GN: Build with a custom libc++ when using ASAN, TSAN or MSAN.

build/config/sanitizers/BUILD.gn

 # Copyright 2014 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/sanitizers/sanitizers.gni")
+
 # Contains the dependencies needed for sanitizers to link into executables and
 # shared_libraries. Unconditionally depend upon this target as it is empty if
 # |is_asan|, |is_lsan|, |is_tsan| and |is_msan| are false.

[earthdok, 2015/05/26 16:43:49]

This comment needs to be updated.

By the way, where is this unconditional dependency declared? The only candidate
I see is in ./build/config/BUILDCONFIG.gn, but that seems to only affect
component builds.

[Sam McNally, 2015/05/27 00:08:15]

Done.
Executables and shared libraries should have a dependency on this target. See
https://code.google.com/p/chromium/codesearch/#search/&q=sanitizers:deps

 group("deps") {
   deps = [
     "//third_party/instrumented_libraries:deps",
   ]
   if (is_asan || is_lsan || is_tsan || is_msan) {
     public_configs = [ ":sanitizer_options_link_helper" ]
     deps += [ ":options_sources" ]
   }
+  if (use_custom_libcxx) {
+    deps += [ "//buildtools/third_party/libc++:libcxx_proxy" ]
+  }
 }
 
 config("sanitizer_options_link_helper") {
   ldflags = [ "-Wl,-u_sanitizer_options_link_helper" ]
   if (is_asan) {
     ldflags += [ "-fsanitize=address" ]
   }
   if (is_lsan) {
     ldflags += [ "-fsanitize=leak" ]
   }
@@ skipping 19 matching lines @@
   }
 
   if (is_lsan) {
     sources += [ "//build/sanitizers/lsan_suppressions.cc" ]
   }
 
   if (is_tsan) {
     sources += [ "//build/sanitizers/tsan_suppressions.cc" ]
   }
 }