Nios II CALL26 linker relaxation

2014-01-30  Sandra Loosemore  <sandra@codesourcery.com>

	bfd/
	* bfd-in2.h: Update from reloc.c.
	* elf32-nios2.c: Include elf32-nios2.h.
	(elf_nios2_howto_table_rel): Add entry for R_NIOS2_CALL26_NOAT.
	(nios2_reloc_map): Likewise.
	(enum elf32_nios2_stub_type): Declare.
	(struct elf32_nios2_stub_hash_entry): Declare.
	(nios2_stub_hash_entry, nios2_stub_hash_lookup): New macros.
	(struct elf32_nios2_link_hash_entry): Add hsh_cache field.
	(struct elf32_nios2_link_hash_table): Add new fields bstab,
	stub_bfd, add_stub_section, layout_sections_again, stub_group,
	bfd_count, top_index, input_list, all_local_syms.
	(nios2_call26_stub_entry): New.
	(nios2_elf32_install_imm16): Move up in file.
	(nios2_elf32_install_data): Move up in file.
	(hiadj): Move up in file.
	(stub_hash_newfunc): New.
	(link_hash_newfunc): Initialize hsh_cache field.
	(STUB_SUFFIX): New.
	(nios2_stub_name): New.
	(nios2_get_stub_entry): New.
	(nios2_add_stub): New.
	(nios2_elf32_setup_section_lists): New.
	(nios2_elf32_next_input_section): New.
	(CALL26_SEGMENT): New.
	(MAX_STUB_SECTION_SIZE): New.
	(group_sections): New.
	(nios2_type_of_stub): New.
	(nios2_build_one_stub): New.
	(nios2_size_one_stub): New.
	(get_local_syms): New.
	(nios2_elf32_size_stubs): New.
	(nios2_elf32_build_stubs): New.
	(nios2_elf32_do_call26_relocate): Correct CALL26 overflow test.
	(nios2_elf32_relocate_section): Handle R_NIOS2_CALL26_NOAT.  Add
	trampolines for R_NIOS2_CALL26 stubs.
	(nios2_elf32_check_relocs): Handle R_NIOS2_CALL26_NOAT.
	(nios2_elf32_gc_sweep_hook): Likewise.
	(nios2_elf32_link_hash_table_create): Initialize the stub hash table.
	(nios2_elf32_link_hash_table_free): New.
	(bfd_elf32_bfd_link_hash_table_free): Define.
	* elf32-nios2.h: New file.
	* libbfd.h: Update from reloc.c.
	* reloc.c (BFD_RELOC_NIOS2_CALL26_NOAT): New.

	gas/
	* config/tc-nios2.c (md_apply_fix): Handle BFD_RELOC_NIOS2_CALL26_NOAT.
	(nios2_assemble_args_m): Likewise.
	(md_assemble): Likewise.

	gas/testsuite/
	* gas/nios2/call26_noat.d: New.
	* gas/nios2/call26_noat.s: New.
	* gas/nios2/call_noat.d: New.
	* gas/nios2/call_noat.s: New.

	include/elf/
	* nios2.h (elf_nios2_reloc_type): Add R_NIOS2_CALL26_NOAT.

	ld/
	* Makefile.am (enios2elf.c, enios2linux.c): Update dependencies.
	* Makefile.in: Regenerated.
	* emulparams/nios2elf.sh (EXTRA_EM_FILE): Set.
	* emulparams/nios2linux.sh (EXTRA_EM_FILE): Set.
	* emultempl/nios2elf.em: New file.
	* gen-doc.texi (NIOSII): Set.
	* ld.texinfo (NIOSII): Set.

	ld/testsuite/
	* ld-nios2/relax_call26.s: New.
	* ld-nios2/relax_call26_boundary.ld: New.
	* ld-nios2/relax_call26_boundary.s: New.
	* ld-nios2/relax_call26_boundary_c8.d: New.
	* ld-nios2/relax_call26_boundary_cc.d: New.
	* ld-nios2/relax_call26_boundary_d0.d: New.
	* ld-nios2/relax_call26_boundary_d4.d: New.
	* ld-nios2/relax_call26_boundary_d8.d: New.
	* ld-nios2/relax_call26_boundary_dc.d: New.
	* ld-nios2/relax_call26_boundary_f0.d: New.
	* ld-nios2/relax_call26_boundary_f4.d: New.
	* ld-nios2/relax_call26_boundary_f8.d: New.
	* ld-nios2/relax_call26_boundary_fc.d: New.
	* ld-nios2/relax_call26_cache.d: New.
	* ld-nios2/relax_call26_cache.ld: New.
	* ld-nios2/relax_call26_cache.s: New.
	* ld-nios2/relax_call26_multi.d: New.
	* ld-nios2/relax_call26_multi.ld: New.
	* ld-nios2/relax_call26_norelax.d: New.
	* ld-nios2/relax_call26_shared.d: New.
	* ld-nios2/relax_call26_shared.ld: New.

