diff options
Diffstat (limited to 'compiler/rustc_codegen_llvm/src')
| -rw-r--r-- | compiler/rustc_codegen_llvm/src/coverageinfo/ffi.rs | 11 | ||||
| -rw-r--r-- | compiler/rustc_codegen_llvm/src/coverageinfo/map_data.rs | 105 | ||||
| -rw-r--r-- | compiler/rustc_codegen_llvm/src/coverageinfo/mod.rs | 4 |
3 files changed, 42 insertions, 78 deletions
diff --git a/compiler/rustc_codegen_llvm/src/coverageinfo/ffi.rs b/compiler/rustc_codegen_llvm/src/coverageinfo/ffi.rs index 194ed7d661d..7ad2d03a5ed 100644 --- a/compiler/rustc_codegen_llvm/src/coverageinfo/ffi.rs +++ b/compiler/rustc_codegen_llvm/src/coverageinfo/ffi.rs @@ -73,17 +73,6 @@ pub struct CounterExpression { 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`. /// /// Must match the layout of `LLVMRustCounterMappingRegionKind`. diff --git a/compiler/rustc_codegen_llvm/src/coverageinfo/map_data.rs b/compiler/rustc_codegen_llvm/src/coverageinfo/map_data.rs index e6b39c71453..84319b4ba2d 100644 --- a/compiler/rustc_codegen_llvm/src/coverageinfo/map_data.rs +++ b/compiler/rustc_codegen_llvm/src/coverageinfo/map_data.rs @@ -2,19 +2,11 @@ use crate::coverageinfo::ffi::{Counter, CounterExpression, ExprKind}; use rustc_data_structures::fx::FxIndexSet; use rustc_index::bit_set::BitSet; -use rustc_index::IndexVec; use rustc_middle::mir::coverage::{ - CodeRegion, CounterId, CovTerm, ExpressionId, FunctionCoverageInfo, Mapping, Op, + CodeRegion, CounterId, CovTerm, Expression, ExpressionId, FunctionCoverageInfo, Mapping, Op, }; use rustc_middle::ty::Instance; -#[derive(Clone, Debug, PartialEq)] -pub struct Expression { - lhs: CovTerm, - op: Op, - rhs: CovTerm, -} - /// Holds all of the coverage mapping data associated with a function instance, /// collected during traversal of `Coverage` statements in the function's MIR. #[derive(Debug)] @@ -26,7 +18,12 @@ pub struct FunctionCoverage<'tcx> { /// Tracks which counters have been seen, so that we can identify mappings /// to counters that were optimized out, and set them to zero. counters_seen: BitSet<CounterId>, - expressions: IndexVec<ExpressionId, Option<Expression>>, + /// 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> { @@ -52,16 +49,30 @@ impl<'tcx> FunctionCoverage<'tcx> { is_used: bool, ) -> Self { let num_counters = function_coverage_info.num_counters; - let num_expressions = function_coverage_info.num_expressions; + let num_expressions = function_coverage_info.expressions.len(); debug!( "FunctionCoverage::create(instance={instance:?}) has \ 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 { function_coverage_info, is_used, counters_seen: BitSet::new_empty(num_counters), - expressions: IndexVec::from_elem_n(None, num_expressions), + expressions_seen, } } @@ -76,35 +87,10 @@ impl<'tcx> FunctionCoverage<'tcx> { self.counters_seen.insert(id); } - /// Adds information about a coverage expression. + /// Marks an expression ID as having been seen in an expression-used statement. #[instrument(level = "debug", skip(self))] - pub(crate) fn add_counter_expression( - &mut self, - expression_id: ExpressionId, - lhs: CovTerm, - op: Op, - rhs: CovTerm, - ) { - 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 }; - 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" - ), - } + pub(crate) fn mark_expression_id_seen(&mut self, id: ExpressionId) { + self.expressions_seen.insert(id); } /// Identify expressions that will always have a value of zero, and note @@ -125,13 +111,13 @@ impl<'tcx> FunctionCoverage<'tcx> { // and then update the set of always-zero expressions if necessary. // (By construction, expressions can only refer to other expressions // that have lower IDs, so one pass is sufficient.) - for (id, maybe_expression) in self.expressions.iter_enumerated() { - let Some(expression) = maybe_expression else { - // If an expression is missing, it must have been optimized away, + for (id, expression) in self.function_coverage_info.expressions.iter_enumerated() { + if !self.expressions_seen.contains(id) { + // If an expression was not seen, it must have been optimized away, // so any operand that refers to it can be replaced with zero. zero_expressions.insert(id); continue; - }; + } // We don't need to simplify the actual expression data in the // expressions list; we can just simplify a temporary copy and then @@ -197,7 +183,7 @@ impl<'tcx> FunctionCoverage<'tcx> { // Expression IDs are indices into `self.expressions`, and on the LLVM // side they will be treated as indices into `counter_expressions`, so // 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(zero_expressions); @@ -217,27 +203,16 @@ impl<'tcx> FunctionCoverage<'tcx> { _ => Counter::from_term(operand), }; - self.expressions + self.function_coverage_info + .expressions .iter() - .map(|expression| match expression { - None => { - // This expression ID was allocated, but we never saw the - // 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::Subtract => ExprKind::Subtract, - }, - counter_from_operand(rhs), - ) - } + .map(|&Expression { lhs, op, rhs }| CounterExpression { + lhs: counter_from_operand(lhs), + kind: match op { + Op::Add => ExprKind::Add, + Op::Subtract => ExprKind::Subtract, + }, + rhs: counter_from_operand(rhs), }) .collect::<Vec<_>>() } diff --git a/compiler/rustc_codegen_llvm/src/coverageinfo/mod.rs b/compiler/rustc_codegen_llvm/src/coverageinfo/mod.rs index 14332927c8d..f6bc4783564 100644 --- a/compiler/rustc_codegen_llvm/src/coverageinfo/mod.rs +++ b/compiler/rustc_codegen_llvm/src/coverageinfo/mod.rs @@ -145,8 +145,8 @@ impl<'tcx> CoverageInfoBuilderMethods<'tcx> for Builder<'_, '_, 'tcx> { ); bx.instrprof_increment(fn_name, hash, num_counters, index); } - CoverageKind::Expression { id, lhs, op, rhs } => { - func_coverage.add_counter_expression(id, lhs, op, rhs); + CoverageKind::ExpressionUsed { id } => { + func_coverage.mark_expression_id_seen(id); } } } |