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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
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36
compiler/rustc_codegen_llvm/src/coverageinfo/ffi.rs
View file

@ -1,4 +1,6 @@
use rustc_middle::mir::coverage::{CounterId, CovTerm, ExpressionId};
use rustc_middle::mir::coverage::{CounterId, CovTerm, ExpressionId, SourceRegion};
use crate::coverageinfo::mapgen::LocalFileId;
/// Must match the layout of `LLVMRustCounterKind`.
#[derive(Copy, Clone, Debug)]
@ -124,23 +126,37 @@ pub(crate) struct CoverageSpan {
/// Local index into the function's local-to-global file ID table.
/// The value at that index is itself an index into the coverage filename
/// table in the CGU's `__llvm_covmap` section.
pub(crate) file_id: u32,
file_id: u32,
/// 1-based starting line of the source code span.
pub(crate) start_line: u32,
start_line: u32,
/// 1-based starting column of the source code span.
pub(crate) start_col: u32,
start_col: u32,
/// 1-based ending line of the source code span.
pub(crate) end_line: u32,
end_line: u32,
/// 1-based ending column of the source code span. High bit must be unset.
pub(crate) end_col: u32,
end_col: u32,
}
impl CoverageSpan {
pub(crate) fn from_source_region(
local_file_id: LocalFileId,
code_region: &SourceRegion,
) -> Self {
let file_id = local_file_id.as_u32();
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}");
Self { file_id, start_line, start_col, end_line, end_col }
}
}
/// Must match the layout of `LLVMRustCoverageCodeRegion`.
#[derive(Clone, Debug)]
#[repr(C)]
pub(crate) struct CodeRegion {
pub(crate) cov_span: CoverageSpan,
pub(crate) span: CoverageSpan,
pub(crate) counter: Counter,
}
@ -148,7 +164,7 @@ pub(crate) struct CodeRegion {
#[derive(Clone, Debug)]
#[repr(C)]
pub(crate) struct BranchRegion {
pub(crate) cov_span: CoverageSpan,
pub(crate) span: CoverageSpan,
pub(crate) true_counter: Counter,
pub(crate) false_counter: Counter,
}
@ -157,7 +173,7 @@ pub(crate) struct BranchRegion {
#[derive(Clone, Debug)]
#[repr(C)]
pub(crate) struct MCDCBranchRegion {
pub(crate) cov_span: CoverageSpan,
pub(crate) span: CoverageSpan,
pub(crate) true_counter: Counter,
pub(crate) false_counter: Counter,
pub(crate) mcdc_branch_params: mcdc::BranchParameters,
@ -167,6 +183,6 @@ pub(crate) struct MCDCBranchRegion {
#[derive(Clone, Debug)]
#[repr(C)]
pub(crate) struct MCDCDecisionRegion {
pub(crate) cov_span: CoverageSpan,
pub(crate) span: CoverageSpan,
pub(crate) mcdc_decision_params: mcdc::DecisionParameters,
}

14
compiler/rustc_codegen_llvm/src/coverageinfo/map_data.rs
View file

@ -3,9 +3,9 @@ use rustc_data_structures::fx::FxIndexSet;
use rustc_index::bit_set::BitSet;
use rustc_middle::mir::coverage::{
CounterId, CovTerm, Expression, ExpressionId, FunctionCoverageInfo, Mapping, MappingKind, Op,
SourceRegion,
};
use rustc_middle::ty::Instance;
use rustc_span::Span;
use tracing::{debug, instrument};
use crate::coverageinfo::ffi::{Counter, CounterExpression, ExprKind};
@ -220,16 +220,16 @@ impl<'tcx> FunctionCoverage<'tcx> {
})
}
/// Yields all this function's coverage mappings, after simplifying away
/// unused counters and counter expressions.
pub(crate) fn mapping_spans(
/// Converts this function's coverage mappings into an intermediate form
/// that will be used by `mapgen` when preparing for FFI.
pub(crate) fn counter_regions(
&self,
) -> impl Iterator<Item = (MappingKind, Span)> + ExactSizeIterator + Captures<'_> {
) -> impl Iterator<Item = (MappingKind, &SourceRegion)> + ExactSizeIterator {
self.function_coverage_info.mappings.iter().map(move |mapping| {
let &Mapping { ref kind, span } = mapping;
let Mapping { kind, source_region } = mapping;
let kind =
kind.map_terms(|term| if self.is_zero_term(term) { CovTerm::Zero } else { term });
(kind, span)
(kind, source_region)
})
}

