[all-commits] [llvm/llvm-project] 395e62: [llvm-cov] Add failing test for gap region line co...

[Maksim Levental via All-commits]

  Branch: refs/heads/users/makslevental/fix-gap-region-line-coverage
  Home:   https://github.com/llvm/llvm-project
  Commit: 395e62e7e9c66f64ee5ab3f931e11f753833dd47
      https://github.com/llvm/llvm-project/commit/395e62e7e9c66f64ee5ab3f931e11f753833dd47
  Author: makslevental <maksim.levental at gmail.com>
  Date:   2026-06-13 (Sat, 13 Jun 2026)

  Changed paths:
    A llvm/test/tools/llvm-cov/Inputs/gap-region-quirk/gap-quirk.covmapping
    A llvm/test/tools/llvm-cov/Inputs/gap-region-quirk/gap-quirk.cpp
    A llvm/test/tools/llvm-cov/Inputs/gap-region-quirk/gap-quirk.profdata
    A llvm/test/tools/llvm-cov/gap-region-line-coverage.test

  Log Message:
  -----------
  [llvm-cov] Add failing test for gap region line coverage bug

LineCoverageStats incorrectly reports a line as uncovered when the
wrapping segment has count=0 and the line has no region entries, even
if it has non-entry segments with count > 0.

This test uses coverage data from Apple clang which produces the
specific segment pattern that triggers this: a closing brace "}" after
a never-taken if-block, where the non-gap segment returning to the
parent function's count is ignored.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply at anthropic.com>


  Commit: f20f81cc976d692ec0fcf91164aafaa0ee88b9e6
      https://github.com/llvm/llvm-project/commit/f20f81cc976d692ec0fcf91164aafaa0ee88b9e6
  Author: makslevental <maksim.levental at gmail.com>
  Date:   2026-06-13 (Sat, 13 Jun 2026)

  Changed paths:
    M llvm/lib/ProfileData/Coverage/CoverageMapping.cpp

  Log Message:
  -----------
  [CoverageMapping] Fix LineCoverageStats incorrectly using gap region count

When a line's wrapping segment is a gap region with count=0, but the
line has non-gap segments with count > 0 (not region entries),
LineCoverageStats incorrectly reports the line as uncovered.

This happens when a zero-count region (e.g., from a never-taken
if-branch) extends past subsequent covered lines via a gap segment.
The fix:
1. Skip initializing ExecutionCount from gap wrapping segments
2. When MinRegionCount is 0, check non-gap HasCount segments on the
   line and use their max count

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply at anthropic.com>


Compare: https://github.com/llvm/llvm-project/compare/395e62e7e9c6%5E...f20f81cc976d

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