From: Paul Brook <paul@codesourcery.com>
Date: Mon, 9 May 2011 13:23:27 +0000 (+0000)
Subject: 2011-05-09  Paul Brook  <paul@codesourcery.com>
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=fbd9ad907dc6a283dc1bec51ecd91355ac866949;p=binutils-gdb.git

2011-05-09  Paul Brook  <paul@codesourcery.com>

	bfd/
	* bfd-in.h (elf32_tic6x_fix_exidx_coverage): Add prototype.
	* bfd-in2.h: Regenerate.
	* elf32-tic6x.c: Include limits.h.
	(tic6x_unwind_edit_type, tic6x_unwind_table_edit,
	_tic6x_elf_section_data): New.
	(elf32_tic6x_section_data): Define.
	(elf32_tic6x_new_section_hook): Allocate target specific data.
	(elf32_tic6x_add_unwind_table_edit): New function.
	(get_tic6x_elf_section_data, elf32_tic6x_adjust_exidx_size,
	elf32_tic6x_insert_cantunwind_after, elf32_tic6x_add_low31,
	elf32_tic6x_copy_exidx_entry): New functions.
	(elf_backend_write_section): Define.

	ld/
	* emultempl/tic6xdsbt.em (merge_exidx_entries): New.
	(compare_output_sec_vma): New function.
	(gld${EMULATION_NAME}_after_allocation): New function.
	(OPTION_NO_MERGE_EXIDX_ENTRIES): Define.
	(PARSE_AND_LIST_OPTIONS): Add --no-merge-exidx-entries.
	(PARSE_AND_LIST_ARGS_CASES): Add OPTION_NO_MERGE_EXIDX_ENTRIES.
	(LDEMUL_AFTER_ALLOCATION): Set.
	* ld.texinfo: Document c6x --no-merge-exidx-entries.

	ld/testsuite/
	* ld-tic6x/discard-unwind.ld: New.
	* ld-tic6x/unwind.ld: New.
	* ld-tic6x/unwind-1.d: New test.
	* ld-tic6x/unwind-1.s: New test.
	* ld-tic6x/unwind-2.d: New test.
	* ld-tic6x/unwind-2.s: New test.
	* ld-tic6x/unwind-3.d: New test.
	* ld-tic6x/unwind-3.s: New test.
	* ld-tic6x/unwind-4.d: New test.
	* ld-tic6x/unwind-4.s: New test.
	* ld-tic6x/unwind-5.d: New test.
	* ld-tic6x/unwind-5.s: New test.
	* ld-tic6x/unwind-6.d: New test.
---

diff --git a/bfd/ChangeLog b/bfd/ChangeLog
index e04ede9e96f..0687337a2e6 100644
--- a/bfd/ChangeLog
+++ b/bfd/ChangeLog
@@ -1,3 +1,18 @@
+2011-05-09  Paul Brook  <paul@codesourcery.com>
+
+	* bfd-in.h (elf32_tic6x_fix_exidx_coverage): Add prototype.
+	* bfd-in2.h: Regenerate.
+	* elf32-tic6x.c: Include limits.h.
+	(tic6x_unwind_edit_type, tic6x_unwind_table_edit,
+	_tic6x_elf_section_data): New.
+	(elf32_tic6x_section_data): Define.
+	(elf32_tic6x_new_section_hook): Allocate target specific data.
+	(elf32_tic6x_add_unwind_table_edit): New function.
+	(get_tic6x_elf_section_data, elf32_tic6x_adjust_exidx_size,
+	elf32_tic6x_insert_cantunwind_after, elf32_tic6x_add_low31,
+	elf32_tic6x_copy_exidx_entry): New functions.
+	(elf_backend_write_section): Define.
+
 2011-05-09  Paul Brook  <paul@codesourcery.com>
 
 	* elf32-tic6x.c (is_tic6x_elf_unwind_section_name,
diff --git a/bfd/bfd-in.h b/bfd/bfd-in.h
index d5368977912..21b7cc20e78 100644
--- a/bfd/bfd-in.h
+++ b/bfd/bfd-in.h
@@ -912,6 +912,10 @@ extern bfd_boolean elf32_arm_build_stubs
 extern bfd_boolean elf32_arm_fix_exidx_coverage
 (struct bfd_section **, unsigned int, struct bfd_link_info *, bfd_boolean);
 
+/* C6x unwind section editing support.  */
+extern bfd_boolean elf32_tic6x_fix_exidx_coverage
+(struct bfd_section **, unsigned int, struct bfd_link_info *, bfd_boolean);
+
 /* PowerPC @tls opcode transform/validate.  */
 extern unsigned int _bfd_elf_ppc_at_tls_transform
   (unsigned int, unsigned int);
diff --git a/bfd/bfd-in2.h b/bfd/bfd-in2.h
index 5076ccf31cc..4fd71e6ce2a 100644
--- a/bfd/bfd-in2.h
+++ b/bfd/bfd-in2.h
@@ -919,6 +919,10 @@ extern bfd_boolean elf32_arm_build_stubs
 extern bfd_boolean elf32_arm_fix_exidx_coverage
 (struct bfd_section **, unsigned int, struct bfd_link_info *, bfd_boolean);
 
+/* C6x unwind section editing support.  */
+extern bfd_boolean elf32_tic6x_fix_exidx_coverage
+(struct bfd_section **, unsigned int, struct bfd_link_info *, bfd_boolean);
+
 /* PowerPC @tls opcode transform/validate.  */
 extern unsigned int _bfd_elf_ppc_at_tls_transform
   (unsigned int, unsigned int);
diff --git a/bfd/elf32-tic6x.c b/bfd/elf32-tic6x.c
index a70ef01c05b..fb710dc1d9a 100644
--- a/bfd/elf32-tic6x.c
+++ b/bfd/elf32-tic6x.c
@@ -22,6 +22,7 @@
    MA 02110-1301, USA.  */
 
