org.eclipse.jdt.core/compiler/org/eclipse/jdt/internal/compiler/ast/Reference.java - jdt/eclipse.jdt.core - Git at Google

 /*******************************************************************************
  * Copyright (c) 2000, 2019 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
  *     Stephan Herrmann <stephan@cs.tu-berlin.de> - Contributions for
  *								bug 185682 - Increment/decrement operators mark local variables as read
  *								bug 392862 - [1.8][compiler][null] Evaluate null annotations on array types
  *								bug 331649 - [compiler][null] consider null annotations for fields
  *								bug 383368 - [compiler][null] syntactic null analysis for field references
  *								bug 392384 - [1.8][compiler][null] Restore nullness info from type annotations in class files
  *								Bug 392099 - [1.8][compiler][null] Apply null annotation on types for null analysis
  *								Bug 411964 - [1.8][null] leverage null type annotation in foreach statement
  *								Bug 407414 - [compiler][null] Incorrect warning on a primitive type being null
  *******************************************************************************/
 package org.eclipse.jdt.internal.compiler.ast;

 import org.eclipse.jdt.internal.compiler.codegen.CodeStream;
 import org.eclipse.jdt.internal.compiler.codegen.Opcodes;
 import org.eclipse.jdt.internal.compiler.flow.FlowContext;
 import org.eclipse.jdt.internal.compiler.flow.FlowInfo;
 import org.eclipse.jdt.internal.compiler.impl.Constant;
 import org.eclipse.jdt.internal.compiler.lookup.BlockScope;
 import org.eclipse.jdt.internal.compiler.lookup.ExtraCompilerModifiers;
 import org.eclipse.jdt.internal.compiler.lookup.FieldBinding;
 import org.eclipse.jdt.internal.compiler.lookup.LocalVariableBinding;
 import org.eclipse.jdt.internal.compiler.lookup.MethodBinding;
 import org.eclipse.jdt.internal.compiler.lookup.MethodScope;
 import org.eclipse.jdt.internal.compiler.lookup.Scope;
 import org.eclipse.jdt.internal.compiler.lookup.TagBits;
 import org.eclipse.jdt.internal.compiler.lookup.TypeBinding;
 import org.eclipse.jdt.internal.compiler.lookup.TypeIds;

 public abstract class Reference extends Expression  {
 /**
  * BaseLevelReference constructor comment.
  */
 public Reference() {
 	super();
 }
 public abstract FlowInfo analyseAssignment(BlockScope currentScope, FlowContext flowContext, FlowInfo flowInfo, Assignment assignment, boolean isCompound);

 @Override
 public FlowInfo analyseCode(BlockScope currentScope, FlowContext flowContext, FlowInfo flowInfo) {
 	return flowInfo;
 }

 @Override
 public boolean checkNPE(BlockScope scope, FlowContext flowContext, FlowInfo flowInfo, int ttlForFieldCheck) {
 	if (flowContext.isNullcheckedFieldAccess(this)) {
 		return true; // enough seen
 	}
 	return super.checkNPE(scope, flowContext, flowInfo, ttlForFieldCheck);
 }

 protected boolean checkNullableFieldDereference(Scope scope, FieldBinding field, long sourcePosition, FlowContext flowContext, int ttlForFieldCheck) {
 	if (field != null) {
 		if (ttlForFieldCheck > 0 && scope.compilerOptions().enableSyntacticNullAnalysisForFields)
 			flowContext.recordNullCheckedFieldReference(this, ttlForFieldCheck);
 		// preference to type annotations if we have any
 		if ((field.type.tagBits & TagBits.AnnotationNullable) != 0) {
 			scope.problemReporter().dereferencingNullableExpression(sourcePosition, scope.environment());
 			return true;
 		}
 		if (field.type.isFreeTypeVariable()) {
 			scope.problemReporter().fieldFreeTypeVariableReference(field, sourcePosition);
 			return true;
 		}
 		if ((field.tagBits & TagBits.AnnotationNullable) != 0) {
 			scope.problemReporter().nullableFieldDereference(field, sourcePosition);
 			return true;
 		}
 	}
 	return false;
 }

 public FieldBinding fieldBinding() {
 	//this method should be sent one FIELD-tagged references
 	//  (ref.bits & BindingIds.FIELD != 0)()
 	return null ;
 }

