/*******************************************************************************
- * Copyright (c) 2000, 2001, 2002 International Business Machines Corp. and others.
+ * 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 v0.5
+ * 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-v05.html
+ * http://www.eclipse.org/legal/cpl-v10.html
*
* Contributors:
* IBM Corporation - initial API and implementation
- ******************************************************************************/
+ * Genady Beriozkin - added support for reporting assignment with no effect
+ *******************************************************************************/
package net.sourceforge.phpdt.internal.compiler.ast;
-import net.sourceforge.phpdt.internal.compiler.IAbstractSyntaxTreeVisitor;
-import net.sourceforge.phpdt.internal.compiler.codegen.CodeStream;
+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.lookup.BaseTypeBinding;
+import net.sourceforge.phpdt.internal.compiler.lookup.Binding;
import net.sourceforge.phpdt.internal.compiler.lookup.BlockScope;
import net.sourceforge.phpdt.internal.compiler.lookup.TypeBinding;
public class Assignment extends Expression {
- public Reference lhs;
+ public Expression lhs;
+
public Expression expression;
- public TypeBinding lhsType;
-
+
public Assignment(Expression lhs, Expression expression, int sourceEnd) {
- //lhs is always a reference by construction ,
- //but is build as an expression ==> the checkcast cannot fail
+ // lhs is always a reference by construction ,
+ // but is build as an expression ==> the checkcast cannot fail
+
+ this.lhs = lhs;
+ lhs.bits |= IsStrictlyAssignedMASK; // tag lhs as assigned
- this.lhs = (Reference) lhs;
this.expression = expression;
this.sourceStart = lhs.sourceStart;
this.sourceEnd = sourceEnd;
}
- public FlowInfo analyseCode(
- BlockScope currentScope,
- FlowContext flowContext,
- FlowInfo flowInfo) {
- // record setting a variable: various scenarii are possible, setting an array reference,
- // a field reference, a blank final field reference, a field of an enclosing instance or
+ public FlowInfo analyseCode(BlockScope currentScope,
+ FlowContext flowContext, FlowInfo flowInfo) {
+ // record setting a variable: various scenarii are possible, setting an
+ // array reference,
+ // a field reference, a blank final field reference, a field of an
+ // enclosing instance or
// just a local variable.
- return lhs
- .analyseAssignment(currentScope, flowContext, flowInfo, this, false)
- .unconditionalInits();
+ return ((Reference) lhs).analyseAssignment(currentScope, flowContext,
+ flowInfo, this, false).unconditionalInits();
}
- public void generateCode(
- BlockScope currentScope,
- CodeStream codeStream,
- boolean valueRequired) {
+ void checkAssignmentEffect(BlockScope scope) {
- // various scenarii are possible, setting an array reference,
- // a field reference, a blank final field reference, a field of an enclosing instance or
- // just a local variable.
+ Binding left = getDirectBinding(this.lhs);
+ if (left != null && left == getDirectBinding(this.expression)) {
+ scope.problemReporter().assignmentHasNoEffect(this,
+ left.shortReadableName());
+ this.bits |= IsAssignmentWithNoEffectMASK; // record assignment has
+ // no effect
+ }
+ }
+
+ // public void generateCode(
+ // BlockScope currentScope,
+ // CodeStream codeStream,
+ // boolean valueRequired) {
+ //
+ // // various scenarii are possible, setting an array reference,
+ // // a field reference, a blank final field reference, a field of an
+ // enclosing instance or
+ // // just a local variable.
+ //
+ // int pc = codeStream.position;
+ // if ((this.bits & IsAssignmentWithNoEffectMASK) != 0) {
+ // if (valueRequired) {
+ // this.expression.generateCode(currentScope, codeStream, true);
+ // }
+ // } else {
+ // ((Reference) lhs).generateAssignment(currentScope, codeStream, this,
+ // valueRequired);
+ // // variable may have been optimized out
+ // // the lhs is responsible to perform the implicitConversion generation
+ // for the assignment since optimized for unused local assignment.
+ // }
+ // codeStream.recordPositionsFrom(pc, this.sourceStart);
+ // }
+
+ Binding getDirectBinding(Expression someExpression) {
+ if (someExpression instanceof SingleNameReference) {
+ return ((SingleNameReference) someExpression).binding;
+ } else if (someExpression instanceof FieldReference) {
+ FieldReference fieldRef = (FieldReference) someExpression;
+ if (fieldRef.receiver.isThis()
+ && !(fieldRef.receiver instanceof QualifiedThisReference)) {
+ return fieldRef.binding;
+ }
+ }
+ return null;
+ }
+
+ public StringBuffer print(int indent, StringBuffer output) {
+
+ // no () when used as a statement
+ printIndent(indent, output);
+ return printExpressionNoParenthesis(indent, output);
+ }
+
+ public StringBuffer printExpression(int indent, StringBuffer output) {
- int pc = codeStream.position;
- lhs.generateAssignment(currentScope, codeStream, this, valueRequired);
- // variable may have been optimized out
- // the lhs is responsible to perform the implicitConversion generation for the assignment since optimized for unused local assignment.
