# Copyright 2021 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_toolchain/universal_tools.gni")

declare_args() {
  # Regular expressions matching the paths of the source files to be excluded
  # from the analysis. clang-tidy provides no alternative option.
  #
  # For example, the following disables clang-tidy on all source files in the
  # third_party directory:
  #
  #   pw_toolchain_STATIC_ANALYSIS_SKIP_SOURCES_RES = ["third_party/.*"]
  #
  pw_toolchain_STATIC_ANALYSIS_SKIP_SOURCES_RES = []

  # Disable clang-tidy for specific include paths. In the clang-tidy command,
  # include paths that end with one of these, or match as a regular expression,
  # are switched from -I to -isystem, which causes clang-tidy to ignore them.
  # Unfortunately, clang-tidy provides no other way to filter header files.
  #
  # For example, the following ignores header files in "mbedtls/include":
  #
  #   pw_toolchain_STATIC_ANALYSIS_SKIP_INCLUDE_PATHS = ["mbedtls/include"]
  #
  # While the following ignores all third-party header files:
  #
  #   pw_toolchain_STATIC_ANALYSIS_SKIP_INCLUDE_PATHS = [".*/third_party/.*"]
  #
  pw_toolchain_STATIC_ANALYSIS_SKIP_INCLUDE_PATHS = []
}

# Creates a toolchain target for static analysis.
#
# The generated toolchain runs clang-tidy on all source files that are not
# excluded by pw_toolchain_STATIC_ANALYSIS_SKIP_SOURCES_RES or
# pw_toolchain_STATIC_ANALYSIS_SKIP_INCLUDE_PATHS.
#
# Args:
#   cc: (required) String indicating the C compiler to use.
#   cxx: (required) String indicating the C++ compiler to use.
template("pw_static_analysis_toolchain") {
  invoker_toolchain_args = invoker.defaults

  # Clang tidy is invoked by a wrapper script which implements the missing
  # option --source-filter.
  _clang_tidy_py_path =
      rebase_path("$dir_pw_toolchain/py/pw_toolchain/clang_tidy.py",
                  root_build_dir)
  _clang_tidy_py = "${python_path} ${_clang_tidy_py_path}"
  _source_root = rebase_path("//", root_build_dir)
  _source_exclude = ""
  foreach(pattern, pw_toolchain_STATIC_ANALYSIS_SKIP_SOURCES_RES) {
    _source_exclude = _source_exclude + " --source-exclude '${pattern}'"
  }

  _skip_include_path =
      "--skip-include-path " +
      string_join(" ", pw_toolchain_STATIC_ANALYSIS_SKIP_INCLUDE_PATHS)

  toolchain(target_name) {
    # Uncomment this line to see which toolchains generate other toolchains.
    # print("Generating toolchain: ${target_name} by ${current_toolchain}")

    tool("asm") {
      depfile = "{{output}}.d"
      command = pw_universal_stamp.command
      depsformat = "gcc"
      description = "as {{output}}"
      outputs = [
        # Use {{source_file_part}}, which includes the extension, instead of
        # {{source_name_part}} so that object files created from <file_name>.c
        # and <file_name>.cc sources are unique.
        "{{source_out_dir}}/{{target_output_name}}.{{source_file_part}}.o",
      ]
    }

    assert(defined(invoker.cc), "toolchain is missing 'cc'")
    tool("cc") {
      depfile = "{{output}}.d"
      command = string_join(" ",
                            [
                              _clang_tidy_py,
                              _source_exclude,
                              _skip_include_path,
                              "--source-file {{source}}",
                              "--source-root '${_source_root}'",
                              "--export-fixes {{output}}.yaml",
                              "--",
                              invoker.cc,
                              "-MMD -MF $depfile",  # Write out dependencies.
                              "{{cflags}}",
                              "{{cflags_c}}",  # Must come after {{cflags}}.
                              "{{defines}}",
                              "{{include_dirs}}",
                              "-c {{source}}",
                              "-o {{output}}",
                            ]) + " && touch {{output}}"
      depsformat = "gcc"
      description = "clang-tidy {{source}}"
      outputs =
          [ "{{source_out_dir}}/{{target_output_name}}.{{source_file_part}}.o" ]
    }

