Refactored packagename to net.sourceforge.phpdt.internal.compiler.ast
[phpeclipse.git] / net.sourceforge.phpeclipse / src / net / sourceforge / phpdt / internal / compiler / ast / ReturnStatement.java
index a30be75..149f034 100644 (file)
+/***********************************************************************************************************************************
+ * Copyright (c) 2000, 2003 IBM Corporation and others. All rights reserved. This program and the accompanying materials are made
+ * available under the terms of the Common Public License v1.0 which accompanies this distribution, and is available at
+ * http://www.eclipse.org/legal/cpl-v10.html
+ * 
+ * Contributors: IBM Corporation - initial API and implementation
+ **********************************************************************************************************************************/
 package net.sourceforge.phpdt.internal.compiler.ast;
 
-import net.sourceforge.phpdt.internal.compiler.ast.declarations.VariableUsage;
+import net.sourceforge.phpdt.internal.compiler.ASTVisitor;
+import net.sourceforge.phpdt.internal.compiler.flow.FlowContext;
+import net.sourceforge.phpdt.internal.compiler.flow.FlowInfo;
+import net.sourceforge.phpdt.internal.compiler.flow.InitializationFlowContext;
+import net.sourceforge.phpdt.internal.compiler.lookup.BlockScope;
+import net.sourceforge.phpdt.internal.compiler.lookup.LocalVariableBinding;
+import net.sourceforge.phpdt.internal.compiler.lookup.MethodBinding;
+import net.sourceforge.phpdt.internal.compiler.lookup.MethodScope;
+import net.sourceforge.phpdt.internal.compiler.lookup.TypeBinding;
 
-import java.util.List;
-import java.util.ArrayList;
-
-/**
- * A return statement.
- * @author Matthieu Casanova
- */
 public class ReturnStatement extends Statement {
-
   public Expression expression;
 
-  public ReturnStatement(final Expression expression, final int sourceStart, final int sourceEnd) {
-    super(sourceStart, sourceEnd);
-    this.expression = expression;
+  public TypeBinding expressionType;
+
+  public boolean isSynchronized;
+
+  public ASTNode[] subroutines;
+
+  public LocalVariableBinding saveValueVariable;
+
+  public ReturnStatement(Expression expr, int s, int e) {
+    sourceStart = s;
+    sourceEnd = e;
+    expression = expr;
   }
 
-  public String toString(final int tab) {
-    final String s = tabString(tab);
-    if (expression == null) {
-      return s + "return";//$NON-NLS-1$
+  public FlowInfo analyseCode(BlockScope currentScope, FlowContext flowContext, FlowInfo flowInfo) { // here requires to generate a
+                                                                                                     // sequence of finally blocks
+                                                                                                     // invocations depending
+                                                                                                     // corresponding
+    // to each of the traversed try statements, so that execution will terminate properly.
+
+    // lookup the label, this should answer the returnContext
+
+    if (expression != null) {
+      flowInfo = expression.analyseCode(currentScope, flowContext, flowInfo);
     }
-    return s + "return " + expression.toStringExpression();//$NON-NLS-1$
-  }
+    // compute the return sequence (running the finally blocks)
+    FlowContext traversedContext = flowContext;
+    int subIndex = 0, maxSub = 5;
+    boolean saveValueNeeded = false;
+    boolean hasValueToSave = expression != null && expression.constant == NotAConstant;
+    do {
+      ASTNode sub;
+      if ((sub = traversedContext.subRoutine()) != null) {
+        if (this.subroutines == null) {
+          this.subroutines = new ASTNode[maxSub];
+        }
+        if (subIndex == maxSub) {
+          System.arraycopy(this.subroutines, 0, (this.subroutines = new ASTNode[maxSub *= 2]), 0, subIndex); // grow
+        }
+        this.subroutines[subIndex++] = sub;
+        if (sub.cannotReturn()) {
+          saveValueNeeded = false;
+          break;
+        }
+      }
+      traversedContext.recordReturnFrom(flowInfo.unconditionalInits());
 
