build/toolchain/clang.gni

# Copyright (c) 2013 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.

if (is_mac || is_ios) {
  import("//build/config/ios/ios_sdk.gni") # For use_ios_simulator
}

declare_args() {
  # Enable the optional type profiler in Clang, which will tag heap allocations
  # with the allocation type.
  use_clang_type_profiler = false

  # Enable Link Time Optimzations. This significantly slows down linking but
  # results in a smaller binary.
  enable_lto = true

  # Generate code with instrumentation for code coverage generation using LLVM.
  enable_coverage = false

  # Set this flag to enable bitcode. Only valid for iOS ARM builds.
  enable_bitcode = false

  # Set this flag to cause bitcode to be marker only.
  bitcode_marker = false

  # Set this flag to strip .so files.
  stripped_symbols = !is_debug
}

declare_args() {
  # The version of Xcode used to archive a release application with embedded
  # bitcode must be greater than or equal to the version of the toolchain
  # that created the bitcode in Flutter.framework. This means that when we build
  # the framework with embedded bitcode, we must use the Xcode toolchain and
  # its version must be less than or equal to what we expect our developers to be using.
  # Unfortunately, using the Xcode toolchain is not compatible with GOMA.
  #
  # The failure mode for this arises when a developer attempts to archive an application
  # for publication to the store with embedded bitcode.
  #
  # Since we do not support publishing debug or profile builds, we use 
  # bitcode_marker which is intrinsically faster to build and does not introduce
  # compatibility concerns between toolchains, meaning we can use
  # a GOMA enabled Clang.
  #
  # TODO(gw280): Once our own copy of clang 12 is capable of building for arm64 simulator,
  # we can safely remove the requirement that we use xcode for arm64 simulator builds.
  if (is_mac || is_ios) {
    use_xcode = (enable_bitcode && !bitcode_marker) || (use_ios_simulator && target_cpu == "arm64")
  } else {
    use_xcode = false
  }
}