1 files changed, 317 insertions, 0 deletions

diff --git a/ld/emultempl/nios2elf.em b/ld/emultempl/nios2elf.em
new file mode 100644
index 0000000000..c86eba1f52
--- /dev/null
+++ b/ld/emultempl/nios2elf.em
@@ -0,0 +1,317 @@
+# This shell script emits a C file. -*- C -*-
+#   Copyright (C) 2013, 2014 Free Software Foundation, Inc.
+#
+# This file is part of GNU Binutils.
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
+# MA 02110-1301, USA.
+#
+
+# This file is sourced from elf32.em, and defines extra Nios II ELF
+# specific routines. Taken from metagelf.em.
+#
+fragment <<EOF
+
+#include "ldctor.h"
+#include "elf32-nios2.h"
+
+
+/* Fake input file for stubs.  */
+static lang_input_statement_type *stub_file;
+
+/* Whether we need to call nios2_layout_sections_again.  */
+static int need_laying_out = 0;
+
+
+/* This is called before the input files are opened.  We create a new
+   fake input file to hold the stub sections.  */
+
+static void
+nios2elf_create_output_section_statements (void)
+{
+  extern const bfd_target bfd_elf32_littlenios2_vec, bfd_elf32_bignios2_vec;
+
+  if (link_info.output_bfd->xvec != &bfd_elf32_littlenios2_vec
+      && link_info.output_bfd->xvec != &bfd_elf32_bignios2_vec)
+    return;
+
+  /* If --no-relax was not explicitly specified by the user, enable
+     relaxation.  If it's not enabled (either explicitly or by default),
+     we're done, as we won't need to create any stubs.  */
+  if (!link_info.relocatable && RELAXATION_DISABLED_BY_DEFAULT)
+    ENABLE_RELAXATION;
+  if (!RELAXATION_ENABLED)
+    return;
+
+  stub_file = lang_add_input_file ("linker stubs",
+				   lang_input_file_is_fake_enum,
+				   NULL);
+  stub_file->the_bfd = bfd_create ("linker stubs", link_info.output_bfd);
+  if (stub_file->the_bfd == NULL
+      || ! bfd_set_arch_mach (stub_file->the_bfd,
+			      bfd_get_arch (link_info.output_bfd),
+			      bfd_get_mach (link_info.output_bfd)))
+    {
+      einfo ("%X%P: can not create BFD %E\n");
+      return;
+    }
+
+  stub_file->the_bfd->flags |= BFD_LINKER_CREATED;
+  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 bfd_boolean
+hook_in_stub (struct hook_stub_info *info, lang_statement_union_type **lp,
+	      bfd_boolean afterp)
+{
+  lang_statement_union_type *l;
+  bfd_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, afterp);
+	  if (ret)
+	    return ret;
+	  break;
+
+	case lang_output_section_statement_enum:
+	  ret = hook_in_stub (info,
+			      &l->output_section_statement.children.head,
+			      afterp);
+	  if (ret)
+	    return ret;
+	  break;
+
+	case lang_wild_statement_enum:
+	  ret = hook_in_stub (info, &l->wild_statement.children.head, afterp);
+	  if (ret)
+	    return ret;
+	  break;
+
+	case lang_group_statement_enum:
+	  ret = hook_in_stub (info, &l->group_statement.children.head, afterp);
+	  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 or after its associated input section.  */
+	      if (afterp)
+		{
+		  *(info->add.tail) = l->header.next;
+		  l->header.next = info->add.head;
+		}
+	      else
+		{
+		  *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 elf32_nios2_size_stubs.  */
+
+/* Create a new stub section, and arrange for it to be linked
+   immediately before or after INPUT_SECTION, according to AFTERP.  */
+
+static asection *
+nios2elf_add_stub_section (const char *stub_sec_name, asection *input_section,
+			   bfd_boolean afterp)
+{
+  asection *stub_sec;
+  flagword flags;
+  asection *output_section;
+  const char *secname;
