tor-browser

The Tor Browser
git clone https://git.dasho.dev/tor-browser.git
Log | Files | Refs | README | LICENSE

BUILDCONFIG.gn (32551B)


      1 # Copyright 2013 The Chromium Authors
      2 # Use of this source code is governed by a BSD-style license that can be
      3 # found in the LICENSE file.
      4 
      5 # =============================================================================
      6 # WHAT IS THIS FILE?
      7 # =============================================================================
      8 #
      9 # This is the main GN build configuration. This file is loaded after the
     10 # build args (args.gn) for the build directory and after the toplevel ".gn"
     11 # file (which points to this file as the build configuration).
     12 #
     13 # This file will be executed and the resulting context will be used to execute
     14 # every other file in the build. So variables declared here (that don't start
     15 # with an underscore) will be implicitly global.
     16 
     17 # =============================================================================
     18 # PLATFORM SELECTION
     19 # =============================================================================
     20 #
     21 # There are two main things to set: "os" and "cpu". The "toolchain" is the name
     22 # of the GN thing that encodes combinations of these things.
     23 #
     24 # Users typically only set the variables "target_os" and "target_cpu" in "gn
     25 # args", the rest are set up by our build and internal to GN.
     26 #
     27 # There are three different types of each of these things: The "host"
     28 # represents the computer doing the compile and never changes. The "target"
     29 # represents the main thing we're trying to build. The "current" represents
     30 # which configuration is currently being defined, which can be either the
     31 # host, the target, or something completely different (like nacl). GN will
     32 # run the same build file multiple times for the different required
     33 # configuration in the same build.
     34 #
     35 # This gives the following variables:
     36 #  - host_os, host_cpu, host_toolchain
     37 #  - target_os, target_cpu, default_toolchain
     38 #  - current_os, current_cpu, current_toolchain.
     39 #
     40 # Note the default_toolchain isn't symmetrical (you would expect
     41 # target_toolchain). This is because the "default" toolchain is a GN built-in
     42 # concept, and "target" is something our build sets up that's symmetrical with
     43 # its GYP counterpart. Potentially the built-in default_toolchain variable
     44 # could be renamed in the future.
     45 #
     46 # When writing build files, to do something only for the host:
     47 #   if (current_toolchain == host_toolchain) { ...
     48 
     49 if (target_os == "") {
     50   target_os = host_os
     51 }
     52 
     53 if (target_cpu == "") {
     54   if (target_os == "android") {
     55     # If we're building for Android, we should assume that we want to
     56     # build for ARM by default, not the host_cpu (which is likely x64).
     57     # This allows us to not have to specify both target_os and target_cpu
     58     # on the command line.
     59     target_cpu = "arm"
     60   } else {
     61     target_cpu = host_cpu
     62   }
     63 }
     64 
     65 if (current_cpu == "") {
     66   current_cpu = target_cpu
     67 }
     68 if (current_os == "") {
     69   current_os = target_os
     70 }
     71 
     72 # =============================================================================
     73 # BUILD FLAGS
     74 # =============================================================================
     75 #
     76 # This block lists input arguments to the build, along with their default
     77 # values.
     78 #
     79 # If a value is specified on the command line, it will overwrite the defaults
     80 # given in a declare_args block, otherwise the default will be used.
     81 #
     82 # YOU SHOULD ALMOST NEVER NEED TO ADD FLAGS TO THIS FILE. GN allows any file in
     83 # the build to declare build flags. If you need a flag for a single component,
     84 # you can just declare it in the corresponding BUILD.gn file.
     85 #
     86 # - If your feature is a single target, say //components/foo, you can put
     87 #   a declare_args() block in //components/foo/BUILD.gn and use it there.
     88 #   Nobody else in the build needs to see the flag.
     89 #
     90 # - Defines based on build variables should be implemented via the generated
     91 #   build flag header system. See //build/buildflag_header.gni. You can put
     92 #   the buildflag_header target in the same file as the build flag itself. You
     93 #   should almost never set "defines" directly.
     94 #
     95 # - If your flag toggles a target on and off or toggles between different
     96 #   versions of similar things, write a "group" target that forwards to the
     97 #   right target (or no target) depending on the value of the build flag. This
     98 #   group can be in the same BUILD.gn file as the build flag, and targets can
     99 #   depend unconditionally on the group rather than duplicating flag checks
    100 #   across many targets.
