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/*******************************************************************************
* Copyright (c) 2000, 2011 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
* Stephan Herrmann - Contributions for
* bug 335093 - [compiler][null] minimal hook for future null annotation support
* bug 349326 - [1.7] new warning for missing try-with-resources
* bug 186342 - [compiler][null] Using annotations for null checking
* bug 365983 - [compiler][null] AIOOB with null annotation analysis and varargs
*******************************************************************************/
package org.eclipse.jdt.internal.compiler.ast;
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 abstract class Statement extends ASTNode {
/**
* Answers true if the if is identified as a known coding pattern which
* should be tolerated by dead code analysis.
* e.g. if (DEBUG) print(); // no complaint
* Only invoked when overall condition is known to be optimizeable into false/true.
*/
protected static boolean isKnowDeadCodePattern(Expression expression) {
// if (!DEBUG) print(); - tolerated
if (expression instanceof UnaryExpression) {
expression = ((UnaryExpression) expression).expression;
}
// if (DEBUG) print(); - tolerated
if (expression instanceof Reference) return true;
// if (expression instanceof BinaryExpression) {
// BinaryExpression binary = (BinaryExpression) expression;
// switch ((binary.bits & ASTNode.OperatorMASK) >> ASTNode.OperatorSHIFT/* operator */) {
// case OperatorIds.AND_AND :
// case OperatorIds.OR_OR :
// break;
// default:
// // if (DEBUG_LEVEL > 0) print(); - tolerated
// if ((binary.left instanceof Reference) && binary.right.constant != Constant.NotAConstant)
// return true;
// // if (0 < DEBUG_LEVEL) print(); - tolerated
// if ((binary.right instanceof Reference) && binary.left.constant != Constant.NotAConstant)
// return true;
// }
// }
return false;
}
public abstract FlowInfo analyseCode(BlockScope currentScope, FlowContext flowContext, FlowInfo flowInfo);
public static final int NOT_COMPLAINED = 0;
public static final int COMPLAINED_FAKE_REACHABLE = 1;
public static final int COMPLAINED_UNREACHABLE = 2;
/** Analysing arguments of MessageSend, ExplicitConstructorCall, AllocationExpression. */
protected void analyseArguments(BlockScope currentScope, FlowContext flowContext, FlowInfo flowInfo, MethodBinding methodBinding, Expression[] arguments)
{
// compare actual null-status against parameter annotations of the called method:
if (arguments != null && methodBinding.parameterNonNullness != null) {
// check if varargs need special treatment:
int numParamsToCheck = methodBinding.parameters.length;
boolean passThrough = false;
if (methodBinding.isVarargs()) {
int varArgPos = numParamsToCheck-1;
// this if-block essentially copied from generateArguments(..):
if (numParamsToCheck == arguments.length) {
TypeBinding varArgsType = methodBinding.parameters[varArgPos];
TypeBinding lastType = arguments[varArgPos].resolvedType;
if (lastType == TypeBinding.NULL
|| (varArgsType.dimensions() == lastType.dimensions()
&& lastType.isCompatibleWith(varArgsType)))
passThrough = true; // pass directly as-is
}
if (!passThrough)
numParamsToCheck--; // with non-passthrough varargs last param is fed from individual args -> don't check
}
for (int i = 0; i < numParamsToCheck; i++) {
if (methodBinding.parameterNonNullness[i] == Boolean.TRUE) {
TypeBinding expectedType = methodBinding.parameters[i];
Expression argument = arguments[i];
int nullStatus = argument.nullStatus(flowInfo); // slight loss of precision: should also use the null info from the receiver.
if (nullStatus != FlowInfo.NON_NULL) // if required non-null is not provided
flowContext.recordNullityMismatch(currentScope, argument, nullStatus, expectedType);
}
}
}
}
/** Check null-ness of 'local' against a possible null annotation */
protected int checkAssignmentAgainstNullAnnotation(BlockScope currentScope, FlowContext flowContext,
VariableBinding var, int nullStatus, Expression expression)
{
if (var != null
&& (var.tagBits & TagBits.AnnotationNonNull) != 0
&& nullStatus != FlowInfo.NON_NULL) {
flowContext.recordNullityMismatch(currentScope, expression, nullStatus, var.type);
nullStatus=FlowInfo.NON_NULL;
}
return nullStatus;
}
/**
* INTERNAL USE ONLY.
* This is used to redirect inter-statements jumps.