127
compiler/rustc_codegen_llvm/src/coverageinfo/mapgen.rs
View file

@ -1,14 +1,12 @@
mod spans;
use std::ffi::CString;
use std::sync::Arc;
use std::iter;
use itertools::Itertools as _;
use rustc_abi::Align;
use rustc_codegen_ssa::traits::{
BaseTypeCodegenMethods, ConstCodegenMethods, StaticCodegenMethods,
};
use rustc_data_structures::fx::{FxHashSet, FxIndexMap};
use rustc_data_structures::fx::{FxHashSet, FxIndexMap, FxIndexSet};
use rustc_hir::def_id::{DefId, LocalDefId};
use rustc_index::IndexVec;
use rustc_middle::mir::coverage::MappingKind;
@ -17,7 +15,7 @@ use rustc_middle::{bug, mir};
use rustc_session::RemapFileNameExt;
use rustc_session::config::RemapPathScopeComponents;
use rustc_span::def_id::DefIdSet;
use rustc_span::{SourceFile, StableSourceFileId};
use rustc_span::{Span, Symbol};
use rustc_target::spec::HasTargetSpec;
use tracing::debug;
@ -74,11 +72,11 @@ pub(crate) fn finalize(cx: &CodegenCx<'_, '_>) {
.map(|(instance, function_coverage)| (instance, function_coverage.into_finished()))
.collect::<Vec<_>>();
let all_files = function_coverage_entries
let all_file_names = function_coverage_entries
.iter()
.map(|(_, fn_cov)| fn_cov.function_coverage_info.body_span)
.map(|span| tcx.sess.source_map().lookup_source_file(span.lo()));
let global_file_table = GlobalFileTable::new(all_files);
.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.
let filenames_buffer = global_file_table.make_filenames_buffer(tcx);
@ -105,8 +103,15 @@ pub(crate) fn finalize(cx: &CodegenCx<'_, '_>) {
encode_mappings_for_function(tcx, &global_file_table, &function_coverage);
if coverage_mapping_buffer.is_empty() {
debug!("function has no mappings to embed; skipping");
continue;
if function_coverage.is_used() {
bug!(
"A used function should have had coverage mapping data but did not: {}",
mangled_function_name
);
} else {
debug!("unused function had no coverage mapping data: {}", mangled_function_name);
continue;
}
}
if !is_used {
@ -143,34 +148,29 @@ pub(crate) fn finalize(cx: &CodegenCx<'_, '_>) {
}
}
/// Maps "global" (per-CGU) file ID numbers to their underlying source files.
/// Maps "global" (per-CGU) file ID numbers to their underlying filenames.
struct GlobalFileTable {
/// This "raw" table doesn't include the working dir, so a file's
/// This "raw" table doesn't include the working dir, so a filename's
/// global ID is its index in this set **plus one**.
raw_file_table: FxIndexMap<StableSourceFileId, Arc<SourceFile>>,
raw_file_table: FxIndexSet<Symbol>,
}
impl GlobalFileTable {
fn new(all_files: impl IntoIterator<Item = Arc<SourceFile>>) -> Self {
// Collect all of the files into a set. Files usually come in contiguous
// runs, so we can dedup adjacent ones to save work.
let mut raw_file_table = all_files
.into_iter()
.dedup_by(|a, b| a.stable_id == b.stable_id)
.map(|f| (f.stable_id, f))
.collect::<FxIndexMap<StableSourceFileId, Arc<SourceFile>>>();
fn new(all_file_names: impl IntoIterator<Item = Symbol>) -> Self {
// Collect all of the filenames into a set. Filenames usually come in
// contiguous runs, so we can dedup adjacent ones to save work.
let mut raw_file_table = all_file_names.into_iter().dedup().collect::<FxIndexSet<Symbol>>();
// Sort the file table by its underlying filenames.
raw_file_table.sort_unstable_by(|_, a, _, b| {
Ord::cmp(&a.name, &b.name).then_with(|| Ord::cmp(&a.stable_id, &b.stable_id))
});
// Sort the file table by its actual string values, not the arbitrary
// ordering of its symbols.
raw_file_table.sort_unstable_by(|a, b| a.as_str().cmp(b.as_str()));
Self { raw_file_table }
}
fn global_file_id_for_file(&self, file: &SourceFile) -> GlobalFileId {
let raw_id = self.raw_file_table.get_index_of(&file.stable_id).unwrap_or_else(|| {
bug!("file not found in prepared global file table: {:?}", file.name);
fn global_file_id_for_file_name(&self, file_name: Symbol) -> GlobalFileId {
let raw_id = self.raw_file_table.get_index_of(&file_name).unwrap_or_else(|| {
bug!("file name not found in prepared global file table: {file_name}");
});
// The raw file table doesn't include an entry for the working dir
// (which has ID 0), so add 1 to get the correct ID.
@ -178,27 +178,24 @@ impl GlobalFileTable {
