Squashed commit of the following:

commit 77abb31cb8d55980ef92260917a7ecdd228b1a44
Author: Petr Machata <pmachata@redhat.com>
Date:   Mon Jun 8 15:46:16 2009 +0200

    Fix a bug in offset checking

commit b794eac4f8d3e08101b5d2924523b1259bbc1b17
Author: Petr Machata <pmachata@redhat.com>
Date:   Wed Jun 3 16:00:01 2009 +0200

    Cosmetic, get rid of defining several variables per line

commit a23938fe35d515a3d75a51f6204771f3cf6c9ec4
Author: Petr Machata <pmachata@redhat.com>
Date:   Wed Jun 3 15:50:03 2009 +0200

    Restructure the code to decrease the binary size

commit 7c301e3d4e8584dfb3174855fb6af3d5791dfeed
Author: Petr Machata <pmachata@redhat.com>
Date:   Mon Jun 1 19:43:28 2009 +0200

    Shuffle a couple pieces of code around to make the code smaller

commit 6325323482c2a3e17409d32c7feec9461be26614
Merge: 83ac53d... e94b1b2...
Author: Petr Machata <pmachata@redhat.com>
Date:   Fri May 22 08:49:07 2009 +0200

    Merge branch 'master' of ssh://pmachata@git.fedorahosted.org/git/elfutils into pmachata/reader_hooks

    Conflicts:
    	libdw/ChangeLog

commit 83ac53db400945c074e77ec9904efe550903a0e2
Author: Petr Machata <pmachata@redhat.com>
Date:   Fri May 22 08:40:25 2009 +0200

    Call reloc hook with the original address, not incremented

commit f1996388745566abc1ca1c1700b3b7eded208575
Author: Petr Machata <pmachata@redhat.com>
Date:   Wed May 6 16:53:03 2009 +0200

    Rewrite boundary checking logic so that it's immune to arithmetic overflow

    * ... also get rid of some code redundancy.

commit 0c1df732822d83548edd0d005f3450281ed1701b
Author: Petr Machata <pmachata@redhat.com>
Date:   Wed May 6 16:25:09 2009 +0200

    __libdw_read_offset* take extra argument for header size checks

    * also presence of debug data and buffer is checked in __libdw_in_section

commit 6fb192e360f842cacb34a90c03cd0524cccc3dec
Author: Petr Machata <pmachata@redhat.com>
Date:   Wed May 6 15:51:20 2009 +0200

    Check for presence of data before loading the offset

commit a2e7612b165d83dd241225f87075fa4f58d18781
Author: Petr Machata <pmachata@redhat.com>
Date:   Wed May 6 15:04:16 2009 +0200

    Cosmetic changes

commit 8b1aad2c2f6c8dc02b3e704e4f386c1827e385cb
Author: Petr Machata <pmachata@redhat.com>
Date:   Tue May 5 15:34:13 2009 +0200

    Improve reader hook functions a bit

    * ... so that they are closer match to what's need on call sites

commit 3854b7fbab2fe331711365f94a295af82164d0d2
Author: Petr Machata <pmachata@redhat.com>
Date:   Tue May 5 14:33:50 2009 +0200

    Fixes in use of reader hooks in __libdw_formptr and dwarf_formudata

    * and a bit more

commit 335075596b6acef6e59919155e2b087e690a572d
Author: Petr Machata <pmachata@redhat.com>
Date:   Tue May 5 14:32:39 2009 +0200

    Rename __libdw_read_udata_addr to __libdw_formptr

commit 8273a2adaf8cb2ee203926af2849e4f96f8a6eaf
Author: Petr Machata <pmachata@redhat.com>
Date:   Tue May 5 02:53:40 2009 +0200

    Introduce __libdw_read_udata_address

    * the use in dwarf_ranges is iffy, there's a functionality mismatch.
      Need to find some better way

commit 1c897f4abde1530038d332f4fc03a596a24f6aaf
Author: Petr Machata <pmachata@redhat.com>
Date:   Mon May 4 18:09:13 2009 +0200

    ChangeLog entries for previous commit

commit 90d7c39454468b91c0fd6514a4e8d821222d6adb
Author: Petr Machata <pmachata@redhat.com>
Date:   Mon May 4 18:07:54 2009 +0200

    Fix bugs, introduce __libdw_read_begin_end_pair_inc

commit 9b3923f5b69a3e56590769435c4693f057acdc1f
Merge: 6200ba6... 589b3d3...
Author: Petr Machata <pmachata@redhat.com>
Date:   Mon May 4 12:22:21 2009 +0200

