| # 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. |
| |
| # ============================================================================= |
| # PLATFORM SELECTION |
| # ============================================================================= |
| # |
| # There are two main things to set: "os" and "cpu". The "toolchain" is the name |
| # of the GN thing that encodes combinations of these things. |
| # |
| # Users typically only set the variables "target_os" and "target_cpu" in "gn |
| # args", the rest are set up by our build and internal to GN. |
| # |
| # There are three different types of each of these things: The "host" |
| # represents the computer doing the compile and never changes. The "target" |
| # represents the main thing we're trying to build. The "current" represents |
| # which configuration is currently being defined, which can be either the |
| # host, the target, or something completely different (like nacl). GN will |
| # run the same build file multiple times for the different required |
| # configuration in the same build. |
| # |
| # This gives the following variables: |
| # - host_os, host_cpu, host_toolchain |
| # - target_os, target_cpu, default_toolchain |
| # - current_os, current_cpu, current_toolchain. |
| # |
| # Note the default_toolchain isn't symmetrical (you would expect |
| # target_toolchain). This is because the "default" toolchain is a GN built-in |
| # concept, and "target" is something our build sets up that's symmetrical with |
| # its GYP counterpart. Potentially the built-in default_toolchain variable |
| # could be renamed in the future. |
| # |
| # When writing build files, to do something only for the host: |
| # if (current_toolchain == host_toolchain) { ... |
| |
| if (target_os == "") { |
| target_os = host_os |
| } |
| |
| if (target_cpu == "") { |
| if (target_os == "android") { |
| # If we're building for Android, we should assume that we want to |
| # build for ARM by default, not the host_cpu (which is likely x64). |
| # This allows us to not have to specify both target_os and target_cpu |
| # on the command line. |
| target_cpu = "arm" |
| } else { |
| target_cpu = host_cpu |
| } |
| } |
| |
| if (current_cpu == "") { |
| current_cpu = target_cpu |
| } |
| if (current_os == "") { |
| current_os = target_os |
| } |
| |
| # ============================================================================= |
| # BUILD FLAGS |
| # ============================================================================= |
| # |
| # This block lists input arguments to the build, along with their default |
| # values. |
| # |
| # If a value is specified on the command line, it will overwrite the defaults |
| # given in a declare_args block, otherwise the default will be used. |
| # |
| # YOU SHOULD ALMOST NEVER NEED TO ADD FLAGS TO THIS FILE. GN allows any file in |
| # the build to declare build flags. If you need a flag for a single component, |
| # you can just declare it in the corresponding BUILD.gn file. If you need a |
| # flag in multiple components, there are a few options: |
| # |
| # - If your feature is a single target, say //components/foo, and the targets |
| # depending on foo need to have some define set if foo is enabled: (1) Write |
| # a declare_args block in foo's BUILD.gn file listing your enable_foo build |
| # flag. (2) Write a config in that file listing the define, and list that |
| # config in foo's public_configs. This will propagate that define to all the |
| # targets depending on foo. (3) When foo is not enabled, just make it expand |
| # to an empty group (or whatever's appropriate for the "off" state of your |
| # feature. |
| # |
| # - If a semi-random set of targets need to know about a define: (1) In the |
| # lowest level of the build that knows about this feature, add a declare_args |
| # block in the build file for your enable flag. (2) Write a config that adds |
| # a define conditionally based on that build flags. (3) Manually add that |
| # config to the "configs" applying to the targets that need the define. |
| # |
| # - If a semi-random set of targets need to know about the build flag (to do |
| # file inclusion or exclusion, more than just defines): (1) Write a .gni file |