    101 #
    102 # - If a semi-random set of build files REALLY needs to know about a define and
    103 #   the above pattern for isolating the build logic in a forwarding group
    104 #   doesn't work, you can put the argument in a .gni file. This should be put
    105 #   in the lowest level of the build that knows about this feature (which should
    106 #   almost always be outside of the //build directory!).
    107 #
    108 # Other flag advice:
    109 #
    110 # - Use boolean values when possible. If you need a default value that expands
    111 #   to some complex thing in the default case (like the location of the
    112 #   compiler which would be computed by a script), use a default value of -1 or
    113 #   the empty string. Outside of the declare_args block, conditionally expand
    114 #   the default value as necessary.
    115 #
    116 # - Use a name like "use_foo" or "is_foo" (whatever is more appropriate for
    117 #   your feature) rather than just "foo".
    118 #
    119 # - Write good comments directly above the declaration with no blank line.
    120 #   These comments will appear as documentation in "gn args --list".
    121 #
    122 # - Don't call exec_script inside declare_args. This will execute the script
    123 #   even if the value is overridden, which is wasteful. See first bullet.
    124 
    125 declare_args() {
    126   # Set to enable the official build level of optimization. This has nothing
    127   # to do with branding, but enables an additional level of optimization above
    128   # release (!is_debug). This might be better expressed as a tri-state
    129   # (debug, release, official) but for historical reasons there are two
    130   # separate flags.
    131   #
    132   # IMPORTANT NOTE: (!is_debug) is *not* sufficient to get satisfying
    133   # performance. In particular, DCHECK()s are still enabled for release builds,
    134   # which can halve overall performance, and do increase memory usage. Always
    135   # set "is_official_build" to true for any build intended to ship to end-users.
    136   is_official_build = false
    137 
    138   # Set to true when compiling with the Clang compiler.
    139   is_clang = current_os != "linux" || current_os == "openbsd" ||
    140              (current_cpu != "s390x" && current_cpu != "s390" &&
    141               current_cpu != "ppc64" && current_cpu != "ppc" &&
    142               current_cpu != "mips" && current_cpu != "mips64" &&
    143               current_cpu != "riscv64")
    144 
    145   # Allows the path to a custom target toolchain to be injected as a single
    146   # argument, and set as the default toolchain.
    147   custom_toolchain = ""
    148 
    149   # This should not normally be set as a build argument.  It's here so that
    150   # every toolchain can pass through the "global" value via toolchain_args().
    151   host_toolchain = ""
    152 
    153   # Do not set this directly.
    154   # It should be set only by //build/toolchains/android:robolectric_x64.
    155   # True when compiling native code for use with robolectric_binary().
    156   is_robolectric = false
    157 
    158   # DON'T ADD MORE FLAGS HERE. Read the comment above.
    159 }
    160 
    161 declare_args() {
    162   # Debug build. Enabling official builds automatically sets is_debug to false.
    163   is_debug = !is_official_build
    164 }
    165 
    166 declare_args() {
    167   # Component build. Setting to true compiles targets declared as "components"
    168   # as shared libraries loaded dynamically. This speeds up development time.
    169   # When false, components will be linked statically.
    170   #
    171   # For more information see
    172   # https://chromium.googlesource.com/chromium/src/+/main/docs/component_build.md
    173   is_component_build =
    174       is_debug && current_os != "ios" && current_os != "watchos"
    175 }
    176 
    177 assert(!(is_debug && is_official_build), "Can't do official debug builds")
    178 assert(!(current_os == "ios" && is_component_build),
    179        "Can't use component build on iOS")
    180 assert(!(current_os == "watchos" && is_component_build),
    181        "Can't use component build on watchOS")
    182 
    183 declare_args() {
    184   # Unsafe buffers. Location of file used by plugins to track portions of
    185   # the codebase which have been made manifestly safe.
    186   clang_unsafe_buffers_paths = ""
    187   clang_warning_suppression_file = ""
    188 }
    189 
    190 # ==============================================================================
    191 # TOOLCHAIN SETUP
    192 # ==============================================================================
    193 #
    194 # Here we set the default toolchain, as well as the variable host_toolchain
    195 # which will identify the toolchain corresponding to the local system when
    196 # doing cross-compiles. When not cross-compiling, this will be the same as the
    197 # default toolchain.
    198 #
    199 # We do this before anything else to make sure we complain about any
    200 # unsupported os/cpu combinations as early as possible.
    201 
    202 if (host_toolchain == "") {
    203   # This should only happen in the top-level context.