    Merge branch 'master' of ssh://pmachata@git.fedorahosted.org/git/elfutils into pmachata/reader_hooks

commit 6200ba62aa9ea3cb9318f73a27181907a528dbe4
Author: Petr Machata <pmachata@redhat.com>
Date:   Wed Apr 29 15:31:28 2009 +0200

    dwarf_getlocation_addr uses read hooks

commit ecbb8cdd8b500e37dc34fc246b912f704fe31ca4
Author: Petr Machata <pmachata@redhat.com>
Date:   Wed Apr 29 15:16:09 2009 +0200

    dwarf_ranges and dwarf_formref use read hooks

commit cb8f67b29a896c2660c10aa1028a9dbb377553e9
Author: Petr Machata <pmachata@redhat.com>
Date:   Tue Apr 28 18:39:04 2009 +0200

    Convert several new functions to use read hooks

commit b130453eb16a8cf042915e312cc5f189b8b92c01
Author: Petr Machata <pmachata@redhat.com>
Date:   Tue Apr 28 18:38:27 2009 +0200

    Add length read hooks

commit bd885ff694817b965231d99f1ab867947998e734
Author: Petr Machata <pmachata@redhat.com>
Date:   Tue Apr 28 18:36:17 2009 +0200

    Constify read hook arguments

commit 66fe03f1e489a88b89a15c9e13f9bd33db2729b1
Author: Petr Machata <pmachata@redhat.com>
Date:   Tue Apr 28 16:11:05 2009 +0200

    Change type of return value of offset read hooks to Dwarf_Off

commit 22b36e00cc228f5a966f84ca3323e5d652923ce8
Merge: 5b3534b... a7cb532...
Author: Petr Machata <pmachata@redhat.com>
Date:   Mon Apr 27 19:05:25 2009 +0200

    Merge branch 'master' of ssh://pmachata@git.fedorahosted.org/git/elfutils into pmachata/reader_hooks

commit 5b3534b62cbd45fe4f11dd1be3e492237938cce0
Author: Petr Machata <pmachata@redhat.com>
Date:   Mon Apr 27 18:53:06 2009 +0200

    Rewrites in read hooks

    * Have the checking and reading logic itself in the header so that it gets
      optimized out/inlined.  Call external relocating hook from there, there
      will presumably be more work to do, and we presumably don't want to keep
      this in the header.

commit 9e265d71d0eb900e76d6fdb0196ef4fc6507f3a7
Merge: 1783089... 300f3a4...
Author: Petr Machata <pmachata@redhat.com>
Date:   Thu Apr 23 17:45:25 2009 +0200

    Merge branch 'master' of ssh://pmachata@git.fedorahosted.org/git/elfutils into pmachata/reader_hooks

commit 1783089b184ddea2081bbe5ac4e80420cb6b0803
Author: Petr Machata <pmachata@redhat.com>
Date:   Thu Apr 23 17:44:48 2009 +0200

    Use the new reader hooks in several places

commit 11c3d97a5b40ea15edf324092b03da3050610d01
Author: Petr Machata <pmachata@redhat.com>
Date:   Thu Apr 23 17:40:03 2009 +0200

    Introduce reader hooks

1 files changed, 71 insertions, 34 deletions

diff --git a/libdw/dwarf_ranges.c b/libdw/dwarf_ranges.c
index 1eef617b..50fb6ba2 100644
--- a/libdw/dwarf_ranges.c
+++ b/libdw/dwarf_ranges.c
@@ -55,6 +55,52 @@
 #include <dwarf.h>
 #include <assert.h>
 
+/* Read up begin/end pair and increment read pointer.
+    - If it's normal range record, set up `*beginp' and `*endp' and return 0.
+    - If it's base address selection record, set up `*basep' and return 1.
+    - If it's end of rangelist, don't set anything and return 2
+    - If an error occurs, don't set anything and return -1.  */
+internal_function int
+__libdw_read_begin_end_pair_inc (Dwarf *dbg, int sec_index,
+				 unsigned char **addrp, int width,
+				 Dwarf_Addr *beginp, Dwarf_Addr *endp,
+				 Dwarf_Addr *basep)
+{
+  Dwarf_Addr escape = (width == 8 ? (Elf64_Addr) -1
+		       : (Elf64_Addr) (Elf32_Addr) -1);
+  Dwarf_Addr begin;
+  Dwarf_Addr end;
+
+  unsigned char *addr = *addrp;
+  bool begin_relocated = READ_AND_RELOCATE (__libdw_relocate_address, begin);
+  bool end_relocated = READ_AND_RELOCATE (__libdw_relocate_address, end);
+  *addrp = addr;
+
+  /* Unrelocated escape for begin means base address selection.  */
+  if (begin == escape && !begin_relocated)
+    {
+      if (unlikely (end == escape))
+	{
+	  __libdw_seterrno (DWARF_E_INVALID_DWARF);
+	  return -1;
+	}
+
+      if (basep != NULL)
+	*basep = end;
+      return 1;
+    }
+
+  /* Unrelocated pair of zeroes means end of range list.  */
+  if (begin == 0 && end == 0 && !begin_relocated && !end_relocated)
+    return 2;
+
+  /* Don't check for begin_relocated == end_relocated.  Serve the data
+     to the client even though it may be buggy.  */
+  *beginp = begin;
+  *endp = end;
+
+  return 0;
+}
 