| # in the lowest-level directory that knows about the feature. (2) Put the |
| # declare_args block with your build flag in that .gni file. (3) Import that |
| # .gni file from the BUILD.gn files that need the flag. |
| # |
| # Other advice: |
| # |
| # - Use boolean values when possible. If you need a default value that expands |
| # to some complex thing in the default case (like the location of the |
| # compiler which would be computed by a script), use a default value of -1 or |
| # the empty string. Outside of the declare_args block, conditionally expand |
| # the default value as necessary. |
| # |
| # - Use a name like "use_foo" or "is_foo" (whatever is more appropriate for |
| # your feature) rather than just "foo". |
| # |
| # - Write good comments directly above the declaration with no blank line. |
| # These comments will appear as documentation in "gn args --list". |
| # |
| # - Don't call exec_script inside declare_args. This will execute the script |
| # even if the value is overridden, which is wasteful. See first bullet. |
| |
| declare_args() { |
| # Component build. |
| is_component_build = false |
| |
| # Debug build. |
| is_debug = true |
| |
| # Whether we're a traditional desktop unix. |
| is_desktop_linux = current_os == "linux" |
| |
| # Set to true when compiling with the Clang compiler. Typically this is used |
| # to configure warnings. |
| is_clang = current_os == "mac" || current_os == "ios" || |
| current_os == "linux" || current_os == "chromeos" |
| |
| # Allows the path to a custom target toolchain to be injected as a single |
| # argument, and set as the default toolchain. |
| custom_toolchain = "" |
| |
| # This should not normally be set as a build argument. It's here so that |
| # every toolchain can pass through the "global" value via toolchain_args(). |
| host_toolchain = "" |
| |
| # DON'T ADD MORE FLAGS HERE. Read the comment above. |
| } |
| |
| # ============================================================================== |
| # TOOLCHAIN SETUP |
| # ============================================================================== |
| # |
| # Here we set the default toolchain, as well as the variable host_toolchain |
| # which will identify the toolchain corresponding to the local system when |
| # doing cross-compiles. When not cross-compiling, this will be the same as the |
| # default toolchain. |
| # |
| # We do this before anything else to make sure we complain about any |
| # unsupported os/cpu combinations as early as possible. |
| |
| if (host_toolchain == "") { |
| # This should only happen in the top-level context. |
| # In a specific toolchain context, the toolchain_args() |
| # block should have propagated a value down. |
| # TODO(dpranke): Add some sort of assert here that verifies that |
| # no toolchain omitted host_toolchain from its toolchain_args(). |
| |
| if (host_os == "linux") { |
| if (target_os != "linux") { |
| # TODO(dpranke) - is_clang normally applies only to the target |
| # build, and there is no way to indicate that you want to override |
| # it for both the target build *and* the host build. Do we need to |
| # support this? |
| host_toolchain = "//build/toolchain/linux:clang_$host_cpu" |
| } else if (is_clang) { |
| host_toolchain = "//build/toolchain/linux:clang_$host_cpu" |
| } else { |
| host_toolchain = "//build/toolchain/linux:$host_cpu" |
| } |
| } else if (host_os == "mac") { |
| host_toolchain = "//build/toolchain/mac:clang_$host_cpu" |
| } else if (host_os == "win") { |
| # TODO(crbug.com/467159): win cross-compiles don't actually work yet, so |
| # use the target_cpu instead of the host_cpu. |
| if (is_clang) { |
| host_toolchain = "//build/toolchain/win:clang_$target_cpu" |
| } else { |
| host_toolchain = "//build/toolchain/win:$target_cpu" |
| } |
| } else { |
| assert(false, "Unsupported host_os: $host_os") |
| } |
| } |
| |
| _default_toolchain = "" |
| |
| if (target_os == "android") { |
| assert(host_os == "linux" || host_os == "mac", |
| "Android builds are only supported on Linux and Mac hosts.") |
| if (is_clang) { |
| _default_toolchain = "//build/toolchain/android:clang_$target_cpu" |
| } else { |
| _default_toolchain = "//build/toolchain/android:$target_cpu" |
| } |
| } else if (target_os == "chromeos") { |
| assert(host_os == "linux", |
