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Eclipse Compiler for Java(TM)
/*******************************************************************************
* Copyright (c) 2000, 2021 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 - Contributions for
* bug 319201 - [null] no warning when unboxing SingleNameReference causes NPE
* bug 349326 - [1.7] new warning for missing try-with-resources
* bug 265744 - Enum switch should warn about missing default
* bug 374605 - Unreasonable warning for enum-based switch statements
* bug 345305 - [compiler][null] Compiler misidentifies a case of "variable can only be null"
*******************************************************************************/
package org.eclipse.jdt.internal.compiler.ast;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.function.Function;
import java.util.function.IntPredicate;
import org.eclipse.jdt.internal.compiler.ASTVisitor;
import org.eclipse.jdt.internal.compiler.ast.CaseStatement.ResolvedCase;
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.impl.JavaFeature;
import org.eclipse.jdt.internal.compiler.lookup.BlockScope;
import org.eclipse.jdt.internal.compiler.lookup.FieldBinding;
import org.eclipse.jdt.internal.compiler.lookup.LocalVariableBinding;
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.lookup.TypeIds;
import org.eclipse.jdt.internal.compiler.problem.ProblemSeverities;
@SuppressWarnings("rawtypes")
public class SwitchStatement extends Expression {
public Expression expression;
public Statement[] statements;
public BlockScope scope;
public int explicitDeclarations;
public BranchLabel breakLabel;
public CaseStatement[] cases;
public CaseStatement defaultCase;
public CaseStatement nullCase; // convenience pointer for pattern switches
public int blockStart;
public int caseCount;
int[] constants;
int[] constMapping;
// Any non int constants
public ResolvedCase[] otherConstants;
public int nConstants;
public int switchBits;
public boolean containsPatterns;
public boolean containsNull;
private BranchLabel switchPatternRestartTarget;
/* package */ Pattern totalPattern;
// fallthrough
public final static int CASE = 0;
public final static int FALLTHROUGH = 1;
public final static int ESCAPING = 2;
public final static int BREAKING = 3;
// Other bits
public final static int LabeledRules = ASTNode.Bit1;
public final static int NullCase = ASTNode.Bit2;
public final static int TotalPattern = ASTNode.Bit3;
public final static int Exhaustive = ASTNode.Bit4;
public final static int Enhanced = ASTNode.Bit5;
// for switch on strings
private static final char[] SecretStringVariableName = " switchDispatchString".toCharArray(); //$NON-NLS-1$
// for patterns in switch
/* package */ static final char[] SecretPatternVariableName = " switchDispatchPattern".toCharArray(); //$NON-NLS-1$
private static final char[] SecretPatternRestartIndexName = " switchPatternRestartIndex".toCharArray(); //$NON-NLS-1$
public SyntheticMethodBinding synthetic; // use for switch on enums types
// for local variables table attributes
int preSwitchInitStateIndex = -1;
int mergedInitStateIndex = -1;
Statement[] duplicateCases = null;
int duplicateCaseCounter = 0;
private LocalVariableBinding dispatchStringCopy = null;
private LocalVariableBinding dispatchPatternCopy = null;
private LocalVariableBinding restartIndexLocal = null;
/* package */ boolean isNonTraditional = false;
/* package */ List caseLabelElements = new ArrayList<>(0);//TODO: can we remove this?
public List caseLabelElementTypes = new ArrayList<>(0);
protected int getFallThroughState(Statement stmt, BlockScope blockScope) {
if ((this.switchBits & LabeledRules) != 0) {
if ((stmt instanceof Expression && ((Expression) stmt).isTrulyExpression()) || stmt instanceof ThrowStatement)
return BREAKING;
if (!stmt.canCompleteNormally())
return BREAKING;
if (stmt instanceof Block) {
Block block = (Block) stmt;
// Note implicit break anyway - Let the flow analysis do the dead code analysis
BreakStatement breakStatement = new BreakStatement(null, block.sourceEnd -1, block.sourceEnd);
breakStatement.isSynthetic = true; // suppress dead code flagging - codegen will not generate dead code anyway
int l = block.statements == null ? 0 : block.statements.length;
if (l == 0) {
block.statements = new Statement[] {breakStatement};
block.scope = this.scope; // (upper scope) see Block.resolve() for similar
} else {
Statement[] newArray = new Statement[l + 1];
System.arraycopy(block.statements, 0, newArray, 0, l);
newArray[l] = breakStatement;
block.statements = newArray;
}
return BREAKING;
}
}
return FALLTHROUGH;
}
protected void completeNormallyCheck(BlockScope blockScope) {
// do nothing
}
protected boolean needToCheckFlowInAbsenceOfDefaultBranch() {
return !this.isExhaustive();
}
@Override
public FlowInfo analyseCode(BlockScope currentScope, FlowContext flowContext, FlowInfo flowInfo) {
try {
flowInfo = this.expression.analyseCode(currentScope, flowContext, flowInfo);
if (isNullHostile()) {
this.expression.checkNPE(currentScope, flowContext, flowInfo, 1);
}
SwitchFlowContext switchContext =
new SwitchFlowContext(flowContext, this, (this.breakLabel = new BranchLabel()), true, true);
