common-mk/BUILD.gn - chromiumos/platform2 - Git at Google

 # Copyright 2018 The ChromiumOS Authors
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.

 declare_args() {
   # Set this to false if you'd like to disable -Werror.
   enable_werror = true

   # Set this to false if you want to disable Large File Support (LFS).
   enable_lfs = true
 }

 if (use.pigweed) {
   # TODO(b/267537074) - This will fix this workaround.
   # Pigweed defaults to use CXX17 standard, update pw variable
   # to match platform2 CXX20 standard.
   dir_pigweed = "//third_party/pigweed"
   import("$dir_pigweed/pw_toolchain/traits.gni")
   pw_toolchain_CXX_STANDARD = pw_toolchain_STANDARD.CXX20
 }

 _cflags_no_exceptions = [
   "-fno-exceptions",
   "-fno-unwind-tables",
   "-fno-asynchronous-unwind-tables",
 ]

 config("no_exceptions") {
   cflags_cc = _cflags_no_exceptions
   cflags_c = _cflags_no_exceptions
 }

 _gcc_cflags = [ "-Wno-psabi" ]

 config("gcc_cflags_c") {
   cflags_c = _gcc_cflags
 }
 config("gcc_cflags_cc") {
   cflags_cc = _gcc_cflags
 }

 # Note: DO NOT USE THIS.  Use brillo/brillo_export.h instead to export symbols.
 #
 # Symbol visibility is set to be internal by default. Add this to your target's
 # configs to make its symbols visible.
 # Setting "-fvisibility=default" directly in your target's cflags doesn't work
 # because it will be overwritten by the "-fvisibility=internal" in the
 # compiler_defaults' cflags.
 config("visibility_default") {
   # gnlint: disable=GnLintVisibilityFlags
   cflags = [ "-fvisibility=default" ]
 }

 config("compiler_defaults") {
   defines = []
   libs = []

   include_dirs = [
     "${root_gen_dir}/include",
     "${platform2_root}",
   ]
   cflags = [
     "-Wall",
     "-Wunused",
     "-Wbool-operation",
     "-Wfree-nonheap-object",
     "-Wint-in-bool-context",
     "-Wstring-compare",
     "-Wstring-plus-int",
     "-Wxor-used-as-pow",
     "-Wdeprecated-declarations",

     # We use C99 array designators in C++ code.  Our compilers support this
     # extension since C++ has no equivalent yet (as of C++20).
     "-Wno-c99-designator",
     "-Wno-unused-parameter",
     "-Wunreachable-code",
     "-Wunreachable-code-return",
     "-ggdb3",
     "-fstack-protector-strong",
     "-Wformat=2",

     # When a class is exported through __attribute__((visibility("default"))),
     # we still want to eliminate symbols from inline class member functions to
     # reduce symbol resolution overhead. Therefore, pass
     # -fvisibility-inlines-hidden in addition to -fvisibility=internal.
     # (go/cros-symbol-slimming)
     "-fvisibility=internal",
     "-fvisibility-inlines-hidden",
     "-Wa,--noexecstack",
     "-Wimplicit-fallthrough",
   ]
   cflags_c = [ "-std=gnu17" ] + external_cppflags + external_cxxflags
   cc_version = "-std=gnu++20"

   cflags_cc = [ cc_version ] + external_cppflags + external_cxxflags
   ldflags = external_ldflags + [
               "-Wl,-z,relro",
               "-Wl,-z,noexecstack",
               "-Wl,-z,now",
               "-Wl,--as-needed",

               # Pass -Bsymbolic-non-weak which pre-binds symbols in the same
               # DSO to improve startup performance. We don't support
               # interposing non-weak symbols. (go/cros-symbol-slimming)
               "-Wl,-Bsymbolic-non-weak",
             ]
   if (link_stdcppfs) {
     libs += [ "stdc++fs" ]
   }
   if (enable_werror) {
     cflags += [
       "-Werror",

       # TODO(b/217226507): reduce the scope of this error suppression or
       # fix each case.
       "-Wno-error=deprecated-enum-enum-conversion",

