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Make coverage counter IDs count up from 0, not 1

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Operand types are now tracked explicitly, so there is no need to reserve ID 0
for the special always-zero counter.

As part of the renumbering, this change fixes an off-by-one error in the way
counters were counted by the `coverageinfo` query. As a result, functions
should now have exactly the number of counters they actually need, instead of
always having an extra counter that is never used.
This commit is contained in:
Zalathar
2023-06-29 12:36:19 +10:00
parent f103db894f
commit 3920e07f0b
12 changed files with 43 additions and 61 deletions
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19
compiler/rustc_codegen_llvm/src/coverageinfo/map_data.rs
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@@ -3,7 +3,7 @@ pub use super::ffi::*;
use rustc_index::{IndexSlice, IndexVec};
use rustc_middle::bug;
use rustc_middle::mir::coverage::{
CodeRegion, CounterValueReference, ExpressionId, MappedExpressionIndex, Op, Operand,
CodeRegion, CounterId, ExpressionId, MappedExpressionIndex, Op, Operand,
};
use rustc_middle::ty::Instance;
use rustc_middle::ty::TyCtxt;
@@ -32,7 +32,7 @@ pub struct FunctionCoverage<'tcx> {
instance: Instance<'tcx>,
source_hash: u64,
is_used: bool,
counters: IndexVec<CounterValueReference, Option<CodeRegion>>,
counters: IndexVec<CounterId, Option<CodeRegion>>,
expressions: IndexVec<ExpressionId, Option<Expression>>,
unreachable_regions: Vec<CodeRegion>,
}
@@ -80,7 +80,7 @@ impl<'tcx> FunctionCoverage<'tcx> {
}
/// Adds a code region to be counted by an injected counter intrinsic.
pub fn add_counter(&mut self, id: CounterValueReference, region: CodeRegion) {
pub fn add_counter(&mut self, id: CounterId, region: CodeRegion) {
if let Some(previous_region) = self.counters[id].replace(region.clone()) {
assert_eq!(previous_region, region, "add_counter: code region for id changed");
}
@@ -192,18 +192,7 @@ impl<'tcx> FunctionCoverage<'tcx> {
type NewIndexes = IndexSlice<ExpressionId, Option<MappedExpressionIndex>>;
let id_to_counter = |new_indexes: &NewIndexes, operand: Operand| match operand {
Operand::Zero => Some(Counter::zero()),
Operand::Counter(id) => {
debug_assert!(
id.index() > 0,
"Operand::Counter indexes for counters are 1-based, but this id={}",
id.index()
);
// Note: Some codegen-injected Counters may be only referenced by `Expression`s,
// and may not have their own `CodeRegion`s,
let index = CounterValueReference::from(id.index());
// Note, the conversion to LLVM `Counter` adjusts the index to be zero-based.
Some(Counter::counter_value_reference(index))
}
Operand::Counter(id) => Some(Counter::counter_value_reference(id)),
Operand::Expression(id) => {
self.expressions
.get(id)