--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/hotspot/src/cpu/x86/vm/metaspaceShared_x86_64.cpp	Sat Sep 01 13:25:18 2012 -0400
@@ -0,0 +1,113 @@
+/*
+ * Copyright (c) 2004, 2012, 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.
+ *
+ */
+
+#include "precompiled.hpp"
+#include "assembler_x86.inline.hpp"
+#include "memory/metaspaceShared.hpp"
+
+// Generate the self-patching vtable method:
+//
+// This method will be called (as any other Klass virtual method) with
+// the Klass itself as the first argument.  Example:
+//
+//      oop obj;
+//      int size = obj->klass()->oop_size(this);
+//
+// for which the virtual method call is Klass::oop_size();
+//
+// The dummy method is called with the Klass object as the first
+// operand, and an object as the second argument.
+//
+
+//=====================================================================
+
+// All of the dummy methods in the vtable are essentially identical,
+// differing only by an ordinal constant, and they bear no relationship
+// to the original method which the caller intended. Also, there needs
+// to be 'vtbl_list_size' instances of the vtable in order to
+// differentiate between the 'vtable_list_size' original Klass objects.
+
+#define __ masm->
+
+void MetaspaceShared::generate_vtable_methods(void** vtbl_list,
+                                                   void** vtable,
+                                                   char** md_top,
+                                                   char* md_end,
+                                                   char** mc_top,
+                                                   char* mc_end) {
+
+  intptr_t vtable_bytes = (num_virtuals * vtbl_list_size) * sizeof(void*);
+  *(intptr_t *)(*md_top) = vtable_bytes;
+  *md_top += sizeof(intptr_t);
+  void** dummy_vtable = (void**)*md_top;
+  *vtable = dummy_vtable;
+  *md_top += vtable_bytes;
+
+  // Get ready to generate dummy methods.
+
+  CodeBuffer cb((unsigned char*)*mc_top, mc_end - *mc_top);
+  MacroAssembler* masm = new MacroAssembler(&cb);
+
+  Label common_code;
+  for (int i = 0; i < vtbl_list_size; ++i) {
+    for (int j = 0; j < num_virtuals; ++j) {
+      dummy_vtable[num_virtuals * i + j] = (void*)masm->pc();
+
+      // Load eax with a value indicating vtable/offset pair.
+      // -- bits[ 7..0]  (8 bits) which virtual method in table?
+      // -- bits[12..8]  (5 bits) which virtual method table?
+      // -- must fit in 13-bit instruction immediate field.
+      __ movl(rax, (i << 8) + j);
+      __ jmp(common_code);
+    }
+  }
+
+  __ bind(common_code);
+
+  // Expecting to be called with "thiscall" convections -- the arguments
+  // are on the stack and the "this" pointer is in c_rarg0. In addition, rax
+  // was set (above) to the offset of the method in the table.
+
+  __ push(c_rarg1);                     // save & free register
+  __ push(c_rarg0);                     // save "this"
+  __ mov(c_rarg0, rax);
+  __ shrptr(c_rarg0, 8);                // isolate vtable identifier.
+  __ shlptr(c_rarg0, LogBytesPerWord);
+  __ lea(c_rarg1, ExternalAddress((address)vtbl_list)); // ptr to correct vtable list.
+  __ addptr(c_rarg1, c_rarg0);          // ptr to list entry.
+  __ movptr(c_rarg1, Address(c_rarg1, 0));      // get correct vtable address.
+  __ pop(c_rarg0);                      // restore "this"
+  __ movptr(Address(c_rarg0, 0), c_rarg1);      // update vtable pointer.
+
+  __ andptr(rax, 0x00ff);                       // isolate vtable method index
+  __ shlptr(rax, LogBytesPerWord);
+  __ addptr(rax, c_rarg1);              // address of real method pointer.
+  __ pop(c_rarg1);                      // restore register.
+  __ movptr(rax, Address(rax, 0));      // get real method pointer.
+  __ jmp(rax);                          // jump to the real method.
+
+  __ flush();
+
+  *mc_top = (char*)__ pc();
+}