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gn / gn / e375226345b2be2bfc8c4549702ee3e437b5c136 / . / build / config / compiler / BUILD.gn
blob: 83337d52e4b9bcf6295e687efd043380ae6ca625 [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/android/config.gni")
import("//build/config/c++/c++.gni")
import("//build/config/chrome_build.gni")
import("//build/config/chromecast_build.gni")
import("//build/config/clang/clang.gni")
import("//build/config/compiler/compiler.gni")
import("//build/config/coverage/coverage.gni")
import("//build/config/host_byteorder.gni")
import("//build/config/ui.gni")
import("//build/toolchain/cc_wrapper.gni")
import("//build/toolchain/toolchain.gni")
import("//build_overrides/build.gni")
if (current_cpu == "arm" || current_cpu == "arm64") {
import("//build/config/arm.gni")
}
if (current_cpu == "mipsel" || current_cpu == "mips64el" ||
current_cpu == "mips" || current_cpu == "mips64") {
import("//build/config/mips.gni")
}
if (is_mac) {
import("//build/config/mac/symbols.gni")
}
if (is_ios) {
import("//build/config/ios/ios_sdk.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() {
# Default to warnings as errors for default workflow, where we catch
# warnings with known toolchains. Allow overriding this e.g. for Chromium
# builds on Linux that could use a different version of the compiler.
# With GCC, warnings in no-Chromium code are always not treated as errors.
treat_warnings_as_errors = true
# Normally, Android builds are lightly optimized, even for debug builds, to
# keep binary size down. Setting this flag to true disables such optimization
android_full_debug = false
# Whether to use the binary binutils checked into third_party/binutils.
# These are not multi-arch so cannot be used except on x86 and x86-64 (the
# only two architectures that are currently checked in). Turn this off when
# you are using a custom toolchain and need to control -B in cflags.
linux_use_bundled_binutils =
linux_use_bundled_binutils_override && is_linux &&
(current_cpu == "x64" || current_cpu == "x86")
binutils_path = rebase_path("//third_party/binutils/Linux_x64/Release/bin",
root_build_dir)
# Compile in such a way as to make it possible for the profiler to unwind full
# stack frames. Setting this flag has a large effect on the performance of the
# generated code than just setting profiling, but gives the profiler more
# information to analyze.
# Requires profiling to be set to true.
enable_full_stack_frames_for_profiling = false
# When we are going to use gold we need to find it.
# This is initialized below, after use_gold might have been overridden.
gold_path = false
if (is_win) {
# Whether the VS xtree header has been patched to disable warning 4702. If
# it has, then we don't need to disable 4702 (unreachable code warning).
# The patch is preapplied to the internal toolchain and hence all bots.
msvs_xtree_patched = false
}
# Enable fatal linker warnings. Building Chromium with certain versions
# of binutils can cause linker warning.
# See: https://bugs.chromium.org/p/chromium/issues/detail?id=457359
fatal_linker_warnings = true
# Build with C++ RTTI enabled. Chromium builds without RTTI by default,
# but some sanitizers are known to require it, like CFI diagnostics
# and UBsan variants.
use_rtti = use_cfi_diag || is_ubsan_vptr || is_ubsan_security
# AFDO (Automatic Feedback Directed Optimizer) is a form of profile-guided
# optimization that GCC supports. It used by ChromeOS in their official
# builds. To use it, set auto_profile_path to the path to a file containing
# the needed gcov profiling data.
auto_profile_path = ""
# Optimize for coverage guided fuzzing (balance between speed and number of
# branches)
optimize_for_fuzzing = false
# Optimize symbol files for maximizing goma cache hit rate. This is on by
# default only when goma is enabled on Linux because setting this to true may
# make it harder to debug binaries.
# See below reference for detail.
# https://chromium.googlesource.com/chromium/src/+/master/docs/linux_debugging.md#Source-level-debug-with-fdebug-prefix-map
strip_absolute_paths_from_debug_symbols = is_linux && use_goma
# Allow projects that wish to stay on C++11 to override Chromium's default.
use_cxx11 = false
# Strip the debug info of symbols file in lib.unstripped to reduce size.
strip_debug_info = false
# Path to an AFDO profile to use while building with clang, if any. Empty
# implies none.
clang_sample_profile_path = ""
# Some configurations have default sample profiles. If this is true and
# clang_sample_profile_path is empty, we'll fall back to the default.
#
# We currently only have default profiles for Chromium in-tree, so we disable
# this by default for all downstream projects, since these profiles are likely
# nonsensical for said projects.
clang_use_default_sample_profile = build_with_chromium && is_official_build &&
(is_android || is_desktop_linux)
# Turn this on to have the compiler output extra timing information.
compiler_timing = false
# Set to true to pass --no-rosegment to lld. This is a workaround
# for a KI issue in Valgrind,
# https://bugs.kde.org/show_bug.cgi?id=384727
ro_segment_workaround_for_valgrind = false
# Turn this on to use ghash feature of lld for faster debug link on Windows.
# http://blog.llvm.org/2018/01/improving-link-time-on-windows-with.html
use_ghash = false
}
declare_args() {
# C++11 may not be an option if Android test infrastructure is used.
use_cxx11_on_android = use_cxx11
}
declare_args() {
# Set to true to use icf, Identical Code Folding.
#
# icf=all is broken in older golds, see
# https://sourceware.org/bugzilla/show_bug.cgi?id=17704
# See also https://crbug.com/663886
# `linux_use_bundled_binutils` is to avoid breaking Linux distros which may
# still have a buggy gold.
# chromeos binutils has been patched with the fix, so always use icf there.
# The bug only affects x86 and x64, so we can still use ICF when targeting
# other architectures.
#
# lld doesn't have the bug.
use_icf = (is_posix || is_fuchsia) && !using_sanitizer &&
!(is_android && use_order_profiling) &&
(use_lld ||
(use_gold &&
((!is_android && linux_use_bundled_binutils) || is_chromeos ||
!(current_cpu == "x86" || current_cpu == "x64"))))
}
# Apply the default logic for these values if they were not set explicitly.
if (gold_path == false) {
if (use_gold) {
gold_path = rebase_path("//third_party/binutils/Linux_x64/Release/bin",
root_build_dir)
} else {
gold_path = ""
}
}
if (use_debug_fission == "default") {
use_debug_fission = is_debug && !is_android && !is_win &&
(use_gold || use_lld) && cc_wrapper == ""
}
# default_include_dirs ---------------------------------------------------------
#
# This is a separate config so that third_party code (which would not use the
# source root and might have conflicting versions of some headers) can remove
# this and specify their own include paths.
config("default_include_dirs") {
include_dirs = [
"//",
root_gen_dir,
]
}
# compiler ---------------------------------------------------------------------
#
# Base compiler configuration.
#
# See also "runtime_library" below for related stuff and a discussion about
# where stuff should go. Put warning related stuff in the "warnings" config.
config("compiler") {
asmflags = []
cflags = []
cflags_c = []
cflags_cc = []
cflags_objc = []
cflags_objcc = []
ldflags = []
defines = []
configs = []
inputs = []
# System-specific flags. If your compiler flags apply to one of the
# categories here, add it to the associated file to keep this shared config
# smaller.
if (is_win) {
configs += [ "//build/config/win:compiler" ]
} else if (is_android) {
configs += [ "//build/config/android:compiler" ]
} else if (is_linux) {
configs += [ "//build/config/linux:compiler" ]
} else if (is_nacl) {
configs += [ "//build/config/nacl:compiler" ]
} else if (is_mac) {
configs += [ "//build/config/mac:compiler" ]
} else if (is_ios) {
configs += [ "//build/config/ios:compiler" ]
} else if (is_fuchsia) {
configs += [ "//build/config/fuchsia:compiler" ]
} else if (current_os == "aix") {
configs += [ "//build/config/aix:compiler" ]
}
configs += [
# See the definitions below.
":clang_revision",
":compiler_cpu_abi",
":compiler_codegen",
]
# In general, Windows is totally different, but all the other builds share
# some common GCC configuration.
if (!is_win) {
# Common POSIX compiler flags setup.
# --------------------------------
cflags += [ "-fno-strict-aliasing" ] # See http://crbug.com/32204
# Stack protection.
if (is_mac) {
# The strong variant of the stack protector significantly increases
# binary size, so only enable it in debug mode.
if (is_debug) {
cflags += [ "-fstack-protector-strong" ]
} else {
cflags += [ "-fstack-protector" ]
}
} else if ((is_posix && !is_chromeos && !is_nacl) || is_fuchsia) {
# TODO(phajdan.jr): Use -fstack-protector-strong when our gcc supports it.
# See also https://crbug.com/533294
cflags += [ "--param=ssp-buffer-size=4" ]
# The x86 toolchain currently has problems with stack-protector.
if (is_android && current_cpu == "x86") {
cflags += [ "-fno-stack-protector" ]
} else if (current_os != "aix") {
# Not available on aix.
cflags += [ "-fstack-protector" ]
}
}
# Linker warnings.
if (fatal_linker_warnings && !(is_chromeos && current_cpu == "arm") &&
!(is_android && use_order_profiling) && !is_mac && !is_ios &&
current_os != "aix") {
# TODO(jochen): Enable this on chromeos on arm. http://crbug.com/356580
# TODO(lizeb,pasko): Fix link errors when linking with order_profiling=1
# crbug.com/485542
ldflags += [ "-Wl,--fatal-warnings" ]
}
} else {
cflags += [
# Assume UTF-8 by default to avoid code page dependencies.
"/utf-8",
]
if (is_clang) {
# Don't look for includes in %INCLUDE%.
cflags += [ "/X" ]
}
}
# Eliminate build metadata (__DATE__, __TIME__ and __TIMESTAMP__) for
# deterministic build. See https://crbug.com/314403
if (!is_official_build) {
if (is_win && !is_clang) {
cflags += [
"/wd4117", # Trying to define or undefine a predefined macro.
