xcoff: implement linker relaxation

bfd/ChangeLog:

	* coff-rs6000.c (xcoff_reloc_type_noop): Add info argument.
	(xcoff_reloc_type_fail): Likewise.
	(xcoff_reloc_type_pos): Likewise.
	(xcoff_reloc_type_neg): Likewise.
	(xcoff_reloc_type_rel): Likewise.
	(xcoff_reloc_type_toc): Likewise.
	(xcoff_reloc_type_ba): Likewise.
	(xcoff_reloc_type_crel): Likewise.
	(xcoff_reloc_type_tls): Likewise.
	(xcoff_reloc_type_br): Add stub handler.
	(xcoff_ppc_relocate_section): Add info to
	xcoff_calculate_relocation.
	(xcoff_stub_indirect_call_code): New constant.
	(xcoff_stub_shared_call_code): Likewise.
	(bfd_xcoff_backend_data): Add stub code fields.
	(bfd_pmac_xcoff_backend_data): Likewise.
	* coff64-rs6000.c (xcoff64_reloc_type_br): Add stub handler.
	(xcoff64_ppc_relocate_section): Add info to
	xcoff64_calculate_relocation.
	(xcoff64_stub_indirect_call_code): New constant.
	(xcoff64_stub_shared_call_code): Likewise.
	(bfd_xcoff_backend_data): Add stub code fields.
	(bfd_xcoff_aix5_backend_data): Likewise.
	* libxcoff.h (struct xcoff_backend_data_rec): Add stub fields.
	(bfd_xcoff_stub_indirect_call_code): New define.
	(bfd_xcoff_stub_indirect_call_size): New define.
	(bfd_xcoff_stub_shared_call_code): New define.
	(bfd_xcoff_stub_shared_call_size): New define.
	(xcoff_reloc_function): Add info argument.
	(enum xcoff_stub_type): New enum.
	(struct xcoff_stub_hash_entry): New structure.
	* xcofflink.c (struct xcoff_link_hash_table): Add stub hash
	table and params fields.
	(xcoff_stub_hash_entry): New define.
	(xcoff_stub_hash_lookup): New define.
	(stub_hash_newfunc): New function.
	(_bfd_xcoff_bfd_link_hash_table_free): Free the new stub hash
	table.
	(_bfd_xcoff_bfd_link_hash_table_create): Create the new stub
	hash table.
	(xcoff_link_add_symbols): Save rawsize for XTY_SD.
	(bfd_xcoff_link_init): New function.
	(xcoff_stub_csect_name): New function.
	(xcoff_stub_get_csect_in_range): New function.
	(xcoff_stub_name): New function.
	(bfd_xcoff_get_stub_entry): New function.
	(bfd_xcoff_type_of_stub): New function.
	(xcoff_add_stub): New function.
	(xcoff_build_one_stub): New function.
	(bfd_xcoff_size_stubs): New function.
	(bfd_xcoff_build_stubs): New function.
	(xcoff_stub_create_relocations): New function.
	(xcoff_link_input_bfd): Adapt relocations to stub.
	(xcoff_write_global_symbol): Adapt to new TOC entries generated
	for stubs.
	(_bfd_xcoff_bfd_final_link): Handle stub file.
	* xcofflink.h (struct bfd_xcoff_link_params): New structure.

ld/ChangeLog:

	* emultempl/aix.em (params): New variable.
	(stub_file): New variable.
	(xcoff_add_stub_section): New function.
	(xcoff_layout_sections_again): New function
	(hook_in_stub): New function.
	(_after_allocation): Add stub creation.
	(_create_output_section_statements): Allocate stub file and
	pass params to backend.

bfd/coff64-rs6000.c

@@ -778,10 +778,13 @@ xcoff64_reloc_type_br (bfd *input_bfd,
 		       bfd_vma val,
 		       bfd_vma addend,
 		       bfd_vma *relocation,
-		       bfd_byte *contents)
+		       bfd_byte *contents,
+		       struct bfd_link_info *info)
 {
   struct xcoff_link_hash_entry *h;
   bfd_vma section_offset;
+  struct xcoff_stub_hash_entry *stub_entry = NULL;
+  enum xcoff_stub_type stub_type;
 
   if (0 > rel->r_symndx)
     return false;
@@ -833,6 +836,27 @@ xcoff64_reloc_type_br (bfd *input_bfd,
       howto->complain_on_overflow = complain_overflow_dont;
     }
 
