diff options
Diffstat (limited to 'compiler/rustc_codegen_llvm/src')
| -rw-r--r-- | compiler/rustc_codegen_llvm/src/coverageinfo/mapgen.rs | 120 |
1 files changed, 34 insertions, 86 deletions
diff --git a/compiler/rustc_codegen_llvm/src/coverageinfo/mapgen.rs b/compiler/rustc_codegen_llvm/src/coverageinfo/mapgen.rs index e0af5653753..32f18419753 100644 --- a/compiler/rustc_codegen_llvm/src/coverageinfo/mapgen.rs +++ b/compiler/rustc_codegen_llvm/src/coverageinfo/mapgen.rs @@ -5,12 +5,13 @@ use crate::llvm; use llvm::coverageinfo::CounterMappingRegion; use rustc_codegen_ssa::coverageinfo::map::{Counter, CounterExpression}; use rustc_codegen_ssa::traits::{ConstMethods, CoverageInfoMethods}; -use rustc_data_structures::fx::{FxHashMap, FxHashSet, FxIndexSet}; -use rustc_hir::def_id::{DefId, DefIdSet}; +use rustc_data_structures::fx::FxIndexSet; +use rustc_hir::def::DefKind; +use rustc_hir::def_id::DefIdSet; use rustc_llvm::RustString; +use rustc_middle::middle::codegen_fn_attrs::CodegenFnAttrFlags; use rustc_middle::mir::coverage::CodeRegion; use rustc_middle::ty::TyCtxt; -use rustc_span::Symbol; use std::ffi::CString; @@ -46,7 +47,7 @@ pub fn finalize<'ll, 'tcx>(cx: &CodegenCx<'ll, 'tcx>) { // functions exist. Generate synthetic functions with a (required) single counter, and add the // MIR `Coverage` code regions to the `function_coverage_map`, before calling // `ctx.take_function_coverage_map()`. - if !tcx.sess.instrument_coverage_except_unused_functions() { + if cx.codegen_unit.is_code_coverage_dead_code_cgu() { add_unused_functions(cx); } @@ -271,26 +272,35 @@ fn save_function_record( /// `DefId`s (`tcx` query `mir_keys`) minus the codegenned `DefId`s (`tcx` query /// `codegened_and_inlined_items`). /// -/// *HOWEVER* the codegenned `DefId`s are partitioned across multiple `CodegenUnit`s (CGUs), and -/// this function is processing a `function_coverage_map` for the functions (`Instance`/`DefId`) -/// allocated to only one of those CGUs. We must NOT inject any unused functions's `CodeRegion`s -/// more than once, so we have to pick a CGUs `function_coverage_map` into which the unused -/// function will be inserted. +/// These unused functions are then codegen'd in one of the CGUs which is marked as the +/// "code coverage dead code cgu" during the partitioning process. This prevents us from generating +/// code regions for the same function more than once which can lead to linker errors regarding +/// duplicate symbols. fn add_unused_functions<'ll, 'tcx>(cx: &CodegenCx<'ll, 'tcx>) { - let tcx = cx.tcx; + assert!(cx.codegen_unit.is_code_coverage_dead_code_cgu()); - // FIXME(#79622): Can this solution be simplified and/or improved? Are there other sources - // of compiler state data that might help (or better sources that could be exposed, but - // aren't yet)? + let tcx = cx.tcx; let ignore_unused_generics = tcx.sess.instrument_coverage_except_unused_generics(); - let all_def_ids: DefIdSet = tcx + let eligible_def_ids: DefIdSet = tcx .mir_keys(()) .iter() .filter_map(|local_def_id| { let def_id = local_def_id.to_def_id(); - if ignore_unused_generics && tcx.generics_of(def_id).requires_monomorphization(tcx) { + let kind = tcx.def_kind(def_id); + // `mir_keys` will give us `DefId`s for all kinds of things, not + // just "functions", like consts, statics, etc. Filter those out. + // If `ignore_unused_generics` was specified, filter out any + // generic functions from consideration as well. + if !matches!