"/D__DATE__=",
"/D__TIME__=",
"/D__TIMESTAMP__=",
]
} else {
cflags += [
"-Wno-builtin-macro-redefined",
"-D__DATE__=",
"-D__TIME__=",
"-D__TIMESTAMP__=",
]
}
}
if (is_clang && is_debug) {
# Allow comparing the address of references and 'this' against 0
# in debug builds. Technically, these can never be null in
# well-defined C/C++ and Clang can optimize such checks away in
# release builds, but they may be used in asserts in debug builds.
cflags_cc += [
"-Wno-undefined-bool-conversion",
"-Wno-tautological-undefined-compare",
]
}
# Non-Mac Posix and Fuchsia compiler flags setup.
# -----------------------------------
if ((is_posix && !(is_mac || is_ios)) || is_fuchsia) {
if (enable_profiling) {
if (!is_debug) {
cflags += [ "-g" ]
if (enable_full_stack_frames_for_profiling) {
cflags += [
"-fno-inline",
"-fno-optimize-sibling-calls",
]
}
}
}
if (is_official_build) {
# Explicitly pass --build-id to ld. Compilers used to always pass this
# implicitly but don't any more (in particular clang when built without
# ENABLE_LINKER_BUILD_ID=ON). The crash infrastructure does need a build
# id, so explicitly enable it in official builds. It's not needed in
# unofficial builds and computing it does slow down the link, so go with
# faster links in unofficial builds.
ldflags += [ "-Wl,--build-id=sha1" ]
}
if (!is_android) {
defines += [
# _FILE_OFFSET_BITS=64 should not be set on Android in order to maintain
# the behavior of the Android NDK from earlier versions.
# See https://android-developers.googleblog.com/2017/09/introducing-android-native-development.html
"_FILE_OFFSET_BITS=64",
"_LARGEFILE_SOURCE",
"_LARGEFILE64_SOURCE",
]
}
if (!is_nacl) {
if (exclude_unwind_tables) {
cflags += [
"-fno-unwind-tables",
"-fno-asynchronous-unwind-tables",
]
defines += [ "NO_UNWIND_TABLES" ]
} else {
cflags += [ "-funwind-tables" ]
}
}
}
# Linux/Android/Fuchsia common flags setup.
# ---------------------------------
if (is_linux || is_android || is_fuchsia) {
if (use_pic) {
cflags += [ "-fPIC" ]
ldflags += [ "-fPIC" ]
}
# Use pipes for communicating between sub-processes. Faster.
cflags += [ "-pipe" ]
ldflags += [
"-Wl,-z,noexecstack",
"-Wl,-z,now",
"-Wl,-z,relro",
]
if (!using_sanitizer) {
ldflags += [
"-Wl,-z,defs",
"-Wl,--as-needed",
]
}
}
# Linux-specific compiler flags setup.
# ------------------------------------
if (is_android && is_clang) {
_rebased_android_toolchain_root =
rebase_path(android_toolchain_root, root_build_dir)
# Let clang find the linker in the NDK.
ldflags += [ "--gcc-toolchain=$_rebased_android_toolchain_root" ]
}
if (((is_posix || is_fuchsia) && use_lld) ||
(target_os == "chromeos" && is_android)) {
# NOTE: Some Chrome OS builds globally disable LLD, but they also build some
# targets against Android toolchains which should use LLD. Therefore we
# explicitly select LLD in these cases.
#
# TODO(https://crbug.com/837095): This should be cleaned up if/when LLD can
# work properly for Chrome OS builds.
ldflags += [ "-fuse-ld=lld" ]
if (current_cpu == "arm64") {
# Reduce the page size from 65536 in order to reduce binary size slightly
# by shrinking the alignment gap between segments. This also causes all
# segments to be mapped adjacently, which breakpad relies on.
ldflags += [ "-Wl,-z,max-page-size=4096" ]
}
} else if (use_gold) {
ldflags += [ "-fuse-ld=gold" ]
if (!is_android) {
# On Android, this isn't needed. gcc in the NDK knows to look next to
# it with -fuse-ld=gold, and clang gets a --gcc-toolchain flag passed
# above.
ldflags += [ "-B$gold_path" ]
if (linux_use_bundled_binutils) {
ldflags += [
# Experimentation found that using four linking threads
# saved ~20% of link time.
# https://groups.google.com/a/chromium.org/group/chromium-dev/browse_thread/thread/281527606915bb36
# Only apply this to the target linker, since the host
# linker might not be gold, but isn't used much anyway.
"-Wl,--threads",
"-Wl,--thread-count=4",
]
}
}
# TODO(thestig): Make this flag work with GN.
#if (!is_official_build && !is_chromeos && !(is_asan || is_lsan || is_tsan || is_msan)) {
# ldflags += [
# "-Wl,--detect-odr-violations",
# ]
#}
} else if (linux_use_bundled_binutils) {
# Gold is the default linker for the bundled binutils so we explicitly
# enable the bfd linker when use_gold is not set.
ldflags += [ "-fuse-ld=bfd" ]
}
if (use_icf) {
ldflags += [ "-Wl,--icf=all" ]
}
if (linux_use_bundled_binutils) {
cflags += [ "-B$binutils_path" ]
}
if (is_linux) {
cflags += [ "-pthread" ]
# Do not use the -pthread ldflag here since it becomes a no-op
# when using -nodefaultlibs, which would cause an unused argument
# error. "-lpthread" is added in //build/config:default_libs.
}
# Clang-specific compiler flags setup.
# ------------------------------------
if (is_clang) {
cflags += [ "-fcolor-diagnostics" ]
# Enable -fmerge-all-constants. This used to be the default in clang
# for over a decade. It makes clang non-conforming, but is fairly safe
# in practice and saves some binary size. We might want to consider
# disabling this (https://bugs.llvm.org/show_bug.cgi?id=18538#c13),
# but for now it looks like our build might rely on it
# (https://crbug.com/829795).
cflags += [ "-fmerge-all-constants" ]
}
if (use_lld) {
# TODO(thakis): Make the driver pass --color-diagnostics to the linker
# if -fcolor-diagnostics is passed to it, and pass -fcolor-diagnostics
# in ldflags instead.
if (is_win) {
# On Windows, we call the linker directly, instead of calling it through
# the driver.
ldflags += [ "--color-diagnostics" ]
} else {
ldflags += [ "-Wl,--color-diagnostics" ]
}
}
if (is_clang && !is_nacl && current_toolchain == host_toolchain &&
target_os != "chromeos") {
cflags += [
# TODO(hans): Remove this once Clang generates better optimized debug info
# by default. https://crbug.com/765793
"-Xclang",
"-mllvm",
"-Xclang",
"-instcombine-lower-dbg-declare=0",
]
}
# Print absolute paths in diagnostics. There is no precedent for doing this
# on Linux/Mac (GCC doesn't support it), but MSVC does this with /FC and
# Windows developers rely on it (crbug.com/636109) so only do this on Windows.
if (msvc_use_absolute_paths && is_clang && is_win) {
cflags += [ "-fdiagnostics-absolute-paths" ]
}
# Makes builds independent of absolute file path.
# clang-cl (used if is_win) doesn't expose this flag.
# Currently disabled for nacl since its toolchain lacks this flag (too old).
# TODO(zforman): Once nacl's toolchain is updated, remove check.
if (is_clang && !is_nacl && !is_win && !is_mac && !is_ios &&
strip_absolute_paths_from_debug_symbols) {
# This is resolved to path like "$HOME/chromium/src/out/Release".
# If debug option is given, clang includes $cwd in debug info.
# In such build, this flag generates reproducible obj files
# even we use build directory like "out/feature_a" and "out/feature_b" if
# we build same files with same compile flag other than this.
# Other paths are already givne in relative, no need to normalize it by
# using -fdebug-prefix-map.
absolute_path = rebase_path(root_out_dir)
cflags += [ "-fdebug-prefix-map=$absolute_path=." ]
}
# Tells the compiler not to use absolute paths when passing the default
# paths to the tools it invokes. We don't want this because we don't
# really need it and it can mess up the goma cache entries. It would
# be nice if it was on by default in clang, but it isn't.
#
# TODO(thakis): Figure out if this should be the default, and expose in
# clang-cl if not.
if (is_clang && !is_win && !is_nacl) {
cflags += [ "-no-canonical-prefixes" ]
