diff --git a/compiler/rustc_codegen_llvm/src/coverageinfo/map_data.rs b/compiler/rustc_codegen_llvm/src/coverageinfo/map_data.rs deleted file mode 100644 index 8b464b405629..000000000000 --- a/compiler/rustc_codegen_llvm/src/coverageinfo/map_data.rs +++ /dev/null @@ -1,24 +0,0 @@ -use rustc_middle::mir::coverage::{CoverageIdsInfo, FunctionCoverageInfo}; - -pub(crate) struct FunctionCoverage<'tcx> { - /// If `None`, the corresponding function is unused. - ids_info: Option<&'tcx CoverageIdsInfo>, -} - -impl<'tcx> FunctionCoverage<'tcx> { - pub(crate) fn new_used( - _function_coverage_info: &'tcx FunctionCoverageInfo, - ids_info: &'tcx CoverageIdsInfo, - ) -> Self { - Self { ids_info: Some(ids_info) } - } - - pub(crate) fn new_unused(_function_coverage_info: &'tcx FunctionCoverageInfo) -> Self { - Self { ids_info: None } - } - - /// Returns true for a used (called) function, and false for an unused function. - pub(crate) fn is_used(&self) -> bool { - self.ids_info.is_some() - } -} diff --git a/compiler/rustc_codegen_llvm/src/coverageinfo/mapgen.rs b/compiler/rustc_codegen_llvm/src/coverageinfo/mapgen.rs index d5133f4e7bfa..7cdce817a483 100644 --- a/compiler/rustc_codegen_llvm/src/coverageinfo/mapgen.rs +++ b/compiler/rustc_codegen_llvm/src/coverageinfo/mapgen.rs @@ -17,7 +17,6 @@ use tracing::debug; use crate::common::CodegenCx; use crate::coverageinfo::llvm_cov; -use crate::coverageinfo::map_data::FunctionCoverage; use crate::coverageinfo::mapgen::covfun::prepare_covfun_record; use crate::llvm; @@ -48,34 +47,28 @@ pub(crate) fn finalize(cx: &CodegenCx<'_, '_>) { debug!("Generating coverage map for CodegenUnit: `{}`", cx.codegen_unit.name()); - // In order to show that unused functions have coverage counts of zero (0), LLVM requires the - // 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 cx.codegen_unit.is_code_coverage_dead_code_cgu() { - add_unused_functions(cx); - } - // FIXME(#132395): Can this be none even when coverage is enabled? - let function_coverage_map = match cx.coverage_cx { - Some(ref cx) => cx.take_function_coverage_map(), + let instances_used = match cx.coverage_cx { + Some(ref cx) => cx.instances_used.borrow(), None => return, }; - if function_coverage_map.is_empty() { - // This CGU has no functions with coverage instrumentation. - return; - } let mut global_file_table = GlobalFileTable::new(); - let covfun_records = function_coverage_map - .into_iter() - .filter_map(|(instance, function_coverage)| { - let is_used = function_coverage.is_used(); - prepare_covfun_record(tcx, &mut global_file_table, instance, is_used) - }) + let mut covfun_records = instances_used + .iter() + .copied() + .filter_map(|instance| prepare_covfun_record(tcx, &mut global_file_table, instance, true)) .collect::>(); + // In a single designated CGU, also prepare covfun records for functions + // in this crate that were instrumented for coverage, but are unused. + if cx.codegen_unit.is_code_coverage_dead_code_cgu() { + covfun_records.extend(gather_unused_functions(cx).into_iter().filter_map(|instance| { + prepare_covfun_record(tcx, &mut global_file_table, instance, false) + })); + } + // If there are no covfun records for this CGU, don't generate a covmap record. // Emitting a covmap record without any covfun records causes `llvm-cov` to // fail when generating coverage reports, and if there are no covfun records @@ -251,7 +244,7 @@ fn generate_covmap_record<'ll>(cx: &CodegenCx<'ll, '_>, version: u32, filenames_ /// coverage map (in a single designated CGU) so that we still emit coverage mappings for them. /// We also end up adding their symbol names to a special global array that LLVM will include in /// its embedded coverage data. -fn add_unused_functions(cx: &CodegenCx<'_, '_>) { +fn gather_unused_functions<'tcx>(cx: &CodegenCx<'_, 'tcx>) -> Vec> { assert!(cx.codegen_unit.is_code_coverage_dead_code_cgu()); let tcx = cx.tcx; @@ -268,20 +261,17 @@ fn add_unused_functions(cx: &CodegenCx<'_, '_>) { && !usage.used_via_inlining.contains(&def_id.to_def_id()) }; - // Scan for unused functions that were instrumented for coverage. - for def_id in tcx.mir_keys(()).iter().copied().filter(|&def_id| is_unused_fn(def_id)) { - // Get the coverage info from MIR, skipping functions that were never instrumented. - let body = tcx.optimized_mir(def_id); - let Some(function_coverage_info) = body.function_coverage_info.as_deref() else { continue }; + // FIXME(79651): Consider trying to filter out dummy instantiations of + // unused generic functions from library crates, because they can produce + // "unused instantiation" in coverage reports even when they are actually + // used by some downstream crate in the same binary. - // FIXME(79651): Consider trying to filter out dummy instantiations of - // unused generic functions from library crates, because they can produce - // "unused instantiation" in coverage reports even when they are actually - // used by some downstream crate in the same binary. - - debug!