*/
public void branchChainTo(BranchLabel label) {
// do nothing by default
}
// Report an error if necessary (if even more unreachable than previously reported
// complaintLevel = 0 if was reachable up until now, 1 if fake reachable (deadcode), 2 if fatal unreachable (error)
public int complainIfUnreachable(FlowInfo flowInfo, BlockScope scope, int previousComplaintLevel, boolean endOfBlock) {
if ((flowInfo.reachMode() & FlowInfo.UNREACHABLE) != 0) {
if ((flowInfo.reachMode() & FlowInfo.UNREACHABLE_OR_DEAD) != 0)
this.bits &= ~ASTNode.IsReachable;
if (flowInfo == FlowInfo.DEAD_END) {
if (previousComplaintLevel < COMPLAINED_UNREACHABLE) {
scope.problemReporter().unreachableCode(this);
if (endOfBlock)
scope.checkUnclosedCloseables(flowInfo, null, null);
}
return COMPLAINED_UNREACHABLE;
} else {
if (previousComplaintLevel < COMPLAINED_FAKE_REACHABLE) {
scope.problemReporter().fakeReachable(this);
if (endOfBlock)
scope.checkUnclosedCloseables(flowInfo, null, null);
}
return COMPLAINED_FAKE_REACHABLE;
}
}
return previousComplaintLevel;
}
/**
* Generate invocation arguments, considering varargs methods
*/
public void generateArguments(MethodBinding binding, Expression[] arguments, BlockScope currentScope, CodeStream codeStream) {
if (binding.isVarargs()) {
// 5 possibilities exist for a call to the vararg method foo(int i, int ... value) :
// foo(1), foo(1, null), foo(1, 2), foo(1, 2, 3, 4) & foo(1, new int[] {1, 2})
TypeBinding[] params = binding.parameters;
int paramLength = params.length;
int varArgIndex = paramLength - 1;
for (int i = 0; i < varArgIndex; i++) {
arguments[i].generateCode(currentScope, codeStream, true);
}
ArrayBinding varArgsType = (ArrayBinding) params[varArgIndex]; // parameterType has to be an array type
ArrayBinding codeGenVarArgsType = (ArrayBinding) binding.parameters[varArgIndex].erasure();
int elementsTypeID = varArgsType.elementsType().id;
int argLength = arguments == null ? 0 : arguments.length;
if (argLength > paramLength) {
// right number but not directly compatible or too many arguments - wrap extra into array
// called with (argLength - lastIndex) elements : foo(1, 2) or foo(1, 2, 3, 4)
// need to gen elements into an array, then gen each remaining element into created array
codeStream.generateInlinedValue(argLength - varArgIndex);
codeStream.newArray(codeGenVarArgsType); // create a mono-dimensional array
for (int i = varArgIndex; i < argLength; i++) {
codeStream.dup();
codeStream.generateInlinedValue(i - varArgIndex);
arguments[i].generateCode(currentScope, codeStream, true);
codeStream.arrayAtPut(elementsTypeID, false);
}
} else if (argLength == paramLength) {
// right number of arguments - could be inexact - pass argument as is
TypeBinding lastType = arguments[varArgIndex].resolvedType;
if (lastType == TypeBinding.NULL
|| (varArgsType.dimensions() == lastType.dimensions()
&& lastType.isCompatibleWith(varArgsType))) {
// foo(1, new int[]{2, 3}) or foo(1, null) --> last arg is passed as-is
arguments[varArgIndex].generateCode(currentScope, codeStream, true);
} else {
// right number but not directly compatible or too many arguments - wrap extra into array
// need to gen elements into an array, then gen each remaining element into created array
codeStream.generateInlinedValue(1);
codeStream.newArray(codeGenVarArgsType); // create a mono-dimensional array
codeStream.dup();
codeStream.generateInlinedValue(0);
arguments[varArgIndex].generateCode(currentScope, codeStream, true);
codeStream.arrayAtPut(elementsTypeID, false);
}
} else { // not enough arguments - pass extra empty array
// scenario: foo(1) --> foo(1, new int[0])
// generate code for an empty array of parameterType
codeStream.generateInlinedValue(0);
codeStream.newArray(codeGenVarArgsType); // create a mono-dimensional array
}
} else if (arguments != null) { // standard generation for method arguments
for (int i = 0, max = arguments.length; i < max; i++)
arguments[i].generateCode(currentScope, codeStream, true);
}
}
public abstract void generateCode(BlockScope currentScope, CodeStream codeStream);
protected boolean isBoxingCompatible(TypeBinding expressionType, TypeBinding targetType, Expression expression, Scope scope) {
if (scope.isBoxingCompatibleWith(expressionType, targetType))
return true;
return expressionType.isBaseType() // narrowing then boxing ? Only allowed for some target types see 362279
&& !targetType.isBaseType()
&& !targetType.isTypeVariable()
&& scope.compilerOptions().sourceLevel >= org.eclipse.jdt.internal.compiler.classfmt.ClassFileConstants.JDK1_5 // autoboxing
&& (targetType.id == TypeIds.T_JavaLangByte || targetType.id == TypeIds.T_JavaLangShort || targetType.id == TypeIds.T_JavaLangCharacter)
&& expression.isConstantValueOfTypeAssignableToType(expressionType, scope.environment().computeBoxingType(targetType));
}
public boolean isEmptyBlock() {
return false;
}
public boolean isValidJavaStatement() {
//the use of this method should be avoid in most cases
//and is here mostly for documentation purpose.....
//while the parser is responsible for creating
//welled formed expression statement, which results
//in the fact that java-non-semantic-expression-used-as-statement
//should not be parsed...thus not being built.
//It sounds like the java grammar as help the compiler job in removing
//-by construction- some statement that would have no effect....
//(for example all expression that may do side-effects are valid statement
// -this is an approximative idea.....-)
return true;
}
public StringBuffer print(int indent, StringBuffer output) {
return printStatement(indent, output);
}
public abstract StringBuffer printStatement(int indent, StringBuffer output);
public abstract void resolve(BlockScope scope);
/**
* Returns case constant associated to this statement (NotAConstant if none)
*/
public Constant resolveCase(BlockScope scope, TypeBinding testType, SwitchStatement switchStatement) {
// statement within a switch that are not case are treated as normal statement....
resolve(scope);
return Constant.NotAConstant;
}
/**
* Implementation of {@link org.eclipse.jdt.internal.compiler.lookup.InvocationSite#expectedType}
* suitable at this level. Subclasses should override as necessary.
* @see org.eclipse.jdt.internal.compiler.lookup.InvocationSite#expectedType()
*/
public TypeBinding expectedType() {
return null;
}
}
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