From 3407fcc12ee1ace7267611c91b579f6f5cfcb01b Mon Sep 17 00:00:00 2001
From: Zalathar <Zalathar@users.noreply.github.com>
Date: Fri, 8 Mar 2024 18:07:04 +1100
Subject: [PATCH] coverage: Add `-Zcoverage-options` for fine control of
coverage
This new nightly-only flag can be used to toggle fine-grained flags that
control the details of coverage instrumentation.
Currently the only supported flag value is `branch` (or `no-branch`), which is
a placeholder for upcoming support for branch coverage. Other flag values can
be added in the future, to prototype proposed new behaviour, or to enable
special non-default behaviour.
---
compiler/rustc_interface/src/tests.rs | 12 +++++----
compiler/rustc_session/src/config.rs | 26 ++++++++++++++-----
compiler/rustc_session/src/options.rs | 21 +++++++++++++++
compiler/rustc_session/src/session.rs | 4 +++
src/doc/rustc/src/instrument-coverage.md | 8 ++++++
.../src/compiler-flags/coverage-options.md | 8 ++++++
.../coverage-options.bad.stderr | 2 ++
.../instrument-coverage/coverage-options.rs | 14 ++++++++++
8 files changed, 84 insertions(+), 11 deletions(-)
create mode 100644 src/doc/unstable-book/src/compiler-flags/coverage-options.md
create mode 100644 tests/ui/instrument-coverage/coverage-options.bad.stderr
create mode 100644 tests/ui/instrument-coverage/coverage-options.rs
diff --git a/compiler/rustc_interface/src/tests.rs b/compiler/rustc_interface/src/tests.rs
index 42fff01c11c..4d8e749d1da 100644
--- a/compiler/rustc_interface/src/tests.rs
+++ b/compiler/rustc_interface/src/tests.rs
@@ -4,11 +4,12 @@ use rustc_data_structures::profiling::TimePassesFormat;
use rustc_errors::{emitter::HumanReadableErrorType, registry, ColorConfig};
use rustc_session::config::{
build_configuration, build_session_options, rustc_optgroups, BranchProtection, CFGuard, Cfg,
- CollapseMacroDebuginfo, DebugInfo, DumpMonoStatsFormat, ErrorOutputType, ExternEntry,
- ExternLocation, Externs, FunctionReturn, InliningThreshold, Input, InstrumentCoverage,
- InstrumentXRay, LinkSelfContained, LinkerPluginLto, LocationDetail, LtoCli, NextSolverConfig,
- OomStrategy, Options, OutFileName, OutputType, OutputTypes, PAuthKey, PacRet, Passes, Polonius,
- ProcMacroExecutionStrategy, Strip, SwitchWithOptPath, SymbolManglingVersion, WasiExecModel,
+ CollapseMacroDebuginfo, CoverageOptions, DebugInfo, DumpMonoStatsFormat, ErrorOutputType,
+ ExternEntry, ExternLocation, Externs, FunctionReturn, InliningThreshold, Input,
+ InstrumentCoverage, InstrumentXRay, LinkSelfContained, LinkerPluginLto, LocationDetail, LtoCli,
+ NextSolverConfig, OomStrategy, Options, OutFileName, OutputType, OutputTypes, PAuthKey, PacRet,
+ Passes, Polonius, ProcMacroExecutionStrategy, Strip, SwitchWithOptPath, SymbolManglingVersion,
+ WasiExecModel,
};
use rustc_session::lint::Level;
use rustc_session::search_paths::SearchPath;
@@ -750,6 +751,7 @@ fn test_unstable_options_tracking_hash() {
);
tracked!(codegen_backend, Some("abc".to_string()));
tracked!(collapse_macro_debuginfo, CollapseMacroDebuginfo::Yes);
+ tracked!(coverage_options, CoverageOptions { branch: true });
tracked!(crate_attr, vec!["abc".to_string()]);
tracked!(cross_crate_inline_threshold, InliningThreshold::Always);
tracked!(debug_info_for_profiling, true);
diff --git a/compiler/rustc_session/src/config.rs b/compiler/rustc_session/src/config.rs
index 0657d283019..5c52ee66128 100644
--- a/compiler/rustc_session/src/config.rs
+++ b/compiler/rustc_session/src/config.rs
@@ -143,6 +143,19 @@ pub enum InstrumentCoverage {
Yes,
}
+/// Individual flag values controlled by `-Z coverage-options`.
