From:	Mat Hostetter <iclone!mjhostet AT cs DOT unm DOT edu>
Date:	Thu, 20 May 93 06:09:57 -0600
To:	djgpp AT sun DOT soe DOT clarkson DOT edu
Subject:	Followup to cross-linking problems
Cc:	ctm AT cs DOT unm DOT edu

We've spent a lot of time recently looking into why our cross-linker  
(binutils 2.2 ld) generates executables that crash when we try to  
stat.  As a sanity check, I built the old ld that comes with djgpp on  
an i386 Unix box and it allows me to cross-link successfully.

I've noticed two interesting differences between the behavior of the  
binutils 2.2 ld and the one shipped with djgpp:

1) The binutils ld rounds etext up to the nearest 0x400000 byte  
boundary, while the djgpp ld rounds it up to the nearest 0x1000 (page  
size).  I fixed this in the binutils ld, but it didn't solve my  
problem.
2) The djgpp ld generates "V" symbol table entries for __CTOR_LIST__  
and __DTOR_LIST__.  The binutils ld doesn't.  I pored over the  
binutils ld code, and it looks like it can't generate this type of  
symbol, although the appropriate macros are defined.  I don't know  
how important this is.  Various binutils-2.2 utilities (e.g. nm)  
abort() when run on files with "V" entries.

Here is an interesting discrepancy between the cross-linked program  
and the same program linked with djgpp:

< == cross linked, > == djgpp:

< 00000000 A __DYNAMIC
11,16c6,7
< 004001c8 D ___CTOR_LIST__
< 00001170 t ___CTOR_LIST__
< 004001d4 D ___CTOR_LIST__$e
< 004001d4 D ___DTOR_LIST__
< 00001168 t ___DTOR_LIST__
< 004001e0 D ___DTOR_LIST__$e
---
> 004001d4 V ___CTOR_LIST__
> 004001c8 V ___DTOR_LIST__

Does this look glaringly wrong to anyone?


For reference, here is the C program that crashes go32 when  
cross-linked, but works when it's not:

#include <sys/stat.h>

int
main (int argc, char *argv[])
{
  struct stat s;
  stat ("/", &s);
  return 0;
}


I will send uuencoded copies of the good and/or the bad executables  
to anyone who wants them.

-Mat

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