+/*******************************************************************************
+ * 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 net.sourceforge.phpdt.internal.compiler.flow.FlowContext;
+import net.sourceforge.phpdt.internal.compiler.flow.FlowInfo;
+import net.sourceforge.phpdt.internal.compiler.impl.Constant;
+import net.sourceforge.phpdt.internal.compiler.lookup.BaseTypeBinding;
+import net.sourceforge.phpdt.internal.compiler.lookup.BlockScope;
+import net.sourceforge.phpdt.internal.compiler.lookup.TypeBinding;
-/**
- * An expression.
- * @author Matthieu Casanova
- */
-public abstract class Expression extends Statement {
-
- /**
- * Create an expression giving starting and ending offset
- * @param sourceStart starting offset
- * @param sourceEnd ending offset
- */
- protected 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 final String toString(final int tab) {
- return tabString(tab) + toStringExpression();
- }
-
- /**
- * Return the expression as String.
- * @return the expression
- */
- public abstract String toStringExpression();
+public 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 TypeBinding resolvedType;
+
+ public Constant constant;
+
+ public Expression() {
+ super();
+ }
+
+ public FlowInfo analyseCode(BlockScope currentScope,
+ FlowContext flowContext, FlowInfo flowInfo) {
+
+ return flowInfo;
+ }
+
+ public FlowInfo analyseCode(BlockScope currentScope,
+ FlowContext flowContext, FlowInfo flowInfo, boolean valueRequired) {
+
+ return analyseCode(currentScope, flowContext, flowInfo);
+ }
+
+ /**
+ * Constant usable for bytecode pattern optimizations, but cannot be inlined
+ * since it is not strictly equivalent to the definition of constant
+ * expressions. In particular, some side-effects may be required to occur
+ * (only the end value is known). Constant is known to be of boolean type
+ */
+ public Constant optimizedBooleanConstant() {
+
+ return this.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
+ * 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;
+ // }
+ // generateCode(currentScope, codeStream, false);
+ // }
+ /**
+ * Every expression is responsible for generating its implicit conversion
+ * when necessary.
+ *
+ * @param currentScope
+ * net.sourceforge.phpdt.internal.compiler.lookup.BlockScope
+ * @param codeStream
+ * net.sourceforge.phpdt.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(ProjectPrefUtil.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 StringBuffer print(int indent, StringBuffer output) {
+ printIndent(indent, output);
+ return printExpression(indent, output);
+ }
+
+ public StringBuffer printExpression(int indent, StringBuffer output) {
+ output.append(super.toString(0));
+ return output;
+ }
+
+ public StringBuffer printStatement(int indent, StringBuffer output) {
+ return print(indent, output).append(";"); //$NON-NLS-1$
+ }
+
+ 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 expectedType) {
+
+ TypeBinding expressionType = this.resolveType(scope);
+ if (expressionType == null)
+ return null;
+ if (expressionType == expectedType)
+ return expressionType;
+
+ if (!expressionType.isCompatibleWith(expectedType)) {
+ scope.problemReporter().typeMismatchError(expressionType,
+ expectedType, this);
+ return null;
+ }
+ return expressionType;
+ }
+
+ 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;
+ }
}
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