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Re: Binutils objcopy bug (was Re: rebase segfault)
2013/1/25 marco atzeri <marco.atzeri@gmail.com>:
> On 1/24/2013 11:00 AM, Corinna Vinschen wrote:
>
>> I already explained why: The SEGV happens during relocation.
>> The file header has been changed already. If you call the
>> same rebase, it will try to rebase the file to the same new
>> address. If current file base address == requested file base
>> address, rebase will return without performing any action.
>>
>
> Hi Corinna,
> I would like your opinion on this .reloc strange issue of
> dict_snowball, as I have the impression I found the root cause.
>
> The relocation table looks the same for the the build, strip and
> with debug link dll's
>
> $ objdump -p dict_snowball-strip.dll |grep Virtual |wc -l
> 130
>
> $ objdump -p dict_snowball-build.dll |grep Virtual |wc -l
> 130
>
> $ objdump -p dict_snowball-debug.dll |grep Virtual |wc -l
> 130
>
> but some some sections does not exist anymore after the strip,
> so the .reloc table should be smaller after strip.
>
> $ objdump -p dict_snowball-build.dll |grep Virtual
> Virtual Address: 00001000 Chunk size 72 (0x48) Number of fixups 32
>
> [cut]
>
> Virtual Address: 0002e000 Chunk size 340 (0x154) Number of fixups 166
>
> [this area points to the .debug_* sections,
> starting with .debug_info, up to .debug_loc]
>
> Virtual Address: 0003b000 Chunk size 96 (0x60) Number of fixups 44
> Virtual Address: 0003f000 Chunk size 12 (0xc) Number of fixups 2
> ....
> Virtual Address: 00098000 Chunk size 20 (0x14) Number of fixups 6
> Virtual Address: 0009a000 Chunk size 12 (0xc) Number of fixups 2
>
>
> $ objdump -h dict_snowball-build.dll
>
> dict_snowball-build.dll: file format pei-i386
>
> Sections:
> Idx Name Size VMA LMA File off Algn
> 0 .text 00016808 67ec1000 67ec1000 00000400 2**4
> CONTENTS, ALLOC, LOAD, READONLY, CODE, DATA
> 1 .data 00017180 67ed8000 67ed8000 00016e00 2**5
> CONTENTS, ALLOC, LOAD, DATA
> 2 .bss 000000f8 67ef0000 67ef0000 00000000 2**5
> ALLOC
> 3 .edata 00000fe0 67ef1000 67ef1000 0002e000 2**2
> CONTENTS, ALLOC, LOAD, READONLY, DATA
> 4 .idata 000003e0 67ef2000 67ef2000 0002f000 2**2
> CONTENTS, ALLOC, LOAD, DATA
> 5 .reloc 0000765c 67ef3000 67ef3000 0002f400 2**2
> CONTENTS, ALLOC, LOAD, READONLY, DATA
> 6 .debug_aranges 00000560 67efb000 67efb000 00036c00 2**0
> CONTENTS, READONLY, DEBUGGING
> 7 .debug_pubnames 00001112 67efc000 67efc000 00037200 2**0
> CONTENTS, READONLY, DEBUGGING
> 8 .debug_pubtypes 00000f49 67efe000 67efe000 00038400 2**0
> CONTENTS, READONLY, DEBUGGING
> 9 .debug_info 00048851 67eff000 67eff000 00039400 2**0
> CONTENTS, READONLY, DEBUGGING
> 10 .debug_abbrev 000050a3 67f48000 67f48000 00081e00 2**0
> CONTENTS, READONLY, DEBUGGING
> 11 .debug_line 000078a3 67f4e000 67f4e000 00087000 2**0
> CONTENTS, READONLY, DEBUGGING
> 12 .debug_frame 00002114 67f56000 67f56000 0008ea00 2**2
> CONTENTS, READONLY, DEBUGGING
> 13 .debug_str 00000664 67f59000 67f59000 00090c00 2**0
> CONTENTS, READONLY, DEBUGGING
> 14 .debug_loc 000170a4 67f5a000 67f5a000 00091400 2**0
> CONTENTS, READONLY, DEBUGGING
> 15 .debug_ranges 0000f3a0 67f72000 67f72000 000a8600 2**0
> CONTENTS, READONLY, DEBUGGING
>
> $ objdump -h dict_snowball-strip.dll
>
> dict_snowball-strip.dll: file format pei-i386
>
> Sections:
> Idx Name Size VMA LMA File off Algn
> 0 .text 00016808 67ec1000 67ec1000 00000400 2**4
> CONTENTS, ALLOC, LOAD, READONLY, CODE, DATA
> 1 .data 00017180 67ed8000 67ed8000 00016e00 2**5
> CONTENTS, ALLOC, LOAD, DATA
> 2 .bss 000000f8 67ef0000 67ef0000 00000000 2**5
> ALLOC
> 3 .edata 00000fe0 67ef1000 67ef1000 0002e000 2**2
> CONTENTS, ALLOC, LOAD, READONLY, DATA
> 4 .idata 000003e0 67ef2000 67ef2000 0002f000 2**2
> CONTENTS, ALLOC, LOAD, DATA
> 5 .reloc 0000765c 67ef3000 67ef3000 0002f400 2**2
> CONTENTS, ALLOC, LOAD, READONLY, DATA
>
>
> Questions:
> - Is it anomalous to have a .reloc portion addressing the
> debug_* sections (so the original build file is broken)
> - or should strip recognize and remove reloc portion not
> anymore relevant ?
>
> rebase is choking on this portion of the .reloc table
>
>>
>> Corinna
>>
>
> Thansk in advance
> Marco
Well, here are my 2-cents about that issue. In general it is a flaw
to have an base-relocation in debug-section, as this means such a
section can't be moved into a separate debug-file anymore, due that
has no relocation-information.
Nevertheless it would be good, if objcopy gets adjusted to eliminated
base-relocations of stripped sections.
Kai
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