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# 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 =
is_clang && target_os == "linux" && !is_chromeos && target_cpu == "x64" &&
is_official_build
# 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
# http://blog.llvm.org/2016/06/thinlto-scalable-and-incremental-lto.html
use_thin_lto = false
# If this is set to true, or if LLVM_FORCE_HEAD_REVISION is set to 1
# in the environment, we use the revision in the llvm repo to determine
# the CLANG_REVISION to use, instead of the version hard-coded into
# //tools/clang/scripts/update.py. This should only be used in
# conjunction with setting LLVM_FORCE_HEAD_REVISION in the
# environment when `gclient runhooks` is run as well.
llvm_force_head_revision = false
# Compile with Xcode version of clang instead of hermetic version shipped
# with the build. Used on iOS to ship official builds (as they are built
# with the version of clang shipped with Xcode).
use_xcode_clang = is_ios && is_official_build
# Used for binary size analysis.
# Currently disabled on LLD because of a bug (fixed upstream).
# See https://crbug.com/716209.
generate_linker_map = is_android && is_official_build
}
if (generate_linker_map) {
assert(
is_official_build,
"Linker map files should only be generated when is_official_build = true")
assert(target_os == "android" || target_os == "linux",
"Linker map files should only be generated for Android and Linux")
}
# The path to the hermetic install of Xcode. Only relevant when
# use_system_xcode = false.
hermetic_xcode_path =
rebase_path("//build/${target_os}_files/Xcode.app", "", root_build_dir)
declare_args() {
if (is_clang) {
# Clang compiler version. Clang files are placed at version-dependent paths.
clang_version = "5.0.0"
}
# Set to true to use lld, the LLVM linker. This flag may be used on Windows
# or Linux.
use_lld = (is_win && host_os != "win") ||
(allow_posix_link_time_opt && target_os == "linux" &&
!is_chromeos && target_cpu == "x64")
}
# Check target_os here instead of is_ios as this file is loaded for secondary
# toolchain (host toolchain in particular) but the argument is the same for
# all toolchains.
assert(!use_xcode_clang || target_os == "ios",
"Using Xcode's clang is only supported in iOS builds")
# Subdirectory within root_out_dir for shared library files.
# TODO(agrieve): GYP sets this to "lib" for Linux & Android, but this won't work
# in GN until support for loadable_module() is added.
# See: https://codereview.chromium.org/1236503002/
shlib_subdir = "."
# Root out dir for shared library files.
root_shlib_dir = root_out_dir
if (shlib_subdir != ".") {
root_shlib_dir += "/$shlib_subdir"
}
# Extension for shared library files (including leading dot).
if (is_mac || is_ios) {
shlib_extension = ".dylib"
} else if (is_android && is_component_build) {
# By appending .cr, we prevent name collisions with libraries already
# loaded by the Android zygote.
shlib_extension = ".cr.so"
} else if (is_posix) {
shlib_extension = ".so"
} else if (is_win) {
shlib_extension = ".dll"
} else {
assert(false, "Platform not supported")
}
# Prefix for shared library files.
if (is_posix) {
shlib_prefix = "lib"
} else {
shlib_prefix = ""
}
# While other "tool"s in a toolchain are specific to the target of that
# toolchain, the "stamp" and "copy" tools are really generic to the host;
# but each toolchain must define them separately. GN doesn't allow a
# template instantiation inside a toolchain definition, so some boilerplate
# has to be repeated in each toolchain to define these two tools. These
# four variables reduce the duplication in that boilerplate.
stamp_description = "STAMP {{output}}"
copy_description = "COPY {{source}} {{output}}"
if (host_os == "win") {
_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}})"
}
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