* elfxx-mips.c (_bfd_mips_relax_section): New function.

* elfxx-mips.h (_bfd_mips_relax_section): Declare.
* elfn32-mips.c, elf64-mips.c: Use it.

1 files changed, 179 insertions, 0 deletions

diff --git a/bfd/elfxx-mips.c b/bfd/elfxx-mips.c
index 2b2f615..c8c9870 100644
--- a/bfd/elfxx-mips.c
+++ b/bfd/elfxx-mips.c
@@ -5451,6 +5451,185 @@ _bfd_mips_elf_check_relocs (abfd, info, sec, relocs)
   return TRUE;
 }
 
+bfd_boolean
+_bfd_mips_relax_section (abfd, sec, link_info, again)
+     bfd *abfd;
+     asection *sec;
+     struct bfd_link_info *link_info;
+     bfd_boolean *again;
+{
+  Elf_Internal_Rela *internal_relocs;
+  Elf_Internal_Rela *irel, *irelend;
+  Elf_Internal_Shdr *symtab_hdr;
+  bfd_byte *contents = NULL;
+  bfd_byte *free_contents = NULL;
+  size_t extsymoff;
+  bfd_boolean changed_contents = FALSE;
+  bfd_vma sec_start = sec->output_section->vma + sec->output_offset;
+  Elf_Internal_Sym *isymbuf = NULL;
+
+  /* We are not currently changing any sizes, so only one pass.  */
+  *again = FALSE;
+
+  if (link_info->relocateable)
+    return TRUE;
+
+  internal_relocs = (MNAME(abfd,_bfd_elf,link_read_relocs)
+                     (abfd, sec, (PTR) NULL, (Elf_Internal_Rela *) NULL,
+                      link_info->keep_memory));
+  if (internal_relocs == NULL)
+    return TRUE;
+
+  irelend = internal_relocs + sec->reloc_count
+    * get_elf_backend_data (abfd)->s->int_rels_per_ext_rel;
+  symtab_hdr = &elf_tdata (abfd)->symtab_hdr;
+  extsymoff = (elf_bad_symtab (abfd)) ? 0 : symtab_hdr->sh_info;
+
+  for (irel = internal_relocs; irel < irelend; irel++)
+    {
+      bfd_vma symval;
+      bfd_signed_vma sym_offset;
+      unsigned int r_type;
+      unsigned long r_symndx;
+      asection *sym_sec;
+      unsigned long instruction;
+
+      /* Turn jalr into bgezal, and jr into beq, if they're marked
+	 with a JALR relocation, that indicate where they jump to.
+	 This saves some pipeline bubbles.  */
+      r_type = ELF_R_TYPE (abfd, irel->r_info);
+      if (r_type != R_MIPS_JALR)
+	continue;
+
+      r_symndx = ELF_R_SYM (abfd, irel->r_info);
+      /* Compute the address of the jump target.  */
+      if (r_symndx >= extsymoff)
+	{
+	  struct mips_elf_link_hash_entry *h
+	    = ((struct mips_elf_link_hash_entry *)
+	       elf_sym_hashes (abfd) [r_symndx - extsymoff]);
+
+	  while (h->root.root.type == bfd_link_hash_indirect
+		 || h->root.root.type == bfd_link_hash_warning)
+	    h = (struct mips_elf_link_hash_entry *) h->root.root.u.i.link;
+	  
+	  /* If a symbol is undefined, or if it may be overridden,
+	     skip it.  */
+	  if (! ((h->root.root.type == bfd_link_hash_defined
+		  || h->root.root.type == bfd_link_hash_defweak)
+		 && h->root.root.u.def.section)
+	      || (link_info->shared && ! link_info->symbolic
+		  && ! (h->root.elf_link_hash_flags & ELF_LINK_FORCED_LOCAL)))
+	    continue;
+
+	  sym_sec = h->root.root.u.def.section;
+	  if (sym_sec->output_section)
+	    symval = (h->root.root.u.def.value
+		      + sym_sec->output_section->vma
+		      + sym_sec->output_offset);
+	  else
+	    symval = h->root.root.u.def.value;
+	}
+      else
+	{
+	  Elf_Internal_Sym *isym;
+
+	  /* Read this BFD's symbols if we haven't done so already.  */
+	  if (isymbuf == NULL && symtab_hdr->sh_info != 0)
+	    {
+	      isymbuf = (Elf_Internal_Sym *) symtab_hdr->contents;
+	      if (isymbuf == NULL)
+		isymbuf = bfd_elf_get_elf_syms (abfd, symtab_hdr,
+						symtab_hdr->sh_info, 0,
+						NULL, NULL, NULL);
+	      if (isymbuf == NULL)
+		goto relax_return;
+	    }
+
+	  isym = isymbuf + r_symndx;
+	  if (isym->st_shndx == SHN_UNDEF)
+	    continue;
+	  else if (isym->st_shndx == SHN_ABS)
+	    sym_sec = bfd_abs_section_ptr;
+	  else if (isym->st_shndx == SHN_COMMON)
+	    sym_sec = bfd_com_section_ptr;
+	  else
+	    sym_sec
+	      = bfd_section_from_elf_index (abfd, isym->st_shndx);
+	  symval = isym->st_value
+	    + sym_sec->output_section->vma
+	    + sym_sec->output_offset;
+	}
+
+      /* Compute branch offset, from delay slot of the jump to the
+	 branch target.  */
+      sym_offset = (symval + irel->r_addend)
+	- (sec_start + irel->r_offset + 4);
+
+      /* Branch offset must be properly aligned.  */
+      if ((sym_offset & 3) != 0)
+	continue;
+
+      sym_offset >>= 2;
+
+      /* Check that it's in range.  */
+      if (sym_offset < -0x8000 || sym_offset >= 0x8000)
+	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
+	    {
+	      contents = (bfd_byte *) bfd_malloc (sec->_raw_size);
+	      if (contents == NULL)
+		goto relax_return;
+
+	      free_contents = contents;
+	      if (! bfd_get_section_contents (abfd, sec, contents,
+					      (file_ptr) 0, sec->_raw_size))
+		goto relax_return;
+	    }
+	}
+
+      instruction = bfd_get_32 (abfd, contents + irel->r_offset);
+
+      /* If it was jalr <reg>, turn it into bgezal $zero, <target>.  */
+      if ((instruction & 0xfc1fffff) == 0x0000f809)
+	instruction = 0x04110000;
+      /* If it was jr <reg>, turn it into b <target>.  */
+      else if ((instruction & 0xfc1fffff) == 0x00000008)
+	instruction = 0x10000000;
+      else
+	continue;
+
+      instruction |= (sym_offset & 0xffff);
+      bfd_put_32 (abfd, instruction, contents + irel->r_offset);
+      changed_contents = TRUE;
+    }
+
+  if (contents != NULL
+      && elf_section_data (sec)->this_hdr.contents != contents)
+    {
+      if (!changed_contents && !link_info->keep_memory)
+        free (contents);
+      else
+        {
+          /* Cache the section contents for elf_link_input_bfd.  */
+          elf_section_data (sec)->this_hdr.contents = contents;
+        }
+    }
+  return TRUE;
+
+ relax_return:  
+  if (free_contents != NULL)
+    free (free_contents);
+  return FALSE;
+}
+
 /* Adjust a symbol defined by a dynamic object and referenced by a
    regular object.  The current definition is in some section of the
    dynamic object, but we're not including those sections.  We have to