1/*
2 * Copyright (c) 2008, 2015, 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#include "precompiled.hpp"
26#include "asm/macroAssembler.hpp"
27#include "assembler_arm.inline.hpp"
28#include "memory/metaspaceShared.hpp"
29
30// Generate the self-patching vtable method:
31//
32// This method will be called (as any other Klass virtual method) with
33// the Klass itself as the first argument.  Example:
34//
35//      oop obj;
36//      int size = obj->klass()->oop_size(this);
37//
38// for which the virtual method call is Klass::oop_size();
39//
40// The dummy method is called with the Klass object as the first
41// operand, and an object as the second argument.
42//
43
44//=====================================================================
45
46// All of the dummy methods in the vtable are essentially identical,
47// differing only by an ordinal constant, and they bear no relationship
48// to the original method which the caller intended. Also, there needs
49// to be 'vtbl_list_size' instances of the vtable in order to
50// differentiate between the 'vtable_list_size' original Klass objects.
51
52#define __ masm->
53
54void MetaspaceShared::generate_vtable_methods(void** vtbl_list,
55                                                   void** vtable,
56                                                   char** md_top,
57                                                   char* md_end,
58                                                   char** mc_top,
59                                                   char* mc_end) {
60  intptr_t vtable_bytes = (num_virtuals * vtbl_list_size) * sizeof(void*);
61  *(intptr_t *)(*md_top) = vtable_bytes;
62  *md_top += sizeof(intptr_t);
63  void** dummy_vtable = (void**)*md_top;
64  *vtable = dummy_vtable;
65  *md_top += vtable_bytes;
66
67  CodeBuffer cb((unsigned char*)*mc_top, mc_end - *mc_top);
68  MacroAssembler* masm = new MacroAssembler(&cb);
69
70  for (int i = 0; i < vtbl_list_size; ++i) {
71    Label common_code;
72    for (int j = 0; j < num_virtuals; ++j) {
73      dummy_vtable[num_virtuals * i + j] = (void*) __ pc();
74      __ mov(Rtemp, j);  // Rtemp contains an index of a virtual method in the table
75      __ b(common_code);
76    }
77
78    InlinedAddress vtable_address((address)&vtbl_list[i]);
79    __ bind(common_code);
80    const Register tmp2 = AARCH64_ONLY(Rtemp2) NOT_AARCH64(R4);
81    assert_different_registers(Rtemp, tmp2);
82#ifndef AARCH64
83    __ push(tmp2);
84#endif // !AARCH64
85    // Do not use ldr_global since the code must be portable across all ARM architectures
86    __ ldr_literal(tmp2, vtable_address);
87    __ ldr(tmp2, Address(tmp2));                              // get correct vtable address
88    __ ldr(Rtemp, Address::indexed_ptr(tmp2, Rtemp));         // get real method pointer
89    __ str(tmp2, Address(R0));                                // update vtable. R0 = "this"
90#ifndef AARCH64
91    __ pop(tmp2);
92#endif // !AARCH64
93    __ jump(Rtemp);
94    __ bind_literal(vtable_address);
95  }
96
97  __ flush();
98  *mc_top = (char*) __ pc();
99}
100