1# Copyright 2020 The Pigweed Authors
2#
3# Licensed under the Apache License, Version 2.0 (the "License"); you may not
4# use this file except in compliance with the License. You may obtain a copy of
5# the License at
6#
7#     https://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, WITHOUT
11# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
12# License for the specific language governing permissions and limitations under
13# the License.
14
15import("//build_overrides/pigweed.gni")
16
17import("$dir_pw_toolchain/generate_toolchain.gni")
18
19# Generates a toolchain using the currently active toolchain as a foundation.
20# WARNING: Only works with toolchains generated by Pigweed's generate_toolchain.
21# WARNING: This can quickly create an explosion of toolchains and compile times.
22#   Use sparingly!
23#
24# Args:
25#   build_args: (required) A scope setting GN build arg values to apply to GN
26#     targets in this toolchain. These take precedence over args.gni settings,
27#     and any build_args set by the currently active toolchain.
28#   (other): You can optionally override all other generate_toolchain args. See
29#     that template's documentation for more information.
30template("pw_generate_subtoolchain") {
31  assert(defined(invoker.build_args), "Sub-toolchain is missing 'build_args'")
32  _original_scope = pw_toolchain_SCOPE
33  assert(defined(_original_scope.name),
34         "Sub-toolchain must be generated from a Pigweed toolchain")
35
36  generate_toolchain(target_name) {
37    forward_variables_from(_original_scope, "*", [ "defaults" ])
38    forward_variables_from(invoker, "*", [ "build_args" ])
39
40    # Subtoolchains must always be generated from the toolchain that parses
41    # them rather than relying on the default_toolchain.
42    generate_from = current_toolchain
43    defaults = {
44      forward_variables_from(_original_scope.defaults, "*")
45      forward_variables_from(invoker.build_args, "*")
46    }
47  }
48}
49