diff options
| -rw-r--r-- | compiler/rustc_mir_transform/src/coverage/spans.rs | 268 | ||||
| -rw-r--r-- | compiler/rustc_mir_transform/src/coverage/spans/from_mir.rs | 184 |
2 files changed, 215 insertions, 237 deletions
diff --git a/compiler/rustc_mir_transform/src/coverage/spans.rs b/compiler/rustc_mir_transform/src/coverage/spans.rs index dd87694f97c..e08019bea21 100644 --- a/compiler/rustc_mir_transform/src/coverage/spans.rs +++ b/compiler/rustc_mir_transform/src/coverage/spans.rs @@ -1,15 +1,13 @@ -use super::graph::{BasicCoverageBlock, BasicCoverageBlockData, CoverageGraph, START_BCB}; +use std::cell::OnceCell; use rustc_data_structures::graph::WithNumNodes; use rustc_index::IndexVec; -use rustc_middle::mir::{ - self, AggregateKind, BasicBlock, FakeReadCause, Rvalue, Statement, StatementKind, Terminator, - TerminatorKind, -}; -use rustc_span::source_map::original_sp; +use rustc_middle::mir::{self, AggregateKind, Rvalue, Statement, StatementKind}; use rustc_span::{BytePos, ExpnKind, MacroKind, Span, Symbol}; -use std::cell::OnceCell; +use super::graph::{BasicCoverageBlock, CoverageGraph, START_BCB}; + +mod from_mir; pub(super) struct CoverageSpans { /// Map from BCBs to their list of coverage spans. @@ -53,27 +51,13 @@ impl CoverageSpans { } } -#[derive(Debug, Copy, Clone)] -pub(super) enum CoverageStatement { - Statement(BasicBlock, Span, usize), - Terminator(BasicBlock, Span), -} - -impl CoverageStatement { - pub fn span(&self) -> Span { - match self { - Self::Statement(_, span, _) | Self::Terminator(_, span) => *span, - } - } -} - /// A BCB is deconstructed into one or more `Span`s. Each `Span` maps to a `CoverageSpan` that /// references the originating BCB and one or more MIR `Statement`s and/or `Terminator`s. /// Initially, the `Span`s come from the `Statement`s and `Terminator`s, but subsequent /// transforms can combine adjacent `Span`s and `CoverageSpan` from the same BCB, merging the -/// `CoverageStatement` vectors, and the `Span`s to cover the extent of the combined `Span`s. +/// `merged_spans` vectors, and the `Span`s to cover the extent of the combined `Span`s. /// -/// Note: A `CoverageStatement` merged into another CoverageSpan may come from a `BasicBlock` that +/// Note: A span merged into another CoverageSpan may come from a `BasicBlock` that /// is not part of the `CoverageSpan` bcb if the statement was included because it's `Span` matches /// or is subsumed by the `Span` associated with this `CoverageSpan`, and it's `BasicBlock` /// `dominates()` the `BasicBlock`s in this `CoverageSpan`. @@ -83,7 +67,9 @@ struct CoverageSpan { pub expn_span: Span, pub current_macro_or_none: OnceCell<Option<Symbol>>, pub bcb: BasicCoverageBlock, - pub coverage_statements: Vec<CoverageStatement>, + /// List of all the original spans from MIR that have been merged into this + /// span. Mainly used to precisely skip over gaps when truncating a span. + pub merged_spans: Vec<Span>, pub is_closure: bool, } @@ -94,7 +80,7 @@ impl CoverageSpan { expn_span: fn_sig_span, current_macro_or_none: Default::default(), bcb: START_BCB, - coverage_statements: vec![], + merged_spans: vec![], is_closure: false, } } @@ -104,8 +90,6 @@ impl CoverageSpan { span: Span, expn_span: Span, bcb: BasicCoverageBlock, - bb: BasicBlock, - stmt_index: usize, ) -> Self { let is_closure = match statement.kind { StatementKind::Assign(box (_, Rvalue::Aggregate(box ref kind, _))) => { @@ -119,23 +103,18 @@ impl CoverageSpan { expn_span, current_macro_or_none: Default::default(), bcb, - coverage_statements: vec![CoverageStatement::Statement(bb, span, stmt_index)], + merged_spans: vec![span], is_closure, } } - pub fn for_terminator( - span: Span, - expn_span: Span, - bcb: BasicCoverageBlock, - bb: BasicBlock, - ) -> Self { + pub fn for_terminator(span: Span, expn_span: Span, bcb: BasicCoverageBlock) -> Self { Self { span, expn_span, current_macro_or_none: Default::default(), bcb, - coverage_statements: vec![CoverageStatement::Terminator(bb, span)], + merged_spans: vec![span], is_closure: false, } } @@ -143,15 +122,13 @@ impl CoverageSpan { pub fn merge_from(&mut self, mut other: CoverageSpan) { debug_assert!(self.is_mergeable(&other)); self.span = self.span.to(other.span); - self.coverage_statements.append(&mut other.coverage_statements); + self.merged_spans.append(&mut other.merged_spans); } pub fn cutoff_statements_at(&mut self, cutoff_pos: BytePos) { - self.coverage_statements.retain(|covstmt| covstmt.span().hi() <= cutoff_pos); - if let Some(highest_covstmt) = - self.coverage_statements.iter().max_by_key(|covstmt| covstmt.span().hi()) - { - self.span = self.span.with_hi(highest_covstmt.span().hi()); + self.merged_spans.retain(|span| span.hi() <= cutoff_pos); + if let Some(max_hi) = self.merged_spans.iter().map(|span| span.hi()).max() { + self.span = self.span.with_hi(max_hi); } } @@ -205,13 +182,7 @@ impl CoverageSpan { /// * Merge spans that represent continuous (both in source code and control flow), non-branching /// execution /// * Carve out (leave uncovered) any span that will be counted by another MIR (notably, closures) -struct CoverageSpansGenerator<'a, 'tcx> { - /// The MIR, used to look up `BasicBlockData`. - mir_body: &'a mir::Body<'tcx>, - - /// A `Span` covering the signature of function for the MIR. - fn_sig_span: Span, - +struct CoverageSpansGenerator<'a> { /// A `Span` covering the function body of the MIR (typically from left curly brace to right /// curly brace). body_span: Span, @@ -221,7 +192,7 @@ struct CoverageSpansGenerator<'a, 'tcx> { /// The initial set of `CoverageSpan`s, sorted by `Span` (`lo` and `hi`) and by relative /// dominance between the `BasicCoverageBlock`s of equal `Span`s. - sorted_spans_iter: Option<std::vec::IntoIter<CoverageSpan>>, + sorted_spans_iter: std::vec::IntoIter<CoverageSpan>, /// The current `CoverageSpan` to compare to its `prev`, to possibly merge, discard, force the /// discard of the `prev` (and or `pending_dups`), or keep both (with `prev` moved to @@ -261,7 +232,7 @@ struct CoverageSpansGenerator<'a, 'tcx> { refined_spans: Vec<CoverageSpan>, } -impl<'a, 'tcx> CoverageSpansGenerator<'a, 'tcx> { +impl<'a> CoverageSpansGenerator<'a> { /// Generate a minimal set of `CoverageSpan`s, each representing a contiguous code region to be /// counted. /// @@ -284,17 +255,22 @@ impl<'a, 'tcx> CoverageSpansGenerator<'a, 'tcx> { /// Note the resulting vector of `CoverageSpan`s may not be fully sorted (and does not need /// to be). pub(super) fn generate_coverage_spans( - mir_body: &'a mir::Body<'tcx>, + mir_body: &mir::Body<'_>, fn_sig_span: Span, // Ensured to be same SourceFile and SyntaxContext as `body_span` body_span: Span, basic_coverage_blocks: &'a CoverageGraph, ) -> Vec<CoverageSpan> { - let mut coverage_spans = Self { + let sorted_spans = from_mir::mir_to_initial_sorted_coverage_spans( mir_body, fn_sig_span, body_span, basic_coverage_blocks, - sorted_spans_iter: None, + ); + + let coverage_spans = Self { + body_span, + basic_coverage_blocks, + sorted_spans_iter: sorted_spans.into_iter(), refined_spans: Vec::with_capacity(basic_coverage_blocks.num_nodes() * 2), some_curr: None, curr_original_span: Span::with_root_ctxt(BytePos(0), BytePos(0)), @@ -304,48 +280,9 @@ impl<'a, 'tcx> CoverageSpansGenerator<'a, 'tcx> { pending_dups: Vec::new(), }; - let sorted_spans = coverage_spans.mir_to_initial_sorted_coverage_spans(); - - coverage_spans.sorted_spans_iter = Some(sorted_spans.into_iter()); - coverage_spans.to_refined_spans() } - fn mir_to_initial_sorted_coverage_spans(&self) -> Vec<CoverageSpan> { - let mut initial_spans = - Vec::<CoverageSpan>::with_capacity(self.mir_body.basic_blocks.len() * 2); - for (bcb, bcb_data) in self.basic_coverage_blocks.iter_enumerated() { - initial_spans.extend(self.bcb_to_initial_coverage_spans(bcb, bcb_data)); - } - - if initial_spans.is_empty() { - // This can happen if, for example, the function is unreachable (contains only a - // `BasicBlock`(s) with an `Unreachable` terminator). - return initial_spans; - } - - initial_spans.push(CoverageSpan::for_fn_sig(self.fn_sig_span)); - - initial_spans.sort_by(|a, b| { - // First sort by span start. - Ord::cmp(&a.span.lo(), &b.span.lo()) - // If span starts are the same, sort by span end in reverse order. - // This ensures that if spans A and B are adjacent in the list, - // and they overlap but are not equal, then either: - // - Span A extends further left, or - // - Both have the same start and span A extends further right - .then_with(|| Ord::cmp(&a.span.hi(), &b.span.hi()).reverse()) - // If both spans are equal, sort the BCBs in dominator order, - // so that dominating BCBs come before other BCBs they dominate. - .then_with(|| self.basic_coverage_blocks.cmp_in_dominator_order(a.bcb, b.bcb)) - // If two spans are otherwise identical, put closure spans first, - // as this seems to be what the refinement step expects. - .then_with(|| Ord::cmp(&a.is_closure, &b.is_closure).reverse()) - }); - - initial_spans - } - /// Iterate through the sorted `CoverageSpan`s, and return the refined list of merged and /// de-duplicated `CoverageSpan`s. fn to_refined_spans(mut self) -> Vec<CoverageSpan> { @@ -485,48 +422,6 @@ impl<'a, 'tcx> CoverageSpansGenerator<'a, 'tcx> { } } - // Generate a set of `CoverageSpan`s from the filtered set of `Statement`s and `Terminator`s of - // the `BasicBlock`(s) in the given `BasicCoverageBlockData`. One `CoverageSpan` is generated - // for each `Statement` and `Terminator`. (Note that subsequent stages of coverage analysis will - // merge some `CoverageSpan`s, at which point a `CoverageSpan` may represent multiple - // `Statement`s and/or `Terminator`s.) - fn bcb_to_initial_coverage_spans( - &self, - bcb: BasicCoverageBlock, - bcb_data: &'a BasicCoverageBlockData, - ) -> Vec<CoverageSpan> { - bcb_data - .basic_blocks - .iter() - .flat_map(|&bb| { - let data = &self.mir_body[bb]; - data.statements - .iter() - .enumerate() - .filter_map(move |(index, statement)| { - filtered_statement_span(statement).map(|span| { - CoverageSpan::for_statement( - statement, - function_source_span(span, self.body_span), - span, - bcb, - bb, - index, - ) - }) - }) - .chain(filtered_terminator_span(data.terminator()).map(|span| { - CoverageSpan::for_terminator( - function_source_span(span, self.body_span), - span, - bcb, - bb, - ) - })) - }) - .collect() - } - fn curr(&self) -> &CoverageSpan { self.some_curr .as_ref() @@ -589,7 +484,7 @@ impl<'a, 'tcx> CoverageSpansGenerator<'a, 'tcx> { self.some_prev = Some(curr); self.prev_original_span = self.curr_original_span; } - while let Some(curr) = self.sorted_spans_iter.as_mut().unwrap().next() { + while let Some(curr) = self.sorted_spans_iter.next() { debug!("FOR curr={:?}", curr); if self.some_prev.is_some() && self.prev_starts_after_next(&curr) { debug!