Refactored packagename to net.sourceforge.phpdt.internal.compiler.ast
[phpeclipse.git] / net.sourceforge.phpeclipse / src / net / sourceforge / phpdt / internal / compiler / ast / IfStatement.java
index aa61a55..7959ba7 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;
 
-/**
- * @author Matthieu Casanova
- */
+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.impl.Constant;
+import net.sourceforge.phpdt.internal.compiler.lookup.BlockScope;
+import net.sourceforge.phpdt.internal.compiler.lookup.TypeBinding;
+
 public class IfStatement extends Statement {
+       
+       //this class represents the case of only one statement in 
+       //either else and/or then branches.
+
+       public Expression condition;
+       public Statement thenStatement;
+       public Statement elseStatement;
+       public Expression[] elseifConditions;
+       public Statement[] elseifStatements;
+       public boolean checkUnreachable;
+       boolean thenExit;
+       
+
+       // for local variables table attributes
+       int thenInitStateIndex = -1;
+       int elseInitStateIndex = -1;
+       int mergedInitStateIndex = -1;
+
+       public IfStatement(
+               Expression condition,
+               Statement thenStatement,
+               int s,
+               int e) {
+
+               this.condition = condition;
+               this.thenStatement = thenStatement;
+               sourceStart = s;
+               sourceEnd = e;
+               checkUnreachable = true;
+       }
+
+       public IfStatement(
+               Expression condition,
+               Statement thenStatement,
+               Statement elseStatement,
+               int s,
+               int e) {
+
+               this.condition = condition;
+               this.thenStatement = thenStatement;
+               this.elseStatement = elseStatement;
+               sourceEnd = e;
+               sourceStart = s;
+               checkUnreachable = true;
+       }
+
+       public FlowInfo analyseCode(
+               BlockScope currentScope,
+               FlowContext flowContext,
+               FlowInfo flowInfo) {
+
+               // process the condition
+               flowInfo = condition.analyseCode(currentScope, flowContext, flowInfo);
+
+               Constant cst = this.condition.optimizedBooleanConstant();
+               boolean isConditionOptimizedTrue = cst != NotAConstant && cst.booleanValue() == true;
+               boolean isConditionOptimizedFalse = cst != NotAConstant && cst.booleanValue() == false;
+               
+               // process the THEN part
+               FlowInfo thenFlowInfo = flowInfo.initsWhenTrue().copy();
+               if (isConditionOptimizedFalse) {
+                       thenFlowInfo.setReachMode(FlowInfo.UNREACHABLE); 
+               }
+               if (this.thenStatement != null) {
+                       // Save info for code gen
+                       thenInitStateIndex =
+                               currentScope.methodScope().recordInitializationStates(thenFlowInfo);
+                       if (!thenFlowInfo.complainIfUnreachable(thenStatement, currentScope, false)) {
+                               thenFlowInfo =
+                                       thenStatement.analyseCode(currentScope, flowContext, thenFlowInfo);
+                       }
+               };
+               // optimizing the jump around the ELSE part
+               this.thenExit = !thenFlowInfo.isReachable();
+
+               // process the ELSE part
+               FlowInfo elseFlowInfo = flowInfo.initsWhenFalse().copy();
+               if (isConditionOptimizedTrue) {
+                       elseFlowInfo.setReachMode(FlowInfo.UNREACHABLE); 
+               }
+               if (this.elseStatement != null) {
+                       // Save info for code gen
+                       elseInitStateIndex =
+                               currentScope.methodScope().recordInitializationStates(elseFlowInfo);
+                       if (!elseFlowInfo.complainIfUnreachable(elseStatement, currentScope, false)) {
+                               elseFlowInfo =
+                                       elseStatement.analyseCode(currentScope, flowContext, elseFlowInfo);
+                       }
+               }
+
+               boolean elseExit = !elseFlowInfo.isReachable();
+               
+               // merge THEN & ELSE initializations
+               FlowInfo mergedInfo;
+//             if (isConditionOptimizedTrue){
+//                     if (!this.thenExit) {
+//                             mergedInfo = thenFlowInfo;
+//                     } else {
+//                             mergedInfo = elseFlowInfo.setReachMode(FlowInfo.UNREACHABLE);
+//                     }
+//
+//             } else if (isConditionOptimizedFalse) {
+//                     if (!elseExit) {
+//                             mergedInfo = elseFlowInfo;
+//                     } else {
+//                             mergedInfo = thenFlowInfo.setReachMode(FlowInfo.UNREACHABLE);
+//                     }
+//
+//             } else {
+//                     mergedInfo = thenFlowInfo.mergedWith(elseFlowInfo.unconditionalInits());
+//             }
+               if (isConditionOptimizedTrue){
+                       if (!this.thenExit) {
+                               mergedInfo = thenFlowInfo.addPotentialInitializationsFrom(elseFlowInfo);
+                       } else {
+                               mergedInfo = elseFlowInfo.setReachMode(FlowInfo.UNREACHABLE);
+                       }
+
+               } else if (isConditionOptimizedFalse) {
+                       if (!elseExit) {
+                               mergedInfo = elseFlowInfo.addPotentialInitializationsFrom(thenFlowInfo);
+                       } else {
+                               mergedInfo = thenFlowInfo.setReachMode(FlowInfo.UNREACHABLE);
+                       }
+
+               } else {
+                       mergedInfo = thenFlowInfo.mergedWith(elseFlowInfo.unconditionalInits());
+               }
+
+               mergedInitStateIndex =
+                       currentScope.methodScope().recordInitializationStates(mergedInfo);
+               return mergedInfo;
+       }
+
+       /**
+        * If 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 ((this.bits & IsReachableMASK) == 0) {
+//                     return;
+//             }
+//             int pc = codeStream.position;
+//             Label endifLabel = new Label(codeStream);
+//
+//             // optimizing the then/else part code gen
+//             Constant cst;
+//             boolean hasThenPart = 
+//                     !(((cst = this.condition.optimizedBooleanConstant()) != NotAConstant