 #include "sysdep.h"
+#include <limits.h>
 #include "bfd.h"
 #include "libbfd.h"
 #include "libiberty.h"
@@ -75,6 +76,52 @@ struct elf32_tic6x_link_hash_entry
   struct elf_dyn_relocs *dyn_relocs;
 };
 
+typedef enum
+{
+  DELETE_EXIDX_ENTRY,
+  INSERT_EXIDX_CANTUNWIND_AT_END
+}
+tic6x_unwind_edit_type;
+
+/* A (sorted) list of edits to apply to an unwind table.  */
+typedef struct tic6x_unwind_table_edit
+{
+  tic6x_unwind_edit_type type;
+  /* Note: we sometimes want to insert an unwind entry corresponding to a
+     section different from the one we're currently writing out, so record the
+     (text) section this edit relates to here.  */
+  asection *linked_section;
+  unsigned int index;
+  struct tic6x_unwind_table_edit *next;
+}
+tic6x_unwind_table_edit;
+
+typedef struct _tic6x_elf_section_data
+{
+  /* Information about mapping symbols.  */
+  struct bfd_elf_section_data elf;
+  /* Information about unwind tables.  */
+  union
+  {
+    /* Unwind info attached to a text section.  */
+    struct
+    {
+      asection *tic6x_exidx_sec;
+    } text;
+
+    /* Unwind info attached to an .c6xabi.exidx section.  */
+    struct
+    {
+      tic6x_unwind_table_edit *unwind_edit_list;
+      tic6x_unwind_table_edit *unwind_edit_tail;
+    } exidx;
+  } u;
+}
+_tic6x_elf_section_data;
+
+#define elf32_tic6x_section_data(sec) \
+  ((_tic6x_elf_section_data *) elf_section_data (sec))
+
 struct elf32_tic6x_obj_tdata
 {
   struct elf_obj_tdata root;
@@ -2120,6 +2167,18 @@ elf32_tic6x_new_section_hook (bfd *abfd, asection *sec)
 {
   bfd_boolean ret;
 
+  /* Allocate target specific section data.  */
+  if (!sec->used_by_bfd)
+    {
+      _tic6x_elf_section_data *sdata;
+      bfd_size_type amt = sizeof (*sdata);
+
+      sdata = (_tic6x_elf_section_data *) bfd_zalloc (abfd, amt);
+      if (sdata == NULL)
+	return FALSE;
+      sec->used_by_bfd = sdata;
+    }
+
   ret = _bfd_elf_new_section_hook (abfd, sec);
   sec->use_rela_p = elf32_tic6x_tdata (abfd)->use_rela_p;
 
@@ -3977,6 +4036,409 @@ elf32_tic6x_copy_private_data (bfd * ibfd, bfd * obfd)
   return TRUE;
 }
 
+/* Add a new unwind edit to the list described by HEAD, TAIL.  If TINDEX is zero,
+   adds the edit to the start of the list.  (The list must be built in order of
+   ascending TINDEX: the function's callers are primarily responsible for
+   maintaining that condition).  */
+
+static void
+elf32_tic6x_add_unwind_table_edit (tic6x_unwind_table_edit **head,
+				   tic6x_unwind_table_edit **tail,
+				   tic6x_unwind_edit_type type,
+				   asection *linked_section,
+				   unsigned int tindex)
+{
+  tic6x_unwind_table_edit *new_edit = (tic6x_unwind_table_edit *)
+      xmalloc (sizeof (tic6x_unwind_table_edit));
+  
+  new_edit->type = type;
+  new_edit->linked_section = linked_section;
+  new_edit->index = tindex;
+  
+  if (tindex > 0)
+    {
+      new_edit->next = NULL;
+
+      if (*tail)
+	(*tail)->next = new_edit;
+
+      (*tail) = new_edit;
+
+      if (!*head)
+	(*head) = new_edit;
+    }
+  else
+    {
+      new_edit->next = *head;
+
+      if (!*tail)
+	*tail = new_edit;
+
+      *head = new_edit;
+    }
+}
+
+static _tic6x_elf_section_data *
+get_tic6x_elf_section_data (asection * sec)
+{
+  if (sec && sec->owner && is_tic6x_elf (sec->owner))
+    return elf32_tic6x_section_data (sec);
+  else
+    return NULL;
+}
+
+
+/* Increase the size of EXIDX_SEC by ADJUST bytes.  ADJUST must be negative.  */
+static void
+elf32_tic6x_adjust_exidx_size (asection *exidx_sec, int adjust)
+{
+  asection *out_sec;
+
+  if (!exidx_sec->rawsize)
+    exidx_sec->rawsize = exidx_sec->size;
+
+  bfd_set_section_size (exidx_sec->owner, exidx_sec, exidx_sec->size + adjust);
+  out_sec = exidx_sec->output_section;
+  /* Adjust size of output section.  */
+  bfd_set_section_size (out_sec->owner, out_sec, out_sec->size +adjust);
+}
+
+/* Insert an EXIDX_CANTUNWIND marker at the end of a section.  */
+static void
+elf32_tic6x_insert_cantunwind_after (asection *text_sec, asection *exidx_sec)
+{
+  struct _tic6x_elf_section_data *exidx_data;
+
+  exidx_data = get_tic6x_elf_section_data (exidx_sec);
+  elf32_tic6x_add_unwind_table_edit (
+    &exidx_data->u.exidx.unwind_edit_list,
+    &exidx_data->u.exidx.unwind_edit_tail,
+    INSERT_EXIDX_CANTUNWIND_AT_END, text_sec, UINT_MAX);
+
+  elf32_tic6x_adjust_exidx_size (exidx_sec, 8);
+}
+
+/* Scan .cx6abi.exidx tables, and create a list describing edits which
+   should be made to those tables, such that:
+   
+     1. Regions without unwind data are marked with EXIDX_CANTUNWIND entries.
+     2. Duplicate entries are merged together (EXIDX_CANTUNWIND, or unwind
+        codes which have been inlined into the index).
+
+   If MERGE_EXIDX_ENTRIES is false, duplicate entries are not merged.
+
+   The edits are applied when the tables are written
+   (in elf32_tic6x_write_section).
+*/
+
+bfd_boolean
+elf32_tic6x_fix_exidx_coverage (asection **text_section_order,
+				unsigned int num_text_sections,
+				struct bfd_link_info *info,
+				bfd_boolean merge_exidx_entries)
+{
+  bfd *inp;
+  unsigned int last_second_word = 0, i;
+  asection *last_exidx_sec = NULL;
+  asection *last_text_sec = NULL;
+  int last_unwind_type = -1;
+
+  /* Walk over all EXIDX sections, and create backlinks from the corrsponding
+     text sections.  */
+  for (inp = info->input_bfds; inp != NULL; inp = inp->link_next)
+    {
+      asection *sec;
+      
+      for (sec = inp->sections; sec != NULL; sec = sec->next)
+        {
+	  struct bfd_elf_section_data *elf_sec = elf_section_data (sec);
+	  Elf_Internal_Shdr *hdr = &elf_sec->this_hdr;
+	  
+	  if (!hdr || hdr->sh_type != SHT_C6000_UNWIND)
+	    continue;
+	  
+	  if (elf_sec->linked_to)
+	    {
+	      Elf_Internal_Shdr *linked_hdr
+	        = &elf_section_data (elf_sec->linked_to)->this_hdr;
+	      struct _tic6x_elf_section_data *linked_sec_tic6x_data
+	        = get_tic6x_elf_section_data (linked_hdr->bfd_section);
+
+	      if (linked_sec_tic6x_data == NULL)
+	        continue;
+
+	      /* Link this .c6xabi.exidx section back from the
+		 text section it describes.  */
+	      linked_sec_tic6x_data->u.text.tic6x_exidx_sec = sec;
+	    }
+	}
+    }
+
+  /* Walk all text sections in order of increasing VMA.  Eilminate duplicate
+     index table entries (EXIDX_CANTUNWIND and inlined unwind opcodes),
+     and add EXIDX_CANTUNWIND entries for sections with no unwind table data.  */
+
+  for (i = 0; i < num_text_sections; i++)
+    {
+      asection *sec = text_section_order[i];
+      asection *exidx_sec;
+      struct _tic6x_elf_section_data *tic6x_data
+       	= get_tic6x_elf_section_data (sec);
+      struct _tic6x_elf_section_data *exidx_data;
+      bfd_byte *contents = NULL;
+      int deleted_exidx_bytes = 0;
+      bfd_vma j;
+      tic6x_unwind_table_edit *unwind_edit_head = NULL;
+      tic6x_unwind_table_edit *unwind_edit_tail = NULL;
+      Elf_Internal_Shdr *hdr;
+      bfd *ibfd;
+
+      if (tic6x_data == NULL)
+        continue;
+
+      exidx_sec = tic6x_data->u.text.tic6x_exidx_sec;
+      if (exidx_sec == NULL)
+	{
+	  /* Section has no unwind data.  */
+	  if (last_unwind_type == 0 || !last_exidx_sec)
+	    continue;
+
+	  /* Ignore zero sized sections.  */
+	  if (sec->size == 0)
+	    continue;
+
+	  elf32_tic6x_insert_cantunwind_after (last_text_sec, last_exidx_sec);
+	  last_unwind_type = 0;
+	  continue;
+	}
+
+      /* Skip /DISCARD/ sections.  */
+      if (bfd_is_abs_section (exidx_sec->output_section))
+	continue;
+
+      hdr = &elf_section_data (exidx_sec)->this_hdr;
+      if (hdr->sh_type != SHT_C6000_UNWIND)
+        continue;
+      
+      exidx_data = get_tic6x_elf_section_data (exidx_sec);
+      if (exidx_data == NULL)
+        continue;
+      
+      ibfd = exidx_sec->owner;
+	  
+      if (hdr->contents != NULL)
+	contents = hdr->contents;
+      else if (! bfd_malloc_and_get_section (ibfd, exidx_sec, &contents))
+	/* An error?  */
+	continue;
+
+      for (j = 0; j < hdr->sh_size; j += 8)
+	{
+	  unsigned int second_word = bfd_get_32 (ibfd, contents + j + 4);
+	  int unwind_type;
+	  int elide = 0;
+
+	  /* An EXIDX_CANTUNWIND entry.  */
+	  if (second_word == 1)
+	    {
+	      if (last_unwind_type == 0)
+		elide = 1;
+	      unwind_type = 0;
+	    }
+	  /* Inlined unwinding data.  Merge if equal to previous.  */
+	  else if ((second_word & 0x80000000) != 0)
+	    {
+	      if (merge_exidx_entries
+		  && last_second_word == second_word
+		  && last_unwind_type == 1)
