1 /*
2 * Copyright (c) 2011, 2016, 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.meta.Constant;
28 import jdk.vm.ci.meta.JavaConstant;
29 import jdk.vm.ci.meta.JavaKind;
30 import jdk.vm.ci.meta.MemoryAccessProvider;
31 import jdk.vm.ci.meta.PrimitiveConstant;
32
33 /**
34 * HotSpot implementation of {@link MemoryAccessProvider}.
35 */
36 class HotSpotMemoryAccessProviderImpl implements HotSpotMemoryAccessProvider {
37
38 protected final HotSpotJVMCIRuntimeProvider runtime;
39
40 HotSpotMemoryAccessProviderImpl(HotSpotJVMCIRuntimeProvider runtime) {
41 this.runtime = runtime;
42 }
43
44 private static Object asObject(Constant base) {
45 if (base instanceof HotSpotObjectConstantImpl) {
46 return ((HotSpotObjectConstantImpl) base).object();
47 } else {
48 return null;
49 }
50 }
51
52 private boolean isValidObjectFieldDisplacement(Constant base, long displacement) {
53 if (base instanceof HotSpotMetaspaceConstant) {
54 MetaspaceWrapperObject metaspaceObject = HotSpotMetaspaceConstantImpl.getMetaspaceObject(base);
55 if (metaspaceObject instanceof HotSpotResolvedObjectTypeImpl) {
56 if (displacement == runtime.getConfig().classMirrorOffset) {
57 // Klass::_java_mirror is valid for all Klass* values
58 return true;
59 }
60 } else {
61 throw new IllegalArgumentException(String.valueOf(metaspaceObject));
62 }
63 }
64 return false;
65 }
66
67 private static long asRawPointer(Constant base) {
68 if (base instanceof HotSpotMetaspaceConstantImpl) {
69 MetaspaceWrapperObject meta = HotSpotMetaspaceConstantImpl.getMetaspaceObject(base);
70 return meta.getMetaspacePointer();
71 } else if (base instanceof PrimitiveConstant) {
72 PrimitiveConstant prim = (PrimitiveConstant) base;
73 if (prim.getJavaKind().isNumericInteger()) {
74 return prim.asLong();
75 }
76 }
77 throw new IllegalArgumentException(String.valueOf(base));
78 }
79
80 private static long readRawValue(Constant baseConstant, long displacement, int bits) {
81 Object base = asObject(baseConstant);
82 if (base != null) {
83 switch (bits) {
84 case Byte.SIZE:
85 return UNSAFE.getByte(base, displacement);
86 case Short.SIZE:
87 return UNSAFE.getShort(base, displacement);
88 case Integer.SIZE:
89 return UNSAFE.getInt(base, displacement);
90 case Long.SIZE:
91 return UNSAFE.getLong(base, displacement);
92 default:
93 throw new IllegalArgumentException(String.valueOf(bits));
94 }
95 } else {
96 long pointer = asRawPointer(baseConstant);
97 switch (bits) {
98 case Byte.SIZE:
99 return UNSAFE.getByte(pointer + displacement);
100 case Short.SIZE:
101 return UNSAFE.getShort(pointer + displacement);
102 case Integer.SIZE:
103 return UNSAFE.getInt(pointer + displacement);
104 case Long.SIZE:
105 return UNSAFE.getLong(pointer + displacement);
106 default:
107 throw new IllegalArgumentException(String.valueOf(bits));
108 }
109 }
110 }
111
112 private boolean verifyReadRawObject(Object expected, Constant base, long displacement) {
113 if (base instanceof HotSpotMetaspaceConstant) {
114 MetaspaceWrapperObject metaspaceObject = HotSpotMetaspaceConstantImpl.getMetaspaceObject(base);
115 if (metaspaceObject instanceof HotSpotResolvedObjectTypeImpl) {
116 if (displacement == runtime.getConfig().classMirrorOffset) {
117 assert expected == ((HotSpotResolvedObjectTypeImpl) metaspaceObject).mirror();
118 }
119 }
120 }
121 return true;
122 }
123
124 private Object readRawObject(Constant baseConstant, long initialDisplacement, boolean compressed) {
125 long displacement = initialDisplacement;
126
127 Object ret;
128 Object base = asObject(baseConstant);
129 if (base == null) {
130 assert !compressed;
131 displacement += asRawPointer(baseConstant);
132 ret = UNSAFE.getUncompressedObject(displacement);
133 assert verifyReadRawObject(ret, baseConstant, initialDisplacement);
134 } else {
135 assert runtime.getConfig().useCompressedOops == compressed;
136 ret = UNSAFE.getObject(base, displacement);
137 }
138 return ret;
139 }
140
141 /**
142 * Reads a value of this kind using a base address and a displacement. No bounds checking or
143 * type checking is performed. Returns {@code null} if the value is not available at this point.
