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