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 }