bjoernager/rust
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coverage: Disconnect span extraction from CoverageSpansGenerator

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By performal initial span extraction in a separate free function, we can remove
some accidental complexity from the main generator code.
This commit is contained in:
Zalathar 2023-10-01 21:07:42 +11:00
parent 972ab8863d
commit 4b471df25d
2 changed files with 88 additions and 90 deletions
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149
compiler/rustc_mir_transform/src/coverage/spans/from_mir.rs
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@ -3,86 +3,89 @@ use rustc_middle::mir::{
};
use rustc_span::Span;
use crate::coverage::graph::{BasicCoverageBlock, BasicCoverageBlockData};
use crate::coverage::spans::{CoverageSpan, CoverageSpansGenerator};
use crate::coverage::graph::{BasicCoverageBlock, BasicCoverageBlockData, CoverageGraph};
use crate::coverage::spans::CoverageSpan;
impl<'a, 'tcx> CoverageSpansGenerator<'a, 'tcx> {
pub(super) 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
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));
}
// 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),
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()
.enumerate()
.filter_map(move |(index, statement)| {
filtered_statement_span(statement).map(|span| {
CoverageSpan::for_statement(
statement,
function_source_span(span, body_span),
span,
bcb,
bb,
index,
)
}))
})
.collect()
}
})
})
.chain(filtered_terminator_span(data.terminator()).map(|span| {
CoverageSpan::for_terminator(
function_source_span(span, body_span),
span,
bcb,
bb,
)
}))
})
.collect()
}
/// If the MIR `Statement` has a span contributive to computing coverage spans,