}
# C11/C++11 compiler flags setup.
# ---------------------------
if (is_linux || is_android || (is_nacl && is_clang) || current_os == "aix") {
if (target_os == "android") {
cxx11_override = use_cxx11_on_android
} else {
cxx11_override = use_cxx11
}
# gnu11/gnu++11 instead of c11/c++11 is needed because some code uses typeof()
# (a GNU extension).
# TODO(thakis): Eventually switch this to c++11 instead,
# http://crbug.com/427584
cflags_c += [ "-std=gnu11" ]
if (cxx11_override) {
# Override Chromium's default for projects that wish to stay on C++11.
cflags_cc += [ "-std=gnu++11" ]
} else {
cflags_cc += [ "-std=gnu++14" ]
}
} else if (!is_win && !is_nacl) {
if (target_os == "android") {
cxx11_override = use_cxx11_on_android
} else {
cxx11_override = use_cxx11
}
# TODO(mcgrathr) - the NaCl GCC toolchain doesn't support either gnu11/gnu++11
# or c11/c++11; we technically don't need this toolchain any more, but there
# are still a few buildbots using it, so until those are turned off
# we need the !is_nacl clause and the (is_nacl && is_clang) clause, above.
cflags_c += [ "-std=c11" ]
if (cxx11_override) {
cflags_cc += [ "-std=c++11" ]
} else {
cflags_cc += [ "-std=c++14" ]
}
}
if (is_mac) {
# The system libc++ on Mac doesn't have aligned allocation in C++17.
defines += [ "_LIBCPP_HAS_NO_ALIGNED_ALLOCATION" ]
cflags_cc += [ "-stdlib=libc++" ]
ldflags += [ "-stdlib=libc++" ]
}
# Add flags for link-time optimization. These flags enable
# optimizations/transformations that require whole-program visibility at link
# time, so they need to be applied to all translation units, and we may end up
# with miscompiles if only part of the program is compiled with LTO flags. For
# that reason, we cannot allow targets to enable or disable these flags, for
# example by disabling the optimize configuration.
# TODO(pcc): Make this conditional on is_official_build rather than on gn
# flags for specific features.
if (!is_debug && use_thin_lto && current_toolchain == default_toolchain) {
assert(use_lld || target_os == "chromeos",
"gold plugin only supported with ChromeOS")
cflags += [ "-flto=thin" ]
# Limit the size of the ThinLTO cache to the lesser of 10% of available disk
# space, 10GB and 100000 files.
if (use_lld) {
cache_policy =
"cache_size=10%:cache_size_bytes=10g:cache_size_files=100000"
}
if (is_win) {
# This is a straight translation of the non-Windows flags below.
ldflags += [
"/opt:lldlto=0",
"/opt:lldltojobs=8",
"/lldltocache:" +
rebase_path("$root_out_dir/thinlto-cache", root_build_dir),
"/lldltocachepolicy:$cache_policy",
]
} else {
ldflags += [ "-flto=thin" ]
# Limit the parallelism to avoid too aggressive competition between
# linker jobs. This is still suboptimal to a potential dynamic
# resource allocation scheme, but should be good enough.
if (use_lld) {
ldflags += [
"-Wl,--thinlto-jobs=8",
"-Wl,--thinlto-cache-dir=" +
rebase_path("$root_out_dir/thinlto-cache", root_build_dir),
"-Wl,--thinlto-cache-policy,$cache_policy",
]
} else {
ldflags += [ "-Wl,-plugin-opt,jobs=8" ]
not_needed([ "cache_policy" ])
}
}
# Disable optimization for now because they increase binary size by too
# much.
if (use_lld && (is_android || (is_linux && !is_chromeos))) {
ldflags += [ "-Wl,--lto-O0" ]
}
cflags += [ "-fwhole-program-vtables" ]
if (!is_win) {
ldflags += [ "-fwhole-program-vtables" ]
}
# Work-around for http://openradar.appspot.com/20356002
if (is_mac) {
ldflags += [ "-Wl,-all_load" ]
}
# This flag causes LTO to create an .ARM.attributes section with the correct
# architecture. This is necessary because LLD will refuse to link a program
# unless the architecture revision in .ARM.attributes is sufficiently new.
# TODO(pcc): The contents of .ARM.attributes should be based on the
# -march flag passed at compile time (see llvm.org/pr36291).
if (current_cpu == "arm") {
ldflags += [ "-march=$arm_arch" ]
}
}
if (compiler_timing) {
if (is_clang) {
if (is_win) {
cflags += [ "-Xclang" ]
}
cflags += [ "-ftime-report" ]
} else if (is_win) {
cflags += [
# "Documented" here:
# http://aras-p.info/blog/2017/10/23/Best-unknown-MSVC-flag-d2cgsummary/
"/d2cgsummary",
]
}
}
# Pass flag to LLD to work around issue in Valgrind related to
# location of debug symbols.
if (use_lld && ro_segment_workaround_for_valgrind) {
ldflags += [ "-Wl,--no-rosegment" ]
}
# Pass the same C/C++ flags to the objective C/C++ compiler.
cflags_objc += cflags_c
cflags_objcc += cflags_cc
# Assign any flags set for the C compiler to asmflags so that they are sent
# to the assembler. The Windows assembler takes different types of flags
# so only do so for posix platforms.
if (is_posix || is_fuchsia) {
asmflags += cflags
asmflags += cflags_c
}
}
# This provides the basic options to select the target CPU and ABI.
# It is factored out of "compiler" so that special cases can use this
# without using everything that "compiler" brings in. Options that
# tweak code generation for a particular CPU do not belong here!
# See "compiler_codegen", below.
config("compiler_cpu_abi") {
cflags = []
ldflags = []
defines = []
if ((is_posix && !(is_mac || is_ios)) || is_fuchsia) {
# CPU architecture. We may or may not be doing a cross compile now, so for
# simplicity we always explicitly set the architecture.
if (current_cpu == "x64") {
cflags += [
"-m64",
"-march=x86-64",
]
ldflags += [ "-m64" ]
} else if (current_cpu == "x86") {
cflags += [ "-m32" ]
ldflags += [ "-m32" ]
if (!is_nacl) {
cflags += [
"-msse2",
"-mfpmath=sse",
"-mmmx",
]
}
} else if (current_cpu == "arm") {
if (is_clang && !is_android && !is_nacl) {
cflags += [ "--target=arm-linux-gnueabihf" ]
ldflags += [ "--target=arm-linux-gnueabihf" ]
}
if (!is_nacl) {
cflags += [
"-march=$arm_arch",
"-mfloat-abi=$arm_float_abi",
]
}
if (arm_tune != "") {
cflags += [ "-mtune=$arm_tune" ]
}
} else if (current_cpu == "arm64") {
if (is_clang && !is_android && !is_nacl && !is_fuchsia) {
cflags += [ "--target=aarch64-linux-gnu" ]
ldflags += [ "--target=aarch64-linux-gnu" ]
}
} else if (current_cpu == "mipsel" && !is_nacl) {
if (custom_toolchain == "") {
if (is_clang) {
if (is_android) {
cflags += [ "--target=mipsel-linux-android" ]
ldflags += [ "--target=mipsel-linux-android" ]
} else {
cflags += [ "--target=mipsel-linux-gnu" ]
ldflags += [ "--target=mipsel-linux-gnu" ]
}
} else {
cflags += [ "-EL" ]
ldflags += [ "-EL" ]
}
}
if (mips_arch_variant == "r6") {
cflags += [ "-mno-odd-spreg" ]
ldflags += [ "-mips32r6" ]
if (is_clang) {
cflags += [
"-march=mipsel",
"-mcpu=mips32r6",
]
} else {
cflags += [
"-mips32r6",
"-Wa,-mips32r6",
]
if (is_android) {
ldflags += [ "-Wl,-melf32ltsmip" ]
}
}
if (mips_use_msa == true) {
cflags += [
"-mmsa",
"-mfp64",
]
}
} else if (mips_arch_variant == "r2") {
ldflags += [ "-mips32r2" ]
if (is_clang) {
cflags += [
"-march=mipsel",
"-mcpu=mips32r2",
]
} else {
cflags += [
"-mips32r2",
"-Wa,-mips32r2",
]
if (mips_float_abi == "hard" && mips_fpu_mode != "") {
cflags += [ "-m$mips_fpu_mode" ]
}
}
} else if (mips_arch_variant == "r1") {
ldflags += [ "-mips32" ]
if (is_clang) {
cflags += [
"-march=mipsel",
"-mcpu=mips32",
]
} else {
cflags += [
"-mips32",
"-Wa,-mips32",
]
}
