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[PATCH]: Support linker relaxation for 68HC11


Hi!

This patch adds support for linker relaxation for 68HC11.
When the address is within 0..0x0ff, we can use a direct addressing
mode for some instruction and reduce them by having a 1 byte address (instead of 2).
(big portions of code taken from existing targets).

Committed on mainline.

	Stephane

2002-08-14  Stephane Carrez  <stcarrez@nerim.fr>

	* elf32-m68hc11.c (m68hc11_relax_group): New to relax group of
	instructions.
	(m68hc11_direct_relax): New to define table of relaxable instructions.
	(find_relaxable_insn): New, find a relaxable insn.
	(compare_reloc): New to compare two relocs.
	(m68hc11_elf_relax_section): New, relax text sections.
	(m68hc11_elf_relax_delete_bytes): New, delete bytes and adjust branchs.
	(elf32_m68hc11_check_relocs): New function for GC support.
	(elf32_m68hc11_relocate_section): New function for GC support.
	(bfd_elf32_bfd_relax_section): Define to support linker relaxation.
	(elf_backend_check_relocs): Likewise.
	(elf_backend_relocate_section): Likewise.
Index: elf32-m68hc11.c
===================================================================
RCS file: /cvs/src/src/bfd/elf32-m68hc11.c,v
retrieving revision 1.7
diff -u -p -r1.7 elf32-m68hc11.c
--- elf32-m68hc11.c	13 Aug 2002 21:15:47 -0000	1.7
+++ elf32-m68hc11.c	14 Aug 2002 08:10:35 -0000
@@ -21,6 +21,7 @@ Foundation, Inc., 59 Temple Place - Suit
 
 #include "bfd.h"
 #include "sysdep.h"
+#include "bfdlink.h"
 #include "libbfd.h"
 #include "elf-bfd.h"
 #include "elf/m68hc11.h"
@@ -43,6 +44,23 @@ PARAMS ((bfd *abfd, struct bfd_link_info
 static boolean elf32_m68hc11_gc_sweep_hook
 PARAMS ((bfd *abfd, struct bfd_link_info *info,
          asection *sec, const Elf_Internal_Rela *relocs));
+static boolean elf32_m68hc11_check_relocs
+PARAMS ((bfd * abfd, struct bfd_link_info * info,
+         asection * sec, const Elf_Internal_Rela * relocs));
+static boolean elf32_m68hc11_relocate_section
+PARAMS ((bfd *output_bfd, struct bfd_link_info *info,
+         bfd *input_bfd, asection *input_section,
+         bfd_byte *contents, Elf_Internal_Rela *relocs,
+         Elf_Internal_Sym *local_syms, asection **local_sections));
+static boolean m68hc11_elf_relax_section
+  PARAMS ((bfd *, asection *, struct bfd_link_info *, boolean *));
+static void m68hc11_elf_relax_delete_bytes
+PARAMS ((bfd *abfd, asection *sec, bfd_vma addr, int count));
+static void m68hc11_relax_group
+PARAMS ((bfd *abfd, asection *sec, bfd_byte *contents,
+         unsigned value, unsigned long offset, unsigned long end_group));
+static int compare_reloc PARAMS ((const void*, const void*));
+
 
 boolean _bfd_m68hc11_elf_merge_private_bfd_data PARAMS ((bfd*, bfd*));
 boolean _bfd_m68hc11_elf_set_private_flags PARAMS ((bfd*, flagword));
@@ -439,6 +457,1037 @@ elf32_m68hc11_gc_sweep_hook (abfd, info,
   return true;
 }
 
+struct m68hc11_direct_relax 
+{
+  const char *name;
+  unsigned char code;
+  unsigned char direct_code;
+} m68hc11_direct_relax_table[] = {
+  { "adca", 0xB9, 0x99 },
+  { "adcb", 0xF9, 0xD9 },
+  { "adda", 0xBB, 0x9B },
+  { "addb", 0xFB, 0xDB },
+  { "addd", 0xF3, 0xD3 },
+  { "anda", 0xB4, 0x94 },
+  { "andb", 0xF4, 0xD4 },
+  { "cmpa", 0xB1, 0x91 },
+  { "cmpb", 0xF1, 0xD1 },
+  { "cpd",  0xB3, 0x93 },
+  { "cpxy", 0xBC, 0x9C },
+/* { "cpy",  0xBC, 0x9C }, */
+  { "eora", 0xB8, 0x98 },
+  { "eorb", 0xF8, 0xD8 },
+  { "jsr",  0xBD, 0x9D },
+  { "ldaa", 0xB6, 0x96 },
+  { "ldab", 0xF6, 0xD6 },
+  { "ldd",  0xFC, 0xDC },
+  { "lds",  0xBE, 0x9E },
+  { "ldxy", 0xFE, 0xDE },
+  /*  { "ldy",  0xFE, 0xDE },*/
+  { "oraa", 0xBA, 0x9A },
+  { "orab", 0xFA, 0xDA },
+  { "sbca", 0xB2, 0x92 },
+  { "sbcb", 0xF2, 0xD2 },
+  { "staa", 0xB7, 0x97 },
+  { "stab", 0xF7, 0xD7 },
+  { "std",  0xFD, 0xDD },
+  { "sts",  0xBF, 0x9F },
