-/*******************************************************************************
- * 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.impl.*;
-import net.sourceforge.phpdt.internal.compiler.codegen.*;
-import net.sourceforge.phpdt.internal.compiler.flow.*;
-import net.sourceforge.phpdt.internal.compiler.lookup.*;
-import net.sourceforge.phpdt.internal.compiler.problem.*;
-import net.sourceforge.phpdt.internal.compiler.util.Util;
+/**
+ * An expression.
+ * @author Matthieu Casanova
+ */
public abstract class Expression extends Statement {
-
- //some expression may not be used - from a java semantic point
- //of view only - as statements. Other may. In order to avoid the creation
- //of wrappers around expression in order to tune them as expression
- //Expression is a subclass of Statement. See the message isValidJavaStatement()
- public int implicitConversion;
-
- public Constant constant;
-
- public Expression() {
- super();
- }
-
- public FlowInfo analyseCode(
- BlockScope currentScope,
- FlowContext flowContext,
- FlowInfo flowInfo,
- boolean valueRequired) {
-
- return analyseCode(currentScope, flowContext, flowInfo);
- }
-
- public Constant conditionalConstant() {
-
- return constant;
- }
-
- public static final boolean isConstantValueRepresentable(
- Constant constant,
- int constantTypeID,
- int targetTypeID) {
-
- //true if there is no loss of precision while casting.
- // constantTypeID == constant.typeID
- if (targetTypeID == constantTypeID)
- return true;
- switch (targetTypeID) {
- case T_char :
- switch (constantTypeID) {
- case T_char :
- return true;
- case T_double :
- return constant.doubleValue() == constant.charValue();
- case T_float :
- return constant.floatValue() == constant.charValue();
- case T_int :
- return constant.intValue() == constant.charValue();
- case T_short :
- return constant.shortValue() == constant.charValue();
- case T_byte :
- return constant.byteValue() == constant.charValue();
- case T_long :
- return constant.longValue() == constant.charValue();
- default :
- return false;//boolean
- }
-
- case T_float :
- switch (constantTypeID) {
- case T_char :
- return constant.charValue() == constant.floatValue();
- case T_double :
- return constant.doubleValue() == constant.floatValue();
- case T_float :
- return true;
- case T_int :
- return constant.intValue() == constant.floatValue();
- case T_short :
- return constant.shortValue() == constant.floatValue();
- case T_byte :
- return constant.byteValue() == constant.floatValue();
- case T_long :
- return constant.longValue() == constant.floatValue();
- default :
- return false;//boolean
- }
-
- case T_double :
- switch (constantTypeID) {
- case T_char :
- return constant.charValue() == constant.doubleValue();
- case T_double :
- return true;
- case T_float :
- return constant.floatValue() == constant.doubleValue();
- case T_int :
- return constant.intValue() == constant.doubleValue();
- case T_short :
- return constant.shortValue() == constant.doubleValue();
- case T_byte :
- return constant.byteValue() == constant.doubleValue();
- case T_long :
- return constant.longValue() == constant.doubleValue();
- default :
- return false; //boolean
- }
-
- case T_byte :
- switch (constantTypeID) {
- case T_char :
- return constant.charValue() == constant.byteValue();
- case T_double :
- return constant.doubleValue() == constant.byteValue();
- case T_float :
- return constant.floatValue() == constant.byteValue();
- case T_int :
- return constant.intValue() == constant.byteValue();
- case T_short :
- return constant.shortValue() == constant.byteValue();
- case T_byte :
- return true;
- case T_long :
- return constant.longValue() == constant.byteValue();
- default :
- return false; //boolean
- }
-
- case T_short :
- switch (constantTypeID) {
- case T_char :
- return constant.charValue() == constant.shortValue();
- case T_double :
- return constant.doubleValue() == constant.shortValue();
- case T_float :
- return constant.floatValue() == constant.shortValue();
- case T_int :
- return constant.intValue() == constant.shortValue();
- case T_short :
- return true;
- case T_byte :
- return constant.byteValue() == constant.shortValue();
- case T_long :
- return constant.longValue() == constant.shortValue();
- default :
- return false; //boolean
- }
-
- case T_int :
- switch (constantTypeID) {
- case T_char :
- return constant.charValue() == constant.intValue();
- case T_double :
- return constant.doubleValue() == constant.intValue();
- case T_float :
- return constant.floatValue() == constant.intValue();
- case T_int :
- return true;
- case T_short :
- return constant.shortValue() == constant.intValue();
- case T_byte :
- return constant.byteValue() == constant.intValue();
- case T_long :
- return constant.longValue() == constant.intValue();
- default :
- return false; //boolean
- }
-
- case T_long :
- switch (constantTypeID) {
- case T_char :
- return constant.charValue() == constant.longValue();
- case T_double :
- return constant.doubleValue() == constant.longValue();
- case T_float :
- return constant.floatValue() == constant.longValue();
- case T_int :
- return constant.intValue() == constant.longValue();
- case T_short :
- return constant.shortValue() == constant.longValue();
- case T_byte :
- return constant.byteValue() == constant.longValue();
- case T_long :
- return true;
- default :
- return false; //boolean
- }
-
- default :
- return false; //boolean
- }
- }
-
- /**
- * Expression statements are plain expressions, however they generate like
- * normal expressions with no value required.
