/*******************************************************************************
* Copyright (c) 2000, 2009 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.BranchLabel;
import org.eclipse.jdt.internal.compiler.codegen.CaseLabel;
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.flow.SwitchFlowContext;
import org.eclipse.jdt.internal.compiler.impl.CompilerOptions;
import org.eclipse.jdt.internal.compiler.impl.Constant;
import org.eclipse.jdt.internal.compiler.lookup.BlockScope;
import org.eclipse.jdt.internal.compiler.lookup.FieldBinding;
import org.eclipse.jdt.internal.compiler.lookup.ReferenceBinding;
import org.eclipse.jdt.internal.compiler.lookup.SourceTypeBinding;
import org.eclipse.jdt.internal.compiler.lookup.SyntheticMethodBinding;
import org.eclipse.jdt.internal.compiler.lookup.TypeBinding;
import org.eclipse.jdt.internal.compiler.problem.ProblemSeverities;
public class SwitchStatement extends Statement {
public Expression expression;
public Statement[] statements;
public BlockScope scope;
public int explicitDeclarations;
public BranchLabel breakLabel;
public CaseStatement[] cases;
public CaseStatement defaultCase;
public int blockStart;
public int caseCount;
int[] constants;
// fallthrough
public final static int CASE= 0;
public final static int FALLTHROUGH= 1;
public final static int ESCAPING= 2;
public SyntheticMethodBinding synthetic; // use for switch on enums types
// for local variables table attributes
int preSwitchInitStateIndex= -1;
int mergedInitStateIndex= -1;
public FlowInfo analyseCode(BlockScope currentScope, FlowContext flowContext, FlowInfo flowInfo) {
try {
flowInfo= this.expression.analyseCode(currentScope, flowContext, flowInfo);
SwitchFlowContext switchContext=
new SwitchFlowContext(flowContext, this, (this.breakLabel= new BranchLabel()));
// analyse the block by considering specially the case/default statements (need to bind them
// to the entry point)
FlowInfo caseInits= FlowInfo.DEAD_END;
// in case of statements before the first case
this.preSwitchInitStateIndex= currentScope.methodScope().recordInitializationStates(flowInfo);
int caseIndex= 0;
if (this.statements != null) {
int initialComplaintLevel= (flowInfo.reachMode() & FlowInfo.UNREACHABLE) != 0 ? Statement.COMPLAINED_FAKE_REACHABLE : Statement.NOT_COMPLAINED;
int complaintLevel= initialComplaintLevel;
int fallThroughState= CASE;
for (int i= 0, max= this.statements.length; i < max; i++) {
Statement statement= this.statements[i];
if ((caseIndex < this.caseCount) && (statement == this.cases[caseIndex])) { // statement is a case
this.scope.enclosingCase= this.cases[caseIndex]; // record entering in a switch case block
caseIndex++;
if (fallThroughState == FALLTHROUGH
&& (statement.bits & ASTNode.DocumentedFallthrough) == 0) { // the case is not fall-through protected by a line comment
this.scope.problemReporter().possibleFallThroughCase(this.scope.enclosingCase);
}
caseInits= caseInits.mergedWith(flowInfo.unconditionalInits());
complaintLevel= initialComplaintLevel; // reset complaint
fallThroughState= CASE;
} else if (statement == this.defaultCase) { // statement is the default case
this.scope.enclosingCase= this.defaultCase; // record entering in a switch case block
if (fallThroughState == FALLTHROUGH
&& (statement.bits & ASTNode.DocumentedFallthrough) == 0) {
this.scope.problemReporter().possibleFallThroughCase(this.scope.enclosingCase);
}
caseInits= caseInits.mergedWith(flowInfo.unconditionalInits());
complaintLevel= initialComplaintLevel; // reset complaint
fallThroughState= CASE;
} else {
fallThroughState= FALLTHROUGH; // reset below if needed
}
