| /******************************************************************************* |
| * Copyright (c) 2000, 2014 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 |
| * Technical University Berlin - extended API and implementation |
| * Stephan Herrmann - Contributions for |
| * bug 319201 - [null] no warning when unboxing SingleNameReference causes NPE |
| * bug 349326 - [1.7] new warning for missing try-with-resources |
| * bug 345305 - [compiler][null] Compiler misidentifies a case of "variable can only be null" |
| * bug 403147 - [compiler][null] FUP of bug 400761: consolidate interaction between unboxing, NPE, and deferred checking |
| * Bug 415790 - [compiler][resource]Incorrect potential resource leak warning in for loop with close in try/catch |
| *******************************************************************************/ |
| 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 positioned either to a new scope, or to the "upper"scope (see resolveType) |
| public BlockScope scope; |
| |
| private BranchLabel breakLabel, continueLabel; |
| |
| // for local variables table attributes |
| int preCondInitStateIndex = -1; |
| int preIncrementsInitStateIndex = -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 |= ASTNode.IsUsefulEmptyStatement; |
| if (neededScope) { |
| this.bits |= ASTNode.NeededScope; |
| } |
| } |
| |
| @Override |
| public FlowInfo analyseCode(BlockScope currentScope, FlowContext flowContext, FlowInfo flowInfo) { |
| this.breakLabel = new BranchLabel(); |
| this.continueLabel = new BranchLabel(); |
| int initialComplaintLevel = (flowInfo.reachMode() & FlowInfo.UNREACHABLE) != 0 ? Statement.COMPLAINED_FAKE_REACHABLE : Statement.NOT_COMPLAINED; |
| |
| // process the initializations |
| if (this.initializations != null) { |
| for (int i = 0, count = this.initializations.length; i < count; i++) { |
| flowInfo = this.initializations[i].analyseCode(this.scope, flowContext, flowInfo); |
| } |
| } |
| this.preCondInitStateIndex = |
| currentScope.methodScope().recordInitializationStates(flowInfo); |
| |
| Constant cst = this.condition == null ? null : this.condition.constant; |
| boolean isConditionTrue = cst == null || (cst != Constant.NotAConstant && cst.booleanValue() == true); |
| boolean isConditionFalse = cst != null && (cst != Constant.NotAConstant && cst.booleanValue() == false); |
| |
| cst = this.condition == null ? null : this.condition.optimizedBooleanConstant(); |
| boolean isConditionOptimizedTrue = cst == null || (cst != Constant.NotAConstant && cst.booleanValue() == true); |
| boolean isConditionOptimizedFalse = cst != null && (cst != Constant.NotAConstant && cst.booleanValue() == false); |
| |
| // process the condition |
| LoopingFlowContext condLoopContext = null; |
| FlowInfo condInfo = flowInfo.nullInfoLessUnconditionalCopy(); |
| if (this.condition != null) { |
| if (!isConditionTrue) { |
| condInfo = |
| this.condition.analyseCode( |
| this.scope, |
| (condLoopContext = |
| new LoopingFlowContext(flowContext, flowInfo, this, null, |
| null, this.scope, true)), |
| condInfo); |
| this.condition.checkNPEbyUnboxing(currentScope, flowContext, flowInfo); |
| } |
| } |
| |
| // process the action |
| LoopingFlowContext loopingContext; |
| UnconditionalFlowInfo actionInfo; |
| if (this.action == null |
| || (this.action.isEmptyBlock() && currentScope.compilerOptions().complianceLevel <= ClassFileConstants.JDK1_3)) { |
| if (condLoopContext != null) |
| condLoopContext.complainOnDeferredFinalChecks(this.scope, condInfo); |
| if (isConditionTrue) { |
| if (condLoopContext != null) { |
| condLoopContext.complainOnDeferredNullChecks(currentScope, |
| condInfo); |
| } |
| return FlowInfo.DEAD_END; |
| } else { |
| if (isConditionFalse){ |
| this.continueLabel = null; // for(;false;p()); |
| } |
| actionInfo = condInfo.initsWhenTrue().unconditionalCopy(); |
| loopingContext = |
| new LoopingFlowContext(flowContext, flowInfo, this, |
| this.breakLabel, this.continueLabel, this.scope, false); |
| // there is no action guarded by a preTest, so we use preTest=false |
| // to avoid pointless burdens of updating FlowContext.conditionalLevel |