( + kind, + DefKind::Fn | DefKind::AssocFn | DefKind::Closure | DefKind::Generator + ) { + return None; + } else if ignore_unused_generics + && tcx.generics_of(def_id).requires_monomorphization(tcx) + { return None; } Some(local_def_id.to_def_id()) @@ -299,79 +309,17 @@ fn add_unused_functions<'ll, 'tcx>(cx: &CodegenCx<'ll, 'tcx>) { let codegenned_def_ids = tcx.codegened_and_inlined_items(()); - let mut unused_def_ids_by_file: FxHashMap<Symbol, Vec<DefId>> = FxHashMap::default(); - for &non_codegenned_def_id in all_def_ids.difference(codegenned_def_ids) { - // Make sure the non-codegenned (unused) function has at least one MIR - // `Coverage` statement with a code region, and return its file name. - if let Some(non_codegenned_file_name) = tcx.covered_file_name(non_codegenned_def_id) { - let def_ids = - unused_def_ids_by_file.entry(*non_codegenned_file_name).or_insert_with(Vec::new); - def_ids.push(non_codegenned_def_id); - } - } + for &non_codegenned_def_id in eligible_def_ids.difference(codegenned_def_ids) { + let codegen_fn_attrs = tcx.codegen_fn_attrs(non_codegenned_def_id); - if unused_def_ids_by_file.is_empty() { - // There are no unused functions with file names to add (in any CGU) - return; - } - - // Each `CodegenUnit` (CGU) has its own function_coverage_map, and generates a specific binary - // with its own coverage map. - // - // Each covered function `Instance` can be included in only one coverage map, produced from a - // specific function_coverage_map, from a specific CGU. - // - // Since unused functions did not generate code, they are not associated with any CGU yet. - // - // To avoid injecting the unused functions in multiple coverage maps (for multiple CGUs) - // determine which function_coverage_map has the responsibility for publishing unreachable - // coverage, based on file name: For each unused function, find the CGU that generates the - // first function (based on sorted `DefId`) from the same file. - // - // Add a new `FunctionCoverage` to the `function_coverage_map`, with unreachable code regions - // for each region in it's MIR. - - // Convert the `HashSet` of `codegenned_def_ids` to a sortable vector, and sort them. - let mut sorted_codegenned_def_ids: Vec<DefId> = codegenned_def_ids.iter().copied().collect(); - sorted_codegenned_def_ids.sort_unstable(); - - let mut first_covered_def_id_by_file: FxHashMap<Symbol, DefId> = FxHashMap::default(); - for &def_id in sorted_codegenned_def_ids.iter() { - if let Some(covered_file_name) = tcx.covered_file_name(def_id) { - // Only add files known to have unused functions - if unused_def_ids_by_file.contains_key(covered_file_name) { - first_covered_def_id_by_file.entry(*covered_file_name).or_insert(def_id); - } + // If a function is marked `#[no_coverage]`, then skip generating a + // dead code stub for it. + if codegen_fn_attrs.flags.contains(CodegenFnAttrFlags::NO_COVERAGE) { + debug!("skipping unused fn marked #[no_coverage]: {:?}", non_codegenned_def_id); + continue; } - } - - // Get the set of def_ids with coverage regions, known by *this* CoverageContext. - let cgu_covered_def_ids: DefIdSet = match cx.coverage_context() { - Some(ctx) => ctx - .function_coverage_map - .borrow() - .keys() - .map(|&instance| instance.def.def_id()) - .collect(), - None => return, - }; - let cgu_covered_files: FxHashSet<Symbol> = first_covered_def_id_by_file - .iter() - .filter_map( - |(&file_name, def_id)| { - if cgu_covered_def_ids.contains(def_id) { Some(file_name) } else { None } - }, - ) - .collect(); - - // For each file for which this CGU is responsible for adding unused function coverage, - // get the `def_id`s for each unused function (if any), define a synthetic function with a - // single LLVM coverage counter, and add the function's coverage `CodeRegion`s. to the - // function_coverage_map. - for covered_file_name in cgu_covered_files { - for def_id in unused_def_ids_by_file.remove(&covered_file_name).into_iter().flatten() { - cx.define_unused_fn(def_id); - } + debug!("generating unused fn: {:?}", non_codegenned_def_id); + cx.define_unused_fn(non_codegenned_def_id); } } |