if ((complaintLevel= statement.complainIfUnreachable(caseInits, this.scope, complaintLevel)) < Statement.COMPLAINED_UNREACHABLE) {
caseInits= statement.analyseCode(this.scope, switchContext, caseInits);
if (caseInits == FlowInfo.DEAD_END) {
fallThroughState= ESCAPING;
}
}
}
}
final TypeBinding resolvedTypeBinding= this.expression.resolvedType;
if (this.caseCount > 0 && resolvedTypeBinding.isEnum()) {
final SourceTypeBinding sourceTypeBinding= this.scope.classScope().referenceContext.binding;
this.synthetic= sourceTypeBinding.addSyntheticMethodForSwitchEnum(resolvedTypeBinding);
}
// if no default case, then record it may jump over the block directly to the end
if (this.defaultCase == null) {
// only retain the potential initializations
flowInfo.addPotentialInitializationsFrom(caseInits.mergedWith(switchContext.initsOnBreak));
this.mergedInitStateIndex= currentScope.methodScope().recordInitializationStates(flowInfo);
return flowInfo;
}
// merge all branches inits
FlowInfo mergedInfo= caseInits.mergedWith(switchContext.initsOnBreak);
this.mergedInitStateIndex=
currentScope.methodScope().recordInitializationStates(mergedInfo);
return mergedInfo;
} finally {
if (this.scope != null)
this.scope.enclosingCase= null; // no longer inside switch case block
}
}
/**
* Switch 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) {
try {
if ((this.bits & IsReachable) == 0) {
return;
}
int pc= codeStream.position;
// prepare the labels and constants
this.breakLabel.initialize(codeStream);
CaseLabel[] caseLabels= new CaseLabel[this.caseCount];
boolean needSwitch= this.caseCount != 0;
for (int i= 0; i < this.caseCount; i++) {
this.cases[i].targetLabel= (caseLabels[i]= new CaseLabel(codeStream));
caseLabels[i].tagBits|= BranchLabel.USED;
}
CaseLabel defaultLabel= new CaseLabel(codeStream);
if (needSwitch)
defaultLabel.tagBits|= BranchLabel.USED;
if (this.defaultCase != null) {
this.defaultCase.targetLabel= defaultLabel;
}
final TypeBinding resolvedType= this.expression.resolvedType;
if (resolvedType.isEnum()) {
if (needSwitch) {
// go through the translation table
codeStream.invoke(Opcodes.OPC_invokestatic, this.synthetic, null /* default declaringClass */);
this.expression.generateCode(currentScope, codeStream, true);
// get enum constant ordinal()
codeStream.invokeEnumOrdinal(resolvedType.constantPoolName());
codeStream.iaload();
} else {
// no need to go through the translation table
this.expression.generateCode(currentScope, codeStream, false);
}
} else {
// generate expression
this.expression.generateCode(currentScope, codeStream, needSwitch); // value required (switch without cases)
}
// generate the appropriate switch table/lookup bytecode
if (needSwitch) {
int[] sortedIndexes= new int[this.caseCount];
// we sort the keys to be able to generate the code for tableswitch or lookupswitch
for (int i= 0; i < this.caseCount; i++) {
sortedIndexes[i]= i;
}
int[] localKeysCopy;
System.arraycopy(this.constants, 0, (localKeysCopy= new int[this.caseCount]), 0, this.caseCount);
CodeStream.sort(localKeysCopy, 0, this.caseCount - 1, sortedIndexes);
int max= localKeysCopy[this.caseCount - 1];
int min= localKeysCopy[0];
if ((long)(this.caseCount * 2.5) > ((long)max - (long)min)) {
// work-around 1.3 VM bug, if max>0x7FFF0000, must use lookup bytecode
// see http://dev.eclipse.org/bugs/show_bug.cgi?id=21557
if (max > 0x7FFF0000 && currentScope.compilerOptions().complianceLevel < ClassFileConstants.JDK1_4) {
codeStream.lookupswitch(defaultLabel, this.constants, sortedIndexes, caseLabels);
} else {
codeStream.tableswitch(
defaultLabel,
min,
max,
this.constants,
sortedIndexes,
caseLabels);
}
} else {
codeStream.lookupswitch(defaultLabel, this.constants, sortedIndexes, caseLabels);
}
