On Fri, Oct 9, 2009 at 10:12 AM, Joakim Tjernlund <joakim.tjernl...@transmode.se> wrote: >> >> On Fri, Oct 9, 2009 at 9:27 AM, J. William Campbell >> <jwilliamcampb...@comcast.net> wrote: >> > Graeme Russ wrote: >> >> >> >> On Fri, Oct 9, 2009 at 2:58 AM, J. William Campbell >> >> <jwilliamcampb...@comcast.net> wrote: >> >> >> >>> >> >>> Graeme Russ wrote: >> >>> >> >>>> >> >>>> Out of curiosity, I wanted to see just how much of a size penalty I am >> >>>> incurring by using gcc -fpic / ld -pic on my x86 u-boot build. Here are >> >>>> the results (fixed width font will help - its space, not tab, >> >>>> formatted): >> >>>> >> >>>> Section non-reloc reloc >> >>>> --------------------------------------- >> >>>> .text 000118c4 000137fc <- 0x1f38 bytes (~8kB) bigger >> >>>> .rodata 00005bad 000059d0 >> >>>> .interp n/a 00000013 >> >>>> .dynstr n/a 00000648 >> >>>> .hash n/a 00000428 >> >>>> .eh_frame 00003268 000034fc >> >>>> .data 00000a6c 000001dc >> >>>> .data.rel n/a 00000098 >> >>>> .data.rel.ro.local n/a 00000178 >> >>>> .data.rel.local n/a 000007e4 >> >>>> .got 00000000 000001f0 >> >>>> .got.plt n/a 0000000c >> >>>> .rel.got n/a 000003e0 >> >>>> .rel.dyn n/a 00001228 >> >>>> .dynsym n/a 00000850 >> >>>> .dynamic n/a 00000080 >> >>>> .u_boot_cmd 000003c0 000003c0 >> >>>> .bss 00001a34 00001a34 >> >>>> .realmode 00000166 00000166 >> >>>> .bios 0000053e 0000053e >> >>>> ======================================= >> >>>> Total 0001d5dd 00022287 <- 0x4caa bytes (~19kB) bigger >> >>>> >> >>>> Its more than a 16% increase in size!!! >> >>>> >> >>>> .text accounts for a little under half of the total bloat, and of that, >> >>>> the crude dynamic loader accounts for only 341 bytes >> >>>> >> >>>> >> >>> >> >>> Hi Graeme, >> >>> I would be interested in a third option (column), the x86 build with >> >>> just -mrelocateable but NOT -fpic. It will not be definitive because >> >>> there >> >>> will be extra code that references the GOT and missing code to do some of >> >>> the relocation, but it would still be interesting. >> >>> >> >> >> >> x86 does not have -mrelocatable. This is a PPC only option :( >> >> >> > >> > Hi Graeme, >> > You are unfortunately correct. However, I wonder if we can get >> > essentially the same result by executing the final ld step with the >> > --emit-relocs switch included. This may also include some "extra" sections >> > that we would want to strip out, but if it works, it could give all >> > ELF-based systems a way to a relocatable u-boot. >> > >> >> I don't think --emit-relocs is necessary with -pic. I haven't gone through >> all the permutations to see if there is a smaller option, but gcc -fpic and >> ld -pie creates enough information to perform relocation on the x86 >> platform > > Try -fvisibility=hidden
Thanks - Shaved another 2539 bytes off the binary Also found out how to get rid of .eh_frame (crept in when I upgraded to gcc 4.4.1) with -fno-dwarf2-cfi-asm, so that shaves another 13452 bytes Total saving of 15.6k > > Jocke > > Regards, Graeme _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot