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 import jdk.vm.ci.hotspot.HotSpotVMConfig.CompressEncoding;
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, HotSpotProxified {
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, boolean compressed) {
113 if (compressed == runtime.getConfig().useCompressedOops) {
114 Object obj = asObject(base);
115 if (obj != null) {
116 assert expected == UNSAFE.getObject(obj, displacement) : "readUnsafeOop doesn't agree with unsafe.getObject";
117 }
118 }
119 if (base instanceof HotSpotMetaspaceConstant) {
120 MetaspaceWrapperObject metaspaceObject = HotSpotMetaspaceConstantImpl.getMetaspaceObject(base);
121 if (metaspaceObject instanceof HotSpotResolvedObjectTypeImpl) {
122 if (displacement == runtime.getConfig().classMirrorOffset) {
123 assert expected == ((HotSpotResolvedObjectTypeImpl) metaspaceObject).mirror();
124 }
125 }
126 }
127 return true;
128 }
129
130 private Object readRawObject(Constant baseConstant, long initialDisplacement, boolean compressed) {
131 long displacement = initialDisplacement;
132
133 Object ret;
134 Object base = asObject(baseConstant);
135 if (base == null) {
136 assert !compressed;
137 displacement += asRawPointer(baseConstant);
138 ret = runtime.getCompilerToVM().readUncompressedOop(displacement);
139 } else {
140 assert runtime.getConfig().useCompressedOops == compressed;
141 ret = UNSAFE.getObject(base, displacement);
142 }
143 assert verifyReadRawObject(ret, baseConstant, initialDisplacement, compressed);
144 return ret;
145 }
146
147 @Override
148 public JavaConstant readUnsafeConstant(JavaKind kind, JavaConstant baseConstant, long displacement) {
149 if (kind == null) {
150 throw new IllegalArgumentException("null JavaKind");
151 }
152 if (kind == JavaKind.Object) {
153 Object o = readRawObject(baseConstant, displacement, runtime.getConfig().useCompressedOops);
154 return HotSpotObjectConstantImpl.forObject(o);
155 } else {
156 int bits = kind.getByteCount() * Byte.SIZE;
157 return readPrimitiveConstant(kind, baseConstant, displacement, bits);
158 }
159 }
160
161 @Override
162 public JavaConstant readPrimitiveConstant(JavaKind kind, Constant baseConstant, long initialDisplacement, int bits) {
163 try {
164 long rawValue = readRawValue(baseConstant, initialDisplacement, bits);
165 switch (kind) {
166 case Boolean:
167 return JavaConstant.forBoolean(rawValue != 0);
168 case Byte:
169 return JavaConstant.forByte((byte) rawValue);
170 case Char:
171 return JavaConstant.forChar((char) rawValue);
172 case Short:
173 return JavaConstant.forShort((short) rawValue);
174 case Int:
175 return JavaConstant.forInt((int) rawValue);
176 case Long:
177 return JavaConstant.forLong(rawValue);
178 case Float:
179 return JavaConstant.forFloat(Float.intBitsToFloat((int) rawValue));
180 case Double:
181 return JavaConstant.forDouble(Double.longBitsToDouble(rawValue));
182 default:
183 throw new IllegalArgumentException("Unsupported kind: " + kind);
184 }
185 } catch (NullPointerException e) {
186 return null;
187 }
188 }
189
190 @Override
191 public JavaConstant readObjectConstant(Constant base, long displacement) {
192 if (!isValidObjectFieldDisplacement(base, displacement)) {
193 return null;
194 }
195 return HotSpotObjectConstantImpl.forObject(readRawObject(base, displacement, false));
196 }
197
198 @Override
199 public JavaConstant readNarrowOopConstant(Constant base, long displacement, CompressEncoding encoding) {
200 assert encoding.equals(runtime.getConfig().getOopEncoding()) : "unexpected oop encoding: " + encoding + " != " + runtime.getConfig().getOopEncoding();
201 return HotSpotObjectConstantImpl.forObject(readRawObject(base, displacement, true), true);
202 }
203
204 private HotSpotResolvedObjectTypeImpl readKlass(Constant base, long displacement, boolean compressed) {
205 assert (base instanceof HotSpotMetaspaceConstantImpl) || (base instanceof HotSpotObjectConstantImpl) : base.getClass();
206 Object baseObject = (base instanceof HotSpotMetaspaceConstantImpl) ? ((HotSpotMetaspaceConstantImpl) base).asResolvedJavaType() : ((HotSpotObjectConstantImpl) base).object();
207 return runtime.getCompilerToVM().getResolvedJavaType(baseObject, displacement, compressed);
208 }
209
210 @Override
211 public Constant readKlassPointerConstant(Constant base, long displacement) {
212 HotSpotResolvedObjectTypeImpl klass = readKlass(base, displacement, false);
213 if (klass == null) {
214 return JavaConstant.NULL_POINTER;
215 }
216 return HotSpotMetaspaceConstantImpl.forMetaspaceObject(klass, false);
217 }
218
219 @Override
220 public Constant readNarrowKlassPointerConstant(Constant base, long displacement, CompressEncoding encoding) {
221 HotSpotResolvedObjectTypeImpl klass = readKlass(base, displacement, true);
222 if (klass == null) {
223 return HotSpotCompressedNullConstant.COMPRESSED_NULL;
224 }
225 return HotSpotMetaspaceConstantImpl.forMetaspaceObject(klass, true);
226 }
227
228 @Override
229 public Constant readMethodPointerConstant(Constant base, long displacement) {
230 assert (base instanceof HotSpotObjectConstantImpl);
231 Object baseObject = ((HotSpotObjectConstantImpl) base).object();
232 HotSpotResolvedJavaMethodImpl method = runtime.getCompilerToVM().getResolvedJavaMethod(baseObject, displacement);
233 return HotSpotMetaspaceConstantImpl.forMetaspaceObject(method, false);
234 }
235
236 @Override
237 public Constant readSymbolConstant(Constant base, long displacement) {
238 int bits = runtime.getConfig().symbolPointerSize * Byte.SIZE;
239 long pointer = readRawValue(base, displacement, bits);
240 if (pointer == 0) {
241 return JavaConstant.NULL_POINTER;
242 } else {
243 String symbol = runtime.getCompilerToVM().getSymbol(pointer);
244 return new HotSpotSymbol(symbol, pointer).asConstant();
245 }
246 }
247 }