Refactored packagename to net.sourceforge.phpdt.internal.compiler.ast
[phpeclipse.git] / net.sourceforge.phpeclipse / src / net / sourceforge / phpdt / internal / compiler / ast / Expression.java
index d935982..69bd341 100644 (file)
+/*******************************************************************************
+ * 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
-   */
-  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();
+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;
+       }
 }