Fix removal of unreferenced ASAN API functions

Fix removal of unreferenced ASAN API functions

When a DLL is instrumented with ASAN, there is some thunks introduced
that dynamically resolved the function through the imports table and
redirect the call from the DLL to the main executable.

Unfortunately, unreferenced functions recently got removed by the
linker.

Without this fix this function is not part of the final executable:
  __asan_locate_address

  % dumpbin D:\src\chromium\src\out\ninja64\initialexe\chrome.exe /exports | grep asan_l

This is making chrome to crash on startup when loading chrome_elf.dll.
ASAN is failing to hook on a function and call abort, which is also
failing because ASAN is still in the "tls-initialisation" phase.

R=ochang@chromium.org, rnk@chromium.org, thakis@chromium.org, chrisha@chromium.org
BUG=

Review-Url: https://codereview.chromium.org/2710573003
Cr-Commit-Position: refs/heads/master@{#451836}
Committed: https://chromium.googlesource.com/chromium/src/+/803397e04777bc734a9c028813351c2e5079faf1

[etienneb, 2017-02-21 15:53:17]

Description was changed from

==========
Fix removal of unreferenced ASAN API functions

When a DLL is instrumented with ASAN, there is some thunks introduced
that dynamically resolved the function through the imports table and
redirect the call from the DLL to the main executable.

Unfortunately, unreferenced functions recently got removed by the
linker.

This is making chrome to crash on startup when loading chrome_elf.dll.
ASAN is failing to hook on a function and call abort, which is also
failing because ASAN is still in the "tls-initialisation" phase.

R=ochang@chromium.org, rnk@chromium.org, thakis@chromium.org,
chrisha@chromium.org
BUG=
==========

to

==========
Fix removal of unreferenced ASAN API functions

When a DLL is instrumented with ASAN, there is some thunks introduced
that dynamically resolved the function through the imports table and
redirect the call from the DLL to the main executable.

Unfortunately, unreferenced functions recently got removed by the
linker.

Without this fix this function is not part of the final executable:
  __asan_locate_address

  % dumpbin D:\src\chromium\src\out\ninja64\initialexe\chrome.exe /exports |
grep asan_l

This is making chrome to crash on startup when loading chrome_elf.dll.
ASAN is failing to hook on a function and call abort, which is also
failing because ASAN is still in the "tls-initialisation" phase.

R=ochang@chromium.org, rnk@chromium.org, thakis@chromium.org,
chrisha@chromium.org
BUG=
==========

[etienneb, 2017-02-21 15:53:51]

PTAL & CQ

[Oliver Chang, 2017-02-21 17:49:08]

lgtm

[etienneb, 2017-02-21 18:30:31]

The CQ bit was checked by etienneb@chromium.org

[commit-bot: I haz the power, 2017-02-21 18:31:30]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2017-02-21 21:27:41]

CQ is committing da patch.

Bot data: {"patchset_id": 1, "attempt_start_ts": 1487701831260730, "parent_rev":
"0141c2d4feb310a2df117da00e8d920245187ef0", "commit_rev":
"803397e04777bc734a9c028813351c2e5079faf1"}

[commit-bot: I haz the power, 2017-02-21 21:28:47]

Description was changed from

==========
Fix removal of unreferenced ASAN API functions

When a DLL is instrumented with ASAN, there is some thunks introduced
that dynamically resolved the function through the imports table and
redirect the call from the DLL to the main executable.

Unfortunately, unreferenced functions recently got removed by the
linker.

Without this fix this function is not part of the final executable:
  __asan_locate_address

  % dumpbin D:\src\chromium\src\out\ninja64\initialexe\chrome.exe /exports |
grep asan_l

This is making chrome to crash on startup when loading chrome_elf.dll.
ASAN is failing to hook on a function and call abort, which is also
failing because ASAN is still in the "tls-initialisation" phase.

R=ochang@chromium.org, rnk@chromium.org, thakis@chromium.org,
chrisha@chromium.org
BUG=
==========

to

==========
Fix removal of unreferenced ASAN API functions

When a DLL is instrumented with ASAN, there is some thunks introduced
that dynamically resolved the function through the imports table and
redirect the call from the DLL to the main executable.

Unfortunately, unreferenced functions recently got removed by the
linker.

Without this fix this function is not part of the final executable:
  __asan_locate_address

  % dumpbin D:\src\chromium\src\out\ninja64\initialexe\chrome.exe /exports |
grep asan_l

This is making chrome to crash on startup when loading chrome_elf.dll.
ASAN is failing to hook on a function and call abort, which is also
failing because ASAN is still in the "tls-initialisation" phase.

R=ochang@chromium.org, rnk@chromium.org, thakis@chromium.org,
chrisha@chromium.org
BUG=

Review-Url: https://codereview.chromium.org/2710573003
Cr-Commit-Position: refs/heads/master@{#451836}
Committed:
https://chromium.googlesource.com/chromium/src/+/803397e04777bc734a9c02881335...
==========

[commit-bot: I haz the power, 2017-02-21 21:28:48]

Committed patchset #1 (id:1) as
https://chromium.googlesource.com/chromium/src/+/803397e04777bc734a9c02881335...

[Nico, 2017-02-21 21:31:34]

Hm, it seems kind of unfortunate that asan clients need to know about this.
Since links don't go through the compiler driver on windows, I can't think of
any way to prevent that though :-/