1 /*
2 * Copyright (c) 2011, 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 package jdk.vm.ci.hotspot;
24
25 import static jdk.vm.ci.hotspot.UnsafeAccess.UNSAFE;
26 import jdk.vm.ci.common.JVMCIError;
27 import jdk.vm.ci.hotspot.HotSpotVMConfig.CompressEncoding;
28 import jdk.vm.ci.meta.Constant;
29 import jdk.vm.ci.meta.JavaConstant;
30 import jdk.vm.ci.meta.JavaKind;
31 import jdk.vm.ci.meta.MemoryAccessProvider;
32 import jdk.vm.ci.meta.PrimitiveConstant;
33
34 /**
35 * HotSpot implementation of {@link MemoryAccessProvider}.
36 */
37 class HotSpotMemoryAccessProviderImpl implements HotSpotMemoryAccessProvider, HotSpotProxified {
38
39 protected final HotSpotJVMCIRuntimeProvider runtime;
40
41 public HotSpotMemoryAccessProviderImpl(HotSpotJVMCIRuntimeProvider runtime) {
42 this.runtime = runtime;
43 }
44
45 private static Object asObject(Constant base) {
46 if (base instanceof HotSpotObjectConstantImpl) {
47 return ((HotSpotObjectConstantImpl) base).object();
48 } else {
49 return null;
50 }
51 }
52
53 private boolean isValidObjectFieldDisplacement(Constant base, long displacement) {
54 if (base instanceof HotSpotMetaspaceConstant) {
55 MetaspaceWrapperObject metaspaceObject = HotSpotMetaspaceConstantImpl.getMetaspaceObject(base);
56 if (metaspaceObject instanceof HotSpotResolvedObjectTypeImpl) {
57 if (displacement == runtime.getConfig().classMirrorOffset) {
58 // Klass::_java_mirror is valid for all Klass* values
59 return true;
60 }
61 } else {
62 throw new JVMCIError("%s", metaspaceObject);
63 }
64 }
65 return false;
66 }
67
68 private static long asRawPointer(Constant base) {
69 if (base instanceof HotSpotMetaspaceConstantImpl) {
70 MetaspaceWrapperObject meta = HotSpotMetaspaceConstantImpl.getMetaspaceObject(base);
71 return meta.getMetaspacePointer();
72 } else if (base instanceof PrimitiveConstant) {
73 PrimitiveConstant prim = (PrimitiveConstant) base;
74 if (prim.getJavaKind().isNumericInteger()) {
75 return prim.asLong();
76 }
77 }
78 throw new JVMCIError("%s", base);
79 }
80
81 private static long readRawValue(Constant baseConstant, long displacement, int bits) {
82 Object base = asObject(baseConstant);
83 if (base != null) {
84 switch (bits) {
85 case 8:
86 return UNSAFE.getByte(base, displacement);
87 case 16:
88 return UNSAFE.getShort(base, displacement);
89 case 32:
90 return UNSAFE.getInt(base, displacement);
91 case 64:
92 return UNSAFE.getLong(base, displacement);
93 default:
94 throw new JVMCIError("%d", bits);
95 }
96 } else {
97 long pointer = asRawPointer(baseConstant);
98 switch (bits) {
99 case 8:
100 return UNSAFE.getByte(pointer + displacement);
101 case 16:
102 return UNSAFE.getShort(pointer + displacement);
103 case 32:
104 return UNSAFE.getInt(pointer + displacement);
105 case 64:
106 return UNSAFE.getLong(pointer + displacement);
107 default:
108 throw new JVMCIError("%d", bits);
109 }
110 }
111 }
112
113 private boolean verifyReadRawObject(Object expected, Constant base, long displacement, boolean compressed) {
114 if (compressed == runtime.getConfig().useCompressedOops) {
115 Object obj = asObject(base);
116 if (obj != null) {
117 assert expected == UNSAFE.getObject(obj, displacement) : "readUnsafeOop doesn't agree with unsafe.getObject";
118 }
119 }
120 if (base instanceof HotSpotMetaspaceConstant) {
121 MetaspaceWrapperObject metaspaceObject = HotSpotMetaspaceConstantImpl.getMetaspaceObject(base);
122 if (metaspaceObject instanceof HotSpotResolvedObjectTypeImpl) {
123 if (displacement == runtime.getConfig().classMirrorOffset) {
124 assert expected == ((HotSpotResolvedObjectTypeImpl) metaspaceObject).mirror();
125 }
126 }
127 }
128 return true;
129 }
130
131 private Object readRawObject(Constant baseConstant, long initialDisplacement, boolean compressed) {
132 long displacement = initialDisplacement;
133
134 Object ret;
135 Object base = asObject(baseConstant);
136 if (base == null) {
137 assert !compressed;
138 displacement += asRawPointer(baseConstant);
139 ret = runtime.getCompilerToVM().readUncompressedOop(displacement);
140 } else {
141 assert runtime.getConfig().useCompressedOops == compressed;
142 ret = UNSAFE.getObject(base, displacement);
143 }
144 assert verifyReadRawObject(ret, baseConstant, initialDisplacement, compressed);
145 return ret;
146 }
147
148 @Override
149 public JavaConstant readUnsafeConstant(JavaKind kind, JavaConstant baseConstant, long displacement) {
150 if (kind == JavaKind.Object) {
151 Object o = readRawObject(baseConstant, displacement, runtime.getConfig().useCompressedOops);
152 return HotSpotObjectConstantImpl.forObject(o);
153 } else {
154 return readPrimitiveConstant(kind, baseConstant, displacement, kind.getByteCount() * 8);
155 }
156 }
157
158 @Override
159 public JavaConstant readPrimitiveConstant(JavaKind kind, Constant baseConstant, long initialDisplacement, int bits) {
160 try {
161 long rawValue = readRawValue(baseConstant, initialDisplacement, bits);
162 switch (kind) {
163 case Boolean:
164 return JavaConstant.forBoolean(rawValue != 0);
165 case Byte:
166 return JavaConstant.forByte((byte) rawValue);
167 case Char:
168 return JavaConstant.forChar((char) rawValue);
169 case Short:
170 return JavaConstant.forShort((short) rawValue);
171 case Int:
172 return JavaConstant.forInt((int) rawValue);
173 case Long:
174 return JavaConstant.forLong(rawValue);
175 case Float:
176 return JavaConstant.forFloat(Float.intBitsToFloat((int) rawValue));
177 case Double:
178 return JavaConstant.forDouble(Double.longBitsToDouble(rawValue));
179 default:
180 throw new JVMCIError("Unsupported kind: %s", kind);
181 }
182 } catch (NullPointerException e) {
183 return null;
184 }
185 }
186
187 @Override
188 public JavaConstant readObjectConstant(Constant base, long displacement) {
189 if (!isValidObjectFieldDisplacement(base, displacement)) {
190 return null;
191 }
192 return HotSpotObjectConstantImpl.forObject(readRawObject(base, displacement, false));
193 }
194
195 @Override
196 public JavaConstant readNarrowOopConstant(Constant base, long displacement, CompressEncoding encoding) {
197 assert encoding.equals(runtime.getConfig().getOopEncoding()) : "unexpected oop encoding: " + encoding + " != " + runtime.getConfig().getOopEncoding();
198 return HotSpotObjectConstantImpl.forObject(readRawObject(base, displacement, true), true);
199 }
200
201 private HotSpotResolvedObjectTypeImpl readKlass(Constant base, long displacement, boolean compressed) {
202 assert (base instanceof HotSpotMetaspaceConstantImpl) || (base instanceof HotSpotObjectConstantImpl) : base.getClass();
203 Object baseObject = (base instanceof HotSpotMetaspaceConstantImpl) ? ((HotSpotMetaspaceConstantImpl) base).asResolvedJavaType() : ((HotSpotObjectConstantImpl) base).object();
204 return runtime.getCompilerToVM().getResolvedJavaType(baseObject, displacement, compressed);
205 }
206
207 @Override
208 public Constant readKlassPointerConstant(Constant base, long displacement) {
209 HotSpotResolvedObjectTypeImpl klass = readKlass(base, displacement, false);
210 if (klass == null) {
211 return JavaConstant.NULL_POINTER;
212 }
213 return HotSpotMetaspaceConstantImpl.forMetaspaceObject(klass, false);
214 }
215
216 @Override
217 public Constant readNarrowKlassPointerConstant(Constant base, long displacement, CompressEncoding encoding) {
218 HotSpotResolvedObjectTypeImpl klass = readKlass(base, displacement, true);
219 if (klass == null) {
220 return HotSpotCompressedNullConstant.COMPRESSED_NULL;
221 }
222 return HotSpotMetaspaceConstantImpl.forMetaspaceObject(klass, true);
223 }
224
225 @Override
226 public Constant readMethodPointerConstant(Constant base, long displacement) {
227 assert (base instanceof HotSpotObjectConstantImpl);
228 Object baseObject = ((HotSpotObjectConstantImpl) base).object();
229 HotSpotResolvedJavaMethodImpl method = runtime.getCompilerToVM().getResolvedJavaMethod(baseObject, displacement);
230 return HotSpotMetaspaceConstantImpl.forMetaspaceObject(method, false);
231 }
232 }