switchContext.isExpression = this instanceof SwitchExpression;
// 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) {
if (((CaseStatement) statement).containsPatternVariable())
this.scope.problemReporter().IllegalFallThroughToPattern(this.scope.enclosingCase);
else if ((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 = this.containsPatterns ? FALLTHROUGH : 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());
if ((this.switchBits & LabeledRules) != 0 && this.expression.resolvedType instanceof ReferenceBinding) {
if (this.expression instanceof NameReference) {
// default case does not apply to null => mark the variable being switched over as nonnull:
NameReference reference = (NameReference) this.expression;
if (reference.localVariableBinding() != null) {
caseInits.markAsDefinitelyNonNull(reference.localVariableBinding());
} else if (reference.lastFieldBinding() != null) {
if (this.scope.compilerOptions().enableSyntacticNullAnalysisForFields)
switchContext.recordNullCheckedFieldReference(reference, 2); // survive this case statement and into the next
}
} else if (this.expression instanceof FieldReference) {
if (this.scope.compilerOptions().enableSyntacticNullAnalysisForFields)
switchContext.recordNullCheckedFieldReference((FieldReference) this.expression, 2); // survive this case statement and into the next
}
}
complaintLevel = initialComplaintLevel; // reset complaint
fallThroughState = this.containsPatterns ? FALLTHROUGH : CASE;
} else {
if (!(this instanceof SwitchExpression) &&
currentScope.compilerOptions().complianceLevel >= ClassFileConstants.JDK14 &&
statement instanceof YieldStatement &&
((YieldStatement) statement).isImplicit) {
YieldStatement y = (YieldStatement) statement;
Expression e = ((YieldStatement) statement).expression;
/* JLS 13 14.11.2
Switch labeled rules in switch statements differ from those in switch expressions (15.28).
In switch statements they must be switch labeled statement expressions, ... */
if (!y.expression.statementExpression()) {
this.scope.problemReporter().invalidExpressionAsStatement(e);
}
}
fallThroughState = getFallThroughState(statement, currentScope); // reset below if needed
}
if ((complaintLevel = statement.complainIfUnreachable(caseInits, this.scope, complaintLevel, true)) < Statement.COMPLAINED_UNREACHABLE) {
caseInits = statement.analyseCode(this.scope, switchContext, caseInits);
if (caseInits == FlowInfo.DEAD_END) {
fallThroughState = ESCAPING;
}
switchContext.expireNullCheckedFieldInfo();
}
}
completeNormallyCheck(currentScope);
}
final TypeBinding resolvedTypeBinding = this.expression.resolvedType;
if (resolvedTypeBinding.isEnum()) {
final SourceTypeBinding sourceTypeBinding = currentScope.classScope().referenceContext.binding;
this.synthetic = sourceTypeBinding.addSyntheticMethodForSwitchEnum(resolvedTypeBinding, this);
}
// if no default case, then record it may jump over the block directly to the end
if (this.defaultCase == null && needToCheckFlowInAbsenceOfDefaultBranch()) {
// 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
}
}
private boolean isNullHostile() {
if ((this.expression.implicitConversion & TypeIds.UNBOXING) != 0) {
return true;
} else if (this.expression.resolvedType != null
&& (this.expression.resolvedType.id == T_JavaLangString || this.expression.resolvedType.isEnum())) {
return true;
} else if ((this.switchBits & (LabeledRules|NullCase)) == LabeledRules && this.totalPattern == null) {
return true;
}
return false;
}
/**
* Switch on String code generation
* This assumes that hashCode() specification for java.lang.String is API
* and is stable.
*
* @see "http://download.oracle.com/javase/6/docs/api/java/lang/String.html"
*
* @param currentScope org.eclipse.jdt.internal.compiler.lookup.BlockScope
* @param codeStream org.eclipse.jdt.internal.compiler.codegen.CodeStream
*/
public void generateCodeForStringSwitch(BlockScope currentScope, CodeStream codeStream) {
try {
if ((this.bits & IsReachable) == 0) {
return;
}
int pc = codeStream.position;
class StringSwitchCase implements Comparable {
int hashCode;
String string;
BranchLabel label;
public StringSwitchCase(int hashCode, String string, BranchLabel label) {
this.hashCode = hashCode;
this.string = string;
this.label = label;
}
@Override
public int compareTo(Object o) {
StringSwitchCase that = (StringSwitchCase) o;
if (this.hashCode == that.hashCode) {
return 0;
}
if (this.hashCode > that.hashCode) {
return 1;
}
return -1;
}
@Override
public String toString() {
return "StringSwitchCase :\n" + //$NON-NLS-1$
"case " + this.hashCode + ":(" + this.string + ")\n"; //$NON-NLS-1$ //$NON-NLS-2$ //$NON-NLS-3$
}
}
/*
* With multi constant case statements, the number of case statements (hence branch labels)
* and number of constants (hence hashcode labels) could be different. For e.g:
switch(s) {
case "FB", "c":
System.out.println("A/C");
break;
case "Ea":
System.out.println("B");
break;
With the above code, we will have
2 branch labels for FB and c
3 stringCases for FB, c and Ea
2 hashCodeCaseLabels one for FB, Ea and one for c
Should produce something like this:
lookupswitch { // 2
99: 32
2236: 44
default: 87
"FB" and "Ea" producing the same hashcode values, but still belonging in different case statements.