-    /**
-   * Get the variables from outside (parameters, globals ...)
-   * @return the variables from outside
-   */
-  public List getOutsideVariable() {
-    return new ArrayList();
+      ASTNode node = traversedContext.associatedNode;
+//      if ((node = traversedContext.associatedNode) instanceof SynchronizedStatement) {
+//        isSynchronized = true;
+//
+//      } else 
+      if (node instanceof TryStatement) {
+        TryStatement tryStatement = (TryStatement) node;
+        flowInfo.addInitializationsFrom(tryStatement.subRoutineInits); // collect inits
+        if (hasValueToSave) {
+          if (this.saveValueVariable == null) { // closest subroutine secret variable is used
+            prepareSaveValueLocation(tryStatement);
+          }
+          saveValueNeeded = true;
+        }
+
+      } else if (traversedContext instanceof InitializationFlowContext) {
+        currentScope.problemReporter().cannotReturnInInitializer(this);
+        return FlowInfo.DEAD_END;
+      }
+    } while ((traversedContext = traversedContext.parent) != null);
+
+    // resize subroutines
+    if ((subroutines != null) && (subIndex != maxSub)) {
+      System.arraycopy(subroutines, 0, (subroutines = new ASTNode[subIndex]), 0, subIndex);
+    }
+
+    // secret local variable for return value (note that this can only occur in a real method)
+    if (saveValueNeeded) {
+      if (this.saveValueVariable != null) {
+        this.saveValueVariable.useFlag = LocalVariableBinding.USED;
+      }
+    } else {
+      this.saveValueVariable = null;
+      if ((!isSynchronized) && (expressionType == BooleanBinding)) {
+        this.expression.bits |= ValueForReturnMASK;
+      }
+    }
+    return FlowInfo.DEAD_END;
   }
 
