blob: 09af53d2f36329abe69e3c73d2324ab810d1a8c1 [file] [log] [blame]
# 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.
import("//build/config/clang/clang.gni")
import("//build/config/compiler/compiler.gni")
import("//build/config/coverage/coverage.gni")
import("//build/config/sanitizers/sanitizers.gni")
import("//build/config/v8_target_cpu.gni")
import("//build/toolchain/cc_wrapper.gni")
import("//build/toolchain/goma.gni")
import("//build/toolchain/rbe.gni")
import("//build/toolchain/toolchain.gni")
if (is_nacl) {
# To keep NaCl variables out of builds that don't include NaCl, all
# variables defined in nacl/config.gni referenced here should be protected by
# is_nacl conditions.
import("//build/config/nacl/config.gni")
}
declare_args() {
# Enables allowlist generation for IDR_ grit defines seen by the compiler.
# Currently works only on some platforms and enabled by default for official
# builds. Requires debug info.
enable_resource_allowlist_generation =
is_official_build &&
# Don't enable for Android-on-Chrome OS so that they can build with
# symbol_level=0 without this failing (crbug.com/891164).
(target_os == "android" || target_os == "win")
}
# When the arg is set via args.gn, it applies to all toolchains. In order to not
# hit the assert in grit_rule.gni, explicitly disable for host toolchains.
if ((is_linux || is_chromeos) && target_os == "android") {
enable_resource_allowlist_generation = false
}
# Ensure enable_resource_allowlist_generation is enabled only when it will work.
if (enable_resource_allowlist_generation) {
assert(symbol_level >= 1,
"enable_resource_allowlist_generation=true requires symbol_level >= 1")
assert(
!strip_debug_info,
"enable_resource_allowlist_generation=true requires strip_debug_info=false")
assert(
!is_component_build,
"enable_resource_allowlist_generation=true requires is_component_build=false")
assert(
target_os == "android" || target_os == "win",
"enable_resource_allowlist_generation=true does not work for target_os=$target_os")
}
# This template defines a toolchain for something that works like gcc
# (including clang).
#
# It requires the following variables specifying the executables to run:
# - ar
# - cc
# - cxx
# - ld
#
# Optional parameters that control the tools:
#
# - extra_cflags
# Extra flags to be appended when compiling C files (but not C++ files).
# - extra_cppflags
# Extra flags to be appended when compiling both C and C++ files. "CPP"
# stands for "C PreProcessor" in this context, although it can be
# used for non-preprocessor flags as well. Not to be confused with
# "CXX" (which follows).
# - extra_cxxflags
# Extra flags to be appended when compiling C++ files (but not C files).
# - extra_asmflags
# Extra flags to be appended when compiling assembly.
# - extra_ldflags
# Extra flags to be appended when linking
#
# - link_outputs
# The content of this array, if specified, will be added to the list of
# outputs from the link command. This can be useful in conjunction with
# the post_link parameter.
# - use_unstripped_as_runtime_outputs
# When |strip| is set, mark unstripped executables as runtime deps rather
# than stripped ones.
# - post_link
# The content of this string, if specified, will be run as a separate
# command following the the link command.
# - deps
# Just forwarded to the toolchain definition.
# - executable_extension
# If this string is specified it will be used for the file extension
# for an executable, rather than using no extension; targets will
# still be able to override the extension using the output_extension
# variable.
# - rebuild_define
# The contents of this string, if specified, will be passed as a #define
# to the toolchain. It can be used to force recompiles whenever a
# toolchain is updated.
# - shlib_extension
# If this string is specified it will be used for the file extension
# for a shared library, rather than default value specified in
# toolchain.gni
# - strip
# Location of the strip executable. When specified, strip will be run on
# all shared libraries and executables as they are built. The pre-stripped
# artifacts will be put in lib.unstripped/ and exe.unstripped/.
template("gcc_toolchain") {
toolchain(target_name) {
assert(defined(invoker.ar), "gcc_toolchain() must specify a \"ar\" value")
assert(defined(invoker.cc), "gcc_toolchain() must specify a \"cc\" value")
assert(defined(invoker.cxx), "gcc_toolchain() must specify a \"cxx\" value")
assert(defined(invoker.ld), "gcc_toolchain() must specify a \"ld\" value")
