libdw: save startp/endp boundaries in Dwarf_CU

Rather than looking up section data every time, we can simply save the
range of each CU as pointers in Dwarf_CU.

Signed-off-by: Josh Stone <jistone@redhat.com>

libdw/ChangeLog

@@ -1,3 +1,12 @@
+2014-12-10  Josh Stone  <jistone@redhat.com>
+
+	* libdwP.h (Dwarf_CU): Add startp and endp boundaries.
+	* libdw_findcu.c (__libdw_intern_next_unit): Set startp and endp.
+	* dwarf_child.c (dwarf_child): Use cu->endp.
+	* dwarf_cuoffset.c (dwarf_cuoffset): Use cu->startp.
+	* dwarf_dieoffset.c (dwarf_dieoffset): Use cu->startp.
+	* dwarf_siblingof.c (dwarf_siblingof): Use both.
+
 2014-12-10  Josh Stone  <jistone@redhat.com>
 
 	* dwarf_hasattr.c (dwarf_hasattr): Just walk abbrev for presence.

libdw/dwarf_child.c

@@ -147,13 +147,12 @@ dwarf_child (die, result)
 
   /* RESULT can be the same as DIE.  So preserve what we need.  */
   struct Dwarf_CU *cu = die->cu;
-  Elf_Data *cu_sec = cu_data (cu);
 
   /* It's kosher (just suboptimal) to have a null entry first thing (7.5.3).
      So if this starts with ULEB128 of 0 (even with silly encoding of 0),
      it is a kosher null entry and we do not really have any children.  */
   const unsigned char *code = addr;
-  const unsigned char *endp = (cu_sec->d_buf + cu_sec->d_size);
+  const unsigned char *endp = cu->endp;
   while (1)
     {
       if (unlikely (code >= endp)) /* Truncated section.  */

libdw/dwarf_cuoffset.c

@@ -1,5 +1,5 @@
 /* Return offset of DIE in CU.
-   Copyright (C) 2003-2010 Red Hat, Inc.
+   Copyright (C) 2003-2010, 2014 Red Hat, Inc.
    This file is part of elfutils.
    Written by Ulrich Drepper <drepper@redhat.com>, 2003.
 
@@ -41,5 +41,5 @@ dwarf_cuoffset (die)
 {
   return (die == NULL
 	  ? (Dwarf_Off) -1l
-	  : (die->addr - cu_data (die->cu)->d_buf - die->cu->start));
+	  : (Dwarf_Off) (die->addr - die->cu->startp));
 }

libdw/dwarf_dieoffset.c

@@ -1,5 +1,5 @@
 /* Return offset of DIE.
-   Copyright (C) 2003-2010 Red Hat, Inc.
+   Copyright (C) 2003-2010, 2014 Red Hat, Inc.
    This file is part of elfutils.
    Written by Ulrich Drepper <drepper@redhat.com>, 2003.
 
@@ -41,6 +41,6 @@ dwarf_dieoffset (die)
 {
   return (die == NULL
 	  ? ~0ul
-	  : (Dwarf_Off) (die->addr - cu_data (die->cu)->d_buf));
+	  : (Dwarf_Off) (die->addr - die->cu->startp + die->cu->start));
 }
 INTDEF(dwarf_dieoffset)

libdw/dwarf_siblingof.c

@@ -62,8 +62,7 @@ dwarf_siblingof (die, result)
   /* That's the address we start looking.  */
   unsigned char *addr = this_die.addr;
   /* End of the buffer.  */
-  unsigned char *endp
-    = ((unsigned char *) cu_data (sibattr.cu)->d_buf + sibattr.cu->end);
+  unsigned char *endp = sibattr.cu->endp;
 
   /* Search for the beginning of the next die on this level.  We
      must not return the dies for children of the given die.  */
@@ -81,8 +80,7 @@ dwarf_siblingof (die, result)
 	    return -1;
 
 	  /* Compute the next address.  */
-	  addr = ((unsigned char *) cu_data (sibattr.cu)->d_buf
-		  + sibattr.cu->start + offset);
+	  addr = sibattr.cu->startp + offset;
 	}
       else if (unlikely (addr == NULL)
 	       || unlikely (this_die.abbrev == DWARF_END_ABBREV))

libdw/libdwP.h

@@ -310,6 +310,10 @@ struct Dwarf_CU
 
   /* Known location lists.  */
   void *locs;
+
+  /* Memory boundaries of this CU.  */
+  void *startp;
+  void *endp;
 };
 
 /* Compute the offset of a CU's first DIE from its offset.  This

libdw/libdw_findcu.c

@@ -1,5 +1,5 @@
 /* Find CU for given offset.
-   Copyright (C) 2003-2010 Red Hat, Inc.
+   Copyright (C) 2003-2010, 2014 Red Hat, Inc.
    This file is part of elfutils.
    Written by Ulrich Drepper <drepper@redhat.com>, 2003.
 
@@ -113,6 +113,10 @@ __libdw_intern_next_unit (dbg, debug_types)
   if (debug_types)
     Dwarf_Sig8_Hash_insert (&dbg->sig8_hash, type_sig8, newp);
 
+  void *buf = cu_data (newp)->d_buf;
+  newp->startp = buf + newp->start;
+  newp->endp = buf + newp->end;
+
   /* Add the new entry to the search tree.  */
   if (tsearch (newp, tree, findcu_cb) == NULL)
     {