Add msan build option.

Add msan build option.

Currently works only in combination with i18nsupport=off.

R=jkummerow@chromium.org

Committed: https://code.google.com/p/v8/source/detail?r=22109

[Jakob Kummerow, 2014-07-01 08:55:54]

lgtm

[Yang, 2014-07-01 09:04:54]

Committed patchset #2 manually as r22109 (tree was closed).

[earthdok, 2014-07-01 12:13:22]

We need the following flags as well:

cflags: -gline-tables-only (in Release), -fPIC, -DMEMORY_SANITIZER

ldflags: -pie (in executables)

https://codereview.chromium.org/367623002/diff/20001/Makefile
File Makefile (right):

https://codereview.chromium.org/367623002/diff/20001/Makefile#newcode150
Makefile:150: GYPFLAGS += -Dmsan=1 -Dmsan_track_origins=2
You set msan_track_origins here but you don't use that variable in the GYP file.
The GYP file should pass something like
-fsanitize-memory-track-origins=<(msan_track_origins).

Also, as said in the other comment, please reconsider hardcoding this to 2.

https://codereview.chromium.org/367623002/diff/20001/build/standalone.gypi
File build/standalone.gypi (right):

https://codereview.chromium.org/367623002/diff/20001/build/standalone.gypi#ne...
build/standalone.gypi:193: '-fsanitize-memory-track-origins=2',
-fsanitize-memory-track-origins can take values from 0 (fastest, least amount of
information) to 2 (slowest, most helpful reports, experimental). Please expose
this setting rather than hardcode it to 2.

https://codereview.chromium.org/367623002/diff/20001/build/standalone.gypi#ne...
build/standalone.gypi:195: '-w',  # http://crbug.com/162783
The linked issue refers to ASan, not MSan. We don't use -w with MSan in Chrome
and shouldn't need it for V8, either.

[earthdok, 2014-07-01 12:22:02]

As I noted on the email thread, we won't be able to use this without an
instrumented libc++.

[Yang, 2014-07-01 14:55:56]

On 2014/07/01 12:22:02, earthdok wrote:
> As I noted on the email thread, we won't be able to use this without an
> instrumented libc++.

For posterity, this got reverted in r22124.