symtab.java

来自「是一款用JAVA 编写的编译器 具有很强的编译功能」· Java 代码 · 共 578 行 · 第 1/2 页

/*
 * Copyright 1999-2006 Sun Microsystems, Inc.  All Rights Reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Sun designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Sun in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
 * CA 95054 USA or visit www.sun.com if you need additional information or
 * have any questions.
 */

package com.sun.tools.javac.code;

import java.util.*;

import com.sun.tools.javac.util.*;
import com.sun.tools.javac.util.List;
import com.sun.tools.javac.code.Symbol.*;
import com.sun.tools.javac.code.Type.*;
import com.sun.tools.javac.jvm.*;

import static com.sun.tools.javac.jvm.ByteCodes.*;
import static com.sun.tools.javac.code.Flags.*;

/** A class that defines all predefined constants and operators
 *  as well as special classes such as java.lang.Object, which need
 *  to be known to the compiler. All symbols are held in instance
 *  fields. This makes it possible to work in multiple concurrent
 *  projects, which might use different class files for library classes.
 *
 *  <p><b>This is NOT part of any API supported by Sun Microsystems.  If
 *  you write code that depends on this, you do so at your own risk.
 *  This code and its internal interfaces are subject to change or
 *  deletion without notice.</b>
 */
public class Symtab {
    /** The context key for the symbol table. */
    protected static final Context.Key<Symtab> symtabKey =
	new Context.Key<Symtab>();

    /** Get the symbol table instance. */
    public static Symtab instance(Context context) {
	Symtab instance = context.get(symtabKey);
	if (instance == null)
	    instance = new Symtab(context);
	return instance;
    }

    /** Builtin types.
     */
    public final Type byteType = new Type(TypeTags.BYTE, null);       
    public final Type charType = new Type(TypeTags.CHAR, null);       
    public final Type shortType = new Type(TypeTags.SHORT, null);     
    public final Type intType = new Type(TypeTags.INT, null);         
    public final Type longType = new Type(TypeTags.LONG, null);       
    public final Type floatType = new Type(TypeTags.FLOAT, null);     
    public final Type doubleType = new Type(TypeTags.DOUBLE, null);   
    public final Type booleanType = new Type(TypeTags.BOOLEAN, null); 
    public final Type botType = new BottomType();
    public final JCNoType voidType = new JCNoType(TypeTags.VOID);

    private final Name.Table names;
    private final ClassReader reader;

    /** A symbol for the root package.
     */
    public final PackageSymbol rootPackage;

    /** A symbol for the unnamed package.
     */
    public final PackageSymbol unnamedPackage;

    /** A symbol that stands for a missing symbol.
     */
    public final TypeSymbol noSymbol;

    /** The error symbol.
     */
    public final ClassSymbol errSymbol;

    /** An instance of the error type.
     */
    public final Type errType;

    /** A value for the unknown type. */
    public final Type unknownType;

    /** The builtin type of all arrays. */
    public final ClassSymbol arrayClass;
    public final MethodSymbol arrayCloneMethod;

    /** VGJ: The (singleton) type of all bound types. */
    public final ClassSymbol boundClass;

    /** The builtin type of all methods. */
    public final ClassSymbol methodClass;

    /** Predefined types.
     */
    public final Type objectType;
    public final Type classType;
    public final Type classLoaderType;
    public final Type stringType;
    public final Type stringBufferType;
    public final Type stringBuilderType;
    public final Type cloneableType;
    public final Type serializableType;
    public final Type throwableType;
    public final Type errorType;
    public final Type illegalArgumentExceptionType;
    public final Type exceptionType;
    public final Type runtimeExceptionType;
    public final Type classNotFoundExceptionType;
    public final Type noClassDefFoundErrorType;
    public final Type noSuchFieldErrorType;
    public final Type assertionErrorType;
    public final Type cloneNotSupportedExceptionType;
    public final Type annotationType;
    public final TypeSymbol enumSym;
    public final Type listType;
    public final Type collectionsType;
    public final Type comparableType;
    public final Type arraysType;
    public final Type iterableType;
    public final Type iteratorType;
    public final Type annotationTargetType;
    public final Type overrideType;
    public final Type retentionType;
    public final Type deprecatedType;
    public final Type suppressWarningsType;
    public final Type inheritedType;
    public final Type proprietaryType;