} else if (mips_arch_variant == "loongson3") {
defines += [ "_MIPS_ARCH_LOONGSON" ]
cflags += [
"-march=loongson3a",
"-mno-branch-likely",
"-Wa,-march=loongson3a",
]
}
if (mips_dsp_rev == 1) {
cflags += [ "-mdsp" ]
} else if (mips_dsp_rev == 2) {
cflags += [ "-mdspr2" ]
}
cflags += [ "-m${mips_float_abi}-float" ]
} else if (current_cpu == "mips" && !is_nacl) {
if (custom_toolchain == "") {
if (is_clang) {
cflags += [ "--target=mips-linux-gnu" ]
ldflags += [ "--target=mips-linux-gnu" ]
} else {
cflags += [ "-EB" ]
ldflags += [ "-EB" ]
}
}
if (mips_arch_variant == "r6") {
cflags += [
"-mips32r6",
"-Wa,-mips32r6",
]
if (mips_use_msa == true) {
cflags += [
"-mmsa",
"-mfp64",
]
}
} else if (mips_arch_variant == "r2") {
cflags += [
"-mips32r2",
"-Wa,-mips32r2",
]
if (mips_float_abi == "hard" && mips_fpu_mode != "") {
cflags += [ "-m$mips_fpu_mode" ]
}
} else if (mips_arch_variant == "r1") {
cflags += [
"-mips32",
"-Wa,-mips32",
]
}
if (mips_dsp_rev == 1) {
cflags += [ "-mdsp" ]
} else if (mips_dsp_rev == 2) {
cflags += [ "-mdspr2" ]
}
cflags += [ "-m${mips_float_abi}-float" ]
} else if (current_cpu == "mips64el") {
if (custom_toolchain == "") {
if (is_clang) {
if (is_android) {
cflags += [ "--target=mips64el-linux-android" ]
ldflags += [ "--target=mips64el-linux-android" ]
} else {
cflags += [ "--target=mips64el-linux-gnuabi64" ]
ldflags += [ "--target=mips64el-linux-gnuabi64" ]
}
} else {
cflags += [
"-EL",
"-mabi=64",
]
ldflags += [
"-EL",
"-mabi=64",
]
}
}
if (mips_arch_variant == "r6") {
if (is_clang) {
cflags += [
"-march=mips64el",
"-mcpu=mips64r6",
]
} else {
cflags += [
"-mips64r6",
"-Wa,-mips64r6",
]
ldflags += [ "-mips64r6" ]
}
if (mips_use_msa == true) {
cflags += [
"-mmsa",
"-mfp64",
]
}
} else if (mips_arch_variant == "r2") {
ldflags += [ "-mips64r2" ]
if (is_clang) {
cflags += [
"-march=mips64el",
"-mcpu=mips64r2",
]
} else {
cflags += [
"-mips64r2",
"-Wa,-mips64r2",
]
}
} else if (mips_arch_variant == "loongson3") {
defines += [ "_MIPS_ARCH_LOONGSON" ]
cflags += [
"-march=loongson3a",
"-mno-branch-likely",
"-Wa,-march=loongson3a",
]
}
} else if (current_cpu == "mips64") {
if (custom_toolchain == "") {
if (is_clang) {
cflags += [ "--target=mips64-linux-gnuabi64" ]
ldflags += [ "--target=mips64-linux-gnuabi64" ]
} else {
cflags += [
"-EB",
"-mabi=64",
]
ldflags += [
"-EB",
"-mabi=64",
]
}
}
if (mips_arch_variant == "r6") {
cflags += [
"-mips64r6",
"-Wa,-mips64r6",
]
ldflags += [ "-mips64r6" ]
if (mips_use_msa == true) {
cflags += [
"-mmsa",
"-mfp64",
]
}
} else if (mips_arch_variant == "r2") {
cflags += [
"-mips64r2",
"-Wa,-mips64r2",
]
ldflags += [ "-mips64r2" ]
}
} else if (current_cpu == "pnacl" && is_nacl_nonsfi) {
if (target_cpu == "x86" || target_cpu == "x64") {
cflags += [
"-arch",
"x86-32-nonsfi",
"--pnacl-bias=x86-32-nonsfi",
"--target=i686-unknown-nacl",
]
ldflags += [
"-arch",
"x86-32-nonsfi",
"--target=i686-unknown-nacl",
]
} else if (target_cpu == "arm") {
cflags += [
"-arch",
"arm-nonsfi",
"-mfloat-abi=hard",
"--pnacl-bias=arm-nonsfi",
"--target=armv7-unknown-nacl-gnueabihf",
]
ldflags += [
"-arch",
"arm-nonsfi",
"--target=armv7-unknown-nacl-gnueabihf",
]
}
} else if (current_cpu == "ppc64") {
if (v8_current_cpu == "ppc") {
cflags += [ "-m32" ]
ldflags += [ "-m32" ]
} else if (v8_current_cpu == "ppc64") {
if (current_os == "aix") {
cflags += [ "-maix64" ]
ldflags += [ "-maix64" ]
} else {
cflags += [ "-m64" ]
ldflags += [ "-m64" ]
}
}
} else if (current_cpu == "s390x") {
if (v8_current_cpu == "s390" && host_byteorder == "little") {
cflags += [ "-m32" ]
ldflags += [ "-m32" ]
} else if (v8_current_cpu == "s390") {
cflags += [ "-m31" ]
ldflags += [ "-m31" ]
} else if (v8_current_cpu == "s390x") {
cflags += [ "-m64" ]
ldflags += [ "-m64" ]
}
}
}
asmflags = cflags
}
# This provides options to tweak code generation that are necessary
# for particular Chromium code or for working around particular
# compiler bugs (or the combination of the two).
config("compiler_codegen") {
configs = []
cflags = []
if (is_nacl) {
configs += [ "//build/config/nacl:compiler_codegen" ]
} else if (is_posix && !is_mac && !is_ios) {
if (current_cpu == "x86") {
if (is_clang) {
cflags += [
# Else building libyuv gives clang's register allocator issues,
# see llvm.org/PR15798 / crbug.com/233709
"-momit-leaf-frame-pointer",
]
}
} else if (current_cpu == "arm") {
if (is_android && !is_clang) {
# Clang doesn't support these flags.
cflags += [
# The tree-sra optimization (scalar replacement for
# aggregates enabling subsequent optimizations) leads to
# invalid code generation when using the Android NDK's
# compiler (r5-r7). This can be verified using
# webkit_unit_tests' WTF.Checked_int8_t test.
"-fno-tree-sra",
# The following option is disabled to improve binary
# size and performance in gcc 4.9.
"-fno-caller-saves",
]
}
}
}
asmflags = cflags
}
# This is separate from :compiler_codegen (and not even a sub-config there)
# so that some targets can remove it from the list with:
# configs -= [ "//build/config/compiler:clang_stackrealign" ]
# See https://crbug.com/556393 for details of where it must be avoided.
config("clang_stackrealign") {
if (is_clang && current_cpu == "x86" && is_linux) {
cflags = [
# Align the stack on 16-byte boundaries, http://crbug.com/418554.
"-mstack-alignment=16",
"-mstackrealign",
]
}
}
config("clang_revision") {
if (is_clang && clang_base_path == default_clang_base_path) {
update_args = [
"--print-revision",
"--verify-version=$clang_version",
]
if (llvm_force_head_revision) {
update_args += [ "--llvm-force-head-revision" ]
}
clang_revision = exec_script("//tools/clang/scripts/update.py",
update_args,
"trim string")
# This is here so that all files get recompiled after a clang roll and
# when turning clang on or off. (defines are passed via the command line,
# and build system rebuild things when their commandline changes). Nothing
# should ever read this define.
defines = [ "CR_CLANG_REVISION=\"$clang_revision\"" ]
}
}
config("compiler_arm_fpu") {
if (current_cpu == "arm" && !is_ios && !is_nacl) {
cflags = [ "-mfpu=$arm_fpu" ]
asmflags = cflags
}
}
config("compiler_arm_thumb") {
if (current_cpu == "arm" && arm_use_thumb && is_posix &&
!(is_mac || is_ios || is_nacl)) {
cflags = [ "-mthumb" ]
if (is_android && !is_clang) {
# Clang doesn't support this option.
cflags += [ "-mthumb-interwork" ]
}
}
}
config("compiler_arm") {
if (current_cpu == "arm" && is_chromeos) {
# arm is normally the default mode for clang, but on chromeos a wrapper
# is used to pass -mthumb, and therefor change the default.
cflags = [ "-marm" ]
}
}
# runtime_library -------------------------------------------------------------
#
# Sets the runtime library and associated options.
#
# How do you determine what should go in here vs. "compiler" above? Consider if
# a target might choose to use a different runtime library (ignore for a moment
# if this is possible or reasonable on your system). If such a target would want
# to change or remove your option, put it in the runtime_library config. If a
# target wants the option regardless, put it in the compiler config.
config("runtime_library") {
defines = []
configs = []
