Auto merge of #114843 - Zalathar:test-coverage-map, r=oli-obk

coverage: Explicitly test the coverage maps produced by codegen/LLVM

Our existing coverage tests verify the output of end-to-end coverage reports, but we don't have any way to test the specific mapping information (code regions and their associated counters) that are emitted by `rustc_codegen_llvm` and LLVM. That makes it harder to to be confident in changes that would modify those mappings (whether deliberately or accidentally).

This PR addresses that by adding a new `coverage-map` test suite that does the following:
- Compiles test files to LLVM IR assembly (`.ll`)
- Feeds those IR files to a custom tool (`src/tools/coverage-dump`) that extracts and decodes coverage mappings, and prints them in a more human-readable format
- Checks the output of that tool against known-good snapshots

---

I recommend excluding the last commit while reviewing the main changes, because that last commit is just ~40 test files copied over from `tests/run-coverage`, plus their blessed coverage-map snapshots and a readme file. Those snapshots aren't really intended to be checked by hand; they're mostly there to increase the chances that an unintended change to coverage maps will be observable (even if it requires relatively specific circumstances to manifest).

Cargo.lock

@@ -722,6 +722,18 @@ version = "0.8.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "e496a50fda8aacccc86d7529e2c1e0892dbd0f898a6b5645b5561b89c3210efa"
 
+[[package]]
+name = "coverage-dump"
+version = "0.1.0"
+dependencies = [
+ "anyhow",
+ "leb128",
+ "md-5",
+ "miniz_oxide",
+ "regex",
+ "rustc-demangle",
+]
+
 [[package]]
 name = "coverage_test_macros"
 version = "0.0.0"
@@ -2041,6 +2053,12 @@ version = "1.3.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "830d08ce1d1d941e6b30645f1a0eb5643013d835ce3779a5fc208261dbe10f55"
 
+[[package]]
+name = "leb128"
+version = "0.2.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "884e2677b40cc8c339eaefcb701c32ef1fd2493d71118dc0ca4b6a736c93bd67"
+
 [[package]]
 name = "levenshtein"
 version = "1.0.5"

Cargo.toml

@@ -43,6 +43,7 @@ members = [
   "src/tools/generate-windows-sys",
   "src/tools/rustdoc-gui-test",
   "src/tools/opt-dist",
+  "src/tools/coverage-dump",
 ]
 
 exclude = [

src/bootstrap/builder.rs

@@ -703,7 +703,8 @@ impl<'a> Builder<'a> {
                 llvm::Lld,
                 llvm::CrtBeginEnd,
                 tool::RustdocGUITest,
-                tool::OptimizedDist
+                tool::OptimizedDist,
+                tool::CoverageDump,
             ),
             Kind::Check | Kind::Clippy | Kind::Fix => describe!(
                 check::Std,
@@ -725,6 +726,7 @@ impl<'a> Builder<'a> {
                 test::Tidy,
                 test::Ui,
                 test::RunPassValgrind,
+                test::CoverageMap,
                 test::RunCoverage,
                 test::MirOpt,
                 test::Codegen,

src/bootstrap/test.rs

@@ -1340,6 +1340,12 @@ host_test!(RunMakeFullDeps {
 
 default_test!(Assembly { path: "tests/assembly", mode: "assembly", suite: "assembly" });
 
+default_test!(CoverageMap {
+    path: "tests/coverage-map",
+    mode: "coverage-map",
+    suite: "coverage-map"
+});
+
 host_test!(RunCoverage { path: "tests/run-coverage", mode: "run-coverage", suite: "run-coverage" });
 host_test!(RunCoverageRustdoc {
     path: "tests/run-coverage-rustdoc",
@@ -1545,6 +1551,14 @@ note: if you're sure you want to do this, please open an issue as to why. In the
                 .arg(builder.ensure(tool::JsonDocLint { compiler: json_compiler, target }));
         }
 
+        if mode == "coverage-map" {
+            let coverage_dump = builder.ensure(tool::CoverageDump {
+                compiler: compiler.with_stage(0),
+                target: compiler.host,
+            });
+            cmd.arg("--coverage-dump-path").arg(coverage_dump);
+        }
+
         if mode == "run-make" || mode == "run-coverage" {
             let rust_demangler = builder
                 .ensure(tool::RustDemangler {

src/bootstrap/tool.rs

@@ -306,6 +306,7 @@ bootstrap_tool!(
     GenerateWindowsSys, "src/tools/generate-windows-sys", "generate-windows-sys";
     RustdocGUITest, "src/tools/rustdoc-gui-test", "rustdoc-gui-test", is_unstable_tool = true, allow_features = "test";
     OptimizedDist, "src/tools/opt-dist", "opt-dist";
+    CoverageDump, "src/tools/coverage-dump", "coverage-dump";
 );
 
 #[derive(Debug, Copy, Clone, Hash, PartialEq, Eq, Ord, PartialOrd)]

src/tools/compiletest/src/common.rs

@@ -66,6 +66,7 @@ string_enum! {
         JsDocTest => "js-doc-test",
         MirOpt => "mir-opt",
         Assembly => "assembly",
+        CoverageMap => "coverage-map",
         RunCoverage => "run-coverage",
     }
 }
@@ -161,6 +162,9 @@ pub struct Config {
     /// The rust-demangler executable.
     pub rust_demangler_path: Option<PathBuf>,
 
+    /// The coverage-dump executable.
+    pub coverage_dump_path: Option<PathBuf>,
+
     /// The Python executable to use for LLDB and htmldocck.
     pub python: String,
 
@@ -639,6 +643,7 @@ pub const UI_EXTENSIONS: &[&str] = &[
     UI_STDERR_32,
     UI_STDERR_16,
     UI_COVERAGE,
+    UI_COVERAGE_MAP,
 ];
 pub const UI_STDERR: &str = "stderr";
 pub const UI_STDOUT: &str = "stdout";
@@ -649,6 +654,7 @@ pub const UI_STDERR_64: &str = "64bit.stderr";
 pub const UI_STDERR_32: &str = "32bit.stderr";
 pub const UI_STDERR_16: &str = "16bit.stderr";
 pub const UI_COVERAGE: &str = "coverage";
+pub const UI_COVERAGE_MAP: &str = "cov-map";
 
 /// Absolute path to the directory where all output for all tests in the given
 /// `relative_dir` group should reside. Example:

src/tools/compiletest/src/lib.rs

@@ -48,6 +48,7 @@ pub fn parse_config(args: Vec<String>) -> Config {
         .reqopt("", "rustc-path", "path to rustc to use for compiling", "PATH")
         .optopt("", "rustdoc-path", "path to rustdoc to use for compiling", "PATH")
         .optopt("", "rust-demangler-path", "path to rust-demangler to use in tests", "PATH")
+        .optopt("", "coverage-dump-path", "path to coverage-dump to use in tests", "PATH")
         .reqopt("", "python", "path to python to use for doc tests", "PATH")
         .optopt("", "jsondocck-path", "path to jsondocck to use for doc tests", "PATH")
         .optopt("", "jsondoclint-path", "path to jsondoclint to use for doc tests", "PATH")
@@ -218,6 +219,7 @@ pub fn parse_config(args: Vec<String>) -> Config {
         rustc_path: opt_path(matches, "rustc-path"),
         rustdoc_path: matches.opt_str("rustdoc-path").map(PathBuf::from),
         rust_demangler_path: matches.opt_str("rust-demangler-path").map(PathBuf::from),
+        coverage_dump_path: matches.opt_str("coverage-dump-path").map(PathBuf::from),
         python: matches.opt_str("python").unwrap(),
         jsondocck_path: matches.opt_str("jsondocck-path"),
         jsondoclint_path: matches.opt_str("jsondoclint-path"),

src/tools/compiletest/src/runtest.rs

@@ -6,8 +6,8 @@ use crate::common::{Assembly, Incremental, JsDocTest, MirOpt, RunMake, RustdocJs
 use crate::common::{Codegen, CodegenUnits, DebugInfo, Debugger, Rustdoc};
 use crate::common::{CompareMode, FailMode, PassMode};
 use crate::common::{Config, TestPaths};
-use crate::common::{Pretty, RunCoverage, RunPassValgrind};
-use crate::common::{UI_COVERAGE, UI_RUN_STDERR, UI_RUN_STDOUT};
+use crate::common::{CoverageMap, Pretty, RunCoverage, RunPassValgrind};
+use crate::common::{UI_COVERAGE, UI_COVERAGE_MAP, UI_RUN_STDERR, UI_RUN_STDOUT};
 use crate::compute_diff::{write_diff, write_filtered_diff};
 use crate::errors::{self, Error, ErrorKind};
 use crate::header::TestProps;
@@ -254,6 +254,7 @@ impl<'test> TestCx<'test> {
             MirOpt => self.run_mir_opt_test(),
             Assembly => self.run_assembly_test(),
             JsDocTest => self.run_js_doc_test(),
+            CoverageMap => self.run_coverage_map_test(),
             RunCoverage => self.run_coverage_test(),
         }
     }
@@ -467,6 +468,46 @@ impl<'test> TestCx<'test> {
         }
     }
 
+    fn run_coverage_map_test(&self) {
+        let Some(coverage_dump_path) = &self.config.coverage_dump_path else {
+            self.fatal("missing --coverage-dump");
+        };
+
+        let proc_res = self.compile_test_and_save_ir();
+        if !proc_res.status.success() {
+            self.fatal_proc_rec("compilation failed!", &proc_res);
+        }
+        drop(proc_res);
+
+        let llvm_ir_path = self.output_base_name().with_extension("ll");
+
+        let mut dump_command = Command::new(coverage_dump_path);
+        dump_command.arg(llvm_ir_path);
+        let proc_res = self.run_command_to_procres(&mut dump_command);
+        if !proc_res.status.success() {
+            self.fatal_proc_rec("coverage-dump failed!", &proc_res);
+        }
+
+        let kind = UI_COVERAGE_MAP;
+
+        let expected_coverage_dump = self.load_expected_output(kind);
+        let actual_coverage_dump = self.normalize_output(&proc_res.stdout, &[]);
+
+        let coverage_dump_errors = self.compare_output(
+            kind,
+            &actual_coverage_dump,
+            &expected_coverage_dump,
+            self.props.compare_output_lines_by_subset,
+        );
+
+        if coverage_dump_errors > 0 {
+            self.fatal_proc_rec(
+                &format!("{coverage_dump_errors} errors occurred comparing coverage output."),
+                &proc_res,
+            );
+        }
+    }
+
     fn run_coverage_test(&self) {
         let should_run = self.run_if_enabled();
         let proc_res = self.compile_test(should_run, Emit::None);
@@ -650,6 +691,10 @@ impl<'test> TestCx<'test> {
         let mut cmd = Command::new(tool_path);
         configure_cmd_fn(&mut cmd);
 
+        self.run_command_to_procres(&mut cmd)
+    }
+
+    fn run_command_to_procres(&self, cmd: &mut Command) -> ProcRes {
         let output = cmd.output().unwrap_or_else(|_| panic!("failed to exec `{cmd:?}`"));
 
         let proc_res = ProcRes {
@@ -2321,9 +2366,11 @@ impl<'test> TestCx<'test> {
                     }
                 }
                 DebugInfo => { /* debuginfo tests must be unoptimized */ }
-                RunCoverage => {
-                    // Coverage reports are affected by optimization level, and
-                    // the current snapshots assume no optimization by default.
+                CoverageMap | RunCoverage => {
+                    // Coverage mappings and coverage reports are affected by
+                    // optimization level, so they ignore the optimize-tests
+                    // setting and set an optimization level in their mode's
+                    // compile flags (below) or in per-test `compile-flags`.
                 }
                 _ => {
                     rustc.arg("-O");
@@ -2392,8 +2439,22 @@ impl<'test> TestCx<'test> {
 
                 rustc.arg(dir_opt);
             }
+            CoverageMap => {
+                rustc.arg("-Cinstrument-coverage");
+                // These tests only compile to MIR, so they don't need the
+                // profiler runtime to be present.
+                rustc.arg("-Zno-profiler-runtime");
+                // Coverage mappings are sensitive to MIR optimizations, and
+                // the current snapshots assume `opt-level=2` unless overridden
+                // by `compile-flags`.
+                rustc.arg("-Copt-level=2");
+            }
             RunCoverage => {
                 rustc.arg("-Cinstrument-coverage");
+                // Coverage reports are sometimes sensitive to optimizations,
+                // and the current snapshots assume no optimization unless
+                // overridden by `compile-flags`.
+                rustc.arg("-Copt-level=0");
             }
             RunPassValgrind | Pretty | DebugInfo | Codegen | Rustdoc | RustdocJson | RunMake
             | CodegenUnits | JsDocTest | Assembly => {

src/tools/coverage-dump/Cargo.toml

@@ -0,0 +1,14 @@
+[package]
+name = "coverage-dump"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+anyhow = "1.0.71"
+leb128 = "0.2.5"
+md5 = { package = "md-5" , version = "0.10.5" }
+miniz_oxide = "0.7.1"
+regex = "1.8.4"
+rustc-demangle = "0.1.23"

src/tools/coverage-dump/README.md

@@ -0,0 +1,8 @@
+This tool extracts coverage mapping information from an LLVM IR assembly file
+(`.ll`), and prints it in a more human-readable form that can be used for
+snapshot tests.
+
+The output format is mostly arbitrary, so it's OK to change the output as long
+as any affected tests are also re-blessed. However, the output should be
+consistent across different executions on different platforms, so avoid
+printing any information that is platform-specific or non-deterministic.

src/tools/coverage-dump/src/covfun.rs

@@ -0,0 +1,296 @@
+use crate::parser::{unescape_llvm_string_contents, Parser};
+use anyhow::{anyhow, Context};
+use regex::Regex;
+use std::collections::HashMap;
+use std::fmt::{self, Debug, Write as _};
+use std::sync::OnceLock;
+
+pub(crate) fn dump_covfun_mappings(
+    llvm_ir: &str,
+    function_names: &HashMap<u64, String>,
+) -> anyhow::Result<()> {
+    // Extract function coverage entries from the LLVM IR assembly, and associate
+    // each entry with its (demangled) name.
+    let mut covfun_entries = llvm_ir
+        .lines()
+        .filter_map(covfun_line_data)
+        .map(|line_data| (function_names.get(&line_data.name_hash).map(String::as_str), line_data))
+        .collect::<Vec<_>>();
+    covfun_entries.sort_by(|a, b| {
+        // Sort entries primarily by name, to help make the order consistent
+        // across platforms and relatively insensitive to changes.
+        // (Sadly we can't use `sort_by_key` because we would need to return references.)
+        Ord::cmp(&a.0, &b.0)
+            .then_with(|| Ord::cmp(&a.1.is_used, &b.1.is_used))
+            .then_with(|| Ord::cmp(a.1.payload.as_slice(), b.1.payload.as_slice()))
+    });
+
+    for (name, line_data) in &covfun_entries {
+        let name = name.unwrap_or("(unknown)");
+        let unused = if line_data.is_used { "" } else { " (unused)" };
+        println!("Function name: {name}{unused}");
+
+        let payload: &[u8] = &line_data.payload;
+        println!("Raw bytes ({len}): 0x{payload:02x?}", len = payload.len());
+
+        let mut parser = Parser::new(payload);
+
+        let num_files = parser.read_uleb128_u32()?;
+        println!("Number of files: {num_files}");
+
+        for i in 0..num_files {
+            let global_file_id = parser.read_uleb128_u32()?;
+            println!("- file {i} => global file {global_file_id}");
+        }
+
+        let num_expressions = parser.read_uleb128_u32()?;
+        println!("Number of expressions: {num_expressions}");
+
+        let mut expression_resolver = ExpressionResolver::new();
+        for i in 0..num_expressions {
+            let lhs = parser.read_simple_term()?;
+            let rhs = parser.read_simple_term()?;
+            println!("- expression {i} operands: lhs = {lhs:?}, rhs = {rhs:?}");
+            expression_resolver.push_operands(lhs, rhs);
+        }
+
+        for i in 0..num_files {
+            let num_mappings = parser.read_uleb128_u32()?;
+            println!("Number of file {i} mappings: {num_mappings}");
+
+            for _ in 0..num_mappings {
+                let (kind, region) = parser.read_mapping_kind_and_region()?;
+                println!("- {kind:?} at {region:?}");
+
+                match kind {
+                    // Also print expression mappings in resolved form.
+                    MappingKind::Code(term @ CovTerm::Expression { .. })
+                    | MappingKind::Gap(term @ CovTerm::Expression { .. }) => {
+                        println!("    = {}", expression_resolver.format_term(term));
+                    }
+                    // If the mapping is a branch region, print both of its arms
+                    // in resolved form (even if they aren't expressions).
+                    MappingKind::Branch { r#true, r#false } => {
+                        println!("    true  = {}", expression_resolver.format_term(r#true));
+                        println!("    false = {}", expression_resolver.format_term(r#false));
+                    }
+                    _ => (),
+                }
+            }
+        }
+
+        parser.ensure_empty()?;
+        println!();
+    }
+    Ok(())
+}
+
+struct CovfunLineData {
+    name_hash: u64,
+    is_used: bool,
+    payload: Vec<u8>,
+}
+
+/// Checks a line of LLVM IR assembly to see if it contains an `__llvm_covfun`
+/// entry, and if so extracts relevant data in a `CovfunLineData`.
+fn covfun_line_data(line: &str) -> Option<CovfunLineData> {
+    let re = {
+        // We cheat a little bit and match variable names `@__covrec_[HASH]u`
+        // rather than the section name, because the section name is harder to
+        // extract and differs across Linux/Windows/macOS. We also extract the
+        // symbol name hash from the variable name rather than the data, since
+        // it's easier and both should match.
+        static RE: OnceLock<Regex> = OnceLock::new();
+        RE.get_or_init(|| {
+            Regex::new(
+                r#"^@__covrec_(?<name_hash>[0-9A-Z]+)(?<is_used>u)? = .*\[[0-9]+ x i8\] c"(?<payload>[^"]*)".*$"#,
+            )
+            .unwrap()
+        })
+    };
+
+    let captures = re.captures(line)?;
+    let name_hash = u64::from_str_radix(&captures["name_hash"], 16).unwrap();
+    let is_used = captures.name("is_used").is_some();
+    let payload = unescape_llvm_string_contents(&captures["payload"]);
+
+    Some(CovfunLineData { name_hash, is_used, payload })
+}
+
+// Extra parser methods only needed when parsing `covfun` payloads.
+impl<'a> Parser<'a> {
+    fn read_simple_term(&mut self) -> anyhow::Result<CovTerm> {
+        let raw_term = self.read_uleb128_u32()?;
+        CovTerm::decode(raw_term).context("decoding term")
+    }
+
+    fn read_mapping_kind_and_region(&mut self) -> anyhow::Result<(MappingKind, MappingRegion)> {
+        let mut kind = self.read_raw_mapping_kind()?;
+        let mut region = self.read_raw_mapping_region()?;
+
+        const HIGH_BIT: u32 = 1u32 << 31;
+        if region.end_column & HIGH_BIT != 0 {
+            region.end_column &= !HIGH_BIT;
+            kind = match kind {
+                MappingKind::Code(term) => MappingKind::Gap(term),
+                // LLVM's coverage mapping reader will actually handle this
+                // case without complaint, but the result is almost certainly
+                // a meaningless implementation artifact.
+                _ => return Err(anyhow!("unexpected base kind for gap region: {kind:?}")),
+            }
+        }
+
+        Ok((kind, region))
+    }
+
+    fn read_raw_mapping_kind(&mut self) -> anyhow::Result<MappingKind> {
+        let raw_mapping_kind = self.read_uleb128_u32()?;
+        if let Some(term) = CovTerm::decode(raw_mapping_kind) {
+            return Ok(MappingKind::Code(term));
+        }
+
+        assert_eq!(raw_mapping_kind & 0b11, 0);
+        assert_ne!(raw_mapping_kind, 0);
+
+        let (high, is_expansion) = (raw_mapping_kind >> 3, raw_mapping_kind & 0b100 != 0);
+        if is_expansion {
+            Ok(MappingKind::Expansion(high))
+        } else {
+            match high {
+                0 => unreachable!("zero kind should have already been handled as a code mapping"),
+                2 => Ok(MappingKind::Skip),
+                4 => {
+                    let r#true = self.read_simple_term()?;
+                    let r#false = self.read_simple_term()?;
+                    Ok(MappingKind::Branch { r#true, r#false })
+                }
+                _ => Err(anyhow!("unknown mapping kind: {raw_mapping_kind:#x}")),
+            }
+        }
+    }
+
+    fn read_raw_mapping_region(&mut self) -> anyhow::Result<MappingRegion> {
+        let start_line_offset = self.read_uleb128_u32()?;
+        let start_column = self.read_uleb128_u32()?;
+        let end_line_offset = self.read_uleb128_u32()?;
+        let end_column = self.read_uleb128_u32()?;
+        Ok(MappingRegion { start_line_offset, start_column, end_line_offset, end_column })
+    }
+}
+
+/// Enum that can hold a constant zero value, the ID of an physical coverage
+/// counter, or the ID (and operation) of a coverage-counter expression.
+///
+/// Terms are used as the operands of coverage-counter expressions, as the arms
+/// of branch mappings, and as the value of code/gap mappings.
+#[derive(Clone, Copy, Debug)]
+pub(crate) enum CovTerm {
+    Zero,
+    Counter(u32),
+    Expression(u32, Op),
+}
+
+/// Operator (addition or subtraction) used by an expression.
+#[derive(Clone, Copy, Debug)]
+pub(crate) enum Op {
+    Sub,
+    Add,
+}
+
+impl CovTerm {
+    pub(crate) fn decode(input: u32) -> Option<Self> {
+        let (high, tag) = (input >> 2, input & 0b11);
+        match tag {
+            0b00 if high == 0 => Some(Self::Zero),
+            0b01 => Some(Self::Counter(high)),
+            0b10 => Some(Self::Expression(high, Op::Sub)),
+            0b11 => Some(Self::Expression(high, Op::Add)),
+            // When reading expression operands or branch arms, the LLVM coverage
+            // mapping reader will always interpret a `0b00` tag as a zero
+            // term, even when the high bits are non-zero.
+            // We treat that case as failure instead, so that this code can be
+            // shared by the full mapping-kind reader as well.
+            _ => None,
+        }
+    }
+}
+
+#[derive(Debug)]
+enum MappingKind {
+    Code(CovTerm),
+    Gap(CovTerm),
+    Expansion(u32),
+    Skip,
+    // Using raw identifiers here makes the dump output a little bit nicer
+    // (via the derived Debug), at the expense of making this tool's source
+    // code a little bit uglier.
+    Branch { r#true: CovTerm, r#false: CovTerm },
+}
+
+struct MappingRegion {
+    /// Offset of this region's start line, relative to the *start line* of
+    /// the *previous mapping* (or 0). Line numbers are 1-based.
+    start_line_offset: u32,
+    /// This region's start column, absolute and 1-based.
+    start_column: u32,
+    /// Offset of this region's end line, relative to the *this mapping's*
+    /// start line. Line numbers are 1-based.
+    end_line_offset: u32,
+    /// This region's end column, absolute, 1-based, and exclusive.
+    ///
+    /// If the highest bit is set, that bit is cleared and the associated
+    /// mapping becomes a gap region mapping.
+    end_column: u32,
+}
+
+impl Debug for MappingRegion {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        write!(
+            f,
+            "(prev + {}, {}) to (start + {}, {})",
+            self.start_line_offset, self.start_column, self.end_line_offset, self.end_column
+        )
+    }
+}
+
+/// Helper type that prints expressions in a "resolved" form, so that
+/// developers reading the dump don't need to resolve expressions by hand.
+struct ExpressionResolver {
+    operands: Vec<(CovTerm, CovTerm)>,
+}
+
+impl ExpressionResolver {
+    fn new() -> Self {
+        Self { operands: Vec::new() }
+    }
+
+    fn push_operands(&mut self, lhs: CovTerm, rhs: CovTerm) {
+        self.operands.push((lhs, rhs));
+    }
+
+    fn format_term(&self, term: CovTerm) -> String {
+        let mut output = String::new();
+        self.write_term(&mut output, term);
+        output
+    }
+
+    fn write_term(&self, output: &mut String, term: CovTerm) {
+        match term {
+            CovTerm::Zero => output.push_str("Zero"),
+            CovTerm::Counter(id) => write!(output, "c{id}").unwrap(),
+            CovTerm::Expression(id, op) => {
+                let (lhs, rhs) = self.operands[id as usize];
+                let op = match op {
+                    Op::Sub => "-",
+                    Op::Add => "+",
+                };
+
+                output.push('(');
+                self.write_term(output, lhs);
+                write!(output, " {op} ").unwrap();
+                self.write_term(output, rhs);
+                output.push(')');
+            }
+        }
+    }
+}

src/tools/coverage-dump/src/main.rs

@@ -0,0 +1,17 @@
+mod covfun;
+mod parser;
+mod prf_names;
+
+fn main() -> anyhow::Result<()> {
+    use anyhow::Context as _;
+
+    let args = std::env::args().collect::<Vec<_>>();
+
+    let llvm_ir_path = args.get(1).context("LLVM IR file not specified")?;
+    let llvm_ir = std::fs::read_to_string(llvm_ir_path).context("couldn't read LLVM IR file")?;
+
+    let function_names = crate::prf_names::make_function_names_table(&llvm_ir)?;
+    crate::covfun::dump_covfun_mappings(&llvm_ir, &function_names)?;
+
+    Ok(())
+}

src/tools/coverage-dump/src/parser.rs

@@ -0,0 +1,80 @@
+#[cfg(test)]
+mod tests;
+
+use anyhow::ensure;
+use regex::bytes;
+use std::sync::OnceLock;
+
+/// Given the raw contents of a string literal in LLVM IR assembly, decodes any
+/// backslash escapes and returns a vector containing the resulting byte string.
+pub(crate) fn unescape_llvm_string_contents(contents: &str) -> Vec<u8> {
+    let escape_re = {
+        static RE: OnceLock<bytes::Regex> = OnceLock::new();
+        // LLVM IR supports two string escapes: `\\` and `\xx`.
+        RE.get_or_init(|| bytes::Regex::new(r"\\\\|\\([0-9A-Za-z]{2})").unwrap())
+    };
+
+    fn u8_from_hex_digits(digits: &[u8]) -> u8 {
+        // We know that the input contains exactly 2 hex digits, so these calls
+        // should never fail.
+        assert_eq!(digits.len(), 2);
+        let digits = std::str::from_utf8(digits).unwrap();
+        u8::from_str_radix(digits, 16).unwrap()
+    }
+
+    escape_re
+        .replace_all(contents.as_bytes(), |captures: &bytes::Captures<'_>| {
+            let byte = match captures.get(1) {
+                None => b'\\',
+                Some(hex_digits) => u8_from_hex_digits(hex_digits.as_bytes()),
+            };
+            [byte]
+        })
+        .into_owned()
+}
+
+pub(crate) struct Parser<'a> {
+    rest: &'a [u8],
+}
+
+impl<'a> Parser<'a> {
+    pub(crate) fn new(input: &'a [u8]) -> Self {
+        Self { rest: input }
+    }
+
+    pub(crate) fn ensure_empty(self) -> anyhow::Result<()> {
+        ensure!(self.rest.is_empty(), "unparsed bytes: 0x{:02x?}", self.rest);
+        Ok(())
+    }
+
+    pub(crate) fn read_n_bytes(&mut self, n: usize) -> anyhow::Result<&'a [u8]> {
+        ensure!(n <= self.rest.len());
+
+        let (bytes, rest) = self.rest.split_at(n);
+        self.rest = rest;
+        Ok(bytes)
+    }
+
+    pub(crate) fn read_uleb128_u32(&mut self) -> anyhow::Result<u32> {
+        self.read_uleb128_u64_and_convert()
+    }
+
+    pub(crate) fn read_uleb128_usize(&mut self) -> anyhow::Result<usize> {
+        self.read_uleb128_u64_and_convert()
+    }
+
+    fn read_uleb128_u64_and_convert<T>(&mut self) -> anyhow::Result<T>
+    where
+        T: TryFrom<u64> + 'static,
+        T::Error: std::error::Error + Send + Sync,
+    {
+        let mut temp_rest = self.rest;
+        let raw_value: u64 = leb128::read::unsigned(&mut temp_rest)?;
+        let converted_value = T::try_from(raw_value)?;
+
+        // Only update `self.rest` if the above steps succeeded, so that the
+        // parser position can be used for error reporting if desired.
+        self.rest = temp_rest;
+        Ok(converted_value)
+    }
+}

src/tools/coverage-dump/src/parser/tests.rs

@@ -0,0 +1,38 @@
+use super::unescape_llvm_string_contents;
+
+// WARNING: These tests don't necessarily run in CI, and were mainly used to
+// help track down problems when originally developing this tool.
+// (The tool is still tested indirectly by snapshot tests that rely on it.)
+
+// Tests for `unescape_llvm_string_contents`:
+
+#[test]
+fn unescape_empty() {
+    assert_eq!(unescape_llvm_string_contents(""), &[]);
+}
+
+#[test]
+fn unescape_noop() {
+    let input = "The quick brown fox jumps over the lazy dog.";
+    assert_eq!(unescape_llvm_string_contents(input), input.as_bytes());
+}
+
+#[test]
+fn unescape_backslash() {
+    let input = r"\\Hello\\world\\";
+    assert_eq!(unescape_llvm_string_contents(input), r"\Hello\world\".as_bytes());
+}
+
+#[test]
+fn unescape_hex() {
+    let input = r"\01\02\03\04\0a\0b\0C\0D\fd\fE\FF";
+    let expected: &[u8] = &[0x01, 0x02, 0x03, 0x04, 0x0a, 0x0b, 0x0c, 0x0d, 0xfd, 0xfe, 0xff];
+    assert_eq!(unescape_llvm_string_contents(input), expected);
+}
+
+#[test]
+fn unescape_mixed() {
+    let input = r"\\01.\5c\5c";
+    let expected: &[u8] = br"\01.\\";
+    assert_eq!(unescape_llvm_string_contents(input), expected);
+}

src/tools/coverage-dump/src/prf_names.rs

@@ -0,0 +1,87 @@
+use crate::parser::{unescape_llvm_string_contents, Parser};
+use anyhow::{anyhow, ensure};
+use regex::Regex;
+use std::collections::HashMap;
+use std::sync::OnceLock;
+
+/// Scans through the contents of an LLVM IR assembly file to find `__llvm_prf_names`
+/// entries, decodes them, and creates a table that maps name hash values to
+/// (demangled) function names.
+pub(crate) fn make_function_names_table(llvm_ir: &str) -> anyhow::Result<HashMap<u64, String>> {
+    fn prf_names_payload(line: &str) -> Option<&str> {
+        let re = {
+            // We cheat a little bit and match the variable name `@__llvm_prf_nm`
+            // rather than the section name, because the section name is harder
+            // to extract and differs across Linux/Windows/macOS.
+            static RE: OnceLock<Regex> = OnceLock::new();
+            RE.get_or_init(|| {
+                Regex::new(r#"^@__llvm_prf_nm =.*\[[0-9]+ x i8\] c"([^"]*)".*$"#).unwrap()
+            })
+        };
+
+        let payload = re.captures(line)?.get(1).unwrap().as_str();
+        Some(payload)
+    }
+
+    /// LLVM's profiler/coverage metadata often uses an MD5 hash truncated to
+    /// 64 bits as a way to associate data stored in different tables/sections.
+    fn truncated_md5(bytes: &[u8]) -> u64 {
+        use md5::{Digest, Md5};
+        let mut hasher = Md5::new();
+        hasher.update(bytes);
+        let hash: [u8; 8] = hasher.finalize().as_slice()[..8].try_into().unwrap();
+        // The truncated hash is explicitly little-endian, regardless of host
+        // or target platform. (See `MD5Result::low` in LLVM's `MD5.h`.)
+        u64::from_le_bytes(hash)
+    }
+
+    fn demangle_if_able(symbol_name_bytes: &[u8]) -> anyhow::Result<String> {
+        // In practice, raw symbol names should always be ASCII.
+        let symbol_name_str = std::str::from_utf8(symbol_name_bytes)?;
+        match rustc_demangle::try_demangle(symbol_name_str) {
+            Ok(d) => Ok(format!("{d:#}")),
+            // If demangling failed, don't treat it as an error. This lets us
+            // run the dump tool against non-Rust coverage maps produced by
+            // `clang`, for testing purposes.
+            Err(_) => Ok(format!("(couldn't demangle) {symbol_name_str}")),
+        }
+    }
+
+    let mut map = HashMap::new();
+
+    for payload in llvm_ir.lines().filter_map(prf_names_payload).map(unescape_llvm_string_contents)
+    {
+        let mut parser = Parser::new(&payload);
+        let uncompressed_len = parser.read_uleb128_usize()?;
+        let compressed_len = parser.read_uleb128_usize()?;
+
+        let uncompressed_bytes_vec;
+        let uncompressed_bytes: &[u8] = if compressed_len == 0 {
+            // The symbol name bytes are uncompressed, so read them directly.
+            parser.read_n_bytes(uncompressed_len)?
+        } else {
+            // The symbol name bytes are compressed, so read and decompress them.
+            let compressed_bytes = parser.read_n_bytes(compressed_len)?;
+
+            uncompressed_bytes_vec = miniz_oxide::inflate::decompress_to_vec_zlib_with_limit(
+                compressed_bytes,
+                uncompressed_len,
+            )
+            .map_err(|e| anyhow!("{e:?}"))?;
+            ensure!(uncompressed_bytes_vec.len() == uncompressed_len);
+
+            &uncompressed_bytes_vec
+        };
+
+        // Symbol names in the payload are separated by `0x01` bytes.
+        for raw_name in uncompressed_bytes.split(|&b| b == 0x01) {
+            let hash = truncated_md5(raw_name);
+            let demangled = demangle_if_able(raw_name)?;
+            map.insert(hash, demangled);
+        }
+
+        parser.ensure_empty()?;
+    }
+
+    Ok(map)
+}

tests/coverage-map/README.md

@@ -0,0 +1,13 @@
+The tests in `./status-quo` were copied from `tests/run-coverage` in order to
+capture the current behavior of the instrumentor on non-trivial programs.
+The actual mappings have not been closely inspected.
+
+## Maintenance note
+
+These tests can be sensitive to small changes in MIR spans or MIR control flow,
+especially in HIR-to-MIR lowering or MIR optimizations.
+
+If you haven't touched the coverage code directly, and the `run-coverage` test
+suite still works, then it should usually be OK to just `--bless` these
+coverage mapping tests as necessary, without worrying too much about the exact
+changes.

tests/coverage-map/if.cov-map

@@ -0,0 +1,15 @@
+Function name: if::main
+Raw bytes (28): 0x[01, 01, 02, 01, 05, 05, 02, 04, 01, 03, 01, 02, 0c, 05, 02, 0d, 02, 06, 02, 02, 06, 00, 07, 07, 01, 05, 01, 02]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 2
+- expression 0 operands: lhs = Counter(0), rhs = Counter(1)
+- expression 1 operands: lhs = Counter(1), rhs = Expression(0, Sub)
+Number of file 0 mappings: 4
+- Code(Counter(0)) at (prev + 3, 1) to (start + 2, 12)
+- Code(Counter(1)) at (prev + 2, 13) to (start + 2, 6)
+- Code(Expression(0, Sub)) at (prev + 2, 6) to (start + 0, 7)
+    = (c0 - c1)
+- Code(Expression(1, Add)) at (prev + 1, 5) to (start + 1, 2)
+    = (c1 + (c0 - c1))
+

tests/coverage-map/if.rs

@@ -0,0 +1,9 @@
+// compile-flags: --edition=2021
+
+fn main() {
+    let cond = std::env::args().len() == 1;
+    if cond {
+        println!("true");
+    }
+    println!("done");
+}

tests/coverage-map/long_and_wide.cov-map

@@ -0,0 +1,32 @@
+Function name: long_and_wide::far_function
+Raw bytes (10): 0x[01, 01, 00, 01, 01, 96, 01, 01, 00, 15]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 0
+Number of file 0 mappings: 1
+- Code(Counter(0)) at (prev + 150, 1) to (start + 0, 21)
+
+Function name: long_and_wide::long_function
+Raw bytes (10): 0x[01, 01, 00, 01, 01, 10, 01, 84, 01, 02]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 0
+Number of file 0 mappings: 1
+- Code(Counter(0)) at (prev + 16, 1) to (start + 132, 2)
+
+Function name: long_and_wide::main
+Raw bytes (9): 0x[01, 01, 00, 01, 01, 07, 01, 04, 02]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 0
+Number of file 0 mappings: 1
+- Code(Counter(0)) at (prev + 7, 1) to (start + 4, 2)
+
+Function name: long_and_wide::wide_function
+Raw bytes (10): 0x[01, 01, 00, 01, 01, 0e, 01, 00, 8b, 01]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 0
+Number of file 0 mappings: 1
+- Code(Counter(0)) at (prev + 14, 1) to (start + 0, 139)
+

tests/coverage-map/long_and_wide.rs

@@ -0,0 +1,150 @@
+// compile-flags: --edition=2021
+// ignore-tidy-linelength
+
+// This file deliberately contains line and column numbers larger than 127,
+// to verify that `coverage-dump`'s ULEB128 parser can handle them.
+
+fn main() {
+    wide_function();
+    long_function();
+    far_function();
+}
+
+#[rustfmt::skip]
+fn wide_function() { /*                                                                                                           */ (); }
+
+fn long_function() {
+    //
+    //
+    //
+    //
+    //
+    //
+    //
+    //
+    //
+    //
+    //
+    //
+    //
+    //
+    //
+    //
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+    //
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+    //
+    //
+    //
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+    //
+    //
+    //
+    //
+    //
+    //
+    //
+    //
+    //
+    //
+    //
+    //
+    //
+    //
+    //
+    //
+    //
+    //
+    //
+    //
+    //
+    //
+    //
+    //
+    //
+    //
+    //
+    //
+    //
+    //
+    //
+    //
+    //
+    //
+    //
+    //
+    //
+    //
+    //
+    //
+    //
+    //
+    //
+    //
+    //
+    //
+    //
+    //
+    //
+    //
+    //
+    //
+    //
+    //
+    //
+    //
+    //
+    //
+    //
+    //
+    //
+    //
+    //
+    //
+    //
+    //
+    //
+    //
+    //
+    //
+    //
+    //
+    //
+    //
+    //
+    //
+    //
+    //
+    //
+    //
+    //
+    //
+    //
+    //
+    //
+    //
+    //
+    //
+    //
+    //
+    //
+    //
+    //
+    //
+    //
+    //
+    //
+    //
+    //
+    //
+    //
+    //
+    //
+    //
+    //
+    //
+    //
+    //
+}
+
+fn far_function() {}

tests/coverage-map/status-quo/abort.cov-map

@@ -0,0 +1,57 @@
+Function name: abort::main
+Raw bytes (105): 0x[01, 01, 12, 01, 47, 05, 09, 03, 0d, 42, 11, 03, 0d, 11, 3e, 42, 11, 03, 0d, 3b, 15, 11, 3e, 42, 11, 03, 0d, 15, 36, 3b, 15, 11, 3e, 42, 11, 03, 0d, 05, 09, 0d, 01, 0d, 01, 01, 1b, 03, 02, 0b, 00, 18, 42, 01, 0c, 00, 19, 11, 00, 1a, 02, 0a, 3e, 02, 0a, 00, 0b, 3b, 02, 0c, 00, 19, 15, 00, 1a, 00, 31, 36, 00, 31, 00, 32, 33, 04, 0c, 00, 19, 05, 00, 1a, 00, 31, 09, 00, 31, 00, 32, 47, 01, 09, 00, 17, 0d, 02, 05, 01, 02]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 18
+- expression 0 operands: lhs = Counter(0), rhs = Expression(17, Add)
+- expression 1 operands: lhs = Counter(1), rhs = Counter(2)
+- expression 2 operands: lhs = Expression(0, Add), rhs = Counter(3)
+- expression 3 operands: lhs = Expression(16, Sub), rhs = Counter(4)
+- expression 4 operands: lhs = Expression(0, Add), rhs = Counter(3)
+- expression 5 operands: lhs = Counter(4), rhs = Expression(15, Sub)
+- expression 6 operands: lhs = Expression(16, Sub), rhs = Counter(4)
+- expression 7 operands: lhs = Expression(0, Add), rhs = Counter(3)
+- expression 8 operands: lhs = Expression(14, Add), rhs = Counter(5)
+- expression 9 operands: lhs = Counter(4), rhs = Expression(15, Sub)
+- expression 10 operands: lhs = Expression(16, Sub), rhs = Counter(4)
+- expression 11 operands: lhs = Expression(0, Add), rhs = Counter(3)
+- expression 12 operands: lhs = Counter(5), rhs = Expression(13, Sub)
+- expression 13 operands: lhs = Expression(14, Add), rhs = Counter(5)
+- expression 14 operands: lhs = Counter(4), rhs = Expression(15, Sub)
+- expression 15 operands: lhs = Expression(16, Sub), rhs = Counter(4)
+- expression 16 operands: lhs = Expression(0, Add), rhs = Counter(3)
+- expression 17 operands: lhs = Counter(1), rhs = Counter(2)
+Number of file 0 mappings: 13
+- Code(Counter(0)) at (prev + 13, 1) to (start + 1, 27)
+- Code(Expression(0, Add)) at (prev + 2, 11) to (start + 0, 24)
+    = (c0 + (c1 + c2))
+- Code(Expression(16, Sub)) at (prev + 1, 12) to (start + 0, 25)
+    = ((c0 + (c1 + c2)) - c3)
+- Code(Counter(4)) at (prev + 0, 26) to (start + 2, 10)
+- Code(Expression(15, Sub)) at (prev + 2, 10) to (start + 0, 11)
+    = (((c0 + (c1 + c2)) - c3) - c4)
+- Code(Expression(14, Add)) at (prev + 2, 12) to (start + 0, 25)
+    = (c4 + (((c0 + (c1 + c2)) - c3) - c4))
+- Code(Counter(5)) at (prev + 0, 26) to (start + 0, 49)
+- Code(Expression(13, Sub)) at (prev + 0, 49) to (start + 0, 50)
+    = ((c4 + (((c0 + (c1 + c2)) - c3) - c4)) - c5)
+- Code(Expression(12, Add)) at (prev + 4, 12) to (start + 0, 25)
+    = (c5 + ((c4 + (((c0 + (c1 + c2)) - c3) - c4)) - c5))
+- Code(Counter(1)) at (prev + 0, 26) to (start + 0, 49)
+- Code(Counter(2)) at (prev + 0, 49) to (start + 0, 50)
+- Code(Expression(17, Add)) at (prev + 1, 9) to (start + 0, 23)
+    = (c1 + c2)
+- Code(Counter(3)) at (prev + 2, 5) to (start + 1, 2)
+
+Function name: abort::might_abort
+Raw bytes (21): 0x[01, 01, 01, 01, 05, 03, 01, 04, 01, 01, 14, 05, 02, 09, 01, 24, 02, 02, 0c, 03, 02]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 1
+- expression 0 operands: lhs = Counter(0), rhs = Counter(1)
+Number of file 0 mappings: 3
+- Code(Counter(0)) at (prev + 4, 1) to (start + 1, 20)
+- Code(Counter(1)) at (prev + 2, 9) to (start + 1, 36)
+- Code(Expression(0, Sub)) at (prev + 2, 12) to (start + 3, 2)
+    = (c0 - c1)
+