First, produce the two branch labels pertaining to the case statements
And the three string cases and use the this.constMapping to get the correct branch label.
*/
final boolean hasCases = this.caseCount != 0;
int constSize = hasCases ? this.otherConstants.length : 0;
BranchLabel[] sourceCaseLabels = this.gatherLabels(codeStream, new BranchLabel[this.nConstants], BranchLabel::new);
StringSwitchCase [] stringCases = new StringSwitchCase[constSize]; // may have to shrink later if multiple strings hash to same code.
CaseLabel [] hashCodeCaseLabels = new CaseLabel[constSize];
this.constants = new int[constSize]; // hashCode() values.
for (int i = 0; i < constSize; i++) {
String literal = this.otherConstants[i].c.stringValue();
stringCases[i] = new StringSwitchCase(literal.hashCode(), literal, sourceCaseLabels[this.constMapping[i]]);
hashCodeCaseLabels[i] = new CaseLabel(codeStream);
hashCodeCaseLabels[i].tagBits |= BranchLabel.USED;
}
Arrays.sort(stringCases);
int uniqHashCount = 0;
int lastHashCode = 0;
for (int i = 0, length = constSize; i < length; ++i) {
int hashCode = stringCases[i].hashCode;
if (i == 0 || hashCode != lastHashCode) {
lastHashCode = this.constants[uniqHashCount++] = hashCode;
}
}
if (uniqHashCount != constSize) { // multiple keys hashed to the same value.
System.arraycopy(this.constants, 0, this.constants = new int[uniqHashCount], 0, uniqHashCount);
System.arraycopy(hashCodeCaseLabels, 0, hashCodeCaseLabels = new CaseLabel[uniqHashCount], 0, uniqHashCount);
}
int[] sortedIndexes = new int[uniqHashCount]; // hash code are sorted already anyways.
for (int i = 0; i < uniqHashCount; i++) {
sortedIndexes[i] = i;
}
CaseLabel defaultCaseLabel = new CaseLabel(codeStream);
defaultCaseLabel.tagBits |= BranchLabel.USED;
// prepare the labels and constants
this.breakLabel.initialize(codeStream);
BranchLabel defaultBranchLabel = new BranchLabel(codeStream);
if (hasCases) defaultBranchLabel.tagBits |= BranchLabel.USED;
if (this.defaultCase != null) {
this.defaultCase.targetLabel = defaultBranchLabel;
}
// generate expression
this.expression.generateCode(currentScope, codeStream, true);
codeStream.store(this.dispatchStringCopy, true); // leaves string on operand stack
codeStream.addVariable(this.dispatchStringCopy);
codeStream.invokeStringHashCode();
if (hasCases) {
codeStream.lookupswitch(defaultCaseLabel, this.constants, sortedIndexes, hashCodeCaseLabels);
for (int i = 0, j = 0, max = constSize; i < max; i++) {
int hashCode = stringCases[i].hashCode;
if (i == 0 || hashCode != lastHashCode) {
lastHashCode = hashCode;
if (i != 0) {
codeStream.goto_(defaultBranchLabel);
}
hashCodeCaseLabels[j++].place();
}
codeStream.load(this.dispatchStringCopy);
codeStream.ldc(stringCases[i].string);
codeStream.invokeStringEquals();
codeStream.ifne(stringCases[i].label);
}
codeStream.goto_(defaultBranchLabel);
} else {
codeStream.pop();
}
// 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);
}
if (statement == this.defaultCase) { // statements[i] is a case or a default case
defaultCaseLabel.place(); // branch label gets placed by generateCode below.