+  { "stxy", 0xFF, 0xDF },
+  /*  { "sty",  0xFF, 0xDF },*/
+  { "suba", 0xB0, 0x90 },
+  { "subb", 0xF0, 0xD0 },
+  { "subd", 0xB3, 0x93 },
+  { 0, 0, 0 }
+};
+
+static struct m68hc11_direct_relax *
+find_relaxable_insn (unsigned char code)
+{
+  int i;
+
+  for (i = 0; m68hc11_direct_relax_table[i].name; i++)
+    if (m68hc11_direct_relax_table[i].code == code)
+      return &m68hc11_direct_relax_table[i];
+
+  return 0;
+}
+
+static int
+compare_reloc (e1, e2)
+     const void *e1;
+     const void *e2;
+{
+  const Elf_Internal_Rela *i1 = (const Elf_Internal_Rela *) e1;
+  const Elf_Internal_Rela *i2 = (const Elf_Internal_Rela *) e2;
+
+  if (i1->r_offset == i2->r_offset)
+    return 0;
+  else
+    return i1->r_offset < i2->r_offset ? -1 : 1;
+}
+
+#define M6811_OP_LDX_IMMEDIATE (0xCE)
+
+static void
+m68hc11_relax_group (abfd, sec, contents, value, offset, end_group)
+     bfd *abfd;
+     asection *sec;
+     bfd_byte *contents;
+     unsigned value;
+     unsigned long offset;
+     unsigned long end_group;
+{
+  unsigned char code;
+  unsigned long start_offset;
+  unsigned long ldx_offset = offset;
+  unsigned long ldx_size;
+  int can_delete_ldx;
+  int relax_ldy = 0;
+
+  /* First instruction of the relax group must be a
+     LDX #value or LDY #value.  If this is not the case,
+     ignore the relax group.  */
+  code = bfd_get_8 (abfd, contents + offset);
+  if (code == 0x18)
+    {
+      relax_ldy++;
+      offset++;
+      code = bfd_get_8 (abfd, contents + offset);
+    }
+  ldx_size = offset - ldx_offset + 3;
+  offset += 3;
+  if (code != M6811_OP_LDX_IMMEDIATE || offset >= end_group)
+    return;
+
+
+  /* We can remove the LDX/LDY only when all bset/brclr instructions
+     of the relax group have been converted to use direct addressing
+     mode.  */
+  can_delete_ldx = 1;
+  while (offset < end_group)
+    {
+      unsigned isize;
+      unsigned new_value;
+      int bset_use_y;
+
+      bset_use_y = 0;
+      start_offset = offset;
+      code = bfd_get_8 (abfd, contents + offset);
+      if (code == 0x18)
+        {
+          bset_use_y++;
+          offset++;
+          code = bfd_get_8 (abfd, contents + offset);
+        }
+
+      /* Check the instruction and translate to use direct addressing mode.  */
+      switch (code)
+        {
+          /* bset */
+        case 0x1C:
+          code = 0x14;
+          isize = 3;
+          break;
+
+          /* brclr */
+        case 0x1F:
+          code = 0x13;
+          isize = 4;
+          break;
+
+          /* brset */
+        case 0x1E:
+          code = 0x12;
+          isize = 4;
+          break;
+
+          /* bclr */
+        case 0x1D:
+          code = 0x15;
+          isize = 3;
+          break;
+
+          /* This instruction is not recognized and we are not
+             at end of the relax group.  Ignore and don't remove
+             the first LDX (we don't know what it is used for...).  */
+        default:
+          return;
+        }
+      new_value = (unsigned) bfd_get_8 (abfd, contents + offset + 1);
+      new_value += value;
+      if ((new_value & 0xff00) == 0 && bset_use_y == relax_ldy)
+        {
+          bfd_put_8 (abfd, code, contents + offset);
+          bfd_put_8 (abfd, new_value, contents + offset + 1);
+          if (start_offset != offset)
+            {
+              m68hc11_elf_relax_delete_bytes (abfd, sec, start_offset,
+                                              offset - start_offset);
+              end_group--;
+            }
+        }
+      else
+        {
+          can_delete_ldx = 0;
+        }
+      offset = start_offset + isize;
+    }
+  if (can_delete_ldx)
+    {
+      /* Remove the move instruction (3 or 4 bytes win).  */
+      m68hc11_elf_relax_delete_bytes (abfd, sec, ldx_offset, ldx_size);
+    }
+}
+
+/* This function handles relaxing for the 68HC11.