# This define changes when the toolchain changes, forcing a rebuild.
# Nothing should ever use this define.
if (defined(invoker.rebuild_define)) {
rebuild_string = "-D" + invoker.rebuild_define + " "
} else {
rebuild_string = ""
}
# GN's syntax can't handle more than one scope dereference at once, like
# "invoker.toolchain_args.foo", so make a temporary to hold the toolchain
# args so we can do "invoker_toolchain_args.foo".
assert(defined(invoker.toolchain_args),
"Toolchains must specify toolchain_args")
invoker_toolchain_args = invoker.toolchain_args
assert(is_starboard || defined(invoker_toolchain_args.current_cpu),
"toolchain_args must specify a current_cpu")
assert(is_starboard || defined(invoker_toolchain_args.current_os),
"toolchain_args must specify a current_os")
# When invoking this toolchain not as the default one, these args will be
# passed to the build. They are ignored when this is the default toolchain.
toolchain_args = {
# Populate toolchain args from the invoker.
forward_variables_from(invoker_toolchain_args, "*")
# The host toolchain value computed by the default toolchain's setup
# needs to be passed through unchanged to all secondary toolchains to
# ensure that it's always the same, regardless of the values that may be
# set on those toolchains.
if (!is_starboard) {
host_toolchain = host_toolchain
if (!defined(invoker_toolchain_args.v8_current_cpu)) {
v8_current_cpu = invoker_toolchain_args.current_cpu
}
}
}
# When the invoker has explicitly overridden user_rbe, use_goma or
# cc_wrapper in the toolchain args, use those values, otherwise default
# to the global one. This works because the only reasonable override
# that toolchains might supply for these values are to force-disable them.
if (defined(toolchain_args.use_rbe)) {
toolchain_uses_rbe = toolchain_args.use_rbe
} else {
toolchain_uses_rbe = use_rbe
}
if (defined(toolchain_args.use_goma)) {
toolchain_uses_goma = toolchain_args.use_goma
} else {
toolchain_uses_goma = use_goma
}
# x86_64-nacl-* is ELF-32 and Goma/RBE won't support ELF-32.
if (toolchain_uses_goma &&
get_path_info(invoker.cc, "name") == "x86_64-nacl-gcc") {
# it will also disable x86_64-nacl-g++ since these are in
# the same toolchain.
toolchain_uses_goma = false
}
if (defined(toolchain_args.cc_wrapper)) {
toolchain_cc_wrapper = toolchain_args.cc_wrapper
} else {
toolchain_cc_wrapper = cc_wrapper
}
assert(!(toolchain_uses_rbe && toolchain_uses_goma),
"Goma and RBE can't be used together.")
assert(!(toolchain_cc_wrapper != "" && toolchain_uses_rbe),
"RBE and cc_wrapper can't be used together.")
assert(!(toolchain_cc_wrapper != "" && toolchain_uses_goma),
"Goma and cc_wrapper can't be used together.")
# When the invoker has explicitly overridden use_goma or cc_wrapper in the
# toolchain args, use those values, otherwise default to the global one.
# This works because the only reasonable override that toolchains might
# supply for these values are to force-disable them.
# But if needs_gomacc_path_arg is set in a Chrome OS build, the toolchain
# wrapper will have picked up gomacc via cmd-line arg. So need to prepend
# gomacc in that case.
goma_path = "$goma_dir/gomacc"
if (toolchain_uses_rbe) {
if (defined(toolchain_args.rbe_cc_cfg_file)) {
toolchain_rbe_cc_cfg_file = toolchain_args.rbe_cc_cfg_file
} else {
toolchain_rbe_cc_cfg_file = rbe_cc_cfg_file
}
# C/C++ (clang) rewrapper prefix to use when use_rbe is true.
compiler_prefix = "${rbe_bin_dir}/rewrapper -cfg=${toolchain_rbe_cc_cfg_file} -exec_root=${rbe_exec_root} "
} else if (toolchain_uses_goma &&
(!defined(invoker_toolchain_args.needs_gomacc_path_arg) ||
!invoker_toolchain_args.needs_gomacc_path_arg)) {
compiler_prefix = "${goma_path} "
} else {
compiler_prefix = "${toolchain_cc_wrapper} "
