--- /dev/null
+/*******************************************************************************
+ * Copyright (c) 2000, 2001, 2002 International Business Machines Corp. and others.
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Common Public License v0.5
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/legal/cpl-v05.html
+ *
+ * Contributors:
+ * IBM Corporation - initial API and implementation
+ ******************************************************************************/
+package net.sourceforge.phpdt.internal.compiler.ast;
+
+import net.sourceforge.phpdt.internal.compiler.IAbstractSyntaxTreeVisitor;
+import net.sourceforge.phpdt.internal.compiler.impl.*;
+import net.sourceforge.phpdt.internal.compiler.codegen.*;
+import net.sourceforge.phpdt.internal.compiler.flow.*;
+import net.sourceforge.phpdt.internal.compiler.lookup.*;
+
+public class IfStatement extends Statement {
+
+ //this class represents the case of only one statement in
+ //either else and/or then branches.
+
+ public Expression condition;
+ public Statement thenStatement;
+ public Statement elseStatement;
+
+ boolean thenExit;
+
+ // for local variables table attributes
+ int thenInitStateIndex = -1;
+ int elseInitStateIndex = -1;
+ int mergedInitStateIndex = -1;
+
+ public IfStatement(
+ Expression condition,
+ Statement thenStatement,
+ int s,
+ int e) {
+
+ this.condition = condition;
+ this.thenStatement = thenStatement;
+ sourceStart = s;
+ sourceEnd = e;
+ }
+
+ public IfStatement(
+ Expression condition,
+ Statement thenStatement,
+ Statement elseStatement,
+ int s,
+ int e) {
+
+ this.condition = condition;
+ this.thenStatement = thenStatement;
+ this.elseStatement = elseStatement;
+ sourceEnd = e;
+ sourceStart = s;
+ }
+
+ public FlowInfo analyseCode(
+ BlockScope currentScope,
+ FlowContext flowContext,
+ FlowInfo flowInfo) {
+
+ FlowInfo thenFlowInfo, elseFlowInfo;
+
+ // process the condition
+ flowInfo = condition.analyseCode(currentScope, flowContext, flowInfo);
+
+ // process the THEN part
+ if (thenStatement == null) {
+ thenFlowInfo = flowInfo.initsWhenTrue();
+ } else {
+ Constant cst;
+ thenFlowInfo =
+ ((((cst = condition.constant) != NotAConstant)
+ && (cst.booleanValue() == false))
+ || (((cst = condition.conditionalConstant()) != NotAConstant)
+ && (cst.booleanValue() == false)))
+ ? (flowInfo.initsWhenTrue().copy().markAsFakeReachable(true))
+ : flowInfo.initsWhenTrue().copy();
+ // Save info for code gen
+ thenInitStateIndex =
+ currentScope.methodScope().recordInitializationStates(thenFlowInfo);
+ if (!thenFlowInfo.complainIfUnreachable(thenStatement, currentScope)) {
+ thenFlowInfo =
+ thenStatement.analyseCode(currentScope, flowContext, thenFlowInfo);
+ }
+ };
+ // optimizing the jump around the ELSE part
+ thenExit = (thenFlowInfo == FlowInfo.DeadEnd) || thenFlowInfo.isFakeReachable();
+
+ // process the ELSE part
+ if (elseStatement == null) {
+ elseFlowInfo = flowInfo.initsWhenFalse();
+ } else {
+ Constant cst;
+ elseFlowInfo =
+ ((((cst = condition.constant) != NotAConstant) && (cst.booleanValue() == true))
+ || (((cst = condition.conditionalConstant()) != NotAConstant)
+ && (cst.booleanValue() == true)))
+ ? (flowInfo.initsWhenFalse().copy().markAsFakeReachable(true))
+ : flowInfo.initsWhenFalse().copy();
+ // Save info for code gen
+ elseInitStateIndex =
+ currentScope.methodScope().recordInitializationStates(elseFlowInfo);
+ if (!elseFlowInfo.complainIfUnreachable(elseStatement, currentScope)) {
+ elseFlowInfo =
+ elseStatement.analyseCode(currentScope, flowContext, elseFlowInfo);
+ }
+ }
+
+ // merge THEN & ELSE initializations
+ FlowInfo mergedInfo;
+ if ((condition.constant != NotAConstant)
+ && (condition.constant.booleanValue() == true)) {
+ // IF (TRUE)
+ if (thenExit) {
+ mergedInfo = elseFlowInfo.markAsFakeReachable(true);
+ mergedInitStateIndex =
+ currentScope.methodScope().recordInitializationStates(mergedInfo);
+ return mergedInfo;
+ } else {
+ mergedInitStateIndex =
+ currentScope.methodScope().recordInitializationStates(thenFlowInfo);
+ return thenFlowInfo;
+ }
+ } else {
+ // IF (FALSE)
+ if ((condition.constant != NotAConstant)
+ && (condition.constant.booleanValue() == false)) {
+ if (elseFlowInfo.isDeadEnd()) {
+ mergedInfo = thenFlowInfo.markAsFakeReachable(true);
+ mergedInitStateIndex =
