| # 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. |
| |
| # ============================================================================= |
| # WHAT IS THIS FILE? |
| # ============================================================================= |
| # |
| # This is the master GN build configuration. This file is loaded after the |
| # build args (args.gn) for the build directory and after the toplevel ".gn" |
| # file (which points to this file as the build configuration). |
| # |
| # This file will be executed and the resulting context will be used to execute |
| # every other file in the build. So variables declared here (that don't start |
| # with an underscore) will be implicitly global. |
| |
| # ============================================================================= |
| # 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 your feature is a single target, say //components/foo, you can put |
| # a declare_args() block in //components/foo/BUILD.gn and use it there. |
| # Nobody else in the build needs to see the flag. |
| # |
| # - Defines based on build variables should be implemented via the generated |
| # build flag header system. See //build/buildflag_header.gni. You can put |
| # the buildflag_header target in the same file as the build flag itself. You |
| # should almost never set "defines" directly. |
| # |
| # - If your flag toggles a target on and off or toggles between different |
| # versions of similar things, write a "group" target that forwards to the |
| # right target (or no target) depending on the value of the build flag. This |
| # group can be in the same BUILD.gn file as the build flag, and targets can |
| # depend unconditionally on the group rather than duplicating flag checks |
| # across many targets. |
| # |
| # - If a semi-random set of build files REALLY needs to know about a define and |
| # the above pattern for isolating the build logic in a forwarding group |
| # doesn't work, you can put the argument in a .gni file. This should be put |
| # in the lowest level of the build that knows about this feature (which should |
| # almost always be outside of the //build directory!). |
| # |
| # Other flag 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() { |
| # Set to enable the official build level of optimization. This has nothing |
| # to do with branding, but enables an additional level of optimization above |
| # release (!is_debug). This might be better expressed as a tri-state |
| # (debug, release, official) but for historical reasons there are two |
| # separate flags. |
| is_official_build = false |
| |
| # Whether we're a traditional desktop unix. |
| is_desktop_linux = current_os == "linux" |
| |
| # Set to true when compiling with the Clang compiler. |
| is_clang = current_os != "linux" || |
| (current_cpu != "s390x" && current_cpu != "s390" && |
| current_cpu != "ppc64" && current_cpu != "ppc" && |
| current_cpu != "mips" && current_cpu != "mips64") |
| |
| # 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. |
| } |
| |
| declare_args() { |
| # Debug build. Enabling official builds automatically sets is_debug to false. |
| is_debug = !is_official_build |
| } |
| |
| declare_args() { |
| # Component build. Setting to true compiles targets declared as "components" |
| # as shared libraries loaded dynamically. This speeds up development time. |
| # When false, components will be linked statically. |
| # |
| # For more information see |
| # https://chromium.googlesource.com/chromium/src/+/master/docs/component_build.md |
| is_component_build = is_debug && current_os != "ios" |
| } |
| |
| assert(!(is_debug && is_official_build), "Can't do official debug builds") |
| |
| # ============================================================================== |
| # 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") { |
| 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") { |
| # On Windows always use the target CPU for host builds for x86/x64. On the |
| # configurations we support this will always work and it saves build steps. |
| # Windows ARM64 targets require an x64 host for cross build. |
| if (target_cpu == "x86" || target_cpu == "x64") { |
| if (is_clang) { |
| host_toolchain = "//build/toolchain/win:win_clang_$target_cpu" |
| } else { |
| host_toolchain = "//build/toolchain/win:$target_cpu" |
| } |
| } else if (is_clang) { |
| host_toolchain = "//build/toolchain/win:win_clang_$host_cpu" |
| } else { |
| host_toolchain = "//build/toolchain/win:$host_cpu" |
| } |
| } else if (host_os == "aix") { |
| host_toolchain = "//build/toolchain/aix:$host_cpu" |
| } else { |
| assert(false, "Unsupported host_os: $host_os") |
| } |
| } |
| |
| _default_toolchain = "" |
| |
| if (target_os == "android") { |
| assert(host_os == "linux" || host_os == "mac", |
| "Android builds are only supported on Linux and Mac hosts.") |