}
if (use_goma_thin_lto && toolchain_uses_goma && use_thin_lto) {
# goma_ld.py uses autoninja in an attempt to set a reasonable
# number of jobs, but this results in too low a value on
# Chrome OS builders. So we pass in an explicit value.
goma_ld =
"$python_path " +
rebase_path("//tools/clang/scripts/goma_ld.py", root_build_dir) +
" --gomacc ${goma_path} --jobs 200 -- "
} else {
goma_ld = ""
not_needed([ "goma_path" ])
}
# Create a distinct variable for "asm", since coverage runs pass a bunch of
# flags to clang/clang++ that are nonsensical on assembler runs.
asm_prefix = compiler_prefix
# A specific toolchain may wish to avoid coverage instrumentation, so we
# allow the global "use_clang_coverage" arg to be overridden.
if (defined(toolchain_args.use_clang_coverage)) {
toolchain_use_clang_coverage = toolchain_args.use_clang_coverage
} else {
toolchain_use_clang_coverage = use_clang_coverage
}
# For a coverage build, we use the wrapper script globally so that it can
# remove coverage cflags from files that should not have them.
if (toolchain_use_clang_coverage) {
# "coverage_instrumentation_input_file" is set in args.gn, but it can be
# overridden by a toolchain config.
if (defined(toolchain_args.coverage_instrumentation_input_file)) {
toolchain_coverage_instrumentation_input_file =
toolchain_args.coverage_instrumentation_input_file
} else {
toolchain_coverage_instrumentation_input_file =
coverage_instrumentation_input_file
}
_coverage_wrapper =
rebase_path("//build/toolchain/clang_code_coverage_wrapper.py",
root_build_dir)
# The wrapper needs to know what OS we target because it uses that to
# select a list of files that should not be instrumented.
_coverage_wrapper = _coverage_wrapper + " --target-os=" + target_os
# We want to instrument everything if there is no input file set.
# If there is a file we need to give it to the wrapper script so it can
# instrument only those files.
if (toolchain_coverage_instrumentation_input_file != "") {
_coverage_wrapper =
_coverage_wrapper + " --files-to-instrument=" +
rebase_path(toolchain_coverage_instrumentation_input_file,
root_build_dir)
}
compiler_prefix = "$python_path ${_coverage_wrapper} " + compiler_prefix
}
cc = compiler_prefix + invoker.cc
cxx = compiler_prefix + invoker.cxx
asm = asm_prefix + invoker.cc
ar = invoker.ar
ld = "$goma_ld${invoker.ld}"
if (defined(invoker.readelf)) {
readelf = invoker.readelf
} else {
readelf = "readelf"
}
if (defined(invoker.nm)) {
nm = invoker.nm
} else {
nm = "nm"
}
if (defined(invoker.dwp)) {
dwp_switch = " --dwp=\"${invoker.dwp}\""
} else {
dwp_switch = ""
}
if (defined(invoker.shlib_extension)) {
default_shlib_extension = invoker.shlib_extension
} else {
default_shlib_extension = shlib_extension
}
if (defined(invoker.default_shlib_subdir)) {
default_shlib_subdir = invoker.default_shlib_subdir
} else {
default_shlib_subdir = ""
}
if (defined(invoker.executable_extension)) {
default_executable_extension = invoker.executable_extension
} else {
default_executable_extension = ""
}
# Bring these into our scope for string interpolation with default values.
if (defined(invoker.extra_cflags) && invoker.extra_cflags != "") {
extra_cflags = " " + invoker.extra_cflags
} else {
extra_cflags = ""
}
if (defined(invoker.extra_cppflags) && invoker.extra_cppflags != "") {
extra_cppflags = " " + invoker.extra_cppflags
} else {
extra_cppflags = ""
}
if (defined(invoker.extra_cxxflags) && invoker.extra_cxxflags != "") {
extra_cxxflags = " " + invoker.extra_cxxflags
} else {
extra_cxxflags = ""
}
if (defined(invoker.extra_asmflags) && invoker.extra_asmflags != "") {
extra_asmflags = " " + invoker.extra_asmflags
} else {
extra_asmflags = ""
}
if (defined(invoker.extra_ldflags) && invoker.extra_ldflags != "") {
extra_ldflags = " " + invoker.extra_ldflags
} else {
extra_ldflags = ""