    204   # In a specific toolchain context, the toolchain_args()
    205   # block should have propagated a value down.
    206   # TODO(dpranke): Add some sort of assert here that verifies that
    207   # no toolchain omitted host_toolchain from its toolchain_args().
    208 
    209   if (host_os == "linux" || host_os == "openbsd") {
    210     if (target_os != "linux") {
    211       host_toolchain = "//chromium/build/toolchain/linux:clang_$host_cpu"
    212     } else if (is_clang) {
    213       host_toolchain = "//chromium/build/toolchain/linux:clang_$host_cpu"
    214     } else {
    215       host_toolchain = "//chromium/build/toolchain/linux:$host_cpu"
    216     }
    217   } else if (host_os == "mac") {
    218     host_toolchain = "//chromium/build/toolchain/mac:clang_$host_cpu"
    219   } else if (host_os == "win") {
    220     # On Windows always use the target CPU for host builds for x86/x64. On the
    221     # configurations we support this will always work and it saves build steps.
    222     # Windows ARM64 targets require an x64 host for cross build.
    223     if (target_cpu == "x86" || target_cpu == "x64") {
    224       if (is_clang) {
    225         host_toolchain = "//chromium/build/toolchain/win:win_clang_$target_cpu"
    226       } else {
    227         host_toolchain = "//chromium/build/toolchain/win:$target_cpu"
    228       }
    229     } else if (is_clang) {
    230       host_toolchain = "//chromium/build/toolchain/win:win_clang_$host_cpu"
    231     } else {
    232       host_toolchain = "//chromium/build/toolchain/win:$host_cpu"
    233     }
    234   } else if (host_os == "aix") {
    235     host_toolchain = "//chromium/build/toolchain/aix:$host_cpu"
    236   } else if (host_os == "zos") {
    237     host_toolchain = "//chromium/build/toolchain/zos:$host_cpu"
    238   } else {
    239     assert(false, "Unsupported host_os: $host_os")
    240   }
    241 }
    242 
    243 _default_toolchain = ""
    244 
    245 if (target_os == "android") {
    246   # Targeting android on Mac is best-effort and not guaranteed to work.
    247   #assert(host_os == "linux", "Android builds are only supported on Linux.")
    248   _default_toolchain = "//chromium/build/toolchain/android:android_clang_$target_cpu"
    249 } else if (target_os == "chromeos" || target_os == "linux" || target_os == "openbsd") {
    250   # See comments in build/toolchain/cros/BUILD.gn about board compiles.
    251   if (is_clang) {
    252     _default_toolchain = "//chromium/build/toolchain/linux:clang_$target_cpu"
    253   } else {
    254     _default_toolchain = "//chromium/build/toolchain/linux:$target_cpu"
    255   }
    256 } else if (target_os == "fuchsia") {
    257   _default_toolchain = "//chromium/build/toolchain/fuchsia:$target_cpu"
    258 } else if (target_os == "ios") {
    259   _default_toolchain = "//chromium/build/toolchain/ios:ios_clang_$target_cpu"
    260 } else if (target_os == "mac") {
    261   #assert(host_os == "mac" || host_os == "linux",
    262   #       "Mac cross-compiles are unsupported.")
    263   _default_toolchain = "//chromium/build/toolchain/mac:clang_$target_cpu"
    264 } else if (target_os == "win") {
    265   # On Windows, we use the same toolchain for host and target by default.
    266   # Beware, win cross builds have some caveats, see docs/win_cross.md
    267   if (is_clang) {
    268     _default_toolchain = "//chromium/build/toolchain/win:win_clang_$target_cpu"
    269   } else {
    270     _default_toolchain = "//chromium/build/toolchain/win:$target_cpu"
    271   }
    272 } else if (target_os == "winuwp") {
    273   # Only target WinUWP on for a Windows store application and only
    274   # x86, x64 and arm are supported target CPUs.
    275   assert(target_cpu == "x86" || target_cpu == "x64" || target_cpu == "arm" ||
    276          target_cpu == "arm64")
    277   _default_toolchain = "//chromium/build/toolchain/win:uwp_$target_cpu"
    278 } else if (target_os == "aix") {
    279   _default_toolchain = "//chromium/build/toolchain/aix:$target_cpu"
    280 } else if (target_os == "zos") {
    281   _default_toolchain = "//chromium/build/toolchain/zos:$target_cpu"
    282 } else {
    283   assert(false, "Unsupported target_os: $target_os")
    284 }
    285 
    286 # If a custom toolchain has been set in the args, set it as default. Otherwise,
    287 # set the default toolchain for the platform (if any).
