Zero-initialize pass_manager

gcc/

	* passes.c (pass_manager::operator new): New.

From-SVN: r201506

gcc/ChangeLog

 2013-08-05  David Malcolm  <dmalcolm@redhat.com>
 
+	* passes.c (pass_manager::operator new): New.
+
+2013-08-05  David Malcolm  <dmalcolm@redhat.com>
+
 	Handwritten part of conversion of passes to C++ classes.
 
 	* Makefile.in (PASS_MANAGER_H): Add dep on pass-instances.def.

gcc/pass_manager.h

@@ -47,6 +47,8 @@ class context;
 class pass_manager
 {
 public:
+  void *operator new (size_t sz);
+
   pass_manager(context *ctxt);
 
   void register_pass (struct register_pass_info *pass_info);

gcc/passes.c

@@ -1339,6 +1339,13 @@ pass_manager::register_pass (struct register_pass_info *pass_info)
 				        -> all_passes
 */
 
+void *
+pass_manager::operator new (size_t sz)
+{
+  /* Ensure that all fields of the pass manager are zero-initialized.  */
+  return xcalloc (1, sz);
+}
+
 pass_manager::pass_manager (context *ctxt)
 : all_passes(NULL), all_small_ipa_passes(NULL), all_lowering_passes(NULL),
   all_regular_ipa_passes(NULL), all_lto_gen_passes(NULL),