Mercurial > sdl-ios-xcode
view include/SDL_version.h @ 3162:dc1eb82ffdaa
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
author | Sam Lantinga <slouken@libsdl.org> |
---|---|
date | Wed, 03 Jun 2009 04:37:27 +0000 |
parents | 972a69e47cd9 |
children | d3baf5ac4e37 |
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/* SDL - Simple DirectMedia Layer Copyright (C) 1997-2009 Sam Lantinga This library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version. This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with this library; if not, write to the Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA Sam Lantinga slouken@libsdl.org */ /** * \file SDL_version.h * * This header defines the current SDL version */ #ifndef _SDL_version_h #define _SDL_version_h #include "SDL_stdinc.h" #include "SDL_revision.h" #include "begin_code.h" /* Set up for C function definitions, even when using C++ */ #ifdef __cplusplus /* *INDENT-OFF* */ extern "C" { /* *INDENT-ON* */ #endif /** * \struct SDL_version * \brief Information the version of SDL in use. * * Represents the library's version as three levels: major revision * (increments with massive changes, additions, and enhancements), * minor revision (increments with backwards-compatible changes to the * major revision), and patchlevel (increments with fixes to the minor * revision). * * \sa SDL_VERSION * \sa SDL_GetVersion */ typedef struct SDL_version { Uint8 major; /**< major version */ Uint8 minor; /**< minor version */ Uint8 patch; /**< update version */ } SDL_version; /* Printable format: "%d.%d.%d", MAJOR, MINOR, PATCHLEVEL */ #define SDL_MAJOR_VERSION 1 #define SDL_MINOR_VERSION 3 #define SDL_PATCHLEVEL 0 /** * \def SDL_VERSION(x) * \brief Macro to determine SDL version program was compiled against. * * This macro fills in a SDL_version structure with the version of the * library you compiled against. This is determined by what header the * compiler uses. Note that if you dynamically linked the library, you might * have a slightly newer or older version at runtime. That version can be * determined with SDL_GetVersion(), which, unlike SDL_VERSION, * is not a macro. * * \param x A pointer to a SDL_version struct to initialize. * * \sa SDL_version * \sa SDL_GetVersion */ #define SDL_VERSION(x) \ { \ (x)->major = SDL_MAJOR_VERSION; \ (x)->minor = SDL_MINOR_VERSION; \ (x)->patch = SDL_PATCHLEVEL; \ } /* This macro turns the version numbers into a numeric value: (1,2,3) -> (1203) This assumes that there will never be more than 100 patchlevels */ #define SDL_VERSIONNUM(X, Y, Z) \ ((X)*1000 + (Y)*100 + (Z)) /* This is the version number macro for the current SDL version */ #define SDL_COMPILEDVERSION \ SDL_VERSIONNUM(SDL_MAJOR_VERSION, SDL_MINOR_VERSION, SDL_PATCHLEVEL) /* This macro will evaluate to true if compiled with SDL at least X.Y.Z */ #define SDL_VERSION_ATLEAST(X, Y, Z) \ (SDL_COMPILEDVERSION >= SDL_VERSIONNUM(X, Y, Z)) /** * \fn void SDL_GetVersion(SDL_version *ver) * \brief Get the version of SDL that is linked against your program. * * If you are using a shared library (DLL) version of SDL, then it is * possible that it will be different than the version you compiled against. * * This is a real function; the macro SDL_VERSION tells you what version * of SDL you compiled against: * * \code * SDL_version compiled; * SDL_version linked; * * SDL_VERSION(&compiled); * SDL_GetVersion(&linked); * printf("We compiled against SDL version %d.%d.%d ...\n", * compiled.major, compiled.minor, compiled.patch); * printf("But we linked against SDL version %d.%d.%d.\n", * linked.major, linked.minor, linked.patch); * \endcode * * This function may be called safely at any time, even before SDL_Init(). * * \sa SDL_VERSION */ extern DECLSPEC void SDLCALL SDL_GetVersion(SDL_version * ver); /** * \fn int SDL_GetRevision(void) * \brief Get the code revision of SDL that is linked against your program. */ extern DECLSPEC int SDLCALL SDL_GetRevision(void); /* Ends C function definitions when using C++ */ #ifdef __cplusplus /* *INDENT-OFF* */ } /* *INDENT-ON* */ #endif #include "close_code.h" #endif /* _SDL_version_h */ /* vi: set ts=4 sw=4 expandtab: */