Attachment 7330 Details for Bug 16345 – Patch

[patch] Patch

eh_frame-unordered-relocs.patch (text/plain), 7.39 KB, created by Alexey Neyman on 2013-12-18 21:44:25 UTC

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Creator: Alexey Neyman

Created: 2013-12-18 21:44:25 UTC

Size: 7.39 KB

patch

obsolete

>From 63984be23dee3df45590f25e176ce4985691ebb3 Mon Sep 17 00:00:00 2001
>From: Alexey Neyman <stilor@att.net>
>Date: Wed, 18 Dec 2013 12:11:29 -0800
>Subject: [PATCH] Allow .eh_frame reader to cope with unordered relocations
>
>Unordered relocations can result from partial linking of file with different
>text sections (e.g., .text and .init).
>---
> bfd/elf-eh-frame.c | 149 +++++++++++++++++++++++++++++++++++++++++++++--------
> 1 file changed, 127 insertions(+), 22 deletions(-)
>
>diff --git a/bfd/elf-eh-frame.c b/bfd/elf-eh-frame.c
>index 832a991..2457c4f 100644
>--- a/bfd/elf-eh-frame.c
>+++ b/bfd/elf-eh-frame.c
>@@ -457,6 +457,107 @@ _bfd_elf_begin_eh_frame_parsing (struct bfd_link_info *info)
>   hdr_info->merge_cies = !info->relocatable;
> }
> 
>+struct reloc_read_ops
>+{
>+  Elf_Internal_Rela * (*chk_relocs) (struct elf_reloc_cookie *,
>+      bfd_vma, bfd_vma);
>+  Elf_Internal_Rela * (*get_reloc) (struct elf_reloc_cookie *, bfd_vma);
>+  void (*skip_relocs) (struct elf_reloc_cookie *, bfd_vma, bfd_vma *);
>+};
>+
>+/* Implementation of the ENSURE_NO_RELOCS macro for ordered relocations. */
>+static Elf_Internal_Rela *
>+_bfd_chk_relocs_ordered (struct elf_reloc_cookie *cookie,
>+			 bfd_vma rels_offset ATTRIBUTE_UNUSED,
>+			 bfd_vma offset)
>+{
>+  /* FIXME: octets_per_byte.  */
>+  if (cookie->rel < cookie->relend
>+      && cookie->rel->r_offset < offset
>+      && cookie->rel->r_info != 0)
>+    return cookie->rel;
>+  return NULL;
>+}
>+
>+/* Implementation of the GET_RELOC macro for ordered relocations. */
>+static Elf_Internal_Rela *
>+_bfd_get_reloc_ordered (struct elf_reloc_cookie *cookie, bfd_vma offset)
>+{
>+  /* FIXME: octets_per_byte.  */
>+  return cookie->rel < cookie->relend && cookie->rel->r_offset == offset
>+    ? cookie->rel : NULL;
>+}
>+
>+/* Implementation of the SKIP_RELOCS macro for ordered relocations. */
>+static void
>+_bfd_skip_relocs_ordered (struct elf_reloc_cookie *cookie, bfd_vma offset,
>+			  bfd_vma *rels_offset ATTRIBUTE_UNUSED)
>+{
>+  /* FIXME: octets_per_byte.  */
>+  while (cookie->rel < cookie->relend && cookie->rel->r_offset < offset)
>+    cookie->rel++;
>+}
>+
>+static struct reloc_read_ops _bfd_eh_ordered_relocs = {
>+  .chk_relocs = _bfd_chk_relocs_ordered,
>+  .get_reloc = _bfd_get_reloc_ordered,
>+  .skip_relocs = _bfd_skip_relocs_ordered,
>+};
>+
>+/* Implementation of the ENSURE_NO_RELOCS macro for unordered relocations. */
>+static Elf_Internal_Rela *
>+_bfd_chk_relocs_unordered (struct elf_reloc_cookie *cookie,
>+			   bfd_vma rels_offset, bfd_vma offset)
>+{
>+  Elf_Internal_Rela *rel;
>+
>+  /* FIXME: octets_per_byte.  */
>+  for (rel = cookie->rels; rel < cookie->relend; rel++)
>+    if (rel->r_offset >= rels_offset
>+	&& rel->r_offset < offset
>+	&& rel->r_info != 0)
>+      return rel;
>+  return NULL;
>+}
>+
>+/* Implementation of the GET_RELOC macro for unordered relocations. */
>+static Elf_Internal_Rela *
>+_bfd_get_reloc_unordered (struct elf_reloc_cookie *cookie, bfd_vma offset)
>+{
>+  Elf_Internal_Rela *rel;
>+
>+  /* FIXME: octets_per_byte.  */
>+  for (rel = cookie->rels; rel < cookie->relend; rel++)
>+    if (rel->r_offset == offset)
>+      return rel;
>+  return NULL;
>+}
>+
>+/* Implementation of the SKIP_RELOCS macro for unordered relocations. */
>+static void
>+_bfd_skip_relocs_unordered (struct elf_reloc_cookie *cookie, bfd_vma offset,
>+			    bfd_vma *rels_offset)
>+{
>+  Elf_Internal_Rela *rel, *best = NULL;
>+  bfd_vma best_offs = -1;
>+
>+  /* FIXME: octets_per_byte.  */
>+  *rels_offset = offset;
>+  for (rel = cookie->rels; rel < cookie->relend; rel++)
>+    if (rel->r_offset >= offset && rel->r_offset - offset < best_offs)
>+      {
>+	best = rel;
>+	best_offs = rel->r_offset - offset;
>+      }
