Build: Add WITH_OPTIMIZED_BUILD_TOOLS

Enable optimizations on Debug builds for executables used for the build
process (datatoc and glsl_preprocess) and enable unity builds for
shader preprocessing targets.

Debug: From 28.9s to 5.7s
Release: From 4.9s to 3.5s

Pull Request: https://projects.blender.org/blender/blender/pulls/138274

CMakeLists.txt

@@ -302,6 +302,12 @@ Use pre-compiled headers to speed up compilation."
   endif()
 endif()
 
+option(WITH_OPTIMIZED_BUILD_TOOLS "\
+Enable optimizations even on Debug builds for executables used for the build process"
+  ON
+)
+mark_as_advanced(WITH_OPTIMIZED_BUILD_TOOLS)
+
 option(WITH_IK_ITASC "\
 Enable ITASC IK solver (only disable for development & for incompatible C++ compilers)"
   ON
@@ -2757,6 +2763,7 @@ if(FIRST_RUN)
 
   info_cfg_text("Compiler Options:")
   info_cfg_option(WITH_BUILDINFO)
+  info_cfg_option(WITH_OPTIMIZED_BUILD_TOOLS)
 
   info_cfg_text("System Options:")
   info_cfg_option(WITH_INSTALL_PORTABLE)

build_files/cmake/macros.cmake

@@ -1513,3 +1513,15 @@ function(compile_sources_as_cpp
   target_include_directories(${executable} PUBLIC ${INC_GLSL})
   target_compile_definitions(${executable} PRIVATE ${define})
 endfunction()
+
+macro(optimize_debug_target executable)
+  if(WITH_OPTIMIZED_BUILD_TOOLS)
+    if(WIN32)
+      remove_cc_flag(${executable} "/Od" "/RTC1")
+      target_compile_options(${executable} PRIVATE "/Ox")
+      target_compile_definitions(${executable} PRIVATE "_ITERATOR_DEBUG_LEVEL=0")
+    else()
+      target_compile_options(${executable} PRIVATE "-O2")
+    endif()
+  endif()
+endmacro()

source/blender/compositor/CMakeLists.txt

@@ -309,6 +309,7 @@ foreach(GLSL_FILE ${GLSL_SRC})
 endforeach()
 
 blender_add_lib(bf_compositor_shaders "${GLSL_C}" "" "" "")
+blender_set_target_unity_build(bf_compositor_shaders 10)
 
 list(APPEND LIB
   bf_compositor_shaders

source/blender/datatoc/CMakeLists.txt

@@ -11,3 +11,4 @@ set(SRC
 
 # `SRC_DNA_INC` is defined in the parent directory.
 add_executable(datatoc ${SRC})
+optimize_debug_target(datatoc)

source/blender/draw/CMakeLists.txt

@@ -733,6 +733,7 @@ foreach(GLSL_FILE ${GLSL_SRC})
 endforeach()
 
 blender_add_lib(bf_draw_shaders "${GLSL_C}" "" "" "")
+blender_set_target_unity_build(bf_draw_shaders 10)
 
 list(APPEND LIB
   PRIVATE bf::animrig

source/blender/gpu/CMakeLists.txt

@@ -710,6 +710,7 @@ if(WITH_METAL_BACKEND)
 endif()
 
 blender_add_lib(bf_gpu_shaders "${SHADER_C}" "" "" "")
+blender_set_target_unity_build(bf_gpu_shaders 10)
 
 list(APPEND LIB
   bf_gpu_shaders

source/blender/gpu/glsl_preprocess/CMakeLists.txt

@@ -17,3 +17,4 @@ endif()
 
 # `SRC_DNA_INC` is defined in the parent directory.
 add_executable(glsl_preprocess ${SRC})
+optimize_debug_target(glsl_preprocess)