bjoernager/rust
bjoernager/rust
1
Fork 0
Code Activity

Addressed feedback from 2020-12-01

Browse source 
Added one more test (two files) showing coverage of generics and unused
functions across crates.

Created and referenced new Issues, as requested.

Added comments.

Added a note about the possible effects of compiler options on LLVM
coverage maps.
This commit is contained in:
Rich Kadel 2020-12-01 23:01:26 -08:00
parent def932ca86
commit d96f351fa3
28 changed files with 1797 additions and 366 deletions
Download patch file Download diff file Expand all files Collapse all files

19
compiler/rustc_codegen_llvm/src/coverageinfo/mapgen.rs
View file

@ -262,6 +262,10 @@ fn add_unreachable_coverage<'tcx>(
tcx: TyCtxt<'tcx>,
function_coverage_map: &mut FxHashMap<Instance<'tcx>, FunctionCoverage<'tcx>>,
) {
// 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)?
// Note: If the crate *only* defines generic functions, there are no codegenerated non-generic
// functions to add any unreachable code to. In this case, the unreachable code regions will
// have no coverage, instead of having coverage with zero executions.
@ -359,6 +363,21 @@ fn add_unreachable_coverage<'tcx>(
for def_id in
unreachable_def_ids_by_file.remove(&covered_file_name).into_iter().flatten()
{
// Note, this loop adds an unreachable code regions for each MIR-derived region.
// Alternatively, we could add a single code region for the maximum span of all
// code regions here.
//
// Observed downsides of this approach are:
//
// 1. The coverage results will appear inconsistent compared with the same (or
// similar) code in a function that is reached.
// 2. If the function is unreachable from one crate but reachable when compiling
// another referencing crate (such as a cross-crate reference to a
// generic function or inlined function), actual coverage regions overlaid
// on a single larger code span of `Zero` coverage can appear confusing or
// wrong. Chaning the unreachable coverage from a `code_region` to a
// `gap_region` can help, but still can look odd with `0` line counts for
// lines between executed (> 0) lines (such as for blank lines or comments).
for &region in tcx.covered_code_regions(def_id) {
function_coverage.add_unreachable_region(region.clone());
}