| "ChromeOS builds are only supported on Linux hosts.") |
| if (is_clang) { |
| _default_toolchain = "//build/toolchain/linux:clang_$target_cpu" |
| } else { |
| _default_toolchain = "//build/toolchain/linux:$target_cpu" |
| } |
| } else if (target_os == "ios") { |
| _default_toolchain = "//build/toolchain/mac:ios_clang_arm" |
| } else if (target_os == "linux") { |
| if (is_clang) { |
| _default_toolchain = "//build/toolchain/linux:clang_$target_cpu" |
| } else { |
| _default_toolchain = "//build/toolchain/linux:$target_cpu" |
| } |
| } else if (target_os == "mac") { |
| assert(host_os == "mac", "Mac cross-compiles are unsupported.") |
| _default_toolchain = host_toolchain |
| } else if (target_os == "win") { |
| # On Windows we use the same toolchain for host and target by default. |
| assert(target_os == host_os, "Win cross-compiles only work on win hosts.") |
| if (is_clang) { |
| _default_toolchain = "//build/toolchain/win:clang_$target_cpu" |
| } else { |
| _default_toolchain = "//build/toolchain/win:$target_cpu" |
| } |
| } else if (target_os == "winrt_81" || target_os == "winrt_81_phone" || |
| target_os == "winrt_10") { |
| _default_toolchain = "//build/toolchain/win:winrt_$target_cpu" |
| } else { |
| assert(false, "Unsupported target_os: $target_os") |
| } |
| |
| # If a custom toolchain has been set in the args, set it as default. Otherwise, |
| # set the default toolchain for the platform (if any). |
| if (custom_toolchain != "") { |
| set_default_toolchain(custom_toolchain) |
| } else if (_default_toolchain != "") { |
| set_default_toolchain(_default_toolchain) |
| } |
| |
| # ============================================================================= |
| # OS DEFINITIONS |
| # ============================================================================= |
| # |
| # We set these various is_FOO booleans for convenience in writing OS-based |
| # conditions. |
| # |
| # - is_android, is_chromeos, is_ios, and is_win should be obvious. |
| # - is_mac is set only for desktop Mac. It is not set on iOS. |
| # - is_posix is true for mac and any Unix-like system (basically everything |
| # except Windows). |
| # - is_linux is true for desktop Linux and ChromeOS, but not Android (which is |
| # generally too different despite being based on the Linux kernel). |
| # |
| # Do not add more is_* variants here for random lesser-used Unix systems like |
| # aix or one of the BSDs. If you need to check these, just check the |
| # current_os value directly. |
| |
| if (current_os == "win" || current_os == "winrt_81" || |
| current_os == "winrt_81_phone" || current_os == "winrt_10") { |
| is_android = false |
| is_chromeos = false |
| is_ios = false |
| is_linux = false |
| is_mac = false |
| is_nacl = false |
| is_posix = false |
| is_win = true |
| } else if (current_os == "mac") { |
| is_android = false |
| is_chromeos = false |
| is_ios = false |
| is_linux = false |
| is_mac = true |
| is_nacl = false |
| is_posix = true |
| is_win = false |
| } else if (current_os == "android") { |
| is_android = true |
| is_chromeos = false |
| is_ios = false |
| is_linux = false |
| is_mac = false |
| is_nacl = false |
| is_posix = true |
| is_win = false |
| } else if (current_os == "chromeos") { |
| is_android = false |
| is_chromeos = true |
| is_ios = false |
| is_linux = true |
| is_mac = false |
| is_nacl = false |
| is_posix = true |
| is_win = false |
| } else if (current_os == "nacl") { |
| # current_os == "nacl" will be passed by the nacl toolchain definition. |
| # It is not set by default or on the command line. We treat is as a |
| # Posix variant. |
| is_android = false |
| is_chromeos = false |
| is_ios = false |
| is_linux = false |
| is_mac = false |
| is_nacl = true |
| is_posix = true |
| is_win = false |
| } else if (current_os == "ios") { |
| is_android = false |
| is_chromeos = false |
| is_ios = true |
| is_linux = false |
| is_mac = false |
| is_nacl = false |
| is_posix = true |
| is_win = false |
| } else if (current_os == "linux") { |
| is_android = false |
| is_chromeos = false |
| is_ios = false |
| is_linux = true |
| is_mac = false |
| is_nacl = false |
| is_posix = true |
| is_win = false |
| } |
| |
| # ============================================================================= |