       # TODO(b/217226507): some lambda capturing (specifically tests with
       # gmock) implicitly capture this, but in C++20 it should to be
       # explicit. However, this feature is not available until C++20, so
       # updating the code requires C++20 enabled.
       # For transition, suppress the error, and once C++20 is stabilized
       # we can clean up the cases.
       "-Wno-error=deprecated-this-capture",
     ]
   }

   if (use.cros_host) {
     defines += [ "NDEBUG" ]
   }
   if (use.cros_debug) {
     # Initialize stack variables with values that will likely transform
     # logic bugs into crashes.
     cflags += [ "-ftrivial-auto-var-init=pattern" ]
   }
   if (enable_lfs) {
     defines += [
       # Enable support for new LFS funcs (ftello/etc...).
       "_LARGEFILE_SOURCE",

       # Enable support for 64bit variants (off64_t/fseeko64/etc...).
       "_LARGEFILE64_SOURCE",

       # Default to 64bit variants (off_t is defined as off64_t).
       "_FILE_OFFSET_BITS=64",
     ]
   }

   # We only rely on `enable_exceptions` arg to control no_exceptions flags
   # (see BUILDCONFIG.gn) and ignore if the given external flags contain these
   # flags. As removing non-existing flags causes error on GN, we add them before
   # its removal to unconditionally remove them.
   cflags_cc += _cflags_no_exceptions
   cflags_c += _cflags_no_exceptions
   cflags_cc -= _cflags_no_exceptions
   cflags_c -= _cflags_no_exceptions

   if (!use.cros_host) {
     include_dirs += [ "${sysroot}/usr/include" ]
     cflags += [ "--sysroot=${sysroot}" ]
     ldflags += [ "--sysroot=${sysroot}" ]
   }
   if (use.profiling) {
     cflags += [
       "-fprofile-instr-generate",
       "-fcoverage-mapping",
     ]
     ldflags += [
       "-fprofile-instr-generate",
       "-fcoverage-mapping",
     ]
   }
   if (use.tcmalloc) {
     libs += [ "tcmalloc" ]
   }
 }

 config("lto_experiment") {
   # TODO(b/286954353): This is under experiment still. Please do not
   # use this in production yet until we evaluate more.
   if (use.lto_experiment) {
     cflags = [ "-flto" ]
     if (use.function_elimination_experiment) {
       cflags += [
         "-ffunction-sections",
         "-fvirtual-function-elimination",
       ]
       ldflags = [ "-Wl,--gc-sections" ]
     }
   }
 }

 # Generates position independent executable.
 # This is a default config for executables and static libraries.
 config("pie") {
   cflags = [ "-fPIE" ]

   # ldflags are not pushed to dependents, so applying ldflags to source sets or
   # static libraries will be a no-op. You can just remove "pie" config from an
   # executable to make the executable not position independent.
   ldflags = [ "-pie" ]
 }

 # Use thin archive. It makes sense only for static libraries.
 # This is a default config for static libraries.
 # Remove this and add ":nouse_thin_archive" to unuse thin archive.
 config("use_thin_archive") {
   arflags = [ "rcsT" ]
 }

 # Don't use thin archive. It makes sense only for static libraries.
 config("nouse_thin_archive") {
   arflags = [ "rcs" ]
 }

 # Generates position independent code.
 # This is a default config for shared libraries.
 config("pic") {
   cflags = [ "-fPIC" ]
 }

 # This config should be at the top in the configs list, especially before
 # the config for libchrome-${libbase-ver} to avoid weird heap-buffer-overflow
 # error from happening when ASAN is enabled.
 # TODO(crbug.com/887845): Remove this note after library order issue is resolved.
 config("test") {
   # Don't worry about overlinking, ld.gold's --as-needed will
   # deal with that.
   # TODO(crbug.com/912432): Consider use {gtest,gmock}-config --ldflags.
   # '--ldflags' is not used here. It adds, e.g., -L/usr/lib64,
   # so the test executable will be linked against host libraries if exists.
   # Specifically, libchrome for host is linked. For host, it is built with
   # -DNDEBUG, but the target built without, which causes a link error.
   # cf) BaseInitLoggingImpl definition in
   #     chromiumos/platform/libchrome/base/logging.h
   # gtest-config and gmock-config are not installed by gtest-1.8.1.
   ldflags = [
     "-pthread",

