Long branch stubs, multiple stub sections.

	* emultempl/ppc64elf.em: Include ldctor.h.
	(stub_file): New var.
	(group_size): New var.
	(ppc_create_output_section_statements): New function.
	(struct hook_stub_info): New.
	(hook_in_stub): New function.
	(ppc_add_stub_section): New function.
	(ppc_layout_sections_again): New function.
	(build_section_lists): New function.
	(gld${EMULATION_NAME}_finish): Rewrite.
	(real_func): New var.
	(ppc_for_each_input_file_wrapper): New function.
	(ppc_lang_for_each_input_file): New function.
	(lang_for_each_input_file): Define.
	(PARSE_AND_LIST_PROLOGUE): Define.
	(PARSE_AND_LIST_LONGOPTS): Define.
	(PARSE_AND_LIST_OPTIONS): Define.
	(PARSE_AND_LIST_ARGS_CASES): Define.
	(LDEMUL_CREATE_OUTPUT_SECTION_STATEMENTS): Define.

1 files changed, 291 insertions, 26 deletions

diff --git a/ld/emultempl/ppc64elf.em b/ld/emultempl/ppc64elf.em
index 65b824e..a96bb22 100644
--- a/ld/emultempl/ppc64elf.em
+++ b/ld/emultempl/ppc64elf.em
@@ -23,12 +23,199 @@
 #
 cat >>e${EMULATION_NAME}.c <<EOF
 
+#include "ldctor.h"
 #include "elf64-ppc.h"
 
+/* Fake input file for stubs.  */
+static lang_input_statement_type *stub_file;
+
+/* Whether we need to call ppc_layout_sections_again.  */
 static int need_laying_out = 0;
 