+#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
+pub struct CoverageOptions {
+ /// Add branch coverage instrumentation (placeholder flag; not yet implemented).
+ pub branch: bool,
+}
+
+impl Default for CoverageOptions {
+ fn default() -> Self {
+ Self { branch: false }
+ }
+}
+
/// Settings for `-Z instrument-xray` flag.
#[derive(Clone, Copy, Debug, Default, PartialEq, Eq, Hash)]
pub struct InstrumentXRay {
@@ -3168,12 +3181,12 @@ pub enum WasiExecModel {
/// how the hash should be calculated when adding a new command-line argument.
pub(crate) mod dep_tracking {
use super::{
- BranchProtection, CFGuard, CFProtection, CollapseMacroDebuginfo, CrateType, DebugInfo,
- DebugInfoCompression, ErrorOutputType, FunctionReturn, InliningThreshold,
- InstrumentCoverage, InstrumentXRay, LinkerPluginLto, LocationDetail, LtoCli,
- NextSolverConfig, OomStrategy, OptLevel, OutFileName, OutputType, OutputTypes, Polonius,
- RemapPathScopeComponents, ResolveDocLinks, SourceFileHashAlgorithm, SplitDwarfKind,
- SwitchWithOptPath, SymbolManglingVersion, WasiExecModel,
+ BranchProtection, CFGuard, CFProtection, CollapseMacroDebuginfo, CoverageOptions,
+ CrateType, DebugInfo, DebugInfoCompression, ErrorOutputType, FunctionReturn,
+ InliningThreshold, InstrumentCoverage, InstrumentXRay, LinkerPluginLto, LocationDetail,
+ LtoCli, NextSolverConfig, OomStrategy, OptLevel, OutFileName, OutputType, OutputTypes,
+ Polonius, RemapPathScopeComponents, ResolveDocLinks, SourceFileHashAlgorithm,
+ SplitDwarfKind, SwitchWithOptPath, SymbolManglingVersion, WasiExecModel,
};
use crate::lint;
use crate::utils::NativeLib;
@@ -3243,6 +3256,7 @@ pub(crate) mod dep_tracking {
CodeModel,
TlsModel,
InstrumentCoverage,
+ CoverageOptions,
InstrumentXRay,
CrateType,
MergeFunctions,
diff --git a/compiler/rustc_session/src/options.rs b/compiler/rustc_session/src/options.rs
index a51d153225d..ab79e3ecae4 100644
--- a/compiler/rustc_session/src/options.rs
+++ b/compiler/rustc_session/src/options.rs
@@ -396,6 +396,7 @@ mod desc {
pub const parse_optimization_fuel: &str = "crate=integer";
pub const parse_dump_mono_stats: &str = "`markdown` (default) or `json`";
pub const parse_instrument_coverage: &str = parse_bool;
+ pub const parse_coverage_options: &str = "`branch` or `no-branch`";
pub const parse_instrument_xray: &str = "either a boolean (`yes`, `no`, `on`, `off`, etc), or a comma separated list of settings: `always` or `never` (mutually exclusive), `ignore-loops`, `instruction-threshold=N`, `skip-entry`, `skip-exit`";
pub const parse_unpretty: &str = "`string` or `string=string`";
pub const parse_treat_err_as_bug: &str = "either no value or a non-negative number";
@@ -938,6 +939,24 @@ mod parse {
true
}
+ pub(crate) fn parse_coverage_options(slot: &mut CoverageOptions, v: Option<&str>) -> bool {
+ let Some(v) = v else { return true };
+
+ for option in v.split(',') {
+ let (option, enabled) = match option.strip_prefix("no-") {
+ Some(without_no) => (without_no, false),
+ None => (option, true),
+ };
+ let slot = match option {
+ "branch" => &mut slot.branch,
+ _ => return false,
+ };
+ *slot = enabled;
+ }
+
+ true
+ }
+
pub(crate) fn parse_instrument_xray(
slot: &mut Option<InstrumentXRay>,
v: Option<&str>,
@@ -1564,6 +1583,8 @@ options! {
"set option to collapse debuginfo for macros"),
combine_cgu: bool = (false, parse_bool, [TRACKED],
"combine CGUs into a single one"),
