Implement clang tool that converts std::string("") to std::string().

tools/clang/scripts/update.sh

 #!/usr/bin/env bash
 # Copyright (c) 2012 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.
 
 # This script will check out llvm and clang into third_party/llvm and build it.
 
 # Do NOT CHANGE this if you don't know what you're doing -- see
 # https://code.google.com/p/chromium/wiki/UpdatingClang
 # Reverting problematic clang rolls is safe, though.
@@ skipping 22 matching lines @@
 # Parse command line options.
 force_local_build=
 mac_only=
 run_tests=
 bootstrap=
 with_android=yes
 # Temporary workaround for http://crbug.com/170629: use older Clang for ASan
 # Mac builders.
 is_asan_mac_builder_hackfix=
 with_tools_extra=
+chrome_tools="plugins"
+
 if [[ "${OS}" = "Darwin" ]]; then
   with_android=
 fi
 
 while [[ $# > 0 ]]; do
   case $1 in
     --bootstrap)
       bootstrap=yes
       ;;
     --force-local-build)
       force_local_build=yes
       ;;
     --mac-only)
       mac_only=yes
       ;;
     --run-tests)
       run_tests=yes
       ;;
     --without-android)
       with_android=
       ;;
     # Temporary workaround for http://crbug.com/170629 - use older Clang for
     # ASan Mac builders.
     --is-asan-mac-builder-hackfix)
       is_asan_mac_builder_hackfix=yes
       ;;
     --with-tools-extra)
       with_tools_extra=yes
       ;;
+    --with-chrome-tools)
+      shift
+      if [[ $# == 0 ]]; then
+        echo "--with-chrome-tools requires an argument."
+        exit 1
+      fi
+      chrome_tools=$1
+      ;;
     --help)
       echo "usage: $0 [--force-local-build] [--mac-only] [--run-tests] "
       echo "--bootstrap: First build clang with CC, then with itself."
       echo "--force-local-build: Don't try to download prebuilt binaries."
       echo "--mac-only: Do initial download only on Mac systems."
       echo "--run-tests: Run tests after building. Only for local builds."
       echo "--without-android: Don't build ASan Android runtime library."
       echo "--is-asan-mac-builder-hackfix: Use older Clang" \
            "to build ASan on Mac."
       echo "--with-tools-extra: Also build the clang-tools-extra repository."
+      echo "--with-chrome-tools: Select which chrome tools to build." \
+           "Defaults to plugins."
+      echo "    Example: --with-chrome-tools 'plugins empty-string'"
+      echo
       exit 1
       ;;
   esac
   shift
 done
 
 # Are we on a Chrome buildbot running ASan?
 function on_asan_mac_host {
   if [[ "${OS}" != "Darwin" ]]; then
     return 1
@@ skipping 276 matching lines @@
   fi
 
   # Build ASan runtime for Android.
   cd "${LLVM_BUILD_DIR}"
   make -C tools/clang/runtime/ LLVM_ANDROID_TOOLCHAIN_DIR="../../../../${TC}"
   cd -
 fi
 
 # Build Chrome-specific clang tools. Paths in this list should be relative to
 # tools/clang.
-CHROME_TOOL_DIRS="plugins"
 # For each tool directory, copy it into the clang tree and use clang's build
 # system to compile it.
-for CHROME_TOOL_DIR in ${CHROME_TOOL_DIRS}; do
+for CHROME_TOOL_DIR in ${chrome_tools}; do
   TOOL_SRC_DIR="${THIS_DIR}/../${CHROME_TOOL_DIR}"
   TOOL_DST_DIR="${LLVM_DIR}/tools/clang/tools/chrome-${CHROME_TOOL_DIR}"
   TOOL_BUILD_DIR="${LLVM_BUILD_DIR}/tools/clang/tools/chrome-${CHROME_TOOL_DIR}"
   rm -rf "${TOOL_DST_DIR}"
   cp -R "${TOOL_SRC_DIR}" "${TOOL_DST_DIR}"
   rm -rf "${TOOL_BUILD_DIR}"
   mkdir -p "${TOOL_BUILD_DIR}"
   cp "${TOOL_SRC_DIR}/Makefile" "${TOOL_BUILD_DIR}"
   MACOSX_DEPLOYMENT_TARGET=10.5 make -j"${NUM_JOBS}" -C "${TOOL_BUILD_DIR}"
 done
 
 if [[ -n "$run_tests" ]]; then
   # Run a few tests.
   PLUGIN_SRC_DIR="${THIS_DIR}/../plugins"
   "${PLUGIN_SRC_DIR}/tests/test.sh" "${LLVM_BUILD_DIR}/Release+Asserts"
   cd "${LLVM_BUILD_DIR}"
   make check-all
   cd -
 fi
 
 # After everything is done, log success for this revision.
 echo "${CLANG_REVISION}" > "${STAMP_FILE}"