diff options
Diffstat (limited to 'compiler/rustc_middle/src')
| -rw-r--r-- | compiler/rustc_middle/src/mir/coverage.rs | 105 | ||||
| -rw-r--r-- | compiler/rustc_middle/src/mir/mod.rs | 10 | ||||
| -rw-r--r-- | compiler/rustc_middle/src/mir/pretty.rs | 29 | ||||
| -rw-r--r-- | compiler/rustc_middle/src/mir/query.rs | 24 | ||||
| -rw-r--r-- | compiler/rustc_middle/src/mir/syntax.rs | 18 | ||||
| -rw-r--r-- | compiler/rustc_middle/src/query/mod.rs | 20 |
6 files changed, 135 insertions, 71 deletions
diff --git a/compiler/rustc_middle/src/mir/coverage.rs b/compiler/rustc_middle/src/mir/coverage.rs index a6d6f6f5df4..08d377a8695 100644 --- a/compiler/rustc_middle/src/mir/coverage.rs +++ b/compiler/rustc_middle/src/mir/coverage.rs @@ -1,5 +1,6 @@ //! Metadata from source code coverage analysis and instrumentation. +use rustc_index::IndexVec; use rustc_macros::HashStable; use rustc_span::Symbol; @@ -8,6 +9,11 @@ use std::fmt::{self, Debug, Formatter}; rustc_index::newtype_index! { /// 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 /// to use a larger representation on the Rust side. #[derive(HashStable)] @@ -23,6 +29,11 @@ impl CounterId { rustc_index::newtype_index! { /// 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 /// to use a larger representation on the Rust side. #[derive(HashStable)] @@ -35,19 +46,21 @@ impl ExpressionId { 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 -/// expression. Counter/expression operands are referred to by ID. +/// This was originally only used for expression operands (and named `Operand`), +/// 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(TyEncodable, TyDecodable, Hash, HashStable, TypeFoldable, TypeVisitable)] -pub enum Operand { +pub enum CovTerm { Zero, Counter(CounterId), Expression(ExpressionId), } -impl Debug for Operand { +impl Debug for CovTerm { fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result { match self { Self::Zero => write!(f, "Zero"), @@ -59,40 +72,31 @@ impl Debug for Operand { #[derive(Clone, PartialEq, TyEncodable, TyDecodable, Hash, HashStable, TypeFoldable, TypeVisitable)] pub enum CoverageKind { - Counter { - function_source_hash: u64, - /// ID of this counter within its enclosing function. - /// Expressions in the same function can refer to it as an operand. - id: CounterId, - }, - Expression { - /// ID of this coverage-counter expression within its enclosing function. - /// Other expressions in the same function can refer to it as an operand. - id: ExpressionId, - lhs: Operand, - op: Op, - rhs: Operand, - }, - Unreachable, + /// Marks the point in MIR control flow represented by a coverage counter. + /// + /// This is eventually lowered to `llvm.instrprof.increment` in LLVM IR. + /// + /// If this statement does not survive MIR optimizations, any mappings that + /// refer to this counter can have those references simplified to zero. + CounterIncrement { id: CounterId }, + + /// Marks the point in MIR control-flow represented by a coverage expression. + /// + /// If this statement does not survive MIR optimizations, any mappings that + /// refer to this expression can have those references simplified to zero. + /// + /// (This is only inserted for expression IDs that are directly used by + /// mappings. Intermediate expressions with no direct mappings are + /// retained/zeroed based on whether they are transitively used.) + ExpressionUsed { id: ExpressionId }, } impl Debug for CoverageKind { fn fmt(&self, fmt: &mut Formatter<'_>) -> fmt::Result { use CoverageKind::*; match self { - Counter { id, .. } => write!(fmt, "Counter({:?})", id.index()), - Expression { id, lhs, op, rhs } => write!( - fmt, - "Expression({:?}) = {:?} {} {:?}", - id.index(), - lhs, - match op { - Op::Add => "+", - Op::Subtract => "-", - }, - rhs, - ), - Unreachable => write!(fmt, "Unreachable"), + CounterIncrement { id } => write!(fmt, "CounterIncrement({:?})", id.index()), + ExpressionUsed { id } => write!(fmt, "ExpressionUsed({:?})", id.index()), } } } @@ -133,3 +137,38 @@ impl Op { 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>, +} diff --git a/compiler/rustc_middle/src/mir/mod.rs b/compiler/rustc_middle/src/mir/mod.rs index f979f736b15..3a5ff4dc91f 100644 --- a/compiler/rustc_middle/src/mir/mod.rs +++ b/compiler/rustc_middle/src/mir/mod.rs @@ -345,6 +345,14 @@ pub struct Body<'tcx> { pub injection_phase: Option<MirPhase>, 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> { @@ -392,6 +400,7 @@ impl<'tcx> Body<'tcx> { is_polymorphic: false, injection_phase: None, tainted_by_errors, + function_coverage_info: None, }; body.is_polymorphic = body.has_non_region_param(); body @@ -420,6 +429,7 @@ impl<'tcx> Body<'tcx> { is_polymorphic: false, injection_phase: None, tainted_by_errors: None, + function_coverage_info: None, }; body.is_polymorphic = body.has_non_region_param(); body diff --git a/compiler/rustc_middle/src/mir/pretty.rs b/compiler/rustc_middle/src/mir/pretty.rs index c5e3ee575e1..3b3b61e4e21 100644 --- a/compiler/rustc_middle/src/mir/pretty.rs +++ b/compiler/rustc_middle/src/mir/pretty.rs @@ -493,6 +493,27 @@ pub fn write_mir_intro<'tcx>( // Add an empty line before the first block is printed. 