+ currentScope.methodScope().recordInitializationStates(mergedInfo);
+ return mergedInfo;
+ } else {
+ mergedInitStateIndex =
+ currentScope.methodScope().recordInitializationStates(elseFlowInfo);
+ return elseFlowInfo;
+ }
+ }
+ }
+ mergedInfo = thenFlowInfo.mergedWith(elseFlowInfo.unconditionalInits());
+ mergedInitStateIndex =
+ currentScope.methodScope().recordInitializationStates(mergedInfo);
+ return mergedInfo;
+ }
+
+ /**
+ * If 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) {
+
+ if ((bits & IsReachableMASK) == 0) {
+ return;
+ }
+ int pc = codeStream.position;
+ Label endifLabel = new Label(codeStream);
+
+ // optimizing the then/else part code gen
+ Constant cst, condCst;
+ boolean hasThenPart =
+ !((((cst = condition.constant) != NotAConstant)
+ && (cst.booleanValue() == false))
+ || (thenStatement == null)
+ || (thenStatement.isEmptyBlock())
+ || (((condCst = condition.conditionalConstant()) != NotAConstant)
+ && (condCst.booleanValue() == false)));
+ boolean hasElsePart =
+ !(((cst != NotAConstant) && (cst.booleanValue() == true))
+ || (elseStatement == null)
+ || (elseStatement.isEmptyBlock())
+ || (((condCst = condition.conditionalConstant()) != NotAConstant)
+ && (condCst.booleanValue() == true)));
+
+ if (hasThenPart) {
+ Label falseLabel;
+ // generate boolean condition
+ condition.generateOptimizedBoolean(
+ currentScope,
+ codeStream,
+ null,
+ (falseLabel = new Label(codeStream)),
+ true);
+ // May loose some local variable initializations : affecting the local variable attributes
+ if (thenInitStateIndex != -1) {
+ codeStream.removeNotDefinitelyAssignedVariables(
+ currentScope,
+ thenInitStateIndex);
+ codeStream.addDefinitelyAssignedVariables(currentScope, thenInitStateIndex);
+ }
+ // generate then statement
+ thenStatement.generateCode(currentScope, codeStream);
+ // jump around the else statement
+ if (hasElsePart && !thenExit) {
+ thenStatement.branchChainTo(endifLabel);
+ int position = codeStream.position;
+ codeStream.goto_(endifLabel);
+ codeStream.updateLastRecordedEndPC(position);
+ //goto is tagged as part of the thenAction block
+ }
+ falseLabel.place();
+ } else {
+ if (hasElsePart) {
+ // generate boolean condition
+ condition.generateOptimizedBoolean(
+ currentScope,
+ codeStream,
+ endifLabel,
+ null,
+ true);
+ } else {
+ // generate condition side-effects
+ condition.generateCode(currentScope, codeStream, false);
+ codeStream.recordPositionsFrom(pc, this.sourceStart);
+ }
+ }
+ // generate else statement
+ if (hasElsePart) {
+ // May loose some local variable initializations : affecting the local variable attributes
+ if (elseInitStateIndex != -1) {
+ codeStream.removeNotDefinitelyAssignedVariables(
+ currentScope,
+ elseInitStateIndex);
+ codeStream.addDefinitelyAssignedVariables(currentScope, elseInitStateIndex);
+ }
+ elseStatement.generateCode(currentScope, codeStream);
+ }
+ endifLabel.place();
+ // May loose some local variable initializations : affecting the local variable attributes
+ if (mergedInitStateIndex != -1) {
+ codeStream.removeNotDefinitelyAssignedVariables(
+ currentScope,
+ mergedInitStateIndex);
+ }
+ codeStream.recordPositionsFrom(pc, this.sourceStart);
+ }
+
+ public void resolve(BlockScope scope) {
+
+ TypeBinding type = condition.resolveTypeExpecting(scope, BooleanBinding);
+ condition.implicitWidening(type, type);
+ if (thenStatement != null)
+ thenStatement.resolve(scope);
+ if (elseStatement != null)
+ elseStatement.resolve(scope);
+ }
+
+ public String toString(int tab) {
+
+ String inFront, s = tabString(tab);
+ inFront = s;
+ s = s + "if (" + condition.toStringExpression() + ") \n"; //$NON-NLS-1$ //$NON-NLS-2$
+ s = s + thenStatement.toString(tab + 2) + ";"; //$NON-NLS-1$
+ if (elseStatement != null)
+ s = s + "\n" + inFront + "else\n" + elseStatement.toString(tab + 2) + ";"; //$NON-NLS-2$ //$NON-NLS-1$ //$NON-NLS-3$
+ return s;
+ }
+
+ public void traverse(
+ IAbstractSyntaxTreeVisitor visitor,
+ BlockScope blockScope) {
+
+ if (visitor.visit(this, blockScope)) {
+ condition.traverse(visitor, blockScope);
+ if (thenStatement != null)
+ thenStatement.traverse(visitor, blockScope);
+ if (elseStatement != null)
+ elseStatement.traverse(visitor, blockScope);
+ }
+ visitor.endVisit(this, blockScope);
+ }
+}
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