Binary compatibility loss regarding errno

Jakub Jelinek jakub@redhat.com
Sun Dec 29 11:47:00 GMT 2002


On Fri, Dec 27, 2002 at 01:47:45PM -0800, Roland McGrath wrote:
Content-Description: message body text
> > On Fri, Dec 27, 2002 at 01:09:48PM -0800, Roland McGrath wrote:
> > > I consider this an ld bug.  It's invalid to produce other than an
> > > R_386_GLOB_DAT reloc for a data object that is exported at runtime.
> > 
> > If you have a small testcase, I will take a look.
> 
> $ gcc -shared -o loser.so loser.c -Wl,--version-script=loser.v
> $ readelf -r loser.so
> 
> Note no reloc using the symbol `x'.
> 

Content-Description: C source file for ld bug test case
> int x;
> asm(".symver x,x@VERS_1");
> int foo() { return x; }

Content-Description: version script for ld bug test case
> VERS_1 {
>   x; foo;
> };

One more point to the testcase. At least it should be
int x __attribute__((section (".bss")));
- COMMON symbols cannot have aliases (although it is not
diagnosed by assembler). If there are:
     x: 00000004     4 OBJECT  GLOBAL DEFAULT  COM x
     y: 00000004     4 OBJECT  GLOBAL DEFAULT  COM x@VERS_1
symbols in ET_REL object, they mean different objects,
not the same one. glibc is already doing this with errno, it
was just missing from the testcase.

	Jakub



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