}
enable_linker_map = defined(invoker.enable_linker_map) &&
invoker.enable_linker_map && generate_linker_map
# These library switches can apply to all tools below.
lib_switch = "-l"
lib_dir_switch = "-L"
# Object files go in this directory.
object_subdir = "{{target_out_dir}}/{{label_name}}"
tool("cc") {
depfile = "{{output}}.d"
precompiled_header_type = "gcc"
command = "$cc -MMD -MF $depfile ${rebuild_string}{{defines}} {{include_dirs}} {{cflags}} {{cflags_c}}${extra_cppflags}${extra_cflags} -c {{source}} -o {{output}}"
depsformat = "gcc"
description = "CC {{output}}"
outputs = [ "$object_subdir/{{source_name_part}}.o" ]
}
tool("cxx") {
depfile = "{{output}}.d"
precompiled_header_type = "gcc"
command = "$cxx -MMD -MF $depfile ${rebuild_string}{{defines}} {{include_dirs}} {{cflags}} {{cflags_cc}}${extra_cppflags}${extra_cxxflags} -c {{source}} -o {{output}}"
depsformat = "gcc"
description = "CXX {{output}}"
outputs = [ "$object_subdir/{{source_name_part}}.o" ]
}
tool("asm") {
# For GCC we can just use the C compiler to compile assembly.
depfile = "{{output}}.d"
command = "$asm -MMD -MF $depfile ${rebuild_string}{{defines}} {{include_dirs}} {{asmflags}}${extra_asmflags} -c {{source}} -o {{output}}"
depsformat = "gcc"
description = "ASM {{output}}"
outputs = [ "$object_subdir/{{source_name_part}}.o" ]
}
tool("alink") {
if (current_os == "aix") {
# AIX does not support either -D (deterministic output) or response
# files.
command = "$ar -X64 {{arflags}} -r -c -s {{output}} {{inputs}}"
} else {
rspfile = "{{output}}.rsp"
rspfile_content = "{{inputs}}"
command = "\"$ar\" {{arflags}} -r -c -s -D {{output}} @\"$rspfile\""
}
# Remove the output file first so that ar doesn't try to modify the
# existing file.
if (host_os == "win") {
tool_wrapper_path =
rebase_path("//build/toolchain/win/tool_wrapper.py", root_build_dir)
command = "cmd /c $python_path $tool_wrapper_path delete-file {{output}} && $command"
} else {
command = "rm -f {{output}} && $command"
}
# Almost all targets build with //build/config/compiler:thin_archive which
# adds -T to arflags.
description = "AR {{output}}"
outputs = [ "{{output_dir}}/{{target_output_name}}{{output_extension}}" ]
# Shared libraries go in the target out directory by default so we can
# generate different targets with the same name and not have them collide.
default_output_dir = "{{target_out_dir}}"
default_output_extension = ".a"
output_prefix = "lib"
}
tool("solink") {
soname = "{{target_output_name}}{{output_extension}}" # e.g. "libfoo.so".
sofile = "{{output_dir}}/$soname" # Possibly including toolchain dir.
rspfile = sofile + ".rsp"
pool = "//build/toolchain:link_pool($default_toolchain)"
if (defined(invoker.strip)) {
unstripped_sofile = "{{root_out_dir}}/lib.unstripped/$soname"
} else {
unstripped_sofile = sofile
}
# These variables are not built into GN but are helpers that
# implement (1) linking to produce a .so, (2) extracting the symbols
# from that file (3) if the extracted list differs from the existing
# .TOC file, overwrite it, otherwise, don't change it.
tocfile = sofile + ".TOC"
link_command = "$ld -shared -Wl,-soname=\"$soname\" {{ldflags}}${extra_ldflags} -o \"$unstripped_sofile\" @\"$rspfile\""
# Generate a map file to be used for binary size analysis.
# Map file adds ~10% to the link time on a z620.
# With target_os="android", libchrome.so.map.gz is ~20MB.
map_switch = ""
if (enable_linker_map) {
map_file = "$unstripped_sofile.map.gz"
map_switch = " --map-file \"$map_file\""
}
assert(defined(readelf), "to solink you must have a readelf")
assert(defined(nm), "to solink you must have an nm")
strip_switch = ""
if (defined(invoker.strip)) {
strip_switch = "--strip=${invoker.strip} "