+		elide = 1;
+	      unwind_type = 1;
+	      last_second_word = second_word;
+	    }
+	  /* Normal table entry.  In theory we could merge these too,
+	     but duplicate entries are likely to be much less common.  */
+	  else
+	    unwind_type = 2;
+
+	  if (elide)
+	    {
+	      elf32_tic6x_add_unwind_table_edit (&unwind_edit_head,
+		  &unwind_edit_tail, DELETE_EXIDX_ENTRY, NULL, j / 8);
+
+	      deleted_exidx_bytes += 8;
+	    }
+
+	  last_unwind_type = unwind_type;
+	}
+
+      /* Free contents if we allocated it ourselves.  */
+      if (contents != hdr->contents)
+        free (contents);
+
+      /* Record edits to be applied later (in elf32_tic6x_write_section).  */
+      exidx_data->u.exidx.unwind_edit_list = unwind_edit_head;
+      exidx_data->u.exidx.unwind_edit_tail = unwind_edit_tail;
+	  
+      if (deleted_exidx_bytes > 0)
+	elf32_tic6x_adjust_exidx_size (exidx_sec, -deleted_exidx_bytes);
+
+      last_exidx_sec = exidx_sec;
+      last_text_sec = sec;
+    }
+
+  /* Add terminating CANTUNWIND entry.  */
+  if (last_exidx_sec && last_unwind_type != 0)
+    elf32_tic6x_insert_cantunwind_after (last_text_sec, last_exidx_sec);
+
+  return TRUE;
+}
+
+/* Add ADDEND to lower 31 bits of VAL, leaving other bits unmodified.  */
+
+static unsigned long
+elf32_tic6x_add_low31 (unsigned long val, bfd_vma addend)
+{
+  return (val & ~0x7ffffffful) | ((val + addend) & 0x7ffffffful);
+}
+
+/* Copy an .c6xabi.exidx table entry, adding OFFSET to (applied) PREL31
+   relocations.  OFFSET is in bytes, and will be scaled before encoding.  */
+
+
+static void
+elf32_tic6x_copy_exidx_entry (bfd *output_bfd, bfd_byte *to, bfd_byte *from,
+			      bfd_vma offset)
+{
+  unsigned long first_word = bfd_get_32 (output_bfd, from);
+  unsigned long second_word = bfd_get_32 (output_bfd, from + 4);
+
+  offset >>= 1;
+  /* High bit of first word is supposed to be zero.  */
+  if ((first_word & 0x80000000ul) == 0)
+    first_word = elf32_tic6x_add_low31 (first_word, offset);
+  
+  /* If the high bit of the first word is clear, and the bit pattern is not 0x1
+     (EXIDX_CANTUNWIND), this is an offset to an .c6xabi.extab entry.  */
+  if ((second_word != 0x1) && ((second_word & 0x80000000ul) == 0))
+    second_word = elf32_tic6x_add_low31 (second_word, offset);
+  
+  bfd_put_32 (output_bfd, first_word, to);
+  bfd_put_32 (output_bfd, second_word, to + 4);
+}
+
+/* Do the actual mangling of exception index tables.  */
+
+static bfd_boolean
+elf32_tic6x_write_section (bfd *output_bfd,
+			 struct bfd_link_info *link_info,
+			 asection *sec,
+			 bfd_byte *contents)
+{
+  _tic6x_elf_section_data *tic6x_data;
+  struct elf32_tic6x_link_hash_table *globals
+    = elf32_tic6x_hash_table (link_info);
+  bfd_vma offset = sec->output_section->vma + sec->output_offset;
+
+  if (globals == NULL)
+    return FALSE;
+
+  /* If this section has not been allocated an _tic6x_elf_section_data
+     structure then we cannot record anything.  */
+  tic6x_data = get_tic6x_elf_section_data (sec);
+  if (tic6x_data == NULL)
+    return FALSE;
+
+  if (tic6x_data->elf.this_hdr.sh_type != SHT_C6000_UNWIND)
+    return FALSE;
+
+  tic6x_unwind_table_edit *edit_node
+    = tic6x_data->u.exidx.unwind_edit_list;
+  /* Now, sec->size is the size of the section we will write.  The original
+     size (before we merged duplicate entries and inserted EXIDX_CANTUNWIND
+     markers) was sec->rawsize.  (This isn't the case if we perform no
+     edits, then rawsize will be zero and we should use size).  */
+  bfd_byte *edited_contents = (bfd_byte *) bfd_malloc (sec->size);
+  unsigned int input_size = sec->rawsize ? sec->rawsize : sec->size;
+  unsigned int in_index, out_index;
+  bfd_vma add_to_offsets = 0;
+
+  for (in_index = 0, out_index = 0; in_index * 8 < input_size || edit_node;)
+    {
+      if (edit_node)
+	{
+	  unsigned int edit_index = edit_node->index;
+	  
+	  if (in_index < edit_index && in_index * 8 < input_size)
+	    {
+	      elf32_tic6x_copy_exidx_entry (output_bfd,
+		  edited_contents + out_index * 8,
+		  contents + in_index * 8, add_to_offsets);
+	      out_index++;
+	      in_index++;
+	    }
+	  else if (in_index == edit_index
+		   || (in_index * 8 >= input_size
+		       && edit_index == UINT_MAX))
+	    {
+	      switch (edit_node->type)
+		{
+		case DELETE_EXIDX_ENTRY:
+		  in_index++;
+		  add_to_offsets += 8;
+		  break;
+		
+		case INSERT_EXIDX_CANTUNWIND_AT_END:
+		  {
+		    asection *text_sec = edit_node->linked_section;
+		    bfd_vma text_offset = text_sec->output_section->vma
+					  + text_sec->output_offset
+					  + text_sec->size;
+		    bfd_vma exidx_offset = offset + out_index * 8;
+		    unsigned long prel31_offset;
+
+		    /* Note: this is meant to be equivalent to an
+		       R_C6000_PREL31 relocation.  These synthetic
+		       EXIDX_CANTUNWIND markers are not relocated by the
+		       usual BFD method.  */
+		    prel31_offset = ((text_offset - exidx_offset) >> 1)
+				    & 0x7ffffffful;
+
+		    /* First address we can't unwind.  */
+		    bfd_put_32 (output_bfd, prel31_offset,
+				&edited_contents[out_index * 8]);
+
+		    /* Code for EXIDX_CANTUNWIND.  */
+		    bfd_put_32 (output_bfd, 0x1,
+				&edited_contents[out_index * 8 + 4]);
+
+		    out_index++;
+		    add_to_offsets -= 8;
+		  }
+		  break;
+		}
+	      
+	      edit_node = edit_node->next;
+	    }
+	}
+      else
+	{
+	  /* No more edits, copy remaining entries verbatim.  */
+	  elf32_tic6x_copy_exidx_entry (output_bfd,
+	      edited_contents + out_index * 8,
+	      contents + in_index * 8, add_to_offsets);
+	  out_index++;
+	  in_index++;
+	}
+    }
+
+  if (!(sec->flags & SEC_EXCLUDE) && !(sec->flags & SEC_NEVER_LOAD))
+    bfd_set_section_contents (output_bfd, sec->output_section,
+			      edited_contents,
+			      (file_ptr) sec->output_offset, sec->size);
+
+  return TRUE;
+}
+
 #define TARGET_LITTLE_SYM	bfd_elf32_tic6x_le_vec
 #define TARGET_LITTLE_NAME	"elf32-tic6x-le"
 #define TARGET_BIG_SYM		bfd_elf32_tic6x_be_vec
@@ -4036,6 +4498,7 @@ elf32_tic6x_copy_private_data (bfd * ibfd, bfd * obfd)
   elf32_tic6x_finish_dynamic_sections
 #define bfd_elf32_bfd_final_link \
 	elf32_tic6x_final_link
+#define elf_backend_write_section	elf32_tic6x_write_section
 #define elf_info_to_howto		elf32_tic6x_info_to_howto
 #define elf_info_to_howto_rel		elf32_tic6x_info_to_howto_rel
 