}
fn make_filenames_buffer(&self, tcx: TyCtxt<'_>) -> Vec<u8> {
let mut table = Vec::with_capacity(self.raw_file_table.len() + 1);
// LLVM Coverage Mapping Format version 6 (zero-based encoded as 5)
// requires setting the first filename to the compilation directory.
// Since rustc generates coverage maps with relative paths, the
// compilation directory can be combined with the relative paths
// to get absolute paths, if needed.
table.push(
tcx.sess
.opts
.working_dir
.for_scope(tcx.sess, RemapPathScopeComponents::MACRO)
.to_string_lossy(),
);
use rustc_session::RemapFileNameExt;
use rustc_session::config::RemapPathScopeComponents;
let working_dir: &str = &tcx
.sess
.opts
.working_dir
.for_scope(tcx.sess, RemapPathScopeComponents::MACRO)
.to_string_lossy();
// Add the regular entries after the base directory.
table.extend(self.raw_file_table.values().map(|file| {
file.name.for_scope(tcx.sess, RemapPathScopeComponents::MACRO).to_string_lossy()
}));
llvm_cov::write_filenames_to_buffer(table.iter().map(|f| f.as_ref()))
// Insert the working dir at index 0, before the other filenames.
let filenames =
iter::once(working_dir).chain(self.raw_file_table.iter().map(Symbol::as_str));
llvm_cov::write_filenames_to_buffer(filenames)
}
}
@ -211,7 +208,7 @@ rustc_index::newtype_index! {
/// An index into a function's list of global file IDs. That underlying list
/// of local-to-global mappings will be embedded in the function's record in
/// the `__llvm_covfun` linker section.
struct LocalFileId {}
pub(crate) struct LocalFileId {}
}
/// Holds a mapping from "local" (per-function) file IDs to "global" (per-CGU)
@ -237,6 +234,13 @@ 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.
@ -247,13 +251,11 @@ fn encode_mappings_for_function(
global_file_table: &GlobalFileTable,
function_coverage: &FunctionCoverage<'_>,
) -> Vec<u8> {
let mapping_spans = function_coverage.mapping_spans();
if mapping_spans.is_empty() {
let counter_regions = function_coverage.counter_regions();
if counter_regions.is_empty() {
return Vec::new();
}
let fn_cov_info = function_coverage.function_coverage_info;
let expressions = function_coverage.counter_expressions().collect::<Vec<_>>();
let mut virtual_file_mapping = VirtualFileMapping::default();
@ -263,39 +265,34 @@ fn encode_mappings_for_function(
let mut mcdc_decision_regions = vec![];
// Currently a function's mappings must all be in the same file as its body span.
let source_map = tcx.sess.source_map();
let source_file = source_map.lookup_source_file(fn_cov_info.body_span.lo());
let file_name = span_file_name(tcx, function_coverage.function_coverage_info.body_span);
// Look up the global file ID for that file.
let global_file_id = global_file_table.global_file_id_for_file(&source_file);
// Look up the global file ID for that filename.
let global_file_id = global_file_table.global_file_id_for_file_name(file_name);
// 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:?}'");
let make_cov_span = |span| {
spans::make_coverage_span(local_file_id, source_map, fn_cov_info, &source_file, span)
};
// For each coverage mapping span in this function+file, convert it to a
// For each counter/region pair in this function+file, convert it to a
// form suitable for FFI.
for (mapping_kind, span) in mapping_spans {
debug!("Adding counter {mapping_kind:?} to map for {span:?}");
let Some(cov_span) = make_cov_span(span) else { continue };
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, region);
match mapping_kind {
MappingKind::Code(term) => {
code_regions
.push(ffi::CodeRegion { cov_span, counter: ffi::Counter::from_term(term) });
code_regions.push(ffi::CodeRegion { span, counter: ffi::Counter::from_term(term) });
}
MappingKind::Branch { true_term, false_term } => {
branch_regions.push(ffi::BranchRegion {
cov_span,
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 {
cov_span,
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),
@ -303,7 +300,7 @@ fn encode_mappings_for_function(
}
MappingKind::MCDCDecision(mcdc_decision_params) => {
mcdc_decision_regions.push(ffi::MCDCDecisionRegion {
cov_span,
span,
mcdc_decision_params: ffi::mcdc::DecisionParameters::from(mcdc_decision_params),
});
}

