# 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/sanitizers/sanitizers.gni") import("//build/config/ui.gni") import("//build/toolchain/cc_wrapper.gni") import("//build/toolchain/toolchain.gni") import("//build_overrides/build.gni") # Import features.gni for the "use_qt" argument to be available. import("//build/config/features.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 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_compilation_dir strip_absolute_paths_from_debug_symbols = is_linux && use_goma # Use stdlib=libc++ use_libcxx = is_mac # 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 && !use_clang_coverage && !(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 (use_qt && is_clang) { cflags += [ "-Wno-unknown-attributes", "-Wno-unknown-pragmas", "-Wno-unknown-warning-option" ] cflags_cc += [ "-Wno-parentheses-equality", "-Wno-tautological-compare" ] } if (is_clang && (is_debug || use_qt)) { # 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" ] } if (!is_clang) { # Use pipes for communicating between sub-processes. Faster. # (This flag doesn't do anything with Clang.) 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" && !use_qt) { 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 (symbol_level != 0 && is_clang && !is_nacl && !is_mac && !is_ios && strip_absolute_paths_from_debug_symbols) { # If debug option is given, clang includes $cwd in debug info by default. # For such build, this flag generates reproducible obj files even we use # different build directory like "out/feature_a" and "out/feature_b" if # we build same files with same compile flag. # Other paths are already given in relative, no need to normalize them. cflags += [ "-Xclang", "-fdebug-compilation-dir", "-Xclang", ".", ] } # 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. if (is_clang && !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 (use_libcxx) { 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,$cache_policy", ] } else { ldflags += [ "-Wl,-plugin-opt,jobs=8" ] } } # Disable optimization for now because they increase binary size by too # much. if (use_lld && (is_android || (is_linux && !is_chromeos))) { ldflags += [ "-Wl,--lto-O0" ] } # TODO(pcc): Re-enable this flag on Android. This will require libc++ to be # built with ThinLTO (see https://crbug.com/767901) as well as the GVR shim. if (!is_android) { cflags += [ "-fwhole-program-vtables" ] if (!is_win) { ldflags += [ "-fwhole-program-vtables" ] } } # Work-around for http://openradar.appspot.com/20356002 if (is_mac) { ldflags += [ "-Wl,-all_load" ] } # This flag causes LTO to create an .ARM.attributes section with the correct # architecture. This is necessary because LLD will refuse to link a program # unless the architecture revision in .ARM.attributes is sufficiently new. # TODO(pcc): The contents of .ARM.attributes should be based on the # -march flag passed at compile time (see llvm.org/pr36291). if (current_cpu == "arm") { ldflags += [ "-march=$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" ] } # This flag enforces that member pointer base types are complete. It helps # prevent us from running into problems in the Microsoft C++ ABI (see # https://crbug.com/847724). if (is_clang && !is_nacl && target_os != "chromeos" && !use_xcode_clang && (is_win || use_custom_libcxx)) { cflags += [ "-fcomplete-member-pointers" ] } # 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", ] 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=$arm_tune" ] } } else if (current_cpu == "arm64") { if (is_clang && !is_android && !is_nacl && !is_fuchsia) { cflags += [ "--target=aarch64-linux-gnu" ] ldflags += [ "--target=aarch64-linux-gnu" ] } } else if (current_cpu == "mipsel" && !is_nacl) { ldflags += [ "-Wl,--hash-style=sysv" ] if (custom_toolchain == "") { if (is_clang) { if (is_android) { cflags += [ "--target=mipsel-linux-android" ] ldflags += [ "--target=mipsel-linux-android" ] } else { cflags += [ "--target=mipsel-linux-gnu" ] ldflags += [ "--target=mipsel-linux-gnu" ] } } else { cflags += [ "-EL" ] ldflags += [ "-EL" ] } } if (mips_arch_variant == "r6") { cflags += [ "-mno-odd-spreg" ] ldflags += [ "-mips32r6" ] if (is_clang) { cflags += [ "-march=mipsel", "-mcpu=mips32r6", ] } else { cflags += [ "-mips32r6", "-Wa,-mips32r6", ] if (is_android) { ldflags += [ "-Wl,-melf32ltsmip" ] } } if (mips_use_msa == true) { cflags += [ "-mmsa", "-mfp64", ] } } else if (mips_arch_variant == "r2") { ldflags += [ "-mips32r2" ] if (is_clang) { cflags += [ "-march=mipsel", "-mcpu=mips32r2", ] } else { cflags += [ "-mips32r2", "-Wa,-mips32r2", ] if (mips_float_abi == "hard" && mips_fpu_mode != "") { cflags += [ "-m$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${mips_float_abi}-float" ] } else if (current_cpu == "mips" && !is_nacl) { ldflags += [ "-Wl,--hash-style=sysv" ] if (custom_toolchain == "") { if (is_clang) { cflags += [ "--target=mips-linux-gnu" ] ldflags += [ "--target=mips-linux-gnu" ] } else { cflags += [ "-EB" ] ldflags += [ "-EB" ] } } if (mips_arch_variant == "r6") { cflags += [ "-mips32r6", "-Wa,-mips32r6", ] if (mips_use_msa == true) { cflags += [ "-mmsa", "-mfp64", ] } } else if (mips_arch_variant == "r2") { cflags += [ "-mips32r2", "-Wa,-mips32r2", ] if (mips_float_abi == "hard" && mips_fpu_mode != "") { cflags += [ "-m$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") { ldflags += [ "-Wl,--hash-style=sysv" ] 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") { ldflags += [ "-Wl,--hash-style=sysv" ] 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", # All of our compilers support the extensions below. "/wd4200", # nonstandard extension used: zero-sized array in struct/union "/wd4201", # nonstandard extension used: nameless struct/union "/wd4204", # nonstandard extension used : non-constant aggregate # initializer "/wd4221", # nonstandard extension used : 'identifier' : cannot be # initialized using address of automatic variable # http://crbug.com/588506 - Conversion suppressions waiting on Clang # -Wconversion. "/wd4018", # 'expression' : signed/unsigned mismatch "/wd4245", # 'conversion' : conversion from 'type1' to 'type2', # signed/unsigned mismatch "/wd4267", # 'var' : conversion from 'size_t' to 'type', possible loss of # data "/wd4305", # 'identifier' : truncation from 'type1' to 'type2' "/wd4389", # 'operator' : signed/unsigned mismatch # http://crbug.com/346399 - Unreachable code suppression waiting on Clang # -Wunreachable-code. "/wd4702", # unreachable code # http://crbug.com/848979 - MSVC is more conservative than Clang with # regards to variables initialized and consumed in different branches. "/wd4701", # Potentially uninitialized local variable 'name' used "/wd4703", # Potentially uninitialized local pointer variable 'name' used # http://crbug.com/848979 - Remaining Clang permitted warnings. "/wd4661", # 'identifier' : no suitable definition provided for explicit # template instantiation request "/wd4706", # assignment within conditional expression # MSVC is stricter and requires a boolean expression. "/wd4715", # 'function' : not all control paths return a value' # MSVC does not analyze switch (enum) for completeness. ] 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" ] # Disable a number of GCC warnings caused by a mix # of Chromium and GCC bugs. cflags += [ "-Wno-dangling-else" ] cflags += [ "-Wno-packed-not-aligned" ] cflags_cc += [ "-Wno-attributes" ] cflags_cc += [ "-Wno-class-memaccess" ] cflags_cc += [ "-Wno-subobject-linkage" ] } } # 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) { cflags += [ # TODO(thakis): https://crbug.com/604888 "-Wno-undefined-var-template", # TODO(hans): https://crbug.com/637306 "-Wno-address-of-packed-member", ] if (current_toolchain == host_toolchain || !use_xcode_clang || xcode_version_int >= 930) { cflags += [ # TODO(thakis): https://crbug.com/617318 "-Wno-nonportable-include-path", # TODO(thakis): https://crbug.com/683349 "-Wno-user-defined-warnings", # TODO(hans): https://crbug.com/681136 "-Wno-unused-lambda-capture", ] } if (current_toolchain == host_toolchain || !use_xcode_clang || xcode_version_int >= 1000) { cflags += [ # TODO(hans): https://crbug.com/766891 "-Wno-null-pointer-arithmetic", ] } if (current_toolchain == host_toolchain || !use_xcode_clang) { # Flags NaCl (Clang 3.7) and Xcode 9.2 (Clang clang-900.0.39.2) do not # recognize. cflags += [ # TODO(thakis): https://crbug.com/753973 "-Wno-enum-compare-switch", # Ignore warnings about MSVC optimization pragmas. # TODO(thakis): Only for no_chromium_code? http://crbug.com/505314 "-Wno-ignored-pragma-optimize", ] } } } } # 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. if (is_clang) { # Opt in to additional [[nodiscard]] on standard library methods. defines = [ "_HAS_NODISCARD" ] } } 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. cflags += [ "-U_FORTIFY_SOURCE", "-D_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 = [] } } config("optimize_size_only") { if (is_win) { cflags = [ "/O1" ] } else { cflags = [ "-Os" ] } } # 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 = "//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 != "") { rebased_clang_sample_profile = rebase_path(_clang_sample_profile, root_build_dir) cflags = [ "-fprofile-sample-use=${rebased_clang_sample_profile}" ] inputs = [ _clang_sample_profile, ] } } else if (auto_profile_path != "" && current_toolchain == default_toolchain) { cflags = [ "-fauto-profile=${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 } }