 public void fieldStore(Scope currentScope, CodeStream codeStream, FieldBinding fieldBinding, MethodBinding syntheticWriteAccessor, TypeBinding receiverType, boolean isImplicitThisReceiver, boolean valueRequired) {
 	int pc = codeStream.position;
 	if (fieldBinding.isStatic()) {
 		if (valueRequired) {
 			switch (fieldBinding.type.id) {
 				case TypeIds.T_long :
 				case TypeIds.T_double :
 					codeStream.dup2();
 					break;
 				default :
 					codeStream.dup();
 					break;
 			}
 		}
 		if (syntheticWriteAccessor == null) {
 			TypeBinding constantPoolDeclaringClass = CodeStream.getConstantPoolDeclaringClass(currentScope, fieldBinding, receiverType, isImplicitThisReceiver);
 			codeStream.fieldAccess(Opcodes.OPC_putstatic, fieldBinding, constantPoolDeclaringClass);
 		} else {
 			codeStream.invoke(Opcodes.OPC_invokestatic, syntheticWriteAccessor, null /* default declaringClass */);
 		}
 	} else { // Stack:  [owner][new field value]  ---> [new field value][owner][new field value]
 		if (valueRequired) {
 			switch (fieldBinding.type.id) {
 				case TypeIds.T_long :
 				case TypeIds.T_double :
 					codeStream.dup2_x1();
 					break;
 				default :
 					codeStream.dup_x1();
 					break;
 			}
 		}
 		if (syntheticWriteAccessor == null) {
 			TypeBinding constantPoolDeclaringClass = CodeStream.getConstantPoolDeclaringClass(currentScope, fieldBinding, receiverType, isImplicitThisReceiver);
 			codeStream.fieldAccess(Opcodes.OPC_putfield, fieldBinding, constantPoolDeclaringClass);
 		} else {
 			codeStream.invoke(Opcodes.OPC_invokestatic, syntheticWriteAccessor, null /* default declaringClass */);
 		}
 	}
 	codeStream.recordPositionsFrom(pc, this.sourceStart);
 }

 public abstract void generateAssignment(BlockScope currentScope, CodeStream codeStream, Assignment assignment, boolean valueRequired);

 public abstract void generateCompoundAssignment(BlockScope currentScope, CodeStream codeStream, Expression expression, int operator, int assignmentImplicitConversion, boolean valueRequired);

 public abstract void generatePostIncrement(BlockScope currentScope, CodeStream codeStream, CompoundAssignment postIncrement, boolean valueRequired);

 /**
  * Is the given reference equivalent to the receiver,
  * meaning that both denote the same path of field reads?
  * Used from {@link FlowContext#isNullcheckedFieldAccess(Reference)}.
  */
 public boolean isEquivalent(Reference reference) {
 	return false;
 }

 public FieldBinding lastFieldBinding() {
 	// override to answer the field designated by the entire reference
 	// (as opposed to fieldBinding() which answers the first field in a QNR)
 	return null;
 }

 @Override
 public int nullStatus(FlowInfo flowInfo, FlowContext flowContext) {
 	if ((this.implicitConversion & TypeIds.BOXING) != 0)
 		return FlowInfo.NON_NULL;
 	FieldBinding fieldBinding = lastFieldBinding();
 	if (fieldBinding != null) {
 		if (fieldBinding.isFinal() && fieldBinding.constant() != Constant.NotAConstant)
 			return FlowInfo.NON_NULL;
 		if (fieldBinding.isNonNull() || flowContext.isNullcheckedFieldAccess(this)) {
 			return FlowInfo.NON_NULL;
 		} else if (fieldBinding.isNullable()) {
 			return FlowInfo.POTENTIALLY_NULL;
 		} else if (fieldBinding.type.isFreeTypeVariable()) {
 			return FlowInfo.FREE_TYPEVARIABLE;
 		}
 	}
 	if (this.resolvedType != null) {
 		return FlowInfo.tagBitsToNullStatus(this.resolvedType.tagBits);
 	}
 	return FlowInfo.UNKNOWN;
 }

