[Bug gas/22874] GAS does not emit multibyte nops before a function symbol

[mliska at suse dot cz]

https://sourceware.org/bugzilla/show_bug.cgi?id=22874

--- Comment #4 from Martin Liska <mliska at suse dot cz> ---
(In reply to H.J. Lu from comment #1)
> The limit of multibyte nop for code alignment is
> 
> #define MAX_MEM_FOR_RS_ALIGN_CODE  31

Thanks, I can confirm that:

00000000004004c0 <foo>:
  4004c0:       eb fe                   jmp    4004c0 <foo>
  4004c2:       66 2e 0f 1f 84 00 00    nopw   %cs:0x0(%rax,%rax,1)
  4004c9:       00 00 00 
  4004cc:       66 2e 0f 1f 84 00 00    nopw   %cs:0x0(%rax,%rax,1)
  4004d3:       00 00 00 
  4004d6:       66 2e 0f 1f 84 00 00    nopw   %cs:0x0(%rax,%rax,1)
  4004dd:       00 00 00 

00000000004004e0 <foo2>:
  4004e0:       f3 c3                   repz retq 
  4004e2:       66 2e 0f 1f 84 00 00    nopw   %cs:0x0(%rax,%rax,1)
  4004e9:       00 00 00 
  4004ec:       0f 1f 40 00             nopl   0x0(%rax)

So the logical question is why is it limited? Does it have any disadvantages to
emit also big paddings in between symbols?

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