[PATCH v2 2/2] coff-go32: support extended relocations

This patch extends the relocation and line number counters for
coff-go32 and coff-go32-exe to 32 bits.  As I understand it works the
same as for PE-COFF:

If the number of relocations in an object file exceeds 65534, the
NRELOC field is set to 65535 and the actual number of relocations is
stored in the VADDR field of the first relocation entry.

Executable files have no relocations, and thus the NRELOC field is
repurposed to extend NLNNO to 32-bits.

bfd	* coff-go32.c (COFF_GO32, IMAGE_SCN_LNK_NRELOC_OVFL)
	(coff_SWAP_scnhdr_in, coff_SWAP_scnhdr_out): Define.
	(_bfd_go32_swap_scnhdr_in, _bfd_go32_swap_scnhdr_out)
	(_bfd_go32_mkobject): New functions.
	* coff-stgo32.c (IMAGE_SCN_LNK_NRELOC_OVFL)
	(coff_SWAP_scnhdr_in, coff_SWAP_scnhdr_out): Define.
	(go32exe_mkobject): Call _bfd_go32_mkobject.
	* coffcode.h (COFF_WITH_EXTENDED_RELOC_COUNTER): Define.
	(coff_set_alignment_hook): Define function for COFF_GO32_EXE
	and COFF_GO32.
	(coff_write_relocs): Enable extended reloc counter code if
	COFF_WITH_EXTENDED_RELOC_COUNTER is defined.  Test for obj_go32.
	(coff_write_object_contents): Likewise.  Pad section headers
	for COFF_GO32 and COFF_GO32EXE.  Use bfd_coff_swap_scnhdr_out
	instead of coff_swap_scnhdr_out.
	* cofflink.c (_bfd_coff_final_link): Test also for obj_go32 to
	enable extended reloc counter.
	* coffswap.h: (coff_swap_scnhdr_in, coff_swap_scnhdr_out):
	Declare with ATTRIBUTE_UNUSED.
	* libcoff-in.h: (struct coff_tdata): New field go32.
	(obj_go32): Define.
	* libcoff.h: Regenerate.

1 files changed, 62 insertions, 8 deletions

diff --git a/bfd/coffcode.h b/bfd/coffcode.h
index 3bee5d2..c6569ec 100644
--- a/bfd/coffcode.h
+++ b/bfd/coffcode.h
@@ -364,6 +364,10 @@ CODE_FRAGMENT
 #define GNU_LINKONCE_WT ".gnu.linkonce.wt."
 #define DOT_RELOC	".reloc"
 
+#if defined(COFF_WITH_PE) || defined(COFF_GO32_EXE) || defined(COFF_GO32)
+# define COFF_WITH_EXTENDED_RELOC_COUNTER
+#endif
+
 #if defined (COFF_LONG_SECTION_NAMES)
 /* Needed to expand the inputs to BLANKOR1TOODD.  */
 #define COFFLONGSECTIONCATHELPER(x,y)    x ## y
@@ -1964,6 +1968,39 @@ coff_set_alignment_hook (bfd *abfd, asection *section, void * scnhdr)
 }
 
 #else /* ! RS6000COFF_C */
+#if defined (COFF_GO32_EXE) || defined (COFF_GO32)
+
+static void
+coff_set_alignment_hook (bfd * abfd, asection * section, void * scnhdr)
+{
+  struct internal_scnhdr *hdr = (struct internal_scnhdr *) scnhdr;
+
+  /* Check for extended relocs.  */
+  if (hdr->s_flags & IMAGE_SCN_LNK_NRELOC_OVFL)
+    {
+      struct external_reloc dst;
+      struct internal_reloc n;
+      const file_ptr oldpos = bfd_tell (abfd);
+      const bfd_size_type relsz = bfd_coff_relsz (abfd);
+
+      if (bfd_seek (abfd, (file_ptr) hdr->s_relptr, 0) != 0)
+	return;
+      if (bfd_bread (& dst, relsz, abfd) != relsz)
+	return;
+
+      coff_swap_reloc_in (abfd, &dst, &n);
+      if (bfd_seek (abfd, oldpos, 0) != 0)
+	return;
+      section->reloc_count = hdr->s_nreloc = n.r_vaddr - 1;
+      section->rel_filepos += relsz;
+    }
+  else if (hdr->s_nreloc == 0xffff)
+    _bfd_error_handler
+      (_("%pB: warning: claims to have 0xffff relocs, without overflow"),
+       abfd);
+}
+
+#else /* ! COFF_GO32_EXE && ! COFF_GO32 */
 
 static void
 coff_set_alignment_hook (bfd *abfd ATTRIBUTE_UNUSED,
@@ -1972,6 +2009,7 @@ coff_set_alignment_hook (bfd *abfd ATTRIBUTE_UNUSED,
 {
 }
 
