| # Copyright 2020 The Pigweed 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 |
| # |
| # https://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("//build_overrides/pigweed.gni") |
| |
| import("$dir_pw_build/exec.gni") |
| import("$dir_pw_build/target_types.gni") |
| import("$dir_pw_toolchain/generate_toolchain.gni") |
| |
| # Preprocess a linker script and turn it into a target. |
| # |
| # In lieu of direct GN support for linker scripts, this template makes it |
| # possible to run the C Preprocessor on a linker script file so defines can |
| # be properly evaluated before the linker script is passed to the dir_pw_build |
| # |
| # TODO(pwbug/53): This template serves as a stand-in until native GN support for |
| # linker scripts is added. |
| # |
| # Args: |
| # linker_script: The linker script to send through the C preprocessor. |
| # |
| # defines: Preprocessor defines to apply when running the C preprocessor. |
| # |
| # cflags: Flags to pass to the C compiler. |
| # |
| # includes: Include these files when running the C preprocessor. |
| # |
| # inputs: Files that, when changed, should trigger a re-build of the linker |
| # script. linker_script and includes are implicitly added to this by the |
| # template. |
| # |
| # Example: |
| # |
| # pw_linker_script("generic_linker_script") { |
| # defines = [ |
| # "PW_HEAP_SIZE=1K", |
| # "PW_NOINIT_SIZE=512" |
| # ] |
| # linker_script = "basic_script.ld" |
| # } |
| # |
| template("pw_linker_script") { |
| assert( |
| defined(invoker.linker_script) && invoker.linker_script != "", |
| "$target_name did not set `linker_script` to refer to a valid linker " + |
| "script. This variable is required for linker script targets.") |
| |
| _final_linker_script = "${target_gen_dir}/${target_name}_final.ld" |
| |
| # This action invokes the C compiler provided by the target to preprocess the |
| # linker script. |
| pw_exec("${target_name}_preprocess") { |
| program = pw_toolchain_SCOPE.cxx |
| inputs = [ invoker.linker_script ] |
| args = [ |
| # Run compiler in preprocessor-only mode. |
| "-E", |
| |
| # Do not generate linemarkers in output. |
| "-P", |
| |
| # Do not discard comments. |
| "-C", |
| |
| # Treat the following file as a C file. |
| "-x", |
| "c", |
| rebase_path(invoker.linker_script, root_build_dir), |
| ] |
| |
| # Trigger a re-generation of the linker script when these inputs change. |
| if (defined(invoker.inputs)) { |
| inputs += invoker.inputs |
| } |
| |
| # Include any explicitly listed C flags. |
| if (defined(invoker.cflags)) { |
| args += invoker.cflags |
| } |
| |
| # Include files from the command line. |
| if (defined(invoker.includes)) { |
| inputs += invoker.includes |
| foreach(include_file, invoker.includes) { |
| args += [ "-include" + rebase_path(include_file, root_build_dir) ] |
| } |
| } |
| |
| # Add defines. |
| if (defined(invoker.defines)) { |
| foreach(compiler_define, invoker.defines) { |
| args += [ "-D${compiler_define}" ] |
| } |
| } |
| |
| # Set output file. |
| args += [ |
| "-o", |
| rebase_path(_final_linker_script, root_build_dir), |
| ] |
| outputs = [ _final_linker_script ] |
| } |
| |
| # This config adds a the linker script produced by the preprocess action to |
| # the linker flags. |
| config("${target_name}_config") { |
| inputs = [ invoker.linker_script ] |
| if (!defined(invoker.ldflags)) { |
| ldflags = [] |
| } |
| ldflags += [ "-T" + rebase_path(_final_linker_script, root_build_dir) ] |
| } |
| |
| # The target that adds the linker script config to this library and everything |
| # that depends on it. |
| pw_source_set(target_name) { |
| inputs = [ _final_linker_script ] |
| all_dependent_configs = [ ":${target_name}_config" ] |
| deps = [ ":${target_name}_preprocess" ] |
| } |
| } |