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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-30 03:57:31 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-30 03:57:31 +0000 |
commit | dc0db358abe19481e475e10c32149b53370f1a1c (patch) | |
tree | ab8ce99c4b255ce46f99ef402c27916055b899ee /compiler/rustc_codegen_ssa/src/coverageinfo/map.rs | |
parent | Releasing progress-linux version 1.71.1+dfsg1-2~progress7.99u1. (diff) | |
download | rustc-dc0db358abe19481e475e10c32149b53370f1a1c.tar.xz rustc-dc0db358abe19481e475e10c32149b53370f1a1c.zip |
Merging upstream version 1.72.1+dfsg1.
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'compiler/rustc_codegen_ssa/src/coverageinfo/map.rs')
-rw-r--r-- | compiler/rustc_codegen_ssa/src/coverageinfo/map.rs | 347 |
1 files changed, 0 insertions, 347 deletions
diff --git a/compiler/rustc_codegen_ssa/src/coverageinfo/map.rs b/compiler/rustc_codegen_ssa/src/coverageinfo/map.rs deleted file mode 100644 index e4da3b8de..000000000 --- a/compiler/rustc_codegen_ssa/src/coverageinfo/map.rs +++ /dev/null @@ -1,347 +0,0 @@ -pub use super::ffi::*; - -use rustc_index::{IndexSlice, IndexVec}; -use rustc_middle::mir::coverage::{ - CodeRegion, CounterValueReference, ExpressionOperandId, InjectedExpressionId, - InjectedExpressionIndex, MappedExpressionIndex, Op, -}; -use rustc_middle::ty::Instance; -use rustc_middle::ty::TyCtxt; - -#[derive(Clone, Debug, PartialEq)] -pub struct Expression { - lhs: ExpressionOperandId, - op: Op, - rhs: ExpressionOperandId, - region: Option<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. Counters and counter expressions have non-overlapping `id`s because they -/// can both be operands in an expression. 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)] -pub struct FunctionCoverage<'tcx> { - instance: Instance<'tcx>, - source_hash: u64, - is_used: bool, - counters: IndexVec<CounterValueReference, Option<CodeRegion>>, - expressions: IndexVec<InjectedExpressionIndex, Option<Expression>>, - unreachable_regions: Vec<CodeRegion>, -} - -impl<'tcx> FunctionCoverage<'tcx> { - /// Creates a new set of coverage data for a used (called) function. - pub fn new(tcx: TyCtxt<'tcx>, instance: Instance<'tcx>) -> Self { - Self::create(tcx, instance, true) - } - - /// Creates a new set of coverage data for an unused (never called) function. - pub fn unused(tcx: TyCtxt<'tcx>, instance: Instance<'tcx>) -> Self { - Self::create(tcx, instance, false) - } - - fn create(tcx: TyCtxt<'tcx>, instance: Instance<'tcx>, is_used: bool) -> Self { - let coverageinfo = tcx.coverageinfo(instance.def); - debug!( - "FunctionCoverage::create(instance={:?}) has coverageinfo={:?}. is_used={}", - instance, coverageinfo, is_used - ); - Self { - instance, - source_hash: 0, // will be set with the first `add_counter()` - is_used, - counters: IndexVec::from_elem_n(None, coverageinfo.num_counters as usize), - expressions: IndexVec::from_elem_n(None, coverageinfo.num_expressions as usize), - unreachable_regions: Vec::new(), - } - } - - /// Returns true for a used (called) function, and false for an unused function. - pub fn is_used(&self) -> bool { - self.is_used - } - - /// Sets the function source hash value. If called multiple times for the same function, all - /// 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 a code region to be counted by an injected counter intrinsic. - pub fn add_counter(&mut self, id: CounterValueReference, region: CodeRegion) { - if let Some(previous_region) = self.counters[id].replace(region.clone()) { - assert_eq!(previous_region, region, "add_counter: code region for id changed"); - } - } - - /// Both counters and "counter expressions" (or simply, "expressions") can be operands in other - /// expressions. Expression IDs start from `u32::MAX` and go down, so the range of expression - /// IDs will not overlap with the range of counter IDs. Counters and expressions can be added in - /// any order, and expressions can still be assigned contiguous (though descending) IDs, without - /// knowing what the last counter ID will be. - /// - /// When storing the expression data in the `expressions` vector in the `FunctionCoverage` - /// struct, its vector index is computed, from the given expression ID, by subtracting from - /// `u32::MAX`. - /// - /// Since the expression operands (`lhs` and `rhs`) can reference either counters or - /// expressions, an operand that references an expression also uses its original ID, descending - /// from `u32::MAX`. Theses operands are translated only during code generation, after all - /// counters and expressions have been added. - pub fn add_counter_expression( - &mut self, - expression_id: InjectedExpressionId, - lhs: ExpressionOperandId, - op: Op, - rhs: ExpressionOperandId, - region: Option<CodeRegion>, - ) { - debug!