 ptrdiff_t
 dwarf_ranges (Dwarf_Die *die, ptrdiff_t offset, Dwarf_Addr *basep,
@@ -80,11 +126,12 @@ dwarf_ranges (Dwarf_Die *die, ptrdiff_t offset, Dwarf_Addr *basep,
   const Elf_Data *d = die->cu->dbg->sectiondata[IDX_debug_ranges];
   if (d == NULL && offset != 0)
     {
-    no_ranges:
       __libdw_seterrno (DWARF_E_NO_DEBUG_RANGES);
       return -1;
     }
 
+  unsigned char *readp;
+  unsigned char *readendp;
   if (offset == 0)
     {
       Dwarf_Attribute attr_mem;
@@ -94,14 +141,12 @@ dwarf_ranges (Dwarf_Die *die, ptrdiff_t offset, Dwarf_Addr *basep,
 	/* No PC attributes in this DIE at all, so an empty range list.  */
 	return 0;
 
-      /* Must have the form data4 or data8 which act as an offset.  */
       Dwarf_Word start_offset;
-      if (INTUSE(dwarf_formudata) (attr, &start_offset) != 0)
+      if ((readp = __libdw_formptr (attr, IDX_debug_ranges,
+				    DWARF_E_NO_DEBUG_RANGES,
+				    &readendp, &start_offset)) == NULL)
 	return -1;
 
-      if (d == NULL)
-	goto no_ranges;
-
       offset = start_offset;
       assert ((Dwarf_Word) offset == start_offset);
 
@@ -127,45 +172,37 @@ dwarf_ranges (Dwarf_Die *die, ptrdiff_t offset, Dwarf_Addr *basep,
 	  return -1;
 	}
     }
-  else if (offset < 0 || (size_t) offset >= d->d_size)
+  else
     {
-      __libdw_seterrno (DWARF_E_INVALID_OFFSET);
-      return -1l;
-    }
+      if (__libdw_offset_in_section (die->cu->dbg,
+				     IDX_debug_ranges, offset, 1))
+	return -1l;
 
-  unsigned char *readp = d->d_buf + offset;
+      readp = d->d_buf + offset;
+      readendp = d->d_buf + d->d_size;
+    }
 
  next:
-  if ((unsigned char *) d->d_buf + d->d_size - readp
-      < die->cu->address_size * 2)
+  if (readendp - readp < die->cu->address_size * 2)
     goto invalid;
 
   Dwarf_Addr begin;
   Dwarf_Addr end;
-  if (die->cu->address_size == 8)
-    {
-      begin = read_8ubyte_unaligned_inc (die->cu->dbg, readp);
-      end = read_8ubyte_unaligned_inc (die->cu->dbg, readp);
-      if (begin == (uint64_t) -1l) /* Base address entry.  */
-	{
-	  *basep = end;
-	  goto next;
-	}
-    }
-  else
+
+  switch (__libdw_read_begin_end_pair_inc (die->cu->dbg, IDX_debug_ranges,
+					   &readp, die->cu->address_size,
+					   &begin, &end, basep))
     {
-      begin = read_4ubyte_unaligned_inc (die->cu->dbg, readp);
-      end = read_4ubyte_unaligned_inc (die->cu->dbg, readp);
-      if (begin == (uint32_t) -1) /* Base address entry.  */
-	{
-	  *basep = end;
-	  goto next;
-	}
+    case 0:
+      break;
+    case 1:
+      goto next;
+    case 2:
+      return 0;
+    default:
+      return -1l;
     }
 
-  if (begin == 0 && end == 0) /* End of list entry.  */
-    return 0;
-
   /* We have an address range entry.  */
   *startp = *basep + begin;
   *endp = *basep + end;