# Copyright 2018 Google LLC
#
# 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.

# Target toolchain specific build arguments.
declare_args() {
  # Build with a specific compiler version e.g. when building with clang, set
  # to "3.9" to build with `clang-3.9`.
  arch_cc_version = ""
}

# Template for target toolchains; there is no support for C++ or libraries.
# Instead, use source_set to group source together.
template("cc_toolchain") {
  toolchain(target_name) {
    assert(defined(invoker.cc), "cc_toolchain() must specify a \"cc\" value")
    assert(defined(invoker.ld), "cc_toolchain() must specify a \"ld\" value")

    # Combine compiler version and compiler specific flags for this toolchain.
    cc = "${invoker.cc}"
    if (arch_cc_version != "") {
      cc += "-${arch_cc_version}"
    }
    if (defined(invoker.cflags)) {
      cc += " ${invoker.cflags}"
    }

    tool("cc") {
      depfile = "{{output}}.d"
      command = "${cc} -MMD -MF $depfile {{defines}} {{include_dirs}} {{cflags}} {{cflags_c}} -c {{source}} -o {{output}}"
      depsformat = "gcc"
      description = "CC {{output}}"
      outputs = [
        "{{source_out_dir}}/{{target_output_name}}.{{source_name_part}}.o",
      ]
    }

    tool("asm") {
      depfile = "{{output}}.d"
      command = "${cc} -MMD -MF $depfile {{defines}} {{include_dirs}} {{asmflags}} -c {{source}} -o {{output}}"
      depsformat = "gcc"
      description = "ASM {{output}}"
      outputs = [
        "{{source_out_dir}}/{{target_output_name}}.{{source_name_part}}.o",
      ]
    }

    tool("link") {
      outfile = "{{output_dir}}/{{target_output_name}}{{output_extension}}"
      rspfile = "$outfile.rsp"
      command = "${invoker.ld} {{ldflags}} -o $outfile --start-group @$rspfile --end-group"
      description = "LINK $outfile"
      default_output_dir = "{{root_out_dir}}"
      rspfile_content = "{{inputs}}"
      outputs = [
        outfile,
      ]
    }

    tool("stamp") {
      command = "touch {{output}}"
      description = "STAMP {{output}}"
    }

    tool("copy") {
      command = "cp -af {{source}} {{output}}"
      description = "COPY {{source}} {{output}}"
    }

    toolchain_args = {
      forward_variables_from(invoker.toolchain_args, "*")
    }
  }
}

# Specialize for clang or gcc
template("clang_toolchain") {
  assert(defined(invoker.target),
         "clang_toolchain() must specify a \"target\" value")
  assert(defined(invoker.arch_tool_prefix),
         "gcc_toolchain() must specify a \"arch_tool_prefix\" value")

  cc_toolchain(target_name) {
    cc = "clang"
    cflags = "-target ${invoker.target} -fcolor-diagnostics"
    ld = "ld.lld --color-diagnostics -O2 -lto-O2 --icf=all --fatal-warnings"

    toolchain_args = {
      arch_tool_prefix = invoker.arch_tool_prefix
    }
  }
}

template("gcc_toolchain") {
  assert(defined(invoker.arch_tool_prefix),
         "gcc_toolchain() must specify a \"arch_tool_prefix\" value")

  cc_toolchain(target_name) {
    cc = "${invoker.arch_tool_prefix}gcc"
    cflags = "-fdiagnostics-color=always"
    ld = "${invoker.arch_tool_prefix}ld"

    toolchain_args = {
      arch_tool_prefix = invoker.arch_tool_prefix
    }
  }
}

# Specialize for different architectures

clang_toolchain("clang_aarch64") {
  target = "aarch64-none-eabi"

  # TODO: below isn't right for bare metal code, but it works fine
  arch_tool_prefix = "aarch64-linux-gnu-"
}

gcc_toolchain("gcc_aarch64") {
  # TODO: below isn't right for bare metal code, but it works fine
  arch_tool_prefix = "aarch64-linux-gnu-"
}