+/*******************************************************************************
+ * 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;
-import java.util.List;
+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;
-/**
- * This is a if statement.
- * if (condition)
- * statement
- * (elseif statement)*
- * else statement
- * @author Matthieu Casanova
- */
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 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(final Expression condition,
- final Statement statement,
- final ElseIf[] elseifs,
- final Else els,
- final int sourceStart,
- final 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(final int tab) {
- final StringBuffer buff = new StringBuffer(tabString(tab));
- buff.append("if (");//$NON-NLS-1$
- buff.append(condition.toStringExpression()).append(") ");//$NON-NLS-1$
- if (statement != null) {
- buff.append(statement.toString(tab + 1));
- }
- for (int i = 0; i < elseifs.length; i++) {
- buff.append(elseifs[i].toString(tab + 1));
- buff.append("\n");//$NON-NLS-1$
- }
- if (els != null) {
- buff.append(els.toString(tab + 1));
- buff.append("\n");//$NON-NLS-1$
- }
- return buff.toString();
- }
-
- /**
- * Get the variables from outside (parameters, globals ...)
- */
- public void getOutsideVariable(final List list) {
- condition.getOutsideVariable(list); // todo: check if unuseful
- if (statement != null) {
- statement.getOutsideVariable(list);
- }
- for (int i = 0; i < elseifs.length; i++) {
- elseifs[i].getOutsideVariable(list);
- }
- if (els != null) {
- els.getOutsideVariable(list);
- }
- }
-
- /**
- * get the modified variables.
- */
- public void getModifiedVariable(final List list) {
- condition.getModifiedVariable(list);
- if (statement != null) {
- statement.getModifiedVariable(list);
- }
- for (int i = 0; i < elseifs.length; i++) {
- elseifs[i].getModifiedVariable(list);
- }
- if (els != null) {
- els.getModifiedVariable(list);
- }
- }
-
- /**
- * Get the variables used.
- */
- public void getUsedVariable(final List list) {
- condition.getUsedVariable(list);
- if (statement != null) {
- statement.getUsedVariable(list);
- }
- for (int i = 0; i < elseifs.length; i++) {
- elseifs[i].getUsedVariable(list);
- }
- if (els != null) {
- els.getUsedVariable(list);
- }
- }
+ 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);
+ }
}
git://secure.phpeclipse.com / phpeclipse.git / blobdiff