Von: Thomas Zimmermann Betreff: [SDL] [PATCH] Make static variables const Datum: Tue, 19 May 2009 19:45:37 +0200 Hi, this is a set of simple changes which make some of SDL's internal static arrays constant. The purpose is to shrink the number of write-able static bytes and thus increase the number of memory pages shared between SDL applications. The patch set is against trunk@4513. Each of the attached patch files is specific to a sub-system. The set is completed by a second mail, because of the list's 40 KiB limit. The files readelf-r4513.txt and readelf-const-patch.txt where made by calling 'readelf -S libSDL.so'. They show the difference in ELF sections without and with the patch. Some numbers measured on my x86-64: Before [13] .rodata PROGBITS 00000000000eaaa0 000eaaa0 0000000000008170 0000000000000000 A 0 0 32 [19] .data.rel.ro PROGBITS 00000000003045e0 001045e0 00000000000023d0 0000000000000000 WA 0 0 32 [23] .data PROGBITS 00000000003076e0 001076e0 0000000000004988 0000000000000000 WA 0 0 32 After [13] .rodata PROGBITS 00000000000eaaa0 000eaaa0 0000000000009a50 0000000000000000 A 0 0 32 [19] .data.rel.ro PROGBITS 0000000000306040 00106040 0000000000002608 0000000000000000 WA 0 0 32 [23] .data PROGBITS 0000000000309360 00109360 0000000000002e88 0000000000000000 WA 0 0 32 The size of the write-able data section decreased considerably. Some entries became const-after-relocation, while most of its content went straight into the read-only data section. Best regards, Thomas

# Makefile to build the SDL library

INCLUDE = -I./include
CFLAGS  = -g -O2 $(INCLUDE)
AR	= ar
RANLIB	= ranlib

CONFIG_H = include/SDL_config.h
TARGET  = libSDL.a
SOURCES = \
	src/*.c \
	src/audio/*.c \
	src/cdrom/*.c \
	src/cpuinfo/*.c \
	src/events/*.c \
	src/file/*.c \
	src/joystick/*.c \
	src/haptic/*.c \
	src/stdlib/*.c \
	src/thread/*.c \
	src/timer/*.c \
	src/video/*.c \
	src/audio/dummy/*.c \
	src/video/dummy/*.c \
	src/joystick/dummy/*.c \
	src/haptic/dummy/*.c \
	src/cdrom/dummy/*.c \
	src/thread/generic/*.c \
	src/timer/dummy/*.c \
	src/loadso/dummy/*.c \

OBJECTS = $(shell echo $(SOURCES) | sed -e 's,\.c,\.o,g')

all: $(TARGET)

$(TARGET): $(CONFIG_H) $(OBJECTS)
	$(AR) crv $@ $^
	$(RANLIB) $@

$(CONFIG_H):
	cp $(CONFIG_H).default $(CONFIG_H)

clean:
	rm -f $(TARGET) $(OBJECTS)