| /******************************************************************************* |
| * 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.classfmt.ClassFileConstants; |
| import org.eclipse.jdt.internal.compiler.codegen.*; |
| import org.eclipse.jdt.internal.compiler.flow.*; |
| import org.eclipse.jdt.internal.compiler.impl.Constant; |
| import org.eclipse.jdt.internal.compiler.lookup.*; |
| |
| public class ForStatement extends Statement { |
| |
| public Statement[] initializations; |
| public Expression condition; |
| public Statement[] increments; |
| public Statement action; |
| |
| //when there is no local declaration, there is no need of a new scope |
| //scope is positionned either to a new scope, or to the "upper"scope (see resolveType) |
| public boolean neededScope; |
| public BlockScope scope; |
| |
| private Label breakLabel, continueLabel; |
| |
| // for local variables table attributes |
| int preCondInitStateIndex = -1; |
| int condIfTrueInitStateIndex = -1; |
| int mergedInitStateIndex = -1; |
| |
| public ForStatement( |
| Statement[] initializations, |
| Expression condition, |
| Statement[] increments, |
| Statement action, |
| boolean neededScope, |
| int s, |
| int e) { |
| |
| this.sourceStart = s; |
| this.sourceEnd = e; |
| this.initializations = initializations; |
| this.condition = condition; |
| this.increments = increments; |
| this.action = action; |
| // remember useful empty statement |
| if (action instanceof EmptyStatement) action.bits |= IsUsefulEmptyStatementMASK; |
| this.neededScope = neededScope; |
| } |
| |
| public FlowInfo analyseCode( |
| BlockScope currentScope, |
| FlowContext flowContext, |
| FlowInfo flowInfo) { |
| |
| breakLabel = new Label(); |
| continueLabel = new Label(); |
| |
| // process the initializations |
| if (initializations != null) { |
| for (int i = 0, count = initializations.length; i < count; i++) { |
| flowInfo = initializations[i].analyseCode(scope, flowContext, flowInfo); |
| } |
| } |
| preCondInitStateIndex = |
| currentScope.methodScope().recordInitializationStates(flowInfo); |
| |
| Constant cst = this.condition == null ? null : this.condition.constant; |
| boolean isConditionTrue = cst == null || (cst != NotAConstant && cst.booleanValue() == true); |
| boolean isConditionFalse = cst != null && (cst != NotAConstant && cst.booleanValue() == false); |
| |
| cst = this.condition == null ? null : this.condition.optimizedBooleanConstant(); |
| boolean isConditionOptimizedTrue = cst == null || (cst != NotAConstant && cst.booleanValue() == true); |
| boolean isConditionOptimizedFalse = cst != null && (cst != NotAConstant && cst.booleanValue() == false); |
| |
| // process the condition |
| LoopingFlowContext condLoopContext = null; |
| FlowInfo condInfo = flowInfo.copy().unconditionalInits().discardNullRelatedInitializations(); |
| if (condition != null) { |
| if (!isConditionTrue) { |
| condInfo = |
| condition.analyseCode( |
| scope, |
| (condLoopContext = |
| new LoopingFlowContext(flowContext, this, null, null, scope)), |
| condInfo); |
| } |
| } |
| |
| // process the action |
| LoopingFlowContext loopingContext; |
| FlowInfo actionInfo; |
| if (action == null |
| || (action.isEmptyBlock() && currentScope.environment().options.complianceLevel <= ClassFileConstants.JDK1_3)) { |
| if (condLoopContext != null) |
| condLoopContext.complainOnDeferredChecks(scope, condInfo); |
| if (isConditionTrue) { |
| return FlowInfo.DEAD_END; |
| } else { |
| if (isConditionFalse){ |
| continueLabel = null; // for(;false;p()); |
| } |
| actionInfo = condInfo.initsWhenTrue().copy().unconditionalInits().discardNullRelatedInitializations(); |
