From: Mark Eichin <eichin@cygnus>
Date: Sat, 12 Mar 1994 05:37:38 +0000 (+0000)
Subject: Changes to 68k-lynx to make it handle symbols in common sections "properly",
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=f71481ba84d627cb3177ec2dccd68408618cd0b7;p=binutils-gdb.git

Changes to 68k-lynx to make it handle symbols in common sections "properly",
ie. the way "real" 68k coff implementations seem to do it, rather than like
the way it's traditionally done. Fixes lifted from the i386-coff version.
---

diff --git a/bfd/cf-m68klynx.c b/bfd/cf-m68klynx.c
index be52e41777d..f056503940b 100644
--- a/bfd/cf-m68klynx.c
+++ b/bfd/cf-m68klynx.c
@@ -25,6 +25,146 @@ Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.  */
 
 #define COFF_LONG_FILENAMES
 
-#define ONLY_DECLARE_RELOCS
+#define _bfd_m68kcoff_howto_table _bfd_m68klynx_howto_table	
+#define _bfd_m68kcoff_rtype2howto _bfd_m68klynx_rtype2howto	
+#define _bfd_m68kcoff_howto2rtype _bfd_m68klynx_howto2rtype	
+
+#define LYNX_SPECIAL_FN _bfd_m68klynx_special_fn
+
+#include "bfd.h"
+
+static bfd_reloc_status_type _bfd_m68klynx_special_fn PARAMS ((bfd *abfd,
+						      arelent *reloc_entry,
+						      asymbol *symbol,
+						      PTR data,
+						      asection *input_section,
+						      bfd *output_bfd,
+						      char **error_message));
+
+/* For some reason when using m68k COFF the value stored in the .text
+   section for a reference to a common symbol is the value itself plus
+   any desired offset.  (taken from work done by Ian Taylor, Cygnus Support,
+   for I386 COFF).  */
+
+/* If we are producing relocateable output, we need to do some
+   adjustments to the object file that are not done by the
+   bfd_perform_relocation function.  This function is called by every
+   reloc type to make any required adjustments.  */
+
+static bfd_reloc_status_type
+_bfd_m68klynx_special_fn (abfd, reloc_entry, symbol, data, input_section, output_bfd,
+			  error_message)
+     bfd *abfd;
+     arelent *reloc_entry;
+     asymbol *symbol;
+     PTR data;
+     asection *input_section;
+     bfd *output_bfd;
+     char **error_message;
+{
+  symvalue diff;
+
+  if (output_bfd == (bfd *) NULL)
+    return bfd_reloc_continue;
+
+  if (bfd_is_com_section (symbol->section))
+    {
+      /* We are relocating a common symbol.  The current value in the
+	 object file is ORIG + OFFSET, where ORIG is the value of the
+	 common symbol as seen by the object file when it was compiled
+	 (this may be zero if the symbol was undefined) and OFFSET is
+	 the offset into the common symbol (normally zero, but may be
+	 non-zero when referring to a field in a common structure).
+	 ORIG is the negative of reloc_entry->addend, which is set by
+	 the CALC_ADDEND macro below.  We want to replace the value in
+	 the object file with NEW + OFFSET, where NEW is the value of
+	 the common symbol which we are going to put in the final
+	 object file.  NEW is symbol->value.  */
+      diff = symbol->value + reloc_entry->addend;
+    }
+  else
+    {
+      /* For some reason bfd_perform_relocation always effectively
+	 ignores the addend for a COFF target when producing
+	 relocateable output.  This seems to be always wrong for 386
+	 COFF, so we handle the addend here instead.  */
+      diff = reloc_entry->addend;
+    }
+
+#define DOIT(x) \
+  x = ((x & ~howto->dst_mask) | (((x & howto->src_mask) + diff) & howto->dst_mask))
+
+  if (diff != 0)
+    {
+      const reloc_howto_type *howto = reloc_entry->howto;
+      unsigned char *addr = (unsigned char *) data + reloc_entry->address;
+
+      switch (howto->size)
+	{
+	case 0:
+	  {
+	    char x = bfd_get_8 (abfd, addr);
+	    DOIT (x);
+	    bfd_put_8 (abfd, x, addr);
+	  }
+	  break;
+
+	case 1:
+	  {
+	    short x = bfd_get_16 (abfd, addr);
+	    DOIT (x);
+	    bfd_put_16 (abfd, x, addr);
+	  }
+	  break;
+
+	case 2:
+	  {
+	    long x = bfd_get_32 (abfd, addr);
+	    DOIT (x);
+	    bfd_put_32 (abfd, x, addr);
+	  }
+	  break;
+
+	default:
+	  abort ();
+	}
+    }
+
+  /* Now let bfd_perform_relocation finish everything up.  */
+  return bfd_reloc_continue;
+}
+/* Compute the addend of a reloc.  If the reloc is to a common symbol,
+   the object file contains the value of the common symbol.  By the
+   time this is called, the linker may be using a different symbol
+   from a different object file with a different value.  Therefore, we
+   hack wildly to locate the original symbol from this file so that we
+   can make the correct adjustment.  This macro sets coffsym to the
+   symbol from the original file, and uses it to set the addend value
+   correctly.  If this is not a common symbol, the usual addend
+   calculation is done, except that an additional tweak is needed for
+   PC relative relocs.
+   FIXME: This macro refers to symbols and asect; these are from the
+   calling function, not the macro arguments.  */
+
+#define CALC_ADDEND(abfd, ptr, reloc, cache_ptr)		\
+  {								\
+    coff_symbol_type *coffsym = (coff_symbol_type *) NULL;	\
+    if (ptr && bfd_asymbol_bfd (ptr) != abfd)			\
+      coffsym = (obj_symbols (abfd)				\
+	         + (cache_ptr->sym_ptr_ptr - symbols));		\
+    else if (ptr)						\
+      coffsym = coff_symbol_from (abfd, ptr);			\
+    if (coffsym != (coff_symbol_type *) NULL			\
+	&& coffsym->native->u.syment.n_scnum == 0)		\
+      cache_ptr->addend = - coffsym->native->u.syment.n_value;	\
+    else if (ptr && bfd_asymbol_bfd (ptr) == abfd		\
+	     && ptr->section != (asection *) NULL)		\
+      cache_ptr->addend = - (ptr->section->vma + ptr->value);	\
+    else							\
+      cache_ptr->addend = 0;					\
+    if (ptr && howto_table[reloc.r_type].pc_relative)		\
+      cache_ptr->addend += asect->vma;				\
+  }
+
 
 #include "coff-m68k.c"