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 #ifndef KERNEL
27 #include "assembler_sparc.inline.hpp"
28 #include "memory/compactingPermGenGen.hpp"
29 #include "memory/generation.inline.hpp"
30 #include "memory/space.inline.hpp"
31 #endif
32
33
34
35 // Generate the self-patching vtable method:
36 //
37 // This method will be called (as any other Klass virtual method) with
38 // the Klass itself as the first argument. Example:
39 //
40 // oop obj;
41 // int size = obj->klass()->klass_part()->oop_size(this);
42 //
43 // for which the virtual method call is Klass::oop_size();
44 //
45 // The dummy method is called with the Klass object as the first
46 // operand, and an object as the second argument.
47 //
48
49 //=====================================================================
50
51 // All of the dummy methods in the vtable are essentially identical,
52 // differing only by an ordinal constant, and they bear no releationship
53 // to the original method which the caller intended. Also, there needs
54 // to be 'vtbl_list_size' instances of the vtable in order to
55 // differentiate between the 'vtable_list_size' original Klass objects.
56
57 #define __ masm->
58
59 void CompactingPermGenGen::generate_vtable_methods(void** vtbl_list,
60 void** vtable,
61 char** md_top,
62 char* md_end,
63 char** mc_top,
64 char* mc_end) {
65
66 intptr_t vtable_bytes = (num_virtuals * vtbl_list_size) * sizeof(void*);
67 *(intptr_t *)(*md_top) = vtable_bytes;
68 *md_top += sizeof(intptr_t);
69 void** dummy_vtable = (void**)*md_top;
70 *vtable = dummy_vtable;
71 *md_top += vtable_bytes;
72
73 guarantee(*md_top <= md_end, "Insufficient space for vtables.");
74
75 // Get ready to generate dummy methods.
76
77 CodeBuffer cb((unsigned char*)*mc_top, mc_end - *mc_top);
78 MacroAssembler* masm = new MacroAssembler(&cb);
79
80 Label common_code;
81 for (int i = 0; i < vtbl_list_size; ++i) {
82 for (int j = 0; j < num_virtuals; ++j) {
83 dummy_vtable[num_virtuals * i + j] = (void*)masm->pc();
84 __ save(SP, -256, SP);
85 __ brx(Assembler::always, false, Assembler::pt, common_code);
86
87 // Load L0 with a value indicating vtable/offset pair.
88 // -- bits[ 7..0] (8 bits) which virtual method in table?
89 // -- bits[12..8] (5 bits) which virtual method table?
90 // -- must fit in 13-bit instruction immediate field.
91 __ delayed()->set((i << 8) + j, L0);
92 }
93 }
94
95 __ bind(common_code);
96
97 // Expecting to be called with the "this" pointer in O0/I0 (where
98 // "this" is a Klass object). In addition, L0 was set (above) to
99 // identify the method and table.
100
101 // Look up the correct vtable pointer.
102
103 __ set((intptr_t)vtbl_list, L2); // L2 = address of new vtable list.
104 __ srl(L0, 8, L3); // Isolate L3 = vtable identifier.
105 __ sll(L3, LogBytesPerWord, L3);
106 __ ld_ptr(L2, L3, L3); // L3 = new (correct) vtable pointer.
107 __ st_ptr(L3, Address(I0, 0)); // Save correct vtable ptr in entry.
108
109 // Restore registers and jump to the correct method;
110
111 __ and3(L0, 255, L4); // Isolate L3 = method offset;.
112 __ sll(L4, LogBytesPerWord, L4);
113 __ ld_ptr(L3, L4, L4); // Get address of correct virtual method
114 __ jmpl(L4, 0, G0); // Jump to correct method.
115 __ delayed()->restore(); // Restore registers.
116
117 __ flush();
118 *mc_top = (char*)__ pc();
119
120 guarantee(*mc_top <= mc_end, "Insufficient space for method wrappers.");
121 }