From e178a5beb36960902379040ee0b667fb0a8eee93 Mon Sep 17 00:00:00 2001 From: Greg Hackmann Date: Tue, 14 May 2019 15:45:31 -0700 Subject: gcov: clang support LLVM uses profiling data that's deliberately similar to GCC, but has a very different way of exporting that data. LLVM calls llvm_gcov_init() once per module, and provides a couple of callbacks that we can use to ask for more data. We care about the "writeout" callback, which in turn calls back into compiler-rt/this module to dump all the gathered coverage data to disk: llvm_gcda_start_file() llvm_gcda_emit_function() llvm_gcda_emit_arcs() llvm_gcda_emit_function() llvm_gcda_emit_arcs() [... repeats for each function ...] llvm_gcda_summary_info() llvm_gcda_end_file() This design is much more stateless and unstructured than gcc's, and is intended to run at process exit. This forces us to keep some local state about which module we're dealing with at the moment. On the other hand, it also means we don't depend as much on how LLVM represents profiling data internally. See LLVM's lib/Transforms/Instrumentation/GCOVProfiling.cpp for more details on how this works, particularly GCOVProfiler::emitProfileArcs(), GCOVProfiler::insertCounterWriteout(), and GCOVProfiler::insertFlush(). [akpm@linux-foundation.org: coding-style fixes] Link: http://lkml.kernel.org/r/20190417225328.208129-1-trong@android.com Signed-off-by: Greg Hackmann Signed-off-by: Nick Desaulniers Signed-off-by: Tri Vo Co-developed-by: Nick Desaulniers Co-developed-by: Tri Vo Tested-by: Trilok Soni Tested-by: Prasad Sodagudi Tested-by: Tri Vo Tested-by: Daniel Mentz Tested-by: Petri Gynther Reviewed-by: Peter Oberparleiter Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/gcov/gcov.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'kernel/gcov/gcov.h') diff --git a/kernel/gcov/gcov.h b/kernel/gcov/gcov.h index 0ecf1d664ec3..6ab2c1808c9d 100644 --- a/kernel/gcov/gcov.h +++ b/kernel/gcov/gcov.h @@ -15,6 +15,7 @@ #ifndef GCOV_H #define GCOV_H GCOV_H +#include #include /* @@ -46,6 +47,7 @@ unsigned int gcov_info_version(struct gcov_info *info); struct gcov_info *gcov_info_next(struct gcov_info *info); void gcov_info_link(struct gcov_info *info); void gcov_info_unlink(struct gcov_info *prev, struct gcov_info *info); +bool gcov_info_within_module(struct gcov_info *info, struct module *mod); /* Base interface. */ enum gcov_action { -- cgit v1.2.3