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* gcov: re-fix clang-11+ supportNick Desaulniers2021-04-091-10/+19
| | | | | | | | | | | | | | | | | | | | | | | | | | | LLVM changed the expected function signature for llvm_gcda_emit_function() in the clang-11 release. Users of clang-11 or newer may have noticed their kernels producing invalid coverage information: $ llvm-cov gcov -a -c -u -f -b <input>.gcda -- gcno=<input>.gcno 1 <func>: checksum mismatch, \ (<lineno chksum A>, <cfg chksum B>) != (<lineno chksum A>, <cfg chksum C>) 2 Invalid .gcda File! ... Fix up the function signatures so calling this function interprets its parameters correctly and computes the correct cfg checksum. In particular, in clang-11, the additional checksum is no longer optional. Link: https://reviews.llvm.org/rG25544ce2df0daa4304c07e64b9c8b0f7df60c11d Link: https://lkml.kernel.org/r/20210408184631.1156669-1-ndesaulniers@google.com Reported-by: Prasad Sodagudi <psodagud@quicinc.com> Tested-by: Prasad Sodagudi <psodagud@quicinc.com> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Nathan Chancellor <nathan@kernel.org> Cc: <stable@vger.kernel.org> [5.4+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* gcov: fix clang-11+ supportNick Desaulniers2021-03-251-0/+69
| | | | | | | | | | | | | | | | | | | | | | | LLVM changed the expected function signatures for llvm_gcda_start_file() and llvm_gcda_emit_function() in the clang-11 release. Users of clang-11 or newer may have noticed their kernels failing to boot due to a panic when enabling CONFIG_GCOV_KERNEL=y +CONFIG_GCOV_PROFILE_ALL=y. Fix up the function signatures so calling these functions doesn't panic the kernel. Link: https://reviews.llvm.org/rGcdd683b516d147925212724b09ec6fb792a40041 Link: https://reviews.llvm.org/rG13a633b438b6500ecad9e4f936ebadf3411d0f44 Link: https://lkml.kernel.org/r/20210312224132.3413602-2-ndesaulniers@google.com Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Reported-by: Prasad Sodagudi <psodagud@quicinc.com> Suggested-by: Nathan Chancellor <nathan@kernel.org> Reviewed-by: Fangrui Song <maskray@google.com> Tested-by: Nathan Chancellor <nathan@kernel.org> Acked-by: Peter Oberparleiter <oberpar@linux.ibm.com> Reviewed-by: Nathan Chancellor <nathan@kernel.org> Cc: <stable@vger.kernel.org> [5.4+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* gcov: clang supportGreg Hackmann2019-05-141-0/+581
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>