+
+   
+	and somewhat more difficult to support.  */
+
+static boolean
+m68hc11_elf_relax_section (abfd, sec, link_info, again)
+     bfd *abfd;
+     asection *sec;
+     struct bfd_link_info *link_info;
+     boolean *again;
+{
+  Elf_Internal_Shdr *symtab_hdr;
+  Elf_Internal_Shdr *shndx_hdr;
+  Elf_Internal_Rela *internal_relocs;
+  Elf_Internal_Rela *free_relocs = NULL;
+  Elf_Internal_Rela *irel, *irelend;
+  bfd_byte *contents = NULL;
+  bfd_byte *free_contents = NULL;
+  Elf32_External_Sym *extsyms = NULL;
+  Elf32_External_Sym *free_extsyms = NULL;
+  Elf_Internal_Rela *prev_insn_branch = NULL;
+  Elf_Internal_Rela *prev_insn_group = NULL;
+  unsigned insn_group_value = 0;
+  Elf_External_Sym_Shndx *shndx_buf = NULL;
+
+  /* Assume nothing changes.  */
+  *again = false;
+
+  /* We don't have to do anything for a relocateable link, if
+     this section does not have relocs, or if this is not a
+     code section.  */
+  if (link_info->relocateable
+      || (sec->flags & SEC_RELOC) == 0
+      || sec->reloc_count == 0
+      || (sec->flags & SEC_CODE) == 0)
+    return true;
+
+  /* If this is the first time we have been called for this section,
+     initialize the cooked size.  */
+  if (sec->_cooked_size == 0)
+    sec->_cooked_size = sec->_raw_size;
+
+  symtab_hdr = &elf_tdata (abfd)->symtab_hdr;
+  shndx_hdr = &elf_tdata (abfd)->symtab_shndx_hdr;
+
+  /* Get a copy of the native relocations.  */
+  internal_relocs = (_bfd_elf32_link_read_relocs
+		     (abfd, sec, (PTR) NULL, (Elf_Internal_Rela *) NULL,
+		      link_info->keep_memory));
+  if (internal_relocs == NULL)
+    goto error_return;
+  if (! link_info->keep_memory)
+    free_relocs = internal_relocs;
+
+  /* Checking for branch relaxation relies on the relocations to
+     be sorted on 'r_offset'.  This is not guaranteed so we must sort.  */
+  qsort (internal_relocs, sec->reloc_count, sizeof (Elf_Internal_Rela),
+         compare_reloc);
+
+  /* Walk through them looking for relaxing opportunities.  */
+  irelend = internal_relocs + sec->reloc_count;
+  for (irel = internal_relocs; irel < irelend; irel++)
+    {
+      bfd_vma symval;
+      bfd_vma value;
+      Elf_Internal_Sym isym;
+
+      /* If this isn't something that can be relaxed, then ignore
+	 this reloc.  */
+      if (ELF32_R_TYPE (irel->r_info) != (int) R_M68HC11_16
+          && ELF32_R_TYPE (irel->r_info) != (int) R_M68HC11_RL_JUMP
+          && ELF32_R_TYPE (irel->r_info) != (int) R_M68HC11_RL_GROUP)
+        {
+          prev_insn_branch = 0;
+          prev_insn_group = 0;
+          continue;
+        }
+
+      /* Get the section contents if we haven't done so already.  */
+      if (contents == NULL)
+	{
+	  /* Get cached copy if it exists.  */
+	  if (elf_section_data (sec)->this_hdr.contents != NULL)
+	    contents = elf_section_data (sec)->this_hdr.contents;
+	  else
+	    {
+	      /* Go get them off disk.  */
+	      contents = (bfd_byte *) bfd_malloc (sec->_raw_size);
+	      if (contents == NULL)
+		goto error_return;
+	      free_contents = contents;
+
+	      if (! bfd_get_section_contents (abfd, sec, contents,
+					      (file_ptr) 0, sec->_raw_size))
+		goto error_return;
+	    }
+	}
+
+      /* Try to eliminate an unconditional 8 bit pc-relative branch
+	 which immediately follows a conditional 8 bit pc-relative
+	 branch around the unconditional branch.
+
+	    original:		new:
+	    bCC lab1		bCC' lab2
+	    bra lab2
+	   lab1:	       lab1:
+
+	 This happens when the bCC can't reach lab2 at assembly time,
+	 but due to other relaxations it can reach at link time.  */
+      if (ELF32_R_TYPE (irel->r_info) == (int) R_M68HC11_RL_JUMP)
+	{
+	  Elf_Internal_Rela *nrel;
+	  unsigned char code;
+          unsigned char roffset;
+
+          prev_insn_branch = 0;
+          prev_insn_group = 0;
+          
+	  /* Do nothing if this reloc is the last byte in the section.  */
+	  if (irel->r_offset == sec->_cooked_size)
+	    continue;
+
+	  /* See if the next instruction is an unconditional pc-relative
+	     branch, more often than not this test will fail, so we
+	     test it first to speed things up.  */
+	  code = bfd_get_8 (abfd, contents + irel->r_offset + 2);
+	  if (code != 0x7e)
+	    continue;
+
+	  /* Also make sure the next relocation applies to the next
+	     instruction and that it's a pc-relative 8 bit branch.  */
+	  nrel = irel + 1;
+	  if (nrel == irelend
+	      || irel->r_offset + 3 != nrel->r_offset
