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   1 /*******************************************************************************
   2  * Copyright (c) 2000, 2003 IBM Corporation and others.
   3  * All rights reserved. This program and the accompanying materials
   4  * are made available under the terms of the Common Public License v1.0
   5  * which accompanies this distribution, and is available at
   6  * http://www.eclipse.org/legal/cpl-v10.html
   7  *
   8  * Contributors:
   9  *     IBM Corporation - initial API and implementation
  10  *******************************************************************************/
  11 package net.sourceforge.phpdt.internal.compiler.flow;
  12
  13 import java.util.ArrayList;
  14
  15 import net.sourceforge.phpdt.internal.compiler.codegen.ObjectCache;
  16 import net.sourceforge.phpdt.internal.compiler.lookup.BlockScope;
  17 import net.sourceforge.phpdt.internal.compiler.lookup.CompilerModifiers;
  18 import net.sourceforge.phpdt.internal.compiler.lookup.MethodScope;
  19 import net.sourceforge.phpdt.internal.compiler.lookup.ReferenceBinding;
  20 import net.sourceforge.phpdt.internal.compiler.lookup.Scope;
  21 import net.sourceforge.phpdt.internal.compiler.lookup.TypeBinding;
  22 import net.sourceforge.phpeclipse.internal.compiler.ast.ASTNode;
  23 import net.sourceforge.phpeclipse.internal.compiler.ast.AbstractMethodDeclaration;
  24 import net.sourceforge.phpeclipse.internal.compiler.ast.TryStatement;
  25
  26 /**
  27  * Reflects the context of code analysis, keeping track of enclosing
  28  *      try statements, exception handlers, etc...
  29  */
  30 public class ExceptionHandlingFlowContext extends FlowContext {
  31
  32         public ReferenceBinding[] handledExceptions;
  33
  34         public final static int BitCacheSize = 32; // 32 bits per int
  35         int[] isReached;
  36         int[] isNeeded;
  37         UnconditionalFlowInfo[] initsOnExceptions;
  38         ObjectCache indexes = new ObjectCache();
  39         boolean isMethodContext;
  40
  41         public UnconditionalFlowInfo initsOnReturn;
  42
  43         // for dealing with anonymous constructor thrown exceptions
  44         public ArrayList extendedExceptions;
  45
  46         public ExceptionHandlingFlowContext(
  47                 FlowContext parent,
  48                 ASTNode associatedNode,
  49                 ReferenceBinding[] handledExceptions,
  50                 BlockScope scope,
  51                 UnconditionalFlowInfo flowInfo) {
  52
  53                 super(parent, associatedNode);
  54                 isMethodContext = scope == scope.methodScope();
  55                 this.handledExceptions = handledExceptions;
  56                 int count = handledExceptions.length, cacheSize = (count / BitCacheSize) + 1;
  57                 this.isReached = new int[cacheSize]; // none is reached by default
  58                 this.isNeeded = new int[cacheSize]; // none is needed by default
  59                 this.initsOnExceptions = new UnconditionalFlowInfo[count];
  60                 for (int i = 0; i < count; i++) {
  61                         this.indexes.put(handledExceptions[i], i); // key type  -> value index
  62                         boolean isUnchecked =
  63                                 (scope.compareUncheckedException(handledExceptions[i]) != NotRelated);
  64                         int cacheIndex = i / BitCacheSize, bitMask = 1 << (i % BitCacheSize);
  65                         if (isUnchecked) {
  66                                 isReached[cacheIndex] |= bitMask;
  67                                 this.initsOnExceptions[i] = flowInfo.copy().unconditionalInits();
  68                         } else {
  69                                 this.initsOnExceptions[i] = FlowInfo.DEAD_END;
  70                         }
  71                 }
  72                 System.arraycopy(this.isReached, 0, this.isNeeded, 0, cacheSize);
  73                 this.initsOnReturn = FlowInfo.DEAD_END;
  74         }
  75
  76
  77 //      public void complainIfUnusedExceptionHandlers(
  78 //              ASTNode[] exceptionHandlers,
  79 //              BlockScope scope,
  80 //              TryStatement tryStatement) {
  81 //              // report errors for unreachable exception handlers
  82 //              for (int i = 0, count = handledExceptions.length; i < count; i++) {
  83 //                      int index = indexes.get(handledExceptions[i]);
  84 //                      int cacheIndex = index / BitCacheSize;
  85 //                      int bitMask = 1 << (index % BitCacheSize);
  86 //                      if ((isReached[cacheIndex] & bitMask) == 0) {
  87 //                              scope.problemReporter().unreachableExceptionHandler(
  88 //                                      handledExceptions[index],
  89 //                                      exceptionHandlers[index]);
  90 //                      } else {
  91 //                              if ((isNeeded[cacheIndex] & bitMask) == 0) {
  92 //                                      scope.problemReporter().maskedExceptionHandler(
  93 //                                              handledExceptions[index],
  94 //                                              exceptionHandlers[index]);