+/* Maximum size of a group of input sections that can be handled by
+   one stub section.  A value of +/-1 indicates the bfd back-end
+   should use a suitable default size.  */
+static bfd_signed_vma group_size = 1;
+
+static void ppc_create_output_section_statements PARAMS ((void));
+static asection *ppc_add_stub_section PARAMS ((const char *, asection *));
+static void ppc_layout_sections_again PARAMS ((void));
 static void gld${EMULATION_NAME}_after_allocation PARAMS ((void));
-static void gld${EMULATION_NAME}_finish PARAMS ((void));
+static void build_section_lists PARAMS ((lang_statement_union_type *));
+
+/* This is called before the input files are opened.  We create a new
+   fake input file to hold the stub sections.  */
+
+static void
+ppc_create_output_section_statements ()
+{
+  stub_file = lang_add_input_file ("linker stubs",
+				   lang_input_file_is_fake_enum,
+				   NULL);
+  stub_file->the_bfd = bfd_create ("linker stubs", output_bfd);
+  if (stub_file->the_bfd == NULL
+      || !bfd_set_arch_mach (stub_file->the_bfd,
+			     bfd_get_arch (output_bfd),
+			     bfd_get_mach (output_bfd)))
+    {
+      einfo ("%X%P: can not create BFD %E\n");
+      return;
+    }
+
+  ldlang_add_file (stub_file);
+}
+
+
+struct hook_stub_info
+{
+  lang_statement_list_type add;
+  asection *input_section;
+};
+
+/* Traverse the linker tree to find the spot where the stub goes.  */
+
+static boolean hook_in_stub
+  PARAMS ((struct hook_stub_info *, lang_statement_union_type **));
+
+static boolean
+hook_in_stub (info, lp)
+     struct hook_stub_info *info;
+     lang_statement_union_type **lp;
+{
+  lang_statement_union_type *l;
+  boolean ret;
+
+  for (; (l = *lp) != NULL; lp = &l->header.next)
+    {
+      switch (l->header.type)
+	{
+	case lang_constructors_statement_enum:
+	  ret = hook_in_stub (info, &constructor_list.head);
+	  if (ret)
+	    return ret;
+	  break;
+
+	case lang_output_section_statement_enum:
+	  ret = hook_in_stub (info,
+			      &l->output_section_statement.children.head);
+	  if (ret)
+	    return ret;
+	  break;
+
+	case lang_wild_statement_enum:
+	  ret = hook_in_stub (info, &l->wild_statement.children.head);
+	  if (ret)
+	    return ret;
+	  break;
+
+	case lang_group_statement_enum:
+	  ret = hook_in_stub (info, &l->group_statement.children.head);
+	  if (ret)
+	    return ret;
+	  break;
+
+	case lang_input_section_enum:
+	  if (l->input_section.section == info->input_section)
+	    {
+	      /* We've found our section.  Insert the stub immediately
+		 before its associated input section.  */
+	      *lp = info->add.head;
+	      *(info->add.tail) = l;
+	      return true;
+	    }
+	  break;
+
+	case lang_data_statement_enum:
+	case lang_reloc_statement_enum:
+	case lang_object_symbols_statement_enum:
+	case lang_output_statement_enum:
+	case lang_target_statement_enum:
+	case lang_input_statement_enum:
+	case lang_assignment_statement_enum:
+	case lang_padding_statement_enum:
+	case lang_address_statement_enum:
+	case lang_fill_statement_enum:
+	  break;
+
+	default:
+	  FAIL ();
+	  break;
+	}
+    }
+  return false;
+}
+
+
+/* Call-back for ppc64_elf_size_stubs.  */
+
+/* Create a new stub section, and arrange for it to be linked
+   immediately before INPUT_SECTION.  */
+
+static asection *
+ppc_add_stub_section (stub_sec_name, input_section)
+     const char *stub_sec_name;
+     asection *input_section;
+{
+  asection *stub_sec;
+  flagword flags;
+  asection *output_section;
+  const char *secname;
+  lang_output_section_statement_type *os;
+  struct hook_stub_info info;
+
+  stub_sec = bfd_make_section_anyway (stub_file->the_bfd, stub_sec_name);
+  if (stub_sec == NULL)
+    goto err_ret;
+
+  flags = (SEC_ALLOC | SEC_LOAD | SEC_READONLY | SEC_CODE
+	   | SEC_HAS_CONTENTS | SEC_RELOC | SEC_IN_MEMORY | SEC_KEEP);
+  if (!bfd_set_section_flags (stub_file->the_bfd, stub_sec, flags))
+    goto err_ret;
+
+  output_section = input_section->output_section;
+  secname = bfd_get_section_name (output_section->owner, output_section);
+  os = lang_output_section_find (secname);
+
+  info.input_section = input_section;
+  lang_list_init (&info.add);
+  lang_add_section (&info.add, stub_sec, os, stub_file);
+
+  if (info.add.head == NULL)
+    goto err_ret;
+
+  if (hook_in_stub (&info, &os->children.head))
+    return stub_sec;
+
+ err_ret:
+  einfo ("%X%P: can not make stub section: %E\n");
+  return NULL;
+}
+
+
+/* Another call-back for ppc64_elf_size_stubs.  */
+
+static void
+ppc_layout_sections_again ()
+{
+  /* If we have changed sizes of the stub sections, then we need
+     to recalculate all the section offsets.  This may mean we need to
+     add even more stubs.  */
+  need_laying_out = 0;
+
+  lang_reset_memory_regions ();
+
+  /* Resize the sections.  */
+  lang_size_sections (stat_ptr->head, abs_output_section,
+		      &stat_ptr->head, 0, (bfd_vma) 0, NULL);
+
+  /* Recalculate TOC base.  */
+  ldemul_after_allocation ();
+
+  /* Do the assignments again.  */
+  lang_do_assignments (stat_ptr->head, abs_output_section,
+		       (fill_type *) 0, (bfd_vma) 0);
+}
+
 
 /* Call the back-end function to set TOC base after we have placed all
    the sections.  */
@@ -39,14 +226,26 @@ gld${EMULATION_NAME}_after_allocation ()
     einfo ("%X%P: can not set TOC base: %E\n");
 }
 
-/* Final emulation specific call.  PowerPC64 has 24 byte .plt entries,
-   and needs different call stubs for any entries that cross a 64k
-   boundary relative to the TOC.  That means we need to wait until all
-   sections have been laid out to initialise the stubs.  */
+
+static void
+build_section_lists (statement)
+     lang_statement_union_type *statement;
+{
+  if (statement->header.type == lang_input_section_enum
+      && !statement->input_section.ifile->just_syms_flag)
+    {
+      ppc64_elf_next_input_section (output_bfd, &link_info,
+				    statement->input_section.section);
+    }
+}
+
+/* Final emulation specific call.  */
 
 static void
 gld${EMULATION_NAME}_finish ()
 {
+  int ret;
+
   /* e_entry on PowerPC64 points to the function descriptor for
      _start.  If _start is missing, default to the first function
      descriptor in the .opd section.  */
@@ -60,47 +259,113 @@ gld${EMULATION_NAME}_finish ()
   /* bfd_elf64_discard_info just plays with debugging sections,
      ie. doesn't affect any code, so we can delay resizing the
      sections.  It's likely we'll resize everything in the process of
-     adjusting stub sizes.  */
+     adding stubs.  */
   if (bfd_elf${ELFSIZE}_discard_info (output_bfd, &link_info))
     need_laying_out = 1;
 
