bjoernager/rust
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Replace ExpressionOperandId with enum Operand

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Because the three kinds of operand are now distinguished explicitly, we no
longer need fiddly code to disambiguate counter IDs and expression IDs based on
the total number of counters/expressions in a function.

This does increase the size of operands from 4 bytes to 8 bytes, but that
shouldn't be a big deal since they are mostly stored inside boxed structures,
and the current coverage code is not particularly size-optimized anyway.
This commit is contained in:
Zalathar 2023-06-26 22:28:48 +10:00
parent 5a808d40f4
commit 1a014d42f4
11 changed files with 96 additions and 147 deletions
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45
compiler/rustc_mir_transform/src/coverage/query.rs
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@ -47,39 +47,24 @@ impl CoverageVisitor {
/// final computed number of counters should be the number of all `CoverageKind::Counter`
/// statements in the MIR *plus one* for the implicit `ZERO` counter.
#[inline(always)]
fn update_num_counters(&mut self, counter_id: u32) {
fn update_num_counters(&mut self, counter_id: CounterValueReference) {
let counter_id = counter_id.as_u32();
self.info.num_counters = std::cmp::max(self.info.num_counters, counter_id + 1);
}
/// Computes an expression index for each expression ID, and updates `num_expressions` to the
/// maximum encountered index plus 1.
#[inline(always)]
fn update_num_expressions(&mut self, expression_id: u32) {
let expression_index = u32::MAX - expression_id;
fn update_num_expressions(&mut self, expression_id: InjectedExpressionId) {
let expression_index = u32::MAX - expression_id.as_u32();
self.info.num_expressions = std::cmp::max(self.info.num_expressions, expression_index + 1);
}
fn update_from_expression_operand(&mut self, operand_id: u32) {
if operand_id >= self.info.num_counters {
let operand_as_expression_index = u32::MAX - operand_id;
if operand_as_expression_index >= self.info.num_expressions {
// The operand ID is outside the known range of counter IDs and also outside the
// known range of expression IDs. In either case, the result of a missing operand
// (if and when used in an expression) will be zero, so from a computation
// perspective, it doesn't matter whether it is interpreted as a counter or an
// expression.
//
// However, the `num_counters` and `num_expressions` query results are used to
// allocate arrays when generating the coverage map (during codegen), so choose
// the type that grows either `num_counters` or `num_expressions` the least.
if operand_id - self.info.num_counters
< operand_as_expression_index - self.info.num_expressions
{
self.update_num_counters(operand_id)
} else {
self.update_num_expressions(operand_id)
}
}
fn update_from_expression_operand(&mut self, operand: Operand) {
match operand {
Operand::Counter(id) => self.update_num_counters(id),
Operand::Expression(id) => self.update_num_expressions(id),
Operand::Zero => {}
}
}
@ -100,19 +85,15 @@ impl CoverageVisitor {
if self.add_missing_operands {
match coverage.kind {
CoverageKind::Expression { lhs, rhs, .. } => {
self.update_from_expression_operand(u32::from(lhs));
self.update_from_expression_operand(u32::from(rhs));
self.update_from_expression_operand(lhs);
self.update_from_expression_operand(rhs);
}
_ => {}
}
} else {
match coverage.kind {
CoverageKind::Counter { id, .. } => {
self.update_num_counters(u32::from(id));
}
CoverageKind::Expression { id, .. } => {
self.update_num_expressions(u32::from(id));
}
CoverageKind::Counter { id, .. } => self.update_num_counters(id),
CoverageKind::Expression { id, .. } => self.update_num_expressions(id),
_ => {}
}
}