bjoernager/rust
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coverage: Remove unhelpful code for handling multiple files per function

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Functions currently can't have mappings in multiple files, and if that ever
changes (e.g. to properly support expansion regions), this code will need to be
completely overhauled anyway.
This commit is contained in:
Zalathar 2024-11-04 14:53:52 +11:00
parent 3f9c54caf0
commit 996bdabc2a
11 changed files with 96 additions and 108 deletions
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2
compiler/rustc_codegen_llvm/src/coverageinfo/ffi.rs
View file

@ -138,7 +138,7 @@ pub(crate) struct CoverageSpan {
impl CoverageSpan {
pub(crate) fn from_source_region(file_id: u32, code_region: &SourceRegion) -> Self {
let &SourceRegion { file_name: _, start_line, start_col, end_line, end_col } = code_region;
let &SourceRegion { start_line, start_col, end_line, end_col } = code_region;
// Internally, LLVM uses the high bit of `end_col` to distinguish between
// code regions and gap regions, so it can't be used by the column number.
assert!(end_col & (1u32 << 31) == 0, "high bit of `end_col` must be unset: {end_col:#X}");

8
compiler/rustc_codegen_llvm/src/coverageinfo/map_data.rs
View file

@ -6,7 +6,6 @@ use rustc_middle::mir::coverage::{
SourceRegion,
};
use rustc_middle::ty::Instance;
use rustc_span::Symbol;
use tracing::{debug, instrument};
use crate::coverageinfo::ffi::{Counter, CounterExpression, ExprKind};
@ -180,7 +179,7 @@ impl<'tcx> FunctionCoverageCollector<'tcx> {
}
pub(crate) struct FunctionCoverage<'tcx> {
function_coverage_info: &'tcx FunctionCoverageInfo,
pub(crate) function_coverage_info: &'tcx FunctionCoverageInfo,
is_used: bool,
counters_seen: BitSet<CounterId>,
@ -199,11 +198,6 @@ impl<'tcx> FunctionCoverage<'tcx> {
if self.is_used { self.function_coverage_info.function_source_hash } else { 0 }
}
/// Returns an iterator over all filenames used by this function's mappings.
pub(crate) fn all_file_names(&self) -> impl Iterator<Item = Symbol> + Captures<'_> {
self.function_coverage_info.mappings.iter().map(|mapping| mapping.source_region.file_name)
}
/// Convert this function's coverage expression data into a form that can be
/// passed through FFI to LLVM.
pub(crate) fn counter_expressions(

