[Bug gas/17712] Invalid relocation record for pe-x86-64 absolute addresses.

[m at rolle dot name]

https://sourceware.org/bugzilla/show_bug.cgi?id=17712

--- Comment #1 from Michael Rolle <m at rolle dot name> ---
Actually, it's worse than that.  Look at the actual code bytes assembled.

Disassembly of section .text:

0000000000000000 <.text>:
   0:   ff d0                   call   rax
   2:   ff d0                   call   rax
   4:   66 ff d0                call   ax
   7:   66 ff d0                call   ax
   a:   66 ff 10                call   WORD PTR [rax]
   d:   ff e0                   jmp    rax
   f:   ff e0                   jmp    rax
  11:   66 ff e0                jmp    ax
  14:   66 ff e0                jmp    ax
  17:   66 ff 20                jmp    WORD PTR [rax]
  1a:   e8 5b 00 10 00          call   10007a <.text+0x10007a>
  1f:   e9 60 00 10 00          jmp    100084 <.text+0x100084>
  24:   ff d0                   call   rax
  26:   ff d0                   call   rax
  28:   66 ff d0                call   ax
  2b:   66 ff d0                call   ax
  2e:   66 ff 10                call   WORD PTR [rax]
  31:   ff e0                   jmp    rax
  33:   ff e0                   jmp    rax
  35:   66 ff e0                jmp    ax
  38:   66 ff e0                jmp    ax
  3b:   66 ff 20                jmp    WORD PTR [rax]
  3e:   e8 7f 00 10 00          call   1000c2 <.text+0x1000c2>
  43:   e9 84 00 10 00          jmp    1000cc <.text+0x1000cc>

Each of the four call and jump instructions has an address of 0x100040 in the
source code.  The displacement in the first instruction, at 1a, is 10005b, so
without relocation, the instruction will call/jump to address 10005b + (RIP =
1f) = 10007a, and this is relative to the .text segment.

Actually, I believe that it is not possible in 64-bit mode to jump to an
absolute address with a displacement, at least on Windows, because the loader
would not have instructions in the image file to perform the relocation at
image load time.  As I recall, the only way to do it is to load the address
into a register and then call/jump with the register as the operand.  Hence, as
should probably be giving an error message for 'jmp 0x100040', at least on
Windows.  Maybe unix/linux can make it work, I don't know.

-- 
You are receiving this mail because:
You are on the CC list for the bug.