[PATCH] Avoid an allocation in attr_to_dynamic_prop

[Tom Tromey <tom@tromey.com>]

I noticed that attr_to_dynamic_prop allocates a dwarf_block, when no
allocation is required.  This patch stack-allocates the object
instead.
---
 gdb/dwarf2/read.c | 17 ++++++++---------
 1 file changed, 8 insertions(+), 9 deletions(-)

diff --git a/gdb/dwarf2/read.c b/gdb/dwarf2/read.c
index e873d9cc440..34bbb6e804d 100644
--- a/gdb/dwarf2/read.c
+++ b/gdb/dwarf2/read.c
@@ -15385,24 +15385,23 @@ attr_to_dynamic_prop (const struct attribute *attr, struct die_info *die,
       baton->locexpr.per_cu = cu->per_cu;
       baton->locexpr.per_objfile = per_objfile;
 
-      struct dwarf_block *block;
+      struct dwarf_block block;
       if (attr->form == DW_FORM_data16)
 	{
 	  size_t data_size = 16;
-	  block = XOBNEW (obstack, struct dwarf_block);
-	  block->size = (data_size
-			 + 2 /* Extra bytes for DW_OP and arg.  */);
-	  gdb_byte *data = XOBNEWVEC (obstack, gdb_byte, block->size);
+	  block.size = (data_size
+			+ 2 /* Extra bytes for DW_OP and arg.  */);
+	  gdb_byte *data = XOBNEWVEC (obstack, gdb_byte, block.size);
 	  data[0] = DW_OP_implicit_value;
 	  data[1] = data_size;
 	  memcpy (&data[2], attr->as_block ()->data, data_size);
-	  block->data = data;
+	  block.data = data;
 	}
       else
-	block = attr->as_block ();
+	block = *attr->as_block ();
 
-      baton->locexpr.size = block->size;
-      baton->locexpr.data = block->data;
+      baton->locexpr.size = block.size;
+      baton->locexpr.data = block.data;
       switch (attr->name)
 	{
 	case DW_AT_string_length:
-- 
2.43.0