( - "add_counter_expression({:?}, lhs={:?}, op={:?}, rhs={:?} at {:?}", - expression_id, lhs, op, rhs, region - ); - let expression_index = self.expression_index(u32::from(expression_id)); - debug_assert!( - expression_index.as_usize() < self.expressions.len(), - "expression_index {} is out of range for expressions.len() = {} - for {:?}", - expression_index.as_usize(), - self.expressions.len(), - self, - ); - if let Some(previous_expression) = self.expressions[expression_index].replace(Expression { - lhs, - op, - rhs, - region: region.clone(), - }) { - assert_eq!( - previous_expression, - Expression { lhs, op, rhs, region }, - "add_counter_expression: expression for id changed" - ); - } - } - - /// Add a region that will be marked as "unreachable", with a constant "zero counter". - pub fn add_unreachable_region(&mut self, region: CodeRegion) { - self.unreachable_regions.push(region) - } - - /// 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. - pub fn source_hash(&self) -> u64 { - self.source_hash - } - - /// Generate an array of CounterExpressions, and an iterator over all `Counter`s and their - /// associated `Regions` (from which the LLVM-specific `CoverageMapGenerator` will create - /// `CounterMappingRegion`s. - pub fn get_expressions_and_counter_regions( - &self, - ) -> (Vec<CounterExpression>, impl Iterator<Item = (Counter, &CodeRegion)>) { - assert!( - self.source_hash != 0 || !self.is_used, - "No counters provided the source_hash for used function: {:?}", - self.instance - ); - - let counter_regions = self.counter_regions(); - let (counter_expressions, expression_regions) = self.expressions_with_regions(); - let unreachable_regions = self.unreachable_regions(); - - let counter_regions = - counter_regions.chain(expression_regions.into_iter().chain(unreachable_regions)); - (counter_expressions, counter_regions) - } - - fn counter_regions(&self) -> impl Iterator<Item = (Counter, &CodeRegion)> { - self.counters.iter_enumerated().filter_map(|(index, entry)| { - // Option::map() will return None to filter out missing counters. This may happen - // if, for example, a MIR-instrumented counter is removed during an optimization. - entry.as_ref().map(|region| (Counter::counter_value_reference(index), region)) - }) - } - - fn expressions_with_regions( - &self, - ) -> (Vec<CounterExpression>, impl Iterator<Item = (Counter, &CodeRegion)>) { - let mut counter_expressions = Vec::with_capacity(self.expressions.len()); - let mut expression_regions = Vec::with_capacity(self.expressions.len()); - let mut new_indexes = IndexVec::from_elem_n(None, self.expressions.len()); - - // This closure converts any `Expression` operand (`lhs` or `rhs` of the `Op::Add` or - // `Op::Subtract` operation) into its native `llvm::coverage::Counter::CounterKind` type - // and value. Operand ID value `0` maps to `CounterKind::Zero`; values in the known range - // of injected LLVM counters map to `CounterKind::CounterValueReference` (and the value - // matches the injected counter index); and any other value is converted into a - // `CounterKind::Expression` with the expression's `new_index`. - // - // Expressions will be returned from this function in a sequential vector (array) of - // `CounterExpression`, so the expression IDs must be mapped from their original, - // potentially sparse set of indexes, originally in reverse order from `u32::MAX`. - // - // An `Expression` as an operand will have already been encountered as an `Expression` with - // operands, so its new_index will already have been generated (as a 1-up index value). - // (If an `Expression` as an operand does not have a corresponding new_index, it was - // probably optimized out, after the expression was injected into the MIR, so it will - // get a `CounterKind::Zero` instead.) - // - // In other words, an `Expression`s at any given index can include other expressions as - // operands, but expression operands can only come from the subset of expressions having - // `expression_index`s lower than the referencing `Expression`. Therefore, it is - // reasonable to look up the new index of an expression operand while the `new_indexes` - // vector is only complete up to the current `ExpressionIndex`. - let id_to_counter = |new_indexes: &IndexSlice< - InjectedExpressionIndex, - Option<MappedExpressionIndex>, - >, - id: ExpressionOperandId| { - if id == ExpressionOperandId::ZERO { - Some(Counter::zero()) - } else if id.index() < self.counters.len() { - debug_assert!