| } |
| } |
| else { |
| loopingContext = |
| new LoopingFlowContext(flowContext, flowInfo, this, this.breakLabel, |
| this.continueLabel, this.scope, true); |
| FlowInfo initsWhenTrue = condInfo.initsWhenTrue(); |
| this.condIfTrueInitStateIndex = |
| currentScope.methodScope().recordInitializationStates(initsWhenTrue); |
| |
| if (isConditionFalse) { |
| actionInfo = FlowInfo.DEAD_END; |
| } else { |
| actionInfo = initsWhenTrue.unconditionalCopy(); |
| if (isConditionOptimizedFalse){ |
| actionInfo.setReachMode(FlowInfo.UNREACHABLE_OR_DEAD); |
| } |
| } |
| if (this.action.complainIfUnreachable(actionInfo, this.scope, initialComplaintLevel, true) < Statement.COMPLAINED_UNREACHABLE) { |
| actionInfo = this.action.analyseCode(this.scope, loopingContext, actionInfo).unconditionalInits(); |
| } |
| |
| // code generation can be optimized when no need to continue in the loop |
| if ((actionInfo.tagBits & |
| loopingContext.initsOnContinue.tagBits & |
| FlowInfo.UNREACHABLE_OR_DEAD) != 0) { |
| this.continueLabel = null; |
| } |
| else { |
| if (condLoopContext != null) { |
| condLoopContext.complainOnDeferredFinalChecks(this.scope, |
| condInfo); |
| } |
| actionInfo = actionInfo.mergedWith(loopingContext.initsOnContinue); |
| loopingContext.complainOnDeferredFinalChecks(this.scope, |
| actionInfo); |
| } |
| } |
| // for increments |
| FlowInfo exitBranch = flowInfo.copy(); |
| // recover null inits from before condition analysis |
| LoopingFlowContext incrementContext = null; |
| if (this.continueLabel != null) { |
| if (this.increments != null) { |
| incrementContext = |
| new LoopingFlowContext(flowContext, flowInfo, this, null, |
| null, this.scope, true); |
| FlowInfo incrementInfo = actionInfo; |
| this.preIncrementsInitStateIndex = |
| currentScope.methodScope().recordInitializationStates(incrementInfo); |
| for (int i = 0, count = this.increments.length; i < count; i++) { |
| incrementInfo = this.increments[i]. |
| analyseCode(this.scope, incrementContext, incrementInfo); |
| } |
| incrementContext.complainOnDeferredFinalChecks(this.scope, |
| actionInfo = incrementInfo.unconditionalInits()); |
| } |
| exitBranch.addPotentialInitializationsFrom(actionInfo). |
| addInitializationsFrom(condInfo.initsWhenFalse()); |
| } else { |
| exitBranch.addInitializationsFrom(condInfo.initsWhenFalse()); |
| if (this.increments != null) { |
| if (initialComplaintLevel == Statement.NOT_COMPLAINED) { |
| currentScope.problemReporter().fakeReachable(this.increments[0]); |
| } |
| } |
| } |
| // nulls checks |
| if (condLoopContext != null) { |
| condLoopContext.complainOnDeferredNullChecks(currentScope, |
| actionInfo); |
| } |
| loopingContext.complainOnDeferredNullChecks(currentScope, |
| actionInfo); |
| if (incrementContext != null) { |
| incrementContext.complainOnDeferredNullChecks(currentScope, |
| actionInfo); |
| } |
| if (loopingContext.hasEscapingExceptions()) { // https://bugs.eclipse.org/bugs/show_bug.cgi?id=321926 |
| FlowInfo loopbackFlowInfo = flowInfo.copy(); |
| if (this.continueLabel != null) { // we do get to the bottom |
| // loopback | (loopback + action): |
| loopbackFlowInfo = loopbackFlowInfo.mergedWith(loopbackFlowInfo.unconditionalCopy().addNullInfoFrom(actionInfo).unconditionalInits()); |
| } |
| loopingContext.simulateThrowAfterLoopBack(loopbackFlowInfo); |
| } |
| //end of loop |
| FlowInfo mergedInfo = FlowInfo.mergedOptimizedBranches( |
| (loopingContext.initsOnBreak.tagBits & |
| FlowInfo.UNREACHABLE) != 0 ? |
| loopingContext.initsOnBreak : |
| flowInfo.addInitializationsFrom(loopingContext.initsOnBreak), // recover upstream null info |
| isConditionOptimizedTrue, |
| exitBranch, |
| isConditionOptimizedFalse, |
| !isConditionTrue /*for(;;){}while(true); unreachable(); */); |
| // Variables initialized only for the purpose of the for loop can be removed for further flow info |
| // https://bugs.eclipse.org/bugs/show_bug.cgi?id=359495 |
| if (this.initializations != null) { |
| for (int i = 0; i < this.initializations.length; i++) { |
| Statement init = this.initializations[i]; |
| if (init instanceof LocalDeclaration) { |