+#endif /* ! COFF_GO32_EXE && ! COFF_GO32 */
 #endif /* ! RS6000COFF_C */
 #endif /* ! COFF_WITH_PE */
 #endif /* ! COFF_ALIGN_IN_SECTION_HEADER */
@@ -2521,8 +2559,8 @@ coff_write_relocs (bfd * abfd, int first_undef)
       if (bfd_seek (abfd, s->rel_filepos, SEEK_SET) != 0)
 	return FALSE;
 
-#ifdef COFF_WITH_PE
-      if (obj_pe (abfd) && s->reloc_count >= 0xffff)
+#ifdef COFF_WITH_EXTENDED_RELOC_COUNTER
+      if ((obj_pe (abfd) || obj_go32 (abfd)) && s->reloc_count >= 0xffff)
 	{
 	  /* Encode real count here as first reloc.  */
 	  struct internal_reloc n;
@@ -3382,9 +3420,9 @@ coff_write_object_contents (bfd * abfd)
   for (current = abfd->sections; current != NULL; current =
        current->next)
     {
-#ifdef COFF_WITH_PE
+#ifdef COFF_WITH_EXTENDED_RELOC_COUNTER
       /* We store the actual reloc count in the first reloc's addr.  */
-      if (obj_pe (abfd) && current->reloc_count >= 0xffff)
+      if ((obj_pe (abfd) || obj_go32 (abfd)) && current->reloc_count >= 0xffff)
 	reloc_count ++;
 #endif
       reloc_count += current->reloc_count;
@@ -3412,9 +3450,9 @@ coff_write_object_contents (bfd * abfd)
 	{
 	  current->rel_filepos = reloc_base;
 	  reloc_base += current->reloc_count * bfd_coff_relsz (abfd);
-#ifdef COFF_WITH_PE
+#ifdef COFF_WITH_EXTENDED_RELOC_COUNTER
 	  /* Extra reloc to hold real count.  */
-	  if (obj_pe (abfd) && current->reloc_count >= 0xffff)
+	  if ((obj_pe (abfd) || obj_go32 (abfd)) && current->reloc_count >= 0xffff)
 	    reloc_base += bfd_coff_relsz (abfd);
 #endif
 	}
@@ -3615,7 +3653,7 @@ coff_write_object_contents (bfd * abfd)
 	  SCNHDR buff;
 	  bfd_size_type amt = bfd_coff_scnhsz (abfd);
 
-	  if (coff_swap_scnhdr_out (abfd, &section, &buff) == 0
+	  if (bfd_coff_swap_scnhdr_out (abfd, &section, &buff) == 0
 	      || bfd_bwrite (& buff, amt, abfd) != amt)
 	    return FALSE;
 	}
@@ -3741,7 +3779,7 @@ coff_write_object_contents (bfd * abfd)
 	  scnhdr.s_nlnno = current->target_index;
 	  scnhdr.s_flags = STYP_OVRFLO;
 	  amt = bfd_coff_scnhsz (abfd);
-	  if (coff_swap_scnhdr_out (abfd, &scnhdr, &buff) == 0
+	  if (bfd_coff_swap_scnhdr_out (abfd, &scnhdr, &buff) == 0
 	      || bfd_bwrite (& buff, amt, abfd) != amt)
 	    return FALSE;
 	}
@@ -3749,6 +3787,22 @@ coff_write_object_contents (bfd * abfd)
 #endif
 #endif
 
+#if defined (COFF_GO32_EXE) || defined (COFF_GO32)
+  /* Pad section headers.  */
+  if ((abfd->flags & EXEC_P) && abfd->sections != NULL)
+    {
+      file_ptr cur_ptr = scn_base
+			 + abfd->section_count * bfd_coff_scnhsz (abfd);
+      long fill_size = (abfd->sections->filepos - cur_ptr);
+      bfd_byte *b = bfd_zmalloc (fill_size);
+      if (b)
+	{
+	  bfd_bwrite ((PTR)b, fill_size, abfd);
+	  free (b);
+	}
+    }
+#endif
+
   /* OK, now set up the filehdr...  */
 
   /* Don't include the internal abs section in the section count */