1 /*
2 * Copyright (c) 2008, 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. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26 package sun.dyn;
27
28 import java.dyn.*;
29 import sun.dyn.empty.Empty;
30
31 /**
32 * Construction and caching of often-used invokers.
33 * @author jrose
34 */
35 public class Invokers {
36 // exact type (sans leading taget MH) for the outgoing call
37 private final MethodType targetType;
38
39 // exact invoker for the outgoing call
40 private /*lazy*/ MethodHandle exactInvoker;
41
42 // erased (partially untyped but with primitives) invoker for the outgoing call
43 private /*lazy*/ MethodHandle erasedInvoker;
44 /*lazy*/ MethodHandle erasedInvokerWithDrops; // for InvokeGeneric
45
46 // generic (untyped) invoker for the outgoing call
47 private /*lazy*/ MethodHandle genericInvoker;
48
49 // generic (untyped) invoker for the outgoing call; accepts a single Object[]
50 private final /*lazy*/ MethodHandle[] varargsInvokers;
51
52 // invoker for an unbound callsite
53 private /*lazy*/ MethodHandle uninitializedCallSite;
54
55 /** Compute and cache information common to all collecting adapters
56 * that implement members of the erasure-family of the given erased type.
57 */
58 public Invokers(Access token, MethodType targetType) {
59 Access.check(token);
60 this.targetType = targetType;
61 this.varargsInvokers = new MethodHandle[targetType.parameterCount()+1];
62 }
63
64 public static MethodType invokerType(MethodType targetType) {
65 return targetType.insertParameterTypes(0, MethodHandle.class);
66 }
67
68 public MethodHandle exactInvoker() {
69 MethodHandle invoker = exactInvoker;
70 if (invoker != null) return invoker;
71 try {
72 invoker = MethodHandleImpl.IMPL_LOOKUP.findVirtual(MethodHandle.class, "invoke", targetType);
73 } catch (NoAccessException ex) {
74 throw new InternalError("JVM cannot find invoker for "+targetType);
75 }
76 assert(invokerType(targetType) == invoker.type());
77 exactInvoker = invoker;
78 return invoker;
79 }
80
81 public MethodHandle genericInvoker() {
82 MethodHandle invoker1 = exactInvoker();
83 MethodHandle invoker = genericInvoker;
84 if (invoker != null) return invoker;
85 MethodType genericType = targetType.generic();
86 invoker = MethodHandles.convertArguments(invoker1, invokerType(genericType));
87 genericInvoker = invoker;
88 return invoker;
89 }
90
91 public MethodHandle erasedInvoker() {
92 MethodHandle invoker1 = exactInvoker();
93 MethodHandle invoker = erasedInvoker;
94 if (invoker != null) return invoker;
95 MethodType erasedType = targetType.erase();
96 if (erasedType == targetType.generic())
97 invoker = genericInvoker();
98 else
99 invoker = MethodHandles.convertArguments(invoker1, invokerType(erasedType));
100 erasedInvoker = invoker;
101 return invoker;
102 }
103
104 public MethodHandle varargsInvoker(int objectArgCount) {
105 MethodHandle vaInvoker = varargsInvokers[objectArgCount];
106 if (vaInvoker != null) return vaInvoker;
107 MethodHandle gInvoker = genericInvoker();
108 MethodType vaType = MethodType.genericMethodType(objectArgCount, true);
109 vaInvoker = MethodHandles.spreadArguments(gInvoker, invokerType(vaType));
110 varargsInvokers[objectArgCount] = vaInvoker;
111 return vaInvoker;
112 }
113
114 private static MethodHandle THROW_UCS = null;
115
116 public MethodHandle uninitializedCallSite() {
117 MethodHandle invoker = uninitializedCallSite;
118 if (invoker != null) return invoker;
119 if (targetType.parameterCount() > 0) {
120 MethodType type0 = targetType.dropParameterTypes(0, targetType.parameterCount());
121 Invokers invokers0 = MethodTypeImpl.invokers(Access.TOKEN, type0);
122 invoker = MethodHandles.dropArguments(invokers0.uninitializedCallSite(),
123 0, targetType.parameterList());
124 assert(invoker.type().equals(targetType));
125 uninitializedCallSite = invoker;
126 return invoker;
127 }
128 if (THROW_UCS == null) {
129 try {
130 THROW_UCS = MethodHandleImpl.IMPL_LOOKUP
131 .findStatic(CallSite.class, "uninitializedCallSite",
132 MethodType.methodType(Empty.class));
133 } catch (NoAccessException ex) {
134 throw new RuntimeException(ex);
135 }
136 }
137 invoker = AdapterMethodHandle.makeRetypeRaw(Access.TOKEN, targetType, THROW_UCS);
138 assert(invoker.type().equals(targetType));
139 uninitializedCallSite = invoker;
140 return invoker;
141 }
142
143 public String toString() {
144 return "Invokers"+targetType;
145 }
146 }