codeStream.updateLastRecordedEndPC(this.scope, codeStream.position);
}
// generate the switch block statements
int caseIndex= 0;
if (this.statements != null) {
for (int i= 0, maxCases= this.statements.length; i < maxCases; i++) {
Statement statement= this.statements[i];
if ((caseIndex < this.caseCount) && (statement == this.cases[caseIndex])) { // statements[i] is a case
this.scope.enclosingCase= this.cases[caseIndex]; // record entering in a switch case block
if (this.preSwitchInitStateIndex != -1) {
codeStream.removeNotDefinitelyAssignedVariables(currentScope, this.preSwitchInitStateIndex);
}
caseIndex++;
} else {
if (statement == this.defaultCase) { // statements[i] is a case or a default case
this.scope.enclosingCase= this.defaultCase; // record entering in a switch case block
if (this.preSwitchInitStateIndex != -1) {
codeStream.removeNotDefinitelyAssignedVariables(currentScope, this.preSwitchInitStateIndex);
}
}
}
statement.generateCode(this.scope, codeStream);
}
}
// May loose some local variable initializations : affecting the local variable attributes
if (this.mergedInitStateIndex != -1) {
codeStream.removeNotDefinitelyAssignedVariables(currentScope, this.mergedInitStateIndex);
codeStream.addDefinitelyAssignedVariables(currentScope, this.mergedInitStateIndex);
}
if (this.scope != currentScope) {
codeStream.exitUserScope(this.scope);
}
// place the trailing labels (for break and default case)
this.breakLabel.place();
if (this.defaultCase == null) {
// we want to force an line number entry to get an end position after the switch statement
codeStream.recordPositionsFrom(codeStream.position, this.sourceEnd, true);
defaultLabel.place();
}
codeStream.recordPositionsFrom(pc, this.sourceStart);
} finally {
if (this.scope != null)
this.scope.enclosingCase= null; // no longer inside switch case block
}
}
public StringBuffer printStatement(int indent, StringBuffer output) {
printIndent(indent, output).append("switch ("); //$NON-NLS-1$
this.expression.printExpression(0, output).append(") {"); //$NON-NLS-1$
if (this.statements != null) {
for (int i= 0; i < this.statements.length; i++) {
output.append('\n');
if (this.statements[i] instanceof CaseStatement) {
this.statements[i].printStatement(indent, output);
} else {
this.statements[i].printStatement(indent + 2, output);
}
}
}
output.append("\n"); //$NON-NLS-1$
return printIndent(indent, output).append('}');
}
public void resolve(BlockScope upperScope) {
try {
boolean isEnumSwitch= false;
TypeBinding expressionType= this.expression.resolveType(upperScope);
if (expressionType != null) {
this.expression.computeConversion(upperScope, expressionType, expressionType);
checkType: {
if (!expressionType.isValidBinding()) {
expressionType= null; // fault-tolerance: ignore type mismatch from constants from hereon
break checkType;
} else if (expressionType.isBaseType()) {
if (this.expression.isConstantValueOfTypeAssignableToType(expressionType, TypeBinding.INT))
break checkType;
if (expressionType.isCompatibleWith(TypeBinding.INT))
break checkType;
} else if (expressionType.isEnum()) {
isEnumSwitch= true;
break checkType;
} else if (upperScope.isBoxingCompatibleWith(expressionType, TypeBinding.INT)) {
this.expression.computeConversion(upperScope, TypeBinding.INT, expressionType);
break checkType;
}
upperScope.problemReporter().incorrectSwitchType(this.expression, expressionType);
expressionType= null; // fault-tolerance: ignore type mismatch from constants from hereon
}
}
if (this.statements != null) {
this.scope= /*explicitDeclarations == 0 ? upperScope : */new BlockScope(upperScope);
int length;
// collection of cases is too big but we will only iterate until caseCount