     # Allow unit tests of a shared library to link against the depended .so
     # under the output directory, instead of the ones installed in the system
     # dir. -rpath and -rpath-link has higher priority than the system library
     # directory.
     "-Wl,-rpath=\$ORIGIN/",
     "-Wl,-rpath=\$ORIGIN/lib/",
     "-Wl,-rpath-link=lib/",
   ]

   if (!use.cros_host) {
     # The path where fake libraries are installed on the host. It is
     # for tests, implementing simple backend.
     _test_lib_dir = "build/lib"
     _test_usr_local_lib_dir = "usr/local/lib"

     ldflags += [
       # The path where fake libraries are installed on the host. It is
       # for tests (e.g. fuzzer/unit tests) running on the host device.
       string_join("",
                   [
                     "-Wl,-rpath=/",
                     _test_lib_dir,
                   ]),
       string_join("",
                   [
                     "-Wl,-rpath=/",
                     _test_lib_dir,
                     "64",
                   ]),
       string_join("",
                   [
                     "-Wl,-rpath=/",
                     _test_usr_local_lib_dir,
                   ]),
       string_join("",
                   [
                     "-Wl,-rpath=/",
                     _test_usr_local_lib_dir,
                     "64",
                   ]),
     ]

     # To link against library that present an interface with a fake backend,
     # for unit testing:
     # To prevent such a library to be installed in the rootfs, the library
     # is installed in a directory in /build/$BOARD/.
     lib_dirs = [
       string_join("",
                   [
                     "${sysroot}/",
                     _test_lib_dir,
                   ]),
       string_join("",
                   [
                     "${sysroot}/",
                     _test_lib_dir,
                     "64",
                   ]),
       string_join("",
                   [
                     "${sysroot}/",
                     _test_usr_local_lib_dir,
                   ]),
       string_join("",
                   [
                     "${sysroot}/",
                     _test_usr_local_lib_dir,
                     "64",
                   ]),
     ]
   }

   # Disable legacy APIs so people are forced to upgrade.
   defines = [ "GTEST_REMOVE_LEGACY_TEST_CASEAPI_" ]

   # gnlint: disable=GnLintCommonTesting
   libs = [
     "gmock",
     "gtest",
     "pthread",
   ]
 }
	# Copyright 2018 The ChromiumOS Authors
	# Use of this source code is governed by a BSD-style license that can be
	# found in the LICENSE file.

	declare_args() {
	# Set this to false if you'd like to disable -Werror.
	enable_werror = true

	# Set this to false if you want to disable Large File Support (LFS).
	enable_lfs = true
	}

	if (use.pigweed) {
	# TODO(b/267537074) - This will fix this workaround.
	# Pigweed defaults to use CXX17 standard, update pw variable
	# to match platform2 CXX20 standard.
	dir_pigweed = "//third_party/pigweed"
	import("$dir_pigweed/pw_toolchain/traits.gni")
	pw_toolchain_CXX_STANDARD = pw_toolchain_STANDARD.CXX20
	}

	_cflags_no_exceptions = [
	"-fno-exceptions",
	"-fno-unwind-tables",
	"-fno-asynchronous-unwind-tables",
	]

	config("no_exceptions") {
	cflags_cc = _cflags_no_exceptions
	cflags_c = _cflags_no_exceptions
	}

	_gcc_cflags = [ "-Wno-psabi" ]

	config("gcc_cflags_c") {
	cflags_c = _gcc_cflags
	}
	config("gcc_cflags_cc") {
	cflags_cc = _gcc_cflags
	}

	# Note: DO NOT USE THIS. Use brillo/brillo_export.h instead to export symbols.
	#
	# Symbol visibility is set to be internal by default. Add this to your target's
	# configs to make its symbols visible.
	# Setting "-fvisibility=default" directly in your target's cflags doesn't work
	# because it will be overwritten by the "-fvisibility=internal" in the
	# compiler_defaults' cflags.
	config("visibility_default") {
	# gnlint: disable=GnLintVisibilityFlags
	cflags = [ "-fvisibility=default" ]
	}

	config("compiler_defaults") {
	defines = []
	libs = []

	include_dirs = [
	"${root_gen_dir}/include",
	"${platform2_root}",
	]
	cflags = [
	"-Wall",
	"-Wunused",
	"-Wbool-operation",
	"-Wfree-nonheap-object",
	"-Wint-in-bool-context",
	"-Wstring-compare",
	"-Wstring-plus-int",
	"-Wxor-used-as-pow",
	"-Wdeprecated-declarations",

