| /******************************************************************************* |
| * Copyright (c) 2000, 2003 IBM Corporation and others. |
| * All rights reserved. This program and the accompanying materials |
| * are made available under the terms of the Common Public License v1.0 |
| * which accompanies this distribution, and is available at |
| * http://www.eclipse.org/legal/cpl-v10.html |
| * |
| * Contributors: |
| * IBM Corporation - initial API and implementation |
| *******************************************************************************/ |
| package org.eclipse.jdt.internal.compiler.ast; |
| |
| import org.eclipse.jdt.internal.compiler.IAbstractSyntaxTreeVisitor; |
| import org.eclipse.jdt.internal.compiler.impl.*; |
| import org.eclipse.jdt.internal.compiler.codegen.*; |
| import org.eclipse.jdt.internal.compiler.flow.*; |
| import org.eclipse.jdt.internal.compiler.lookup.*; |
| |
| public class SwitchStatement extends Statement { |
| public Expression testExpression; |
| public Statement[] statements; |
| public BlockScope scope; |
| public int explicitDeclarations; |
| public Label breakLabel; |
| public Case[] cases; |
| public DefaultCase defaultCase; |
| public int caseCount = 0; |
| |
| // for local variables table attributes |
| int preSwitchInitStateIndex = -1; |
| int mergedInitStateIndex = -1; |
| /** |
| * SwitchStatement constructor comment. |
| */ |
| public SwitchStatement() { |
| super(); |
| } |
| public FlowInfo analyseCode( |
| BlockScope currentScope, |
| FlowContext flowContext, |
| FlowInfo flowInfo) { |
| flowInfo = testExpression.analyseCode(currentScope, flowContext, flowInfo); |
| SwitchFlowContext switchContext = |
| new SwitchFlowContext(flowContext, this, (breakLabel = new Label())); |
| |
| // 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 |
| preSwitchInitStateIndex = |
| currentScope.methodScope().recordInitializationStates(flowInfo); |
| int caseIndex = 0; |
| if (statements != null) { |
| boolean didAlreadyComplain = false; |
| for (int i = 0, max = statements.length; i < max; i++) { |
| Statement statement = statements[i]; |
| if ((caseIndex < caseCount) && (statement == cases[caseIndex])) { // statement is a case |
| caseIndex++; |
| caseInits = caseInits.mergedWith(flowInfo.copy().unconditionalInits()); |
| didAlreadyComplain = false; // reset complaint |
| } else if (statement == defaultCase) { // statement is the default case |
| caseInits = caseInits.mergedWith(flowInfo.copy().unconditionalInits()); |
| didAlreadyComplain = false; // reset complaint |
| } |
| if (!caseInits.complainIfUnreachable(statement, scope, didAlreadyComplain)) { |
| caseInits = statement.analyseCode(scope, switchContext, caseInits); |
| } else { |
| didAlreadyComplain = true; |
| } |
| } |
| } |
| |
| // if no default case, then record it may jump over the block directly to the end |
| if (defaultCase == null) { |
| // only retain the potential initializations |
| flowInfo.addPotentialInitializationsFrom( |
| caseInits.mergedWith(switchContext.initsOnBreak)); |
| mergedInitStateIndex = |
| currentScope.methodScope().recordInitializationStates(flowInfo); |
| return flowInfo; |
| } |
| |
| // merge all branches inits |
| FlowInfo mergedInfo = caseInits.mergedWith(switchContext.initsOnBreak); |
| mergedInitStateIndex = |
| currentScope.methodScope().recordInitializationStates(mergedInfo); |
| return mergedInfo; |
| } |
| /** |
| * 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) { |