}
# This needs a Python script to avoid using a complex shell command
# requiring sh control structures, pipelines, and POSIX utilities.
# The host might not have a POSIX shell and utilities (e.g. Windows).
solink_wrapper =
rebase_path("//build/toolchain/gcc_solink_wrapper.py", root_build_dir)
command = "$python_path \"$solink_wrapper\" --readelf=\"$readelf\" --nm=\"$nm\" $strip_switch$dwp_switch --sofile=\"$unstripped_sofile\" --tocfile=\"$tocfile\"$map_switch --output=\"$sofile\" -- $link_command"
if (target_cpu == "mipsel" && is_component_build && is_android) {
rspfile_content = "-Wl,--start-group -Wl,--whole-archive {{inputs}} {{solibs}} -Wl,--no-whole-archive {{libs}} -Wl,--end-group"
} else {
rspfile_content = "-Wl,--whole-archive {{inputs}} {{solibs}} -Wl,--no-whole-archive {{libs}}"
}
description = "SOLINK $sofile"
# Use this for {{output_extension}} expansions unless a target manually
# overrides it (in which case {{output_extension}} will be what the target
# specifies).
default_output_extension = default_shlib_extension
default_output_dir = "{{root_out_dir}}${default_shlib_subdir}"
output_prefix = "lib"
# Since the above commands only updates the .TOC file when it changes, ask
# Ninja to check if the timestamp actually changed to know if downstream
# dependencies should be recompiled.
restat = true
# Tell GN about the output files. It will link to the sofile but use the
# tocfile for dependency management.
outputs = [
sofile,
tocfile,
]
if (sofile != unstripped_sofile) {
outputs += [ unstripped_sofile ]
if (defined(invoker.use_unstripped_as_runtime_outputs) &&
invoker.use_unstripped_as_runtime_outputs) {
runtime_outputs = [ unstripped_sofile ]
}
}
# Clank build will generate DWP files when Fission is used.
# Other builds generate DWP files outside of the gn link targets, if at
# all.
if (defined(invoker.dwp)) {
outputs += [ unstripped_sofile + ".dwp" ]
if (defined(invoker.use_unstripped_as_runtime_outputs) &&
invoker.use_unstripped_as_runtime_outputs) {
runtime_outputs += [ unstripped_sofile + ".dwp" ]
}
}
if (defined(map_file)) {
outputs += [ map_file ]
}
link_output = sofile
depend_output = tocfile
}
tool("solink_module") {
soname = "{{target_output_name}}{{output_extension}}" # e.g. "libfoo.so".
sofile = "{{output_dir}}/$soname"
rspfile = sofile + ".rsp"
pool = "//build/toolchain:link_pool($default_toolchain)"
if (defined(invoker.strip)) {
unstripped_sofile = "{{root_out_dir}}/lib.unstripped/$soname"
} else {
unstripped_sofile = sofile
}
command = "$ld -shared {{ldflags}}${extra_ldflags} -o \"$unstripped_sofile\" -Wl,-soname=\"$soname\" @\"$rspfile\""
if (defined(invoker.strip)) {
strip_command = "${invoker.strip} -o \"$sofile\" \"$unstripped_sofile\""
command += " && " + strip_command
}
rspfile_content = "-Wl,--whole-archive {{inputs}} {{solibs}} -Wl,--no-whole-archive {{libs}}"
description = "SOLINK_MODULE $sofile"
# Use this for {{output_extension}} expansions unless a target manually
# overrides it (in which case {{output_extension}} will be what the target
# specifies).
if (defined(invoker.loadable_module_extension)) {
default_output_extension = invoker.loadable_module_extension
} else {
default_output_extension = default_shlib_extension
}
default_output_dir = "{{root_out_dir}}${default_shlib_subdir}"
output_prefix = "lib"
outputs = [ sofile ]
if (sofile != unstripped_sofile) {
outputs += [ unstripped_sofile ]
if (defined(invoker.use_unstripped_as_runtime_outputs) &&
invoker.use_unstripped_as_runtime_outputs) {
runtime_outputs = [ unstripped_sofile ]
}
}
}
tool("link") {
exename = "{{target_output_name}}{{output_extension}}"
outfile = "{{output_dir}}/$exename"
rspfile = "$outfile.rsp"
unstripped_outfile = outfile
pool = "//build/toolchain:link_pool($default_toolchain)"
