1 /*
   2  * Copyright (c) 2019, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #ifndef SHARE_GC_SHARED_SCAVENGABLENMETHODS_HPP
  26 #define SHARE_GC_SHARED_SCAVENGABLENMETHODS_HPP
  27 
  28 #include "memory/allocation.hpp"
  29 #include "utilities/macros.hpp"
  30 
  31 class BoolObjectClosure;
  32 class CodeBlobClosure;
  33 class CodeBlobToOopClosure;
  34 class nmethod;
  35 
  36 class ScavengableNMethods : public AllStatic {
  37   friend class VMStructs;
  38 
  39   static nmethod*           _head;
  40   static BoolObjectClosure* _is_scavengable;
  41 
  42 public:
  43   static void initialize(BoolObjectClosure* is_scavengable);
  44 
  45   static void register_nmethod(nmethod* nm);
  46   static void unregister_nmethod(nmethod* nm);
  47   static void verify_nmethod(nmethod* nm);
  48   static void flush_nmethod(nmethod* nm);
  49 
  50   static void prune_nmethods();
  51 
  52   // Apply f to every live code blob in scavengable nmethods. Prune nmethods
  53   // from the list of scavengable nmethods if f->fix_relocations() and a nmethod
  54   // no longer has scavengable oops.  If f->fix_relocations(), then f must copy
  55   // objects to their new location immediately to avoid fixing nmethods on the
  56   // basis of the old object locations.
  57   static void scavengable_nmethods_do(CodeBlobToOopClosure* f);
  58 
  59   static void asserted_non_scavengable_nmethods_do(CodeBlobClosure* f = NULL) PRODUCT_RETURN;
  60 
  61 private:
  62   static void unlist_nmethod(nmethod* nm, nmethod* prev);
  63 
  64   static bool has_scavengable_oops(nmethod* nm);
  65 
  66   static void mark_on_list_nmethods() PRODUCT_RETURN;
  67   static void verify_unlisted_nmethods(CodeBlobClosure* f_or_null) PRODUCT_RETURN;
  68 };
  69 
  70 #endif // SHARE_GC_SHARED_SCAVENGABLENMETHODS_HPP