}
caseIndex++;
} else {
if (statement == this.defaultCase) { // statements[i] is a case or a default case
defaultCaseLabel.place(); // branch label gets placed by generateCode below.
this.scope.enclosingCase = this.defaultCase; // record entering in a switch case block
if (this.preSwitchInitStateIndex != -1) {
codeStream.removeNotDefinitelyAssignedVariables(currentScope, this.preSwitchInitStateIndex);
}
}
}
statementGenerateCode(currentScope, codeStream, statement);
}
}
// 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);
}
codeStream.removeVariable(this.dispatchStringCopy);
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);
defaultCaseLabel.place();
defaultBranchLabel.place();
}
if (this.expectedType() != null) {
TypeBinding expectedType = this.expectedType().erasure();
boolean optimizedGoto = codeStream.lastAbruptCompletion == -1;
// if the last bytecode was an optimized goto (value is already on the stack) or an enum switch without default case, then we need to adjust the
// stack depth to reflect the fact that there is an value on the stack (return type of the switch expression)
codeStream.recordExpressionType(expectedType, optimizedGoto ? 0 : 1, optimizedGoto);
}
codeStream.recordPositionsFrom(pc, this.sourceStart);
} finally {
if (this.scope != null) this.scope.enclosingCase = null; // no longer inside switch case block
}
}
private T[] gatherLabels(CodeStream codeStream, T[] caseLabels,
Function newLabel)
{
for (int i = 0, j = 0, max = this.caseCount; i < max; i++) {
CaseStatement stmt = this.cases[i];
int l = stmt.constantExpressions.length;
BranchLabel[] targetLabels = new BranchLabel[l];
int count = 0;
for (int k = 0; k < l; ++k) {
Expression e = stmt.constantExpressions[k];
if (e instanceof FakeDefaultLiteral) continue;
targetLabels[count++] = (caseLabels[j] = newLabel.apply(codeStream));
if (e == this.totalPattern)
this.defaultCase = stmt;
caseLabels[j++].tagBits |= BranchLabel.USED;
}
System.arraycopy(targetLabels, 0, stmt.targetLabels = new BranchLabel[count], 0, count);
}
return caseLabels;
}
/**
* Switch 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.expression.resolvedType.id == TypeIds.T_JavaLangString && !this.isNonTraditional) {
generateCodeForStringSwitch(currentScope, codeStream);
return;
}
try {
if ((this.bits & IsReachable) == 0) {
return;
}
int pc = codeStream.position;
// prepare the labels and constants
this.breakLabel.initialize(codeStream);
int constantCount = this.otherConstants == null ? 0 : this.otherConstants.length;
CaseLabel[] caseLabels = this.gatherLabels(codeStream, new CaseLabel[this.nConstants], CaseLabel::new);
CaseLabel defaultLabel = new CaseLabel(codeStream);
final boolean hasCases = this.caseCount != 0;
if (hasCases) defaultLabel.tagBits |= BranchLabel.USED;
if (this.defaultCase != null) {
this.defaultCase.targetLabel = defaultLabel;
}
final TypeBinding resolvedType1 = this.expression.resolvedType;
boolean valueRequired = false;
if (this.containsPatterns) {
generateCodeSwitchPatternPrologue(currentScope, codeStream);
valueRequired = true;
} else if (resolvedType1.isEnum()) {
// 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(resolvedType1.constantPoolName());
codeStream.iaload();
if (!hasCases) {
// we can get rid of the generated ordinal value
codeStream.pop();
}
valueRequired = hasCases;
} else {
valueRequired = this.expression.constant == Constant.NotAConstant || hasCases;
// generate expression
this.expression.generateCode(currentScope, codeStream, valueRequired);
}
// generate the appropriate switch table/lookup bytecode
if (hasCases) {
int[] sortedIndexes = new int[constantCount];
// we sort the keys to be able to generate the code for tableswitch or lookupswitch
for (int i = 0; i < constantCount; i++) {
sortedIndexes[i] = i;
}
int[] localKeysCopy;
System.arraycopy(this.constants, 0, (localKeysCopy = new int[constantCount]), 0, constantCount);
CodeStream.sort(localKeysCopy, 0, constantCount - 1, sortedIndexes);
int max = localKeysCopy[constantCount - 1];
int min = localKeysCopy[0];
if ((long) (constantCount * 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,
this.constMapping,
caseLabels);
}
} else {
codeStream.lookupswitch(defaultLabel, this.constants, sortedIndexes, caseLabels);
}
codeStream.recordPositionsFrom(codeStream.position, this.expression.sourceEnd);
} else if (valueRequired) {
codeStream.pop();
}
// 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];
CaseStatement caseStatement = null;
if ((caseIndex < constantCount) && (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);
}
caseStatement = (CaseStatement) statement;
patternCaseExitPreviousCaseScope(codeStream, caseIndex);
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);
}
}
}
statementGenerateCode(currentScope, codeStream, statement);
generateCodePatternCaseEpilogue(codeStream, caseIndex, caseStatement);
}
}
boolean enumInSwitchExpression = resolvedType1.isEnum() && this instanceof SwitchExpression;
boolean isEnumSwitchWithoutDefaultCase = this.defaultCase == null && enumInSwitchExpression;
CompilerOptions compilerOptions = this.scope != null ? this.scope.compilerOptions() : null;
boolean isPatternSwitchSealedWithoutDefaultCase = this.defaultCase == null
&& compilerOptions != null
&& this.containsPatterns
&& JavaFeature.SEALED_CLASSES.isSupported(compilerOptions)
&& JavaFeature.PATTERN_MATCHING_IN_SWITCH.isSupported(compilerOptions)
&& this.expression.resolvedType instanceof ReferenceBinding
&& ((ReferenceBinding) this.expression.resolvedType).isSealed();
if (isEnumSwitchWithoutDefaultCase || isPatternSwitchSealedWithoutDefaultCase) {
// we want to force an line number entry to get an end position after the switch statement
if (this.preSwitchInitStateIndex != -1) {
codeStream.removeNotDefinitelyAssignedVariables(currentScope, this.preSwitchInitStateIndex);
}
defaultLabel.place();
/* a default case is not needed for enum if all enum values are used in the switch expression
* we need to handle the default case to throw an error (IncompatibleClassChangeError) in order
* to make the stack map consistent. All cases will return a value on the stack except the missing default
* case.
