bjoernager/rust
bjoernager/rust
1
Fork 0
Code Issues Pull requests Activity

Revert "Rollup merge of #133418 - Zalathar:spans, r=jieyouxu"

Browse source 
This reverts commit adf9b5fcd1, reversing
changes made to af1ca153d4.

Reverting due to <https://github.com/rust-lang/rust/issues/133606>.
This commit is contained in:
Zalathar 2024-11-29 14:52:41 +11:00
parent d53f0b1d8e
commit 9461f4296f
13 changed files with 284 additions and 250 deletions
Download patch file Download diff file Expand all files Collapse all files

166
compiler/rustc_mir_transform/src/coverage/mod.rs
View file

@ -13,15 +13,16 @@ use rustc_hir::intravisit::{Visitor, walk_expr};
use rustc_middle::hir::map::Map;
use rustc_middle::hir::nested_filter;
use rustc_middle::mir::coverage::{
CoverageKind, DecisionInfo, FunctionCoverageInfo, Mapping, MappingKind,
CoverageKind, DecisionInfo, FunctionCoverageInfo, Mapping, MappingKind, SourceRegion,
};
use rustc_middle::mir::{
self, BasicBlock, BasicBlockData, SourceInfo, Statement, StatementKind, Terminator,
TerminatorKind,
};
use rustc_middle::ty::TyCtxt;
use rustc_span::Span;
use rustc_span::def_id::LocalDefId;
use rustc_span::source_map::SourceMap;
use rustc_span::{BytePos, Pos, SourceFile, Span};
use tracing::{debug, debug_span, trace};
use crate::coverage::counters::{CounterIncrementSite, CoverageCounters};
@ -96,7 +97,7 @@ fn instrument_function_for_coverage<'tcx>(tcx: TyCtxt<'tcx>, mir_body: &mut mir:
let coverage_counters =
CoverageCounters::make_bcb_counters(&basic_coverage_blocks, &bcbs_with_counter_mappings);
let mappings = create_mappings(&extracted_mappings, &coverage_counters);
let mappings = create_mappings(tcx, &hir_info, &extracted_mappings, &coverage_counters);
if mappings.is_empty() {
// No spans could be converted into valid mappings, so skip this function.
debug!("no spans could be converted into valid mappings; skipping");
@ -135,12 +136,18 @@ fn instrument_function_for_coverage<'tcx>(tcx: TyCtxt<'tcx>, mir_body: &mut mir:
///
/// Precondition: All BCBs corresponding to those spans have been given
/// coverage counters.
fn create_mappings(
fn create_mappings<'tcx>(
tcx: TyCtxt<'tcx>,
hir_info: &ExtractedHirInfo,
extracted_mappings: &ExtractedMappings,
coverage_counters: &CoverageCounters,
) -> Vec<Mapping> {
let source_map = tcx.sess.source_map();
let file = source_map.lookup_source_file(hir_info.body_span.lo());
let term_for_bcb =
|bcb| coverage_counters.term_for_bcb(bcb).expect("all BCBs with spans were given counters");
let region_for_span = |span: Span| make_source_region(source_map, hir_info, &file, span);
// Fully destructure the mappings struct to make sure we don't miss any kinds.
let ExtractedMappings {
@ -153,20 +160,22 @@ fn create_mappings(
} = extracted_mappings;
let mut mappings = Vec::new();
mappings.extend(code_mappings.iter().map(
mappings.extend(code_mappings.iter().filter_map(
// Ordinary code mappings are the simplest kind.
|&mappings::CodeMapping { span, bcb }| {
let source_region = region_for_span(span)?;
let kind = MappingKind::Code(term_for_bcb(bcb));
Mapping { kind, span }
Some(Mapping { kind, source_region })
},
));
mappings.extend(branch_pairs.iter().map(
mappings.extend(branch_pairs.iter().filter_map(
|&mappings::BranchPair { span, true_bcb, false_bcb }| {
let true_term = term_for_bcb(true_bcb);
let false_term = term_for_bcb(false_bcb);
let kind = MappingKind::Branch { true_term, false_term };
Mapping { kind, span }
let source_region = region_for_span(span)?;
Some(Mapping { kind, source_region })
},
));
@ -174,7 +183,7 @@ fn create_mappings(
|bcb| coverage_counters.term_for_bcb(bcb).expect("all BCBs with spans were given counters");
// MCDC branch mappings are appended with their decisions in case decisions were ignored.
mappings.extend(mcdc_degraded_branches.iter().map(
mappings.extend(mcdc_degraded_branches.iter().filter_map(
|&mappings::MCDCBranch {
span,
true_bcb,
@ -183,9 +192,10 @@ fn create_mappings(
true_index: _,
false_index: _,
}| {
let source_region = region_for_span(span)?;
let true_term = term_for_bcb(true_bcb);
let false_term = term_for_bcb(false_bcb);
Mapping { kind: MappingKind::Branch { true_term, false_term }, span }
Some(Mapping { kind: MappingKind::Branch { true_term, false_term }, source_region })
},
));
@ -193,7 +203,7 @@ fn create_mappings(
let num_conditions = branches.len() as u16;
let conditions = branches
.into_iter()
.map(
.filter_map(
|&mappings::MCDCBranch {
span,
true_bcb,
@ -202,29 +212,31 @@ fn create_mappings(
true_index: _,
false_index: _,
}| {
let source_region = region_for_span(span)?;
let true_term = term_for_bcb(true_bcb);
let false_term = term_for_bcb(false_bcb);
Mapping {
Some(Mapping {
kind: MappingKind::MCDCBranch {
true_term,
false_term,
mcdc_params: condition_info,
},
span,
}
source_region,
})
},
)
.collect::<Vec<_>>();
if conditions.len() == num_conditions as usize {
if conditions.len() == num_conditions as usize
&& let Some(source_region) = region_for_span(decision.span)
{
// LLVM requires end index for counter mapping regions.
let kind = MappingKind::MCDCDecision(DecisionInfo {
