# 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.

import("//build/arch/common.gni")

# Build image, link to an ELF file then convert to plain binary.
template("image_binary") {
  assert(defined(invoker.image_name),
         "image_binary() must specify an \"image_name\" value")
  assert(defined(invoker.origin_address),
         "image_binary() must specify an \"origin_address\" value")

  output_root = ""
  if (defined(invoker.output_path)) {
    output_root += "${invoker.output_path}/"
  }
  output_root += invoker.image_name

  # Link objects together
  executable("${target_name}__elf") {
    forward_variables_from(invoker,
                           [
                             "cflags",
                             "cflags_c",
                             "defines",
                             "deps",
                             "public_deps",
                             "sources",
                             "testonly",
                           ])
    output_name = "${output_root}.elf"
    inputs = [
      rebase_path("//build/image/image.ld"),
    ]
    ldflags = [
      "-pie",
      "-T",
      rebase_path("//build/image/image.ld"),
      "--defsym=ORIGIN_ADDRESS=${invoker.origin_address}",
    ]
    visibility = [ ":${invoker.target_name}" ]
  }

  action(target_name) {
    forward_variables_from(invoker, [ "testonly" ])

    file_root = "${root_out_dir}/${output_root}"
    elf_file = "${file_root}.elf"
    bin_file = "${file_root}.bin"

    script = "//build/image/convert_to_binary.py"
    deps = [
      ":${target_name}__elf",
    ]
    args = [
      "--tool_prefix",
      arch_tool_prefix,
      "--input",
      rebase_path(elf_file),
      "--output",
      rebase_path(bin_file),
    ]
    outputs = [
      bin_file,
    ]
  }
}

# Helper to build a hypervisor image
template("hypervisor") {
  image_binary(target_name) {
    forward_variables_from(invoker,
                           [
                             "cflags",
                             "cflags_c",
                             "defines",
                             "deps",
                             "public_deps",
                             "sources",
                             "testonly",
                           ])
    image_name = target_name
    origin_address = arch_hypervisor_origin_address
  }
}

# Helper to build a virtual machine kernel
template("vm_kernel") {
  image_binary(target_name) {
    forward_variables_from(invoker,
                           [
                             "cflags",
                             "cflags_c",
                             "defines",
                             "deps",
                             "public_deps",
                             "sources",
                             "testonly",
                           ])
    output_path = "vm"
    image_name = target_name
    origin_address = "0x1000"
  }
}

# Build the initial RAM disk for the hypervisor.
template("initrd") {
  assert(defined(invoker.primary_vm),
         "initrd() must specify a \"primary_vm\" value")

  action(target_name) {
    forward_variables_from(invoker, [ "testonly" ])
    script = "//build/image/generate_initrd.py"

    initrd_base = "${root_out_dir}/initrd/${target_name}"
    initrd_file = "${initrd_base}.img"
    initrd_staging = "${initrd_base}"
    vm_dir = rebase_path("${root_out_dir}/vm/")

    deps = [
      invoker.primary_vm,
    ]

    args = [
      "--primary_vm",
      vm_dir + get_label_info(invoker.primary_vm, "name") + ".bin",
      "--staging",
      rebase_path(initrd_staging),
      "--output",
      rebase_path(initrd_file),
    ]

    # Add the info about the secondary VMs. The information about the VMs is
    # encoded in lists with the following elements:
    #
    #    1. Memory in bytes.
    #    2. Number of cores.
    #    3. File name for the VM image.
    #    4. Build target for the VM.
    #
    # TODO: is there a less hacky way to do this?
    if (defined(invoker.secondary_vms)) {
      foreach(vm, invoker.secondary_vms) {
        args += [ "--secondary_vm" ]

        # This is a hack to find the field which names the build target for the
        # VM so it can be added to the dependencies and the image path be
        # passed to the script. The target will be a path or have a semicolon
        # so getting the label name will yield a diferent value. The other
        # fields are simple text so won't change.
        foreach(field, vm) {
          if (get_label_info(field, "name") != field) {
            deps += [ field ]
            args += [ vm_dir + get_label_info(field, "name") + ".bin" ]
          } else {
            args += [ field ]
          }
        }
      }
    }

    outputs = [
      initrd_file,
      "${initrd_staging}/vms.txt",
    ]
  }
}