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
54 void 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 }