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
27 import jdk.vm.ci.code.TargetDescription;
28 import jdk.vm.ci.common.JVMCIError;
29 import jdk.vm.ci.hotspot.HotSpotVMConfig.CompressEncoding;
30 import jdk.vm.ci.meta.Constant;
31 import jdk.vm.ci.meta.JavaConstant;
32 import jdk.vm.ci.meta.JavaKind;
33 import jdk.vm.ci.meta.MemoryAccessProvider;
34 import jdk.vm.ci.meta.PrimitiveConstant;
35
36 /**
37 * HotSpot implementation of {@link MemoryAccessProvider}.
38 */
39 public class HotSpotMemoryAccessProviderImpl implements HotSpotMemoryAccessProvider, HotSpotProxified {
40
41 protected final HotSpotJVMCIRuntimeProvider runtime;
42
43 public HotSpotMemoryAccessProviderImpl(HotSpotJVMCIRuntimeProvider runtime) {
44 this.runtime = runtime;
45 }
46
47 private static Object asObject(Constant base) {
48 if (base instanceof HotSpotObjectConstantImpl) {
49 return ((HotSpotObjectConstantImpl) base).object();
50 } else {
51 return null;
52 }
53 }
54
55 private boolean isValidObjectFieldDisplacement(Constant base, long displacement) {
56 if (base instanceof HotSpotMetaspaceConstant) {
57 Object metaspaceObject = HotSpotMetaspaceConstantImpl.getMetaspaceObject(base);
58 if (metaspaceObject instanceof HotSpotResolvedObjectTypeImpl) {
59 if (displacement == runtime.getConfig().classMirrorOffset) {
60 // Klass::_java_mirror is valid for all Klass* values
61 return true;
62 }
63 } else {
64 throw new JVMCIError("%s", metaspaceObject);
65 }
66 }
67 return false;
68 }
69
70 private static long asRawPointer(Constant base) {
71 if (base instanceof HotSpotMetaspaceConstant) {
72 return ((HotSpotMetaspaceConstant) base).rawValue();
73 } else if (base instanceof PrimitiveConstant) {
74 PrimitiveConstant prim = (PrimitiveConstant) base;
75 if (prim.getJavaKind().isNumericInteger()) {
76 return prim.asLong();
77 }
78 }
79 throw new JVMCIError("%s", base);
80 }
81
82 private static long readRawValue(Constant baseConstant, long displacement, int bits) {
83 Object base = asObject(baseConstant);
84 if (base != null) {
85 switch (bits) {
86 case 8:
87 return UNSAFE.getByte(base, displacement);
88 case 16:
89 return UNSAFE.getShort(base, displacement);
90 case 32:
91 return UNSAFE.getInt(base, displacement);
92 case 64:
93 return UNSAFE.getLong(base, displacement);
94 default:
95 throw new JVMCIError("%d", bits);
96 }
97 } else {
98 long pointer = asRawPointer(baseConstant);
99 switch (bits) {
100 case 8:
101 return UNSAFE.getByte(pointer + displacement);
102 case 16:
103 return UNSAFE.getShort(pointer + displacement);
104 case 32:
105 return UNSAFE.getInt(pointer + displacement);
106 case 64:
107 return UNSAFE.getLong(pointer + displacement);
108 default:
109 throw new JVMCIError("%d", bits);
110 }
111 }
112 }
113
114 private boolean verifyReadRawObject(Object expected, Constant base, long displacement, boolean compressed) {
115 if (compressed == runtime.getConfig().useCompressedOops) {
116 Object obj = asObject(base);
117 if (obj != null) {
118 assert expected == UNSAFE.getObject(obj, displacement) : "readUnsafeOop doesn't agree with unsafe.getObject";
119 }
120 }
121 if (base instanceof HotSpotMetaspaceConstant) {
122 Object metaspaceObject = HotSpotMetaspaceConstantImpl.getMetaspaceObject(base);
123 if (metaspaceObject instanceof HotSpotResolvedObjectTypeImpl) {
124 if (displacement == runtime.getConfig().classMirrorOffset) {
125 assert expected == ((HotSpotResolvedObjectTypeImpl) metaspaceObject).mirror();
126 }
127 }
128 }
129 return true;
130 }
131
132 private Object readRawObject(Constant baseConstant, long initialDisplacement, boolean compressed) {
133 long displacement = initialDisplacement;
134
135 Object ret;
136 Object base = asObject(baseConstant);
137 if (base == null) {
138 assert !compressed;
139 displacement += asRawPointer(baseConstant);
140 ret = runtime.getCompilerToVM().readUncompressedOop(displacement);
141 } else {
142 assert runtime.getConfig().useCompressedOops == compressed;
143 ret = UNSAFE.getObject(base, displacement);
144 }
145 assert verifyReadRawObject(ret, baseConstant, initialDisplacement, compressed);
