1# Copyright 2019 The Dawn Authors 2# 3# Licensed under the Apache License, Version 2.0 (the "License"); 4# you may not use this file except in compliance with the License. 5# You may obtain a copy of the License at 6# 7# http://www.apache.org/licenses/LICENSE-2.0 8# 9# Unless required by applicable law or agreed to in writing, software 10# distributed under the License is distributed on an "AS IS" BASIS, 11# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 12# See the License for the specific language governing permissions and 13# limitations under the License. 14 15import("../scripts/dawn_overrides_with_defaults.gni") 16import("generator_lib.gni") 17 18# Dawn used to put autogenerated files in a lot of different places. When we 19# started to move them around, some compilation issues arised because some 20# stale include files stayed in the build directory and were picked up. 21# To counter this, now Dawn does the following: 22# 23# 1. The generated output file directory structure has to match the structure 24# of the source tree, starting at dawn_gen_root (gen/ or 25# gen/third_party/dawn depending on where we are). 26# 2. src/include and dawn_gen_root/src/include has to match the structure of 27# the source tree too. 28# 3. Dawn files must use include relative to src/ or src/include such as 29# "dawn/dawn.h" or "dawn_native/backend/BackendStuff.h". 30# 31# The allowed list below ensure 1). Include directory rules for Dawn ensure 3) 32# and 2) is something we need to enforce in code review. 33# 34# However GN's toolchains automatically add some include directories for us 35# which breaks 3) slightly. To avoid stale headers in for example 36# dawn_gen_root/src/dawn/dawn/ to be picked up (instead of 37# dawn_gen_root/src/dawn), we have a special action that removes files in 38# disallowed gen directories. 39 40dawn_allowed_gen_output_dirs = [ 41 "src/dawn/", 42 "src/dawn_native/", 43 "src/dawn_native/opengl/", 44 "src/dawn_wire/client/", 45 "src/dawn_wire/server/", 46 "src/dawn_wire/", 47 "src/include/dawn/", 48 "emscripten-bits/", 49 "webgpu-headers/", 50] 51 52# Template to help invoking Dawn code generators based on generator_lib 53# 54# dawn_generator("my_target_gen") { 55# # The script and generator specific arguments 56# script = [ "my_awesome_generator.py" ] 57# args = [ 58# "--be-awesome", 59# "yes" 60# ] 61# 62# # The list of expected outputs, generation fails if there's a mismatch 63# outputs = [ 64# "MyAwesomeTarget.cpp", 65# "MyAwesomeTarget.h", 66# ] 67# } 68# 69# Using the generated files is done like so: 70# 71# shared_library("my_target") { 72# deps = [ ":my_target_gen "] 73# sources = get_target_outputs(":my_target_gen") 74# } 75# 76template("dawn_generator") { 77 generator_lib_action(target_name) { 78 forward_variables_from(invoker, "*") 79 80 # Set arguments required to find the python libraries for the generator 81 generator_lib_dir = "${dawn_root}/generator" 82 jinja2_path = dawn_jinja2_dir 83 84 # Force Dawn's autogenerated file structure to mirror exactly the source 85 # tree but start at ${dawn_gen_root} instead of ${dawn_root} 86 allowed_output_dirs = dawn_allowed_gen_output_dirs 87 custom_gen_dir = dawn_gen_root 88 89 # Make sure that we delete stale autogenerated file in directories that are 90 # no longer used by code generation to avoid include conflicts. 91 deps = [ "${dawn_root}/generator:remove_stale_autogen_files" ] 92 } 93} 94 95# Helper generator for calling the generator from dawn.json 96# 97# dawn_json_generator("my_target_gen") { 98# # Which generator target to output 99# target = "my_target" 100# 101# # Also supports `outputs` and `custom_gen_dir` like dawn_generator. 102# } 103template("dawn_json_generator") { 104 dawn_generator(target_name) { 105 script = "${dawn_root}/generator/dawn_json_generator.py" 106 107 # The base arguments for the generator: from this dawn.json, generate this 108 # target using templates in this directory. 109 args = [ 110 "--dawn-json", 111 rebase_path("${dawn_root}/dawn.json", root_build_dir), 112 "--wire-json", 113 rebase_path("${dawn_root}/dawn_wire.json", root_build_dir), 114 "--targets", 115 invoker.target, 116 ] 117 118 forward_variables_from(invoker, "*", [ "target" ]) 119 } 120} 121