( @@ -757,7 +652,7 @@ impl<'a, 'tcx> CoverageSpansGenerator<'a, 'tcx> { if self.pending_dups.is_empty() { let curr_span = self.curr().span; self.prev_mut().cutoff_statements_at(curr_span.lo()); - if self.prev().coverage_statements.is_empty() { + if self.prev().merged_spans.is_empty() { debug!(" ... no non-overlapping statements to add"); } else { debug!(" ... adding modified prev={:?}", self.prev()); @@ -774,104 +669,3 @@ impl<'a, 'tcx> CoverageSpansGenerator<'a, 'tcx> { self.basic_coverage_blocks.dominates(dom_covspan.bcb, covspan.bcb) } } - -/// 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> { - 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 - | StatementKind::Nop => None, - - // FIXME(#78546): MIR InstrumentCoverage - Can the source_info.span for `FakeRead` - // statements be more consistent? - // - // FakeReadCause::ForGuardBinding, in this example: - // match somenum { - // x if x < 1 => { ... } - // }... - // The BasicBlock within the match arm code included one of these statements, but the span - // for it covered the `1` in this source. The actual statements have nothing to do with that - // source span: - // FakeRead(ForGuardBinding, _4); - // where `_4` is: - // _4 = &_1; (at the span for the first `x`) - // and `_1` is the `Place` for `somenum`. - // - // 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 - StatementKind::FakeRead(box (_, _)) // Not including `ForGuardBinding` - | StatementKind::Intrinsic(..) - | StatementKind::Assign(_) - | StatementKind::SetDiscriminant { .. } - | StatementKind::Deinit(..) - | StatementKind::Retag(_, _) - | StatementKind::PlaceMention(..) - | StatementKind::AscribeUserType(_, _) => { - Some(statement.source_info.span) - } - } -} - -/// If the MIR `Terminator` has a span contributive to computing coverage spans, -/// return it; otherwise return `None`. -fn filtered_terminator_span(terminator: &Terminator<'_>) -> Option<Span> { - match terminator.kind { - // These terminators have spans that don't positively contribute to computing a reasonable - // span of actually executed source code. (For example, SwitchInt terminators extracted from - // an `if condition { block }` has a span that includes the executed block, if true, - // but for coverage, the code region executed, up to *and* through the SwitchInt, - // actually stops before the if's block.) - TerminatorKind::Unreachable // Unreachable blocks are not connected to the MIR CFG - | TerminatorKind::Assert { .. } - | TerminatorKind::Drop { .. } - | TerminatorKind::SwitchInt { .. } - // For `FalseEdge`, only the `real` branch is taken, so it is similar to a `Goto`. - | TerminatorKind::FalseEdge { .. } - | TerminatorKind::Goto { .. } => None, - - // Call `func` operand can have a more specific span when part of a chain of calls - | TerminatorKind::Call { ref func, .. } => { - let mut span = terminator.source_info.span; - if let mir::Operand::Constant(box constant) = func { - if constant.span.lo() > span.lo() { - span = span.with_lo(constant.span.lo()); - } - } - Some(span) - } - - // Retain spans from all other terminators - TerminatorKind::UnwindResume - | TerminatorKind::UnwindTerminate(_) - | TerminatorKind::Return - | TerminatorKind::Yield { .. } - | TerminatorKind::GeneratorDrop - | TerminatorKind::FalseUnwind { .. } - | TerminatorKind::InlineAsm { .. } => { - Some(terminator.source_info.span) - } - } -} - -/// Returns an extrapolated span (pre-expansion[^1]) corresponding to a range -/// within the function's body source. This span is guaranteed to be contained -/// within, or equal to, the `body_span`. If the extrapolated span is not -/// contained within the `body_span`, the `body_span` is returned. -/// -/// [^1]Expansions result from Rust syntax including macros, syntactic sugar, -/// etc.). -#[inline] -fn function_source_span(span: Span, body_span: Span) -> Span { - let original_span = original_sp(span, body_span).with_ctxt(body_span.ctxt()); - if body_span.contains(original_span) { original_span } else { body_span } -} diff --git a/compiler/rustc_mir_transform/src/coverage/spans/from_mir.rs b/compiler/rustc_mir_transform/src/coverage/spans/from_mir.rs new file mode 100644 index 00000000000..4c20997e633 --- /dev/null +++ b/compiler/rustc_mir_transform/src/coverage/spans/from_mir.rs @@ -0,0 +1,184 @@ +use rustc_middle::mir::{ + self, FakeReadCause, Statement, StatementKind, Terminator, TerminatorKind, +}; +use rustc_span::Span; + +use crate::coverage::graph::{BasicCoverageBlock, BasicCoverageBlockData, CoverageGraph}; +use crate::coverage::spans::CoverageSpan; + +pub(super) fn mir_to_initial_sorted_coverage_spans( + mir_body: &mir::Body<'_>, + fn_sig_span: Span, + body_span: Span, + basic_coverage_blocks: &CoverageGraph, +) -> Vec<CoverageSpan> { + let mut initial_spans = Vec::<CoverageSpan>::with_capacity(mir_body.basic_blocks.len() * 2); + for (bcb, bcb_data) in basic_coverage_blocks.iter_enumerated() { + initial_spans.extend(bcb_to_initial_coverage_spans(mir_body, body_span, bcb, bcb_data)); + } + + if initial_spans.is_empty() { + // This can happen if, for example, the function is unreachable (contains only a + // `BasicBlock`(s) with an `Unreachable` terminator). + return initial_spans; + } + + initial_spans.push(CoverageSpan::for_fn_sig(fn_sig_span)); + + initial_spans.sort_by(|a, b| { + // First sort by span start. + Ord::cmp(&a.span.lo(), &b.span.lo()) + // If span starts are the same, sort by span end in reverse order. + // This ensures that if spans A and B are adjacent in the list, + // and they overlap but are not equal, then either: + // - Span A extends further left, or + // - Both have the same start and span A extends further right + .then_with(|| Ord::cmp(&a.span.hi(), &b.span.hi()).reverse()) + // If both spans are equal, sort the BCBs in dominator order, + // so that dominating BCBs come before other BCBs they dominate. + .then_with(|| basic_coverage_blocks.cmp_in_dominator_order(a.bcb, b.bcb)) + // If two spans are otherwise identical, put closure spans first, + // as this seems to be what the refinement step expects. + .then_with(|| Ord::cmp(&a.is_closure, &b.is_closure).reverse()) + }); + + initial_spans +} + +// Generate a set of `CoverageSpan`s from the filtered set of `Statement`s and `Terminator`s of +// the `BasicBlock`(s) in the given `BasicCoverageBlockData`. One `CoverageSpan` is generated +// for each `Statement` and `Terminator`. (Note that subsequent stages of coverage analysis will +// merge some `CoverageSpan`s, at which point a `CoverageSpan` may represent multiple +// `Statement`s and/or `Terminator`s.) +fn bcb_to_initial_coverage_spans( + mir_body: &mir::Body<'_>, + body_span: Span, + bcb: BasicCoverageBlock, + bcb_data: &BasicCoverageBlockData, +) -> Vec<CoverageSpan> { + bcb_data + .basic_blocks + .iter() + .flat_map(|&bb| { + let data = &mir_body[bb]; + data.statements + .iter() + .filter_map(move |statement| { + filtered_statement_span(statement).map(|span| { + CoverageSpan::for_statement( + statement, + function_source_span(span, body_span), + span, + bcb, + ) + }) + }) + .chain(filtered_terminator_span(data.terminator()).map(|span| { + CoverageSpan::for_terminator(function_source_span(span, body_span), span, bcb) + })) + }) + .collect() +} + +/// 