[MPlayer-users] [BUGREPORT] VP6 / NSV
vyslnqaaxytp at spammotel.com
Sun Sep 12 23:57:09 CEST 2004
>>>>> On Sun, 12 Sep 2004 18:36:43 +0200, Reimar Döffinger <Reimar.Doeffinger at stud.uni-karlsruhe.de> said:
>>> First, configure MPlayer as usual without debugging. Then open
>>> config.mak, search for "OPTFLAGS =" and replace the "-O4" in
>>> those flags by "-O4 -g", recompile and try if the problem persists. If
>>> yes, send another bugreport as you now hav proper debugging info.
>> Done, and the problem persists...
>> GDB output attached.
>>> Now do the same again, but instead of replacing "-O4" with "-O4 -g"
>>> replace it by "-O2".
>> That's odd. Changing O4 to O2 seems to solve the problem entirely.
Reimar> That's what I expected.
Reimar> I'd like you to do "gdb mplayer" and on the gdb commandline
Reimar> disassemble extend_stack_for_dll_alloca
Reimar> and post the output here.
Reimar> Please try the attached patch, in case the compiler optimizes a bit too
Reimar> good, declaring volatile should avoid it.
The problem is that extend_stack_for_dll_alloca() gets inlined into
PE_InitDLL(), so the extended stack space is still *above* esp when the DLL
entrypoint is called:
movl 16(%ebp), %eax
subl $131072, %esp // alloca(0x20000)
movl $4660, 16(%esp) // *(int*)mem=0x1234
movl %ecx, (%esp)
movl %eax, 8(%esp)
movl 12(%ebp), %eax
movl %eax, 4(%esp)
call *%edx // call entry
The following patch fixes it for gcc 3.2.2 at least:
--- pe_image.c~ 2002-09-13 20:43:13.000000000 +0100
+++ pe_image.c 2004-09-12 22:53:39.000000000 +0100
@@ -896,7 +896,7 @@
* The extend_stack_for_dll_alloca() routine just preallocates a big chunk
* of memory on the stack, for use by the DLLs alloca routine.
-static void extend_stack_for_dll_alloca(void)
+__attribute_noinline__ static void extend_stack_for_dll_alloca(void)
More information about the MPlayer-users