diff --git a/ld/ChangeLog b/ld/ChangeLog
index b2fe365b83c..e7e526b603d 100644
--- a/ld/ChangeLog
+++ b/ld/ChangeLog
@@ -1,3 +1,14 @@
+2011-05-09  Paul Brook  <paul@codesourcery.com>
+
+	* emultempl/tic6xdsbt.em (merge_exidx_entries): New.
+	(compare_output_sec_vma): New function.
+	(gld${EMULATION_NAME}_after_allocation): New function.
+	(OPTION_NO_MERGE_EXIDX_ENTRIES): Define.
+	(PARSE_AND_LIST_OPTIONS): Add --no-merge-exidx-entries.
+	(PARSE_AND_LIST_ARGS_CASES): Add OPTION_NO_MERGE_EXIDX_ENTRIES.
+	(LDEMUL_AFTER_ALLOCATION): Set.
+	* ld.texinfo: Document c6x --no-merge-exidx-entries.
+
 2011-05-07  Dave Korn  <dave.korn.cygwin@gmail.com>
 
 	PR ld/12365
diff --git a/ld/emultempl/tic6xdsbt.em b/ld/emultempl/tic6xdsbt.em
index 875148e2f96..d0e345d20e8 100644
--- a/ld/emultempl/tic6xdsbt.em
+++ b/ld/emultempl/tic6xdsbt.em
@@ -31,6 +31,8 @@ static struct elf32_tic6x_params params =
   0, 64
 };
 
+static int merge_exidx_entries = -1;
+
 static int
 is_tic6x_target (void)
 {
@@ -58,6 +60,92 @@ tic6x_after_open (void)
 
   gld${EMULATION_NAME}_after_open ();
 }
+
+static int
+compare_output_sec_vma (const void *a, const void *b)
+{
+  asection *asec = *(asection **) a, *bsec = *(asection **) b;
+  asection *aout = asec->output_section, *bout = bsec->output_section;
+  bfd_vma avma, bvma;
+  
+  /* If there's no output section for some reason, compare equal.  */
+  if (!aout || !bout)
+    return 0;
+  
+  avma = aout->vma + asec->output_offset;
+  bvma = bout->vma + bsec->output_offset;
+  
+  if (avma > bvma)
+    return 1;
+  else if (avma < bvma)
+    return -1;
+  
+  return 0;
+}
+
+static void
+gld${EMULATION_NAME}_after_allocation (void)
+{
+  int layout_changed = 0;
+
+  if (!link_info.relocatable)
+    {
+      /* Build a sorted list of input text sections, then use that to process
+	 the unwind table index.  */
+      unsigned int list_size = 10;
+      asection **sec_list = (asection **)
+          xmalloc (list_size * sizeof (asection *));
+      unsigned int sec_count = 0;
+
+      LANG_FOR_EACH_INPUT_STATEMENT (is)
+	{
+	  bfd *abfd = is->the_bfd;
+	  asection *sec;
+	  
+	  if ((abfd->flags & (EXEC_P | DYNAMIC)) != 0)
+	    continue;
+	  
+	  for (sec = abfd->sections; sec != NULL; sec = sec->next)
+	    {
+	      asection *out_sec = sec->output_section;
+
+	      if (out_sec
+		  && elf_section_data (sec)
+		  && elf_section_type (sec) == SHT_PROGBITS
+		  && (elf_section_flags (sec) & SHF_EXECINSTR) != 0
+		  && (sec->flags & SEC_EXCLUDE) == 0
+		  && sec->sec_info_type != ELF_INFO_TYPE_JUST_SYMS
+		  && out_sec != bfd_abs_section_ptr)
+		{
+		  if (sec_count == list_size)
+		    {
+		      list_size *= 2;
+		      sec_list = (asection **) 
+                          xrealloc (sec_list, list_size * sizeof (asection *));
+		    }
+
+		  sec_list[sec_count++] = sec;
+		}
+	    }
+	}
+	
+      qsort (sec_list, sec_count, sizeof (asection *), &compare_output_sec_vma);
+      
+      if (elf32_tic6x_fix_exidx_coverage (sec_list, sec_count, &link_info,
+					   merge_exidx_entries))
+	layout_changed = 1;
+      
+      free (sec_list);
+    }
+
+  /* bfd_elf32_discard_info just plays with debugging sections,
+     ie. doesn't affect any code, so we can delay resizing the
+     sections.  */
+  if (bfd_elf_discard_info (link_info.output_bfd, & link_info))
+    layout_changed = 1;
+
+  gld${EMULATION_NAME}_map_segments (layout_changed);
+}
 EOF
 