 /* report if a private field is only read from a 'special operator',
  * i.e., in a postIncrement expression or a compound assignment,
  * where the information is never flowing out off the field. */
 void reportOnlyUselesslyReadPrivateField(BlockScope currentScope, FieldBinding fieldBinding, boolean valueRequired) {
 	if (valueRequired) {
 		// access is relevant, turn compound use into real use:
 		fieldBinding.compoundUseFlag = 0;
 		fieldBinding.modifiers |= ExtraCompilerModifiers.AccLocallyUsed;
 	} else {
 		if (fieldBinding.isUsedOnlyInCompound()) {
 			fieldBinding.compoundUseFlag--; // consume one
 			if (fieldBinding.compoundUseFlag == 0					// report only the last usage
 					&& fieldBinding.isOrEnclosedByPrivateType()
 					&& (this.implicitConversion & TypeIds.UNBOXING) == 0) // don't report if unboxing is involved (might cause NPE)
 			{
 				// compoundAssignment/postIncrement is the only usage of this field
 				currentScope.problemReporter().unusedPrivateField(fieldBinding.sourceField());
 			}
 		}
 	}
 }
 /* report a local/arg that is only read from a 'special operator',
  * i.e., in a postIncrement expression or a compound assignment,
  * where the information is never flowing out off the local/arg. */
 static void reportOnlyUselesslyReadLocal(BlockScope currentScope, LocalVariableBinding localBinding, boolean valueRequired) {
 	if (localBinding.declaration == null)
 		return;  // secret local
 	if ((localBinding.declaration.bits & ASTNode.IsLocalDeclarationReachable) == 0)
 		return;  // declaration is unreachable
 	if (localBinding.useFlag >= LocalVariableBinding.USED)
 		return;  // we're only interested in cases with only compound access (negative count)

 	if (valueRequired) {
 		// access is relevant
 		localBinding.useFlag = LocalVariableBinding.USED;
 		return;
 	} else {
 		localBinding.useFlag++;
 		if (localBinding.useFlag != LocalVariableBinding.UNUSED) // have all negative counts been consumed?
 			return; // still waiting to see more usages of this kind
 	}
 	// at this point we know we have something to report
 	if (localBinding.declaration instanceof Argument) {
 		// check compiler options to report against unused arguments
 		MethodScope methodScope = currentScope.methodScope();
 		if (methodScope != null && !methodScope.isLambdaScope()) { // lambda must be congruent with the descriptor.
 			MethodBinding method = ((AbstractMethodDeclaration)methodScope.referenceContext()).binding;

 			boolean shouldReport = !method.isMain();
 			if (method.isImplementing()) {
 				shouldReport &= currentScope.compilerOptions().reportUnusedParameterWhenImplementingAbstract;
 			} else if (method.isOverriding()) {
 				shouldReport &= currentScope.compilerOptions().reportUnusedParameterWhenOverridingConcrete;
 			}

 			if (shouldReport) {
 				// report the case of an argument that is unread except through a special operator
 				currentScope.problemReporter().unusedArgument(localBinding.declaration);
 			}
 		}
 	} else {
 		// report the case of a local variable that is unread except for a special operator
 		currentScope.problemReporter().unusedLocalVariable(localBinding.declaration);
 	}
 }
 }
	/*******************************************************************************
	* Copyright (c) 2000, 2019 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
	* Stephan Herrmann <stephan@cs.tu-berlin.de> - Contributions for
	* bug 185682 - Increment/decrement operators mark local variables as read
	* bug 392862 - [1.8][compiler][null] Evaluate null annotations on array types
	* bug 331649 - [compiler][null] consider null annotations for fields
	* bug 383368 - [compiler][null] syntactic null analysis for field references
	* bug 392384 - [1.8][compiler][null] Restore nullness info from type annotations in class files
	* Bug 392099 - [1.8][compiler][null] Apply null annotation on types for null analysis
	* Bug 411964 - [1.8][null] leverage null type annotation in foreach statement
	* Bug 407414 - [compiler][null] Incorrect warning on a primitive type being null
	*******************************************************************************/
	package org.eclipse.jdt.internal.compiler.ast;

	import org.eclipse.jdt.internal.compiler.codegen.CodeStream;
	import org.eclipse.jdt.internal.compiler.codegen.Opcodes;
	import org.eclipse.jdt.internal.compiler.flow.FlowContext;
	import org.eclipse.jdt.internal.compiler.flow.FlowInfo;
	import org.eclipse.jdt.internal.compiler.impl.Constant;
	import org.eclipse.jdt.internal.compiler.lookup.BlockScope;
	import org.eclipse.jdt.internal.compiler.lookup.ExtraCompilerModifiers;
	import org.eclipse.jdt.internal.compiler.lookup.FieldBinding;
	import org.eclipse.jdt.internal.compiler.lookup.LocalVariableBinding;
	import org.eclipse.jdt.internal.compiler.lookup.MethodBinding;
	import org.eclipse.jdt.internal.compiler.lookup.MethodScope;
	import org.eclipse.jdt.internal.compiler.lookup.Scope;
	import org.eclipse.jdt.internal.compiler.lookup.TagBits;
	import org.eclipse.jdt.internal.compiler.lookup.TypeBinding;
	import org.eclipse.jdt.internal.compiler.lookup.TypeIds;

	public abstract class Reference extends Expression {
	/**
	* BaseLevelReference constructor comment.
	*/
	public Reference() {
	super();
	}
	public abstract FlowInfo analyseAssignment(BlockScope currentScope, FlowContext flowContext, FlowInfo flowInfo, Assignment assignment, boolean isCompound);