( - id.index() > 0, - "ExpressionOperandId indexes for counters are 1-based, but this id={}", - id.index() - ); - // Note: Some codegen-injected Counters may be only referenced by `Expression`s, - // and may not have their own `CodeRegion`s, - let index = CounterValueReference::from(id.index()); - // Note, the conversion to LLVM `Counter` adjusts the index to be zero-based. - Some(Counter::counter_value_reference(index)) - } else { - let index = self.expression_index(u32::from(id)); - self.expressions - .get(index) - .expect("expression id is out of range") - .as_ref() - // If an expression was optimized out, assume it would have produced a count - // of zero. This ensures that expressions dependent on optimized-out - // expressions are still valid. - .map_or(Some(Counter::zero()), |_| new_indexes[index].map(Counter::expression)) - } - }; - - for (original_index, expression) in - self.expressions.iter_enumerated().filter_map(|(original_index, entry)| { - // Option::map() will return None to filter out missing expressions. This may happen - // if, for example, a MIR-instrumented expression is removed during an optimization. - entry.as_ref().map(|expression| (original_index, expression)) - }) - { - let optional_region = &expression.region; - let Expression { lhs, op, rhs, .. } = *expression; - - if let Some(Some((lhs_counter, mut rhs_counter))) = id_to_counter(&new_indexes, lhs) - .map(|lhs_counter| { - id_to_counter(&new_indexes, rhs).map(|rhs_counter| (lhs_counter, rhs_counter)) - }) - { - if lhs_counter.is_zero() && op.is_subtract() { - // The left side of a subtraction was probably optimized out. As an example, - // a branch condition might be evaluated as a constant expression, and the - // branch could be removed, dropping unused counters in the process. - // - // Since counters are unsigned, we must assume the result of the expression - // can be no more and no less than zero. An expression known to evaluate to zero - // does not need to be added to the coverage map. - // - // Coverage test `loops_branches.rs` includes multiple variations of branches - // based on constant conditional (literal `true` or `false`), and demonstrates - // that the expected counts are still correct. - debug!( - "Expression subtracts from zero (assume unreachable): \ - original_index={:?}, lhs={:?}, op={:?}, rhs={:?}, region={:?}", - original_index, lhs, op, rhs, optional_region, - ); - rhs_counter = Counter::zero(); - } - debug_assert!( - lhs_counter.is_zero() - // Note: with `as usize` the ID _could_ overflow/wrap if `usize = u16` - || ((lhs_counter.zero_based_id() as usize) - <= usize::max(self.counters.len(), self.expressions.len())), - "lhs id={} > both counters.len()={} and expressions.len()={} - ({:?} {:?} {:?})", - lhs_counter.zero_based_id(), - self.counters.len(), - self.expressions.len(), - lhs_counter, - op, - rhs_counter, - ); - - debug_assert!( - rhs_counter.is_zero() - // Note: with `as usize` the ID _could_ overflow/wrap if `usize = u16` - || ((rhs_counter.zero_based_id() as usize) - <= usize::max(self.counters.len(), self.expressions.len())), - "rhs id={} > both counters.len()={} and expressions.len()={} - ({:?} {:?} {:?})", - rhs_counter.zero_based_id(), - self.counters.len(), - self.expressions.len(), - lhs_counter, - op, - rhs_counter, - ); - - // Both operands exist. `Expression` operands exist in `self.expressions` and have - // been assigned a `new_index`. - let mapped_expression_index = - MappedExpressionIndex::from(counter_expressions.len()); - let expression = CounterExpression::new( - lhs_counter, - match op { - Op::Add => ExprKind::Add, - Op::Subtract => ExprKind::Subtract, - }, - rhs_counter, - ); - debug!( - "Adding expression {:?} = {:?}, region: {:?}", - mapped_expression_index, expression, optional_region - ); - counter_expressions.push(expression); - new_indexes[original_index] = Some(mapped_expression_index); - if let Some(region) = optional_region { - expression_regions.push((Counter::expression(mapped_expression_index), region)); - } - } else { - bug!( - "expression has one or more missing operands \ - original_index={:?}, lhs={:?}, op={:?}, rhs={:?}, region={:?}", - original_index, - lhs, - op, - rhs, - optional_region, - ); - } - } - (counter_expressions, expression_regions.into_iter()) - } - - fn unreachable_regions(&self) -> impl Iterator<Item = (Counter, &CodeRegion)> { - self.unreachable_regions.iter().map(|region| (Counter::zero(), region)) - } - - fn expression_index(&self, id_descending_from_max: u32) -> InjectedExpressionIndex { - debug_assert!(id_descending_from_max >= self.counters.len() as u32); - InjectedExpressionIndex::from(u32::MAX - id_descending_from_max) - } -} |