Author: Vedant Kumar Date: 2021-02-12T12:05:38-08:00 New Revision: 13bd6fb43da9e9b1d7e82272325ec781d1f16456
URL: https://github.com/llvm/llvm-project/commit/13bd6fb43da9e9b1d7e82272325ec781d1f16456 DIFF: https://github.com/llvm/llvm-project/commit/13bd6fb43da9e9b1d7e82272325ec781d1f16456.diff LOG: [docs/Coverage] Answer FAQ about optimization Added: Modified: clang/docs/SourceBasedCodeCoverage.rst Removed: ################################################################################ diff --git a/clang/docs/SourceBasedCodeCoverage.rst b/clang/docs/SourceBasedCodeCoverage.rst index 90feb41b0a3f..b9cfe0f90297 100644 --- a/clang/docs/SourceBasedCodeCoverage.rst +++ b/clang/docs/SourceBasedCodeCoverage.rst @@ -305,6 +305,19 @@ Format compatibility guarantees minor version increment is for added functionality, and patch version increments are for bugfixes. +Impact of llvm optimizations on coverage reports +================================================ + +llvm optimizations (such as inlining or CFG simplification) should have no +impact on coverage report quality. This is due to the fact that the mapping +from source regions to profile counters is immutable, and is generated before +the llvm optimizer kicks in. The optimizer can't prove that profile counter +instrumentation is safe to delete (because it's not: it affects the profile the +program emits), and so leaves it alone. + +Note that this coverage feature does not rely on information that can degrade +during the course of optimization, such as debug info line tables. + Using the profiling runtime without static initializers ======================================================= _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
