Re: perl-5.14.4

[Achim Gratz <Stromeko@nexgo.de>]

Corinna Vinschen writes:
>> Back to the drawing board…  The section names in rebase are completely
>> different,
>
> "completely different"?  -v, please?

I gave up in disgust… anyway, instead of the .debug_* section names,
rebase finds something like "/19".  I can't find a way to have objdump
use the same format.  Objcopy does have an option that hints at some
"long section names" that can be present and I surmise that the debug
sections use such names.

>> not sure how I should get objdump to display them.
>
> objdump -h?

Nope.  That tells you:

Sections:
Idx Name          Size      VMA               LMA               File off  Algn
  0 .text         00000b98  00000003e5411000  00000003e5411000  00000600  2**4
                  CONTENTS, ALLOC, LOAD, READONLY, CODE, DATA
  1 .data         00000068  00000003e5412000  00000003e5412000  00001200  2**5
                  CONTENTS, ALLOC, LOAD, DATA
  2 .rdata        00003800  00000003e5413000  00000003e5413000  00001400  2**6
                  CONTENTS, ALLOC, LOAD, READONLY, DATA
  3 .buildid      00000035  00000003e5417000  00000003e5417000  00004c00  2**2
                  CONTENTS, ALLOC, LOAD, READONLY, DATA
  4 .pdata        000000cc  00000003e5418000  00000003e5418000  00004e00  2**2
                  CONTENTS, ALLOC, LOAD, READONLY, DATA
  5 .xdata        0000008c  00000003e5419000  00000003e5419000  00005000  2**2
                  CONTENTS, ALLOC, LOAD, READONLY, DATA
  6 .bss          000001d0  00000003e541a000  00000003e541a000  00000000  2**5
                  ALLOC
  7 .edata        0000012b  00000003e541b000  00000003e541b000  00005200  2**2
                  CONTENTS, ALLOC, LOAD, READONLY, DATA
  8 .idata        000004fc  00000003e541c000  00000003e541c000  00005400  2**2
                  CONTENTS, ALLOC, LOAD, DATA
  9 .reloc        000006b4  00000003e541d000  00000003e541d000  00005a00  2**2
                  CONTENTS, ALLOC, LOAD, READONLY, DATA
 10 .debug_aranges 00000220  00000003e541e000  00000003e541e000  00006200  2**0
                  CONTENTS, READONLY, DEBUGGING
 11 .debug_info   0000cc86  00000003e541f000  00000003e541f000  00006600  2**0
                  CONTENTS, READONLY, DEBUGGING
 12 .debug_abbrev 00000e74  00000003e542c000  00000003e542c000  00013400  2**0
                  CONTENTS, READONLY, DEBUGGING
 13 .debug_line   00000e93  00000003e542d000  00000003e542d000  00014400  2**0
                  CONTENTS, READONLY, DEBUGGING
 14 .debug_frame  00000350  00000003e542e000  00000003e542e000  00015400  2**3
                  CONTENTS, READONLY, DEBUGGING
 15 .debug_loc    00000b22  00000003e5430000  00000003e5430000  00015800  2**0
                  CONTENTS, READONLY, DEBUGGING
 16 .debug_ranges 000000c0  00000003e5431000  00000003e5431000  00016400  2**0
                  CONTENTS, READONLY, DEBUGGING
 17 .debug_str    000001a8  0000000400000000  0000000400000000  00016600  2**0
                  CONTENTS, READONLY, DEBUGGING

While rebase thinks:

Base:       0x0x2f0000
ImageBase:  0x3e2660000
ImageBase: 0x3e2660000 ImageSize: 0x22000
   section name:    .text base: 0x00001000 size: 0x00000c00 file offset: 0x00000600 offset: 0x002ef600
   section name:    .data base: 0x00002000 size: 0x00000200 file offset: 0x00001200 offset: 0x002ef200
   section name:   .rdata base: 0x00003000 size: 0x00003800 file offset: 0x00001400 offset: 0x002ee400
   section name: .buildid base: 0x00007000 size: 0x00000200 file offset: 0x00004c00 offset: 0x002edc00
   section name:   .pdata base: 0x00008000 size: 0x00000200 file offset: 0x00004e00 offset: 0x002ece00
   section name:   .xdata base: 0x00009000 size: 0x00000200 file offset: 0x00005000 offset: 0x002ec000
   section name:     .bss base: 0x0000a000 size: 0x00000000 file offset: 0x00000000 offset: 0x002e6000
   section name:   .edata base: 0x0000b000 size: 0x00000200 file offset: 0x00005200 offset: 0x002ea200
   section name:   .idata base: 0x0000c000 size: 0x00000600 file offset: 0x00005400 offset: 0x002e9400
   section name:   .reloc base: 0x0000d000 size: 0x00000800 file offset: 0x00005a00 offset: 0x002e8a00
   section name:       /4 base: 0x0000e000 size: 0x00000400 file offset: 0x00006200 offset: 0x002e8200
   section name:      /19 base: 0x0000f000 size: 0x0000ce00 file offset: 0x00006600 offset: 0x002e7600
   section name:      /31 base: 0x0001c000 size: 0x00001000 file offset: 0x00013400 offset: 0x002e7400
   section name:      /45 base: 0x0001d000 size: 0x00001000 file offset: 0x00014400 offset: 0x002e7400
   section name:      /57 base: 0x0001e000 size: 0x00000400 file offset: 0x00015400 offset: 0x002e7400
   section name:      /70 base: 0x0001f000 size: 0x00000200 file offset: 0x00015800 offset: 0x002e6800
   section name:      /81 base: 0x00020000 size: 0x00000c00 file offset: 0x00015a00 offset: 0x002e5a00
   section name:      /92 base: 0x00021000 size: 0x00000200 file offset: 0x00016600 offset: 0x002e5600

>> Also,
>> rebase does not seem to touch the debug sections in any way (either it
>> does not recognize them or already ignores them).  The apparent changes
>> that I saw in objdump are purely the result of rebase changing the
>> ImageBase.  :-(
>
> So it's not about the debug sections, apparently.  It was just a guess
> anyway.

It still is about the debug sections…  They are still present in the
rebased object files, but nm and objdump don't associate the information
in them with the code anymore.  The same thing already happens when I
just change the ImageBase, so it seems that rebase would somehow also
have to change something in the debug records, albeit it's entirely
unclear what that might be.


Regards,
Achim.
-- 
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