    /** The symbol representing the length field of an array.
     */
    public final VarSymbol lengthVar;

    /** The null check operator. */
    public final OperatorSymbol nullcheck;

    /** The symbol representing the final finalize method on enums */
    public final MethodSymbol enumFinalFinalize;

    /** The predefined type that belongs to a tag.
     */
    public final Type[] typeOfTag = new Type[TypeTags.TypeTagCount];

    /** The name of the class that belongs to a basix type tag.
     */
    public final Name[] boxedName = new Name[TypeTags.TypeTagCount];

    /** A hashtable containing the encountered top-level and member classes,
     *  indexed by flat names. The table does not contain local classes.
     *  It should be updated from the outside to reflect classes defined
     *  by compiled source files.
     */
    public final Map<Name, ClassSymbol> classes = new HashMap<Name, ClassSymbol>();

    /** A hashtable containing the encountered packages.
     *  the table should be updated from outside to reflect packages defined
     *  by compiled source files.
     */
    public final Map<Name, PackageSymbol> packages = new HashMap<Name, PackageSymbol>();

    public void initType(Type type, ClassSymbol c) {
	type.tsym = c;
	typeOfTag[type.tag] = type;
    }

    public void initType(Type type, String name) {
	initType(
	    type,
	    new ClassSymbol(
		PUBLIC, names.fromString(name), type, rootPackage));
    }

    public void initType(Type type, String name, String bname) {
	initType(type, name);
	boxedName[type.tag] = names.fromString("java.lang." + bname);
    }

    /** The class symbol that owns all predefined symbols.
     */
    public final ClassSymbol predefClass;

    /** Enter a constant into symbol table.
     *  @param name   The constant's name.
     *  @param type   The constant's type.
     */
    private VarSymbol enterConstant(String name, Type type) {
        VarSymbol c = new VarSymbol(
	    PUBLIC | STATIC | FINAL,
	    names.fromString(name),
	    type,
	    predefClass);
	c.setData(type.constValue());
        predefClass.members().enter(c);
	return c;
    }

    /** Enter a binary operation into symbol table.
     *  @param name     The name of the operator.
     *  @param left     The type of the left operand.
     *  @param right    The type of the left operand.
     *  @param res      The operation's result type.
     *  @param opcode   The operation's bytecode instruction.
     */
    private void enterBinop(String name,
			    Type left, Type right, Type res,
			    int opcode) {
        predefClass.members().enter(
            new OperatorSymbol(
		names.fromString(name),
		new MethodType(List.of(left, right), res,
			       List.<Type>nil(), methodClass),
		opcode,
		predefClass));
    }

    /** Enter a binary operation, as above but with two opcodes,
     *  which get encoded as (opcode1 << ByteCodeTags.preShift) + opcode2.
     *  @param opcode1     First opcode.
     *  @param opcode2     Second opcode.
     */
    private void enterBinop(String name,
			    Type left, Type right, Type res,
			    int opcode1, int opcode2) {
	enterBinop(
	    name, left, right, res, (opcode1 << ByteCodes.preShift) | opcode2);
    }

    /** Enter a unary operation into symbol table.
     *  @param name     The name of the operator.
     *  @param arg      The type of the operand.
     *  @param res      The operation's result type.
     *  @param opcode   The operation's bytecode instruction.
     */
    private OperatorSymbol enterUnop(String name,
				     Type arg,
				     Type res,
				     int opcode) {
	OperatorSymbol sym =
	    new OperatorSymbol(names.fromString(name),
			       new MethodType(List.of(arg),
					      res,
					      List.<Type>nil(),
					      methodClass),
			       opcode,
			       predefClass);
        predefClass.members().enter(sym);
	return sym;
    }

    /** Enter a class into symbol table.
     *  @param    The name of the class.
     */
    private Type enterClass(String s) {
	return reader.enterClass(names.fromString(s)).type;
    }

    /** Constructor; enters all predefined identifiers and operators
     *  into symbol table.
     */
    protected Symtab(Context context) throws CompletionFailure {
	context.put(symtabKey, this);

	names = Name.Table.instance(context);

	// Create the unknown type
	unknownType = new Type(TypeTags.UNKNOWN, null);

	// create the basic builtin symbols
	rootPackage = new PackageSymbol(names.empty, null);
        final Messages messages = Messages.instance(context);
        unnamedPackage = new PackageSymbol(names.empty, rootPackage) {