+  lang_output_section_statement_type *os;
+  struct hook_stub_info info;
+
+  flags = (SEC_ALLOC | SEC_LOAD | SEC_READONLY | SEC_CODE
+	   | SEC_HAS_CONTENTS | SEC_RELOC | SEC_IN_MEMORY | SEC_KEEP);
+  stub_sec = bfd_make_section_anyway_with_flags (stub_file->the_bfd,
+						 stub_sec_name, flags);
+  if (stub_sec == NULL)
+    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, NULL, os);
+
+  if (info.add.head == NULL)
+    goto err_ret;
+
+  if (hook_in_stub (&info, &os->children.head, afterp))
+    return stub_sec;
+
+ err_ret:
+  einfo ("%X%P: can not make stub section: %E\n");
+  return NULL;
+}
+
+
+/* Another call-back for elf32_nios2_size_stubs.  */
+
+static void
+nios2elf_layout_sections_again (void)
+{
+  /* 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.  */
+  gld${EMULATION_NAME}_map_segments (TRUE);
+  need_laying_out = -1;
+}
+
+
+static void
+build_section_lists (lang_statement_union_type *statement)
+{
+  if (statement->header.type == lang_input_section_enum)
+    {
+      asection *i = statement->input_section.section;
+
+      if (i->sec_info_type != SEC_INFO_TYPE_JUST_SYMS
+	  && (i->flags & SEC_EXCLUDE) == 0
+	  && i->output_section != NULL
+	  && i->output_section->owner == link_info.output_bfd)
+	{
+	  nios2_elf32_next_input_section (&link_info, i);
+	}
+    }
+}
+
+
+/* For Nios II we use this opportunity to build linker stubs.  */
+
+static void
+gld${EMULATION_NAME}_after_allocation (void)
+{
+  /* bfd_elf_discard_info just plays with data and debugging sections,
+     ie. doesn't affect code size, so we can delay resizing the
+     sections.  It's likely we'll resize everything in the process of
+     adding stubs.  */
+  if (bfd_elf_discard_info (link_info.output_bfd, &link_info))
+    need_laying_out = 1;
+
+  /* If generating a relocatable output file, then we don't
+     have to examine the relocs.  */
+  if (stub_file != NULL && !link_info.relocatable && RELAXATION_ENABLED)
+    {
+      int ret = nios2_elf32_setup_section_lists (link_info.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 (! nios2_elf32_size_stubs (link_info.output_bfd,
+					stub_file->the_bfd,
+					&link_info,
+					&nios2elf_add_stub_section,
+					&nios2elf_layout_sections_again))
+	    {
+	      einfo ("%X%P: can not size stub section: %E\n");
+	      return;
+	    }
+	}
+    }
+
+  if (need_laying_out != -1)
+    gld${EMULATION_NAME}_map_segments (need_laying_out);
+
+  if (!link_info.relocatable && RELAXATION_ENABLED)
+    {
+      /* Now build the linker stubs.  */
+      if (stub_file != NULL && stub_file->the_bfd->sections != NULL)
+	{
+	  if (! nios2_elf32_build_stubs (&link_info))
+	    einfo ("%X%P: can not build stubs: %E\n");
+	}
+    }
+}
+
+
+/* Avoid processing the fake stub_file in vercheck, stat_needed and
+   check_needed routines.  */
+
+static void (*real_func) (lang_input_statement_type *);
+
+static void nios2_for_each_input_file_wrapper (lang_input_statement_type *l)
+{
+  if (l != stub_file)
+    (*real_func) (l);
+}
+
+static void
+nios2_lang_for_each_input_file (void (*func) (lang_input_statement_type *))
+{
+  real_func = func;
+  lang_for_each_input_file (&nios2_for_each_input_file_wrapper);
+}
+
+#define lang_for_each_input_file nios2_lang_for_each_input_file
+
+EOF
+
+
+# Put these extra nios2elf routines in ld_${EMULATION_NAME}_emulation
+#
+LDEMUL_AFTER_ALLOCATION=gld${EMULATION_NAME}_after_allocation
+LDEMUL_CREATE_OUTPUT_SECTION_STATEMENTS=nios2elf_create_output_section_statements