+/*******************************************************************************
+ * 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 java.util.ArrayList;
+import net.sourceforge.phpdt.internal.compiler.ASTVisitor;
+import net.sourceforge.phpdt.internal.compiler.codegen.Label;
+import net.sourceforge.phpdt.internal.compiler.flow.FlowContext;
+import net.sourceforge.phpdt.internal.compiler.flow.FlowInfo;
+import net.sourceforge.phpdt.internal.compiler.flow.LoopingFlowContext;
+import net.sourceforge.phpdt.internal.compiler.impl.Constant;
+import net.sourceforge.phpdt.internal.compiler.lookup.BlockScope;
+import net.sourceforge.phpdt.internal.compiler.lookup.TypeBinding;
-/**
- * A While statement.
- * @author Matthieu Casanova
- */
public class WhileStatement extends Statement {
- /** The condition expression. */
- public Expression condition;
- /** The action of the while. (it could be a block) */
- public Statement action;
-
- /**
- * Create a While statement.
- * @param condition the condition
- * @param action the action
- * @param sourceStart the starting offset
- * @param sourceEnd the ending offset
- */
- public WhileStatement(final Expression condition,
- final Statement action,
- final int sourceStart,
- final int sourceEnd) {
- super(sourceStart, sourceEnd);
- this.condition = condition;
- this.action = action;
- }
-
- /**
- * Return the object into String.
- * @param tab how many tabs (not used here
- * @return a String
- */
- public String toString(final int tab) {
- final String s = tabString(tab);
- final StringBuffer buff = new StringBuffer(s).append("while ("); //$NON-NLS-1$
- buff.append(condition.toStringExpression()).append(")"); //$NON-NLS-1$
- if (action == null) {
- buff.append(" {} ;"); //$NON-NLS-1$
- } else {
- buff.append("\n").append(action.toString(tab + 1)); //$NON-NLS-1$
- }
- return buff.toString();
- }
-
- /**
- * Get the variables from outside (parameters, globals ...)
- */
- public void getOutsideVariable(final List list) {
- condition.getOutsideVariable(list); // todo: check if unuseful
- if (action != null) {
- action.getOutsideVariable(list);
- }
- }
-
- /**
- * get the modified variables.
- */
- public void getModifiedVariable(final List list) {
- condition.getModifiedVariable(list);
- if (action != null) {
- action.getModifiedVariable(list);
- }
- }
-
- /**
- * Get the variables used.
- */
- public void getUsedVariable(final List list) {
- condition.getUsedVariable(list);
- if (action != null) {
- action.getUsedVariable(list);
- }
- }
+ public Expression condition;
+
+ public Statement action;
+
+ private Label breakLabel, continueLabel;
+
+ int preCondInitStateIndex = -1;
+
+ int condIfTrueInitStateIndex = -1;
+
+ int mergedInitStateIndex = -1;
+
+ public WhileStatement(Expression condition, Statement action, int s, int e) {
+
+ this.condition = condition;
+ this.action = action;
+ sourceStart = s;
+ sourceEnd = e;
+ }
+
+ public FlowInfo analyseCode(BlockScope currentScope,
+ FlowContext flowContext, FlowInfo flowInfo) {
+
+ breakLabel = new Label();
+ continueLabel = new Label();
+
+ Constant cst = this.condition.constant;
+// boolean isConditionTrue = cst != NotAConstant
+// && cst.booleanValue() == true;
+ boolean isConditionFalse = cst != NotAConstant
+ && cst.booleanValue() == false;
+
+ cst = this.condition.optimizedBooleanConstant();
+ boolean isConditionOptimizedTrue = cst != NotAConstant
+ && cst.booleanValue() == true;
+ boolean isConditionOptimizedFalse = cst != NotAConstant
+ && cst.booleanValue() == false;
+
+ preCondInitStateIndex = currentScope.methodScope()
+ .recordInitializationStates(flowInfo);
+ LoopingFlowContext condLoopContext;
+ FlowInfo postCondInfo = this.condition.analyseCode(currentScope,
+ (condLoopContext = new LoopingFlowContext(flowContext, this,
+ null, null, currentScope)), flowInfo);
+
+ LoopingFlowContext loopingContext;
+ FlowInfo actionInfo;
+ // if (action == null
+ // || (action.isEmptyBlock() &&
+ // currentScope.environment().options.complianceLevel <=
+ // CompilerOptions.JDK1_3)) {
+ // condLoopContext.complainOnFinalAssignmentsInLoop(currentScope,
+ // postCondInfo);
+ // if (isConditionTrue) {
+ // return FlowInfo.DEAD_END;
+ // } else {
+ // FlowInfo mergedInfo =
+ // postCondInfo.initsWhenFalse().unconditionalInits();
+ // if (isConditionOptimizedTrue){
+ // mergedInfo.setReachMode(FlowInfo.UNREACHABLE);
+ // }
+ // mergedInitStateIndex =
+ // currentScope.methodScope().recordInitializationStates(mergedInfo);
+ // return mergedInfo;
+ // }
+ // } else {
+ // in case the condition was inlined to false, record the fact that
+ // there is no way to reach any
+ // statement inside the looping action
+ loopingContext = new LoopingFlowContext(flowContext, this, breakLabel,
+ continueLabel, currentScope);
+ if (isConditionFalse) {
+ actionInfo = FlowInfo.DEAD_END;
+ } else {
+ actionInfo = postCondInfo.initsWhenTrue().copy();