-  while (1)
+  ret = ppc64_elf_setup_section_lists (output_bfd, &link_info);
+  if (ret != 0)
     {
+      if (ret < 0)
+	{
+	  einfo ("%X%P: can not size stub section: %E\n");
+	  return;
+	}
+
+      lang_for_each_statement (build_section_lists);
+
       /* Call into the BFD backend to do the real work.  */
-      if (! ppc64_elf_size_stubs (output_bfd, &link_info, &need_laying_out))
+      if (!ppc64_elf_size_stubs (output_bfd,
+				 stub_file->the_bfd,
+				 &link_info,
+				 group_size,
+				 &ppc_add_stub_section,
+				 &ppc_layout_sections_again))
 	{
 	  einfo ("%X%P: can not size stub section: %E\n");
 	  return;
 	}
+    }
 
-      if (!need_laying_out)
-	break;
+  if (need_laying_out)
+    ppc_layout_sections_again ();
 
-      /* If we have changed the size of the stub section, then we need
-	 to recalculate all the section offsets.  After this, we may
-	 need to adjust the stub size again.  */
-      need_laying_out = 0;
+  if (stub_file->the_bfd->sections != NULL)
+    {
+      if (!ppc64_elf_build_stubs (&link_info))
+	einfo ("%X%P: can not build stubs: %E\n");
+    }
+}
 
-      lang_reset_memory_regions ();
 
-      /* Resize the sections.  */
-      lang_size_sections (stat_ptr->head, abs_output_section,
-			  &stat_ptr->head, 0, (bfd_vma) 0, NULL);
+/* Avoid processing the fake stub_file in vercheck, stat_needed and
+   check_needed routines.  */
 
-      /* Recalculate TOC base.  */
-      ldemul_after_allocation ();
+static void ppc_for_each_input_file_wrapper
+  PARAMS ((lang_input_statement_type *));
+static void ppc_lang_for_each_input_file
+  PARAMS ((void (*) (lang_input_statement_type *)));
 
-      /* Do the assignments again.  */
-      lang_do_assignments (stat_ptr->head, abs_output_section,
-			   (fill_type *) 0, (bfd_vma) 0);
-    }
+static void (*real_func) PARAMS ((lang_input_statement_type *));
 
-  if (! ppc64_elf_build_stubs (output_bfd, &link_info))
-    einfo ("%X%P: can not build stubs: %E\n");
+static void ppc_for_each_input_file_wrapper (l)
+     lang_input_statement_type *l;
+{
+  if (l != stub_file)
+    (*real_func) (l);
 }
+
+static void
+ppc_lang_for_each_input_file (func)
+     void (*func) PARAMS ((lang_input_statement_type *));
+{
+  real_func = func;
+  lang_for_each_input_file (&ppc_for_each_input_file_wrapper);
+}
+
+#define lang_for_each_input_file ppc_lang_for_each_input_file
+
 EOF
 
+# Define some shell vars to insert bits of code into the standard elf
+# parse_args and list_options functions.
+#
+PARSE_AND_LIST_PROLOGUE='
+#define OPTION_STUBGROUP_SIZE		301
+'
+
+# The options are repeated below so that no abbreviations are allowed.
+# Otherwise -s matches stub-group-size
+PARSE_AND_LIST_LONGOPTS='
+  { "stub-group-size", required_argument, NULL, OPTION_STUBGROUP_SIZE },
+  { "stub-group-size", required_argument, NULL, OPTION_STUBGROUP_SIZE },
+'
+
+PARSE_AND_LIST_OPTIONS='
+  fprintf (file, _("\
+  --stub-group-size=N   Maximum size of a group of input sections that can be\n\
+                          handled by one stub section.  A negative value\n\
+                          locates all stubs before their branches (with a\n\
+                          group size of -N), while a positive value allows\n\
+                          two groups of input sections, one before, and one\n\
+                          after each stub section.  Values of +/-1 indicate\n\
+                          the linker should choose suitable defaults.\n"
+		   ));
+'
+
+PARSE_AND_LIST_ARGS_CASES='
+    case OPTION_STUBGROUP_SIZE:
+      {
+	const char *end;
+        group_size = bfd_scan_vma (optarg, &end, 0);
+        if (*end)
+	  einfo (_("%P%F: invalid number `%s'\''\n"), optarg);
+      }
+      break;
+'
+
 # Put these extra ppc64elf routines in ld_${EMULATION_NAME}_emulation
 #
 LDEMUL_AFTER_ALLOCATION=gld${EMULATION_NAME}_after_allocation
 LDEMUL_FINISH=gld${EMULATION_NAME}_finish
+LDEMUL_CREATE_OUTPUT_SECTION_STATEMENTS=ppc_create_output_section_statements