1 /* 2 * Copyright (c) 2011, 2019, 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.CompilerToVM.compilerToVM; 26 import static jdk.vm.ci.services.Services.IS_IN_NATIVE_IMAGE; 27 28 import jdk.vm.ci.code.InstalledCode; 29 import jdk.vm.ci.code.InvalidInstalledCodeException; 30 import jdk.vm.ci.common.JVMCIError; 31 import jdk.vm.ci.meta.JavaKind; 32 import jdk.vm.ci.meta.JavaType; 33 import jdk.vm.ci.meta.ResolvedJavaMethod; 34 35 /** 36 * Implementation of {@link InstalledCode} for code installed as an {@code nmethod}. The address of 37 * the {@code nmethod} is stored in {@link InstalledCode#address} and the value of 38 * {@code nmethod::verified_entry_point()} is in {@link InstalledCode#entryPoint}. 39 */ 40 public class HotSpotNmethod extends HotSpotInstalledCode { 41 42 /** 43 * This (indirect) {@code Method*} reference is safe since class redefinition preserves all 44 * methods associated with nmethods in the code cache. 45 */ 46 private final HotSpotResolvedJavaMethodImpl method; 47 48 /** 49 * Specifies whether the {@code nmethod} associated with this object is the code executed by 50 * default HotSpot linkage when a normal Java call to {@link #method} is made. That is, does 51 * {@code this.method.metadataHandle->_code} == {@code this.address}. If not, then the 52 * {@code nmethod} can only be invoked via a reference to this object. An example of this is the 53 * trampoline mechanism used by Truffle: https://goo.gl/LX88rZ. 54 */ 55 private final boolean isDefault; 56 57 /** 58 * Determines whether this object is in the oops table of the nmethod. 59 * <p> 60 * If this object is in the oops table, the VM uses the oops table entry to update this object's 61 * {@link #address} and {@link #entryPoint} fields when the state of the nmethod changes. The 62 * nmethod will be unloadable when this object dies. 63 * <p> 64 * Otherwise, the nmethod's unloadability is not changed when this object dies. 65 */ 66 boolean inOopsTable() { 67 return compileIdSnapshot != 0; 68 } 69 70 /** 71 * If this field is 0, this object is in the oops table of the nmethod. Otherwise, the value of 72 * the field records the nmethod's compile identifier. This value is used to confirm if an entry 73 * in the code cache retrieved by {@link #address} is indeed the nmethod represented by this 74 * object. 75 * 76 * @see #inOopsTable 77 */ 78 private final long compileIdSnapshot; 79 80 /** 81 * Identify the reason that caused this nmethod to be invalidated. 82 * A value of -1 means that the nmethod was not invalidated. 83 */ 84 private int invalidationReason; 85 86 HotSpotNmethod(HotSpotResolvedJavaMethodImpl method, String name, boolean isDefault, long compileId) { 87 super(name); 88 this.method = method; 89 this.isDefault = isDefault; 90 boolean inOopsTable = !IS_IN_NATIVE_IMAGE && !isDefault; 91 this.compileIdSnapshot = inOopsTable ? 0L : compileId; 92 this.invalidationReason = -1; 93 assert inOopsTable || compileId != 0L : this; 94 } 95 96 /** 97 * Attaches {@code log} to this object. If {@code log.managesFailedSpeculations() == true}, this 98 * ensures the failed speculation list lives at least as long as this object. 99 */ 100 public void setSpeculationLog(HotSpotSpeculationLog log) { 101 this.speculationLog = log; 102 } 103 104 /** 105 * The speculation log containing speculations embedded in the nmethod. 106 * 107 * If {@code speculationLog.managesFailedSpeculations() == true}, this field ensures the failed 108 * speculation list lives at least as long as this object. This prevents deoptimization from 109 * appending to an already freed list. 110 */ 111 @SuppressWarnings("unused") private HotSpotSpeculationLog speculationLog; 112 113 /** 114 * Determines if the nmethod associated with this object is the compiled entry point for 115 * {@link #getMethod()}. 