    288 if (custom_toolchain != "") {
    289   set_default_toolchain(custom_toolchain)
    290 } else if (_default_toolchain != "") {
    291   set_default_toolchain(_default_toolchain)
    292 }
    293 
    294 # =============================================================================
    295 # OS DEFINITIONS
    296 # =============================================================================
    297 #
    298 # We set these various is_FOO booleans for convenience in writing OS-based
    299 # conditions.
    300 #
    301 # - is_android, is_chromeos, is_ios, and is_win should be obvious.
    302 # - is_mac is set only for desktop Mac. It is not set on iOS.
    303 # - is_posix is true for mac and any Unix-like system (basically everything
    304 #   except Fuchsia and Windows).
    305 # - is_linux is true for desktop Linux, but not for ChromeOS nor Android (which
    306 #   is generally too different despite being based on the Linux kernel).
    307 #
    308 # Do not add more is_* variants here for random lesser-used Unix systems like
    309 # aix or one of the BSDs. If you need to check these, just check the
    310 # current_os value directly.
    311 
    312 is_android = current_os == "android"
    313 is_chromeos = current_os == "chromeos"
    314 is_fuchsia = current_os == "fuchsia"
    315 is_ios = current_os == "ios"
    316 is_linux = current_os == "linux"
    317 is_bsd = current_os == "openbsd"
    318 is_mac = current_os == "mac"
    319 is_nacl = current_os == "nacl"
    320 is_wasm = current_os == "emscripten"
    321 is_watchos = current_os == "watchos"
    322 is_win = current_os == "win" || current_os == "winuwp"
    323 
    324 is_apple = is_ios || is_mac || is_watchos
    325 is_posix = !is_win && !is_fuchsia
    326 
    327 # =============================================================================
    328 # TARGET DEFAULTS
    329 # =============================================================================
    330 #
    331 # Set up the default configuration for every build target of the given type.
    332 # The values configured here will be automatically set on the scope of the
    333 # corresponding target. Target definitions can add or remove to the settings
    334 # here as needed.
    335 #
    336 # WHAT GOES HERE?
    337 #
    338 # Other than the main compiler and linker configs, the only reason for a config
    339 # to be in this list is if some targets need to explicitly override that config
    340 # by removing it. This is how targets opt-out of flags. If you don't have that
    341 # requirement and just need to add a config everywhere, reference it as a
    342 # sub-config of an existing one, most commonly the main "compiler" one.
    343 
    344 # Holds all configs used for running the compiler.
    345 default_compiler_configs = [
    346   "//chromium/build/config:feature_flags",
    347   "//chromium/build/config/compiler:afdo",
    348   "//chromium/build/config/compiler:afdo_optimize_size",
    349   "//chromium/build/config/compiler:cet_shadow_stack",
    350   "//chromium/build/config/compiler:chromium_code",
    351   "//chromium/build/config/compiler:compiler",
    352   "//chromium/build/config/compiler:compiler_arm_fpu",
    353   "//chromium/build/config/compiler:compiler_arm_thumb",
    354   "//chromium/build/config/compiler:default_include_dirs",
    355   "//chromium/build/config/compiler:default_init_stack_vars",
    356   "//chromium/build/config/compiler:default_optimization",
    357   "//chromium/build/config/compiler:default_stack_frames",
    358   "//chromium/build/config/compiler:default_symbols",
    359   "//chromium/build/config/compiler:disallow_unstable_features",
    360   "//chromium/build/config/compiler:libcxx_hardening",
    361   "//chromium/build/config/compiler:libcxx_module",
    362   "//chromium/build/config/compiler:no_exceptions",
    363   "//chromium/build/config/compiler:no_rtti",
    364   "//chromium/build/config/compiler:no_unresolved_symbols",
    365   "//chromium/build/config/compiler:runtime_library",
    366   "//chromium/build/config/compiler:thin_archive",
    367   "//chromium/build/config/compiler:thinlto_optimize_default",
    368   "//chromium/build/config/compiler/pgo:default_pgo_flags",
    369   "//chromium/build/config/coverage:default_coverage",
    370   "//chromium/build/config/sanitizers:default_sanitizer_flags",
    371 ]
    372 
    373 if (is_win) {
    374   default_compiler_configs += [
    375     "//chromium/build/config/win:default_cfg_compiler",
    376     "//chromium/build/config/win:default_crt",