+//                                     && cst.booleanValue() == false)
+//                             || this.thenStatement == null
+//                             || this.thenStatement.isEmptyBlock());
+//             boolean hasElsePart =
+//                     !((cst != NotAConstant && cst.booleanValue() == true)
+//                             || this.elseStatement == null
+//                             || this.elseStatement.isEmptyBlock());
+//
+//             if (hasThenPart) {
+//                     Label falseLabel;
+//                     // generate boolean condition
+//                     this.condition.generateOptimizedBoolean(
+//                             currentScope,
+//                             codeStream,
+//                             null,
+//                             (falseLabel = new Label(codeStream)),
+//                             true);
+//                     // May loose some local variable initializations : affecting the local variable attributes
+//                     if (thenInitStateIndex != -1) {
+//                             codeStream.removeNotDefinitelyAssignedVariables(
+//                                     currentScope,
+//                                     thenInitStateIndex);
+//                             codeStream.addDefinitelyAssignedVariables(currentScope, thenInitStateIndex);
+//                     }
+//                     // generate then statement
+//                     this.thenStatement.generateCode(currentScope, codeStream);
+//                     // jump around the else statement
+//                     if (hasElsePart && !thenExit) {
+//                             this.thenStatement.branchChainTo(endifLabel);
+//                             int position = codeStream.position;
+//                             codeStream.goto_(endifLabel);
+//                             codeStream.updateLastRecordedEndPC(position);
+//                             //goto is tagged as part of the thenAction block
+//                     }
+//                     falseLabel.place();
+//             } else {
+//                     if (hasElsePart) {
+//                             // generate boolean condition
+//                             this.condition.generateOptimizedBoolean(
+//                                     currentScope,
+//                                     codeStream,
+//                                     endifLabel,
+//                                     null,
+//                                     true);
+//                     } else {
+//                             // generate condition side-effects
+//                             this.condition.generateCode(currentScope, codeStream, false);
+//                             codeStream.recordPositionsFrom(pc, this.sourceStart);
+//                     }
+//             }
+//             // generate else statement
+//             if (hasElsePart) {
+//                     // May loose some local variable initializations : affecting the local variable attributes
+//                     if (elseInitStateIndex != -1) {
+//                             codeStream.removeNotDefinitelyAssignedVariables(
+//                                     currentScope,
+//                                     elseInitStateIndex);
+//                             codeStream.addDefinitelyAssignedVariables(currentScope, elseInitStateIndex);
+//                     }
+//                     this.elseStatement.generateCode(currentScope, codeStream);
+//             }
+//             endifLabel.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 StringBuffer printStatement(int indent, StringBuffer output) {
+
+               printIndent(indent, output).append("if ("); //$NON-NLS-1$
+               condition.printExpression(0, output).append(")\n");     //$NON-NLS-1$ 
+               thenStatement.printStatement(indent + 2, output);
+               if (elseStatement != null) {
+                       output.append('\n');
+                       printIndent(indent, output);
+                       output.append("else\n"); //$NON-NLS-1$
+                       elseStatement.printStatement(indent + 2, output);
+               }
+               return output;
+       }
+       public void resolve(BlockScope scope) {
+
+               TypeBinding type = condition.resolveTypeExpecting(scope, BooleanBinding);
+               condition.implicitWidening(type, type);
+               if (thenStatement != null)
+                       thenStatement.resolve(scope);
+               if (elseStatement != null)
+                       elseStatement.resolve(scope);
+       }
+
+       public String toString(int tab) {
+
+               String inFront, s = tabString(tab);
+               inFront = s;
+               s = s + "if (" + condition.toStringExpression() + ") \n";       //$NON-NLS-1$ //$NON-NLS-2$
+               s = s + thenStatement.toString(tab + 2) + ";"; //$NON-NLS-1$
+               if (elseStatement != null)
+                       s = s + "\n" + inFront + "else\n" + elseStatement.toString(tab + 2) + ";"; //$NON-NLS-2$ //$NON-NLS-1$ //$NON-NLS-3$
+               return s;
+       }
+
+       public void traverse(
+           ASTVisitor visitor,
+               BlockScope blockScope) {
 
-  public Expression condition;
-  public ElseIf[] elseifs;
-  public Else els;
-
-  public IfStatement(Expression condition,
-                     ElseIf[] elseifs,
-                     Else els,
-                     int sourceStart,
-                     int sourceEnd) {
-    super(sourceStart, sourceEnd);
-    this.condition = condition;
-    this.elseifs = elseifs;
-    this.els = els;
-  }
-
-  /**
-   * Return the object into String.
-   * @param tab how many tabs (not used here
-   * @return a String
-   */
-  public String toString(int tab) {
-    final StringBuffer buff = new StringBuffer(tabString(tab));
-    buff.append("if (");
-    buff.append(condition.toStringExpression()).append(") ");
-    for (int i = 0; i < elseifs.length; i++) {
-      ElseIf elseif = elseifs[i];
-      buff.append(elseif.toString(tab+1));
-      buff.append('\n');
-    }
-    if (els != null) {
-      buff.append(els.toString(tab+1));
-      buff.append('\n');
-    }
-    return buff.toString();
-  }
+               if (visitor.visit(this, blockScope)) {
+                       condition.traverse(visitor, blockScope);
+                       if (thenStatement != null)
+                               thenStatement.traverse(visitor, blockScope);
+                       if (elseStatement != null)
+                               elseStatement.traverse(visitor, blockScope);
+               }
+               visitor.endVisit(this, blockScope);
+       }
 }