>+  cookie->rel = best ? best : cookie->relend;
>+}
>+
>+static struct reloc_read_ops _bfd_eh_unordered_relocs = {
>+  .chk_relocs = _bfd_chk_relocs_unordered,
>+  .get_reloc = _bfd_get_reloc_unordered,
>+  .skip_relocs = _bfd_skip_relocs_unordered,
>+};
>+
> /* Try to parse .eh_frame section SEC, which belongs to ABFD.  Store the
>    information in the section's sec_info field on success.  COOKIE
>    describes the relocations in SEC.  */
>@@ -473,6 +574,8 @@ _bfd_elf_parse_eh_frame (bfd *abfd, struct bfd_link_info *info,
> 
>   bfd_byte *ehbuf = NULL, *buf, *end;
>   bfd_byte *last_fde;
>+  bfd_size_type sec_info_size = 0;
>+  bfd_vma rels_offset = 0;
>   struct eh_cie_fde *this_inf;
>   unsigned int hdr_length, hdr_id;
>   unsigned int cie_count;
>@@ -484,6 +587,7 @@ _bfd_elf_parse_eh_frame (bfd *abfd, struct bfd_link_info *info,
>   unsigned int num_cies;
>   unsigned int num_entries;
>   elf_gc_mark_hook_fn gc_mark_hook;
>+  struct reloc_read_ops *rr_ops = NULL;
> 
>   htab = elf_hash_table (info);
>   hdr_info = &htab->eh_info;
>@@ -552,37 +656,32 @@ _bfd_elf_parse_eh_frame (bfd *abfd, struct bfd_link_info *info,
>       REQUIRE (skip_bytes (&buf, end, hdr_length - 4));
>     }
> 
>-  sec_info = (struct eh_frame_sec_info *)
>-      bfd_zmalloc (sizeof (struct eh_frame_sec_info)
>-                   + (num_entries - 1) * sizeof (struct eh_cie_fde));
>+  sec_info_size = sizeof (struct eh_frame_sec_info)
>+    + (num_entries - 1) * sizeof (struct eh_cie_fde);
>+  sec_info = (struct eh_frame_sec_info *) bfd_zmalloc (sec_info_size);
>   REQUIRE (sec_info);
> 
>   /* We need to have a "struct cie" for each CIE in this section.  */
>   local_cies = (struct cie *) bfd_zmalloc (num_cies * sizeof (*local_cies));
>   REQUIRE (local_cies);
> 
>-  /* FIXME: octets_per_byte.  */
>+  /* Start with the assumption that relocations are ordered by offset */
>+  rr_ops = &_bfd_eh_ordered_relocs;
>+
> #define ENSURE_NO_RELOCS(buf)				\
>-  REQUIRE (!(cookie->rel < cookie->relend		\
>-	     && (cookie->rel->r_offset			\
>-		 < (bfd_size_type) ((buf) - ehbuf))	\
>-	     && cookie->rel->r_info != 0))
>+  REQUIRE (!(rr_ops->chk_relocs (cookie, rels_offset,	\
>+	  (buf) - ehbuf)))
> 
>-  /* FIXME: octets_per_byte.  */
> #define SKIP_RELOCS(buf)				\
>-  while (cookie->rel < cookie->relend			\
>-	 && (cookie->rel->r_offset			\
>-	     < (bfd_size_type) ((buf) - ehbuf)))	\
>-    cookie->rel++
>+  (rr_ops->skip_relocs (cookie, (buf) - ehbuf,		\
>+			&rels_offset))
> 
>-  /* FIXME: octets_per_byte.  */
> #define GET_RELOC(buf)					\
>-  ((cookie->rel < cookie->relend			\
>-    && (cookie->rel->r_offset				\
>-	== (bfd_size_type) ((buf) - ehbuf)))		\
>-   ? cookie->rel : NULL)
>+  (rr_ops->get_reloc (cookie, (buf) - ehbuf))
> 
>+restart_reading:
>   buf = ehbuf;
>+  SKIP_RELOCS(buf);
>   cie_count = 0;
>   gc_mark_hook = get_elf_backend_data (abfd)->gc_mark_hook;
>   while ((bfd_size_type) (buf - ehbuf) != sec->size)
>@@ -718,11 +817,9 @@ _bfd_elf_parse_eh_frame (bfd *abfd, struct bfd_link_info *info,
> 		      REQUIRE (GET_RELOC (buf));
> 		      cie->personality.reloc_index
> 			= cookie->rel - cookie->rels;
>-		      /* Cope with MIPS-style composite relocations.  */
>-		      do
>-			cookie->rel++;
>-		      while (GET_RELOC (buf) != NULL);
> 		      REQUIRE (skip_bytes (&buf, end, per_width));
>+		      /* Cope with MIPS-style composite relocations.  */
>+		      SKIP_RELOCS(buf);
> 		    }
> 		    break;
> 		  default:
>@@ -913,6 +1010,14 @@ _bfd_elf_parse_eh_frame (bfd *abfd, struct bfd_link_info *info,
>   goto success;
> 
>  free_no_table:
>+  if (rr_ops == &_bfd_eh_ordered_relocs)
>+    {
>+      /* Perhaps, relocations are out of order. Retry with slower version
>+         that does not require ordering. */
>+      rr_ops = &_bfd_eh_unordered_relocs;
>+      memset(sec_info, 0, sec_info_size);
>+      goto restart_reading;
>+    }
>   (*info->callbacks->einfo)
>     (_("%P: error in %B(%A); no .eh_frame_hdr table will be created.\n"),
>      abfd, sec);
>-- 
>1.8.4.1
>

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Attachments on bug 16345: 7330