Fix dwarf_getmacros so that it passes newly-added test
diff --git a/libdw/ChangeLog b/libdw/ChangeLog
index 93a5967..a3d9170 100644
--- a/libdw/ChangeLog
+++ b/libdw/ChangeLog
@@ -1,3 +1,8 @@
+2009-05-07  Petr Machata  <pmachata@redhat.com>
+
+	* dwarf_getmacros.c (dwarf_getmacros): Take into account offset in
+	DW_AT_macro_info attribute of CU DIE.
+
 2009-04-15  Roland McGrath  <roland@redhat.com>
 
 	* dwarf.h (DW_CIE_ID): Removed.
diff --git a/libdw/dwarf_getmacros.c b/libdw/dwarf_getmacros.c
index 743ade3..5f24d37 100644
--- a/libdw/dwarf_getmacros.c
+++ b/libdw/dwarf_getmacros.c
@@ -75,17 +75,20 @@
   if (INTUSE(dwarf_formudata) (&attr, &macoff) != 0)
     return -1;
 
-  const unsigned char *readp
-    = die->cu->dbg->sectiondata[IDX_debug_macinfo]->d_buf + offset;
-  const unsigned char *readendp
-    = readp + die->cu->dbg->sectiondata[IDX_debug_macinfo]->d_size;
+  Elf_Data *d = die->cu->dbg->sectiondata[IDX_debug_macinfo];
+  if (unlikely (d == NULL) || unlikely (d->d_buf == NULL))
+    {
+      __libdw_seterrno (DWARF_E_NO_ENTRY);
+      return -1;
+    }
+
+  const unsigned char *macdata = d->d_buf + macoff;
+  const unsigned char *readp =  macdata + offset;
+  const unsigned char *readendp = d->d_buf + d->d_size;
 
   if (readp == readendp)
     return 0;
 
-  if (*readp != DW_MACINFO_start_file)
-    goto invalid;
-
   while (readp < readendp)
     {
       unsigned int opcode = *readp++;
@@ -142,9 +145,7 @@
 	mac.param2.s = str;
 
       if (callback (&mac, arg) != DWARF_CB_OK)
-	return (readp
-		- ((unsigned char *) die->cu->dbg->sectiondata[IDX_debug_macinfo]->d_buf
-		   + offset));
+	return readp - macdata;
     }
 
   /* If we come here the termination of the data for the CU is not