- *
- * @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;
- }
- generateCode(currentScope, codeStream, false);
- }
-
- /**
- * Every expression is responsible for generating its implicit conversion when necessary.
- *
- * @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) {
-
- if (constant != NotAConstant) {
- // generate a constant expression
- int pc = codeStream.position;
- codeStream.generateConstant(constant, implicitConversion);
- codeStream.recordPositionsFrom(pc, this.sourceStart);
- } else {
- // actual non-constant code generation
- throw new ShouldNotImplement(Util.bind("ast.missingCode")); //$NON-NLS-1$
- }
- }
-
- /**
- * Default generation of a boolean value
- */
- public void generateOptimizedBoolean(
- BlockScope currentScope,
- CodeStream codeStream,
- Label trueLabel,
- Label falseLabel,
- boolean valueRequired) {
-
- // a label valued to nil means: by default we fall through the case...
- // both nil means we leave the value on the stack
-
- if ((constant != Constant.NotAConstant) && (constant.typeID() == T_boolean)) {
- int pc = codeStream.position;
- if (constant.booleanValue() == true) {
- // constant == true
- if (valueRequired) {
- if (falseLabel == null) {
- // implicit falling through the FALSE case
- if (trueLabel != null) {
- codeStream.goto_(trueLabel);
- }
- }
- }
- } else {
- if (valueRequired) {
- if (falseLabel != null) {
- // implicit falling through the TRUE case
- if (trueLabel == null) {
- codeStream.goto_(falseLabel);
- }
- }
- }
- }
- codeStream.recordPositionsFrom(pc, this.sourceStart);
- return;
- }
- generateCode(currentScope, codeStream, valueRequired);
- // branching
- int position = codeStream.position;
- if (valueRequired) {
- if (falseLabel == null) {
- if (trueLabel != null) {
- // Implicit falling through the FALSE case
- codeStream.ifne(trueLabel);
- }
- } else {
- if (trueLabel == null) {
- // Implicit falling through the TRUE case
- codeStream.ifeq(falseLabel);
- } else {
- // No implicit fall through TRUE/FALSE --> should never occur
- }
- }
- }
- // reposition the endPC
- codeStream.updateLastRecordedEndPC(position);
- }
-
- /* Optimized (java) code generation for string concatenations that involve StringBuffer
- * creation: going through this path means that there is no need for a new StringBuffer
- * creation, further operands should rather be only appended to the current one.
- * By default: no optimization.
- */
- public void generateOptimizedStringBuffer(
- BlockScope blockScope,
- net.sourceforge.phpdt.internal.compiler.codegen.CodeStream codeStream,
- int typeID) {
-
- generateCode(blockScope, codeStream, true);
- codeStream.invokeStringBufferAppendForType(typeID);
- }
-
- /* Optimized (java) code generation for string concatenations that involve StringBuffer
- * creation: going through this path means that there is no need for a new StringBuffer
- * creation, further operands should rather be only appended to the current one.
- */
- public void generateOptimizedStringBufferCreation(
- BlockScope blockScope,
- CodeStream codeStream,
- int typeID) {
-
- // Optimization only for integers and strings
- if (typeID == T_Object) {
- // in the case the runtime value of valueOf(Object) returns null, we have to use append(Object) instead of directly valueOf(Object)
- // append(Object) returns append(valueOf(Object)), which means that the null case is handled by append(String).
- codeStream.newStringBuffer();
- codeStream.dup();
- codeStream.invokeStringBufferDefaultConstructor();
- generateCode(blockScope, codeStream, true);
- codeStream.invokeStringBufferAppendForType(T_Object);
- return;
- }
- codeStream.newStringBuffer();
- codeStream.dup();
- if ((typeID == T_String) || (typeID == T_null)) {
- if (constant != NotAConstant) {
- codeStream.ldc(constant.stringValue());
- } else {
- generateCode(blockScope, codeStream, true);
- codeStream.invokeStringValueOf(T_Object);
- }
- } else {
- generateCode(blockScope, codeStream, true);
- codeStream.invokeStringValueOf(typeID);
- }
- codeStream.invokeStringBufferStringConstructor();
- }
-
- // Base types need that the widening is explicitly done by the compiler using some bytecode like i2f
- public void implicitWidening(
- TypeBinding runtimeTimeType,
- TypeBinding compileTimeType) {
-
- if (runtimeTimeType == null || compileTimeType == null)
- return;
-
- if (compileTimeType.id == T_null) {
- // this case is possible only for constant null
- // The type of runtime is a reference type
- // The code gen use the constant id thus any value
- // for the runtime id (akak the <<4) could be used.