| LocalVariableBinding binding = ((LocalDeclaration) init).binding; |
| mergedInfo.resetAssignmentInfo(binding); |
| } |
| } |
| } |
| this.mergedInitStateIndex = currentScope.methodScope().recordInitializationStates(mergedInfo); |
| this.scope.checkUnclosedCloseables(mergedInfo, loopingContext, null, null); |
| return mergedInfo; |
| } |
| |
| /** |
| * For statement code generation |
| * |
| * @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; |
| |
| // generate the initializations |
| if (this.initializations != null) { |
| for (int i = 0, max = this.initializations.length; i < max; i++) { |
| this.initializations[i].generateCode(this.scope, codeStream); |
| } |
| } |
| Constant cst = this.condition == null ? null : this.condition.optimizedBooleanConstant(); |
| boolean isConditionOptimizedFalse = cst != null && (cst != Constant.NotAConstant && cst.booleanValue() == false); |
| if (isConditionOptimizedFalse) { |
| this.condition.generateCode(this.scope, codeStream, false); |
| // May loose some local variable initializations : affecting the local variable attributes |
| if ((this.bits & ASTNode.NeededScope) != 0) { |
| codeStream.exitUserScope(this.scope); |
| } |
| if (this.mergedInitStateIndex != -1) { |
| codeStream.removeNotDefinitelyAssignedVariables(currentScope, this.mergedInitStateIndex); |
| codeStream.addDefinitelyAssignedVariables(currentScope, this.mergedInitStateIndex); |
| } |
| codeStream.recordPositionsFrom(pc, this.sourceStart); |
| return; |
| } |
| |
| // label management |
| BranchLabel actionLabel = new BranchLabel(codeStream); |
| actionLabel.tagBits |= BranchLabel.USED; |
| BranchLabel conditionLabel = new BranchLabel(codeStream); |
| this.breakLabel.initialize(codeStream); |
| if (this.continueLabel == null) { |
| conditionLabel.place(); |
| if ((this.condition != null) && (this.condition.constant == Constant.NotAConstant)) { |
| this.condition.generateOptimizedBoolean(this.scope, codeStream, null, this.breakLabel, true); |
| } |
| } else { |
| this.continueLabel.initialize(codeStream); |
| // jump over the actionBlock |
| if ((this.condition != null) |
| && (this.condition.constant == Constant.NotAConstant) |
| && !((this.action == null || this.action.isEmptyBlock()) && (this.increments == null))) { |
| conditionLabel.tagBits |= BranchLabel.USED; |
| int jumpPC = codeStream.position; |
| codeStream.goto_(conditionLabel); |
| codeStream.recordPositionsFrom(jumpPC, this.condition.sourceStart); |
| } |
| } |
| |
| // generate the loop action |
| if (this.action != null) { |
| // Required to fix 1PR0XVS: LFRE:WINNT - Compiler: variable table for method appears incorrect |
| if (this.condIfTrueInitStateIndex != -1) { |
| // insert all locals initialized inside the condition into the action generated prior to the condition |
| codeStream.addDefinitelyAssignedVariables( |
| currentScope, |
| this.condIfTrueInitStateIndex); |
| } |
| actionLabel.place(); |
| this.action.generateCode(this.scope, codeStream); |
| } else { |
| actionLabel.place(); |
| } |
| if (this.preIncrementsInitStateIndex != -1) { |
| codeStream.removeNotDefinitelyAssignedVariables(currentScope, this.preIncrementsInitStateIndex); |
| codeStream.addDefinitelyAssignedVariables(currentScope, this.preIncrementsInitStateIndex); |
| } |
| // continuation point |
| if (this.continueLabel != null) { |
| this.continueLabel.place(); |
| // generate the increments for next iteration |
| if (this.increments != null) { |
| for (int i = 0, max = this.increments.length; i < max; i++) { |
| this.increments[i].generateCode(this.scope, codeStream); |
| } |
| } |
| // May loose some local variable initializations : affecting the local variable attributes |
| if (this.preCondInitStateIndex != -1) { |
| codeStream.removeNotDefinitelyAssignedVariables(currentScope, this.preCondInitStateIndex); |
| } |
| // generate the condition |
| conditionLabel.place(); |
| if ((this.condition != null) && (this.condition.constant == Constant.NotAConstant)) { |
| this.condition.generateOptimizedBoolean(this.scope, codeStream, actionLabel, null, true); |
| } else { |
| codeStream.goto_(actionLabel); |
| } |
| |
| } else { |