# TODO(crbug.com/830987): Come up with a better name for is POSIX + Fuchsia
# configuration.
#
# The order of this config is important: it must appear before
# android:runtime_library. This is to ensure libc++ appears before
# libandroid_support in the -isystem include order. Otherwise, there will be
# build errors related to symbols declared in math.h.
if (is_posix || is_fuchsia) {
configs += [ "//build/config/posix:runtime_library" ]
}
# System-specific flags. If your compiler flags apply to one of the
# categories here, add it to the associated file to keep this shared config
# smaller.
if (is_win) {
configs += [ "//build/config/win:runtime_library" ]
} else if (is_linux) {
configs += [ "//build/config/linux:runtime_library" ]
} else if (is_ios) {
configs += [ "//build/config/ios:runtime_library" ]
} else if (is_mac) {
configs += [ "//build/config/mac:runtime_library" ]
} else if (is_android) {
configs += [ "//build/config/android:runtime_library" ]
}
if (is_component_build) {
defines += [ "COMPONENT_BUILD" ]
}
}
# default_warnings ------------------------------------------------------------
#
# Collects all warning flags that are used by default. This is used as a
# subconfig of both chromium_code and no_chromium_code. This way these
# flags are guaranteed to appear on the compile command line after -Wall.
config("default_warnings") {
cflags = []
cflags_cc = []
ldflags = []
if (is_win) {
if (treat_warnings_as_errors) {
cflags += [ "/WX" ]
}
if (fatal_linker_warnings) {
ldflags += [ "/WX" ]
}
cflags += [
# Warnings permanently disabled:
# C4091: 'typedef ': ignored on left of 'X' when no variable is
# declared.
# This happens in a number of Windows headers. Dumb.
"/wd4091",
# C4127: conditional expression is constant
# This warning can in theory catch dead code and other problems, but
# triggers in far too many desirable cases where the conditional
# expression is either set by macros or corresponds some legitimate
# compile-time constant expression (due to constant template args,
# conditionals comparing the sizes of different types, etc.). Some of
# these can be worked around, but it's not worth it.
"/wd4127",
# C4251: 'identifier' : class 'type' needs to have dll-interface to be
# used by clients of class 'type2'
# This is necessary for the shared library build.
"/wd4251",
# C4275: non dll-interface class used as base for dll-interface class
# This points out a potential (but rare) problem with referencing static
# fields of a non-exported base, through the base's non-exported inline
# functions, or directly. The warning is subtle enough that people just
# suppressed it when they saw it, so it's not worth it.
"/wd4275",
# C4312 is a VS 2015 64-bit warning for integer to larger pointer.
# TODO(brucedawson): fix warnings, crbug.com/554200
"/wd4312",
# C4324 warns when padding is added to fulfill alignas requirements,
# but can trigger in benign cases that are difficult to individually
# suppress.
"/wd4324",
# C4351: new behavior: elements of array 'array' will be default
# initialized
# This is a silly "warning" that basically just alerts you that the
# compiler is going to actually follow the language spec like it's
# supposed to, instead of not following it like old buggy versions did.
# There's absolutely no reason to turn this on.
"/wd4351",
# C4355: 'this': used in base member initializer list
# It's commonly useful to pass |this| to objects in a class' initializer
# list. While this warning can catch real bugs, most of the time the
# constructors in question don't attempt to call methods on the passed-in
# pointer (until later), and annotating every legit usage of this is
# simply more hassle than the warning is worth.
"/wd4355",
# C4503: 'identifier': decorated name length exceeded, name was
# truncated
# This only means that some long error messages might have truncated
# identifiers in the presence of lots of templates. It has no effect on
# program correctness and there's no real reason to waste time trying to
# prevent it.
"/wd4503",
# Warning C4589 says: "Constructor of abstract class ignores
# initializer for virtual base class." Disable this warning because it
# is flaky in VS 2015 RTM. It triggers on compiler generated
# copy-constructors in some cases.
"/wd4589",
# C4611: interaction between 'function' and C++ object destruction is
# non-portable
# This warning is unavoidable when using e.g. setjmp/longjmp. MSDN
# suggests using exceptions instead of setjmp/longjmp for C++, but
# Chromium code compiles without exception support. We therefore have to
# use setjmp/longjmp for e.g. JPEG decode error handling, which means we
# have to turn off this warning (and be careful about how object
# destruction happens in such cases).
"/wd4611",
# Warnings to evaluate and possibly fix/reenable later:
"/wd4100", # Unreferenced formal function parameter.
"/wd4121", # Alignment of a member was sensitive to packing.
"/wd4244", # Conversion: possible loss of data.
"/wd4505", # Unreferenced local function has been removed.
"/wd4510", # Default constructor could not be generated.
"/wd4512", # Assignment operator could not be generated.
"/wd4610", # Class can never be instantiated, constructor required.
"/wd4838", # Narrowing conversion. Doesn't seem to be very useful.
"/wd4995", # 'X': name was marked as #pragma deprecated
"/wd4996", # Deprecated function warning.
# These are variable shadowing warnings that are new in VS2015. We
# should work through these at some point -- they may be removed from
# the RTM release in the /W4 set.
"/wd4456",
"/wd4457",
"/wd4458",
"/wd4459",
]
cflags_cc += [
# Allow "noexcept" annotations even though we compile with exceptions
# disabled.
"/wd4577",
]
if (current_cpu == "x86") {
cflags += [
# VC++ 2015 changes 32-bit size_t truncation warnings from 4244 to
# 4267. Example: short TruncTest(size_t x) { return x; }
# Since we disable 4244 we need to disable 4267 during migration.
# TODO(jschuh): crbug.com/167187 fix size_t to int truncations.
"/wd4267",
]
}
# VS xtree header file needs to be patched or 4702 (unreachable code
# warning) is reported if _HAS_EXCEPTIONS=0. Disable the warning if xtree is
# not patched.
if (!msvs_xtree_patched &&
exec_script("../../win_is_xtree_patched.py", [], "value") == 0) {
cflags += [ "/wd4702" ] # Unreachable code.
}
} else {
if ((is_mac || is_ios) && !is_nacl) {
# When compiling Objective-C, warns if a method is used whose
# availability is newer than the deployment target.
cflags += [ "-Wunguarded-availability" ]
}
if (is_ios) {
# When compiling Objective-C, warns if a selector named via @selector has
# not been defined in any visible interface.
cflags += [ "-Wundeclared-selector" ]
}
# Suppress warnings about ABI changes on ARM (Clang doesn't give this
# warning).
if (current_cpu == "arm" && !is_clang) {
cflags += [ "-Wno-psabi" ]
}
if (!is_clang) {
cflags_cc += [
# See comment for -Wno-c++11-narrowing.
"-Wno-narrowing",
]
# -Wunused-local-typedefs is broken in gcc,
# https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63872
cflags += [ "-Wno-unused-local-typedefs" ]
# Don't warn about "maybe" uninitialized. Clang doesn't include this
# in -Wall but gcc does, and it gives false positives.
cflags += [ "-Wno-maybe-uninitialized" ]
cflags += [ "-Wno-deprecated-declarations" ]
# GCC assumes 'this' is never nullptr and optimizes away code
# like "if (this == nullptr) ...": [1]. However, some Chromium
# code relies on these types of null pointer checks [2], so
# disable this optimization.
# [1] https://gcc.gnu.org/gcc-6/porting_to.html#this-cannot-be-null
# [2] https://crbug.com/784492#c13
cflags += [ "-fno-delete-null-pointer-checks" ]
# -Wcomment gives too many false positives in the case a
# backslash ended comment line is followed by a new line of
# comments
# https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61638
cflags += [ "-Wno-comments" ]
}
}
# Common Clang and GCC warning setup.
if (!is_win || is_clang) {
cflags += [
# Disables.
"-Wno-missing-field-initializers", # "struct foo f = {0};"
"-Wno-unused-parameter", # Unused function parameters.
]
}
if (is_clang) {
cflags += [
# TODO(thakis): Consider -Wloop-analysis (turns on
# -Wrange-loop-analysis too).
# This warns on using ints as initializers for floats in
# initializer lists (e.g. |int a = f(); CGSize s = { a, a };|),
# which happens in several places in chrome code. Not sure if
# this is worth fixing.
"-Wno-c++11-narrowing",
# Warns on switches on enums that cover all enum values but
# also contain a default: branch. Chrome is full of that.
"-Wno-covered-switch-default",
# TODO(thakis): This used to be implied by -Wno-unused-function,
# which we no longer use. Check if it makes sense to remove
# this as well. http://crbug.com/316352
"-Wno-unneeded-internal-declaration",
]
# use_xcode_clang only refers to the iOS toolchain, host binaries use
# chromium's clang always.
if (!is_nacl && (!use_xcode_clang || current_toolchain == host_toolchain)) {
# Flags NaCl (Clang 3.7) and Xcode 7.3 (Clang clang-703.0.31) do not
# recognize.
cflags += [
# TODO(thakis): https://crbug.com/604888
"-Wno-undefined-var-template",
# TODO(thakis): https://crbug.com/617318
"-Wno-nonportable-include-path",
# TODO(hans): https://crbug.com/637306
"-Wno-address-of-packed-member",
# TODO(hans): https://crbug.com/681136
"-Wno-unused-lambda-capture",
# TODO(thakis ): https://crbug.com/683349
"-Wno-user-defined-warnings",
# TODO(thakis): https://crbug.com/753973
"-Wno-enum-compare-switch",
# TODO(hans): https://crbug.com/766891
"-Wno-null-pointer-arithmetic",
# Ignore warnings about MSVC optimization pragmas.
# TODO(thakis): Only for no_chromium_code? http://crbug.com/505314
"-Wno-ignored-pragma-optimize",
]
} else if (use_xcode_clang) {
cflags += [
# TODO(thakis): https://crbug.com/604888
"-Wno-undefined-var-template",
# TODO(hans): https://crbug.com/637306
"-Wno-address-of-packed-member",
]
}
}
}
# chromium_code ---------------------------------------------------------------
#
# Toggles between higher and lower warnings for code that is (or isn't)
# part of Chromium.
config("chromium_code") {
if (is_win) {
cflags = [ "/W4" ] # Warning level 4.
