# Copyright 2020 The IREE Authors
#
# Licensed under the Apache License v2.0 with LLVM Exceptions.
# See https://llvm.org/LICENSE.txt for license information.
# SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception

include(CMakeParseArguments)

###############################################################################
# Package detection
###############################################################################

# Checks whether the PyYAML package is available. Sets IREE_PYYAML_FOUND to
# ON if so.
function(iree_detect_pyyaml)
  execute_process(
      COMMAND ${Python3_EXECUTABLE} -c "import yaml"
      RESULT_VARIABLE EXIT_CODE
      OUTPUT_QUIET
      ERROR_QUIET
  )
  if(EXIT_CODE)
    message(STATUS "Looking for PyYAML - not found (some features may not be available: install with 'python -m pip install PyYAML' or equiv for your system)")
    set(IREE_PYYAML_FOUND OFF PARENT_SCOPE)
  else()
    message(STATUS "Looking for PyYAML - found")
    set(IREE_PYYAML_FOUND ON PARENT_SCOPE)
  endif()
endfunction()


###############################################################################
# Main user rules
###############################################################################

# iree_pyext_module()
#
# Builds a native python module (.so/.dylib/.pyd).
#
# Parameters:
# NAME: name of target
# MODULE_NAME: Base-name of the module.
# SRCS: List of source files for the library
# DEPS: List of other targets the test python libraries require
# COPTS: List of private compile options
# DEFINES: List of public defines
# INCLUDES: Include directories to add to dependencies
function(iree_pyext_module)
  cmake_parse_arguments(ARG
    ""
    "NAME;MODULE_NAME;UNIX_LINKER_SCRIPT"
    "SRCS;DEPS;COPTS;DEFINES;INCLUDES"
    ${ARGN})

  iree_package_ns(_PACKAGE_NS)
  # Replace dependencies passed by ::name with ::iree::package::name
  list(TRANSFORM ARG_DEPS REPLACE "^::" "${_PACKAGE_NS}::")
  list(TRANSFORM ARG_PYEXT_DEPS REPLACE "^::" "${_PACKAGE_NS}::")
  # Prefix the library with the package name, so we get: iree_package_name.
  iree_package_name(_PACKAGE_NAME)
  set(_NAME "${_PACKAGE_NAME}_${ARG_NAME}")

  pybind11_add_module(
    ${_NAME}
    ${ARG_SRCS}
  )

  # Alias the iree_package_name library to iree::package::name so that we can
  # refer to this target with the namespaced format.
  add_library(${_PACKAGE_NS}::${ARG_NAME} ALIAS ${_NAME})

  target_link_libraries(
    ${_NAME}
    PRIVATE ${ARG_DEPS}
  )

  set_target_properties(
    ${_NAME} PROPERTIES
      OUTPUT_NAME "${ARG_MODULE_NAME}"
  )

  target_include_directories(${_NAME}
  PUBLIC
    "$<BUILD_INTERFACE:${ARG_INCLUDES}>"
  )

  # pybind11 requires both RTTI and Exceptions, and it does not know that
  # we have disabled them globally, so turn them back on. Since this is
  # *the only* place in the codebase where we do this, just inline here.
  # Note that this is playing with fire and the extension code is structured
  # so as not to cause problems with RTTI cross-module issues.
  iree_select_compiler_opts(_RTTI_AND_EXCEPTION_COPTS
    CLANG_OR_GCC
      "-frtti"
      "-fexceptions"
    MSVC_OR_CLANG_CL
      # Configure exception handling for standard C++ behavior.
      # - /EHs enables C++ catch-style exceptions
      # - /EHc breaks unwinding across extern C boundaries, dramatically reducing
      #   unwind table size and associated exception handling overhead as the
      #   compiler can assume no exception will ever be thrown within any function
      #   annotated with extern "C".
      # https://docs.microsoft.com/en-us/cpp/build/reference/eh-exception-handling-model
      "/EHsc"
      # Configure RTTI generation.
      # - /GR - Enable generation of RTTI (default)
      # - /GR- - Disables generation of RTTI
      # https://docs.microsoft.com/en-us/cpp/build/reference/gr-enable-run-time-type-information?view=msvc-160
      "/GR"
  )

  set_property(TARGET ${_NAME} PROPERTY CXX_STANDARD 17)
  set_property(TARGET ${_NAME} PROPERTY CXX_STANDARD_REQUIRED ON)

  target_compile_options(
    ${_NAME} PRIVATE
    ${ARG_COPTS}
    ${IREE_DEFAULT_COPTS}
    ${_RTTI_AND_EXCEPTION_COPTS}
  )

  target_compile_definitions(
    ${_NAME} PUBLIC
    ${ARG_DEFINES}
  )

  # Link flags.
  if(UNIX AND NOT APPLE)  # Apple does not support linker scripts.
    if(ARG_UNIX_LINKER_SCRIPT)
      set_target_properties(${_NAME} PROPERTIES LINK_FLAGS
        "-Wl,--version-script=\"${CMAKE_CURRENT_SOURCE_DIR}/${ARG_UNIX_LINKER_SCRIPT}\"")
    endif()
  endif()
endfunction()

# iree_py_library()
#
# CMake function to imitate Bazel's iree_py_library rule.
#
# Parameters:
# NAME: name of target
# SRCS: List of source files for the library
# DEPS: List of other targets the test python libraries require
# PYEXT_DEPS: List of deps of extensions built with iree_pyext_module
function(iree_py_library)
  cmake_parse_arguments(
    _RULE
    ""
    "NAME"
    "SRCS;DEPS;PYEXT_DEPS"
    ${ARGN}
  )

  iree_package_ns(_PACKAGE_NS)
  # Replace dependencies passed by ::name with ::iree::package::name
  list(TRANSFORM _RULE_DEPS REPLACE "^::" "${_PACKAGE_NS}::")

  iree_package_name(_PACKAGE_NAME)
  set(_NAME "${_PACKAGE_NAME}_${_RULE_NAME}")

  add_custom_target(${_NAME} ALL
    DEPENDS ${_RULE_DEPS}
  )