tests/coverage-map/status-quo/abort.rs

@@ -0,0 +1,66 @@
+#![feature(c_unwind)]
+#![allow(unused_assignments)]
+
+extern "C" fn might_abort(should_abort: bool) {
+    if should_abort {
+        println!("aborting...");
+        panic!("panics and aborts");
+    } else {
+        println!("Don't Panic");
+    }
+}
+
+fn main() -> Result<(), u8> {
+    let mut countdown = 10;
+    while countdown > 0 {
+        if countdown < 5 {
+            might_abort(false);
+        }
+        // See discussion (below the `Notes` section) on coverage results for the closing brace.
+        if countdown < 5 { might_abort(false); } // Counts for different regions on one line.
+        // For the following example, the closing brace is the last character on the line.
+        // This shows the character after the closing brace is highlighted, even if that next
+        // character is a newline.
+        if countdown < 5 { might_abort(false); }
+        countdown -= 1;
+    }
+    Ok(())
+}
+
+// Notes:
+//   1. Compare this program and its coverage results to those of the similar tests
+//      `panic_unwind.rs` and `try_error_result.rs`.
+//   2. This test confirms the coverage generated when a program includes `UnwindAction::Terminate`.
+//   3. The test does not invoke the abort. By executing to a successful completion, the coverage
+//      results show where the program did and did not execute.
+//   4. If the program actually aborted, the coverage counters would not be saved (which "works as
+//      intended"). Coverage results would show no executed coverage regions.
+//   6. If `should_abort` is `true` and the program aborts, the program exits with a `132` status
+//      (on Linux at least).
+
+/*
+
+Expect the following coverage results:
+
+```text
+    16|     11|    while countdown > 0 {
+    17|     10|        if countdown < 5 {
+    18|      4|            might_abort(false);
+    19|      6|        }
+```
+
+This is actually correct.
+
+The condition `countdown < 5` executed 10 times (10 loop iterations).
+
+It evaluated to `true` 4 times, and executed the `might_abort()` call.
+
+It skipped the body of the `might_abort()` call 6 times. If an `if` does not include an explicit
+`else`, the coverage implementation injects a counter, at the character immediately after the `if`s
+closing brace, to count the "implicit" `else`. This is the only way to capture the coverage of the
+non-true condition.
+
+As another example of why this is important, say the condition was `countdown < 50`, which is always
+`true`. In that case, we wouldn't have a test for what happens if `might_abort()` is not called.
+The closing brace would have a count of `0`, highlighting the missed coverage.
+*/

tests/coverage-map/status-quo/assert.cov-map

@@ -0,0 +1,40 @@
+Function name: assert::main
+Raw bytes (65): 0x[01, 01, 08, 01, 1b, 05, 1f, 09, 0d, 03, 11, 16, 05, 03, 11, 05, 1f, 09, 0d, 09, 01, 09, 01, 01, 1b, 03, 02, 0b, 00, 18, 16, 01, 0c, 00, 1a, 05, 00, 1b, 02, 0a, 12, 02, 13, 00, 20, 09, 00, 21, 02, 0a, 0d, 02, 0a, 00, 0b, 1b, 01, 09, 00, 17, 11, 02, 05, 01, 02]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 8
+- expression 0 operands: lhs = Counter(0), rhs = Expression(6, Add)
+- expression 1 operands: lhs = Counter(1), rhs = Expression(7, Add)
+- expression 2 operands: lhs = Counter(2), rhs = Counter(3)
+- expression 3 operands: lhs = Expression(0, Add), rhs = Counter(4)
+- expression 4 operands: lhs = Expression(5, Sub), rhs = Counter(1)
+- expression 5 operands: lhs = Expression(0, Add), rhs = Counter(4)
+- expression 6 operands: lhs = Counter(1), rhs = Expression(7, Add)
+- expression 7 operands: lhs = Counter(2), rhs = Counter(3)
+Number of file 0 mappings: 9
+- Code(Counter(0)) at (prev + 9, 1) to (start + 1, 27)
+- Code(Expression(0, Add)) at (prev + 2, 11) to (start + 0, 24)
+    = (c0 + (c1 + (c2 + c3)))
+- Code(Expression(5, Sub)) at (prev + 1, 12) to (start + 0, 26)
+    = ((c0 + (c1 + (c2 + c3))) - c4)
+- Code(Counter(1)) at (prev + 0, 27) to (start + 2, 10)
+- Code(Expression(4, Sub)) at (prev + 2, 19) to (start + 0, 32)
+    = (((c0 + (c1 + (c2 + c3))) - c4) - c1)
+- Code(Counter(2)) at (prev + 0, 33) to (start + 2, 10)
+- Code(Counter(3)) at (prev + 2, 10) to (start + 0, 11)
+- Code(Expression(6, Add)) at (prev + 1, 9) to (start + 0, 23)
+    = (c1 + (c2 + c3))
+- Code(Counter(4)) at (prev + 2, 5) to (start + 1, 2)
+
+Function name: assert::might_fail_assert
+Raw bytes (21): 0x[01, 01, 01, 01, 05, 03, 01, 04, 01, 02, 0f, 02, 02, 25, 00, 3d, 05, 01, 01, 00, 02]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 1
+- expression 0 operands: lhs = Counter(0), rhs = Counter(1)
+Number of file 0 mappings: 3
+- Code(Counter(0)) at (prev + 4, 1) to (start + 2, 15)
+- Code(Expression(0, Sub)) at (prev + 2, 37) to (start + 0, 61)
+    = (c0 - c1)
+- Code(Counter(1)) at (prev + 1, 1) to (start + 0, 2)
+

tests/coverage-map/status-quo/assert.rs

@@ -0,0 +1,32 @@
+#![allow(unused_assignments)]
+// failure-status: 101
+
+fn might_fail_assert(one_plus_one: u32) {
+    println!("does 1 + 1 = {}?", one_plus_one);
+    assert_eq!(1 + 1, one_plus_one, "the argument was wrong");
+}
+
+fn main() -> Result<(), u8> {
+    let mut countdown = 10;
+    while countdown > 0 {
+        if countdown == 1 {
+            might_fail_assert(3);
+        } else if countdown < 5 {
+            might_fail_assert(2);
+        }
+        countdown -= 1;
+    }
+    Ok(())
+}
+
+// Notes:
+//   1. Compare this program and its coverage results to those of the very similar test
+//      `panic_unwind.rs`, and similar tests `abort.rs` and `try_error_result.rs`.
+//   2. This test confirms the coverage generated when a program passes or fails an `assert!()` or
+//      related `assert_*!()` macro.
+//   3. Notably, the `assert` macros *do not* generate `TerminatorKind::Assert`. The macros produce
+//      conditional expressions, `TerminatorKind::SwitchInt` branches, and a possible call to
+//      `begin_panic_fmt()` (that begins a panic unwind, if the assertion test fails).
+//   4. `TerminatoKind::Assert` is, however, also present in the MIR generated for this test
+//      (and in many other coverage tests). The `Assert` terminator is typically generated by the
+//      Rust compiler to check for runtime failures, such as numeric overflows.

tests/coverage-map/status-quo/async.cov-map

@@ -0,0 +1,340 @@
+Function name: async::c
+Raw bytes (9): 0x[01, 01, 00, 01, 01, 05, 01, 00, 19]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 0
+Number of file 0 mappings: 1
+- Code(Counter(0)) at (prev + 5, 1) to (start + 0, 25)
+
+Function name: async::c::{closure#0}
+Raw bytes (28): 0x[01, 01, 02, 01, 05, 05, 02, 04, 01, 05, 19, 01, 0e, 05, 02, 09, 00, 0a, 02, 02, 09, 00, 0a, 07, 02, 01, 00, 02]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 2
+- expression 0 operands: lhs = Counter(0), rhs = Counter(1)
+- expression 1 operands: lhs = Counter(1), rhs = Expression(0, Sub)
+Number of file 0 mappings: 4
+- Code(Counter(0)) at (prev + 5, 25) to (start + 1, 14)
+- Code(Counter(1)) at (prev + 2, 9) to (start + 0, 10)
+- Code(Expression(0, Sub)) at (prev + 2, 9) to (start + 0, 10)
+    = (c0 - c1)
+- Code(Expression(1, Add)) at (prev + 2, 1) to (start + 0, 2)
+    = (c1 + (c0 - c1))
+
+Function name: async::d
+Raw bytes (9): 0x[01, 01, 00, 01, 01, 0d, 01, 00, 14]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 0
+Number of file 0 mappings: 1
+- Code(Counter(0)) at (prev + 13, 1) to (start + 0, 20)
+
+Function name: async::d::{closure#0}
+Raw bytes (9): 0x[01, 01, 00, 01, 01, 0d, 14, 00, 19]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 0
+Number of file 0 mappings: 1
+- Code(Counter(0)) at (prev + 13, 20) to (start + 0, 25)
+
+Function name: async::e (unused)
+Raw bytes (9): 0x[01, 01, 00, 01, 01, 0f, 01, 00, 14]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 0
+Number of file 0 mappings: 1
+- Code(Counter(0)) at (prev + 15, 1) to (start + 0, 20)
+
+Function name: async::e::{closure#0} (unused)
+Raw bytes (9): 0x[01, 01, 00, 01, 01, 0f, 14, 00, 19]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 0
+Number of file 0 mappings: 1
+- Code(Counter(0)) at (prev + 15, 20) to (start + 0, 25)
+
+Function name: async::executor::block_on::<core::pin::Pin<&mut async::i::{closure#0}>>
+Raw bytes (44): 0x[01, 01, 05, 0b, 05, 01, 05, 01, 05, 02, 00, 02, 00, 06, 01, 6e, 05, 0a, 36, 02, 0d, 20, 00, 23, 0b, 00, 27, 00, 49, 0f, 01, 17, 00, 1a, 05, 01, 0e, 00, 0f, 13, 02, 05, 00, 06]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 5
+- expression 0 operands: lhs = Expression(2, Add), rhs = Counter(1)
+- expression 1 operands: lhs = Counter(0), rhs = Counter(1)
+- expression 2 operands: lhs = Counter(0), rhs = Counter(1)
+- expression 3 operands: lhs = Expression(0, Sub), rhs = Zero
+- expression 4 operands: lhs = Expression(0, Sub), rhs = Zero
+Number of file 0 mappings: 6
+- Code(Counter(0)) at (prev + 110, 5) to (start + 10, 54)
+- Code(Expression(0, Sub)) at (prev + 13, 32) to (start + 0, 35)
+    = ((c0 + c1) - c1)
+- Code(Expression(2, Add)) at (prev + 0, 39) to (start + 0, 73)
+    = (c0 + c1)
+- Code(Expression(3, Add)) at (prev + 1, 23) to (start + 0, 26)
+    = (((c0 + c1) - c1) + Zero)
+- Code(Counter(1)) at (prev + 1, 14) to (start + 0, 15)
+- Code(Expression(4, Add)) at (prev + 2, 5) to (start + 0, 6)
+    = (((c0 + c1) - c1) + Zero)
+
+Function name: async::executor::block_on::VTABLE::{closure#0}
+Raw bytes (9): 0x[01, 01, 00, 01, 01, 72, 11, 00, 33]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 0
+Number of file 0 mappings: 1
+- Code(Counter(0)) at (prev + 114, 17) to (start + 0, 51)
+
+Function name: async::executor::block_on::VTABLE::{closure#1}
+Raw bytes (9): 0x[01, 01, 00, 01, 01, 73, 11, 00, 33]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 0
+Number of file 0 mappings: 1
+- Code(Counter(0)) at (prev + 115, 17) to (start + 0, 51)
+
+Function name: async::executor::block_on::VTABLE::{closure#2}
+Raw bytes (9): 0x[01, 01, 00, 01, 01, 74, 11, 00, 33]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 0
+Number of file 0 mappings: 1
+- Code(Counter(0)) at (prev + 116, 17) to (start + 0, 51)
+
+Function name: async::executor::block_on::VTABLE::{closure#3}
+Raw bytes (9): 0x[01, 01, 00, 01, 01, 75, 11, 00, 13]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 0
+Number of file 0 mappings: 1
+- Code(Counter(0)) at (prev + 117, 17) to (start + 0, 19)
+
+Function name: async::f
+Raw bytes (9): 0x[01, 01, 00, 01, 01, 11, 01, 00, 14]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 0
+Number of file 0 mappings: 1
+- Code(Counter(0)) at (prev + 17, 1) to (start + 0, 20)
+
+Function name: async::f::{closure#0}
+Raw bytes (9): 0x[01, 01, 00, 01, 01, 11, 14, 00, 19]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 0
+Number of file 0 mappings: 1
+- Code(Counter(0)) at (prev + 17, 20) to (start + 0, 25)
+
+Function name: async::foo (unused)
+Raw bytes (9): 0x[01, 01, 00, 01, 01, 13, 01, 00, 1e]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 0
+Number of file 0 mappings: 1
+- Code(Counter(0)) at (prev + 19, 1) to (start + 0, 30)
+
+Function name: async::foo::{closure#0} (unused)
+Raw bytes (9): 0x[01, 01, 00, 01, 01, 13, 1e, 00, 2d]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 0
+Number of file 0 mappings: 1
+- Code(Counter(0)) at (prev + 19, 30) to (start + 0, 45)
+
+Function name: async::g
+Raw bytes (9): 0x[01, 01, 00, 01, 01, 15, 01, 00, 17]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 0
+Number of file 0 mappings: 1
+- Code(Counter(0)) at (prev + 21, 1) to (start + 0, 23)
+
+Function name: async::g::{closure#0} (unused)
+Raw bytes (69): 0x[01, 01, 00, 0d, 00, 15, 17, 01, 0c, 00, 02, 09, 00, 0a, 01, 00, 0e, 00, 11, 00, 00, 12, 00, 17, 00, 00, 1b, 00, 1c, 00, 00, 20, 00, 22, 00, 01, 09, 00, 0a, 00, 00, 0e, 00, 11, 00, 00, 12, 00, 17, 00, 00, 1b, 00, 1c, 00, 00, 20, 00, 22, 00, 01, 0e, 00, 10, 00, 02, 01, 00, 02]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 0
+Number of file 0 mappings: 13
+- Code(Zero) at (prev + 21, 23) to (start + 1, 12)
+- Code(Zero) at (prev + 2, 9) to (start + 0, 10)
+- Code(Counter(0)) at (prev + 0, 14) to (start + 0, 17)
+- Code(Zero) at (prev + 0, 18) to (start + 0, 23)
+- Code(Zero) at (prev + 0, 27) to (start + 0, 28)
+- Code(Zero) at (prev + 0, 32) to (start + 0, 34)
+- Code(Zero) at (prev + 1, 9) to (start + 0, 10)
+- Code(Zero) at (prev + 0, 14) to (start + 0, 17)
+- Code(Zero) at (prev + 0, 18) to (start + 0, 23)
+- Code(Zero) at (prev + 0, 27) to (start + 0, 28)
+- Code(Zero) at (prev + 0, 32) to (start + 0, 34)
+- Code(Zero) at (prev + 1, 14) to (start + 0, 16)
+- Code(Zero) at (prev + 2, 1) to (start + 0, 2)
+
+Function name: async::h
+Raw bytes (9): 0x[01, 01, 00, 01, 01, 1d, 01, 00, 16]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 0
+Number of file 0 mappings: 1
+- Code(Counter(0)) at (prev + 29, 1) to (start + 0, 22)
+
+Function name: async::h::{closure#0} (unused)
+Raw bytes (44): 0x[01, 01, 00, 08, 00, 1d, 16, 03, 0c, 00, 04, 09, 00, 0a, 01, 00, 0e, 00, 13, 00, 00, 14, 00, 19, 00, 00, 1a, 00, 1b, 00, 00, 20, 00, 22, 00, 01, 0e, 00, 10, 00, 02, 01, 00, 02]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 0
+Number of file 0 mappings: 8
+- Code(Zero) at (prev + 29, 22) to (start + 3, 12)
+- Code(Zero) at (prev + 4, 9) to (start + 0, 10)
+- Code(Counter(0)) at (prev + 0, 14) to (start + 0, 19)
+- Code(Zero) at (prev + 0, 20) to (start + 0, 25)
+- Code(Zero) at (prev + 0, 26) to (start + 0, 27)
+- Code(Zero) at (prev + 0, 32) to (start + 0, 34)
+- Code(Zero) at (prev + 1, 14) to (start + 0, 16)
+- Code(Zero) at (prev + 2, 1) to (start + 0, 2)
+
+Function name: async::i
+Raw bytes (9): 0x[01, 01, 00, 01, 01, 26, 01, 00, 13]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 0
+Number of file 0 mappings: 1
+- Code(Counter(0)) at (prev + 38, 1) to (start + 0, 19)
+
+Function name: async::i::{closure#0}
+Raw bytes (84): 0x[01, 01, 05, 01, 00, 0d, 00, 1d, 00, 19, 13, 1d, 21, 0e, 01, 26, 13, 04, 0c, 0d, 05, 09, 00, 0a, 03, 00, 0e, 00, 12, 05, 00, 13, 00, 18, 09, 00, 1c, 00, 21, 07, 00, 27, 00, 2a, 15, 00, 2b, 00, 30, 1d, 01, 09, 00, 0a, 11, 00, 0e, 00, 11, 25, 00, 12, 00, 17, 29, 00, 1b, 00, 20, 0b, 00, 24, 00, 26, 21, 01, 0e, 00, 10, 0f, 02, 01, 00, 02]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 5
+- expression 0 operands: lhs = Counter(0), rhs = Zero
+- expression 1 operands: lhs = Counter(3), rhs = Zero
+- expression 2 operands: lhs = Counter(7), rhs = Zero
+- expression 3 operands: lhs = Counter(6), rhs = Expression(4, Add)
+- expression 4 operands: lhs = Counter(7), rhs = Counter(8)
+Number of file 0 mappings: 14
+- Code(Counter(0)) at (prev + 38, 19) to (start + 4, 12)
+- Code(Counter(3)) at (prev + 5, 9) to (start + 0, 10)
+- Code(Expression(0, Add)) at (prev + 0, 14) to (start + 0, 18)
+    = (c0 + Zero)
+- Code(Counter(1)) at (prev + 0, 19) to (start + 0, 24)
+- Code(Counter(2)) at (prev + 0, 28) to (start + 0, 33)
+- Code(Expression(1, Add)) at (prev + 0, 39) to (start + 0, 42)
+    = (c3 + Zero)
+- Code(Counter(5)) at (prev + 0, 43) to (start + 0, 48)
+- Code(Counter(7)) at (prev + 1, 9) to (start + 0, 10)
+- Code(Counter(4)) at (prev + 0, 14) to (start + 0, 17)
+- Code(Counter(9)) at (prev + 0, 18) to (start + 0, 23)
+- Code(Counter(10)) at (prev + 0, 27) to (start + 0, 32)
+- Code(Expression(2, Add)) at (prev + 0, 36) to (start + 0, 38)
+    = (c7 + Zero)
+- Code(Counter(8)) at (prev + 1, 14) to (start + 0, 16)
+- Code(Expression(3, Add)) at (prev + 2, 1) to (start + 0, 2)
+    = (c6 + (c7 + c8))
+
+Function name: async::j
+Raw bytes (59): 0x[01, 01, 05, 01, 00, 05, 00, 09, 00, 05, 13, 09, 0d, 09, 01, 31, 01, 13, 0c, 05, 14, 09, 00, 0a, 03, 00, 0e, 00, 1b, 07, 00, 1f, 00, 27, 09, 01, 09, 00, 0a, 11, 00, 0e, 00, 1a, 0b, 00, 1e, 00, 20, 0d, 01, 0e, 00, 10, 0f, 02, 01, 00, 02]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 5
+- expression 0 operands: lhs = Counter(0), rhs = Zero
+- expression 1 operands: lhs = Counter(1), rhs = Zero
+- expression 2 operands: lhs = Counter(2), rhs = Zero
+- expression 3 operands: lhs = Counter(1), rhs = Expression(4, Add)
+- expression 4 operands: lhs = Counter(2), rhs = Counter(3)
+Number of file 0 mappings: 9
+- Code(Counter(0)) at (prev + 49, 1) to (start + 19, 12)
+- Code(Counter(1)) at (prev + 20, 9) to (start + 0, 10)
+- Code(Expression(0, Add)) at (prev + 0, 14) to (start + 0, 27)
+    = (c0 + Zero)
+- Code(Expression(1, Add)) at (prev + 0, 31) to (start + 0, 39)
+    = (c1 + Zero)
+- Code(Counter(2)) at (prev + 1, 9) to (start + 0, 10)
+- Code(Counter(4)) at (prev + 0, 14) to (start + 0, 26)
+- Code(Expression(2, Add)) at (prev + 0, 30) to (start + 0, 32)
+    = (c2 + Zero)
+- Code(Counter(3)) at (prev + 1, 14) to (start + 0, 16)
+- Code(Expression(3, Add)) at (prev + 2, 1) to (start + 0, 2)
+    = (c1 + (c2 + c3))
+
+Function name: async::j::c
+Raw bytes (28): 0x[01, 01, 02, 01, 05, 05, 02, 04, 01, 33, 05, 01, 12, 05, 02, 0d, 00, 0e, 02, 0a, 0d, 00, 0e, 07, 02, 05, 00, 06]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 2
+- expression 0 operands: lhs = Counter(0), rhs = Counter(1)
+- expression 1 operands: lhs = Counter(1), rhs = Expression(0, Sub)
+Number of file 0 mappings: 4
+- Code(Counter(0)) at (prev + 51, 5) to (start + 1, 18)
+- Code(Counter(1)) at (prev + 2, 13) to (start + 0, 14)
+- Code(Expression(0, Sub)) at (prev + 10, 13) to (start + 0, 14)
+    = (c0 - c1)
+- Code(Expression(1, Add)) at (prev + 2, 5) to (start + 0, 6)
+    = (c1 + (c0 - c1))
+
+Function name: async::j::d
+Raw bytes (9): 0x[01, 01, 00, 01, 01, 42, 05, 00, 17]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 0
+Number of file 0 mappings: 1
+- Code(Counter(0)) at (prev + 66, 5) to (start + 0, 23)
+
+Function name: async::j::f
+Raw bytes (9): 0x[01, 01, 00, 01, 01, 43, 05, 00, 17]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 0
+Number of file 0 mappings: 1
+- Code(Counter(0)) at (prev + 67, 5) to (start + 0, 23)
+
+Function name: async::k (unused)
+Raw bytes (29): 0x[01, 01, 00, 05, 01, 4b, 01, 01, 0c, 00, 02, 0e, 00, 10, 00, 01, 0e, 00, 10, 00, 01, 0e, 00, 10, 00, 02, 01, 00, 02]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 0
+Number of file 0 mappings: 5
+- Code(Counter(0)) at (prev + 75, 1) to (start + 1, 12)
+- Code(Zero) at (prev + 2, 14) to (start + 0, 16)
+- Code(Zero) at (prev + 1, 14) to (start + 0, 16)
+- Code(Zero) at (prev + 1, 14) to (start + 0, 16)
+- Code(Zero) at (prev + 2, 1) to (start + 0, 2)
+
+Function name: async::l
+Raw bytes (37): 0x[01, 01, 04, 01, 07, 09, 05, 09, 0f, 05, 02, 05, 01, 53, 01, 01, 0c, 02, 02, 0e, 00, 10, 05, 01, 0e, 00, 10, 09, 01, 0e, 00, 10, 0b, 02, 01, 00, 02]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 4
+- expression 0 operands: lhs = Counter(0), rhs = Expression(1, Add)
+- expression 1 operands: lhs = Counter(2), rhs = Counter(1)
+- expression 2 operands: lhs = Counter(2), rhs = Expression(3, Add)
+- expression 3 operands: lhs = Counter(1), rhs = Expression(0, Sub)
+Number of file 0 mappings: 5
+- Code(Counter(0)) at (prev + 83, 1) to (start + 1, 12)
+- Code(Expression(0, Sub)) at (prev + 2, 14) to (start + 0, 16)
+    = (c0 - (c2 + c1))
+- Code(Counter(1)) at (prev + 1, 14) to (start + 0, 16)
+- Code(Counter(2)) at (prev + 1, 14) to (start + 0, 16)
+- Code(Expression(2, Add)) at (prev + 2, 1) to (start + 0, 2)
+    = (c2 + (c1 + (c0 - (c2 + c1))))
+
+Function name: async::m
+Raw bytes (9): 0x[01, 01, 00, 01, 01, 5b, 01, 00, 19]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 0
+Number of file 0 mappings: 1
+- Code(Counter(0)) at (prev + 91, 1) to (start + 0, 25)
+
+Function name: async::m::{closure#0} (unused)
+Raw bytes (9): 0x[01, 01, 00, 01, 01, 5b, 19, 00, 22]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 0
+Number of file 0 mappings: 1
+- Code(Counter(0)) at (prev + 91, 25) to (start + 0, 34)
+
+Function name: async::main
+Raw bytes (9): 0x[01, 01, 00, 01, 01, 5d, 01, 08, 02]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 0
+Number of file 0 mappings: 1
+- Code(Counter(0)) at (prev + 93, 1) to (start + 8, 2)
+

tests/coverage-map/status-quo/async.rs

@@ -0,0 +1,128 @@
+#![allow(unused_assignments, dead_code)]
+
+// compile-flags: --edition=2018 -C opt-level=1
+
+async fn c(x: u8) -> u8 {
+    if x == 8 {
+        1
+    } else {
+        0
+    }
+}
+
+async fn d() -> u8 { 1 }
+
+async fn e() -> u8 { 1 } // unused function; executor does not block on `g()`
+
+async fn f() -> u8 { 1 }
+
+async fn foo() -> [bool; 10] { [false; 10] } // unused function; executor does not block on `h()`
+
+pub async fn g(x: u8) {
+    match x {
+        y if e().await == y => (),
+        y if f().await == y => (),
+        _ => (),
+    }
+}
+
+async fn h(x: usize) { // The function signature is counted when called, but the body is not
+                       // executed (not awaited) so the open brace has a `0` count (at least when
+                       // displayed with `llvm-cov show` in color-mode).
+    match x {
+        y if foo().await[y] => (),
+        _ => (),
+    }
+}
+
+async fn i(x: u8) { // line coverage is 1, but there are 2 regions:
+                    // (a) the function signature, counted when the function is called; and
+                    // (b) the open brace for the function body, counted once when the body is
+                    // executed asynchronously.
+    match x {
+        y if c(x).await == y + 1 => { d().await; }
+        y if f().await == y + 1 => (),
+        _ => (),
+    }
+}
+
+fn j(x: u8) {
+    // non-async versions of `c()`, `d()`, and `f()` to make it similar to async `i()`.
+    fn c(x: u8) -> u8 {
+        if x == 8 {
+            1 // This line appears covered, but the 1-character expression span covering the `1`
+              // is not executed. (`llvm-cov show` displays a `^0` below the `1` ). This is because
+              // `fn j()` executes the open brace for the function body, followed by the function's
+              // first executable statement, `match x`. Inner function declarations are not
+              // "visible" to the MIR for `j()`, so the code region counts all lines between the
+              // open brace and the first statement as executed, which is, in a sense, true.
+              // `llvm-cov show` overcomes this kind of situation by showing the actual counts
+              // of the enclosed coverages, (that is, the `1` expression was not executed, and
+              // accurately displays a `0`).
+        } else {
+            0
+        }
+    }
+    fn d() -> u8 { 1 } // inner function is defined in-line, but the function is not executed
+    fn f() -> u8 { 1 }
+    match x {
+        y if c(x) == y + 1 => { d(); }
+        y if f() == y + 1 => (),
+        _ => (),
+    }
+}
+
+fn k(x: u8) { // unused function
+    match x {
+        1 => (),
+        2 => (),
+        _ => (),
+    }
+}
+
+fn l(x: u8) {
+    match x {
+        1 => (),
+        2 => (),
+        _ => (),
+    }
+}
+
+async fn m(x: u8) -> u8 { x - 1 }
+
+fn main() {
+    let _ = g(10);
+    let _ = h(9);
+    let mut future = Box::pin(i(8));
+    j(7);
+    l(6);
+    let _ = m(5);
+    executor::block_on(future.as_mut());
+}
+
+mod executor {
+    use core::{
+        future::Future,
+        pin::Pin,
+        task::{Context, Poll, RawWaker, RawWakerVTable, Waker},
+    };
+
+    pub fn block_on<F: Future>(mut future: F) -> F::Output {
+        let mut future = unsafe { Pin::new_unchecked(&mut future) };
+        use std::hint::unreachable_unchecked;
+        static VTABLE: RawWakerVTable = RawWakerVTable::new(
+            |_| unsafe { unreachable_unchecked() }, // clone
+            |_| unsafe { unreachable_unchecked() }, // wake
+            |_| unsafe { unreachable_unchecked() }, // wake_by_ref
+            |_| (),
+        );
+        let waker = unsafe { Waker::from_raw(RawWaker::new(core::ptr::null(), &VTABLE)) };
+        let mut context = Context::from_waker(&waker);
+
+        loop {
+            if let Poll::Ready(val) = future.as_mut().poll(&mut context) {
+                break val;
+            }
+        }
+    }
+}

tests/coverage-map/status-quo/async2.cov-map

@@ -0,0 +1,136 @@
+Function name: async2::async_func
+Raw bytes (9): 0x[01, 01, 00, 01, 01, 0b, 01, 00, 17]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 0
+Number of file 0 mappings: 1
+- Code(Counter(0)) at (prev + 11, 1) to (start + 0, 23)
+
+Function name: async2::async_func::{closure#0}
+Raw bytes (28): 0x[01, 01, 02, 01, 05, 05, 02, 04, 01, 0b, 17, 03, 09, 05, 03, 0a, 02, 06, 02, 02, 06, 00, 07, 07, 01, 01, 00, 02]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 2
+- expression 0 operands: lhs = Counter(0), rhs = Counter(1)
+- expression 1 operands: lhs = Counter(1), rhs = Expression(0, Sub)
+Number of file 0 mappings: 4
+- Code(Counter(0)) at (prev + 11, 23) to (start + 3, 9)
+- Code(Counter(1)) at (prev + 3, 10) to (start + 2, 6)
+- Code(Expression(0, Sub)) at (prev + 2, 6) to (start + 0, 7)
+    = (c0 - c1)
+- Code(Expression(1, Add)) at (prev + 1, 1) to (start + 0, 2)
+    = (c1 + (c0 - c1))
+
+Function name: async2::async_func_just_println
+Raw bytes (9): 0x[01, 01, 00, 01, 01, 13, 01, 00, 24]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 0
+Number of file 0 mappings: 1
+- Code(Counter(0)) at (prev + 19, 1) to (start + 0, 36)
+
+Function name: async2::async_func_just_println::{closure#0}
+Raw bytes (9): 0x[01, 01, 00, 01, 01, 13, 24, 02, 02]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 0
+Number of file 0 mappings: 1
+- Code(Counter(0)) at (prev + 19, 36) to (start + 2, 2)
+
+Function name: async2::executor::block_on::<async2::async_func::{closure#0}>
+Raw bytes (44): 0x[01, 01, 05, 0b, 05, 01, 05, 01, 05, 02, 00, 02, 00, 06, 01, 27, 05, 0a, 36, 02, 0d, 20, 00, 23, 0b, 00, 27, 00, 49, 0f, 01, 17, 00, 1a, 05, 01, 0e, 00, 0f, 13, 02, 05, 00, 06]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 5
+- expression 0 operands: lhs = Expression(2, Add), rhs = Counter(1)
+- expression 1 operands: lhs = Counter(0), rhs = Counter(1)
+- expression 2 operands: lhs = Counter(0), rhs = Counter(1)
+- expression 3 operands: lhs = Expression(0, Sub), rhs = Zero
+- expression 4 operands: lhs = Expression(0, Sub), rhs = Zero
+Number of file 0 mappings: 6
+- Code(Counter(0)) at (prev + 39, 5) to (start + 10, 54)
+- Code(Expression(0, Sub)) at (prev + 13, 32) to (start + 0, 35)
+    = ((c0 + c1) - c1)
+- Code(Expression(2, Add)) at (prev + 0, 39) to (start + 0, 73)
+    = (c0 + c1)
+- Code(Expression(3, Add)) at (prev + 1, 23) to (start + 0, 26)
+    = (((c0 + c1) - c1) + Zero)
+- Code(Counter(1)) at (prev + 1, 14) to (start + 0, 15)
+- Code(Expression(4, Add)) at (prev + 2, 5) to (start + 0, 6)
+    = (((c0 + c1) - c1) + Zero)
+
+Function name: async2::executor::block_on::<async2::async_func_just_println::{closure#0}>
+Raw bytes (44): 0x[01, 01, 05, 0b, 05, 01, 05, 01, 05, 02, 00, 02, 00, 06, 01, 27, 05, 0a, 36, 02, 0d, 20, 00, 23, 0b, 00, 27, 00, 49, 0f, 01, 17, 00, 1a, 05, 01, 0e, 00, 0f, 13, 02, 05, 00, 06]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 5
+- expression 0 operands: lhs = Expression(2, Add), rhs = Counter(1)
+- expression 1 operands: lhs = Counter(0), rhs = Counter(1)
+- expression 2 operands: lhs = Counter(0), rhs = Counter(1)
+- expression 3 operands: lhs = Expression(0, Sub), rhs = Zero
+- expression 4 operands: lhs = Expression(0, Sub), rhs = Zero
+Number of file 0 mappings: 6
+- Code(Counter(0)) at (prev + 39, 5) to (start + 10, 54)
+- Code(Expression(0, Sub)) at (prev + 13, 32) to (start + 0, 35)
+    = ((c0 + c1) - c1)
+- Code(Expression(2, Add)) at (prev + 0, 39) to (start + 0, 73)
+    = (c0 + c1)
+- Code(Expression(3, Add)) at (prev + 1, 23) to (start + 0, 26)
+    = (((c0 + c1) - c1) + Zero)
+- Code(Counter(1)) at (prev + 1, 14) to (start + 0, 15)
+- Code(Expression(4, Add)) at (prev + 2, 5) to (start + 0, 6)
+    = (((c0 + c1) - c1) + Zero)
+
+Function name: async2::executor::block_on::VTABLE::{closure#0}
+Raw bytes (9): 0x[01, 01, 00, 01, 01, 2b, 11, 00, 33]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 0
+Number of file 0 mappings: 1
+- Code(Counter(0)) at (prev + 43, 17) to (start + 0, 51)
+
+Function name: async2::executor::block_on::VTABLE::{closure#1}
+Raw bytes (9): 0x[01, 01, 00, 01, 01, 2c, 11, 00, 33]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 0
+Number of file 0 mappings: 1
+- Code(Counter(0)) at (prev + 44, 17) to (start + 0, 51)
+
+Function name: async2::executor::block_on::VTABLE::{closure#2}
+Raw bytes (9): 0x[01, 01, 00, 01, 01, 2d, 11, 00, 33]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 0
+Number of file 0 mappings: 1
+- Code(Counter(0)) at (prev + 45, 17) to (start + 0, 51)
+
+Function name: async2::executor::block_on::VTABLE::{closure#3}
+Raw bytes (9): 0x[01, 01, 00, 01, 01, 2e, 11, 00, 13]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 0
+Number of file 0 mappings: 1
+- Code(Counter(0)) at (prev + 46, 17) to (start + 0, 19)
+
+Function name: async2::main
+Raw bytes (9): 0x[01, 01, 00, 01, 01, 17, 01, 07, 02]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 0
+Number of file 0 mappings: 1
+- Code(Counter(0)) at (prev + 23, 1) to (start + 7, 2)
+
+Function name: async2::non_async_func
+Raw bytes (26): 0x[01, 01, 01, 05, 00, 04, 01, 03, 01, 03, 09, 05, 03, 0a, 02, 06, 00, 02, 06, 00, 07, 03, 01, 01, 00, 02]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 1
+- expression 0 operands: lhs = Counter(1), rhs = Zero
+Number of file 0 mappings: 4
+- Code(Counter(0)) at (prev + 3, 1) to (start + 3, 9)
+- Code(Counter(1)) at (prev + 3, 10) to (start + 2, 6)
+- Code(Zero) at (prev + 2, 6) to (start + 0, 7)
+- Code(Expression(0, Add)) at (prev + 1, 1) to (start + 0, 2)
+    = (c1 + Zero)
+

tests/coverage-map/status-quo/async2.rs

@@ -0,0 +1,57 @@
+// compile-flags: --edition=2018
+
+fn non_async_func() {
+    println!("non_async_func was covered");
+    let b = true;
+    if b {
+        println!("non_async_func println in block");
+    }
+}
+
+async fn async_func() {
+    println!("async_func was covered");
+    let b = true;
+    if b {
+        println!("async_func println in block");
+    }
+}
+
+async fn async_func_just_println() {
+    println!("async_func_just_println was covered");
+}
+
+fn main() {
+    println!("codecovsample::main");
+
+    non_async_func();
+
+    executor::block_on(async_func());
+    executor::block_on(async_func_just_println());
+}
+
+mod executor {
+    use core::{
+        future::Future,
+        pin::Pin,
+        task::{Context, Poll, RawWaker, RawWakerVTable, Waker},
+    };
+
+    pub fn block_on<F: Future>(mut future: F) -> F::Output {
+        let mut future = unsafe { Pin::new_unchecked(&mut future) };
+        use std::hint::unreachable_unchecked;
+        static VTABLE: RawWakerVTable = RawWakerVTable::new(
+            |_| unsafe { unreachable_unchecked() }, // clone
+            |_| unsafe { unreachable_unchecked() }, // wake
+            |_| unsafe { unreachable_unchecked() }, // wake_by_ref
+            |_| (),
+        );
+        let waker = unsafe { Waker::from_raw(RawWaker::new(core::ptr::null(), &VTABLE)) };
+        let mut context = Context::from_waker(&waker);
+
+        loop {
+            if let Poll::Ready(val) = future.as_mut().poll(&mut context) {
+                break val;
+            }
+        }
+    }
+}

