| /******************************************************************************* |
| * Copyright (c) 2000, 2004 IBM Corporation and others. |
| * All rights reserved. This program and the accompanying materials |
| * are made available under the terms of the Eclipse Public License v1.0 |
| * which accompanies this distribution, and is available at |
| * http://www.eclipse.org/legal/epl-v10.html |
| * |
| * Contributors: |
| * IBM Corporation - initial API and implementation |
| *******************************************************************************/ |
| package org.eclipse.jdt.internal.compiler.ast; |
| |
| import org.eclipse.jdt.internal.compiler.ASTVisitor; |
| 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; |
| // remember useful empty statement |
| if (action instanceof EmptyStatement) action.bits |= IsUsefulEmptyStatementMASK; |
| } |
| |
| 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(); |
| |
| FlowInfo actionInfo = flowInfo.copy().unconditionalInits().discardNullRelatedInitializations(); |
| if ((action != null) && !action.isEmptyBlock()) { |
| 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; |
| } |
| } |
| /* Reset reach mode, to address following scenario. |
| * final blank; |
| * do { if (true) break; else blank = 0; } while(false); |
| * blank = 1; // may be initialized already |
| */ |
| actionInfo.setReachMode(previousMode); |
| |
| actionInfo = |
| condition.analyseCode( |
| currentScope, |
| loopingContext, |
| (action == null |
| ? actionInfo |
| : (actionInfo.mergedWith(loopingContext.initsOnContinue)))); |
| if (!isConditionOptimizedFalse && continueLabel != null) { |
| loopingContext.complainOnDeferredChecks(currentScope, actionInfo); |
| } |
| |
| // end of loop |
| FlowInfo mergedInfo = FlowInfo.mergedOptimizedBranches( |
| loopingContext.initsOnBreak, |
| isConditionOptimizedTrue, |
| actionInfo.initsWhenFalse().addInitializationsFrom(flowInfo), // recover null inits from before condition analysis |
| false, // never consider opt false case for DO loop, since break can always occur (47776) |
| !isConditionTrue /*do{}while(true); 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.initialize(codeStream); |
| if (continueLabel != null) { |
| continueLabel.initialize(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.addDefinitelyAssignedVariables(currentScope, mergedInitStateIndex); |
| } |
| codeStream.recordPositionsFrom(pc, this.sourceStart); |
| |
| } |
| |
| public StringBuffer printStatement(int indent, StringBuffer output) { |
| |
| printIndent(indent, output).append("do"); //$NON-NLS-1$ |
| if (action == null) |
| output.append(" ;\n"); //$NON-NLS-1$ |
| else { |
| output.append('\n'); |
| action.printStatement(indent + 1, output).append('\n'); |
| } |
| output.append("while ("); //$NON-NLS-1$ |
| return condition.printExpression(0, output).append(");"); //$NON-NLS-1$ |
| } |
| public void resolve(BlockScope scope) { |
| |
| TypeBinding type = condition.resolveTypeExpecting(scope, BooleanBinding); |
| condition.computeConversion(scope, type, type); |
| if (action != null) |
| action.resolve(scope); |
| } |
| |
| public void traverse(ASTVisitor visitor, BlockScope scope) { |
| |
| if (visitor.visit(this, scope)) { |
| if (action != null) { |
| action.traverse(visitor, scope); |
| } |
| condition.traverse(visitor, scope); |
| } |
| visitor.endVisit(this, scope); |
| } |
| } |