[PATCH 3/3] libdw: save startp/endp boundaries in Dwarf_CU

[Josh Stone <jistone at redhat dot com>]

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         | 8 ++++++++
 libdw/dwarf_child.c     | 3 +--
 libdw/dwarf_cuoffset.c  | 4 ++--
 libdw/dwarf_dieoffset.c | 4 ++--
 libdw/dwarf_siblingof.c | 6 ++----
 libdw/libdwP.h          | 4 ++++
 libdw/libdw_findcu.c    | 6 +++++-
 7 files changed, 24 insertions(+), 11 deletions(-)

diff --git a/libdw/ChangeLog b/libdw/ChangeLog
index 2a69bea371fc..83a8c751f936 100644
--- a/libdw/ChangeLog
+++ b/libdw/ChangeLog
@@ -1,4 +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.
 
 2014-12-10  Josh Stone  <jistone@redhat.com>
diff --git a/libdw/dwarf_child.c b/libdw/dwarf_child.c
index 3e88fedf1df7..21185f4feda8 100644
--- a/libdw/dwarf_child.c
+++ b/libdw/dwarf_child.c
@@ -146,13 +146,12 @@ 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.  */
diff --git a/libdw/dwarf_cuoffset.c b/libdw/dwarf_cuoffset.c
index 7aea3f91f088..3ceffdb0b29a 100644
--- a/libdw/dwarf_cuoffset.c
+++ b/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));
 }
diff --git a/libdw/dwarf_dieoffset.c b/libdw/dwarf_dieoffset.c
index c92123ce5842..965b2c8dc76f 100644
--- a/libdw/dwarf_dieoffset.c
+++ b/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)
diff --git a/libdw/dwarf_siblingof.c b/libdw/dwarf_siblingof.c
index f2dc46888e91..27830ea450d4 100644
--- a/libdw/dwarf_siblingof.c
+++ b/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))
diff --git a/libdw/libdwP.h b/libdw/libdwP.h
index f391c94ed647..fa3dd7f27070 100644
--- a/libdw/libdwP.h
+++ b/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
diff --git a/libdw/libdw_findcu.c b/libdw/libdw_findcu.c
index c0bff2af2a69..3c9633e2b863 100644
--- a/libdw/libdw_findcu.c
+++ b/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)
     {
-- 
2.1.0