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, 7 insertions, 8 deletions

diff --git a/libdw/dwarf_nextcu.c b/libdw/dwarf_nextcu.c
index 9e5a96bc..66cde78a 100644
--- a/libdw/dwarf_nextcu.c
+++ b/libdw/dwarf_nextcu.c
@@ -84,7 +84,8 @@ dwarf_nextcu (dwarf, off, next_off, header_sizep, abbrev_offsetp,
 
   /* This points into the .debug_info section to the beginning of the
      CU entry.  */
-  char *bytes = (char *) dwarf->sectiondata[IDX_debug_info]->d_buf + off;
+  unsigned char *data = dwarf->sectiondata[IDX_debug_info]->d_buf;
+  unsigned char *bytes = data + off;
 
   /* The format of the CU header is described in dwarf2p1 7.5.1:
 
@@ -144,10 +145,10 @@ dwarf_nextcu (dwarf, off, next_off, header_sizep, abbrev_offsetp,
   /* Get offset in .debug_abbrev.  Note that the size of the entry
      depends on whether this is a 32-bit or 64-bit DWARF definition.  */
   uint64_t abbrev_offset;
-  if (offset_size == 4)
-    abbrev_offset = read_4ubyte_unaligned_inc (dwarf, bytes);
-  else
-    abbrev_offset = read_8ubyte_unaligned_inc (dwarf, bytes);
+  if (__libdw_read_offset_inc (dwarf, IDX_debug_info, &bytes, offset_size,
+			       &abbrev_offset, IDX_debug_abbrev, 0))
+    return -1;
+
   if (abbrev_offsetp != NULL)
     *abbrev_offsetp = abbrev_offset;
 
@@ -162,9 +163,7 @@ dwarf_nextcu (dwarf, off, next_off, header_sizep, abbrev_offsetp,
 
   /* Store the header length.  */
   if (header_sizep != NULL)
-    *header_sizep = (bytes
-		     - ((char *) dwarf->sectiondata[IDX_debug_info]->d_buf
-			+ off));
+    *header_sizep = bytes - (data + off);
 
   /* See definition of DIE_OFFSET_FROM_CU_OFFSET macro
      for an explanation of the trick in this expression.  */