# Copyright 2019 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.

include(CMakeParseArguments)

# iree_bytecode_module()
#
# CMake function to imitate Bazel's iree_bytecode_module rule.
#
# Parameters:
# NAME: Name of target (see Note).
# SRC: Source file to compile into a bytecode module.
# FLAGS: Flags to pass to the translation tool (list of strings). The
#     default flag set is "-iree-mlir-to-vm-bytecode-module".
# TRANSLATE_TOOL: Translation tool to invoke (CMake target). The default
#     tool is "iree-translate".
# CC_NAMESPACE: Wraps everything in a C++ namespace.
# PUBLIC: Add this so that this library will be exported under ${PACKAGE}::
#     Also in IDE, target will appear in ${PACKAGE} folder while non PUBLIC
#     will be in ${PACKAGE}/internal.
# TESTONLY: When added, this target will only be built if user passes
#    -DIREE_BUILD_TESTS=ON to CMake.
#
# Note:
# By default, iree_bytecode_module will create a library named ${NAME}_cc,
# and alias target iree::${NAME}_cc. The iree:: form should always be used.
# This is to reduce namespace pollution.
function(iree_bytecode_module)
  cmake_parse_arguments(
    _RULE
    "PUBLIC;TESTONLY"
    "NAME;SRC;TRANSLATE_TOOL;CC_NAMESPACE"
    "FLAGS"
    ${ARGN}
  )

  if(_RULE_TESTONLY AND NOT IREE_BUILD_TESTS)
    return()
  endif()

  # Set defaults for FLAGS and TRANSLATE_TOOL
  if(DEFINED _RULE_FLAGS)
    set(_FLAGS ${_RULE_FLAGS})
  else()
    set(_FLAGS "-iree-mlir-to-vm-bytecode-module")
  endif()
  if(DEFINED _RULE_TRANSLATE_TOOL)
    set(_TRANSLATE_TOOL ${_RULE_TRANSLATE_TOOL})
  else()
    set(_TRANSLATE_TOOL "iree-translate")
  endif()

  iree_get_executable_path(_TRANSLATE_TOOL_EXECUTABLE ${_TRANSLATE_TOOL})

  set(_ARGS "${_FLAGS}")
  list(APPEND _ARGS "${CMAKE_CURRENT_SOURCE_DIR}/${_RULE_SRC}")
  list(APPEND _ARGS "-o")
  list(APPEND _ARGS "${_RULE_NAME}.vmfb")

  # Depending on the binary instead of the target here given we might not have
  # a target in this CMake invocation when cross-compiling.
  add_custom_command(
    OUTPUT "${_RULE_NAME}.vmfb"
    COMMAND ${_TRANSLATE_TOOL_EXECUTABLE} ${_ARGS}
    # Changes to either the translation tool or the input source should
    # trigger rebuilding.
    DEPENDS ${_TRANSLATE_TOOL_EXECUTABLE} ${_RULE_SRC}
  )

  if(_RULE_TESTONLY)
    set(_TESTONLY_ARG "TESTONLY")
  endif()
  if(_RULE_PUBLIC)
    set(_PUBLIC_ARG "PUBLIC")
  endif()

  if(DEFINED _RULE_CC_NAMESPACE)
    iree_cc_embed_data(
      NAME
        "${_RULE_NAME}_cc"
      IDENTIFIER
        "${_RULE_NAME}"
      GENERATED_SRCS
        "${_RULE_NAME}.vmfb"
      CC_FILE_OUTPUT
        "${_RULE_NAME}.cc"
      H_FILE_OUTPUT
        "${_RULE_NAME}.h"
      CPP_NAMESPACE
        "${_RULE_CC_NAMESPACE}"
      FLATTEN
      "${_PUBLIC_ARG}"
      "${_TESTONLY_ARG}"
    )
  endif()
endfunction()