transtypes.java

是一款用JAVA 编写的编译器 具有很强的编译功能

    public void visitConditional(JCConditional tree) {
        tree.cond = translate(tree.cond, syms.booleanType);
        tree.truepart = translate(tree.truepart, erasure(tree.type));
        tree.falsepart = translate(tree.falsepart, erasure(tree.type));
        tree.type = erasure(tree.type);
        result = tree;
    }

   public void visitIf(JCIf tree) {
        tree.cond = translate(tree.cond, syms.booleanType);
        tree.thenpart = translate(tree.thenpart);
        tree.elsepart = translate(tree.elsepart);
        result = tree;
    }

    public void visitExec(JCExpressionStatement tree) {
        tree.expr = translate(tree.expr, null);
        result = tree;
    }

    public void visitReturn(JCReturn tree) {
        tree.expr = translate(tree.expr, currentMethod.sym.erasure(types).getReturnType());
        result = tree;
    }

    public void visitThrow(JCThrow tree) {
        tree.expr = translate(tree.expr, erasure(tree.expr.type));
        result = tree;
    }

    public void visitAssert(JCAssert tree) {
        tree.cond = translate(tree.cond, syms.booleanType);
        if (tree.detail != null)
            tree.detail = translate(tree.detail, erasure(tree.detail.type));
        result = tree;
    }

    public void visitApply(JCMethodInvocation tree) {
        tree.meth = translate(tree.meth, null);
        Symbol meth = TreeInfo.symbol(tree.meth);
        Type mt = meth.erasure(types);
        List<Type> argtypes = mt.getParameterTypes();
        if (allowEnums &&
            meth.name==names.init &&
            meth.owner == syms.enumSym)
            argtypes = argtypes.tail.tail;
        if (tree.varargsElement != null)
            tree.varargsElement = types.erasure(tree.varargsElement);
        else
            assert tree.args.length() == argtypes.length();
        tree.args = translateArgs(tree.args, argtypes, tree.varargsElement);

        // Insert casts of method invocation results as needed.
        result = retype(tree, mt.getReturnType(), pt);
    }

    public void visitNewClass(JCNewClass tree) {
        if (tree.encl != null)
            tree.encl = translate(tree.encl, erasure(tree.encl.type));
        tree.clazz = translate(tree.clazz, null);
        if (tree.varargsElement != null)
            tree.varargsElement = types.erasure(tree.varargsElement);
        tree.args = translateArgs(
            tree.args, tree.constructor.erasure(types).getParameterTypes(), tree.varargsElement);
        tree.def = translate(tree.def, null);
        tree.type = erasure(tree.type);
        result = tree;
    }

    public void visitNewArray(JCNewArray tree) {
        tree.elemtype = translate(tree.elemtype, null);
        translate(tree.dims, syms.intType);
        tree.elems = translate(tree.elems,
                               (tree.type == null) ? null
                               : erasure(types.elemtype(tree.type)));
        tree.type = erasure(tree.type);

        result = tree;
    }

    public void visitParens(JCParens tree) {
        tree.expr = translate(tree.expr, pt);
        tree.type = erasure(tree.type);
        result = tree;
    }

    public void visitAssign(JCAssign tree) {
        tree.lhs = translate(tree.lhs, null);
        tree.rhs = translate(tree.rhs, erasure(tree.lhs.type));
        tree.type = erasure(tree.type);
        result = tree;
    }

    public void visitAssignop(JCAssignOp tree) {
        tree.lhs = translate(tree.lhs, null);
        tree.rhs = translate(tree.rhs, erasure(tree.rhs.type));
        tree.type = erasure(tree.type);
        result = tree;
    }

    public void visitUnary(JCUnary tree) {
        tree.arg = translate(tree.arg, tree.operator.type.getParameterTypes().head);
        result = tree;
    }

    public void visitBinary(JCBinary tree) {
        tree.lhs = translate(tree.lhs, tree.operator.type.getParameterTypes().head);
        tree.rhs = translate(tree.rhs, tree.operator.type.getParameterTypes().tail.head);
        result = tree;
    }

    public void visitTypeCast(JCTypeCast tree) {
        tree.clazz = translate(tree.clazz, null);
        tree.type = erasure(tree.type);
        tree.expr = translate(tree.expr, tree.type);
        result = tree;
    }

    public void visitTypeTest(JCInstanceOf tree) {
        tree.expr = translate(tree.expr, null);
        tree.clazz = translate(tree.clazz, null);
        result = tree;
    }

    public void visitIndexed(JCArrayAccess tree) {
        tree.indexed = translate(tree.indexed, erasure(tree.indexed.type));
        tree.index = translate(tree.index, syms.intType);