 # This code gets inserted into the generic elf32.sc linker script
@@ -65,11 +153,13 @@ EOF
 PARSE_AND_LIST_PROLOGUE='
 #define OPTION_DSBT_INDEX		300
 #define OPTION_DSBT_SIZE		301
+#define OPTION_NO_MERGE_EXIDX_ENTRIES   302
 '
 
 PARSE_AND_LIST_LONGOPTS='
   {"dsbt-index", required_argument, NULL, OPTION_DSBT_INDEX},
   {"dsbt-size", required_argument, NULL, OPTION_DSBT_SIZE},
+  { "no-merge-exidx-entries", no_argument, NULL, OPTION_NO_MERGE_EXIDX_ENTRIES },
 '
 
 PARSE_AND_LIST_OPTIONS='
@@ -77,6 +167,7 @@ PARSE_AND_LIST_OPTIONS='
   fprintf (file, _("\t\t\tUse this as the DSBT index for the output object\n"));
   fprintf (file, _("  --dsbt-size <index>\n"));
   fprintf (file, _("\t\t\tUse this as the number of entries in the DSBT table\n"));
+  fprintf (file, _("  --no-merge-exidx-entries    Disable merging exidx entries\n"));
 '
 
 PARSE_AND_LIST_ARGS_CASES='
@@ -100,6 +191,9 @@ PARSE_AND_LIST_ARGS_CASES='
 	einfo (_("%P%F: invalid --dsbt-size %s\n"), optarg);
       }
       break;
+   case OPTION_NO_MERGE_EXIDX_ENTRIES:
+      merge_exidx_entries = 0;
 '
 
 LDEMUL_AFTER_OPEN=tic6x_after_open
+LDEMUL_AFTER_ALLOCATION=gld${EMULATION_NAME}_after_allocation
diff --git a/ld/ld.texinfo b/ld/ld.texinfo
index 800f0d46fdd..0b583960195 100644
--- a/ld/ld.texinfo
+++ b/ld/ld.texinfo
@@ -2637,6 +2637,10 @@ to @var{index}.  The default is 0, which is appropriate for generating
 executables.  If a shared library is generated with a DSBT index of 0, the
 @code{R_C6000_DSBT_INDEX} relocs are copied into the output file.
 
+@kindex --no-merge-exidx-entries
+The @samp{--no-merge-exidx-entries} switch disables the merging of adjacent
+exidx entries in frame unwind info.
+
 @end table
 
 @c man end
diff --git a/ld/testsuite/ChangeLog b/ld/testsuite/ChangeLog
index 02581cccb6a..6ef59198043 100644
--- a/ld/testsuite/ChangeLog
+++ b/ld/testsuite/ChangeLog
@@ -1,3 +1,19 @@
+2011-05-09  Paul Brook  <paul@codesourcery.com>
+
+	* ld-tic6x/discard-unwind.ld: New.
+	* ld-tic6x/unwind.ld: New.
+	* ld-tic6x/unwind-1.d: New test.
+	* ld-tic6x/unwind-1.s: New test.
+	* ld-tic6x/unwind-2.d: New test.
+	* ld-tic6x/unwind-2.s: New test.
+	* ld-tic6x/unwind-3.d: New test.
+	* ld-tic6x/unwind-3.s: New test.
+	* ld-tic6x/unwind-4.d: New test.
+	* ld-tic6x/unwind-4.s: New test.
+	* ld-tic6x/unwind-5.d: New test.
+	* ld-tic6x/unwind-5.s: New test.
+	* ld-tic6x/unwind-6.d: New test.
+
 2011-05-07  Dave Korn  <dave.korn.cygwin@gmail.com>
 
