classreader.java

是一款用JAVA 编写的编译器 具有很强的编译功能

    void indexPool() {
        poolIdx = new int[nextChar()];
        poolObj = new Object[poolIdx.length];
        int i = 1;
        while (i < poolIdx.length) {
            poolIdx[i++] = bp;
            byte tag = buf[bp++];
            switch (tag) {
            case CONSTANT_Utf8: case CONSTANT_Unicode: {
                int len = nextChar();
                bp = bp + len;
                break;
            }
            case CONSTANT_Class:
            case CONSTANT_String:
                bp = bp + 2;
                break;
            case CONSTANT_Fieldref:
            case CONSTANT_Methodref:
            case CONSTANT_InterfaceMethodref:
            case CONSTANT_NameandType:
            case CONSTANT_Integer:
            case CONSTANT_Float:
                bp = bp + 4;
                break;
            case CONSTANT_Long:
            case CONSTANT_Double:
                bp = bp + 8;
                i++;
                break;
            default:
                throw badClassFile("bad.const.pool.tag.at",
                                   Byte.toString(tag),
                                   Integer.toString(bp -1));
            }
        }
    }

    /** Read constant pool entry at start address i, use pool as a cache.
     */
    Object readPool(int i) {
        Object result = poolObj[i];
        if (result != null) return result;

        int index = poolIdx[i];
        if (index == 0) return null;

        byte tag = buf[index];
        switch (tag) {
        case CONSTANT_Utf8:
            poolObj[i] = names.fromUtf(buf, index + 3, getChar(index + 1));
            break;
        case CONSTANT_Unicode:
            throw badClassFile("unicode.str.not.supported");
        case CONSTANT_Class:
            poolObj[i] = readClassOrType(getChar(index + 1));
            break;
        case CONSTANT_String:
            // FIXME: (footprint) do not use toString here
            poolObj[i] = readName(getChar(index + 1)).toString();
            break;
        case CONSTANT_Fieldref: {
            ClassSymbol owner = readClassSymbol(getChar(index + 1));
            NameAndType nt = (NameAndType)readPool(getChar(index + 3));
            poolObj[i] = new VarSymbol(0, nt.name, nt.type, owner);
            break;
        }
        case CONSTANT_Methodref:
        case CONSTANT_InterfaceMethodref: {
            ClassSymbol owner = readClassSymbol(getChar(index + 1));
            NameAndType nt = (NameAndType)readPool(getChar(index + 3));
            poolObj[i] = new MethodSymbol(0, nt.name, nt.type, owner);
            break;
        }
        case CONSTANT_NameandType:
            poolObj[i] = new NameAndType(
                readName(getChar(index + 1)),
                readType(getChar(index + 3)));
            break;
        case CONSTANT_Integer:
            poolObj[i] = getInt(index + 1);
            break;
        case CONSTANT_Float:
            poolObj[i] = new Float(getFloat(index + 1));
            break;
        case CONSTANT_Long:
            poolObj[i] = new Long(getLong(index + 1));
            break;
        case CONSTANT_Double:
            poolObj[i] = new Double(getDouble(index + 1));
            break;
        default:
            throw badClassFile("bad.const.pool.tag", Byte.toString(tag));
        }
        return poolObj[i];
    }

    /** Read signature and convert to type.
     */
    Type readType(int i) {
        int index = poolIdx[i];
        return sigToType(buf, index + 3, getChar(index + 1));
    }

    /** If name is an array type or class signature, return the
     *  corresponding type; otherwise return a ClassSymbol with given name.
     */
    Object readClassOrType(int i) {
        int index =  poolIdx[i];
        int len = getChar(index + 1);
        int start = index + 3;
        assert buf[start] == '[' || buf[start + len - 1] != ';';
        // by the above assertion, the following test can be
        // simplified to (buf[start] == '[')
        return (buf[start] == '[' || buf[start + len - 1] == ';')
            ? (Object)sigToType(buf, start, len)
            : (Object)enterClass(names.fromUtf(internalize(buf, start,
                                                           len)));
    }

    /** Read signature and convert to type parameters.
     */
    List<Type> readTypeParams(int i) {
        int index = poolIdx[i];
        return sigToTypeParams(buf, index + 3, getChar(index + 1));
    }

    /** Read class entry.
     */
    ClassSymbol readClassSymbol(int i) {
        return (ClassSymbol) (readPool(i));
    }

    /** Read name.
     */
    Name readName(int i) {
        return (Name) (readPool(i));
    }

/************************************************************************
 * Reading Types
 ***********************************************************************/

    /** The unread portion of the currently read type is
     *  signature[sigp..siglimit-1].
     */
    byte[] signature;
    int sigp;
    int siglimit;
    boolean sigEnterPhase = false;

    /** Convert signature to type, where signature is a name.
     */
    Type sigToType(Name sig) {
        return sig == null
            ? null
            : sigToType(sig.table.names, sig.index, sig.len);
    }

    /** Convert signature to type, where signature is a byte array segment.
     */
    Type sigToType(byte[] sig, int offset, int len) {
        signature = sig;
        sigp = offset;
        siglimit = offset + len;
        return sigToType();
    }

