diff options
| -rw-r--r-- | compiler/rustc_codegen_llvm/src/coverageinfo/mod.rs | 3 | ||||
| -rw-r--r-- | compiler/rustc_middle/src/mir/coverage.rs | 8 | ||||
| -rw-r--r-- | compiler/rustc_mir_build/src/build/cfg.rs | 13 | ||||
| -rw-r--r-- | compiler/rustc_mir_transform/src/coverage/spans/from_mir.rs | 15 |
4 files changed, 36 insertions, 3 deletions
diff --git a/compiler/rustc_codegen_llvm/src/coverageinfo/mod.rs b/compiler/rustc_codegen_llvm/src/coverageinfo/mod.rs index 7d69756181a..8386f067baf 100644 --- a/compiler/rustc_codegen_llvm/src/coverageinfo/mod.rs +++ b/compiler/rustc_codegen_llvm/src/coverageinfo/mod.rs @@ -100,6 +100,9 @@ impl<'tcx> CoverageInfoBuilderMethods<'tcx> for Builder<'_, '_, 'tcx> { let Coverage { kind } = coverage; match *kind { + // Span markers are only meaningful during MIR instrumentation, + // and have no effect during codegen. + CoverageKind::SpanMarker => {} CoverageKind::CounterIncrement { id } => { func_coverage.mark_counter_id_seen(id); // We need to explicitly drop the `RefMut` before calling into `instrprof_increment`, diff --git a/compiler/rustc_middle/src/mir/coverage.rs b/compiler/rustc_middle/src/mir/coverage.rs index f15ee0082ce..ec5edceb269 100644 --- a/compiler/rustc_middle/src/mir/coverage.rs +++ b/compiler/rustc_middle/src/mir/coverage.rs @@ -76,6 +76,13 @@ impl Debug for CovTerm { #[derive(Clone, PartialEq, TyEncodable, TyDecodable, Hash, HashStable, TypeFoldable, TypeVisitable)] pub enum CoverageKind { + /// Marks a span that might otherwise not be represented in MIR, so that + /// coverage instrumentation can associate it with its enclosing block/BCB. + /// + /// Only used by the `InstrumentCoverage` pass, and has no effect during + /// codegen. + SpanMarker, + /// Marks the point in MIR control flow represented by a coverage counter. /// /// This is eventually lowered to `llvm.instrprof.increment` in LLVM IR. @@ -99,6 +106,7 @@ impl Debug for CoverageKind { fn fmt(&self, fmt: &mut Formatter<'_>) -> fmt::Result { use CoverageKind::*; match self { + SpanMarker => write!(fmt, "SpanMarker"), CounterIncrement { id } => write!(fmt, "CounterIncrement({:?})", id.index()), ExpressionUsed { id } => write!(fmt, "ExpressionUsed({:?})", id.index()), } diff --git a/compiler/rustc_mir_build/src/build/cfg.rs b/compiler/rustc_mir_build/src/build/cfg.rs index fddcf9de7c7..2bd0e289731 100644 --- a/compiler/rustc_mir_build/src/build/cfg.rs +++ b/compiler/rustc_mir_build/src/build/cfg.rs @@ -101,6 +101,19 @@ impl<'tcx> CFG<'tcx> { self.push(block, stmt); } + /// Adds a dummy statement whose only role is to associate a span with its + /// enclosing block for the purposes of coverage instrumentation. + /// + /// This results in more accurate coverage reports for certain kinds of + /// syntax (e.g. `continue` or `if !`) that would otherwise not appear in MIR. + pub(crate) fn push_coverage_span_marker(&mut self, block: BasicBlock, source_info: SourceInfo) { + let kind = StatementKind::Coverage(Box::new(Coverage { + kind: coverage::CoverageKind::SpanMarker, + })); + let stmt = Statement { source_info, kind }; + self.push(block, stmt); + } + pub(crate) fn terminate( &mut self, block: BasicBlock, diff --git a/compiler/rustc_mir_transform/src/coverage/spans/from_mir.rs b/compiler/rustc_mir_transform/src/coverage/spans/from_mir.rs index e1531f2c239..6f7d8d9dd75 100644 --- a/compiler/rustc_mir_transform/src/coverage/spans/from_mir.rs +++ b/compiler/rustc_mir_transform/src/coverage/spans/from_mir.rs @@ -92,13 +92,13 @@ fn is_closure(statement: &Statement<'_>) -> bool { /// If the MIR `Statement` has a span contributive to computing coverage spans, /// return it; otherwise return `None`. fn filtered_statement_span(statement: &Statement<'_>) -> Option<Span> { + use mir::coverage::CoverageKind; + match statement.kind { // These statements have spans that are often outside the scope of the executed source code // for their parent `BasicBlock`. StatementKind::StorageLive(_) | StatementKind::StorageDead(_) - // Coverage should not be encountered, but don't inject coverage coverage - | StatementKind::Coverage(_) // Ignore `ConstEvalCounter`s | StatementKind::ConstEvalCounter // Ignore `Nop`s @@ -122,9 +122,13 @@ fn filtered_statement_span(statement: &Statement<'_>) -> Option<Span> { // If and when the Issue is resolved, remove this special case match pattern: StatementKind::FakeRead(box (FakeReadCause::ForGuardBinding, _)) => None, - // Retain spans from all other statements + // Retain spans from most other statements. StatementKind::FakeRead(box (_, _)) // Not including `ForGuardBinding` | StatementKind::Intrinsic(..) + | StatementKind::Coverage(box mir::Coverage { + // The purpose of `SpanMarker` is to be matched and accepted here. + kind: CoverageKind::SpanMarker + }) | StatementKind::Assign(_) | StatementKind::SetDiscriminant { .. } | StatementKind::Deinit(..) @@ -133,6 +137,11 @@ fn filtered_statement_span(statement: &Statement<'_>) -> Option<Span> { | StatementKind::AscribeUserType(_, _) => { Some(statement.source_info.span) } + + StatementKind::Coverage(box mir::Coverage { + // These coverage statements should not exist prior to coverage instrumentation. + kind: CoverageKind::CounterIncrement { .. } | CoverageKind::ExpressionUsed { .. } + }) => bug!("Unexpected coverage statement found during coverage instrumentation: {statement:?}"), } } |