--- /dev/null
+/*******************************************************************************
+ * Copyright (c) 2000, 2004 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 org.eclipse.jdt.internal.compiler.ast;
+
+import org.eclipse.jdt.internal.compiler.ASTVisitor;
+import org.eclipse.jdt.internal.compiler.codegen.*;
+import org.eclipse.jdt.internal.compiler.flow.*;
+import org.eclipse.jdt.internal.compiler.lookup.*;
+
+public class ReturnStatement extends Statement {
+
+ public Expression expression;
+ public TypeBinding expressionType;
+ public boolean isSynchronized;
+ public SubRoutineStatement[] subroutines;
+ public boolean isAnySubRoutineEscaping = false;
+ public LocalVariableBinding saveValueVariable;
+
+ public ReturnStatement(Expression expr, int s, int e ) {
+ sourceStart = s;
+ sourceEnd = e;
+ expression = expr ;
+ }
+ public FlowInfo analyseCode(BlockScope currentScope, FlowContext flowContext, FlowInfo flowInfo) { // here requires to generate a sequence of finally blocks invocations depending corresponding
+ // to each of the traversed try statements, so that execution will terminate properly.
+
+ // lookup the label, this should answer the returnContext
+
+ if (expression != null) {
+ flowInfo = expression.analyseCode(currentScope, flowContext, flowInfo);
+ }
+ // compute the return sequence (running the finally blocks)
+ FlowContext traversedContext = flowContext;
+ int subIndex = 0, maxSub = 5;
+ boolean saveValueNeeded = false;
+ boolean hasValueToSave = expression != null && expression.constant == NotAConstant;
+ do {
+ SubRoutineStatement sub;
+ if ((sub = traversedContext.subRoutine()) != null) {
+ if (this.subroutines == null){
+ this.subroutines = new SubRoutineStatement[maxSub];
+ }
+ if (subIndex == maxSub) {
+ System.arraycopy(this.subroutines, 0, (this.subroutines = new SubRoutineStatement[maxSub *= 2]), 0, subIndex); // grow
+ }
+ this.subroutines[subIndex++] = sub;
+ if (sub.isSubRoutineEscaping()) {
+ saveValueNeeded = false;
+ isAnySubRoutineEscaping = true;
+ break;
+ }
+ }
+ traversedContext.recordReturnFrom(flowInfo.unconditionalInits());
+
+ ASTNode node;
+ if ((node = traversedContext.associatedNode) instanceof SynchronizedStatement) {
+ isSynchronized = true;
+
+ } else if (node instanceof TryStatement) {
+ TryStatement tryStatement = (TryStatement) node;
+ flowInfo.addInitializationsFrom(tryStatement.subRoutineInits); // collect inits
+ if (hasValueToSave) {
+ if (this.saveValueVariable == null){ // closest subroutine secret variable is used
+ prepareSaveValueLocation(tryStatement);
+ }
+ saveValueNeeded = true;
+ }
+
+ } else if (traversedContext instanceof InitializationFlowContext) {
+ currentScope.problemReporter().cannotReturnInInitializer(this);
+ return FlowInfo.DEAD_END;
+ }
+ } while ((traversedContext = traversedContext.parent) != null);
+
+ // resize subroutines
+ if ((subroutines != null) && (subIndex != maxSub)) {
+ System.arraycopy(subroutines, 0, (subroutines = new SubRoutineStatement[subIndex]), 0, subIndex);
+ }
+
+ // secret local variable for return value (note that this can only occur in a real method)
+ if (saveValueNeeded) {
+ if (this.saveValueVariable != null) {
+ this.saveValueVariable.useFlag = LocalVariableBinding.USED;
+ }
+ } else {
+ this.saveValueVariable = null;
+ if ((!isSynchronized) && (expressionType == BooleanBinding)) {
+ this.expression.bits |= ValueForReturnMASK;
+ }
+ }
+ return FlowInfo.DEAD_END;
+ }
+
+ /**
+ * Retrun statement code generation
+ *
+ * generate the finallyInvocationSequence.