* There is no returned value for the default case so we handle it with an exception thrown. An
* IllegalClassChangeError seems legitimate as this would mean the enum type has been recompiled with more
* enum constants and the class that is using the switch on the enum has not been recompiled
*/
codeStream.newJavaLangIncompatibleClassChangeError();
codeStream.dup();
codeStream.invokeJavaLangIncompatibleClassChangeErrorDefaultConstructor();
codeStream.athrow();
}
// 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);
}
generateCodeSwitchPatternEpilogue(codeStream);
if (this.scope != currentScope) {
codeStream.exitUserScope(this.scope);
}
// place the trailing labels (for break and default case)
this.breakLabel.place();
if (this.defaultCase == null && !(enumInSwitchExpression || isPatternSwitchSealedWithoutDefaultCase)) {
// 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();
}
if (this instanceof SwitchExpression) {
TypeBinding switchResolveType = this.resolvedType;
if (this.expectedType() != null) {
switchResolveType = this.expectedType().erasure();
}
boolean optimizedGoto = codeStream.lastAbruptCompletion == -1;
// if the last bytecode was an optimized goto (value is already on the stack) or an enum switch without default case, then we need to adjust the
// stack depth to reflect the fact that there is an value on the stack (return type of the switch expression)
codeStream.recordExpressionType(switchResolveType, optimizedGoto ? 0 : 1, optimizedGoto || isEnumSwitchWithoutDefaultCase);
}
codeStream.recordPositionsFrom(pc, this.sourceStart);
} finally {
if (this.scope != null) this.scope.enclosingCase = null; // no longer inside switch case block
}
}
private void generateCodeSwitchPatternEpilogue(CodeStream codeStream) {
if (this.containsPatterns && this.caseLabelElements.size() > 0) {
codeStream.removeVariable(this.dispatchPatternCopy);
codeStream.removeVariable(this.restartIndexLocal);
}
}
private void patternCaseExitPreviousCaseScope(CodeStream codeStream, int caseIndex) {
if (caseIndex > 0) {
CaseStatement caseStatement = this.cases[caseIndex];
if (caseStatement.containsPatternVariable()) {
caseStatement.patternCaseRemovePatternLocals(codeStream);
}
}
}
private void generateCodePatternCaseEpilogue(CodeStream codeStream, int caseIndex, CaseStatement caseStatement) {
if (this.switchPatternRestartTarget != null && caseStatement != null
&& caseStatement.patternIndex != -1 // for null
) {
Pattern pattern = (Pattern) caseStatement.constantExpressions[caseStatement.patternIndex];
if (pattern instanceof GuardedPattern) {
codeStream.loadInt(caseIndex);
codeStream.store(this.restartIndexLocal, false);
codeStream.goto_(this.switchPatternRestartTarget);
((GuardedPattern) pattern).thenTarget.place();
}
}
}
private void generateCodeSwitchPatternPrologue(BlockScope currentScope, CodeStream codeStream) {
this.expression.generateCode(currentScope, codeStream, true);
if ((this.switchBits & NullCase) == 0 && this.totalPattern == null) {
codeStream.dup();
codeStream.invokeJavaUtilObjectsrequireNonNull();
codeStream.pop();
}
codeStream.store(this.dispatchPatternCopy, false);
codeStream.addVariable(this.dispatchPatternCopy);
int restartIndex = 0;
codeStream.loadInt(restartIndex);
codeStream.store(this.restartIndexLocal, false);
codeStream.addVariable(this.restartIndexLocal);
this.switchPatternRestartTarget = new BranchLabel(codeStream);
this.switchPatternRestartTarget.place();
codeStream.load(this.dispatchPatternCopy);
codeStream.load(this.restartIndexLocal);
int invokeDynamicNumber = codeStream.classFile.recordBootstrapMethod(this);
codeStream.invokeDynamic(invokeDynamicNumber,
2, // Object, restartIndex
1, // int
"typeSwitch".toCharArray(), //$NON-NLS-1$
"(Ljava/lang/Object;I)I".toCharArray(), //$NON-NLS-1$
TypeIds.T_int,
TypeBinding.INT);
}
protected void statementGenerateCode(BlockScope currentScope, CodeStream codeStream, Statement statement) {
statement.generateCode(this.scope, codeStream);
}
@Override
public void generateCode(BlockScope currentScope, CodeStream codeStream, boolean valueRequired) {