    377     "//chromium/build/config/win:lean_and_mean",
    378     "//chromium/build/config/win:nominmax",
    379     "//chromium/build/config/win:unicode",
    380     "//chromium/build/config/win:winver",
    381   ]
    382 }
    383 
    384 if (is_apple) {
    385   default_compiler_configs += [ "//chromium/build/config/compiler:enable_arc" ]
    386 }
    387 
    388 if (is_posix) {
    389   if (current_os != "aix") {
    390     default_compiler_configs +=
    391         [ "//chromium/build/config/gcc:symbol_visibility_hidden" ]
    392   }
    393 }
    394 
    395 if (is_fuchsia) {
    396   default_compiler_configs += [ "//chromium/build/config/gcc:symbol_visibility_hidden" ]
    397 }
    398 
    399 if (is_android) {
    400   default_compiler_configs +=
    401       [ "//chromium/build/config/android:default_orderfile_instrumentation" ]
    402 }
    403 
    404 if (is_clang && !is_nacl) {
    405   default_compiler_configs += [
    406     "//chromium/build/config/clang:extra_warnings",
    407     "//chromium/build/config/clang:find_bad_constructs",
    408     "//chromium/build/config/clang:unsafe_buffers",
    409   ]
    410 }
    411 
    412 # Debug/release-related defines.
    413 if (is_debug) {
    414   default_compiler_configs += [ "//chromium/build/config:debug" ]
    415 } else {
    416   default_compiler_configs += [ "//chromium/build/config:release" ]
    417 }
    418 
    419 # Static libraries and source sets use only the compiler ones.
    420 set_defaults("static_library") {
    421   configs = default_compiler_configs
    422 }
    423 set_defaults("source_set") {
    424   configs = default_compiler_configs
    425 }
    426 set_defaults("rust_library") {
    427   configs = default_compiler_configs
    428 }
    429 
    430 # Compute the set of configs common to all linked targets (shared libraries,
    431 # loadable modules, executables) to avoid duplication below.
    432 if (is_win) {
    433   # Many targets remove these configs, so they are not contained within
    434   # //build/config:executable_config for easy removal.
    435   _linker_configs = [
    436     "//chromium/build/config/win:default_incremental_linking",
    437 
    438     # Default to console-mode apps. Most of our targets are tests and such
    439     # that shouldn't use the windows subsystem.
    440     "//chromium/build/config/win:console",
    441   ]
    442 } else if (is_apple) {
    443   _linker_configs = [ "//chromium/build/config/apple:strip_all" ]
    444 } else {
    445   _linker_configs = []
    446 }
    447 
    448 # Executable defaults.
    449 default_executable_configs = default_compiler_configs + [
    450                                "//chromium/build/config/compiler:export_dynamic",
    451                                "//chromium/build/config:default_libs",
    452                                "//chromium/build/config:executable_config",
    453                              ] + _linker_configs
    454 
    455 if (is_win) {
    456   # Turn on linker CFI for executables, and position it so it can be removed
    457   # if needed.
    458   default_executable_configs += [ "//chromium/build/config/win:cfi_linker" ]
    459 }
    460 if (is_fuchsia) {
    461   # Sometimes executables are linked by rustc passing a command line to
    462   # clang++. It includes "-pie" which is pointless on Fuchsia. Suppress the
    463   # resulting (fatal) warning. Unfortunately there's no way to do this only
    464   # for binaries linked by rustc; gn does not make the distinction.
    465   default_executable_configs +=
    466       [ "//chromium/build/config/fuchsia:rustc_no_pie_warning" ]
    467 }
    468 
    469 set_defaults("executable") {
    470   configs = default_executable_configs
    471 }
    472 
    473 # Shared library and loadable module defaults (also for components in component
    474 # mode).
    475 default_shared_library_configs = default_compiler_configs + [
    476                                    "//chromium/build/config:default_libs",
    477                                    "//chromium/build/config:shared_library_config",
    478                                  ] + _linker_configs
    479 if (is_win) {
    480   # Turn on linker CFI for DLLs, and position it so it can be removed if needed.
    481   default_shared_library_configs += [ "//chromium/build/config/win:cfi_linker" ]
    482 }
    483 
    484 if (is_android) {
    485   # Strip native JNI exports from shared libraries by default. Binaries that
    486   # want this can remove this config.
