Ehsan, can you quickly explain, why this is not supported yet by clang-cl? I thought, clang-cl and clang will link the same ASan runtime library, and I think all the __asan_default_options thing does is tell the ASan runtime library which default options are used. It's not some extra magic done in Clang, it's just used in compiler-rt. Otherwise, the patch looks fine to me, if we need it :)

Comment on attachment 8452837 [details] [diff] [review] Do not use __asan_default_options with clang-cl because it is not supported yet Nevermind, I think I found out from the source that weak functions/attributes don't work on Windows and therefore they disabled __asan_default_options, as it's a weak function.

Yeah. Also, note that most of the compiler-rt support for ASAN on clang-cl code is code that is not shared with the Linux/OSX one. We probably need to fix this at some point, but for now I'm more interested in getting to _a_ build. :-) https://hg.mozilla.org/integration/mozilla-inbound/rev/756dae0c26b2

Yep, I fully agree. And as a workaround we can set these options at runtime until we have a solution.