Refactory: removed unnecessary local variables and imports.
[phpeclipse.git] / net.sourceforge.phpeclipse / src / net / sourceforge / phpdt / internal / compiler / ast / WhileStatement.java
index 80ff26a..ec7dd3e 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 java.util.List;
-import java.util.ArrayList;
+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;
 
-/**
- * A While statement.
- * @author Matthieu Casanova
- */
 public class WhileStatement extends Statement {
 
-  /** 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(final Expression condition,
-                        final Statement action,
-                        final int sourceStart,
-                        final 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(final int tab) {
-    final String s = tabString(tab);
-    final StringBuffer buff = new StringBuffer(s).append("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();
-  }
-
-  /**
-   * Get the variables from outside (parameters, globals ...)
-   */
-  public void getOutsideVariable(final List list) {
-    condition.getOutsideVariable(list); // todo: check if unuseful
-    if (action != null) {
-      action.getOutsideVariable(list);
-    }
-  }
-
-  /**
-   * get the modified variables.
-   */
-  public void getModifiedVariable(final List list) {
-    condition.getModifiedVariable(list);
-    if (action != null) {
-      action.getModifiedVariable(list);
-    }
-  }
-
-  /**
-   * Get the variables used.
-   */
-  public void getUsedVariable(final List list) {
-    condition.getUsedVariable(list);
-    if (action != null) {
-      action.getUsedVariable(list);
-    }
-  }
+       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) {
+
+               if (visitor.visit(this, blockScope)) {
+                       condition.traverse(visitor, blockScope);
+                       if (action != null)
+                               action.traverse(visitor, blockScope);
+               }
+               visitor.endVisit(this, blockScope);
+       }
 }