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Auto merge of #116046 - Zalathar:fn-cov-info, r=cjgillot

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coverage: Move most per-function coverage info into `mir::Body`

Currently, all of the coverage information collected by the `InstrumentCoverage` pass is smuggled through MIR in the form of individual `StatementKind::Coverage` statements, which must then be reassembled by coverage codegen.

That's awkward for a number of reasons:
- While some of the coverage statements do care about their specific position in the MIR control-flow graph, many of them don't, and are just tacked onto the function's first BB as metadata carriers.
- MIR inlining can result in coverage statements being duplicated, so coverage codegen has to jump through hoops to avoid emitting duplicate mappings.
- MIR optimizations that would delete coverage statements need to carefully copy them into the function's first BB so as not to omit them from coverage reports.
- The order in which coverage codegen sees coverage statements is dependent on MIR optimizations/inlining, which can cause unnecessary churn in the emitted coverage mappings.
- We don't have a good way to annotate MIR-level functions with extra coverage info that doesn't belong in a statement.

---

This PR therefore takes most of the per-function coverage info and stores it in a field in `mir::Body` as `Option<Box<FunctionCoverageInfo>>`.

(This adds one pointer to the size of `mir::Body`, even when coverage is not enabled.)

Coverage statements still need to be injected into MIR in some cases, but only when they actually affect codegen (counters) or are needed to detect code that has been optimized away as unreachable (counters/expressions).

---

By the end of this PR, the information stored in `FunctionCoverageInfo` is:

- A hash of the function's source code (needed by LLVM's coverage map format)
- The number of coverage counters added by coverage instrumentation
- A table of coverage expressions, associating each expression ID with its operator (add or subtract) and its two operands
- The list of mappings, associating each covered code region with a counter/expression/zero value

---

~~This is built on top of #115301, so I'll rebase and roll a reviewer once that lands.~~
r? `@ghost`
`@rustbot` label +A-code-coverage
This commit is contained in:
bors 2023-10-18 18:48:34 +00:00
commit cc705b8012
26 changed files with 459 additions and 668 deletions
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23
compiler/rustc_codegen_llvm/src/coverageinfo/ffi.rs
View File

@ -1,4 +1,4 @@
use rustc_middle::mir::coverage::{CounterId, ExpressionId, Operand}; use rustc_middle::mir::coverage::{CounterId, CovTerm, ExpressionId};
/// Must match the layout of `LLVMRustCounterKind`. /// Must match the layout of `LLVMRustCounterKind`.
#[derive(Copy, Clone, Debug)] #[derive(Copy, Clone, Debug)]
@ -43,11 +43,11 @@ impl Counter {
Self { kind: CounterKind::Expression, id: expression_id.as_u32() } Self { kind: CounterKind::Expression, id: expression_id.as_u32() }
} }
pub(crate) fn from_operand(operand: Operand) -> Self { pub(crate) fn from_term(term: CovTerm) -> Self {
match operand { match term {
Operand::Zero => Self::ZERO, CovTerm::Zero => Self::ZERO,
Operand::Counter(id) => Self::counter_value_reference(id), CovTerm::Counter(id) => Self::counter_value_reference(id),
Operand::Expression(id) => Self::expression(id), CovTerm::Expression(id) => Self::expression(id),
} }
} }
} }
@ -73,17 +73,6 @@ pub struct CounterExpression {
pub rhs: Counter, pub rhs: Counter,
} }
impl CounterExpression {
/// The dummy expression `(0 - 0)` has a representation of all zeroes,
/// making it marginally more efficient to initialize than `(0 + 0)`.
pub(crate) const DUMMY: Self =
Self { lhs: Counter::ZERO, kind: ExprKind::Subtract, rhs: Counter::ZERO };
pub fn new(lhs: Counter, kind: ExprKind, rhs: Counter) -> Self {
Self { kind, lhs, rhs }
}
}
/// Corresponds to enum `llvm::coverage::CounterMappingRegion::RegionKind`. /// Corresponds to enum `llvm::coverage::CounterMappingRegion::RegionKind`.
/// ///
/// Must match the layout of `LLVMRustCounterMappingRegionKind`. /// Must match the layout of `LLVMRustCounterMappingRegionKind`.

