Java TypeBinding.NULL属性代码示例

private TypeBinding getBaseTypeBinding(char[] signature) {
	switch (signature[0]) {
		case 'I' :
			return TypeBinding.INT;
		case 'Z' :
			return TypeBinding.BOOLEAN;
		case 'V' :
			return TypeBinding.VOID;
		case 'C' :
			return TypeBinding.CHAR;
		case 'D' :
			return TypeBinding.DOUBLE;
		case 'B' :
			return TypeBinding.BYTE;
		case 'F' :
			return TypeBinding.FLOAT;
		case 'J' :
			return TypeBinding.LONG;
		case 'S' :
			return TypeBinding.SHORT;
		case 'N':
			return TypeBinding.NULL;
		default :
			return null;
	}
}
 

private static int checkInvocationArgument(BlockScope scope, Expression argument, TypeBinding parameterType, TypeBinding argumentType, TypeBinding originalParameterType) {
	argument.computeConversion(scope, parameterType, argumentType);

	if (argumentType != TypeBinding.NULL && parameterType.kind() == Binding.WILDCARD_TYPE) { // intersection types are tolerated
		WildcardBinding wildcard = (WildcardBinding) parameterType;
		if (wildcard.boundKind != Wildcard.SUPER) {
	    	return INVOCATION_ARGUMENT_WILDCARD;
		}
	}
	TypeBinding checkedParameterType = parameterType; // originalParameterType == null ? parameterType : originalParameterType;
	if (TypeBinding.notEquals(argumentType, checkedParameterType) && argumentType.needsUncheckedConversion(checkedParameterType)) {
		scope.problemReporter().unsafeTypeConversion(argument, argumentType, checkedParameterType);
		return INVOCATION_ARGUMENT_UNCHECKED;
	}
	return INVOCATION_ARGUMENT_OK;
}
 

/**
 * Casting an enclosing instance will considered as useful if removing it would actually bind to a different type
 */
public static void checkNeedForEnclosingInstanceCast(BlockScope scope, Expression enclosingInstance, TypeBinding enclosingInstanceType, TypeBinding memberType) {
	if (scope.compilerOptions().getSeverity(CompilerOptions.UnnecessaryTypeCheck) == ProblemSeverities.Ignore) return;

	TypeBinding castedExpressionType = ((CastExpression)enclosingInstance).expression.resolvedType;
	if (castedExpressionType == null) return; // cannot do better
	// obvious identity cast
	if (TypeBinding.equalsEquals(castedExpressionType, enclosingInstanceType)) {
		scope.problemReporter().unnecessaryCast((CastExpression)enclosingInstance);
	} else if (castedExpressionType == TypeBinding.NULL){
		return; // tolerate null enclosing instance cast
	} else {
		TypeBinding alternateEnclosingInstanceType = castedExpressionType;
		if (castedExpressionType.isBaseType() || castedExpressionType.isArrayType()) return; // error case
		if (TypeBinding.equalsEquals(memberType, scope.getMemberType(memberType.sourceName(), (ReferenceBinding) alternateEnclosingInstanceType))) {
			scope.problemReporter().unnecessaryCast((CastExpression)enclosingInstance);
		}
	}
}
 

/**
 * Casting an enclosing instance will considered as useful if removing it would actually bind to a different type
 */
public static void checkNeedForEnclosingInstanceCast(BlockScope scope, Expression enclosingInstance, TypeBinding enclosingInstanceType, TypeBinding memberType) {
	if (scope.compilerOptions().getSeverity(CompilerOptions.UnnecessaryTypeCheck) == ProblemSeverities.Ignore) return;

	TypeBinding castedExpressionType = ((CastExpression)enclosingInstance).expression.resolvedType;
	if (castedExpressionType == null) return; // cannot do better
	// obvious identity cast
	if (castedExpressionType == enclosingInstanceType) {
		scope.problemReporter().unnecessaryCast((CastExpression)enclosingInstance);
	} else if (castedExpressionType == TypeBinding.NULL){
		return; // tolerate null enclosing instance cast
	} else {
		TypeBinding alternateEnclosingInstanceType = castedExpressionType;
		if (castedExpressionType.isBaseType() || castedExpressionType.isArrayType()) return; // error case
		if (memberType == scope.getMemberType(memberType.sourceName(), (ReferenceBinding) alternateEnclosingInstanceType)) {
			scope.problemReporter().unnecessaryCast((CastExpression)enclosingInstance);
		}
	}
}
 