generateCode(currentScope, codeStream); // redirecting to statement part
}
@Override
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('}');
}
private int getNConstants() {
int n = 0;
for (int i = 0, l = this.statements.length; i < l; ++i) {
final Statement statement = this.statements[i];
if (statement instanceof CaseStatement) {
Expression[] exprs = ((CaseStatement) statement).constantExpressions;
int count = 0;
if (exprs != null) {
for (Expression e : exprs) {
if (e instanceof FakeDefaultLiteral) continue;
++count;
}
}
n += count;
}
}
return n;
}
protected void addSecretTryResultVariable() {
// do nothing
}
/* package */ boolean isAllowedType(TypeBinding type) {
if (type == null)
return false;
switch (type.id) {
case TypeIds.T_char:
case TypeIds.T_byte:
case TypeIds.T_short:
case TypeIds.T_int:
case TypeIds.T_JavaLangCharacter :
case TypeIds.T_JavaLangByte :
case TypeIds.T_JavaLangShort :
case TypeIds.T_JavaLangInteger :
return true;
default: break;
}
return false;
}
@Override
public void resolve(BlockScope upperScope) {
try {
boolean isEnumSwitch = false;
boolean isStringSwitch = false;
TypeBinding expressionType = this.expression.resolveType(upperScope);
CompilerOptions compilerOptions = upperScope.compilerOptions();
boolean isEnhanced = checkAndSetEnhanced(upperScope, expressionType);
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;
if (compilerOptions.complianceLevel < ClassFileConstants.JDK1_5) {
upperScope.problemReporter().incorrectSwitchType(this.expression, expressionType); // https://bugs.eclipse.org/bugs/show_bug.cgi?id=360317
}
break checkType;
} else if (!this.containsPatterns && upperScope.isBoxingCompatibleWith(expressionType, TypeBinding.INT)) {
this.expression.computeConversion(upperScope, TypeBinding.INT, expressionType);
break checkType;
} else if (compilerOptions.complianceLevel >= ClassFileConstants.JDK1_7 && expressionType.id == TypeIds.T_JavaLangString) {
if (this.containsPatterns) {
isStringSwitch = !JavaFeature.PATTERN_MATCHING_IN_SWITCH.isSupported(compilerOptions);
this.isNonTraditional = true;
break checkType;
}
isStringSwitch = true;
break checkType;
}
if (!JavaFeature.PATTERN_MATCHING_IN_SWITCH.isSupported(compilerOptions)) {
upperScope.problemReporter().incorrectSwitchType(this.expression, expressionType);
expressionType = null; // fault-tolerance: ignore type mismatch from constants from hereon
} else {
this.isNonTraditional = true;
}
}
}
if (isStringSwitch) {
// the secret variable should be created before iterating over the switch's statements that could
// create more locals. This must be done to prevent overlapping of locals
// See https://bugs.eclipse.org/bugs/show_bug.cgi?id=356002
this.dispatchStringCopy = new LocalVariableBinding(SecretStringVariableName, upperScope.getJavaLangString(), ClassFileConstants.AccDefault, false);
upperScope.addLocalVariable(this.dispatchStringCopy);
this.dispatchStringCopy.setConstant(Constant.NotAConstant);
this.dispatchStringCopy.useFlag = LocalVariableBinding.USED;
}
addSecretPatternSwitchVariables(upperScope);
if (this.statements != null) {
if (this.scope == null)
this.scope = 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.nConstants = getNConstants();
this.constants = new int[this.nConstants];
this.otherConstants = new ResolvedCase[this.nConstants];
this.constMapping = new int[this.nConstants];
int counter = 0;
int caseCounter = 0;
Pattern[] patterns = new Pattern[this.nConstants];
int[] caseIndex = new int[this.nConstants];
LocalVariableBinding[] patternVariables = null;
for (int i = 0; i < length; i++) {
ResolvedCase[] constantsList;
final Statement statement = this.statements[i];
// Let's first collect the pattern variables if any
// so that we can resolve all statements (including case statements)
// with the pattern variables in scope.
if (statement instanceof CaseStatement) {
if (statement.containsPatternVariable()) {
((CaseStatement) statement).collectPatternVariablesToScope(null, this.scope);
patternVariables = statement.getPatternVariablesWhenTrue();
} else {
patternVariables = null; // Probably redundant?
