Re: [patch] Remove excessive DWARF block xmemdup by me

[Jan Kratochvil <jan dot kratochvil at redhat dot com>]

On Sun, 24 Jul 2011 19:51:23 +0200, Jan Kratochvil wrote:
> gdb/
> 2011-07-24  Jan Kratochvil  <jan.kratochvil@redhat.com>
> 
> 	Remove excessive DWARF expressions memory duplication.
> 	* dwarf2loc.c (per_cu_dwarf_call): Remove variable back_to and its use
> 	for block.data.
> 	(indirect_pieced_value): Remove variable result.  Remove variable
> 	back_to and its use for baton.data.
> 	(dwarf2_compile_expr_to_ax): Remove variable back_to and its use for
> 	block.data.
> 	* dwarf2read.c (dwarf2_fetch_die_location_block): Remove xmemdup.
> 	Update the function comment.

Checked in, with a small technical re-diff.
(This is just a fix-up of a fault of mine I checked in before.)


Sorry,
Jan


http://sourceware.org/ml/gdb-cvs/2011-09/msg00077.html

--- src/gdb/ChangeLog	2011/09/13 19:27:00	1.13327
+++ src/gdb/ChangeLog	2011/09/13 21:44:24	1.13328
@@ -1,3 +1,15 @@
+2011-09-13  Jan Kratochvil  <jan.kratochvil@redhat.com>
+
+	Remove excessive DWARF expressions memory duplication.
+	* dwarf2loc.c (per_cu_dwarf_call): Remove variable back_to and its use
+	for block.data.
+	(indirect_pieced_value): Remove variable result.  Remove variable
+	back_to and its use for baton.data.
+	(dwarf2_compile_expr_to_ax): Remove variable back_to and its use for
+	block.data.
+	* dwarf2read.c (dwarf2_fetch_die_location_block): Remove xmemdup.
+	Update the function comment.
+
 2011-09-13  Pedro Alves  <pedro@codesourcery.com>
 
 	* inferior.h (ALL_INFERIORS): New.
--- src/gdb/dwarf2loc.c	2011/08/08 21:41:13	1.127
+++ src/gdb/dwarf2loc.c	2011/09/13 21:44:27	1.128
@@ -265,19 +265,14 @@
 		   void *baton)
 {
   struct dwarf2_locexpr_baton block;
-  struct cleanup *back_to;
 
   block = dwarf2_fetch_die_location_block (die_offset, per_cu,
 					   get_frame_pc, baton);
 
-  back_to = make_cleanup (xfree, (void *) block.data);
-
   /* DW_OP_call_ref is currently not supported.  */
   gdb_assert (block.per_cu == per_cu);
 
   dwarf_expr_eval (ctx, block.data, block.size);
-
-  do_cleanups (back_to);
 }
 
 /* Helper interface of per_cu_dwarf_call for dwarf2_evaluate_loc_desc.  */
@@ -969,9 +964,7 @@
   struct dwarf2_locexpr_baton baton;
   int i, bit_offset, bit_length;
   struct dwarf_expr_piece *piece = NULL;
-  struct value *result;
   LONGEST byte_offset;
-  struct cleanup *back_to;
 
   type = check_typedef (value_type (value));
   if (TYPE_CODE (type) != TYPE_CODE_PTR)
@@ -1021,15 +1014,9 @@
 					   get_frame_address_in_block_wrapper,
 					   frame);
 
-  back_to = make_cleanup (xfree, (void *) baton.data);
-
-  result = dwarf2_evaluate_loc_desc_full (TYPE_TARGET_TYPE (type), frame,
-					  baton.data, baton.size, baton.per_cu,
-					  piece->v.ptr.offset + byte_offset);
-
-  do_cleanups (back_to);
-
-  return result;
+  return dwarf2_evaluate_loc_desc_full (TYPE_TARGET_TYPE (type), frame,
+					baton.data, baton.size, baton.per_cu,
+					piece->v.ptr.offset + byte_offset);
 }
 
 static void *
@@ -2147,14 +2134,12 @@
 	  {
 	    struct dwarf2_locexpr_baton block;
 	    int size = (op == DW_OP_call2 ? 2 : 4);
-	    struct cleanup *back_to;
 
 	    uoffset = extract_unsigned_integer (op_ptr, size, byte_order);
 	    op_ptr += size;
 
 	    block = dwarf2_fetch_die_location_block (uoffset, per_cu,
 						     get_ax_pc, expr);
-	    back_to = make_cleanup (xfree, (void *) block.data);
 
 	    /* DW_OP_call_ref is currently not supported.  */
 	    gdb_assert (block.per_cu == per_cu);
@@ -2162,8 +2147,6 @@
 	    dwarf2_compile_expr_to_ax (expr, loc, arch, addr_size,
 				       block.data, block.data + block.size,
 				       per_cu);
-
-	    do_cleanups (back_to);
 	  }
 	  break;
 
--- src/gdb/dwarf2read.c	2011/09/09 19:41:13	1.560
+++ src/gdb/dwarf2read.c	2011/09/13 21:44:27	1.561
@@ -13854,9 +13854,9 @@
   return die;
 }
 
-/* Return DWARF block and its CU referenced by OFFSET at PER_CU.  Returned
-   value is intended for DW_OP_call*.  You must call xfree on returned
-   dwarf2_locexpr_baton->data.  */
+/* Return DWARF block referenced by DW_AT_location of DIE at OFFSET at PER_CU.
+   Returned value is intended for DW_OP_call*.  Returned
+   dwarf2_locexpr_baton->data has lifetime of PER_CU->OBJFILE.  */
 
 struct dwarf2_locexpr_baton
 dwarf2_fetch_die_location_block (unsigned int offset,
@@ -13912,9 +13912,6 @@
     }
   retval.per_cu = cu->per_cu;
 
-  if (retval.data)
-    retval.data = xmemdup (retval.data, retval.size, retval.size);
-
   age_cached_comp_units ();
 
   return retval;