[Bug ld/27425] New: erroneous __ImageBase relocation using Microsoft COFF .OBJ linked to .ELF x86_64

[minnowware at hotmail dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=27425

            Bug ID: 27425
           Summary: erroneous __ImageBase relocation using Microsoft COFF
                    .OBJ linked to .ELF x86_64
           Product: binutils
           Version: 2.36
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: ld
          Assignee: unassigned at sourceware dot org
          Reporter: minnowware at hotmail dot com
  Target Milestone: ---

Hi H.J.

there are two (2) more bugs related closely to
https://sourceware.org/bugzilla/show_bug.cgi?id=26583 and
https://sourceware.org/bugzilla/show_bug.cgi?id=27171.

Microsoft COFF x86-64 introduces the "__ImageBase" relative addressing method.
In the .OBJ file a new relocation type is used: IMAGE_REL_AMD64_ADDR32NB.

Please find my comprehensive description here:

https://github.com/KilianKegel/GNU-ld-for-MicrosoftCOFF-to-LinuxELF#__imagebase-bugs

This is mishandled in 2 ways

1a. the 32Bit field ADDR32NB is a DISPLACEMENT only field, but initialized by 
    GNU ld with data offset + 64Bit __executable_start address
1b. the base address address register involved in this addressing scheme is
    initialized to ZERO instead to __executable_start / __ImageBase

https://github.com/KilianKegel/GNU-ld-for-MicrosoftCOFF-to-LinuxELF#addr32nb-initialization-w-__imagebase

2. the symbol addresses taken for __ImageBase addressing scheme are wrong.
   EIP relative addresses taken from the same section instead are correct.

https://github.com/KilianKegel/GNU-ld-for-MicrosoftCOFF-to-LinuxELF#addr32nb-offset-miscalculation

I would really appreciate if you could fix this issue. 

Best regards,
Kilian

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