bitmap_idx: (decision.bitmap_idx + decision.num_test_vectors) as u32,
num_conditions,
});
mappings.extend(
std::iter::once(Mapping { kind, span: decision.span })
.chain(conditions.into_iter()),
std::iter::once(Mapping { kind, source_region }).chain(conditions.into_iter()),
);
} else {
mappings.extend(conditions.into_iter().map(|mapping| {
@ -233,7 +245,10 @@ fn create_mappings(
else {
unreachable!("all mappings here are MCDCBranch as shown above");
};
Mapping { kind: MappingKind::Branch { true_term, false_term }, span: mapping.span }
Mapping {
kind: MappingKind::Branch { true_term, false_term },
source_region: mapping.source_region,
}
}))
}
}
@ -376,6 +391,121 @@ fn inject_statement(mir_body: &mut mir::Body<'_>, counter_kind: CoverageKind, bb
data.statements.insert(0, statement);
}
fn ensure_non_empty_span(
source_map: &SourceMap,
hir_info: &ExtractedHirInfo,
span: Span,
) -> Option<Span> {
if !span.is_empty() {
return Some(span);
}
let lo = span.lo();
let hi = span.hi();
// The span is empty, so try to expand it to cover an adjacent '{' or '}',
// but only within the bounds of the body span.
let try_next = hi < hir_info.body_span.hi();
let try_prev = hir_info.body_span.lo() < lo;
if !(try_next || try_prev) {
return None;
}
source_map
.span_to_source(span, |src, start, end| try {
// We're only checking for specific ASCII characters, so we don't
// have to worry about multi-byte code points.
if try_next && src.as_bytes()[end] == b'{' {
Some(span.with_hi(hi + BytePos(1)))
} else if try_prev && src.as_bytes()[start - 1] == b'}' {
Some(span.with_lo(lo - BytePos(1)))
} else {
None
}
})
.ok()?
}
/// Converts the span into its start line and column, and end line and column.
///
/// Line numbers and column numbers are 1-based. Unlike most column numbers emitted by
/// the compiler, these column numbers are denoted in **bytes**, because that's what
/// LLVM's `llvm-cov` tool expects to see in coverage maps.
///
/// Returns `None` if the conversion failed for some reason. This shouldn't happen,
/// but it's hard to rule out entirely (especially in the presence of complex macros
/// or other expansions), and if it does happen then skipping a span or function is
/// better than an ICE or `llvm-cov` failure that the user might have no way to avoid.
fn make_source_region(
source_map: &SourceMap,
hir_info: &ExtractedHirInfo,
file: &SourceFile,
span: Span,
) -> Option<SourceRegion> {
let span = ensure_non_empty_span(source_map, hir_info, span)?;
let lo = span.lo();
let hi = span.hi();
// Column numbers need to be in bytes, so we can't use the more convenient
// `SourceMap` methods for looking up file coordinates.
let line_and_byte_column = |pos: BytePos| -> Option<(usize, usize)> {
let rpos = file.relative_position(pos);
let line_index = file.lookup_line(rpos)?;
let line_start = file.lines()[line_index];
// Line numbers and column numbers are 1-based, so add 1 to each.
Some((line_index + 1, (rpos - line_start).to_usize() + 1))
};
let (mut start_line, start_col) = line_and_byte_column(lo)?;
let (mut end_line, end_col) = line_and_byte_column(hi)?;
// Apply an offset so that code in doctests has correct line numbers.
// FIXME(#79417): Currently we have no way to offset doctest _columns_.
start_line = source_map.doctest_offset_line(&file.name, start_line);
end_line = source_map.doctest_offset_line(&file.name, end_line);
check_source_region(SourceRegion {
start_line: start_line as u32,
start_col: start_col as u32,
end_line: end_line as u32,
end_col: end_col as u32,
})
}
/// If `llvm-cov` sees a source region that is improperly ordered (end < start),
/// it will immediately exit with a fatal error. To prevent that from happening,
/// discard regions that are improperly ordered, or might be interpreted in a
/// way that makes them improperly ordered.
fn check_source_region(source_region: SourceRegion) -> Option<SourceRegion> {
let SourceRegion { start_line, start_col, end_line, end_col } = source_region;
// Line/column coordinates are supposed to be 1-based. If we ever emit
// coordinates of 0, `llvm-cov` might misinterpret them.
let all_nonzero = [start_line, start_col, end_line, end_col].into_iter().all(|x| x != 0);
// Coverage mappings use the high bit of `end_col` to indicate that a
// region is actually a "gap" region, so make sure it's unset.
let end_col_has_high_bit_unset = (end_col & (1 << 31)) == 0;
// If a region is improperly ordered (end < start), `llvm-cov` will exit
// with a fatal error, which is inconvenient for users and hard to debug.
let is_ordered = (start_line, start_col) <= (end_line, end_col);
if all_nonzero && end_col_has_high_bit_unset && is_ordered {
Some(source_region)
} else {
debug!(
?source_region,
?all_nonzero,
?end_col_has_high_bit_unset,
?is_ordered,
"Skipping source region that would be misinterpreted or rejected by LLVM"
);
// If this happens in a debug build, ICE to make it easier to notice.
debug_assert!(false, "Improper source region: {source_region:?}");
None
}
}
/// Function information extracted from HIR by the coverage instrumentor.
#[derive(Debug)]
struct ExtractedHirInfo {