Author: Duncan P. N. Exon Smith Date: 2021-04-22T11:29:39-07:00 New Revision: d4ee603c8f21b4ae722c2a34d4dfa54b7abeeb16
URL: https://github.com/llvm/llvm-project/commit/d4ee603c8f21b4ae722c2a34d4dfa54b7abeeb16 DIFF: https://github.com/llvm/llvm-project/commit/d4ee603c8f21b4ae722c2a34d4dfa54b7abeeb16.diff LOG: Coverage: Document how to collect a profile without a filesystem The profiling runtime was designed to work without static initializers or a a filesystem (see 117cf2bd1ff585f9754b5f30f5a4cfd65b230bbf and others). The no-static-initializers part was already documented but this part got missed before. Differential Revision: https://reviews.llvm.org/D101000 Added: Modified: clang/docs/SourceBasedCodeCoverage.rst Removed: ################################################################################ diff --git a/clang/docs/SourceBasedCodeCoverage.rst b/clang/docs/SourceBasedCodeCoverage.rst index a54bba94eb98..5f4bcf8e0ff0 100644 --- a/clang/docs/SourceBasedCodeCoverage.rst +++ b/clang/docs/SourceBasedCodeCoverage.rst @@ -346,6 +346,34 @@ without using static initializers, do this manually: In C++ files, declare these as ``extern "C"``. +Using the profiling runtime without a filesystem +------------------------------------------------ + +The profiling runtime also supports freestanding environments that lack a +filesystem. The runtime ships as a static archive that's structured to make +dependencies on a hosted environment optional, depending on what features +the client application uses. + +The first step is to export ``__llvm_profile_runtime``, as above, to disable +the default static initializers. Instead of calling the ``*_file()`` APIs +described above, use the following to save the profile directly to a buffer +under your control: + +* Forward-declare ``uint64_t __llvm_profile_get_size_for_buffer(void)`` and + call it to determine the size of the profile. You'll need to allocate a + buffer of this size. + +* Forward-declare ``int __llvm_profile_write_buffer(char *Buffer)`` and call it + to copy the current counters to ``Buffer``, which is expected to already be + allocated and big enough for the profile. + +* Optionally, forward-declare ``void __llvm_profile_reset_counters(void)`` and + call it to reset the counters before entering a specific section to be + profiled. This is only useful if there is some setup that should be excluded + from the profile. + +In C++ files, declare these as ``extern "C"``. + Collecting coverage reports for the llvm project ================================================ _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
