diff --git a/compiler/rustc_codegen_llvm/src/coverageinfo/llvm_cov.rs b/compiler/rustc_codegen_llvm/src/coverageinfo/llvm_cov.rs new file mode 100644 index 0000000000000..56ba45c21ee15 --- /dev/null +++ b/compiler/rustc_codegen_llvm/src/coverageinfo/llvm_cov.rs @@ -0,0 +1,102 @@ +//! Safe wrappers for coverage-specific FFI functions. + +use std::ffi::CString; + +use libc::c_uint; + +use crate::common::AsCCharPtr; +use crate::coverageinfo::ffi; +use crate::llvm; + +pub(crate) fn covmap_var_name() -> CString { + CString::new(llvm::build_byte_buffer(|s| unsafe { + llvm::LLVMRustCoverageWriteMappingVarNameToString(s); + })) + .expect("covmap variable name should not contain NUL") +} + +pub(crate) fn covmap_section_name(llmod: &llvm::Module) -> CString { + CString::new(llvm::build_byte_buffer(|s| unsafe { + llvm::LLVMRustCoverageWriteMapSectionNameToString(llmod, s); + })) + .expect("covmap section name should not contain NUL") +} + +pub(crate) fn covfun_section_name(llmod: &llvm::Module) -> CString { + CString::new(llvm::build_byte_buffer(|s| unsafe { + llvm::LLVMRustCoverageWriteFuncSectionNameToString(llmod, s); + })) + .expect("covfun section name should not contain NUL") +} + +pub(crate) fn create_pgo_func_name_var<'ll>( + llfn: &'ll llvm::Value, + mangled_fn_name: &str, +) -> &'ll llvm::Value { + unsafe { + llvm::LLVMRustCoverageCreatePGOFuncNameVar( + llfn, + mangled_fn_name.as_c_char_ptr(), + mangled_fn_name.len(), + ) + } +} + +pub(crate) fn write_filenames_to_buffer<'a>( + filenames: impl IntoIterator, +) -> Vec { + let (pointers, lengths) = filenames + .into_iter() + .map(|s: &str| (s.as_c_char_ptr(), s.len())) + .unzip::<_, _, Vec<_>, Vec<_>>(); + + llvm::build_byte_buffer(|buffer| unsafe { + llvm::LLVMRustCoverageWriteFilenamesSectionToBuffer( + pointers.as_ptr(), + pointers.len(), + lengths.as_ptr(), + lengths.len(), + buffer, + ); + }) +} + +pub(crate) fn write_function_mappings_to_buffer( + virtual_file_mapping: &[u32], + expressions: &[ffi::CounterExpression], + code_regions: &[ffi::CodeRegion], + branch_regions: &[ffi::BranchRegion], + mcdc_branch_regions: &[ffi::MCDCBranchRegion], + mcdc_decision_regions: &[ffi::MCDCDecisionRegion], +) -> Vec { + llvm::build_byte_buffer(|buffer| unsafe { + llvm::LLVMRustCoverageWriteMappingToBuffer( + virtual_file_mapping.as_ptr(), + virtual_file_mapping.len() as c_uint, + expressions.as_ptr(), + expressions.len() as c_uint, + code_regions.as_ptr(), + code_regions.len() as c_uint, + branch_regions.as_ptr(), + branch_regions.len() as c_uint, + mcdc_branch_regions.as_ptr(), + mcdc_branch_regions.len() as c_uint, + mcdc_decision_regions.as_ptr(), + mcdc_decision_regions.len() as c_uint, + buffer, + ) + }) +} + +/// Hashes some bytes into a 64-bit hash, via LLVM's `IndexedInstrProf::ComputeHash`, +/// as required for parts of the LLVM coverage mapping format. +pub(crate) fn hash_bytes(bytes: &[u8]) -> u64 { + unsafe { llvm::LLVMRustCoverageHashByteArray(bytes.as_c_char_ptr(), bytes.len()) } +} + +/// Returns LLVM's `coverage::CovMapVersion::CurrentVersion` (CoverageMapping.h) +/// as a raw numeric value. For