diff options
| author | Greg Hackmann <ghackmann@android.com> | 2019-05-15 00:45:31 +0200 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2019-05-15 04:52:51 +0200 |
| commit | e178a5beb36960902379040ee0b667fb0a8eee93 (patch) | |
| tree | 03b2302179b767410a313fdf9003e9e5dce702e8 /kernel/gcov/Kconfig | |
| parent | gcov: docs: add a note on GCC vs Clang differences (diff) | |
| download | linux-e178a5beb36960902379040ee0b667fb0a8eee93.tar.xz linux-e178a5beb36960902379040ee0b667fb0a8eee93.zip | |
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/Kconfig')
| -rw-r--r-- | kernel/gcov/Kconfig | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/kernel/gcov/Kconfig b/kernel/gcov/Kconfig index 1e3823fa799b..f71c1adcff31 100644 --- a/kernel/gcov/Kconfig +++ b/kernel/gcov/Kconfig @@ -53,6 +53,7 @@ config GCOV_PROFILE_ALL choice prompt "Specify GCOV format" depends on GCOV_KERNEL + depends on CC_IS_GCC ---help--- The gcov format is usually determined by the GCC version, and the default is chosen according to your GCC version. However, there are @@ -62,7 +63,7 @@ choice config GCOV_FORMAT_3_4 bool "GCC 3.4 format" - depends on CC_IS_GCC && GCC_VERSION < 40700 + depends on GCC_VERSION < 40700 ---help--- Select this option to use the format defined by GCC 3.4. |