Optimization flags

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1

Hi,

I was wondering, where should I put the optimization flags in the MakeFile, when working in C. Do these go under CDEFINES=?

-DNDEBUG -O2 -g0 -s

Thank you for your help :slight_smile:

2

I don’t have the SDK available to me right now, but I remember it being straight forward to find this answer by looking inside the master Makefile that comes with the SDK. All the examples refer to it.

3

Which flag would it be? I'm not too familiar with MakeFiles

#
# CMake include file for Playdate libraries
#

cmake_minimum_required(VERSION 3.19)

set(CMAKE_VERBOSE_MAKEFILE TRUE)

include_directories("${SDK}/C_API")
message(STATUS "SDK Path: " ${SDK})

set(PDC "${SDK}/bin/pdc" -sdkpath "${SDK}")

add_compile_definitions(TARGET_EXTENSION=1)

if (TOOLCHAIN STREQUAL "armgcc")
	# Device-only

	# Glue code
	target_sources(${PLAYDATE_GAME_DEVICE} PRIVATE ${SDK}/C_API/buildsupport/setup.c)

	set(HEAP_SIZE 8388208)
	set(STACK_SIZE 61800)
	set(CMAKE_ASM_FLAGS "${CMAKE_ASM_FLAGS} -x assembler-with-cpp -D__HEAP_SIZE=${HEAP_SIZE} -D__STACK_SIZE=${STACK_SIZE}")

	set(MCFLAGS -mthumb -mcpu=cortex-m7 -mfloat-abi=hard -mfpu=fpv5-sp-d16 -D__FPU_USED=1)

	target_compile_definitions(${PLAYDATE_GAME_DEVICE} PUBLIC TARGET_PLAYDATE=1)
	target_compile_options(${PLAYDATE_GAME_DEVICE} PUBLIC -Wall -Wno-unknown-pragmas -Wdouble-promotion)
	target_compile_options(${PLAYDATE_GAME_DEVICE} PUBLIC $<$<CONFIG:DEBUG>:-O2>)
	target_compile_options(${PLAYDATE_GAME_DEVICE} PUBLIC $<$<CONFIG:RELEASE>:-O2>)

	target_compile_options(${PLAYDATE_GAME_DEVICE} PUBLIC ${MCFLAGS})
	target_compile_options(${PLAYDATE_GAME_DEVICE} PUBLIC -falign-functions=16 -fomit-frame-pointer)
	target_compile_options(${PLAYDATE_GAME_DEVICE} PUBLIC -gdwarf-2)
	target_compile_options(${PLAYDATE_GAME_DEVICE} PUBLIC -fverbose-asm)
	target_compile_options(${PLAYDATE_GAME_DEVICE} PUBLIC -ffunction-sections -fdata-sections)

    target_compile_options(${PLAYDATE_GAME_DEVICE} PUBLIC $<$<COMPILE_LANGUAGE:CXX>:-fno-exceptions>)

	target_link_options(${PLAYDATE_GAME_DEVICE} PUBLIC ${MCFLAGS})
	target_link_options(${PLAYDATE_GAME_DEVICE} PUBLIC -T${SDK}/C_API/buildsupport/link_map.ld)
	target_link_options(${PLAYDATE_GAME_DEVICE} PUBLIC "-Wl,-Map=game.map,--cref,--gc-sections,--no-warn-mismatch")

else ()
	# Simulator-only
	target_compile_definitions(${PLAYDATE_GAME_NAME} PUBLIC TARGET_SIMULATOR=1)
	if (MSVC)
		target_compile_definitions(${PLAYDATE_GAME_NAME} PUBLIC _WINDLL=1)
		target_compile_options(${PLAYDATE_GAME_NAME} PUBLIC /W3)
		target_compile_options(${PLAYDATE_GAME_NAME} PUBLIC $<$<CONFIG:DEBUG>:/Od>)
	else()
		target_compile_options(${PLAYDATE_GAME_NAME} PUBLIC -Wall -Wstrict-prototypes -Wno-unknown-pragmas -Wdouble-promotion)
		target_compile_options(${PLAYDATE_GAME_NAME} PUBLIC $<$<CONFIG:DEBUG>:-ggdb -O0>)
	endif()

endif ()
4

check C_FLAGS values in CMakeCache.txt. You'll notice there are multiple as you can switch between debug release etc using cmake. Todo that you just run cmake again with for example -DCMAKE_BUILD_TYPE=Release

5

The file you want is sdk/C_API/buildsupport/common.mk, and the variable is called CPFLAGS. You should be able to add optimization configs there, but maybe don't remove any of the flags the makefile already defines.

6

@joyrider3774 In the docs:

Building for Release

When you’re ready to do a release build, regenerate the build targets by passing -DCMAKE_BUILD_TYPE=Release argument to CMake.

I'm not familiar with cmake, I'm using a plain MakeFile, is there a way for me to specify making a release build from this?

Edit

I've learnt cmake, made everything a whole lot easier.
Thanks everyone.

2 Likes
7

In answer to the original question, there's no official way of passing compiler arguments from your user Makefile to buildsupport/common.mk. However, there's nothing stoping you from adding them to UDEFS. As previously noted, using CMake is the solution if you want to get fancy.