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> { + 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 + | StatementKind::Nop => None, + + // FIXME(#78546): MIR InstrumentCoverage - Can the source_info.span for `FakeRead` + // statements be more consistent? + // + // FakeReadCause::ForGuardBinding, in this example: + // match somenum { + // x if x < 1 => { ... } + // }... + // The BasicBlock within the match arm code included one of these statements, but the span + // for it covered the `1` in this source. The actual statements have nothing to do with that + // source span: + // FakeRead(ForGuardBinding, _4); + // where `_4` is: + // _4 = &_1; (at the span for the first `x`) + // and `_1` is the `Place` for `somenum`. + // + // 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 + StatementKind::FakeRead(box (_, _)) // Not including `ForGuardBinding` + | StatementKind::Intrinsic(..) + | StatementKind::Assign(_) + | StatementKind::SetDiscriminant { .. } + | StatementKind::Deinit(..) + | StatementKind::Retag(_, _) + | StatementKind::PlaceMention(..) + | StatementKind::AscribeUserType(_, _) => { + Some(statement.source_info.span) + } + } +} + +/// If the MIR `Terminator` has a span contributive to computing coverage spans, +/// return it; otherwise return `None`. +fn filtered_terminator_span(terminator: &Terminator<'_>) -> Option<Span> { + match terminator.kind { + // These terminators have spans that don't positively contribute to computing a reasonable + // span of actually executed source code. (For example, SwitchInt terminators extracted from + // an `if condition { block }` has a span that includes the executed block, if true, + // but for coverage, the code region executed, up to *and* through the SwitchInt, + // actually stops before the if's block.) + TerminatorKind::Unreachable // Unreachable blocks are not connected to the MIR CFG + | TerminatorKind::Assert { .. } + | TerminatorKind::Drop { .. } + | TerminatorKind::SwitchInt { .. } + // For `FalseEdge`, only the `real` branch is taken, so it is similar to a `Goto`. + | TerminatorKind::FalseEdge { .. } + | TerminatorKind::Goto { .. } => None, + + // Call `func` operand can have a more specific span when part of a chain of calls + | TerminatorKind::Call { ref func, .. } => { + let mut span = terminator.source_info.span; + if let mir::Operand::Constant(box constant) = func { + if constant.span.lo() > span.lo() { + span = span.with_lo(constant.span.lo()); + } + } + Some(span) + } + + // Retain spans from all other terminators + TerminatorKind::UnwindResume + | TerminatorKind::UnwindTerminate(_) + | TerminatorKind::Return + | TerminatorKind::Yield { .. } + | TerminatorKind::GeneratorDrop + | TerminatorKind::FalseUnwind { .. } + | TerminatorKind::InlineAsm { .. } => { + Some(terminator.source_info.span) + } + } +} + +/// Returns an extrapolated span (pre-expansion[^1]) corresponding to a range +/// within the function's body source. This span is guaranteed to be contained +/// within, or equal to, the `body_span`. If the extrapolated span is not +/// contained within the `body_span`, the `body_span` is returned. +/// +/// [^1]Expansions result from Rust syntax including macros, syntactic sugar, +/// etc.). +#[inline] +fn function_source_span(span: Span, body_span: Span) -> Span { + use rustc_span::source_map::original_sp; + + let original_span = original_sp(span, body_span).with_ctxt(body_span.ctxt()); + if body_span.contains(original_span) { original_span } else { body_span } +} |