historical reasons, the numeric value is 1 less +/// than the number in the version's name, so `Version7` is actually `6u32`. +pub(crate) fn mapping_version() -> u32 { + unsafe { llvm::LLVMRustCoverageMappingVersion() } +} diff --git a/compiler/rustc_codegen_llvm/src/coverageinfo/mapgen.rs b/compiler/rustc_codegen_llvm/src/coverageinfo/mapgen.rs index f6378199fe26e..bb2f634cb2592 100644 --- a/compiler/rustc_codegen_llvm/src/coverageinfo/mapgen.rs +++ b/compiler/rustc_codegen_llvm/src/coverageinfo/mapgen.rs @@ -1,4 +1,5 @@ use std::ffi::CString; +use std::iter; use itertools::Itertools as _; use rustc_abi::Align; @@ -17,9 +18,9 @@ use rustc_target::spec::HasTargetSpec; use tracing::debug; use crate::common::CodegenCx; -use crate::coverageinfo::ffi; use crate::coverageinfo::map_data::{FunctionCoverage, FunctionCoverageCollector}; -use crate::{coverageinfo, llvm}; +use crate::coverageinfo::{ffi, llvm_cov}; +use crate::llvm; /// Generates and exports the coverage map, which is embedded in special /// linker sections in the final binary. @@ -33,7 +34,7 @@ pub(crate) fn finalize(cx: &CodegenCx<'_, '_>) { // agrees with our Rust-side code. Expected versions (encoded as n-1) are: // - `CovMapVersion::Version7` (6) used by LLVM 18-19 let covmap_version = { - let llvm_covmap_version = coverageinfo::mapping_version(); + let llvm_covmap_version = llvm_cov::mapping_version(); let expected_versions = 6..=6; assert!( expected_versions.contains(&llvm_covmap_version), @@ -78,7 +79,7 @@ pub(crate) fn finalize(cx: &CodegenCx<'_, '_>) { let filenames_size = filenames_buffer.len(); let filenames_val = cx.const_bytes(&filenames_buffer); - let filenames_ref = coverageinfo::hash_bytes(&filenames_buffer); + let filenames_ref = llvm_cov::hash_bytes(&filenames_buffer); // Generate the coverage map header, which contains the filenames used by // this CGU's coverage mappings, and store it in a well-known global. @@ -187,13 +188,10 @@ impl GlobalFileTable { .for_scope(tcx.sess, RemapPathScopeComponents::MACRO) .to_string_lossy(); - llvm::build_byte_buffer(|buffer| { - coverageinfo::write_filenames_section_to_buffer( - // Insert the working dir at index 0, before the other filenames. - std::iter::once(working_dir).chain(self.raw_file_table.iter().map(Symbol::as_str)), - buffer, - ); - }) + // 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) } } @@ -296,17 +294,14 @@ fn encode_mappings_for_function( } // Encode the function's coverage mappings into a buffer. - llvm::build_byte_buffer(|buffer| { - coverageinfo::write_mapping_to_buffer( - virtual_file_mapping.into_vec(), - expressions, - &code_regions, - &branch_regions, - &mcdc_branch_regions, - &mcdc_decision_regions, - buffer, - ); - }) + llvm_cov::write_function_mappings_to_buffer( + &virtual_file_mapping.into_vec(), + &expressions, + &code_regions, + &branch_regions, + &mcdc_branch_regions, + &mcdc_decision_regions, + ) } /// Generates the contents of the covmap record for this CGU, which mostly @@ -335,23 +330,11 @@ fn generate_covmap_record<'ll>( let covmap_data = cx.const_struct(&[cov_data_header_val, filenames_val], /*packed=*/ false); - let covmap_var_name = CString::new(llvm::build_byte_buffer(|s| unsafe { - llvm::LLVMRustCoverageWriteMappingVarNameToString(s); - })) - .unwrap(); - debug!