+ if (isConditionOptimizedFalse) {
+ actionInfo.setReachMode(FlowInfo.UNREACHABLE);
+ }
+ }
+
+ // for computing local var attributes
+ condIfTrueInitStateIndex = currentScope.methodScope()
+ .recordInitializationStates(postCondInfo.initsWhenTrue());
+
+ if (!actionInfo.complainIfUnreachable(action, currentScope, false)) {
+ actionInfo = action.analyseCode(currentScope, loopingContext,
+ actionInfo);
+ }
+
+ // code generation can be optimized when no need to continue in the loop
+ if (!actionInfo.isReachable()
+ && !loopingContext.initsOnContinue.isReachable()) {
+ continueLabel = null;
+ } else {
+ // TODO: (philippe) should simplify in one Loop context
+ condLoopContext.complainOnFinalAssignmentsInLoop(currentScope,
+ postCondInfo);
+ loopingContext.complainOnFinalAssignmentsInLoop(currentScope,
+ actionInfo);
+ }
+ // }
+
+ // infinite loop
+ FlowInfo mergedInfo;
+ if (isConditionOptimizedTrue) {
+ mergedInitStateIndex = currentScope.methodScope()
+ .recordInitializationStates(
+ mergedInfo = loopingContext.initsOnBreak);
+ return mergedInfo;
+ }
+
+ // end of loop: either condition false or break
+ mergedInfo = postCondInfo.initsWhenFalse().unconditionalInits()
+ .mergedWith(loopingContext.initsOnBreak);
+ if (isConditionOptimizedTrue && continueLabel == null) {
+ mergedInfo.setReachMode(FlowInfo.UNREACHABLE);
+ }
+ mergedInitStateIndex = currentScope.methodScope()
+ .recordInitializationStates(mergedInfo);
+ return mergedInfo;
+ }
+
+ /**
+ * While 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 ((bits & IsReachableMASK) == 0) {
+ // return;
+ // }
+ // int pc = codeStream.position;
+ // breakLabel.codeStream = codeStream;
+ //
+ // // generate condition
+ // if (continueLabel == null) {
+ // // no need to reverse condition
+ // if (condition.constant == NotAConstant) {
+ // condition.generateOptimizedBoolean(
+ // currentScope,
+ // codeStream,
+ // null,
+ // breakLabel,
+ // true);
+ // }
+ // } else {
+ // continueLabel.codeStream = codeStream;
+ // if (!(((condition.constant != NotAConstant)
+ // && (condition.constant.booleanValue() == true))
+ // || (action == null)
+ // || action.isEmptyBlock())) {
+ // int jumpPC = codeStream.position;
+ // codeStream.goto_(continueLabel);
+ // codeStream.recordPositionsFrom(jumpPC, condition.sourceStart);
+ // }
+ // }
+ // // generate the action
+ // Label actionLabel;
+ // (actionLabel = new Label(codeStream)).place();
+ // if (action != null) {
+ // // Required to fix 1PR0XVS: LFRE:WINNT - Compiler: variable table for
+ // method appears incorrect
+ // if (condIfTrueInitStateIndex != -1) {
+ // // insert all locals initialized inside the condition into the action
+ // generated prior to the condition
+ // codeStream.addDefinitelyAssignedVariables(
+ // currentScope,
+ // condIfTrueInitStateIndex);
+ // }
+ // action.generateCode(currentScope, codeStream);
+ // // May loose some local variable initializations : affecting the local
+ // variable attributes
+ // if (preCondInitStateIndex != -1) {
+ // codeStream.removeNotDefinitelyAssignedVariables(
+ // currentScope,
+ // preCondInitStateIndex);
+ // }
+ //
+ // }
+ // // output condition and branch back to the beginning of the repeated
+ // action
+ // if (continueLabel != null) {
+ // continueLabel.place();
+ // condition.generateOptimizedBoolean(
+ // currentScope,
+ // codeStream,
+ // actionLabel,
+ // null,
+ // true);
+ // }
+ // breakLabel.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 resetStateForCodeGeneration() {
+ if (this.breakLabel != null) {
+ this.breakLabel.resetStateForCodeGeneration();
+ }
+ if (this.continueLabel != null) {
+ this.continueLabel.resetStateForCodeGeneration();
+ }
+ }
+
+ public StringBuffer printStatement(int tab, StringBuffer output) {
+
+ printIndent(tab, output).append("while ("); //$NON-NLS-1$
+ condition.printExpression(0, output).append(')');
+ if (action == null)
+ output.append(';');
+ else
+ action.printStatement(tab + 1, output);
+ return output;
+ }
+
+ public void resolve(BlockScope scope) {
+
+ TypeBinding type = condition
+ .resolveTypeExpecting(scope, BooleanBinding);
+ condition.implicitWidening(type, type);
+ if (action != null)
+ action.resolve(scope);
+ }
+
+ public String toString(int tab) {
+
+ String s = tabString(tab);
+ s = s + "while (" + condition.toStringExpression() + ")"; //$NON-NLS-1$ //$NON-NLS-2$
+ if (action == null)
+ s = s + " {} ;"; //$NON-NLS-1$
+ else if (action instanceof Block)
+ s = s + "\n" + action.toString(tab + 1); //$NON-NLS-1$
+ else
+ s = s + " {\n" + action.toString(tab + 1) + "}"; //$NON-NLS-2$ //$NON-NLS-1$
+ return s;
+ }
+
+ public void traverse(ASTVisitor visitor, BlockScope blockScope) {
+
+ if (visitor.visit(this, blockScope)) {
+ condition.traverse(visitor, blockScope);
+ if (action != null)
+ action.traverse(visitor, blockScope);
+ }
+ visitor.endVisit(this, blockScope);
+ }
}
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