1# Copyright 2021 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
15# Declares a group that builds a list of dependencies using multiple toolchains.
16#
17# In a multi-toolchain group, each dependency is built with each of the provided
18# toolchains. This results in M x N targets being built, where M is the number
19# of toolchains, and N is the number of targets listed in the `deps` variable.
20#
21# This template is useful for simplifying cases where you have multiple
22# applications you would like to build under different toolchain contexts.
23#
24# Args:
25#   deps: (required) List of GN targets to build under each listed toolchain.
26#   toolchains: (required) A list of toolchain labels to build the dependencies
27#     with.
28template("pw_multi_toolchain_group") {
29  assert(!defined(invoker.public_deps),
30         "Use `deps` for pw_multi_toolchain_group targets")
31  assert(defined(invoker.deps), "`deps` must be defined to use this template")
32  assert(defined(invoker.toolchains),
33         "`toolchains` must be defined to use this template")
34  group(target_name) {
35    deps = []
36    public_deps = []
37    foreach(tc, invoker.toolchains) {
38      foreach(item, invoker.deps) {
39        # Make sure targets don't explicitly reference a toolchain in their
40        # target label. If we poison any instances of "(", we can see a mismatch
41        # against the original string, indicating a toolchain was explicitly
42        # specified.
43        _poisioned_label = string_replace(item, "(", "!")
44        assert(item == _poisioned_label,
45               "$item can't explicitly specify a toolchain as part of " +
46                   "a multi-toolchain group")
47        deps += [ "$item($tc)" ]
48      }
49    }
50  }
51}
52