    487   default_shared_library_configs +=
    488       [ "//chromium/build/config/android:hide_all_but_jni_onload" ]
    489 }
    490 if (is_fuchsia) {
    491   # Sometimes shared libraries are linked by rustc passing a command line to
    492   # clang++. It includes "-pie" which is pointless on Fuchsia. Suppress the
    493   # resulting (fatal) warning. Unfortunately there's no way to do this only
    494   # for binaries linked by rustc; gn does not make the distinction.
    495   default_shared_library_configs +=
    496       [ "//chromium/build/config/fuchsia:rustc_no_pie_warning" ]
    497 }
    498 set_defaults("shared_library") {
    499   configs = default_shared_library_configs
    500 }
    501 set_defaults("loadable_module") {
    502   configs = default_shared_library_configs
    503 
    504   # loadable_modules are generally used by other libs, not just via JNI.
    505   if (is_android) {
    506     configs -= [ "//chromium/build/config/android:hide_all_but_jni_onload" ]
    507   }
    508 }
    509 
    510 default_rust_proc_macro_configs =
    511     default_shared_library_configs + [ "//chromium/build/rust:proc_macro_extern" ] +
    512     # Rust proc macros don't support (Thin)LTO, so always remove it.
    513     [
    514       "//chromium/build/config/compiler:thinlto_optimize_default",
    515       "//chromium/build/config/compiler:thinlto_optimize_max",
    516     ] -
    517     [
    518       "//chromium/build/config/compiler:thinlto_optimize_default",
    519       "//chromium/build/config/compiler:thinlto_optimize_max",
    520     ]
    521 
    522 set_defaults("rust_proc_macro") {
    523   configs = default_rust_proc_macro_configs
    524 }
    525 
    526 # A helper for forwarding testonly and visibility.
    527 # Forwarding "*" does not include variables from outer scopes (to avoid copying
    528 # all globals into each template invocation), so it will not pick up
    529 # file-scoped or outer-template-scoped variables. Normally this behavior is
    530 # desired, but "visibility" and "testonly" are commonly defined in outer scopes.
    531 # Explicitly forwarding them in forward_variables_from() works around this
    532 # nuance. See //build/docs/writing_gn_templates.md#using-forward_variables_from
    533 TESTONLY_AND_VISIBILITY = [
    534   "testonly",
    535   "visibility",
    536 ]
    537 
    538 # Sets default dependencies for static_library and source_set targets.
    539 #
    540 # Variables
    541 #   use_libcxx_modules: If true, libc++'s modules are added to deps.
    542 #       This is true by default.
    543 foreach(_target_type,
    544         [
    545           "source_set",
    546           "static_library",
    547         ]) {
    548   template(_target_type) {
    549     target(_target_type, target_name) {
    550       forward_variables_from(invoker,
    551                              "*",
    552                              TESTONLY_AND_VISIBILITY + [ "use_libcxx_modules" ])
    553       forward_variables_from(invoker, TESTONLY_AND_VISIBILITY)
    554       if (!defined(inputs)) {
    555         inputs = []
    556       }
    557       if (!defined(deps)) {
    558         deps = []
    559       }
    560 
    561       if (false) { # Mozilla
    562       if (is_clang && (!defined(invoker.use_libcxx_modules) ||
    563                        invoker.use_libcxx_modules)) {
    564         # This is necessary for Clang modules builds.
    565         deps += [
    566           "//buildtools/third_party/libc++:std",
    567           "//buildtools/third_party/libc++:std_config",
    568           "//buildtools/third_party/libc++:std_core",
    569           "//buildtools/third_party/libc++:std_ctype_h",
    570           "//buildtools/third_party/libc++:std_errno_h",
    571           "//buildtools/third_party/libc++:std_fenv_h",
    572           "//buildtools/third_party/libc++:std_float_h",
    573           "//buildtools/third_party/libc++:std_inttypes_h",
    574           "//buildtools/third_party/libc++:std_math_h",
    575           "//buildtools/third_party/libc++:std_private_mbstate_t",
    576           "//buildtools/third_party/libc++:std_string_h",
    577           "//buildtools/third_party/libc++:std_uchar_h",
    578           "//buildtools/third_party/libc++:std_wctype_h",
    579         ]
    580       }
    581       }
    582 
    583       # Consumed by the unsafe-buffers plugin during compile.