tests/coverage-map/status-quo/closure.cov-map

@@ -0,0 +1,324 @@
+Function name: closure::main
+Raw bytes (170): 0x[01, 01, 17, 01, 00, 01, 00, 01, 00, 01, 00, 01, 00, 01, 00, 01, 00, 01, 00, 01, 00, 01, 00, 01, 00, 01, 00, 01, 00, 01, 00, 01, 00, 01, 00, 01, 00, 01, 00, 01, 00, 01, 00, 01, 05, 05, 5a, 01, 05, 18, 01, 08, 01, 0f, 0d, 03, 16, 0e, 06, 0a, 07, 10, 05, 13, 0d, 0b, 1a, 0e, 08, 09, 0f, 10, 05, 0e, 09, 13, 16, 05, 0d, 18, 17, 19, 09, 01, 21, 1b, 04, 09, 00, 29, 1f, 01, 09, 00, 2d, 23, 01, 09, 00, 24, 27, 05, 09, 00, 24, 2b, 02, 09, 00, 21, 2f, 04, 09, 00, 21, 33, 04, 09, 00, 28, 37, 09, 09, 00, 32, 3b, 04, 09, 00, 33, 3f, 07, 09, 00, 4b, 43, 08, 09, 01, 09, 47, 0a, 09, 01, 09, 4b, 08, 09, 01, 09, 4f, 0a, 08, 00, 10, 05, 00, 11, 04, 06, 5a, 04, 06, 00, 07, 57, 01, 05, 03, 02]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 23
+- expression 0 operands: lhs = Counter(0), rhs = Zero
+- expression 1 operands: lhs = Counter(0), rhs = Zero
+- expression 2 operands: lhs = Counter(0), rhs = Zero
+- expression 3 operands: lhs = Counter(0), rhs = Zero
+- expression 4 operands: lhs = Counter(0), rhs = Zero
+- expression 5 operands: lhs = Counter(0), rhs = Zero
+- expression 6 operands: lhs = Counter(0), rhs = Zero
+- expression 7 operands: lhs = Counter(0), rhs = Zero
+- expression 8 operands: lhs = Counter(0), rhs = Zero
+- expression 9 operands: lhs = Counter(0), rhs = Zero
+- expression 10 operands: lhs = Counter(0), rhs = Zero
+- expression 11 operands: lhs = Counter(0), rhs = Zero
+- expression 12 operands: lhs = Counter(0), rhs = Zero
+- expression 13 operands: lhs = Counter(0), rhs = Zero
+- expression 14 operands: lhs = Counter(0), rhs = Zero
+- expression 15 operands: lhs = Counter(0), rhs = Zero
+- expression 16 operands: lhs = Counter(0), rhs = Zero
+- expression 17 operands: lhs = Counter(0), rhs = Zero
+- expression 18 operands: lhs = Counter(0), rhs = Zero
+- expression 19 operands: lhs = Counter(0), rhs = Zero
+- expression 20 operands: lhs = Counter(0), rhs = Counter(1)
+- expression 21 operands: lhs = Counter(1), rhs = Expression(22, Sub)
+- expression 22 operands: lhs = Counter(0), rhs = Counter(1)
+Number of file 0 mappings: 24
+- Code(Counter(0)) at (prev + 8, 1) to (start + 15, 13)
+- Code(Expression(0, Add)) at (prev + 22, 14) to (start + 6, 10)
+    = (c0 + Zero)
+- Code(Expression(1, Add)) at (prev + 16, 5) to (start + 19, 13)
+    = (c0 + Zero)
+- Code(Expression(2, Add)) at (prev + 26, 14) to (start + 8, 9)
+    = (c0 + Zero)
+- Code(Expression(3, Add)) at (prev + 16, 5) to (start + 14, 9)
+    = (c0 + Zero)
+- Code(Expression(4, Add)) at (prev + 22, 5) to (start + 13, 24)
+    = (c0 + Zero)
+- Code(Expression(5, Add)) at (prev + 25, 9) to (start + 1, 33)
+    = (c0 + Zero)
+- Code(Expression(6, Add)) at (prev + 4, 9) to (start + 0, 41)
+    = (c0 + Zero)
+- Code(Expression(7, Add)) at (prev + 1, 9) to (start + 0, 45)
+    = (c0 + Zero)
+- Code(Expression(8, Add)) at (prev + 1, 9) to (start + 0, 36)
+    = (c0 + Zero)
+- Code(Expression(9, Add)) at (prev + 5, 9) to (start + 0, 36)
+    = (c0 + Zero)
+- Code(Expression(10, Add)) at (prev + 2, 9) to (start + 0, 33)
+    = (c0 + Zero)
+- Code(Expression(11, Add)) at (prev + 4, 9) to (start + 0, 33)
+    = (c0 + Zero)
+- Code(Expression(12, Add)) at (prev + 4, 9) to (start + 0, 40)
+    = (c0 + Zero)
+- Code(Expression(13, Add)) at (prev + 9, 9) to (start + 0, 50)
+    = (c0 + Zero)
+- Code(Expression(14, Add)) at (prev + 4, 9) to (start + 0, 51)
+    = (c0 + Zero)
+- Code(Expression(15, Add)) at (prev + 7, 9) to (start + 0, 75)
+    = (c0 + Zero)
+- Code(Expression(16, Add)) at (prev + 8, 9) to (start + 1, 9)
+    = (c0 + Zero)
+- Code(Expression(17, Add)) at (prev + 10, 9) to (start + 1, 9)
+    = (c0 + Zero)
+- Code(Expression(18, Add)) at (prev + 8, 9) to (start + 1, 9)
+    = (c0 + Zero)
+- Code(Expression(19, Add)) at (prev + 10, 8) to (start + 0, 16)
+    = (c0 + Zero)
+- Code(Counter(1)) at (prev + 0, 17) to (start + 4, 6)
+- Code(Expression(22, Sub)) at (prev + 4, 6) to (start + 0, 7)
+    = (c0 - c1)
+- Code(Expression(21, Add)) at (prev + 1, 5) to (start + 3, 2)
+    = (c1 + (c0 - c1))
+
+Function name: closure::main::{closure#0}
+Raw bytes (28): 0x[01, 01, 02, 01, 05, 05, 02, 04, 01, 27, 05, 02, 14, 05, 02, 15, 02, 0a, 02, 02, 0a, 00, 0b, 07, 01, 09, 01, 06]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 2
+- expression 0 operands: lhs = Counter(0), rhs = Counter(1)
+- expression 1 operands: lhs = Counter(1), rhs = Expression(0, Sub)
+Number of file 0 mappings: 4
+- Code(Counter(0)) at (prev + 39, 5) to (start + 2, 20)
+- Code(Counter(1)) at (prev + 2, 21) to (start + 2, 10)
+- Code(Expression(0, Sub)) at (prev + 2, 10) to (start + 0, 11)
+    = (c0 - c1)
+- Code(Expression(1, Add)) at (prev + 1, 9) to (start + 1, 6)
+    = (c1 + (c0 - c1))
+
+Function name: closure::main::{closure#10} (unused)
+Raw bytes (10): 0x[01, 01, 00, 01, 01, 9a, 01, 07, 00, 21]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 0
+Number of file 0 mappings: 1
+- Code(Counter(0)) at (prev + 154, 7) to (start + 0, 33)
+
+Function name: closure::main::{closure#11} (unused)
+Raw bytes (10): 0x[01, 01, 00, 01, 01, 9e, 01, 07, 00, 21]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 0
+Number of file 0 mappings: 1
+- Code(Counter(0)) at (prev + 158, 7) to (start + 0, 33)
+
+Function name: closure::main::{closure#12} (unused)
+Raw bytes (10): 0x[01, 01, 00, 01, 01, a6, 01, 01, 00, 17]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 0
+Number of file 0 mappings: 1
+- Code(Counter(0)) at (prev + 166, 1) to (start + 0, 23)
+
+Function name: closure::main::{closure#13} (unused)
+Raw bytes (10): 0x[01, 01, 00, 01, 01, ab, 01, 0d, 02, 0e]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 0
+Number of file 0 mappings: 1
+- Code(Counter(0)) at (prev + 171, 13) to (start + 2, 14)
+
+Function name: closure::main::{closure#14}
+Raw bytes (38): 0x[01, 01, 04, 05, 0a, 01, 05, 01, 05, 03, 00, 05, 03, b2, 01, 0d, 00, 15, 01, 01, 11, 01, 1b, 05, 01, 1e, 00, 25, 0a, 00, 2f, 00, 33, 0f, 01, 0d, 00, 0e]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 4
+- expression 0 operands: lhs = Counter(1), rhs = Expression(2, Sub)
+- expression 1 operands: lhs = Counter(0), rhs = Counter(1)
+- expression 2 operands: lhs = Counter(0), rhs = Counter(1)
+- expression 3 operands: lhs = Expression(0, Add), rhs = Zero
+Number of file 0 mappings: 5
+- Code(Expression(0, Add)) at (prev + 178, 13) to (start + 0, 21)
+    = (c1 + (c0 - c1))
+- Code(Counter(0)) at (prev + 1, 17) to (start + 1, 27)
+- Code(Counter(1)) at (prev + 1, 30) to (start + 0, 37)
+- Code(Expression(2, Sub)) at (prev + 0, 47) to (start + 0, 51)
+    = (c0 - c1)
+- Code(Expression(3, Add)) at (prev + 1, 13) to (start + 0, 14)
+    = ((c1 + (c0 - c1)) + Zero)
+
+Function name: closure::main::{closure#15}
+Raw bytes (45): 0x[01, 01, 05, 05, 0e, 01, 05, 01, 00, 01, 05, 03, 00, 06, 01, ba, 01, 09, 00, 0a, 03, 01, 0d, 00, 15, 0b, 01, 11, 01, 1b, 05, 01, 1e, 00, 25, 0e, 00, 2f, 00, 33, 13, 02, 09, 00, 0a]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 5
+- expression 0 operands: lhs = Counter(1), rhs = Expression(3, Sub)
+- expression 1 operands: lhs = Counter(0), rhs = Counter(1)
+- expression 2 operands: lhs = Counter(0), rhs = Zero
+- expression 3 operands: lhs = Counter(0), rhs = Counter(1)
+- expression 4 operands: lhs = Expression(0, Add), rhs = Zero
+Number of file 0 mappings: 6
+- Code(Counter(0)) at (prev + 186, 9) to (start + 0, 10)
+- Code(Expression(0, Add)) at (prev + 1, 13) to (start + 0, 21)
+    = (c1 + (c0 - c1))
+- Code(Expression(2, Add)) at (prev + 1, 17) to (start + 1, 27)
+    = (c0 + Zero)
+- Code(Counter(1)) at (prev + 1, 30) to (start + 0, 37)
+- Code(Expression(3, Sub)) at (prev + 0, 47) to (start + 0, 51)
+    = (c0 - c1)
+- Code(Expression(4, Add)) at (prev + 2, 9) to (start + 0, 10)
+    = ((c1 + (c0 - c1)) + Zero)
+
+Function name: closure::main::{closure#16}
+Raw bytes (38): 0x[01, 01, 04, 05, 0a, 01, 05, 01, 05, 03, 00, 05, 03, c4, 01, 0d, 00, 15, 01, 01, 11, 01, 1b, 05, 01, 1e, 00, 25, 0a, 00, 2f, 00, 33, 0f, 01, 0d, 00, 0e]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 4
+- expression 0 operands: lhs = Counter(1), rhs = Expression(2, Sub)
+- expression 1 operands: lhs = Counter(0), rhs = Counter(1)
+- expression 2 operands: lhs = Counter(0), rhs = Counter(1)
+- expression 3 operands: lhs = Expression(0, Add), rhs = Zero
+Number of file 0 mappings: 5
+- Code(Expression(0, Add)) at (prev + 196, 13) to (start + 0, 21)
+    = (c1 + (c0 - c1))
+- Code(Counter(0)) at (prev + 1, 17) to (start + 1, 27)
+- Code(Counter(1)) at (prev + 1, 30) to (start + 0, 37)
+- Code(Expression(2, Sub)) at (prev + 0, 47) to (start + 0, 51)
+    = (c0 - c1)
+- Code(Expression(3, Add)) at (prev + 1, 13) to (start + 0, 14)
+    = ((c1 + (c0 - c1)) + Zero)
+
+Function name: closure::main::{closure#17}
+Raw bytes (45): 0x[01, 01, 05, 05, 0e, 01, 05, 01, 00, 01, 05, 03, 00, 06, 01, cc, 01, 09, 00, 0a, 03, 01, 0d, 00, 15, 0b, 01, 11, 01, 1b, 05, 01, 1e, 00, 25, 0e, 00, 2f, 00, 33, 13, 02, 09, 00, 0a]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 5
+- expression 0 operands: lhs = Counter(1), rhs = Expression(3, Sub)
+- expression 1 operands: lhs = Counter(0), rhs = Counter(1)
+- expression 2 operands: lhs = Counter(0), rhs = Zero
+- expression 3 operands: lhs = Counter(0), rhs = Counter(1)
+- expression 4 operands: lhs = Expression(0, Add), rhs = Zero
+Number of file 0 mappings: 6
+- Code(Counter(0)) at (prev + 204, 9) to (start + 0, 10)
+- Code(Expression(0, Add)) at (prev + 1, 13) to (start + 0, 21)
+    = (c1 + (c0 - c1))
+- Code(Expression(2, Add)) at (prev + 1, 17) to (start + 1, 27)
+    = (c0 + Zero)
+- Code(Counter(1)) at (prev + 1, 30) to (start + 0, 37)
+- Code(Expression(3, Sub)) at (prev + 0, 47) to (start + 0, 51)
+    = (c0 - c1)
+- Code(Expression(4, Add)) at (prev + 2, 9) to (start + 0, 10)
+    = ((c1 + (c0 - c1)) + Zero)
+
+Function name: closure::main::{closure#18}
+Raw bytes (28): 0x[01, 01, 02, 01, 05, 05, 02, 04, 01, 18, 0d, 02, 1c, 05, 02, 1d, 02, 12, 02, 02, 12, 00, 13, 07, 01, 11, 01, 0e]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 2
+- expression 0 operands: lhs = Counter(0), rhs = Counter(1)
+- expression 1 operands: lhs = Counter(1), rhs = Expression(0, Sub)
+Number of file 0 mappings: 4
+- Code(Counter(0)) at (prev + 24, 13) to (start + 2, 28)
+- Code(Counter(1)) at (prev + 2, 29) to (start + 2, 18)
+- Code(Expression(0, Sub)) at (prev + 2, 18) to (start + 0, 19)
+    = (c0 - c1)
+- Code(Expression(1, Add)) at (prev + 1, 17) to (start + 1, 14)
+    = (c1 + (c0 - c1))
+
+Function name: closure::main::{closure#19}
+Raw bytes (28): 0x[01, 01, 02, 01, 05, 05, 02, 04, 01, 42, 0d, 02, 1c, 05, 02, 1d, 02, 12, 02, 02, 12, 00, 13, 07, 01, 11, 01, 0e]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 2
+- expression 0 operands: lhs = Counter(0), rhs = Counter(1)
+- expression 1 operands: lhs = Counter(1), rhs = Expression(0, Sub)
+Number of file 0 mappings: 4
+- Code(Counter(0)) at (prev + 66, 13) to (start + 2, 28)
+- Code(Counter(1)) at (prev + 2, 29) to (start + 2, 18)
+- Code(Expression(0, Sub)) at (prev + 2, 18) to (start + 0, 19)
+    = (c0 - c1)
+- Code(Expression(1, Add)) at (prev + 1, 17) to (start + 1, 14)
+    = (c1 + (c0 - c1))
+
+Function name: closure::main::{closure#1}
+Raw bytes (28): 0x[01, 01, 02, 01, 05, 05, 02, 04, 01, 51, 05, 02, 14, 05, 02, 15, 02, 0a, 02, 02, 0a, 00, 0b, 07, 01, 09, 01, 06]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 2
+- expression 0 operands: lhs = Counter(0), rhs = Counter(1)
+- expression 1 operands: lhs = Counter(1), rhs = Expression(0, Sub)
+Number of file 0 mappings: 4
+- Code(Counter(0)) at (prev + 81, 5) to (start + 2, 20)
+- Code(Counter(1)) at (prev + 2, 21) to (start + 2, 10)
+- Code(Expression(0, Sub)) at (prev + 2, 10) to (start + 0, 11)
+    = (c0 - c1)
+- Code(Expression(1, Add)) at (prev + 1, 9) to (start + 1, 6)
+    = (c1 + (c0 - c1))
+
+Function name: closure::main::{closure#2}
+Raw bytes (28): 0x[01, 01, 02, 01, 05, 05, 02, 04, 01, 67, 05, 02, 14, 05, 02, 15, 02, 0a, 02, 02, 0a, 00, 0b, 07, 01, 09, 01, 06]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 2
+- expression 0 operands: lhs = Counter(0), rhs = Counter(1)
+- expression 1 operands: lhs = Counter(1), rhs = Expression(0, Sub)
+Number of file 0 mappings: 4
+- Code(Counter(0)) at (prev + 103, 5) to (start + 2, 20)
+- Code(Counter(1)) at (prev + 2, 21) to (start + 2, 10)
+- Code(Expression(0, Sub)) at (prev + 2, 10) to (start + 0, 11)
+    = (c0 - c1)
+- Code(Expression(1, Add)) at (prev + 1, 9) to (start + 1, 6)
+    = (c1 + (c0 - c1))
+
+Function name: closure::main::{closure#3} (unused)
+Raw bytes (25): 0x[01, 01, 00, 04, 01, 80, 01, 05, 01, 14, 00, 01, 15, 02, 0a, 00, 02, 0a, 00, 0b, 00, 01, 09, 01, 06]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 0
+Number of file 0 mappings: 4
+- Code(Counter(0)) at (prev + 128, 5) to (start + 1, 20)
+- Code(Zero) at (prev + 1, 21) to (start + 2, 10)
+- Code(Zero) at (prev + 2, 10) to (start + 0, 11)
+- Code(Zero) at (prev + 1, 9) to (start + 1, 6)
+
+Function name: closure::main::{closure#4} (unused)
+Raw bytes (10): 0x[01, 01, 00, 01, 01, 88, 01, 35, 00, 43]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 0
+Number of file 0 mappings: 1
+- Code(Counter(0)) at (prev + 136, 53) to (start + 0, 67)
+
+Function name: closure::main::{closure#5}
+Raw bytes (10): 0x[01, 01, 00, 01, 01, 8b, 01, 3d, 00, 4f]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 0
+Number of file 0 mappings: 1
+- Code(Counter(0)) at (prev + 139, 61) to (start + 0, 79)
+
+Function name: closure::main::{closure#6}
+Raw bytes (10): 0x[01, 01, 00, 01, 01, 8c, 01, 41, 00, 57]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 0
+Number of file 0 mappings: 1
+- Code(Counter(0)) at (prev + 140, 65) to (start + 0, 87)
+
+Function name: closure::main::{closure#7} (unused)
+Raw bytes (10): 0x[01, 01, 00, 01, 01, 8d, 01, 3b, 00, 51]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 0
+Number of file 0 mappings: 1
+- Code(Counter(0)) at (prev + 141, 59) to (start + 0, 81)
+
+Function name: closure::main::{closure#8} (unused)
+Raw bytes (10): 0x[01, 01, 00, 01, 01, 92, 01, 3b, 00, 55]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 0
+Number of file 0 mappings: 1
+- Code(Counter(0)) at (prev + 146, 59) to (start + 0, 85)
+
+Function name: closure::main::{closure#9} (unused)
+Raw bytes (10): 0x[01, 01, 00, 01, 01, 94, 01, 38, 02, 06]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 0
+Number of file 0 mappings: 1
+- Code(Counter(0)) at (prev + 148, 56) to (start + 2, 6)
+

tests/coverage-map/status-quo/closure.rs

@@ -0,0 +1,220 @@
+#![allow(unused_assignments, unused_variables)]
+// compile-flags: -C opt-level=2
+
+// This test used to be sensitive to certain coverage-specific hacks in
+// `rustc_middle/mir/mono.rs`, but those hacks were later cleaned up by
+// <https://github.com/rust-lang/rust/pull/83666>.
+
+fn main() {
+    // Initialize test constants in a way that cannot be determined at compile time, to ensure
+    // rustc and LLVM cannot optimize out statements (or coverage counters) downstream from
+    // dependent conditions.
+    let is_true = std::env::args().len() == 1;
+    let is_false = !is_true;
+
+    let mut some_string = Some(String::from("the string content"));
+    println!(
+        "The string or alt: {}"
+        ,
+        some_string
+            .
+            unwrap_or_else
+        (
+            ||
+            {
+                let mut countdown = 0;
+                if is_false {
+                    countdown = 10;
+                }
+                "alt string 1".to_owned()
+            }
+        )
+    );
+
+    some_string = Some(String::from("the string content"));
+    let
+        a
+    =
+        ||
+    {
+        let mut countdown = 0;
+        if is_false {
+            countdown = 10;
+        }
+        "alt string 2".to_owned()
+    };
+    println!(
+        "The string or alt: {}"
+        ,
+        some_string
+            .
+            unwrap_or_else
+        (
+            a
+        )
+    );
+
+    some_string = None;
+    println!(
+        "The string or alt: {}"
+        ,
+        some_string
+            .
+            unwrap_or_else
+        (
+            ||
+            {
+                let mut countdown = 0;
+                if is_false {
+                    countdown = 10;
+                }
+                "alt string 3".to_owned()
+            }
+        )
+    );
+
+    some_string = None;
+    let
+        a
+    =
+        ||
+    {
+        let mut countdown = 0;
+        if is_false {
+            countdown = 10;
+        }
+        "alt string 4".to_owned()
+    };
+    println!(
+        "The string or alt: {}"
+        ,
+        some_string
+            .
+            unwrap_or_else
+        (
+            a
+        )
+    );
+
+    let
+        quote_closure
+    =
+        |val|
+    {
+        let mut countdown = 0;
+        if is_false {
+            countdown = 10;
+        }
+        format!("'{}'", val)
+    };
+    println!(
+        "Repeated, quoted string: {:?}"
+        ,
+        std::iter::repeat("repeat me")
+            .take(5)
+            .map
+        (
+            quote_closure
+        )
+            .collect::<Vec<_>>()
+    );
+
+    let
+        _unused_closure
+    =
+        |
+            mut countdown
+        |
+    {
+        if is_false {
+            countdown = 10;
+        }
+        "closure should be unused".to_owned()
+    };
+
+    let mut countdown = 10;
+    let _short_unused_closure = | _unused_arg: u8 | countdown += 1;
+
+
+    let short_used_covered_closure_macro = | used_arg: u8 | println!("called");
+    let short_used_not_covered_closure_macro = | used_arg: u8 | println!("not called");
+    let _short_unused_closure_macro = | _unused_arg: u8 | println!("not called");
+
+
+
+
+    let _short_unused_closure_block = | _unused_arg: u8 | { println!("not called") };
+
+    let _shortish_unused_closure = | _unused_arg: u8 | {
+        println!("not called")
+    };
+
+    let _as_short_unused_closure = |
+        _unused_arg: u8
+    | { println!("not called") };
+
+    let _almost_as_short_unused_closure = |
+        _unused_arg: u8
+    | { println!("not called") }
+    ;
+
+
+
+
+
+    let _short_unused_closure_line_break_no_block = | _unused_arg: u8 |
+println!("not called")
+    ;
+
+    let _short_unused_closure_line_break_no_block2 =
+        | _unused_arg: u8 |
+            println!(
+                "not called"
+            )
+    ;
+
+    let short_used_not_covered_closure_line_break_no_block_embedded_branch =
+        | _unused_arg: u8 |
+            println!(
+                "not called: {}",
+                if is_true { "check" } else { "me" }
+            )
+    ;
+
+    let short_used_not_covered_closure_line_break_block_embedded_branch =
+        | _unused_arg: u8 |
+        {
+            println!(
+                "not called: {}",
+                if is_true { "check" } else { "me" }
+            )
+        }
+    ;
+
+    let short_used_covered_closure_line_break_no_block_embedded_branch =
+        | _unused_arg: u8 |
+            println!(
+                "not called: {}",
+                if is_true { "check" } else { "me" }
+            )
+    ;
+
+    let short_used_covered_closure_line_break_block_embedded_branch =
+        | _unused_arg: u8 |
+        {
+            println!(
+                "not called: {}",
+                if is_true { "check" } else { "me" }
+            )
+        }
+    ;
+
+    if is_false {
+        short_used_not_covered_closure_macro(0);
+        short_used_not_covered_closure_line_break_no_block_embedded_branch(0);
+        short_used_not_covered_closure_line_break_block_embedded_branch(0);
+    }
+    short_used_covered_closure_macro(0);
+    short_used_covered_closure_line_break_no_block_embedded_branch(0);
+    short_used_covered_closure_line_break_block_embedded_branch(0);
+}

tests/coverage-map/status-quo/closure_macro.cov-map

@@ -0,0 +1,40 @@
+Function name: closure_macro::load_configuration_files
+Raw bytes (9): 0x[01, 01, 00, 01, 01, 1d, 01, 02, 02]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 0
+Number of file 0 mappings: 1
+- Code(Counter(0)) at (prev + 29, 1) to (start + 2, 2)
+
+Function name: closure_macro::main
+Raw bytes (49): 0x[01, 01, 05, 01, 05, 02, 00, 05, 00, 02, 00, 05, 02, 07, 01, 21, 01, 01, 21, 02, 02, 09, 00, 0f, 05, 00, 12, 00, 13, 07, 00, 12, 00, 13, 0b, 00, 54, 00, 55, 0f, 02, 09, 02, 0b, 13, 03, 01, 00, 02]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 5
+- expression 0 operands: lhs = Counter(0), rhs = Counter(1)
+- expression 1 operands: lhs = Expression(0, Sub), rhs = Zero
+- expression 2 operands: lhs = Counter(1), rhs = Zero
+- expression 3 operands: lhs = Expression(0, Sub), rhs = Zero
+- expression 4 operands: lhs = Counter(1), rhs = Expression(0, Sub)
+Number of file 0 mappings: 7
+- Code(Counter(0)) at (prev + 33, 1) to (start + 1, 33)
+- Code(Expression(0, Sub)) at (prev + 2, 9) to (start + 0, 15)
+    = (c0 - c1)
+- Code(Counter(1)) at (prev + 0, 18) to (start + 0, 19)
+- Code(Expression(1, Add)) at (prev + 0, 18) to (start + 0, 19)
+    = ((c0 - c1) + Zero)
+- Code(Expression(2, Add)) at (prev + 0, 84) to (start + 0, 85)
+    = (c1 + Zero)
+- Code(Expression(3, Add)) at (prev + 2, 9) to (start + 2, 11)
+    = ((c0 - c1) + Zero)
+- Code(Expression(4, Add)) at (prev + 3, 1) to (start + 0, 2)
+    = (c1 + (c0 - c1))
+
+Function name: closure_macro::main::{closure#0}
+Raw bytes (9): 0x[01, 01, 00, 01, 01, 23, 12, 00, 54]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 0
+Number of file 0 mappings: 1
+- Code(Counter(0)) at (prev + 35, 18) to (start + 0, 84)
+

tests/coverage-map/status-quo/closure_macro.rs

@@ -0,0 +1,40 @@
+// compile-flags: --edition=2018
+#![feature(no_coverage)]
+
+macro_rules! bail {
+    ($msg:literal $(,)?) => {
+        if $msg.len() > 0 {
+            println!("no msg");
+        } else {
+            println!($msg);
+        }
+        return Err(String::from($msg));
+    };
+}
+
+macro_rules! on_error {
+    ($value:expr, $error_message:expr) => {
+        $value.or_else(|e| { // FIXME(85000): no coverage in closure macros
+            let message = format!($error_message, e);
+            if message.len() > 0 {
+                println!("{}", message);
+                Ok(String::from("ok"))
+            } else {
+                bail!("error");
+            }
+        })
+    };
+}
+
+fn load_configuration_files() -> Result<String, String> {
+    Ok(String::from("config"))
+}
+
+pub fn main() -> Result<(), String> {
+    println!("Starting service");
+    let config = on_error!(load_configuration_files(), "Error loading configs: {}")?;
+
+    let startup_delay_duration = String::from("arg");
+    let _ = (config, startup_delay_duration);
+    Ok(())
+}

tests/coverage-map/status-quo/closure_macro_async.cov-map

@@ -0,0 +1,48 @@
+Function name: closure_macro_async::load_configuration_files
+Raw bytes (9): 0x[01, 01, 00, 01, 01, 1d, 01, 02, 02]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 0
+Number of file 0 mappings: 1
+- Code(Counter(0)) at (prev + 29, 1) to (start + 2, 2)
+
+Function name: closure_macro_async::test
+Raw bytes (9): 0x[01, 01, 00, 01, 01, 21, 01, 00, 2b]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 0
+Number of file 0 mappings: 1
+- Code(Counter(0)) at (prev + 33, 1) to (start + 0, 43)
+
+Function name: closure_macro_async::test::{closure#0}
+Raw bytes (49): 0x[01, 01, 05, 01, 05, 02, 00, 05, 00, 02, 00, 05, 02, 07, 01, 21, 2b, 01, 21, 02, 02, 09, 00, 0f, 05, 00, 12, 00, 13, 07, 00, 12, 00, 13, 0b, 00, 54, 00, 55, 0f, 02, 09, 02, 0b, 13, 03, 01, 00, 02]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 5
+- expression 0 operands: lhs = Counter(0), rhs = Counter(1)
+- expression 1 operands: lhs = Expression(0, Sub), rhs = Zero
+- expression 2 operands: lhs = Counter(1), rhs = Zero
+- expression 3 operands: lhs = Expression(0, Sub), rhs = Zero
+- expression 4 operands: lhs = Counter(1), rhs = Expression(0, Sub)
+Number of file 0 mappings: 7
+- Code(Counter(0)) at (prev + 33, 43) to (start + 1, 33)
+- Code(Expression(0, Sub)) at (prev + 2, 9) to (start + 0, 15)
+    = (c0 - c1)
+- Code(Counter(1)) at (prev + 0, 18) to (start + 0, 19)
+- Code(Expression(1, Add)) at (prev + 0, 18) to (start + 0, 19)
+    = ((c0 - c1) + Zero)
+- Code(Expression(2, Add)) at (prev + 0, 84) to (start + 0, 85)
+    = (c1 + Zero)
+- Code(Expression(3, Add)) at (prev + 2, 9) to (start + 2, 11)
+    = ((c0 - c1) + Zero)
+- Code(Expression(4, Add)) at (prev + 3, 1) to (start + 0, 2)
+    = (c1 + (c0 - c1))
+
+Function name: closure_macro_async::test::{closure#0}::{closure#0}
+Raw bytes (9): 0x[01, 01, 00, 01, 01, 23, 12, 00, 54]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 0
+Number of file 0 mappings: 1
+- Code(Counter(0)) at (prev + 35, 18) to (start + 0, 84)
+

tests/coverage-map/status-quo/closure_macro_async.rs

@@ -0,0 +1,77 @@
+// compile-flags: --edition=2018
+#![feature(no_coverage)]
+
+macro_rules! bail {
+    ($msg:literal $(,)?) => {
+        if $msg.len() > 0 {
+            println!("no msg");
+        } else {
+            println!($msg);
+        }
+        return Err(String::from($msg));
+    };
+}
+
+macro_rules! on_error {
+    ($value:expr, $error_message:expr) => {
+        $value.or_else(|e| { // FIXME(85000): no coverage in closure macros
+            let message = format!($error_message, e);
+            if message.len() > 0 {
+                println!("{}", message);
+                Ok(String::from("ok"))
+            } else {
+                bail!("error");
+            }
+        })
+    };
+}
+
+fn load_configuration_files() -> Result<String, String> {
+    Ok(String::from("config"))
+}
+
+pub async fn test() -> Result<(), String> {
+    println!("Starting service");
+    let config = on_error!(load_configuration_files(), "Error loading configs: {}")?;
+
+    let startup_delay_duration = String::from("arg");
+    let _ = (config, startup_delay_duration);
+    Ok(())
+}
+
+#[no_coverage]
+fn main() {
+    executor::block_on(test()).unwrap();
+}
+
+mod executor {
+    use core::{
+        future::Future,
+        pin::Pin,
+        task::{Context, Poll, RawWaker, RawWakerVTable, Waker},
+    };
+
+    #[no_coverage]
+    pub fn block_on<F: Future>(mut future: F) -> F::Output {
+        let mut future = unsafe { Pin::new_unchecked(&mut future) };
+        use std::hint::unreachable_unchecked;
+        static VTABLE: RawWakerVTable = RawWakerVTable::new(
+            #[no_coverage]
+            |_| unsafe { unreachable_unchecked() }, // clone
+            #[no_coverage]
+            |_| unsafe { unreachable_unchecked() }, // wake
+            #[no_coverage]
+            |_| unsafe { unreachable_unchecked() }, // wake_by_ref
+            #[no_coverage]
+            |_| (),
+        );
+        let waker = unsafe { Waker::from_raw(RawWaker::new(core::ptr::null(), &VTABLE)) };
+        let mut context = Context::from_waker(&waker);
+
+        loop {
+            if let Poll::Ready(val) = future.as_mut().poll(&mut context) {
+                break val;
+            }
+        }
+    }
+}

tests/coverage-map/status-quo/conditions.cov-map

@@ -0,0 +1,261 @@
+Function name: conditions::main
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+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 144
+- expression 0 operands: lhs = Counter(2), rhs = Expression(12, Add)
+- expression 1 operands: lhs = Expression(13, Add), rhs = Counter(16)
+- expression 2 operands: lhs = Expression(14, Add), rhs = Counter(15)
+- expression 3 operands: lhs = Counter(13), rhs = Counter(14)
+- expression 4 operands: lhs = Counter(1), rhs = Zero
+- expression 5 operands: lhs = Expression(143, Add), rhs = Counter(2)
+- expression 6 operands: lhs = Counter(1), rhs = Zero
+- expression 7 operands: lhs = Counter(3), rhs = Counter(13)
+- expression 8 operands: lhs = Expression(9, Sub), rhs = Counter(14)
+- expression 9 operands: lhs = Counter(3), rhs = Counter(13)
+- expression 10 operands: lhs = Expression(14, Add), rhs = Counter(15)
+- expression 11 operands: lhs = Counter(13), rhs = Counter(14)
+- expression 12 operands: lhs = Expression(13, Add), rhs = Counter(16)
+- expression 13 operands: lhs = Expression(14, Add), rhs = Counter(15)
+- expression 14 operands: lhs = Counter(13), rhs = Counter(14)
+- expression 15 operands: lhs = Expression(142, Sub), rhs = Counter(3)
+- expression 16 operands: lhs = Expression(143, Add), rhs = Counter(2)
+- expression 17 operands: lhs = Counter(1), rhs = Zero
+- expression 18 operands: lhs = Expression(0, Add), rhs = Zero
+- expression 19 operands: lhs = Counter(17), rhs = Zero
+- expression 20 operands: lhs = Expression(33, Add), rhs = Counter(18)
+- expression 21 operands: lhs = Counter(17), rhs = Zero
+- expression 22 operands: lhs = Expression(32, Sub), rhs = Counter(12)
+- expression 23 operands: lhs = Expression(33, Add), rhs = Counter(18)
+- expression 24 operands: lhs = Counter(17), rhs = Zero
+- expression 25 operands: lhs = Expression(31, Sub), rhs = Counter(19)
+- expression 26 operands: lhs = Expression(32, Sub), rhs = Counter(12)
+- expression 27 operands: lhs = Expression(33, Add), rhs = Counter(18)
+- expression 28 operands: lhs = Counter(17), rhs = Zero
+- expression 29 operands: lhs = Expression(30, Sub), rhs = Counter(20)
+- expression 30 operands: lhs = Expression(31, Sub), rhs = Counter(19)
+- expression 31 operands: lhs = Expression(32, Sub), rhs = Counter(12)
+- expression 32 operands: lhs = Expression(33, Add), rhs = Counter(18)
+- expression 33 operands: lhs = Counter(17), rhs = Zero
+- expression 34 operands: lhs = Expression(42, Add), rhs = Counter(21)
+- expression 35 operands: lhs = Counter(19), rhs = Counter(20)
+- expression 36 operands: lhs = Expression(41, Add), rhs = Counter(22)
+- expression 37 operands: lhs = Expression(42, Add), rhs = Counter(21)
+- expression 38 operands: lhs = Counter(19), rhs = Counter(20)
+- expression 39 operands: lhs = Counter(18), rhs = Expression(40, Add)
+- expression 40 operands: lhs = Expression(41, Add), rhs = Counter(22)
+- expression 41 operands: lhs = Expression(42, Add), rhs = Counter(21)
+- expression 42 operands: lhs = Counter(19), rhs = Counter(20)
+- expression 43 operands: lhs = Counter(24), rhs = Zero
+- expression 44 operands: lhs = Expression(57, Add), rhs = Counter(25)
+- expression 45 operands: lhs = Counter(24), rhs = Zero
+- expression 46 operands: lhs = Expression(56, Sub), rhs = Counter(11)
+- expression 47 operands: lhs = Expression(57, Add), rhs = Counter(25)
+- expression 48 operands: lhs = Counter(24), rhs = Zero
+- expression 49 operands: lhs = Expression(55, Sub), rhs = Counter(26)
+- expression 50 operands: lhs = Expression(56, Sub), rhs = Counter(11)
+- expression 51 operands: lhs = Expression(57, Add), rhs = Counter(25)
+- expression 52 operands: lhs = Counter(24), rhs = Zero
+- expression 53 operands: lhs = Expression(54, Sub), rhs = Counter(27)
+- expression 54 operands: lhs = Expression(55, Sub), rhs = Counter(26)
+- expression 55 operands: lhs = Expression(56, Sub), rhs = Counter(11)
+- expression 56 operands: lhs = Expression(57, Add), rhs = Counter(25)
+- expression 57 operands: lhs = Counter(24), rhs = Zero
+- expression 58 operands: lhs = Expression(67, Add), rhs = Counter(28)
+- expression 59 operands: lhs = Counter(26), rhs = Counter(27)
+- expression 60 operands: lhs = Expression(66, Add), rhs = Counter(29)
+- expression 61 operands: lhs = Expression(67, Add), rhs = Counter(28)
+- expression 62 operands: lhs = Counter(26), rhs = Counter(27)
+- expression 63 operands: lhs = Expression(64, Add), rhs = Zero
+- expression 64 operands: lhs = Counter(25), rhs = Expression(65, Add)
+- expression 65 operands: lhs = Expression(66, Add), rhs = Counter(29)
+- expression 66 operands: lhs = Expression(67, Add), rhs = Counter(28)
+- expression 67 operands: lhs = Counter(26), rhs = Counter(27)
+- expression 68 operands: lhs = Counter(31), rhs = Expression(124, Add)
+- expression 69 operands: lhs = Expression(125, Add), rhs = Counter(35)
+- expression 70 operands: lhs = Expression(126, Add), rhs = Counter(34)
+- expression 71 operands: lhs = Counter(32), rhs = Counter(33)
+- expression 72 operands: lhs = Counter(30), rhs = Zero
+- expression 73 operands: lhs = Expression(86, Add), rhs = Counter(31)
+- expression 74 operands: lhs = Counter(30), rhs = Zero
+- expression 75 operands: lhs = Expression(85, Sub), rhs = Counter(10)
+- expression 76 operands: lhs = Expression(86, Add), rhs = Counter(31)
+- expression 77 operands: lhs = Counter(30), rhs = Zero
+- expression 78 operands: lhs = Expression(84, Sub), rhs = Counter(32)
+- expression 79 operands: lhs = Expression(85, Sub), rhs = Counter(10)
+- expression 80 operands: lhs = Expression(86, Add), rhs = Counter(31)
+- expression 81 operands: lhs = Counter(30), rhs = Zero
+- expression 82 operands: lhs = Expression(83, Sub), rhs = Counter(33)
+- expression 83 operands: lhs = Expression(84, Sub), rhs = Counter(32)
+- expression 84 operands: lhs = Expression(85, Sub), rhs = Counter(10)
+- expression 85 operands: lhs = Expression(86, Add), rhs = Counter(31)
+- expression 86 operands: lhs = Counter(30), rhs = Zero
+- expression 87 operands: lhs = Expression(126, Add), rhs = Counter(34)
+- expression 88 operands: lhs = Counter(32), rhs = Counter(33)
+- expression 89 operands: lhs = Expression(125, Add), rhs = Counter(35)
+- expression 90 operands: lhs = Expression(126, Add), rhs = Counter(34)
+- expression 91 operands: lhs = Counter(32), rhs = Counter(33)
+- expression 92 operands: lhs = Counter(4), rhs = Expression(134, Add)
+- expression 93 operands: lhs = Expression(135, Add), rhs = Counter(8)
+- expression 94 operands: lhs = Expression(136, Add), rhs = Counter(7)
+- expression 95 operands: lhs = Counter(5), rhs = Counter(6)
+- expression 96 operands: lhs = Expression(123, Add), rhs = Zero
+- expression 97 operands: lhs = Counter(31), rhs = Expression(124, Add)
+- expression 98 operands: lhs = Expression(125, Add), rhs = Counter(35)
+- expression 99 operands: lhs = Expression(126, Add), rhs = Counter(34)
+- expression 100 operands: lhs = Counter(32), rhs = Counter(33)
+- expression 101 operands: lhs = Expression(123, Add), rhs = Counter(4)
+- expression 102 operands: lhs = Counter(31), rhs = Expression(124, Add)
+- expression 103 operands: lhs = Expression(125, Add), rhs = Counter(35)
+- expression 104 operands: lhs = Expression(126, Add), rhs = Counter(34)
+- expression 105 operands: lhs = Counter(32), rhs = Counter(33)
+- expression 106 operands: lhs = Expression(122, Sub), rhs = Counter(9)
+- expression 107 operands: lhs = Expression(123, Add), rhs = Counter(4)
+- expression 108 operands: lhs = Counter(31), rhs = Expression(124, Add)
+- expression 109 operands: lhs = Expression(125, Add), rhs = Counter(35)
+- expression 110 operands: lhs = Expression(126, Add), rhs = Counter(34)
+- expression 111 operands: lhs = Counter(32), rhs = Counter(33)
+- expression 112 operands: lhs = Expression(121, Sub), rhs = Counter(5)
+- expression 113 operands: lhs = Expression(122, Sub), rhs = Counter(9)
+- expression 114 operands: lhs = Expression(123, Add), rhs = Counter(4)
+- expression 115 operands: lhs = Counter(31), rhs = Expression(124, Add)
+- expression 116 operands: lhs = Expression(125, Add), rhs = Counter(35)
+- expression 117 operands: lhs = Expression(126, Add), rhs = Counter(34)
+- expression 118 operands: lhs = Counter(32), rhs = Counter(33)
+- expression 119 operands: lhs = Expression(120, Sub), rhs = Counter(6)
+- expression 120 operands: lhs = Expression(121, Sub), rhs = Counter(5)
+- expression 121 operands: lhs = Expression(122, Sub), rhs = Counter(9)
+- expression 122 operands: lhs = Expression(123, Add), rhs = Counter(4)
+- expression 123 operands: lhs = Counter(31), rhs = Expression(124, Add)
+- expression 124 operands: lhs = Expression(125, Add), rhs = Counter(35)
+- expression 125 operands: lhs = Expression(126, Add), rhs = Counter(34)
+- expression 126 operands: lhs = Counter(32), rhs = Counter(33)
+- expression 127 operands: lhs = Expression(136, Add), rhs = Counter(7)
+- expression 128 operands: lhs = Counter(5), rhs = Counter(6)
+- expression 129 operands: lhs = Expression(135, Add), rhs = Counter(8)
+- expression 130 operands: lhs = Expression(136, Add), rhs = Counter(7)
+- expression 131 operands: lhs = Counter(5), rhs = Counter(6)
+- expression 132 operands: lhs = Expression(133, Add), rhs = Expression(137, Add)
+- expression 133 operands: lhs = Counter(4), rhs = Expression(134, Add)
+- expression 134 operands: lhs = Expression(135, Add), rhs = Counter(8)
+- expression 135 operands: lhs = Expression(136, Add), rhs = Counter(7)
+- expression 136 operands: lhs = Counter(5), rhs = Counter(6)
+- expression 137 operands: lhs = Expression(138, Add), rhs = Expression(141, Sub)
+- expression 138 operands: lhs = Expression(139, Add), rhs = Expression(140, Add)
+- expression 139 operands: lhs = Counter(9), rhs = Counter(10)
+- expression 140 operands: lhs = Counter(11), rhs = Counter(12)
+- expression 141 operands: lhs = Expression(142, Sub), rhs = Counter(3)
+- expression 142 operands: lhs = Expression(143, Add), rhs = Counter(2)
+- expression 143 operands: lhs = Counter(1), rhs = Zero
+Number of file 0 mappings: 68
+- Code(Counter(0)) at (prev + 3, 1) to (start + 2, 12)
+- Code(Counter(1)) at (prev + 2, 13) to (start + 2, 6)
+- Code(Zero) at (prev + 2, 6) to (start + 0, 7)
+- Code(Expression(0, Add)) at (prev + 3, 9) to (start + 0, 10)
+    = (c2 + (((c13 + c14) + c15) + c16))
+- Code(Expression(143, Add)) at (prev + 0, 16) to (start + 0, 29)
+    = (c1 + Zero)
+- Code(Counter(2)) at (prev + 1, 9) to (start + 1, 10)
+- Code(Expression(142, Sub)) at (prev + 2, 15) to (start + 0, 28)
+    = ((c1 + Zero) - c2)
+- Code(Counter(3)) at (prev + 1, 12) to (start + 0, 25)
+- Code(Expression(9, Sub)) at (prev + 0, 29) to (start + 0, 42)
+    = (c3 - c13)
+- Code(Expression(8, Sub)) at (prev + 0, 46) to (start + 0, 60)
+    = ((c3 - c13) - c14)
+- Code(Expression(13, Add)) at (prev + 0, 61) to (start + 2, 10)
+    = ((c13 + c14) + c15)
+- Code(Counter(16)) at (prev + 2, 10) to (start + 0, 11)
+- Code(Expression(12, Add)) at (prev + 1, 9) to (start + 1, 18)
+    = (((c13 + c14) + c15) + c16)
+- Code(Expression(141, Sub)) at (prev + 3, 9) to (start + 0, 15)
+    = (((c1 + Zero) - c2) - c3)
+- Code(Expression(18, Add)) at (prev + 3, 9) to (start + 1, 12)
+    = ((c2 + (((c13 + c14) + c15) + c16)) + Zero)
+- Code(Counter(17)) at (prev + 1, 13) to (start + 2, 6)
+- Code(Zero) at (prev + 2, 6) to (start + 0, 7)
+- Code(Expression(33, Add)) at (prev + 2, 8) to (start + 0, 21)
+    = (c17 + Zero)
+- Code(Counter(18)) at (prev + 0, 22) to (start + 2, 6)
+- Code(Expression(32, Sub)) at (prev + 2, 15) to (start + 0, 28)
+    = ((c17 + Zero) - c18)
+- Code(Expression(31, Sub)) at (prev + 1, 12) to (start + 0, 25)
+    = (((c17 + Zero) - c18) - c12)
+- Code(Expression(30, Sub)) at (prev + 0, 29) to (start + 0, 42)
+    = ((((c17 + Zero) - c18) - c12) - c19)
+- Code(Expression(29, Sub)) at (prev + 0, 46) to (start + 0, 60)
+    = (((((c17 + Zero) - c18) - c12) - c19) - c20)
+- Code(Expression(41, Add)) at (prev + 0, 61) to (start + 2, 10)
+    = ((c19 + c20) + c21)
+- Code(Counter(22)) at (prev + 2, 10) to (start + 0, 11)
+- Code(Expression(40, Add)) at (prev + 1, 9) to (start + 0, 23)
+    = (((c19 + c20) + c21) + c22)
+- Code(Counter(12)) at (prev + 2, 9) to (start + 0, 15)
+- Code(Expression(39, Add)) at (prev + 3, 8) to (start + 0, 12)
+    = (c18 + (((c19 + c20) + c21) + c22))
+- Code(Counter(23)) at (prev + 1, 13) to (start + 1, 16)
+- Code(Counter(24)) at (prev + 1, 17) to (start + 2, 10)
+- Code(Zero) at (prev + 2, 10) to (start + 0, 11)
+- Code(Expression(57, Add)) at (prev + 2, 12) to (start + 0, 25)
+    = (c24 + Zero)
+- Code(Counter(25)) at (prev + 0, 26) to (start + 2, 10)
+- Code(Expression(56, Sub)) at (prev + 3, 17) to (start + 0, 30)
+    = ((c24 + Zero) - c25)
+- Code(Expression(55, Sub)) at (prev + 1, 16) to (start + 0, 29)
+    = (((c24 + Zero) - c25) - c11)
+- Code(Expression(54, Sub)) at (prev + 0, 33) to (start + 0, 46)
+    = ((((c24 + Zero) - c25) - c11) - c26)
+- Code(Expression(53, Sub)) at (prev + 0, 50) to (start + 0, 64)
+    = (((((c24 + Zero) - c25) - c11) - c26) - c27)
+- Code(Expression(66, Add)) at (prev + 0, 65) to (start + 2, 14)
+    = ((c26 + c27) + c28)
+- Code(Counter(29)) at (prev + 2, 14) to (start + 0, 15)
+- Code(Expression(65, Add)) at (prev + 1, 13) to (start + 0, 27)
+    = (((c26 + c27) + c28) + c29)
+- Code(Counter(11)) at (prev + 2, 13) to (start + 0, 19)
+- Code(Zero) at (prev + 2, 6) to (start + 0, 7)
+- Code(Expression(63, Add)) at (prev + 2, 9) to (start + 1, 12)
+    = ((c25 + (((c26 + c27) + c28) + c29)) + Zero)
+- Code(Counter(30)) at (prev + 1, 13) to (start + 2, 6)
+- Code(Zero) at (prev + 2, 6) to (start + 0, 7)
+- Code(Expression(123, Add)) at (prev + 2, 9) to (start + 0, 10)
+    = (c31 + (((c32 + c33) + c34) + c35))
+- Code(Expression(86, Add)) at (prev + 0, 16) to (start + 0, 29)
+    = (c30 + Zero)
+- Code(Counter(31)) at (prev + 0, 30) to (start + 2, 6)
+- Code(Expression(85, Sub)) at (prev + 2, 15) to (start + 0, 28)
+    = ((c30 + Zero) - c31)
+- Code(Expression(84, Sub)) at (prev + 1, 12) to (start + 0, 25)
+    = (((c30 + Zero) - c31) - c10)
+- Code(Expression(83, Sub)) at (prev + 0, 29) to (start + 0, 42)
+    = ((((c30 + Zero) - c31) - c10) - c32)
+- Code(Expression(82, Sub)) at (prev + 0, 46) to (start + 0, 60)
+    = (((((c30 + Zero) - c31) - c10) - c32) - c33)
+- Code(Expression(125, Add)) at (prev + 0, 61) to (start + 2, 10)
+    = ((c32 + c33) + c34)
+- Code(Counter(35)) at (prev + 2, 10) to (start + 0, 11)
+- Code(Expression(124, Add)) at (prev + 1, 9) to (start + 0, 23)
+    = (((c32 + c33) + c34) + c35)
+- Code(Counter(10)) at (prev + 2, 13) to (start + 2, 15)
+- Code(Expression(133, Add)) at (prev + 5, 9) to (start + 0, 10)
+    = (c4 + (((c5 + c6) + c7) + c8))
+- Code(Expression(96, Add)) at (prev + 0, 16) to (start + 0, 29)
+    = ((c31 + (((c32 + c33) + c34) + c35)) + Zero)
+- Code(Counter(4)) at (prev + 0, 30) to (start + 2, 6)
+- Code(Expression(122, Sub)) at (prev + 2, 15) to (start + 0, 28)
+    = ((c31 + (((c32 + c33) + c34) + c35)) - c4)
+- Code(Expression(121, Sub)) at (prev + 1, 12) to (start + 0, 25)
+    = (((c31 + (((c32 + c33) + c34) + c35)) - c4) - c9)
+- Code(Expression(120, Sub)) at (prev + 0, 29) to (start + 0, 42)
+    = ((((c31 + (((c32 + c33) + c34) + c35)) - c4) - c9) - c5)
+- Code(Expression(119, Sub)) at (prev + 0, 46) to (start + 0, 60)
+    = (((((c31 + (((c32 + c33) + c34) + c35)) - c4) - c9) - c5) - c6)
+- Code(Expression(135, Add)) at (prev + 0, 61) to (start + 2, 10)
+    = ((c5 + c6) + c7)
+- Code(Counter(8)) at (prev + 2, 10) to (start + 0, 11)
+- Code(Expression(134, Add)) at (prev + 1, 9) to (start + 0, 23)
+    = (((c5 + c6) + c7) + c8)
+- Code(Counter(9)) at (prev + 2, 9) to (start + 0, 15)
+- Code(Expression(132, Add)) at (prev + 2, 1) to (start + 0, 2)
+    = ((c4 + (((c5 + c6) + c7) + c8)) + (((c9 + c10) + (c11 + c12)) + (((c1 + Zero) - c2) - c3)))
+

