Refactored packagename to net.sourceforge.phpdt.internal.compiler.ast
[phpeclipse.git] / net.sourceforge.phpeclipse / src / net / sourceforge / phpdt / internal / compiler / ast / WhileStatement.java
index 01e956d..d1eb28b 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;
 
-/**
- * A While statement.
- * @author Matthieu Casanova
- */
+import net.sourceforge.phpdt.internal.compiler.ASTVisitor;
+import net.sourceforge.phpdt.internal.compiler.codegen.Label;
+import net.sourceforge.phpdt.internal.compiler.flow.FlowContext;
+import net.sourceforge.phpdt.internal.compiler.flow.FlowInfo;
+import net.sourceforge.phpdt.internal.compiler.flow.LoopingFlowContext;
+import net.sourceforge.phpdt.internal.compiler.impl.Constant;
+import net.sourceforge.phpdt.internal.compiler.lookup.BlockScope;
+import net.sourceforge.phpdt.internal.compiler.lookup.TypeBinding;
+
+
 public class WhileStatement extends Statement {
+       
+       public Expression condition;
+       public Statement action;
+       private Label breakLabel, continueLabel;
+       int preCondInitStateIndex = -1;
+       int condIfTrueInitStateIndex = -1;
+       int mergedInitStateIndex = -1;
+
+       public WhileStatement(Expression condition, Statement action, int s, int e) {
+
+               this.condition = condition;
+               this.action = action;
+               sourceStart = s;
+               sourceEnd = e;
+       }
+
+       public FlowInfo analyseCode(
+               BlockScope currentScope,
+               FlowContext flowContext,
+               FlowInfo flowInfo) {
+
+               breakLabel = new Label();
+               continueLabel = new Label(); 
+
+               Constant cst = this.condition.constant;
+               boolean isConditionTrue = cst != NotAConstant && cst.booleanValue() == true;
+               boolean isConditionFalse = cst != NotAConstant && cst.booleanValue() == false;
+
+               cst = this.condition.optimizedBooleanConstant();
+               boolean isConditionOptimizedTrue = cst != NotAConstant && cst.booleanValue() == true;
+               boolean isConditionOptimizedFalse = cst != NotAConstant && cst.booleanValue() == false;
+               
+               preCondInitStateIndex =
+                       currentScope.methodScope().recordInitializationStates(flowInfo);
+               LoopingFlowContext condLoopContext;
+               FlowInfo postCondInfo =
+                       this.condition.analyseCode(
+                               currentScope,
+                               (condLoopContext =
+                                       new LoopingFlowContext(flowContext, this, null, null, currentScope)),
+                               flowInfo);
+
+               LoopingFlowContext loopingContext;
+               FlowInfo actionInfo;
+//             if (action == null 
+//                     || (action.isEmptyBlock() && currentScope.environment().options.complianceLevel <= CompilerOptions.JDK1_3)) {
+//                     condLoopContext.complainOnFinalAssignmentsInLoop(currentScope, postCondInfo);
+//                     if (isConditionTrue) {
+//                             return FlowInfo.DEAD_END;
+//                     } else {
+//                             FlowInfo mergedInfo = postCondInfo.initsWhenFalse().unconditionalInits();
+//                             if (isConditionOptimizedTrue){
+//                                     mergedInfo.setReachMode(FlowInfo.UNREACHABLE);
+//                             }
+//                             mergedInitStateIndex =
+//                                     currentScope.methodScope().recordInitializationStates(mergedInfo);
+//                             return mergedInfo;
+//                     }
+//             } else {
+                       // in case the condition was inlined to false, record the fact that there is no way to reach any 
+                       // statement inside the looping action
+                       loopingContext =
+                               new LoopingFlowContext(
+                                       flowContext,
+                                       this,
+                                       breakLabel,
+                                       continueLabel,
+                                       currentScope);
+                       if (isConditionFalse) {
+                               actionInfo = FlowInfo.DEAD_END;
+                       } else {
+                               actionInfo = postCondInfo.initsWhenTrue().copy();
+                               if (isConditionOptimizedFalse){
+                                       actionInfo.setReachMode(FlowInfo.UNREACHABLE);