("generating unused fn: {def_id:?}"); - add_unused_function_coverage(cx, def_id, function_coverage_info); - } + tcx.mir_keys(()) + .iter() + .copied() + .filter(|&def_id| is_unused_fn(def_id)) + .map(|def_id| make_dummy_instance(tcx, def_id)) + .collect::>() } struct UsageSets<'tcx> { @@ -346,16 +336,11 @@ fn prepare_usage_sets<'tcx>(tcx: TyCtxt<'tcx>) -> UsageSets<'tcx> { UsageSets { all_mono_items, used_via_inlining, missing_own_coverage } } -fn add_unused_function_coverage<'tcx>( - cx: &CodegenCx<'_, 'tcx>, - def_id: LocalDefId, - function_coverage_info: &'tcx mir::coverage::FunctionCoverageInfo, -) { - let tcx = cx.tcx; - let def_id = def_id.to_def_id(); +fn make_dummy_instance<'tcx>(tcx: TyCtxt<'tcx>, local_def_id: LocalDefId) -> ty::Instance<'tcx> { + let def_id = local_def_id.to_def_id(); // Make a dummy instance that fills in all generics with placeholders. - let instance = ty::Instance::new( + ty::Instance::new( def_id, ty::GenericArgs::for_item(tcx, def_id, |param, _| { if let ty::GenericParamDefKind::Lifetime = param.kind { @@ -364,9 +349,5 @@ fn add_unused_function_coverage<'tcx>( tcx.mk_param_from_def(param) } }), - ); - - // An unused function's mappings will all be rewritten to map to zero. - let function_coverage = FunctionCoverage::new_unused(function_coverage_info); - cx.coverage_cx().function_coverage_map.borrow_mut().insert(instance, function_coverage); + ) } diff --git a/compiler/rustc_codegen_llvm/src/coverageinfo/mod.rs b/compiler/rustc_codegen_llvm/src/coverageinfo/mod.rs index 82b6677e2038..7311cd9d230c 100644 --- a/compiler/rustc_codegen_llvm/src/coverageinfo/mod.rs +++ b/compiler/rustc_codegen_llvm/src/coverageinfo/mod.rs @@ -5,7 +5,7 @@ use rustc_abi::Size; use rustc_codegen_ssa::traits::{ BuilderMethods, ConstCodegenMethods, CoverageInfoBuilderMethods, MiscCodegenMethods, }; -use rustc_data_structures::fx::{FxHashMap, FxIndexMap}; +use rustc_data_structures::fx::{FxHashMap, FxIndexSet}; use rustc_middle::mir::coverage::CoverageKind; use rustc_middle::ty::Instance; use rustc_middle::ty::layout::HasTyCtxt; @@ -13,18 +13,16 @@ use tracing::{debug, instrument}; use crate::builder::Builder; use crate::common::CodegenCx; -use crate::coverageinfo::map_data::FunctionCoverage; use crate::llvm; pub(crate) mod ffi; mod llvm_cov; -pub(crate) mod map_data; mod mapgen; /// Extra per-CGU context/state needed for coverage instrumentation. pub(crate) struct CguCoverageContext<'ll, 'tcx> { /// Coverage data for each instrumented function identified by DefId. - pub(crate) function_coverage_map: RefCell, FunctionCoverage<'tcx>>>, + pub(crate) instances_used: RefCell>>, pub(crate) pgo_func_name_var_map: RefCell, &'ll llvm::Value>>, pub(crate) mcdc_condition_bitmap_map: RefCell, Vec<&'ll llvm::Value>>>, @@ -34,17 +32,13 @@ pub(crate) struct CguCoverageContext<'ll, 'tcx> { impl<'ll, 'tcx> CguCoverageContext<'ll, 'tcx> { pub(crate) fn new() -> Self { Self { - function_coverage_map: Default::default(), + instances_used: RefCell::>::default(), pgo_func_name_var_map: Default::default(), mcdc_condition_bitmap_map: Default::default(), covfun_section_name: Default::default(), } } - fn take_function_coverage_map(&self) -> FxIndexMap, FunctionCoverage<'tcx>> { - self.function_coverage_map.replace(FxIndexMap::default()) - } - /// LLVM use a temp value to record evaluated mcdc test vector of each decision, which is /// called condition bitmap. In order to handle nested decisions, several condition bitmaps can /// be allocated for a function body. These values are named `mcdc.addr.{i}` and are a 32-bit @@ -157,12 +151,7 @@ impl<'tcx> CoverageInfoBuilderMethods<'tcx> for Builder<'_, '_, 'tcx> { // Mark the instance as used in this CGU, for coverage purposes. // This includes functions that were not partitioned into this CGU, // but were MIR-inlined into one of this CGU's functions. - coverage_cx.function_coverage_map.borrow_mut().entry(instance).or_insert_with(|| { - FunctionCoverage::new_used( - function_coverage_info, - bx.tcx.coverage_ids_info(instance.def), - ) - }); + coverage_cx.instances_used.borrow_mut().insert(instance); match *kind { CoverageKind::SpanMarker | CoverageKind::BlockMarker { .. } => unreachable!(