# Use this for {{output_extension}} expansions unless a target manually
# overrides it (in which case {{output_extension}} will be what the target
# specifies).
default_output_extension = default_executable_extension
default_output_dir = "{{root_out_dir}}"
if (defined(invoker.strip)) {
unstripped_outfile = "{{root_out_dir}}/exe.unstripped/$exename"
}
start_group_flag = ""
end_group_flag = ""
if (current_os != "aix") {
# the "--start-group .. --end-group" feature isn't available on the aix ld.
start_group_flag = "-Wl,--start-group"
end_group_flag = "-Wl,--end-group "
}
link_command = "$ld {{ldflags}}${extra_ldflags} -o \"$unstripped_outfile\" $start_group_flag @\"$rspfile\" {{solibs}} $end_group_flag {{libs}}"
# Generate a map file to be used for binary size analysis.
# Map file adds ~10% to the link time on a z620.
# With target_os="android", libchrome.so.map.gz is ~20MB.
map_switch = ""
if (enable_linker_map) {
map_file = "$unstripped_outfile.map.gz"
map_switch = " --map-file \"$map_file\""
}
strip_switch = ""
if (defined(invoker.strip)) {
strip_switch = " --strip=\"${invoker.strip}\" --unstripped-file=\"$unstripped_outfile\""
}
link_wrapper =
rebase_path("//build/toolchain/gcc_link_wrapper.py", root_build_dir)
command = "$python_path \"$link_wrapper\" --output=\"$outfile\"$strip_switch$map_switch$dwp_switch -- $link_command"
description = "LINK $outfile"
rspfile_content = "{{inputs}}"
outputs = [ outfile ]
if (outfile != unstripped_outfile) {
outputs += [ unstripped_outfile ]
if (defined(invoker.use_unstripped_as_runtime_outputs) &&
invoker.use_unstripped_as_runtime_outputs) {
runtime_outputs = [ unstripped_outfile ]
}
}
# Clank build will generate DWP files when Fission is used.
# Other builds generate DWP files outside of the gn link targets, if at
# all.
if (defined(invoker.dwp)) {
outputs += [ unstripped_outfile + ".dwp" ]
if (defined(invoker.use_unstripped_as_runtime_outputs) &&
invoker.use_unstripped_as_runtime_outputs) {
runtime_outputs += [ unstripped_outfile + ".dwp" ]
}
}
if (defined(invoker.link_outputs)) {
outputs += invoker.link_outputs
}
if (defined(map_file)) {
outputs += [ map_file ]
}
}
# These two are really entirely generic, but have to be repeated in
# each toolchain because GN doesn't allow a template to be used here.
# See //build/toolchain/toolchain.gni for details.
tool("stamp") {
command = stamp_command
description = stamp_description
}
tool("copy") {
command = copy_command
description = copy_description
}
tool("action") {
pool = "//build/toolchain:action_pool($default_toolchain)"
}
forward_variables_from(invoker, [ "deps" ])
}
}
# This is a shorthand for gcc_toolchain instances based on the Chromium-built
# version of Clang. Only the toolchain_cpu and toolchain_os variables need to
# be specified by the invoker, and optionally toolprefix if it's a
# cross-compile case. Note that for a cross-compile case this toolchain
# requires a config to pass the appropriate -target option, or else it will
# actually just be doing a native compile. The invoker can optionally override
# use_gold too.
template("clang_toolchain") {
if (defined(invoker.toolprefix)) {
toolprefix = invoker.toolprefix
} else {
toolprefix = ""
}
if (is_starboard) {
clang_base_path = invoker.clang_base_path
}
gcc_toolchain(target_name) {
prefix = rebase_path("$clang_base_path/bin", root_build_dir)
cc = "$prefix/clang"
cxx = "$prefix/clang++"
ld = cxx
readelf = "${toolprefix}readelf"
ar = "${prefix}/llvm-ar"
nm = "${prefix}/llvm-nm"
forward_variables_from(invoker,
[
"strip",
"default_shlib_subdir",
"enable_linker_map",
"use_unstripped_as_runtime_outputs",
])
toolchain_args = {
if (defined(invoker.toolchain_args)) {
forward_variables_from(invoker.toolchain_args, "*")
}
is_clang = true
}
}
}