Separate out GN sanitizer flags.

build/config/sanitizers/BUILD.gn

Index: build/config/sanitizers/BUILD.gn
diff --git a/build/config/sanitizers/BUILD.gn b/build/config/sanitizers/BUILD.gn
index 319c272f2380e6a363ccf4d523d98c7477fc5472..65bdbe419fd407b0831dee47339f6e028a582e61 100644
--- a/build/config/sanitizers/BUILD.gn
+++ b/build/config/sanitizers/BUILD.gn
@@ -48,6 +48,11 @@ source_set("options_sources") {
     "//build/sanitizers/sanitizer_options.cc",
   ]
 
+  # Don't compile this target with any sanitizer code. It can be called from
+  # the sanitizer runtimes, so instrumenting these functions could cause
+  # recursive calls into the runtime if there is an error.
+  configs -= [ "//build/config/sanitizers:default_sanitizer_flags" ]
+
   if (is_asan) {
     sources += [ "//build/sanitizers/asan_suppressions.cc" ]
   }
@@ -60,3 +65,118 @@ source_set("options_sources") {
     sources += [ "//build/sanitizers/tsan_suppressions.cc" ]
   }
 }
+
+# This config is applied by default to all targets. It sets the compiler flags
+# for sanitizer usage, or, if no sanitizer is set, does nothing.
+#
+# This needs to be in a separate config so that targets can opt out of
+# sanitizers if they desire.
+config("default_sanitizer_flags") {
+  cflags = []
+  cflags_cc = []
+  ldflags = []
+  defines = []
+
+  # Only works on Posix-like platforms.
+  if (is_posix) {
+    # Common options for AddressSanitizer, LeakSanitizer, ThreadSanitizer,
+    # MemorySanitizer and non-official CFI builds.
+    if (using_sanitizer || (is_cfi && !is_official_build)) {
+      cflags += [
+        "-fno-omit-frame-pointer",
+        "-gline-tables-only",
+      ]
+    }
+    if (is_asan) {
+      asan_blacklist_path =
+          rebase_path("//tools/memory/asan/blacklist.txt", root_build_dir)
+      cflags += [
+        "-fsanitize=address",
+        "-fsanitize-blacklist=$asan_blacklist_path",
+      ]
+      if (is_mac) {
+        cflags += [ "-mllvm -asan-globals=0" ]  # http://crbug.com/352073
+        # TODO(GYP): deal with mac_bundles.
+      }
+    }
+    if (is_lsan) {
+      cflags += [ "-fsanitize=leak" ]
+    }
+    if (is_tsan) {
+      tsan_blacklist_path =
+          rebase_path("//tools/memory/tsan_v2/ignores.txt", root_build_dir)
+      cflags += [
+        "-fsanitize=thread",
+        "-fsanitize-blacklist=$tsan_blacklist_path",
+      ]
+    }
+    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_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",
+      ]
+      ldflags += [
+        "-flto",
+        "-fsanitize=cfi-vcall",
+        "-fsanitize=cfi-derived-cast",
+        "-fsanitize=cfi-unrelated-cast",
+      ]
+
+      # Apply a lower LTO optimization level in non-official builds.
+      if (!is_official_build) {
+        if (is_linux) {
+          ldflags += [ "-Wl,-plugin-opt,O1" ]
+        } else if (is_mac) {
+          ldflags += [ "-Wl,-mllvm,-O1" ]
+        }
+      }
+
+      # Work-around for http://openradar.appspot.com/20356002
+      if (is_mac) {
+        ldflags += [ "-Wl,-all_load" ]
+      }
+
+      # Without this flag, LTO produces a .text section that is larger
+      # than the maximum call displacement, preventing the linker from
+      # relocating calls (http://llvm.org/PR22999).
+      if (current_cpu == "arm") {
+        ldflags += [ "-Wl,-plugin-opt,-function-sections" ]
+      }
+
+      if (use_cfi_diag) {
+        cflags += [
+          "-fno-sanitize-trap=cfi",
+          "-fsanitize-recover=cfi",
+        ]
+        ldflags += [
+          "-fno-sanitize-trap=cfi",
+          "-fsanitize-recover=cfi",
+        ]
+      } else {
+        defines += [ "CFI_ENFORCEMENT" ]
+      }
+    }
+
+    if (use_custom_libcxx) {
+      cflags_cc += [ "-nostdinc++" ]
+      include_dirs = [
+        "//buildtools/third_party/libc++/trunk/include",
+        "//buildtools/third_party/libc++abi/trunk/include",
+      ]
+    }
+  }
+}