PR29925, Memory leak in find_abstract_instance

The testcase in the PR had a variable with both DW_AT_decl_file and
DW_AT_specification, where the DW_AT_specification also specified
DW_AT_decl_file.  This leads to a memory leak as the file name is
malloced and duplicates are not expected.

I've also changed find_abstract_instance to not use a temp for "name",
because that can result in a change in behaviour from the usual last
of duplicate attributes wins.

	PR 29925
	* dwarf2.c (find_abstract_instance): Delete "name" variable.
	Free *filename_ptr before assigning new file name.
	(scan_unit_for_symbols): Similarly free func->file and
	var->file before assigning.

diff --git a/bfd/dwarf2.c b/bfd/dwarf2.c
index 0cd8152ee6e4f84d6adb272333d8bbb58b84c6e0..b608afbc0cf260e98e2f87ab6d55c935937b2810 100644 (file)
--- a/bfd/dwarf2.c
+++ b/bfd/dwarf2.c
@@ -3441,7 +3441,6 @@ find_abstract_instance (struct comp_unit *unit,
   struct abbrev_info *abbrev;
   uint64_t die_ref = attr_ptr->u.val;
   struct attribute attr;
-  const char *name = NULL;
 
   if (recur_count == 100)
     {
@@ -3602,9 +3601,9 @@ find_abstract_instance (struct comp_unit *unit,
                case DW_AT_name:
                  /* Prefer DW_AT_MIPS_linkage_name or DW_AT_linkage_name
                     over DW_AT_name.  */
-                 if (name == NULL && is_str_form (&attr))
+                 if (*pname == NULL && is_str_form (&attr))
                    {
-                     name = attr.u.str;
+                     *pname = attr.u.str;
                      if (mangle_style (unit->lang) == 0)
                        *is_linkage = true;
                    }
@@ -3612,7 +3611,7 @@ find_abstract_instance (struct comp_unit *unit,
                case DW_AT_specification:
                  if (is_int_form (&attr)
                      && !find_abstract_instance (unit, &attr, recur_count + 1,
-                                                 &name, is_linkage,
+                                                 pname, is_linkage,
                                                  filename_ptr, linenumber_ptr))
                    return false;
                  break;
@@ -3622,7 +3621,7 @@ find_abstract_instance (struct comp_unit *unit,
                     non-string forms into these attributes.  */
                  if (is_str_form (&attr))
                    {
-                     name = attr.u.str;
+                     *pname = attr.u.str;
                      *is_linkage = true;
                    }
                  break;
@@ -3630,8 +3629,11 @@ find_abstract_instance (struct comp_unit *unit,
                  if (!comp_unit_maybe_decode_line_info (unit))
                    return false;
                  if (is_int_form (&attr))
-                   *filename_ptr = concat_filename (unit->line_table,
-                                                    attr.u.val);
+                   {
+                     free (*filename_ptr);
+                     *filename_ptr = concat_filename (unit->line_table,
+                                                      attr.u.val);
+                   }
                  break;
                case DW_AT_decl_line:
                  if (is_int_form (&attr))
@@ -3643,7 +3645,6 @@ find_abstract_instance (struct comp_unit *unit,
            }
        }
     }
-  *pname = name;
   return true;
 }
 
@@ -4139,8 +4140,11 @@ scan_unit_for_symbols (struct comp_unit *unit)
 
                case DW_AT_decl_file:
                  if (is_int_form (&attr))
-                   func->file = concat_filename (unit->line_table,
-                                                 attr.u.val);
+                   {
+                     free (func->file);
+                     func->file = concat_filename (unit->line_table,
+                                                   attr.u.val);
+                   }
                  break;
 
                case DW_AT_decl_line:
@@ -4182,8 +4186,11 @@ scan_unit_for_symbols (struct comp_unit *unit)
 
                case DW_AT_decl_file:
                  if (is_int_form (&attr))
-                   var->file = concat_filename (unit->line_table,
-                                                attr.u.val);
+                   {
+                     free (var->file);
+                     var->file = concat_filename (unit->line_table,
+                                                  attr.u.val);
+                   }
                  break;
 
                case DW_AT_decl_line: