# 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/chrome_build.gni") if (current_cpu == "arm") { import("//build/config/arm.gni") } if (current_cpu == "mipsel" || current_cpu == "mips64el") { import("//build/config/mips.gni") } if (is_posix) { import("//build/config/gcc/gcc_version.gni") } if (is_win) { import("//build/config/win/visual_studio_version.gni") } import("//build/toolchain/ccache.gni") import("//build/config/sanitizers/sanitizers.gni") declare_args() { # 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 = is_linux && current_cpu == "x64" # Compile in such a way as to enable profiling of the generated code. For # example, don't omit the frame pointer and leave in symbols. enable_profiling = false # 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 # Use gold for linking on 64-bit Linux only (on 32-bit it runs out of # address space, and it doesn't support cross-compiling). use_gold = is_linux && current_cpu == "x64" # use_debug_fission: whether to use split DWARF debug info # files. This can reduce link time significantly, but is incompatible # with some utilities such as icecc and ccache. Requires gold and # gcc >= 4.8 or clang. # http://gcc.gnu.org/wiki/DebugFission use_debug_fission = is_debug && !is_win && use_gold && linux_use_bundled_binutils && !use_ccache 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 } } # 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, ] } # TODO(GYP): is_ubsan, is_ubsan_vptr if (!is_win) { using_sanitizer = is_asan || is_lsan || is_tsan || is_msan } # 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") { cflags = [] cflags_c = [] cflags_cc = [] ldflags = [] defines = [] # In general, Windows is totally different, but all the other builds share # some common GCC configuration. This section sets up Windows and the common # GCC flags, and then we handle the other non-Windows platforms specifically # below. if (is_win) { # Windows compiler flags setup. # ----------------------------- cflags += [ "/Gy", # Enable function-level linking. "/GS", # Enable buffer security checking. "/FS", # Preserve previous PDB behavior. ] # Building with Clang on Windows is a work in progress and very # experimental. See crbug.com/82385. # Keep this in sync with the similar block in build/common.gypi if (is_clang) { cflags += [ # Many files use intrinsics without including this header. # TODO(hans): Fix those files, or move this to sub-GYPs. "/FIIntrin.h", ] if (visual_studio_version == "2013") { cflags += [ "-fmsc-version=1800" ] } else if (visual_studio_version == "2015") { cflags += [ "-fmsc-version=1900" ] } if (current_cpu == "x86") { cflags += [ "/fallback", "-m32", ] } else { cflags += [ "-m64" ] } if (exec_script("//build/win/use_ansi_codes.py", [], "trim string") == "True") { cflags += [ # cmd.exe doesn't understand ANSI escape codes by default, # so only enable them if something emulating them is around. "-fansi-escape-codes", ] } } } else { # Common GCC compiler flags setup. # -------------------------------- cflags += [ "-fno-strict-aliasing" ] # See http://crbug.com/32204 cflags_cc += [ "-fno-threadsafe-statics", # Not exporting C++ inline functions can generally be applied anywhere # so we do so here. Normal function visibility is controlled by # //build/config/gcc:symbol_visibility_hidden. "-fvisibility-inlines-hidden", ] # Stack protection. if (is_mac) { cflags += [ "-fstack-protector-all" ] } else if (is_linux) { cflags += [ "-fstack-protector", "--param=ssp-buffer-size=4", ] } # Linker warnings. if (!