first scanner /parser copied from the jdt java version
[phpeclipse.git] / net.sourceforge.phpeclipse / src / net / sourceforge / phpdt / internal / compiler / ast / OR_OR_Expression.java
diff --git a/net.sourceforge.phpeclipse/src/net/sourceforge/phpdt/internal/compiler/ast/OR_OR_Expression.java b/net.sourceforge.phpeclipse/src/net/sourceforge/phpdt/internal/compiler/ast/OR_OR_Expression.java
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+/*******************************************************************************
+ * 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.*;
+
+//dedicated treatment for the ||
+public class OR_OR_Expression extends BinaryExpression {
+
+       int rightInitStateIndex = -1;
+       int mergedInitStateIndex = -1;
+
+       public OR_OR_Expression(Expression left, Expression right, int operator) {
+               super(left, right, operator);
+       }
+
+       public FlowInfo analyseCode(
+               BlockScope currentScope,
+               FlowContext flowContext,
+               FlowInfo flowInfo) {
+
+               Constant opConstant = left.conditionalConstant();
+               if (opConstant != NotAConstant) {
+                       if (opConstant.booleanValue() == false) {
+                               // FALSE || anything
+                                // need to be careful of scenario:
+                               //              (x || y) || !z, if passing the left info to the right, it would be swapped by the !
+                               FlowInfo mergedInfo = left.analyseCode(currentScope, flowContext, flowInfo).unconditionalInits();
+                               mergedInfo = right.analyseCode(currentScope, flowContext, mergedInfo);
+                               mergedInitStateIndex =
+                                       currentScope.methodScope().recordInitializationStates(mergedInfo);
+                               return mergedInfo;
+                       }
+               }
+               FlowInfo leftInfo, rightInfo;
+               leftInfo = left.analyseCode(currentScope, flowContext, flowInfo);
+       
+                // need to be careful of scenario:
+               //              (x || y) || !z, if passing the left info to the right, it would be swapped by the !
+               rightInfo = leftInfo.initsWhenFalse().unconditionalInits().copy();
+               if (opConstant != NotAConstant && opConstant.booleanValue() == true) rightInfo.markAsFakeReachable(true);
+
+               rightInitStateIndex =
+                       currentScope.methodScope().recordInitializationStates(rightInfo);
+               rightInfo = right.analyseCode(currentScope, flowContext, rightInfo);
+               FlowInfo mergedInfo = FlowInfo.conditional(
+                                       // merging two true initInfos for such a negative case: if ((t && (b = t)) || f) r = b; // b may not have been initialized
+                                       leftInfo.initsWhenTrue().copy().unconditionalInits().mergedWith(
+                                               rightInfo.initsWhenTrue().copy().unconditionalInits()),
+                                       rightInfo.initsWhenFalse().copy());
+               mergedInitStateIndex =
+                       currentScope.methodScope().recordInitializationStates(mergedInfo);
+               return mergedInfo;
+       }
+
+       /**
+        * Code generation for a binary operation
+        *
+        * @param currentScope org.eclipse.jdt.internal.compiler.lookup.BlockScope
+        * @param codeStream org.eclipse.jdt.internal.compiler.codegen.CodeStream
+        * @param valueRequired boolean
+        */
+       public void generateCode(
+               BlockScope currentScope,
+               CodeStream codeStream,
+               boolean valueRequired) {
+               int pc = codeStream.position;
+               Label falseLabel, endLabel;
+               if (constant != Constant.NotAConstant) {
+                       if (valueRequired)
+                               codeStream.generateConstant(constant, implicitConversion);
+                       codeStream.recordPositionsFrom(pc, this.sourceStart);
+                       return;
+               }
+               bits |= OnlyValueRequiredMASK;
+               generateOptimizedBoolean(
+                       currentScope,
+                       codeStream,
+                       null,
+                       (falseLabel = new Label(codeStream)),
+                       valueRequired);
+               /*  improving code gen for such a case:         boolean b = i < 0 || true; 
+                * since the label has never been used, we have the inlined value on the stack. */
+               if (falseLabel.hasForwardReferences()) {
+                       if (valueRequired) {
+                               codeStream.iconst_1();
+                               if ((bits & ValueForReturnMASK) != 0) {
+                                       codeStream.ireturn();
+                                       falseLabel.place();
+                                       codeStream.iconst_0();
+                               } else {
+                                       codeStream.goto_(endLabel = new Label(codeStream));
+                                       codeStream.decrStackSize(1);
+                                       falseLabel.place();
+                                       codeStream.iconst_0();
+                                       endLabel.place();
+                               }
+                       } else {
+                               falseLabel.place();
+                       }
+               }
+               if (valueRequired) {
+                       codeStream.generateImplicitConversion(implicitConversion);
+               }
+               codeStream.recordPositionsFrom(pc, this.sourceStart);
+       }
+
+       /**
+        * Boolean operator code generation
+        *      Optimized operations are: ||
+        */
+       public void generateOptimizedBoolean(
+               BlockScope currentScope,
+               CodeStream codeStream,
+               Label trueLabel,
+               Label falseLabel,
+               boolean valueRequired) {
+               if ((constant != Constant.NotAConstant) && (constant.typeID() == T_boolean)) {
+                       super.generateOptimizedBoolean(currentScope, codeStream, trueLabel, falseLabel, valueRequired);
+                       return;
+               }
+               int pc = codeStream.position;
+               Constant condConst;
+               if ((condConst = left.conditionalConstant()) != NotAConstant) {
+                       if (condConst.booleanValue() == true) {
+                               // <something equivalent to true> || x
+                               left.generateOptimizedBoolean(
+                                       currentScope,
+                                       codeStream,
+                                       trueLabel,
+                                       falseLabel,
+                                       false);
+                               if (valueRequired) {
+                                       if ((bits & OnlyValueRequiredMASK) != 0) {
+                                               codeStream.iconst_1();
+                                       } else {
+                                               if (trueLabel != null) {
+                                                       codeStream.goto_(trueLabel);
+                                               }
+                                       }
+                               }
+                       } else {
