[test] Make msan work for v8 stand-alone.

build/standalone.gypi

Index: build/standalone.gypi
diff --git a/build/standalone.gypi b/build/standalone.gypi
index ee91e78899f0b9d726e10c978d89be49fdb98c88..98fe7c7fa94e7917935a3b61ca67c35bfbf07819 100644
--- a/build/standalone.gypi
+++ b/build/standalone.gypi
@@ -36,6 +36,11 @@
     'make_clang_dir%': '../third_party/llvm-build/Release+Asserts',
     'clang_xcode%': 0,
     'asan%': 0,
+    'msan%': 0,
+    # Track where uninitialized memory originates from. From fastest to
+    # slowest: 0 - no tracking, 1 - track only the initial allocation site, 2
+    # - track the chain of stores leading from allocation site to use site.
+    'msan_track_origins%': 1,
     'tsan%': 0,
     'visibility%': 'hidden',
     'v8_enable_backtrace%': 0,
@@ -201,34 +206,60 @@
     ],
   },
   'conditions': [
-    ['asan==1', {
+    ['asan==1 or msan==1 or tsan==1', {
       'target_defaults': {
         'cflags_cc+': [
           '-fno-omit-frame-pointer',
           '-gline-tables-only',
-          '-fsanitize=address',
-          '-w',  # http://crbug.com/162783
         ],
         'cflags_cc!': [
           '-fomit-frame-pointer',
         ],
         'ldflags': [
+          # Functions interposed by the sanitizers can make ld think
+          # that some libraries aren't needed when they actually are,
+          # http://crbug.com/234010. As workaround, disable --as-needed.
+          '-Wl,--as-needed',

[earthdok, 2014/12/19 15:54:02]

this should be in "ldflags!", not "ldflags"

+        ],
+        'dependencies': [
+          # Use libc++ (third_party/libc++ and third_party/libc++abi) instead of
+          # stdlibc++ as standard library. This is intended to use for instrumented
+          # builds.
+          '<(DEPTH)/third_party/libc++/libc++.gyp:libcxx_proxy',
+        ],
+      },
+    }],
+    ['asan==1', {
+      'target_defaults': {
+        'cflags_cc+': [
+          '-fsanitize=address',
+        ],
+        'ldflags': [
           '-fsanitize=address',
         ],
       },
     }],
+    ['msan==1', {
+      'target_defaults': {
+        'cflags_cc+': [
+          '-fsanitize=memory',
+          '-fsanitize-memory-track-origins=<(msan_track_origins)',
+        ],
+        'ldflags': [
+          '-fsanitize=memory',
+        ],
+        'defines': [
+          'MEMORY_SANITIZER',
+        ],
+      },
+    }],
     ['tsan==1', {
       'target_defaults': {
         'cflags+': [
-          '-fno-omit-frame-pointer',
-          '-gline-tables-only',
           '-fsanitize=thread',
           '-fPIC',
           '-Wno-c++11-extensions',
         ],
-        'cflags!': [
-          '-fomit-frame-pointer',
-        ],
         'ldflags': [
           '-fsanitize=thread',
           '-pie',