tests/coverage-map/status-quo/conditions.rs

@@ -0,0 +1,86 @@
+#![allow(unused_assignments, unused_variables)]
+
+fn main() {
+    let mut countdown = 0;
+    if true {
+        countdown = 10;
+    }
+
+    const B: u32 = 100;
+    let x = if countdown > 7 {
+        countdown -= 4;
+        B
+    } else if countdown > 2 {
+        if countdown < 1 || countdown > 5 || countdown != 9 {
+            countdown = 0;
+        }
+        countdown -= 5;
+        countdown
+    } else {
+        return;
+    };
+
+    let mut countdown = 0;
+    if true {
+        countdown = 10;
+    }
+
+    if countdown > 7 {
+        countdown -= 4;
+    } else if countdown > 2 {
+        if countdown < 1 || countdown > 5 || countdown != 9 {
+            countdown = 0;
+        }
+        countdown -= 5;
+    } else {
+        return;
+    }
+
+    if true {
+        let mut countdown = 0;
+        if true {
+            countdown = 10;
+        }
+
+        if countdown > 7 {
+            countdown -= 4;
+        }
+        else if countdown > 2 {
+            if countdown < 1 || countdown > 5 || countdown != 9 {
+                countdown = 0;
+            }
+            countdown -= 5;
+        } else {
+            return;
+        }
+    }
+
+    let mut countdown = 0;
+    if true {
+        countdown = 1;
+    }
+
+    let z = if countdown > 7 {
+        countdown -= 4;
+    } else if countdown > 2 {
+        if countdown < 1 || countdown > 5 || countdown != 9 {
+            countdown = 0;
+        }
+        countdown -= 5;
+    } else {
+        let should_be_reachable = countdown;
+        println!("reached");
+        return;
+    };
+
+    let w = if countdown > 7 {
+        countdown -= 4;
+    } else if countdown > 2 {
+        if countdown < 1 || countdown > 5 || countdown != 9 {
+            countdown = 0;
+        }
+        countdown -= 5;
+    } else {
+        return;
+    };
+}

tests/coverage-map/status-quo/continue.cov-map

@@ -0,0 +1,85 @@
+Function name: continue::main
+Raw bytes (216): 0x[01, 01, 1f, 01, 07, 05, 09, 03, 0d, 0d, 1f, 11, 15, 1b, 19, 0d, 1f, 11, 15, 15, 00, 19, 37, 1d, 21, 33, 25, 19, 37, 1d, 21, 1d, 00, 25, 4f, 29, 2d, 4b, 31, 25, 4f, 29, 2d, 31, 67, 35, 39, 5f, 3d, 31, 67, 35, 39, 35, 39, 3d, 41, 73, 45, 3d, 41, 41, 00, 49, 45, 1e, 01, 03, 01, 03, 12, 03, 04, 0e, 00, 13, 0a, 01, 0f, 00, 16, 05, 02, 11, 00, 19, 09, 02, 12, 04, 0e, 1b, 06, 0e, 00, 13, 16, 01, 0f, 00, 16, 15, 01, 16, 02, 0e, 11, 04, 11, 00, 19, 23, 03, 09, 00, 0e, 33, 02, 0e, 00, 13, 2e, 01, 0f, 00, 16, 1d, 01, 15, 02, 0e, 21, 04, 11, 00, 19, 3b, 03, 09, 00, 0e, 4b, 02, 0e, 00, 13, 46, 01, 0c, 00, 13, 29, 01, 0d, 00, 15, 2d, 01, 0a, 01, 0e, 5f, 03, 0e, 00, 13, 5a, 01, 0f, 00, 16, 39, 01, 16, 02, 0e, 35, 03, 12, 02, 0e, 67, 04, 09, 00, 0e, 73, 02, 0e, 00, 13, 6e, 01, 0f, 00, 16, 41, 01, 16, 02, 0e, 49, 04, 11, 00, 16, 77, 03, 09, 00, 0e, 7b, 02, 0d, 01, 02]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 31
+- expression 0 operands: lhs = Counter(0), rhs = Expression(1, Add)
+- expression 1 operands: lhs = Counter(1), rhs = Counter(2)
+- expression 2 operands: lhs = Expression(0, Add), rhs = Counter(3)
+- expression 3 operands: lhs = Counter(3), rhs = Expression(7, Add)
+- expression 4 operands: lhs = Counter(4), rhs = Counter(5)
+- expression 5 operands: lhs = Expression(6, Add), rhs = Counter(6)
+- expression 6 operands: lhs = Counter(3), rhs = Expression(7, Add)
+- expression 7 operands: lhs = Counter(4), rhs = Counter(5)
+- expression 8 operands: lhs = Counter(5), rhs = Zero
+- expression 9 operands: lhs = Counter(6), rhs = Expression(13, Add)
+- expression 10 operands: lhs = Counter(7), rhs = Counter(8)
+- expression 11 operands: lhs = Expression(12, Add), rhs = Counter(9)
+- expression 12 operands: lhs = Counter(6), rhs = Expression(13, Add)
+- expression 13 operands: lhs = Counter(7), rhs = Counter(8)
+- expression 14 operands: lhs = Counter(7), rhs = Zero
+- expression 15 operands: lhs = Counter(9), rhs = Expression(19, Add)
+- expression 16 operands: lhs = Counter(10), rhs = Counter(11)
+- expression 17 operands: lhs = Expression(18, Add), rhs = Counter(12)
+- expression 18 operands: lhs = Counter(9), rhs = Expression(19, Add)
+- expression 19 operands: lhs = Counter(10), rhs = Counter(11)
+- expression 20 operands: lhs = Counter(12), rhs = Expression(25, Add)
+- expression 21 operands: lhs = Counter(13), rhs = Counter(14)
+- expression 22 operands: lhs = Expression(23, Add), rhs = Counter(15)
+- expression 23 operands: lhs = Counter(12), rhs = Expression(25, Add)
+- expression 24 operands: lhs = Counter(13), rhs = Counter(14)
+- expression 25 operands: lhs = Counter(13), rhs = Counter(14)
+- expression 26 operands: lhs = Counter(15), rhs = Counter(16)
+- expression 27 operands: lhs = Expression(28, Add), rhs = Counter(17)
+- expression 28 operands: lhs = Counter(15), rhs = Counter(16)
+- expression 29 operands: lhs = Counter(16), rhs = Zero
+- expression 30 operands: lhs = Counter(18), rhs = Counter(17)
+Number of file 0 mappings: 30
+- Code(Counter(0)) at (prev + 3, 1) to (start + 3, 18)
+- Code(Expression(0, Add)) at (prev + 4, 14) to (start + 0, 19)
+    = (c0 + (c1 + c2))
+- Code(Expression(2, Sub)) at (prev + 1, 15) to (start + 0, 22)
+    = ((c0 + (c1 + c2)) - c3)
+- Code(Counter(1)) at (prev + 2, 17) to (start + 0, 25)
+- Code(Counter(2)) at (prev + 2, 18) to (start + 4, 14)
+- Code(Expression(6, Add)) at (prev + 6, 14) to (start + 0, 19)
+    = (c3 + (c4 + c5))
+- Code(Expression(5, Sub)) at (prev + 1, 15) to (start + 0, 22)
+    = ((c3 + (c4 + c5)) - c6)
+- Code(Counter(5)) at (prev + 1, 22) to (start + 2, 14)
+- Code(Counter(4)) at (prev + 4, 17) to (start + 0, 25)
+- Code(Expression(8, Add)) at (prev + 3, 9) to (start + 0, 14)
+    = (c5 + Zero)
+- Code(Expression(12, Add)) at (prev + 2, 14) to (start + 0, 19)
+    = (c6 + (c7 + c8))
+- Code(Expression(11, Sub)) at (prev + 1, 15) to (start + 0, 22)
+    = ((c6 + (c7 + c8)) - c9)
+- Code(Counter(7)) at (prev + 1, 21) to (start + 2, 14)
+- Code(Counter(8)) at (prev + 4, 17) to (start + 0, 25)
+- Code(Expression(14, Add)) at (prev + 3, 9) to (start + 0, 14)
+    = (c7 + Zero)
+- Code(Expression(18, Add)) at (prev + 2, 14) to (start + 0, 19)
+    = (c9 + (c10 + c11))
+- Code(Expression(17, Sub)) at (prev + 1, 12) to (start + 0, 19)
+    = ((c9 + (c10 + c11)) - c12)
+- Code(Counter(10)) at (prev + 1, 13) to (start + 0, 21)
+- Code(Counter(11)) at (prev + 1, 10) to (start + 1, 14)
+- Code(Expression(23, Add)) at (prev + 3, 14) to (start + 0, 19)
+    = (c12 + (c13 + c14))
+- Code(Expression(22, Sub)) at (prev + 1, 15) to (start + 0, 22)
+    = ((c12 + (c13 + c14)) - c15)
+- Code(Counter(14)) at (prev + 1, 22) to (start + 2, 14)
+- Code(Counter(13)) at (prev + 3, 18) to (start + 2, 14)
+- Code(Expression(25, Add)) at (prev + 4, 9) to (start + 0, 14)
+    = (c13 + c14)
+- Code(Expression(28, Add)) at (prev + 2, 14) to (start + 0, 19)
+    = (c15 + c16)
+- Code(Expression(27, Sub)) at (prev + 1, 15) to (start + 0, 22)
+    = ((c15 + c16) - c17)
+- Code(Counter(16)) at (prev + 1, 22) to (start + 2, 14)
+- Code(Counter(18)) at (prev + 4, 17) to (start + 0, 22)
+- Code(Expression(29, Add)) at (prev + 3, 9) to (start + 0, 14)
+    = (c16 + Zero)
+- Code(Expression(30, Add)) at (prev + 2, 13) to (start + 1, 2)
+    = (c18 + c17)
+

tests/coverage-map/status-quo/continue.rs

@@ -0,0 +1,69 @@
+#![allow(unused_assignments, unused_variables)]
+
+fn main() {
+    let is_true = std::env::args().len() == 1;
+
+    let mut x = 0;
+    for _ in 0..10 {
+        match is_true {
+            true => {
+                continue;
+            }
+            _ => {
+                x = 1;
+            }
+        }
+        x = 3;
+    }
+    for _ in 0..10 {
+        match is_true {
+            false => {
+                x = 1;
+            }
+            _ => {
+                continue;
+            }
+        }
+        x = 3;
+    }
+    for _ in 0..10 {
+        match is_true {
+            true => {
+                x = 1;
+            }
+            _ => {
+                continue;
+            }
+        }
+        x = 3;
+    }
+    for _ in 0..10 {
+        if is_true {
+            continue;
+        }
+        x = 3;
+    }
+    for _ in 0..10 {
+        match is_true {
+            false => {
+                x = 1;
+            }
+            _ => {
+                let _ = x;
+            }
+        }
+        x = 3;
+    }
+    for _ in 0..10 {
+        match is_true {
+            false => {
+                x = 1;
+            }
+            _ => {
+                break;
+            }
+        }
+        x = 3;
+    }
+    let _ = x;
+}

tests/coverage-map/status-quo/dead_code.cov-map

@@ -0,0 +1,37 @@
+Function name: dead_code::main
+Raw bytes (28): 0x[01, 01, 02, 01, 05, 05, 02, 04, 01, 1b, 01, 07, 0f, 05, 07, 10, 02, 06, 02, 02, 06, 00, 07, 07, 01, 01, 00, 02]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 2
+- expression 0 operands: lhs = Counter(0), rhs = Counter(1)
+- expression 1 operands: lhs = Counter(1), rhs = Expression(0, Sub)
+Number of file 0 mappings: 4
+- Code(Counter(0)) at (prev + 27, 1) to (start + 7, 15)
+- Code(Counter(1)) at (prev + 7, 16) to (start + 2, 6)
+- Code(Expression(0, Sub)) at (prev + 2, 6) to (start + 0, 7)
+    = (c0 - c1)
+- Code(Expression(1, Add)) at (prev + 1, 1) to (start + 0, 2)
+    = (c1 + (c0 - c1))
+
+Function name: dead_code::unused_fn (unused)
+Raw bytes (24): 0x[01, 01, 00, 04, 01, 0f, 01, 07, 0f, 00, 07, 10, 02, 06, 00, 02, 06, 00, 07, 00, 01, 01, 00, 02]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 0
+Number of file 0 mappings: 4
+- Code(Counter(0)) at (prev + 15, 1) to (start + 7, 15)
+- Code(Zero) at (prev + 7, 16) to (start + 2, 6)
+- Code(Zero) at (prev + 2, 6) to (start + 0, 7)
+- Code(Zero) at (prev + 1, 1) to (start + 0, 2)
+
+Function name: dead_code::unused_pub_fn_not_in_library (unused)
+Raw bytes (24): 0x[01, 01, 00, 04, 01, 03, 01, 07, 0f, 00, 07, 10, 02, 06, 00, 02, 06, 00, 07, 00, 01, 01, 00, 02]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 0
+Number of file 0 mappings: 4
+- Code(Counter(0)) at (prev + 3, 1) to (start + 7, 15)
+- Code(Zero) at (prev + 7, 16) to (start + 2, 6)
+- Code(Zero) at (prev + 2, 6) to (start + 0, 7)
+- Code(Zero) at (prev + 1, 1) to (start + 0, 2)
+

tests/coverage-map/status-quo/dead_code.rs

@@ -0,0 +1,37 @@
+#![allow(dead_code, unused_assignments, unused_variables)]
+
+pub fn unused_pub_fn_not_in_library() {
+    // Initialize test constants in a way that cannot be determined at compile time, to ensure
+    // rustc and LLVM cannot optimize out statements (or coverage counters) downstream from
+    // dependent conditions.
+    let is_true = std::env::args().len() == 1;
+
+    let mut countdown = 0;
+    if is_true {
+        countdown = 10;
+    }
+}
+
+fn unused_fn() {
+    // Initialize test constants in a way that cannot be determined at compile time, to ensure
+    // rustc and LLVM cannot optimize out statements (or coverage counters) downstream from
+    // dependent conditions.
+    let is_true = std::env::args().len() == 1;
+
+    let mut countdown = 0;
+    if is_true {
+        countdown = 10;
+    }
+}
+
+fn main() {
+    // Initialize test constants in a way that cannot be determined at compile time, to ensure
+    // rustc and LLVM cannot optimize out statements (or coverage counters) downstream from
+    // dependent conditions.
+    let is_true = std::env::args().len() == 1;
+
+    let mut countdown = 0;
+    if is_true {
+        countdown = 10;
+    }
+}

tests/coverage-map/status-quo/drop_trait.cov-map

@@ -0,0 +1,21 @@
+Function name: <drop_trait::Firework as core::ops::drop::Drop>::drop
+Raw bytes (9): 0x[01, 01, 00, 01, 01, 09, 05, 02, 06]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 0
+Number of file 0 mappings: 1
+- Code(Counter(0)) at (prev + 9, 5) to (start + 2, 6)
+
+Function name: drop_trait::main
+Raw bytes (26): 0x[01, 01, 01, 05, 00, 04, 01, 0e, 01, 05, 0c, 05, 06, 09, 01, 16, 00, 02, 06, 04, 0b, 03, 05, 01, 00, 02]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 1
+- expression 0 operands: lhs = Counter(1), rhs = Zero
+Number of file 0 mappings: 4
+- Code(Counter(0)) at (prev + 14, 1) to (start + 5, 12)
+- Code(Counter(1)) at (prev + 6, 9) to (start + 1, 22)
+- Code(Zero) at (prev + 2, 6) to (start + 4, 11)
+- Code(Expression(0, Add)) at (prev + 5, 1) to (start + 0, 2)
+    = (c1 + Zero)
+

tests/coverage-map/status-quo/drop_trait.rs

@@ -0,0 +1,33 @@
+#![allow(unused_assignments)]
+// failure-status: 1
+
+struct Firework {
+    strength: i32,
+}
+
+impl Drop for Firework {
+    fn drop(&mut self) {
+        println!("BOOM times {}!!!", self.strength);
+    }
+}
+
+fn main() -> Result<(), u8> {
+    let _firecracker = Firework { strength: 1 };
+
+    let _tnt = Firework { strength: 100 };
+
+    if true {
+        println!("Exiting with error...");
+        return Err(1);
+    }
+
+    let _ = Firework { strength: 1000 };
+
+    Ok(())
+}
+
+// Expected program output:
+//   Exiting with error...
+//   BOOM times 100!!!
+//   BOOM times 1!!!
+//   Error: 1

tests/coverage-map/status-quo/generator.cov-map

@@ -0,0 +1,58 @@
+Function name: generator::get_u32
+Raw bytes (28): 0x[01, 01, 02, 01, 05, 05, 02, 04, 01, 0b, 01, 01, 0b, 05, 01, 0e, 00, 13, 02, 00, 1d, 00, 3c, 07, 01, 01, 00, 02]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 2
+- expression 0 operands: lhs = Counter(0), rhs = Counter(1)
+- expression 1 operands: lhs = Counter(1), rhs = Expression(0, Sub)
+Number of file 0 mappings: 4
+- Code(Counter(0)) at (prev + 11, 1) to (start + 1, 11)
+- Code(Counter(1)) at (prev + 1, 14) to (start + 0, 19)
+- Code(Expression(0, Sub)) at (prev + 0, 29) to (start + 0, 60)
+    = (c0 - c1)
+- Code(Expression(1, Add)) at (prev + 1, 1) to (start + 0, 2)
+    = (c1 + (c0 - c1))
+
+Function name: generator::main
+Raw bytes (71): 0x[01, 01, 0b, 01, 00, 05, 0b, 09, 0d, 11, 00, 11, 15, 2a, 19, 11, 15, 15, 19, 26, 00, 2a, 19, 11, 15, 09, 01, 0f, 01, 02, 19, 03, 07, 0b, 00, 2e, 11, 01, 2b, 00, 2d, 07, 01, 0e, 00, 35, 0f, 02, 0b, 00, 2e, 2a, 01, 22, 00, 27, 26, 00, 2c, 00, 2e, 1f, 01, 0e, 00, 35, 23, 02, 01, 00, 02]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 11
+- expression 0 operands: lhs = Counter(0), rhs = Zero
+- expression 1 operands: lhs = Counter(1), rhs = Expression(2, Add)
+- expression 2 operands: lhs = Counter(2), rhs = Counter(3)
+- expression 3 operands: lhs = Counter(4), rhs = Zero
+- expression 4 operands: lhs = Counter(4), rhs = Counter(5)
+- expression 5 operands: lhs = Expression(10, Sub), rhs = Counter(6)
+- expression 6 operands: lhs = Counter(4), rhs = Counter(5)
+- expression 7 operands: lhs = Counter(5), rhs = Counter(6)
+- expression 8 operands: lhs = Expression(9, Sub), rhs = Zero
+- expression 9 operands: lhs = Expression(10, Sub), rhs = Counter(6)
+- expression 10 operands: lhs = Counter(4), rhs = Counter(5)
+Number of file 0 mappings: 9
+- Code(Counter(0)) at (prev + 15, 1) to (start + 2, 25)
+- Code(Expression(0, Add)) at (prev + 7, 11) to (start + 0, 46)
+    = (c0 + Zero)
+- Code(Counter(4)) at (prev + 1, 43) to (start + 0, 45)
+- Code(Expression(1, Add)) at (prev + 1, 14) to (start + 0, 53)
+    = (c1 + (c2 + c3))
+- Code(Expression(3, Add)) at (prev + 2, 11) to (start + 0, 46)
+    = (c4 + Zero)
+- Code(Expression(10, Sub)) at (prev + 1, 34) to (start + 0, 39)
+    = (c4 - c5)
+- Code(Expression(9, Sub)) at (prev + 0, 44) to (start + 0, 46)
+    = ((c4 - c5) - c6)
+- Code(Expression(7, Add)) at (prev + 1, 14) to (start + 0, 53)
+    = (c5 + c6)
+- Code(Expression(8, Add)) at (prev + 2, 1) to (start + 0, 2)
+    = (((c4 - c5) - c6) + Zero)
+
+Function name: generator::main::{closure#0}
+Raw bytes (14): 0x[01, 01, 00, 02, 01, 11, 1c, 01, 1f, 05, 02, 10, 01, 06]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 0
+Number of file 0 mappings: 2
+- Code(Counter(0)) at (prev + 17, 28) to (start + 1, 31)
+- Code(Counter(1)) at (prev + 2, 16) to (start + 1, 6)
+

tests/coverage-map/status-quo/generator.rs

@@ -0,0 +1,30 @@
+#![feature(generators, generator_trait)]
+
+use std::ops::{Generator, GeneratorState};
+use std::pin::Pin;
+
+// The following implementation of a function called from a `yield` statement
+// (apparently requiring the Result and the `String` type or constructor)
+// creates conditions where the `generator::StateTransform` MIR transform will
+// drop all `Counter` `Coverage` statements from a MIR. `simplify.rs` has logic
+// to handle this condition, and still report dead block coverage.
+fn get_u32(val: bool) -> Result<u32, String> {
+    if val { Ok(1) } else { Err(String::from("some error")) }
+}
+
+fn main() {
+    let is_true = std::env::args().len() == 1;
+    let mut generator = || {
+        yield get_u32(is_true);
+        return "foo";
+    };
+
+    match Pin::new(&mut generator).resume(()) {
+        GeneratorState::Yielded(Ok(1)) => {}
+        _ => panic!("unexpected return from resume"),
+    }
+    match Pin::new(&mut generator).resume(()) {
+        GeneratorState::Complete("foo") => {}
+        _ => panic!("unexpected return from resume"),
+    }
+}

tests/coverage-map/status-quo/generics.cov-map

@@ -0,0 +1,45 @@
+Function name: <generics::Firework<f64> as core::ops::drop::Drop>::drop
+Raw bytes (9): 0x[01, 01, 00, 01, 01, 11, 05, 02, 06]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 0
+Number of file 0 mappings: 1
+- Code(Counter(0)) at (prev + 17, 5) to (start + 2, 6)
+
+Function name: <generics::Firework<f64>>::set_strength
+Raw bytes (9): 0x[01, 01, 00, 01, 01, 0a, 05, 02, 06]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 0
+Number of file 0 mappings: 1
+- Code(Counter(0)) at (prev + 10, 5) to (start + 2, 6)
+
+Function name: <generics::Firework<i32> as core::ops::drop::Drop>::drop
+Raw bytes (9): 0x[01, 01, 00, 01, 01, 11, 05, 02, 06]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 0
+Number of file 0 mappings: 1
+- Code(Counter(0)) at (prev + 17, 5) to (start + 2, 6)
+
+Function name: <generics::Firework<i32>>::set_strength
+Raw bytes (9): 0x[01, 01, 00, 01, 01, 0a, 05, 02, 06]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 0
+Number of file 0 mappings: 1
+- Code(Counter(0)) at (prev + 10, 5) to (start + 2, 6)
+
+Function name: generics::main
+Raw bytes (26): 0x[01, 01, 01, 05, 00, 04, 01, 16, 01, 08, 0c, 05, 09, 09, 01, 16, 00, 02, 06, 04, 0b, 03, 05, 01, 00, 02]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 1
+- expression 0 operands: lhs = Counter(1), rhs = Zero
+Number of file 0 mappings: 4
+- Code(Counter(0)) at (prev + 22, 1) to (start + 8, 12)
+- Code(Counter(1)) at (prev + 9, 9) to (start + 1, 22)
+- Code(Zero) at (prev + 2, 6) to (start + 4, 11)
+- Code(Expression(0, Add)) at (prev + 5, 1) to (start + 0, 2)
+    = (c1 + Zero)
+

tests/coverage-map/status-quo/generics.rs

@@ -0,0 +1,44 @@
+#![allow(unused_assignments)]
+// failure-status: 1
+
+struct Firework<T> where T: Copy + std::fmt::Display {
+    strength: T,
+}
+
+impl<T> Firework<T> where T: Copy + std::fmt::Display {
+    #[inline(always)]
+    fn set_strength(&mut self, new_strength: T) {
+        self.strength = new_strength;
+    }
+}
+
+impl<T> Drop for Firework<T> where T: Copy + std::fmt::Display {
+    #[inline(always)]
+    fn drop(&mut self) {
+        println!("BOOM times {}!!!", self.strength);
+    }
+}
+
+fn main() -> Result<(), u8> {
+    let mut firecracker = Firework { strength: 1 };
+    firecracker.set_strength(2);
+
+    let mut tnt = Firework { strength: 100.1 };
+    tnt.set_strength(200.1);
+    tnt.set_strength(300.3);
+
+    if true {
+        println!("Exiting with error...");
+        return Err(1);
+    }
+
+    let _ = Firework { strength: 1000 };
+
+    Ok(())
+}
+
+// Expected program output:
+//   Exiting with error...
+//   BOOM times 100!!!
+//   BOOM times 1!!!
+//   Error: 1

tests/coverage-map/status-quo/if.cov-map

@@ -0,0 +1,15 @@
+Function name: if::main
+Raw bytes (28): 0x[01, 01, 02, 01, 05, 05, 02, 04, 01, 03, 01, 12, 10, 05, 13, 05, 05, 06, 02, 05, 06, 00, 07, 07, 01, 01, 00, 02]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 2
+- expression 0 operands: lhs = Counter(0), rhs = Counter(1)
+- expression 1 operands: lhs = Counter(1), rhs = Expression(0, Sub)
+Number of file 0 mappings: 4
+- Code(Counter(0)) at (prev + 3, 1) to (start + 18, 16)
+- Code(Counter(1)) at (prev + 19, 5) to (start + 5, 6)
+- Code(Expression(0, Sub)) at (prev + 5, 6) to (start + 0, 7)
+    = (c0 - c1)
+- Code(Expression(1, Add)) at (prev + 1, 1) to (start + 0, 2)
+    = (c1 + (c0 - c1))
+

tests/coverage-map/status-quo/if.rs

@@ -0,0 +1,28 @@
+#![allow(unused_assignments, unused_variables)]
+
+fn main() {
+    // Initialize test constants in a way that cannot be determined at compile time, to ensure
+    // rustc and LLVM cannot optimize out statements (or coverage counters) downstream from
+    // dependent conditions.
+    let
+    is_true
+    =
+        std::env::args().len()
+    ==
+        1
+    ;
+    let
+        mut
+    countdown
+    =
+        0
+    ;
+    if
+        is_true
+    {
+        countdown
+        =
+            10
+        ;
+    }
+}

tests/coverage-map/status-quo/if_else.cov-map

@@ -0,0 +1,25 @@
+Function name: if_else::main
+Raw bytes (53): 0x[01, 01, 07, 01, 05, 05, 02, 1b, 09, 05, 02, 09, 16, 1b, 09, 05, 02, 07, 01, 03, 01, 08, 10, 05, 09, 05, 05, 06, 02, 08, 09, 02, 10, 1b, 06, 09, 00, 10, 09, 01, 05, 05, 06, 16, 07, 05, 05, 06, 13, 06, 01, 00, 02]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 7
+- expression 0 operands: lhs = Counter(0), rhs = Counter(1)
+- expression 1 operands: lhs = Counter(1), rhs = Expression(0, Sub)
+- expression 2 operands: lhs = Expression(6, Add), rhs = Counter(2)
+- expression 3 operands: lhs = Counter(1), rhs = Expression(0, Sub)
+- expression 4 operands: lhs = Counter(2), rhs = Expression(5, Sub)
+- expression 5 operands: lhs = Expression(6, Add), rhs = Counter(2)
+- expression 6 operands: lhs = Counter(1), rhs = Expression(0, Sub)
+Number of file 0 mappings: 7
+- Code(Counter(0)) at (prev + 3, 1) to (start + 8, 16)
+- Code(Counter(1)) at (prev + 9, 5) to (start + 5, 6)
+- Code(Expression(0, Sub)) at (prev + 8, 9) to (start + 2, 16)
+    = (c0 - c1)
+- Code(Expression(6, Add)) at (prev + 6, 9) to (start + 0, 16)
+    = (c1 + (c0 - c1))
+- Code(Counter(2)) at (prev + 1, 5) to (start + 5, 6)
+- Code(Expression(5, Sub)) at (prev + 7, 5) to (start + 5, 6)
+    = ((c1 + (c0 - c1)) - c2)
+- Code(Expression(4, Add)) at (prev + 6, 1) to (start + 0, 2)
+    = (c2 + ((c1 + (c0 - c1)) - c2))
+

tests/coverage-map/status-quo/if_else.rs

@@ -0,0 +1,40 @@
+#![allow(unused_assignments, unused_variables)]
+
+fn main() {
+    // Initialize test constants in a way that cannot be determined at compile time, to ensure
+    // rustc and LLVM cannot optimize out statements (or coverage counters) downstream from
+    // dependent conditions.
+    let is_true = std::env::args().len() == 1;
+
+    let mut countdown = 0;
+    if
+        is_true
+    {
+        countdown
+        =
+            10
+        ;
+    }
+    else // Note coverage region difference without semicolon
+    {
+        countdown
+        =
+            100
+    }
+
+    if
+        is_true
+    {
+        countdown
+        =
+            10
+        ;
+    }
+    else
+    {
+        countdown
+        =
+            100
+        ;
+    }
+}

tests/coverage-map/status-quo/inline-dead.cov-map

@@ -0,0 +1,45 @@
+Function name: inline_dead::dead (unused)
+Raw bytes (9): 0x[01, 01, 00, 01, 01, 19, 01, 02, 02]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 0
+Number of file 0 mappings: 1
+- Code(Counter(0)) at (prev + 25, 1) to (start + 2, 2)
+
+Function name: inline_dead::live::<false>
+Raw bytes (28): 0x[01, 01, 02, 01, 05, 05, 02, 04, 01, 10, 01, 01, 09, 00, 02, 09, 00, 0f, 02, 02, 09, 00, 0a, 07, 02, 01, 00, 02]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 2
+- expression 0 operands: lhs = Counter(0), rhs = Counter(1)
+- expression 1 operands: lhs = Counter(1), rhs = Expression(0, Sub)
+Number of file 0 mappings: 4
+- Code(Counter(0)) at (prev + 16, 1) to (start + 1, 9)
+- Code(Zero) at (prev + 2, 9) to (start + 0, 15)
+- Code(Expression(0, Sub)) at (prev + 2, 9) to (start + 0, 10)
+    = (c0 - c1)
+- Code(Expression(1, Add)) at (prev + 2, 1) to (start + 0, 2)
+    = (c1 + (c0 - c1))
+
+Function name: inline_dead::main
+Raw bytes (16): 0x[01, 01, 01, 01, 00, 02, 01, 04, 01, 03, 0d, 03, 07, 06, 02, 02]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 1
+- expression 0 operands: lhs = Counter(0), rhs = Zero
+Number of file 0 mappings: 2
+- Code(Counter(0)) at (prev + 4, 1) to (start + 3, 13)
+- Code(Expression(0, Add)) at (prev + 7, 6) to (start + 2, 2)
+    = (c0 + Zero)
+
+Function name: inline_dead::main::{closure#0}
+Raw bytes (16): 0x[01, 01, 01, 01, 05, 02, 00, 09, 0d, 00, 0e, 03, 02, 05, 00, 06]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 1
+- expression 0 operands: lhs = Counter(0), rhs = Counter(1)
+Number of file 0 mappings: 2
+- Code(Zero) at (prev + 9, 13) to (start + 0, 14)
+- Code(Expression(0, Add)) at (prev + 2, 5) to (start + 0, 6)
+    = (c0 + c1)
+

tests/coverage-map/status-quo/inline-dead.rs

@@ -0,0 +1,27 @@
+// Regression test for issue #98833.
+// compile-flags: -Zinline-mir -Cdebug-assertions=off
+
+fn main() {
+    println!("{}", live::<false>());
+
+    let f = |x: bool| {
+        debug_assert!(
+            x
+        );
+    };
+    f(false);
+}
+
+#[inline]
+fn live<const B: bool>() -> u32 {
+    if B {
+        dead()
+    } else {
+        0
+    }
+}
+
+#[inline]
+fn dead() -> u32 {
+    42
+}

tests/coverage-map/status-quo/inline.cov-map

@@ -0,0 +1,82 @@
+Function name: inline::display::<char>
+Raw bytes (35): 0x[01, 01, 03, 01, 05, 05, 00, 03, 05, 05, 01, 29, 01, 00, 22, 05, 01, 09, 00, 0a, 03, 00, 0e, 00, 10, 07, 00, 11, 02, 06, 0a, 03, 05, 01, 02]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 3
+- expression 0 operands: lhs = Counter(0), rhs = Counter(1)
+- expression 1 operands: lhs = Counter(1), rhs = Zero
+- expression 2 operands: lhs = Expression(0, Add), rhs = Counter(1)
+Number of file 0 mappings: 5
+- Code(Counter(0)) at (prev + 41, 1) to (start + 0, 34)
+- Code(Counter(1)) at (prev + 1, 9) to (start + 0, 10)
+- Code(Expression(0, Add)) at (prev + 0, 14) to (start + 0, 16)
+    = (c0 + c1)
+- Code(Expression(1, Add)) at (prev + 0, 17) to (start + 2, 6)
+    = (c1 + Zero)
+- Code(Expression(2, Sub)) at (prev + 3, 5) to (start + 1, 2)
+    = ((c0 + c1) - c1)
+
+Function name: inline::error
+Raw bytes (9): 0x[01, 01, 00, 01, 01, 31, 01, 02, 02]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 0
+Number of file 0 mappings: 1
+- Code(Counter(0)) at (prev + 49, 1) to (start + 2, 2)
+
+Function name: inline::length::<char>
+Raw bytes (9): 0x[01, 01, 00, 01, 01, 1e, 01, 02, 02]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 0
+Number of file 0 mappings: 1
+- Code(Counter(0)) at (prev + 30, 1) to (start + 2, 2)
+
+Function name: inline::main
+Raw bytes (9): 0x[01, 01, 00, 01, 01, 05, 01, 02, 02]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 0
+Number of file 0 mappings: 1
+- Code(Counter(0)) at (prev + 5, 1) to (start + 2, 2)
+
+Function name: inline::permutate::<char>
+Raw bytes (54): 0x[01, 01, 05, 01, 05, 02, 0d, 11, 00, 05, 13, 09, 0d, 08, 01, 0f, 01, 02, 0e, 05, 02, 0f, 02, 06, 02, 02, 0f, 00, 14, 11, 01, 0d, 00, 0e, 06, 00, 12, 00, 16, 0b, 00, 17, 04, 0a, 0d, 05, 0c, 02, 06, 0f, 03, 01, 00, 02]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 5
+- expression 0 operands: lhs = Counter(0), rhs = Counter(1)
+- expression 1 operands: lhs = Expression(0, Sub), rhs = Counter(3)
+- expression 2 operands: lhs = Counter(4), rhs = Zero
+- expression 3 operands: lhs = Counter(1), rhs = Expression(4, Add)
+- expression 4 operands: lhs = Counter(2), rhs = Counter(3)
+Number of file 0 mappings: 8
+- Code(Counter(0)) at (prev + 15, 1) to (start + 2, 14)
+- Code(Counter(1)) at (prev + 2, 15) to (start + 2, 6)
+- Code(Expression(0, Sub)) at (prev + 2, 15) to (start + 0, 20)
+    = (c0 - c1)
+- Code(Counter(4)) at (prev + 1, 13) to (start + 0, 14)
+- Code(Expression(1, Sub)) at (prev + 0, 18) to (start + 0, 22)
+    = ((c0 - c1) - c3)
+- Code(Expression(2, Add)) at (prev + 0, 23) to (start + 4, 10)
+    = (c4 + Zero)
+- Code(Counter(3)) at (prev + 5, 12) to (start + 2, 6)
+- Code(Expression(3, Add)) at (prev + 3, 1) to (start + 0, 2)
+    = (c1 + (c2 + c3))
+
+Function name: inline::permutations::<char>
+Raw bytes (9): 0x[01, 01, 00, 01, 01, 0a, 01, 03, 02]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 0
+Number of file 0 mappings: 1
+- Code(Counter(0)) at (prev + 10, 1) to (start + 3, 2)
+
+Function name: inline::swap::<char>
+Raw bytes (9): 0x[01, 01, 00, 01, 01, 23, 01, 04, 02]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 0
+Number of file 0 mappings: 1
+- Code(Counter(0)) at (prev + 35, 1) to (start + 4, 2)
+