}
} else {
statement.resolveWithPatternVariablesInScope(patternVariables, this.scope);
continue;
}
CaseStatement caseStmt = (CaseStatement) statement;
constantsList = caseStmt.resolveCase(this.scope, expressionType, this);
if (constantsList != ResolvedCase.UnresolvedCase) {
for (ResolvedCase c : constantsList) {
Constant con = c.c;
if (con == Constant.NotAConstant)
continue;
this.otherConstants[counter] = c;
final int c1 = this.containsPatterns ? (c.intValue() == -1 ? -1 : counter) : c.intValue();
this.constants[counter] = c1;
for (int j = 0; j < counter; j++) {
IntPredicate check = (idx) -> {
Constant c2 = this.otherConstants[idx].c;
if (con.typeID() == TypeIds.T_JavaLangString) {
return c2.stringValue().equals(con.stringValue());
} else {
return (c2.typeID() == TypeIds.T_JavaLangString) ? false : c2.intValue() == c1;
}
};
TypeBinding type = c.e.resolvedType;
if (!type.isValidBinding())
continue;
Pattern p1 = patterns[j];
if (p1 != null) {
if (c.isPattern()) {
if (p1.dominates((Pattern) c.e)) {
this.scope.problemReporter().patternDominatedByAnother(c.e);
}
} else {
if (type.id != TypeIds.T_null) {
if (type.isBaseType()) {
type = this.scope.environment().computeBoxingType(type);
}
if (p1.isTotalForType(type))
this.scope.problemReporter().patternDominatedByAnother(c.e);
}
}
} else {
if (!c.isPattern() && check.test(j)) {
if (this.isNonTraditional) {
reportDuplicateCase(c.e, this.otherConstants[j].e, length);
} else {
reportDuplicateCase(caseStmt, this.cases[caseIndex[j]], length);
}
}
}
}
this.constMapping[counter] = counter;
caseIndex[counter] = caseCounter;
// Only the pattern expressions count for dominance check
if (c.e instanceof Pattern) {
patterns[counter] = (Pattern) c.e;
}
counter++;
}
}
caseCounter++;
}
if (length != counter) { // resize constants array
System.arraycopy(this.otherConstants, 0, this.otherConstants = new ResolvedCase[counter], 0, counter);
System.arraycopy(this.constants, 0, this.constants = new int[counter], 0, counter);
System.arraycopy(this.constMapping, 0, this.constMapping = new int[counter], 0, counter);
}
} else {
if ((this.bits & UndocumentedEmptyBlock) != 0) {
upperScope.problemReporter().undocumentedEmptyBlock(this.blockStart, this.sourceEnd);
}
}
reportMixingCaseTypes();
// check default case for all kinds of switch:
checkAndFlagDefaultSealed(upperScope, compilerOptions);
if (this.defaultCase == null) {
if (ignoreMissingDefaultCase(compilerOptions, isEnumSwitch) && isEnumSwitch) {
upperScope.methodScope().hasMissingSwitchDefault = true;
} else {
if (!isExhaustive()) {
if (isEnhanced)
upperScope.problemReporter().enhancedSwitchMissingDefaultCase(this.expression);
else
upperScope.problemReporter().missingDefaultCase(this, isEnumSwitch, expressionType);
}
}
}
// for enum switch, check if all constants are accounted for (perhaps depending on existence of a default case)
if (isEnumSwitch && compilerOptions.complianceLevel >= ClassFileConstants.JDK1_5) {
if (this.defaultCase == null || compilerOptions.reportMissingEnumCaseDespiteDefault) {
int constantCount = this.otherConstants == null ? 0 : this.otherConstants.length; // could be null if no case statement
// The previous computation of exhaustiveness by comparing the size of cases to the enum fields
// no longer holds true when we throw in a pattern expression to the mix.
// And if there is a total pattern, then we don't have to check further.