+	      || ELF32_R_TYPE (nrel->r_info) != (int) R_M68HC11_16)
+	    continue;
+
+	  /* Make sure our destination immediately follows the
+	     unconditional branch.  */
+          roffset = bfd_get_8 (abfd, contents + irel->r_offset + 1);
+          if (roffset != 3)
+            continue;
+
+          prev_insn_branch = irel;
+          prev_insn_group = 0;
+          continue;
+        }
+
+      /* Read this BFD's symbols if we haven't done so already.  */
+      if (extsyms == NULL)
+	{
+	  /* Get cached copy if it exists.  */
+	  if (symtab_hdr->contents != NULL)
+	    extsyms = (Elf32_External_Sym *) symtab_hdr->contents;
+	  else
+	    {
+	      /* Go get them off disk.  */
+	      bfd_size_type amt = symtab_hdr->sh_size;
+	      extsyms = (Elf32_External_Sym *) bfd_malloc (amt);
+	      if (extsyms == NULL)
+		goto error_return;
+	      free_extsyms = extsyms;
+	      if (bfd_seek (abfd, symtab_hdr->sh_offset, SEEK_SET) != 0
+		  || bfd_bread ((PTR) extsyms, amt, abfd) != amt)
+		goto error_return;
+	    }
+
+	  if (shndx_hdr->sh_size != 0)
+	    {
+	      bfd_size_type amt;
+
+	      amt = symtab_hdr->sh_info * sizeof (Elf_External_Sym_Shndx);
+	      shndx_buf = (Elf_External_Sym_Shndx *) bfd_malloc (amt);
+	      if (shndx_buf == NULL)
+		goto error_return;
+	      if (bfd_seek (abfd, shndx_hdr->sh_offset, SEEK_SET) != 0
+		  || bfd_bread ((PTR) shndx_buf, amt, abfd) != amt)
+		goto error_return;
+	      shndx_hdr->contents = (PTR) shndx_buf;
+	    }
+	}
+
+      /* Get the value of the symbol referred to by the reloc.  */
+      if (ELF32_R_SYM (irel->r_info) < symtab_hdr->sh_info)
+	{
+	  Elf32_External_Sym *esym;
+	  Elf_External_Sym_Shndx *shndx;
+	  asection *sym_sec;
+
+	  /* A local symbol.  */
+	  esym = extsyms + ELF32_R_SYM (irel->r_info);
+	  shndx = shndx_buf + (shndx_buf ? ELF32_R_SYM (irel->r_info) : 0);
+	  bfd_elf32_swap_symbol_in (abfd, esym, shndx, &isym);
+
+	  sym_sec = bfd_section_from_elf_index (abfd, isym.st_shndx);
+	  symval = (isym.st_value
+		    + sym_sec->output_section->vma
+		    + sym_sec->output_offset);
+	}
+      else
+	{
+	  unsigned long indx;
+	  struct elf_link_hash_entry *h;
+
+	  /* An external symbol.  */
+	  indx = ELF32_R_SYM (irel->r_info) - symtab_hdr->sh_info;
+	  h = elf_sym_hashes (abfd)[indx];
+	  BFD_ASSERT (h != NULL);
+	  if (h->root.type != bfd_link_hash_defined
+	      && h->root.type != bfd_link_hash_defweak)
+	    {
+	      /* This appears to be a reference to an undefined
+                 symbol.  Just ignore it--it will be caught by the
+                 regular reloc processing.  */
+              prev_insn_branch = 0;
+              prev_insn_group = 0;
+	      continue;
+	    }
+
+	  symval = (h->root.u.def.value
+		    + h->root.u.def.section->output_section->vma
+		    + h->root.u.def.section->output_offset);
+	}
+
+      if (ELF32_R_TYPE (irel->r_info) == (int) R_M68HC11_RL_GROUP)
+	{
+          prev_insn_branch = 0;
+          prev_insn_group = 0;
+          
+	  /* Do nothing if this reloc is the last byte in the section.  */
+	  if (irel->r_offset == sec->_cooked_size)
+	    continue;
+
+          prev_insn_group = irel;
+          insn_group_value = isym.st_value;
+          continue;
+        }
+
+      value = symval;
+      /* Try to turn a far branch to a near branch.  */
+      if (ELF32_R_TYPE (irel->r_info) == (int) R_M68HC11_16
+          && prev_insn_branch)
+        {
+          bfd_vma offset;
+          unsigned char code;
+
+          offset = value - (prev_insn_branch->r_offset
+                            + sec->output_section->vma
+                            + sec->output_offset + 2);
+
+          /* If the offset is still out of -128..+127 range,
+             leave that far branch unchanged.  */
+          if ((offset & 0xff80) != 0 && (offset & 0xff80) != 0xff80)
+            {
+              prev_insn_branch = 0;
+              continue;
+            }
+
+          /* Shrink the branch.  */
+          code = bfd_get_8 (abfd, contents + prev_insn_branch->r_offset);
+          if (code == 0x7e)
+            {
+              code = 0x20;
+              bfd_put_8 (abfd, code, contents + prev_insn_branch->r_offset);
+              bfd_put_8 (abfd, offset,
+                         contents + prev_insn_branch->r_offset + 1);
+              irel->r_info = ELF32_R_INFO (ELF32_R_SYM (irel->r_info),
+                                           R_M68HC11_NONE);
+              m68hc11_elf_relax_delete_bytes (abfd, sec,