tests/coverage-map/status-quo/inline.rs

@@ -0,0 +1,51 @@
+// compile-flags: -Zinline-mir
+
+use std::fmt::Display;
+
+fn main() {
+    permutations(&['a', 'b', 'c']);
+}
+
+#[inline(always)]
+fn permutations<T: Copy + Display>(xs: &[T]) {
+    let mut ys = xs.to_owned();
+    permutate(&mut ys, 0);
+}
+
+fn permutate<T: Copy + Display>(xs: &mut [T], k: usize) {
+    let n = length(xs);
+    if k == n {
+        display(xs);
+    } else if k < n {
+        for i in k..n {
+            swap(xs, i, k);
+            permutate(xs, k + 1);
+            swap(xs, i, k);
+        }
+    } else {
+        error();
+    }
+}
+
+fn length<T>(xs: &[T]) -> usize {
+    xs.len()
+}
+
+#[inline]
+fn swap<T: Copy>(xs: &mut [T], i: usize, j: usize) {
+    let t = xs[i];
+    xs[i] = xs[j];
+    xs[j] = t;
+}
+
+fn display<T: Display>(xs: &[T]) {
+    for x in xs {
+        print!("{}", x);
+    }
+    println!();
+}
+
+#[inline(always)]
+fn error() {
+    panic!("error");
+}

tests/coverage-map/status-quo/inner_items.cov-map

@@ -0,0 +1,49 @@
+Function name: <inner_items::main::InStruct as inner_items::main::InTrait>::default_trait_func
+Raw bytes (9): 0x[01, 01, 00, 01, 01, 21, 09, 03, 0a]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 0
+Number of file 0 mappings: 1
+- Code(Counter(0)) at (prev + 33, 9) to (start + 3, 10)
+
+Function name: <inner_items::main::InStruct as inner_items::main::InTrait>::trait_func
+Raw bytes (9): 0x[01, 01, 00, 01, 01, 28, 09, 03, 0a]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 0
+Number of file 0 mappings: 1
+- Code(Counter(0)) at (prev + 40, 9) to (start + 3, 10)
+
+Function name: inner_items::main
+Raw bytes (53): 0x[01, 01, 07, 01, 05, 05, 02, 1b, 09, 05, 02, 09, 16, 1b, 09, 05, 02, 07, 01, 03, 01, 07, 0f, 05, 07, 10, 02, 06, 02, 02, 06, 00, 07, 1b, 24, 08, 00, 0f, 09, 00, 10, 02, 06, 16, 02, 06, 00, 07, 13, 02, 09, 05, 02]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 7
+- expression 0 operands: lhs = Counter(0), rhs = Counter(1)
+- expression 1 operands: lhs = Counter(1), rhs = Expression(0, Sub)
+- expression 2 operands: lhs = Expression(6, Add), rhs = Counter(2)
+- expression 3 operands: lhs = Counter(1), rhs = Expression(0, Sub)
+- expression 4 operands: lhs = Counter(2), rhs = Expression(5, Sub)
+- expression 5 operands: lhs = Expression(6, Add), rhs = Counter(2)
+- expression 6 operands: lhs = Counter(1), rhs = Expression(0, Sub)
+Number of file 0 mappings: 7
+- Code(Counter(0)) at (prev + 3, 1) to (start + 7, 15)
+- Code(Counter(1)) at (prev + 7, 16) to (start + 2, 6)
+- Code(Expression(0, Sub)) at (prev + 2, 6) to (start + 0, 7)
+    = (c0 - c1)
+- Code(Expression(6, Add)) at (prev + 36, 8) to (start + 0, 15)
+    = (c1 + (c0 - c1))
+- Code(Counter(2)) at (prev + 0, 16) to (start + 2, 6)
+- Code(Expression(5, Sub)) at (prev + 2, 6) to (start + 0, 7)
+    = ((c1 + (c0 - c1)) - c2)
+- Code(Expression(4, Add)) at (prev + 2, 9) to (start + 5, 2)
+    = (c2 + ((c1 + (c0 - c1)) - c2))
+
+Function name: inner_items::main::in_func
+Raw bytes (9): 0x[01, 01, 00, 01, 01, 12, 05, 04, 06]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 0
+Number of file 0 mappings: 1
+- Code(Counter(0)) at (prev + 18, 5) to (start + 4, 6)
+

tests/coverage-map/status-quo/inner_items.rs

@@ -0,0 +1,57 @@
+#![allow(unused_assignments, unused_variables, dead_code)]
+
+fn main() {
+    // Initialize test constants in a way that cannot be determined at compile time, to ensure
+    // rustc and LLVM cannot optimize out statements (or coverage counters) downstream from
+    // dependent conditions.
+    let is_true = std::env::args().len() == 1;
+
+    let mut countdown = 0;
+    if is_true {
+        countdown = 10;
+    }
+
+    mod in_mod {
+        const IN_MOD_CONST: u32 = 1000;
+    }
+
+    fn in_func(a: u32) {
+        let b = 1;
+        let c = a + b;
+        println!("c = {}", c)
+    }
+
+    struct InStruct {
+        in_struct_field: u32,
+    }
+
+    const IN_CONST: u32 = 1234;
+
+    trait InTrait {
+        fn trait_func(&mut self, incr: u32);
+
+        fn default_trait_func(&mut self) {
+            in_func(IN_CONST);
+            self.trait_func(IN_CONST);
+        }
+    }
+
+    impl InTrait for InStruct {
+        fn trait_func(&mut self, incr: u32) {
+            self.in_struct_field += incr;
+            in_func(self.in_struct_field);
+        }
+    }
+
+    type InType = String;
+
+    if is_true {
+        in_func(countdown);
+    }
+
+    let mut val = InStruct {
+        in_struct_field: 101,
+    };
+
+    val.default_trait_func();
+}

tests/coverage-map/status-quo/issue-83601.cov-map

@@ -0,0 +1,28 @@
+Function name: <issue_83601::Foo as core::cmp::PartialEq>::eq
+Raw bytes (9): 0x[01, 01, 00, 01, 01, 03, 11, 00, 1a]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 0
+Number of file 0 mappings: 1
+- Code(Counter(0)) at (prev + 3, 17) to (start + 0, 26)
+
+Function name: <issue_83601::Foo as core::fmt::Debug>::fmt
+Raw bytes (9): 0x[01, 01, 00, 01, 01, 03, 0a, 00, 0f]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 0
+Number of file 0 mappings: 1
+- Code(Counter(0)) at (prev + 3, 10) to (start + 0, 15)
+
+Function name: issue_83601::main
+Raw bytes (21): 0x[01, 01, 01, 05, 09, 03, 01, 06, 01, 02, 1c, 05, 03, 09, 01, 1c, 02, 02, 05, 03, 02]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 1
+- expression 0 operands: lhs = Counter(1), rhs = Counter(2)
+Number of file 0 mappings: 3
+- Code(Counter(0)) at (prev + 6, 1) to (start + 2, 28)
+- Code(Counter(1)) at (prev + 3, 9) to (start + 1, 28)
+- Code(Expression(0, Sub)) at (prev + 2, 5) to (start + 3, 2)
+    = (c1 - c2)
+

tests/coverage-map/status-quo/issue-83601.rs

@@ -0,0 +1,14 @@
+// Shows that rust-lang/rust/83601 is resolved
+
+#[derive(Debug, PartialEq, Eq)]
+struct Foo(u32);
+
+fn main() {
+    let bar = Foo(1);
+    assert_eq!(bar, Foo(1));
+    let baz = Foo(0);
+    assert_ne!(baz, Foo(1));
+    println!("{:?}", Foo(1));
+    println!("{:?}", bar);
+    println!("{:?}", baz);
+}

tests/coverage-map/status-quo/issue-84561.cov-map

@@ -0,0 +1,233 @@
+Function name: <issue_84561::Foo as core::cmp::PartialEq>::eq
+Raw bytes (14): 0x[01, 01, 00, 02, 01, 04, 0a, 00, 13, 00, 00, 0a, 00, 13]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 0
+Number of file 0 mappings: 2
+- Code(Counter(0)) at (prev + 4, 10) to (start + 0, 19)
+- Code(Zero) at (prev + 0, 10) to (start + 0, 19)
+
+Function name: <issue_84561::Foo as core::fmt::Debug>::fmt
+Raw bytes (29): 0x[01, 01, 02, 01, 05, 05, 02, 04, 01, 89, 01, 09, 00, 25, 05, 00, 25, 00, 26, 02, 01, 09, 00, 0f, 07, 01, 05, 00, 06]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 2
+- expression 0 operands: lhs = Counter(0), rhs = Counter(1)
+- expression 1 operands: lhs = Counter(1), rhs = Expression(0, Sub)
+Number of file 0 mappings: 4
+- Code(Counter(0)) at (prev + 137, 9) to (start + 0, 37)
+- Code(Counter(1)) at (prev + 0, 37) to (start + 0, 38)
+- Code(Expression(0, Sub)) at (prev + 1, 9) to (start + 0, 15)
+    = (c0 - c1)
+- Code(Expression(1, Add)) at (prev + 1, 5) to (start + 0, 6)
+    = (c1 + (c0 - c1))
+
+Function name: issue_84561::main
+Raw bytes (10): 0x[01, 01, 00, 01, 01, b2, 01, 01, 04, 02]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 0
+Number of file 0 mappings: 1
+- Code(Counter(0)) at (prev + 178, 1) to (start + 4, 2)
+
+Function name: issue_84561::test1
+Raw bytes (78): 0x[01, 01, 0e, 05, 06, 01, 05, 09, 36, 03, 09, 0d, 2e, 33, 0d, 09, 36, 03, 09, 11, 26, 2b, 11, 0d, 2e, 33, 0d, 09, 36, 03, 09, 09, 01, 98, 01, 01, 01, 0b, 05, 01, 0c, 00, 1e, 03, 01, 05, 00, 0b, 09, 00, 0c, 00, 1e, 33, 01, 0d, 01, 0b, 0d, 01, 0c, 00, 1e, 2b, 01, 05, 03, 0b, 11, 03, 0c, 00, 1e, 23, 01, 01, 00, 02]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 14
+- expression 0 operands: lhs = Counter(1), rhs = Expression(1, Sub)
+- expression 1 operands: lhs = Counter(0), rhs = Counter(1)
+- expression 2 operands: lhs = Counter(2), rhs = Expression(13, Sub)
+- expression 3 operands: lhs = Expression(0, Add), rhs = Counter(2)
+- expression 4 operands: lhs = Counter(3), rhs = Expression(11, Sub)
+- expression 5 operands: lhs = Expression(12, Add), rhs = Counter(3)
+- expression 6 operands: lhs = Counter(2), rhs = Expression(13, Sub)
+- expression 7 operands: lhs = Expression(0, Add), rhs = Counter(2)
+- expression 8 operands: lhs = Counter(4), rhs = Expression(9, Sub)
+- expression 9 operands: lhs = Expression(10, Add), rhs = Counter(4)
+- expression 10 operands: lhs = Counter(3), rhs = Expression(11, Sub)
+- expression 11 operands: lhs = Expression(12, Add), rhs = Counter(3)
+- expression 12 operands: lhs = Counter(2), rhs = Expression(13, Sub)
+- expression 13 operands: lhs = Expression(0, Add), rhs = Counter(2)
+Number of file 0 mappings: 9
+- Code(Counter(0)) at (prev + 152, 1) to (start + 1, 11)
+- Code(Counter(1)) at (prev + 1, 12) to (start + 0, 30)
+- Code(Expression(0, Add)) at (prev + 1, 5) to (start + 0, 11)
+    = (c1 + (c0 - c1))
+- Code(Counter(2)) at (prev + 0, 12) to (start + 0, 30)
+- Code(Expression(12, Add)) at (prev + 1, 13) to (start + 1, 11)
+    = (c2 + ((c1 + (c0 - c1)) - c2))
+- Code(Counter(3)) at (prev + 1, 12) to (start + 0, 30)
+- Code(Expression(10, Add)) at (prev + 1, 5) to (start + 3, 11)
+    = (c3 + ((c2 + ((c1 + (c0 - c1)) - c2)) - c3))
+- Code(Counter(4)) at (prev + 3, 12) to (start + 0, 30)
+- Code(Expression(8, Add)) at (prev + 1, 1) to (start + 0, 2)
+    = (c4 + ((c3 + ((c2 + ((c1 + (c0 - c1)) - c2)) - c3)) - c4))
+
+Function name: issue_84561::test2
+Raw bytes (24): 0x[01, 01, 02, 05, 06, 01, 05, 03, 01, ae, 01, 01, 01, 10, 05, 01, 11, 00, 23, 03, 01, 01, 00, 02]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 2
+- expression 0 operands: lhs = Counter(1), rhs = Expression(1, Sub)
+- expression 1 operands: lhs = Counter(0), rhs = Counter(1)
+Number of file 0 mappings: 3
+- Code(Counter(0)) at (prev + 174, 1) to (start + 1, 16)
+- Code(Counter(1)) at (prev + 1, 17) to (start + 0, 35)
+- Code(Expression(0, Add)) at (prev + 1, 1) to (start + 0, 2)
+    = (c1 + (c0 - c1))
+
+Function name: issue_84561::test2::call_print
+Raw bytes (10): 0x[01, 01, 00, 01, 01, a5, 01, 09, 02, 0a]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 0
+Number of file 0 mappings: 1
+- Code(Counter(0)) at (prev + 165, 9) to (start + 2, 10)
+
+Function name: issue_84561::test3
+Raw bytes (437): 0x[01, 01, 41, 05, 09, 0d, 11, 15, 19, 12, 1d, 15, 19, 21, 25, 1e, 29, 21, 25, 31, 39, 3d, 41, 2e, 45, 3d, 41, 42, 49, 45, 4d, 3f, 51, 42, 49, 45, 4d, 5d, 8a, 01, 8f, 01, 5d, 92, 01, 55, 51, 59, 92, 01, 55, 51, 59, 8f, 01, 5d, 92, 01, 55, 51, 59, 87, 01, 61, 5d, 8a, 01, 8f, 01, 5d, 92, 01, 55, 51, 59, 82, 01, 65, 87, 01, 61, 5d, 8a, 01, 8f, 01, 5d, 92, 01, 55, 51, 59, 75, f6, 01, fb, 01, 79, 71, fe, 01, 82, 02, 71, 69, 6d, 71, fe, 01, 82, 02, 71, 69, 6d, 69, 6d, 82, 02, 71, 69, 6d, fb, 01, 79, 71, fe, 01, 82, 02, 71, 69, 6d, f3, 01, 7d, 75, f6, 01, fb, 01, 79, 71, fe, 01, 82, 02, 71, 69, 6d, ee, 01, 81, 01, f3, 01, 7d, 75, f6, 01, fb, 01, 79, 71, fe, 01, 82, 02, 71, 69, 6d, 33, 01, 06, 01, 03, 1c, 05, 04, 09, 01, 1c, 02, 02, 05, 04, 1f, 0d, 05, 05, 00, 1f, 06, 01, 05, 00, 1f, 15, 01, 09, 01, 1c, 12, 02, 05, 00, 1f, 0e, 01, 05, 00, 0f, 00, 00, 20, 00, 30, 21, 01, 05, 03, 0f, 00, 03, 20, 00, 30, 00, 00, 33, 00, 41, 00, 00, 4b, 00, 5a, 1e, 01, 05, 00, 0f, 00, 05, 09, 03, 10, 00, 05, 0d, 00, 1b, 00, 02, 0d, 00, 1c, 1a, 04, 09, 05, 06, 31, 06, 05, 03, 06, 22, 04, 05, 03, 06, 3d, 04, 09, 04, 06, 2e, 05, 08, 00, 0f, 45, 01, 09, 03, 0a, 2a, 05, 09, 03, 0a, 3f, 05, 08, 00, 0f, 51, 01, 09, 00, 13, 00, 03, 0d, 00, 1d, 3a, 03, 09, 00, 13, 00, 03, 0d, 00, 1d, 87, 01, 03, 05, 00, 0f, 8f, 01, 01, 0c, 00, 13, 5d, 01, 0d, 00, 13, 8a, 01, 02, 0d, 00, 13, 82, 01, 04, 05, 02, 13, 65, 03, 0d, 00, 13, 7e, 02, 0d, 00, 13, f3, 01, 03, 05, 00, 0f, 69, 01, 0c, 00, 13, 6d, 01, 0d, 03, 0e, 75, 04, 0d, 00, 13, fb, 01, 02, 0d, 00, 17, 82, 02, 01, 14, 00, 1b, 71, 01, 15, 00, 1b, fe, 01, 02, 15, 00, 1b, f6, 01, 04, 0d, 00, 13, 7d, 03, 09, 00, 19, ee, 01, 02, 05, 00, 0f, ea, 01, 03, 09, 00, 22, 00, 02, 05, 00, 0f, 00, 03, 09, 00, 2c, 00, 02, 01, 00, 02]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 65
+- expression 0 operands: lhs = Counter(1), rhs = Counter(2)
+- expression 1 operands: lhs = Counter(3), rhs = Counter(4)
+- expression 2 operands: lhs = Counter(5), rhs = Counter(6)
+- expression 3 operands: lhs = Expression(4, Sub), rhs = Counter(7)
+- expression 4 operands: lhs = Counter(5), rhs = Counter(6)
+- expression 5 operands: lhs = Counter(8), rhs = Counter(9)
+- expression 6 operands: lhs = Expression(7, Sub), rhs = Counter(10)
+- expression 7 operands: lhs = Counter(8), rhs = Counter(9)
+- expression 8 operands: lhs = Counter(12), rhs = Counter(14)
+- expression 9 operands: lhs = Counter(15), rhs = Counter(16)
+- expression 10 operands: lhs = Expression(11, Sub), rhs = Counter(17)
+- expression 11 operands: lhs = Counter(15), rhs = Counter(16)
+- expression 12 operands: lhs = Expression(16, Sub), rhs = Counter(18)
+- expression 13 operands: lhs = Counter(17), rhs = Counter(19)
+- expression 14 operands: lhs = Expression(15, Add), rhs = Counter(20)
+- expression 15 operands: lhs = Expression(16, Sub), rhs = Counter(18)
+- expression 16 operands: lhs = Counter(17), rhs = Counter(19)
+- expression 17 operands: lhs = Counter(23), rhs = Expression(34, Sub)
+- expression 18 operands: lhs = Expression(35, Add), rhs = Counter(23)
+- expression 19 operands: lhs = Expression(36, Sub), rhs = Counter(21)
+- expression 20 operands: lhs = Counter(20), rhs = Counter(22)
+- expression 21 operands: lhs = Expression(36, Sub), rhs = Counter(21)
+- expression 22 operands: lhs = Counter(20), rhs = Counter(22)
+- expression 23 operands: lhs = Expression(35, Add), rhs = Counter(23)
+- expression 24 operands: lhs = Expression(36, Sub), rhs = Counter(21)
+- expression 25 operands: lhs = Counter(20), rhs = Counter(22)
+- expression 26 operands: lhs = Expression(33, Add), rhs = Counter(24)
+- expression 27 operands: lhs = Counter(23), rhs = Expression(34, Sub)
+- expression 28 operands: lhs = Expression(35, Add), rhs = Counter(23)
+- expression 29 operands: lhs = Expression(36, Sub), rhs = Counter(21)
+- expression 30 operands: lhs = Counter(20), rhs = Counter(22)
+- expression 31 operands: lhs = Expression(32, Sub), rhs = Counter(25)
+- expression 32 operands: lhs = Expression(33, Add), rhs = Counter(24)
+- expression 33 operands: lhs = Counter(23), rhs = Expression(34, Sub)
+- expression 34 operands: lhs = Expression(35, Add), rhs = Counter(23)
+- expression 35 operands: lhs = Expression(36, Sub), rhs = Counter(21)
+- expression 36 operands: lhs = Counter(20), rhs = Counter(22)
+- expression 37 operands: lhs = Counter(29), rhs = Expression(61, Sub)
+- expression 38 operands: lhs = Expression(62, Add), rhs = Counter(30)
+- expression 39 operands: lhs = Counter(28), rhs = Expression(63, Sub)
+- expression 40 operands: lhs = Expression(64, Sub), rhs = Counter(28)
+- expression 41 operands: lhs = Counter(26), rhs = Counter(27)
+- expression 42 operands: lhs = Counter(28), rhs = Expression(63, Sub)
+- expression 43 operands: lhs = Expression(64, Sub), rhs = Counter(28)
+- expression 44 operands: lhs = Counter(26), rhs = Counter(27)
+- expression 45 operands: lhs = Counter(26), rhs = Counter(27)
+- expression 46 operands: lhs = Expression(64, Sub), rhs = Counter(28)
+- expression 47 operands: lhs = Counter(26), rhs = Counter(27)
+- expression 48 operands: lhs = Expression(62, Add), rhs = Counter(30)
+- expression 49 operands: lhs = Counter(28), rhs = Expression(63, Sub)
+- expression 50 operands: lhs = Expression(64, Sub), rhs = Counter(28)
+- expression 51 operands: lhs = Counter(26), rhs = Counter(27)
+- expression 52 operands: lhs = Expression(60, Add), rhs = Counter(31)
+- expression 53 operands: lhs = Counter(29), rhs = Expression(61, Sub)
+- expression 54 operands: lhs = Expression(62, Add), rhs = Counter(30)
+- expression 55 operands: lhs = Counter(28), rhs = Expression(63, Sub)
+- expression 56 operands: lhs = Expression(64, Sub), rhs = Counter(28)
+- expression 57 operands: lhs = Counter(26), rhs = Counter(27)
+- expression 58 operands: lhs = Expression(59, Sub), rhs = Counter(32)
+- expression 59 operands: lhs = Expression(60, Add), rhs = Counter(31)
+- expression 60 operands: lhs = Counter(29), rhs = Expression(61, Sub)
+- expression 61 operands: lhs = Expression(62, Add), rhs = Counter(30)
+- expression 62 operands: lhs = Counter(28), rhs = Expression(63, Sub)
+- expression 63 operands: lhs = Expression(64, Sub), rhs = Counter(28)
+- expression 64 operands: lhs = Counter(26), rhs = Counter(27)
+Number of file 0 mappings: 51
+- Code(Counter(0)) at (prev + 6, 1) to (start + 3, 28)
+- Code(Counter(1)) at (prev + 4, 9) to (start + 1, 28)
+- Code(Expression(0, Sub)) at (prev + 2, 5) to (start + 4, 31)
+    = (c1 - c2)
+- Code(Counter(3)) at (prev + 5, 5) to (start + 0, 31)
+- Code(Expression(1, Sub)) at (prev + 1, 5) to (start + 0, 31)
+    = (c3 - c4)
+- Code(Counter(5)) at (prev + 1, 9) to (start + 1, 28)
+- Code(Expression(4, Sub)) at (prev + 2, 5) to (start + 0, 31)
+    = (c5 - c6)
+- Code(Expression(3, Sub)) at (prev + 1, 5) to (start + 0, 15)
+    = ((c5 - c6) - c7)
+- Code(Zero) at (prev + 0, 32) to (start + 0, 48)
+- Code(Counter(8)) at (prev + 1, 5) to (start + 3, 15)
+- Code(Zero) at (prev + 3, 32) to (start + 0, 48)
+- Code(Zero) at (prev + 0, 51) to (start + 0, 65)
+- Code(Zero) at (prev + 0, 75) to (start + 0, 90)
+- Code(Expression(7, Sub)) at (prev + 1, 5) to (start + 0, 15)
+    = (c8 - c9)
+- Code(Zero) at (prev + 5, 9) to (start + 3, 16)
+- Code(Zero) at (prev + 5, 13) to (start + 0, 27)
+- Code(Zero) at (prev + 2, 13) to (start + 0, 28)
+- Code(Expression(6, Sub)) at (prev + 4, 9) to (start + 5, 6)
+    = ((c8 - c9) - c10)
+- Code(Counter(12)) at (prev + 6, 5) to (start + 3, 6)
+- Code(Expression(8, Sub)) at (prev + 4, 5) to (start + 3, 6)
+    = (c12 - c14)
+- Code(Counter(15)) at (prev + 4, 9) to (start + 4, 6)
+- Code(Expression(11, Sub)) at (prev + 5, 8) to (start + 0, 15)
+    = (c15 - c16)
+- Code(Counter(17)) at (prev + 1, 9) to (start + 3, 10)
+- Code(Expression(10, Sub)) at (prev + 5, 9) to (start + 3, 10)
+    = ((c15 - c16) - c17)
+- Code(Expression(15, Add)) at (prev + 5, 8) to (start + 0, 15)
+    = ((c17 - c19) + c18)
+- Code(Counter(20)) at (prev + 1, 9) to (start + 0, 19)
+- Code(Zero) at (prev + 3, 13) to (start + 0, 29)
+- Code(Expression(14, Sub)) at (prev + 3, 9) to (start + 0, 19)
+    = (((c17 - c19) + c18) - c20)
+- Code(Zero) at (prev + 3, 13) to (start + 0, 29)
+- Code(Expression(33, Add)) at (prev + 3, 5) to (start + 0, 15)
+    = (c23 + (((c20 - c22) + c21) - c23))
+- Code(Expression(35, Add)) at (prev + 1, 12) to (start + 0, 19)
+    = ((c20 - c22) + c21)
+- Code(Counter(23)) at (prev + 1, 13) to (start + 0, 19)
+- Code(Expression(34, Sub)) at (prev + 2, 13) to (start + 0, 19)
+    = (((c20 - c22) + c21) - c23)
+- Code(Expression(32, Sub)) at (prev + 4, 5) to (start + 2, 19)
+    = ((c23 + (((c20 - c22) + c21) - c23)) - c24)
+- Code(Counter(25)) at (prev + 3, 13) to (start + 0, 19)
+- Code(Expression(31, Sub)) at (prev + 2, 13) to (start + 0, 19)
+    = (((c23 + (((c20 - c22) + c21) - c23)) - c24) - c25)
+- Code(Expression(60, Add)) at (prev + 3, 5) to (start + 0, 15)
+    = (c29 + ((c28 + ((c26 - c27) - c28)) - c30))
+- Code(Counter(26)) at (prev + 1, 12) to (start + 0, 19)
+- Code(Counter(27)) at (prev + 1, 13) to (start + 3, 14)
+- Code(Counter(29)) at (prev + 4, 13) to (start + 0, 19)
+- Code(Expression(62, Add)) at (prev + 2, 13) to (start + 0, 23)
+    = (c28 + ((c26 - c27) - c28))
+- Code(Expression(64, Sub)) at (prev + 1, 20) to (start + 0, 27)
+    = (c26 - c27)
+- Code(Counter(28)) at (prev + 1, 21) to (start + 0, 27)
+- Code(Expression(63, Sub)) at (prev + 2, 21) to (start + 0, 27)
+    = ((c26 - c27) - c28)
+- Code(Expression(61, Sub)) at (prev + 4, 13) to (start + 0, 19)
+    = ((c28 + ((c26 - c27) - c28)) - c30)
+- Code(Counter(31)) at (prev + 3, 9) to (start + 0, 25)
+- Code(Expression(59, Sub)) at (prev + 2, 5) to (start + 0, 15)
+    = ((c29 + ((c28 + ((c26 - c27) - c28)) - c30)) - c31)
+- Code(Expression(58, Sub)) at (prev + 3, 9) to (start + 0, 34)
+    = (((c29 + ((c28 + ((c26 - c27) - c28)) - c30)) - c31) - c32)
+- Code(Zero) at (prev + 2, 5) to (start + 0, 15)
+- Code(Zero) at (prev + 3, 9) to (start + 0, 44)
+- Code(Zero) at (prev + 2, 1) to (start + 0, 2)
+

tests/coverage-map/status-quo/issue-84561.rs

@@ -0,0 +1,182 @@
+// This demonstrated Issue #84561: function-like macros produce unintuitive coverage results.
+
+// failure-status: 101
+#[derive(PartialEq, Eq)]
+struct Foo(u32);
+fn test3() {
+    let is_true = std::env::args().len() == 1;
+    let bar = Foo(1);
+    assert_eq!(bar, Foo(1));
+    let baz = Foo(0);
+    assert_ne!(baz, Foo(1));
+    println!("{:?}", Foo(1));
+    println!("{:?}", bar);
+    println!("{:?}", baz);
+
+    assert_eq!(Foo(1), Foo(1));
+    assert_ne!(Foo(0), Foo(1));
+    assert_eq!(Foo(2), Foo(2));
+    let bar = Foo(0);
+    assert_ne!(bar, Foo(3));
+    assert_ne!(Foo(0), Foo(4));
+    assert_eq!(Foo(3), Foo(3), "with a message");
+    println!("{:?}", bar);
+    println!("{:?}", Foo(1));
+
+    assert_ne!(Foo(0), Foo(5), "{}", if is_true { "true message" } else { "false message" });
+    assert_ne!(
+        Foo(0)
+        ,
+        Foo(5)
+        ,
+        "{}"
+        ,
+        if
+        is_true
+        {
+            "true message"
+        } else {
+            "false message"
+        }
+    );
+
+    let is_true = std::env::args().len() == 1;
+
+    assert_eq!(
+        Foo(1),
+        Foo(1)
+    );
+    assert_ne!(
+        Foo(0),
+        Foo(1)
+    );
+    assert_eq!(
+        Foo(2),
+        Foo(2)
+    );
+    let bar = Foo(1);
+    assert_ne!(
+        bar,
+        Foo(3)
+    );
+    if is_true {
+        assert_ne!(
+            Foo(0),
+            Foo(4)
+        );
+    } else {
+        assert_eq!(
+            Foo(3),
+            Foo(3)
+        );
+    }
+    if is_true {
+        assert_ne!(
+            Foo(0),
+            Foo(4),
+            "with a message"
+        );
+    } else {
+        assert_eq!(
+            Foo(3),
+            Foo(3),
+            "with a message"
+        );
+    }
+    assert_ne!(
+        if is_true {
+            Foo(0)
+        } else {
+            Foo(1)
+        },
+        Foo(5)
+    );
+    assert_ne!(
+        Foo(5),
+        if is_true {
+            Foo(0)
+        } else {
+            Foo(1)
+        }
+    );
+    assert_ne!(
+        if is_true {
+            assert_eq!(
+                Foo(3),
+                Foo(3)
+            );
+            Foo(0)
+        } else {
+            assert_ne!(
+                if is_true {
+                    Foo(0)
+                } else {
+                    Foo(1)
+                },
+                Foo(5)
+            );
+            Foo(1)
+        },
+        Foo(5),
+        "with a message"
+    );
+    assert_eq!(
+        Foo(1),
+        Foo(3),
+        "this assert should fail"
+    );
+    assert_eq!(
+        Foo(3),
+        Foo(3),
+        "this assert should not be reached"
+    );
+}
+
+impl std::fmt::Debug for Foo {
+    fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
+        write!(f, "try and succeed")?;
+        Ok(())
+    }
+}
+
+static mut DEBUG_LEVEL_ENABLED: bool = false;
+
+macro_rules! debug {
+    ($($arg:tt)+) => (
+        if unsafe { DEBUG_LEVEL_ENABLED } {
+            println!($($arg)+);
+        }
+    );
+}
+
+fn test1() {
+    debug!("debug is enabled");
+    debug!("debug is enabled");
+    let _ = 0;
+    debug!("debug is enabled");
+    unsafe {
+        DEBUG_LEVEL_ENABLED = true;
+    }
+    debug!("debug is enabled");
+}
+
+macro_rules! call_debug {
+    ($($arg:tt)+) => (
+        fn call_print(s: &str) {
+            print!("{}", s);
+        }
+
+        call_print("called from call_debug: ");
+        debug!($($arg)+);
+    );
+}
+
+fn test2() {
+    call_debug!("debug is enabled");
+}
+
+fn main() {
+    test1();
+    test2();
+    test3();
+}

tests/coverage-map/status-quo/issue-93054.cov-map

@@ -0,0 +1,24 @@
+Function name: issue_93054::foo2 (unused)
+Raw bytes (9): 0x[01, 01, 00, 01, 01, 16, 01, 00, 1d]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 0
+Number of file 0 mappings: 1
+- Code(Counter(0)) at (prev + 22, 1) to (start + 0, 29)
+
+Function name: issue_93054::main
+Raw bytes (9): 0x[01, 01, 00, 01, 01, 1e, 01, 00, 0d]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 0
+Number of file 0 mappings: 1
+- Code(Counter(0)) at (prev + 30, 1) to (start + 0, 13)
+
+Function name: issue_93054::make (unused)
+Raw bytes (9): 0x[01, 01, 00, 01, 01, 1a, 01, 02, 02]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 0
+Number of file 0 mappings: 1
+- Code(Counter(0)) at (prev + 26, 1) to (start + 2, 2)
+

tests/coverage-map/status-quo/issue-93054.rs

@@ -0,0 +1,30 @@
+#![allow(dead_code, unreachable_code)]
+
+// Regression test for #93054: Functions using uninhabited types often only have a single,
+// unreachable basic block which doesn't get instrumented. This should not cause llvm-cov to fail.
+// Since these kinds functions can't be invoked anyway, it's ok to not have coverage data for them.
+
+// compile-flags: --edition=2021
+
+enum Never {}
+
+impl Never {
+    fn foo(self) {
+        match self {}
+        make().map(|never| match never {});
+    }
+
+    fn bar(&self) {
+        match *self {}
+    }
+}
+
+async fn foo2(never: Never) {
+    match never {}
+}
+
+fn make() -> Option<Never> {
+    None
+}
+
+fn main() {}