- // T_Object is used as some general T_reference
- implicitConversion = (T_Object << 4) + T_null;
- return;
- }
-
- switch (runtimeTimeType.id) {
- case T_byte :
- case T_short :
- case T_char :
- implicitConversion = (T_int << 4) + compileTimeType.id;
- break;
- case T_String :
- case T_float :
- case T_boolean :
- case T_double :
- case T_int : //implicitConversion may result in i2i which will result in NO code gen
- case T_long :
- implicitConversion = (runtimeTimeType.id << 4) + compileTimeType.id;
- break;
- default : //nothing on regular object ref
- }
- }
-
- public boolean isCompactableOperation() {
-
- return false;
- }
-
- //Return true if the conversion is done AUTOMATICALLY by the vm
- //while the javaVM is an int based-machine, thus for example pushing
- //a byte onto the stack , will automatically creates a int on the stack
- //(this request some work d be done by the VM on signed numbers)
- public boolean isConstantValueOfTypeAssignableToType(
- TypeBinding constantType,
- TypeBinding targetType) {
-
- if (constant == Constant.NotAConstant)
- return false;
- if (constantType == targetType)
- return true;
- if (constantType.isBaseType() && targetType.isBaseType()) {
- //No free assignment conversion from anything but to integral ones.
- if ((constantType == IntBinding
- || BaseTypeBinding.isWidening(T_int, constantType.id))
- && (BaseTypeBinding.isNarrowing(targetType.id, T_int))) {
- //use current explicit conversion in order to get some new value to compare with current one
- return isConstantValueRepresentable(constant, constantType.id, targetType.id);
- }
- }
- return false;
- }
-
- public boolean isTypeReference() {
- return false;
- }
-
- public void resolve(BlockScope scope) {
- // drops the returning expression's type whatever the type is.
-
- this.resolveType(scope);
- return;
- }
-
- public TypeBinding resolveType(BlockScope scope) {
- // by default... subclasses should implement a better TC if required.
-
- return null;
- }
-
- public TypeBinding resolveTypeExpecting(
- BlockScope scope,
- TypeBinding expectedTb) {
-
- TypeBinding thisTb = this.resolveType(scope);
- if (thisTb == null)
- return null;
- if (!scope.areTypesCompatible(thisTb, expectedTb)) {
- scope.problemReporter().typeMismatchError(thisTb, expectedTb, this);
- return null;
- }
- return thisTb;
- }
-
- public String toString(int tab) {
-
- //Subclass re-define toStringExpression
- String s = tabString(tab);
- if (constant != null)
- //before TC has runned
- if (constant != NotAConstant)
- //after the TC has runned
- s += " /*cst:" + constant.toString() + "*/ "; //$NON-NLS-1$ //$NON-NLS-2$
- return s + toStringExpression(tab);
- }
-
- //Subclass re-define toStringExpression
- //This method is abstract and should never be called
- //but we provide some code that is running.....just in case
- //of developpement time (while every thing is not built)
- public String toStringExpression() {
-
- return super.toString(0);
- }
-
- public String toStringExpression(int tab) {
- // default is regular toString expression (qualified allocation expressions redifine this method)
- return this.toStringExpression();
- }
-
- public Expression toTypeReference() {
- //by default undefined
-
- //this method is meanly used by the parser in order to transform
- //an expression that is used as a type reference in a cast ....
- //--appreciate the fact that castExpression and ExpressionWithParenthesis
- //--starts with the same pattern.....
-
- return this;
- }
-}
\ No newline at end of file
+ /**
+ * Create an expression giving starting and ending offset
+ * @param sourceStart starting offset
+ * @param sourceEnd ending offset
+ */
+ public Expression(final int sourceStart, final int sourceEnd) {
+ super(sourceStart, sourceEnd);
+ }
+
+ /**
+ * Return the expression with a number of spaces before.
+ * @param tab how many spaces before the expression
+ * @return a string representing the expression
+ */
+ public String toString(final int tab) {
+ return tabString(tab) + toStringExpression();
+ }
+
+ /**
+ * Return the expression as String.
+ * @return the expression
+ */
+ public abstract String toStringExpression();
+}
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