allow_posix_link_time_opt and is_cfi are clang features

build/toolchain/toolchain.gni

 # Copyright 2015 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.
 
 # Toolchain-related configuration that may be needed outside the context of the
 # toolchain() rules themselves.
 
 import("//build_overrides/build.gni")
 import("//build/config/chrome_build.gni")
 
 declare_args() {
   # Enable Link Time Optimization in optimized builds (output programs run
   # faster, but linking is up to 5-20x slower).
   # Note: use target_os == "linux" rather than is_linux so that it does not
   # apply to host_toolchain when target_os="android".
-  allow_posix_link_time_opt = target_os == "linux" && !is_chromeos &&
-                              target_cpu == "x64" && is_official_build
+  allow_posix_link_time_opt =
+      is_clang && target_os == "linux" && !is_chromeos && target_cpu == "x64" &&
+      is_official_build
 
   # Set to true to use lld, the LLVM linker. This flag may be used on Windows
   # with the shipped LLVM toolchain, or on Linux with a self-built top-of-tree
   # LLVM toolchain (see llvm_force_head_revision in
   # build/config/compiler/BUILD.gn).
   use_lld = is_win && host_os != "win"
 
   # If used with allow_posix_link_time_opt, it enables the experimental support
   # of ThinLTO that links 3x-10x faster but (as of now) does not have all the
   # important optimizations such us devirtualization implemented. See also
@@ skipping 78 matching lines @@
   _tool_wrapper_path =
       rebase_path("//build/toolchain/win/tool_wrapper.py", root_build_dir)
 
   stamp_command = "$python_path $_tool_wrapper_path stamp {{output}}"
   copy_command =
       "$python_path $_tool_wrapper_path recursive-mirror {{source}} {{output}}"
 } else {
   stamp_command = "touch {{output}}"
   copy_command = "ln -f {{source}} {{output}} 2>/dev/null || (rm -rf {{output}} && cp -af {{source}} {{output}})"
 }