   /**
-   * get the modified variables.
-   * @return the variables modified
+   * Retrun statement code generation
+   * 
+   * generate the finallyInvocationSequence.
+   * 
+   * @param currentScope
+   *          net.sourceforge.phpdt.internal.compiler.lookup.BlockScope
+   * @param codeStream
+   *          net.sourceforge.phpdt.internal.compiler.codegen.CodeStream
    */
-  public List getModifiedVariable() {
-    return expression.getModifiedVariable();
-  }
-
+  //public void generateCode(BlockScope currentScope, CodeStream codeStream) {
+  //   if ((bits & IsReachableMASK) == 0) {
+  //           return;
+  //   }
+  //   int pc = codeStream.position;
+  //   // generate the expression
+  //   if ((expression != null) && (expression.constant == NotAConstant)) {
+  //           expression.generateCode(currentScope, codeStream, needValue()); // no value needed if non-returning subroutine
+  //           generateStoreSaveValueIfNecessary(codeStream);
+  //   }
+  //   
+  //   // generation of code responsible for invoking the finally blocks in sequence
+  //   if (subroutines != null) {
+  //           for (int i = 0, max = subroutines.length; i < max; i++) {
+  //                   ASTNode sub;
+  //                   if ((sub = subroutines[i]) instanceof SynchronizedStatement) {
+  //                           codeStream.load(((SynchronizedStatement) sub).synchroVariable);
+  //                           codeStream.monitorexit();
+  //                   } else {
+  //                           TryStatement trySub = (TryStatement) sub;
+  //                           if (trySub.subRoutineCannotReturn) {
+  //                                   codeStream.goto_(trySub.subRoutineStartLabel);
+  //                                   codeStream.recordPositionsFrom(pc, this.sourceStart);
+  //                                   return;
+  //                           } else {
+  //                                   codeStream.jsr(trySub.subRoutineStartLabel);
+  //                           }
+  //                   }
+  //           }
+  //   }
+  //   if (saveValueVariable != null) codeStream.load(saveValueVariable);
+  //   
+  //   if ((expression != null) && (expression.constant != NotAConstant)) {
+  //           codeStream.generateConstant(expression.constant, expression.implicitConversion);
+  //           generateStoreSaveValueIfNecessary(codeStream);
+  //   }
+  //   // output the suitable return bytecode or wrap the value inside a descriptor for doits
+  //   this.generateReturnBytecode(codeStream);
+  //   
+  //   codeStream.recordPositionsFrom(pc, this.sourceStart);
+  //}
   /**
-   * Get the variables used.
-   * @return the variables used
+   * Dump the suitable return bytecode for a return statement
+   *  
    */
-  public List getUsedVariable() {
-    return expression.getUsedVariable();
+  //public void generateReturnBytecode(CodeStream codeStream) {
+  //
+  //   if (expression == null) {
+  //           codeStream.return_();
+  //   } else {
+  //           switch (expression.implicitConversion >> 4) {
+  //                   case T_boolean :
+  //                   case T_int :
+  //                           codeStream.ireturn();
+  //                           break;
+  //                   case T_float :
+  //                           codeStream.freturn();
+  //                           break;
+  //                   case T_long :
+  //                           codeStream.lreturn();
+  //                           break;
+  //                   case T_double :
+  //                           codeStream.dreturn();
+  //                           break;
+  //                   default :
+  //                           codeStream.areturn();
+  //           }
+  //   }
+  //}
+  //public void generateStoreSaveValueIfNecessary(CodeStream codeStream){
+  //   if (saveValueVariable != null) codeStream.store(saveValueVariable, false);
+  //}
+  public boolean needValue() {
+    return (subroutines == null) || (saveValueVariable != null) || isSynchronized;
+  }
+
+  public void prepareSaveValueLocation(TryStatement targetTryStatement) {
+
+    this.saveValueVariable = targetTryStatement.secretReturnValue;
+  }
+
+  public void resolve(BlockScope scope) {
+    MethodScope methodScope = scope.methodScope();
+    MethodBinding methodBinding;
+    TypeBinding methodType = (methodScope.referenceContext instanceof AbstractMethodDeclaration) ? ((methodBinding = ((AbstractMethodDeclaration) methodScope.referenceContext).binding) == null ? null
+        : methodBinding.returnType)
+        : VoidBinding;
+    if (methodType == VoidBinding) {
+      // the expression should be null
+      if (expression == null)
+        return;
+      if ((expressionType = expression.resolveType(scope)) != null)
+        scope.problemReporter().attemptToReturnNonVoidExpression(this, expressionType);
+      return;
+    }
+    if (expression == null) {
+      if (methodType != null)
+        scope.problemReporter().shouldReturn(methodType, this);
+      return;
+    }
+    if ((expressionType = expression.resolveType(scope)) == null)
+      return;
+
+    if (methodType != null && expression.isConstantValueOfTypeAssignableToType(expressionType, methodType)) {
+      // dealing with constant
+      expression.implicitWidening(methodType, expressionType);
+      return;
+    }
+    if (expressionType == VoidBinding) {
+      scope.problemReporter().attemptToReturnVoidValue(this);
+      return;
+    }
+    if (methodType != null && expressionType.isCompatibleWith(methodType)) {
+      expression.implicitWidening(methodType, expressionType);
+      return;
+    }
+    if (methodType != null) {
+      scope.problemReporter().typeMismatchErrorActualTypeExpectedType(expression, expressionType, methodType);
+    }
+  }
+
+  public StringBuffer printStatement(int tab, StringBuffer output) {
+
+    printIndent(tab, output).append("return "); //$NON-NLS-1$
+    if (expression != null)
+      expression.printExpression(0, output);
+    return output.append(';');
+  }
+
+  public String toString(int tab) {
+
+    String s = tabString(tab);
+    s = s + "return "; //$NON-NLS-1$
+    if (expression != null)
+      s = s + expression.toStringExpression();
+    return s;
+  }
+
+  public void traverse(ASTVisitor visitor, BlockScope scope) {
+    if (visitor.visit(this, scope)) {
+      if (expression != null)
+        expression.traverse(visitor, scope);
+    }
+    visitor.endVisit(this, scope);
   }
-}
+}
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