} else {
cflags = [ "-Wall" ]
if (treat_warnings_as_errors) {
cflags += [ "-Werror" ]
# The compiler driver can sometimes (rarely) emit warnings before calling
# the actual linker. Make sure these warnings are treated as errors as
# well.
ldflags = [ "-Werror" ]
}
if (is_clang) {
# Enable extra warnings for chromium_code when we control the compiler.
cflags += [ "-Wextra" ]
}
# In Chromium code, we define __STDC_foo_MACROS in order to get the
# C99 macros on Mac and Linux.
defines = [
"__STDC_CONSTANT_MACROS",
"__STDC_FORMAT_MACROS",
]
if (!is_debug && !using_sanitizer &&
(!is_linux || !is_clang || is_official_build) &&
current_cpu != "s390x" && current_cpu != "s390" &&
current_cpu != "ppc64" && current_cpu != "ppc64" &&
current_cpu != "mips" && current_cpu != "mips64") {
# _FORTIFY_SOURCE isn't really supported by Clang now, see
# http://llvm.org/bugs/show_bug.cgi?id=16821.
# It seems to work fine with Ubuntu 12 headers though, so use it in
# official builds.
#
# Non-chromium code is not guaranteed to compile cleanly with
# _FORTIFY_SOURCE. Also, fortified build may fail when optimizations are
# disabled, so only do that for Release build.
defines += [ "_FORTIFY_SOURCE=2" ]
}
if (is_mac || is_ios) {
cflags_objc = [ "-Wobjc-missing-property-synthesis" ]
cflags_objcc = [ "-Wobjc-missing-property-synthesis" ]
}
}
if (is_clang) {
cflags += [
# Warn on missing break statements at the end of switch cases.
# For intentional fallthrough, use FALLTHROUGH; from
# base/compiler_specific.h
"-Wimplicit-fallthrough",
# Thread safety analysis. See base/thread_annotations.h and
# https://clang.llvm.org/docs/ThreadSafetyAnalysis.html
"-Wthread-safety",
]
}
configs = [ ":default_warnings" ]
}
config("no_chromium_code") {
cflags = []
cflags_cc = []
defines = []
if (is_win) {
cflags += [
"/W3", # Warning level 3.
"/wd4800", # Disable warning when forcing value to bool.
"/wd4267", # TODO(jschuh): size_t to int.
"/wd4996", # Deprecated function warning.
]
defines += [
"_CRT_NONSTDC_NO_WARNINGS",
"_CRT_NONSTDC_NO_DEPRECATE",
]
} else {
# GCC may emit unsuppressible warnings so don't add -Werror for no chromium
# code. crbug.com/589724
if (treat_warnings_as_errors && is_clang) {
cflags += [ "-Werror" ]
ldflags = [ "-Werror" ]
}
if (is_clang && !is_nacl) {
# TODO(thakis): Remove !is_nacl once
# https://codereview.webrtc.org/1552863002/ made its way into chromium.
cflags += [ "-Wall" ]
}
}
if (is_clang) {
cflags += [
# Lots of third-party libraries have unused variables. Instead of
# suppressing them individually, we just blanket suppress them here.
"-Wno-unused-variable",
]
}
configs = [ ":default_warnings" ]
}
# noshadowing -----------------------------------------------------------------
#
# Allows turning -Wshadow on.
config("noshadowing") {
# This flag has to be disabled for nacl because the nacl compiler is too
# strict about shadowing.
if (is_clang && !is_nacl) {
cflags = [ "-Wshadow" ]
}
}
# rtti ------------------------------------------------------------------------
#
# Allows turning Run-Time Type Identification on or off.
config("rtti") {
if (is_win) {
cflags_cc = [ "/GR" ]
} else {
cflags_cc = [ "-frtti" ]
}
}
config("no_rtti") {
# Some sanitizer configs may require RTTI to be left enabled globally
if (!use_rtti) {
if (is_win) {
cflags_cc = [ "/GR-" ]
} else {
cflags_cc = [ "-fno-rtti" ]
cflags_objcc = cflags_cc
}
}
}
# thin_archive -----------------------------------------------------------------
#
# Enables thin archives on posix. Regular archives directly include the object
# files used to generate it. Thin archives merely reference the object files.
# This makes building them faster since it requires less disk IO, but is
# inappropriate if you wish to redistribute your static library.
# This config is added to the global config, so thin archives should already be
# enabled. If you want to make a distributable static library, you need to do 2
# things:
# 1. Set complete_static_lib so that all dependencies of the library make it
# into the library. See `gn help complete_static_lib` for details.
# 2. Remove the thin_archive config, so that the .a file actually contains all
# .o files, instead of just references to .o files in the build directoy
config("thin_archive") {
# Mac and iOS use the mac-specific "libtool" command, not ar, which doesn't
# have a "thin archive" mode (it does accept -T, but it means truncating
# archive names to 16 characters, which is not what we want).
if ((is_posix && !is_nacl && !is_mac && !is_ios) || is_fuchsia) {
arflags = [ "-T" ]
}
}
# exceptions -------------------------------------------------------------------
#
# Allows turning Exceptions on or off.
# Note: exceptions are disallowed in Google code.
config("exceptions") {
if (is_win) {
# Enables exceptions in the STL.
if (!use_custom_libcxx) {
defines = [ "_HAS_EXCEPTIONS=1" ]
}
cflags_cc = [ "/EHsc" ]
} else {
cflags_cc = [ "-fexceptions" ]
cflags_objcc = cflags_cc
}
}
config("no_exceptions") {
if (is_win) {
# Disables exceptions in the STL.
# libc++ uses the __has_feature macro to control whether to use exceptions,
# so defining this macro is unnecessary. Defining _HAS_EXCEPTIONS to 0 also
# breaks libc++ because it depends on MSVC headers that only provide certain
# declarations if _HAS_EXCEPTIONS is 1. Those MSVC headers do not use
# exceptions, despite being conditional on _HAS_EXCEPTIONS.
if (!use_custom_libcxx) {
defines = [ "_HAS_EXCEPTIONS=0" ]
}
} else {
cflags_cc = [ "-fno-exceptions" ]
cflags_objcc = cflags_cc
}
}
# Warnings ---------------------------------------------------------------------
# This will generate warnings when using Clang if code generates exit-time
# destructors, which will slow down closing the program.
# TODO(thakis): Make this a blacklist instead, http://crbug.com/101600
config("wexit_time_destructors") {
# TODO: Enable on Windows too, http://crbug.com/404525
if (is_clang && !is_win) {
cflags = [ "-Wexit-time-destructors" ]
}
}
# On Windows compiling on x64, VC will issue a warning when converting
# size_t to int because it will truncate the value. Our code should not have
# these warnings and one should use a static_cast or a checked_cast for the
# conversion depending on the case. However, a lot of code still needs to be
# fixed. Apply this config to such targets to disable the warning.
#
# Note that this can be applied regardless of platform and architecture to
# clean up the call sites. This will only apply the flag when necessary.
#
# TODO(jschuh): crbug.com/167187 fix this and delete this config.
config("no_size_t_to_int_warning") {
if (is_win && current_cpu == "x64") {
cflags = [ "/wd4267" ]
}
}
# Some code presumes that pointers to structures/objects are compatible
# regardless of whether what they point to is already known to be valid.
# gcc 4.9 and earlier had no way of suppressing this warning without
# suppressing the rest of them. Here we centralize the identification of
# the gcc 4.9 toolchains.
config("no_incompatible_pointer_warnings") {
cflags = []
if (is_clang) {
cflags += [ "-Wno-incompatible-pointer-types" ]
} else if (current_cpu == "mipsel" || current_cpu == "mips64el") {
cflags += [ "-w" ]
} else if (is_chromeos && current_cpu == "arm") {
cflags += [ "-w" ]
}
}
# Optimization -----------------------------------------------------------------
#
# The BUILDCONFIG file sets the "default_optimization" config on targets by
# default. It will be equivalent to either "optimize" (release) or
# "no_optimize" (debug) optimization configs.
#
# You can override the optimization level on a per-target basis by removing the
# default config and then adding the named one you want:
#
# configs -= [ "//build/config/compiler:default_optimization" ]
# configs += [ "//build/config/compiler:optimize_max" ]
# Shared settings for both "optimize" and "optimize_max" configs.
# IMPORTANT: On Windows "/O1" and "/O2" must go before the common flags.
if (is_win) {
common_optimize_on_cflags = [
"/Ob2", # Both explicit and auto inlining.
"/Oy-", # Disable omitting frame pointers, must be after /O2.
"/Zc:inline", # Remove unreferenced COMDAT (faster links).
