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authorGreg Hackmann <ghackmann@android.com>2019-05-14 15:45:31 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2019-05-14 19:52:51 -0700
commite178a5beb36960902379040ee0b667fb0a8eee93 (patch)
tree03b2302179b767410a313fdf9003e9e5dce702e8 /kernel/gcov/gcc_3_4.c
parentaa069a23a220e9ab00d6837b76917952d0fb587e (diff)
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 <ghackmann@android.com> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: Tri Vo <trong@android.com> Co-developed-by: Nick Desaulniers <ndesaulniers@google.com> Co-developed-by: Tri Vo <trong@android.com> Tested-by: Trilok Soni <tsoni@quicinc.com> Tested-by: Prasad Sodagudi <psodagud@quicinc.com> Tested-by: Tri Vo <trong@android.com> Tested-by: Daniel Mentz <danielmentz@google.com> Tested-by: Petri Gynther <pgynther@google.com> Reviewed-by: Peter Oberparleiter <oberpar@linux.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel/gcov/gcc_3_4.c')
-rw-r--r--kernel/gcov/gcc_3_4.c12
1 files changed, 12 insertions, 0 deletions
diff --git a/kernel/gcov/gcc_3_4.c b/kernel/gcov/gcc_3_4.c
index 2dddecbdbe6e..801ee4b0b969 100644
--- a/kernel/gcov/gcc_3_4.c
+++ b/kernel/gcov/gcc_3_4.c
@@ -137,6 +137,18 @@ void gcov_info_unlink(struct gcov_info *prev, struct gcov_info *info)
gcov_info_head = info->next;
}
+/**
+ * gcov_info_within_module - check if a profiling data set belongs to a module
+ * @info: profiling data set
+ * @mod: module
+ *
+ * Returns true if profiling data belongs module, false otherwise.
+ */
+bool gcov_info_within_module(struct gcov_info *info, struct module *mod)
+{
+ return within_module((unsigned long)info, mod);
+}
+
/* Symbolic links to be created for each profiling data file. */
const struct gcov_link gcov_link[] = {
{ OBJ_TREE, "gcno" }, /* Link to .gcno file in $(objtree). */