[PATCH] D48445: [sanitizer] Use "fast mmap" kernel flag for shadow memory on macOS 10.13.4+

[Dan Liew via Phabricator via llvm-commits]

delcypher added inline comments.


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Comment at: lib/sanitizer_common/sanitizer_posix_libcdep.cc:338
   if (fd == -1) flags |= MAP_ANON;
+  if (fd == -1 && use_xnu_fast_mmap) fd = kXnuFastMmapFd;
 
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Side note. This implementation will prevent the VM tag being set (see https://reviews.llvm.org/D49603 ) with fast mmap is being used. This needs to be fixed.


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Comment at: lib/sanitizer_common/sanitizer_posix_libcdep.cc:391
   if (fd == -1) flags |= MAP_ANON;
+  if (fd == -1 && use_xnu_fast_mmap) fd = kXnuFastMmapFd;
 
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delcypher wrote:
> Again can't we move this into the Darwin implementation of `internal_mmap()`. This will also mean we avoid duplicating code.
Side note. This implementation will prevent the VM tag being set (see https://reviews.llvm.org/D49603 ) with fast mmap is being used. This needs to be fixed.


Repository:
  rCRT Compiler Runtime

https://reviews.llvm.org/D48445