1 /*
   2  * Copyright (c) 2016, Oracle and/or its affiliates. All rights reserved.
   3  * Copyright (c) 2016 SAP SE. All rights reserved.
   4  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   5  *
   6  * This code is free software; you can redistribute it and/or modify it
   7  * under the terms of the GNU General Public License version 2 only, as
   8  * published by the Free Software Foundation.
   9  *
  10  * This code is distributed in the hope that it will be useful, but WITHOUT
  11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  12  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  13  * version 2 for more details (a copy is included in the LICENSE file that
  14  * accompanied this code).
  15  *
  16  * You should have received a copy of the GNU General Public License version
  17  * 2 along with this work; if not, write to the Free Software Foundation,
  18  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  19  *
  20  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  21  * or visit www.oracle.com if you need additional information or have any
  22  * questions.
  23  *
  24  */
  25 
  26 #include "precompiled.hpp"
  27 #include "asm/codeBuffer.hpp"
  28 #include "asm/macroAssembler.inline.hpp"
  29 #include "memory/metaspaceShared.hpp"
  30 
  31 // Generate the self-patching vtable method:
  32 //
  33 // This method will be called (as any other Klass virtual method) with
  34 // the Klass itself as the first argument. Example:
  35 //
  36 //   oop obj;
  37 //   int size = obj->klass()->klass_part()->oop_size(this);
  38 //
  39 // for which the virtual method call is Klass::oop_size();.
  40 //
  41 // The dummy method is called with the Klass object as the first
  42 // operand, and an object as the second argument.
  43 //
  44 
  45 //=====================================================================
  46 
  47 // All of the dummy methods in the vtable are essentially identical,
  48 // differing only by an ordinal constant, and they bear no releationship
  49 // to the original method which the caller intended. Also, there needs
  50 // to be 'vtbl_list_size' instances of the vtable in order to
  51 // differentiate between the 'vtable_list_size' original Klass objects.
  52 
  53 #undef __
  54 #define __ masm->
  55 
  56 void MetaspaceShared::generate_vtable_methods(void** vtbl_list,
  57                                               void** vtable,
  58                                               char** md_top,
  59                                               char* md_end,
  60                                               char** mc_top,
  61                                               char* mc_end) {
  62 
  63   intptr_t vtable_bytes = (num_virtuals * vtbl_list_size) * sizeof(void*);
  64   *(intptr_t *)(*md_top) = vtable_bytes;
  65   *md_top += sizeof(intptr_t);
  66   void** dummy_vtable = (void**)*md_top;
  67   *vtable = dummy_vtable;
  68   *md_top += vtable_bytes;
  69 
  70   // Get ready to generate dummy methods.
  71 
  72   CodeBuffer cb((unsigned char*)*mc_top, mc_end - *mc_top);
  73   MacroAssembler* masm = new MacroAssembler(&cb);
  74 
  75   __ unimplemented();
  76 }