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Update CoverageMappingFormat Support to Version6

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Version 5 adds Branch Regions which are a prerequisite for branch coverage.
Version 6 can use the zeroth filename as prefix for other relative files.
This commit is contained in:
Arpad Borsos 2021-10-19 11:09:43 +02:00 • committed by Rich Kadel
parent 7b3cd075bb
commit 566ad8da45
6 changed files with 66 additions and 23 deletions
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20
compiler/rustc_codegen_llvm/src/coverageinfo/mapgen.rs
View file

@ -17,10 +17,10 @@ use tracing::debug;
/// Generates and exports the Coverage Map.
///
/// This Coverage Map complies with Coverage Mapping Format version 4 (zero-based encoded as 3),
/// as defined at [LLVM Code Coverage Mapping Format](https://github.com/rust-lang/llvm-project/blob/rustc/11.0-2020-10-12/llvm/docs/CoverageMappingFormat.rst#llvm-code-coverage-mapping-format)
/// and published in Rust's November 2020 fork of LLVM. This version is supported by the LLVM
/// coverage tools (`llvm-profdata` and `llvm-cov`) bundled with Rust's fork of LLVM.
/// This Coverage Map complies with Coverage Mapping Format version 5 (zero-based encoded as 4),
/// as defined at [LLVM Code Coverage Mapping Format](https://github.com/rust-lang/llvm-project/blob/rustc/13.0-2021-09-30/llvm/docs/CoverageMappingFormat.rst#llvm-code-coverage-mapping-format).
/// This version is supported by the LLVM coverage tools (`llvm-profdata` and `llvm-cov`)
/// bundled with Rust's fork of LLVM.
///
/// Consequently, Rust's bundled version of Clang also generates Coverage Maps compliant with
/// the same version. Clang's implementation of Coverage Map generation was referenced when
@ -30,12 +30,12 @@ use tracing::debug;
pub fn finalize<'ll, 'tcx>(cx: &CodegenCx<'ll, 'tcx>) {
let tcx = cx.tcx;
// Ensure LLVM supports Coverage Map Version 4 (encoded as a zero-based value: 3).
// If not, the LLVM Version must be less than 11.
let version = coverageinfo::mapping_version();
if version != 3 {
tcx.sess.fatal("rustc option `-Z instrument-coverage` requires LLVM 11 or higher.");
}
// While our bundled LLVM might support Coverage Map Version 6
// (encoded as a zero-based value: 5), we clamp that to Version 5,
// as Version 6 would require us to use the 0-th filename as a path prefix
// for all other relative paths, which we don't take advantage of right now.
let _version = coverageinfo::mapping_version();
let version = 4;
debug!("Generating coverage map for CodegenUnit: `{}`", cx.codegen_unit.name());

42
compiler/rustc_codegen_llvm/src/llvm/ffi.rs
View file

@ -681,7 +681,7 @@ pub type InlineAsmDiagHandler = unsafe extern "C" fn(&SMDiagnostic, *const c_voi
pub mod coverageinfo {
use super::coverage_map;
/// Aligns with [llvm::coverage::CounterMappingRegion::RegionKind](https://github.com/rust-lang/llvm-project/blob/rustc/11.0-2020-10-12/llvm/include/llvm/ProfileData/Coverage/CoverageMapping.h#L206-L222)
/// Aligns with [llvm::coverage::CounterMappingRegion::RegionKind](https://github.com/rust-lang/llvm-project/blob/rustc/13.0-2021-09-30/llvm/include/llvm/ProfileData/Coverage/CoverageMapping.h#L209-L230)
#[derive(Copy, Clone, Debug)]
#[repr(C)]
pub enum RegionKind {
@ -700,11 +700,16 @@ pub mod coverageinfo {
/// A GapRegion is like a CodeRegion, but its count is only set as the
/// line execution count when its the only region in the line.
GapRegion = 3,
/// A BranchRegion represents leaf-level boolean expressions and is
/// associated with two counters, each representing the number of times the
/// expression evaluates to true or false.
BranchRegion = 4,
}
/// This struct provides LLVM's representation of a "CoverageMappingRegion", encoded into the
/// coverage map, in accordance with the
/// [LLVM Code Coverage Mapping Format](https://github.com/rust-lang/llvm-project/blob/rustc/11.0-2020-10-12/llvm/docs/CoverageMappingFormat.rst#llvm-code-coverage-mapping-format).
/// [LLVM Code Coverage Mapping Format](https://github.com/rust-lang/llvm-project/blob/rustc/13.0-2021-09-30/llvm/docs/CoverageMappingFormat.rst#llvm-code-coverage-mapping-format).
/// The struct composes fields representing the `Counter` type and value(s) (injected counter
/// ID, or expression type and operands), the source file (an indirect index into a "filenames
/// array", encoded separately), and source location (start and end positions of the represented
@ -717,6 +722,10 @@ pub mod coverageinfo {
/// The counter type and type-dependent counter data, if any.
counter: coverage_map::Counter,
/// If the `RegionKind` is a `BranchRegion`, this represents the counter
/// for the false branch of the region.
false_counter: coverage_map::Counter,
/// An indirect reference to the source filename. In the LLVM Coverage Mapping Format, the
/// file_id is an index into a function-specific `virtual_file_mapping` array of indexes
/// that, in turn, are used to look up the filename for this region.
@ -754,6 +763,7 @@ pub mod coverageinfo {
) -> Self {
Self {
counter,
false_counter: coverage_map::Counter::zero(),
file_id,
expanded_file_id: 0,
start_line,
@ -764,6 +774,31 @@ pub mod coverageinfo {
}
}
// This function might be used in the future; the LLVM API is still evolving, as is coverage
// support.
#[allow(dead_code)]
crate fn branch_region(
counter: coverage_map::Counter,
false_counter: coverage_map::Counter,
file_id: u32,
start_line: u32,
start_col: u32,
end_line: u32,
end_col: u32,
) -> Self {
Self {
counter,
false_counter,
file_id,
expanded_file_id: 0,
start_line,
start_col,
end_line,
end_col,
kind: RegionKind::BranchRegion,
}
}
// This function might be used in the future; the LLVM API is still evolving, as is coverage
// support.
#[allow(dead_code)]
@ -777,6 +812,7 @@ pub mod coverageinfo {
) -> Self {
Self {
counter: coverage_map::Counter::zero(),
false_counter: coverage_map::Counter::zero(),
file_id,
expanded_file_id,
start_line,
@ -799,6 +835,7 @@ pub mod coverageinfo {
) -> Self {
Self {
counter: coverage_map::Counter::zero(),
false_counter: coverage_map::Counter::zero(),
file_id,
expanded_file_id: 0,
start_line,
@ -822,6 +859,7 @@ pub mod coverageinfo {
) -> Self {
Self {
counter,
false_counter: coverage_map::Counter::zero(),
file_id,
expanded_file_id: 0,
start_line,