+                                              irel->r_offset, 1);
+            }
+          else
+            {
+              code ^= 0x1;
+              bfd_put_8 (abfd, code, contents + prev_insn_branch->r_offset);
+              bfd_put_8 (abfd, offset,
+                         contents + prev_insn_branch->r_offset + 1);
+              irel->r_info = ELF32_R_INFO (ELF32_R_SYM (irel->r_info),
+                                           R_M68HC11_NONE);
+              m68hc11_elf_relax_delete_bytes (abfd, sec,
+                                              irel->r_offset - 1, 3);
+            }
+          prev_insn_branch = 0;
+        }
+
+      /* Try to turn a 16 bit address into a 8 bit page0 address.  */
+      else if (ELF32_R_TYPE (irel->r_info) == (int) R_M68HC11_16
+               && (value & 0xff00) == 0)
+	{
+          unsigned char code;
+          unsigned short offset;
+          struct m68hc11_direct_relax *rinfo;
+
+          prev_insn_branch = 0;
+          offset = bfd_get_16 (abfd, contents + irel->r_offset);
+          offset += value;
+          if ((offset & 0xff00) != 0)
+            {
+              prev_insn_group = 0;
+              continue;
+            }
+
+          if (prev_insn_group)
+            {
+              /* Note that we've changed the reldection contents, etc.  */
+              elf_section_data (sec)->relocs = internal_relocs;
+              free_relocs = NULL;
+
+              elf_section_data (sec)->this_hdr.contents = contents;
+              free_contents = NULL;
+
+              symtab_hdr->contents = (bfd_byte *) extsyms;
+              free_extsyms = NULL;
+
+              m68hc11_relax_group (abfd, sec, contents, offset,
+                                   prev_insn_group->r_offset,
+                                   insn_group_value);
+              irel = prev_insn_group;
+              prev_insn_group = 0;
+              irel->r_info = ELF32_R_INFO (ELF32_R_SYM (irel->r_info),
+                                           R_M68HC11_NONE);
+              continue;
+            }
+          
+          /* Get the opcode.  */
+          code = bfd_get_8 (abfd, contents + irel->r_offset - 1);
+          rinfo = find_relaxable_insn (code);
+          if (rinfo == 0)
+            {
+              prev_insn_group = 0;
+              continue;
+            }
+
+          /* Note that we've changed the reldection contents, etc.  */
+          elf_section_data (sec)->relocs = internal_relocs;
+          free_relocs = NULL;
+
+          elf_section_data (sec)->this_hdr.contents = contents;
+          free_contents = NULL;
+
+          symtab_hdr->contents = (bfd_byte *) extsyms;
+          free_extsyms = NULL;
+
+          /* Fix the opcode.  */
+          /* printf ("A relaxable case : 0x%02x (%s)\n",
+             code, rinfo->name); */
+          bfd_put_8 (abfd, rinfo->direct_code,
+                     contents + irel->r_offset - 1);
+
+          /* Delete one byte of data (upper byte of address).  */
+          m68hc11_elf_relax_delete_bytes (abfd, sec, irel->r_offset, 1);
+
+          /* Fix the relocation's type.  */
+          irel->r_info = ELF32_R_INFO (ELF32_R_SYM (irel->r_info),
+                                       R_M68HC11_8);
+
+          /* That will change things, so, we should relax again.
+             Note that this is not required, and it may be slow.  */
+          *again = true;
+        }
+      else if (ELF32_R_TYPE (irel->r_info) == R_M68HC11_16)
+        {
+          unsigned char code;
+          bfd_vma offset;
+
+          prev_insn_branch = 0;
+          code = bfd_get_8 (abfd, contents + irel->r_offset - 1);
+          if (code == 0x7e)
+            {
+              offset = value - (irel->r_offset
+                                + sec->output_section->vma
+                                + sec->output_offset + 1);
+              offset += bfd_get_16 (abfd, contents + irel->r_offset);
+
+              /* If the offset is still out of -128..+127 range,
+                 leave that far branch unchanged.  */
+              if ((offset & 0xff80) == 0 || (offset & 0xff80) == 0xff80)
+                {
+
+                  /* Note that we've changed the reldection contents, etc.  */
+                  elf_section_data (sec)->relocs = internal_relocs;
+                  free_relocs = NULL;
+                  
+                  elf_section_data (sec)->this_hdr.contents = contents;
+                  free_contents = NULL;
