# 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.

declare_args() {
  # Set by arch toolchain. Prefix for binutils tools.
  tool_prefix = ""
}

# Template for embedded toolchains; there is no support for C++ or libraries.
# Instead, use source_set to group source together.
template("embedded_cc_toolchain") {
  toolchain(target_name) {
    assert(defined(invoker.cc), "\"cc\" must be defined for ${target_name}.")
    assert(defined(invoker.ld), "\"ld\" must be defined for ${target_name}.")

    # Collect extra flags from the toolchain.
    extra_defines = ""
    extra_cflags = "-flto -ffunction-sections -fdata-sections"
    extra_ldflags = "--gc-sections -pie"
    if (defined(invoker.extra_defines)) {
      extra_defines += " ${invoker.extra_defines}"
    }
    if (defined(invoker.extra_cflags)) {
      extra_cflags += " ${invoker.extra_cflags}"
    }
    if (defined(invoker.extra_ldflags)) {
      extra_ldflags += " ${invoker.extra_ldflags}"
    }

    # Define the tools.
    tool("cc") {
      depfile = "{{output}}.d"
      command = "${invoker.cc} -MMD -MF $depfile ${extra_defines} {{defines}} {{include_dirs}} ${extra_cflags} {{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 = "${invoker.cc} -MMD -MF $depfile ${extra_defines} {{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} ${extra_ldflags} {{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.
template("embedded_clang_toolchain") {
  assert(defined(invoker.target),
         "\"target\" must be defined for ${target_name}.")
  assert(defined(invoker.tool_prefix),
         "\"tool_prefix\" must be defined for ${target_name}.")

  embedded_cc_toolchain(target_name) {
    cc = "clang -target ${invoker.target} -fcolor-diagnostics"
    ld = "ld.lld --color-diagnostics"

    extra_defines = ""
    extra_cflags = ""
    extra_ldflags = "-O2 -lto-O2 --icf=all --fatal-warnings"
    if (defined(invoker.extra_defines)) {
      extra_defines += " ${invoker.extra_defines}"
    }
    if (defined(invoker.extra_cflags)) {
      extra_cflags += " ${invoker.extra_cflags}"
    }
    if (defined(invoker.extra_ldflags)) {
      extra_ldflags += " ${invoker.extra_ldflags}"
    }

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

# Specialize for gcc.
template("embedded_gcc_toolchain") {
  assert(defined(invoker.tool_prefix),
         "\"tool_prefix\" must be defined for ${target_name}.")

  embedded_cc_toolchain(target_name) {
    cc = "${invoker.tool_prefix}gcc -fdiagnostics-color=always"
    ld = "${invoker.tool_prefix}ld"

    extra_defines = ""
    extra_cflags = ""
    extra_ldflags = ""
    if (defined(invoker.extra_defines)) {
      extra_defines += " ${invoker.extra_defines}"
    }
    if (defined(invoker.extra_cflags)) {
      extra_cflags += " ${invoker.extra_cflags}"
    }
    if (defined(invoker.extra_ldflags)) {
      extra_ldflags += " ${invoker.extra_ldflags}"
    }

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

# Expand to clang and gcc variants.
template("embedded_platform_toolchain") {
  assert(defined(invoker.arch), "\"arch\" must be defined for ${target_name}.")
  assert(defined(invoker.target),
         "\"target\" must be defined for ${target_name}.")
  assert(defined(invoker.tool_prefix),
         "\"tool_prefix\" must be defined for ${target_name}.")
  assert(defined(invoker.origin_address),
         "\"origin_address\" must be defined for ${target_name}.")
  assert(defined(invoker.max_cpus),
         "\"max_cpus\" must be defined for ${target_name}.")
  assert(defined(invoker.max_vms),
         "\"max_vms\" must be defined for ${target_name}.")

  defines = ""
  cflags = "-fno-stack-protector -fno-builtin -ffreestanding -fpic"
  ldflags = "--defsym=ORIGIN_ADDRESS=${invoker.origin_address}"
  if (defined(invoker.extra_defines)) {
    defines += " ${invoker.extra_defines}"
  }
  if (defined(invoker.extra_cflags)) {
    cflags += " ${invoker.extra_cflags}"
  }
  if (defined(invoker.extra_ldflags)) {
    ldflags += " ${invoker.extra_ldflags}"
  }

  embedded_clang_toolchain("${target_name}_clang") {
    target = invoker.target
    tool_prefix = invoker.tool_prefix
    extra_defines = defines
    extra_cflags = cflags
    extra_ldflags = ldflags
    toolchain_args = {
      use_platform = true
      plat_name = invoker.target_name
      plat_arch = invoker.arch
      plat_max_cpus = invoker.max_cpus
      plat_max_vms = invoker.max_vms
      if (defined(invoker.toolchain_args)) {
        forward_variables_from(invoker.toolchain_args, "*")
      }
    }
  }

  embedded_gcc_toolchain("${target_name}_gcc") {
    tool_prefix = invoker.tool_prefix
    extra_defines = defines
    extra_cflags = cflags
    extra_ldflags = ldflags
    toolchain_args = {
      use_platform = true
      plat_name = invoker.target_name
      plat_arch = invoker.arch
      plat_max_cpus = invoker.max_cpus
      plat_max_vms = invoker.max_vms
      if (defined(invoker.toolchain_args)) {
        forward_variables_from(invoker.toolchain_args, "*")
      }
    }
  }
}

# Specialize for different architectures.

template("aarch64_toolchain") {
  assert(defined(invoker.cpu), "\"cpu\" must be defiend for ${target_name}.")
  assert(defined(invoker.origin_address),
         "\"origin_address\" must be defined for ${target_name}.")
  assert(defined(invoker.use_pl011),
         "\"use_pl011\" must be defined for ${target_name}.")
  assert(defined(invoker.max_cpus),
         "\"max_cpus\" must be defined for ${target_name}.")
  assert(defined(invoker.max_vms),
         "\"max_vms\" must be defined for ${target_name}.")

  embedded_platform_toolchain(target_name) {
    forward_variables_from(invoker,
                           [
                             "origin_address",
                             "max_cpus",
                             "max_vms",
                           ])
    arch = "aarch64"
    target = "aarch64-none-eabi"
    tool_prefix = "aarch64-linux-gnu-"  # TODO: this isn't right for bare metal but it works.
    extra_cflags = "-mcpu=${invoker.cpu} -mstrict-align"

    if (invoker.use_pl011) {
      assert(defined(invoker.pl011_base_address),
             "\"pl011_base_address\" must be defined for ${target_name}.")
      extra_defines = "-DPL011_BASE=${invoker.pl011_base_address}"
    }

    toolchain_args = {
      arch_aarch64_use_pl011 = invoker.use_pl011
    }
  }
}