| int[] sortedIndexes = new int[caseCount]; |
| int[] localKeysCopy; |
| if ((bits & IsReachableMASK) == 0) { |
| return; |
| } |
| int pc = codeStream.position; |
| |
| // prepare the labels and constants |
| breakLabel.codeStream = codeStream; |
| CaseLabel[] caseLabels = new CaseLabel[caseCount]; |
| int[] constants = new int[caseCount]; |
| boolean needSwitch = caseCount != 0; |
| for (int i = 0; i < caseCount; i++) { |
| constants[i] = cases[i].constantExpression.constant.intValue(); |
| cases[i].targetLabel = (caseLabels[i] = new CaseLabel(codeStream)); |
| } |
| |
| // we sort the keys to be able to generate the code for tableswitch or lookupswitch |
| for (int i = 0; i < caseCount; i++) { |
| sortedIndexes[i] = i; |
| } |
| System.arraycopy( |
| constants, |
| 0, |
| (localKeysCopy = new int[caseCount]), |
| 0, |
| caseCount); |
| CodeStream.sort(localKeysCopy, 0, caseCount - 1, sortedIndexes); |
| CaseLabel defaultLabel = new CaseLabel(codeStream); |
| if (defaultCase != null) { |
| defaultCase.targetLabel = defaultLabel; |
| } |
| // generate expression testes |
| testExpression.generateCode(currentScope, codeStream, needSwitch); |
| |
| // generate the appropriate switch table/lookup bytecode |
| if (needSwitch) { |
| int max = localKeysCopy[caseCount - 1]; |
| int min = localKeysCopy[0]; |
| if ((long) (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.environment().options.complianceLevel < CompilerOptions.JDK1_4) { |
| codeStream.lookupswitch(defaultLabel, constants, sortedIndexes, caseLabels); |
| |
| } else { |
| codeStream.tableswitch( |
| defaultLabel, |
| min, |
| max, |
| constants, |
| sortedIndexes, |
| caseLabels); |
| } |
| } else { |
| codeStream.lookupswitch(defaultLabel, constants, sortedIndexes, caseLabels); |
| } |
| codeStream.updateLastRecordedEndPC(codeStream.position); |
| } |
| |
| // generate the switch block statements |
| int caseIndex = 0; |
| if (statements != null) { |
| for (int i = 0, maxCases = statements.length; i < maxCases; i++) { |
| Statement statement = statements[i]; |
| if ((caseIndex < caseCount) |
| && (statement == cases[caseIndex])) { // statements[i] is a case |
| if (preSwitchInitStateIndex != -1) { |
| codeStream.removeNotDefinitelyAssignedVariables( |
| currentScope, |
| preSwitchInitStateIndex); |
| caseIndex++; |
| } |
| } else { |
| if (statement == defaultCase) { // statements[i] is a case or a default case |
| if (preSwitchInitStateIndex != -1) { |
| codeStream.removeNotDefinitelyAssignedVariables( |
| currentScope, |
| preSwitchInitStateIndex); |
| } |
| } |
| } |
| statement.generateCode(scope, codeStream); |
| } |
| } |
| // place the trailing labels (for break and default case) |
| breakLabel.place(); |
| if (defaultCase == null) { |
| defaultLabel.place(); |
| } |
| // May loose some local variable initializations : affecting the local variable attributes |
| if (mergedInitStateIndex != -1) { |
| codeStream.removeNotDefinitelyAssignedVariables( |
| currentScope, |
| mergedInitStateIndex); |
| codeStream.addDefinitelyAssignedVariables(currentScope, mergedInitStateIndex); |
| } |
| if (scope != currentScope) { |
| codeStream.exitUserScope(scope); |
| } |
| codeStream.recordPositionsFrom(pc, this.sourceStart); |
| } |
| |
| |
| public void resetStateForCodeGeneration() { |
| if (this.breakLabel != null) { |
| this.breakLabel.resetStateForCodeGeneration(); |
| } |
| } |
| |
| public void resolve(BlockScope upperScope) { |
| |
| TypeBinding testType = testExpression.resolveType(upperScope); |