| _default_toolchain = "//build/toolchain/android:android_clang_$target_cpu" |
| } else if (target_os == "chromeos" || target_os == "linux") { |
| # See comments in build/toolchain/cros/BUILD.gn about board compiles. |
| if (is_clang) { |
| _default_toolchain = "//build/toolchain/linux:clang_$target_cpu" |
| } else { |
| _default_toolchain = "//build/toolchain/linux:$target_cpu" |
| } |
| } else if (target_os == "fuchsia") { |
| _default_toolchain = "//build/toolchain/fuchsia:$target_cpu" |
| } else if (target_os == "ios") { |
| _default_toolchain = "//build/toolchain/mac:ios_clang_$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. |
| # Beware, win cross builds have some caveats, see docs/win_cross.md |
| if (is_clang) { |
| _default_toolchain = "//build/toolchain/win:win_clang_$target_cpu" |
| } else { |
| _default_toolchain = "//build/toolchain/win:$target_cpu" |
| } |
| } else if (target_os == "winuwp") { |
| # Only target WinUWP on for a Windows store application and only |
| # x86, x64 and arm are supported target CPUs. |
| assert(target_cpu == "x86" || target_cpu == "x64" || target_cpu == "arm" || |
| target_cpu == "arm64") |
| _default_toolchain = "//build/toolchain/win:uwp_$target_cpu" |
| } else if (target_os == "aix") { |
| _default_toolchain = "//build/toolchain/aix:$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. |
| |
| is_android = current_os == "android" |
| is_chromeos = current_os == "chromeos" |
| is_fuchsia = current_os == "fuchsia" |
| is_ios = current_os == "ios" |
| is_linux = current_os == "chromeos" || current_os == "linux" |
| is_mac = current_os == "mac" |
| is_nacl = current_os == "nacl" |
| is_win = current_os == "win" || current_os == "winuwp" |
| |
| is_posix = !is_win && !is_fuchsia |
| |
| # ============================================================================= |
| # 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 |
| # automatically 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 |
| # must 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_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. |
| # |
| # WHAT GOES HERE? |
| # |
| # Other than the main compiler and linker configs, the only reason for a config |
| # to be in this list is if some targets need to explicitly override that config |
| # by removing it. This is how targets opt-out of flags. If you don't have that |
| # requirement and just need to add a config everywhere, reference it as a |
| # sub-config of an existing one, most commonly the main "compiler" one. |
| |
| # Holds all configs used for running the compiler. |
| default_compiler_configs = [ |
| "//build/config:feature_flags", |
| "//build/config/compiler:afdo", |
| "//build/config/compiler:afdo_optimize_size", |
| "//build/config/compiler:assembler_debug_dir", |
| "//build/config/compiler:compiler", |
| "//build/config/compiler:compiler_arm_fpu", |
| "//build/config/compiler:compiler_arm_thumb", |
| "//build/config/compiler:chromium_code", |
| "//build/config/compiler:default_include_dirs", |
| "//build/config/compiler:default_optimization", |
| "//build/config/compiler:default_stack_frames", |
| "//build/config/compiler:default_symbols", |
| "//build/config/compiler:export_dynamic", |
| "//build/config/compiler:no_exceptions", |
| "//build/config/compiler:no_rtti", |
| "//build/config/compiler:runtime_library", |
| "//build/config/compiler:thin_archive", |
| "//build/config/coverage:default_coverage", |
| "//build/config/sanitizers:default_sanitizer_flags", |
| ] |
| |
| if (is_win) { |
| default_compiler_configs += [ |
| "//build/config/win:default_crt", |
| "//build/config/win:lean_and_mean", |
| "//build/config/win:nominmax", |
| "//build/config/win:unicode", |
| "//build/config/win:winver", |
| ] |
| } |
| |
| if (is_posix) { |
| if (current_os != "aix") { |
| default_compiler_configs += |
| [ "//build/config/gcc:symbol_visibility_hidden" ] |
| } |
| } |
| |
| if (is_fuchsia) { |
| default_compiler_configs += [ "//build/config/gcc:symbol_visibility_hidden" ] |
| } |
| |
| if (is_android) { |
| default_compiler_configs += |
| [ "//build/config/android:default_orderfile_instrumentation" ] |
| } |
| |
| if (is_win) { |
| default_compiler_configs += |
| [ "//build/config/win:default_cygprofile_instrumentation" ] |
| } |
| |
| if (is_clang && !is_nacl) { |
| default_compiler_configs += [ |
| "//build/config/clang:find_bad_constructs", |
| "//build/config/clang:extra_warnings", |
| ] |
| } |
| |
| # Debug/release-related defines. |
| if (is_debug) { |
| default_compiler_configs += [ "//build/config:debug" ] |
| } else { |
| default_compiler_configs += [ "//build/config:release" ] |
| } |
| |
| # Static libraries and source sets use only the compiler ones. |
| set_defaults("static_library") { |
| configs = default_compiler_configs |
| } |
| set_defaults("source_set") { |
| configs = default_compiler_configs |
| } |
| |
| # Compute the set of configs common to all linked targets (shared libraries, |
| # loadable modules, executables) to avoid duplication below. |
| if (is_win) { |
| # Many targets remove these configs, so they are not contained within |
| # //build/config:executable_config for easy removal. |
| _linker_configs = [ |
| "//build/config/win:default_incremental_linking", |
| |
| # Default to console-mode apps. Most of our targets are tests and such |
| # that shouldn't use the windows subsystem. |
| "//build/config/win:console", |
| ] |
| } else if (is_mac) { |
| _linker_configs = [ "//build/config/mac:strip_all" ] |
| } else { |
| _linker_configs = [] |
| } |
| |
| # Executable defaults. |
| default_executable_configs = default_compiler_configs + [ |
| "//build/config:default_libs", |
| "//build/config:executable_config", |
| ] + _linker_configs |
| set_defaults("executable") { |
| configs = default_executable_configs |
| } |
| |
| # Shared library and loadable module defaults (also for components in component |
| # mode). |
| default_shared_library_configs = default_compiler_configs + [ |
| "//build/config:default_libs", |
| "//build/config:shared_library_config", |
| ] + _linker_configs |
| if (is_android) { |
| # Strip native JNI exports from shared libraries by default. Binaries that |
| # want this can remove this config. |
| default_shared_library_configs += |
| [ "//build/config/android:hide_all_but_jni_onload" ] |
| } |
| set_defaults("shared_library") { |
| configs = default_shared_library_configs |
| } |
| set_defaults("loadable_module") { |
| configs = default_shared_library_configs |
| |
| # loadable_modules are generally used by other libs, not just via JNI. |
| if (is_android) { |
| configs -= [ "//build/config/android:hide_all_but_jni_onload" ] |
| } |
| } |
| |
| # Sets default dependencies for executable and shared_library targets. |
| # |
| # Variables |
| # no_default_deps: If true, no standard dependencies will be added. |
| foreach(_target_type, |
| [ |
| "executable", |
| "loadable_module", |
| "shared_library", |
| ]) { |
| template(_target_type) { |
| target(_target_type, target_name) { |
| forward_variables_from(invoker, "*", [ "no_default_deps" ]) |
| if (!defined(deps)) { |
| deps = [] |
| } |
| if (!defined(invoker.no_default_deps) || !invoker.no_default_deps) { |
| deps += [ "//build/config:${_target_type}_deps" ] |
| } |
| } |
| } |
| } |
| |
| # ============================================================================== |
| # COMPONENT SETUP |
| # ============================================================================== |
| |
| # Defines a component, which equates to a shared_library when |
| # is_component_build == true and a static_library otherwise. |
| # |
| # Use static libraries for the static build rather than source sets because |
| # many of of our test binaries link many large dependencies but often don't |
| # use large portions of them. The static libraries are much more efficient to |
| # link in this situation since only the necessary object files are linked. |
| # |
| # The invoker can override the type of the target in the non-component-build |
| # case by setting static_component_type to either "source_set" or |
| # "static_library". If unset, the default will be used. |
| template("component") { |
| if (is_component_build) { |
| _component_mode = "shared_library" |
| } else if (defined(invoker.static_component_type)) { |
| assert(invoker.static_component_type == "static_library" || |
| invoker.static_component_type == "source_set") |
| _component_mode = invoker.static_component_type |
| } else if (!defined(invoker.sources)) { |
| # When there are no sources defined, use a source set to avoid creating |
| # an empty static library (which generally don't work). |
| _component_mode = "source_set" |
| } else { |
| _component_mode = "static_library" |
| } |
| target(_component_mode, target_name) { |
| # Explicitly forward visibility, implicitly forward everything else. |
| # Forwarding "*" doesn't recurse into nested scopes (to avoid copying all |
| # globals into each template invocation), so won't pick up file-scoped |
| # variables. Normally this isn't too bad, but visibility is commonly |
| # defined at the file scope. Explicitly forwarding visibility and then |
| # excluding it from the "*" set works around this problem. |
| # See http://crbug.com/594610 |
| forward_variables_from(invoker, [ "visibility" ]) |
| forward_variables_from(invoker, "*", [ "visibility" ]) |
| } |
| } |
| |
| # Component defaults |
| set_defaults("component") { |
| if (is_component_build) { |
| configs = default_shared_library_configs |
| if (is_android) { |
| configs -= [ "//build/config/android:hide_all_but_jni_onload" ] |
| } |
| } else { |
| configs = default_compiler_configs |
| } |
| } |