	# We use C99 array designators in C++ code. Our compilers support this
	# extension since C++ has no equivalent yet (as of C++20).
	"-Wno-c99-designator",
	"-Wno-unused-parameter",
	"-Wunreachable-code",
	"-Wunreachable-code-return",
	"-ggdb3",
	"-fstack-protector-strong",
	"-Wformat=2",

	# When a class is exported through __attribute__((visibility("default"))),
	# we still want to eliminate symbols from inline class member functions to
	# reduce symbol resolution overhead. Therefore, pass
	# -fvisibility-inlines-hidden in addition to -fvisibility=internal.
	# (go/cros-symbol-slimming)
	"-fvisibility=internal",
	"-fvisibility-inlines-hidden",
	"-Wa,--noexecstack",
	"-Wimplicit-fallthrough",
	]
	cflags_c = [ "-std=gnu17" ] + external_cppflags + external_cxxflags
	cc_version = "-std=gnu++20"

	cflags_cc = [ cc_version ] + external_cppflags + external_cxxflags
	ldflags = external_ldflags + [
	"-Wl,-z,relro",
	"-Wl,-z,noexecstack",
	"-Wl,-z,now",
	"-Wl,--as-needed",

	# Pass -Bsymbolic-non-weak which pre-binds symbols in the same
	# DSO to improve startup performance. We don't support
	# interposing non-weak symbols. (go/cros-symbol-slimming)
	"-Wl,-Bsymbolic-non-weak",
	]
	if (link_stdcppfs) {
	libs += [ "stdc++fs" ]
	}
	if (enable_werror) {
	cflags += [
	"-Werror",

	# TODO(b/217226507): reduce the scope of this error suppression or
	# fix each case.
	"-Wno-error=deprecated-enum-enum-conversion",

	# TODO(b/217226507): some lambda capturing (specifically tests with
	# gmock) implicitly capture this, but in C++20 it should to be
	# explicit. However, this feature is not available until C++20, so
	# updating the code requires C++20 enabled.
	# For transition, suppress the error, and once C++20 is stabilized
	# we can clean up the cases.
	"-Wno-error=deprecated-this-capture",
	]
	}

	if (use.cros_host) {
	defines += [ "NDEBUG" ]
	}
	if (use.cros_debug) {
	# Initialize stack variables with values that will likely transform
	# logic bugs into crashes.
	cflags += [ "-ftrivial-auto-var-init=pattern" ]
	}
	if (enable_lfs) {
	defines += [
	# Enable support for new LFS funcs (ftello/etc...).
	"_LARGEFILE_SOURCE",

	# Enable support for 64bit variants (off64_t/fseeko64/etc...).
	"_LARGEFILE64_SOURCE",

	# Default to 64bit variants (off_t is defined as off64_t).
	"_FILE_OFFSET_BITS=64",
	]
	}

	# We only rely on `enable_exceptions` arg to control no_exceptions flags
	# (see BUILDCONFIG.gn) and ignore if the given external flags contain these
	# flags. As removing non-existing flags causes error on GN, we add them before
	# its removal to unconditionally remove them.
	cflags_cc += _cflags_no_exceptions
	cflags_c += _cflags_no_exceptions
	cflags_cc -= _cflags_no_exceptions
	cflags_c -= _cflags_no_exceptions

	if (!use.cros_host) {
	include_dirs += [ "${sysroot}/usr/include" ]
	cflags += [ "--sysroot=${sysroot}" ]
	ldflags += [ "--sysroot=${sysroot}" ]
	}
	if (use.profiling) {
	cflags += [
	"-fprofile-instr-generate",
	"-fcoverage-mapping",
	]
	ldflags += [
	"-fprofile-instr-generate",
	"-fcoverage-mapping",
	]
	}
	if (use.tcmalloc) {
	libs += [ "tcmalloc" ]
	}
	}

	config("lto_experiment") {
	# TODO(b/286954353): This is under experiment still. Please do not
	# use this in production yet until we evaluate more.
	if (use.lto_experiment) {
	cflags = [ "-flto" ]
	if (use.function_elimination_experiment) {
	cflags += [
	"-ffunction-sections",
	"-fvirtual-function-elimination",
	]
	ldflags = [ "-Wl,--gc-sections" ]
	}
	}
	}