	@Override
	public FlowInfo analyseCode(BlockScope currentScope, FlowContext flowContext, FlowInfo flowInfo) {
	return flowInfo;
	}

	@Override
	public boolean checkNPE(BlockScope scope, FlowContext flowContext, FlowInfo flowInfo, int ttlForFieldCheck) {
	if (flowContext.isNullcheckedFieldAccess(this)) {
	return true; // enough seen
	}
	return super.checkNPE(scope, flowContext, flowInfo, ttlForFieldCheck);
	}

	protected boolean checkNullableFieldDereference(Scope scope, FieldBinding field, long sourcePosition, FlowContext flowContext, int ttlForFieldCheck) {
	if (field != null) {
	if (ttlForFieldCheck > 0 && scope.compilerOptions().enableSyntacticNullAnalysisForFields)
	flowContext.recordNullCheckedFieldReference(this, ttlForFieldCheck);
	// preference to type annotations if we have any
	if ((field.type.tagBits & TagBits.AnnotationNullable) != 0) {
	scope.problemReporter().dereferencingNullableExpression(sourcePosition, scope.environment());
	return true;
	}
	if (field.type.isFreeTypeVariable()) {
	scope.problemReporter().fieldFreeTypeVariableReference(field, sourcePosition);
	return true;
	}
	if ((field.tagBits & TagBits.AnnotationNullable) != 0) {
	scope.problemReporter().nullableFieldDereference(field, sourcePosition);
	return true;
	}
	}
	return false;
	}

	public FieldBinding fieldBinding() {
	//this method should be sent one FIELD-tagged references
	// (ref.bits & BindingIds.FIELD != 0)()
	return null ;
	}

	public void fieldStore(Scope currentScope, CodeStream codeStream, FieldBinding fieldBinding, MethodBinding syntheticWriteAccessor, TypeBinding receiverType, boolean isImplicitThisReceiver, boolean valueRequired) {
	int pc = codeStream.position;
	if (fieldBinding.isStatic()) {
	if (valueRequired) {
	switch (fieldBinding.type.id) {
	case TypeIds.T_long :
	case TypeIds.T_double :
	codeStream.dup2();
	break;
	default :
	codeStream.dup();
	break;
	}
	}
	if (syntheticWriteAccessor == null) {
	TypeBinding constantPoolDeclaringClass = CodeStream.getConstantPoolDeclaringClass(currentScope, fieldBinding, receiverType, isImplicitThisReceiver);
	codeStream.fieldAccess(Opcodes.OPC_putstatic, fieldBinding, constantPoolDeclaringClass);
	} else {
	codeStream.invoke(Opcodes.OPC_invokestatic, syntheticWriteAccessor, null /* default declaringClass */);
	}
	} else { // Stack: [owner][new field value] ---> [new field value][owner][new field value]
	if (valueRequired) {
	switch (fieldBinding.type.id) {
	case TypeIds.T_long :
	case TypeIds.T_double :
	codeStream.dup2_x1();
	break;
	default :
	codeStream.dup_x1();
	break;
	}
	}
	if (syntheticWriteAccessor == null) {
	TypeBinding constantPoolDeclaringClass = CodeStream.getConstantPoolDeclaringClass(currentScope, fieldBinding, receiverType, isImplicitThisReceiver);
	codeStream.fieldAccess(Opcodes.OPC_putfield, fieldBinding, constantPoolDeclaringClass);
	} else {
	codeStream.invoke(Opcodes.OPC_invokestatic, syntheticWriteAccessor, null /* default declaringClass */);
	}
	}
	codeStream.recordPositionsFrom(pc, this.sourceStart);
	}

	public abstract void generateAssignment(BlockScope currentScope, CodeStream codeStream, Assignment assignment, boolean valueRequired);

	public abstract void generateCompoundAssignment(BlockScope currentScope, CodeStream codeStream, Expression expression, int operator, int assignmentImplicitConversion, boolean valueRequired);

	public abstract void generatePostIncrement(BlockScope currentScope, CodeStream codeStream, CompoundAssignment postIncrement, boolean valueRequired);

