1 /*
2 * Copyright (c) 2004, 2010, 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 "assembler_sparc.inline.hpp"
27 #include "memory/compactingPermGenGen.hpp"
28 #include "memory/generation.inline.hpp"
29 #include "memory/space.inline.hpp"
30
31
32
33 // Generate the self-patching vtable method:
34 //
35 // This method will be called (as any other Klass virtual method) with
36 // the Klass itself as the first argument. Example:
37 //
38 // oop obj;
39 // int size = obj->klass()->klass_part()->oop_size(this);
40 //
41 // for which the virtual method call is Klass::oop_size();
42 //
43 // The dummy method is called with the Klass object as the first
44 // operand, and an object as the second argument.
45 //
46
47 //=====================================================================
48
49 // All of the dummy methods in the vtable are essentially identical,
50 // differing only by an ordinal constant, and they bear no releationship
51 // to the original method which the caller intended. Also, there needs
52 // to be 'vtbl_list_size' instances of the vtable in order to
53 // differentiate between the 'vtable_list_size' original Klass objects.
54
55 #define __ masm->
56
57 void CompactingPermGenGen::generate_vtable_methods(void** vtbl_list,
58 void** vtable,
59 char** md_top,
60 char* md_end,
61 char** mc_top,
62 char* mc_end) {
63
64 intptr_t vtable_bytes = (num_virtuals * vtbl_list_size) * sizeof(void*);
65 *(intptr_t *)(*md_top) = vtable_bytes;
66 *md_top += sizeof(intptr_t);
67 void** dummy_vtable = (void**)*md_top;
68 *vtable = dummy_vtable;
69 *md_top += vtable_bytes;
70
71 guarantee(*md_top <= md_end, "Insufficient space for vtables.");
72
73 // Get ready to generate dummy methods.
74
75 CodeBuffer cb((unsigned char*)*mc_top, mc_end - *mc_top);
76 MacroAssembler* masm = new MacroAssembler(&cb);
77
78 Label common_code;
79 for (int i = 0; i < vtbl_list_size; ++i) {
80 for (int j = 0; j < num_virtuals; ++j) {
81 dummy_vtable[num_virtuals * i + j] = (void*)masm->pc();
82 __ save(SP, -256, SP);
83 __ brx(Assembler::always, false, Assembler::pt, common_code);
84
85 // Load L0 with a value indicating vtable/offset pair.
86 // -- bits[ 7..0] (8 bits) which virtual method in table?
87 // -- bits[12..8] (5 bits) which virtual method table?
88 // -- must fit in 13-bit instruction immediate field.
89 __ delayed()->set((i << 8) + j, L0);
90 }
91 }
92
93 __ bind(common_code);
94
95 // Expecting to be called with the "this" pointer in O0/I0 (where
96 // "this" is a Klass object). In addition, L0 was set (above) to
97 // identify the method and table.
98
99 // Look up the correct vtable pointer.
100
101 __ set((intptr_t)vtbl_list, L2); // L2 = address of new vtable list.
102 __ srl(L0, 8, L3); // Isolate L3 = vtable identifier.
103 __ sll(L3, LogBytesPerWord, L3);
104 __ ld_ptr(L2, L3, L3); // L3 = new (correct) vtable pointer.
105 __ st_ptr(L3, Address(I0, 0)); // Save correct vtable ptr in entry.
106
107 // Restore registers and jump to the correct method;
108
109 __ and3(L0, 255, L4); // Isolate L3 = method offset;.
110 __ sll(L4, LogBytesPerWord, L4);
111 __ ld_ptr(L3, L4, L4); // Get address of correct virtual method
112 __ jmpl(L4, 0, G0); // Jump to correct method.
113 __ delayed()->restore(); // Restore registers.
114
115 __ flush();
116 *mc_top = (char*)__ pc();
117
118 guarantee(*mc_top <= mc_end, "Insufficient space for method wrappers.");
119 }