+                  
+                  symtab_hdr->contents = (bfd_byte *) extsyms;
+                  free_extsyms = NULL;
+
+                  /* Shrink the branch.  */
+                  code = 0x20;
+                  bfd_put_8 (abfd, code,
+                             contents + irel->r_offset - 1);
+                  bfd_put_8 (abfd, offset,
+                             contents + irel->r_offset);
+                  irel->r_info = ELF32_R_INFO (ELF32_R_SYM (irel->r_info),
+                                               R_M68HC11_NONE);
+                  m68hc11_elf_relax_delete_bytes (abfd, sec,
+                                                  irel->r_offset + 1, 1);
+                }
+            }
+        }
+      prev_insn_branch = 0;
+    }
+
+  if (free_relocs != NULL)
+    {
+      free (free_relocs);
+      free_relocs = NULL;
+    }
+
+  if (free_contents != NULL)
+    {
+      if (! link_info->keep_memory)
+	free (free_contents);
+      else
+	{
+	  /* Cache the section contents for elf_link_input_bfd.  */
+	  elf_section_data (sec)->this_hdr.contents = contents;
+	}
+      free_contents = NULL;
+    }
+
+  if (free_extsyms != NULL)
+    {
+      if (! link_info->keep_memory)
+	free (free_extsyms);
+      else
+	{
+	  /* Cache the symbols for elf_link_input_bfd.  */
+	  symtab_hdr->contents = (unsigned char *) extsyms;
+	}
+      free_extsyms = NULL;
+    }
+
+  return true;
+
+ error_return:
+  if (free_relocs != NULL)
+    free (free_relocs);
+  if (free_contents != NULL)
+    free (free_contents);
+  if (free_extsyms != NULL)
+    free (free_extsyms);
+  return false;
+}
+
+/* Delete some bytes from a section while relaxing.  */
+
+static void
+m68hc11_elf_relax_delete_bytes (abfd, sec, addr, count)
+     bfd *abfd;
+     asection *sec;
+     bfd_vma addr;
+     int count;
+{
+  Elf_Internal_Shdr *symtab_hdr;
+  Elf_Internal_Shdr *shndx_hdr;
+  Elf32_External_Sym *extsyms;
+  unsigned int sec_shndx;
+  Elf_External_Sym_Shndx *shndx;
+  bfd_byte *contents;
+  Elf_Internal_Rela *irel, *irelend;
+  bfd_vma toaddr;
+  Elf32_External_Sym *esym, *esymend;
+  struct elf_link_hash_entry **sym_hashes;
+  struct elf_link_hash_entry **end_hashes;
+  unsigned int symcount;
+
+  symtab_hdr = &elf_tdata (abfd)->symtab_hdr;
+  extsyms = (Elf32_External_Sym *) symtab_hdr->contents;
+
+  sec_shndx = _bfd_elf_section_from_bfd_section (abfd, sec);
+
+  contents = elf_section_data (sec)->this_hdr.contents;
+
+  toaddr = sec->_cooked_size;
+
+  irel = elf_section_data (sec)->relocs;
+  irelend = irel + sec->reloc_count;
+
+  /* Actually delete the bytes.  */
+  memmove (contents + addr, contents + addr + count,
+	   (size_t) (toaddr - addr - count));
+  sec->_cooked_size -= count;
+
+  /* Adjust all the relocs.  */
+  for (irel = elf_section_data (sec)->relocs; irel < irelend; irel++)
+    {
+      unsigned char code;
+      unsigned char offset;
+      unsigned short raddr;
+      unsigned long old_offset;
+      int branch_pos;
+
+      old_offset = irel->r_offset;
+
+      /* See if this reloc was for the bytes we have deleted, in which
+	 case we no longer care about it.  Don't delete relocs which
+	 represent addresses, though.  */
+      if (ELF32_R_TYPE (irel->r_info) != R_M68HC11_RL_JUMP
+          && irel->r_offset >= addr && irel->r_offset < addr + count)
+        irel->r_info = ELF32_R_INFO (ELF32_R_SYM (irel->r_info),
+                                     R_M68HC11_NONE);
+
+      if (ELF32_R_TYPE (irel->r_info) == R_M68HC11_NONE)
+        continue;
+
+      /* Get the new reloc address.  */
+      if ((irel->r_offset > addr
+	   && irel->r_offset < toaddr))
+	irel->r_offset -= count;
+
+      /* If this is a PC relative reloc, see if the range it covers
+         includes the bytes we have deleted.  */
+      switch (ELF32_R_TYPE (irel->r_info))
+	{
+	default:
+	  break;
+
+	case R_M68HC11_RL_JUMP:
+          code = bfd_get_8 (abfd, contents + irel->r_offset);
+          switch (code)
+            {
+              /* jsr and jmp instruction are also marked with RL_JUMP
+                 relocs but no adjustment must be made.  */
+            case 0x7e:
+            case 0x9d:
+            case 0xbd:
+              continue;
+
+            case 0x12:
+            case 0x13:
+              branch_pos = 3;
+              raddr = 4;
+
+              /* Special case when we translate a brclr N,y into brclr *<addr>
+                 In this case, the 0x18 page2 prefix is removed.