102
compiler/rustc_codegen_llvm/src/coverageinfo/mapgen.rs
View file

@ -11,8 +11,10 @@ use rustc_index::IndexVec;
use rustc_middle::mir::coverage::MappingKind;
use rustc_middle::ty::{self, TyCtxt};
use rustc_middle::{bug, mir};
use rustc_span::Symbol;
use rustc_session::RemapFileNameExt;
use rustc_session::config::RemapPathScopeComponents;
use rustc_span::def_id::DefIdSet;
use rustc_span::{Span, Symbol};
use rustc_target::spec::HasTargetSpec;
use tracing::debug;
@ -69,8 +71,10 @@ pub(crate) fn finalize(cx: &CodegenCx<'_, '_>) {
.map(|(instance, function_coverage)| (instance, function_coverage.into_finished()))
.collect::<Vec<_>>();
let all_file_names =
function_coverage_entries.iter().flat_map(|(_, fn_cov)| fn_cov.all_file_names());
let all_file_names = function_coverage_entries
.iter()
.map(|(_, fn_cov)| fn_cov.function_coverage_info.body_span)
.map(|span| span_file_name(tcx, span));
let global_file_table = GlobalFileTable::new(all_file_names);
// Encode all filenames referenced by coverage mappings in this CGU.
@ -95,7 +99,7 @@ pub(crate) fn finalize(cx: &CodegenCx<'_, '_>) {
let is_used = function_coverage.is_used();
let coverage_mapping_buffer =
encode_mappings_for_function(&global_file_table, &function_coverage);
encode_mappings_for_function(tcx, &global_file_table, &function_coverage);
if coverage_mapping_buffer.is_empty() {
if function_coverage.is_used() {
@ -232,12 +236,20 @@ impl VirtualFileMapping {
}
}
fn span_file_name(tcx: TyCtxt<'_>, span: Span) -> Symbol {
let source_file = tcx.sess.source_map().lookup_source_file(span.lo());
let name =
source_file.name.for_scope(tcx.sess, RemapPathScopeComponents::MACRO).to_string_lossy();
Symbol::intern(&name)
}
/// Using the expressions and counter regions collected for a single function,
/// generate the variable-sized payload of its corresponding `__llvm_covfun`
/// entry. The payload is returned as a vector of bytes.
///
/// Newly-encountered filenames will be added to the global file table.
fn encode_mappings_for_function(
tcx: TyCtxt<'_>,
global_file_table: &GlobalFileTable,
function_coverage: &FunctionCoverage<'_>,
) -> Vec<u8> {
@ -254,53 +266,45 @@ fn encode_mappings_for_function(
let mut mcdc_branch_regions = vec![];
let mut mcdc_decision_regions = vec![];
// Group mappings into runs with the same filename, preserving the order
// yielded by `FunctionCoverage`.
// Prepare file IDs for each filename, and prepare the mapping data so that
// we can pass it through FFI to LLVM.
for (file_name, counter_regions_for_file) in
&counter_regions.group_by(|(_, region)| region.file_name)
{
// Look up the global file ID for this filename.
let global_file_id = global_file_table.global_file_id_for_file_name(file_name);
// Currently a function's mappings must all be in the same file as its body span.
let file_name = span_file_name(tcx, function_coverage.function_coverage_info.body_span);
// Associate that global file ID with a local file ID for this function.
let local_file_id = virtual_file_mapping.local_id_for_global(global_file_id);
debug!(" file id: {local_file_id:?} => {global_file_id:?} = '{file_name:?}'");
// Look up the global file ID for that filename.
let global_file_id = global_file_table.global_file_id_for_file_name(file_name);
// For each counter/region pair in this function+file, convert it to a
// form suitable for FFI.
for (mapping_kind, region) in counter_regions_for_file {
debug!("Adding counter {mapping_kind:?} to map for {region:?}");
let span = ffi::CoverageSpan::from_source_region(local_file_id.as_u32(), region);
match mapping_kind {
MappingKind::Code(term) => {
code_regions
.push(ffi::CodeRegion { span, counter: ffi::Counter::from_term(term) });
}
MappingKind::Branch { true_term, false_term } => {
branch_regions.push(ffi::BranchRegion {
span,
true_counter: ffi::Counter::from_term(true_term),
false_counter: ffi::Counter::from_term(false_term),
});
}
MappingKind::MCDCBranch { true_term, false_term, mcdc_params } => {
mcdc_branch_regions.push(ffi::MCDCBranchRegion {
span,
true_counter: ffi::Counter::from_term(true_term),
false_counter: ffi::Counter::from_term(false_term),
mcdc_branch_params: ffi::mcdc::BranchParameters::from(mcdc_params),
});
}
MappingKind::MCDCDecision(mcdc_decision_params) => {
mcdc_decision_regions.push(ffi::MCDCDecisionRegion {
span,
mcdc_decision_params: ffi::mcdc::DecisionParameters::from(
mcdc_decision_params,
),
});
}
// Associate that global file ID with a local file ID for this function.
let local_file_id = virtual_file_mapping.local_id_for_global(global_file_id);
debug!(" file id: {local_file_id:?} => {global_file_id:?} = '{file_name:?}'");
// For each counter/region pair in this function+file, convert it to a
// form suitable for FFI.
for (mapping_kind, region) in counter_regions {
debug!("Adding counter {mapping_kind:?} to map for {region:?}");
let span = ffi::CoverageSpan::from_source_region(local_file_id.as_u32(), region);
match mapping_kind {
MappingKind::Code(term) => {
code_regions.push(ffi::CodeRegion { span, counter: ffi::Counter::from_term(term) });
}
MappingKind::Branch { true_term, false_term } => {
branch_regions.push(ffi::BranchRegion {
span,
true_counter: ffi::Counter::from_term(true_term),
false_counter: ffi::Counter::from_term(false_term),
});
}
MappingKind::MCDCBranch { true_term, false_term, mcdc_params } => {
mcdc_branch_regions.push(ffi::MCDCBranchRegion {
span,
true_counter: ffi::Counter::from_term(true_term),
false_counter: ffi::Counter::from_term(false_term),
mcdc_branch_params: ffi::mcdc::BranchParameters::from(mcdc_params),
});
}
MappingKind::MCDCDecision(mcdc_decision_params) => {
mcdc_decision_regions.push(ffi::MCDCDecisionRegion {
span,
mcdc_decision_params: ffi::mcdc::DecisionParameters::from(mcdc_decision_params),
});
}
}
}