tree.java

GJC编译器的源代码。是一个开放源代码的工业级编译器。

/**
 * @(#)Tree.java	1.30 03/01/23
 *
 * Copyright 2003 Sun Microsystems, Inc. All rights reserved.
 * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */
package com.sun.tools.javac.v8.tree;
import java.io.StringWriter;

import java.io.PrintWriter;

import com.sun.tools.javac.v8.util.*;

import com.sun.tools.javac.v8.code.*;

import com.sun.tools.javac.v8.code.Symbol.*;


/**
 * Root class for abstract syntax tree nodes. It provides
 *  definitions for specific tree nodes as subclasses nested inside
 *  There are 40 such subclasses.
 *
 *  Each subclass is highly standardized.  It generally contains only tree
 *  fields for the syntactic subcomponents of the node.  Some classes that
 *  represent identifier uses or definitions also define a
 *  Symbol field that denotes the represented identifier.  Classes
 *  for non-local jumps also carry the jump target as a field.  The root
 *  class Tree itself defines fields for the tree's type and
 *  position.  No other fields are kept in a tree node; instead parameters
 *  are passed to methods accessing the node.
 *
 *  The only method defined in subclasses is `visit' which applies a
 *  given visitor to the tree. The actual tree processing is done by
 *  visitor classes in other packages. The abstract class
 *  Visitor, as well as an Factory interface for trees, are
 *  defined as inner classes in Tree.
 *  @see TreeMaker
 *  @see TreeInfo
 *  @see TreeTranslator
 *  @see Pretty
 */
public abstract class Tree {

    /**
     * Toplevel nodes, of type TopLevel, representing entire source files.
     */
    public static final int TOPLEVEL = 1;

    /**
     * Import clauses, of type Import.
     */
    public static final int IMPORT = TOPLEVEL + 1;

    /**
     * Class definitions, of type ClassDef.
     */
    public static final int CLASSDEF = IMPORT + 1;

    /**
     * Method definitions, of type MethodDef.
     */
    public static final int METHODDEF = CLASSDEF + 1;

    /**
     * Variable definitions, of type VarDef.
     */
    public static final int VARDEF = METHODDEF + 1;

    /**
     * The no-op statement ";", of type Skip
     */
    public static final int SKIP = VARDEF + 1;

    /**
     * Blocks, of type Block.
     */
    public static final int BLOCK = SKIP + 1;

    /**
     * Do-while loops, of type DoLoop.
     */
    public static final int DOLOOP = BLOCK + 1;

    /**
     * While-loops, of type WhileLoop.
     */
    public static final int WHILELOOP = DOLOOP + 1;

    /**
     * For-loops, of type ForLoop.
     */
    public static final int FORLOOP = WHILELOOP + 1;

    /**
     * Labelled statements, of type Labelled.
     */
    public static final int LABELLED = FORLOOP + 1;

    /**
     * Switch statements, of type Switch.
     */
    public static final int SWITCH = LABELLED + 1;

    /**
     * Case parts in switch statements, of type Case.
     */
    public static final int CASE = SWITCH + 1;

    /**
     * Synchronized statements, of type Synchonized.
     */
    public static final int SYNCHRONIZED = CASE + 1;

    /**
     * Try statements, of type Try.
     */
    public static final int TRY = SYNCHRONIZED + 1;

    /**
     * Catch clauses in try statements, of type Catch.
     */
    public static final int CATCH = TRY + 1;

    /**
     * Conditional expressions, of type Conditional.
     */
    public static final int CONDEXPR = CATCH + 1;

    /**
     * Conditional statements, of type If.
     */
    public static final int IF = CONDEXPR + 1;

    /**
     * Expression statements, of type Exec.
     */
    public static final int EXEC = IF + 1;

    /**
     * Break statements, of type Break.
     */
    public static final int BREAK = EXEC + 1;

    /**
     * Continue statements, of type Continue.
     */
    public static final int CONTINUE = BREAK + 1;

    /**
     * Return statements, of type Return.
     */
    public static final int RETURN = CONTINUE + 1;

    /**
     * Throw statements, of type Throw.
     */
    public static final int THROW = RETURN + 1;

    /**
     * Assert statements, of type Assert.
     */
    public static final int ASSERT = THROW + 1;

    /**
     * Method invocation expressions, of type Apply.
     */
    public static final int APPLY = ASSERT + 1;