+                               // <something equivalent to false> || x
+                               left.generateOptimizedBoolean(
+                                       currentScope,
+                                       codeStream,
+                                       trueLabel,
+                                       falseLabel,
+                                       false);
+                               if (rightInitStateIndex != -1) {
+                                       codeStream.addDefinitelyAssignedVariables(currentScope, rightInitStateIndex);
+                               }
+                               if ((bits & OnlyValueRequiredMASK) != 0) {
+                                       right.generateCode(currentScope, codeStream, valueRequired);
+                               } else {
+                                       right.generateOptimizedBoolean(
+                                               currentScope,
+                                               codeStream,
+                                               trueLabel,
+                                               falseLabel,
+                                               valueRequired);
+                               }
+                       }
+                       codeStream.recordPositionsFrom(pc, this.sourceStart);
+                       if (mergedInitStateIndex != -1) {
+                               codeStream.removeNotDefinitelyAssignedVariables(
+                                       currentScope,
+                                       mergedInitStateIndex);
+                       }
+                       return;
+               }
+               if ((condConst = right.conditionalConstant()) != NotAConstant) {
+                       if (condConst.booleanValue() == true) {
+                               // x || <something equivalent to true>
+                               left.generateOptimizedBoolean(
+                                       currentScope,
+                                       codeStream,
+                                       trueLabel,
+                                       falseLabel,
+                                       false);
+                               if (rightInitStateIndex != -1) {
+                                       codeStream.addDefinitelyAssignedVariables(currentScope, rightInitStateIndex);
+                               }
+                               right.generateOptimizedBoolean(
+                                       currentScope,
+                                       codeStream,
+                                       trueLabel,
+                                       falseLabel,
+                                       false);
+                               if (valueRequired) {
+                                       if ((bits & OnlyValueRequiredMASK) != 0) {
+                                               codeStream.iconst_1();
+                                       } else {
+                                               if (trueLabel != null) {
+                                                       codeStream.goto_(trueLabel);
+                                               }
+                                       }
+                               }
+                       } else {
+                               // x || <something equivalent to false>
+                               if ((bits & OnlyValueRequiredMASK) != 0) {
+                                       left.generateCode(currentScope, codeStream, valueRequired);
+                               } else {
+                                       left.generateOptimizedBoolean(
+                                               currentScope,
+                                               codeStream,
+                                               trueLabel,
+                                               falseLabel,
+                                               valueRequired);
+                               }
+                               if (rightInitStateIndex != -1) {
+                                       codeStream.addDefinitelyAssignedVariables(currentScope, rightInitStateIndex);
+                               }
+                               right.generateOptimizedBoolean(
+                                       currentScope,
+                                       codeStream,
+                                       trueLabel,
+                                       falseLabel,
+                                       false);
+                       }
+                       codeStream.recordPositionsFrom(pc, this.sourceStart);
+                       if (mergedInitStateIndex != -1) {
+                               codeStream.removeNotDefinitelyAssignedVariables(
+                                       currentScope,
+                                       mergedInitStateIndex);
+                       }
+                       return;
+               }
+               // default case
+               if (falseLabel == null) {
+                       if (trueLabel != null) {
+                               // implicit falling through the FALSE case
+                               left.generateOptimizedBoolean(currentScope, codeStream, trueLabel, null, true);
+                               right.generateOptimizedBoolean(
+                                       currentScope,
+                                       codeStream,
+                                       trueLabel,
+                                       null,
+                                       valueRequired);
+                       }
+               } else {
+                       // implicit falling through the TRUE case
+                       if (trueLabel == null) {
+                               Label internalTrueLabel = new Label(codeStream);
+                               left.generateOptimizedBoolean(
+                                       currentScope,
+                                       codeStream,
+                                       internalTrueLabel,
+                                       null,
+                                       true);
+                               if (rightInitStateIndex != -1) {
+                                       codeStream.addDefinitelyAssignedVariables(currentScope, rightInitStateIndex);
+                               }
+                               right.generateOptimizedBoolean(
+                                       currentScope,
+                                       codeStream,
+                                       null,
+                                       falseLabel,
+                                       valueRequired);
+                               internalTrueLabel.place();
+                       } else {
+                               // no implicit fall through TRUE/FALSE --> should never occur
+                       }
+               }
+               codeStream.recordPositionsFrom(pc, this.sourceStart);
+               if (mergedInitStateIndex != -1) {
+                       codeStream.removeNotDefinitelyAssignedVariables(
+                               currentScope,
+                               mergedInitStateIndex);
+               }
+       }
+
+       public boolean isCompactableOperation() {
+               return false;
+       }
+
+       public void traverse(IAbstractSyntaxTreeVisitor visitor, BlockScope scope) {
+               if (visitor.visit(this, scope)) {
+                       left.traverse(visitor, scope);
+                       right.traverse(visitor, scope);
+               }
+               visitor.endVisit(this, scope);
+       }
+}
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