src/SDL_fatal.c
author Sam Lantinga <slouken@libsdl.org>
Wed, 03 Jun 2009 04:37:27 +0000
changeset 3162 dc1eb82ffdaa
parent 2984 0b160c970b7e
child 3644 09ce26cedfd2
permissions -rw-r--r--
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

/*
    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
*/
#include "SDL_config.h"

/* General fatal signal handling code for SDL */

#ifdef HAVE_SIGNAL_H

#include <signal.h>

#include "SDL_stdinc.h"
#include "SDL_fatal.h"

/* This installs some signal handlers for the more common fatal signals,
   so that if the programmer is lazy, the app doesn't die so horribly if
   the program crashes.
*/

static void
SDL_Parachute(int sig)
{
    signal(sig, SIG_DFL);
    SDL_Quit();
    raise(sig);
}

static const int SDL_fatal_signals[] = {
    SIGSEGV,
#ifdef SIGBUS
    SIGBUS,
#endif
#ifdef SIGFPE
    SIGFPE,
#endif
#ifdef SIGQUIT
    SIGQUIT,
#endif
    0
};

void
SDL_InstallParachute(void)
{
    /* Set a handler for any fatal signal not already handled */
    int i;
#ifdef HAVE_SIGACTION
    struct sigaction action;

    for (i = 0; SDL_fatal_signals[i]; ++i) {
        sigaction(SDL_fatal_signals[i], NULL, &action);
        if (action.sa_handler == SIG_DFL) {
            action.sa_handler = SDL_Parachute;
            sigaction(SDL_fatal_signals[i], &action, NULL);
        }
    }
#ifdef SIGALRM
    /* Set SIGALRM to be ignored -- necessary on Solaris */
    sigaction(SIGALRM, NULL, &action);
    if (action.sa_handler == SIG_DFL) {
        action.sa_handler = SIG_IGN;
        sigaction(SIGALRM, &action, NULL);
    }
#endif
#else
    void (*ohandler) (int);

    for (i = 0; SDL_fatal_signals[i]; ++i) {
        ohandler = signal(SDL_fatal_signals[i], SDL_Parachute);
        if (ohandler != SIG_DFL) {
            signal(SDL_fatal_signals[i], ohandler);
        }
    }
#endif /* HAVE_SIGACTION */
    return;
}

void
SDL_UninstallParachute(void)
{
    /* Remove a handler for any fatal signal handled */
    int i;
#ifdef HAVE_SIGACTION
    struct sigaction action;

    for (i = 0; SDL_fatal_signals[i]; ++i) {
        sigaction(SDL_fatal_signals[i], NULL, &action);
        if (action.sa_handler == SDL_Parachute) {
            action.sa_handler = SIG_DFL;
            sigaction(SDL_fatal_signals[i], &action, NULL);
        }
    }
#else
    void (*ohandler) (int);

    for (i = 0; SDL_fatal_signals[i]; ++i) {
        ohandler = signal(SDL_fatal_signals[i], SIG_DFL);
        if (ohandler != SDL_Parachute) {
            signal(SDL_fatal_signals[i], ohandler);
        }
    }
#endif /* HAVE_SIGACTION */
}

#else

/* No signals on this platform, nothing to do.. */

void
SDL_InstallParachute(void)
{
    return;
}

void
SDL_UninstallParachute(void)
{
    return;
}

#endif /* HAVE_SIGNAL_H */
/* vi: set ts=4 sw=4 expandtab: */