| # SOURCES FILTERS |
| # ============================================================================= |
| # |
| # These patterns filter out platform-specific files when assigning to the |
| # sources variable. The magic variable |sources_assignment_filter| is applied |
| # to each assignment or appending to the sources variable and matches are |
| # automatcally removed. |
| # |
| # Note that the patterns are NOT regular expressions. Only "*" and "\b" (path |
| # boundary = end of string or slash) are supported, and the entire string |
| # muct match the pattern (so you need "*.cc" to match all .cc files, for |
| # example). |
| |
| # DO NOT ADD MORE PATTERNS TO THIS LIST, see set_sources_assignment_filter call |
| # below. |
| sources_assignment_filter = [] |
| if (!is_posix) { |
| sources_assignment_filter += [ |
| "*_posix.h", |
| "*_posix.cc", |
| "*_posix_unittest.h", |
| "*_posix_unittest.cc", |
| "*\bposix/*", |
| ] |
| } |
| if (!is_win) { |
| sources_assignment_filter += [ |
| "*_win.cc", |
| "*_win.h", |
| "*_win_unittest.cc", |
| "*\bwin/*", |
| "*.def", |
| "*.rc", |
| ] |
| } |
| if (!is_mac) { |
| sources_assignment_filter += [ |
| "*_mac.h", |
| "*_mac.cc", |
| "*_mac.mm", |
| "*_mac_unittest.h", |
| "*_mac_unittest.cc", |
| "*_mac_unittest.mm", |
| "*\bmac/*", |
| "*_cocoa.h", |
| "*_cocoa.cc", |
| "*_cocoa.mm", |
| "*_cocoa_unittest.h", |
| "*_cocoa_unittest.cc", |
| "*_cocoa_unittest.mm", |
| "*\bcocoa/*", |
| ] |
| } |
| if (!is_ios) { |
| sources_assignment_filter += [ |
| "*_ios.h", |
| "*_ios.cc", |
| "*_ios.mm", |
| "*_ios_unittest.h", |
| "*_ios_unittest.cc", |
| "*_ios_unittest.mm", |
| "*\bios/*", |
| ] |
| } |
| if (!is_mac && !is_ios) { |
| sources_assignment_filter += [ "*.mm" ] |
| } |
| if (!is_linux) { |
| sources_assignment_filter += [ |
| "*_linux.h", |
| "*_linux.cc", |
| "*_linux_unittest.h", |
| "*_linux_unittest.cc", |
| "*\blinux/*", |
| ] |
| } |
| if (!is_android) { |
| sources_assignment_filter += [ |
| "*_android.h", |
| "*_android.cc", |
| "*_android_unittest.h", |
| "*_android_unittest.cc", |
| "*\bandroid/*", |
| ] |
| } |
| if (!is_chromeos) { |
| sources_assignment_filter += [ |
| "*_chromeos.h", |
| "*_chromeos.cc", |
| "*_chromeos_unittest.h", |
| "*_chromeos_unittest.cc", |
| "*\bchromeos/*", |
| ] |
| } |
| |
| # DO NOT ADD MORE PATTERNS TO THIS LIST, see set_sources_assignment_filter call |
| # below. |
| |
| # Actually save this list. |
| # |
| # These patterns are executed for every file in the source tree of every run. |
| # Therefore, adding more patterns slows down the build for everybody. We should |
| # only add automatic patterns for configurations affecting hundreds of files |
| # across many projects in the tree. |
| # |
| # Therefore, we only add rules to this list corresponding to platforms on the |
| # Chromium waterfall. This is not for non-officially-supported platforms |
| # (FreeBSD, etc.) toolkits, (X11, GTK, etc.), or features. For these cases, |
| # write a conditional in the target to remove the file(s) from the list when |
| # your platform/toolkit/feature doesn't apply. |
| set_sources_assignment_filter(sources_assignment_filter) |
| |
| # ============================================================================= |
| # TARGET DEFAULTS |
| # ============================================================================= |
| # |
| # Set up the default configuration for every build target of the given type. |
| # The values configured here will be automatically set on the scope of the |
| # corresponding target. Target definitions can add or remove to the settings |
| # here as needed. |
| |
| # Holds all configs used for making native executables and libraries, to avoid |
| # duplication in each target below. |
| _native_compiler_configs = [ |
| "//build/config:feature_flags", |
| "//build/config/compiler:compiler", |
| "//build/config/compiler:compiler_arm_fpu", |
| "//build/config/compiler:chromium_code", |
| "//build/config/compiler:default_include_dirs", |
| "//build/config/compiler:default_optimization", |
| "//build/config/compiler:default_symbols", |
| "//build/config/compiler:no_rtti", |
| "//build/config/compiler:runtime_library", |
| "//build/config/sanitizers:default_sanitizer_flags", |
