tcmalloc: Switch thread-safety annotations to support clang

tcmalloc contains its own copy of thread_annotations.h, wrapper
macros for static thread-safety analysis expressions. These thread-
safety expressions allow asserting (at compile time) that certain
locks are held or excluded or certain data is protected by specific
locks; they are checked at compile-time by recent versions of clang
or an old gcc branch (https://gcc.gnu.org/wiki/ThreadSafetyAnnotation).

Convert the #if-guard and macro names from the no-longer-supported
gcc branch's defines & macros to the versions supported by recent
versions of clang. This will allow us to (re-)enable these checks
in Chromium's fork of tcmalloc.

Also see: https://github.com/gperftools/gperftools/pull/1251

Change-Id: I9217d0f4718ba82697e0d8c8096baa390f98edbe
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2702729
Reviewed-by: Primiano Tucci <primiano@chromium.org>
Commit-Queue: Venkatesh Srinivas <venkateshs@chromium.org>
Cr-Commit-Position: refs/heads/master@{#856306}
GitOrigin-RevId: e0dedfa0d88dcf40d69b0f7a2f96a3ac66c209e7
1 file changed
tree: 5b80e1b00aa1d31aab81ee9c9b1938c455bcc5b6
  1. src/