if (!((this.switchBits & TotalPattern) != 0) &&
(this.containsPatterns ||
(constantCount >= this.caseCount &&
constantCount != ((ReferenceBinding)expressionType).enumConstantCount()))) {
FieldBinding[] enumFields = ((ReferenceBinding)expressionType.erasure()).fields();
for (int i = 0, max = enumFields.length; i permittedTypes = Arrays.asList(ref.permittedTypes());
for (TypeBinding pt : permittedTypes) {
if (!this.caseLabelElementTypes.contains(pt)) {
skope.problemReporter().missingDefaultCase(this, false, ref);
return;
}
}
this.switchBits |= SwitchStatement.Exhaustive;
}
private void addSecretPatternSwitchVariables(BlockScope upperScope) {
if (this.containsPatterns) {
this.scope = new BlockScope(upperScope);
this.dispatchPatternCopy = new LocalVariableBinding(SecretPatternVariableName, this.expression.resolvedType, ClassFileConstants.AccDefault, false);
this.scope.addLocalVariable(this.dispatchPatternCopy);
this.dispatchPatternCopy.setConstant(Constant.NotAConstant);
this.dispatchPatternCopy.useFlag = LocalVariableBinding.USED;
this.restartIndexLocal = new LocalVariableBinding(SecretPatternRestartIndexName, TypeBinding.INT, ClassFileConstants.AccDefault, false);
this.scope.addLocalVariable(this.restartIndexLocal);
this.restartIndexLocal.setConstant(Constant.NotAConstant);
this.restartIndexLocal.useFlag = LocalVariableBinding.USED;
}
}
protected void reportMissingEnumConstantCase(BlockScope upperScope, FieldBinding enumConstant) {
upperScope.problemReporter().missingEnumConstantCase(this, enumConstant);
}
protected boolean ignoreMissingDefaultCase(CompilerOptions compilerOptions, boolean isEnumSwitch) {
return compilerOptions.getSeverity(CompilerOptions.MissingDefaultCase) == ProblemSeverities.Ignore;
}
@Override
public boolean isTrulyExpression() {
return false;
}
private void reportMixingCaseTypes() {
if (this.caseCount == 0) {
if (this.defaultCase != null && this.defaultCase.isExpr)
this.switchBits |= LabeledRules;
return;
}
if (this.cases[0] == null)
return;
boolean isExpr = this.cases[0].isExpr;
if (isExpr) this.switchBits |= LabeledRules;
for (int i = 1, l = this.caseCount; i < l; ++i) {
if (this.cases[i].isExpr != isExpr) {
this.scope.problemReporter().switchExpressionMixedCase(this.cases[i]);
return;
}
}
if (this.defaultCase != null && this.defaultCase.isExpr != isExpr) {
this.scope.problemReporter().switchExpressionMixedCase(this.defaultCase);
}
}
private void reportDuplicateCase(final Statement duplicate,
final Statement original,
int length) {
if (this.duplicateCases == null) {
this.scope.problemReporter().duplicateCase(original);
if (duplicate != original)
this.scope.problemReporter().duplicateCase(duplicate);
this.duplicateCases = new Statement[length];
this.duplicateCases[this.duplicateCaseCounter++] = original;
if (duplicate != original)
this.duplicateCases[this.duplicateCaseCounter++] = duplicate;
} else {
boolean found = false;
searchReportedDuplicate: for (int k = 2; k < this.duplicateCaseCounter; k++) {
if (this.duplicateCases[k] == duplicate) {
found = true;
break searchReportedDuplicate;
}
}
if (!found) {
this.scope.problemReporter().duplicateCase(duplicate);
this.duplicateCases[this.duplicateCaseCounter++] = duplicate;
}
}
}
@Override
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.
*/
@Override
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);
}
}
@Override
public boolean doesNotCompleteNormally() {
if (this.statements == null || this.statements.length == 0)
return false;
for (int i = 0, length = this.statements.length; i < length; i++) {
if (this.statements[i].breaksOut(null))
return false;
}
return this.statements[this.statements.length - 1].doesNotCompleteNormally();
}
@Override
public boolean completesByContinue() {
if (this.statements == null || this.statements.length == 0)
return false;
for (int i = 0, length = this.statements.length; i < length; i++) {
if (this.statements[i].completesByContinue())
return true;
}
return false;
}
@Override
public boolean canCompleteNormally() {
if (this.statements == null || this.statements.length == 0)
return true;
if ((this.switchBits & LabeledRules) == 0) { // switch labeled statement group
if (this.statements[this.statements.length - 1].canCompleteNormally())
return true; // last statement as well as last switch label after blocks if exists.
if (this.defaultCase == null)
return true;
for (int i = 0, length = this.statements.length; i < length; i++) {
if (this.statements[i].breaksOut(null))
return true;
}
} else {
// switch block consists of switch rules
for (Statement stmt : this.statements) {
if (stmt instanceof CaseStatement)
continue; // skip case
if (this.defaultCase == null)
return true;
if (stmt instanceof Expression)
return true;
if (stmt.canCompleteNormally())
return true;
if (stmt instanceof YieldStatement && ((YieldStatement) stmt).isImplicit) // note: artificially introduced
return true;
if (stmt instanceof Block) {
Block block = (Block) stmt;
if (block.canCompleteNormally())
return true;
if (block.breaksOut(null))
return true;
}
}
}
return false;
}
@Override
public boolean continueCompletes() {
if (this.statements == null || this.statements.length == 0)
return false;
for (int i = 0, length = this.statements.length; i < length; i++) {
if (this.statements[i].continueCompletes())
return true;
}
return false;
}
@Override
public StringBuffer printExpression(int indent, StringBuffer output) {
return printStatement(indent, output);
}
}