| loopingContext = |
| new LoopingFlowContext(flowContext, this, breakLabel, continueLabel, scope); |
| } |
| } else { |
| loopingContext = |
| new LoopingFlowContext(flowContext, this, breakLabel, continueLabel, scope); |
| FlowInfo initsWhenTrue = condInfo.initsWhenTrue(); |
| condIfTrueInitStateIndex = |
| currentScope.methodScope().recordInitializationStates(initsWhenTrue); |
| |
| if (isConditionFalse) { |
| actionInfo = FlowInfo.DEAD_END; |
| } else { |
| actionInfo = initsWhenTrue.copy().unconditionalInits().discardNullRelatedInitializations(); |
| if (isConditionOptimizedFalse){ |
| actionInfo.setReachMode(FlowInfo.UNREACHABLE); |
| } |
| } |
| if (!this.action.complainIfUnreachable(actionInfo, scope, false)) { |
| actionInfo = action.analyseCode(scope, loopingContext, actionInfo); |
| } |
| |
| // code generation can be optimized when no need to continue in the loop |
| if (!actionInfo.isReachable() && !loopingContext.initsOnContinue.isReachable()) { |
| continueLabel = null; |
| } else { |
| if (condLoopContext != null) |
| condLoopContext.complainOnDeferredChecks(scope, condInfo); |
| actionInfo = actionInfo.mergedWith(loopingContext.initsOnContinue.unconditionalInits()); |
| loopingContext.complainOnDeferredChecks(scope, actionInfo); |
| } |
| } |
| // for increments |
| FlowInfo exitBranch = condInfo.initsWhenFalse(); |
| exitBranch.addInitializationsFrom(flowInfo); // recover null inits from before condition analysis |
| if (continueLabel != null) { |
| if (increments != null) { |
| LoopingFlowContext loopContext = |
| new LoopingFlowContext(flowContext, this, null, null, scope); |
| for (int i = 0, count = increments.length; i < count; i++) { |
| actionInfo = increments[i].analyseCode(scope, loopContext, actionInfo); |
| } |
| loopContext.complainOnDeferredChecks(scope, actionInfo); |
| } |
| exitBranch.addPotentialInitializationsFrom(actionInfo.unconditionalInits()); |
| } |
| |
| //end of loop |
| FlowInfo mergedInfo = FlowInfo.mergedOptimizedBranches( |
| loopingContext.initsOnBreak, |
| isConditionOptimizedTrue, |
| exitBranch, |
| isConditionOptimizedFalse, |
| !isConditionTrue /*for(;;){}while(true); unreachable(); */); |
| mergedInitStateIndex = currentScope.methodScope().recordInitializationStates(mergedInfo); |
| return mergedInfo; |
| } |
| |
| /** |
| * For statement code generation |
| * |
| * @param currentScope org.eclipse.jdt.internal.compiler.lookup.BlockScope |
| * @param codeStream org.eclipse.jdt.internal.compiler.codegen.CodeStream |
| */ |
| public void generateCode(BlockScope currentScope, CodeStream codeStream) { |
| |
| if ((bits & IsReachableMASK) == 0) { |
| return; |
| } |
| int pc = codeStream.position; |
| |
| // generate the initializations |
| if (initializations != null) { |
| for (int i = 0, max = initializations.length; i < max; i++) { |
| initializations[i].generateCode(scope, codeStream); |
| } |
| } |
| |
| // label management |
| Label actionLabel = new Label(codeStream); |
| Label conditionLabel = new Label(codeStream); |
| breakLabel.initialize(codeStream); |
| if (continueLabel != null) { |
| continueLabel.initialize(codeStream); |
| } |
| // jump over the actionBlock |
| if ((condition != null) |
| && (condition.constant == NotAConstant) |
| && !((action == null || action.isEmptyBlock()) && (increments == null))) { |
| int jumpPC = codeStream.position; |
| codeStream.goto_(conditionLabel); |
| codeStream.recordPositionsFrom(jumpPC, condition.sourceStart); |
| } |
| // generate the loop action |
| actionLabel.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(scope, codeStream); |
| } |
