| /******************************************************************************* |
| * Copyright (c) 2000, 2018 IBM Corporation and others. |
| * |
| * This program and the accompanying materials |
| * are made available under the terms of the Eclipse Public License 2.0 |
| * which accompanies this distribution, and is available at |
| * https://www.eclipse.org/legal/epl-2.0/ |
| * |
| * SPDX-License-Identifier: EPL-2.0 |
| * |
| * 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.codegen.*; |
| import org.eclipse.jdt.internal.compiler.flow.*; |
| import org.eclipse.jdt.internal.compiler.lookup.*; |
| |
| public class LabeledStatement extends Statement { |
| |
| public Statement statement; |
| public char[] label; |
| public BranchLabel targetLabel; |
| public int labelEnd; |
| |
| // for local variables table attributes |
| int mergedInitStateIndex = -1; |
| |
| /** |
| * LabeledStatement constructor comment. |
| */ |
| public LabeledStatement(char[] label, Statement statement, long labelPosition, int sourceEnd) { |
| |
| this.statement = statement; |
| // remember useful empty statement |
| if (statement instanceof EmptyStatement) statement.bits |= IsUsefulEmptyStatement; |
| this.label = label; |
| this.sourceStart = (int)(labelPosition >>> 32); |
| this.labelEnd = (int) labelPosition; |
| this.sourceEnd = sourceEnd; |
| } |
| |
| @Override |
| public FlowInfo analyseCode( |
| BlockScope currentScope, |
| FlowContext flowContext, |
| FlowInfo flowInfo) { |
| |
| // need to stack a context to store explicit label, answer inits in case of normal completion merged |
| // with those relative to the exit path from break statement occurring inside the labeled statement. |
| if (this.statement == null) { |
| return flowInfo; |
| } else { |
| LabelFlowContext labelContext; |
| FlowInfo statementInfo, mergedInfo; |
| statementInfo = this.statement.analyseCode( |
| currentScope, |
| (labelContext = |
| new LabelFlowContext( |
| flowContext, |
| this, |
| this.label, |
| (this.targetLabel = new BranchLabel()), |
| currentScope)), |
| flowInfo); |
| boolean reinjectNullInfo = (statementInfo.tagBits & FlowInfo.UNREACHABLE) != 0 && |
| (labelContext.initsOnBreak.tagBits & FlowInfo.UNREACHABLE) == 0; |
| mergedInfo = statementInfo.mergedWith(labelContext.initsOnBreak); |
| if (reinjectNullInfo) { |
| // an embedded loop has had no chance to reinject forgotten null info |
| ((UnconditionalFlowInfo)mergedInfo).addNullInfoFrom(flowInfo.unconditionalFieldLessCopy()). |
| addNullInfoFrom(labelContext.initsOnBreak.unconditionalFieldLessCopy()); |
| } |
| this.mergedInitStateIndex = |
| currentScope.methodScope().recordInitializationStates(mergedInfo); |
| if ((this.bits & ASTNode.LabelUsed) == 0) { |
| currentScope.problemReporter().unusedLabel(this); |
| } |
| return mergedInfo; |
| } |
| } |
| |
| @Override |
| public ASTNode concreteStatement() { |
| |
| // return statement.concreteStatement(); // for supporting nested labels: a:b:c: someStatement (see 21912) |
| return this.statement; |
| } |
| |
| /** |
| * Code generation for labeled statement |
| * |
| * may not need actual source positions recording |
| * |
| * @param currentScope org.eclipse.jdt.internal.compiler.lookup.BlockScope |
| * @param codeStream org.eclipse.jdt.internal.compiler.codegen.CodeStream |
| */ |
| @Override |
| public void generateCode(BlockScope currentScope, CodeStream codeStream) { |
| |
| if ((this.bits & IsReachable) == 0) { |
| return; |
| } |
| int pc = codeStream.position; |
| if (this.targetLabel != null) { |
| this.targetLabel.initialize(codeStream); |
| if (this.statement != null) { |
| this.statement.generateCode(currentScope, codeStream); |
| } |
| this.targetLabel.place(); |
| } |
| // May loose some local variable initializations : affecting the local variable attributes |
| if (this.mergedInitStateIndex != -1) { |
| codeStream.removeNotDefinitelyAssignedVariables(currentScope, this.mergedInitStateIndex); |
| codeStream.addDefinitelyAssignedVariables(currentScope, this.mergedInitStateIndex); |
| } |
| codeStream.recordPositionsFrom(pc, this.sourceStart); |
| } |
| |
| @Override |
| public StringBuffer printStatement(int tab, StringBuffer output) { |
| |
| printIndent(tab, output).append(this.label).append(": "); //$NON-NLS-1$ |
| if (this.statement == null) |
| output.append(';'); |
| else |
| this.statement.printStatement(0, output); |
| return output; |
| } |
| |
| @Override |
| public void resolve(BlockScope scope) { |
| |
| if (this.statement != null) { |
| this.statement.resolve(scope); |
| } |
| } |
| |
| |
| @Override |
| public void traverse( |
| ASTVisitor visitor, |
| BlockScope blockScope) { |
| |
| if (visitor.visit(this, blockScope)) { |
| if (this.statement != null) this.statement.traverse(visitor, blockScope); |
| } |
| visitor.endVisit(this, blockScope); |
| } |
| |
| @Override |
| public boolean doesNotCompleteNormally() { |
| if (this.statement.breaksOut(this.label)) |
| return false; |
| return this.statement.doesNotCompleteNormally(); |
| } |
| |
| @Override |
| public boolean completesByContinue() { |
| return this.statement instanceof ContinueStatement; // NOT this.statement.continuesAtOuterLabel |
| } |
| } |