+                               }
+                       }
+
+                       // for computing local var attributes
+                       condIfTrueInitStateIndex =
+                               currentScope.methodScope().recordInitializationStates(
+                                       postCondInfo.initsWhenTrue());
+
+                       if (!actionInfo.complainIfUnreachable(action, currentScope, false)) {
+                               actionInfo = action.analyseCode(currentScope, loopingContext, actionInfo);
+                       }
+
+                       // code generation can be optimized when no need to continue in the loop
+                       if (!actionInfo.isReachable() && !loopingContext.initsOnContinue.isReachable()) {
+                               continueLabel = null;
+                       } else {
+                               // TODO: (philippe) should simplify in one Loop context
+                               condLoopContext.complainOnFinalAssignmentsInLoop(currentScope, postCondInfo);
+                               loopingContext.complainOnFinalAssignmentsInLoop(currentScope, actionInfo);
+                       }
+//             }
+
+               // infinite loop
+               FlowInfo mergedInfo;
+               if (isConditionOptimizedTrue) {
+                       mergedInitStateIndex =
+                               currentScope.methodScope().recordInitializationStates(
+                                       mergedInfo = loopingContext.initsOnBreak);
+                       return mergedInfo;
+               }
+
+               // end of loop: either condition false or break
+               mergedInfo =
+                       postCondInfo.initsWhenFalse().unconditionalInits().mergedWith(
+                               loopingContext.initsOnBreak);
+               if (isConditionOptimizedTrue && continueLabel == null){
+                       mergedInfo.setReachMode(FlowInfo.UNREACHABLE);
+               }
+               mergedInitStateIndex =
+                       currentScope.methodScope().recordInitializationStates(mergedInfo);
+               return mergedInfo;
+       }
+
+       /**
+        * While code generation
+        *
+        * @param currentScope net.sourceforge.phpdt.internal.compiler.lookup.BlockScope
+        * @param codeStream net.sourceforge.phpdt.internal.compiler.codegen.CodeStream
+        */
+//     public void generateCode(BlockScope currentScope, CodeStream codeStream) {
+//
+//             if ((bits & IsReachableMASK) == 0) {
+//                     return;
+//             }
+//             int pc = codeStream.position;
+//             breakLabel.codeStream = codeStream;
+//
+//             // generate condition
+//             if (continueLabel == null) {
+//                     // no need to reverse condition
+//                     if (condition.constant == NotAConstant) {
+//                             condition.generateOptimizedBoolean(
+//                                     currentScope,
+//                                     codeStream,
+//                                     null,
+//                                     breakLabel,
+//                                     true);
+//                     }
+//             } else {
+//                     continueLabel.codeStream = codeStream;
+//                     if (!(((condition.constant != NotAConstant)
+//                             && (condition.constant.booleanValue() == true))
+//                             || (action == null)
+//                             || action.isEmptyBlock())) {
+//                             int jumpPC = codeStream.position;
+//                             codeStream.goto_(continueLabel);
+//                             codeStream.recordPositionsFrom(jumpPC, condition.sourceStart);
+//                     }
+//             }
+//             // generate the action
+//             Label actionLabel;
+//             (actionLabel = new Label(codeStream)).place();
+//             if (action != null) {
+//                     // Required to fix 1PR0XVS: LFRE:WINNT - Compiler: variable table for method appears incorrect
+//                     if (condIfTrueInitStateIndex != -1) {
+//                             // insert all locals initialized inside the condition into the action generated prior to the condition
+//                             codeStream.addDefinitelyAssignedVariables(
+//                                     currentScope,
+//                                     condIfTrueInitStateIndex);
+//                     }
+//                     action.generateCode(currentScope, codeStream);
