--- a/jdk/src/share/classes/sun/dyn/util/VerifyType.java Wed Jul 05 17:38:31 2017 +0200
+++ /dev/null Thu Jan 01 00:00:00 1970 +0000
@@ -1,224 +0,0 @@
-/*
- * Copyright (c) 2008, 2010, Oracle and/or its affiliates. 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. Oracle designates this
- * particular file as subject to the "Classpath" exception as provided
- * by Oracle 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
- * or visit www.oracle.com if you need additional information or have any
- * questions.
- */
-
-package sun.dyn.util;
-
-import java.dyn.MethodType;
-import sun.dyn.empty.Empty;
-
-/**
- * This class centralizes information about the JVM verifier
- * and its requirements about type correctness.
- * @author jrose
- */
-public class VerifyType {
-
- private VerifyType() { } // cannot instantiate
-
- /**
- * True if a value can be stacked as the source type and unstacked as the
- * destination type, without violating the JVM's type consistency.
- *
- * @param call the type of a stacked value
- * @param recv the type by which we'd like to treat it
- * @return whether the retyping can be done without motion or reformatting
- */
- public static boolean isNullConversion(Class<?> src, Class<?> dst) {
- if (src == dst) return true;
- // Verifier allows any interface to be treated as Object:
- if (dst.isInterface()) dst = Object.class;
- if (src.isInterface()) src = Object.class;
- if (src == dst) return true; // check again
- if (dst == void.class) return true; // drop any return value
- if (isNullType(src)) return !dst.isPrimitive();
- if (!src.isPrimitive()) return dst.isAssignableFrom(src);
- // Verifier allows an int to carry byte, short, char, or even boolean:
- if (dst == int.class) return Wrapper.forPrimitiveType(src).isSubwordOrInt();
- return false;
- }
-
- /**
- * Specialization of isNullConversion to reference types.
-
- * @param call the type of a stacked value
- * @param recv the reference type by which we'd like to treat it
- * @return whether the retyping can be done without a cast
- */
- public static boolean isNullReferenceConversion(Class<?> src, Class<?> dst) {
- assert(!dst.isPrimitive());
- if (dst.isInterface()) return true; // verifier allows this
- if (isNullType(src)) return true;
- return dst.isAssignableFrom(src);
- }
-
- /**
- * Is the given type java.lang.Null or an equivalent null-only type?
- */
- public static boolean isNullType(Class<?> type) {
- if (type == null) return false;
- return type == NULL_CLASS
- // This one may also be used as a null type.
- // TO DO: Decide if we really want to legitimize it here.
- // Probably we do, unless java.lang.Null really makes it into Java 7
- //|| type == Void.class
- // Locally known null-only class:
- || type == Empty.class
- ;
- }
- private static final Class<?> NULL_CLASS;
- static {
- Class<?> nullClass = null;
- try {
- nullClass = Class.forName("java.lang.Null");
- } catch (ClassNotFoundException ex) {
- // OK, we'll cope
- }
- NULL_CLASS = nullClass;
- }
-
- /**
- * True if a method handle can receive a call under a slightly different
- * method type, without moving or reformatting any stack elements.
- *
- * @param call the type of call being made
- * @param recv the type of the method handle receiving the call
- * @return whether the retyping can be done without motion or reformatting
- */
- public static boolean isNullConversion(MethodType call, MethodType recv) {
- if (call == recv) return true;
- int len = call.parameterCount();
- if (len != recv.parameterCount()) return false;
- for (int i = 0; i < len; i++)
- if (!isNullConversion(call.parameterType(i), recv.parameterType(i)))
- return false;
- return isNullConversion(recv.returnType(), call.returnType());
- }
-
- //TO DO: isRawConversion
-
- /**
- * Determine if the JVM verifier allows a value of type call to be
- * passed to a formal parameter (or return variable) of type recv.
- * Returns 1 if the verifier allows the types to match without conversion.
- * Returns -1 if the types can be made to match by a JVM-supported adapter.
- * Cases supported are:
- * <ul><li>checkcast
- * </li><li>conversion between any two integral types (but not floats)
- * </li><li>unboxing from a wrapper to its corresponding primitive type
- * </li><li>conversion in either direction between float and double
- * </li></ul>
- * (Autoboxing is not supported here; it must be done via Java code.)
- * Returns 0 otherwise.
- */
- public static int canPassUnchecked(Class<?> src, Class<?> dst) {
- if (src == dst)
- return 1;
-
- if (dst.isPrimitive()) {
- if (dst == void.class)
- // Return anything to a caller expecting void.
- // This is a property of the implementation, which links
- // return values via a register rather than via a stack push.
- // This makes it possible to ignore cleanly.
- return 1;
- if (src == void.class)
- return 0; // void-to-something?
- if (!src.isPrimitive())
- // Cannot pass a reference to any primitive type (exc. void).
- return 0;
- Wrapper sw = Wrapper.forPrimitiveType(src);
- Wrapper dw = Wrapper.forPrimitiveType(dst);
- if (sw.isSubwordOrInt() && dw.isSubwordOrInt()) {
- if (sw.bitWidth() >= dw.bitWidth())
- return -1; // truncation may be required
- if (!dw.isSigned() && sw.isSigned())
- return -1; // sign elimination may be required
- }
- if (src == float.class || dst == float.class) {
- if (src == double.class || dst == double.class)
- return -1; // floating conversion may be required
- else
- return 0; // other primitive conversions NYI
- } else {
- // all fixed-point conversions are supported
- return 0;
- }
- } else if (src.isPrimitive()) {
- // Cannot pass a primitive to any reference type.
- // (Maybe allow null.class?)
- return 0;
- }
-
- // Handle reference types in the rest of the block:
-
- // The verifier treats interfaces exactly like Object.
- if (isNullReferenceConversion(src, dst))
- // pass any reference to object or an arb. interface
- return 1;
- // else it's a definite "maybe" (cast is required)
- return -1;
- }
-
- public static int canPassRaw(Class<?> src, Class<?> dst) {
- if (dst.isPrimitive()) {
- if (dst == void.class)
- // As above, return anything to a caller expecting void.
- return 1;
- if (src == void.class)
- // Special permission for raw conversions: allow a void
- // to be captured as a garbage int.
- // Caller promises that the actual value will be disregarded.
- return dst == int.class ? 1 : 0;
- if (isNullType(src))
- // Special permission for raw conversions: allow a null
- // to be reinterpreted as anything. For objects, it is safe,
- // and for primitives you get a garbage value (probably zero).
- return 1;
- if (!src.isPrimitive())
- return 0;
- Wrapper sw = Wrapper.forPrimitiveType(src);
- Wrapper dw = Wrapper.forPrimitiveType(dst);
- if (sw.stackSlots() == dw.stackSlots())
- return 1; // can do a reinterpret-cast on a stacked primitive
- if (sw.isSubwordOrInt() && dw == Wrapper.VOID)
- return 1; // can drop an outgoing int value
- return 0;
- } else if (src.isPrimitive()) {
- return 0;
- }
-
- // Both references.
- if (isNullReferenceConversion(src, dst))
- return 1;
- return -1;
- }
-
- public static boolean isSpreadArgType(Class<?> spreadArg) {
- return spreadArg.isArray();
- }
- public static Class<?> spreadArgElementType(Class<?> spreadArg, int i) {
- return spreadArg.getComponentType();
- }
-}