(is_chromeos && current_cpu == "arm") && !is_mac && !is_ios) { # TODO(jochen): Enable this on chromeos on arm. http://crbug.com/356580 ldflags += [ "-Wl,--fatal-warnings" ] } # Common options for AddressSanitizer, LeakSanitizer, ThreadSanitizer and # MemorySanitizer if (using_sanitizer) { cflags += [ "-fno-omit-frame-pointer", "-gline-tables-only", ] } if (is_asan) { asan_blacklist_path = rebase_path("//tools/memory/asan/blacklist.txt", root_build_dir) cflags += [ "-fsanitize=address", "-fsanitize-blacklist=$asan_blacklist_path", ] if (is_mac) { cflags += [ "-mllvm -asan-globals=0" ] # http://crbug.com/352073 # TODO(GYP): deal with mac_bundles. } } if (is_lsan) { cflags += [ "-fsanitize=leak" ] } if (is_tsan) { tsan_blacklist_path = rebase_path("//tools/memory/tsan_v2/ignores.txt", root_build_dir) cflags += [ "-fsanitize=thread", "-fsanitize-blacklist=$tsan_blacklist_path", ] } if (is_msan) { msan_blacklist_path = rebase_path("//tools/msan/blacklist.txt", root_build_dir) cflags += [ "-fsanitize=memory", "-fsanitize-memory-track-origins=$msan_track_origins", "-fsanitize-blacklist=$msan_blacklist_path", ] } if (use_custom_libcxx) { cflags_cc += [ "-nostdinc++" ] include_dirs = [ "//buildtools/third_party/libc++/trunk/include", "//buildtools/third_party/libc++abi/trunk/include", ] } } 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", ] } if (is_clang && !is_nacl) { # 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=" + exec_script("//tools/clang/scripts/update.py", [ "--print-revision" ], "trim string") ] } # Mac-specific compiler flags setup. # ---------------------------------- if (is_mac || is_ios) { # These flags are shared between the C compiler and linker. common_mac_flags = [] # CPU architecture. if (current_cpu == "x64") { common_mac_flags += [ "-arch", "x86_64", ] } else if (current_cpu == "x86") { common_mac_flags += [ "-arch", "i386", ] } else if (current_cpu == "arm") { common_mac_flags += [ "-arch", "arm64", ] } cflags += common_mac_flags # Without this, the constructors and destructors of a C++ object inside # an Objective C struct won't be called, which is very bad. cflags_objcc = [ "-fobjc-call-cxx-cdtors" ] cflags_c += [ "-std=c99" ] ldflags += common_mac_flags } else if (is_posix) { # Non-Mac Posix compiler flags setup. # ----------------------------------- if (enable_profiling && !is_debug) { # The GYP build spams this define into every compilation unit, as we do # here, but it only appears to be used in base and a couple other places. # TODO(abarth): Should we move this define closer to where it's used? defines += [ "ENABLE_PROFILING" ] cflags += [ "-fno-omit-frame-pointer", "-g", ] if (enable_full_stack_frames_for_profiling) { cflags += [ "-fno-inline", "-fno-optimize-sibling-calls", ] } } # 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_clang) { cflags += [ # Else building libyuv gives clang's register allocator issues, # see llvm.org/PR15798 / crbug.com/233709 "-momit-leaf-frame-pointer", # Align the stack on 16-byte boundaries, http://crbug.com/418554. "-mstack-alignment=16", "-mstackrealign", ] } } else if (current_cpu == "arm") { cflags += [ "-march=$arm_arch", "-mfloat-abi=$arm_float_abi", ] if (arm_tune != "") { cflags += [ "-mtune=$arm_tune" ] } if (arm_use_thumb) { cflags += [ "-mthumb" ] if (is_android && !is_clang) { # Clang doesn't support this option. cflags += [ "-mthumb-interwork" ] } } if (!is_clang) { # Clang doesn't support these flags. cflags += [ # The tree-sra optimization (scalar replacement for # aggregates enabling subsequent optimizations) leads to # invalid code generation when using the Android NDK's # compiler (r5-r7). This can be verified using # webkit_unit_tests' WTF.Checked_int8_t test. "-fno-tree-sra", # The following option is disabled to improve binary # size and performance in gcc 4.9. "-fno-caller-saves", ] } } else if (current_cpu == "mipsel") { if (mips_arch_variant == "r6") { cflags += [ "-mips32r6", "-Wa,-mips32r6", ] if (is_android) { ldflags += [ "-mips32r6", "-Wl,-melf32ltsmip", ] } } else if (mips_arch_variant == "r2") { cflags += [ "-mips32r2", "-Wa,-mips32r2", ] if (mips_float_abi == "hard" && mips_fpu_mode != "") { cflags += [ "-m$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${mips_float_abi}-float" ] } else if (current_cpu == "mips64el") { if (mips_arch_variant == "r6") { cflags += [ "-mips64r6", "-Wa,-mips64r6", ] ldflags += [ "-mips64r6" ] } else if (mips_arch_variant == "r2") { cflags += [ "-mips64r2", "-Wa,-mips64r2", ] ldflags += [ "-mips64r2" ] } } defines += [ "_FILE_OFFSET_BITS=64" ] if (!is_android) { defines += [ "_LARGEFILE_SOURCE", "_LARGEFILE64_SOURCE", ] } # Omit unwind support in official builds to save space. We can use breakpad # for these builds. if (is_chrome_branded && is_official_build) { cflags += [ "-fno-unwind-tables", "-fno-asynchronous-unwind-tables", ] defines += [ "NO_UNWIND_TABLES" ] } else { cflags += [ "-funwind-tables" ] } } # Linux/Android common flags setup. # --------------------------------- if (is_linux || is_android) { cflags += [ "-fPIC", "-pipe", # Use pipes for communicating between sub-processes. Faster. ] ldflags += [ "-fPIC", "-Wl,-z,noexecstack", "-Wl,-z,now", "-Wl,-z,relro", ] if (!using_sanitizer) { ldflags += [ "-Wl,-z,defs" ] } } # Linux-specific compiler flags setup. # ------------------------------------ if (is_linux) { cflags += [ "-pthread" ] ldflags += [ "-pthread" ] } if (use_gold) { gold_path = rebase_path("//third_party/binutils/Linux_x64/Release/bin", root_build_dir) ldflags += [ "-B$gold_path", # Newer gccs and clangs support -fuse-ld, use the flag to force gold # selection. # gcc -- http://gcc.gnu.org/onlinedocs/gcc-4.8.0/gcc/Optimize-Options.html "-fuse-ld=gold", # 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. # TODO(raymes): Disable threading because gold is frequently # crashing on the bots: crbug.com/161942. #"-Wl,--threads", #"-Wl,--thread-count=4", ] if (!is_asan && !is_msan && !is_lsan && !is_tsan) { # TODO(brettw) common.gypi has this only for target toolset. ldflags += [ "-Wl,--icf=all" ] } # 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", # ] #} } if (linux_use_bundled_binutils) { binutils_path = rebase_path("//third_party/binutils/Linux_x64/Release/bin", root_build_dir) cflags += [ "-B$binutils_path" ] } # Clang-specific compiler flags setup. # ------------------------------------ if (is_clang) { cflags += [ "-fcolor-diagnostics" ] } # C++11 compiler flags setup. # --------------------------- if (is_linux || is_android || is_nacl) { # gnu++11 instead of 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_cc += [ "-std=gnu++11" ] } else if (!is_win) { cflags_cc += [ "-std=c++11" ] } # Android-specific flags setup. # ----------------------------- if (is_android) { cflags += [ "-ffunction-sections", "-funwind-tables", "-fno-short-enums", ] if (!is_clang) { # Clang doesn't support these flags. cflags += [ "-finline-limit=64" ] } if (is_asan) { # Android build relies on -Wl,--gc-sections removing unreachable code. # ASan instrumentation for globals inhibits this and results in a library # with unresolvable relocations. # TODO(eugenis): find a way to reenable this. cflags += [ "-mllvm -asan-globals=0" ] } defines += [ "ANDROID" ] # The NDK has these things, but doesn't define the constants # to say that it does. Define them here instead. defines += [ "HAVE_SYS_UIO_H" ] # Use gold for Android for most CPU architectures. if (current_cpu == "x86" || current_cpu == "x64" || current_cpu == "arm") { ldflags += [ "-fuse-ld=gold" ] if (is_clang) { # Let clang find the ld.gold in the NDK. ldflags += [ "--gcc-toolchain=" + rebase_path(android_toolchain_root, root_build_dir) ] } } ldflags += [ "-Wl,--no-undefined", # Don't allow visible symbols from libgcc or libc++ to be # re-exported. "-Wl,--exclude-libs=libgcc.a", "-Wl,--exclude-libs=libc++_static.a", # Don't allow visible symbols from libraries that contain # assembly code with symbols that aren't hidden properly. # http://crbug.com/448386 "-Wl,--exclude-libs=libvpx_assembly_arm.a", ] if (current_cpu == "arm") { ldflags += [ # Enable identical code folding to reduce size. "-Wl,--icf=safe", ] } if (is_clang) { if (current_cpu == "arm") { cflags += [ "-target arm-linux-androideabi" ] ldflags += [ "-target arm-linux-androideabi" ] } else if (current_cpu == "x86") { cflags += [ "-target x86-linux-androideabi" ] ldflags += [ "-target x86-linux-androideabi" ] } } } } config("compiler_arm_fpu") { if (current_cpu == "arm" && !is_ios) { cflags = [ "-mfpu=$arm_fpu" ] } } # 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") { cflags = [] defines = [] ldflags = [] lib_dirs = [] libs = [] if (is_component_build) { # Component mode: dynamic CRT. defines += [ "COMPONENT_BUILD" ] if (is_win) { # Since the library is shared, it requires exceptions or will give errors # about things not matching, so keep exceptions on. if (is_debug) { cflags += [ "/MDd" ] } else { cflags += [ "/MD" ] } } } else { # Static CRT. if (is_win) { if (is_debug) { cflags += [ "/MTd" ] } else { cflags += [ "/MT" ] } } } if (is_win) { defines += [ "__STD_C", "_CRT_RAND_S", "_CRT_SECURE_NO_DEPRECATE", "_HAS_EXCEPTIONS=0", "_SCL_SECURE_NO_DEPRECATE", ] } # Android standard library setup. if (is_android) { if (is_clang) { # Work around incompatibilities between bionic and clang headers. defines += [ "__compiler_offsetof=__builtin_offsetof", "nan=__builtin_nan", ] } defines += [ "__GNU_SOURCE=1" ] # Necessary for clone(). # TODO(jdduke) Re-enable on mips after resolving linking # issues with libc++ (crbug.com/456380). if (current_cpu != "mipsel" && current_cpu != "mips64el") { ldflags += [ "-Wl,--warn-shared-textrel" ] } ldflags += [ "-nostdlib" ] # NOTE: The libc++ header include paths below are specified in cflags # rather than include_dirs because they need to come after include_dirs. # Think of them like system headers, but don't use '-isystem' because the # arm-linux-androideabi-4.4.3 toolchain (circa Gingerbread) will exhibit # strange errors. The include ordering here is important; change with # caution. cflags += [ "-isystem" + rebase_path("$android_libcpp_root/libcxx/include", root_build_dir), "-isystem" + rebase_path( "$android_ndk_root/sources/cxx-stl/llvm-libc++abi/libcxxabi/include", root_build_dir), "-isystem" + rebase_path("$android_ndk_root/sources/android/support/include", root_build_dir), ] lib_dirs += [ "$android_libcpp_root/libs/$android_app_abi" ] libs += [ "$android_libcpp_library" ] if (current_cpu == "mipsel") { libs += [ # ld linker is used for mips Android, and ld does not accept library # absolute path prefixed by "-l"; Since libgcc does not exist in mips # sysroot the proper library will be linked. # TODO(gordanac): Remove once gold linker is used for mips Android. "gcc", ] } else { libs += [ # Manually link the libgcc.a that the cross compiler uses. This is # absolute because the linker will look inside the sysroot if it's not. rebase_path(android_libgcc_file), ] } libs += [ "c", "dl", "m", ] # Clang with libc++ does not require an explicit atomic library reference. if (!is_clang) { libs += [ "atomic" ] } } } # default_warning_flags collects all warning flags that are used by default. # This is in a variable instead of a config so that it can be used in # both chromium_code and no_chromium_code. This way these flags are guaranteed # to appear on the compile command line after -Wall. default_warning_flags = [] default_warning_flags_cc = [] if (is_win) { if (!is_clang || current_cpu != "x86") { default_warning_flags += [ "/WX" ] # Treat warnings as errors. } default_warning_flags += [ # Warnings permanently disabled: # TODO(GYP) The GYP build doesn't have this globally enabled but disabled # for a bunch of individual targets. Re-enable this globally when those # targets are fixed. "/wd4018", # Comparing signed and unsigned values. # 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", # 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. "/wd4481", # Nonstandard extension: override specifier. "/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. "/wd4996", # Deprecated function warning. ] # 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) { default_warning_flags += [ "/wd4702" ] # Unreachable code. } # Building with Clang on Windows is a work in progress and very # experimental. See crbug.com/82385. # Keep this in sync with the similar block in build/common.gypi if (is_clang) { default_warning_flags += [ # TODO(hans): Make this list shorter eventually, http://crbug.com/504657 "-Qunused-arguments", # http://crbug.com/504658 "-Wno-microsoft", # http://crbug.com/505296 "-Wno-switch", # http://crbug.com/505308 "-Wno-unknown-pragmas", # http://crbug.com/505314 "-Wno-unused-function", # http://crbug.com/505316 "-Wno-unused-value", # http://crbug.com/505318 "-Wno-unused-local-typedef", # http://crbug.com/411648 ] } } else { # Common GCC warning setup. default_warning_flags += [ # Enables. "-Wendif-labels", # Weird old-style text after an #endif. "-Werror", # Warnings as errors. # Disables. "-Wno-missing-field-initializers", # "struct foo f = {0};" "-Wno-unused-parameter", # Unused function parameters. ] if (is_mac) { default_warning_flags += [ "-Wnewline-eof" ] if (!is_nacl) { # When compiling Objective-C, warns if a method is used whose # availability is newer than the deployment target. This is not # required when compiling Chrome for iOS. default_warning_flags += [ "-Wpartial-availability" ] } } if (gcc_version >= 48) { default_warning_flags_cc += [ # See comment for -Wno-c++11-narrowing. "-Wno-narrowing", # TODO(thakis): Remove, http://crbug.com/263960 "-Wno-literal-suffix", ] } # Suppress warnings about ABI changes on ARM (Clang doesn't give this # warning). if (current_cpu == "arm" && !is_clang) { default_warning_flags += [ "-Wno-psabi" ] } if (is_android) { # Disable any additional warnings enabled by the Android build system but # which chromium does not build cleanly with (when treating warning as # errors). default_warning_flags += [ "-Wno-extra", "-Wno-ignored-qualifiers", "-Wno-type-limits", ] default_warning_flags_cc += [ # Disabling c++0x-compat should be handled in WebKit, but # this currently doesn't work because gcc_version is not set # correctly when building with the Android build system. # TODO(torne): Fix this in WebKit. "-Wno-error=c++0x-compat", # Other things unrelated to -Wextra: "-Wno-non-virtual-dtor", "-Wno-sign-promo", ] } if (gcc_version >= 48) { # Don't warn about the "typedef 'foo' locally defined but not used" # for gcc 4.8. # TODO: remove this flag once all builds work. See crbug.com/227506 default_warning_flags += [ "-Wno-unused-local-typedefs" ] } } if (is_clang) { default_warning_flags += [ # 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", # Don't die on dtoa code that uses a char as an array index. # This is required solely for base/third_party/dmg_fp/dtoa.cc. # TODO(brettw) move this to that project then! "-Wno-char-subscripts", # 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", # Clang considers the `register` keyword as deprecated, but e.g. # code generated by flex (used in angle) contains that keyword. # http://crbug.com/255186 "-Wno-deprecated-register", # 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", # TODO(thakis): Remove, http://crbug.com/263960 "-Wno-reserved-user-defined-literal", ] # NaCl's Clang compiler and Chrome's hermetic Clang compiler will almost # always have different versions. Certain flags may not be recognized by # one version or the other. if (!is_nacl) { # Flags NaCl does not recognize. default_warning_flags += [ # TODO(hans): Get this cleaned up, http://crbug.com/428099 "-Wno-inconsistent-missing-override", # TODO(thakis): Enable this, crbug.com/507717 "-Wno-shift-negative-value", ] } } # 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", # GCC turns on -Wsign-compare for C++ under -Wall, but clang doesn't, # so we specify it explicitly. # TODO(fischman): remove this if http://llvm.org/PR10448 obsoletes it. # http://code.google.com/p/chromium/issues/detail?id=90453 "-Wsign-compare", ] # 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 (!using_sanitizer && (!is_linux || !is_clang || is_official_build)) { # _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" ] } } cflags += default_warning_flags cflags_cc = default_warning_flags_cc } 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", ] } if (is_linux) { # Don't warn about ignoring the return value from e.g. close(). This is # off by default in some gccs but on by default in others. BSD systems do # not support this option, since they are usually using gcc 4.2.1, which # does not have this flag yet. cflags += [ "-Wno-unused-result" ] } if (is_clang) { cflags += [ # TODO(mgiuca): Move this suppression