| "//build/config/sanitizers:default_sanitizer_coverage_flags", |
| ] |
| if (is_win) { |
| _native_compiler_configs += [ |
| "//build/config/win:lean_and_mean", |
| "//build/config/win:nominmax", |
| "//build/config/win:unicode", |
| "//build/config/win:winver", |
| ] |
| } |
| if (current_os == "winrt_81" || current_os == "winrt_81_phone" || |
| current_os == "winrt_10") { |
| _native_compiler_configs += [ "//build/config/win:target_winrt" ] |
| } |
| if (is_posix) { |
| _native_compiler_configs += [ |
| "//build/config/gcc:no_exceptions", |
| "//build/config/gcc:symbol_visibility_hidden", |
| ] |
| } |
| |
| if (is_android) { |
| _native_compiler_configs += |
| [ "//build/config/android:default_cygprofile_instrumentation" ] |
| } |
| |
| if (is_clang && !is_nacl) { |
| _native_compiler_configs += [ |
| "//build/config/clang:find_bad_constructs", |
| "//build/config/clang:extra_warnings", |
| ] |
| } |
| |
| # Debug/release-related defines. |
| if (is_debug) { |
| _native_compiler_configs += [ "//build/config:debug" ] |
| } else { |
| _native_compiler_configs += [ "//build/config:release" ] |
| } |
| |
| # Windows linker setup for EXEs and DLLs. |
| if (is_win) { |
| _windows_linker_configs = [ |
| "//build/config/win:default_incremental_linking", |
| "//build/config/win:sdk_link", |
| "//build/config/win:common_linker_setup", |
| |
| # Default to console-mode apps. Most of our targets are tests and such |
| # that shouldn't use the windows subsystem. |
| "//build/config/win:console", |
| ] |
| } |
| |
| # Executable defaults. |
| _executable_configs = |
| _native_compiler_configs + [ "//build/config:default_libs" ] |
| if (is_win) { |
| _executable_configs += _windows_linker_configs |
| } else if (is_mac) { |
| _executable_configs += [ |
| "//build/config/mac:mac_dynamic_flags", |
| "//build/config/mac:mac_executable_flags", |
| ] |
| } else if (is_linux || is_android) { |
| _executable_configs += [ "//build/config/gcc:executable_ldconfig" ] |
| if (is_android) { |
| _executable_configs += [ "//build/config/android:executable_config" ] |
| } |
| } |
| set_defaults("executable") { |
| configs = _executable_configs |
| } |
| |
| # Static library defaults. |
| set_defaults("static_library") { |
| configs = _native_compiler_configs |
| } |
| |
| # Shared library and loadable module defaults (also for components in component |
| # mode). |
| _shared_library_configs = |
| _native_compiler_configs + [ "//build/config:default_libs" ] |
| if (is_win) { |
| _shared_library_configs += _windows_linker_configs |
| } else if (is_mac) { |
| _shared_library_configs += [ "//build/config/mac:mac_dynamic_flags" ] |
| } else if (is_android) { |
| # Strip native JNI exports from shared libraries by default. Binaries that |
| # want this can remove this config. |
| _shared_library_configs += |
| [ "//build/config/android:hide_native_jni_exports" ] |
| } |
| set_defaults("shared_library") { |
| configs = _shared_library_configs |
| } |
| set_defaults("loadable_module") { |
| configs = _shared_library_configs |
| } |
| if (is_component_build) { |
| set_defaults("component") { |
| configs = _shared_library_configs |
| } |
| } |
| |
| # Source set defaults (also for components in non-component mode). |
| set_defaults("source_set") { |
| configs = _native_compiler_configs |
| } |
| if (!is_component_build) { |
| set_defaults("component") { |
| configs = _native_compiler_configs |
| } |
| } |
| |
| # Test defaults. |
| set_defaults("test") { |
| if (is_android) { |
| configs = _shared_library_configs |
| } else { |
| configs = _executable_configs |
| } |
| } |
| |
| # ============================================================================== |
| # COMPONENT SETUP |
| # ============================================================================== |
| |
| if (is_component_build) { |
| _component_mode = "shared_library" |
| } else { |
| _component_mode = "source_set" |
| } |
| template("component") { |
| target(_component_mode, target_name) { |
| forward_variables_from(invoker, "*") |
| |
| # All shared libraries must have the sanitizer deps to properly link in |
| # asan mode (this target will be empty in other cases). |
| if (!defined(deps)) { |
| deps = [] |
| } |
| deps += [ "//build/config/sanitizers:deps" ] |
| } |
| } |