336
compiler/rustc_codegen_llvm/src/coverageinfo/map_data.rs
View File

@ -1,64 +1,78 @@
use crate::coverageinfo::ffi::{Counter, CounterExpression, ExprKind}; use crate::coverageinfo::ffi::{Counter, CounterExpression, ExprKind};
use rustc_data_structures::fx::FxIndexSet; use rustc_data_structures::fx::FxIndexSet;
use rustc_index::IndexVec; use rustc_index::bit_set::BitSet;
use rustc_middle::mir::coverage::{CodeRegion, CounterId, ExpressionId, Op, Operand}; use rustc_middle::mir::coverage::{
CodeRegion, CounterId, CovTerm, Expression, ExpressionId, FunctionCoverageInfo, Mapping, Op,
};
use rustc_middle::ty::Instance; use rustc_middle::ty::Instance;
use rustc_middle::ty::TyCtxt;
#[derive(Clone, Debug, PartialEq)] /// Holds all of the coverage mapping data associated with a function instance,
pub struct Expression { /// collected during traversal of `Coverage` statements in the function's MIR.
lhs: Operand,
op: Op,
rhs: Operand,
code_regions: Vec<CodeRegion>,
}
/// Collects all of the coverage regions associated with (a) injected counters, (b) counter
/// expressions (additions or subtraction), and (c) unreachable regions (always counted as zero),
/// for a given Function. This struct also stores the `function_source_hash`,
/// computed during instrumentation, and forwarded with counters.
///
/// Note, it may be important to understand LLVM's definitions of `unreachable` regions versus "gap
/// regions" (or "gap areas"). A gap region is a code region within a counted region (either counter
/// or expression), but the line or lines in the gap region are not executable (such as lines with
/// only whitespace or comments). According to LLVM Code Coverage Mapping documentation, "A count
/// for a gap area is only used as the line execution count if there are no other regions on a
/// line."
#[derive(Debug)] #[derive(Debug)]
pub struct FunctionCoverage<'tcx> { pub struct FunctionCoverage<'tcx> {
instance: Instance<'tcx>, /// Coverage info that was attached to this function by the instrumentor.
source_hash: u64, function_coverage_info: &'tcx FunctionCoverageInfo,
is_used: bool, is_used: bool,
counters: IndexVec<CounterId, Option<Vec<CodeRegion>>>,
expressions: IndexVec<ExpressionId, Option<Expression>>, /// Tracks which counters have been seen, so that we can identify mappings
unreachable_regions: Vec<CodeRegion>, /// to counters that were optimized out, and set them to zero.
counters_seen: BitSet<CounterId>,
/// Contains all expression IDs that have been seen in an `ExpressionUsed`
/// coverage statement, plus all expression IDs that aren't directly used
/// by any mappings (and therefore do not have expression-used statements).
/// After MIR traversal is finished, we can conclude that any IDs missing
/// from this set must have had their statements deleted by MIR opts.
expressions_seen: BitSet<ExpressionId>,
} }
impl<'tcx> FunctionCoverage<'tcx> { impl<'tcx> FunctionCoverage<'tcx> {
/// Creates a new set of coverage data for a used (called) function. /// Creates a new set of coverage data for a used (called) function.
pub fn new(tcx: TyCtxt<'tcx>, instance: Instance<'tcx>) -> Self { pub fn new(
Self::create(tcx, instance, true) instance: Instance<'tcx>,
function_coverage_info: &'tcx FunctionCoverageInfo,
) -> Self {
Self::create(instance, function_coverage_info, true)
} }
/// Creates a new set of coverage data for an unused (never called) function. /// Creates a new set of coverage data for an unused (never called) function.
pub fn unused(tcx: TyCtxt<'tcx>, instance: Instance<'tcx>) -> Self { pub fn unused(
Self::create(tcx, instance, false) instance: Instance<'tcx>,
function_coverage_info: &'tcx FunctionCoverageInfo,
) -> Self {
Self::create(instance, function_coverage_info, false)
} }
fn create(tcx: TyCtxt<'tcx>, instance: Instance<'tcx>, is_used: bool) -> Self { fn create(
let coverageinfo = tcx.coverageinfo(instance.def); instance: Instance<'tcx>,
function_coverage_info: &'tcx FunctionCoverageInfo,
is_used: bool,
) -> Self {
let num_counters = function_coverage_info.num_counters;
let num_expressions = function_coverage_info.expressions.len();
debug!( debug!(
"FunctionCoverage::create(instance={:?}) has coverageinfo={:?}. is_used={}", "FunctionCoverage::create(instance={instance:?}) has \
instance, coverageinfo, is_used num_counters={num_counters}, num_expressions={num_expressions}, is_used={is_used}"
); );
// Create a filled set of expression IDs, so that expressions not
// directly used by mappings will be treated as "seen".
// (If they end up being unused, LLVM will delete them for us.)
let mut expressions_seen = BitSet::new_filled(num_expressions);
// For each expression ID that is directly used by one or more mappings,
// mark it as not-yet-seen. This indicates that we expect to see a
// corresponding `ExpressionUsed` statement during MIR traversal.
for Mapping { term, .. } in &function_coverage_info.mappings {
if let &CovTerm::Expression(id) = term {
expressions_seen.remove(id);
}
}
Self { Self {
instance, function_coverage_info,
source_hash: 0, // will be set with the first `add_counter()`
is_used, is_used,
counters: IndexVec::from_elem_n(None, coverageinfo.num_counters as usize), counters_seen: BitSet::new_empty(num_counters),
expressions: IndexVec::from_elem_n(None, coverageinfo.num_expressions as usize), expressions_seen,
unreachable_regions: Vec::new(),
} }
} }
@ -67,135 +81,94 @@ impl<'tcx> FunctionCoverage<'tcx> {
self.is_used self.is_used
} }
/// Sets the function source hash value. If called multiple times for the same function, all /// Marks a counter ID as having been seen in a counter-increment statement.
/// calls should have the same hash value.
pub fn set_function_source_hash(&mut self, source_hash: u64) {
if self.source_hash == 0 {
self.source_hash = source_hash;
} else {
debug_assert_eq!(source_hash, self.source_hash);
}
}
/// Adds code regions to be counted by an injected counter intrinsic.
#[instrument(level = "debug", skip(self))] #[instrument(level = "debug", skip(self))]
pub(crate) fn add_counter(&mut self, id: CounterId, code_regions: &[CodeRegion]) { pub(crate) fn mark_counter_id_seen(&mut self, id: CounterId) {
if code_regions.is_empty() { self.counters_seen.insert(id);
return;
} }
let slot = &mut self.counters[id]; /// Marks an expression ID as having been seen in an expression-used statement.
match slot {
None => *slot = Some(code_regions.to_owned()),
// If this counter ID slot has already been filled, it should
// contain identical information.
Some(ref previous_regions) => assert_eq!(
previous_regions, code_regions,
"add_counter: code regions for id changed"
),
}
}
/// Adds information about a coverage expression, along with zero or more
/// code regions mapped to that expression.
///
/// Both counters and "counter expressions" (or simply, "expressions") can be operands in other
/// expressions. These are tracked as separate variants of `Operand`, so there is no ambiguity
/// between operands that are counter IDs and operands that are expression IDs.
#[instrument(level = "debug", skip(self))] #[instrument(level = "debug", skip(self))]
pub(crate) fn add_counter_expression( pub(crate) fn mark_expression_id_seen(&mut self, id: ExpressionId) {
&mut self, self.expressions_seen.insert(id);
expression_id: ExpressionId,
lhs: Operand,
op: Op,
rhs: Operand,
code_regions: &[CodeRegion],
) {
debug_assert!(
expression_id.as_usize() < self.expressions.len(),
"expression_id {} is out of range for expressions.len() = {}
for {:?}",
expression_id.as_usize(),
self.expressions.len(),
self,
);
let expression = Expression { lhs, op, rhs, code_regions: code_regions.to_owned() };
let slot = &mut self.expressions[expression_id];
match slot {
None => *slot = Some(expression),
// If this expression ID slot has already been filled, it should
// contain identical information.
Some(ref previous_expression) => assert_eq!(
previous_expression, &expression,
"add_counter_expression: expression for id changed"
),
}
} }
/// Adds regions that will be marked as "unreachable", with a constant "zero counter". /// Identify expressions that will always have a value of zero, and note
#[instrument(level = "debug", skip(self))] /// their IDs in [`ZeroExpressions`]. Mappings that refer to a zero expression
pub(crate) fn add_unreachable_regions(&mut self, code_regions: &[CodeRegion]) { /// can instead become mappings to a constant zero value.
assert!(!code_regions.is_empty(), "unreachable regions always have code regions");
self.unreachable_regions.extend_from_slice(code_regions);
}
/// Perform some simplifications to make the final coverage mappings
/// slightly smaller.
/// ///
/// This method mainly exists to preserve the simplifications that were /// This method mainly exists to preserve the simplifications that were
/// already being performed by the Rust-side expression renumbering, so that /// already being performed by the Rust-side expression renumbering, so that
/// the resulting coverage mappings don't get worse. /// the resulting coverage mappings don't get worse.
pub(crate) fn simplify_expressions(&mut self) { fn identify_zero_expressions(&self) -> ZeroExpressions {
// The set of expressions that either were optimized out entirely, or // The set of expressions that either were optimized out entirely, or
// have zero as both of their operands, and will therefore always have // have zero as both of their operands, and will therefore always have
// a value of zero. Other expressions that refer to these as operands // a value of zero. Other expressions that refer to these as operands
// can have those operands replaced with `Operand::Zero`. // can have those operands replaced with `CovTerm::Zero`.
let mut zero_expressions = FxIndexSet::default(); let mut zero_expressions = FxIndexSet::default();
// For each expression, perform simplifications based on lower-numbered // Simplify a copy of each expression based on lower-numbered expressions,
// expressions, and then update the set of always-zero expressions if // and then update the set of always-zero expressions if necessary.
// necessary.
// (By construction, expressions can only refer to other expressions // (By construction, expressions can only refer to other expressions
// that have lower IDs, so one simplification pass is sufficient.) // that have lower IDs, so one pass is sufficient.)
for (id, maybe_expression) in self.expressions.iter_enumerated_mut() { for (id, expression) in self.function_coverage_info.expressions.iter_enumerated() {
let Some(expression) = maybe_expression else { if !self.expressions_seen.contains(id) {
// If an expression is missing, it must have been optimized away, // If an expression was not seen, it must have been optimized away,
// so any operand that refers to it can be replaced with zero. // so any operand that refers to it can be replaced with zero.
zero_expressions.insert(id); zero_expressions.insert(id);
continue; continue;
}
// We don't need to simplify the actual expression data in the
// expressions list; we can just simplify a temporary copy and then
// use that to update the set of always-zero expressions.
let Expression { mut lhs, op, mut rhs } = *expression;
// If an expression has an operand that is also an expression, the
// operand's ID must be strictly lower. This is what lets us find
// all zero expressions in one pass.
let assert_operand_expression_is_lower = |operand_id: ExpressionId| {
assert!(
operand_id < id,
"Operand {operand_id:?} should be less than {id:?} in {expression:?}",
)
}; };
// If an operand refers to an expression that is always zero, then // If an operand refers to an expression that is always zero, then
// that operand can be replaced with `Operand::Zero`. // that operand can be replaced with `CovTerm::Zero`.
let maybe_set_operand_to_zero = |operand: &mut Operand| match &*operand { let maybe_set_operand_to_zero = |operand: &mut CovTerm| match *operand {
Operand::Expression(id) if zero_expressions.contains(id) => { CovTerm::Expression(id) => {
*operand = Operand::Zero; assert_operand_expression_is_lower(id);
if zero_expressions.contains(&id) {
*operand = CovTerm::Zero;
}
} }
_ => (), _ => (),
}; };
maybe_set_operand_to_zero(&mut expression.lhs); maybe_set_operand_to_zero(&mut lhs);
maybe_set_operand_to_zero(&mut expression.rhs); maybe_set_operand_to_zero(&mut rhs);
// Coverage counter values cannot be negative, so if an expression // Coverage counter values cannot be negative, so if an expression
// involves subtraction from zero, assume that its RHS must also be zero. // involves subtraction from zero, assume that its RHS must also be zero.
// (Do this after simplifications that could set the LHS to zero.) // (Do this after simplifications that could set the LHS to zero.)
if let Expression { lhs: Operand::Zero, op: Op::Subtract, .. } = expression { if lhs == CovTerm::Zero && op == Op::Subtract {
expression.rhs = Operand::Zero; rhs = CovTerm::Zero;
} }
// After the above simplifications, if both operands are zero, then // After the above simplifications, if both operands are zero, then
// we know that this expression is always zero too. // we know that this expression is always zero too.
if let Expression { lhs: Operand::Zero, rhs: Operand::Zero, .. } = expression { if lhs == CovTerm::Zero && rhs == CovTerm::Zero {
zero_expressions.insert(id); zero_expressions.insert(id);
} }
} }
ZeroExpressions(zero_expressions)
} }
/// Return the source hash, generated from the HIR node structure, and used to indicate whether /// Return the source hash, generated from the HIR node structure, and used to indicate whether
/// or not the source code structure changed between different compilations. /// or not the source code structure changed between different compilations.
pub fn source_hash(&self) -> u64 { pub fn source_hash(&self) -> u64 {
self.source_hash if self.is_used { self.function_coverage_info.function_source_hash } else { 0 }
} }
/// Generate an array of CounterExpressions, and an iterator over all `Counter`s and their /// Generate an array of CounterExpressions, and an iterator over all `Counter`s and their
@ -204,91 +177,80 @@ impl<'tcx> FunctionCoverage<'tcx> {
pub fn get_expressions_and_counter_regions( pub fn get_expressions_and_counter_regions(
&self, &self,
) -> (Vec<CounterExpression>, impl Iterator<Item = (Counter, &CodeRegion)>) { ) -> (Vec<CounterExpression>, impl Iterator<Item = (Counter, &CodeRegion)>) {
assert!( let zero_expressions = self.identify_zero_expressions();
self.source_hash != 0 || !self.is_used,
"No counters provided the source_hash for used function: {:?}",
self.instance
);
let counter_expressions = self.counter_expressions(); let counter_expressions = self.counter_expressions(&zero_expressions);
// Expression IDs are indices into `self.expressions`, and on the LLVM // Expression IDs are indices into `self.expressions`, and on the LLVM
// side they will be treated as indices into `counter_expressions`, so // side they will be treated as indices into `counter_expressions`, so
// the two vectors should correspond 1:1. // the two vectors should correspond 1:1.
assert_eq!(self.expressions.len(), counter_expressions.len()); assert_eq!(self.function_coverage_info.expressions.len(), counter_expressions.len());
let counter_regions = self.counter_regions(); let counter_regions = self.counter_regions(zero_expressions);
let expression_regions = self.expression_regions();
let unreachable_regions = self.unreachable_regions();
let counter_regions =
counter_regions.chain(expression_regions.into_iter().chain(unreachable_regions));
(counter_expressions, counter_regions) (counter_expressions, counter_regions)
} }
fn counter_regions(&self) -> impl Iterator<Item = (Counter, &CodeRegion)> {
self.counters
.iter_enumerated()
// Filter out counter IDs that we never saw during MIR traversal.
// This can happen if a counter was optimized out by MIR transforms
// (and replaced with `CoverageKind::Unreachable` instead).
.filter_map(|(id, maybe_code_regions)| Some((id, maybe_code_regions.as_ref()?)))
.flat_map(|(id, code_regions)| {
let counter = Counter::counter_value_reference(id);
code_regions.iter().map(move |region| (counter, region))
})
}
/// Convert this function's coverage expression data into a form that can be /// Convert this function's coverage expression data into a form that can be
/// passed through FFI to LLVM. /// passed through FFI to LLVM.
fn counter_expressions(&self) -> Vec<CounterExpression> { fn counter_expressions(&self, zero_expressions: &ZeroExpressions) -> Vec<CounterExpression> {
// We know that LLVM will optimize out any unused expressions before // We know that LLVM will optimize out any unused expressions before
// producing the final coverage map, so there's no need to do the same // producing the final coverage map, so there's no need to do the same
// thing on the Rust side unless we're confident we can do much better. // thing on the Rust side unless we're confident we can do much better.
// (See `CounterExpressionsMinimizer` in `CoverageMappingWriter.cpp`.) // (See `CounterExpressionsMinimizer` in `CoverageMappingWriter.cpp`.)
self.expressions let counter_from_operand = |operand: CovTerm| match operand {
CovTerm::Expression(id) if zero_expressions.contains(id) => Counter::ZERO,
_ => Counter::from_term(operand),
};
self.function_coverage_info
.expressions
.iter() .iter()
.map(|expression| match expression { .map(|&Expression { lhs, op, rhs }| CounterExpression {
None => { lhs: counter_from_operand(lhs),
// This expression ID was allocated, but we never saw the kind: match op {
// actual expression, so it must have been optimized out.
// Replace it with a dummy expression, and let LLVM take
// care of omitting it from the expression list.
CounterExpression::DUMMY
}
&Some(Expression { lhs, op, rhs, .. }) => {
// Convert the operands and operator as normal.
CounterExpression::new(
Counter::from_operand(lhs),
match op {
Op::Add => ExprKind::Add, Op::Add => ExprKind::Add,
Op::Subtract => ExprKind::Subtract, Op::Subtract => ExprKind::Subtract,
}, },
Counter::from_operand(rhs), rhs: counter_from_operand(rhs),
)
}
}) })
.collect::<Vec<_>>() .collect::<Vec<_>>()
} }
fn expression_regions(&self) -> Vec<(Counter, &CodeRegion)> { /// Converts this function's coverage mappings into an intermediate form
// Find all of the expression IDs that weren't optimized out AND have /// that will be used by `mapgen` when preparing for FFI.
// one or more attached code regions, and return the corresponding fn counter_regions(
// mappings as counter/region pairs. &self,
self.expressions zero_expressions: ZeroExpressions,
.iter_enumerated() ) -> impl Iterator<Item = (Counter, &CodeRegion)> {
.filter_map(|(id, maybe_expression)| { // Historically, mappings were stored directly in counter/expression
let code_regions = &maybe_expression.as_ref()?.code_regions; // statements in MIR, and MIR optimizations would sometimes remove them.
Some((id, code_regions)) // That's mostly no longer true, so now we detect cases where that would
// have happened, and zero out the corresponding mappings here instead.
let counter_for_term = move |term: CovTerm| {
let force_to_zero = match term {
CovTerm::Counter(id) => !self.counters_seen.contains(id),
CovTerm::Expression(id) => zero_expressions.contains(id),
CovTerm::Zero => false,
};
if force_to_zero { Counter::ZERO } else { Counter::from_term(term) }
};
self.function_coverage_info.mappings.iter().map(move |mapping| {
let &Mapping { term, ref code_region } = mapping;
let counter = counter_for_term(term);
(counter, code_region)
}) })
.flat_map(|(id, code_regions)| { }
let counter = Counter::expression(id);
code_regions.iter().map(move |code_region| (counter, code_region))
})
.collect::<Vec<_>>()
} }
fn unreachable_regions(&self) -> impl Iterator<Item = (Counter, &CodeRegion)> { /// Set of expression IDs that are known to always evaluate to zero.
self.unreachable_regions.iter().map(|region| (Counter::ZERO, region)) /// Any mapping or expression operand that refers to these expressions can have
/// that reference replaced with a constant zero value.
struct ZeroExpressions(FxIndexSet<ExpressionId>);
impl ZeroExpressions {
fn contains(&self, id: ExpressionId) -> bool {
self.0.contains(&id)
} }
} }