| // continuation point |
| if (continueLabel != null) { |
| continueLabel.place(); |
| // generate the increments for next iteration |
| if (increments != null) { |
| for (int i = 0, max = increments.length; i < max; i++) { |
| increments[i].generateCode(scope, codeStream); |
| } |
| } |
| } |
| |
| // May loose some local variable initializations : affecting the local variable attributes |
| if (preCondInitStateIndex != -1) { |
| codeStream.removeNotDefinitelyAssignedVariables(currentScope, preCondInitStateIndex); |
| } |
| |
| // generate the condition |
| conditionLabel.place(); |
| if ((condition != null) && (condition.constant == NotAConstant)) { |
| condition.generateOptimizedBoolean(scope, codeStream, actionLabel, null, true); |
| } else { |
| if (continueLabel != null) { |
| codeStream.goto_(actionLabel); |
| } |
| } |
| breakLabel.place(); |
| |
| // May loose some local variable initializations : affecting the local variable attributes |
| if (neededScope) { |
| codeStream.exitUserScope(scope); |
| } |
| if (mergedInitStateIndex != -1) { |
| codeStream.removeNotDefinitelyAssignedVariables(currentScope, mergedInitStateIndex); |
| codeStream.addDefinitelyAssignedVariables(currentScope, mergedInitStateIndex); |
| } |
| codeStream.recordPositionsFrom(pc, this.sourceStart); |
| } |
| |
| public StringBuffer printStatement(int tab, StringBuffer output) { |
| |
| printIndent(tab, output).append("for ("); //$NON-NLS-1$ |
| //inits |
| if (initializations != null) { |
| for (int i = 0; i < initializations.length; i++) { |
| //nice only with expressions |
| if (i > 0) output.append(", "); //$NON-NLS-1$ |
| initializations[i].print(0, output); |
| } |
| } |
| output.append("; "); //$NON-NLS-1$ |
| //cond |
| if (condition != null) condition.printExpression(0, output); |
| output.append("; "); //$NON-NLS-1$ |
| //updates |
| if (increments != null) { |
| for (int i = 0; i < increments.length; i++) { |
| if (i > 0) output.append(", "); //$NON-NLS-1$ |
| increments[i].print(0, output); |
| } |
| } |
| output.append(") "); //$NON-NLS-1$ |
| //block |
| if (action == null) |
| output.append(';'); |
| else { |
| output.append('\n'); |
| action.printStatement(tab + 1, output); //$NON-NLS-1$ |
| } |
| return output.append(';'); |
| } |
| |
| public void resolve(BlockScope upperScope) { |
| |
| // use the scope that will hold the init declarations |
| scope = neededScope ? new BlockScope(upperScope) : upperScope; |
| if (initializations != null) |
| for (int i = 0, length = initializations.length; i < length; i++) |
| initializations[i].resolve(scope); |
| if (condition != null) { |
| TypeBinding type = condition.resolveTypeExpecting(scope, BooleanBinding); |
| condition.computeConversion(scope, type, type); |
| } |
| if (increments != null) |
| for (int i = 0, length = increments.length; i < length; i++) |
| increments[i].resolve(scope); |
| if (action != null) |
| action.resolve(scope); |
| } |
| |
| public void traverse( |
| ASTVisitor visitor, |
| BlockScope blockScope) { |
| |
| if (visitor.visit(this, blockScope)) { |
| if (initializations != null) { |
| int initializationsLength = initializations.length; |
| for (int i = 0; i < initializationsLength; i++) |
| initializations[i].traverse(visitor, scope); |
| } |
| |
| if (condition != null) |
| condition.traverse(visitor, scope); |
| |
| if (increments != null) { |
| int incrementsLength = increments.length; |
| for (int i = 0; i < incrementsLength; i++) |
| increments[i].traverse(visitor, scope); |
| } |
| |
| if (action != null) |
| action.traverse(visitor, scope); |
| } |
| visitor.endVisit(this, blockScope); |
| } |
| } |