        // Insert casts of indexed expressions as needed.
        result = retype(tree, types.elemtype(tree.indexed.type), pt);
    }

    // There ought to be nothing to rewrite here;
    // we don't generate code.
    public void visitAnnotation(JCAnnotation tree) {
        result = tree;
    }

    public void visitIdent(JCIdent tree) {
        Type et = tree.sym.erasure(types);

        // Map type variables to their bounds.
        if (tree.sym.kind == TYP && tree.sym.type.tag == TYPEVAR) {
            result = make.at(tree.pos).Type(et);
        } else
        // Map constants expressions to themselves.
        if (tree.type.constValue() != null) {
            result = tree;
        }
        // Insert casts of variable uses as needed.
        else if (tree.sym.kind == VAR) {
            result = retype(tree, et, pt);
        }
        else {
            tree.type = erasure(tree.type);
            result = tree;
        }
    }

    public void visitSelect(JCFieldAccess tree) {
        Type t = tree.selected.type;
        if (t.isCompound() || (t.tag == TYPEVAR && t.getUpperBound().isCompound())) {
            if ((tree.sym.flags() & IPROXY) != 0) {
                tree.sym = ((MethodSymbol)tree.sym).
                    implemented((TypeSymbol)tree.sym.owner, types);
            }
            tree.selected = cast(
                translate(tree.selected, erasure(t)),
                erasure(tree.sym.owner.type));
        } else
            tree.selected = translate(tree.selected, erasure(t));
        
        // Map constants expressions to themselves.
        if (tree.type.constValue() != null) {
            result = tree;
        }
        // Insert casts of variable uses as needed.
        else if (tree.sym.kind == VAR) {
            result = retype(tree, tree.sym.erasure(types), pt);
        }
        else {
            tree.type = erasure(tree.type);
            result = tree;
        }
    }

    public void visitTypeArray(JCArrayTypeTree tree) {
        tree.elemtype = translate(tree.elemtype, null);
        tree.type = erasure(tree.type);
        result = tree;
    }

    /** Visitor method for parameterized types.
     */
    public void visitTypeApply(JCTypeApply tree) {
        // Delete all type parameters.
        result = translate(tree.clazz, null);
    }

/**************************************************************************
 * utility methods
 *************************************************************************/

    private Type erasure(Type t) {
        return types.erasure(t);
    }

/**************************************************************************
 * main method
 *************************************************************************/

    private Env<AttrContext> env;

    void translateClass(ClassSymbol c) {
        Type st = types.supertype(c.type);

        // process superclass before derived
        if (st.tag == CLASS)
            translateClass((ClassSymbol)st.tsym);

        Env<AttrContext> myEnv = enter.typeEnvs.remove(c);
        if (myEnv == null)
            return;
        Env<AttrContext> oldEnv = env;
        try {
            env = myEnv;
            // class has not been translated yet

            TreeMaker savedMake = make;
            Type savedPt = pt;
            make = make.forToplevel(env.toplevel);
            pt = null;
            try {
                JCClassDecl tree = (JCClassDecl) env.tree;
                tree.typarams = List.nil();
                super.visitClassDef(tree);
                make.at(tree.pos);
                if (addBridges) {
                    ListBuffer<JCTree> bridges = new ListBuffer<JCTree>();
                    if ((tree.sym.flags() & INTERFACE) == 0)
                        addBridges(tree.pos(), tree.sym, bridges);
                    tree.defs = bridges.toList().prependList(tree.defs);
                }
                tree.type = erasure(tree.type);
            } finally {
                make = savedMake;
                pt = savedPt;
            }
        } finally {
            env = oldEnv;
        }
    }

    /** Translate a toplevel class definition.
     *  @param cdef    The definition to be translated.
     */
    public JCTree translateTopLevelClass(JCTree cdef, TreeMaker make) {
        // note that this method does NOT support recursion.
        this.make = make;
        pt = null;
        return translate(cdef, null);
    }
}