| // May loose some local variable initializations : affecting the local variable attributes |
| if (this.preCondInitStateIndex != -1) { |
| codeStream.removeNotDefinitelyAssignedVariables(currentScope, this.preCondInitStateIndex); |
| } |
| } |
| |
| |
| // May loose some local variable initializations : affecting the local variable attributes |
| if ((this.bits & ASTNode.NeededScope) != 0) { |
| codeStream.exitUserScope(this.scope); |
| } |
| if (this.mergedInitStateIndex != -1) { |
| codeStream.removeNotDefinitelyAssignedVariables(currentScope, this.mergedInitStateIndex); |
| codeStream.addDefinitelyAssignedVariables(currentScope, this.mergedInitStateIndex); |
| } |
| this.breakLabel.place(); |
| codeStream.recordPositionsFrom(pc, this.sourceStart); |
| } |
| |
| @Override |
| public StringBuffer printStatement(int tab, StringBuffer output) { |
| |
| printIndent(tab, output).append("for ("); //$NON-NLS-1$ |
| //inits |
| if (this.initializations != null) { |
| for (int i = 0; i < this.initializations.length; i++) { |
| //nice only with expressions |
| if (i > 0) output.append(", "); //$NON-NLS-1$ |
| this.initializations[i].print(0, output); |
| } |
| } |
| output.append("; "); //$NON-NLS-1$ |
| //cond |
| if (this.condition != null) this.condition.printExpression(0, output); |
| output.append("; "); //$NON-NLS-1$ |
| //updates |
| if (this.increments != null) { |
| for (int i = 0; i < this.increments.length; i++) { |
| if (i > 0) output.append(", "); //$NON-NLS-1$ |
| this.increments[i].print(0, output); |
| } |
| } |
| output.append(") "); //$NON-NLS-1$ |
| //block |
| if (this.action == null) |
| output.append(';'); |
| else { |
| output.append('\n'); |
| this.action.printStatement(tab + 1, output); |
| } |
| return output; |
| } |
| |
| @Override |
| public void resolve(BlockScope upperScope) { |
| //{ObjectTeams: don't discard scope from previous attempt: |
| if (this.scope == null) |
| // SH} |
| // use the scope that will hold the init declarations |
| this.scope = (this.bits & ASTNode.NeededScope) != 0 ? new BlockScope(upperScope) : upperScope; |
| if (this.initializations != null) |
| for (int i = 0, length = this.initializations.length; i < length; i++) |
| this.initializations[i].resolve(this.scope); |
| if (this.condition != null) { |
| TypeBinding type = this.condition.resolveTypeExpecting(this.scope, TypeBinding.BOOLEAN); |
| this.condition.computeConversion(this.scope, type, type); |
| } |
| if (this.increments != null) |
| for (int i = 0, length = this.increments.length; i < length; i++) |
| this.increments[i].resolve(this.scope); |
| if (this.action != null) |
| this.action.resolve(this.scope); |
| } |
| |
| @Override |
| public void traverse( |
| ASTVisitor visitor, |
| BlockScope blockScope) { |
| |
| if (visitor.visit(this, blockScope)) { |
| if (this.initializations != null) { |
| int initializationsLength = this.initializations.length; |
| for (int i = 0; i < initializationsLength; i++) |
| this.initializations[i].traverse(visitor, this.scope); |
| } |
| |
| if (this.condition != null) |
| this.condition.traverse(visitor, this.scope); |
| |
| if (this.increments != null) { |
| int incrementsLength = this.increments.length; |
| for (int i = 0; i < incrementsLength; i++) |
| this.increments[i].traverse(visitor, this.scope); |
| } |
| |
| if (this.action != null) |
| this.action.traverse(visitor, this.scope); |
| } |
| visitor.endVisit(this, blockScope); |
| } |
| |
| @Override |
| public boolean doesNotCompleteNormally() { |
| Constant cst = this.condition == null ? null : this.condition.constant; |
| boolean isConditionTrue = cst == null || cst != Constant.NotAConstant && cst.booleanValue() == true; |
| cst = this.condition == null ? null : this.condition.optimizedBooleanConstant(); |
| boolean isConditionOptimizedTrue = cst == null ? true : cst != Constant.NotAConstant && cst.booleanValue() == true; |
| |
| return (isConditionTrue || isConditionOptimizedTrue) && (this.action == null || !this.action.breaksOut(null)); |
| } |
| |
| @Override |
| public boolean completesByContinue() { |
| return this.action.continuesAtOuterLabel(); |
| } |
| } |