124
compiler/rustc_codegen_llvm/src/coverageinfo/mapgen/spans.rs
View file

@ -1,124 +0,0 @@
use rustc_middle::mir::coverage::FunctionCoverageInfo;
use rustc_span::source_map::SourceMap;
use rustc_span::{BytePos, Pos, SourceFile, Span};
use tracing::debug;
use crate::coverageinfo::ffi;
use crate::coverageinfo::mapgen::LocalFileId;
/// 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.
pub(crate) fn make_coverage_span(
file_id: LocalFileId,
source_map: &SourceMap,
fn_cov_info: &FunctionCoverageInfo,
file: &SourceFile,
span: Span,
) -> Option<ffi::CoverageSpan> {
let span = ensure_non_empty_span(source_map, fn_cov_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_coverage_span(ffi::CoverageSpan {
file_id: file_id.as_u32(),
start_line: start_line as u32,
start_col: start_col as u32,
end_line: end_line as u32,
end_col: end_col as u32,
})
}
fn ensure_non_empty_span(
source_map: &SourceMap,
fn_cov_info: &FunctionCoverageInfo,
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 < fn_cov_info.body_span.hi();
let try_prev = fn_cov_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()?
}
/// 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_coverage_span(cov_span: ffi::CoverageSpan) -> Option<ffi::CoverageSpan> {
let ffi::CoverageSpan { file_id: _, start_line, start_col, end_line, end_col } = cov_span;
// 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(cov_span)
} else {
debug!(
?cov_span,
?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: {cov_span:?}");
None
}
}

1
compiler/rustc_codegen_llvm/src/lib.rs
View file

@ -17,7 +17,6 @@
#![feature(iter_intersperse)]
#![feature(let_chains)]
#![feature(rustdoc_internals)]
#![feature(try_blocks)]
#![warn(unreachable_pub)]
// tidy-alphabetical-end