| /******************************************************************************* |
| * 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 org.eclipse.jdt.internal.compiler.ast; |
| |
| import org.eclipse.jdt.internal.compiler.IAbstractSyntaxTreeVisitor; |
| import org.eclipse.jdt.internal.compiler.impl.*; |
| import org.eclipse.jdt.internal.compiler.codegen.*; |
| import org.eclipse.jdt.internal.compiler.flow.*; |
| import org.eclipse.jdt.internal.compiler.lookup.*; |
| |
| public class DoStatement extends Statement { |
| |
| public Expression condition; |
| public Statement action; |
| |
| private Label breakLabel, continueLabel; |
| |
| // for local variables table attributes |
| int mergedInitStateIndex = -1; |
| |
| public DoStatement(Expression condition, Statement action, int s, int e) { |
| |
| this.sourceStart = s; |
| this.sourceEnd = e; |
| this.condition = condition; |
| this.action = action; |
| } |
| |
| public FlowInfo analyseCode( |
| BlockScope currentScope, |
| FlowContext flowContext, |
| FlowInfo flowInfo) { |
| |
| breakLabel = new Label(); |
| continueLabel = new Label(); |
| LoopingFlowContext loopingContext = |
| new LoopingFlowContext( |
| flowContext, |
| this, |
| breakLabel, |
| continueLabel, |
| currentScope); |
| |
| Constant cst = condition.constant; |
| boolean isConditionTrue = cst != NotAConstant && cst.booleanValue() == true; |
| cst = condition.optimizedBooleanConstant(); |
| boolean isConditionOptimizedTrue = cst != NotAConstant && cst.booleanValue() == true; |
| boolean isConditionOptimizedFalse = cst != NotAConstant && cst.booleanValue() == false; |
| |
| int previousMode = flowInfo.reachMode(); |
| |
| if ((action != null) && !action.isEmptyBlock()) { |
| flowInfo = action.analyseCode(currentScope, loopingContext, flowInfo); |
| |
| // code generation can be optimized when no need to continue in the loop |
| if (!flowInfo.isReachable() && !loopingContext.initsOnContinue.isReachable()) { |
| continueLabel = null; |
| } |
| } |
| /* Reset reach mode, to address following scenario. |
| * final blank; |
| * do { if (true) break; else blank = 0; } while(false); |
| * blank = 1; // may be initialized already |
| */ |
| flowInfo.setReachMode(previousMode); |
| |
| flowInfo = |
| condition.analyseCode( |
| currentScope, |
| loopingContext, |
| (action == null |
| ? flowInfo |
| : (flowInfo.mergedWith(loopingContext.initsOnContinue)))); |
| if (!isConditionOptimizedFalse && continueLabel != null) { |
| loopingContext.complainOnFinalAssignmentsInLoop(currentScope, flowInfo); |
| } |
| |
| // infinite loop |
| FlowInfo mergedInfo; |
| if (isConditionTrue) { |
| mergedInfo = loopingContext.initsOnBreak; |
| if (!mergedInfo.isReachable()) mergedInfo.addPotentialInitializationsFrom(flowInfo.initsWhenFalse()); |
| } else { |
| // end of loop: either condition false or break |
| mergedInfo = |
| flowInfo.initsWhenFalse().unconditionalInits().mergedWith( |
| loopingContext.initsOnBreak); |
| if (isConditionOptimizedTrue && !loopingContext.initsOnBreak.isReachable()) { |
| mergedInfo.setReachMode(FlowInfo.UNREACHABLE); |
| } |
| } |
| mergedInitStateIndex = |
| currentScope.methodScope().recordInitializationStates(mergedInfo); |
| return mergedInfo; |
| } |
| |
| /** |
| * Do statement code generation |
| * |
| */ |
| public void generateCode(BlockScope currentScope, CodeStream codeStream) { |
| |
| if ((bits & IsReachableMASK) == 0) { |
| return; |
| } |
| int pc = codeStream.position; |
| |
| // labels management |
| Label actionLabel = new Label(codeStream); |
| actionLabel.place(); |
| breakLabel.codeStream = codeStream; |
| if (continueLabel != null) { |
| continueLabel.codeStream = codeStream; |
| } |
| |
| // generate action |
| if (action != null) { |
| action.generateCode(currentScope, codeStream); |
| } |
| // generate condition |
| 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 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 inFront, s = tabString(tab); |
| inFront = s; |
| s = s + "do"; //$NON-NLS-1$ |
| if (action == null) |
| s = s + " {}\n"; //$NON-NLS-1$ |
| else if (action instanceof Block) |
| s = s + "\n" + action.toString(tab + 1) + "\n"; //$NON-NLS-2$ //$NON-NLS-1$ |
| else |
| s = s + " {\n" + action.toString(tab + 1) + ";}\n"; //$NON-NLS-1$ //$NON-NLS-2$ |
| s = s + inFront + "while (" + condition.toStringExpression() + ")"; //$NON-NLS-1$ //$NON-NLS-2$ |
| return s; |
| } |
| |
| public void traverse(IAbstractSyntaxTreeVisitor visitor, BlockScope scope) { |
| |
| if (visitor.visit(this, scope)) { |
| if (action != null) { |
| action.traverse(visitor, scope); |
| } |
| condition.traverse(visitor, scope); |
| } |
| visitor.endVisit(this, scope); |
| } |
| } |