into individual third-party # libraries as required. http://crbug.com/505301. "-Wno-overloaded-virtual", # Lots of third-party libraries have unused variables. Instead of # suppressing them individually, we just blanket suppress them here. "-Wno-unused-variable", ] } if (is_linux || is_android) { cflags += [ # Don't warn about printf format problems. This is off by default in gcc # but on in Ubuntu's gcc(!). "-Wno-format", ] cflags_cc += [ # Don't warn about hash_map in third-party code. "-Wno-deprecated", ] } cflags += default_warning_flags cflags_cc += default_warning_flags_cc } # rtti ------------------------------------------------------------------------ # # Allows turning Run-Time Type Identification on or off. config("rtti") { if (is_win) { cflags_cc = [ "/GR" ] } } config("no_rtti") { if (is_win) { cflags_cc = [ "/GR-" ] } else { cflags_cc = [ "-fno-rtti" ] } } # 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" ] } } # Optimization ----------------------------------------------------------------- # # Note that BUILDCONFIG.gn sets up a variable "default_optimization_config" # which it will assign to the config it implicitly applies to every target. If # you want to override the optimization level for your target, remove this # config (which will expand differently for debug or release builds), and then # add back the one you want to override it with: # # configs -= default_optimization_config # 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. ] 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:REF" ] } else { 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 = [] if (is_android) { if (!using_sanitizer) { common_optimize_on_cflags += [ "-fomit-frame-pointer" ] } # 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) { if (symbol_level == 2) { # Mac dead code stripping requires symbols. common_optimize_on_ldflags += [ "-Wl,-dead_strip" ] } } else { # Non-Mac Posix linker flags. common_optimize_on_ldflags += [ # Specifically tell the linker to perform optimizations. # See http://lwn.net/Articles/192624/ . "-Wl,-O1", "-Wl,--gc-sections", ] if (!using_sanitizer) { # Functions interposed by the sanitizers can make ld think # that some libraries aren't needed when they actually are, # http://crbug.com/234010. As workaround, disable --as-needed. common_optimize_on_ldflags += [ "-Wl,--as-needed" ] } } } # Default "optimization on" config. On Windows, this favors size over speed. config("optimize") { 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 (is_android || is_ios) { cflags = [ "-Os" ] + common_optimize_on_cflags # Favor size over speed. } 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). "/RTC1", # Runtime checks for stack frame and uninitialized variables. ] } 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. cflags = [ "-Os", "-fdata-sections", "-ffunction-sections", ] if (!using_sanitizer) { cflags += [ "-fomit-frame-pointer" ] } ldflags = common_optimize_on_ldflags } else { cflags = [ "-O0" ] } } # 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") { 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) { # TODO(GYP): TODO(dpranke): Should these only be on in an official # build, or on all the time? For now we'll require official build so # that the compile is clean. 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", ] ldflags += [ "/LTCG" ] } } else { cflags = [ "-O2" ] + common_optimize_on_cflags } } # Symbols ---------------------------------------------------------------------- config("symbols") { if (is_win) { import("//build/toolchain/goma.gni") if (use_goma) { cflags = [ "/Z7" ] # No PDB file } else { cflags = [ "/Zi" ] # Produce PDB file, no edit and continue. } ldflags = [ "/DEBUG" ] } else { cflags = [ "-g2" ] if (use_debug_fission) { cflags += [ "-gsplit-dwarf" ] } } } config("minimal_symbols") { if (is_win) { # Linker symbols for backtraces only. ldflags = [ "/DEBUG" ] } else { cflags = [ "-g1" ] if (use_debug_fission) { cflags += [ "-gsplit-dwarf" ] } } } config("no_symbols") { if (!is_win) { cflags = [ "-g0" ] } }