30
compiler/rustc_codegen_llvm/src/coverageinfo/mapgen.rs
View File

@ -10,9 +10,8 @@ use rustc_hir::def::DefKind;
use rustc_hir::def_id::DefId; use rustc_hir::def_id::DefId;
use rustc_index::IndexVec; use rustc_index::IndexVec;
use rustc_middle::bug; use rustc_middle::bug;
use rustc_middle::middle::codegen_fn_attrs::CodegenFnAttrFlags;
use rustc_middle::mir::coverage::CodeRegion; use rustc_middle::mir::coverage::CodeRegion;
use rustc_middle::ty::TyCtxt; use rustc_middle::ty::{self, TyCtxt};
use rustc_span::Symbol; use rustc_span::Symbol;
/// Generates and exports the Coverage Map. /// Generates and exports the Coverage Map.
@ -60,10 +59,8 @@ pub fn finalize(cx: &CodegenCx<'_, '_>) {
// Encode coverage mappings and generate function records // Encode coverage mappings and generate function records
let mut function_data = Vec::new(); let mut function_data = Vec::new();
for (instance, mut function_coverage) in function_coverage_map { for (instance, function_coverage) in function_coverage_map {
debug!("Generate function coverage for {}, {:?}", cx.codegen_unit.name(), instance); debug!("Generate function coverage for {}, {:?}", cx.codegen_unit.name(), instance);
function_coverage.simplify_expressions();
let function_coverage = function_coverage;
let mangled_function_name = tcx.symbol_name(instance).name; let mangled_function_name = tcx.symbol_name(instance).name;
let source_hash = function_coverage.source_hash(); let source_hash = function_coverage.source_hash();
@ -170,10 +167,11 @@ fn encode_mappings_for_function(
let mut virtual_file_mapping = IndexVec::<u32, u32>::new(); let mut virtual_file_mapping = IndexVec::<u32, u32>::new();
let mut mapping_regions = Vec::with_capacity(counter_regions.len()); let mut mapping_regions = Vec::with_capacity(counter_regions.len());
// Sort the list of (counter, region) mapping pairs by region, so that they // Sort and group the list of (counter, region) mapping pairs by filename.
// can be grouped by filename. Prepare file IDs for each filename, and // (Preserve any further ordering imposed by `FunctionCoverage`.)
// prepare the mapping data so that we can pass it through FFI to LLVM. // Prepare file IDs for each filename, and prepare the mapping data so that
counter_regions.sort_by_key(|(_counter, region)| *region); // we can pass it through FFI to LLVM.
counter_regions.sort_by_key(|(_counter, region)| region.file_name);
for counter_regions_for_file in for counter_regions_for_file in
counter_regions.group_by(|(_, a), (_, b)| a.file_name == b.file_name) counter_regions.group_by(|(_, a), (_, b)| a.file_name == b.file_name)
{ {
@ -331,16 +329,14 @@ fn add_unused_functions(cx: &CodegenCx<'_, '_>) {
for non_codegenned_def_id in for non_codegenned_def_id in
eligible_def_ids.into_iter().filter(|id| !codegenned_def_ids.contains(id)) eligible_def_ids.into_iter().filter(|id| !codegenned_def_ids.contains(id))
{ {
let codegen_fn_attrs = tcx.codegen_fn_attrs(non_codegenned_def_id); // Skip any function that didn't have coverage data added to it by the
// coverage instrumentor.
// If a function is marked `#[coverage(off)]`, then skip generating a let body = tcx.instance_mir(ty::InstanceDef::Item(non_codegenned_def_id));
// dead code stub for it. let Some(function_coverage_info) = body.function_coverage_info.as_deref() else {
if codegen_fn_attrs.flags.contains(CodegenFnAttrFlags::NO_COVERAGE) {
debug!("skipping unused fn marked #[coverage(off)]: {:?}", non_codegenned_def_id);
continue; continue;
} };
debug!("generating unused fn: {:?}", non_codegenned_def_id); debug!("generating unused fn: {:?}", non_codegenned_def_id);
cx.define_unused_fn(non_codegenned_def_id); cx.define_unused_fn(non_codegenned_def_id, function_coverage_info);
} }
} }

74
compiler/rustc_codegen_llvm/src/coverageinfo/mod.rs
View File

@ -16,7 +16,7 @@ use rustc_hir as hir;
use rustc_hir::def_id::DefId; use rustc_hir::def_id::DefId;
use rustc_llvm::RustString; use rustc_llvm::RustString;
use rustc_middle::bug; use rustc_middle::bug;
use rustc_middle::mir::coverage::{CounterId, CoverageKind}; use rustc_middle::mir::coverage::{CounterId, CoverageKind, FunctionCoverageInfo};
use rustc_middle::mir::Coverage; use rustc_middle::mir::Coverage;
use rustc_middle::ty; use rustc_middle::ty;
use rustc_middle::ty::layout::{FnAbiOf, HasTyCtxt}; use rustc_middle::ty::layout::{FnAbiOf, HasTyCtxt};
@ -88,44 +88,63 @@ impl<'ll, 'tcx> CodegenCx<'ll, 'tcx> {
/// For used/called functions, the coverageinfo was already added to the /// For used/called functions, the coverageinfo was already added to the
/// `function_coverage_map` (keyed by function `Instance`) during codegen. /// `function_coverage_map` (keyed by function `Instance`) during codegen.
/// But in this case, since the unused function was _not_ previously /// But in this case, since the unused function was _not_ previously
/// codegenned, collect the coverage `CodeRegion`s from the MIR and add /// codegenned, collect the function coverage info from MIR and add an
/// them. Since the function is never called, all of its `CodeRegion`s can be /// "unused" entry to the function coverage map.
/// added as `unreachable_region`s. fn define_unused_fn(&self, def_id: DefId, function_coverage_info: &'tcx FunctionCoverageInfo) {
fn define_unused_fn(&self, def_id: DefId) {
let instance = declare_unused_fn(self, def_id); let instance = declare_unused_fn(self, def_id);
codegen_unused_fn_and_counter(self, instance); codegen_unused_fn_and_counter(self, instance);
add_unused_function_coverage(self, instance, def_id); add_unused_function_coverage(self, instance, function_coverage_info);
} }
} }
impl<'tcx> CoverageInfoBuilderMethods<'tcx> for Builder<'_, '_, 'tcx> { impl<'tcx> CoverageInfoBuilderMethods<'tcx> for Builder<'_, '_, 'tcx> {
#[instrument(level = "debug", skip(self))]
fn add_coverage(&mut self, instance: Instance<'tcx>, coverage: &Coverage) { fn add_coverage(&mut self, instance: Instance<'tcx>, coverage: &Coverage) {
// Our caller should have already taken care of inlining subtleties,
// so we can assume that counter/expression IDs in this coverage
// statement are meaningful for the given instance.
//
// (Either the statement was not inlined and directly belongs to this
// instance, or it was inlined *from* this instance.)
let bx = self; let bx = self;
let Some(function_coverage_info) =
bx.tcx.instance_mir(instance.def).function_coverage_info.as_deref()
else {
debug!("function has a coverage statement but no coverage info");
return;
};
let Some(coverage_context) = bx.coverage_context() else { return }; let Some(coverage_context) = bx.coverage_context() else { return };
let mut coverage_map = coverage_context.function_coverage_map.borrow_mut(); let mut coverage_map = coverage_context.function_coverage_map.borrow_mut();
let func_coverage = coverage_map let func_coverage = coverage_map
.entry(instance) .entry(instance)
.or_insert_with(|| FunctionCoverage::new(bx.tcx(), instance)); .or_insert_with(|| FunctionCoverage::new(instance, function_coverage_info));
let Coverage { kind, code_regions } = coverage; let Coverage { kind } = coverage;
match *kind { match *kind {
CoverageKind::Counter { function_source_hash, id } => { CoverageKind::CounterIncrement { id } => {
debug!( func_coverage.mark_counter_id_seen(id);
"ensuring function source hash is set for instance={:?}; function_source_hash={}",
instance, function_source_hash,
);
func_coverage.set_function_source_hash(function_source_hash);
func_coverage.add_counter(id, code_regions);
// We need to explicitly drop the `RefMut` before calling into `instrprof_increment`, // We need to explicitly drop the `RefMut` before calling into `instrprof_increment`,
// as that needs an exclusive borrow. // as that needs an exclusive borrow.
drop(coverage_map); drop(coverage_map);
let coverageinfo = bx.tcx().coverageinfo(instance.def); // The number of counters passed to `llvm.instrprof.increment` might
// be smaller than the number originally inserted by the instrumentor,
// if some high-numbered counters were removed by MIR optimizations.
// If so, LLVM's profiler runtime will use fewer physical counters.
let num_counters =
bx.tcx().coverage_ids_info(instance.def).max_counter_id.as_u32() + 1;
assert!(
num_counters as usize <= function_coverage_info.num_counters,
"num_counters disagreement: query says {num_counters} but function info only has {}",
function_coverage_info.num_counters
);
let fn_name = bx.get_pgo_func_name_var(instance); let fn_name = bx.get_pgo_func_name_var(instance);
let hash = bx.const_u64(function_source_hash); let hash = bx.const_u64(function_coverage_info.function_source_hash);
let num_counters = bx.const_u32(coverageinfo.num_counters); let num_counters = bx.const_u32(num_counters);
let index = bx.const_u32(id.as_u32()); let index = bx.const_u32(id.as_u32());
debug!( debug!(
"codegen intrinsic instrprof.increment(fn_name={:?}, hash={:?}, num_counters={:?}, index={:?})", "codegen intrinsic instrprof.increment(fn_name={:?}, hash={:?}, num_counters={:?}, index={:?})",
@ -133,11 +152,8 @@ impl<'tcx> CoverageInfoBuilderMethods<'tcx> for Builder<'_, '_, 'tcx> {
); );
bx.instrprof_increment(fn_name, hash, num_counters, index); bx.instrprof_increment(fn_name, hash, num_counters, index);
} }
CoverageKind::Expression { id, lhs, op, rhs } => { CoverageKind::ExpressionUsed { id } => {
func_coverage.add_counter_expression(id, lhs, op, rhs, code_regions); func_coverage.mark_expression_id_seen(id);
}
CoverageKind::Unreachable => {
func_coverage.add_unreachable_regions(code_regions);
} }
} }
} }
@ -200,15 +216,11 @@ fn codegen_unused_fn_and_counter<'tcx>(cx: &CodegenCx<'_, 'tcx>, instance: Insta
fn add_unused_function_coverage<'tcx>( fn add_unused_function_coverage<'tcx>(
cx: &CodegenCx<'_, 'tcx>, cx: &CodegenCx<'_, 'tcx>,
instance: Instance<'tcx>, instance: Instance<'tcx>,
def_id: DefId, function_coverage_info: &'tcx FunctionCoverageInfo,
) { ) {
let tcx = cx.tcx; // An unused function's mappings will automatically be rewritten to map to
// zero, because none of its counters/expressions are marked as seen.
let mut function_coverage = FunctionCoverage::unused(tcx, instance); let function_coverage = FunctionCoverage::unused(instance, function_coverage_info);
for &code_region in tcx.covered_code_regions(def_id) {
let code_region = std::slice::from_ref(code_region);
function_coverage.add_unreachable_regions(code_region);
}
if let Some(coverage_context) = cx.coverage_context() { if let Some(coverage_context) = cx.coverage_context() {
coverage_context.function_coverage_map.borrow_mut().insert(instance, function_coverage); coverage_context.function_coverage_map.borrow_mut().insert(instance, function_coverage);