+ coverage_options: CoverageOptions = (CoverageOptions::default(), parse_coverage_options, [TRACKED],
+ "control details of coverage instrumentation"),
crate_attr: Vec<String> = (Vec::new(), parse_string_push, [TRACKED],
"inject the given attribute in the crate"),
cross_crate_inline_threshold: InliningThreshold = (InliningThreshold::Sometimes(100), parse_inlining_threshold, [TRACKED],
diff --git a/compiler/rustc_session/src/session.rs b/compiler/rustc_session/src/session.rs
index 10251d6d4ce..9c94fd7027f 100644
--- a/compiler/rustc_session/src/session.rs
+++ b/compiler/rustc_session/src/session.rs
@@ -352,6 +352,10 @@ impl Session {
self.opts.cg.instrument_coverage() != InstrumentCoverage::No
}
+ pub fn instrument_coverage_branch(&self) -> bool {
+ self.instrument_coverage() && self.opts.unstable_opts.coverage_options.branch
+ }
+
pub fn is_sanitizer_cfi_enabled(&self) -> bool {
self.opts.unstable_opts.sanitizer.contains(SanitizerSet::CFI)
}
diff --git a/src/doc/rustc/src/instrument-coverage.md b/src/doc/rustc/src/instrument-coverage.md
index 23cb1e05ed1..7780f2102ba 100644
--- a/src/doc/rustc/src/instrument-coverage.md
+++ b/src/doc/rustc/src/instrument-coverage.md
@@ -346,6 +346,14 @@ $ llvm-cov report \
more fine-grained coverage options are added.
Using this value is currently not recommended.
+## `-Z coverage-options=<options>`
+
+This unstable option provides finer control over some aspects of coverage
+instrumentation. Pass one or more of the following values, separated by commas.
+
+- `branch` or `no-branch`
+ - Placeholder for potential branch coverage support in the future.
+
## Other references
Rust's implementation and workflow for source-based code coverage is based on the same library and tools used to implement [source-based code coverage in Clang]. (This document is partially based on the Clang guide.)
diff --git a/src/doc/unstable-book/src/compiler-flags/coverage-options.md b/src/doc/unstable-book/src/compiler-flags/coverage-options.md
new file mode 100644
index 00000000000..105dce61511
--- /dev/null
+++ b/src/doc/unstable-book/src/compiler-flags/coverage-options.md
@@ -0,0 +1,8 @@
+# `coverage-options`
+
+This option controls details of the coverage instrumentation performed by
+`-C instrument-coverage`.
+
+Multiple options can be passed, separated by commas. Valid options are:
+
+- `branch` or `no-branch`: Placeholder for future branch coverage support.
diff --git a/tests/ui/instrument-coverage/coverage-options.bad.stderr b/tests/ui/instrument-coverage/coverage-options.bad.stderr
new file mode 100644
index 00000000000..ca82dc5bdb9
--- /dev/null
+++ b/tests/ui/instrument-coverage/coverage-options.bad.stderr
@@ -0,0 +1,2 @@
+error: incorrect value `bad` for unstable option `coverage-options` - `branch` or `no-branch` was expected
+
diff --git a/tests/ui/instrument-coverage/coverage-options.rs b/tests/ui/instrument-coverage/coverage-options.rs
new file mode 100644
index 00000000000..a62e0554f76
--- /dev/null
+++ b/tests/ui/instrument-coverage/coverage-options.rs
@@ -0,0 +1,14 @@
+//@ needs-profiler-support
+//@ revisions: branch no-branch bad
+//@ compile-flags -Cinstrument-coverage
+
+//@ [branch] check-pass
+//@ [branch] compile-flags: -Zcoverage-options=branch
+
+//@ [no-branch] check-pass
+//@ [no-branch] compile-flags: -Zcoverage-options=no-branch
+
+//@ [bad] check-fail
+//@ [bad] compile-flags: -Zcoverage-options=bad
+
+fn main() {}