Added compile-time define to gate "initial-exec" attribute.

The "initial-exec" attribute is added to the ThreadCache::threadlocal_heap_
variable under normal compilation. This causes the linker to emit a
R_X86_64_TPOFF64 relocation in the _pyautolib.so shared object. This relocation
can cause python to error with:

cannot allocate memory in static TLS block

when it calls dlopen() on _pyautolib.so (when the import statement is
interpreted).

This only happens when the TLS section is large enough. Building Chrome with
-fprofile-generate to add some instrumentation-related data to the TLS is enough
to trigger this condition.

This CL encloses the function attribute in #if ! defined(PGO_GENERATE). When
Chrome is built with -fprofile-generate, we will also pass in -DPGO_GENERATE and
-ftls-model=global-dynamic so profile data can be collected without any errors.

BUG=none
TEST=Rebuilt chromeos-chrome in the chroot with -fprofile-generate
-ftls-model=global-dynamic -DPGO_GENERATE && ran pyautoperf autotests.


Review URL: http://codereview.chromium.org/10035012

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@133810 0039d316-1c4b-4281-b951-d872f2087c98

0 files changed, 0 insertions, 0 deletions