Mercurial > sdl-ios-xcode
view build-scripts/fatbuild.sh @ 4105:84882a89ca50 SDL-1.2
Date: Thu, 27 Dec 2007 07:38:25 +0000
From: John Bartholomew
Subject: [SDL] SDL Semaphore implementation broken on Windows?
Hi,
Over the past couple of days, I've been battling with SDL, SDL_Mixer and SMPEG to try to find an audio hang bug. I believe I've found the problem, which I think is a race condition inside SDL's semaphore implementation (at least the Windows implementation). The semaphore code uses Windows' built in semaphore functions, but it also maintains a separate count value. This count value is updated with bare increment and decrement operations in SemPost and SemWaitTimeout - no locking primitives to protect them.
In tracking down the apparent audio bug, I found that at some point a semaphore's count value was being decremented to -1, which is clearly not a valid value for it to take.
I'm still not certain exactly what sequence of operations is occuring for this to happen, but I believe that overall it's a race condition between a thread calling SemPost (which increments the count) and the thread on the other end calling SemWait (which decrements it).
I will try to make a test case to verify this, but I'm not sure if I'll be able to (threading errors being difficult to reproduce even in the best circumstances).
However, assuming this is the cause of my problems, there is a very
simple fix:
Windows provides InterlockedIncrement() and InterlockedDecrement()
functions to perform increments and decrements which are guaranteed to be atomic. So the fix is in thread/win32/SDL_syssem.c: replace occurrences of --sem->count with InterlockedDecrement(&sem->count); and replace occurrences of ++sem->count with InterlockedIncrement(&sem->count);
This is using SDL v1.2.12, built with VC++ 2008 Express, running on a
Core 2 duo processor.
author | Sam Lantinga <slouken@libsdl.org> |
---|---|
date | Fri, 28 Dec 2007 22:05:17 +0000 |
parents | e3945f84427f |
children | 1bc3d3b2cde1 |
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#!/bin/sh # # Build a fat binary on Mac OS X, thanks Ryan! # Number of CPUs (for make -j) NCPU=`sysctl -n hw.ncpu` NJOB=$NCPU #NJOB=`expr $NCPU + 1` # Generic, cross-platform CFLAGS you always want go here. CFLAGS="-O3 -g -pipe" # PowerPC configure flags (10.3 runtime compatibility) # We dynamically load X11, so using the system X11 headers is fine. CONFIG_PPC="--build=`uname -p`-apple-darwin --host=powerpc-apple-darwin \ --x-includes=/usr/X11R6/include --x-libraries=/usr/X11R6/lib" # PowerPC compiler flags CC_PPC="gcc-4.0 -arch ppc" CXX_PPC="g++-4.0 -arch ppc" CFLAGS_PPC="" CPPFLAGS_PPC="-DMAC_OS_X_VERSION_MIN_REQUIRED=1030 \ -nostdinc \ -F/Developer/SDKs/MacOSX10.3.9.sdk/System/Library/Frameworks \ -I/Developer/SDKs/MacOSX10.3.9.sdk/usr/lib/gcc/powerpc-apple-darwin9/4.0.1/include \ -isystem /Developer/SDKs/MacOSX10.3.9.sdk/usr/include" # PowerPC linker flags LFLAGS_PPC="-arch ppc -mmacosx-version-min=10.3 \ -L/Developer/SDKs/MacOSX10.3.9.sdk/usr/lib/gcc/powerpc-apple-darwin9/4.0.1 \ -F/Developer/SDKs/MacOSX10.3.9.sdk/System/Library/Frameworks \ -Wl,-syslibroot,/Developer/SDKs/MacOSX10.3.9.sdk" # Intel configure flags (10.4 runtime compatibility) # We dynamically load X11, so using the system X11 headers is fine. CONFIG_X86="--build=`uname -p`-apple-darwin --host=i386-apple-darwin \ --x-includes=/usr/X11R6/include --x-libraries=/usr/X11R6/lib" # Intel compiler flags CC_X86="gcc-4.0 -arch i386" CXX_X86="g++-4.0 -arch i386" CFLAGS_X86="-mmacosx-version-min=10.4" CPPFLAGS_X86="-DMAC_OS_X_VERSION_MIN_REQUIRED=1040 \ -nostdinc \ -F/Developer/SDKs/MacOSX10.4u.sdk/System/Library/Frameworks \ -I/Developer/SDKs/MacOSX10.4u.sdk/usr/lib/gcc/i686-apple-darwin9/4.0.1/include \ -isystem /Developer/SDKs/MacOSX10.4u.sdk/usr/include" # Intel linker flags LFLAGS_X86="-arch i386 -mmacosx-version-min=10.4 \ -L/Developer/SDKs/MacOSX10.4u.sdk/usr/lib/gcc/i686-apple-darwin9/4.0.1 \ -Wl,-syslibroot,/Developer/SDKs/MacOSX10.4u.sdk" # # Find the configure script # srcdir=`dirname $0`/.. auxdir=$srcdir/build-scripts cd $srcdir # # Figure out which phase to build: # all, # configure, configure-ppc, configure-x86, # make, make-ppc, make-x86, merge # install # clean if test x"$1" = x; then phase=all else phase="$1" fi case $phase in all) configure_ppc="yes" configure_x86="yes" make_ppc="yes" make_x86="yes" merge="yes" ;; configure) configure_ppc="yes" configure_x86="yes" ;; configure-ppc) configure_ppc="yes" ;; configure-x86) configure_x86="yes" ;; make) make_ppc="yes" make_x86="yes" merge="yes" ;; make-ppc) make_ppc="yes" ;; make-x86) make_x86="yes" ;; merge) merge="yes" ;; install) install_bin="yes" install_hdrs="yes" install_lib="yes" install_data="yes" install_man="yes" ;; install-bin) install_bin="yes" ;; install-hdrs) install_hdrs="yes" ;; install-lib) install_lib="yes" ;; install-data) install_data="yes" ;; install-man) install_man="yes" ;; clean) clean_ppc="yes" clean_x86="yes" ;; clean-ppc) clean_ppc="yes" ;; clean-x86) clean_x86="yes" ;; *) echo "Usage: $0 [all|configure[-ppc|-x86]|make[-ppc|-x86]|merge|install|clean]" exit 1 ;; esac case `uname -p` in powerpc) native_path=ppc ;; *86) native_path=x86 ;; *) echo "Couldn't figure out native architecture path" exit 1 ;; esac # # Create the build directories # for dir in build build/ppc build/x86; do if test -d $dir; then : else mkdir $dir || exit 1 fi done # # Build the PowerPC binary # if test x$configure_ppc = xyes; then (cd build/ppc && \ sh ../../configure $CONFIG_PPC CC="$CC_PPC" CXX="$CXX_PPC" CFLAGS="$CFLAGS $CFLAGS_PPC" CPPFLAGS="$CPPFLAGS_PPC" LDFLAGS="$LFLAGS_PPC") || exit 2 fi if test x$make_ppc = xyes; then (cd build/ppc && ls include && make -j$NJOB) || exit 3 fi # # Build the Intel binary # if test x$configure_x86 = xyes; then (cd build/x86 && \ sh ../../configure $CONFIG_X86 CC="$CC_X86" CXX="$CXX_X86" CFLAGS="$CFLAGS $CFLAGS_X86" CPPFLAGS="$CPPFLAGS_X86" LDFLAGS="$LFLAGS_X86") || exit 2 fi if test x$make_x86 = xyes; then (cd build/x86 && make -j$NJOB) || exit 3 fi # # Combine into fat binary # if test x$merge = xyes; then output=.libs sh $auxdir/mkinstalldirs build/$output cd build target=`find . -mindepth 3 -type f -name '*.dylib' | head -1 | sed 's|.*/||'` (lipo -create -o $output/$target `find . -mindepth 3 -type f -name "*.dylib"` && ln -sf $target $output/libSDL-1.2.0.dylib && ln -sf $target $output/libSDL.dylib && lipo -create -o $output/libSDL.a */build/.libs/libSDL.a && cp $native_path/build/.libs/libSDL.la $output && cp $native_path/build/.libs/libSDL.lai $output && cp $native_path/build/libSDL.la . && lipo -create -o libSDLmain.a */build/libSDLmain.a && echo "Build complete!" && echo "Files can be found in the build directory.") || exit 4 cd .. fi # # Install # do_install() { echo $* $* || exit 5 } if test x$prefix = x; then prefix=/usr/local fi if test x$exec_prefix = x; then exec_prefix=$prefix fi if test x$bindir = x; then bindir=$exec_prefix/bin fi if test x$libdir = x; then libdir=$exec_prefix/lib fi if test x$includedir = x; then includedir=$prefix/include fi if test x$datadir = x; then datadir=$prefix/share fi if test x$mandir = x; then mandir=$prefix/man fi if test x$install_bin = xyes; then do_install sh $auxdir/mkinstalldirs $bindir do_install /usr/bin/install -c -m 755 build/$native_path/sdl-config $bindir/sdl-config fi if test x$install_hdrs = xyes; then do_install sh $auxdir/mkinstalldirs $includedir/SDL for src in $srcdir/include/*.h; do \ file=`echo $src | sed -e 's|^.*/||'`; \ do_install /usr/bin/install -c -m 644 $src $includedir/SDL/$file; \ done do_install /usr/bin/install -c -m 644 $srcdir/include/SDL_config_macosx.h $includedir/SDL/SDL_config.h fi if test x$install_lib = xyes; then do_install sh $auxdir/mkinstalldirs $libdir do_install sh build/$native_path/libtool --mode=install /usr/bin/install -c build/libSDL.la $libdir/libSDL.la do_install /usr/bin/install -c -m 644 build/libSDLmain.a $libdir/libSDLmain.a do_install ranlib $libdir/libSDLmain.a fi if test x$install_data = xyes; then do_install sh $auxdir/mkinstalldirs $datadir/aclocal do_install /usr/bin/install -c -m 644 $srcdir/sdl.m4 $datadir/aclocal/sdl.m4 fi if test x$install_man = xyes; then do_install sh $auxdir/mkinstalldirs $mandir/man3 for src in $srcdir/docs/man3/*.3; do \ file=`echo $src | sed -e 's|^.*/||'`; \ do_install /usr/bin/install -c -m 644 $src $mandir/man3/$file; \ done fi # # Clean up # do_clean() { echo $* $* || exit 6 } if test x$clean_x86 = xyes; then do_clean rm -r build/x86 fi if test x$clean_ppc = xyes; then do_clean rm -r build/ppc fi