| /* |
| * reserved comment block |
| * DO NOT REMOVE OR ALTER! |
| */ |
| /* |
| * Copyright 2001-2004 The Apache Software Foundation. |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| /* |
| * $Id: Variable.java,v 1.2.4.1 2005/09/12 11:36:46 pvedula Exp $ |
| */ |
| |
| package com.sun.org.apache.xalan.internal.xsltc.compiler; |
| |
| import com.sun.org.apache.bcel.internal.classfile.Field; |
| import com.sun.org.apache.bcel.internal.generic.ACONST_NULL; |
| import com.sun.org.apache.bcel.internal.generic.ConstantPoolGen; |
| import com.sun.org.apache.bcel.internal.generic.DCONST; |
| import com.sun.org.apache.bcel.internal.generic.ICONST; |
| import com.sun.org.apache.bcel.internal.generic.InstructionHandle; |
| import com.sun.org.apache.bcel.internal.generic.InstructionList; |
| import com.sun.org.apache.bcel.internal.generic.PUTFIELD; |
| import com.sun.org.apache.xalan.internal.xsltc.compiler.util.BooleanType; |
| import com.sun.org.apache.xalan.internal.xsltc.compiler.util.ClassGenerator; |
| import com.sun.org.apache.xalan.internal.xsltc.compiler.util.ErrorMsg; |
| import com.sun.org.apache.xalan.internal.xsltc.compiler.util.IntType; |
| import com.sun.org.apache.xalan.internal.xsltc.compiler.util.MethodGenerator; |
| import com.sun.org.apache.xalan.internal.xsltc.compiler.util.NodeType; |
| import com.sun.org.apache.xalan.internal.xsltc.compiler.util.RealType; |
| import com.sun.org.apache.xalan.internal.xsltc.compiler.util.Type; |
| import com.sun.org.apache.xalan.internal.xsltc.compiler.util.TypeCheckError; |
| |
| final class Variable extends VariableBase { |
| |
| public int getIndex() { |
| return (_local != null) ? _local.getIndex() : -1; |
| } |
| |
| /** |
| * Parse the contents of the variable |
| */ |
| public void parseContents(Parser parser) { |
| // Parse 'name' and 'select' attributes plus parameter contents |
| super.parseContents(parser); |
| |
| // Add a ref to this var to its enclosing construct |
| SyntaxTreeNode parent = getParent(); |
| if (parent instanceof Stylesheet) { |
| // Mark this as a global variable |
| _isLocal = false; |
| // Check if a global variable with this name already exists... |
| Variable var = parser.getSymbolTable().lookupVariable(_name); |
| // ...and if it does we need to check import precedence |
| if (var != null) { |
| final int us = this.getImportPrecedence(); |
| final int them = var.getImportPrecedence(); |
| // It is an error if the two have the same import precedence |
| if (us == them) { |
| final String name = _name.toString(); |
| reportError(this, parser, ErrorMsg.VARIABLE_REDEF_ERR,name); |
| } |
| // Ignore this if previous definition has higher precedence |
| else if (them > us) { |
| _ignore = true; |
| copyReferences(var); |
| return; |
| } |
| else { |
| var.copyReferences(this); |
| var.disable(); |
| } |
| // Add this variable if we have higher precedence |
| } |
| ((Stylesheet)parent).addVariable(this); |
| parser.getSymbolTable().addVariable(this); |
| } |
| else { |
| _isLocal = true; |
| } |
| } |
| |
| /** |
| * Runs a type check on either the variable element body or the |
| * expression in the 'select' attribute |
| */ |
| public Type typeCheck(SymbolTable stable) throws TypeCheckError { |
| |
| // Type check the 'select' expression if present |
| if (_select != null) { |
| _type = _select.typeCheck(stable); |
| } |
| // Type check the element contents otherwise |
| else if (hasContents()) { |
| typeCheckContents(stable); |
| _type = Type.ResultTree; |
| } |
| else { |
| _type = Type.Reference; |
| } |
| // The return type is void as the variable element does not leave |
| // anything on the JVM's stack. The '_type' global will be returned |
| // by the references to this variable, and not by the variable itself. |
| return Type.Void; |
| } |
| |
| /** |
| * This method is part of a little trick that is needed to use local |
| * variables inside nested for-each loops. See the initializeVariables() |
| * method in the ForEach class for an explanation |
| */ |
| public void initialize(ClassGenerator classGen, MethodGenerator methodGen) { |
| final ConstantPoolGen cpg = classGen.getConstantPool(); |
| final InstructionList il = methodGen.getInstructionList(); |
| |
| // This is only done for local variables that are actually used |
| if (isLocal() && !_refs.isEmpty()) { |
| // Create a variable slot if none is allocated |
| if (_local == null) { |
| _local = methodGen.addLocalVariable2(getEscapedName(), |
| _type.toJCType(), |
| null); |
| } |
| // Push the default value on the JVM's stack |
| if ((_type instanceof IntType) || |
| (_type instanceof NodeType) || |
| (_type instanceof BooleanType)) |
| il.append(new ICONST(0)); // 0 for node-id, integer and boolean |
| else if (_type instanceof RealType) |
| il.append(new DCONST(0)); // 0.0 for floating point numbers |
| else |
| il.append(new ACONST_NULL()); // and 'null' for anything else |
| |
| // Mark the store as the start of the live range of the variable |
| _local.setStart(il.append(_type.STORE(_local.getIndex()))); |
| |
| } |
| } |
| |
| public void translate(ClassGenerator classGen, MethodGenerator methodGen) { |
| final ConstantPoolGen cpg = classGen.getConstantPool(); |
| final InstructionList il = methodGen.getInstructionList(); |
| |
| // Don't generate code for unreferenced variables |
| if (_refs.isEmpty()) { |
| _ignore = true; |
| } |
| |
| // Make sure that a variable instance is only compiled once |
| if (_ignore) return; |
| _ignore = true; |
| |
| final String name = getEscapedName(); |
| |
| if (isLocal()) { |
| // Compile variable value computation |
| translateValue(classGen, methodGen); |
| |
| // Add a new local variable and store value |
| boolean createLocal = _local == null; |
| if (createLocal) { |
| mapRegister(methodGen); |
| } |
| InstructionHandle storeInst = |
| il.append(_type.STORE(_local.getIndex())); |
| |
| // If the local is just being created, mark the store as the start |
| // of its live range. Note that it might have been created by |
| // initializeVariables already, which would have set the start of |
| // the live range already. |
| if (createLocal) { |
| _local.setStart(storeInst); |
| } |
| } |
| else { |
| String signature = _type.toSignature(); |
| |
| // Global variables are store in class fields |
| if (classGen.containsField(name) == null) { |
| classGen.addField(new Field(ACC_PUBLIC, |
| cpg.addUtf8(name), |
| cpg.addUtf8(signature), |
| null, cpg.getConstantPool())); |
| |
| // Push a reference to "this" for putfield |
| il.append(classGen.loadTranslet()); |
| // Compile variable value computation |
| translateValue(classGen, methodGen); |
| // Store the variable in the allocated field |
| il.append(new PUTFIELD(cpg.addFieldref(classGen.getClassName(), |
| name, signature))); |
| } |
| } |
| } |
| } |