+//                     // May loose some local variable initializations : affecting the local variable attributes
+//                     if (preCondInitStateIndex != -1) {
+//                             codeStream.removeNotDefinitelyAssignedVariables(
+//                                     currentScope,
+//                                     preCondInitStateIndex);
+//                     }
+//
+//             }
+//             // output condition and branch back to the beginning of the repeated action
+//             if (continueLabel != null) {
+//                     continueLabel.place();
+//                     condition.generateOptimizedBoolean(
+//                             currentScope,
+//                             codeStream,
+//                             actionLabel,
+//                             null,
+//                             true);
+//             }
+//             breakLabel.place();
+//
+//             // May loose some local variable initializations : affecting the local variable attributes
+//             if (mergedInitStateIndex != -1) {
+//                     codeStream.removeNotDefinitelyAssignedVariables(
+//                             currentScope,
+//                             mergedInitStateIndex);
+//             }
+//             codeStream.recordPositionsFrom(pc, this.sourceStart);
+//     }
+
+       public void resetStateForCodeGeneration() {
+               if (this.breakLabel != null) {
+                       this.breakLabel.resetStateForCodeGeneration();
+               }
+               if (this.continueLabel != null) {
+                       this.continueLabel.resetStateForCodeGeneration();
+               }
+       }
+       public StringBuffer printStatement(int tab, StringBuffer output) {
+
+               printIndent(tab, output).append("while ("); //$NON-NLS-1$
+               condition.printExpression(0, output).append(')');
+               if (action == null)
+                       output.append(';');
+               else
+                       action.printStatement(tab + 1, output); 
+               return output;
+       }
+       public void resolve(BlockScope scope) {
+
+               TypeBinding type = condition.resolveTypeExpecting(scope, BooleanBinding);
+               condition.implicitWidening(type, type);
+               if (action != null)
+                       action.resolve(scope);
+       }
+
+       public String toString(int tab) {
+
+               String s = tabString(tab);
+               s = s + "while (" + condition.toStringExpression() + ")";       //$NON-NLS-1$ //$NON-NLS-2$
+               if (action == null)
+                       s = s + " {} ;"; //$NON-NLS-1$ 
+               else if (action instanceof Block)
+                       s = s + "\n" + action.toString(tab + 1); //$NON-NLS-1$
+               else
+                       s = s + " {\n" + action.toString(tab + 1) + "}"; //$NON-NLS-2$ //$NON-NLS-1$
+               return s;
+       }
+
+       public void traverse(
+           ASTVisitor visitor,
+               BlockScope blockScope) {
 
-  /** The condition expression. */
-  public Expression condition;
-  /** The action of the while. (it could be a block) */
-  public Statement action;
-
-  /**
-   * Create a While statement.
-   * @param condition the condition
-   * @param action the action
-   * @param sourceStart the starting offset
-   * @param sourceEnd the ending offset
-   */
-  public WhileStatement(Expression condition,
-                        Statement action,
-                        int sourceStart,
-                        int sourceEnd) {
-    super(sourceStart, sourceEnd);
-    this.condition = condition;
-    this.action = action;
-  }
-
-  /**
-   * Return the object into String.
-   * @param tab how many tabs (not used here
-   * @return a String
-   */
-  public String toString(int tab) {
-               final String s = tabString(tab);
-    final StringBuffer buff = new StringBuffer("while ("); //$NON-NLS-1$
-               buff.append(condition.toStringExpression()).append(")");        //$NON-NLS-1$
-               if (action == null) {
-                       buff.append(" {} ;"); //$NON-NLS-1$
-    } else {
-                       buff.append("\n").append(action.toString(tab + 1)); //$NON-NLS-1$
-    }
-               return buff.toString();
-  }
+               if (visitor.visit(this, blockScope)) {
+                       condition.traverse(visitor, blockScope);
+                       if (action != null)
+                               action.traverse(visitor, blockScope);
+               }
+               visitor.endVisit(this, blockScope);
+       }
 }