 	PR ld/12365
diff --git a/ld/testsuite/ld-tic6x/discard-unwind.ld b/ld/testsuite/ld-tic6x/discard-unwind.ld
new file mode 100644
index 00000000000..00582c1e7b7
--- /dev/null
+++ b/ld/testsuite/ld-tic6x/discard-unwind.ld
@@ -0,0 +1,15 @@
+/* Script for unwinding ld tests */
+SECTIONS
+{
+  /* Read-only sections, merged into text segment: */
+  . = 0x8000;
+  .text           :
+  {
+    *(.before)
+    *(.text)
+    *(.after)
+    *(.c6xabi.extab*)
+  } =0
+  /DISCARD/ : { *(.c6xabi.exidx*) }
+  .c6xabi.attribues 0 : { *(.c6xabi.atttributes) }
+}
diff --git a/ld/testsuite/ld-tic6x/unwind-1.d b/ld/testsuite/ld-tic6x/unwind-1.d
new file mode 100644
index 00000000000..11a24d4a0b9
--- /dev/null
+++ b/ld/testsuite/ld-tic6x/unwind-1.d
@@ -0,0 +1,10 @@
+#ld: -T unwind.ld
+#objdump: -s
+
+.*:     file format.*
+
+#...
+Contents of section .c6xabi.exidx:
+ 9000 (00f8ff7f 07020083 1cf8ff7f 01000000|7ffff800 83000207 7ffff81c 00000001)  .*
+Contents of section .far:
+#...
diff --git a/ld/testsuite/ld-tic6x/unwind-1.s b/ld/testsuite/ld-tic6x/unwind-1.s
new file mode 100644
index 00000000000..5783a401615
--- /dev/null
+++ b/ld/testsuite/ld-tic6x/unwind-1.s
@@ -0,0 +1,25 @@
+	.cfi_sections .c6xabi.exidx
+	.text
+	.global _start
+	.type _start, %function
+_start:
+	.cfi_startproc
+	.cfi_offset B3, 0
+	.cfi_def_cfa_offset 8
+	nop
+	.p2align 6
+	.cfi_endproc
+	.personalityindex 3
+	.endp
+
+	# Section with no unwinding information.
+	# Linker should insert a cantunwind entry.
+	.section .after, "xa"
+	.global __c6xabi_unwind_cpp_pr3
+	.type __c6xabi_unwind_cpp_pr3, %function
+__c6xabi_unwind_cpp_pr3:
+	nop
+	.p2align 6
+
+	.section .far
+	.word 0
diff --git a/ld/testsuite/ld-tic6x/unwind-2.d b/ld/testsuite/ld-tic6x/unwind-2.d
new file mode 100644
index 00000000000..11a24d4a0b9
--- /dev/null
+++ b/ld/testsuite/ld-tic6x/unwind-2.d
@@ -0,0 +1,10 @@
+#ld: -T unwind.ld
+#objdump: -s
+
+.*:     file format.*
+
+#...
+Contents of section .c6xabi.exidx:
+ 9000 (00f8ff7f 07020083 1cf8ff7f 01000000|7ffff800 83000207 7ffff81c 00000001)  .*
+Contents of section .far:
+#...
diff --git a/ld/testsuite/ld-tic6x/unwind-2.s b/ld/testsuite/ld-tic6x/unwind-2.s
new file mode 100644
index 00000000000..dbfd3bdeb15
--- /dev/null
+++ b/ld/testsuite/ld-tic6x/unwind-2.s
@@ -0,0 +1,23 @@
+	.cfi_sections .c6xabi.exidx
+	.text
+
+	.global __c6xabi_unwind_cpp_pr3
+	.type __c6xabi_unwind_cpp_pr3, %function
+__c6xabi_unwind_cpp_pr3:
+	.global _start
+	.type _start, %function
+_start:
+	.cfi_startproc
+	.cfi_offset B3, 0
+	.cfi_def_cfa_offset 8
+	nop
+	.p2align 6
+	.cfi_endproc
+	.personalityindex 3
+	.endp
+
+	# last text section has unwind information. Linker should append a
+	# terminating cantunwind entry.
+
+	.section .far
+	.word 0
diff --git a/ld/testsuite/ld-tic6x/unwind-3.d b/ld/testsuite/ld-tic6x/unwind-3.d
new file mode 100644
index 00000000000..9ec69a0aaa9
--- /dev/null
+++ b/ld/testsuite/ld-tic6x/unwind-3.d
@@ -0,0 +1,11 @@
+#ld: -T unwind.ld
+#objdump: -s
+
+.*:     file format.*
+
+#...
+Contents of section .c6xabi.exidx:
+ 9000 (00f8ff7f 07020083 1cf8ff7f 01000000|7ffff800 83000207 7ffff81c 00000001)  .*
+ 9010 (38f8ff7f 07040083 54f8ff7f 01000000|7ffff838 82000407 7ffff854 00000001)  .*
+Contents of section .far:
+#...
diff --git a/ld/testsuite/ld-tic6x/unwind-3.s b/ld/testsuite/ld-tic6x/unwind-3.s
new file mode 100644
index 00000000000..480ee49d26f
--- /dev/null
+++ b/ld/testsuite/ld-tic6x/unwind-3.s
@@ -0,0 +1,39 @@
+	.cfi_sections .c6xabi.exidx
+	.text
+	# section without unwind info
+	.global _start
+	.type _start, %function
+_start:
+	b .s2 _before
+	nop 5
+	.p2align 6
+
+	# Section that will be placed first
+	.section .before, "xa"
+	.type _before, %function
+_before:
+	.cfi_startproc
+	.cfi_offset B3, 0
+	.cfi_def_cfa_offset 8
+	nop
+	.p2align 6
+	.cfi_endproc
+	.personalityindex 3
+	.endp
+
+	# section that will be placed last
+	.section .after, "xa"
+	.global __c6xabi_unwind_cpp_pr3
+	.type __c6xabi_unwind_cpp_pr3, %function
+__c6xabi_unwind_cpp_pr3:
+	.cfi_startproc
+	.cfi_offset B10, 0