]
if (!is_asan) {
common_optimize_on_cflags += [
# Put data in separate COMDATs. This allows the linker
# to put bit-identical constants at the same address even if
# they're unrelated constants, which saves binary size.
# This optimization can't be used when ASan is enabled because
# it is not compatible with the ASan ODR checker.
"/Gw",
]
}
common_optimize_on_ldflags = []
# /OPT:ICF is not desirable in Debug builds, since code-folding can result in
# misleading symbols in stack traces. It is also incompatible with
# incremental linking, which we enable for both Debug and component builds.
if (!is_debug && !is_component_build) {
common_optimize_on_ldflags += [ "/OPT:ICF" ] # Redundant COMDAT folding.
}
if (is_official_build) {
common_optimize_on_ldflags += [ "/OPT:REF" ] # Remove unreferenced data.
# TODO(thakis): Remove is_clang here, https://crbug.com/598772
if (!use_lld && !is_clang) {
common_optimize_on_ldflags += [
# Set the number of LTCG code-gen threads to eight. The default is four.
# This gives a 5-10% link speedup.
"/cgthreads:8",
]
if (use_incremental_wpo) {
# Incremental Link-time code generation.
common_optimize_on_ldflags += [ "/LTCG:INCREMENTAL" ]
} else {
common_optimize_on_ldflags += [ "/LTCG" ] # Link-time code generation.
}
if (full_wpo_on_official) {
if (use_incremental_wpo) {
arflags = [ "/LTCG:INCREMENTAL" ]
} else {
arflags = [ "/LTCG" ]
}
}
}
}
} else {
common_optimize_on_cflags = []
common_optimize_on_ldflags = []
if (is_android) {
# TODO(jdduke) Re-enable on mips after resolving linking
# issues with libc++ (crbug.com/456380).
if (current_cpu != "mipsel" && current_cpu != "mips64el") {
common_optimize_on_ldflags += [
# Warn in case of text relocations.
"-Wl,--warn-shared-textrel",
]
}
}
if (is_mac || is_ios) {
if (symbol_level == 2) {
# Mac dead code stripping requires symbols.
common_optimize_on_ldflags += [ "-Wl,-dead_strip" ]
}
} else if (current_os != "aix") {
# Non-Mac Posix flags.
# Aix does not support these.
common_optimize_on_cflags += [
# Don't emit the GCC version ident directives, they just end up in the
# .comment section taking up binary size.
"-fno-ident",
# Put data and code in their own sections, so that unused symbols
# can be removed at link time with --gc-sections.
"-fdata-sections",
"-ffunction-sections",
]
common_optimize_on_ldflags += [
# Specifically tell the linker to perform optimizations.
# See http://lwn.net/Articles/192624/ .
# -O2 enables string tail merge optimization in gold and lld.
"-Wl,-O2",
"-Wl,--gc-sections",
]
}
}
config("default_stack_frames") {
if (is_posix || is_fuchsia) {
if (enable_frame_pointers) {
cflags = [ "-fno-omit-frame-pointer" ]
} else {
cflags = [ "-fomit-frame-pointer" ]
}
}
# On Windows, the flag to enable framepointers "/Oy-" must always come after
# the optimization flag [e.g. "/O2"]. The optimization flag is set by one of
# the "optimize" configs, see rest of this file. The ordering that cflags are
# applied is well-defined by the GN spec, and there is no way to ensure that
# cflags set by "default_stack_frames" is applied after those set by an
# "optimize" config. Similarly, there is no way to propagate state from this
# config into the "optimize" config. We always apply the "/Oy-" config in the
# definition for common_optimize_on_cflags definition, even though this may
# not be correct.
}
# Default "optimization on" config.
config("optimize") {
if (is_win) {
# TODO(thakis): Remove is_clang here, https://crbug.com/598772
if (is_official_build && full_wpo_on_official && !is_clang) {
common_optimize_on_cflags += [
"/GL", # Whole program optimization.
# Disable Warning 4702 ("Unreachable code") for the WPO/PGO builds.
# Probably anything that this would catch that wouldn't be caught in a
# normal build isn't going to actually be a bug, so the incremental
# value of C4702 for PGO builds is likely very small.
"/wd4702",
]
}
# Favor size over speed, /O1 must be before the common flags. The GYP
# build also specifies /Os and /GF but these are implied by /O1.
cflags = [ "/O1" ] + common_optimize_on_cflags + [ "/Oi" ]
} else if (optimize_for_size && !is_nacl) {
# Favor size over speed.
# TODO(crbug.com/718650): Fix -Os in PNaCl compiler and remove the is_nacl
# guard above.
if (is_clang) {
cflags = [ "-Oz" ] + common_optimize_on_cflags
} else {
cflags = [ "-Os" ] + common_optimize_on_cflags
}
} else {
cflags = [ "-O2" ] + common_optimize_on_cflags
}
ldflags = common_optimize_on_ldflags
}
# Same config as 'optimize' but without the WPO flag.
config("optimize_no_wpo") {
if (is_win) {
# Favor size over speed, /O1 must be before the common flags. The GYP
# build also specifies /Os and /GF but these are implied by /O1.
cflags = [ "/O1" ] + common_optimize_on_cflags + [ "/Oi" ]
} else if (optimize_for_size && !is_nacl) {
# Favor size over speed.
# TODO(crbug.com/718650): Fix -Os in PNaCl compiler and remove the is_nacl
# guard above.
if (is_clang) {
cflags = [ "-Oz" ] + common_optimize_on_cflags
} else {
cflags = [ "-Os" ] + common_optimize_on_cflags
}
} else if (optimize_for_fuzzing) {
cflags = [ "-O1" ] + common_optimize_on_cflags
} else {
cflags = [ "-O2" ] + common_optimize_on_cflags
}
ldflags = common_optimize_on_ldflags
}
# Turn off optimizations.
config("no_optimize") {
if (is_win) {
cflags = [
"/Od", # Disable optimization.
"/Ob0", # Disable all inlining (on by default).
"/GF", # Enable string pooling (off by default).
]
} else if (is_android && !android_full_debug) {
# On Android we kind of optimize some things that don't affect debugging
# much even when optimization is disabled to get the binary size down.
if (is_clang) {
cflags = [ "-Oz" ] + common_optimize_on_cflags
} else {
cflags = [ "-Os" ] + common_optimize_on_cflags
}
} else {
cflags = [ "-O0" ]
ldflags = []
}
}
# Turns up the optimization level. On Windows, this implies whole program
# optimization and link-time code generation which is very expensive and should
# be used sparingly.
config("optimize_max") {
if (is_nacl && is_nacl_irt) {
# The NaCl IRT is a special case and always wants its own config.
# Various components do:
# if (!is_debug) {
# configs -= [ "//build/config/compiler:default_optimization" ]
# configs += [ "//build/config/compiler:optimize_max" ]
# }
# So this config has to have the selection logic just like
# "default_optimization", below.
configs = [ "//build/config/nacl:irt_optimize" ]
} else {
ldflags = common_optimize_on_ldflags
if (is_win) {
# Favor speed over size, /O2 must be before the common flags. The GYP
# build also specifies /Ot, /Oi, and /GF, but these are implied by /O2.
cflags = [ "/O2" ] + common_optimize_on_cflags
if (is_official_build) {
if (!is_clang) {
cflags += [
"/GL", # Whole program optimization.
# Disable Warning 4702 ("Unreachable code") for the WPO/PGO builds.
# Probably anything that this would catch that wouldn't be caught
# in a normal build isn't going to actually be a bug, so the
# incremental value of C4702 for PGO builds is likely very small.
"/wd4702",
]
}
# TODO(crbug.com/598772): Enable -flto for Clang.
}
} else if (optimize_for_fuzzing) {
cflags = [ "-O1" ] + common_optimize_on_cflags
} else {
cflags = [ "-O2" ] + common_optimize_on_cflags
}
}
}
# This config can be used to override the default settings for per-component
# and whole-program optimization, optimizing the particular target for speed
# instead of code size. This config is exactly the same as "optimize_max"
# except that we use -O3 instead of -O2 on non-win, non-IRT platforms.
#
# TODO(crbug.com/621335) - rework how all of these configs are related
# so that we don't need this disclaimer.
config("optimize_speed") {
if (is_nacl && is_nacl_irt) {
# The NaCl IRT is a special case and always wants its own config.
# Various components do:
# if (!is_debug) {
# configs -= [ "//build/config/compiler:default_optimization" ]
# configs += [ "//build/config/compiler:optimize_max" ]
# }
# So this config has to have the selection logic just like
# "default_optimization", below.
configs = [ "//build/config/nacl:irt_optimize" ]
} else {
ldflags = common_optimize_on_ldflags
if (is_win) {
# Favor speed over size, /O2 must be before the common flags. The GYP
# build also specifies /Ot, /Oi, and /GF, but these are implied by /O2.
cflags = [ "/O2" ] + common_optimize_on_cflags
# TODO(thakis): Remove is_clang here, https://crbug.com/598772
if (is_official_build && !is_clang) {
cflags += [
"/GL", # Whole program optimization.
