dawn-cmake/generator/dawn_generator.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("../scripts/dawn_overrides_with_defaults.gni")
import("generator_lib.gni")
# Dawn used to put autogenerated files in a lot of different places. When we
# started to move them around, some compilation issues arised because some
# stale include files stayed in the build directory and were picked up.
# To counter this, now Dawn does the following:
#
# 1. The generated output file directory structure has to match the structure
# of the source tree, starting at dawn_gen_root (gen/ or
# gen/third_party/dawn depending on where we are).
# 2. src/include and dawn_gen_root/src/include has to match the structure of
# the source tree too.
# 3. Dawn files must use include relative to src/ or src/include such as
# "dawn/dawn.h" or "dawn/native/backend/BackendStuff.h".
#
# The allowed list below ensure 1). Include directory rules for Dawn ensure 3)
# and 2) is something we need to enforce in code review.
#
# However GN's toolchains automatically add some include directories for us
# which breaks 3) slightly. To avoid stale headers in for example
# dawn_gen_root/src/dawn/dawn/ to be picked up (instead of
# dawn_gen_root/src/dawn), we have a special action that removes files in
# disallowed gen directories.
dawn_allowed_gen_output_dirs = [
"src/dawn/",
"src/dawn/native/",
"src/dawn/native/opengl/",
"src/dawn/wire/client/",
"src/dawn/wire/server/",
"src/dawn/wire/",
"src/include/dawn/",
"emscripten-bits/",
"webgpu-headers/",
]
# Template to help invoking Dawn code generators based on generator_lib
#
# dawn_generator("my_target_gen") {
# # The script and generator specific arguments
# script = [ "my_awesome_generator.py" ]
# args = [
# "--be-awesome",
# "yes"
# ]
#
# # The list of expected outputs, generation fails if there's a mismatch
# outputs = [
# "MyAwesomeTarget.cpp",
# "MyAwesomeTarget.h",
# ]
# }
#
# Using the generated files is done like so:
#
# shared_library("my_target") {
# deps = [ ":my_target_gen "]
# sources = get_target_outputs(":my_target_gen")
# }
#
template("dawn_generator") {
generator_lib_action(target_name) {
forward_variables_from(invoker, "*")
# Set arguments required to find the python libraries for the generator
generator_lib_dir = "${dawn_root}/generator"
jinja2_path = dawn_jinja2_dir
# Force Dawn's autogenerated file structure to mirror exactly the source
# tree but start at ${dawn_gen_root} instead of ${dawn_root}
allowed_output_dirs = dawn_allowed_gen_output_dirs
custom_gen_dir = dawn_gen_root
# Make sure that we delete stale autogenerated file in directories that are
# no longer used by code generation to avoid include conflicts.
deps = [ "${dawn_root}/generator:remove_stale_autogen_files" ]
}
}
# Helper generator for calling the generator from dawn.json
#
# dawn_json_generator("my_target_gen") {
# # Which generator target to output
# target = "my_target"
#
# # Also supports `outputs` and `custom_gen_dir` like dawn_generator.
# }
template("dawn_json_generator") {
dawn_generator(target_name) {
script = "${dawn_root}/generator/dawn_json_generator.py"
# The base arguments for the generator: from this dawn.json, generate this
# target using templates in this directory.
args = [
"--dawn-json",
rebase_path("${dawn_root}/dawn.json", root_build_dir),
"--wire-json",
rebase_path("${dawn_root}/dawn_wire.json", root_build_dir),
"--targets",
invoker.target,
]
forward_variables_from(invoker, "*", [ "target" ])
}
}