  # Symlink each file as its own target.
  foreach(_SRC_FILE ${_RULE_SRCS})
    # _SRC_FILE could have other path components in it, so we need to make a
    # directory for it. Ninja does this automatically, but make doesn't. See
    # https://github.com/google/iree/issues/6801
    set(_SRC_BIN_PATH "${CMAKE_CURRENT_BINARY_DIR}/${_SRC_FILE}")
    get_filename_component(_SRC_BIN_DIR "${_SRC_BIN_PATH}" DIRECTORY)
    add_custom_command(
      TARGET ${_NAME}
      COMMAND
        ${CMAKE_COMMAND} -E make_directory "${_SRC_BIN_DIR}"
      COMMAND ${CMAKE_COMMAND} -E create_symlink
        "${CMAKE_CURRENT_SOURCE_DIR}/${_SRC_FILE}" "${_SRC_BIN_PATH}"
      BYPRODUCTS "${_SRC_BIN_PATH}"
    )
  endforeach()

  # Add PYEXT_DEPS if any.
  if(_RULE_PYEXT_DEPS)
    list(TRANSFORM _RULE_PYEXT_DEPS REPLACE "^::" "${_PACKAGE_NS}::")
    add_dependencies(${_NAME} ${_RULE_PYEXT_DEPS})
  endif()
endfunction()

# iree_local_py_test()
#
# CMake function to run python test with provided python package paths.
#
# Parameters:
# NAME: name of test
# SRC: Test source file
# ARGS: Command line arguments to the Python source file.
# LABELS: Additional labels to apply to the test. The package path is added
#     automatically.
# GENERATED_IN_BINARY_DIR: If present, indicates that the srcs have been
#   in the CMAKE_CURRENT_BINARY_DIR.
# PACKAGE_DIRS: Python package paths to be added to PYTHONPATH.
function(iree_local_py_test)
  if(NOT IREE_BUILD_TESTS OR ANDROID OR EMSCRIPTEN)
    return()
  endif()

  cmake_parse_arguments(
    _RULE
    "GENERATED_IN_BINARY_DIR"
    "NAME;SRC"
    "ARGS;LABELS;PACKAGE_DIRS;TIMEOUT"
    ${ARGN}
  )

  # Switch between source and generated tests.
  set(_SRC_DIR "${CMAKE_CURRENT_SOURCE_DIR}")
  if(_RULE_GENERATED_IN_BINARY_DIR)
    set(_SRC_DIR "${CMAKE_CURRENT_BINARY_DIR}")
  endif()

  iree_package_name(_PACKAGE_NAME)
  set(_NAME "${_PACKAGE_NAME}_${_RULE_NAME}")

  iree_package_ns(_PACKAGE_NS)
  string(REPLACE "::" "/" _PACKAGE_PATH ${_PACKAGE_NS})
  set(_NAME_PATH "${_PACKAGE_PATH}/${_RULE_NAME}")
  list(APPEND _RULE_LABELS "${_PACKAGE_PATH}")

  add_test(
    NAME ${_NAME_PATH}
    COMMAND
      "${Python3_EXECUTABLE}"
      "${CMAKE_CURRENT_SOURCE_DIR}/${_RULE_SRC}"
      ${_RULE_ARGS}
  )

  list(APPEND _RULE_PACKAGE_DIRS "$ENV{PYTHONPATH}")
  string(JOIN ":" _PYTHONPATH ${_RULE_PACKAGE_DIRS})

  if (NOT DEFINED _RULE_TIMEOUT)
    set(_RULE_TIMEOUT 60)
  endif()

  set_property(TEST ${_NAME_PATH} PROPERTY LABELS "${_RULE_LABELS}")
  set_property(TEST ${_NAME_PATH} PROPERTY TIMEOUT ${_RULE_ARGS})

  set_property(TEST ${_NAME_PATH} PROPERTY ENVIRONMENT
      "PYTHONPATH=${_PYTHONPATH}"
  )
  iree_configure_test(${_NAME_PATH})

  # TODO(marbre): Find out how to add deps to tests.
  #               Similar to _RULE_DATA in iree_lit_test().
endfunction()

# iree_py_test()
#
# CMake function to imitate Bazel's iree_py_test rule.
#
# Parameters:
# NAME: name of test
# SRCS: Test source file (single file only, despite name)
# ARGS: Command line arguments to the Python source file.
# LABELS: Additional labels to apply to the test. The package path is added
#     automatically.
# GENERATED_IN_BINARY_DIR: If present, indicates that the srcs have been
#   in the CMAKE_CURRENT_BINARY_DIR.
function(iree_py_test)
  cmake_parse_arguments(
    _RULE
    "GENERATED_IN_BINARY_DIR"
    "NAME;SRCS"
    "ARGS;LABELS;TIMEOUT"
    ${ARGN}
  )

  iree_local_py_test(
    NAME
      "${_RULE_NAME}"
    SRC
      "${_RULE_SRCS}"
    ARGS
      ${_RULE_ARGS}
    LABELS
      ${_RULE_LABELS}
    PACKAGE_DIRS
      "${IREE_BINARY_DIR}/compiler/bindings/python"
      "${IREE_BINARY_DIR}/runtime/bindings/python"
    GENERATED_IN_BINARY_DIR
      "${_RULE_GENERATED_IN_BINARY_DIR}"
    TIMEOUT
      ${_RULE_TIMEOUT}
  )
endfunction()