+                 The reloc offset is not modified but the instruction
+                 size is reduced by 1.  */
+              if (old_offset == addr)
+                raddr++;
+              break;
+
+            case 0x1e:
+            case 0x1f:
+              branch_pos = 3;
+              raddr = 4;
+              break;
+
+            case 0x18:
+              branch_pos = 4;
+              raddr = 5;
+              break;
+
+            default:
+              branch_pos = 1;
+              raddr = 2;
+              break;
+            }
+          offset = bfd_get_8 (abfd, contents + irel->r_offset + branch_pos);
+          raddr += old_offset;
+          raddr += ((unsigned short) offset | ((offset & 0x80) ? 0xff00 : 0));
+          if (irel->r_offset < addr && raddr >= addr)
+            {
+              offset -= count;
+              bfd_put_8 (abfd, offset, contents + irel->r_offset + branch_pos);
+            }
+          else if (irel->r_offset >= addr && raddr <= addr)
+            {
+              offset += count;
+              bfd_put_8 (abfd, offset, contents + irel->r_offset + branch_pos);
+            }
+          else
+            {
+              /*printf ("Not adjusted 0x%04x [0x%4x 0x%4x]\n", raddr,
+                irel->r_offset, addr);*/
+            }
+          
+          break;
+	}
+    }
+
+  /* Adjust the local symbols defined in this section.  */
+  shndx_hdr = &elf_tdata (abfd)->symtab_shndx_hdr;
+  shndx = (Elf_External_Sym_Shndx *) shndx_hdr->contents;
+  esym = extsyms;
+  esymend = esym + symtab_hdr->sh_info;
+  for (; esym < esymend; esym++, shndx = (shndx ? shndx + 1 : NULL))
+    {
+      Elf_Internal_Sym isym;
+      Elf_External_Sym_Shndx dummy;
+
+      bfd_elf32_swap_symbol_in (abfd, esym, shndx, &isym);
+
+      if (isym.st_shndx == sec_shndx
+	  && isym.st_value > addr
+	  && isym.st_value < toaddr)
+	{
+	  isym.st_value -= count;
+	  bfd_elf32_swap_symbol_out (abfd, &isym, esym, &dummy);
+	}
+    }
+
+  /* Now adjust the global symbols defined in this section.  */
+  symcount = (symtab_hdr->sh_size / sizeof (Elf32_External_Sym)
+	      - symtab_hdr->sh_info);
+  sym_hashes = elf_sym_hashes (abfd);
+  end_hashes = sym_hashes + symcount;
+  for (; sym_hashes < end_hashes; sym_hashes++)
+    {
+      struct elf_link_hash_entry *sym_hash = *sym_hashes;
+      if ((sym_hash->root.type == bfd_link_hash_defined
+	   || sym_hash->root.type == bfd_link_hash_defweak)
+	  && sym_hash->root.u.def.section == sec
+	  && sym_hash->root.u.def.value > addr
+	  && sym_hash->root.u.def.value < toaddr)
+	{
+	  sym_hash->root.u.def.value -= count;
+	}
+    }
+}
+
+/* Look through the relocs for a section during the first phase.
+   Since we don't do .gots or .plts, we just need to consider the
+   virtual table relocs for gc.  */
+
+static boolean
+elf32_m68hc11_check_relocs (abfd, info, sec, relocs)
+     bfd * abfd;
+     struct bfd_link_info * info;
+     asection * sec;
+     const Elf_Internal_Rela * relocs;
+{
+  Elf_Internal_Shdr *           symtab_hdr;
+  struct elf_link_hash_entry ** sym_hashes;
+  struct elf_link_hash_entry ** sym_hashes_end;
+  const Elf_Internal_Rela *     rel;
+  const Elf_Internal_Rela *     rel_end;
+
+  if (info->relocateable)
+    return true;
+
+  symtab_hdr = & elf_tdata (abfd)->symtab_hdr;
+  sym_hashes = elf_sym_hashes (abfd);
+  sym_hashes_end = sym_hashes + symtab_hdr->sh_size / sizeof (Elf32_External_Sym);
+  if (!elf_bad_symtab (abfd))
+    sym_hashes_end -= symtab_hdr->sh_info;
+
+  rel_end = relocs + sec->reloc_count;
+
+  for (rel = relocs; rel < rel_end; rel++)
+    {
+      struct elf_link_hash_entry * h;
+      unsigned long r_symndx;
+
+      r_symndx = ELF32_R_SYM (rel->r_info);
+
+      if (r_symndx < symtab_hdr->sh_info)
+        h = NULL;
+      else
+        h = sym_hashes [r_symndx - symtab_hdr->sh_info];
+
+      switch (ELF32_R_TYPE (rel->r_info))
+        {
+        /* This relocation describes the C++ object vtable hierarchy.
+           Reconstruct it for later use during GC.  */
+        case R_M68HC11_GNU_VTINHERIT:
+          if (!_bfd_elf32_gc_record_vtinherit (abfd, sec, h, rel->r_offset))
+            return false;
+          break;
+
+        /* This relocation describes which C++ vtable entries are actually
+           used.  Record for later use during GC.  */
+        case R_M68HC11_GNU_VTENTRY:
+          if (!_bfd_elf32_gc_record_vtentry (abfd, sec, h, rel->r_addend))
+            return false;
+          break;
+        }
+    }
+
+  return true;
+}
+
+/* Relocate a 68hc11/68hc12 ELF section.  */
+static boolean
+elf32_m68hc11_relocate_section (output_bfd, info, input_bfd, input_section,
+                                contents, relocs, local_syms, local_sections)
+     bfd *output_bfd ATTRIBUTE_UNUSED;
+     struct bfd_link_info *info;
+     bfd *input_bfd;
+     asection *input_section;
+     bfd_byte *contents;
