+/*******************************************************************************
+ * 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 net.sourceforge.phpdt.internal.compiler.ast;
-/**
- * This is a if statement.
- * if (condition)
- * statement
- * (elseif statement)*
- * else statement
- * @author Matthieu Casanova
- */
+import net.sourceforge.phpdt.internal.compiler.ASTVisitor;
+import net.sourceforge.phpdt.internal.compiler.flow.FlowContext;
+import net.sourceforge.phpdt.internal.compiler.flow.FlowInfo;
+import net.sourceforge.phpdt.internal.compiler.impl.Constant;
+import net.sourceforge.phpdt.internal.compiler.lookup.BlockScope;
+import net.sourceforge.phpdt.internal.compiler.lookup.TypeBinding;
+
public class IfStatement extends Statement {
- public Expression condition;
- public Statement statement;
- public ElseIf[] elseifs;
- public Else els;
-
- /**
- * Create a new If statement.
- * @param condition the condition
- * @param statement a statement or a block of statements
- * @param elseifs the elseifs
- * @param els the else (or null)
- * @param sourceStart the starting position
- * @param sourceEnd the ending offset
- */
- public IfStatement(Expression condition,
- Statement statement,
- ElseIf[] elseifs,
- Else els,
- int sourceStart,
- int sourceEnd) {
- super(sourceStart, sourceEnd);
- this.condition = condition;
- this.statement = statement;
- this.elseifs = elseifs;
- this.els = els;
- }
-
- /**
- * Return the object into String.
- * @param tab how many tabs (not used here
- * @return a String
- */
- public String toString(int tab) {
- final StringBuffer buff = new StringBuffer(tabString(tab));
- buff.append("if (");
- buff.append(condition.toStringExpression()).append(") ");
- buff.append(statement.toString(tab+1));
- for (int i = 0; i < elseifs.length; i++) {
- buff.append(elseifs[i].toString(tab+1));
- buff.append("\n");
- }
- if (els != null) {
- buff.append(els.toString(tab+1));
- buff.append('\n');
- }
- return buff.toString();
- }
+ // 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;
+
+ public Expression[] elseifConditions;
+
+ public Statement[] elseifStatements;
+
+ public boolean checkUnreachable;
+
+ 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;
+ checkUnreachable = true;
+ }
+
+ 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;
+ checkUnreachable = true;
+ }
+
+ public FlowInfo analyseCode(BlockScope currentScope,
+ FlowContext flowContext, FlowInfo flowInfo) {
+
+ // process the condition
+ flowInfo = condition.analyseCode(currentScope, flowContext, flowInfo);
+
+ Constant cst = this.condition.optimizedBooleanConstant();
+ boolean isConditionOptimizedTrue = cst != NotAConstant
+ && cst.booleanValue() == true;
+ boolean isConditionOptimizedFalse = cst != NotAConstant
+ && cst.booleanValue() == false;
+
+ // process the THEN part
+ FlowInfo thenFlowInfo = flowInfo.initsWhenTrue().copy();
+ if (isConditionOptimizedFalse) {
+ thenFlowInfo.setReachMode(FlowInfo.UNREACHABLE);
+ }
+ if (this.thenStatement != null) {
+ // Save info for code gen
+ thenInitStateIndex = currentScope.methodScope()
+ .recordInitializationStates(thenFlowInfo);
+ if (!thenFlowInfo.complainIfUnreachable(thenStatement,
+ currentScope, false)) {
+ thenFlowInfo = thenStatement.analyseCode(currentScope,
+ flowContext, thenFlowInfo);
+ }
+ }
+ ;
+ // optimizing the jump around the ELSE part
+ this.thenExit = !thenFlowInfo.isReachable();
+
+ // process the ELSE part
+ FlowInfo elseFlowInfo = flowInfo.initsWhenFalse().copy();
+ if (isConditionOptimizedTrue) {
+ elseFlowInfo.setReachMode(FlowInfo.UNREACHABLE);
+ }
+ if (this.elseStatement != null) {
+ // Save info for code gen
+ elseInitStateIndex = currentScope.methodScope()
