1 /*
   2  * Copyright (c) 2012, 2014, 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.*;
  26 
  27 /**
  28  * Provides access to the metadata of a class typically provided in a class file.
  29  */
  30 public interface MetaAccessProvider {
  31 
  32     /**
  33      * Returns the resolved Java type representing a given Java class.
  34      *
  35      * @param clazz the Java class object
  36      * @return the resolved Java type object
  37      */
  38     ResolvedJavaType lookupJavaType(Class<?> clazz);
  39 
  40     /**
  41      * Returns the resolved Java types representing some given Java classes.
  42      *
  43      * @param classes the Java class objects
  44      * @return the resolved Java type objects
  45      */
  46     default ResolvedJavaType[] lookupJavaTypes(Class<?>[] classes) {
  47         ResolvedJavaType[] result = new ResolvedJavaType[classes.length];
  48         for (int i = 0; i < result.length; i++) {
  49             result[i] = lookupJavaType(classes[i]);
  50         }
  51         return result;
  52     }
  53 
  54     /**
  55      * Provides the {@link ResolvedJavaMethod} for a {@link Method} or {@link Constructor} obtained
  56      * via reflection.
  57      */
  58     ResolvedJavaMethod lookupJavaMethod(Executable reflectionMethod);
  59 
  60     /**
  61      * Provides the {@link ResolvedJavaField} for a {@link Field} obtained via reflection.
  62      */
  63     ResolvedJavaField lookupJavaField(Field reflectionField);
  64 
  65     /**
  66      * Returns the resolved Java type of the given {@link JavaConstant} object.
  67      *
  68      * @return {@code null} if {@code constant.isNull() || !constant.kind.isObject()}
  69      */
  70     ResolvedJavaType lookupJavaType(JavaConstant constant);
  71 
  72     /**
  73      * Returns the number of bytes occupied by this constant value or constant object.
  74      *
  75      * @param constant the constant whose bytes should be measured
  76      * @return the number of bytes occupied by this constant
  77      */
  78     long getMemorySize(JavaConstant constant);
  79 
  80     /**
  81      * Parses a <a
  82      * href="http://docs.oracle.com/javase/specs/jvms/se7/html/jvms-4.html#jvms-4.3.3">method
  83      * descriptor</a> into a {@link Signature}. The behavior of this method is undefined if the
  84      * method descriptor is not well formed.
  85      */
  86     Signature parseMethodDescriptor(String methodDescriptor);
  87 
  88     /**
  89      * Encodes a deoptimization action and a deoptimization reason in an integer value.
  90      *
  91      * @param debugId an integer that can be used to track the origin of a deoptimization at
  92      *            runtime. There is no guarantee that the runtime will use this value. The runtime
  93      *            may even keep fewer than 32 bits.
  94      *
  95      * @return the encoded value as an integer
  96      */
  97     JavaConstant encodeDeoptActionAndReason(DeoptimizationAction action, DeoptimizationReason reason, int debugId);
  98 
  99     DeoptimizationReason decodeDeoptReason(JavaConstant constant);
 100 
 101     DeoptimizationAction decodeDeoptAction(JavaConstant constant);
 102 
 103     int decodeDebugId(JavaConstant constant);
 104 }