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 }