+	.cfi_def_cfa_offset 8
+	nop
+	.p2align 6
+	.cfi_endproc
+	.personalityindex 3
+	.endp
+
+	.section .far
+	.word 0
diff --git a/ld/testsuite/ld-tic6x/unwind-4.d b/ld/testsuite/ld-tic6x/unwind-4.d
new file mode 100644
index 00000000000..e5c628ef5f2
--- /dev/null
+++ b/ld/testsuite/ld-tic6x/unwind-4.d
@@ -0,0 +1,11 @@
+#ld: -T unwind.ld
+#objdump: -s
+
+.*:     file format.*
+
+#...
+Contents of section .c6xabi.exidx:
+ 9000 (00f8ff7f 07020083 1cf8ff7f 7af8ff7f|7ffff800 83000207 7ffff81c 7ffff87a)  .*
+ 9010 (38f8ff7f 07020083 56f8ff7f 01000000|7ffff838 83000207 7ffff856 00000001)  .*
+Contents of section .far:
+#...
diff --git a/ld/testsuite/ld-tic6x/unwind-4.s b/ld/testsuite/ld-tic6x/unwind-4.s
new file mode 100644
index 00000000000..83f3d0d78d6
--- /dev/null
+++ b/ld/testsuite/ld-tic6x/unwind-4.s
@@ -0,0 +1,68 @@
+	.cfi_sections .c6xabi.exidx
+	.text
+	# out of line table entry
+	.global _start
+	.type _start, %function
+_start:
+	.cfi_startproc
+	.cfi_offset B3, 0
+	.cfi_def_cfa_offset 8
+	nop
+	.p2align 6
+	.cfi_endproc
+	.personalityindex 3
+	.handlerdata
+	.word 0
+	.endp
+
+	# entry that can be merged
+	.cfi_startproc
+	.cfi_offset B3, 0
+	.cfi_def_cfa_offset 8
+	nop
+	.p2align 6
+	.cfi_endproc
+	.personalityindex 3
+	.endp
+
+	# Section that will be placed first
+	.section .before, "xa"
+	.type _before, %function
+_before:
+	.cfi_startproc
+	.cfi_offset B3, 0
+	.cfi_def_cfa_offset 8
+	nop
+	.p2align 6
+	.cfi_endproc
+	.personalityindex 3
+	.endp
+
+	# section that will be placed last
+	.section .after, "xa"
+	.global __c6xabi_unwind_cpp_pr3
+	.type __c6xabi_unwind_cpp_pr3, %function
+__c6xabi_unwind_cpp_pr3:
+	# entry that can be merged
+	.cfi_startproc
+	.cfi_offset B3, 0
+	.cfi_def_cfa_offset 8
+	nop
+	.cfi_endproc
+	.personalityindex 3
+	.endp
+
+	# final function is cantunwind, so output table size is smaller
+	# than sum of input sections
+	.global foo
+	.type foo, %function
+foo:
+	.cfi_startproc
+	nop
+	.p2align 6
+	.cfi_endproc
+	.cantunwind
+	.endp
+
+	.section .far
+	.word 0
diff --git a/ld/testsuite/ld-tic6x/unwind-5.d b/ld/testsuite/ld-tic6x/unwind-5.d
new file mode 100644
index 00000000000..492887415ce
--- /dev/null
+++ b/ld/testsuite/ld-tic6x/unwind-5.d
@@ -0,0 +1,7 @@
+#ld: -T discard-unwind.ld
+#objdump: -s
+
+.*:     file format.*
+
+# Check we don't crash when discarding unwind info.
+#...
diff --git a/ld/testsuite/ld-tic6x/unwind-5.s b/ld/testsuite/ld-tic6x/unwind-5.s
new file mode 100644
index 00000000000..b4fc2133647
--- /dev/null
+++ b/ld/testsuite/ld-tic6x/unwind-5.s
@@ -0,0 +1,16 @@
+	.cfi_sections .c6xabi.exidx
+	.text
+	.global __c6xabi_unwind_cpp_pr3
+	.type __c6xabi_unwind_cpp_pr3, %function
+__c6xabi_unwind_cpp_pr3:
+	.global _start
+	.type _start, %function
+_start:
+	.cfi_startproc
+	.cfi_offset B3, 0
+	.cfi_def_cfa_offset 8
+	nop
+	.p2align 6
+	.cfi_endproc
+	.personalityindex 3
+	.endp
diff --git a/ld/testsuite/ld-tic6x/unwind-6.d b/ld/testsuite/ld-tic6x/unwind-6.d
new file mode 100644
index 00000000000..5de8ee6d567
--- /dev/null
+++ b/ld/testsuite/ld-tic6x/unwind-6.d
@@ -0,0 +1,13 @@
+#ld: -T unwind.ld
+#source unwind-4.s
+#as: -mgenerate-rel
+#objdump: -s
+
+.*:     file format.*
+
+#...
+Contents of section .c6xabi.exidx:
+ 9000 (00f8ff7f 07020083 1cf8ff7f 7af8ff7f|7ffff800 83000207 7ffff81c 7ffff87a)  .*
+ 9010 (38f8ff7f 07020083 56f8ff7f 01000000|7ffff838 83000207 7ffff856 00000001)  .*
+Contents of section .far:
+#...
diff --git a/ld/testsuite/ld-tic6x/unwind.ld b/ld/testsuite/ld-tic6x/unwind.ld
new file mode 100644
index 00000000000..a4f87229f49
--- /dev/null
+++ b/ld/testsuite/ld-tic6x/unwind.ld
@@ -0,0 +1,20 @@
+/* Script for unwinding ld tests */
+SECTIONS
+{
+  /* Read-only sections, merged into text segment: */
+  . = 0x8000;
+  .text           :
+  {
+    *(.before)
+    *(.text)
+    *(.after)
+    *(.c6xabi.extab*)
+  } =0
+  . = 0x9000;
+  .c6xabi.exidx : { *(.c6xabi.exidx*) }
+  . = 0xa000;
+  .got            : { *(.got) *(.got.plt)}
+  . = 0x12340000;
+  .far : { *(.far) }
+  .c6xabi.attribues 0 : { *(.c6xabi.atttributes) }
+}