	/**
	* Is the given reference equivalent to the receiver,
	* meaning that both denote the same path of field reads?
	* Used from {@link FlowContext#isNullcheckedFieldAccess(Reference)}.
	*/
	public boolean isEquivalent(Reference reference) {
	return false;
	}

	public FieldBinding lastFieldBinding() {
	// override to answer the field designated by the entire reference
	// (as opposed to fieldBinding() which answers the first field in a QNR)
	return null;
	}

	@Override
	public int nullStatus(FlowInfo flowInfo, FlowContext flowContext) {
	if ((this.implicitConversion & TypeIds.BOXING) != 0)
	return FlowInfo.NON_NULL;
	FieldBinding fieldBinding = lastFieldBinding();
	if (fieldBinding != null) {
	if (fieldBinding.isFinal() && fieldBinding.constant() != Constant.NotAConstant)
	return FlowInfo.NON_NULL;
	if (fieldBinding.isNonNull() \|\| flowContext.isNullcheckedFieldAccess(this)) {
	return FlowInfo.NON_NULL;
	} else if (fieldBinding.isNullable()) {
	return FlowInfo.POTENTIALLY_NULL;
	} else if (fieldBinding.type.isFreeTypeVariable()) {
	return FlowInfo.FREE_TYPEVARIABLE;
	}
	}
	if (this.resolvedType != null) {
	return FlowInfo.tagBitsToNullStatus(this.resolvedType.tagBits);
	}
	return FlowInfo.UNKNOWN;
	}

	/* report if a private field is only read from a 'special operator',
	* i.e., in a postIncrement expression or a compound assignment,
	* where the information is never flowing out off the field. */
	void reportOnlyUselesslyReadPrivateField(BlockScope currentScope, FieldBinding fieldBinding, boolean valueRequired) {
	if (valueRequired) {
	// access is relevant, turn compound use into real use:
	fieldBinding.compoundUseFlag = 0;
	fieldBinding.modifiers \|= ExtraCompilerModifiers.AccLocallyUsed;
	} else {
	if (fieldBinding.isUsedOnlyInCompound()) {
	fieldBinding.compoundUseFlag--; // consume one
	if (fieldBinding.compoundUseFlag == 0 // report only the last usage
	&& fieldBinding.isOrEnclosedByPrivateType()
	&& (this.implicitConversion & TypeIds.UNBOXING) == 0) // don't report if unboxing is involved (might cause NPE)
	{
	// compoundAssignment/postIncrement is the only usage of this field
	currentScope.problemReporter().unusedPrivateField(fieldBinding.sourceField());
	}
	}
	}
	}
	/* report a local/arg that is only read from a 'special operator',
	* i.e., in a postIncrement expression or a compound assignment,
	* where the information is never flowing out off the local/arg. */
	static void reportOnlyUselesslyReadLocal(BlockScope currentScope, LocalVariableBinding localBinding, boolean valueRequired) {
	if (localBinding.declaration == null)
	return; // secret local
	if ((localBinding.declaration.bits & ASTNode.IsLocalDeclarationReachable) == 0)
	return; // declaration is unreachable
	if (localBinding.useFlag >= LocalVariableBinding.USED)
	return; // we're only interested in cases with only compound access (negative count)

	if (valueRequired) {
	// access is relevant
	localBinding.useFlag = LocalVariableBinding.USED;
	return;
	} else {
	localBinding.useFlag++;
	if (localBinding.useFlag != LocalVariableBinding.UNUSED) // have all negative counts been consumed?
	return; // still waiting to see more usages of this kind
	}
	// at this point we know we have something to report
	if (localBinding.declaration instanceof Argument) {
	// check compiler options to report against unused arguments
	MethodScope methodScope = currentScope.methodScope();
	if (methodScope != null && !methodScope.isLambdaScope()) { // lambda must be congruent with the descriptor.
	MethodBinding method = ((AbstractMethodDeclaration)methodScope.referenceContext()).binding;

	boolean shouldReport = !method.isMain();
	if (method.isImplementing()) {
	shouldReport &= currentScope.compilerOptions().reportUnusedParameterWhenImplementingAbstract;
	} else if (method.isOverriding()) {
	shouldReport &= currentScope.compilerOptions().reportUnusedParameterWhenOverridingConcrete;
	}

	if (shouldReport) {
	// report the case of an argument that is unread except through a special operator
	currentScope.problemReporter().unusedArgument(localBinding.declaration);
	}
	}
	} else {
	// report the case of a local variable that is unread except for a special operator
	currentScope.problemReporter().unusedLocalVariable(localBinding.declaration);
	}
	}
	}