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author | Vedant Kumar <vsk@apple.com> | 2017-06-29 17:42:24 +0000 |
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committer | Vedant Kumar <vsk@apple.com> | 2017-06-29 17:42:24 +0000 |
commit | 9bf4394e71e00bc967ee620b51ba17ead8d23dbc (patch) | |
tree | 3dccf36e9ad26ab03961703e1a7acdd17c8b7cd4 /lib/msan/msan_allocator.cc | |
parent | ac3a01da8065bc2245131f7e53359d3b84c3924d (diff) |
[profile] Move __llvm_profile_filename into a separate object
Users can specify the path a raw profile is written to by passing
-fprofile-instr-generate=<path>, but this functionality broke on Darwin
after __llvm_profile_filename was made weak [1], resulting in profiles
being written to "default.profraw" even when <path> is specified.
The situation is that instrumented programs provide a weak definition of
__llvm_profile_filename, which conflicts with a weak redefinition
provided by the profiling runtime.
The linker appears to pick the 'winning' definition arbitrarily: on
Darwin, it usually prefers the larger definition, which is probably why
the instrprof-override-filename.c test has been passing.
The fix is to move the runtime's definition into a separate object file
within the archive. This means that the linker won't "see" the runtime's
definition unless the user program has not provided one. I couldn't
think of a great way to test this other than to mimic the Darwin
failure: use -fprofile-instr-generate=<some-small-path>.
Testing: check-{clang,profile}, modified instrprof-override-filename.c.
[1] [Profile] deprecate __llvm_profile_override_default_filename
https://reviews.llvm.org/D22613
https://reviews.llvm.org/D22614
Differential Revision: https://reviews.llvm.org/D34797
git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@306710 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/msan/msan_allocator.cc')
0 files changed, 0 insertions, 0 deletions