+ *
+ * @param currentScope org.eclipse.jdt.internal.compiler.lookup.BlockScope
+ * @param codeStream org.eclipse.jdt.internal.compiler.codegen.CodeStream
+ */
+ public void generateCode(BlockScope currentScope, CodeStream codeStream) {
+ if ((bits & IsReachableMASK) == 0) {
+ return;
+ }
+ int pc = codeStream.position;
+ // generate the expression
+ if ((expression != null) && (expression.constant == NotAConstant)) {
+ expression.generateCode(currentScope, codeStream, needValue()); // no value needed if non-returning subroutine
+ generateStoreSaveValueIfNecessary(codeStream);
+ }
+
+ // generation of code responsible for invoking the finally blocks in sequence
+ if (subroutines != null) {
+ for (int i = 0, max = subroutines.length; i < max; i++) {
+ SubRoutineStatement sub = subroutines[i];
+ sub.generateSubRoutineInvocation(currentScope, codeStream);
+ if (sub.isSubRoutineEscaping()) {
+ codeStream.recordPositionsFrom(pc, this.sourceStart);
+ SubRoutineStatement.reenterExceptionHandlers(subroutines, i, codeStream);
+ return;
+ }
+ sub.exitAnyExceptionHandler();
+ }
+ }
+ if (saveValueVariable != null) codeStream.load(saveValueVariable);
+
+ if ((expression != null) && (expression.constant != NotAConstant)) {
+ codeStream.generateConstant(expression.constant, expression.implicitConversion);
+ generateStoreSaveValueIfNecessary(codeStream);
+ }
+ // output the suitable return bytecode or wrap the value inside a descriptor for doits
+ this.generateReturnBytecode(codeStream);
+ codeStream.recordPositionsFrom(pc, this.sourceStart);
+ SubRoutineStatement.reenterExceptionHandlers(subroutines, -1, codeStream);
+ }
+ /**
+ * Dump the suitable return bytecode for a return statement
+ *
+ */
+ public void generateReturnBytecode(CodeStream codeStream) {
+
+ if (expression == null) {
+ codeStream.return_();
+ } else {
+ switch (expression.implicitConversion >> 4) {
+ case T_boolean :
+ case T_int :
+ codeStream.ireturn();
+ break;
+ case T_float :
+ codeStream.freturn();
+ break;
+ case T_long :
+ codeStream.lreturn();
+ break;
+ case T_double :
+ codeStream.dreturn();
+ break;
+ default :
+ codeStream.areturn();
+ }
+ }
+ }
+ public void generateStoreSaveValueIfNecessary(CodeStream codeStream){
+ if (saveValueVariable != null) codeStream.store(saveValueVariable, false);
+ }
+ public boolean needValue(){
+ return (subroutines == null) || (saveValueVariable != null) || isSynchronized;
+ }
+ public void prepareSaveValueLocation(TryStatement targetTryStatement){
+
+ this.saveValueVariable = targetTryStatement.secretReturnValue;
+ }
+ public StringBuffer printStatement(int tab, StringBuffer output){
+
+ printIndent(tab, output).append("return "); //$NON-NLS-1$
+ if (expression != null )
+ expression.printExpression(0, output) ;
+ return output.append(';');
+ }
+ public void resolve(BlockScope scope) {
+ MethodScope methodScope = scope.methodScope();
+ MethodBinding methodBinding;
+ TypeBinding methodType =
+ (methodScope.referenceContext instanceof AbstractMethodDeclaration)
+ ? ((methodBinding = ((AbstractMethodDeclaration) methodScope.referenceContext).binding) == null
+ ? null
+ : methodBinding.returnType)
+ : VoidBinding;
+ if (methodType == VoidBinding) {
+ // the expression should be null
+ if (expression == null)
+ return;
+ if ((expressionType = expression.resolveType(scope)) != null)
+ scope.problemReporter().attemptToReturnNonVoidExpression(this, expressionType);
+ return;
+ }
+ if (expression == null) {
+ if (methodType != null) scope.problemReporter().shouldReturn(methodType, this);
+ return;
+ }
+ if ((expressionType = expression.resolveType(scope)) == null)
+ return;
+
+ if (methodType != null && expression.isConstantValueOfTypeAssignableToType(expressionType, methodType)) {
+ // dealing with constant
+ expression.implicitWidening(methodType, expressionType);
+ return;
+ }
+ if (expressionType == VoidBinding) {
+ scope.problemReporter().attemptToReturnVoidValue(this);
+ return;
+ }
+ if (methodType != null && expressionType.isCompatibleWith(methodType)) {
+ expression.implicitWidening(methodType, expressionType);
+ return;
+ }
+ if (methodType != null){
+ scope.problemReporter().typeMismatchErrorActualTypeExpectedType(expression, expressionType, methodType);
+ }
+ }
+ public void traverse(ASTVisitor visitor, BlockScope scope) {
+ if (visitor.visit(this, scope)) {
+ if (expression != null)
+ expression.traverse(visitor, scope);
+ }
+ visitor.endVisit(this, scope);
+ }
+}
projects / org.ibex.tool.git / blobdiff