    /**
     * Class instance creation expressions, of type NewClass.
     */
    public static final int NEWCLASS = APPLY + 1;

    /**
     * Array creation expressions, of type NewArray.
     */
    public static final int NEWARRAY = NEWCLASS + 1;

    /**
     * Parenthesized subexpressions, of type Parens.
     */
    public static final int PARENS = NEWARRAY + 1;

    /**
     * Assignment expressions, of type Assign.
     */
    public static final int ASSIGN = PARENS + 1;

    /**
     * Type cast expressions, of type TypeCast.
     */
    public static final int TYPECAST = ASSIGN + 1;

    /**
     * Type test expressions, of type TypeTest.
     */
    public static final int TYPETEST = TYPECAST + 1;

    /**
     * Indexed array expressions, of type Indexed.
     */
    public static final int INDEXED = TYPETEST + 1;

    /**
     * Selections, of type Select.
     */
    public static final int SELECT = INDEXED + 1;

    /**
     * Simple identifiers, of type Ident.
     */
    public static final int IDENT = SELECT + 1;

    /**
     * Literals, of type Literal.
     */
    public static final int LITERAL = IDENT + 1;

    /**
     * Basic type identifiers, of type TypeIdent.
     */
    public static final int TYPEIDENT = LITERAL + 1;

    /**
     * Array types, of type TypeArray.
     */
    public static final int TYPEARRAY = TYPEIDENT + 1;

    /**
     * Parameterized types, of type TypeApply.
     */
    public static final int TYPEAPPLY = TYPEARRAY + 1;

    /**
     * Formal type parameters, of type TypeParameter.
     */
    public static final int TYPEPARAMETER = TYPEAPPLY + 1;

    /**
     * Error trees, of type Erroneous.
     */
    public static final int ERRONEOUS = TYPEPARAMETER + 1;

    /**
     * Unary operators, of type Unary.
     */
    public static final int POS = ERRONEOUS + 1;
    public static final int NEG = POS + 1;
    public static final int NOT = NEG + 1;
    public static final int COMPL = NOT + 1;
    public static final int PREINC = COMPL + 1;
    public static final int PREDEC = PREINC + 1;
    public static final int POSTINC = PREDEC + 1;
    public static final int POSTDEC = POSTINC + 1;

    /**
     * unary operator for null reference checks, only used internally.
     */
    public static final int NULLCHK = POSTDEC + 1;

    /**
     * Binary operators, of type Binary.
     */
    public static final int OR = NULLCHK + 1;
    public static final int AND = OR + 1;
    public static final int BITOR = AND + 1;
    public static final int BITXOR = BITOR + 1;
    public static final int BITAND = BITXOR + 1;
    public static final int EQ = BITAND + 1;
    public static final int NE = EQ + 1;
    public static final int LT = NE + 1;
    public static final int GT = LT + 1;
    public static final int LE = GT + 1;
    public static final int GE = LE + 1;
    public static final int SL = GE + 1;
    public static final int SR = SL + 1;
    public static final int USR = SR + 1;
    public static final int PLUS = USR + 1;
    public static final int MINUS = PLUS + 1;
    public static final int MUL = MINUS + 1;
    public static final int DIV = MUL + 1;
    public static final int MOD = DIV + 1;

    /**
     * Assignment operators, of type Assignop.
     */
    public static final int BITOR_ASG = MOD + 1;
    public static final int BITXOR_ASG = BITOR_ASG + 1;
    public static final int BITAND_ASG = BITXOR_ASG + 1;
    public static final int SL_ASG = SL + BITOR_ASG - BITOR;
    public static final int SR_ASG = SL_ASG + 1;
    public static final int USR_ASG = SR_ASG + 1;
    public static final int PLUS_ASG = USR_ASG + 1;
    public static final int MINUS_ASG = PLUS_ASG + 1;
    public static final int MUL_ASG = MINUS_ASG + 1;
    public static final int DIV_ASG = MUL_ASG + 1;
    public static final int MOD_ASG = DIV_ASG + 1;

    /**
     * The offset between assignment operators and normal operators.
     */
    public static final int ASGOffset = BITOR_ASG - BITOR;
    public int pos;
    public Type type;
    public int tag;

    /**
     * Initialize tree with given tag.
     */
    public Tree(int tag) {
        super();
        this.tag = tag;
    }