105
compiler/rustc_middle/src/mir/coverage.rs
View File

@ -1,5 +1,6 @@
//! Metadata from source code coverage analysis and instrumentation. //! Metadata from source code coverage analysis and instrumentation.
use rustc_index::IndexVec;
use rustc_macros::HashStable; use rustc_macros::HashStable;
use rustc_span::Symbol; use rustc_span::Symbol;
@ -8,6 +9,11 @@ use std::fmt::{self, Debug, Formatter};
rustc_index::newtype_index! { rustc_index::newtype_index! {
/// ID of a coverage counter. Values ascend from 0. /// ID of a coverage counter. Values ascend from 0.
/// ///
/// Before MIR inlining, counter IDs are local to their enclosing function.
/// After MIR inlining, coverage statements may have been inlined into
/// another function, so use the statement's source-scope to find which
/// function/instance its IDs are meaningful for.
///
/// Note that LLVM handles counter IDs as `uint32_t`, so there is no need /// Note that LLVM handles counter IDs as `uint32_t`, so there is no need
/// to use a larger representation on the Rust side. /// to use a larger representation on the Rust side.
#[derive(HashStable)] #[derive(HashStable)]
@ -23,6 +29,11 @@ impl CounterId {
rustc_index::newtype_index! { rustc_index::newtype_index! {
/// ID of a coverage-counter expression. Values ascend from 0. /// ID of a coverage-counter expression. Values ascend from 0.
/// ///
/// Before MIR inlining, expression IDs are local to their enclosing function.
/// After MIR inlining, coverage statements may have been inlined into
/// another function, so use the statement's source-scope to find which
/// function/instance its IDs are meaningful for.
///
/// Note that LLVM handles expression IDs as `uint32_t`, so there is no need /// Note that LLVM handles expression IDs as `uint32_t`, so there is no need
/// to use a larger representation on the Rust side. /// to use a larger representation on the Rust side.
#[derive(HashStable)] #[derive(HashStable)]
@ -35,19 +46,21 @@ impl ExpressionId {
pub const START: Self = Self::from_u32(0); pub const START: Self = Self::from_u32(0);
} }
/// Operand of a coverage-counter expression. /// Enum that can hold a constant zero value, the ID of an physical coverage
/// counter, or the ID of a coverage-counter expression.
/// ///
/// Operands can be a constant zero value, an actual coverage counter, or another /// This was originally only used for expression operands (and named `Operand`),
/// expression. Counter/expression operands are referred to by ID. /// but the zero/counter/expression distinction is also useful for representing
/// the value of code/gap mappings, and the true/false arms of branch mappings.
#[derive(Copy, Clone, PartialEq, Eq)] #[derive(Copy, Clone, PartialEq, Eq)]
#[derive(TyEncodable, TyDecodable, Hash, HashStable, TypeFoldable, TypeVisitable)] #[derive(TyEncodable, TyDecodable, Hash, HashStable, TypeFoldable, TypeVisitable)]
pub enum Operand { pub enum CovTerm {
Zero, Zero,
Counter(CounterId), Counter(CounterId),
Expression(ExpressionId), Expression(ExpressionId),
} }
impl Debug for Operand { impl Debug for CovTerm {
fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result { fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
match self { match self {
Self::Zero => write!(f, "Zero"), Self::Zero => write!(f, "Zero"),
@ -59,40 +72,31 @@ impl Debug for Operand {
#[derive(Clone, PartialEq, TyEncodable, TyDecodable, Hash, HashStable, TypeFoldable, TypeVisitable)] #[derive(Clone, PartialEq, TyEncodable, TyDecodable, Hash, HashStable, TypeFoldable, TypeVisitable)]
pub enum CoverageKind { pub enum CoverageKind {
Counter { /// Marks the point in MIR control flow represented by a coverage counter.
function_source_hash: u64, ///
/// ID of this counter within its enclosing function. /// This is eventually lowered to `llvm.instrprof.increment` in LLVM IR.
/// Expressions in the same function can refer to it as an operand. ///
id: CounterId, /// If this statement does not survive MIR optimizations, any mappings that
}, /// refer to this counter can have those references simplified to zero.
Expression { CounterIncrement { id: CounterId },
/// ID of this coverage-counter expression within its enclosing function.
/// Other expressions in the same function can refer to it as an operand. /// Marks the point in MIR control-flow represented by a coverage expression.
id: ExpressionId, ///
lhs: Operand, /// If this statement does not survive MIR optimizations, any mappings that
op: Op, /// refer to this expression can have those references simplified to zero.
rhs: Operand, ///
}, /// (This is only inserted for expression IDs that are directly used by
Unreachable, /// mappings. Intermediate expressions with no direct mappings are
/// retained/zeroed based on whether they are transitively used.)
ExpressionUsed { id: ExpressionId },
} }
impl Debug for CoverageKind { impl Debug for CoverageKind {
fn fmt(&self, fmt: &mut Formatter<'_>) -> fmt::Result { fn fmt(&self, fmt: &mut Formatter<'_>) -> fmt::Result {
use CoverageKind::*; use CoverageKind::*;
match self { match self {
Counter { id, .. } => write!(fmt, "Counter({:?})", id.index()), CounterIncrement { id } => write!(fmt, "CounterIncrement({:?})", id.index()),
Expression { id, lhs, op, rhs } => write!( ExpressionUsed { id } => write!(fmt, "ExpressionUsed({:?})", id.index()),
fmt,
"Expression({:?}) = {:?} {} {:?}",
id.index(),
lhs,
match op {
Op::Add => "+",
Op::Subtract => "-",
},
rhs,
),
Unreachable => write!(fmt, "Unreachable"),
} }
} }
} }
@ -133,3 +137,38 @@ impl Op {
matches!(self, Self::Subtract) matches!(self, Self::Subtract)
} }
} }
#[derive(Clone, Debug)]
#[derive(TyEncodable, TyDecodable, Hash, HashStable, TypeFoldable, TypeVisitable)]
pub struct Expression {
pub lhs: CovTerm,
pub op: Op,
pub rhs: CovTerm,
}
#[derive(Clone, Debug)]
#[derive(TyEncodable, TyDecodable, Hash, HashStable, TypeFoldable, TypeVisitable)]
pub struct Mapping {
pub code_region: CodeRegion,
/// Indicates whether this mapping uses a counter value, expression value,
/// or zero value.
///
/// FIXME: When we add support for mapping kinds other than `Code`
/// (e.g. branch regions, expansion regions), replace this with a dedicated
/// mapping-kind enum.
pub term: CovTerm,
}
/// Stores per-function coverage information attached to a `mir::Body`,
/// to be used in conjunction with the individual coverage statements injected
/// into the function's basic blocks.
#[derive(Clone, Debug)]
#[derive(TyEncodable, TyDecodable, Hash, HashStable, TypeFoldable, TypeVisitable)]
pub struct FunctionCoverageInfo {
pub function_source_hash: u64,
pub num_counters: usize,
pub expressions: IndexVec<ExpressionId, Expression>,
pub mappings: Vec<Mapping>,
}

10
compiler/rustc_middle/src/mir/mod.rs
View File

@ -345,6 +345,14 @@ pub struct Body<'tcx> {
pub injection_phase: Option<MirPhase>, pub injection_phase: Option<MirPhase>,
pub tainted_by_errors: Option<ErrorGuaranteed>, pub tainted_by_errors: Option<ErrorGuaranteed>,
/// Per-function coverage information added by the `InstrumentCoverage`
/// pass, to be used in conjunction with the coverage statements injected
/// into this body's blocks.
///
/// If `-Cinstrument-coverage` is not active, or if an individual function
/// is not eligible for coverage, then this should always be `None`.
pub function_coverage_info: Option<Box<coverage::FunctionCoverageInfo>>,
} }
impl<'tcx> Body<'tcx> { impl<'tcx> Body<'tcx> {
@ -392,6 +400,7 @@ impl<'tcx> Body<'tcx> {
is_polymorphic: false, is_polymorphic: false,
injection_phase: None, injection_phase: None,
tainted_by_errors, tainted_by_errors,
function_coverage_info: None,
}; };
body.is_polymorphic = body.has_non_region_param(); body.is_polymorphic = body.has_non_region_param();
body body
@ -420,6 +429,7 @@ impl<'tcx> Body<'tcx> {
is_polymorphic: false, is_polymorphic: false,
injection_phase: None, injection_phase: None,
tainted_by_errors: None, tainted_by_errors: None,
function_coverage_info: None,
}; };
body.is_polymorphic = body.has_non_region_param(); body.is_polymorphic = body.has_non_region_param();
body body

29
compiler/rustc_middle/src/mir/pretty.rs
View File

@ -493,6 +493,27 @@ pub fn write_mir_intro<'tcx>(
// Add an empty line before the first block is printed. // Add an empty line before the first block is printed.
writeln!(w)?; writeln!(w)?;
if let Some(function_coverage_info) = &body.function_coverage_info {
write_function_coverage_info(function_coverage_info, w)?;
}
Ok(())
}
fn write_function_coverage_info(
function_coverage_info: &coverage::FunctionCoverageInfo,
w: &mut dyn io::Write,
) -> io::Result<()> {
let coverage::FunctionCoverageInfo { expressions, mappings, .. } = function_coverage_info;
for (id, expression) in expressions.iter_enumerated() {
writeln!(w, "{INDENT}coverage {id:?} => {expression:?};")?;
}
for coverage::Mapping { term, code_region } in mappings {
writeln!(w, "{INDENT}coverage {term:?} => {code_region:?};")?;
}
writeln!(w)?;
Ok(()) Ok(())
} }
@ -685,13 +706,7 @@ impl Debug for Statement<'_> {
AscribeUserType(box (ref place, ref c_ty), ref variance) => { AscribeUserType(box (ref place, ref c_ty), ref variance) => {
write!(fmt, "AscribeUserType({place:?}, {variance:?}, {c_ty:?})") write!(fmt, "AscribeUserType({place:?}, {variance:?}, {c_ty:?})")
} }
Coverage(box mir::Coverage { ref kind, ref code_regions }) => { Coverage(box mir::Coverage { ref kind }) => write!(fmt, "Coverage::{kind:?}"),
if code_regions.is_empty() {
write!(fmt, "Coverage::{kind:?}")
} else {
write!(fmt, "Coverage::{kind:?} for {code_regions:?}")
}
}
Intrinsic(box ref intrinsic) => write!(fmt, "{intrinsic}"), Intrinsic(box ref intrinsic) => write!(fmt, "{intrinsic}"),
ConstEvalCounter => write!(fmt, "ConstEvalCounter"), ConstEvalCounter => write!(fmt, "ConstEvalCounter"),
Nop => write!(fmt, "nop"), Nop => write!(fmt, "nop"),

24
compiler/rustc_middle/src/mir/query.rs
View File

@ -1,5 +1,6 @@
//! Values computed by queries that use MIR. //! Values computed by queries that use MIR.
use crate::mir;
use crate::ty::{self, OpaqueHiddenType, Ty, TyCtxt}; use crate::ty::{self, OpaqueHiddenType, Ty, TyCtxt};
use rustc_data_structures::fx::FxIndexMap; use rustc_data_structures::fx::FxIndexMap;
use rustc_data_structures::unord::UnordSet; use rustc_data_structures::unord::UnordSet;
@ -445,14 +446,19 @@ pub struct DestructuredConstant<'tcx> {
pub fields: &'tcx [(ConstValue<'tcx>, Ty<'tcx>)], pub fields: &'tcx [(ConstValue<'tcx>, Ty<'tcx>)],
} }
/// Coverage information summarized from a MIR if instrumented for source code coverage (see /// Summarizes coverage IDs inserted by the `InstrumentCoverage` MIR pass
/// compiler option `-Cinstrument-coverage`). This information is generated by the /// (for compiler option `-Cinstrument-coverage`), after MIR optimizations
/// `InstrumentCoverage` MIR pass and can be retrieved via the `coverageinfo` query. /// have had a chance to potentially remove some of them.
///
/// Used by the `coverage_ids_info` query.
#[derive(Clone, TyEncodable, TyDecodable, Debug, HashStable)] #[derive(Clone, TyEncodable, TyDecodable, Debug, HashStable)]
pub struct CoverageInfo { pub struct CoverageIdsInfo {
/// The total number of coverage region counters added to the MIR `Body`. /// Coverage codegen needs to know the highest counter ID that is ever
pub num_counters: u32, /// incremented within a function, so that it can set the `num-counters`
/// argument of the `llvm.instrprof.increment` intrinsic.
/// The total number of coverage region counter expressions added to the MIR `Body`. ///
pub num_expressions: u32, /// This may be less than the highest counter ID emitted by the
/// InstrumentCoverage MIR pass, if the highest-numbered counter increments
/// were removed by MIR optimizations.
pub max_counter_id: mir::coverage::CounterId,
} }

18
compiler/rustc_middle/src/mir/syntax.rs
View File

@ -5,7 +5,7 @@
use super::{BasicBlock, Const, Local, UserTypeProjection}; use super::{BasicBlock, Const, Local, UserTypeProjection};
use crate::mir::coverage::{CodeRegion, CoverageKind}; use crate::mir::coverage::CoverageKind;
use crate::traits::Reveal; use crate::traits::Reveal;
use crate::ty::adjustment::PointerCoercion; use crate::ty::adjustment::PointerCoercion;
use crate::ty::GenericArgsRef; use crate::ty::GenericArgsRef;
@ -361,11 +361,16 @@ pub enum StatementKind<'tcx> {
/// Disallowed after drop elaboration. /// Disallowed after drop elaboration.
AscribeUserType(Box<(Place<'tcx>, UserTypeProjection)>, ty::Variance), AscribeUserType(Box<(Place<'tcx>, UserTypeProjection)>, ty::Variance),
/// Marks the start of a "coverage region", injected with '-Cinstrument-coverage'. A /// Carries control-flow-sensitive information injected by `-Cinstrument-coverage`,
/// `Coverage` statement carries metadata about the coverage region, used to inject a coverage /// such as where to generate physical coverage-counter-increments during codegen.
/// map into the binary. If `Coverage::kind` is a `Counter`, the statement also generates ///
/// executable code, to increment a counter variable at runtime, each time the code region is /// Coverage statements are used in conjunction with the coverage mappings and other
/// executed. /// information stored in the function's
/// [`mir::Body::function_coverage_info`](crate::mir::Body::function_coverage_info).
/// (For inlined MIR, take care to look up the *original function's* coverage info.)
///
/// Interpreters and codegen backends that don't support coverage instrumentation
/// can usually treat this as a no-op.
Coverage(Box<Coverage>), Coverage(Box<Coverage>),
/// Denotes a call to an intrinsic that does not require an unwind path and always returns. /// Denotes a call to an intrinsic that does not require an unwind path and always returns.
@ -514,7 +519,6 @@ pub enum FakeReadCause {
#[derive(TypeFoldable, TypeVisitable)] #[derive(TypeFoldable, TypeVisitable)]
pub struct Coverage { pub struct Coverage {
pub kind: CoverageKind, pub kind: CoverageKind,
pub code_regions: Vec<CodeRegion>,
} }
#[derive(Clone, Debug, PartialEq, TyEncodable, TyDecodable, Hash, HashStable)] #[derive(Clone, Debug, PartialEq, TyEncodable, TyDecodable, Hash, HashStable)]