  95 //                              }
  96 //                      }
  97 //              }
  98 //              // will optimized out unnecessary catch block during code gen
  99 //              tryStatement.preserveExceptionHandler = isNeeded;
 100 //      }
 101
 102         public String individualToString() {
 103
 104                 StringBuffer buffer = new StringBuffer("Exception flow context"); //$NON-NLS-1$
 105                 int length = handledExceptions.length;
 106                 for (int i = 0; i < length; i++) {
 107                         int cacheIndex = i / BitCacheSize;
 108                         int bitMask = 1 << (i % BitCacheSize);
 109                         buffer.append('[').append(handledExceptions[i].readableName());
 110                         if ((isReached[cacheIndex] & bitMask) != 0) {
 111                                 if ((isNeeded[cacheIndex] & bitMask) == 0) {
 112                                         buffer.append("-masked"); //$NON-NLS-1$
 113                                 } else {
 114                                         buffer.append("-reached"); //$NON-NLS-1$
 115                                 }
 116                         } else {
 117                                 buffer.append("-not reached"); //$NON-NLS-1$
 118                         }
 119                         buffer.append('-').append(initsOnExceptions[i].toString()).append(']');
 120                 }
 121                 buffer.append("[initsOnReturn -").append(initsOnReturn.toString()).append(']'); //$NON-NLS-1$
 122                 return buffer.toString();
 123         }
 124
 125         public UnconditionalFlowInfo initsOnException(ReferenceBinding exceptionType) {
 126
 127                 int index;
 128                 if ((index = indexes.get(exceptionType)) < 0) {
 129                         return FlowInfo.DEAD_END;
 130                 }
 131                 return initsOnExceptions[index];
 132         }
 133
 134         public UnconditionalFlowInfo initsOnReturn(){
 135                 return this.initsOnReturn;
 136         }
 137
 138         public void recordHandlingException(
 139                 ReferenceBinding exceptionType,
 140                 UnconditionalFlowInfo flowInfo,
 141                 TypeBinding raisedException,
 142                 ASTNode invocationSite,
 143                 boolean wasAlreadyDefinitelyCaught) {
 144
 145                 int index = indexes.get(exceptionType);
 146                 // if already flagged as being reached (unchecked exception handler)
 147                 int cacheIndex = index / BitCacheSize;
 148                 int bitMask = 1 << (index % BitCacheSize);
 149                 if (!wasAlreadyDefinitelyCaught) {
 150                         this.isNeeded[cacheIndex] |= bitMask;
 151                 }
 152                 this.isReached[cacheIndex] |= bitMask;
 153
 154                 initsOnExceptions[index] =
 155                         initsOnExceptions[index] == FlowInfo.DEAD_END
 156                                 ? flowInfo.copy().unconditionalInits()
 157                                 : initsOnExceptions[index].mergedWith(flowInfo);
 158         }
 159
 160         public void recordReturnFrom(FlowInfo flowInfo) {
 161
 162                 if (!flowInfo.isReachable()) return;
 163                 if (initsOnReturn == FlowInfo.DEAD_END) {
 164                         initsOnReturn = flowInfo.copy().unconditionalInits();
 165                 } else {
 166                         initsOnReturn = initsOnReturn.mergedWith(flowInfo.unconditionalInits());
 167                 }
 168         }
 169
 170         /*
 171          * Compute a merged list of unhandled exception types (keeping only the most generic ones).
 172          * This is necessary to add synthetic thrown exceptions for anonymous type constructors (JLS 8.6).
 173          */
 174         public void mergeUnhandledException(TypeBinding newException){
 175
 176                 if (this.extendedExceptions == null){
 177                         this.extendedExceptions = new ArrayList(5);
 178                         for (int i = 0; i < this.handledExceptions.length; i++){
 179                                 this.extendedExceptions.add(this.handledExceptions[i]);
 180                         }
 181                 }
 182
 183                 boolean isRedundant = false;
 184
 185                 for(int i = this.extendedExceptions.size()-1; i >= 0; i--){
 186                         switch(Scope.compareTypes(newException, (TypeBinding)this.extendedExceptions.get(i))){
 187                                 case MoreGeneric :
 188                                         this.extendedExceptions.remove(i);
 189                                         break;
 190                                 case EqualOrMoreSpecific :
 191                                         isRedundant = true;
 192                                         break;
 193                                 case NotRelated :
 194                                         break;
 195                         }
 196                 }
 197                 if (!isRedundant){
 198                         this.extendedExceptions.add(newException);
 199                 }
 200         }
 201 }