Wed, 08 Apr 2009 10:56:49 -0700
6655638: dynamic languages need method handles
Summary: initial implementation, with known omissions (x86/64, sparc, compiler optim., c-oops, C++ interp.)
Reviewed-by: kvn, twisti, never
1 /*
2 * Copyright 2004-2007 Sun Microsystems, Inc. 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
20 * CA 95054 USA or visit www.sun.com if you need additional information or
21 * have any questions.
22 *
23 */
25 # include "incls/_precompiled.incl"
26 # include "incls/_dump_sparc.cpp.incl"
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()->klass_part()->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 //
44 //=====================================================================
46 // All of the dummy methods in the vtable are essentially identical,
47 // differing only by an ordinal constant, and they bear no releationship
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.
52 #define __ masm->
54 void CompactingPermGenGen::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) {
61 intptr_t vtable_bytes = (num_virtuals * vtbl_list_size) * sizeof(void*);
62 *(intptr_t *)(*md_top) = vtable_bytes;
63 *md_top += sizeof(intptr_t);
64 void** dummy_vtable = (void**)*md_top;
65 *vtable = dummy_vtable;
66 *md_top += vtable_bytes;
68 guarantee(*md_top <= md_end, "Insufficient space for vtables.");
70 // Get ready to generate dummy methods.
72 CodeBuffer cb((unsigned char*)*mc_top, mc_end - *mc_top);
73 MacroAssembler* masm = new MacroAssembler(&cb);
75 Label common_code;
76 for (int i = 0; i < vtbl_list_size; ++i) {
77 for (int j = 0; j < num_virtuals; ++j) {
78 dummy_vtable[num_virtuals * i + j] = (void*)masm->pc();
79 __ save(SP, -256, SP);
80 __ brx(Assembler::always, false, Assembler::pt, common_code);
82 // Load L0 with a value indicating vtable/offset pair.
83 // -- bits[ 7..0] (8 bits) which virtual method in table?
84 // -- bits[12..8] (5 bits) which virtual method table?
85 // -- must fit in 13-bit instruction immediate field.
86 __ delayed()->set((i << 8) + j, L0);
87 }
88 }
90 __ bind(common_code);
92 // Expecting to be called with the "this" pointer in O0/I0 (where
93 // "this" is a Klass object). In addition, L0 was set (above) to
94 // identify the method and table.
96 // Look up the correct vtable pointer.
98 __ set((intptr_t)vtbl_list, L2); // L2 = address of new vtable list.
99 __ srl(L0, 8, L3); // Isolate L3 = vtable identifier.
100 __ sll(L3, LogBytesPerWord, L3);
101 __ ld_ptr(L2, L3, L3); // L3 = new (correct) vtable pointer.
102 __ st_ptr(L3, Address(I0, 0)); // Save correct vtable ptr in entry.
104 // Restore registers and jump to the correct method;
106 __ and3(L0, 255, L4); // Isolate L3 = method offset;.
107 __ sll(L4, LogBytesPerWord, L4);
108 __ ld_ptr(L3, L4, L4); // Get address of correct virtual method
109 Address method(L4, 0);
110 __ jmpl(method, G0); // Jump to correct method.
111 __ delayed()->restore(); // Restore registers.
113 __ flush();
114 *mc_top = (char*)__ pc();
116 guarantee(*mc_top <= mc_end, "Insufficient space for method wrappers.");
117 }