tests/coverage-map/status-quo/lazy_boolean.cov-map

@@ -0,0 +1,223 @@
+Function name: lazy_boolean::main
+Raw bytes (646): 0x[01, 01, a8, 01, 01, 05, 09, 9a, 05, 9f, 05, 09, 05, 02, 05, 02, 9f, 05, 09, 05, 02, 0d, 92, 05, 97, 05, 0d, 09, 9a, 05, 9f, 05, 09, 05, 02, 97, 05, 00, 09, 9a, 05, 9f, 05, 09, 05, 02, 97, 05, 0d, 09, 9a, 05, 9f, 05, 09, 05, 02, 11, 8a, 05, 8f, 05, 11, 0d, 92, 05, 97, 05, 0d, 09, 9a, 05, 9f, 05, 09, 05, 02, 8f, 05, 00, 0d, 92, 05, 97, 05, 0d, 09, 9a, 05, 9f, 05, 09, 05, 02, 15, 82, 05, 87, 05, 15, 11, 8a, 05, 8f, 05, 11, 0d, 92, 05, 97, 05, 0d, 09, 9a, 05, 9f, 05, 09, 05, 02, 87, 05, 00, 11, 8a, 05, 8f, 05, 11, 0d, 92, 05, 97, 05, 0d, 09, 9a, 05, 9f, 05, 09, 05, 02, ff, 04, 00, 15, 82, 05, 87, 05, 15, 11, 8a, 05, 8f, 05, 11, 0d, 92, 05, 97, 05, 0d, 09, 9a, 05, 9f, 05, 09, 05, 02, ff, 04, 19, 15, 82, 05, 87, 05, 15, 11, 8a, 05, 8f, 05, 11, 0d, 92, 05, 97, 05, 0d, 09, 9a, 05, 9f, 05, 09, 05, 02, 19, fa, 04, ff, 04, 19, 15, 82, 05, 87, 05, 15, 11, 8a, 05, 8f, 05, 11, 0d, 92, 05, 97, 05, 0d, 09, 9a, 05, 9f, 05, 09, 05, 02, f7, 04, 1d, 19, fa, 04, ff, 04, 19, 15, 82, 05, 87, 05, 15, 11, 8a, 05, 8f, 05, 11, 0d, 92, 05, 97, 05, 0d, 09, 9a, 05, 9f, 05, 09, 05, 02, 1d, f2, 04, f7, 04, 1d, 19, fa, 04, ff, 04, 19, 15, 82, 05, 87, 05, 15, 11, 8a, 05, 8f, 05, 11, 0d, 92, 05, 97, 05, 0d, 09, 9a, 05, 9f, 05, 09, 05, 02, ef, 04, 21, 1d, f2, 04, f7, 04, 1d, 19, fa, 04, ff, 04, 19, 15, 82, 05, 87, 05, 15, 11, 8a, 05, 8f, 05, 11, 0d, 92, 05, 97, 05, 0d, 09, 9a, 05, 9f, 05, 09, 05, 02, 21, ea, 04, ef, 04, 21, 1d, f2, 04, f7, 04, 1d, 19, fa, 04, ff, 04, 19, 15, 82, 05, 87, 05, 15, 11, 8a, 05, 8f, 05, 11, 0d, 92, 05, 97, 05, 0d, 09, 9a, 05, 9f, 05, 09, 05, 02, e7, 04, 25, 21, ea, 04, ef, 04, 21, 1d, f2, 04, f7, 04, 1d, 19, fa, 04, ff, 04, 19, 15, 82, 05, 87, 05, 15, 11, 8a, 05, 8f, 05, 11, 0d, 92, 05, 97, 05, 0d, 09, 9a, 05, 9f, 05, 09, 05, 02, 25, e2, 04, e7, 04, 25, 21, ea, 04, ef, 04, 21, 1d, f2, 04, f7, 04, 1d, 19, fa, 04, ff, 04, 19, 15, 82, 05, 87, 05, 15, 11, 8a, 05, 8f, 05, 11, 0d, 92, 05, 97, 05, 0d, 09, 9a, 05, 9f, 05, 09, 05, 02, 1c, 01, 03, 01, 07, 0f, 05, 07, 10, 04, 06, 02, 04, 06, 00, 07, 97, 05, 02, 09, 00, 11, 9f, 05, 02, 0d, 00, 12, 9a, 05, 02, 0d, 00, 12, 8f, 05, 03, 09, 00, 11, 33, 02, 0d, 00, 12, 92, 05, 02, 0d, 00, 12, 87, 05, 02, 09, 00, 11, 6f, 00, 14, 00, 19, 11, 00, 1d, 00, 22, ff, 04, 01, 09, 00, 11, ab, 01, 00, 14, 00, 19, 15, 00, 1d, 00, 22, cb, 01, 04, 09, 00, 10, fa, 04, 01, 05, 03, 06, 19, 03, 06, 00, 07, f7, 04, 03, 09, 00, 10, 1d, 01, 05, 03, 06, f2, 04, 05, 05, 03, 06, ef, 04, 05, 09, 00, 10, ea, 04, 00, 11, 02, 06, 21, 02, 06, 00, 07, e7, 04, 02, 08, 00, 0f, 25, 00, 10, 02, 06, e2, 04, 02, 0c, 02, 06, df, 04, 03, 01, 00, 02]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 168
+- expression 0 operands: lhs = Counter(0), rhs = Counter(1)
+- expression 1 operands: lhs = Counter(2), rhs = Expression(166, Sub)
+- expression 2 operands: lhs = Expression(167, Add), rhs = Counter(2)
+- expression 3 operands: lhs = Counter(1), rhs = Expression(0, Sub)
+- expression 4 operands: lhs = Counter(1), rhs = Expression(0, Sub)
+- expression 5 operands: lhs = Expression(167, Add), rhs = Counter(2)
+- expression 6 operands: lhs = Counter(1), rhs = Expression(0, Sub)
+- expression 7 operands: lhs = Counter(3), rhs = Expression(164, Sub)
+- expression 8 operands: lhs = Expression(165, Add), rhs = Counter(3)
+- expression 9 operands: lhs = Counter(2), rhs = Expression(166, Sub)
+- expression 10 operands: lhs = Expression(167, Add), rhs = Counter(2)
+- expression 11 operands: lhs = Counter(1), rhs = Expression(0, Sub)
+- expression 12 operands: lhs = Expression(165, Add), rhs = Zero
+- expression 13 operands: lhs = Counter(2), rhs = Expression(166, Sub)
+- expression 14 operands: lhs = Expression(167, Add), rhs = Counter(2)
+- expression 15 operands: lhs = Counter(1), rhs = Expression(0, Sub)
+- expression 16 operands: lhs = Expression(165, Add), rhs = Counter(3)
+- expression 17 operands: lhs = Counter(2), rhs = Expression(166, Sub)
+- expression 18 operands: lhs = Expression(167, Add), rhs = Counter(2)
+- expression 19 operands: lhs = Counter(1), rhs = Expression(0, Sub)
+- expression 20 operands: lhs = Counter(4), rhs = Expression(162, Sub)
+- expression 21 operands: lhs = Expression(163, Add), rhs = Counter(4)
+- expression 22 operands: lhs = Counter(3), rhs = Expression(164, Sub)
+- expression 23 operands: lhs = Expression(165, Add), rhs = Counter(3)
+- expression 24 operands: lhs = Counter(2), rhs = Expression(166, Sub)
+- expression 25 operands: lhs = Expression(167, Add), rhs = Counter(2)
+- expression 26 operands: lhs = Counter(1), rhs = Expression(0, Sub)
+- expression 27 operands: lhs = Expression(163, Add), rhs = Zero
+- expression 28 operands: lhs = Counter(3), rhs = Expression(164, Sub)
+- expression 29 operands: lhs = Expression(165, Add), rhs = Counter(3)
+- expression 30 operands: lhs = Counter(2), rhs = Expression(166, Sub)
+- expression 31 operands: lhs = Expression(167, Add), rhs = Counter(2)
+- expression 32 operands: lhs = Counter(1), rhs = Expression(0, Sub)
+- expression 33 operands: lhs = Counter(5), rhs = Expression(160, Sub)
+- expression 34 operands: lhs = Expression(161, Add), rhs = Counter(5)
+- expression 35 operands: lhs = Counter(4), rhs = Expression(162, Sub)
+- expression 36 operands: lhs = Expression(163, Add), rhs = Counter(4)
+- expression 37 operands: lhs = Counter(3), rhs = Expression(164, Sub)
+- expression 38 operands: lhs = Expression(165, Add), rhs = Counter(3)
+- expression 39 operands: lhs = Counter(2), rhs = Expression(166, Sub)
+- expression 40 operands: lhs = Expression(167, Add), rhs = Counter(2)
+- expression 41 operands: lhs = Counter(1), rhs = Expression(0, Sub)
+- expression 42 operands: lhs = Expression(161, Add), rhs = Zero
+- expression 43 operands: lhs = Counter(4), rhs = Expression(162, Sub)
+- expression 44 operands: lhs = Expression(163, Add), rhs = Counter(4)
+- expression 45 operands: lhs = Counter(3), rhs = Expression(164, Sub)
+- expression 46 operands: lhs = Expression(165, Add), rhs = Counter(3)
+- expression 47 operands: lhs = Counter(2), rhs = Expression(166, Sub)
+- expression 48 operands: lhs = Expression(167, Add), rhs = Counter(2)
+- expression 49 operands: lhs = Counter(1), rhs = Expression(0, Sub)
+- expression 50 operands: lhs = Expression(159, Add), rhs = Zero
+- expression 51 operands: lhs = Counter(5), rhs = Expression(160, Sub)
+- expression 52 operands: lhs = Expression(161, Add), rhs = Counter(5)
+- expression 53 operands: lhs = Counter(4), rhs = Expression(162, Sub)
+- expression 54 operands: lhs = Expression(163, Add), rhs = Counter(4)
+- expression 55 operands: lhs = Counter(3), rhs = Expression(164, Sub)
+- expression 56 operands: lhs = Expression(165, Add), rhs = Counter(3)
+- expression 57 operands: lhs = Counter(2), rhs = Expression(166, Sub)
+- expression 58 operands: lhs = Expression(167, Add), rhs = Counter(2)
+- expression 59 operands: lhs = Counter(1), rhs = Expression(0, Sub)
+- expression 60 operands: lhs = Expression(159, Add), rhs = Counter(6)
+- expression 61 operands: lhs = Counter(5), rhs = Expression(160, Sub)
+- expression 62 operands: lhs = Expression(161, Add), rhs = Counter(5)
+- expression 63 operands: lhs = Counter(4), rhs = Expression(162, Sub)
+- expression 64 operands: lhs = Expression(163, Add), rhs = Counter(4)
+- expression 65 operands: lhs = Counter(3), rhs = Expression(164, Sub)
+- expression 66 operands: lhs = Expression(165, Add), rhs = Counter(3)
+- expression 67 operands: lhs = Counter(2), rhs = Expression(166, Sub)
+- expression 68 operands: lhs = Expression(167, Add), rhs = Counter(2)
+- expression 69 operands: lhs = Counter(1), rhs = Expression(0, Sub)
+- expression 70 operands: lhs = Counter(6), rhs = Expression(158, Sub)
+- expression 71 operands: lhs = Expression(159, Add), rhs = Counter(6)
+- expression 72 operands: lhs = Counter(5), rhs = Expression(160, Sub)
+- expression 73 operands: lhs = Expression(161, Add), rhs = Counter(5)
+- expression 74 operands: lhs = Counter(4), rhs = Expression(162, Sub)
+- expression 75 operands: lhs = Expression(163, Add), rhs = Counter(4)
+- expression 76 operands: lhs = Counter(3), rhs = Expression(164, Sub)
+- expression 77 operands: lhs = Expression(165, Add), rhs = Counter(3)
+- expression 78 operands: lhs = Counter(2), rhs = Expression(166, Sub)
+- expression 79 operands: lhs = Expression(167, Add), rhs = Counter(2)
+- expression 80 operands: lhs = Counter(1), rhs = Expression(0, Sub)
+- expression 81 operands: lhs = Expression(157, Add), rhs = Counter(7)
+- expression 82 operands: lhs = Counter(6), rhs = Expression(158, Sub)
+- expression 83 operands: lhs = Expression(159, Add), rhs = Counter(6)
+- expression 84 operands: lhs = Counter(5), rhs = Expression(160, Sub)
+- expression 85 operands: lhs = Expression(161, Add), rhs = Counter(5)
+- expression 86 operands: lhs = Counter(4), rhs = Expression(162, Sub)
+- expression 87 operands: lhs = Expression(163, Add), rhs = Counter(4)
+- expression 88 operands: lhs = Counter(3), rhs = Expression(164, Sub)
+- expression 89 operands: lhs = Expression(165, Add), rhs = Counter(3)
+- expression 90 operands: lhs = Counter(2), rhs = Expression(166, Sub)
+- expression 91 operands: lhs = Expression(167, Add), rhs = Counter(2)
+- expression 92 operands: lhs = Counter(1), rhs = Expression(0, Sub)
+- expression 93 operands: lhs = Counter(7), rhs = Expression(156, Sub)
+- expression 94 operands: lhs = Expression(157, Add), rhs = Counter(7)
+- expression 95 operands: lhs = Counter(6), rhs = Expression(158, Sub)
+- expression 96 operands: lhs = Expression(159, Add), rhs = Counter(6)
+- expression 97 operands: lhs = Counter(5), rhs = Expression(160, Sub)
+- expression 98 operands: lhs = Expression(161, Add), rhs = Counter(5)
+- expression 99 operands: lhs = Counter(4), rhs = Expression(162, Sub)
+- expression 100 operands: lhs = Expression(163, Add), rhs = Counter(4)
+- expression 101 operands: lhs = Counter(3), rhs = Expression(164, Sub)
+- expression 102 operands: lhs = Expression(165, Add), rhs = Counter(3)
+- expression 103 operands: lhs = Counter(2), rhs = Expression(166, Sub)
+- expression 104 operands: lhs = Expression(167, Add), rhs = Counter(2)
+- expression 105 operands: lhs = Counter(1), rhs = Expression(0, Sub)
+- expression 106 operands: lhs = Expression(155, Add), rhs = Counter(8)
+- expression 107 operands: lhs = Counter(7), rhs = Expression(156, Sub)
+- expression 108 operands: lhs = Expression(157, Add), rhs = Counter(7)
+- expression 109 operands: lhs = Counter(6), rhs = Expression(158, Sub)
+- expression 110 operands: lhs = Expression(159, Add), rhs = Counter(6)
+- expression 111 operands: lhs = Counter(5), rhs = Expression(160, Sub)
+- expression 112 operands: lhs = Expression(161, Add), rhs = Counter(5)
+- expression 113 operands: lhs = Counter(4), rhs = Expression(162, Sub)
+- expression 114 operands: lhs = Expression(163, Add), rhs = Counter(4)
+- expression 115 operands: lhs = Counter(3), rhs = Expression(164, Sub)
+- expression 116 operands: lhs = Expression(165, Add), rhs = Counter(3)
+- expression 117 operands: lhs = Counter(2), rhs = Expression(166, Sub)
+- expression 118 operands: lhs = Expression(167, Add), rhs = Counter(2)
+- expression 119 operands: lhs = Counter(1), rhs = Expression(0, Sub)
+- expression 120 operands: lhs = Counter(8), rhs = Expression(154, Sub)
+- expression 121 operands: lhs = Expression(155, Add), rhs = Counter(8)
+- expression 122 operands: lhs = Counter(7), rhs = Expression(156, Sub)
+- expression 123 operands: lhs = Expression(157, Add), rhs = Counter(7)
+- expression 124 operands: lhs = Counter(6), rhs = Expression(158, Sub)
+- expression 125 operands: lhs = Expression(159, Add), rhs = Counter(6)
+- expression 126 operands: lhs = Counter(5), rhs = Expression(160, Sub)
+- expression 127 operands: lhs = Expression(161, Add), rhs = Counter(5)
+- expression 128 operands: lhs = Counter(4), rhs = Expression(162, Sub)
+- expression 129 operands: lhs = Expression(163, Add), rhs = Counter(4)
+- expression 130 operands: lhs = Counter(3), rhs = Expression(164, Sub)
+- expression 131 operands: lhs = Expression(165, Add), rhs = Counter(3)
+- expression 132 operands: lhs = Counter(2), rhs = Expression(166, Sub)
+- expression 133 operands: lhs = Expression(167, Add), rhs = Counter(2)
+- expression 134 operands: lhs = Counter(1), rhs = Expression(0, Sub)
+- expression 135 operands: lhs = Expression(153, Add), rhs = Counter(9)
+- expression 136 operands: lhs = Counter(8), rhs = Expression(154, Sub)
+- expression 137 operands: lhs = Expression(155, Add), rhs = Counter(8)
+- expression 138 operands: lhs = Counter(7), rhs = Expression(156, Sub)
+- expression 139 operands: lhs = Expression(157, Add), rhs = Counter(7)
+- expression 140 operands: lhs = Counter(6), rhs = Expression(158, Sub)
+- expression 141 operands: lhs = Expression(159, Add), rhs = Counter(6)
+- expression 142 operands: lhs = Counter(5), rhs = Expression(160, Sub)
+- expression 143 operands: lhs = Expression(161, Add), rhs = Counter(5)
+- expression 144 operands: lhs = Counter(4), rhs = Expression(162, Sub)
+- expression 145 operands: lhs = Expression(163, Add), rhs = Counter(4)
+- expression 146 operands: lhs = Counter(3), rhs = Expression(164, Sub)
+- expression 147 operands: lhs = Expression(165, Add), rhs = Counter(3)
+- expression 148 operands: lhs = Counter(2), rhs = Expression(166, Sub)
+- expression 149 operands: lhs = Expression(167, Add), rhs = Counter(2)
+- expression 150 operands: lhs = Counter(1), rhs = Expression(0, Sub)
+- expression 151 operands: lhs = Counter(9), rhs = Expression(152, Sub)
+- expression 152 operands: lhs = Expression(153, Add), rhs = Counter(9)
+- expression 153 operands: lhs = Counter(8), rhs = Expression(154, Sub)
+- expression 154 operands: lhs = Expression(155, Add), rhs = Counter(8)
+- expression 155 operands: lhs = Counter(7), rhs = Expression(156, Sub)
+- expression 156 operands: lhs = Expression(157, Add), rhs = Counter(7)
+- expression 157 operands: lhs = Counter(6), rhs = Expression(158, Sub)
+- expression 158 operands: lhs = Expression(159, Add), rhs = Counter(6)
+- expression 159 operands: lhs = Counter(5), rhs = Expression(160, Sub)
+- expression 160 operands: lhs = Expression(161, Add), rhs = Counter(5)
+- expression 161 operands: lhs = Counter(4), rhs = Expression(162, Sub)
+- expression 162 operands: lhs = Expression(163, Add), rhs = Counter(4)
+- expression 163 operands: lhs = Counter(3), rhs = Expression(164, Sub)
+- expression 164 operands: lhs = Expression(165, Add), rhs = Counter(3)
+- expression 165 operands: lhs = Counter(2), rhs = Expression(166, Sub)
+- expression 166 operands: lhs = Expression(167, Add), rhs = Counter(2)
+- expression 167 operands: lhs = Counter(1), rhs = Expression(0, Sub)
+Number of file 0 mappings: 28
+- Code(Counter(0)) at (prev + 3, 1) to (start + 7, 15)
+- Code(Counter(1)) at (prev + 7, 16) to (start + 4, 6)
+- Code(Expression(0, Sub)) at (prev + 4, 6) to (start + 0, 7)
+    = (c0 - c1)
+- Code(Expression(165, Add)) at (prev + 2, 9) to (start + 0, 17)
+    = (c2 + ((c1 + (c0 - c1)) - c2))
+- Code(Expression(167, Add)) at (prev + 2, 13) to (start + 0, 18)
+    = (c1 + (c0 - c1))
+- Code(Expression(166, Sub)) at (prev + 2, 13) to (start + 0, 18)
+    = ((c1 + (c0 - c1)) - c2)
+- Code(Expression(163, Add)) at (prev + 3, 9) to (start + 0, 17)
+    = (c3 + ((c2 + ((c1 + (c0 - c1)) - c2)) - c3))
+- Code(Expression(12, Add)) at (prev + 2, 13) to (start + 0, 18)
+    = ((c2 + ((c1 + (c0 - c1)) - c2)) + Zero)
+- Code(Expression(164, Sub)) at (prev + 2, 13) to (start + 0, 18)
+    = ((c2 + ((c1 + (c0 - c1)) - c2)) - c3)
+- Code(Expression(161, Add)) at (prev + 2, 9) to (start + 0, 17)
+    = (c4 + ((c3 + ((c2 + ((c1 + (c0 - c1)) - c2)) - c3)) - c4))
+- Code(Expression(27, Add)) at (prev + 0, 20) to (start + 0, 25)
+    = ((c3 + ((c2 + ((c1 + (c0 - c1)) - c2)) - c3)) + Zero)
+- Code(Counter(4)) at (prev + 0, 29) to (start + 0, 34)
+- Code(Expression(159, Add)) at (prev + 1, 9) to (start + 0, 17)
+    = (c5 + ((c4 + ((c3 + ((c2 + ((c1 + (c0 - c1)) - c2)) - c3)) - c4)) - c5))
+- Code(Expression(42, Add)) at (prev + 0, 20) to (start + 0, 25)
+    = ((c4 + ((c3 + ((c2 + ((c1 + (c0 - c1)) - c2)) - c3)) - c4)) + Zero)
+- Code(Counter(5)) at (prev + 0, 29) to (start + 0, 34)
+- Code(Expression(50, Add)) at (prev + 4, 9) to (start + 0, 16)
+    = ((c5 + ((c4 + ((c3 + ((c2 + ((c1 + (c0 - c1)) - c2)) - c3)) - c4)) - c5)) + Zero)
+- Code(Expression(158, Sub)) at (prev + 1, 5) to (start + 3, 6)
+    = ((c5 + ((c4 + ((c3 + ((c2 + ((c1 + (c0 - c1)) - c2)) - c3)) - c4)) - c5)) - c6)
+- Code(Counter(6)) at (prev + 3, 6) to (start + 0, 7)
+- Code(Expression(157, Add)) at (prev + 3, 9) to (start + 0, 16)
+    = (c6 + ((c5 + ((c4 + ((c3 + ((c2 + ((c1 + (c0 - c1)) - c2)) - c3)) - c4)) - c5)) - c6))
+- Code(Counter(7)) at (prev + 1, 5) to (start + 3, 6)
+- Code(Expression(156, Sub)) at (prev + 5, 5) to (start + 3, 6)
+    = ((c6 + ((c5 + ((c4 + ((c3 + ((c2 + ((c1 + (c0 - c1)) - c2)) - c3)) - c4)) - c5)) - c6)) - c7)
+- Code(Expression(155, Add)) at (prev + 5, 9) to (start + 0, 16)
+    = (c7 + ((c6 + ((c5 + ((c4 + ((c3 + ((c2 + ((c1 + (c0 - c1)) - c2)) - c3)) - c4)) - c5)) - c6)) - c7))
+- Code(Expression(154, Sub)) at (prev + 0, 17) to (start + 2, 6)
+    = ((c7 + ((c6 + ((c5 + ((c4 + ((c3 + ((c2 + ((c1 + (c0 - c1)) - c2)) - c3)) - c4)) - c5)) - c6)) - c7)) - c8)
+- Code(Counter(8)) at (prev + 2, 6) to (start + 0, 7)
+- Code(Expression(153, Add)) at (prev + 2, 8) to (start + 0, 15)
+    = (c8 + ((c7 + ((c6 + ((c5 + ((c4 + ((c3 + ((c2 + ((c1 + (c0 - c1)) - c2)) - c3)) - c4)) - c5)) - c6)) - c7)) - c8))
+- Code(Counter(9)) at (prev + 0, 16) to (start + 2, 6)
+- Code(Expression(152, Sub)) at (prev + 2, 12) to (start + 2, 6)
+    = ((c8 + ((c7 + ((c6 + ((c5 + ((c4 + ((c3 + ((c2 + ((c1 + (c0 - c1)) - c2)) - c3)) - c4)) - c5)) - c6)) - c7)) - c8)) - c9)
+- Code(Expression(151, Add)) at (prev + 3, 1) to (start + 0, 2)
+    = (c9 + ((c8 + ((c7 + ((c6 + ((c5 + ((c4 + ((c3 + ((c2 + ((c1 + (c0 - c1)) - c2)) - c3)) - c4)) - c5)) - c6)) - c7)) - c8)) - c9))
+

tests/coverage-map/status-quo/lazy_boolean.rs

@@ -0,0 +1,61 @@
+#![allow(unused_assignments, unused_variables)]
+
+fn main() {
+    // Initialize test constants in a way that cannot be determined at compile time, to ensure
+    // rustc and LLVM cannot optimize out statements (or coverage counters) downstream from
+    // dependent conditions.
+    let is_true = std::env::args().len() == 1;
+
+    let (mut a, mut b, mut c) = (0, 0, 0);
+    if is_true {
+        a = 1;
+        b = 10;
+        c = 100;
+    }
+    let
+        somebool
+        =
+            a < b
+        ||
+            b < c
+    ;
+    let
+        somebool
+        =
+            b < a
+        ||
+            b < c
+    ;
+    let somebool = a < b && b < c;
+    let somebool = b < a && b < c;
+
+    if
+        !
+        is_true
+    {
+        a = 2
+        ;
+    }
+
+    if
+        is_true
+    {
+        b = 30
+        ;
+    }
+    else
+    {
+        c = 400
+        ;
+    }
+
+    if !is_true {
+        a = 2;
+    }
+
+    if is_true {
+        b = 30;
+    } else {
+        c = 400;
+    }
+}

tests/coverage-map/status-quo/loop_break_value.cov-map

@@ -0,0 +1,8 @@
+Function name: loop_break_value::main
+Raw bytes (9): 0x[01, 01, 00, 01, 01, 03, 01, 0a, 02]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 0
+Number of file 0 mappings: 1
+- Code(Counter(0)) at (prev + 3, 1) to (start + 10, 2)
+

tests/coverage-map/status-quo/loop_break_value.rs

@@ -0,0 +1,13 @@
+#![allow(unused_assignments, unused_variables)]
+
+fn main() {
+    let result
+        =
+            loop
+        {
+            break
+            10
+            ;
+        }
+    ;
+}

tests/coverage-map/status-quo/loops_branches.cov-map

@@ -0,0 +1,193 @@
+Function name: <loops_branches::DebugTest as core::fmt::Debug>::fmt
+Raw bytes (262): 0x[01, 01, 36, 05, 09, 0a, 02, 00, 00, cf, 01, 19, d3, 01, d7, 01, 0d, 00, 11, 15, d3, 01, d7, 01, 0d, 00, 11, 15, ca, 01, 00, cf, 01, 19, d3, 01, d7, 01, 0d, 00, 11, 15, ca, 01, 15, cf, 01, 19, d3, 01, d7, 01, 0d, 00, 11, 15, c6, 01, 1d, ca, 01, 15, cf, 01, 19, d3, 01, d7, 01, 0d, 00, 11, 15, be, 01, c2, 01, 00, 00, c6, 01, 1d, ca, 01, 15, cf, 01, 19, d3, 01, d7, 01, 0d, 00, 11, 15, bb, 01, 11, be, 01, c2, 01, 00, 00, c6, 01, 1d, ca, 01, 15, cf, 01, 19, d3, 01, d7, 01, 0d, 00, 11, 15, 25, b3, 01, b6, 01, 19, bb, 01, 11, be, 01, c2, 01, 00, 00, c6, 01, 1d, ca, 01, 15, cf, 01, 19, d3, 01, d7, 01, 0d, 00, 11, 15, 14, 01, 09, 05, 01, 10, 05, 02, 10, 00, 15, 00, 01, 17, 00, 1b, 00, 00, 1c, 00, 1e, 02, 01, 0e, 00, 0f, 07, 01, 0d, 00, 1e, 25, 00, 1e, 00, 1f, 00, 01, 10, 01, 0a, ca, 01, 03, 0d, 00, 0e, cf, 01, 00, 12, 00, 17, 2b, 01, 10, 00, 14, c6, 01, 01, 14, 00, 19, 00, 01, 1b, 00, 1f, 00, 00, 20, 00, 22, c2, 01, 01, 12, 00, 13, bb, 01, 01, 11, 00, 22, b6, 01, 00, 22, 00, 23, 00, 01, 14, 01, 0e, 19, 03, 09, 00, 0f, af, 01, 01, 05, 00, 06]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 54
+- expression 0 operands: lhs = Counter(1), rhs = Counter(2)
+- expression 1 operands: lhs = Expression(2, Sub), rhs = Expression(0, Sub)
+- expression 2 operands: lhs = Zero, rhs = Zero
+- expression 3 operands: lhs = Expression(51, Add), rhs = Counter(6)
+- expression 4 operands: lhs = Expression(52, Add), rhs = Expression(53, Add)
+- expression 5 operands: lhs = Counter(3), rhs = Zero
+- expression 6 operands: lhs = Counter(4), rhs = Counter(5)
+- expression 7 operands: lhs = Expression(52, Add), rhs = Expression(53, Add)
+- expression 8 operands: lhs = Counter(3), rhs = Zero
+- expression 9 operands: lhs = Counter(4), rhs = Counter(5)
+- expression 10 operands: lhs = Expression(50, Sub), rhs = Zero
+- expression 11 operands: lhs = Expression(51, Add), rhs = Counter(6)
+- expression 12 operands: lhs = Expression(52, Add), rhs = Expression(53, Add)
+- expression 13 operands: lhs = Counter(3), rhs = Zero
+- expression 14 operands: lhs = Counter(4), rhs = Counter(5)
+- expression 15 operands: lhs = Expression(50, Sub), rhs = Counter(5)
+- expression 16 operands: lhs = Expression(51, Add), rhs = Counter(6)
+- expression 17 operands: lhs = Expression(52, Add), rhs = Expression(53, Add)
+- expression 18 operands: lhs = Counter(3), rhs = Zero
+- expression 19 operands: lhs = Counter(4), rhs = Counter(5)
+- expression 20 operands: lhs = Expression(49, Sub), rhs = Counter(7)
+- expression 21 operands: lhs = Expression(50, Sub), rhs = Counter(5)
+- expression 22 operands: lhs = Expression(51, Add), rhs = Counter(6)
+- expression 23 operands: lhs = Expression(52, Add), rhs = Expression(53, Add)
+- expression 24 operands: lhs = Counter(3), rhs = Zero
+- expression 25 operands: lhs = Counter(4), rhs = Counter(5)
+- expression 26 operands: lhs = Expression(47, Sub), rhs = Expression(48, Sub)
+- expression 27 operands: lhs = Zero, rhs = Zero
+- expression 28 operands: lhs = Expression(49, Sub), rhs = Counter(7)
+- expression 29 operands: lhs = Expression(50, Sub), rhs = Counter(5)
+- expression 30 operands: lhs = Expression(51, Add), rhs = Counter(6)
+- expression 31 operands: lhs = Expression(52, Add), rhs = Expression(53, Add)
+- expression 32 operands: lhs = Counter(3), rhs = Zero
+- expression 33 operands: lhs = Counter(4), rhs = Counter(5)
+- expression 34 operands: lhs = Expression(46, Add), rhs = Counter(4)
+- expression 35 operands: lhs = Expression(47, Sub), rhs = Expression(48, Sub)
+- expression 36 operands: lhs = Zero, rhs = Zero
+- expression 37 operands: lhs = Expression(49, Sub), rhs = Counter(7)
+- expression 38 operands: lhs = Expression(50, Sub), rhs = Counter(5)
+- expression 39 operands: lhs = Expression(51, Add), rhs = Counter(6)
+- expression 40 operands: lhs = Expression(52, Add), rhs = Expression(53, Add)
+- expression 41 operands: lhs = Counter(3), rhs = Zero
+- expression 42 operands: lhs = Counter(4), rhs = Counter(5)
+- expression 43 operands: lhs = Counter(9), rhs = Expression(44, Add)
+- expression 44 operands: lhs = Expression(45, Sub), rhs = Counter(6)
+- expression 45 operands: lhs = Expression(46, Add), rhs = Counter(4)
+- expression 46 operands: lhs = Expression(47, Sub), rhs = Expression(48, Sub)
+- expression 47 operands: lhs = Zero, rhs = Zero
+- expression 48 operands: lhs = Expression(49, Sub), rhs = Counter(7)
+- expression 49 operands: lhs = Expression(50, Sub), rhs = Counter(5)
+- expression 50 operands: lhs = Expression(51, Add), rhs = Counter(6)
+- expression 51 operands: lhs = Expression(52, Add), rhs = Expression(53, Add)
+- expression 52 operands: lhs = Counter(3), rhs = Zero
+- expression 53 operands: lhs = Counter(4), rhs = Counter(5)
+Number of file 0 mappings: 20
+- Code(Counter(0)) at (prev + 9, 5) to (start + 1, 16)
+- Code(Counter(1)) at (prev + 2, 16) to (start + 0, 21)
+- Code(Zero) at (prev + 1, 23) to (start + 0, 27)
+- Code(Zero) at (prev + 0, 28) to (start + 0, 30)
+- Code(Expression(0, Sub)) at (prev + 1, 14) to (start + 0, 15)
+    = (c1 - c2)
+- Code(Expression(1, Add)) at (prev + 1, 13) to (start + 0, 30)
+    = ((Zero - Zero) + (c1 - c2))
+- Code(Counter(9)) at (prev + 0, 30) to (start + 0, 31)
+- Code(Zero) at (prev + 1, 16) to (start + 1, 10)
+- Code(Expression(50, Sub)) at (prev + 3, 13) to (start + 0, 14)
+    = (((c3 + Zero) + (c4 + c5)) - c6)
+- Code(Expression(51, Add)) at (prev + 0, 18) to (start + 0, 23)
+    = ((c3 + Zero) + (c4 + c5))
+- Code(Expression(10, Add)) at (prev + 1, 16) to (start + 0, 20)
+    = ((((c3 + Zero) + (c4 + c5)) - c6) + Zero)
+- Code(Expression(49, Sub)) at (prev + 1, 20) to (start + 0, 25)
+    = ((((c3 + Zero) + (c4 + c5)) - c6) - c5)
+- Code(Zero) at (prev + 1, 27) to (start + 0, 31)
+- Code(Zero) at (prev + 0, 32) to (start + 0, 34)
+- Code(Expression(48, Sub)) at (prev + 1, 18) to (start + 0, 19)
+    = (((((c3 + Zero) + (c4 + c5)) - c6) - c5) - c7)
+- Code(Expression(46, Add)) at (prev + 1, 17) to (start + 0, 34)
+    = ((Zero - Zero) + (((((c3 + Zero) + (c4 + c5)) - c6) - c5) - c7))
+- Code(Expression(45, Sub)) at (prev + 0, 34) to (start + 0, 35)
+    = (((Zero - Zero) + (((((c3 + Zero) + (c4 + c5)) - c6) - c5) - c7)) - c4)
+- Code(Zero) at (prev + 1, 20) to (start + 1, 14)
+- Code(Counter(6)) at (prev + 3, 9) to (start + 0, 15)
+- Code(Expression(43, Add)) at (prev + 1, 5) to (start + 0, 6)
+    = (c9 + ((((Zero - Zero) + (((((c3 + Zero) + (c4 + c5)) - c6) - c5) - c7)) - c4) + c6))
+
+Function name: <loops_branches::DisplayTest as core::fmt::Display>::fmt
+Raw bytes (266): 0x[01, 01, 38, 01, 05, 02, 09, 0e, 12, 00, 00, 02, 09, d3, 01, 19, d7, 01, db, 01, 05, 0d, 11, 15, d7, 01, db, 01, 05, 0d, 11, 15, ce, 01, 00, d3, 01, 19, d7, 01, db, 01, 05, 0d, 11, 15, ce, 01, 11, d3, 01, 19, d7, 01, db, 01, 05, 0d, 11, 15, ca, 01, 1d, ce, 01, 11, d3, 01, 19, d7, 01, db, 01, 05, 0d, 11, 15, c2, 01, c6, 01, 00, 00, ca, 01, 1d, ce, 01, 11, d3, 01, 19, d7, 01, db, 01, 05, 0d, 11, 15, bf, 01, 15, c2, 01, c6, 01, 00, 00, ca, 01, 1d, ce, 01, 11, d3, 01, 19, d7, 01, db, 01, 05, 0d, 11, 15, ba, 01, df, 01, bf, 01, 15, c2, 01, c6, 01, 00, 00, ca, 01, 1d, ce, 01, 11, d3, 01, 19, d7, 01, db, 01, 05, 0d, 11, 15, 19, 25, 14, 01, 22, 05, 01, 11, 00, 01, 12, 01, 0a, 02, 02, 10, 00, 15, 00, 01, 17, 00, 1b, 00, 00, 1c, 00, 1e, 12, 01, 0e, 00, 0f, 0b, 01, 0d, 00, 1e, 25, 00, 1e, 00, 1f, ce, 01, 02, 0d, 00, 0e, d3, 01, 00, 12, 00, 17, 33, 01, 10, 00, 15, 00, 00, 16, 01, 0e, ca, 01, 02, 14, 00, 19, 00, 01, 1b, 00, 1f, 00, 00, 20, 00, 22, c6, 01, 01, 12, 00, 13, bf, 01, 01, 11, 00, 22, ba, 01, 00, 22, 00, 23, 19, 03, 09, 00, 0f, b7, 01, 01, 05, 00, 06]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 56
+- expression 0 operands: lhs = Counter(0), rhs = Counter(1)
+- expression 1 operands: lhs = Expression(0, Sub), rhs = Counter(2)
+- expression 2 operands: lhs = Expression(3, Sub), rhs = Expression(4, Sub)
+- expression 3 operands: lhs = Zero, rhs = Zero
+- expression 4 operands: lhs = Expression(0, Sub), rhs = Counter(2)
+- expression 5 operands: lhs = Expression(52, Add), rhs = Counter(6)
+- expression 6 operands: lhs = Expression(53, Add), rhs = Expression(54, Add)
+- expression 7 operands: lhs = Counter(1), rhs = Counter(3)
+- expression 8 operands: lhs = Counter(4), rhs = Counter(5)
+- expression 9 operands: lhs = Expression(53, Add), rhs = Expression(54, Add)
+- expression 10 operands: lhs = Counter(1), rhs = Counter(3)
+- expression 11 operands: lhs = Counter(4), rhs = Counter(5)
+- expression 12 operands: lhs = Expression(51, Sub), rhs = Zero
+- expression 13 operands: lhs = Expression(52, Add), rhs = Counter(6)
+- expression 14 operands: lhs = Expression(53, Add), rhs = Expression(54, Add)
+- expression 15 operands: lhs = Counter(1), rhs = Counter(3)
+- expression 16 operands: lhs = Counter(4), rhs = Counter(5)
+- expression 17 operands: lhs = Expression(51, Sub), rhs = Counter(4)
+- expression 18 operands: lhs = Expression(52, Add), rhs = Counter(6)
+- expression 19 operands: lhs = Expression(53, Add), rhs = Expression(54, Add)
+- expression 20 operands: lhs = Counter(1), rhs = Counter(3)
+- expression 21 operands: lhs = Counter(4), rhs = Counter(5)
+- expression 22 operands: lhs = Expression(50, Sub), rhs = Counter(7)
+- expression 23 operands: lhs = Expression(51, Sub), rhs = Counter(4)
+- expression 24 operands: lhs = Expression(52, Add), rhs = Counter(6)
+- expression 25 operands: lhs = Expression(53, Add), rhs = Expression(54, Add)
+- expression 26 operands: lhs = Counter(1), rhs = Counter(3)
+- expression 27 operands: lhs = Counter(4), rhs = Counter(5)
+- expression 28 operands: lhs = Expression(48, Sub), rhs = Expression(49, Sub)
+- expression 29 operands: lhs = Zero, rhs = Zero
+- expression 30 operands: lhs = Expression(50, Sub), rhs = Counter(7)
+- expression 31 operands: lhs = Expression(51, Sub), rhs = Counter(4)
+- expression 32 operands: lhs = Expression(52, Add), rhs = Counter(6)
+- expression 33 operands: lhs = Expression(53, Add), rhs = Expression(54, Add)
+- expression 34 operands: lhs = Counter(1), rhs = Counter(3)
+- expression 35 operands: lhs = Counter(4), rhs = Counter(5)
+- expression 36 operands: lhs = Expression(47, Add), rhs = Counter(5)
+- expression 37 operands: lhs = Expression(48, Sub), rhs = Expression(49, Sub)
+- expression 38 operands: lhs = Zero, rhs = Zero
+- expression 39 operands: lhs = Expression(50, Sub), rhs = Counter(7)
+- expression 40 operands: lhs = Expression(51, Sub), rhs = Counter(4)
+- expression 41 operands: lhs = Expression(52, Add), rhs = Counter(6)
+- expression 42 operands: lhs = Expression(53, Add), rhs = Expression(54, Add)
+- expression 43 operands: lhs = Counter(1), rhs = Counter(3)
+- expression 44 operands: lhs = Counter(4), rhs = Counter(5)
+- expression 45 operands: lhs = Expression(46, Sub), rhs = Expression(55, Add)
+- expression 46 operands: lhs = Expression(47, Add), rhs = Counter(5)
+- expression 47 operands: lhs = Expression(48, Sub), rhs = Expression(49, Sub)
+- expression 48 operands: lhs = Zero, rhs = Zero
+- expression 49 operands: lhs = Expression(50, Sub), rhs = Counter(7)
+- expression 50 operands: lhs = Expression(51, Sub), rhs = Counter(4)
+- expression 51 operands: lhs = Expression(52, Add), rhs = Counter(6)
+- expression 52 operands: lhs = Expression(53, Add), rhs = Expression(54, Add)
+- expression 53 operands: lhs = Counter(1), rhs = Counter(3)
+- expression 54 operands: lhs = Counter(4), rhs = Counter(5)
+- expression 55 operands: lhs = Counter(6), rhs = Counter(9)
+Number of file 0 mappings: 20
+- Code(Counter(0)) at (prev + 34, 5) to (start + 1, 17)
+- Code(Zero) at (prev + 1, 18) to (start + 1, 10)
+- Code(Expression(0, Sub)) at (prev + 2, 16) to (start + 0, 21)
+    = (c0 - c1)
+- Code(Zero) at (prev + 1, 23) to (start + 0, 27)
+- Code(Zero) at (prev + 0, 28) to (start + 0, 30)
+- Code(Expression(4, Sub)) at (prev + 1, 14) to (start + 0, 15)
+    = ((c0 - c1) - c2)
+- Code(Expression(2, Add)) at (prev + 1, 13) to (start + 0, 30)
+    = ((Zero - Zero) + ((c0 - c1) - c2))
+- Code(Counter(9)) at (prev + 0, 30) to (start + 0, 31)
+- Code(Expression(51, Sub)) at (prev + 2, 13) to (start + 0, 14)
+    = (((c1 + c3) + (c4 + c5)) - c6)
+- Code(Expression(52, Add)) at (prev + 0, 18) to (start + 0, 23)
+    = ((c1 + c3) + (c4 + c5))
+- Code(Expression(12, Add)) at (prev + 1, 16) to (start + 0, 21)
+    = ((((c1 + c3) + (c4 + c5)) - c6) + Zero)
+- Code(Zero) at (prev + 0, 22) to (start + 1, 14)
+- Code(Expression(50, Sub)) at (prev + 2, 20) to (start + 0, 25)
+    = ((((c1 + c3) + (c4 + c5)) - c6) - c4)
+- Code(Zero) at (prev + 1, 27) to (start + 0, 31)
+- Code(Zero) at (prev + 0, 32) to (start + 0, 34)
+- Code(Expression(49, Sub)) at (prev + 1, 18) to (start + 0, 19)
+    = (((((c1 + c3) + (c4 + c5)) - c6) - c4) - c7)
+- Code(Expression(47, Add)) at (prev + 1, 17) to (start + 0, 34)
+    = ((Zero - Zero) + (((((c1 + c3) + (c4 + c5)) - c6) - c4) - c7))
+- Code(Expression(46, Sub)) at (prev + 0, 34) to (start + 0, 35)
+    = (((Zero - Zero) + (((((c1 + c3) + (c4 + c5)) - c6) - c4) - c7)) - c5)
+- Code(Counter(6)) at (prev + 3, 9) to (start + 0, 15)
+- Code(Expression(45, Add)) at (prev + 1, 5) to (start + 0, 6)
+    = ((((Zero - Zero) + (((((c1 + c3) + (c4 + c5)) - c6) - c4) - c7)) - c5) + (c6 + c9))
+
+Function name: loops_branches::main
+Raw bytes (9): 0x[01, 01, 00, 01, 01, 37, 01, 05, 02]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 0
+Number of file 0 mappings: 1
+- Code(Counter(0)) at (prev + 55, 1) to (start + 5, 2)
+

tests/coverage-map/status-quo/loops_branches.rs

@@ -0,0 +1,60 @@
+#![allow(unused_assignments, unused_variables, while_true)]
+
+// This test confirms that (1) unexecuted infinite loops are handled correctly by the
+// InstrumentCoverage MIR pass; and (2) Counter Expressions that subtract from zero can be dropped.
+
+struct DebugTest;
+
+impl std::fmt::Debug for DebugTest {
+    fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
+        if true {
+            if false {
+                while true {}
+            }
+            write!(f, "cool")?;
+        } else {
+        }
+
+        for i in 0..10 {
+            if true {
+                if false {
+                    while true {}
+                }
+                write!(f, "cool")?;
+            } else {
+            }
+        }
+        Ok(())
+    }
+}
+
+struct DisplayTest;
+
+impl std::fmt::Display for DisplayTest {
+    fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
+        if false {
+        } else {
+            if false {
+                while true {}
+            }
+            write!(f, "cool")?;
+        }
+        for i in 0..10 {
+            if false {
+            } else {
+                if false {
+                    while true {}
+                }
+                write!(f, "cool")?;
+            }
+        }
+        Ok(())
+    }
+}
+
+fn main() {
+    let debug_test = DebugTest;
+    println!("{:?}", debug_test);
+    let display_test = DisplayTest;
+    println!("{}", display_test);
+}

