1 /*
   2  * Copyright (c) 2012, 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.meta;
  24 
  25 import java.lang.reflect.Constructor;
  26 import java.lang.reflect.Executable;
  27 import java.lang.reflect.Field;
  28 import java.lang.reflect.Method;
  29 
  30 import jdk.vm.ci.meta.SpeculationLog.Speculation;
  31 
  32 /**
  33  * Provides access to the metadata of a class typically provided in a class file.
  34  */
  35 public interface MetaAccessProvider {
  36 
  37     /**
  38      * Returns the resolved Java type representing a given Java class.
  39      *
  40      * @param clazz the Java class object
  41      * @return the resolved Java type object
  42      */
  43     ResolvedJavaType lookupJavaType(Class<?> clazz);
  44 
  45     /**
  46      * Returns the resolved Java types representing some given Java classes.
  47      *
  48      * @param classes the Java class objects
  49      * @return the resolved Java type objects
  50      */
  51     default ResolvedJavaType[] lookupJavaTypes(Class<?>[] classes) {
  52         ResolvedJavaType[] result = new ResolvedJavaType[classes.length];
  53         for (int i = 0; i < result.length; i++) {
  54             result[i] = lookupJavaType(classes[i]);
  55         }
  56         return result;
  57     }
  58 
  59     /**
  60      * Provides the {@link ResolvedJavaMethod} for a {@link Method} or {@link Constructor} obtained
  61      * via reflection.
  62      */
  63     ResolvedJavaMethod lookupJavaMethod(Executable reflectionMethod);
  64 
  65     /**
  66      * Provides the {@link ResolvedJavaField} for a {@link Field} obtained via reflection.
  67      */
  68     ResolvedJavaField lookupJavaField(Field reflectionField);
  69 
  70     /**
  71      * Returns the resolved Java type of the given {@link JavaConstant} object.
  72      *
  73      * @return {@code null} if {@code constant.isNull() || !constant.kind.isObject()}
  74      */
  75     ResolvedJavaType lookupJavaType(JavaConstant constant);
  76 
  77     /**
  78      * Returns the number of bytes occupied by this constant value or constant object.
  79      *
  80      * @param constant the constant whose bytes should be measured
  81      * @return the number of bytes occupied by this constant
  82      */
  83     long getMemorySize(JavaConstant constant);
  84 
  85     /**
  86      * Parses a
  87      * <a href="http://docs.oracle.com/javase/specs/jvms/se7/html/jvms-4.html#jvms-4.3.3">method
  88      * descriptor</a> into a {@link Signature}.
  89      *
  90      * @throws IllegalArgumentException if the method descriptor is not well formed
  91      */
  92     Signature parseMethodDescriptor(String methodDescriptor);
  93 
  94     /**
  95      * Encodes a deoptimization action and a deoptimization reason in an integer value.
  96      *
  97      * @param debugId an integer that can be used to track the origin of a deoptimization at
  98      *            runtime. There is no guarantee that the runtime will use this value. The runtime
  99      *            may even keep fewer than 32 bits.
 100      *
 101      * @return the encoded value as an integer
 102      */
 103     JavaConstant encodeDeoptActionAndReason(DeoptimizationAction action, DeoptimizationReason reason, int debugId);
 104 
 105     /**
 106      * Gets a constant that denotes {@code speculation}. The constant can passed to the
 107      * deoptimization handler (e.g., through a thread local) to indicate a failed speculation.
 108      */
 109     JavaConstant encodeSpeculation(Speculation speculation);
 110 
 111     /**
 112      * Decodes {@code constant} back to a {@link Speculation} object.
 113      *
 114      * @throws IllegalArgumentException if {@code constant} can only be decoded through a
 115      *             {@link SpeculationLog} and {@code speculationLog} does not contain the
 116      *             speculation denoted by {@code constant}
 117      */
 118     Speculation decodeSpeculation(JavaConstant constant, SpeculationLog speculationLog);
 119 
 120     DeoptimizationReason decodeDeoptReason(JavaConstant constant);
 121 
 122     DeoptimizationAction decodeDeoptAction(JavaConstant constant);
 123 
 124     int decodeDebugId(JavaConstant constant);
 125 
 126     int getArrayBaseOffset(JavaKind elementKind);
 127 
 128     int getArrayIndexScale(JavaKind elementKind);
 129 }