20
compiler/rustc_middle/src/query/mod.rs
View File

@ -573,24 +573,14 @@ rustc_queries! {
separate_provide_extern separate_provide_extern
} }
/// Returns coverage summary info for a function, after executing the `InstrumentCoverage` /// Summarizes coverage IDs inserted by the `InstrumentCoverage` MIR pass
/// MIR pass (assuming the -Cinstrument-coverage option is enabled). /// (for compiler option `-Cinstrument-coverage`), after MIR optimizations
query coverageinfo(key: ty::InstanceDef<'tcx>) -> &'tcx mir::CoverageInfo { /// have had a chance to potentially remove some of them.
desc { |tcx| "retrieving coverage info from MIR for `{}`", tcx.def_path_str(key.def_id()) } query coverage_ids_info(key: ty::InstanceDef<'tcx>) -> &'tcx mir::CoverageIdsInfo {
desc { |tcx| "retrieving coverage IDs info from MIR for `{}`", tcx.def_path_str(key.def_id()) }
arena_cache arena_cache
} }
/// Returns the `CodeRegions` for a function that has instrumented coverage, in case the
/// function was optimized out before codegen, and before being added to the Coverage Map.
query covered_code_regions(key: DefId) -> &'tcx Vec<&'tcx mir::coverage::CodeRegion> {
desc {
|tcx| "retrieving the covered `CodeRegion`s, if instrumented, for `{}`",
tcx.def_path_str(key)
}
arena_cache
cache_on_disk_if { key.is_local() }
}
/// The `DefId` is the `DefId` of the containing MIR body. Promoteds do not have their own /// The `DefId` is the `DefId` of the containing MIR body. Promoteds do not have their own
/// `DefId`. This function returns all promoteds in the specified body. The body references /// `DefId`. This function returns all promoteds in the specified body. The body references
/// promoteds by the `DefId` and the `mir::Promoted` index. This is necessary, because /// promoteds by the `DefId` and the `mir::Promoted` index. This is necessary, because

1
compiler/rustc_mir_build/src/build/custom/mod.rs
View File

@ -60,6 +60,7 @@ pub(super) fn build_custom_mir<'tcx>(
tainted_by_errors: None, tainted_by_errors: None,
injection_phase: None, injection_phase: None,
pass_count: 0, pass_count: 0,
function_coverage_info: None,
}; };
body.local_decls.push(LocalDecl::new(return_ty, return_ty_span)); body.local_decls.push(LocalDecl::new(return_ty, return_ty_span));

2
compiler/rustc_mir_transform/src/abort_unwinding_calls.rs
View File

@ -113,6 +113,6 @@ impl<'tcx> MirPass<'tcx> for AbortUnwindingCalls {
} }
// We may have invalidated some `cleanup` blocks so clean those up now. // We may have invalidated some `cleanup` blocks so clean those up now.
super::simplify::remove_dead_blocks(tcx, body); super::simplify::remove_dead_blocks(body);
} }
} }

87
compiler/rustc_mir_transform/src/coverage/counters.rs
View File

@ -19,7 +19,7 @@ const NESTED_INDENT: &str = " ";
#[derive(Clone)] #[derive(Clone)]
pub(super) enum BcbCounter { pub(super) enum BcbCounter {
Counter { id: CounterId }, Counter { id: CounterId },
Expression { id: ExpressionId, lhs: Operand, op: Op, rhs: Operand }, Expression { id: ExpressionId },
} }
impl BcbCounter { impl BcbCounter {
@ -27,10 +27,10 @@ impl BcbCounter {
matches!(self, Self::Expression { .. }) matches!(self, Self::Expression { .. })
} }
pub(super) fn as_operand(&self) -> Operand { pub(super) fn as_term(&self) -> CovTerm {
match *self { match *self {
BcbCounter::Counter { id, .. } => Operand::Counter(id), BcbCounter::Counter { id, .. } => CovTerm::Counter(id),
BcbCounter::Expression { id, .. } => Operand::Expression(id), BcbCounter::Expression { id, .. } => CovTerm::Expression(id),
} }
} }
} }
@ -39,17 +39,7 @@ impl Debug for BcbCounter {
fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result { fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
match self { match self {
Self::Counter { id, .. } => write!(fmt, "Counter({:?})", id.index()), Self::Counter { id, .. } => write!(fmt, "Counter({:?})", id.index()),
Self::Expression { id, lhs, op, rhs } => write!( Self::Expression { id } => write!(fmt, "Expression({:?})", id.index()),
fmt,
"Expression({:?}) = {:?} {} {:?}",
id.index(),
lhs,
match op {
Op::Add => "+",
Op::Subtract => "-",
},
rhs,
),
} }
} }
} }
@ -58,7 +48,6 @@ impl Debug for BcbCounter {
/// associated with nodes/edges in the BCB graph. /// associated with nodes/edges in the BCB graph.
pub(super) struct CoverageCounters { pub(super) struct CoverageCounters {
next_counter_id: CounterId, next_counter_id: CounterId,
next_expression_id: ExpressionId,
/// Coverage counters/expressions that are associated with individual BCBs. /// Coverage counters/expressions that are associated with individual BCBs.
bcb_counters: IndexVec<BasicCoverageBlock, Option<BcbCounter>>, bcb_counters: IndexVec<BasicCoverageBlock, Option<BcbCounter>>,
@ -69,10 +58,9 @@ pub(super) struct CoverageCounters {
/// Only used by debug assertions, to verify that BCBs with incoming edge /// Only used by debug assertions, to verify that BCBs with incoming edge
/// counters do not have their own physical counters (expressions are allowed). /// counters do not have their own physical counters (expressions are allowed).
bcb_has_incoming_edge_counters: BitSet<BasicCoverageBlock>, bcb_has_incoming_edge_counters: BitSet<BasicCoverageBlock>,
/// Expression nodes that are not directly associated with any particular /// Table of expression data, associating each expression ID with its
/// BCB/edge, but are needed as operands to more complex expressions. /// corresponding operator (+ or -) and its LHS/RHS operands.
/// These are always [`BcbCounter::Expression`]. expressions: IndexVec<ExpressionId, Expression>,
pub(super) intermediate_expressions: Vec<BcbCounter>,
} }
impl CoverageCounters { impl CoverageCounters {
@ -81,12 +69,10 @@ impl CoverageCounters {
Self { Self {
next_counter_id: CounterId::START, next_counter_id: CounterId::START,
next_expression_id: ExpressionId::START,
bcb_counters: IndexVec::from_elem_n(None, num_bcbs), bcb_counters: IndexVec::from_elem_n(None, num_bcbs),
bcb_edge_counters: FxHashMap::default(), bcb_edge_counters: FxHashMap::default(),
bcb_has_incoming_edge_counters: BitSet::new_empty(num_bcbs), bcb_has_incoming_edge_counters: BitSet::new_empty(num_bcbs),
intermediate_expressions: Vec::new(), expressions: IndexVec::new(),
} }
} }
@ -106,9 +92,9 @@ impl CoverageCounters {
BcbCounter::Counter { id } BcbCounter::Counter { id }
} }
fn make_expression(&mut self, lhs: Operand, op: Op, rhs: Operand) -> BcbCounter { fn make_expression(&mut self, lhs: CovTerm, op: Op, rhs: CovTerm) -> BcbCounter {
let id = self.next_expression(); let id = self.expressions.push(Expression { lhs, op, rhs });
BcbCounter::Expression { id, lhs, op, rhs } BcbCounter::Expression { id }
} }
/// Counter IDs start from one and go up. /// Counter IDs start from one and go up.
@ -118,19 +104,20 @@ impl CoverageCounters {
next next
} }
/// Expression IDs start from 0 and go up. pub(super) fn num_counters(&self) -> usize {
/// (Counter IDs and Expression IDs are distinguished by the `Operand` enum.) self.next_counter_id.as_usize()
fn next_expression(&mut self) -> ExpressionId { }
let next = self.next_expression_id;
self.next_expression_id = self.next_expression_id + 1; #[cfg(test)]
next pub(super) fn num_expressions(&self) -> usize {
self.expressions.len()
} }
fn set_bcb_counter( fn set_bcb_counter(
&mut self, &mut self,
bcb: BasicCoverageBlock, bcb: BasicCoverageBlock,
counter_kind: BcbCounter, counter_kind: BcbCounter,
) -> Result<Operand, Error> { ) -> Result<CovTerm, Error> {
debug_assert!( debug_assert!(
// If the BCB has an edge counter (to be injected into a new `BasicBlock`), it can also // If the BCB has an edge counter (to be injected into a new `BasicBlock`), it can also
// have an expression (to be injected into an existing `BasicBlock` represented by this // have an expression (to be injected into an existing `BasicBlock` represented by this
@ -138,14 +125,14 @@ impl CoverageCounters {
counter_kind.is_expression() || !self.bcb_has_incoming_edge_counters.contains(bcb), counter_kind.is_expression() || !self.bcb_has_incoming_edge_counters.contains(bcb),
"attempt to add a `Counter` to a BCB target with existing incoming edge counters" "attempt to add a `Counter` to a BCB target with existing incoming edge counters"
); );
let operand = counter_kind.as_operand(); let term = counter_kind.as_term();
if let Some(replaced) = self.bcb_counters[bcb].replace(counter_kind) { if let Some(replaced) = self.bcb_counters[bcb].replace(counter_kind) {
Error::from_string(format!( Error::from_string(format!(
"attempt to set a BasicCoverageBlock coverage counter more than once; \ "attempt to set a BasicCoverageBlock coverage counter more than once; \
{bcb:?} already had counter {replaced:?}", {bcb:?} already had counter {replaced:?}",
)) ))
} else { } else {
Ok(operand) Ok(term)
} }
} }
@ -154,7 +141,7 @@ impl CoverageCounters {
from_bcb: BasicCoverageBlock, from_bcb: BasicCoverageBlock,
to_bcb: BasicCoverageBlock, to_bcb: BasicCoverageBlock,
counter_kind: BcbCounter, counter_kind: BcbCounter,
) -> Result<Operand, Error> { ) -> Result<CovTerm, Error> {
if level_enabled!(tracing::Level::DEBUG) { if level_enabled!(tracing::Level::DEBUG) {
// If the BCB has an edge counter (to be injected into a new `BasicBlock`), it can also // If the BCB has an edge counter (to be injected into a new `BasicBlock`), it can also
// have an expression (to be injected into an existing `BasicBlock` represented by this // have an expression (to be injected into an existing `BasicBlock` represented by this
@ -167,14 +154,14 @@ impl CoverageCounters {
} }
} }
self.bcb_has_incoming_edge_counters.insert(to_bcb); self.bcb_has_incoming_edge_counters.insert(to_bcb);
let operand = counter_kind.as_operand(); let term = counter_kind.as_term();
if let Some(replaced) = self.bcb_edge_counters.insert((from_bcb, to_bcb), counter_kind) { if let Some(replaced) = self.bcb_edge_counters.insert((from_bcb, to_bcb), counter_kind) {
Error::from_string(format!( Error::from_string(format!(
"attempt to set an edge counter more than once; from_bcb: \ "attempt to set an edge counter more than once; from_bcb: \
{from_bcb:?} already had counter {replaced:?}", {from_bcb:?} already had counter {replaced:?}",
)) ))
} else { } else {
Ok(operand) Ok(term)
} }
} }
@ -199,6 +186,10 @@ impl CoverageCounters {
) -> impl Iterator<Item = ((BasicCoverageBlock, BasicCoverageBlock), BcbCounter)> + '_ { ) -> impl Iterator<Item = ((BasicCoverageBlock, BasicCoverageBlock), BcbCounter)> + '_ {
self.bcb_edge_counters.drain() self.bcb_edge_counters.drain()
} }
pub(super) fn take_expressions(&mut self) -> IndexVec<ExpressionId, Expression> {
std::mem::take(&mut self.expressions)
}
} }
/// Traverse the `CoverageGraph` and add either a `Counter` or `Expression` to every BCB, to be /// Traverse the `CoverageGraph` and add either a `Counter` or `Expression` to every BCB, to be
@ -276,7 +267,7 @@ impl<'a> MakeBcbCounters<'a> {
&mut self, &mut self,
traversal: &TraverseCoverageGraphWithLoops<'_>, traversal: &TraverseCoverageGraphWithLoops<'_>,
branching_bcb: BasicCoverageBlock, branching_bcb: BasicCoverageBlock,
branching_counter_operand: Operand, branching_counter_operand: CovTerm,
) -> Result<(), Error> { ) -> Result<(), Error> {
let branches = self.bcb_branches(branching_bcb); let branches = self.bcb_branches(branching_bcb);
debug!( debug!(
@ -324,8 +315,7 @@ impl<'a> MakeBcbCounters<'a> {
sumup_counter_operand, sumup_counter_operand,
); );
debug!(" [new intermediate expression: {:?}]", intermediate_expression); debug!(" [new intermediate expression: {:?}]", intermediate_expression);
let intermediate_expression_operand = intermediate_expression.as_operand(); let intermediate_expression_operand = intermediate_expression.as_term();
self.coverage_counters.intermediate_expressions.push(intermediate_expression);
some_sumup_counter_operand.replace(intermediate_expression_operand); some_sumup_counter_operand.replace(intermediate_expression_operand);
} }
} }
@ -356,7 +346,7 @@ impl<'a> MakeBcbCounters<'a> {
Ok(()) Ok(())
} }
fn get_or_make_counter_operand(&mut self, bcb: BasicCoverageBlock) -> Result<Operand, Error> { fn get_or_make_counter_operand(&mut self, bcb: BasicCoverageBlock) -> Result<CovTerm, Error> {
self.recursive_get_or_make_counter_operand(bcb, 1) self.recursive_get_or_make_counter_operand(bcb, 1)
} }
@ -364,7 +354,7 @@ impl<'a> MakeBcbCounters<'a> {
&mut self, &mut self,
bcb: BasicCoverageBlock, bcb: BasicCoverageBlock,
debug_indent_level: usize, debug_indent_level: usize,
) -> Result<Operand, Error> { ) -> Result<CovTerm, Error> {
// If the BCB already has a counter, return it. // If the BCB already has a counter, return it.
if let Some(counter_kind) = &self.coverage_counters.bcb_counters[bcb] { if let Some(counter_kind) = &self.coverage_counters.bcb_counters[bcb] {
debug!( debug!(
@ -373,7 +363,7 @@ impl<'a> MakeBcbCounters<'a> {
bcb, bcb,
counter_kind, counter_kind,
); );
return Ok(counter_kind.as_operand()); return Ok(counter_kind.as_term());
} }
// A BCB with only one incoming edge gets a simple `Counter` (via `make_counter()`). // A BCB with only one incoming edge gets a simple `Counter` (via `make_counter()`).
@ -437,8 +427,7 @@ impl<'a> MakeBcbCounters<'a> {
NESTED_INDENT.repeat(debug_indent_level), NESTED_INDENT.repeat(debug_indent_level),
intermediate_expression intermediate_expression
); );
let intermediate_expression_operand = intermediate_expression.as_operand(); let intermediate_expression_operand = intermediate_expression.as_term();
self.coverage_counters.intermediate_expressions.push(intermediate_expression);
some_sumup_edge_counter_operand.replace(intermediate_expression_operand); some_sumup_edge_counter_operand.replace(intermediate_expression_operand);
} }
} }
@ -460,7 +449,7 @@ impl<'a> MakeBcbCounters<'a> {
&mut self, &mut self,
from_bcb: BasicCoverageBlock, from_bcb: BasicCoverageBlock,
to_bcb: BasicCoverageBlock, to_bcb: BasicCoverageBlock,
) -> Result<Operand, Error> { ) -> Result<CovTerm, Error> {
self.recursive_get_or_make_edge_counter_operand(from_bcb, to_bcb, 1) self.recursive_get_or_make_edge_counter_operand(from_bcb, to_bcb, 1)
} }
@ -469,7 +458,7 @@ impl<'a> MakeBcbCounters<'a> {
from_bcb: BasicCoverageBlock, from_bcb: BasicCoverageBlock,
to_bcb: BasicCoverageBlock, to_bcb: BasicCoverageBlock,
debug_indent_level: usize, debug_indent_level: usize,
) -> Result<Operand, Error> { ) -> Result<CovTerm, Error> {
// If the source BCB has only one successor (assumed to be the given target), an edge // If the source BCB has only one successor (assumed to be the given target), an edge
// counter is unnecessary. Just get or make a counter for the source BCB. // counter is unnecessary. Just get or make a counter for the source BCB.
let successors = self.bcb_successors(from_bcb).iter(); let successors = self.bcb_successors(from_bcb).iter();
@ -488,7 +477,7 @@ impl<'a> MakeBcbCounters<'a> {
to_bcb, to_bcb,
counter_kind counter_kind
); );
return Ok(counter_kind.as_operand()); return Ok(counter_kind.as_term());
} }
// Make a new counter to count this edge. // Make a new counter to count this edge.

