[compiler-rt] Avoid instrumenting sanitizer functions

Summary:
Function __asan_default_options is called by __asan_init before the
shadow memory got initialized. Instrumenting that function may lead
to flaky execution.

As the __asan_default_options is provided by users, we cannot expect
them to add the appropriate function atttributes to avoid
instrumentation.

Reviewers: kcc, rnk

Subscribers: dberris, chrisha, llvm-commits

Differential Revision: https://reviews.llvm.org/D24566

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@281503 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed