[PATCH] D39888: [lsan] Only use VM_MEMORY_OS_ALLOC_ONCE on Darwin versions that support it

[Rainer Orth via Phabricator via llvm-commits]

ro added a comment.

In https://reviews.llvm.org/D39888#924537, @dberris wrote:

> If I understand correctly, the check should happen at CMake configuration time, so that lsan doesn't even build for versions of OS X that aren't even supported.


That's what currently is happending for most of the lsan support in the gcc tree: it isn't build on Mac OS X at all, perhaps due to blocks
support missing in gcc.  OTOH, that is guarded with MISSING_BLOCKS_SUPPORT, so it might even work.

However, the code at hand is in the common part of lsan which (except for CAN_SANITIZE_LEAKS) is always compiled.

It should be possible to disable all of lsan by setting COMPILER_RT_HAS_LSAN in cmake/config-ix.cmake, but I've just failed
miserably doing that when trying to disable tsan for OS X < 10.9 in LLVM 3.9.1.


https://reviews.llvm.org/D39888