+     Elf_Internal_Rela *relocs;
+     Elf_Internal_Sym *local_syms;
+     asection **local_sections;
+{
+  Elf_Internal_Shdr *symtab_hdr;
+  struct elf_link_hash_entry **sym_hashes;
+  Elf_Internal_Rela *rel, *relend;
+  const char *name;
+
+  symtab_hdr = &elf_tdata (input_bfd)->symtab_hdr;
+  sym_hashes = elf_sym_hashes (input_bfd);
+
+  rel = relocs;
+  relend = relocs + input_section->reloc_count;
+  for (; rel < relend; rel++)
+    {
+      int r_type;
+      reloc_howto_type *howto;
+      unsigned long r_symndx;
+      Elf_Internal_Sym *sym;
+      asection *sec;
+      struct elf_link_hash_entry *h;
+      bfd_vma relocation;
+      bfd_reloc_status_type r;
+
+      r_symndx = ELF32_R_SYM (rel->r_info);
+      r_type = ELF32_R_TYPE (rel->r_info);
+
+      if (r_type == R_M68HC11_GNU_VTENTRY
+          || r_type == R_M68HC11_GNU_VTINHERIT )
+        continue;
+
+      howto = elf_m68hc11_howto_table + r_type;
+
+      if (info->relocateable)
+	{
+	  /* This is a relocateable link.  We don't have to change
+	     anything, unless the reloc is against a section symbol,
+	     in which case we have to adjust according to where the
+	     section symbol winds up in the output section.  */
+	  if (r_symndx < symtab_hdr->sh_info)
+	    {
+	      sym = local_syms + r_symndx;
+	      if (ELF_ST_TYPE (sym->st_info) == STT_SECTION)
+		{
+		  sec = local_sections[r_symndx];
+		  rel->r_addend += sec->output_offset + sym->st_value;
+		}
+	    }
+
+	  continue;
+	}
+
+      /* This is a final link.  */
+      h = NULL;
+      sym = NULL;
+      sec = NULL;
+      if (r_symndx < symtab_hdr->sh_info)
+	{
+	  sym = local_syms + r_symndx;
+	  sec = local_sections[r_symndx];
+	  relocation = (sec->output_section->vma
+			+ sec->output_offset
+			+ sym->st_value);
+	}
+      else
+	{
+	  h = sym_hashes[r_symndx - symtab_hdr->sh_info];
+	  while (h->root.type == bfd_link_hash_indirect
+		 || h->root.type == bfd_link_hash_warning)
+	    h = (struct elf_link_hash_entry *) h->root.u.i.link;
+	  if (h->root.type == bfd_link_hash_defined
+	      || h->root.type == bfd_link_hash_defweak)
+	    {
+	      sec = h->root.u.def.section;
+	      relocation = (h->root.u.def.value
+			    + sec->output_section->vma
+			    + sec->output_offset);
+	    }
+	  else if (h->root.type == bfd_link_hash_undefweak)
+	    relocation = 0;
+	  else
+	    {
+	      if (!((*info->callbacks->undefined_symbol)
+		    (info, h->root.root.string, input_bfd,
+		     input_section, rel->r_offset, true)))
+		return false;
+	      relocation = 0;
+	    }
+	}
+
+      if (h != NULL)
+	name = h->root.root.string;
+      else
+	{
+	  name = (bfd_elf_string_from_elf_section
+		  (input_bfd, symtab_hdr->sh_link, sym->st_name));
+	  if (name == NULL || *name == '\0')
+	    name = bfd_section_name (input_bfd, sec);
+	}
+
+      r = _bfd_final_link_relocate (howto, input_bfd, input_section,
+                                    contents, rel->r_offset,
+                                    relocation, rel->r_addend);
+
+      if (r != bfd_reloc_ok)
+	{
+	  const char * msg = (const char *) 0;
+
+	  switch (r)
+	    {
+	    case bfd_reloc_overflow:
+	      if (!((*info->callbacks->reloc_overflow)
+		    (info, name, howto->name, (bfd_vma) 0,
+		     input_bfd, input_section, rel->r_offset)))
+		return false;
+	      break;
+
+	    case bfd_reloc_undefined:
+	      if (!((*info->callbacks->undefined_symbol)
+		    (info, name, input_bfd, input_section,
+		     rel->r_offset, true)))
+		return false;
+	      break;
+
+	    case bfd_reloc_outofrange:
+	      msg = _ ("internal error: out of range error");
+	      goto common_error;
+
+	    case bfd_reloc_notsupported:
+	      msg = _ ("internal error: unsupported relocation error");
+	      goto common_error;
+
+	    case bfd_reloc_dangerous:
+	      msg = _ ("internal error: dangerous error");
+	      goto common_error;
+
+	    default:
+	      msg = _ ("internal error: unknown error");
+	      /* fall through */
+
+	    common_error:
+	      if (!((*info->callbacks->warning)
+		    (info, msg, name, input_bfd, input_section,
+		     rel->r_offset)))
+		return false;
+	      break;
+	    }
+	}
+    }
+
+  return true;
+}
+
+
 
 /* Set and control ELF flags in ELF header.  */
 
@@ -582,8 +1631,11 @@ _bfd_m68hc11_elf_print_private_bfd_data 
 
 #define elf_info_to_howto	0
 #define elf_info_to_howto_rel	m68hc11_info_to_howto_rel
+#define bfd_elf32_bfd_relax_section  m68hc11_elf_relax_section
 #define elf_backend_gc_mark_hook     elf32_m68hc11_gc_mark_hook
 #define elf_backend_gc_sweep_hook    elf32_m68hc11_gc_sweep_hook
+#define elf_backend_check_relocs     elf32_m68hc11_check_relocs
+#define elf_backend_relocate_section elf32_m68hc11_relocate_section
 #define elf_backend_object_p	0
 #define elf_backend_final_write_processing	0
 #define elf_backend_can_gc_sections		1

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