    584       #
    585       # TODO(crbug.com/326584510): Reclient doesn't respect this variable, see
    586       # rbe_bug_326584510_missing_inputs in //build/config/clang/clang.gni
    587       _uses_cflags = false
    588       if (defined(sources)) {
    589         foreach(f, sources) {
    590           if (string_replace(f + ".END", ".cc.END", "") != f + ".END" ||
    591               string_replace(f + ".END", ".c.END", "") != f + ".END" ||
    592               string_replace(f + ".END", ".mm.END", "") != f + ".END" ||
    593               string_replace(f + ".END", ".m.END", "") != f + ".END") {
    594             _uses_cflags = true
    595           }
    596         }
    597       }
    598       if (_uses_cflags && clang_unsafe_buffers_paths != "") {
    599         inputs += [ clang_unsafe_buffers_paths ]
    600       }
    601     }
    602   }
    603 }
    604 
    605 # Sets default dependencies for executable and shared_library targets.
    606 #
    607 # Variables
    608 #   no_default_deps: If true, no standard dependencies will be added.
    609 #       Targets that set this usually also want to remove
    610 #       "//chromium/build/config/compiler:runtime_library" from configs (to remove
    611 #       its subconfig "//chromium/build/config/c++:runtime_library").
    612 #   use_libcxx_modules: If true, libc++'s modules are added to deps.
    613 #       This is true by default.
    614 foreach(_target_type,
    615         [
    616           "executable",
    617           "loadable_module",
    618           "shared_library",
    619         ]) {
    620   template(_target_type) {
    621     # Alias "target_name" because it is clobbered by forward_variables_from().
    622     _target_name = target_name
    623     target(_target_type, _target_name) {
    624       forward_variables_from(invoker,
    625                              "*",
    626                              TESTONLY_AND_VISIBILITY + [
    627                                    "no_default_deps",
    628                                    "use_libcxx_modules",
    629                                  ])
    630       forward_variables_from(invoker, TESTONLY_AND_VISIBILITY)
    631       if (!defined(inputs)) {
    632         inputs = []
    633       }
    634 
    635       # Consumed by the unsafe-buffers plugin during compile.
    636       #
    637       # TODO(crbug.com/326584510): Reclient doesn't respect this variable, see
    638       # rbe_bug_326584510_missing_inputs in //build/config/clang/clang.gni
    639       _uses_cflags = false
    640       if (defined(sources)) {
    641         foreach(f, sources) {
    642           if (string_replace(f + ".END", ".cc.END", "") != f + ".END" ||
    643               string_replace(f + ".END", ".c.END", "") != f + ".END" ||
    644               string_replace(f + ".END", ".mm.END", "") != f + ".END" ||
    645               string_replace(f + ".END", ".m.END", "") != f + ".END") {
    646             _uses_cflags = true
    647           }
    648         }
    649       }
    650       if (_uses_cflags && clang_unsafe_buffers_paths != "") {
    651         inputs += [ clang_unsafe_buffers_paths ]
    652       }
    653 
    654       if (!defined(deps)) {
    655         deps = []
    656       }
    657       if (false) { # Mozilla
    658       if (!defined(invoker.no_default_deps) || !invoker.no_default_deps) {
    659         # This pulls in one of:
    660         # //build/config:executable_deps
    661         # //build/config:loadable_module_deps
    662         # //build/config:shared_library_deps
    663         # (This explicit list is so that grepping for these configs finds where
    664         # they are used.)
    665         deps += [ "//chromium/build/config:${_target_type}_deps" ]
    666       }
    667 
    668       if (is_clang && (!defined(invoker.use_libcxx_modules) ||
    669                        invoker.use_libcxx_modules)) {
    670         # These are necessary for Clang modules builds.
    671         deps += [
    672           "//buildtools/third_party/libc++:_Builtin_limits",
    673           "//buildtools/third_party/libc++:_Builtin_stdarg",
    674           "//buildtools/third_party/libc++:_Builtin_stddef",
    675           "//buildtools/third_party/libc++:std",
    676           "//buildtools/third_party/libc++:std_config",
    677           "//buildtools/third_party/libc++:std_core",
    678           "//buildtools/third_party/libc++:std_ctype_h",
    679           "//buildtools/third_party/libc++:std_errno_h",
    680           "//buildtools/third_party/libc++:std_fenv_h",
    681           "//buildtools/third_party/libc++:std_float_h",
    682           "//buildtools/third_party/libc++:std_inttypes_h",
    683           "//buildtools/third_party/libc++:std_math_h",
    684           "//buildtools/third_party/libc++:std_private_mbstate_t",
    685           "//buildtools/third_party/libc++:std_string_h",
    686           "//buildtools/third_party/libc++:std_uchar_h",
    687           "//buildtools/third_party/libc++:std_wctype_h",
    688         ]
    689       }
    690       }
    691 
    692       # On Android, write shared library output file to metadata. We will use
    693       # this information to, for instance, collect all shared libraries that
    694       # should be packaged into an APK.
