diff options
Diffstat (limited to 'compiler/rustc_codegen_llvm/src')
5 files changed, 156 insertions, 37 deletions
diff --git a/compiler/rustc_codegen_llvm/src/coverageinfo/ffi.rs b/compiler/rustc_codegen_llvm/src/coverageinfo/ffi.rs index 7aa03908f0f..19d6726002c 100644 --- a/compiler/rustc_codegen_llvm/src/coverageinfo/ffi.rs +++ b/compiler/rustc_codegen_llvm/src/coverageinfo/ffi.rs @@ -1,6 +1,4 @@ -use rustc_middle::mir::coverage::{CounterId, CovTerm, ExpressionId, SourceRegion}; - -use crate::coverageinfo::mapgen::LocalFileId; +use rustc_middle::mir::coverage::{CounterId, CovTerm, ExpressionId}; /// Must match the layout of `LLVMRustCounterKind`. #[derive(Copy, Clone, Debug)] @@ -126,30 +124,16 @@ 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. - file_id: u32, + pub(crate) file_id: u32, /// 1-based starting line of the source code span. - start_line: u32, + pub(crate) start_line: u32, /// 1-based starting column of the source code span. - start_col: u32, + pub(crate) start_col: u32, /// 1-based ending line of the source code span. - end_line: u32, + pub(crate) end_line: u32, /// 1-based ending column of the source code span. High bit must be unset. - 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 } - } + pub(crate) end_col: u32, } /// Must match the layout of `LLVMRustCoverageCodeRegion`. diff --git a/compiler/rustc_codegen_llvm/src/coverageinfo/map_data.rs b/compiler/rustc_codegen_llvm/src/coverageinfo/map_data.rs index e3c0df27883..95746b88ced 100644 --- a/compiler/rustc_codegen_llvm/src/coverageinfo/map_data.rs +++ b/compiler/rustc_codegen_llvm/src/coverageinfo/map_data.rs @@ -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> { }) } - /// 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( + /// Yields all this function's coverage mappings, after simplifying away + /// unused counters and counter expressions. + pub(crate) fn mapping_spans( &self, - ) -> impl Iterator<Item = (MappingKind, &SourceRegion)> + ExactSizeIterator { + ) -> impl Iterator<Item = (MappingKind, Span)> + ExactSizeIterator + Captures<'_> { self.function_coverage_info.mappings.iter().map(move |mapping| { - let Mapping { kind, source_region } = mapping; + let &Mapping { ref kind, span } = mapping; let kind = kind.map_terms(|term| if self.is_zero_term(term) { CovTerm::Zero } else { term }); - (kind, source_region) + (kind, span) }) } diff --git a/compiler/rustc_codegen_llvm/src/coverageinfo/mapgen.rs b/compiler/rustc_codegen_llvm/src/coverageinfo/mapgen.rs index 0c79cd5c262..e8dfed1f06a 100644 --- a/compiler/rustc_codegen_llvm/src/coverageinfo/mapgen.rs +++ b/compiler/rustc_codegen_llvm/src/coverageinfo/mapgen.rs @@ -1,3 +1,5 @@ +mod spans; + use std::ffi::CString; use std::iter; @@ -201,7 +203,7 @@ 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. - pub(crate) struct LocalFileId {} + struct LocalFileId {} } /// Holds a mapping from "local" (per-function) file IDs to "global" (per-CGU) @@ -244,11 +246,13 @@ fn encode_mappings_for_function( global_file_table: &GlobalFileTable, function_coverage: &FunctionCoverage<'_>, ) -> Vec<u8> { - let counter_regions = function_coverage.counter_regions(); - if counter_regions.is_empty() { + let mapping_spans = function_coverage.mapping_spans(); + if mapping_spans.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(); @@ -258,7 +262,9 @@ 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 file_name = span_file_name(tcx, function_coverage.function_coverage_info.body_span); + let file_name = span_file_name(tcx, fn_cov_info.body_span); + let source_map = tcx.sess.source_map(); + let source_file = source_map.lookup_source_file(fn_cov_info.body_span.lo()); // Look up the global file ID for that filename. let global_file_id = global_file_table.global_file_id_for_file_name(file_name); @@ -267,11 +273,15 @@ fn encode_mappings_for_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 + 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 // form suitable for FFI. - for (mapping_kind, region) in counter_regions { - debug!("Adding counter {mapping_kind:?} to map for {region:?}"); - let cov_span = ffi::CoverageSpan::from_source_region(local_file_id, region); + 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 }; match mapping_kind { MappingKind::Code(term) => { code_regions diff --git a/compiler/rustc_codegen_llvm/src/coverageinfo/mapgen/spans.rs b/compiler/rustc_codegen_llvm/src/coverageinfo/mapgen/spans.rs new file mode 100644 index 00000000000..4a7721879fd --- /dev/null +++ b/compiler/rustc_codegen_llvm/src/coverageinfo/mapgen/spans.rs @@ -0,0 +1,124 @@ +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 + } +} diff --git a/compiler/rustc_codegen_llvm/src/lib.rs b/compiler/rustc_codegen_llvm/src/lib.rs index 3dfb86d422d..9f398107fc6 100644 --- a/compiler/rustc_codegen_llvm/src/lib.rs +++ b/compiler/rustc_codegen_llvm/src/lib.rs @@ -17,6 +17,7 @@ #![feature(iter_intersperse)] #![feature(let_chains)] #![feature(rustdoc_internals)] +#![feature(try_blocks)] #![warn(unreachable_pub)] // tidy-alphabetical-end |