/**
 * Before analyzing an assignment of this shape: <code>singleName = new Allocation()</code>
 * connect any tracking variable of the LHS with the allocation on the RHS.
 * Also the assignment is temporarily stored in the tracking variable in case we need to
 * report errors because the assignment leaves the old LHS value unclosed.
 * In this case the assignment should be used as the error location.
 * 
 * @param location the assignment/local declaration being analyzed
 * @param local the local variable being assigned to
 * @param rhs the rhs of the assignment resp. the initialization of the local variable declaration.
 * 		<strong>Precondition:</strong> client has already checked that the resolved type of this expression is either a closeable type or NULL.
 */
public static void preConnectTrackerAcrossAssignment(ASTNode location, LocalVariableBinding local, Expression rhs) {
	FakedTrackingVariable closeTracker = null;
	if (rhs instanceof AllocationExpression) {
		closeTracker = local.closeTracker;
		if (closeTracker == null) {
			if (rhs.resolvedType != TypeBinding.NULL) { // not NULL means valid closeable as per method precondition
				closeTracker = new FakedTrackingVariable(local, location);
				if (local.isParameter()) {
					closeTracker.globalClosingState |= OWNED_BY_OUTSIDE;
				}
			}					
		}
		if (closeTracker != null) {
			closeTracker.currentAssignment = location;
			AllocationExpression allocation = (AllocationExpression)rhs;
			allocation.closeTracker = closeTracker;
			if (allocation.arguments != null && allocation.arguments.length > 0) {
				// also push into nested allocations, see https://bugs.eclipse.org/368709
				preConnectTrackerAcrossAssignment(location, local, allocation.arguments[0]);
			}
		}
	}
}
 

public void generateStoreSaveValueIfNecessary(CodeStream codeStream){

	// push receiver
	codeStream.aload_0();

	// push the 2 parameters of "setResult(Object, Class)"
	if (this.expression == null || this.expression.resolvedType == TypeBinding.VOID) { // expressionType == VoidBinding if code snippet is the expression "System.out.println()"
		// push null
		codeStream.aconst_null();

		// void.class
		codeStream.generateClassLiteralAccessForType(TypeBinding.VOID, null);
	} else {
		// swap with expression
		int valueTypeID = this.expression.resolvedType.id;
		if (valueTypeID == T_long || valueTypeID == T_double) {
			codeStream.dup_x2();
			codeStream.pop();
		} else {
			codeStream.swap();
		}

		// generate wrapper if needed
		if (this.expression.resolvedType.isBaseType() && this.expression.resolvedType != TypeBinding.NULL) {
			codeStream.generateBoxingConversion(this.expression.resolvedType.id);
		}

		// generate the expression type
		codeStream.generateClassLiteralAccessForType(this.expression.resolvedType, null);
	}

	// generate the invoke virtual to "setResult(Object,Class)"
	codeStream.invoke(Opcodes.OPC_invokevirtual, this.setResultMethod, null /* default declaringClass */);
}
 

public void generateAssignment(BlockScope currentScope, CodeStream codeStream, Assignment assignment, boolean valueRequired) {
	int pc = codeStream.position;
	this.receiver.generateCode(currentScope, codeStream, true);
	if (this.receiver instanceof CastExpression	// ((type[])null)[0]
			&& ((CastExpression)this.receiver).innermostCastedExpression().resolvedType == TypeBinding.NULL){
		codeStream.checkcast(this.receiver.resolvedType);
	}
	codeStream.recordPositionsFrom(pc, this.sourceStart);
	this.position.generateCode(currentScope, codeStream, true);
	assignment.expression.generateCode(currentScope, codeStream, true);
	codeStream.arrayAtPut(this.resolvedType.id, valueRequired);
	if (valueRequired) {
		codeStream.generateImplicitConversion(assignment.implicitConversion);
	}
}
 