- codeStream.recordPositionsFrom(pc, this.sourceStart);
+ // subclass redefine printExpressionNoParenthesis()
+ output.append('(');
+ return printExpressionNoParenthesis(0, output).append(')');
+ }
+
+ public StringBuffer printExpressionNoParenthesis(int indent,
+ StringBuffer output) {
+
+ lhs.printExpression(indent, output).append(" = "); //$NON-NLS-1$
+ return expression.printExpression(0, output);
+ }
+
+ public StringBuffer printStatement(int indent, StringBuffer output) {
+
+ // no () when used as a statement
+ return print(indent, output).append(';');
}
public TypeBinding resolveType(BlockScope scope) {
- // due to syntax lhs may be only a NameReference, a FieldReference or an ArrayReference
+ // due to syntax lhs may be only a NameReference, a FieldReference or an
+ // ArrayReference
constant = NotAConstant;
- this.lhsType = lhs.resolveType(scope);
- TypeBinding expressionTb = expression.resolveType(scope);
- if (this.lhsType == null || expressionTb == null)
+ if (!(this.lhs instanceof Reference)) {
+ scope.problemReporter().expressionShouldBeAVariable(this.lhs);
+ }
+ this.resolvedType = lhs.resolveType(scope); // expressionType contains
+ // the assignment type (lhs
+ // Type)
+ TypeBinding rhsType = expression.resolveType(scope);
+ if (this.resolvedType == null || rhsType == null) {
return null;
+ }
+ checkAssignmentEffect(scope);
- // Compile-time conversion of base-types : implicit narrowing integer into byte/short/character
+ // Compile-time conversion of base-types : implicit narrowing integer
+ // into byte/short/character
// may require to widen the rhs expression at runtime
- if ((expression.isConstantValueOfTypeAssignableToType(expressionTb, this.lhsType)
- || (this.lhsType.isBaseType() && BaseTypeBinding.isWidening(this.lhsType.id, expressionTb.id)))
- || (BlockScope.areTypesCompatible(expressionTb, this.lhsType))) {
- expression.implicitWidening(this.lhsType, expressionTb);
- return this.lhsType;
+ if ((expression.isConstantValueOfTypeAssignableToType(rhsType,
+ this.resolvedType) || (this.resolvedType.isBaseType() && BaseTypeBinding
+ .isWidening(this.resolvedType.id, rhsType.id)))
+ || rhsType.isCompatibleWith(this.resolvedType)) {
+ expression.implicitWidening(this.resolvedType, rhsType);
+ return this.resolvedType;
}
scope.problemReporter().typeMismatchErrorActualTypeExpectedType(
- expression,
- expressionTb,
- this.lhsType);
- return null;
+ expression, rhsType, this.resolvedType);
+ return this.resolvedType;
}
public String toString(int tab) {
- //no () when used as a statement
+ // no () when used as a statement
return tabString(tab) + toStringExpressionNoParenthesis();
}
public String toStringExpression() {
- //subclass redefine toStringExpressionNoParenthesis()
+ // subclass redefine toStringExpressionNoParenthesis()
return "(" + toStringExpressionNoParenthesis() + ")"; //$NON-NLS-2$ //$NON-NLS-1$
- }
-
+ }
+
public String toStringExpressionNoParenthesis() {
- return lhs.toStringExpression() + " " //$NON-NLS-1$
- + "=" //$NON-NLS-1$
- + ((expression.constant != null) && (expression.constant != NotAConstant)
- ? " /*cst:" + expression.constant.toString() + "*/ " //$NON-NLS-1$ //$NON-NLS-2$
- : " ") //$NON-NLS-1$
- + expression.toStringExpression();
+ return lhs.toStringExpression()
+ + " " //$NON-NLS-1$
+ + "=" //$NON-NLS-1$
+ + ((expression.constant != null)
+ && (expression.constant != NotAConstant) ? " /*cst:" + expression.constant.toString() + "*/ " //$NON-NLS-1$ //$NON-NLS-2$
+ : " ") //$NON-NLS-1$
+ + expression.toStringExpression();
}
- public void traverse(IAbstractSyntaxTreeVisitor visitor, BlockScope scope) {
-
+
+ public void traverse(ASTVisitor visitor, BlockScope scope) {
+
if (visitor.visit(this, scope)) {
lhs.traverse(visitor, scope);
expression.traverse(visitor, scope);
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