("covmap var name: {:?}", covmap_var_name); - - let covmap_section_name = CString::new(llvm::build_byte_buffer(|s| unsafe { - llvm::LLVMRustCoverageWriteMapSectionNameToString(cx.llmod, s); - })) - .expect("covmap section name should not contain NUL"); - debug!("covmap section name: {:?}", covmap_section_name); - - let llglobal = llvm::add_global(cx.llmod, cx.val_ty(covmap_data), &covmap_var_name); + let llglobal = llvm::add_global(cx.llmod, cx.val_ty(covmap_data), &llvm_cov::covmap_var_name()); llvm::set_initializer(llglobal, covmap_data); llvm::set_global_constant(llglobal, true); llvm::set_linkage(llglobal, llvm::Linkage::PrivateLinkage); - llvm::set_section(llglobal, &covmap_section_name); + llvm::set_section(llglobal, &llvm_cov::covmap_section_name(cx.llmod)); // LLVM's coverage mapping format specifies 8-byte alignment for items in this section. // llvm::set_alignment(llglobal, Align::EIGHT); @@ -373,7 +356,7 @@ fn generate_covfun_record( let coverage_mapping_size = coverage_mapping_buffer.len(); let coverage_mapping_val = cx.const_bytes(&coverage_mapping_buffer); - let func_name_hash = coverageinfo::hash_bytes(mangled_function_name.as_bytes()); + let func_name_hash = llvm_cov::hash_bytes(mangled_function_name.as_bytes()); let func_name_hash_val = cx.const_u64(func_name_hash); let coverage_mapping_size_val = cx.const_u32(coverage_mapping_size as u32); let source_hash_val = cx.const_u64(source_hash); diff --git a/compiler/rustc_codegen_llvm/src/coverageinfo/mod.rs b/compiler/rustc_codegen_llvm/src/coverageinfo/mod.rs index aaba0684c1296..bf773cd2667ab 100644 --- a/compiler/rustc_codegen_llvm/src/coverageinfo/mod.rs +++ b/compiler/rustc_codegen_llvm/src/coverageinfo/mod.rs @@ -1,24 +1,23 @@ use std::cell::{OnceCell, RefCell}; use std::ffi::{CStr, CString}; -use libc::c_uint; use rustc_abi::Size; use rustc_codegen_ssa::traits::{ BuilderMethods, ConstCodegenMethods, CoverageInfoBuilderMethods, MiscCodegenMethods, }; use rustc_data_structures::fx::{FxHashMap, FxIndexMap}; -use rustc_llvm::RustString; use rustc_middle::mir::coverage::CoverageKind; use rustc_middle::ty::Instance; use rustc_middle::ty::layout::HasTyCtxt; use tracing::{debug, instrument}; use crate::builder::Builder; -use crate::common::{AsCCharPtr, CodegenCx}; +use crate::common::CodegenCx; use crate::coverageinfo::map_data::FunctionCoverageCollector; use crate::llvm; pub(crate) mod ffi; +mod llvm_cov; pub(crate) mod map_data; mod mapgen; @@ -80,12 +79,9 @@ impl<'ll, 'tcx> CodegenCx<'ll, 'tcx> { /// - `__LLVM_COV,__llvm_covfun` on macOS (includes `__LLVM_COV,` segment prefix) /// - `.lcovfun$M` on Windows (includes `$M` sorting suffix) fn covfun_section_name(&self) -> &CStr { - self.coverage_cx().covfun_section_name.get_or_init(|| { - CString::new(llvm::build_byte_buffer(|s| unsafe { - llvm::LLVMRustCoverageWriteFuncSectionNameToString(self.llmod, s); - })) - .expect("covfun section name should not contain NUL") - }) + self.coverage_cx() + .covfun_section_name + .get_or_init(|| llvm_cov::covfun_section_name(self.llmod)) } /// For LLVM codegen, returns a function-specific `Value` for a global @@ -95,9 +91,11 @@ impl<'ll, 'tcx> CodegenCx<'ll, 'tcx> { fn get_pgo_func_name_var(&self, instance: Instance<'tcx>) -> &'ll llvm::Value { debug!