/**
 * Code generation for a array reference
 */
public void generateCode(BlockScope currentScope, CodeStream codeStream, boolean valueRequired) {
	int pc = codeStream.position;
	this.receiver.generateCode(currentScope, codeStream, true);
	if (this.receiver instanceof CastExpression	// ((type[])null)[0]
			&& ((CastExpression)this.receiver).innermostCastedExpression().resolvedType == TypeBinding.NULL){
		codeStream.checkcast(this.receiver.resolvedType);
	}
	this.position.generateCode(currentScope, codeStream, true);
	codeStream.arrayAt(this.resolvedType.id);
	// Generating code for the potential runtime type checking
	if (valueRequired) {
		codeStream.generateImplicitConversion(this.implicitConversion);
	} else {
		boolean isUnboxing = (this.implicitConversion & TypeIds.UNBOXING) != 0;
		// conversion only generated if unboxing
		if (isUnboxing) codeStream.generateImplicitConversion(this.implicitConversion);
		switch (isUnboxing ? postConversionType(currentScope).id : this.resolvedType.id) {
			case T_long :
			case T_double :
				codeStream.pop2();
				break;
			default :
				codeStream.pop();
		}
	}
	codeStream.recordPositionsFrom(pc, this.sourceStart);
}
 

public void generateCompoundAssignment(BlockScope currentScope, CodeStream codeStream, Expression expression, int operator, int assignmentImplicitConversion, boolean valueRequired) {
	this.receiver.generateCode(currentScope, codeStream, true);
	if (this.receiver instanceof CastExpression	// ((type[])null)[0]
			&& ((CastExpression)this.receiver).innermostCastedExpression().resolvedType == TypeBinding.NULL){
		codeStream.checkcast(this.receiver.resolvedType);
	}
	this.position.generateCode(currentScope, codeStream, true);
	codeStream.dup2();
	codeStream.arrayAt(this.resolvedType.id);
	int operationTypeID;
	switch(operationTypeID = (this.implicitConversion & TypeIds.IMPLICIT_CONVERSION_MASK) >> 4) {
		case T_JavaLangString :
		case T_JavaLangObject :
		case T_undefined :
			codeStream.generateStringConcatenationAppend(currentScope, null, expression);
			break;
		default :
			// promote the array reference to the suitable operation type
			codeStream.generateImplicitConversion(this.implicitConversion);
			// generate the increment value (will by itself  be promoted to the operation value)
			if (expression == IntLiteral.One) { // prefix operation
				codeStream.generateConstant(expression.constant, this.implicitConversion);
			} else {
				expression.generateCode(currentScope, codeStream, true);
			}
			// perform the operation
			codeStream.sendOperator(operator, operationTypeID);
			// cast the value back to the array reference type
			codeStream.generateImplicitConversion(assignmentImplicitConversion);
	}
	codeStream.arrayAtPut(this.resolvedType.id, valueRequired);
}
 

public void generatePostIncrement(BlockScope currentScope, CodeStream codeStream, CompoundAssignment postIncrement, boolean valueRequired) {
	this.receiver.generateCode(currentScope, codeStream, true);
	if (this.receiver instanceof CastExpression	// ((type[])null)[0]
			&& ((CastExpression)this.receiver).innermostCastedExpression().resolvedType == TypeBinding.NULL){
		codeStream.checkcast(this.receiver.resolvedType);
	}
	this.position.generateCode(currentScope, codeStream, true);
	codeStream.dup2();
	codeStream.arrayAt(this.resolvedType.id);
	if (valueRequired) {
		switch(this.resolvedType.id) {
			case TypeIds.T_long :
			case TypeIds.T_double :
				codeStream.dup2_x2();
				break;
			default :
				codeStream.dup_x2();
				break;
		}
	}
	codeStream.generateImplicitConversion(this.implicitConversion);
	codeStream.generateConstant(
		postIncrement.expression.constant,
		this.implicitConversion);
	codeStream.sendOperator(postIncrement.operator, this.implicitConversion & TypeIds.COMPILE_TYPE_MASK);
	codeStream.generateImplicitConversion(
		postIncrement.preAssignImplicitConversion);
	codeStream.arrayAtPut(this.resolvedType.id, false);
}
 

public void resolve(BlockScope scope) {
	this.exceptionType = this.exception.resolveType(scope);
	recordExceptionsForEnclosingLambda(scope, this.exceptionType);
	if (this.exceptionType != null && this.exceptionType.isValidBinding()) {
		if (this.exceptionType == TypeBinding.NULL) {
			if (scope.compilerOptions().complianceLevel <= ClassFileConstants.JDK1_3){
				// if compliant with 1.4, this problem will not be reported
				scope.problemReporter().cannotThrowNull(this.exception);
			}
	 	} else if (this.exceptionType.findSuperTypeOriginatingFrom(TypeIds.T_JavaLangThrowable, true) == null) {
			scope.problemReporter().cannotThrowType(this.exception, this.exceptionType);
		}
		this.exception.computeConversion(scope, this.exceptionType, this.exceptionType);
	}
}
 

/**
 * Cast expressions will considered as useful if removing them all would actually bind to a different method
 * (no fine grain analysis on per casted argument basis, simply separate widening cast from narrowing ones)
 */
public static void checkNeedForArgumentCasts(BlockScope scope, Expression receiver, TypeBinding receiverType, MethodBinding binding, Expression[] arguments, TypeBinding[] argumentTypes, final InvocationSite invocationSite) {
	if (scope.compilerOptions().getSeverity(CompilerOptions.UnnecessaryTypeCheck) == ProblemSeverities.Ignore) return;

	int length = argumentTypes.length;

	// iterate over arguments, and retrieve original argument types (before cast)
	TypeBinding[] rawArgumentTypes = argumentTypes;
	for (int i = 0; i < length; i++) {
		Expression argument = arguments[i];
		if (argument instanceof CastExpression) {
			// narrowing conversion on base type may change value, thus necessary
			if ((argument.bits & ASTNode.UnnecessaryCast) == 0 && argument.resolvedType.isBaseType()) {
				continue;
			}
			TypeBinding castedExpressionType = ((CastExpression)argument).expression.resolvedType;
			if (castedExpressionType == null) return; // cannot do better
			// obvious identity cast
			if (castedExpressionType == argumentTypes[i]) {
				scope.problemReporter().unnecessaryCast((CastExpression)argument);
			} else if (castedExpressionType == TypeBinding.NULL){
				continue; // tolerate null argument cast
			} else if ((argument.implicitConversion & TypeIds.BOXING) != 0) {
				continue; // boxing has a side effect: (int) char   is not boxed as simple char
			} else {
				if (rawArgumentTypes == argumentTypes) {
					System.arraycopy(rawArgumentTypes, 0, rawArgumentTypes = new TypeBinding[length], 0, length);
				}
				// retain original argument type
				rawArgumentTypes[i] = castedExpressionType;
			}
		}
	}
	// perform alternate lookup with original types
	if (rawArgumentTypes != argumentTypes) {
		checkAlternateBinding(scope, receiver, receiverType, binding, arguments, argumentTypes, rawArgumentTypes, invocationSite);
	}
}
 

public void generateCode(BlockScope currentScope, CodeStream codeStream, 	boolean valueRequired) {
	int pc = codeStream.position;
	MethodBinding codegenBinding = this.binding.original();
	ReferenceBinding allocatedType = codegenBinding.declaringClass;

	if (codegenBinding.canBeSeenBy(allocatedType, this, currentScope)) {
		codeStream.new_(this.type, allocatedType);
		if (valueRequired) {
			codeStream.dup();
		}
		// better highlight for allocation: display the type individually
		codeStream.recordPositionsFrom(pc, this.type.sourceStart);