tests/coverage-map/status-quo/match_or_pattern.cov-map

@@ -0,0 +1,83 @@
+Function name: match_or_pattern::main
+Raw bytes (202): 0x[01, 01, 23, 01, 05, 05, 02, 09, 0d, 2f, 11, 09, 0d, 2b, 15, 2f, 11, 09, 0d, 15, 26, 2b, 15, 2f, 11, 09, 0d, 19, 1d, 57, 21, 19, 1d, 53, 25, 57, 21, 19, 1d, 25, 4e, 53, 25, 57, 21, 19, 1d, 29, 2d, 7f, 31, 29, 2d, 7b, 35, 7f, 31, 29, 2d, 35, 76, 7b, 35, 7f, 31, 29, 2d, 39, 3d, 8b, 01, 41, 39, 3d, 19, 01, 01, 01, 08, 0f, 05, 08, 10, 03, 06, 02, 03, 06, 00, 07, 07, 01, 0b, 00, 11, 11, 03, 1b, 00, 1d, 2f, 01, 0e, 00, 10, 2b, 02, 08, 00, 0f, 15, 00, 10, 03, 06, 26, 03, 06, 00, 07, 23, 01, 0b, 00, 11, 21, 01, 1b, 00, 1d, 57, 01, 0e, 00, 10, 53, 02, 08, 00, 0f, 25, 00, 10, 03, 06, 4e, 03, 06, 00, 07, 4b, 01, 0b, 00, 11, 31, 01, 1b, 00, 1d, 7f, 01, 0e, 00, 10, 7b, 02, 08, 00, 0f, 35, 00, 10, 03, 06, 76, 03, 06, 00, 07, 73, 01, 0b, 00, 11, 41, 01, 1b, 00, 1d, 8b, 01, 01, 0e, 00, 10, 87, 01, 02, 01, 00, 02]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 35
+- expression 0 operands: lhs = Counter(0), rhs = Counter(1)
+- expression 1 operands: lhs = Counter(1), rhs = Expression(0, Sub)
+- expression 2 operands: lhs = Counter(2), rhs = Counter(3)
+- expression 3 operands: lhs = Expression(11, Add), rhs = Counter(4)
+- expression 4 operands: lhs = Counter(2), rhs = Counter(3)
+- expression 5 operands: lhs = Expression(10, Add), rhs = Counter(5)
+- expression 6 operands: lhs = Expression(11, Add), rhs = Counter(4)
+- expression 7 operands: lhs = Counter(2), rhs = Counter(3)
+- expression 8 operands: lhs = Counter(5), rhs = Expression(9, Sub)
+- expression 9 operands: lhs = Expression(10, Add), rhs = Counter(5)
+- expression 10 operands: lhs = Expression(11, Add), rhs = Counter(4)
+- expression 11 operands: lhs = Counter(2), rhs = Counter(3)
+- expression 12 operands: lhs = Counter(6), rhs = Counter(7)
+- expression 13 operands: lhs = Expression(21, Add), rhs = Counter(8)
+- expression 14 operands: lhs = Counter(6), rhs = Counter(7)
+- expression 15 operands: lhs = Expression(20, Add), rhs = Counter(9)
+- expression 16 operands: lhs = Expression(21, Add), rhs = Counter(8)
+- expression 17 operands: lhs = Counter(6), rhs = Counter(7)
+- expression 18 operands: lhs = Counter(9), rhs = Expression(19, Sub)
+- expression 19 operands: lhs = Expression(20, Add), rhs = Counter(9)
+- expression 20 operands: lhs = Expression(21, Add), rhs = Counter(8)
+- expression 21 operands: lhs = Counter(6), rhs = Counter(7)
+- expression 22 operands: lhs = Counter(10), rhs = Counter(11)
+- expression 23 operands: lhs = Expression(31, Add), rhs = Counter(12)
+- expression 24 operands: lhs = Counter(10), rhs = Counter(11)
+- expression 25 operands: lhs = Expression(30, Add), rhs = Counter(13)
+- expression 26 operands: lhs = Expression(31, Add), rhs = Counter(12)
+- expression 27 operands: lhs = Counter(10), rhs = Counter(11)
+- expression 28 operands: lhs = Counter(13), rhs = Expression(29, Sub)
+- expression 29 operands: lhs = Expression(30, Add), rhs = Counter(13)
+- expression 30 operands: lhs = Expression(31, Add), rhs = Counter(12)
+- expression 31 operands: lhs = Counter(10), rhs = Counter(11)
+- expression 32 operands: lhs = Counter(14), rhs = Counter(15)
+- expression 33 operands: lhs = Expression(34, Add), rhs = Counter(16)
+- expression 34 operands: lhs = Counter(14), rhs = Counter(15)
+Number of file 0 mappings: 25
+- Code(Counter(0)) at (prev + 1, 1) to (start + 8, 15)
+- Code(Counter(1)) at (prev + 8, 16) to (start + 3, 6)
+- Code(Expression(0, Sub)) at (prev + 3, 6) to (start + 0, 7)
+    = (c0 - c1)
+- Code(Expression(1, Add)) at (prev + 1, 11) to (start + 0, 17)
+    = (c1 + (c0 - c1))
+- Code(Counter(4)) at (prev + 3, 27) to (start + 0, 29)
+- Code(Expression(11, Add)) at (prev + 1, 14) to (start + 0, 16)
+    = (c2 + c3)
+- Code(Expression(10, Add)) at (prev + 2, 8) to (start + 0, 15)
+    = ((c2 + c3) + c4)
+- Code(Counter(5)) at (prev + 0, 16) to (start + 3, 6)
+- Code(Expression(9, Sub)) at (prev + 3, 6) to (start + 0, 7)
+    = (((c2 + c3) + c4) - c5)
+- Code(Expression(8, Add)) at (prev + 1, 11) to (start + 0, 17)
+    = (c5 + (((c2 + c3) + c4) - c5))
+- Code(Counter(8)) at (prev + 1, 27) to (start + 0, 29)
+- Code(Expression(21, Add)) at (prev + 1, 14) to (start + 0, 16)
+    = (c6 + c7)
+- Code(Expression(20, Add)) at (prev + 2, 8) to (start + 0, 15)
+    = ((c6 + c7) + c8)
+- Code(Counter(9)) at (prev + 0, 16) to (start + 3, 6)
+- Code(Expression(19, Sub)) at (prev + 3, 6) to (start + 0, 7)
+    = (((c6 + c7) + c8) - c9)
+- Code(Expression(18, Add)) at (prev + 1, 11) to (start + 0, 17)
+    = (c9 + (((c6 + c7) + c8) - c9))
+- Code(Counter(12)) at (prev + 1, 27) to (start + 0, 29)
+- Code(Expression(31, Add)) at (prev + 1, 14) to (start + 0, 16)
+    = (c10 + c11)
+- Code(Expression(30, Add)) at (prev + 2, 8) to (start + 0, 15)
+    = ((c10 + c11) + c12)
+- Code(Counter(13)) at (prev + 0, 16) to (start + 3, 6)
+- Code(Expression(29, Sub)) at (prev + 3, 6) to (start + 0, 7)
+    = (((c10 + c11) + c12) - c13)
+- Code(Expression(28, Add)) at (prev + 1, 11) to (start + 0, 17)
+    = (c13 + (((c10 + c11) + c12) - c13))
+- Code(Counter(16)) at (prev + 1, 27) to (start + 0, 29)
+- Code(Expression(34, Add)) at (prev + 1, 14) to (start + 0, 16)
+    = (c14 + c15)
+- Code(Expression(33, Add)) at (prev + 2, 1) to (start + 0, 2)
+    = ((c14 + c15) + c16)
+

tests/coverage-map/status-quo/match_or_pattern.rs

@@ -0,0 +1,43 @@
+fn main() {
+    // Initialize test constants in a way that cannot be determined at compile time, to ensure
+    // rustc and LLVM cannot optimize out statements (or coverage counters) downstream from
+    // dependent conditions.
+    let is_true = std::env::args().len() == 1;
+
+    let mut a: u8 = 0;
+    let mut b: u8 = 0;
+    if is_true {
+        a = 2;
+        b = 0;
+    }
+    match (a, b) {
+        // Or patterns generate MIR `SwitchInt` with multiple targets to the same `BasicBlock`.
+        // This test confirms a fix for Issue #79569.
+        (0 | 1, 2 | 3) => {}
+        _ => {}
+    }
+    if is_true {
+        a = 0;
+        b = 0;
+    }
+    match (a, b) {
+        (0 | 1, 2 | 3) => {}
+        _ => {}
+    }
+    if is_true {
+        a = 2;
+        b = 2;
+    }
+    match (a, b) {
+        (0 | 1, 2 | 3) => {}
+        _ => {}
+    }
+    if is_true {
+        a = 0;
+        b = 2;
+    }
+    match (a, b) {
+        (0 | 1, 2 | 3) => {}
+        _ => {}
+    }
+}

tests/coverage-map/status-quo/nested_loops.cov-map

@@ -0,0 +1,51 @@
+Function name: nested_loops::main
+Raw bytes (115): 0x[01, 01, 17, 01, 57, 05, 09, 03, 0d, 4e, 53, 03, 0d, 15, 19, 4b, 09, 4e, 53, 03, 0d, 15, 19, 46, 05, 4b, 09, 4e, 53, 03, 0d, 15, 19, 42, 19, 46, 05, 4b, 09, 4e, 53, 03, 0d, 15, 19, 05, 09, 11, 0d, 0d, 01, 01, 01, 02, 1b, 03, 04, 13, 00, 20, 4e, 01, 0d, 01, 18, 4b, 02, 12, 00, 17, 46, 01, 10, 00, 16, 05, 01, 11, 00, 16, 42, 01, 0e, 03, 16, 3e, 04, 11, 01, 1b, 11, 02, 15, 00, 21, 15, 01, 18, 02, 12, 19, 03, 0e, 00, 0f, 57, 02, 09, 00, 17, 5b, 02, 01, 00, 02]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 23
+- expression 0 operands: lhs = Counter(0), rhs = Expression(21, Add)
+- expression 1 operands: lhs = Counter(1), rhs = Counter(2)
+- expression 2 operands: lhs = Expression(0, Add), rhs = Counter(3)
+- expression 3 operands: lhs = Expression(19, Sub), rhs = Expression(20, Add)
+- expression 4 operands: lhs = Expression(0, Add), rhs = Counter(3)
+- expression 5 operands: lhs = Counter(5), rhs = Counter(6)
+- expression 6 operands: lhs = Expression(18, Add), rhs = Counter(2)
+- expression 7 operands: lhs = Expression(19, Sub), rhs = Expression(20, Add)
+- expression 8 operands: lhs = Expression(0, Add), rhs = Counter(3)
+- expression 9 operands: lhs = Counter(5), rhs = Counter(6)
+- expression 10 operands: lhs = Expression(17, Sub), rhs = Counter(1)
+- expression 11 operands: lhs = Expression(18, Add), rhs = Counter(2)
+- expression 12 operands: lhs = Expression(19, Sub), rhs = Expression(20, Add)
+- expression 13 operands: lhs = Expression(0, Add), rhs = Counter(3)
+- expression 14 operands: lhs = Counter(5), rhs = Counter(6)
+- expression 15 operands: lhs = Expression(16, Sub), rhs = Counter(6)
+- expression 16 operands: lhs = Expression(17, Sub), rhs = Counter(1)
+- expression 17 operands: lhs = Expression(18, Add), rhs = Counter(2)
+- expression 18 operands: lhs = Expression(19, Sub), rhs = Expression(20, Add)
+- expression 19 operands: lhs = Expression(0, Add), rhs = Counter(3)
+- expression 20 operands: lhs = Counter(5), rhs = Counter(6)
+- expression 21 operands: lhs = Counter(1), rhs = Counter(2)
+- expression 22 operands: lhs = Counter(4), rhs = Counter(3)
+Number of file 0 mappings: 13
+- Code(Counter(0)) at (prev + 1, 1) to (start + 2, 27)
+- Code(Expression(0, Add)) at (prev + 4, 19) to (start + 0, 32)
+    = (c0 + (c1 + c2))
+- Code(Expression(19, Sub)) at (prev + 1, 13) to (start + 1, 24)
+    = ((c0 + (c1 + c2)) - c3)
+- Code(Expression(18, Add)) at (prev + 2, 18) to (start + 0, 23)
+    = (((c0 + (c1 + c2)) - c3) + (c5 + c6))
+- Code(Expression(17, Sub)) at (prev + 1, 16) to (start + 0, 22)
+    = ((((c0 + (c1 + c2)) - c3) + (c5 + c6)) - c2)
+- Code(Counter(1)) at (prev + 1, 17) to (start + 0, 22)
+- Code(Expression(16, Sub)) at (prev + 1, 14) to (start + 3, 22)
+    = (((((c0 + (c1 + c2)) - c3) + (c5 + c6)) - c2) - c1)
+- Code(Expression(15, Sub)) at (prev + 4, 17) to (start + 1, 27)
+    = ((((((c0 + (c1 + c2)) - c3) + (c5 + c6)) - c2) - c1) - c6)
+- Code(Counter(4)) at (prev + 2, 21) to (start + 0, 33)
+- Code(Counter(5)) at (prev + 1, 24) to (start + 2, 18)
+- Code(Counter(6)) at (prev + 3, 14) to (start + 0, 15)
+- Code(Expression(21, Add)) at (prev + 2, 9) to (start + 0, 23)
+    = (c1 + c2)
+- Code(Expression(22, Add)) at (prev + 2, 1) to (start + 0, 2)
+    = (c4 + c3)
+

tests/coverage-map/status-quo/nested_loops.rs

@@ -0,0 +1,25 @@
+fn main() {
+    let is_true = std::env::args().len() == 1;
+    let mut countdown = 10;
+
+    'outer: while countdown > 0 {
+        let mut a = 100;
+        let mut b = 100;
+        for _ in 0..50 {
+            if a < 30 {
+                break;
+            }
+            a -= 5;
+            b -= 5;
+            if b < 90 {
+                a -= 10;
+                if is_true {
+                    break 'outer;
+                } else {
+                    a -= 2;
+                }
+            }
+        }
+        countdown -= 1;
+    }
+}

tests/coverage-map/status-quo/no_cov_crate.cov-map

@@ -0,0 +1,78 @@
+Function name: no_cov_crate::add_coverage_1
+Raw bytes (9): 0x[01, 01, 00, 01, 01, 14, 01, 02, 02]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 0
+Number of file 0 mappings: 1
+- Code(Counter(0)) at (prev + 20, 1) to (start + 2, 2)
+
+Function name: no_cov_crate::add_coverage_2
+Raw bytes (9): 0x[01, 01, 00, 01, 01, 18, 01, 02, 02]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 0
+Number of file 0 mappings: 1
+- Code(Counter(0)) at (prev + 24, 1) to (start + 2, 2)
+
+Function name: no_cov_crate::add_coverage_not_called (unused)
+Raw bytes (9): 0x[01, 01, 00, 01, 01, 1d, 01, 02, 02]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 0
+Number of file 0 mappings: 1
+- Code(Counter(0)) at (prev + 29, 1) to (start + 2, 2)
+
+Function name: no_cov_crate::main
+Raw bytes (9): 0x[01, 01, 00, 01, 01, 4d, 01, 0b, 02]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 0
+Number of file 0 mappings: 1
+- Code(Counter(0)) at (prev + 77, 1) to (start + 11, 2)
+
+Function name: no_cov_crate::nested_fns::outer
+Raw bytes (9): 0x[01, 01, 00, 01, 01, 31, 05, 0c, 06]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 0
+Number of file 0 mappings: 1
+- Code(Counter(0)) at (prev + 49, 5) to (start + 12, 6)
+
+Function name: no_cov_crate::nested_fns::outer_both_covered
+Raw bytes (9): 0x[01, 01, 00, 01, 01, 3f, 05, 0b, 06]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 0
+Number of file 0 mappings: 1
+- Code(Counter(0)) at (prev + 63, 5) to (start + 11, 6)
+
+Function name: no_cov_crate::nested_fns::outer_both_covered::inner
+Raw bytes (28): 0x[01, 01, 02, 01, 05, 05, 02, 04, 01, 43, 09, 01, 17, 05, 01, 18, 02, 0e, 02, 02, 14, 02, 0e, 07, 03, 09, 00, 0a]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 2
+- expression 0 operands: lhs = Counter(0), rhs = Counter(1)
+- expression 1 operands: lhs = Counter(1), rhs = Expression(0, Sub)
+Number of file 0 mappings: 4
+- Code(Counter(0)) at (prev + 67, 9) to (start + 1, 23)
+- Code(Counter(1)) at (prev + 1, 24) to (start + 2, 14)
+- Code(Expression(0, Sub)) at (prev + 2, 20) to (start + 2, 14)
+    = (c0 - c1)
+- Code(Expression(1, Add)) at (prev + 3, 9) to (start + 0, 10)
+    = (c1 + (c0 - c1))
+
+Function name: no_cov_crate::nested_fns::outer_not_covered::inner
+Raw bytes (28): 0x[01, 01, 02, 01, 05, 05, 02, 04, 01, 26, 09, 01, 17, 05, 01, 18, 02, 0e, 02, 02, 14, 02, 0e, 07, 03, 09, 00, 0a]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 2
+- expression 0 operands: lhs = Counter(0), rhs = Counter(1)
+- expression 1 operands: lhs = Counter(1), rhs = Expression(0, Sub)
+Number of file 0 mappings: 4
+- Code(Counter(0)) at (prev + 38, 9) to (start + 1, 23)
+- Code(Counter(1)) at (prev + 1, 24) to (start + 2, 14)
+- Code(Expression(0, Sub)) at (prev + 2, 20) to (start + 2, 14)
+    = (c0 - c1)
+- Code(Expression(1, Add)) at (prev + 3, 9) to (start + 0, 10)
+    = (c1 + (c0 - c1))
+

tests/coverage-map/status-quo/no_cov_crate.rs

@@ -0,0 +1,88 @@
+// Enables `no_coverage` on the entire crate
+#![feature(no_coverage)]
+
+#[no_coverage]
+fn do_not_add_coverage_1() {
+    println!("called but not covered");
+}
+
+fn do_not_add_coverage_2() {
+    #![no_coverage]
+    println!("called but not covered");
+}
+
+#[no_coverage]
+#[allow(dead_code)]
+fn do_not_add_coverage_not_called() {
+    println!("not called and not covered");
+}
+
+fn add_coverage_1() {
+    println!("called and covered");
+}
+
+fn add_coverage_2() {
+    println!("called and covered");
+}
+
+#[allow(dead_code)]
+fn add_coverage_not_called() {
+    println!("not called but covered");
+}
+
+// FIXME: These test-cases illustrate confusing results of nested functions.
+// See https://github.com/rust-lang/rust/issues/93319
+mod nested_fns {
+    #[no_coverage]
+    pub fn outer_not_covered(is_true: bool) {
+        fn inner(is_true: bool) {
+            if is_true {
+                println!("called and covered");
+            } else {
+                println!("absolutely not covered");
+            }
+        }
+        println!("called but not covered");
+        inner(is_true);
+    }
+
+    pub fn outer(is_true: bool) {
+        println!("called and covered");
+        inner_not_covered(is_true);
+
+        #[no_coverage]
+        fn inner_not_covered(is_true: bool) {
+            if is_true {
+                println!("called but not covered");
+            } else {
+                println!("absolutely not covered");
+            }
+        }
+    }
+
+    pub fn outer_both_covered(is_true: bool) {
+        println!("called and covered");
+        inner(is_true);
+
+        fn inner(is_true: bool) {
+            if is_true {
+                println!("called and covered");
+            } else {
+                println!("absolutely not covered");
+            }
+        }
+    }
+}
+
+fn main() {
+    let is_true = std::env::args().len() == 1;
+
+    do_not_add_coverage_1();
+    do_not_add_coverage_2();
+    add_coverage_1();
+    add_coverage_2();
+
+    nested_fns::outer_not_covered(is_true);
+    nested_fns::outer(is_true);
+    nested_fns::outer_both_covered(is_true);
+}

tests/coverage-map/status-quo/overflow.cov-map

@@ -0,0 +1,43 @@
+Function name: overflow::main
+Raw bytes (65): 0x[01, 01, 08, 01, 1b, 05, 1f, 09, 0d, 03, 11, 16, 05, 03, 11, 05, 1f, 09, 0d, 09, 01, 0f, 01, 01, 1b, 03, 02, 0b, 00, 18, 16, 01, 0c, 00, 1a, 05, 00, 1b, 03, 0a, 12, 03, 13, 00, 20, 09, 00, 21, 03, 0a, 0d, 03, 0a, 00, 0b, 1b, 01, 09, 00, 17, 11, 02, 05, 01, 02]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 8
+- expression 0 operands: lhs = Counter(0), rhs = Expression(6, Add)
+- expression 1 operands: lhs = Counter(1), rhs = Expression(7, Add)
+- expression 2 operands: lhs = Counter(2), rhs = Counter(3)
+- expression 3 operands: lhs = Expression(0, Add), rhs = Counter(4)
+- expression 4 operands: lhs = Expression(5, Sub), rhs = Counter(1)
+- expression 5 operands: lhs = Expression(0, Add), rhs = Counter(4)
+- expression 6 operands: lhs = Counter(1), rhs = Expression(7, Add)
+- expression 7 operands: lhs = Counter(2), rhs = Counter(3)
+Number of file 0 mappings: 9
+- Code(Counter(0)) at (prev + 15, 1) to (start + 1, 27)
+- Code(Expression(0, Add)) at (prev + 2, 11) to (start + 0, 24)
+    = (c0 + (c1 + (c2 + c3)))
+- Code(Expression(5, Sub)) at (prev + 1, 12) to (start + 0, 26)
+    = ((c0 + (c1 + (c2 + c3))) - c4)
+- Code(Counter(1)) at (prev + 0, 27) to (start + 3, 10)
+- Code(Expression(4, Sub)) at (prev + 3, 19) to (start + 0, 32)
+    = (((c0 + (c1 + (c2 + c3))) - c4) - c1)
+- Code(Counter(2)) at (prev + 0, 33) to (start + 3, 10)
+- Code(Counter(3)) at (prev + 3, 10) to (start + 0, 11)
+- Code(Expression(6, Add)) at (prev + 1, 9) to (start + 0, 23)
+    = (c1 + (c2 + c3))
+- Code(Counter(4)) at (prev + 2, 5) to (start + 1, 2)
+
+Function name: overflow::might_overflow
+Raw bytes (28): 0x[01, 01, 02, 01, 05, 05, 02, 04, 01, 04, 01, 01, 12, 05, 01, 13, 02, 06, 02, 02, 06, 00, 07, 07, 01, 09, 05, 02]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 2
+- expression 0 operands: lhs = Counter(0), rhs = Counter(1)
+- expression 1 operands: lhs = Counter(1), rhs = Expression(0, Sub)
+Number of file 0 mappings: 4
+- Code(Counter(0)) at (prev + 4, 1) to (start + 1, 18)
+- Code(Counter(1)) at (prev + 1, 19) to (start + 2, 6)
+- Code(Expression(0, Sub)) at (prev + 2, 6) to (start + 0, 7)
+    = (c0 - c1)
+- Code(Expression(1, Add)) at (prev + 1, 9) to (start + 5, 2)
+    = (c1 + (c0 - c1))
+

tests/coverage-map/status-quo/overflow.rs

@@ -0,0 +1,63 @@
+#![allow(unused_assignments)]
+// failure-status: 101
+
+fn might_overflow(to_add: u32) -> u32 {
+    if to_add > 5 {
+        println!("this will probably overflow");
+    }
+    let add_to = u32::MAX - 5;
+    println!("does {} + {} overflow?", add_to, to_add);
+    let result = to_add + add_to;
+    println!("continuing after overflow check");
+    result
+}
+
+fn main() -> Result<(), u8> {
+    let mut countdown = 10;
+    while countdown > 0 {
+        if countdown == 1 {
+            let result = might_overflow(10);
+            println!("Result: {}", result);
+        } else if countdown < 5 {
+            let result = might_overflow(1);
+            println!("Result: {}", result);
+        }
+        countdown -= 1;
+    }
+    Ok(())
+}
+
+// Notes:
+//   1. Compare this program and its coverage results to those of the very similar test `assert.rs`,
+//      and similar tests `panic_unwind.rs`, abort.rs` and `try_error_result.rs`.
+//   2. This test confirms the coverage generated when a program passes or fails a
+//      compiler-generated `TerminatorKind::Assert` (based on an overflow check, in this case).
+//   3. Similar to how the coverage instrumentation handles `TerminatorKind::Call`,
+//      compiler-generated assertion failures are assumed to be a symptom of a program bug, not
+//      expected behavior. To simplify the coverage graphs and keep instrumented programs as
+//      small and fast as possible, `Assert` terminators are assumed to always succeed, and
+//      therefore are considered "non-branching" terminators. So, an `Assert` terminator does not
+//      get its own coverage counter.
+//   4. After an unhandled panic or failed Assert, coverage results may not always be intuitive.
+//      In this test, the final count for the statements after the `if` block in `might_overflow()`
+//      is 4, even though the lines after `to_add + add_to` were executed only 3 times. Depending
+//      on the MIR graph and the structure of the code, this count could have been 3 (which might
+//      have been valid for the overflowed add `+`, but should have been 4 for the lines before
+//      the overflow. The reason for this potential uncertainty is, a `CounterKind` is incremented
+//      via StatementKind::Counter at the end of the block, but (as in the case in this test),
+//      a CounterKind::Expression is always evaluated. In this case, the expression was based on
+//      a `Counter` incremented as part of the evaluation of the `if` expression, which was
+//      executed, and counted, 4 times, before reaching the overflow add.
+
+// If the program did not overflow, the coverage for `might_overflow()` would look like this:
+//
+//     4|       |fn might_overflow(to_add: u32) -> u32 {
+//     5|      4|    if to_add > 5 {
+//     6|      0|        println!("this will probably overflow");
+//     7|      4|    }
+//     8|      4|    let add_to = u32::MAX - 5;
+//     9|      4|    println!("does {} + {} overflow?", add_to, to_add);
+//    10|      4|    let result = to_add + add_to;
+//    11|      4|    println!("continuing after overflow check");
+//    12|      4|    result
+//    13|      4|}

tests/coverage-map/status-quo/panic_unwind.cov-map

@@ -0,0 +1,40 @@
+Function name: panic_unwind::main
+Raw bytes (65): 0x[01, 01, 08, 01, 1b, 05, 1f, 09, 0d, 03, 11, 16, 05, 03, 11, 05, 1f, 09, 0d, 09, 01, 0d, 01, 01, 1b, 03, 02, 0b, 00, 18, 16, 01, 0c, 00, 1a, 05, 00, 1b, 02, 0a, 12, 02, 13, 00, 20, 09, 00, 21, 02, 0a, 0d, 02, 0a, 00, 0b, 1b, 01, 09, 00, 17, 11, 02, 05, 01, 02]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 8
+- expression 0 operands: lhs = Counter(0), rhs = Expression(6, Add)
+- expression 1 operands: lhs = Counter(1), rhs = Expression(7, Add)
+- expression 2 operands: lhs = Counter(2), rhs = Counter(3)
+- expression 3 operands: lhs = Expression(0, Add), rhs = Counter(4)
+- expression 4 operands: lhs = Expression(5, Sub), rhs = Counter(1)
+- expression 5 operands: lhs = Expression(0, Add), rhs = Counter(4)
+- expression 6 operands: lhs = Counter(1), rhs = Expression(7, Add)
+- expression 7 operands: lhs = Counter(2), rhs = Counter(3)
+Number of file 0 mappings: 9
+- Code(Counter(0)) at (prev + 13, 1) to (start + 1, 27)
+- Code(Expression(0, Add)) at (prev + 2, 11) to (start + 0, 24)
+    = (c0 + (c1 + (c2 + c3)))
+- Code(Expression(5, Sub)) at (prev + 1, 12) to (start + 0, 26)
+    = ((c0 + (c1 + (c2 + c3))) - c4)
+- Code(Counter(1)) at (prev + 0, 27) to (start + 2, 10)
+- Code(Expression(4, Sub)) at (prev + 2, 19) to (start + 0, 32)
+    = (((c0 + (c1 + (c2 + c3))) - c4) - c1)
+- Code(Counter(2)) at (prev + 0, 33) to (start + 2, 10)
+- Code(Counter(3)) at (prev + 2, 10) to (start + 0, 11)
+- Code(Expression(6, Add)) at (prev + 1, 9) to (start + 0, 23)
+    = (c1 + (c2 + c3))
+- Code(Counter(4)) at (prev + 2, 5) to (start + 1, 2)
+
+Function name: panic_unwind::might_panic
+Raw bytes (21): 0x[01, 01, 01, 01, 05, 03, 01, 04, 01, 01, 14, 05, 02, 09, 01, 19, 02, 02, 0c, 03, 02]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 1
+- expression 0 operands: lhs = Counter(0), rhs = Counter(1)
+Number of file 0 mappings: 3
+- Code(Counter(0)) at (prev + 4, 1) to (start + 1, 20)
+- Code(Counter(1)) at (prev + 2, 9) to (start + 1, 25)
+- Code(Expression(0, Sub)) at (prev + 2, 12) to (start + 3, 2)
+    = (c0 - c1)
+

tests/coverage-map/status-quo/panic_unwind.rs

@@ -0,0 +1,31 @@
+#![allow(unused_assignments)]
+// failure-status: 101
+
+fn might_panic(should_panic: bool) {
+    if should_panic {
+        println!("panicking...");
+        panic!("panics");
+    } else {
+        println!("Don't Panic");
+    }
+}
+
+fn main() -> Result<(), u8> {
+    let mut countdown = 10;
+    while countdown > 0 {
+        if countdown == 1 {
+            might_panic(true);
+        } else if countdown < 5 {
+            might_panic(false);
+        }
+        countdown -= 1;
+    }
+    Ok(())
+}
+
+// Notes:
+//   1. Compare this program and its coverage results to those of the similar tests `abort.rs` and
+//      `try_error_result.rs`.
+//   2. Since the `panic_unwind.rs` test is allowed to unwind, it is also allowed to execute the
+//      normal program exit cleanup, including writing out the current values of the coverage
+//      counters.

tests/coverage-map/status-quo/partial_eq.cov-map

@@ -0,0 +1,64 @@
+Function name: <partial_eq::Version as core::clone::Clone>::clone (unused)
+Raw bytes (9): 0x[01, 01, 00, 01, 01, 04, 0a, 00, 0f]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 0
+Number of file 0 mappings: 1
+- Code(Counter(0)) at (prev + 4, 10) to (start + 0, 15)
+
+Function name: <partial_eq::Version as core::cmp::Ord>::cmp (unused)
+Raw bytes (14): 0x[01, 01, 00, 02, 01, 04, 33, 00, 34, 00, 00, 35, 00, 36]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 0
+Number of file 0 mappings: 2
+- Code(Counter(0)) at (prev + 4, 51) to (start + 0, 52)
+- Code(Zero) at (prev + 0, 53) to (start + 0, 54)
+
+Function name: <partial_eq::Version as core::cmp::PartialEq>::eq (unused)
+Raw bytes (14): 0x[01, 01, 00, 02, 01, 04, 18, 00, 19, 00, 00, 20, 00, 21]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 0
+Number of file 0 mappings: 2
+- Code(Counter(0)) at (prev + 4, 24) to (start + 0, 25)
+- Code(Zero) at (prev + 0, 32) to (start + 0, 33)
+
+Function name: <partial_eq::Version as core::cmp::PartialOrd>::partial_cmp
+Raw bytes (22): 0x[01, 01, 04, 07, 0b, 05, 09, 0f, 15, 0d, 11, 02, 01, 04, 27, 00, 28, 03, 00, 30, 00, 31]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 4
+- expression 0 operands: lhs = Expression(1, Add), rhs = Expression(2, Add)
+- expression 1 operands: lhs = Counter(1), rhs = Counter(2)
+- expression 2 operands: lhs = Expression(3, Add), rhs = Counter(5)
+- expression 3 operands: lhs = Counter(3), rhs = Counter(4)
+Number of file 0 mappings: 2
+- Code(Counter(0)) at (prev + 4, 39) to (start + 0, 40)
+- Code(Expression(0, Add)) at (prev + 0, 48) to (start + 0, 49)
+    = ((c1 + c2) + ((c3 + c4) + c5))
+
+Function name: <partial_eq::Version as core::fmt::Debug>::fmt
+Raw bytes (9): 0x[01, 01, 00, 01, 01, 04, 11, 00, 16]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 0
+Number of file 0 mappings: 1
+- Code(Counter(0)) at (prev + 4, 17) to (start + 0, 22)
+
+Function name: <partial_eq::Version>::new
+Raw bytes (9): 0x[01, 01, 00, 01, 01, 0c, 05, 06, 06]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 0
+Number of file 0 mappings: 1
+- Code(Counter(0)) at (prev + 12, 5) to (start + 6, 6)
+
+Function name: partial_eq::main
+Raw bytes (9): 0x[01, 01, 00, 01, 01, 15, 01, 05, 02]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 0
+Number of file 0 mappings: 1
+- Code(Counter(0)) at (prev + 21, 1) to (start + 5, 2)
+

tests/coverage-map/status-quo/partial_eq.rs

@@ -0,0 +1,46 @@
+// This test confirms an earlier problem was resolved, supporting the MIR graph generated by the
+// structure of this test.
+
+#[derive(Clone, Debug, PartialEq, Eq, PartialOrd, Ord)]
+pub struct Version {
+    major: usize,
+    minor: usize,
+    patch: usize,
+}
+
+impl Version {
+    pub fn new(major: usize, minor: usize, patch: usize) -> Self {
+        Self {
+            major,
+            minor,
+            patch,
+        }
+    }
+}
+
+fn main() {
+    let version_3_2_1 = Version::new(3, 2, 1);
+    let version_3_3_0 = Version::new(3, 3, 0);
+
+    println!("{:?} < {:?} = {}", version_3_2_1, version_3_3_0, version_3_2_1 < version_3_3_0);
+}
+
+/*
+
+This test verifies a bug was fixed that otherwise generated this error:
+
+thread 'rustc' panicked at 'No counters provided the source_hash for function:
+    Instance {
+        def: Item(WithOptConstParam {
+            did: DefId(0:101 ~ autocfg[c44a]::version::{impl#2}::partial_cmp),
+            const_param_did: None
+        }),
+        args: []
+    }'
+The `PartialOrd` derived by `Version` happened to generate a MIR that generated coverage
+without a code region associated with any `Counter`. Code regions were associated with at least
+one expression, which is allowed, but the `function_source_hash` was only passed to the codegen
+(coverage mapgen) phase from a `Counter`s code region. A new method was added to pass the
+`function_source_hash` without a code region, if necessary.
+
+*/

tests/coverage-map/status-quo/simple_loop.cov-map

@@ -0,0 +1,28 @@
+Function name: simple_loop::main
+Raw bytes (59): 0x[01, 01, 0a, 01, 05, 27, 09, 05, 02, 23, 09, 27, 09, 05, 02, 1e, 00, 23, 09, 27, 09, 05, 02, 07, 01, 03, 01, 09, 10, 05, 0a, 05, 05, 06, 02, 05, 06, 00, 07, 23, 05, 0d, 02, 0e, 1e, 04, 0d, 00, 12, 09, 02, 0a, 03, 0a, 1b, 06, 01, 00, 02]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 10
+- expression 0 operands: lhs = Counter(0), rhs = Counter(1)
+- expression 1 operands: lhs = Expression(9, Add), rhs = Counter(2)
+- expression 2 operands: lhs = Counter(1), rhs = Expression(0, Sub)
+- expression 3 operands: lhs = Expression(8, Add), rhs = Counter(2)
+- expression 4 operands: lhs = Expression(9, Add), rhs = Counter(2)
+- expression 5 operands: lhs = Counter(1), rhs = Expression(0, Sub)
+- expression 6 operands: lhs = Expression(7, Sub), rhs = Zero
+- expression 7 operands: lhs = Expression(8, Add), rhs = Counter(2)
+- expression 8 operands: lhs = Expression(9, Add), rhs = Counter(2)
+- expression 9 operands: lhs = Counter(1), rhs = Expression(0, Sub)
+Number of file 0 mappings: 7
+- Code(Counter(0)) at (prev + 3, 1) to (start + 9, 16)
+- Code(Counter(1)) at (prev + 10, 5) to (start + 5, 6)
+- Code(Expression(0, Sub)) at (prev + 5, 6) to (start + 0, 7)
+    = (c0 - c1)
+- Code(Expression(8, Add)) at (prev + 5, 13) to (start + 2, 14)
+    = ((c1 + (c0 - c1)) + c2)
+- Code(Expression(7, Sub)) at (prev + 4, 13) to (start + 0, 18)
+    = (((c1 + (c0 - c1)) + c2) - c2)
+- Code(Counter(2)) at (prev + 2, 10) to (start + 3, 10)
+- Code(Expression(6, Add)) at (prev + 6, 1) to (start + 0, 2)
+    = ((((c1 + (c0 - c1)) + c2) - c2) + Zero)
+

tests/coverage-map/status-quo/simple_loop.rs

@@ -0,0 +1,35 @@
+#![allow(unused_assignments)]
+
+fn main() {
+    // Initialize test constants in a way that cannot be determined at compile time, to ensure
+    // rustc and LLVM cannot optimize out statements (or coverage counters) downstream from
+    // dependent conditions.
+    let is_true = std::env::args().len() == 1;
+
+    let mut countdown = 0;
+
+    if
+        is_true
+    {
+        countdown
+        =
+            10
+        ;
+    }
+
+    loop
+    {
+        if
+            countdown
+                ==
+            0
+        {
+            break
+            ;
+        }
+        countdown
+        -=
+        1
+        ;
+    }
+}

tests/coverage-map/status-quo/simple_match.cov-map

@@ -0,0 +1,36 @@
+Function name: simple_match::main
+Raw bytes (82): 0x[01, 01, 0e, 01, 05, 2f, 33, 05, 02, 09, 0d, 2b, 11, 2f, 33, 05, 02, 09, 0d, 26, 00, 2b, 11, 2f, 33, 05, 02, 09, 0d, 09, 00, 0a, 01, 03, 01, 07, 0f, 05, 07, 10, 02, 06, 02, 02, 06, 00, 07, 2b, 05, 09, 00, 0d, 26, 05, 0d, 00, 16, 09, 02, 0d, 00, 0e, 23, 02, 11, 02, 12, 37, 04, 0d, 07, 0e, 0d, 0a, 0d, 00, 0f, 11, 03, 01, 00, 02]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 14
+- expression 0 operands: lhs = Counter(0), rhs = Counter(1)
+- expression 1 operands: lhs = Expression(11, Add), rhs = Expression(12, Add)
+- expression 2 operands: lhs = Counter(1), rhs = Expression(0, Sub)
+- expression 3 operands: lhs = Counter(2), rhs = Counter(3)
+- expression 4 operands: lhs = Expression(10, Add), rhs = Counter(4)
+- expression 5 operands: lhs = Expression(11, Add), rhs = Expression(12, Add)
+- expression 6 operands: lhs = Counter(1), rhs = Expression(0, Sub)
+- expression 7 operands: lhs = Counter(2), rhs = Counter(3)
+- expression 8 operands: lhs = Expression(9, Sub), rhs = Zero
+- expression 9 operands: lhs = Expression(10, Add), rhs = Counter(4)
+- expression 10 operands: lhs = Expression(11, Add), rhs = Expression(12, Add)
+- expression 11 operands: lhs = Counter(1), rhs = Expression(0, Sub)
+- expression 12 operands: lhs = Counter(2), rhs = Counter(3)
+- expression 13 operands: lhs = Counter(2), rhs = Zero
+Number of file 0 mappings: 10
+- Code(Counter(0)) at (prev + 3, 1) to (start + 7, 15)
+- Code(Counter(1)) at (prev + 7, 16) to (start + 2, 6)
+- Code(Expression(0, Sub)) at (prev + 2, 6) to (start + 0, 7)
+    = (c0 - c1)
+- Code(Expression(10, Add)) at (prev + 5, 9) to (start + 0, 13)
+    = ((c1 + (c0 - c1)) + (c2 + c3))
+- Code(Expression(9, Sub)) at (prev + 5, 13) to (start + 0, 22)
+    = (((c1 + (c0 - c1)) + (c2 + c3)) - c4)
+- Code(Counter(2)) at (prev + 2, 13) to (start + 0, 14)
+- Code(Expression(8, Add)) at (prev + 2, 17) to (start + 2, 18)
+    = ((((c1 + (c0 - c1)) + (c2 + c3)) - c4) + Zero)
+- Code(Expression(13, Add)) at (prev + 4, 13) to (start + 7, 14)
+    = (c2 + Zero)
+- Code(Counter(3)) at (prev + 10, 13) to (start + 0, 15)
+- Code(Counter(4)) at (prev + 3, 1) to (start + 0, 2)
+

tests/coverage-map/status-quo/simple_match.rs

@@ -0,0 +1,43 @@
+#![allow(unused_assignments, unused_variables)]
+
+fn main() {
+    // Initialize test constants in a way that cannot be determined at compile time, to ensure
+    // rustc and LLVM cannot optimize out statements (or coverage counters) downstream from
+    // dependent conditions.
+    let is_true = std::env::args().len() == 1;
+
+    let mut countdown = 1;
+    if is_true {
+        countdown = 0;
+    }
+
+    for
+        _
+    in
+        0..2
+    {
+        let z
+        ;
+        match
+            countdown
+        {
+            x
+            if
+                x
+                    <
+                1
+            =>
+            {
+                z = countdown
+                ;
+                let y = countdown
+                ;
+                countdown = 10
+                ;
+            }
+            _
+            =>
+            {}
+        }
+    }
+}

tests/coverage-map/status-quo/sort_groups.cov-map

@@ -0,0 +1,68 @@
+Function name: sort_groups::generic_fn::<&str>
+Raw bytes (28): 0x[01, 01, 02, 01, 05, 05, 02, 04, 01, 11, 01, 01, 0c, 05, 01, 0d, 02, 06, 02, 02, 06, 00, 07, 07, 01, 01, 00, 02]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 2
+- expression 0 operands: lhs = Counter(0), rhs = Counter(1)
+- expression 1 operands: lhs = Counter(1), rhs = Expression(0, Sub)
+Number of file 0 mappings: 4
+- Code(Counter(0)) at (prev + 17, 1) to (start + 1, 12)
+- Code(Counter(1)) at (prev + 1, 13) to (start + 2, 6)
+- Code(Expression(0, Sub)) at (prev + 2, 6) to (start + 0, 7)
+    = (c0 - c1)
+- Code(Expression(1, Add)) at (prev + 1, 1) to (start + 0, 2)
+    = (c1 + (c0 - c1))
+
+Function name: sort_groups::generic_fn::<()>
+Raw bytes (28): 0x[01, 01, 02, 01, 05, 05, 02, 04, 01, 11, 01, 01, 0c, 05, 01, 0d, 02, 06, 02, 02, 06, 00, 07, 07, 01, 01, 00, 02]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 2
+- expression 0 operands: lhs = Counter(0), rhs = Counter(1)
+- expression 1 operands: lhs = Counter(1), rhs = Expression(0, Sub)
+Number of file 0 mappings: 4
+- Code(Counter(0)) at (prev + 17, 1) to (start + 1, 12)
+- Code(Counter(1)) at (prev + 1, 13) to (start + 2, 6)
+- Code(Expression(0, Sub)) at (prev + 2, 6) to (start + 0, 7)
+    = (c0 - c1)
+- Code(Expression(1, Add)) at (prev + 1, 1) to (start + 0, 2)
+    = (c1 + (c0 - c1))
+
+Function name: sort_groups::generic_fn::<i32>
+Raw bytes (28): 0x[01, 01, 02, 01, 05, 05, 02, 04, 01, 11, 01, 01, 0c, 05, 01, 0d, 02, 06, 02, 02, 06, 00, 07, 07, 01, 01, 00, 02]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 2
+- expression 0 operands: lhs = Counter(0), rhs = Counter(1)
+- expression 1 operands: lhs = Counter(1), rhs = Expression(0, Sub)
+Number of file 0 mappings: 4
+- Code(Counter(0)) at (prev + 17, 1) to (start + 1, 12)
+- Code(Counter(1)) at (prev + 1, 13) to (start + 2, 6)
+- Code(Expression(0, Sub)) at (prev + 2, 6) to (start + 0, 7)
+    = (c0 - c1)
+- Code(Expression(1, Add)) at (prev + 1, 1) to (start + 0, 2)
+    = (c1 + (c0 - c1))
+
+Function name: sort_groups::main
+Raw bytes (28): 0x[01, 01, 02, 01, 05, 05, 02, 04, 01, 06, 01, 04, 0d, 00, 04, 0e, 02, 06, 02, 02, 06, 00, 07, 07, 01, 05, 02, 02]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 2
+- expression 0 operands: lhs = Counter(0), rhs = Counter(1)
+- expression 1 operands: lhs = Counter(1), rhs = Expression(0, Sub)
+Number of file 0 mappings: 4
+- Code(Counter(0)) at (prev + 6, 1) to (start + 4, 13)
+- Code(Zero) at (prev + 4, 14) to (start + 2, 6)
+- Code(Expression(0, Sub)) at (prev + 2, 6) to (start + 0, 7)
+    = (c0 - c1)
+- Code(Expression(1, Add)) at (prev + 1, 5) to (start + 2, 2)
+    = (c1 + (c0 - c1))
+
+Function name: sort_groups::other_fn
+Raw bytes (9): 0x[01, 01, 00, 01, 01, 17, 01, 00, 11]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 0
+Number of file 0 mappings: 1
+- Code(Counter(0)) at (prev + 23, 1) to (start + 0, 17)
+