78
compiler/rustc_mir_transform/src/coverage/mod.rs
View File

@ -104,6 +104,7 @@ struct Instrumentor<'a, 'tcx> {
function_source_hash: u64, function_source_hash: u64,
basic_coverage_blocks: CoverageGraph, basic_coverage_blocks: CoverageGraph,
coverage_counters: CoverageCounters, coverage_counters: CoverageCounters,
mappings: Vec<Mapping>,
} }
impl<'a, 'tcx> Instrumentor<'a, 'tcx> { impl<'a, 'tcx> Instrumentor<'a, 'tcx> {
@ -144,6 +145,7 @@ impl<'a, 'tcx> Instrumentor<'a, 'tcx> {
function_source_hash, function_source_hash,
basic_coverage_blocks, basic_coverage_blocks,
coverage_counters, coverage_counters,
mappings: Vec::new(),
} }
} }
@ -165,9 +167,6 @@ impl<'a, 'tcx> Instrumentor<'a, 'tcx> {
// every coverage span has a `Counter` or `Expression` assigned to its `BasicCoverageBlock` // every coverage span has a `Counter` or `Expression` assigned to its `BasicCoverageBlock`
// and all `Expression` dependencies (operands) are also generated, for any other // and all `Expression` dependencies (operands) are also generated, for any other
// `BasicCoverageBlock`s not already associated with a coverage span. // `BasicCoverageBlock`s not already associated with a coverage span.
//
// Intermediate expressions (used to compute other `Expression` values), which have no
// direct association with any `BasicCoverageBlock`, are accumulated inside `coverage_counters`.
let bcb_has_coverage_spans = |bcb| coverage_spans.bcb_has_coverage_spans(bcb); let bcb_has_coverage_spans = |bcb| coverage_spans.bcb_has_coverage_spans(bcb);
let result = self let result = self
.coverage_counters .coverage_counters
@ -193,24 +192,18 @@ impl<'a, 'tcx> Instrumentor<'a, 'tcx> {
// are in fact counted, even though they don't directly contribute to counting // are in fact counted, even though they don't directly contribute to counting
// their own independent code region's coverage. // their own independent code region's coverage.
self.inject_indirect_counters(); self.inject_indirect_counters();
// Intermediate expressions will be injected as the final step, after generating
// debug output, if any.
////////////////////////////////////////////////////
}; };
if let Err(e) = result { if let Err(e) = result {
bug!("Error processing: {:?}: {:?}", self.mir_body.source.def_id(), e.message) bug!("Error processing: {:?}: {:?}", self.mir_body.source.def_id(), e.message)
}; };
//////////////////////////////////////////////////// self.mir_body.function_coverage_info = Some(Box::new(FunctionCoverageInfo {
// Finally, inject the intermediate expressions collected along the way. function_source_hash: self.function_source_hash,
for intermediate_expression in &self.coverage_counters.intermediate_expressions { num_counters: self.coverage_counters.num_counters(),
inject_intermediate_expression( expressions: self.coverage_counters.take_expressions(),
self.mir_body, mappings: std::mem::take(&mut self.mappings),
self.make_mir_coverage_kind(intermediate_expression), }));
);
}
} }
/// Injects a single [`StatementKind::Coverage`] for each BCB that has one /// Injects a single [`StatementKind::Coverage`] for each BCB that has one
@ -226,18 +219,16 @@ impl<'a, 'tcx> Instrumentor<'a, 'tcx> {
bug!("Every BasicCoverageBlock should have a Counter or Expression"); bug!("Every BasicCoverageBlock should have a Counter or Expression");
}); });
// Convert the coverage spans into a vector of code regions to be let term = counter_kind.as_term();
// associated with this BCB's coverage statement. self.mappings.extend(spans.iter().map(|&span| {
let code_regions = spans let code_region = make_code_region(source_map, file_name, span, body_span);
.iter() Mapping { code_region, term }
.map(|&span| make_code_region(source_map, file_name, span, body_span)) }));
.collect::<Vec<_>>();
inject_statement( inject_statement(
self.mir_body, self.mir_body,
self.make_mir_coverage_kind(&counter_kind), self.make_mir_coverage_kind(&counter_kind),
self.bcb_leader_bb(bcb), self.bcb_leader_bb(bcb),
code_regions,
); );
} }
} }
@ -295,13 +286,10 @@ impl<'a, 'tcx> Instrumentor<'a, 'tcx> {
self.mir_body, self.mir_body,
self.make_mir_coverage_kind(&counter_kind), self.make_mir_coverage_kind(&counter_kind),
inject_to_bb, inject_to_bb,
Vec::new(),
); );
} }
BcbCounter::Expression { .. } => inject_intermediate_expression( // Experessions with no associated spans don't need to inject a statement.
self.mir_body, BcbCounter::Expression { .. } => {}
self.make_mir_coverage_kind(&counter_kind),
),
} }
} }
} }
@ -323,12 +311,8 @@ impl<'a, 'tcx> Instrumentor<'a, 'tcx> {
fn make_mir_coverage_kind(&self, counter_kind: &BcbCounter) -> CoverageKind { fn make_mir_coverage_kind(&self, counter_kind: &BcbCounter) -> CoverageKind {
match *counter_kind { match *counter_kind {
BcbCounter::Counter { id } => { BcbCounter::Counter { id } => CoverageKind::CounterIncrement { id },
CoverageKind::Counter { function_source_hash: self.function_source_hash, id } BcbCounter::Expression { id } => CoverageKind::ExpressionUsed { id },
}
BcbCounter::Expression { id, lhs, op, rhs } => {
CoverageKind::Expression { id, lhs, op, rhs }
}
} }
} }
} }
@ -356,39 +340,17 @@ fn inject_edge_counter_basic_block(
new_bb new_bb
} }
fn inject_statement( fn inject_statement(mir_body: &mut mir::Body<'_>, counter_kind: CoverageKind, bb: BasicBlock) {
mir_body: &mut mir::Body<'_>, debug!(" injecting statement {counter_kind:?} for {bb:?}");
counter_kind: CoverageKind,
bb: BasicBlock,
code_regions: Vec<CodeRegion>,
) {
debug!(" injecting statement {counter_kind:?} for {bb:?} at code regions: {code_regions:?}");
let data = &mut mir_body[bb]; let data = &mut mir_body[bb];
let source_info = data.terminator().source_info; let source_info = data.terminator().source_info;
let statement = Statement { let statement = Statement {
source_info, source_info,
kind: StatementKind::Coverage(Box::new(Coverage { kind: counter_kind, code_regions })), kind: StatementKind::Coverage(Box::new(Coverage { kind: counter_kind })),
}; };
data.statements.insert(0, statement); data.statements.insert(0, statement);
} }
// Non-code expressions are injected into the coverage map, without generating executable code.
fn inject_intermediate_expression(mir_body: &mut mir::Body<'_>, expression: CoverageKind) {
debug_assert!(matches!(expression, CoverageKind::Expression { .. }));
debug!(" injecting non-code expression {:?}", expression);
let inject_in_bb = mir::START_BLOCK;
let data = &mut mir_body[inject_in_bb];
let source_info = data.terminator().source_info;
let statement = Statement {
source_info,
kind: StatementKind::Coverage(Box::new(Coverage {
kind: expression,
code_regions: Vec::new(),
})),
};
data.statements.push(statement);
}
/// Convert the Span into its file name, start line and column, and end line and column /// Convert the Span into its file name, start line and column, and end line and column
fn make_code_region( fn make_code_region(
source_map: &SourceMap, source_map: &SourceMap,

