Add Undefined Behaviour sanitizer support to GN.

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|, |is_msan| and |use_custom_libcxx| are false.
 group("deps") {
-  if (is_asan || is_lsan || is_tsan || is_msan) {
+  if (is_asan || is_lsan || is_tsan || is_msan || is_ubsan) {
     public_configs = [ ":sanitizer_options_link_helper" ]
     deps = [
       ":options_sources",
     ]
 
     if (use_prebuilt_instrumented_libraries) {
       deps += [ "//third_party/instrumented_libraries:deps" ]
     }
     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" ]
   }
   if (is_tsan) {
     ldflags += [ "-fsanitize=thread" ]
   }
   if (is_msan) {
     ldflags += [ "-fsanitize=memory" ]
   }
+  if (is_ubsan) {
+    ldflags += [ "-fsanitize=undefined" ]
+  }
 }
 
 source_set("options_sources") {
   visibility = [
     ":deps",
     "//:gn_visibility",
   ]
   sources = [
     "//build/sanitizers/sanitizer_options.cc",
   ]
@@ skipping 62 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",
       ]
     }
+    if (is_ubsan) {
+      ubsan_blacklist_path =
+          rebase_path("//tools/ubsan/blacklist.txt", root_build_dir)
+      cflags += [
+        # Yasm dies with an "Illegal instruction" error when bounds checking is
+        # enabled. See http://crbug.com/489901
+        # "-fsanitize=bounds",
+        "-fsanitize=float-divide-by-zero",
+        "-fsanitize=integer-divide-by-zero",
+        "-fsanitize=null",
+        "-fsanitize=object-size",
+        "-fsanitize=return",
+        "-fsanitize=returns-nonnull-attribute",
+        "-fsanitize=shift-exponent",
+        "-fsanitize=signed-integer-overflow",
+        "-fsanitize=unreachable",
+        "-fsanitize=vla-bound",
+        "-fsanitize-blacklist=$ubsan_blacklist_path",
+
+        # Employ the experimental PBQP register allocator to avoid slow
+        # compilation on files with too many basic blocks.
+        # See http://crbug.com/426271.
+        "-mllvm",
+        "-regalloc=pbqp",
+
+        # Speculatively use coalescing to slightly improve the code generated
+        # by PBQP regallocator. May increase compile time.
+        "-mllvm",
+        "-pbqp-coalescing",
+      ]
+    }
     if (is_cfi && !is_nacl) {
       cfi_blacklist_path =
           rebase_path("//tools/cfi/blacklist.txt", root_build_dir)
       cflags += [
         "-flto",
         "-fsanitize=cfi-vcall",
         "-fsanitize=cfi-derived-cast",
         "-fsanitize=cfi-unrelated-cast",
         "-fsanitize-blacklist=$cfi_blacklist_path",
       ]
@@ skipping 41 matching lines @@
 
     if (use_custom_libcxx) {
       cflags_cc += [ "-nostdinc++" ]
       include_dirs = [
         "//buildtools/third_party/libc++/trunk/include",
         "//buildtools/third_party/libc++abi/trunk/include",
       ]
     }
   }
 }