    /** Convert signature to type, where signature is implicit.
     */
    Type sigToType() {
        switch ((char) signature[sigp]) {
        case 'T':
            sigp++;
            int start = sigp;
            while (signature[sigp] != ';') sigp++;
            sigp++;
            return sigEnterPhase
                ? Type.noType
                : findTypeVar(names.fromUtf(signature, start, sigp - 1 - start));
        case '+': {
            sigp++;
            Type t = sigToType();
            return new WildcardType(t, BoundKind.EXTENDS,
                                    syms.boundClass);
        }
        case '*':
            sigp++;
            return new WildcardType(syms.objectType, BoundKind.UNBOUND,
                                    syms.boundClass);
        case '-': {
            sigp++;
            Type t = sigToType();
            return new WildcardType(t, BoundKind.SUPER,
                                    syms.boundClass);
        }
        case 'B':
            sigp++;
            return syms.byteType;
        case 'C':
            sigp++;
            return syms.charType;
        case 'D':
            sigp++;
            return syms.doubleType;
        case 'F':
            sigp++;
            return syms.floatType;
        case 'I':
            sigp++;
            return syms.intType;
        case 'J':
            sigp++;
            return syms.longType;
        case 'L':
            {
                // int oldsigp = sigp;
                Type t = classSigToType();
                if (sigp < siglimit && signature[sigp] == '.')
                    throw badClassFile("deprecated inner class signature syntax " +
                                       "(please recompile from source)");
                /*
                System.err.println(" decoded " +
                                   new String(signature, oldsigp, sigp-oldsigp) +
                                   " => " + t + " outer " + t.outer());
                */
                return t;
            }
        case 'S':
            sigp++;
            return syms.shortType;
        case 'V':
            sigp++;
            return syms.voidType;
        case 'Z':
            sigp++;
            return syms.booleanType;
        case '[':
            sigp++;
            return new ArrayType(sigToType(), syms.arrayClass);
        case '(':
            sigp++;
            List<Type> argtypes = sigToTypes(')');
            Type restype = sigToType();
            List<Type> thrown = List.nil();
            while (signature[sigp] == '^') {
                sigp++;
                thrown = thrown.prepend(sigToType());
            }
            return new MethodType(argtypes,
                                  restype,
                                  thrown.reverse(),
                                  syms.methodClass);
        case '<':
            typevars = typevars.dup(currentOwner);
            Type poly = new ForAll(sigToTypeParams(), sigToType());
            typevars = typevars.leave();
            return poly;
        default:
            throw badClassFile("bad.signature",
                               Convert.utf2string(signature, sigp, 10));
        }
    }

    byte[] signatureBuffer = new byte[0];
    int sbp = 0;
    /** Convert class signature to type, where signature is implicit.
     */
    Type classSigToType() {
        if (signature[sigp] != 'L')
            throw badClassFile("bad.class.signature",
                               Convert.utf2string(signature, sigp, 10));
        sigp++;
        Type outer = Type.noType;
        int startSbp = sbp;

        while (true) {
            final byte c = signature[sigp++];
            switch (c) {

            case ';': {         // end
                ClassSymbol t = enterClass(names.fromUtf(signatureBuffer,
                                                         startSbp,
                                                         sbp - startSbp));
                if (outer == Type.noType)
                    outer = t.erasure(types);
                else
                    outer = new ClassType(outer, List.<Type>nil(), t);
                sbp = startSbp;
                return outer;
            }

            case '<':           // generic arguments
                ClassSymbol t = enterClass(names.fromUtf(signatureBuffer,
                                                         startSbp,
                                                         sbp - startSbp));
                outer = new ClassType(outer, sigToTypes('>'), t) {
                        boolean completed = false;
                        public Type getEnclosingType() {
                            if (!completed) {
                                completed = true;
                                tsym.complete();
                                Type enclosingType = tsym.type.getEnclosingType();
                                if (enclosingType != Type.noType) {
                                    List<Type> typeArgs =
                                        super.getEnclosingType().allparams();
                                    List<Type> typeParams =
                                        enclosingType.allparams();
                                    if (typeParams.length() != typeArgs.length()) {
                                        // no "rare" types
                                        super.setEnclosingType(types.erasure(enclosingType));
                                    } else {
                                        super.setEnclosingType(types.subst(enclosingType,
                                                                           typeParams,
                                                                           typeArgs));
                                    }
                                } else {
                                    super.setEnclosingType(Type.noType);
                                }
                            }
                            return super.getEnclosingType();
                        }
                        public void setEnclosingType(Type outer) {
                            throw new UnsupportedOperationException();
                        }
                    };
                switch (signature[sigp++]) {
                case ';':
                    if (sigp < signature.length && signature[sigp] == '.') {
                        // support old-style GJC signatures
                        // The signature produced was
                        // Lfoo/Outer<Lfoo/X;>;.Lfoo/Outer$Inner<Lfoo/Y;>;
                        // rather than say
                        // Lfoo/Outer<Lfoo/X;>.Inner<Lfoo/Y;>;
                        // so we skip past ".Lfoo/Outer$"
                        sigp += (sbp - startSbp) + // "foo/Outer"
                            3;  // ".L" and "$"
                        signatureBuffer[sbp++] = (byte)'$';
                        break;
                    } else {
                        sbp = startSbp;
                        return outer;
                    }
                case '.':
                    signatureBuffer[sbp++] = (byte)'$';
                    break;
                default:
                    throw new AssertionError(signature[sigp-1]);
                }
                continue;

            case '.':
                signatureBuffer[sbp++] = (byte)'$';
                continue;
            case '/':
                signatureBuffer[sbp++] = (byte)'.';
                continue;
            default: