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Rockbox mail archiveSubject: Re: Segfault with Faster MDCT patch and -fPICRe: Segfault with Faster MDCT patch and -fPIC
From: Dave Hooper <dave_at_beermex.com>
Date: Fri, 17 Sep 2010 19:01:20 +0100 I think it's hard to tell - let's see what happens without optimisations (-O0) since the code won't always align easily to the source otherwise. > On Fri, 17 Sep 2010 16:26:31 +0200 > Slawomir Testowy <slawomir.testowy_at_gmail.com> wrote: > >> 2010/9/17 Rafaël Carré <rafael.carre_at_gmail.com>: >> > On Fri, 17 Sep 2010 14:01:48 +0200 >> > Slawomir Testowy <slawomir.testowy_at_gmail.com> wrote: >> > >> >> Hi, >> >> >> >> thanks for quick response. >> >> >> >> 2010/9/17 Rafaël Carré <rafael.carre_at_gmail.com>: >> >> > I think the OP should post .S output of gcc and also give >> >> > us compiler version and options being used >> >> > >> >> > -- >> >> > Rafaël Carré >> >> > >> >> >> >> Here it is: >> >> >> >> /opt/freescale/usr/local/gcc-4.1.2-glibc-2.5-nptl-3/arm-none-linux-gnue >> >> abi/bin/arm-none-linux-gnueabi-gcc --version >> >> arm-none-linux-gnueabi-gcc (GCC) 4.1.2 >> >> Copyright (C) 2006 Free Software Foundation, Inc. >> >> This is free software; see the source for copying conditions. >> >> There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR >> >> A PARTICULAR PURPOSE. >> >> >> >> Exact command line: >> >> >> >> /opt/freescale/usr/local/gcc-4.1.2-glibc-2.5-nptl-3/arm-none-linux-gnue >> >> abi/bin/arm-none-linux-gnueabi-gcc -std=gnu89 -fPIC -DHAVE_CONFIG_H >> >> -I. -I./ -O2 -D_ARM_ASSEM_ -fsigned-char -ffast-math >> >> -fsingle-precision-constant -D_REENTRANT -DUSE_MEMORY_H -MT >> >> fft-ffmpeg.lo -MD -MP -MF .deps/fft-ffmpeg.Tpo -c fft-ffmpeg.c -o >> >> fft-ffmpeg.o >> >> >> >> Outputs of gcc -S and gcc -E are included in attachments. >> >> >> >> I'm afraid I won't be able to test proposed patch today. I'll try >> >> on Monday. >> > >> > I think the patch wouldn't compile on ARM because I missed the ldmia >> > ordering constraints like Dave mentioned >> > >> > otherwise I see that fft8_dispatch only differs on 1 register (-fPIC >> > use r9 and without it uses r10==sl) but I don't see r10/sl being >> > used as a pointer.. perhaps it's only done at linking phase? >> > >> > BTW building gdb should be as simple as: >> > ./configure --target=arm-none-linux-gnueabi ; make >> > >> > -- >> > Rafaël Carré >> > >> >> I managed to build gdbserver + gdb. Here is the stacktrace: >> >> Program received signal SIGSEGV, Segmentation fault. >> 0x0003b3a0 in pass (z_arg=<value optimized out>, >> STEP_arg=<value optimized out>, n_arg=<value optimized out>) >> at fft-ffmpeg.c:243 >> 243 w += STEP; >> (gdb) bt >> #0 0x0003b3a0 in pass (z_arg=<value optimized out>, >> STEP_arg=<value optimized out>, n_arg=<value optimized out>) >> at fft-ffmpeg.c:243 >> #1 0x0003c080 in fft64 (z=0x1b10190) at fft-ffmpeg.c:355 >> #2 0x0003c0b0 in fft128 (z=0x1b10190) at fft-ffmpeg.c:356 >> #3 0x0003c0e0 in fft256 (z=0x1b10190) at fft-ffmpeg.c:357 >> #4 0x0003b924 in ff_fft_calc_c (nbits=<value optimized out>, >> z=0x1ae2dc0) at fft-ffmpeg.c:370 >> #5 0x0003ad78 in ff_imdct_half (nbits=28199880, output=0x1b100c8, >> input=<value optimized out>) at mdct-ffmpeg.c:112 >> #6 0x0003b178 in ff_imdct_calc (nbits=28377488, output=0x1afa5c8, >> input=0x0) at mdct-ffmpeg.c:348 >> #7 0x0003a5ac in mapping0_inverse (vb=0xbef3c670, l=0x1b0b538) >> at mapping0.c:290 >> #8 0x00033270 in vorbis_synthesis (vb=0xbef3c670, op=<value >> optimized out>, decodep=1) at synthesis.c:75 >> >> Unfortunately, most values are optimized out. On Monday, I will >> rebuild tremor with -O0 and try again. > > 'info all-registers' + 'disass $pc-32 $pc+32' can give a hint also > (from http://ffmpeg.org/bugreports.html) > > btw you mentioned TRANSFORM_EQUAL (only used in fft8) in your first mail > but this time it's in a different function, a different crash? > > -- > Rafaël Carré Received on 2010-09-17 Page template was last modified "Tue Sep 7 00:00:02 2021" The Rockbox Crew -- Privacy Policy |