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[PATCH] PR ld/19636: [x86] Resolve undefweak and defined symbols in executable

Michael Matz matz@suse.de
Wed Feb 24 14:45:00 GMT 2016 
Hi,

On Tue, 23 Feb 2016, H.J. Lu wrote:

> For i386 and x86-64, undefined weak and defined symbols are resolved
> without dynamic relocation when creating executable.  Undefined weak
> symbols aren't needed in the dynamic symbol table in executable.  One
> exception is on i386, we need undefined weak symbols in the dynamic
> symbol table in PIE if input relocatable files contain branchs without
> PLT so that we can branch to 0 with dynamic relocation in text section.

Um, wait.  Have you now changed it so that this program won't work anymore 
(no matter if PIC or non-PIC)?:

  extern void undef() __attribute__((weak));
  int main()
  {
    if (undef)
      undef ();
    return 0;
  }

> This makes behaviors of static excutable, dynamic excutable and position 
> independent executable consistent with references to undefined weak and 
> defined symbols, regardless if the relocatable input is compiled with 
> PIC or not.

Because, while consistence is good, it's more important that the above 
program keeps working (and if only under PIC).


Ciao,
Michael.
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