146 return ret;
147 }
148
149 @Override
150 public JavaConstant readUnsafeConstant(JavaKind kind, JavaConstant baseConstant, long displacement) {
151 if (kind == JavaKind.Object) {
152 Object o = readRawObject(baseConstant, displacement, runtime.getConfig().useCompressedOops);
153 return HotSpotObjectConstantImpl.forObject(o);
154 } else {
155 return readPrimitiveConstant(kind, baseConstant, displacement, kind.getByteCount() * 8);
156 }
157 }
158
159 @Override
160 public JavaConstant readPrimitiveConstant(JavaKind kind, Constant baseConstant, long initialDisplacement, int bits) {
161 try {
162 long rawValue = readRawValue(baseConstant, initialDisplacement, bits);
163 switch (kind) {
164 case Boolean:
165 return JavaConstant.forBoolean(rawValue != 0);
166 case Byte:
167 return JavaConstant.forByte((byte) rawValue);
168 case Char:
169 return JavaConstant.forChar((char) rawValue);
170 case Short:
171 return JavaConstant.forShort((short) rawValue);
172 case Int:
173 return JavaConstant.forInt((int) rawValue);
174 case Long:
175 return JavaConstant.forLong(rawValue);
176 case Float:
177 return JavaConstant.forFloat(Float.intBitsToFloat((int) rawValue));
178 case Double:
179 return JavaConstant.forDouble(Double.longBitsToDouble(rawValue));
180 default:
181 throw new JVMCIError("Unsupported kind: %s", kind);
182 }
183 } catch (NullPointerException e) {
184 return null;
185 }
186 }
187
188 @Override
189 public JavaConstant readObjectConstant(Constant base, long displacement) {
190 if (!isValidObjectFieldDisplacement(base, displacement)) {
191 return null;
192 }
193 return HotSpotObjectConstantImpl.forObject(readRawObject(base, displacement, false));
194 }
195
196 @Override
197 public JavaConstant readNarrowOopConstant(Constant base, long displacement, CompressEncoding encoding) {
198 assert encoding.equals(runtime.getConfig().getOopEncoding()) : "unexpected oop encoding: " + encoding + " != " + runtime.getConfig().getOopEncoding();
199 return HotSpotObjectConstantImpl.forObject(readRawObject(base, displacement, true), true);
200 }
201
202 private HotSpotResolvedObjectTypeImpl readKlass(Constant base, long displacement, boolean compressed) {
203 assert (base instanceof HotSpotMetaspaceConstantImpl) || (base instanceof HotSpotObjectConstantImpl) : base.getClass();
204 Object baseObject = (base instanceof HotSpotMetaspaceConstantImpl) ? ((HotSpotMetaspaceConstantImpl) base).asResolvedJavaType() : ((HotSpotObjectConstantImpl) base).object();
205 return runtime.getCompilerToVM().getResolvedJavaType(baseObject, displacement, compressed);
206 }
207
208 @Override
209 public Constant readKlassPointerConstant(Constant base, long displacement) {
210 HotSpotResolvedObjectTypeImpl klass = readKlass(base, displacement, false);
211 if (klass == null) {
212 return JavaConstant.NULL_POINTER;
213 }
214 TargetDescription target = runtime.getHostJVMCIBackend().getCodeCache().getTarget();
215 return HotSpotMetaspaceConstantImpl.forMetaspaceObject(target.wordKind, klass.getMetaspaceKlass(), klass, false);
216 }
217
218 @Override
219 public Constant readNarrowKlassPointerConstant(Constant base, long displacement, CompressEncoding encoding) {
220 HotSpotResolvedObjectTypeImpl klass = readKlass(base, displacement, true);
221 if (klass == null) {
222 return HotSpotCompressedNullConstant.COMPRESSED_NULL;
223 }
224 return HotSpotMetaspaceConstantImpl.forMetaspaceObject(JavaKind.Int, encoding.compress(klass.getMetaspaceKlass()), klass, true);
225 }
226
227 @Override
228 public Constant readMethodPointerConstant(Constant base, long displacement) {
229 TargetDescription target = runtime.getHostJVMCIBackend().getCodeCache().getTarget();
230 assert (base instanceof HotSpotObjectConstantImpl);
231 Object baseObject = ((HotSpotObjectConstantImpl) base).object();
232 HotSpotResolvedJavaMethodImpl method = runtime.getCompilerToVM().getResolvedJavaMethod(baseObject, displacement);
233 return HotSpotMetaspaceConstantImpl.forMetaspaceObject(target.wordKind, method.getMetaspaceMethod(), method, false);
234 }
235 }