dawn-cmake/scripts/dawn_component.gni

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# Copyright 2019 The Dawn Authors
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
import("//build_overrides/build.gni")
import("dawn_features.gni")
import("dawn_overrides_with_defaults.gni")
###############################################################################
# Template to produce a component for one of Dawn's libraries.
###############################################################################
# Template that produces static and shared versions of the same library as well
# as a target similar to Chromium's component targets.
# - The shared version exports symbols and has dependent import the symbols
# as libdawn_${name}.so. If the target name matches the package directory
# name, then the shared library target will be named 'shared', otherwise
# '${target_name}_shared'.
# - The static library doesn't export symbols nor make dependents import them.
# If the target name matches the package directory name, then the static
# library target will be named 'static', otherwise '${target_name}_static'.
# - The libname target is similar to a Chromium component and is an alias for
# either the static or the shared library.
#
# The DEFINE_PREFIX must be provided and must match the respective "_export.h"
# file.
#
# Example usage:
#
# dawn_component("my_library") {
# // my_library_export.h must use the MY_LIBRARY_IMPLEMENTATION and
# // MY_LIBRARY_SHARED_LIBRARY macros.
# DEFINE_PREFIX = "MY_LIBRARY"
#
# sources = [...]
# deps = [...]
# configs = [...]
# }
#
# executable("foo") {
# deps = [ ":my_library_shared" ] // or :my_library for the same effect
# }
template("dawn_component") {
# Copy the target_name in the local scope so it doesn't get shadowed in the
# definition of targets.
name = target_name
prefix = "${name}_"
# Remove prefix if the target name matches directory
if (get_label_info(get_label_info(":$target_name", "dir"), "name") == name) {
prefix = ""
}
# The config that will apply to dependents of the shared library so they know
# they should "import" the symbols
config("${prefix}shared_public_config") {
defines = [ "${invoker.DEFINE_PREFIX}_SHARED_LIBRARY" ]
# Executable needs an rpath to find our shared libraries on OSX and Linux
if (is_mac) {
ldflags = [
"-rpath",
"@executable_path/",
]
}
if ((is_linux || is_chromeos) && dawn_has_build) {
configs = [ "//build/config/gcc:rpath_for_built_shared_libraries" ]
}
}
shared_library("${prefix}shared") {
# The "tool" for creating shared libraries will automatically add the "lib" prefix
output_name = "dawn_${name}"
# Copy all variables except "configs", which has a default value
forward_variables_from(invoker, "*", [ "configs" ])
if (defined(invoker.configs)) {
configs += invoker.configs
}
# Tell dependents where to find this shared library
if (is_mac) {
ldflags = [
"-install_name",
"@rpath/lib${name}.dylib",
]
}
# Use the config that makes the ${DEFINE_PREFIX}_EXPORT macro do something
if (!defined(public_configs)) {
public_configs = []
}
public_configs += [ ":${prefix}shared_public_config" ]
# Tell sources of this library to export the symbols (and not import)
if (!defined(defines)) {
defines = []
}
defines += [ "${invoker.DEFINE_PREFIX}_IMPLEMENTATION" ]
# Chromium adds a config that uses a special linker script that removes
# all symbols except JNI ones. Remove this config so that our
# shared_library symbols are visible. This matches what Chromium's
# component template does.
if (build_with_chromium && is_android) {
configs -= [ "//build/config/android:hide_all_but_jni_onload" ]
}
}
static_library("${prefix}static") {
output_name = "dawn_${name}_static"
complete_static_lib = dawn_complete_static_libs
# Copy all variables except "configs", which has a default value
forward_variables_from(invoker, "*", [ "configs" ])
if (defined(invoker.configs)) {
configs += invoker.configs
}
}
group(name) {
if (is_component_build) {
public_deps = [ ":${prefix}shared" ]
} else {
public_deps = [ ":${prefix}static" ]
}
}
}