		// handling innerclass instance allocation - enclosing instance arguments
		if (allocatedType.isNestedType()) {
			codeStream.generateSyntheticEnclosingInstanceValues(
				currentScope,
				allocatedType,
				enclosingInstance(),
				this);
		}
		// generate the arguments for constructor
		if (this.arguments != null) {
			for (int i = 0, count = this.arguments.length; i < count; i++) {
				this.arguments[i].generateCode(currentScope, codeStream, true);
			}
		}
		// handling innerclass instance allocation - outer local arguments
		if (allocatedType.isNestedType()) {
			codeStream.generateSyntheticOuterArgumentValues(
				currentScope,
				allocatedType,
				this);
		}
		// invoke constructor
		codeStream.invoke(Opcodes.OPC_invokespecial, codegenBinding, null /* default declaringClass */, this.typeArguments);
	} else {
		// private emulation using reflect
		codeStream.generateEmulationForConstructor(currentScope, codegenBinding);
		// generate arguments
		if (this.arguments != null) {
			int argsLength = this.arguments.length;
			codeStream.generateInlinedValue(argsLength);
			codeStream.newArray(currentScope.createArrayType(currentScope.getType(TypeConstants.JAVA_LANG_OBJECT, 3), 1));
			codeStream.dup();
			for (int i = 0; i < argsLength; i++) {
				codeStream.generateInlinedValue(i);
				this.arguments[i].generateCode(currentScope, codeStream, true);
				TypeBinding parameterBinding = codegenBinding.parameters[i];
				if (parameterBinding.isBaseType() && parameterBinding != TypeBinding.NULL) {
					codeStream.generateBoxingConversion(codegenBinding.parameters[i].id);
				}
				codeStream.aastore();
				if (i < argsLength - 1) {
					codeStream.dup();
				}
			}
		} else {
			codeStream.generateInlinedValue(0);
			codeStream.newArray(currentScope.createArrayType(currentScope.getType(TypeConstants.JAVA_LANG_OBJECT, 3), 1));
		}
		codeStream.invokeJavaLangReflectConstructorNewInstance();
		codeStream.checkcast(allocatedType);
	}
	codeStream.recordPositionsFrom(pc, this.sourceStart);
}
 

/**
 * Base types need that the widening is explicitly done by the compiler using some bytecode like i2f.
 * Also check unsafe type operations.
 */
public void computeConversion(Scope scope, TypeBinding runtimeType, TypeBinding compileTimeType) {
	if (runtimeType == null || compileTimeType == null)
		return;
	if (this.implicitConversion != 0) return; // already set independantly

	// it is possible for a Byte to be unboxed to a byte & then converted to an int
	// but it is not possible for a byte to become Byte & then assigned to an Integer,
	// or to become an int before boxed into an Integer
	if (runtimeType != TypeBinding.NULL && runtimeType.isBaseType()) {
		if (!compileTimeType.isBaseType()) {
			TypeBinding unboxedType = scope.environment().computeBoxingType(compileTimeType);
			this.implicitConversion = TypeIds.UNBOXING;
			scope.problemReporter().autoboxing(this, compileTimeType, runtimeType);
			compileTimeType = unboxedType;
		}
	} else if (compileTimeType != TypeBinding.NULL && compileTimeType.isBaseType()) {
		TypeBinding boxedType = scope.environment().computeBoxingType(runtimeType);
		if (boxedType == runtimeType) // Object o = 12;
			boxedType = compileTimeType;
		this.implicitConversion = TypeIds.BOXING | (boxedType.id << 4) + compileTimeType.id;
		scope.problemReporter().autoboxing(this, compileTimeType, scope.environment().computeBoxingType(boxedType));
		return;
	} else if (this.constant != Constant.NotAConstant && this.constant.typeID() != TypeIds.T_JavaLangString) {
		this.implicitConversion = TypeIds.BOXING;
		return;
	}
	int compileTimeTypeID, runtimeTypeID;
	if ((compileTimeTypeID = compileTimeType.id) == TypeIds.NoId) { // e.g. ? extends String  ==> String (103227)
		compileTimeTypeID = compileTimeType.erasure().id == TypeIds.T_JavaLangString ? TypeIds.T_JavaLangString : TypeIds.T_JavaLangObject;
	}
	switch (runtimeTypeID = runtimeType.id) {
		case T_byte :
		case T_short :
		case T_char :
			if (compileTimeTypeID == TypeIds.T_JavaLangObject) {
				this.implicitConversion |= (runtimeTypeID << 4) + compileTimeTypeID;
			} else {
				this.implicitConversion |= (TypeIds.T_int << 4) + compileTimeTypeID;
			}
			break;
		case T_JavaLangString :
		case T_float :
		case T_boolean :
		case T_double :
		case T_int : //implicitConversion may result in i2i which will result in NO code gen
		case T_long :
			this.implicitConversion |= (runtimeTypeID << 4) + compileTimeTypeID;
			break;
		default : // regular object ref
//				if (compileTimeType.isRawType() && runtimeTimeType.isBoundParameterizedType()) {
//				    scope.problemReporter().unsafeRawExpression(this, compileTimeType, runtimeTimeType);
//				}
	}
}
 