107
compiler/rustc_mir_transform/src/coverage/query.rs
View File

@ -2,100 +2,31 @@ use super::*;
use rustc_data_structures::captures::Captures; use rustc_data_structures::captures::Captures;
use rustc_middle::mir::coverage::*; use rustc_middle::mir::coverage::*;
use rustc_middle::mir::{self, Body, Coverage, CoverageInfo}; use rustc_middle::mir::{Body, Coverage, CoverageIdsInfo};
use rustc_middle::query::Providers; use rustc_middle::query::Providers;
use rustc_middle::ty::{self, TyCtxt}; use rustc_middle::ty::{self, TyCtxt};
use rustc_span::def_id::DefId;
/// A `query` provider for retrieving coverage information injected into MIR. /// A `query` provider for retrieving coverage information injected into MIR.
pub(crate) fn provide(providers: &mut Providers) { pub(crate) fn provide(providers: &mut Providers) {
providers.coverageinfo = |tcx, def_id| coverageinfo(tcx, def_id); providers.coverage_ids_info = |tcx, def_id| coverage_ids_info(tcx, def_id);
providers.covered_code_regions = |tcx, def_id| covered_code_regions(tcx, def_id);
} }
/// Coverage codegen needs to know the total number of counter IDs and expression IDs that have /// Query implementation for `coverage_ids_info`.
/// been used by a function's coverage mappings. These totals are used to create vectors to hold fn coverage_ids_info<'tcx>(
/// the relevant counter and expression data, and the maximum counter ID (+ 1) is also needed by tcx: TyCtxt<'tcx>,
/// the `llvm.instrprof.increment` intrinsic. instance_def: ty::InstanceDef<'tcx>,
/// ) -> CoverageIdsInfo {
/// MIR optimization may split and duplicate some BasicBlock sequences, or optimize out some code
/// including injected counters. (It is OK if some counters are optimized out, but those counters
/// are still included in the total `num_counters` or `num_expressions`.) Simply counting the
/// calls may not work; but computing the number of counters or expressions by adding `1` to the
/// highest ID (for a given instrumented function) is valid.
///
/// It's possible for a coverage expression to remain in MIR while one or both of its operands
/// have been optimized away. To avoid problems in codegen, we include those operands' IDs when
/// determining the maximum counter/expression ID, even if the underlying counter/expression is
/// no longer present.
struct CoverageVisitor {
max_counter_id: CounterId,
max_expression_id: ExpressionId,
}
impl CoverageVisitor {
/// Updates `max_counter_id` to the maximum encountered counter ID.
#[inline(always)]
fn update_max_counter_id(&mut self, counter_id: CounterId) {
self.max_counter_id = self.max_counter_id.max(counter_id);
}
/// Updates `max_expression_id` to the maximum encountered expression ID.
#[inline(always)]
fn update_max_expression_id(&mut self, expression_id: ExpressionId) {
self.max_expression_id = self.max_expression_id.max(expression_id);
}
fn update_from_expression_operand(&mut self, operand: Operand) {
match operand {
Operand::Counter(id) => self.update_max_counter_id(id),
Operand::Expression(id) => self.update_max_expression_id(id),
Operand::Zero => {}
}
}
fn visit_body(&mut self, body: &Body<'_>) {
for coverage in all_coverage_in_mir_body(body) {
self.visit_coverage(coverage);
}
}
fn visit_coverage(&mut self, coverage: &Coverage) {
match coverage.kind {
CoverageKind::Counter { id, .. } => self.update_max_counter_id(id),
CoverageKind::Expression { id, lhs, rhs, .. } => {
self.update_max_expression_id(id);
self.update_from_expression_operand(lhs);
self.update_from_expression_operand(rhs);
}
CoverageKind::Unreachable => {}
}
}
}
fn coverageinfo<'tcx>(tcx: TyCtxt<'tcx>, instance_def: ty::InstanceDef<'tcx>) -> CoverageInfo {
let mir_body = tcx.instance_mir(instance_def); let mir_body = tcx.instance_mir(instance_def);
let mut coverage_visitor = CoverageVisitor { let max_counter_id = all_coverage_in_mir_body(mir_body)
max_counter_id: CounterId::START, .filter_map(|coverage| match coverage.kind {
max_expression_id: ExpressionId::START, CoverageKind::CounterIncrement { id } => Some(id),
}; _ => None,
})
.max()
.unwrap_or(CounterId::START);
coverage_visitor.visit_body(mir_body); CoverageIdsInfo { max_counter_id }
// Add 1 to the highest IDs to get the total number of IDs.
CoverageInfo {
num_counters: (coverage_visitor.max_counter_id + 1).as_u32(),
num_expressions: (coverage_visitor.max_expression_id + 1).as_u32(),
}
}
fn covered_code_regions(tcx: TyCtxt<'_>, def_id: DefId) -> Vec<&CodeRegion> {
let body = mir_body(tcx, def_id);
all_coverage_in_mir_body(body)
// Coverage statements have a list of code regions (possibly empty).
.flat_map(|coverage| coverage.code_regions.as_slice())
.collect()
} }
fn all_coverage_in_mir_body<'a, 'tcx>( fn all_coverage_in_mir_body<'a, 'tcx>(
@ -115,11 +46,3 @@ fn is_inlined(body: &Body<'_>, statement: &Statement<'_>) -> bool {
let scope_data = &body.source_scopes[statement.source_info.scope]; let scope_data = &body.source_scopes[statement.source_info.scope];
scope_data.inlined.is_some() || scope_data.inlined_parent_scope.is_some() scope_data.inlined.is_some() || scope_data.inlined_parent_scope.is_some()
} }
/// This function ensures we obtain the correct MIR for the given item irrespective of
/// whether that means const mir or runtime mir. For `const fn` this opts for runtime
/// mir.
fn mir_body(tcx: TyCtxt<'_>, def_id: DefId) -> &mir::Body<'_> {
let def = ty::InstanceDef::Item(def_id);
tcx.instance_mir(def)
}

2
compiler/rustc_mir_transform/src/coverage/tests.rs
View File

@ -656,7 +656,7 @@ fn test_make_bcb_counters() {
coverage_counters coverage_counters
.make_bcb_counters(&mut basic_coverage_blocks, bcb_has_coverage_spans) .make_bcb_counters(&mut basic_coverage_blocks, bcb_has_coverage_spans)
.expect("should be Ok"); .expect("should be Ok");
assert_eq!(coverage_counters.intermediate_expressions.len(), 0); assert_eq!(coverage_counters.num_expressions(), 0);
let_bcb!(1); let_bcb!(1);
assert_eq!( assert_eq!(

2
compiler/rustc_mir_transform/src/dest_prop.rs
View File

@ -244,7 +244,7 @@ impl<'tcx> MirPass<'tcx> for DestinationPropagation {
if round_count != 0 { if round_count != 0 {
// Merging can introduce overlap between moved arguments and/or call destination in an // Merging can introduce overlap between moved arguments and/or call destination in an
// unreachable code, which validator considers to be ill-formed. // unreachable code, which validator considers to be ill-formed.
remove_dead_blocks(tcx, body); remove_dead_blocks(body);
} }
trace!(round_count); trace!(round_count);

4
compiler/rustc_mir_transform/src/generator.rs
View File

@ -1088,7 +1088,7 @@ fn create_generator_drop_shim<'tcx>(
// Make sure we remove dead blocks to remove // Make sure we remove dead blocks to remove
// unrelated code from the resume part of the function // unrelated code from the resume part of the function
simplify::remove_dead_blocks(tcx, &mut body); simplify::remove_dead_blocks(&mut body);
// Update the body's def to become the drop glue. // Update the body's def to become the drop glue.
// This needs to be updated before the AbortUnwindingCalls pass. // This needs to be updated before the AbortUnwindingCalls pass.
@ -1276,7 +1276,7 @@ fn create_generator_resume_function<'tcx>(
// Make sure we remove dead blocks to remove // Make sure we remove dead blocks to remove
// unrelated code from the drop part of the function // unrelated code from the drop part of the function
simplify::remove_dead_blocks(tcx, body); simplify::remove_dead_blocks(body);
pm::run_passes_no_validate(tcx, body, &[&abort_unwinding_calls::AbortUnwindingCalls], None); pm::run_passes_no_validate(tcx, body, &[&abort_unwinding_calls::AbortUnwindingCalls], None);

2
compiler/rustc_mir_transform/src/inline.rs
View File

@ -63,7 +63,7 @@ impl<'tcx> MirPass<'tcx> for Inline {
if inline(tcx, body) { if inline(tcx, body) {
debug!("running simplify cfg on {:?}", body.source); debug!("running simplify cfg on {:?}", body.source);
CfgSimplifier::new(body).simplify(); CfgSimplifier::new(body).simplify();
remove_dead_blocks(tcx, body); remove_dead_blocks(body);
deref_finder(tcx, body); deref_finder(tcx, body);
} }
} }

2
compiler/rustc_mir_transform/src/multiple_return_terminators.rs
View File

@ -38,6 +38,6 @@ impl<'tcx> MirPass<'tcx> for MultipleReturnTerminators {
} }
} }
simplify::remove_dead_blocks(tcx, body) simplify::remove_dead_blocks(body)
} }
} }

105
compiler/rustc_mir_transform/src/simplify.rs
View File

@ -28,10 +28,8 @@
//! return. //! return.
use crate::MirPass; use crate::MirPass;
use rustc_data_structures::fx::{FxHashSet, FxIndexSet}; use rustc_data_structures::fx::FxIndexSet;
use rustc_index::bit_set::BitSet;
use rustc_index::{Idx, IndexSlice, IndexVec}; use rustc_index::{Idx, IndexSlice, IndexVec};
use rustc_middle::mir::coverage::*;
use rustc_middle::mir::visit::{MutVisitor, MutatingUseContext, PlaceContext, Visitor}; use rustc_middle::mir::visit::{MutVisitor, MutatingUseContext, PlaceContext, Visitor};
use rustc_middle::mir::*; use rustc_middle::mir::*;
use rustc_middle::ty::TyCtxt; use rustc_middle::ty::TyCtxt;
@ -68,7 +66,7 @@ impl SimplifyCfg {
pub fn simplify_cfg<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) { pub fn simplify_cfg<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
CfgSimplifier::new(body).simplify(); CfgSimplifier::new(body).simplify();
remove_duplicate_unreachable_blocks(tcx, body); remove_duplicate_unreachable_blocks(tcx, body);
remove_dead_blocks(tcx, body); remove_dead_blocks(body);
// FIXME: Should probably be moved into some kind of pass manager // FIXME: Should probably be moved into some kind of pass manager
body.basic_blocks_mut().raw.shrink_to_fit(); body.basic_blocks_mut().raw.shrink_to_fit();
@ -337,7 +335,7 @@ pub fn remove_duplicate_unreachable_blocks<'tcx>(tcx: TyCtxt<'tcx>, body: &mut B
} }
} }
pub fn remove_dead_blocks<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) { pub fn remove_dead_blocks(body: &mut Body<'_>) {
let reachable = traversal::reachable_as_bitset(body); let reachable = traversal::reachable_as_bitset(body);
let num_blocks = body.basic_blocks.len(); let num_blocks = body.basic_blocks.len();
if num_blocks == reachable.count() { if num_blocks == reachable.count() {
@ -345,10 +343,6 @@ pub fn remove_dead_blocks<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
} }
let basic_blocks = body.basic_blocks.as_mut(); let basic_blocks = body.basic_blocks.as_mut();
let source_scopes = &body.source_scopes;
if tcx.sess.instrument_coverage() {
save_unreachable_coverage(basic_blocks, source_scopes, &reachable);
}
let mut replacements: Vec<_> = (0..num_blocks).map(BasicBlock::new).collect(); let mut replacements: Vec<_> = (0..num_blocks).map(BasicBlock::new).collect();
let mut orig_index = 0; let mut orig_index = 0;
@ -370,99 +364,6 @@ pub fn remove_dead_blocks<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
} }
} }
/// Some MIR transforms can determine at compile time that a sequences of
/// statements will never be executed, so they can be dropped from the MIR.
/// For example, an `if` or `else` block that is guaranteed to never be executed
/// because its condition can be evaluated at compile time, such as by const
/// evaluation: `if false { ... }`.
///
/// Those statements are bypassed by redirecting paths in the CFG around the
/// `dead blocks`; but with `-C instrument-coverage`, the dead blocks usually
/// include `Coverage` statements representing the Rust source code regions to
/// be counted at runtime. Without these `Coverage` statements, the regions are
/// lost, and the Rust source code will show no coverage information.
///
/// What we want to show in a coverage report is the dead code with coverage
/// counts of `0`. To do this, we need to save the code regions, by injecting
/// `Unreachable` coverage statements. These are non-executable statements whose
/// code regions are still recorded in the coverage map, representing regions
/// with `0` executions.
///
/// If there are no live `Counter` `Coverage` statements remaining, we remove
/// `Coverage` statements along with the dead blocks. Since at least one
/// counter per function is required by LLVM (and necessary, to add the
/// `function_hash` to the counter's call to the LLVM intrinsic
/// `instrprof.increment()`).
///
/// The `generator::StateTransform` MIR pass and MIR inlining can create
/// atypical conditions, where all live `Counter`s are dropped from the MIR.
///
/// With MIR inlining we can have coverage counters belonging to different
/// instances in a single body, so the strategy described above is applied to
/// coverage counters from each instance individually.
fn save_unreachable_coverage(
basic_blocks: &mut IndexSlice<BasicBlock, BasicBlockData<'_>>,
source_scopes: &IndexSlice<SourceScope, SourceScopeData<'_>>,
reachable: &BitSet<BasicBlock>,
) {
// Identify instances that still have some live coverage counters left.
let mut live = FxHashSet::default();
for bb in reachable.iter() {
let basic_block = &basic_blocks[bb];
for statement in &basic_block.statements {
let StatementKind::Coverage(coverage) = &statement.kind else { continue };
let CoverageKind::Counter { .. } = coverage.kind else { continue };
let instance = statement.source_info.scope.inlined_instance(source_scopes);
live.insert(instance);
}
}
for bb in reachable.iter() {
let block = &mut basic_blocks[bb];
for statement in &mut block.statements {
let StatementKind::Coverage(_) = &statement.kind else { continue };
let instance = statement.source_info.scope.inlined_instance(source_scopes);
if !live.contains(&instance) {
statement.make_nop();
}
}
}
if live.is_empty() {
return;
}
// Retain coverage for instances that still have some live counters left.
let mut retained_coverage = Vec::new();
for dead_block in basic_blocks.indices() {
if reachable.contains(dead_block) {
continue;
}
let dead_block = &basic_blocks[dead_block];
for statement in &dead_block.statements {
let StatementKind::Coverage(coverage) = &statement.kind else { continue };
if coverage.code_regions.is_empty() {
continue;
};
let instance = statement.source_info.scope.inlined_instance(source_scopes);
if live.contains(&instance) {
retained_coverage.push((statement.source_info, coverage.code_regions.clone()));
}
}
}
let start_block = &mut basic_blocks[START_BLOCK];
start_block.statements.extend(retained_coverage.into_iter().map(
|(source_info, code_regions)| Statement {
source_info,
kind: StatementKind::Coverage(Box::new(Coverage {
kind: CoverageKind::Unreachable,
code_regions,
})),
},
));
}
pub enum SimplifyLocals { pub enum SimplifyLocals {
BeforeConstProp, BeforeConstProp,
Final, Final,