| if (testType == null) |
| return; |
| testExpression.implicitWidening(testType, testType); |
| if (!(testExpression.isConstantValueOfTypeAssignableToType(testType, IntBinding))) { |
| if (!testType.isCompatibleWith(IntBinding)) { |
| upperScope.problemReporter().incorrectSwitchType(testExpression, testType); |
| return; |
| } |
| } |
| if (statements != null) { |
| scope = explicitDeclarations == 0 ? upperScope : new BlockScope(upperScope); |
| int length; |
| // collection of cases is too big but we will only iterate until caseCount |
| cases = new Case[length = statements.length]; |
| int[] casesValues = new int[length]; |
| int counter = 0; |
| for (int i = 0; i < length; i++) { |
| Constant cst; |
| if ((cst = statements[i].resolveCase(scope, testType, this)) != null) { |
| //----check for duplicate case statement------------ |
| if (cst != NotAConstant) { |
| int key = cst.intValue(); |
| for (int j = 0; j < counter; j++) { |
| if (casesValues[j] == key) { |
| scope.problemReporter().duplicateCase((Case) statements[i], cst); //TODO: (philippe) could improve diagnosis to indicate colliding case |
| } |
| } |
| casesValues[counter++] = key; |
| } |
| } |
| } |
| } |
| } |
| public String toString(int tab) { |
| |
| String inFront, s = tabString(tab); |
| inFront = s; |
| s = s + "switch (" + testExpression.toStringExpression() + ") "; //$NON-NLS-1$ //$NON-NLS-2$ |
| if (statements == null) { |
| s = s + "{}"; //$NON-NLS-1$ |
| return s; |
| } else |
| s = s + "{"; //$NON-NLS-1$ |
| s = s |
| + (explicitDeclarations != 0 |
| ? "// ---scope needed for " //$NON-NLS-1$ |
| + String.valueOf(explicitDeclarations) |
| + " locals------------ \n"//$NON-NLS-1$ |
| : "// ---NO scope needed------ \n"); //$NON-NLS-1$ |
| |
| int i = 0; |
| String tabulation = " "; //$NON-NLS-1$ |
| try { |
| while (true) { |
| //use instanceof in order not to polluate classes with behavior only needed for printing purpose. |
| if (statements[i] instanceof Expression) |
| s = s + "\n" + inFront + tabulation; //$NON-NLS-1$ |
| if (statements[i] instanceof Break) |
| s = s + statements[i].toString(0); |
| else |
| s = s + "\n" + statements[i].toString(tab + 2); //$NON-NLS-1$ |
| //============= |
| if ((statements[i] instanceof Case) |
| || (statements[i] instanceof DefaultCase)) { |
| i++; |
| while (!((statements[i] instanceof Case) |
| || (statements[i] instanceof DefaultCase))) { |
| if ((statements[i] instanceof Expression) || (statements[i] instanceof Break)) |
| s = s + statements[i].toString(0) + " ; "; //$NON-NLS-1$ |
| else |
| s = s + "\n" + statements[i].toString(tab + 6) + " ; "; //$NON-NLS-1$ //$NON-NLS-2$ |
| i++; |
| } |
| } else { |
| s = s + " ;"; //$NON-NLS-1$ |
| i++; |
| } |
| } |
| } catch (IndexOutOfBoundsException e) { |
| }; |
| s = s + "}"; //$NON-NLS-1$ |
| return s; |
| } |
| |
| public void traverse( |
| IAbstractSyntaxTreeVisitor visitor, |
| BlockScope blockScope) { |
| |
| if (visitor.visit(this, blockScope)) { |
| testExpression.traverse(visitor, scope); |
| if (statements != null) { |
| int statementsLength = statements.length; |
| for (int i = 0; i < statementsLength; i++) |
| statements[i].traverse(visitor, scope); |
| } |
| } |
| visitor.endVisit(this, blockScope); |
| } |
| |
| /** |
| * Dispatch the call on its last statement. |
| */ |
| public void branchChainTo(Label 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.hasForwardReferences()) { |
| label.appendForwardReferencesFrom(this.breakLabel); |
| } |
| } |
| } |
