Add msan build option.

Makefile

 # Copyright 2012 the V8 project authors. All rights reserved.
 # Redistribution and use in source and binary forms, with or without
 # modification, are permitted provided that the following conditions are
 # met:
 #
 #     * Redistributions of source code must retain the above copyright
 #       notice, this list of conditions and the following disclaimer.
 #     * Redistributions in binary form must reproduce the above
 #       copyright notice, this list of conditions and the following
 #       disclaimer in the documentation and/or other materials provided
@@ skipping 127 matching lines @@
   GYPFLAGS += -Dv8_deprecation_warnings=1
 endif
 # asan=/path/to/clang++
 ifneq ($(strip $(asan)),)
   GYPFLAGS += -Dasan=1
   export CXX=$(asan)
   export CXX_host=$(asan)
   export LINK=$(asan)
   export ASAN_SYMBOLIZER_PATH="$(dir $(asan))llvm-symbolizer"
 endif
-
+# msan=/path/to/clang++
+ifneq ($(strip $(msan)),)
+  GYPFLAGS += -Dmsan=1 -Dmsan_track_origins=2

[earthdok, 2014/07/01 12:13:21]

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.

+  export CXX=$(msan)
+  export CXX_host=$(msan)
+  export LINK=$(msan)
+endif
 # arm specific flags.
 # arm_version=<number | "default">
 ifneq ($(strip $(arm_version)),)
   GYPFLAGS += -Darm_version=$(arm_version)
 else
 # Deprecated (use arm_version instead): armv7=false/true
 ifeq ($(armv7), false)
   GYPFLAGS += -Darm_version=6
 else
 ifeq ($(armv7), true)
@@ skipping 305 matching lines @@
 # Dependencies.
 # Remember to keep these in sync with the DEPS file.
 dependencies:
         svn checkout --force http://gyp.googlecode.com/svn/trunk build/gyp \
             --revision 1831
         svn checkout --force \
             https://src.chromium.org/chrome/trunk/deps/third_party/icu46 \
             third_party/icu --revision 258359
         # The spec is a copy of the hooks in v8's DEPS file.
         gclient sync -r fb782d4369d5ae04f17a2fceef7de5a63e50f07b --spec="solutions = [{u'managed': False, u'name': u'buildtools', u'url': u'https://chromium.googlesource.com/chromium/buildtools.git', u'custom_deps': {}, u'custom_hooks': [{u'name': u'clang_format_win',u'pattern': u'.',u'action': [u'download_from_google_storage',u'--no_resume',u'--platform=win32',u'--no_auth',u'--bucket',u'chromium-clang-format',u'-s',u'buildtools/win/clang-format.exe.sha1']},{u'name': u'clang_format_mac',u'pattern': u'.',u'action': [u'download_from_google_storage',u'--no_resume',u'--platform=darwin',u'--no_auth',u'--bucket',u'chromium-clang-format',u'-s',u'buildtools/mac/clang-format.sha1']},{u'name': u'clang_format_linux',u'pattern': u'.',u'action': [u'download_from_google_storage',u'--no_resume',u'--platform=linux*',u'--no_auth',u'--bucket',u'chromium-clang-format',u'-s',u'buildtools/linux64/clang-format.sha1']}],u'deps_file': u'.DEPS.git', u'safesync_url': u''}]"