this.cases= new CaseStatement[length= this.statements.length];
this.constants= new int[length];
CaseStatement[] duplicateCaseStatements= null;
int duplicateCaseStatementsCounter= 0;
int counter= 0;
for (int i= 0; i < length; i++) {
Constant constant;
final Statement statement= this.statements[i];
if ((constant= statement.resolveCase(this.scope, expressionType, this)) != Constant.NotAConstant) {
int key= constant.intValue();
//----check for duplicate case statement------------
for (int j= 0; j < counter; j++) {
if (this.constants[j] == key) {
final CaseStatement currentCaseStatement= (CaseStatement)statement;
if (duplicateCaseStatements == null) {
this.scope.problemReporter().duplicateCase(this.cases[j]);
this.scope.problemReporter().duplicateCase(currentCaseStatement);
duplicateCaseStatements= new CaseStatement[length];
duplicateCaseStatements[duplicateCaseStatementsCounter++]= this.cases[j];
duplicateCaseStatements[duplicateCaseStatementsCounter++]= currentCaseStatement;
} else {
boolean found= false;
searchReportedDuplicate: for (int k= 2; k < duplicateCaseStatementsCounter; k++) {
if (duplicateCaseStatements[k] == statement) {
found= true;
break searchReportedDuplicate;
}
}
if (!found) {
this.scope.problemReporter().duplicateCase(currentCaseStatement);
duplicateCaseStatements[duplicateCaseStatementsCounter++]= currentCaseStatement;
}
}
}
}
this.constants[counter++]= key;
}
}
if (length != counter) { // resize constants array
System.arraycopy(this.constants, 0, this.constants= new int[counter], 0, counter);
}
} else {
if ((this.bits & UndocumentedEmptyBlock) != 0) {
upperScope.problemReporter().undocumentedEmptyBlock(this.blockStart, this.sourceEnd);
}
}
// for enum switch, check if all constants are accounted for (if no default)
if (isEnumSwitch && this.defaultCase == null
&& upperScope.compilerOptions().getSeverity(CompilerOptions.IncompleteEnumSwitch) != ProblemSeverities.Ignore) {
int constantCount= this.constants == null ? 0 : this.constants.length; // could be null if no case statement
if (constantCount == this.caseCount
&& this.caseCount != ((ReferenceBinding)expressionType).enumConstantCount()) {
FieldBinding[] enumFields= ((ReferenceBinding)expressionType.erasure()).fields();
for (int i= 0, max= enumFields.length; i < max; i++) {
FieldBinding enumConstant= enumFields[i];
if ((enumConstant.modifiers & ClassFileConstants.AccEnum) == 0)
continue;
findConstant: {
for (int j= 0; j < this.caseCount; j++) {
if ((enumConstant.id + 1) == this.constants[j]) // zero should not be returned see bug 141810
break findConstant;
}
// enum constant did not get referenced from switch
upperScope.problemReporter().missingEnumConstantCase(this, enumConstant);
}
}
}
}
} finally {
if (this.scope != null)
this.scope.enclosingCase= null; // no longer inside switch case block
}
}
public void traverse(
ASTVisitor visitor,
BlockScope blockScope) {
if (visitor.visit(this, blockScope)) {
this.expression.traverse(visitor, blockScope);
if (this.statements != null) {
int statementsLength= this.statements.length;
for (int i= 0; i < statementsLength; i++)
this.statements[i].traverse(visitor, this.scope);
}
}
visitor.endVisit(this, blockScope);
}
/**
* Dispatch the call on its last statement.
*/
public void branchChainTo(BranchLabel label) {
// in order to improve debug attributes for stepping (11431)
// we want to inline the jumps to #breakLabel which already got
// generated (if any), and have them directly branch to a better
// location (the argument label).
// we know at this point that the breakLabel already got placed
if (this.breakLabel.forwardReferenceCount() > 0) {
label.becomeDelegateFor(this.breakLabel);
}
}
}