116 */ 117 public boolean isDefault() { 118 return isDefault; 119 } 120 121 @Override 122 public boolean isValid() { 123 if (compileIdSnapshot != 0L) { 124 compilerToVM().updateHotSpotNmethod(this); 125 } 126 return super.isValid(); 127 } 128 129 public ResolvedJavaMethod getMethod() { 130 return method; 131 } 132 133 /** 134 * Invalidate this nmethod using the reason specified in {@code invalidationReason} and 135 * optionally deoptimize the method if {@code deoptimize} is set. 136 * @param deoptimize whether or not to deoptimize the method. 137 * @param invalidationReason invalidation reason code. 138 */ 139 public void invalidate(boolean deoptimize, int invalidationReason) { 140 compilerToVM().invalidateHotSpotNmethod(this, deoptimize, invalidationReason); 141 } 142 143 @Override 144 public void invalidate(boolean deoptimize) { 145 invalidate(deoptimize, jvmciInvalidationReason()); 146 } 147 148 @Override 149 public long getAddress() { 150 if (compileIdSnapshot != 0L) { 151 compilerToVM().updateHotSpotNmethod(this); 152 } 153 return super.getAddress(); 154 } 155 156 @Override 157 public long getEntryPoint() { 158 if (compileIdSnapshot != 0L) { 159 return 0; 160 } 161 return super.getEntryPoint(); 162 } 163 164 @Override 165 public String toString() { 166 return String.format("HotSpotNmethod[method=%s, codeBlob=0x%x, isDefault=%b, name=%s, inOopsTable=%s]", 167 method, getAddress(), isDefault, name, inOopsTable()); 168 } 169 170 private boolean checkArgs(Object... args) { 171 JavaType[] sig = method.toParameterTypes(); 172 assert args.length == sig.length : method.format("%H.%n(%p): expected ") + sig.length + " args, got " + args.length; 173 for (int i = 0; i < sig.length; i++) { 174 Object arg = args[i]; 175 if (arg == null) { 176 assert sig[i].getJavaKind() == JavaKind.Object : method.format("%H.%n(%p): expected arg ") + i + " to be Object, not " + sig[i]; 177 } else if (sig[i].getJavaKind() != JavaKind.Object) { 178 assert sig[i].getJavaKind().toBoxedJavaClass() == arg.getClass() : method.format("%H.%n(%p): expected arg ") + i + " to be " + sig[i] + ", not " + arg.getClass(); 179 } 180 } 181 return true; 182 } 183 184 /** 185 * {@inheritDoc} 186 * 187 * It's possible for the HotSpot runtime to sweep nmethods at any point in time. As a result, 188 * there is no guarantee that calling this method will execute the wrapped nmethod. Instead, it 189 * may end up executing the bytecode of the associated {@link #getMethod() Java method}. Only if 190 * {@link #isValid()} is {@code true} after returning can the caller be sure that the nmethod 191 * was executed. If {@link #isValid()} is {@code false}, then the only way to determine if the 192 * nmethod was executed is to test for some side-effect specific to the nmethod (e.g., update to 193 * a field) that is not performed by the bytecode of the associated {@link #getMethod() Java 194 * method}. 195 */ 196 @Override 197 public Object executeVarargs(Object... args) throws InvalidInstalledCodeException { 198 if (IS_IN_NATIVE_IMAGE) { 199 throw new HotSpotJVMCIUnsupportedOperationError("Cannot execute nmethod via mirror in native image"); 200 } 201 assert checkArgs(args); 202 return compilerToVM().executeHotSpotNmethod(args, this); 203 } 204 205 @Override 206 public long getStart() { 207 return isValid() ? super.getStart() : 0; 208 } 209 210 /** 211 * @return an integer representing the reason why this nmethod was invalidated. 212 */ 213 public int getInvalidationReason() { 214 return invalidationReason; 215 } 216 217 /** 218 * @return a String describing the reason why this nmethod was invalidated. 219 */ 220 public String getInvalidationReasonDescription() { 221 return compilerToVM().getInvalidationReasonDescription(this.getInvalidationReason()); 222 } 223 224 private static int jvmciInvalidationReason() { 225 return HotSpotJVMCIRuntime.runtime().config.getConstant("nmethod::InvalidationReason::JVMCI_INVALIDATE", Integer.class); 226 } 227 }