tests/coverage-map/status-quo/sort_groups.rs

@@ -0,0 +1,23 @@
+// compile-flags: --edition=2021
+
+// Demonstrate that `sort_subviews.py` can sort instantiation groups into a
+// predictable order, while preserving their heterogeneous contents.
+
+fn main() {
+    let cond = std::env::args().len() > 1;
+    generic_fn::<()>(cond);
+    generic_fn::<&'static str>(!cond);
+    if false {
+        generic_fn::<char>(cond);
+    }
+    generic_fn::<i32>(cond);
+    other_fn();
+}
+
+fn generic_fn<T>(cond: bool) {
+    if cond {
+        println!("{}", std::any::type_name::<T>());
+    }
+}
+
+fn other_fn() {}

tests/coverage-map/status-quo/test_harness.cov-map

@@ -0,0 +1,24 @@
+Function name: test_harness::my_test
+Raw bytes (9): 0x[01, 01, 00, 01, 01, 0a, 01, 00, 10]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 0
+Number of file 0 mappings: 1
+- Code(Counter(0)) at (prev + 10, 1) to (start + 0, 16)
+
+Function name: test_harness::my_test::{closure#0}
+Raw bytes (9): 0x[01, 01, 00, 01, 01, 09, 01, 00, 08]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 0
+Number of file 0 mappings: 1
+- Code(Counter(0)) at (prev + 9, 1) to (start + 0, 8)
+
+Function name: test_harness::unused (unused)
+Raw bytes (9): 0x[01, 01, 00, 01, 01, 07, 01, 00, 0f]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 0
+Number of file 0 mappings: 1
+- Code(Counter(0)) at (prev + 7, 1) to (start + 0, 15)
+

tests/coverage-map/status-quo/test_harness.rs

@@ -0,0 +1,10 @@
+// Verify that the entry point injected by the test harness doesn't cause
+// weird artifacts in the coverage report (e.g. issue #10749).
+
+// compile-flags: --test
+
+#[allow(dead_code)]
+fn unused() {}
+
+#[test]
+fn my_test() {}

tests/coverage-map/status-quo/tight_inf_loop.cov-map

@@ -0,0 +1,12 @@
+Function name: tight_inf_loop::main
+Raw bytes (21): 0x[01, 01, 01, 01, 05, 03, 01, 01, 01, 01, 0d, 00, 02, 09, 00, 10, 02, 01, 06, 01, 02]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 1
+- expression 0 operands: lhs = Counter(0), rhs = Counter(1)
+Number of file 0 mappings: 3
+- Code(Counter(0)) at (prev + 1, 1) to (start + 1, 13)
+- Code(Zero) at (prev + 2, 9) to (start + 0, 16)
+- Code(Expression(0, Sub)) at (prev + 1, 6) to (start + 1, 2)
+    = (c0 - c1)
+

tests/coverage-map/status-quo/tight_inf_loop.rs

@@ -0,0 +1,5 @@
+fn main() {
+    if false {
+        loop {}
+    }
+}

tests/coverage-map/status-quo/try_error_result.cov-map

@@ -0,0 +1,226 @@
+Function name: <try_error_result::Thing1>::get_thing_2
+Raw bytes (28): 0x[01, 01, 02, 01, 05, 05, 02, 04, 01, 28, 05, 01, 18, 05, 02, 0d, 00, 14, 02, 02, 0d, 00, 1a, 07, 02, 05, 00, 06]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 2
+- expression 0 operands: lhs = Counter(0), rhs = Counter(1)
+- expression 1 operands: lhs = Counter(1), rhs = Expression(0, Sub)
+Number of file 0 mappings: 4
+- Code(Counter(0)) at (prev + 40, 5) to (start + 1, 24)
+- Code(Counter(1)) at (prev + 2, 13) to (start + 0, 20)
+- Code(Expression(0, Sub)) at (prev + 2, 13) to (start + 0, 26)
+    = (c0 - c1)
+- Code(Expression(1, Add)) at (prev + 2, 5) to (start + 0, 6)
+    = (c1 + (c0 - c1))
+
+Function name: <try_error_result::Thing2>::call
+Raw bytes (28): 0x[01, 01, 02, 01, 05, 05, 02, 04, 01, 33, 05, 01, 18, 05, 02, 0d, 00, 14, 02, 02, 0d, 00, 13, 07, 02, 05, 00, 06]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 2
+- expression 0 operands: lhs = Counter(0), rhs = Counter(1)
+- expression 1 operands: lhs = Counter(1), rhs = Expression(0, Sub)
+Number of file 0 mappings: 4
+- Code(Counter(0)) at (prev + 51, 5) to (start + 1, 24)
+- Code(Counter(1)) at (prev + 2, 13) to (start + 0, 20)
+- Code(Expression(0, Sub)) at (prev + 2, 13) to (start + 0, 19)
+    = (c0 - c1)
+- Code(Expression(1, Add)) at (prev + 2, 5) to (start + 0, 6)
+    = (c1 + (c0 - c1))
+
+Function name: try_error_result::call
+Raw bytes (28): 0x[01, 01, 02, 01, 05, 05, 02, 04, 01, 04, 01, 01, 14, 05, 02, 09, 00, 10, 02, 02, 09, 00, 0f, 07, 02, 01, 00, 02]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 2
+- expression 0 operands: lhs = Counter(0), rhs = Counter(1)
+- expression 1 operands: lhs = Counter(1), rhs = Expression(0, Sub)
+Number of file 0 mappings: 4
+- Code(Counter(0)) at (prev + 4, 1) to (start + 1, 20)
+- Code(Counter(1)) at (prev + 2, 9) to (start + 0, 16)
+- Code(Expression(0, Sub)) at (prev + 2, 9) to (start + 0, 15)
+    = (c0 - c1)
+- Code(Expression(1, Add)) at (prev + 2, 1) to (start + 0, 2)
+    = (c1 + (c0 - c1))
+
+Function name: try_error_result::main
+Raw bytes (28): 0x[01, 01, 02, 01, 05, 05, 02, 04, 01, 70, 01, 02, 0c, 05, 03, 05, 00, 06, 02, 02, 05, 00, 0b, 07, 01, 01, 00, 02]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 2
+- expression 0 operands: lhs = Counter(0), rhs = Counter(1)
+- expression 1 operands: lhs = Counter(1), rhs = Expression(0, Sub)
+Number of file 0 mappings: 4
+- Code(Counter(0)) at (prev + 112, 1) to (start + 2, 12)
+- Code(Counter(1)) at (prev + 3, 5) to (start + 0, 6)
+- Code(Expression(0, Sub)) at (prev + 2, 5) to (start + 0, 11)
+    = (c0 - c1)
+- Code(Expression(1, Add)) at (prev + 1, 1) to (start + 0, 2)
+    = (c1 + (c0 - c1))
+
+Function name: try_error_result::test1
+Raw bytes (77): 0x[01, 01, 09, 01, 07, 05, 09, 03, 0d, 1d, 11, 16, 1d, 03, 0d, 1f, 0d, 11, 23, 15, 19, 0b, 01, 0c, 01, 02, 17, 03, 07, 09, 00, 0e, 16, 02, 09, 04, 1a, 1d, 06, 0d, 00, 29, 11, 00, 29, 00, 2a, 0e, 01, 0d, 00, 2a, 15, 00, 2a, 00, 2b, 12, 04, 0d, 00, 2a, 19, 00, 2a, 00, 2b, 0d, 03, 05, 00, 0b, 1b, 01, 01, 00, 02]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 9
+- expression 0 operands: lhs = Counter(0), rhs = Expression(1, Add)
+- expression 1 operands: lhs = Counter(1), rhs = Counter(2)
+- expression 2 operands: lhs = Expression(0, Add), rhs = Counter(3)
+- expression 3 operands: lhs = Counter(7), rhs = Counter(4)
+- expression 4 operands: lhs = Expression(5, Sub), rhs = Counter(7)
+- expression 5 operands: lhs = Expression(0, Add), rhs = Counter(3)
+- expression 6 operands: lhs = Expression(7, Add), rhs = Counter(3)
+- expression 7 operands: lhs = Counter(4), rhs = Expression(8, Add)
+- expression 8 operands: lhs = Counter(5), rhs = Counter(6)
+Number of file 0 mappings: 11
+- Code(Counter(0)) at (prev + 12, 1) to (start + 2, 23)
+- Code(Expression(0, Add)) at (prev + 7, 9) to (start + 0, 14)
+    = (c0 + (c1 + c2))
+- Code(Expression(5, Sub)) at (prev + 2, 9) to (start + 4, 26)
+    = ((c0 + (c1 + c2)) - c3)
+- Code(Counter(7)) at (prev + 6, 13) to (start + 0, 41)
+- Code(Counter(4)) at (prev + 0, 41) to (start + 0, 42)
+- Code(Expression(3, Sub)) at (prev + 1, 13) to (start + 0, 42)
+    = (c7 - c4)
+- Code(Counter(5)) at (prev + 0, 42) to (start + 0, 43)
+- Code(Expression(4, Sub)) at (prev + 4, 13) to (start + 0, 42)
+    = (((c0 + (c1 + c2)) - c3) - c7)
+- Code(Counter(6)) at (prev + 0, 42) to (start + 0, 43)
+- Code(Counter(3)) at (prev + 3, 5) to (start + 0, 11)
+- Code(Expression(6, Add)) at (prev + 1, 1) to (start + 0, 2)
+    = ((c4 + (c5 + c6)) + c3)
+
+Function name: try_error_result::test2
+Raw bytes (373): 0x[01, 01, 41, 01, 07, 05, 09, 03, 0d, 41, 11, 52, 15, 41, 11, 4a, 1d, 4e, 19, 52, 15, 41, 11, 4e, 00, 52, 15, 41, 11, 4e, 19, 52, 15, 41, 11, 46, 00, 4a, 1d, 4e, 19, 52, 15, 41, 11, 6a, 25, 49, 21, 49, 21, 66, 00, 6a, 25, 49, 21, 9a, 01, 2d, 9e, 01, 29, a2, 01, 41, 03, 0d, a2, 01, 41, 03, 0d, 9e, 01, 29, a2, 01, 41, 03, 0d, 96, 01, 00, 9a, 01, 2d, 9e, 01, 29, a2, 01, 41, 03, 0d, ba, 01, 35, 45, 31, 45, 31, b6, 01, 00, ba, 01, 35, 45, 31, d2, 01, 3d, 4d, 39, 4d, 39, ce, 01, 00, d2, 01, 3d, 4d, 39, db, 01, 0d, 11, df, 01, e3, 01, f3, 01, 15, e7, 01, eb, 01, ef, 01, 19, 1d, 21, 25, f7, 01, fb, 01, 29, 2d, ff, 01, 83, 02, 31, 35, 39, 3d, 28, 01, 3c, 01, 03, 17, 03, 08, 09, 00, 0e, a2, 01, 02, 09, 04, 1a, 41, 06, 0d, 00, 2f, 11, 00, 2f, 00, 30, 52, 00, 31, 03, 35, 15, 04, 11, 00, 12, 4e, 02, 11, 04, 12, 46, 05, 11, 00, 14, 2b, 00, 17, 00, 41, 19, 00, 41, 00, 42, 4a, 00, 43, 00, 5f, 1d, 00, 5f, 00, 60, 43, 01, 0d, 00, 20, 66, 01, 11, 00, 14, 49, 00, 17, 00, 41, 21, 00, 41, 00, 42, 6a, 00, 43, 00, 60, 25, 00, 60, 00, 61, 63, 01, 0d, 00, 20, 96, 01, 04, 11, 00, 14, 9e, 01, 00, 17, 00, 42, 29, 00, 42, 00, 43, 9a, 01, 00, 44, 00, 61, 2d, 00, 61, 00, 62, 93, 01, 01, 0d, 00, 20, b6, 01, 01, 11, 00, 14, 45, 00, 17, 01, 36, 31, 01, 36, 00, 37, ba, 01, 01, 12, 00, 2f, 35, 00, 2f, 00, 30, b3, 01, 01, 0d, 00, 20, ce, 01, 01, 11, 00, 14, 4d, 00, 17, 01, 36, 39, 02, 11, 00, 12, d2, 01, 01, 12, 00, 2f, 3d, 01, 11, 00, 12, cb, 01, 02, 0d, 00, 20, 0d, 03, 05, 00, 0b, d7, 01, 01, 01, 00, 02]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 65
+- expression 0 operands: lhs = Counter(0), rhs = Expression(1, Add)
+- expression 1 operands: lhs = Counter(1), rhs = Counter(2)
+- expression 2 operands: lhs = Expression(0, Add), rhs = Counter(3)
+- expression 3 operands: lhs = Counter(16), rhs = Counter(4)
+- expression 4 operands: lhs = Expression(20, Sub), rhs = Counter(5)
+- expression 5 operands: lhs = Counter(16), rhs = Counter(4)
+- expression 6 operands: lhs = Expression(18, Sub), rhs = Counter(7)
+- expression 7 operands: lhs = Expression(19, Sub), rhs = Counter(6)
+- expression 8 operands: lhs = Expression(20, Sub), rhs = Counter(5)
+- expression 9 operands: lhs = Counter(16), rhs = Counter(4)
+- expression 10 operands: lhs = Expression(19, Sub), rhs = Zero
+- expression 11 operands: lhs = Expression(20, Sub), rhs = Counter(5)
+- expression 12 operands: lhs = Counter(16), rhs = Counter(4)
+- expression 13 operands: lhs = Expression(19, Sub), rhs = Counter(6)
+- expression 14 operands: lhs = Expression(20, Sub), rhs = Counter(5)
+- expression 15 operands: lhs = Counter(16), rhs = Counter(4)
+- expression 16 operands: lhs = Expression(17, Sub), rhs = Zero
+- expression 17 operands: lhs = Expression(18, Sub), rhs = Counter(7)
+- expression 18 operands: lhs = Expression(19, Sub), rhs = Counter(6)
+- expression 19 operands: lhs = Expression(20, Sub), rhs = Counter(5)
+- expression 20 operands: lhs = Counter(16), rhs = Counter(4)
+- expression 21 operands: lhs = Expression(26, Sub), rhs = Counter(9)
+- expression 22 operands: lhs = Counter(18), rhs = Counter(8)
+- expression 23 operands: lhs = Counter(18), rhs = Counter(8)
+- expression 24 operands: lhs = Expression(25, Sub), rhs = Zero
+- expression 25 operands: lhs = Expression(26, Sub), rhs = Counter(9)
+- expression 26 operands: lhs = Counter(18), rhs = Counter(8)
+- expression 27 operands: lhs = Expression(38, Sub), rhs = Counter(11)
+- expression 28 operands: lhs = Expression(39, Sub), rhs = Counter(10)
+- expression 29 operands: lhs = Expression(40, Sub), rhs = Counter(16)
+- expression 30 operands: lhs = Expression(0, Add), rhs = Counter(3)
+- expression 31 operands: lhs = Expression(40, Sub), rhs = Counter(16)
+- expression 32 operands: lhs = Expression(0, Add), rhs = Counter(3)
+- expression 33 operands: lhs = Expression(39, Sub), rhs = Counter(10)
+- expression 34 operands: lhs = Expression(40, Sub), rhs = Counter(16)
+- expression 35 operands: lhs = Expression(0, Add), rhs = Counter(3)
+- expression 36 operands: lhs = Expression(37, Sub), rhs = Zero
+- expression 37 operands: lhs = Expression(38, Sub), rhs = Counter(11)
+- expression 38 operands: lhs = Expression(39, Sub), rhs = Counter(10)
+- expression 39 operands: lhs = Expression(40, Sub), rhs = Counter(16)
+- expression 40 operands: lhs = Expression(0, Add), rhs = Counter(3)
+- expression 41 operands: lhs = Expression(46, Sub), rhs = Counter(13)
+- expression 42 operands: lhs = Counter(17), rhs = Counter(12)
+- expression 43 operands: lhs = Counter(17), rhs = Counter(12)
+- expression 44 operands: lhs = Expression(45, Sub), rhs = Zero
+- expression 45 operands: lhs = Expression(46, Sub), rhs = Counter(13)
+- expression 46 operands: lhs = Counter(17), rhs = Counter(12)
+- expression 47 operands: lhs = Expression(52, Sub), rhs = Counter(15)
+- expression 48 operands: lhs = Counter(19), rhs = Counter(14)
+- expression 49 operands: lhs = Counter(19), rhs = Counter(14)
+- expression 50 operands: lhs = Expression(51, Sub), rhs = Zero
+- expression 51 operands: lhs = Expression(52, Sub), rhs = Counter(15)
+- expression 52 operands: lhs = Counter(19), rhs = Counter(14)
+- expression 53 operands: lhs = Expression(54, Add), rhs = Counter(3)
+- expression 54 operands: lhs = Counter(4), rhs = Expression(55, Add)
+- expression 55 operands: lhs = Expression(56, Add), rhs = Expression(60, Add)
+- expression 56 operands: lhs = Counter(5), rhs = Expression(57, Add)
+- expression 57 operands: lhs = Expression(58, Add), rhs = Expression(59, Add)
+- expression 58 operands: lhs = Counter(6), rhs = Counter(7)
+- expression 59 operands: lhs = Counter(8), rhs = Counter(9)
+- expression 60 operands: lhs = Expression(61, Add), rhs = Expression(62, Add)
+- expression 61 operands: lhs = Counter(10), rhs = Counter(11)
+- expression 62 operands: lhs = Expression(63, Add), rhs = Expression(64, Add)
+- expression 63 operands: lhs = Counter(12), rhs = Counter(13)
+- expression 64 operands: lhs = Counter(14), rhs = Counter(15)
+Number of file 0 mappings: 40
+- Code(Counter(0)) at (prev + 60, 1) to (start + 3, 23)
+- Code(Expression(0, Add)) at (prev + 8, 9) to (start + 0, 14)
+    = (c0 + (c1 + c2))
+- Code(Expression(40, Sub)) at (prev + 2, 9) to (start + 4, 26)
+    = ((c0 + (c1 + c2)) - c3)
+- Code(Counter(16)) at (prev + 6, 13) to (start + 0, 47)
+- Code(Counter(4)) at (prev + 0, 47) to (start + 0, 48)
+- Code(Expression(20, Sub)) at (prev + 0, 49) to (start + 3, 53)
+    = (c16 - c4)
+- Code(Counter(5)) at (prev + 4, 17) to (start + 0, 18)
+- Code(Expression(19, Sub)) at (prev + 2, 17) to (start + 4, 18)
+    = ((c16 - c4) - c5)
+- Code(Expression(17, Sub)) at (prev + 5, 17) to (start + 0, 20)
+    = ((((c16 - c4) - c5) - c6) - c7)
+- Code(Expression(10, Add)) at (prev + 0, 23) to (start + 0, 65)
+    = (((c16 - c4) - c5) + Zero)
+- Code(Counter(6)) at (prev + 0, 65) to (start + 0, 66)
+- Code(Expression(18, Sub)) at (prev + 0, 67) to (start + 0, 95)
+    = (((c16 - c4) - c5) - c6)
+- Code(Counter(7)) at (prev + 0, 95) to (start + 0, 96)
+- Code(Expression(16, Add)) at (prev + 1, 13) to (start + 0, 32)
+    = (((((c16 - c4) - c5) - c6) - c7) + Zero)
+- Code(Expression(25, Sub)) at (prev + 1, 17) to (start + 0, 20)
+    = ((c18 - c8) - c9)
+- Code(Counter(18)) at (prev + 0, 23) to (start + 0, 65)
+- Code(Counter(8)) at (prev + 0, 65) to (start + 0, 66)
+- Code(Expression(26, Sub)) at (prev + 0, 67) to (start + 0, 96)
+    = (c18 - c8)
+- Code(Counter(9)) at (prev + 0, 96) to (start + 0, 97)
+- Code(Expression(24, Add)) at (prev + 1, 13) to (start + 0, 32)
+    = (((c18 - c8) - c9) + Zero)
+- Code(Expression(37, Sub)) at (prev + 4, 17) to (start + 0, 20)
+    = (((((c0 + (c1 + c2)) - c3) - c16) - c10) - c11)
+- Code(Expression(39, Sub)) at (prev + 0, 23) to (start + 0, 66)
+    = (((c0 + (c1 + c2)) - c3) - c16)
+- Code(Counter(10)) at (prev + 0, 66) to (start + 0, 67)
+- Code(Expression(38, Sub)) at (prev + 0, 68) to (start + 0, 97)
+    = ((((c0 + (c1 + c2)) - c3) - c16) - c10)
+- Code(Counter(11)) at (prev + 0, 97) to (start + 0, 98)
+- Code(Expression(36, Add)) at (prev + 1, 13) to (start + 0, 32)
+    = ((((((c0 + (c1 + c2)) - c3) - c16) - c10) - c11) + Zero)
+- Code(Expression(45, Sub)) at (prev + 1, 17) to (start + 0, 20)
+    = ((c17 - c12) - c13)
+- Code(Counter(17)) at (prev + 0, 23) to (start + 1, 54)
+- Code(Counter(12)) at (prev + 1, 54) to (start + 0, 55)
+- Code(Expression(46, Sub)) at (prev + 1, 18) to (start + 0, 47)
+    = (c17 - c12)
+- Code(Counter(13)) at (prev + 0, 47) to (start + 0, 48)
+- Code(Expression(44, Add)) at (prev + 1, 13) to (start + 0, 32)
+    = (((c17 - c12) - c13) + Zero)
+- Code(Expression(51, Sub)) at (prev + 1, 17) to (start + 0, 20)
+    = ((c19 - c14) - c15)
+- Code(Counter(19)) at (prev + 0, 23) to (start + 1, 54)
+- Code(Counter(14)) at (prev + 2, 17) to (start + 0, 18)
+- Code(Expression(52, Sub)) at (prev + 1, 18) to (start + 0, 47)
+    = (c19 - c14)
+- Code(Counter(15)) at (prev + 1, 17) to (start + 0, 18)
+- Code(Expression(50, Add)) at (prev + 2, 13) to (start + 0, 32)
+    = (((c19 - c14) - c15) + Zero)
+- Code(Counter(3)) at (prev + 3, 5) to (start + 0, 11)
+- Code(Expression(53, Add)) at (prev + 1, 1) to (start + 0, 2)
+    = ((c4 + ((c5 + ((c6 + c7) + (c8 + c9))) + ((c10 + c11) + ((c12 + c13) + (c14 + c15))))) + c3)
+

tests/coverage-map/status-quo/try_error_result.rs

@@ -0,0 +1,118 @@
+#![allow(unused_assignments)]
+// failure-status: 1
+
+fn call(return_error: bool) -> Result<(), ()> {
+    if return_error {
+        Err(())
+    } else {
+        Ok(())
+    }
+}
+
+fn test1() -> Result<(), ()> {
+    let mut
+        countdown = 10
+    ;
+    for
+        _
+    in
+        0..10
+    {
+        countdown
+            -= 1
+        ;
+        if
+            countdown < 5
+        {
+            call(/*return_error=*/ true)?;
+            call(/*return_error=*/ false)?;
+        }
+        else
+        {
+            call(/*return_error=*/ false)?;
+        }
+    }
+    Ok(())
+}
+
+struct Thing1;
+impl Thing1 {
+    fn get_thing_2(&self, return_error: bool) -> Result<Thing2, ()> {
+        if return_error {
+            Err(())
+        } else {
+            Ok(Thing2 {})
+        }
+    }
+}
+
+struct Thing2;
+impl Thing2 {
+    fn call(&self, return_error: bool) -> Result<u32, ()> {
+        if return_error {
+            Err(())
+        } else {
+            Ok(57)
+        }
+    }
+}
+
+fn test2() -> Result<(), ()> {
+    let thing1 = Thing1{};
+    let mut
+        countdown = 10
+    ;
+    for
+        _
+    in
+        0..10
+    {
+        countdown
+            -= 1
+        ;
+        if
+            countdown < 5
+        {
+            thing1.get_thing_2(/*err=*/ false)?.call(/*err=*/ true).expect_err("call should fail");
+            thing1
+                .
+                get_thing_2(/*return_error=*/ false)
+                ?
+                .
+                call(/*return_error=*/ true)
+                .
+                expect_err(
+                    "call should fail"
+                );
+            let val = thing1.get_thing_2(/*return_error=*/ true)?.call(/*return_error=*/ true)?;
+            assert_eq!(val, 57);
+            let val = thing1.get_thing_2(/*return_error=*/ true)?.call(/*return_error=*/ false)?;
+            assert_eq!(val, 57);
+        }
+        else
+        {
+            let val = thing1.get_thing_2(/*return_error=*/ false)?.call(/*return_error=*/ false)?;
+            assert_eq!(val, 57);
+            let val = thing1
+                .get_thing_2(/*return_error=*/ false)?
+                .call(/*return_error=*/ false)?;
+            assert_eq!(val, 57);
+            let val = thing1
+                .get_thing_2(/*return_error=*/ false)
+                ?
+                .call(/*return_error=*/ false)
+                ?
+                ;
+            assert_eq!(val, 57);
+        }
+    }
+    Ok(())
+}
+
+fn main() -> Result<(), ()> {
+    test1().expect_err("test1 should fail");
+    test2()
+    ?
+    ;
+    Ok(())
+}

tests/coverage-map/status-quo/unused.cov-map

@@ -0,0 +1,94 @@
+Function name: unused::foo::<f32>
+Raw bytes (42): 0x[01, 01, 04, 01, 0f, 05, 09, 03, 0d, 05, 09, 06, 01, 03, 01, 01, 12, 03, 02, 0b, 00, 11, 0a, 01, 09, 00, 0f, 09, 00, 13, 00, 19, 0f, 01, 09, 00, 0f, 0d, 02, 01, 00, 02]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 4
+- expression 0 operands: lhs = Counter(0), rhs = Expression(3, Add)
+- expression 1 operands: lhs = Counter(1), rhs = Counter(2)
+- expression 2 operands: lhs = Expression(0, Add), rhs = Counter(3)
+- expression 3 operands: lhs = Counter(1), rhs = Counter(2)
+Number of file 0 mappings: 6
+- Code(Counter(0)) at (prev + 3, 1) to (start + 1, 18)
+- Code(Expression(0, Add)) at (prev + 2, 11) to (start + 0, 17)
+    = (c0 + (c1 + c2))
+- Code(Expression(2, Sub)) at (prev + 1, 9) to (start + 0, 15)
+    = ((c0 + (c1 + c2)) - c3)
+- Code(Counter(2)) at (prev + 0, 19) to (start + 0, 25)
+- Code(Expression(3, Add)) at (prev + 1, 9) to (start + 0, 15)
+    = (c1 + c2)
+- Code(Counter(3)) at (prev + 2, 1) to (start + 0, 2)
+
+Function name: unused::foo::<u32>
+Raw bytes (42): 0x[01, 01, 04, 01, 0f, 05, 09, 03, 0d, 05, 09, 06, 01, 03, 01, 01, 12, 03, 02, 0b, 00, 11, 0a, 01, 09, 00, 0f, 09, 00, 13, 00, 19, 0f, 01, 09, 00, 0f, 0d, 02, 01, 00, 02]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 4
+- expression 0 operands: lhs = Counter(0), rhs = Expression(3, Add)
+- expression 1 operands: lhs = Counter(1), rhs = Counter(2)
+- expression 2 operands: lhs = Expression(0, Add), rhs = Counter(3)
+- expression 3 operands: lhs = Counter(1), rhs = Counter(2)
+Number of file 0 mappings: 6
+- Code(Counter(0)) at (prev + 3, 1) to (start + 1, 18)
+- Code(Expression(0, Add)) at (prev + 2, 11) to (start + 0, 17)
+    = (c0 + (c1 + c2))
+- Code(Expression(2, Sub)) at (prev + 1, 9) to (start + 0, 15)
+    = ((c0 + (c1 + c2)) - c3)
+- Code(Counter(2)) at (prev + 0, 19) to (start + 0, 25)
+- Code(Expression(3, Add)) at (prev + 1, 9) to (start + 0, 15)
+    = (c1 + c2)
+- Code(Counter(3)) at (prev + 2, 1) to (start + 0, 2)
+
+Function name: unused::main
+Raw bytes (9): 0x[01, 01, 00, 01, 01, 25, 01, 04, 02]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 0
+Number of file 0 mappings: 1
+- Code(Counter(0)) at (prev + 37, 1) to (start + 4, 2)
+
+Function name: unused::unused_func (unused)
+Raw bytes (24): 0x[01, 01, 00, 04, 01, 13, 01, 01, 0e, 00, 01, 0f, 02, 06, 00, 02, 06, 00, 07, 00, 01, 01, 00, 02]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 0
+Number of file 0 mappings: 4
+- Code(Counter(0)) at (prev + 19, 1) to (start + 1, 14)
+- Code(Zero) at (prev + 1, 15) to (start + 2, 6)
+- Code(Zero) at (prev + 2, 6) to (start + 0, 7)
+- Code(Zero) at (prev + 1, 1) to (start + 0, 2)
+
+Function name: unused::unused_func2 (unused)
+Raw bytes (24): 0x[01, 01, 00, 04, 01, 19, 01, 01, 0e, 00, 01, 0f, 02, 06, 00, 02, 06, 00, 07, 00, 01, 01, 00, 02]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 0
+Number of file 0 mappings: 4
+- Code(Counter(0)) at (prev + 25, 1) to (start + 1, 14)
+- Code(Zero) at (prev + 1, 15) to (start + 2, 6)
+- Code(Zero) at (prev + 2, 6) to (start + 0, 7)
+- Code(Zero) at (prev + 1, 1) to (start + 0, 2)
+
+Function name: unused::unused_func3 (unused)
+Raw bytes (24): 0x[01, 01, 00, 04, 01, 1f, 01, 01, 0e, 00, 01, 0f, 02, 06, 00, 02, 06, 00, 07, 00, 01, 01, 00, 02]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 0
+Number of file 0 mappings: 4
+- Code(Counter(0)) at (prev + 31, 1) to (start + 1, 14)
+- Code(Zero) at (prev + 1, 15) to (start + 2, 6)
+- Code(Zero) at (prev + 2, 6) to (start + 0, 7)
+- Code(Zero) at (prev + 1, 1) to (start + 0, 2)
+
+Function name: unused::unused_template_func::<_> (unused)
+Raw bytes (34): 0x[01, 01, 00, 06, 01, 0b, 01, 01, 12, 00, 02, 0b, 00, 11, 00, 01, 09, 00, 0f, 00, 00, 13, 00, 19, 00, 01, 09, 00, 0f, 00, 02, 01, 00, 02]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 0
+Number of file 0 mappings: 6
+- Code(Counter(0)) at (prev + 11, 1) to (start + 1, 18)
+- Code(Zero) at (prev + 2, 11) to (start + 0, 17)
+- Code(Zero) at (prev + 1, 9) to (start + 0, 15)
+- Code(Zero) at (prev + 0, 19) to (start + 0, 25)
+- Code(Zero) at (prev + 1, 9) to (start + 0, 15)
+- Code(Zero) at (prev + 2, 1) to (start + 0, 2)
+

tests/coverage-map/status-quo/unused.rs

@@ -0,0 +1,41 @@
+#![allow(dead_code, unused_assignments, unused_must_use, unused_variables)]
+
+fn foo<T>(x: T) {
+    let mut i = 0;
+    while i < 10 {
+        i != 0 || i != 0;
+        i += 1;
+    }
+}
+
+fn unused_template_func<T>(x: T) {
+    let mut i = 0;
+    while i < 10 {
+        i != 0 || i != 0;
+        i += 1;
+    }
+}
+
+fn unused_func(mut a: u32) {
+    if a != 0 {
+        a += 1;
+    }
+}
+
+fn unused_func2(mut a: u32) {
+    if a != 0 {
+        a += 1;
+    }
+}
+
+fn unused_func3(mut a: u32) {
+    if a != 0 {
+        a += 1;
+    }
+}
+
+fn main() -> Result<(), u8> {
+    foo::<u32>(0);
+    foo::<f32>(0.0);
+    Ok(())
+}

tests/coverage-map/status-quo/while.cov-map

@@ -0,0 +1,15 @@
+Function name: while::main
+Raw bytes (28): 0x[01, 01, 02, 01, 05, 03, 05, 04, 01, 01, 01, 01, 10, 03, 02, 0b, 00, 14, 00, 00, 15, 01, 06, 06, 02, 01, 00, 02]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 2
+- expression 0 operands: lhs = Counter(0), rhs = Counter(1)
+- expression 1 operands: lhs = Expression(0, Add), rhs = Counter(1)
+Number of file 0 mappings: 4
+- Code(Counter(0)) at (prev + 1, 1) to (start + 1, 16)
+- Code(Expression(0, Add)) at (prev + 2, 11) to (start + 0, 20)
+    = (c0 + c1)
+- Code(Zero) at (prev + 0, 21) to (start + 1, 6)
+- Code(Expression(1, Sub)) at (prev + 2, 1) to (start + 0, 2)
+    = ((c0 + c1) - c1)
+

tests/coverage-map/status-quo/while.rs

@@ -0,0 +1,5 @@
+fn main() {
+    let num = 9;
+    while num >= 10 {
+    }
+}

tests/coverage-map/status-quo/while_early_ret.cov-map

@@ -0,0 +1,26 @@
+Function name: while_early_ret::main
+Raw bytes (61): 0x[01, 01, 06, 01, 05, 03, 09, 0e, 05, 03, 09, 17, 09, 0d, 11, 09, 01, 04, 01, 01, 1b, 03, 03, 09, 02, 0a, 0e, 05, 0d, 02, 0e, 0a, 06, 15, 02, 16, 0d, 04, 15, 00, 1b, 11, 04, 15, 00, 1b, 05, 03, 0a, 03, 0a, 09, 06, 05, 00, 0b, 13, 01, 01, 00, 02]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 6
+- expression 0 operands: lhs = Counter(0), rhs = Counter(1)
+- expression 1 operands: lhs = Expression(0, Add), rhs = Counter(2)
+- expression 2 operands: lhs = Expression(3, Sub), rhs = Counter(1)
+- expression 3 operands: lhs = Expression(0, Add), rhs = Counter(2)
+- expression 4 operands: lhs = Expression(5, Add), rhs = Counter(2)
+- expression 5 operands: lhs = Counter(3), rhs = Counter(4)
+Number of file 0 mappings: 9
+- Code(Counter(0)) at (prev + 4, 1) to (start + 1, 27)
+- Code(Expression(0, Add)) at (prev + 3, 9) to (start + 2, 10)
+    = (c0 + c1)
+- Code(Expression(3, Sub)) at (prev + 5, 13) to (start + 2, 14)
+    = ((c0 + c1) - c2)
+- Code(Expression(2, Sub)) at (prev + 6, 21) to (start + 2, 22)
+    = (((c0 + c1) - c2) - c1)
+- Code(Counter(3)) at (prev + 4, 21) to (start + 0, 27)
+- Code(Counter(4)) at (prev + 4, 21) to (start + 0, 27)
+- Code(Counter(1)) at (prev + 3, 10) to (start + 3, 10)
+- Code(Counter(2)) at (prev + 6, 5) to (start + 0, 11)
+- Code(Expression(4, Add)) at (prev + 1, 1) to (start + 0, 2)
+    = ((c3 + c4) + c2)
+

tests/coverage-map/status-quo/while_early_ret.rs

@@ -0,0 +1,42 @@
+#![allow(unused_assignments)]
+// failure-status: 1
+
+fn main() -> Result<(), u8> {
+    let mut countdown = 10;
+    while
+        countdown
+            >
+        0
+    {
+        if
+            countdown
+                <
+            5
+        {
+            return
+                if
+                    countdown
+                        >
+                    8
+                {
+                    Ok(())
+                }
+                else
+                {
+                    Err(1)
+                }
+                ;
+        }
+        countdown
+            -=
+        1
+        ;
+    }
+    Ok(())
+}
+
+// ISSUE(77553): Originally, this test had `Err(1)` on line 22 (instead of `Ok(())`) and
+// `std::process::exit(2)` on line 26 (instead of `Err(1)`); and this worked as expected on Linux
+// and MacOS. But on Windows (MSVC, at least), the call to `std::process::exit()` exits the program
+// without saving the InstrProf coverage counters. The use of `std::process:exit()` is not critical
+// to the coverage test for early returns, but this is a limitation that should be fixed.

tests/coverage-map/status-quo/yield.cov-map

@@ -0,0 +1,72 @@
+Function name: yield::main
+Raw bytes (118): 0x[01, 01, 11, 01, 00, 05, 09, 0d, 00, 0d, 11, 32, 15, 0d, 11, 11, 15, 2e, 00, 32, 15, 0d, 11, 2e, 00, 32, 15, 0d, 11, 19, 1d, 21, 00, 25, 29, 2d, 00, 10, 01, 07, 01, 01, 16, 03, 06, 0b, 00, 2e, 0d, 01, 27, 00, 29, 07, 01, 0e, 00, 34, 0b, 02, 0b, 00, 2e, 32, 01, 22, 00, 27, 2e, 00, 2c, 00, 2e, 1b, 01, 0e, 00, 34, 1f, 03, 09, 00, 16, 2b, 07, 0b, 00, 2e, 21, 01, 27, 00, 29, 37, 01, 0e, 00, 34, 3b, 02, 0b, 00, 2e, 2d, 01, 27, 00, 29, 3f, 01, 0e, 00, 34, 43, 02, 01, 00, 02]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 17
+- expression 0 operands: lhs = Counter(0), rhs = Zero
+- expression 1 operands: lhs = Counter(1), rhs = Counter(2)
+- expression 2 operands: lhs = Counter(3), rhs = Zero
+- expression 3 operands: lhs = Counter(3), rhs = Counter(4)
+- expression 4 operands: lhs = Expression(12, Sub), rhs = Counter(5)
+- expression 5 operands: lhs = Counter(3), rhs = Counter(4)
+- expression 6 operands: lhs = Counter(4), rhs = Counter(5)
+- expression 7 operands: lhs = Expression(11, Sub), rhs = Zero
+- expression 8 operands: lhs = Expression(12, Sub), rhs = Counter(5)
+- expression 9 operands: lhs = Counter(3), rhs = Counter(4)
+- expression 10 operands: lhs = Expression(11, Sub), rhs = Zero
+- expression 11 operands: lhs = Expression(12, Sub), rhs = Counter(5)
+- expression 12 operands: lhs = Counter(3), rhs = Counter(4)
+- expression 13 operands: lhs = Counter(6), rhs = Counter(7)
+- expression 14 operands: lhs = Counter(8), rhs = Zero
+- expression 15 operands: lhs = Counter(9), rhs = Counter(10)
+- expression 16 operands: lhs = Counter(11), rhs = Zero
+Number of file 0 mappings: 16
+- Code(Counter(0)) at (prev + 7, 1) to (start + 1, 22)
+- Code(Expression(0, Add)) at (prev + 6, 11) to (start + 0, 46)
+    = (c0 + Zero)
+- Code(Counter(3)) at (prev + 1, 39) to (start + 0, 41)
+- Code(Expression(1, Add)) at (prev + 1, 14) to (start + 0, 52)
+    = (c1 + c2)
+- Code(Expression(2, Add)) at (prev + 2, 11) to (start + 0, 46)
+    = (c3 + Zero)
+- Code(Expression(12, Sub)) at (prev + 1, 34) to (start + 0, 39)
+    = (c3 - c4)
+- Code(Expression(11, Sub)) at (prev + 0, 44) to (start + 0, 46)
+    = ((c3 - c4) - c5)
+- Code(Expression(6, Add)) at (prev + 1, 14) to (start + 0, 52)
+    = (c4 + c5)
+- Code(Expression(7, Add)) at (prev + 3, 9) to (start + 0, 22)
+    = (((c3 - c4) - c5) + Zero)
+- Code(Expression(10, Add)) at (prev + 7, 11) to (start + 0, 46)
+    = (((c3 - c4) - c5) + Zero)
+- Code(Counter(8)) at (prev + 1, 39) to (start + 0, 41)
+- Code(Expression(13, Add)) at (prev + 1, 14) to (start + 0, 52)
+    = (c6 + c7)
+- Code(Expression(14, Add)) at (prev + 2, 11) to (start + 0, 46)
+    = (c8 + Zero)
+- Code(Counter(11)) at (prev + 1, 39) to (start + 0, 41)
+- Code(Expression(15, Add)) at (prev + 1, 14) to (start + 0, 52)
+    = (c9 + c10)
+- Code(Expression(16, Add)) at (prev + 2, 1) to (start + 0, 2)
+    = (c11 + Zero)
+
+Function name: yield::main::{closure#0}
+Raw bytes (14): 0x[01, 01, 00, 02, 01, 08, 1c, 01, 10, 05, 02, 10, 01, 06]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 0
+Number of file 0 mappings: 2
+- Code(Counter(0)) at (prev + 8, 28) to (start + 1, 16)
+- Code(Counter(1)) at (prev + 2, 16) to (start + 1, 6)
+
+Function name: yield::main::{closure#1}
+Raw bytes (24): 0x[01, 01, 00, 04, 01, 16, 1c, 01, 10, 05, 02, 09, 00, 10, 09, 01, 09, 00, 10, 0d, 01, 10, 01, 06]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 0
+Number of file 0 mappings: 4
+- Code(Counter(0)) at (prev + 22, 28) to (start + 1, 16)
+- Code(Counter(1)) at (prev + 2, 9) to (start + 0, 16)
+- Code(Counter(2)) at (prev + 1, 9) to (start + 0, 16)
+- Code(Counter(3)) at (prev + 1, 16) to (start + 1, 6)
+

tests/coverage-map/status-quo/yield.rs

@@ -0,0 +1,37 @@
+#![feature(generators, generator_trait)]
+#![allow(unused_assignments)]
+
+use std::ops::{Generator, GeneratorState};
+use std::pin::Pin;
+
+fn main() {
+    let mut generator = || {
+        yield 1;
+        return "foo";
+    };
+
+    match Pin::new(&mut generator).resume(()) {
+        GeneratorState::Yielded(1) => {}
+        _ => panic!("unexpected value from resume"),
+    }
+    match Pin::new(&mut generator).resume(()) {
+        GeneratorState::Complete("foo") => {}
+        _ => panic!("unexpected value from resume"),
+    }
+
+    let mut generator = || {
+        yield 1;
+        yield 2;
+        yield 3;
+        return "foo";
+    };
+
+    match Pin::new(&mut generator).resume(()) {
+        GeneratorState::Yielded(1) => {}
+        _ => panic!("unexpected value from resume"),
+    }
+    match Pin::new(&mut generator).resume(()) {
+        GeneratorState::Yielded(2) => {}
+        _ => panic!("unexpected value from resume"),
+    }
+}