2
compiler/rustc_mir_transform/src/unreachable_prop.rs
View File

@ -65,7 +65,7 @@ impl MirPass<'_> for UnreachablePropagation {
} }
if replaced { if replaced {
simplify::remove_dead_blocks(tcx, body); simplify::remove_dead_blocks(body);
} }
} }
} }

5
tests/coverage-map/status-quo/issue-84561.cov-map
View File

@ -1,11 +1,10 @@
Function name: <issue_84561::Foo as core::cmp::PartialEq>::eq 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] Raw bytes (9): 0x[01, 01, 00, 01, 01, 04, 0a, 00, 13]
Number of files: 1 Number of files: 1
- file 0 => global file 1 - file 0 => global file 1
Number of expressions: 0 Number of expressions: 0
Number of file 0 mappings: 2 Number of file 0 mappings: 1
- Code(Counter(0)) at (prev + 4, 10) to (start + 0, 19) - 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 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] 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]

29
tests/coverage-map/status-quo/try_error_result.cov-map
View File

@ -1,62 +1,45 @@
Function name: <try_error_result::Thing1>::get_thing_2 Function name: <try_error_result::Thing1>::get_thing_2
Raw bytes (63): 0x[01, 01, 02, 01, 05, 05, 02, 0b, 01, 28, 05, 01, 18, 05, 02, 0d, 00, 14, 00, 00, 0d, 00, 14, 00, 00, 0d, 00, 14, 00, 00, 0d, 00, 14, 00, 00, 0d, 00, 14, 00, 00, 0d, 00, 14, 02, 02, 0d, 00, 1a, 00, 00, 0d, 00, 1a, 00, 00, 0d, 00, 1a, 07, 02, 05, 00, 06] 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 Number of files: 1
- file 0 => global file 1 - file 0 => global file 1
Number of expressions: 2 Number of expressions: 2
- expression 0 operands: lhs = Counter(0), rhs = Counter(1) - expression 0 operands: lhs = Counter(0), rhs = Counter(1)
- expression 1 operands: lhs = Counter(1), rhs = Expression(0, Sub) - expression 1 operands: lhs = Counter(1), rhs = Expression(0, Sub)
Number of file 0 mappings: 11 Number of file 0 mappings: 4
- Code(Counter(0)) at (prev + 40, 5) to (start + 1, 24) - Code(Counter(0)) at (prev + 40, 5) to (start + 1, 24)
- Code(Counter(1)) at (prev + 2, 13) to (start + 0, 20) - Code(Counter(1)) at (prev + 2, 13) to (start + 0, 20)
- Code(Zero) at (prev + 0, 13) to (start + 0, 20)
- Code(Zero) at (prev + 0, 13) to (start + 0, 20)
- Code(Zero) at (prev + 0, 13) to (start + 0, 20)
- Code(Zero) at (prev + 0, 13) to (start + 0, 20)
- Code(Zero) at (prev + 0, 13) to (start + 0, 20)
- Code(Expression(0, Sub)) at (prev + 2, 13) to (start + 0, 26) - Code(Expression(0, Sub)) at (prev + 2, 13) to (start + 0, 26)
= (c0 - c1) = (c0 - c1)
- Code(Zero) at (prev + 0, 13) to (start + 0, 26)
- Code(Zero) at (prev + 0, 13) to (start + 0, 26)
- Code(Expression(1, Add)) at (prev + 2, 5) to (start + 0, 6) - Code(Expression(1, Add)) at (prev + 2, 5) to (start + 0, 6)
= (c1 + (c0 - c1)) = (c1 + (c0 - c1))
Function name: <try_error_result::Thing2>::call Function name: <try_error_result::Thing2>::call
Raw bytes (63): 0x[01, 01, 02, 01, 05, 05, 02, 0b, 01, 33, 05, 01, 18, 05, 02, 0d, 00, 14, 00, 00, 0d, 00, 14, 00, 00, 0d, 00, 14, 00, 00, 0d, 00, 14, 00, 00, 0d, 00, 14, 02, 02, 0d, 00, 13, 00, 00, 0d, 00, 13, 00, 00, 0d, 00, 13, 00, 00, 0d, 00, 13, 07, 02, 05, 00, 06] 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 Number of files: 1
- file 0 => global file 1 - file 0 => global file 1
Number of expressions: 2 Number of expressions: 2
- expression 0 operands: lhs = Counter(0), rhs = Counter(1) - expression 0 operands: lhs = Counter(0), rhs = Counter(1)
- expression 1 operands: lhs = Counter(1), rhs = Expression(0, Sub) - expression 1 operands: lhs = Counter(1), rhs = Expression(0, Sub)
Number of file 0 mappings: 11 Number of file 0 mappings: 4
- Code(Counter(0)) at (prev + 51, 5) to (start + 1, 24) - Code(Counter(0)) at (prev + 51, 5) to (start + 1, 24)
- Code(Counter(1)) at (prev + 2, 13) to (start + 0, 20) - Code(Counter(1)) at (prev + 2, 13) to (start + 0, 20)
- Code(Zero) at (prev + 0, 13) to (start + 0, 20)
- Code(Zero) at (prev + 0, 13) to (start + 0, 20)
- Code(Zero) at (prev + 0, 13) to (start + 0, 20)
- Code(Zero) at (prev + 0, 13) to (start + 0, 20)
- Code(Expression(0, Sub)) at (prev + 2, 13) to (start + 0, 19) - Code(Expression(0, Sub)) at (prev + 2, 13) to (start + 0, 19)
= (c0 - c1) = (c0 - c1)
- Code(Zero) at (prev + 0, 13) to (start + 0, 19)
- Code(Zero) at (prev + 0, 13) to (start + 0, 19)
- Code(Zero) at (prev + 0, 13) to (start + 0, 19)
- Code(Expression(1, Add)) at (prev + 2, 5) to (start + 0, 6) - Code(Expression(1, Add)) at (prev + 2, 5) to (start + 0, 6)
= (c1 + (c0 - c1)) = (c1 + (c0 - c1))
Function name: try_error_result::call Function name: try_error_result::call
Raw bytes (43): 0x[01, 01, 02, 01, 05, 05, 02, 07, 01, 04, 01, 01, 14, 05, 02, 09, 00, 10, 00, 00, 09, 00, 10, 00, 00, 09, 00, 10, 02, 02, 09, 00, 0f, 00, 00, 09, 00, 0f, 07, 02, 01, 00, 02] 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 Number of files: 1
- file 0 => global file 1 - file 0 => global file 1
Number of expressions: 2 Number of expressions: 2
- expression 0 operands: lhs = Counter(0), rhs = Counter(1) - expression 0 operands: lhs = Counter(0), rhs = Counter(1)
- expression 1 operands: lhs = Counter(1), rhs = Expression(0, Sub) - expression 1 operands: lhs = Counter(1), rhs = Expression(0, Sub)
Number of file 0 mappings: 7 Number of file 0 mappings: 4
- Code(Counter(0)) at (prev + 4, 1) to (start + 1, 20) - Code(Counter(0)) at (prev + 4, 1) to (start + 1, 20)
- Code(Counter(1)) at (prev + 2, 9) to (start + 0, 16) - Code(Counter(1)) at (prev + 2, 9) to (start + 0, 16)
- Code(Zero) at (prev + 0, 9) to (start + 0, 16)
- Code(Zero) at (prev + 0, 9) to (start + 0, 16)
- Code(Expression(0, Sub)) at (prev + 2, 9) to (start + 0, 15) - Code(Expression(0, Sub)) at (prev + 2, 9) to (start + 0, 15)
= (c0 - c1) = (c0 - c1)
- Code(Zero) at (prev + 0, 9) to (start + 0, 15)
- Code(Expression(1, Add)) at (prev + 2, 1) to (start + 0, 2) - Code(Expression(1, Add)) at (prev + 2, 1) to (start + 0, 2)
= (c1 + (c0 - c1)) = (c1 + (c0 - c1))

4
tests/mir-opt/instrument_coverage.bar.InstrumentCoverage.diff
View File

@ -4,8 +4,10 @@
fn bar() -> bool { fn bar() -> bool {
let mut _0: bool; let mut _0: bool;
+ coverage Counter(0) => /the/src/instrument_coverage.rs:20:1 - 22:2;
+
bb0: { bb0: {
+ Coverage::Counter(0) for [/the/src/instrument_coverage.rs:20:1 - 22:2]; + Coverage::CounterIncrement(0);
_0 = const true; _0 = const true;
return; return;
} }

16
tests/mir-opt/instrument_coverage.main.InstrumentCoverage.diff
View File

@ -7,13 +7,21 @@
let mut _2: bool; let mut _2: bool;
let mut _3: !; let mut _3: !;
+ coverage ExpressionId(0) => Expression { lhs: Counter(0), op: Add, rhs: Counter(1) };
+ coverage ExpressionId(1) => Expression { lhs: Expression(0), op: Subtract, rhs: Counter(1) };
+ coverage Counter(0) => /the/src/instrument_coverage.rs:11:1 - 11:11;
+ coverage Expression(0) => /the/src/instrument_coverage.rs:12:5 - 13:17;
+ coverage Expression(1) => /the/src/instrument_coverage.rs:14:13 - 14:18;
+ coverage Expression(1) => /the/src/instrument_coverage.rs:17:1 - 17:2;
+ coverage Counter(1) => /the/src/instrument_coverage.rs:15:10 - 15:11;
+
bb0: { bb0: {
+ Coverage::Counter(0) for [/the/src/instrument_coverage.rs:11:1 - 11:11]; + Coverage::CounterIncrement(0);
goto -> bb1; goto -> bb1;
} }
bb1: { bb1: {
+ Coverage::Expression(0) = Counter(0) + Counter(1) for [/the/src/instrument_coverage.rs:12:5 - 13:17]; + Coverage::ExpressionUsed(0);
falseUnwind -> [real: bb2, unwind: bb6]; falseUnwind -> [real: bb2, unwind: bb6];
} }
@ -27,14 +35,14 @@
} }
bb4: { bb4: {
+ Coverage::Expression(1) = Expression(0) - Counter(1) for [/the/src/instrument_coverage.rs:14:13 - 14:18, /the/src/instrument_coverage.rs:17:1 - 17:2]; + Coverage::ExpressionUsed(1);
_0 = const (); _0 = const ();
StorageDead(_2); StorageDead(_2);
return; return;
} }
bb5: { bb5: {
+ Coverage::Counter(1) for [/the/src/instrument_coverage.rs:15:10 - 15:11]; + Coverage::CounterIncrement(1);
_1 = const (); _1 = const ();
StorageDead(_2); StorageDead(_2);
goto -> bb1; goto -> bb1;