    /**
      * Convert a tree to a pretty-printed string.
      */
    public String toString() {
        StringWriter s = new StringWriter();
        new Pretty(new PrintWriter(s), false).printExpr(this);
        return s.toString();
    }

    /**
      * An empty list of trees.
      */
    public static final List emptyList = new List();

    /**
     * Set position field and return this tree.
     */
    public Tree setPos(int pos) {
        this.pos = pos;
        return this;
    }

    /**
      * Set type field and return this tree.
      */
    public Tree setType(Type type) {
        this.type = type;
        return this;
    }

    /**
      * Visit this tree with a given visitor.
      */
    public void accept(Visitor v) {
        v.visitTree(this);
    }

    /**
      * Everything in one source file is kept in a TopLevel structure.
      * @param pid              The tree representing the package clause.
      * @param sourcefile       The source file name.
      * @param defs             All definitions in this file.
      * @param packge           The package it belongs to.
      * @param namedImportScope A scope for all named imports.
      * @param starImportScope  A scope for all import-on-demands.
      * @param docComments      A hashtable that stores all documentation comments
      *                         indexed by the tree nodes they refer to.
      *                         defined only if option -s is set.
      * @param endPositions     A hashtable that stores ending positions of source
      *                         ranges indexed by the tree nodes they belong to.
      *                         Defined only if option -Xjcov is set.
      */
    public static class TopLevel extends Tree {
        public Tree pid;
        public List defs;
        public Name sourcefile;
        public PackageSymbol packge;
        public Scope namedImportScope;
        public Scope starImportScope;
        public Hashtable docComments = null;
        public Hashtable endPositions = null;

        public TopLevel(Tree pid, List defs, Name sourcefile,
                PackageSymbol packge, Scope namedImportScope, Scope starImportScope) {
            super(TOPLEVEL);
            this.pid = pid;
            this.defs = defs;
            this.sourcefile = sourcefile;
            this.packge = packge;
            this.namedImportScope = namedImportScope;
            this.starImportScope = starImportScope;
        }

        public void accept(Visitor v) {
            v.visitTopLevel(this);
        }
    }

    /**
      * An import clause.
      * @param qualid    The imported class(es).
      */
    public static class Import extends Tree {
        public Tree qualid;

        public Import(Tree qualid) {
            super(IMPORT);
            this.qualid = qualid;
        }

        public void accept(Visitor v) {
            v.visitImport(this);
        }
    }

    /**
      * A class definition.
      * @param flags class flags
      * @param name the name of the class
      * @param typarams formal class parameters
      * @param extending the classes this class extends
      * @param implementing the interfaces implemented by this class
      * @param defs all variables and methods defined in this class
      * @param sym the symbol
      */
    public static class ClassDef extends Tree {
        public long flags;
        public Name name;
        public List typarams;
        public Tree extending;
        public List implementing;
        public List defs;
        public ClassSymbol sym;

        public ClassDef(long flags, Name name, List typarams, Tree extending,
                List implementing, List defs, ClassSymbol sym) {
            super(CLASSDEF);
            this.flags = flags;
            this.name = name;
            this.typarams = typarams;
            this.extending = extending;
            this.implementing = implementing;
            this.defs = defs;
            this.sym = sym;
        }

        public void accept(Visitor v) {
            v.visitClassDef(this);
        }
    }

    /**
      * A method definition.
      * @param flags method flags
      * @param name method name
      * @param restype type of method return value
      * @param typarams type parameters
      * @param params value parameters
      * @param thrown exceptions thrown by this method
      * @param stats statements in the method
      * @param sym method symbol
      */
    public static class MethodDef extends Tree {
        public long flags;
        public Name name;
        public Tree restype;
        public List typarams;
        public List params;
        public List thrown;
        public Block body;
        public MethodSymbol sym;

        public MethodDef(long flags, Name name, Tree restype, List typarams,
                List params, List thrown, Block body, MethodSymbol sym) {
            super(METHODDEF);
            this.flags = flags;
            this.name = name;
            this.restype = restype;
            this.typarams = typarams;
            this.params = params;
            this.thrown = thrown;
            this.body = body;
            this.sym = sym;
        }

        public void accept(Visitor v) {
            v.visitMethodDef(this);
        }
    }

    /**
      * A variable definition.