+ .recordInitializationStates(elseFlowInfo);
+ if (!elseFlowInfo.complainIfUnreachable(elseStatement,
+ currentScope, false)) {
+ elseFlowInfo = elseStatement.analyseCode(currentScope,
+ flowContext, elseFlowInfo);
+ }
+ }
+
+ boolean elseExit = !elseFlowInfo.isReachable();
+
+ // merge THEN & ELSE initializations
+ FlowInfo mergedInfo;
+ // if (isConditionOptimizedTrue){
+ // if (!this.thenExit) {
+ // mergedInfo = thenFlowInfo;
+ // } else {
+ // mergedInfo = elseFlowInfo.setReachMode(FlowInfo.UNREACHABLE);
+ // }
+ //
+ // } else if (isConditionOptimizedFalse) {
+ // if (!elseExit) {
+ // mergedInfo = elseFlowInfo;
+ // } else {
+ // mergedInfo = thenFlowInfo.setReachMode(FlowInfo.UNREACHABLE);
+ // }
+ //
+ // } else {
+ // mergedInfo =
+ // thenFlowInfo.mergedWith(elseFlowInfo.unconditionalInits());
+ // }
+ if (isConditionOptimizedTrue) {
+ if (!this.thenExit) {
+ mergedInfo = thenFlowInfo
+ .addPotentialInitializationsFrom(elseFlowInfo);
+ } else {
+ mergedInfo = elseFlowInfo.setReachMode(FlowInfo.UNREACHABLE);
+ }
+
+ } else if (isConditionOptimizedFalse) {
+ if (!elseExit) {
+ mergedInfo = elseFlowInfo
+ .addPotentialInitializationsFrom(thenFlowInfo);
+ } else {
+ mergedInfo = thenFlowInfo.setReachMode(FlowInfo.UNREACHABLE);
+ }
+
+ } else {
+ mergedInfo = thenFlowInfo.mergedWith(elseFlowInfo
+ .unconditionalInits());
+ }
+
+ mergedInitStateIndex = currentScope.methodScope()
+ .recordInitializationStates(mergedInfo);
+ return mergedInfo;
+ }
+
+ /**
+ * If code generation
+ *
+ * @param currentScope
+ * net.sourceforge.phpdt.internal.compiler.lookup.BlockScope
+ * @param codeStream
+ * net.sourceforge.phpdt.internal.compiler.codegen.CodeStream
+ */
+ // public void generateCode(BlockScope currentScope, CodeStream codeStream)
+ // {
+ //
+ // if ((this.bits & IsReachableMASK) == 0) {
+ // return;
+ // }
+ // int pc = codeStream.position;
+ // Label endifLabel = new Label(codeStream);
+ //
+ // // optimizing the then/else part code gen
+ // Constant cst;
+ // boolean hasThenPart =
+ // !(((cst = this.condition.optimizedBooleanConstant()) != NotAConstant
+ // && cst.booleanValue() == false)
+ // || this.thenStatement == null
+ // || this.thenStatement.isEmptyBlock());
+ // boolean hasElsePart =
+ // !((cst != NotAConstant && cst.booleanValue() == true)
+ // || this.elseStatement == null
+ // || this.elseStatement.isEmptyBlock());
+ //
+ // if (hasThenPart) {
+ // Label falseLabel;
+ // // generate boolean condition
+ // this.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
+ // this.thenStatement.generateCode(currentScope, codeStream);
+ // // jump around the else statement
+ // if (hasElsePart && !thenExit) {
+ // this.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
+ // this.condition.generateOptimizedBoolean(
+ // currentScope,
+ // codeStream,
+ // endifLabel,
+ // null,
+ // true);
+ // } else {
+ // // generate condition side-effects
+ // this.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);
+ // }
+ // this.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 StringBuffer printStatement(int indent, StringBuffer output) {
+
+ printIndent(indent, output).append("if ("); //$NON-NLS-1$
+ condition.printExpression(0, output).append(")\n"); //$NON-NLS-1$
+ thenStatement.printStatement(indent + 2, output);
+ if (elseStatement != null) {
+ output.append('\n');
+ printIndent(indent, output);
+ output.append("else\n"); //$NON-NLS-1$
+ elseStatement.printStatement(indent + 2, output);
+ }
+ return output;
+ }
+
+ 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(ASTVisitor 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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