1 # Copyright 2020 The Pigweed Authors
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
7 # https://www.apache.org/licenses/LICENSE-2.0
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
15 import("//build_overrides/pigweed.gni")
17 import("$dir_pw_build/exec.gni")
18 import("$dir_pw_build/target_types.gni")
19 import("$dir_pw_toolchain/generate_toolchain.gni")
21 # Preprocess a linker script and turn it into a target.
23 # In lieu of direct GN support for linker scripts, this template makes it
24 # possible to run the C Preprocessor on a linker script file so defines can
25 # be properly evaluated before the linker script is passed to the dir_pw_build
27 # TODO(pwbug/53): This template serves as a stand-in until native GN support for
28 # linker scripts is added.
31 # linker_script: The linker script to send through the C preprocessor.
33 # defines: Preprocessor defines to apply when running the C preprocessor.
35 # cflags: Flags to pass to the C compiler.
37 # inputs: Files that, when changed, should trigger a re-build of the linker
38 # script. linker_script is implicitly added to this by the template.
42 # pw_linker_script("generic_linker_script") {
45 # "PW_NOINIT_SIZE=512"
47 # linker_script = "basic_script.ld"
50 template("pw_linker_script") {
52 defined(invoker.linker_script) && invoker.linker_script != "",
53 "$target_name did not set `linker_script` to refer to a valid linker " +
54 "script. This variable is required for linker script targets.")
56 _final_linker_script = "${target_gen_dir}/${target_name}_final.ld"
58 # This action invokes the C compiler provided by the target to preprocess the
60 pw_exec("${target_name}_preprocess") {
61 program = pw_toolchain_SCOPE.cxx
62 inputs = [ invoker.linker_script ]
64 # Run compiler in preprocessor-only mode.
67 # Do not generate linemarkers in output.
70 # Do not discard comments.
73 # Treat the following file as a C file.
76 rebase_path(invoker.linker_script),
79 # Include any explicitly listed c flags.
80 if (defined(invoker.cflags)) {
85 if (defined(invoker.defines)) {
86 foreach(compiler_define, invoker.defines) {
87 args += [ "-D${compiler_define}" ]
94 rebase_path(_final_linker_script),
96 outputs = [ _final_linker_script ]
99 # This config adds a the linker script produced by the preprocess action to
101 config("${target_name}_config") {
102 inputs = [ invoker.linker_script ]
103 if (!defined(invoker.ldflags)) {
106 ldflags += [ "-T" + rebase_path(_final_linker_script) ]
109 # The target that adds the linker script config to this library and everything
110 # that depends on it.
111 pw_source_set(target_name) {
112 inputs = [ _final_linker_script ]
113 if (defined(invoker.inputs)) {
114 inputs += invoker.inputs
116 all_dependent_configs = [ ":${target_name}_config" ]
117 deps = [ ":${target_name}_preprocess" ]