/**
 * Base types need that the widening is explicitly done by the compiler using some bytecode like i2f.
 * Also check unsafe type operations.
 */
public void computeConversion(Scope scope, TypeBinding runtimeType, TypeBinding compileTimeType) {
	if (runtimeType == null || compileTimeType == null)
		return;
	if (this.implicitConversion != 0) return; // already set independently

	// it is possible for a Byte to be unboxed to a byte & then converted to an int
	// but it is not possible for a byte to become Byte & then assigned to an Integer,
	// or to become an int before boxed into an Integer
	if (runtimeType != TypeBinding.NULL && runtimeType.isBaseType()) {
		if (!compileTimeType.isBaseType()) {
			TypeBinding unboxedType = scope.environment().computeBoxingType(compileTimeType);
			this.implicitConversion = TypeIds.UNBOXING;
			scope.problemReporter().autoboxing(this, compileTimeType, runtimeType);
			compileTimeType = unboxedType;
		}
	} else if (compileTimeType != TypeBinding.NULL && compileTimeType.isBaseType()) {
		TypeBinding boxedType = scope.environment().computeBoxingType(runtimeType);
		if (TypeBinding.equalsEquals(boxedType, runtimeType)) // Object o = 12;
			boxedType = compileTimeType;
		this.implicitConversion = TypeIds.BOXING | (boxedType.id << 4) + compileTimeType.id;
		scope.problemReporter().autoboxing(this, compileTimeType, scope.environment().computeBoxingType(boxedType));
		return;
	} else if (this.constant != Constant.NotAConstant && this.constant.typeID() != TypeIds.T_JavaLangString) {
		this.implicitConversion = TypeIds.BOXING;
		return;
	}
	int compileTimeTypeID, runtimeTypeID;
	if ((compileTimeTypeID = compileTimeType.id) >= TypeIds.T_LastWellKnownTypeId) { // e.g. ? extends String  ==> String (103227); >= TypeIds.T_LastWellKnownTypeId implies TypeIds.NoId
		compileTimeTypeID = compileTimeType.erasure().id == TypeIds.T_JavaLangString ? TypeIds.T_JavaLangString : TypeIds.T_JavaLangObject;
	} else if (runtimeType.isPrimitiveType() && compileTimeType instanceof ReferenceBinding && !compileTimeType.isBoxedPrimitiveType()) {
		compileTimeTypeID = TypeIds.T_JavaLangObject; // treatment is the same as for jlO.
	}

	switch (runtimeTypeID = runtimeType.id) {
		case T_byte :
		case T_short :
		case T_char :
			if (compileTimeTypeID == TypeIds.T_JavaLangObject) {
				this.implicitConversion |= (runtimeTypeID << 4) + compileTimeTypeID;
			} else {
				this.implicitConversion |= (TypeIds.T_int << 4) + compileTimeTypeID;
			}
			break;
		case T_JavaLangString :
		case T_float :
		case T_boolean :
		case T_double :
		case T_int : //implicitConversion may result in i2i which will result in NO code gen
		case T_long :
			this.implicitConversion |= (runtimeTypeID << 4) + compileTimeTypeID;
			break;
		default : // regular object ref
//				if (compileTimeType.isRawType() && runtimeTimeType.isBoundParameterizedType()) {
//				    scope.problemReporter().unsafeRawExpression(this, compileTimeType, runtimeTimeType);
//				}
	}
}