# Disable Warning 4702 ("Unreachable code") for the WPO/PGO builds.
# Probably anything that this would catch that wouldn't be caught in a
# normal build isn't going to actually be a bug, so the incremental
# value of C4702 for PGO builds is likely very small.
"/wd4702",
]
}
} else if (optimize_for_fuzzing) {
cflags = [ "-O1" ] + common_optimize_on_cflags
} else {
cflags = [ "-O3" ] + common_optimize_on_cflags
}
}
}
config("optimize_fuzzing") {
cflags = [ "-O1" ] + common_optimize_on_cflags
ldflags = common_optimize_on_ldflags
visibility = [ ":default_optimization" ]
}
# The default optimization applied to all targets. This will be equivalent to
# either "optimize" or "no_optimize", depending on the build flags.
config("default_optimization") {
if (is_nacl && is_nacl_irt) {
# The NaCl IRT is a special case and always wants its own config.
# It gets optimized the same way regardless of the type of build.
configs = [ "//build/config/nacl:irt_optimize" ]
} else if (is_debug) {
configs = [ ":no_optimize" ]
} else if (optimize_for_fuzzing) {
assert(!is_win, "Fuzzing optimize level not supported on Windows")
# Coverage build is quite slow. Using "optimize_for_fuzzing" makes it even
# slower as it uses "-O1" instead of "-O3". Prevent that from happening.
assert(!use_clang_coverage,
"optimize_for_fuzzing=true should not be used with " +
"use_clang_coverage=true.")
configs = [ ":optimize_fuzzing" ]
} else {
configs = [ ":optimize" ]
}
}
_clang_sample_profile = ""
if (is_clang && current_toolchain == default_toolchain) {
if (clang_sample_profile_path != "") {
_clang_sample_profile = clang_sample_profile_path
} else if (clang_use_default_sample_profile) {
assert(build_with_chromium,
"Our default profiles currently only apply to Chromium")
assert(is_android || is_desktop_linux,
"The current platform has no default profile")
_clang_sample_profile = rebase_path("//chrome/android/profiles/afdo.prof")
}
}
# Clang offers a way to assert that AFDO profiles are accurate, which causes it
# to optimize functions not represented in a profile more aggressively for size.
# This config can be toggled in cases where shaving off binary size hurts
# performance too much.
config("afdo_optimize_size") {
if (_clang_sample_profile != "" && sample_profile_is_accurate) {
cflags = [ "-fprofile-sample-accurate" ]
}
}
# GCC and clang support a form of profile-guided optimization called AFDO.
# There are some targeted places that AFDO regresses (and an icky interaction
# between //base/allocator:tcmalloc and AFDO on GCC), so we provide a separate
# config to allow AFDO to be disabled per-target.
config("afdo") {
if (is_clang) {
if (_clang_sample_profile != "") {
cflags = [ "-fprofile-sample-use=${_clang_sample_profile}" ]
inputs = [
_clang_sample_profile,
]
}
} else if (auto_profile_path != "" && current_toolchain == default_toolchain) {
cflags = [ "-fauto-profile=${auto_profile_path}" ]
inputs = [
auto_profile_path,
]
}
}
# Symbols ----------------------------------------------------------------------
# The BUILDCONFIG file sets the "default_symbols" config on targets by
# default. It will be equivalent to one the three specific symbol levels.
#
# You can override the symbol level on a per-target basis by removing the
# default config and then adding the named one you want:
#
# configs -= [ "//build/config/compiler:default_symbols" ]
# configs += [ "//build/config/compiler:symbols" ]
# Full symbols.
config("symbols") {
if (is_win) {
if (use_goma || is_clang) {
# Note that with VC++ this requires is_win_fastlink, enforced elsewhere.
cflags = [ "/Z7" ] # Debug information in the .obj files.
} else {
cflags = [ "/Zi" ] # Produce PDB file, no edit and continue.
}
if (is_win_fastlink && !use_lld) {
# TODO(hans): is_win_fastlink=true is incompatible with use_lld. However,
# some developers might have enabled it manually, so to ease the
# transition to lld, just ignore it rather than asserting. Eventually we
# want to assert instead.
# Tell VS 2015+ to create a PDB that references debug
# information in .obj and .lib files instead of copying
# it all. This flag is incompatible with /PROFILE
ldflags = [ "/DEBUG:FASTLINK" ]
} else if (is_clang && use_lld && use_ghash) {
cflags += [
"-mllvm",
"-emit-codeview-ghash-section",
]
ldflags = [ "/DEBUG:GHASH" ]
} else {
ldflags = [ "/DEBUG" ]
}
if (is_clang) {
# /DEBUG:FASTLINK requires every object file to have standalone debug
# information.
if (is_win_fastlink && !use_lld) {
cflags += [ "-fstandalone-debug" ]
} else {
cflags += [ "-fno-standalone-debug" ]
}
}
} else {
if (is_mac || is_ios) {
cflags = [ "-gdwarf-2" ]
if (is_mac && enable_dsyms) {
# If generating dSYMs, specify -fno-standalone-debug. This was
# originally specified for https://crbug.com/479841 because dsymutil
# could not handle a 4GB dSYM file. But dsymutil from Xcodes prior to
# version 7 also produces debug data that is incompatible with Breakpad
# dump_syms, so this is still required (https://crbug.com/622406).
cflags += [ "-fno-standalone-debug" ]
}
} else {
cflags = []
if (!use_debug_fission && target_cpu == "arm") {
# dump_syms has issues with dwarf4 on arm, https://crbug.com/744956
# TODO(thakis): Remove this again once dump_syms is fixed.
#
# debug fission needs DWARF DIEs to be emitted at version 4.
# Chrome OS emits Debug Frame in DWARF1 to make breakpad happy. [1]
# Unless Android needs debug fission, DWARF3 is the simplest solution.
#
# [1] crrev.com/a81d5ade0b043208e06ad71a38bcf9c348a1a52f
cflags += [ "-gdwarf-3" ]
}
cflags += [ "-g2" ]
}
if (use_debug_fission && !is_nacl && !is_android) {
# NOTE: Some Chrome OS builds globally set |use_debug_fission| to true,
# but they also build some targets against Android toolchains which aren't
# compatible with it.
#
# TODO(https://crbug.com/837032): See if we can clean this up by e.g. not
# setting use_debug_fission globally.
cflags += [ "-gsplit-dwarf" ]
}
asmflags = cflags
ldflags = []
# TODO(thakis): Figure out if there's a way to make this go for 32-bit,
# currently we get "warning:
# obj/native_client/src/trusted/service_runtime/sel_asm/nacl_switch_32.o:
# DWARF info may be corrupt; offsets in a range list entry are in different
# sections" there. Maybe just a bug in nacl_switch_32.S.
if (!is_mac && !is_ios && !is_nacl && target_cpu != "x86" &&
(use_gold || use_lld)) {
if (is_clang) {
# This flag enables the GNU-format pubnames and pubtypes sections,
# which lld needs in order to generate a correct GDB index.
# TODO(pcc): Try to make lld understand non-GNU-format pubnames
# sections (llvm.org/PR34820).
cflags += [ "-ggnu-pubnames" ]
}
ldflags += [ "-Wl,--gdb-index" ]
}
}
}
# Minimal symbols.
# This config guarantees to hold symbol for stack trace which are shown to user
# when crash happens in unittests running on buildbot.
config("minimal_symbols") {
if (is_win) {
# Linker symbols for backtraces only.
cflags = []
ldflags = [ "/DEBUG" ]
} else {
cflags = []
if (target_cpu == "arm") {
# dump_syms has issues with dwarf4 on arm, https://crbug.com/744956
# TODO(thakis): Remove this again once dump_syms is fixed.
cflags += [ "-gdwarf-3" ]
}
cflags += [ "-g1" ]
ldflags = []
if (is_android && is_clang) {
# Android defaults to symbol_level=1 builds in production builds
# (https://crbug.com/648948), but clang, unlike gcc, doesn't emit
# DW_AT_linkage_name in -g1 builds. -fdebug-info-for-profiling enables
# that (and a bunch of other things we don't need), so that we get
# qualified names in stacks.
# TODO(thakis): Consider making clang emit DW_AT_linkage_name in -g1 mode;
# failing that consider doing this on non-Android too.
cflags += [ "-fdebug-info-for-profiling" ]
}
# Note: -gsplit-dwarf implicitly turns on -g2 with clang, so don't pass it.
asmflags = cflags
}
}
# No symbols.
config("no_symbols") {
if (!is_win) {
cflags = [ "-g0" ]
asmflags = cflags
}
}
# Default symbols.
config("default_symbols") {
if (symbol_level == 0) {
configs = [ ":no_symbols" ]
} else if (symbol_level == 1) {
configs = [ ":minimal_symbols" ]
} else if (symbol_level == 2) {
configs = [ ":symbols" ]
} else {
assert(false)
}
# This config is removed by base unittests apk.
if (is_android && is_clang && strip_debug_info) {
configs += [ ":strip_debug" ]
}
}
config("strip_debug") {
if (!defined(ldflags)) {
ldflags = []
}
ldflags += [ "-Wl,--strip-debug" ]
}
if (is_ios || is_mac) {
# On Mac and iOS, this enables support for ARC (automatic ref-counting).
# See http://clang.llvm.org/docs/AutomaticReferenceCounting.html.
config("enable_arc") {
common_flags = [ "-fobjc-arc" ]
cflags_objc = common_flags
cflags_objcc = common_flags
}
}