+  /* Check if a stub is needed.  */
+  stub_type = bfd_xcoff_type_of_stub (input_section, rel, val, h);
+  if (stub_type != xcoff_stub_none)
+    {
+      asection *stub_csect;
+
+      stub_entry = bfd_xcoff_get_stub_entry (input_section, h, info);
+      if (stub_entry == NULL)
+	{
+	  _bfd_error_handler (_("Unable to find the stub entry targeting %s"),
+			      h->root.root.string);
+	  bfd_set_error (bfd_error_bad_value);
+	  return false;
+	}
+
+      stub_csect = stub_entry->hcsect->root.u.def.section;
+      val = (stub_entry->stub_offset
+	     + stub_csect->output_section->vma
+	     + stub_csect->output_offset);
+    }
+
   /* The original PC-relative relocation is biased by -r_vaddr, so adding
      the value below will give the absolute target address.  */
   *relocation = val + addend + rel->r_vaddr;
@@ -1645,7 +1669,7 @@ xcoff64_ppc_relocate_section (bfd *output_bfd,
       if (rel->r_type >= XCOFF_MAX_CALCULATE_RELOCATION
 	  || !((*xcoff64_calculate_relocation[rel->r_type])
 	      (input_bfd, input_section, output_bfd, rel, sym, &howto, val,
-	       addend, &relocation, contents)))
+	       addend, &relocation, contents, info)))
 	return false;
 
       /* address */
@@ -2386,12 +2410,32 @@ HOWTO (0,			/* type */
        MINUS_ONE,		/* dst_mask */
        false);			/* pcrel_offset */
 
+/* Indirect call stub */
+static const unsigned long xcoff64_stub_indirect_call_code[4] =
+  {
+    0xe9820000,	/* ld r12,0(r2) */
+    0xe80c0000,	/* ld r0,0(r12) */
+    0x7c0903a6,	/* mtctr r0 */
+    0x4e800420,	/* bctr */
+  };
+
+/* Shared call stub */
+static const unsigned long xcoff64_stub_shared_call_code[6] =
+  {
+    0xe9820000,	/* ld r12,0(r2) */
+    0xf8410028,	/* std r2,40(r1) */
+    0xe80c0000,	/* ld r0,0(r12) */
+    0xe84c0008,	/* ld r2,8(r12) */
+    0x7c0903a6,	/* mtctr r0 */
+    0x4e800420,	/* bctr */
+  };
+
 static const unsigned long xcoff64_glink_code[10] =
 {
   0xe9820000,	/* ld r12,0(r2) */
   0xf8410028,	/* std r2,40(r1) */
   0xe80c0000,	/* ld r0,0(r12) */
-  0xe84c0008,	/* ld r0,8(r12) */
+  0xe84c0008,	/* ld r2,8(r12) */
   0x7c0903a6,	/* mtctr r0 */
   0x4e800420,	/* bctr */
   0x00000000,	/* start of traceback table */
@@ -2495,6 +2539,14 @@ static const struct xcoff_backend_data_rec bfd_xcoff_backend_data =
     /* rtinit.  */
     88,				/* _xcoff_rtinit_size */
     xcoff64_generate_rtinit,
+
+    /* Stub indirect call.  */
+    &xcoff64_stub_indirect_call_code[0],
+    16,				/* _xcoff_stub_indirect_call_size */
+
+    /* Stub shared call.  */
+    &xcoff64_stub_shared_call_code[0],
+    24,				/* _xcoff_stub_shared_call_size */
   };
 
 /* The transfer vector that leads the outside world to all of the above.  */
@@ -2759,6 +2811,14 @@ static const struct xcoff_backend_data_rec bfd_xcoff_aix5_backend_data =
     /* rtinit.  */
     88,				/* _xcoff_rtinit_size */
     xcoff64_generate_rtinit,
+
+    /* Stub indirect call.  */
+    &xcoff64_stub_indirect_call_code[0],
+    16,				/* _xcoff_stub_indirect_call_size */
+
+    /* Stub shared call.  */
+    &xcoff64_stub_shared_call_code[0],
+    24,				/* _xcoff_stub_shared_call_size */
   };
 
 /* The transfer vector that leads the outside world to all of the above.  */