MIPS/ELF linker

[Ralf Baechle <ralf@gnu.org>]

Starting to play with the new MIPS backend from CVS:

[ralf@lappi binutils]$ cat x.s 
	.text
	.globl	__start
	.weak	hurz
__start:
	la	$2,hurz
[ralf@lappi binutils]$ mips-linux-as -O3 -KPIC -o x.o x.s 
[ralf@lappi binutils]$ mips-linux-ld -o x x.o
x.o(.text+0x0): undefined reference to `hurz'
mips-linux-ld: x.o: .text+0x0: jump to stub routine which is not jal
mips-linux-ld: final link failed: Bad value
[ralf@lappi binutils]$ 

Misshandling error the weak undefined reference prevents any linking
against GNU libc since crti.o has a weak undefined reference against
__gmon_start__.  A fix for elf32-mips.c is appended below.

The ``jump to stub routine which is not jal'' error message which is
obviously bogus as well is caused by mips_elf_calculate_relocation
returning without setting *require_jalxp to a defined value.  A patch
to initialize the variable at the beginning of the function is also
part of the elf32-mips.c patch below.

A third bug is triggered by attempting to link an arbitrary program like
``main(){}'' against glibc 2.0.  This results in a large number of

  /usr/bin/mips-linux-ld: not enough GOT space for local GOT entries

messages.  Obviously the calculation of the GOT size is wrong, but I'm
not yet shure what's the problem, so I just report this without a fix.

Bug #4:

[ralf@lappi bfd]$ cat y.s 
	.text
foo:	la	$2,foo
[ralf@lappi bfd]$ mips-linux-as -O3 -KPIC -o y.o y.s
[ralf@lappi bfd]$ mips-linux-ld -o y y.o
Segmentation fault (core dumped)
[ralf@lappi bfd]$ 

This is caused by g->global_gotsym in elf32-mips.c:7896

       i = elf_hash_table (info)->dynsymcount - g->global_gotsym->dynindx;

being NULL;  I also don't have a fix for this one.

  Ralf

--- elf32-mips.c-cygnus	Sat Jul 31 12:23:43 1999
+++ elf32-mips.c	Sat Jul 31 23:02:33 1999
@@ -5791,6 +5791,9 @@
   /* Assume that there will be no overflow.  */
   overflowed_p = false;
 
+  /* Assume no jalx is required  */
+  *require_jalxp = false;
+
   /* Figure out whether or not the symbol is local, and get the offset
      used in the array of hash table entries.  */
   symtab_hdr = &elf_tdata (input_bfd)->symtab_hdr;
@@ -5870,6 +5873,12 @@
 	  else
 	    symbol = h->root.root.u.def.value;
 	}
+      else if ((h->root.root.type == bfd_link_hash_undefweak)
+               || (info->shared && !info->symbolic && !info->no_undefined))
+        {
+          sec = bfd_und_section_ptr;
+          symbol = 0;
+        }
       else
 	{
 	  (*info->callbacks->undefined_symbol)