    695       if (!defined(invoker.metadata) && (is_android || is_robolectric) &&
    696           (_target_type == "shared_library" ||
    697            _target_type == "loadable_module")) {
    698         _output_name = _target_name
    699         if (defined(invoker.output_name)) {
    700           _output_name = invoker.output_name
    701         }
    702 
    703         # Remove 'lib' prefix from output name if it exists.
    704         _magic_prefix = "$0x01$0x01"
    705         _output_name = string_replace("${_magic_prefix}${_output_name}",
    706                                       "${_magic_prefix}lib",
    707                                       _magic_prefix,
    708                                       1)
    709         _output_name = string_replace(_output_name, _magic_prefix, "", 1)
    710 
    711         if (defined(output_extension)) {
    712           _shlib_extension = ".$output_extension"
    713         } else {
    714           _shlib_extension = ".so"
    715         }
    716 
    717         metadata = {
    718           shared_libraries =
    719               [ "$root_out_dir/lib${_output_name}${_shlib_extension}" ]
    720         }
    721       }
    722     }
    723   }
    724 }
    725 
    726 # ==============================================================================
    727 # COMPONENT SETUP
    728 # ==============================================================================
    729 
    730 # Defines a component, which equates to a shared_library when
    731 # is_component_build == true and a static_library otherwise.
    732 #
    733 # Use static libraries for the static build rather than source sets because
    734 # many of of our test binaries link many large dependencies but often don't
    735 # use large portions of them. The static libraries are much more efficient to
    736 # link in this situation since only the necessary object files are linked.
    737 #
    738 # The invoker can override the type of the target in the non-component-build
    739 # case by setting static_component_type to either "source_set" or
    740 # "static_library". If unset, the default will be used.
    741 template("component") {
    742   if (is_component_build) {
    743     _component_mode = "shared_library"
    744 
    745     # Generate a unique output_name for a shared library if not set by invoker.
    746     if (!defined(invoker.output_name)) {
    747       _output_name = get_label_info(":$target_name", "label_no_toolchain")
    748       _output_name =
    749           string_replace(_output_name, "$target_name:$target_name", target_name)
    750       _output_name = string_replace(_output_name, "//", "")
    751       _output_name = string_replace(_output_name, "/", "_")
    752       _output_name = string_replace(_output_name, ":", "_")
    753     }
    754   } else if (defined(invoker.static_component_type)) {
    755     assert(invoker.static_component_type == "static_library" ||
    756            invoker.static_component_type == "source_set")
    757     _component_mode = invoker.static_component_type
    758   } else if (!defined(invoker.sources) || invoker.sources == []) {
    759     # When there are no sources defined, use a source set to avoid creating
    760     # an empty static library (which generally don't work).
    761     _component_mode = "source_set"
    762   } else {
    763     _component_mode = "static_library"
    764   }
    765   target(_component_mode, target_name) {
    766     if (defined(_output_name)) {
    767       output_name = _output_name
    768     }
    769     if (is_component_build && is_android) {
    770       # By appending .cr, we prevent name collisions with libraries already
    771       # loaded by the Android zygote.
    772       output_extension = "cr.so"
    773     }
    774     forward_variables_from(invoker, TESTONLY_AND_VISIBILITY)
    775     forward_variables_from(invoker, "*", TESTONLY_AND_VISIBILITY)
    776   }
    777 }
    778 
    779 # Component defaults
    780 # Set a variable since we also want to make this available
    781 # to mixed_component.gni
    782 if (is_component_build) {
    783   default_component_configs = default_shared_library_configs
    784   if (is_android) {
    785     default_component_configs -=
    786         [ "//chromium/build/config/android:hide_all_but_jni_onload" ]
    787   }
    788   if (is_win) {
    789     # We don't want component dlls to statically load OS dlls that aren't
    790     # loaded normally.
    791     default_component_configs += [ "//chromium/build/config/win:delayloads" ]
    792   }
    793 } else {
    794   default_component_configs = default_compiler_configs
    795 }
    796 
    797 set_defaults("component") {
    798   configs = default_component_configs
    799 }