    assert(defined(invoker.cxx), "toolchain is missing 'cxx'")
    tool("cxx") {
      depfile = "{{output}}.d"
      command = string_join(" ",
                            [
                              _clang_tidy_py,
                              _source_exclude,
                              _skip_include_path,
                              "--source-file {{source}}",
                              "--source-root '${_source_root}'",
                              "--export-fixes {{output}}.yaml",
                              "--",
                              invoker.cxx,
                              "-MMD -MF $depfile",  # Write out dependencies.
                              "{{cflags}}",
                              "{{cflags_cc}}",  # Must come after {{cflags}}.
                              "{{defines}}",
                              "{{include_dirs}}",
                              "-c {{source}}",
                              "-o {{output}}",
                            ]) + " && touch {{output}}"
      depsformat = "gcc"
      description = "clang-tidy {{source}}"
      outputs =
          [ "{{source_out_dir}}/{{target_output_name}}.{{source_file_part}}.o" ]
    }

    tool("objc") {
      depfile = "{{output}}.d"
      command = pw_universal_stamp.command
      depsformat = "gcc"
      description = "objc {{source}}"
      outputs =
          [ "{{source_out_dir}}/{{target_output_name}}.{{source_file_part}}.o" ]
    }

    tool("objcxx") {
      depfile = "{{output}}.d"
      command = pw_universal_stamp.command
      depsformat = "gcc"
      description = "objc++ {{output}}"
      outputs =
          [ "{{source_out_dir}}/{{target_output_name}}.{{source_file_part}}.o" ]
    }

    tool("alink") {
      command = "rm -f {{output}} && touch {{output}}"
      description = "ar {{target_output_name}}{{output_extension}}"
      outputs = [ "{{output_dir}}/{{target_output_name}}{{output_extension}}" ]
      default_output_extension = ".a"
      default_output_dir = "{{target_out_dir}}/lib"
    }

    tool("link") {
      if (host_os == "win") {
        # Force the extension to '.bat', empty bat scripts are still
        # executable and will not raise errors.
        _output = "{{output_dir}}/{{target_output_name}}.bat"
        command = pw_universal_stamp.command
        default_output_extension = ".bat"
      } else {
        default_output_extension = ""
        _output = "{{output_dir}}/{{target_output_name}}{{output_extension}}"
        command = "touch {{output}} && chmod +x {{output}}"
      }
      description = "ld $_output"
      outputs = [ _output ]
      default_output_dir = "{{target_out_dir}}/bin"
    }

    tool("solink") {
      _output = "{{output_dir}}/{{target_output_name}}{{output_extension}}"
      command = pw_universal_stamp.command
      description = "ld -shared $_output"
      outputs = [ _output ]
      default_output_dir = "{{target_out_dir}}/lib"
      default_output_extension = ".so"
    }

    tool("stamp") {
      # GN-ism: GN gets mad if you directly forward the contents of
      # pw_universal_stamp.
      _stamp = pw_universal_stamp
      forward_variables_from(_stamp, "*")
    }

    tool("copy") {
      # GN-ism: GN gets mad if you directly forward the contents of
      # pw_universal_copy.
      _copy = pw_universal_copy
      forward_variables_from(_copy, "*")
    }

    # Build arguments to be overridden when compiling cross-toolchain:
    #
    #   pw_toolchain_defaults: A scope setting defaults to apply to GN targets
    #     in this toolchain. It is analogous to $pw_target_defaults in
    #     $dir_pigweed/pw_vars_default.gni.
    #
    #   pw_toolchain_SCOPE: A copy of the invoker scope that defines the
    #     toolchain. Used for generating derivative toolchains.
    #
    toolchain_args = {
      pw_toolchain_SCOPE = {
      }
      pw_toolchain_SCOPE = {
        forward_variables_from(invoker, "*")
        name = target_name
      }
      forward_variables_from(invoker_toolchain_args, "*")
    }
  }
}