	# Generates position independent executable.
	# This is a default config for executables and static libraries.
	config("pie") {
	cflags = [ "-fPIE" ]

	# ldflags are not pushed to dependents, so applying ldflags to source sets or
	# static libraries will be a no-op. You can just remove "pie" config from an
	# executable to make the executable not position independent.
	ldflags = [ "-pie" ]
	}

	# Use thin archive. It makes sense only for static libraries.
	# This is a default config for static libraries.
	# Remove this and add ":nouse_thin_archive" to unuse thin archive.
	config("use_thin_archive") {
	arflags = [ "rcsT" ]
	}

	# Don't use thin archive. It makes sense only for static libraries.
	config("nouse_thin_archive") {
	arflags = [ "rcs" ]
	}

	# Generates position independent code.
	# This is a default config for shared libraries.
	config("pic") {
	cflags = [ "-fPIC" ]
	}

	# This config should be at the top in the configs list, especially before
	# the config for libchrome-${libbase-ver} to avoid weird heap-buffer-overflow
	# error from happening when ASAN is enabled.
	# TODO(crbug.com/887845): Remove this note after library order issue is resolved.
	config("test") {
	# Don't worry about overlinking, ld.gold's --as-needed will
	# deal with that.
	# TODO(crbug.com/912432): Consider use {gtest,gmock}-config --ldflags.
	# '--ldflags' is not used here. It adds, e.g., -L/usr/lib64,
	# so the test executable will be linked against host libraries if exists.
	# Specifically, libchrome for host is linked. For host, it is built with
	# -DNDEBUG, but the target built without, which causes a link error.
	# cf) BaseInitLoggingImpl definition in
	# chromiumos/platform/libchrome/base/logging.h
	# gtest-config and gmock-config are not installed by gtest-1.8.1.
	ldflags = [
	"-pthread",

	# Allow unit tests of a shared library to link against the depended .so
	# under the output directory, instead of the ones installed in the system
	# dir. -rpath and -rpath-link has higher priority than the system library
	# directory.
	"-Wl,-rpath=\$ORIGIN/",
	"-Wl,-rpath=\$ORIGIN/lib/",
	"-Wl,-rpath-link=lib/",
	]

	if (!use.cros_host) {
	# The path where fake libraries are installed on the host. It is
	# for tests, implementing simple backend.
	_test_lib_dir = "build/lib"
	_test_usr_local_lib_dir = "usr/local/lib"

	ldflags += [
	# The path where fake libraries are installed on the host. It is
	# for tests (e.g. fuzzer/unit tests) running on the host device.
	string_join("",
	[
	"-Wl,-rpath=/",
	_test_lib_dir,
	]),
	string_join("",
	[
	"-Wl,-rpath=/",
	_test_lib_dir,
	"64",
	]),
	string_join("",
	[
	"-Wl,-rpath=/",
	_test_usr_local_lib_dir,
	]),
	string_join("",
	[
	"-Wl,-rpath=/",
	_test_usr_local_lib_dir,
	"64",
	]),
	]

	# To link against library that present an interface with a fake backend,
	# for unit testing:
	# To prevent such a library to be installed in the rootfs, the library
	# is installed in a directory in /build/$BOARD/.
	lib_dirs = [
	string_join("",
	[
	"${sysroot}/",
	_test_lib_dir,
	]),
	string_join("",
	[
	"${sysroot}/",
	_test_lib_dir,
	"64",
	]),
	string_join("",
	[
	"${sysroot}/",
	_test_usr_local_lib_dir,
	]),
	string_join("",
	[
	"${sysroot}/",
	_test_usr_local_lib_dir,
	"64",
	]),
	]
	}

	# Disable legacy APIs so people are forced to upgrade.
	defines = [ "GTEST_REMOVE_LEGACY_TEST_CASEAPI_" ]

	# gnlint: disable=GnLintCommonTesting
	libs = [
	"gmock",
	"gtest",
	"pthread",
	]
	}