Modernize CMake build system (#1434)

These changes modernize the CMake build system to (hopefully) match newer best practices

* Library linking is simpler and more automatic because of using imported targets
* Multi-configuration builds should be supported (Ninja Multi-Config, Visual Studio, etc. generators)
* Clean up build options using cmake_dependent_option
* Let CMake do its job in more cases, like finding the math/dl libraries and detecting and enabling LTO support
* Remove platform-specific kludges like the Fedora/flatpak LTO workaround and a bunch of Windows stuff
* Simplify Windows static builds
* Consistent formatting

1 files changed, 43 insertions, 81 deletions

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 60dac08..74aaf42 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1,43 +1,38 @@
-cmake_minimum_required(VERSION 3.13)
+cmake_minimum_required(VERSION 3.15)
 
-include(CheckSymbolExists)
-include(CheckLibraryExists)
-
-cmake_policy(VERSION 3.13)
+cmake_policy(VERSION 3.15)
 if (POLICY CMP0076)
     cmake_policy(SET CMP0076 NEW)
 endif()
 
-set(CMAKE_OSX_DEPLOYMENT_TARGET "10.15" CACHE STRING "Minimum OS X deployment version")
+set(CMAKE_POLICY_DEFAULT_CMP0069 NEW)
 
-project(melonDS CXX)
+set(CMAKE_MODULE_PATH "${CMAKE_SOURCE_DIR}/cmake" ${CMAKE_MODULE_PATH})
+
+project(melonDS
+    VERSION 0.9.4
+    DESCRIPTION "DS emulator, sorta"
+    HOMEPAGE_URL "https://melonds.kuribo64.net"
+    LANGUAGES C CXX)
+
+include(CheckSymbolExists)
+include(CheckLibraryExists)
+include(CMakeDependentOption)
+include(CheckIPOSupported)
+
+set(CMAKE_OSX_DEPLOYMENT_TARGET "10.15" CACHE STRING "Minimum OS X deployment version")
 
 set(CMAKE_C_STANDARD 11)
+set(CMAKE_C_STANDARD_REQUIRED ON)
 set(CMAKE_CXX_STANDARD 17)
+set(CMAKE_CXX_STANDARD_REQUIRED ON)
 set(CMAKE_RUNTIME_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR})
 
-set(MELONDS_VERSION "0.9.4")
-add_compile_definitions(MELONDS_VERSION="${MELONDS_VERSION}")
-string(REPLACE "." ";" VERSION_LIST ${MELONDS_VERSION})
-# For the melon.rc file used on Windows
-list(GET VERSION_LIST 0 MELONDS_VERSION_MAJOR)
-list(GET VERSION_LIST 1 MELONDS_VERSION_MINOR)
-# Check if melonDS version is three digits or two digits
-list(LENGTH VERSION_LIST MELONDS_VER_LEN)
-if (${MELONDS_VER_LEN} GREATER 2) 
-    list(GET VERSION_LIST 2 MELONDS_VERSION_PATCH)
-else()
-    set(MELONDS_VERSION_PATCH 0)
-endif()
-
+add_compile_definitions(MELONDS_VERSION="${melonDS_VERSION}")
 
-check_library_exists(m pow "" LIBM)
-if(LIBM)
-    link_libraries(m)
-endif()
-
-if (NOT CMAKE_BUILD_TYPE)
-    set(CMAKE_BUILD_TYPE Release)
+if(NOT CMAKE_BUILD_TYPE AND NOT CMAKE_CONFIGURATION_TYPES)
+    set(CMAKE_BUILD_TYPE Release CACHE STRING "Choose the type of build." FORCE)
+    set_property(CACHE CMAKE_BUILD_TYPE PROPERTY STRINGS "Debug" "Release" "MinSizeRel" "RelWithDebInfo")
 endif()
 
 function(detect_architecture symbol arch)
@@ -61,74 +56,41 @@ detect_architecture("__i386__" x86)
 detect_architecture("__arm__" ARM)
 detect_architecture("__aarch64__" ARM64)
 
-if (ARCHITECTURE STREQUAL x86_64 OR ARCHITECTURE STREQUAL ARM64)
-	option(ENABLE_JIT "Enable x64 JIT recompiler" ON)
-endif()
-
-if (ENABLE_JIT)
-	add_definitions(-DJIT_ENABLED)
-
-	option(ENABLE_JIT_PROFILING "Enable JIT profiling with VTune" OFF)
+cmake_dependent_option(ENABLE_JIT "Enable JIT recompiler" ON
+    "ARCHITECTURE STREQUAL x86_64 OR ARCHITECTURE STREQUAL ARM64" OFF)
+cmake_dependent_option(ENABLE_JIT_PROFILING "Enable JIT profiling with VTune" OFF "ENABLE_JIT" OFF)
+option(ENABLE_OGLRENDERER "Enable OpenGL renderer" ON)
 
-	if (ENABLE_JIT_PROFILING)
-		include(cmake/FindVTune.cmake)
-		add_definitions(-DJIT_PROFILING_ENABLED)
-	endif()
-endif()
+check_ipo_supported(RESULT IPO_SUPPORTED)
+cmake_dependent_option(ENABLE_LTO_RELEASE "Enable link-time optimizations for release builds" ON "IPO_SUPPORTED" OFF)
+cmake_dependent_option(ENABLE_LTO "Enable link-time optimizations" OFF "IPO_SUPPORTED" OFF)
 
-if (CMAKE_BUILD_TYPE STREQUAL Release)
-	option(ENABLE_LTO "Enable link-time optimization" ON)
-else()
-	option(ENABLE_LTO "Enable link-time optimization" OFF)
+if (ENABLE_LTO_RELEASE)
+    set(CMAKE_INTERPROCEDURAL_OPTIMIZATION_RELEASE TRUE)
 endif()
 
-option(ENABLE_OGLRENDERER "Enable OpenGL renderer" ON)
-
-if (ENABLE_OGLRENDERER)
-    add_definitions(-DOGLRENDERER_ENABLED)
+if (ENABLE_LTO)
+    set(CMAKE_INTERPROCEDURAL_OPTIMIZATION TRUE)
 endif()
 
-if (CMAKE_BUILD_TYPE STREQUAL Debug)
-	add_compile_options(-Og)
-endif()
+set(CMAKE_C_FLAGS_DEBUG "-Og")
+set(CMAKE_CXX_FLAGS_DEBUG "-Og")
+set(CMAKE_C_FLAGS_RELEASE "-O3")
+set(CMAKE_CXX_FLAGS_RELEASE "-O3")
 
-if (CMAKE_BUILD_TYPE STREQUAL Release)
-	add_compile_options(-O3)
-	if (NOT APPLE)
-		add_link_options(-s)
-	endif()
+if (NOT APPLE)
+    set(CMAKE_EXE_LINKER_FLAGS_RELEASE "${CMAKE_EXE_LINKER_FLAGS_RELEASE} -s")
 endif()
 
 if (WIN32)
-	option(BUILD_STATIC "Statically link dependencies" OFF)
+    option(BUILD_STATIC "Statically link dependencies" OFF)
 endif()
 
 if (BUILD_STATIC AND WIN32)
     set(CMAKE_FIND_LIBRARY_SUFFIXES .a)
 endif()
 
-if (ENABLE_LTO)
-	if (WIN32 OR APPLE)
-		add_compile_options(-flto)
-		add_link_options(-flto)
-	else()
-		add_compile_options(-flto -fPIC)
-		add_link_options(-flto -fuse-linker-plugin -pie)
-	endif()
-	if (CMAKE_CXX_COMPILER_ID STREQUAL "GNU")
-		set(CMAKE_AR "gcc-ar")
-		set(CMAKE_RANLIB "gcc-ranlib")
-	elseif (CMAKE_CXX_COMPILER_ID STREQUAL "Clang")
-		find_program(LLD NAMES ld.lld ld64.lld lld-link)
-		if (NOT LLD STREQUAL "LLD-NOTFOUND")
-			add_link_options(-fuse-ld=lld)
-		endif()
-		if (NOT APPLE)
-			set(CMAKE_AR "llvm-ar")
-			set(CMAKE_RANLIB "llvm-ranlib")
-		endif()
-	endif()
-endif()
+set(CMAKE_POSITION_INDEPENDENT_CODE ON)
 
 find_program(CCACHE "ccache")
 if (CCACHE)
@@ -142,5 +104,5 @@ option(BUILD_QT_SDL "Build Qt/SDL frontend" ON)
 add_subdirectory(src)
 
 if (BUILD_QT_SDL)
-	add_subdirectory(src/frontend/qt_sdl)
+    add_subdirectory(src/frontend/qt_sdl)
 endif()