("getting pgo_func_name_var for instance={:?}", instance); let mut pgo_func_name_var_map = self.coverage_cx().pgo_func_name_var_map.borrow_mut(); - pgo_func_name_var_map - .entry(instance) - .or_insert_with(|| create_pgo_func_name_var(self, instance)) + pgo_func_name_var_map.entry(instance).or_insert_with(|| { + let llfn = self.get_fn(instance); + let mangled_fn_name: &str = self.tcx.symbol_name(instance).name; + llvm_cov::create_pgo_func_name_var(llfn, mangled_fn_name) + }) } } @@ -225,80 +223,3 @@ impl<'tcx> CoverageInfoBuilderMethods<'tcx> for Builder<'_, '_, 'tcx> { } } } - -/// Calls llvm::createPGOFuncNameVar() with the given function instance's -/// mangled function name. The LLVM API returns an llvm::GlobalVariable -/// containing the function name, with the specific variable name and linkage -/// required by LLVM InstrProf source-based coverage instrumentation. Use -/// `bx.get_pgo_func_name_var()` to ensure the variable is only created once per -/// `Instance`. -fn create_pgo_func_name_var<'ll, 'tcx>( - cx: &CodegenCx<'ll, 'tcx>, - instance: Instance<'tcx>, -) -> &'ll llvm::Value { - let mangled_fn_name: &str = cx.tcx.symbol_name(instance).name; - let llfn = cx.get_fn(instance); - unsafe { - llvm::LLVMRustCoverageCreatePGOFuncNameVar( - llfn, - mangled_fn_name.as_c_char_ptr(), - mangled_fn_name.len(), - ) - } -} - -pub(crate) fn write_filenames_section_to_buffer<'a>( - filenames: impl IntoIterator, - buffer: &RustString, -) { - let (pointers, lengths) = filenames - .into_iter() - .map(|s: &str| (s.as_c_char_ptr(), s.len())) - .unzip::<_, _, Vec<_>, Vec<_>>(); - - unsafe { - llvm::LLVMRustCoverageWriteFilenamesSectionToBuffer( - pointers.as_ptr(), - pointers.len(), - lengths.as_ptr(), - lengths.len(), - buffer, - ); - } -} - -pub(crate) fn write_mapping_to_buffer( - virtual_file_mapping: Vec, - expressions: Vec, - code_regions: &[ffi::CodeRegion], - branch_regions: &[ffi::BranchRegion], - mcdc_branch_regions: &[ffi::MCDCBranchRegion], - mcdc_decision_regions: &[ffi::MCDCDecisionRegion], - buffer: &RustString, -) { - unsafe { - llvm::LLVMRustCoverageWriteMappingToBuffer( - virtual_file_mapping.as_ptr(), - virtual_file_mapping.len() as c_uint, - expressions.as_ptr(), - expressions.len() as c_uint, - code_regions.as_ptr(), - code_regions.len() as c_uint, - branch_regions.as_ptr(), - branch_regions.len() as c_uint, - mcdc_branch_regions.as_ptr(), - mcdc_branch_regions.len() as c_uint, - mcdc_decision_regions.as_ptr(), - mcdc_decision_regions.len() as c_uint, - buffer, - ); - } -} - -pub(crate) fn hash_bytes(bytes: &[u8]) -> u64 { - unsafe { llvm::LLVMRustCoverageHashByteArray(bytes.as_c_char_ptr(), bytes.len()) } -} - -pub(crate) fn mapping_version() -> u32 { - unsafe { llvm::LLVMRustCoverageMappingVersion() } -}