# Copyright 2011-2024 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(CheckLinkerFlag)

# These affect ABI and linking, so set them globally, even for dependencies
set(CMAKE_CXX_STANDARD_REQUIRED TRUE)
set(CMAKE_CXX_STANDARD 17)
set(CMAKE_CXX_EXTENSIONS FALSE)

set(CMAKE_SKIP_BUILD_RPATH TRUE)
set(CMAKE_POSITION_INDEPENDENT_CODE TRUE)

# Enforce static linkage
set(CMAKE_FIND_LIBRARY_SUFFIXES ${CMAKE_STATIC_LIBRARY_SUFFIX})

if(CMAKE_CXX_COMPILER_ID STREQUAL "GNU")  # GCC
elseif(CMAKE_CXX_COMPILER_ID MATCHES "Clang")  # Clang or Apple Clang
  add_compile_options(
    -Wno-nullability-completeness
    -Wno-invalid-noreturn
  )
elseif(MSVC)  # Visual Studio
  add_compile_options(
    /wd4018  # signed/unsigned mismatch
    /wd4244  # 'argument' conversion, possible loss of data
    /wd4267  # 'initializing' conversion, possible loss of data
  )
  # Use the static runtime
  set(CMAKE_MSVC_RUNTIME_LIBRARY "MultiThreaded$<$<CONFIG:Debug>:Debug>")
else()
  message(FATAL_ERROR "Unsupported compiler")
endif()

if(UNIX)
  add_compile_options(-Wno-deprecated)
  if(APPLE)
    add_compile_options(-gfull)
    add_link_options(
      -dead_strip
    )

    # Work around assertion failure with LTO symbols
    # https://developer.apple.com/documentation/xcode-release-notes/xcode-15-release-notes#Linking
    check_linker_flag(CXX "LINKER:-ld_classic" _binexport_ld_classic_supported)
    if(_binexport_ld_classic_supported)
      add_link_options(LINKER:-ld_classic)
    endif()

    # Suppress ranlib warnings "file has no symbols"
    set(CMAKE_C_ARCHIVE_CREATE
        "<CMAKE_AR> Scr <TARGET> <LINK_FLAGS> <OBJECTS>")
    set(CMAKE_CXX_ARCHIVE_CREATE
        "<CMAKE_AR> Scr <TARGET> <LINK_FLAGS> <OBJECTS>")
    set(CMAKE_C_ARCHIVE_FINISH
        "<CMAKE_RANLIB> -no_warning_for_no_symbols -c <TARGET>")
    set(CMAKE_CXX_ARCHIVE_FINISH
        "<CMAKE_RANLIB> -no_warning_for_no_symbols -c <TARGET>")
  else()
   add_compile_options(
     -ffunction-sections
     -fdata-sections
   )
   add_link_options(LINKER:-gc-sections)
  endif()
elseif(WIN32)
  add_definitions(
    -D_CRT_SECURE_NO_WARNINGS
    # Protobuf iterators trigger deprecation warnings
    -D_SILENCE_ALL_CXX17_DEPRECATION_WARNINGS
    # Do not define min/max macros which collide with std::min()/std::max()
    -DNOMINMAX
    -DWIN32_LEAN_AND_MEAN
  )
endif()