144 *
145 * @param baseConstant the base address from which the value is read.
146 * @param displacement the displacement within the object in bytes
147 * @return the read value encapsulated in a {@link JavaConstant} object, or {@code null} if the
148 * value cannot be read.
149 * @throws IllegalArgumentException if {@code kind} is {@code null}, {@link JavaKind#Void}, not
150 * {@link JavaKind#Object} or not {@linkplain JavaKind#isPrimitive() primitive} kind
151 */
152 JavaConstant readUnsafeConstant(JavaKind kind, JavaConstant baseConstant, long displacement) {
153 if (kind == null) {
154 throw new IllegalArgumentException("null JavaKind");
155 }
156 if (kind == JavaKind.Object) {
157 Object o = readRawObject(baseConstant, displacement, runtime.getConfig().useCompressedOops);
158 return HotSpotObjectConstantImpl.forObject(o);
159 } else {
160 int bits = kind.getByteCount() * Byte.SIZE;
161 return readPrimitiveConstant(kind, baseConstant, displacement, bits);
162 }
163 }
164
165 @Override
166 public JavaConstant readPrimitiveConstant(JavaKind kind, Constant baseConstant, long initialDisplacement, int bits) {
167 try {
168 long rawValue = readRawValue(baseConstant, initialDisplacement, bits);
169 switch (kind) {
170 case Boolean:
171 return JavaConstant.forBoolean(rawValue != 0);
172 case Byte:
173 return JavaConstant.forByte((byte) rawValue);
174 case Char:
175 return JavaConstant.forChar((char) rawValue);
176 case Short:
177 return JavaConstant.forShort((short) rawValue);
178 case Int:
179 return JavaConstant.forInt((int) rawValue);
180 case Long:
181 return JavaConstant.forLong(rawValue);
182 case Float:
183 return JavaConstant.forFloat(Float.intBitsToFloat((int) rawValue));
184 case Double:
185 return JavaConstant.forDouble(Double.longBitsToDouble(rawValue));
186 default:
187 throw new IllegalArgumentException("Unsupported kind: " + kind);
188 }
189 } catch (NullPointerException e) {
190 return null;
191 }
192 }
193
194 @Override
195 public JavaConstant readObjectConstant(Constant base, long displacement) {
196 if (!isValidObjectFieldDisplacement(base, displacement)) {
197 return null;
198 }
199 return HotSpotObjectConstantImpl.forObject(readRawObject(base, displacement, false));
200 }
201
202 @Override
203 public JavaConstant readNarrowOopConstant(Constant base, long displacement) {
204 return HotSpotObjectConstantImpl.forObject(readRawObject(base, displacement, true), true);
205 }
206
207 private HotSpotResolvedObjectTypeImpl readKlass(Constant base, long displacement, boolean compressed) {
208 assert (base instanceof HotSpotMetaspaceConstantImpl) || (base instanceof HotSpotObjectConstantImpl) : base.getClass();
209 Object baseObject = (base instanceof HotSpotMetaspaceConstantImpl) ? ((HotSpotMetaspaceConstantImpl) base).asResolvedJavaType() : ((HotSpotObjectConstantImpl) base).object();
210 return runtime.getCompilerToVM().getResolvedJavaType(baseObject, displacement, compressed);
211 }
212
213 @Override
214 public Constant readKlassPointerConstant(Constant base, long displacement) {
215 HotSpotResolvedObjectTypeImpl klass = readKlass(base, displacement, false);
216 if (klass == null) {
217 return JavaConstant.NULL_POINTER;
218 }
219 return HotSpotMetaspaceConstantImpl.forMetaspaceObject(klass, false);
220 }
221
222 @Override
223 public Constant readNarrowKlassPointerConstant(Constant base, long displacement) {
224 HotSpotResolvedObjectTypeImpl klass = readKlass(base, displacement, true);
225 if (klass == null) {
226 return HotSpotCompressedNullConstant.COMPRESSED_NULL;
227 }
228 return HotSpotMetaspaceConstantImpl.forMetaspaceObject(klass, true);
229 }
230
231 @Override
232 public Constant readMethodPointerConstant(Constant base, long displacement) {
233 assert (base instanceof HotSpotObjectConstantImpl);
234 Object baseObject = ((HotSpotObjectConstantImpl) base).object();
235 HotSpotResolvedJavaMethodImpl method = runtime.getCompilerToVM().getResolvedJavaMethod(baseObject, displacement);
236 return HotSpotMetaspaceConstantImpl.forMetaspaceObject(method, false);
237 }
238 }