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(()) } @@ -685,13 +706,7 @@ impl Debug for Statement<'_> { AscribeUserType(box (ref place, ref c_ty), ref variance) => { write!(fmt, "AscribeUserType({place:?}, {variance:?}, {c_ty:?})") } - Coverage(box mir::Coverage { ref kind, ref code_regions }) => { - if code_regions.is_empty() { - write!(fmt, "Coverage::{kind:?}") - } else { - write!(fmt, "Coverage::{kind:?} for {code_regions:?}") - } - } + Coverage(box mir::Coverage { ref kind }) => write!(fmt, "Coverage::{kind:?}"), Intrinsic(box ref intrinsic) => write!(fmt, "{intrinsic}"), ConstEvalCounter => write!(fmt, "ConstEvalCounter"), Nop => write!(fmt, "nop"), diff --git a/compiler/rustc_middle/src/mir/query.rs b/compiler/rustc_middle/src/mir/query.rs index c74a9536b63..f407dc4d7ae 100644 --- a/compiler/rustc_middle/src/mir/query.rs +++ b/compiler/rustc_middle/src/mir/query.rs @@ -1,5 +1,6 @@ //! Values computed by queries that use MIR. +use crate::mir; use crate::ty::{self, OpaqueHiddenType, Ty, TyCtxt}; use rustc_data_structures::fx::FxIndexMap; use rustc_data_structures::unord::UnordSet; @@ -445,14 +446,19 @@ pub struct DestructuredConstant<'tcx> { pub fields: &'tcx [(ConstValue<'tcx>, Ty<'tcx>)], } -/// Coverage information summarized from a MIR if instrumented for source code coverage (see -/// compiler option `-Cinstrument-coverage`). This information is generated by the -/// `InstrumentCoverage` MIR pass and can be retrieved via the `coverageinfo` query. +/// Summarizes coverage IDs inserted by the `InstrumentCoverage` MIR pass +/// (for compiler option `-Cinstrument-coverage`), after MIR optimizations +/// have had a chance to potentially remove some of them. +/// +/// Used by the `coverage_ids_info` query. #[derive(Clone, TyEncodable, TyDecodable, Debug, HashStable)] -pub struct CoverageInfo { - /// The total number of coverage region counters added to the MIR `Body`. - pub num_counters: u32, - - /// The total number of coverage region counter expressions added to the MIR `Body`. - pub num_expressions: u32, +pub struct CoverageIdsInfo { + /// Coverage codegen needs to know the highest counter ID that is ever + /// incremented within a function, so that it can set the `num-counters` + /// argument of the `llvm.instrprof.increment` intrinsic. + /// + /// 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, } diff --git a/compiler/rustc_middle/src/mir/syntax.rs b/compiler/rustc_middle/src/mir/syntax.rs index c7d99648f1e..7a645fb5d62 100644 --- a/compiler/rustc_middle/src/mir/syntax.rs +++ b/compiler/rustc_middle/src/mir/syntax.rs @@ -5,7 +5,7 @@ use super::{BasicBlock, Const, Local, UserTypeProjection}; -use crate::mir::coverage::{CodeRegion, CoverageKind}; +use crate::mir::coverage::CoverageKind; use crate::traits::Reveal; use crate::ty::adjustment::PointerCoercion; use crate::ty::GenericArgsRef; @@ -361,11 +361,16 @@ pub enum StatementKind<'tcx> { /// Disallowed after drop elaboration. AscribeUserType(Box<(Place<'tcx>, UserTypeProjection)>, ty::Variance), - /// Marks the start of a "coverage region", injected with '-Cinstrument-coverage'. A - /// `Coverage` statement carries metadata about the coverage region, used to inject a coverage - /// 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 - /// executed. + /// Carries control-flow-sensitive information injected by `-Cinstrument-coverage`, + /// such as where to generate physical coverage-counter-increments during codegen. + /// + /// Coverage statements are used in conjunction with the coverage mappings and other + /// 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>), /// 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)] pub struct Coverage { pub kind: CoverageKind, - pub code_regions: Vec<CodeRegion>, } #[derive(Clone, Debug, PartialEq, TyEncodable, TyDecodable, Hash, HashStable)] diff --git a/compiler/rustc_middle/src/query/mod.rs b/compiler/rustc_middle/src/query/mod.rs index 940ab190ffc..afe94d10752 100644 --- a/compiler/rustc_middle/src/query/mod.rs +++ b/compiler/rustc_middle/src/query/mod.rs @@ -573,24 +573,14 @@ rustc_queries! { separate_provide_extern } - /// Returns coverage summary info for a function, after executing the `InstrumentCoverage` - /// MIR pass (assuming the -Cinstrument-coverage option is enabled). - query coverageinfo(key: ty::InstanceDef<'tcx>) -> &'tcx mir::CoverageInfo { - desc { |tcx| "retrieving coverage info from MIR for `{}`", tcx.def_path_str(key.def_id()) } + /// Summarizes coverage IDs inserted by the `InstrumentCoverage` MIR pass + /// (for compiler option `-Cinstrument-coverage`), after MIR optimizations + /// have had a chance to potentially remove some of them. + 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 } - /// 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 /// `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 |