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coverage: Store expression data in function coverage info

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Even though expression details are now stored in the info structure, we still
need to inject `ExpressionUsed` statements into MIR, because if one is missing
during codegen then we know that it was optimized out and we can remap all of
its associated code regions to zero.
This commit is contained in:
Zalathar 2023-09-13 13:20:13 +10:00
parent 7d38f4a611
commit 13b2d604ec
9 changed files with 90 additions and 173 deletions
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41
compiler/rustc_middle/src/mir/coverage.rs
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@ -1,5 +1,6 @@
//! Metadata from source code coverage analysis and instrumentation.
use rustc_index::IndexVec;
use rustc_macros::HashStable;
use rustc_span::Symbol;
@ -68,14 +69,16 @@ pub enum CoverageKind {
/// 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 },
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: CovTerm,
op: Op,
rhs: CovTerm,
},
/// 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 {
@ -83,17 +86,7 @@ impl Debug for CoverageKind {
use CoverageKind::*;
match self {
CounterIncrement { id } => write!(fmt, "CounterIncrement({:?})", id.index()),
Expression { id, lhs, op, rhs } => write!(
fmt,
"Expression({:?}) = {:?} {} {:?}",
id.index(),
lhs,
match op {
Op::Add => "+",
Op::Subtract => "-",
},
rhs,
),
ExpressionUsed { id } => write!(fmt, "ExpressionUsed({:?})", id.index()),
}
}
}
@ -135,6 +128,14 @@ impl Op {
}
}
#[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 {
@ -157,7 +158,7 @@ pub struct Mapping {
pub struct FunctionCoverageInfo {
pub function_source_hash: u64,
pub num_counters: usize,
pub num_expressions: usize,
pub expressions: IndexVec<ExpressionId, Expression>,
pub mappings: Vec<Mapping>,
}