GN: Add support for prebuilt instrumented libraries.

build/config/compiler/BUILD.gn

 # Copyright (c) 2013 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import("//build/config/android/config.gni")
 import("//build/config/chrome_build.gni")
 if (current_cpu == "arm") {
   import("//build/config/arm.gni")
 }
 if (current_cpu == "mipsel" || current_cpu == "mips64el") {
   import("//build/config/mips.gni")
 }
 if (is_posix) {
   import("//build/config/gcc/gcc_version.gni")
 }
 
 import("//build/toolchain/ccache.gni")
+import("//build/config/sanitizers/sanitizers.gni")
 
 declare_args() {
   # Normally, Android builds are lightly optimized, even for debug builds, to
   # keep binary size down. Setting this flag to true disables such optimization
   android_full_debug = false
 
   # Whether to use the binary binutils checked into third_party/binutils.
   # These are not multi-arch so cannot be used except on x86 and x86-64 (the
   # only two architectures that are currently checked in). Turn this off when
   # you are using a custom toolchain and need to control -B in cflags.
@@ skipping 21 matching lines @@
   # http://gcc.gnu.org/wiki/DebugFission
   use_debug_fission =
       !is_win && use_gold && linux_use_bundled_binutils && !use_ccache
 
   if (is_win) {
     # Whether the VS xtree header has been patched to disable warning 4702. If
     # it has, then we don't need to disable 4702 (unreachable code warning).
     # The patch is preapplied to the internal toolchain and hence all bots.
     msvs_xtree_patched = false
   }
-
-  # 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 = 2
 }
 
 # default_include_dirs ---------------------------------------------------------
 #
 # This is a separate config so that third_party code (which would not use the
 # source root and might have conflicting versions of some headers) can remove
 # this and specify their own include paths.
 config("default_include_dirs") {
   include_dirs = [
     "//",
@@ skipping 94 matching lines @@
     }
     if (is_msan) {
       msan_blacklist_path =
           rebase_path("//tools/msan/blacklist.txt", root_build_dir)
       cflags += [
         "-fsanitize=memory",
         "-fsanitize-memory-track-origins=$msan_track_origins",
         "-fsanitize-blacklist=$msan_blacklist_path",
       ]
 
-      # TODO(GYP): Support instrumented libraries and custom libc++.

[earthdok, 2015/05/28 18:27:45]

This isn't resolved. We need to support source builds in addition to binary
downloads.

It probably makes sense to decouple source builds from Chromium's build system
completely and support them only as a way to produce pre-built binaries for GCS.
But one way or another, this must be resolved before GYP builds stop working.

[Sam McNally, 2015/05/29 08:33:00]

Moved the TODO into the instrumented_libraries BUILD.gn.

+      # TODO(GYP): Support custom libc++.
     }
   }
 
   if (is_clang && is_debug) {
     # Allow comparing the address of references and 'this' against 0
     # in debug builds. Technically, these can never be null in
     # well-defined C/C++ and Clang can optimize such checks away in
     # release builds, but they may be used in asserts in debug builds.
     cflags_cc += [
       "-Wno-undefined-bool-conversion",
@@ skipping 954 matching lines @@
       cflags += [ "-gsplit-dwarf" ]
     }
   }
 }
 
 config("no_symbols") {
   if (!is_win) {
     cflags = [ "-g0" ]
   }
 }