6653795: C2 intrinsic for Unsafe.getAddress performs pointer sign extension on 32-bit systems

Native pointers less than 64 bits wide should be extended as an unsigned number.

Reviewed-by: kvn, kevinw

hotspot/src/share/vm/opto/graphKit.cpp

@@ -1125,6 +1125,17 @@ Node* GraphKit::ConvI2L(Node* offset) {
   }
   return _gvn.transform( new (C) ConvI2LNode(offset));
 }
+
+Node* GraphKit::ConvI2UL(Node* offset) {
+  juint offset_con = (juint) find_int_con(offset, Type::OffsetBot);
+  if (offset_con != (juint) Type::OffsetBot) {
+    return longcon((julong) offset_con);
+  }
+  Node* conv = _gvn.transform( new (C) ConvI2LNode(offset));
+  Node* mask = _gvn.transform( ConLNode::make(C, (julong) max_juint) );
+  return _gvn.transform( new (C) AndLNode(conv, mask) );
+}
+
 Node* GraphKit::ConvL2I(Node* offset) {
   // short-circuit a common case
   jlong offset_con = find_long_con(offset, (jlong)Type::OffsetBot);

hotspot/src/share/vm/opto/graphKit.hpp

@@ -338,6 +338,7 @@ class GraphKit : public Phase {
   // Convert between int and long, and size_t.
   // (See macros ConvI2X, etc., in type.hpp for ConvI2X, etc.)
   Node* ConvI2L(Node* offset);
+  Node* ConvI2UL(Node* offset);
   Node* ConvL2I(Node* offset);
   // Find out the klass of an object.
   Node* load_object_klass(Node* object);

hotspot/src/share/vm/opto/library_call.cpp

@@ -2600,7 +2600,7 @@ bool LibraryCallKit::inline_unsafe_access(bool is_native_ptr, bool is_store, Bas
     case T_ADDRESS:
       // Cast to an int type.
       p = _gvn.transform(new (C) CastP2XNode(NULL, p));
-      p = ConvX2L(p);
+      p = ConvX2UL(p);
       break;
     default:
       fatal(err_msg_res("unexpected type %d: %s", type, type2name(type)));

hotspot/src/share/vm/opto/type.hpp

@@ -1716,6 +1716,7 @@ inline bool Type::is_ptr_to_boxing_obj() const {
 #define ConvL2X(x)   (x)
 #define ConvX2I(x)   ConvL2I(x)
 #define ConvX2L(x)   (x)
+#define ConvX2UL(x)  (x)
 
 #else
 
@@ -1760,6 +1761,7 @@ inline bool Type::is_ptr_to_boxing_obj() const {
 #define ConvL2X(x)   ConvL2I(x)
 #define ConvX2I(x)   (x)
 #define ConvX2L(x)   ConvI2L(x)
+#define ConvX2UL(x)  ConvI2UL(x)
 
 #endif
 

hotspot/test/compiler/intrinsics/unsafe/UnsafeGetAddressTest.java

@@ -0,0 +1,68 @@
+/*
+ * Copyright (c) 2014, 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.
+ *
+ * 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.
+ */
+
+/*
+ * @test
+ * @bug 6653795
+ * @summary C2 intrinsic for Unsafe.getAddress performs pointer sign extension on 32-bit systems
+ * @run main UnsafeGetAddressTest
+ *
+ */
+
+import sun.misc.Unsafe;
+import java.lang.reflect.*;
+
+public class UnsafeGetAddressTest {
+    private static Unsafe unsafe;
+
+    public static void main(String[] args) throws Exception {
+        Class c = UnsafeGetAddressTest.class.getClassLoader().loadClass("sun.misc.Unsafe");
+        Field f = c.getDeclaredField("theUnsafe");
+        f.setAccessible(true);
+        unsafe = (Unsafe)f.get(c);
+
+        long address = unsafe.allocateMemory(unsafe.addressSize());
+        unsafe.putAddress(address, 0x0000000080000000L);
+        // from sun.misc.Unsafe.getAddress' documentation:
+        // "If the native pointer is less than 64 bits wide, it is
+        // extended as an unsigned number to a Java long."
+        result = unsafe.getAddress(address);
+        System.out.printf("1: was 0x%x, expected 0x%x\n", result,
+                0x0000000080000000L);
+        for (int i = 0; i < 1000000; i++) {
+            result = unsafe.getAddress(address);
+        }
+
+        // The code has got compiled, check the result now
+        System.out.printf("2: was 0x%x, expected 0x%x\n", result,
+                0x0000000080000000L);
+        if (result != 0x0000000080000000L) {
+            System.out.println("Test Failed");
+            System.exit(97);
+        } else {
+            System.out.println("Test Passed");
+        }
+    }
+    static volatile long result;
+}
+