--- a/src/share/vm/classfile/classFileParser.cpp	Mon Feb 04 23:53:10 2013 -0500
+++ b/src/share/vm/classfile/classFileParser.cpp	Tue Feb 05 00:59:40 2013 -0800
@@ -1947,6 +1947,8 @@
   u2** localvariable_type_table_start;
   u2 method_parameters_length = 0;
   u1* method_parameters_data = NULL;
+  bool method_parameters_seen = false;
+  bool method_parameters_four_byte_flags;
   bool parsed_code_attribute = false;
   bool parsed_checked_exceptions_attribute = false;
   bool parsed_stackmap_attribute = false;
@@ -2157,21 +2159,31 @@
                                      method_attribute_length,
                                      cp, CHECK_(nullHandle));
     } else if (method_attribute_name == vmSymbols::tag_method_parameters()) {
+      // reject multiple method parameters
+      if (method_parameters_seen) {
+        classfile_parse_error("Multiple MethodParameters attributes in class file %s", CHECK_(nullHandle));
+      }
+      method_parameters_seen = true;
       method_parameters_length = cfs->get_u1_fast();
       // Track the actual size (note: this is written for clarity; a
       // decent compiler will CSE and constant-fold this into a single
       // expression)
-      u2 actual_size = 1;
+      // Use the attribute length to figure out the size of flags
+      if (method_attribute_length == (method_parameters_length * 6u) + 1u) {
+        method_parameters_four_byte_flags = true;
+      } else if (method_attribute_length == (method_parameters_length * 4u) + 1u) {
+        method_parameters_four_byte_flags = false;
+      } else {
+        classfile_parse_error(
+          "Invalid MethodParameters method attribute length %u in class file",
+          method_attribute_length, CHECK_(nullHandle));
+      }
       method_parameters_data = cfs->get_u1_buffer();
-      actual_size += 2 * method_parameters_length;
       cfs->skip_u2_fast(method_parameters_length);
-      actual_size += 4 * method_parameters_length;
-      cfs->skip_u4_fast(method_parameters_length);
-      // Enforce attribute length
-      if (method_attribute_length != actual_size) {
-        classfile_parse_error(
-          "Invalid MethodParameters method attribute length %u in class file %s",
-          method_attribute_length, CHECK_(nullHandle));
+      if (method_parameters_four_byte_flags) {
+        cfs->skip_u4_fast(method_parameters_length);
+      } else {
+        cfs->skip_u2_fast(method_parameters_length);
       }
       // ignore this attribute if it cannot be reflected
       if (!SystemDictionary::Parameter_klass_loaded())
@@ -2316,15 +2328,16 @@
   // Copy method parameters
   if (method_parameters_length > 0) {
     MethodParametersElement* elem = m->constMethod()->method_parameters_start();
-    for(int i = 0; i < method_parameters_length; i++) {
-      elem[i].name_cp_index =
-        Bytes::get_Java_u2(method_parameters_data);
+    for (int i = 0; i < method_parameters_length; i++) {
+      elem[i].name_cp_index = Bytes::get_Java_u2(method_parameters_data);
       method_parameters_data += 2;
-      u4 flags = Bytes::get_Java_u4(method_parameters_data);
-      // This caused an alignment fault on Sparc, if flags was a u4
-      elem[i].flags_lo = extract_low_short_from_int(flags);
-      elem[i].flags_hi = extract_high_short_from_int(flags);
-      method_parameters_data += 4;
+      if (method_parameters_four_byte_flags) {
+        elem[i].flags = Bytes::get_Java_u4(method_parameters_data);
+        method_parameters_data += 4;
+      } else {
+        elem[i].flags = Bytes::get_Java_u2(method_parameters_data);
+        method_parameters_data += 2;
+      }
     }
   }
 

--- a/src/share/vm/classfile/stackMapFrame.hpp	Mon Feb 04 23:53:10 2013 -0500
+++ b/src/share/vm/classfile/stackMapFrame.hpp	Tue Feb 05 00:59:40 2013 -0800
@@ -178,7 +178,7 @@
 #ifdef DEBUG
     // Put bogus type to indicate it's no longer valid.
     if (_stack_mark != -1) {
-      for (int i = _stack_mark; i >= _stack_size; --i) {
+      for (int i = _stack_mark - 1; i >= _stack_size; --i) {
         _stack[i] = VerificationType::bogus_type();
       }
     }

--- a/src/share/vm/oops/constMethod.hpp	Mon Feb 04 23:53:10 2013 -0500
+++ b/src/share/vm/oops/constMethod.hpp	Tue Feb 05 00:59:40 2013 -0800
@@ -122,12 +122,7 @@
 class MethodParametersElement VALUE_OBJ_CLASS_SPEC {
  public:
   u2 name_cp_index;
-  // This has to happen, otherwise it will cause SIGBUS from a
-  // misaligned u4 on some architectures (ie SPARC)
-  // because MethodParametersElements are only aligned mod 2
-  // within the ConstMethod container  u2 flags_hi;
-  u2 flags_hi;
-  u2 flags_lo;
+  u2 flags;
 };
 
 class KlassSizeStats;

--- a/src/share/vm/prims/jvm.cpp	Mon Feb 04 23:53:10 2013 -0500
+++ b/src/share/vm/prims/jvm.cpp	Tue Feb 05 00:59:40 2013 -0800
@@ -1620,7 +1620,7 @@
       // For a 0 index, give a NULL symbol
       Symbol* const sym = 0 != params[i].name_cp_index ?
         mh->constants()->symbol_at(params[i].name_cp_index) : NULL;
-      int flags = build_int_from_shorts(params[i].flags_lo, params[i].flags_hi);
+      int flags = params[i].flags;
       oop param = Reflection::new_parameter(reflected_method, i, sym,
                                             flags, CHECK_NULL);
       result->obj_at_put(i, param);

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/test/runtime/8007475/StackMapFrameTest.java	Tue Feb 05 00:59:40 2013 -0800
@@ -0,0 +1,41 @@
+/*
+ * Copyright (c) 2013, 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 8007475
+ * @summary Test memory stomp in stack map test
+ * @run main/othervm -XX:+IgnoreUnrecognizedVMOptions -XX:+UseMallocOnly StackMapFrameTest
+ */
+public class StackMapFrameTest {
+
+  public static void foo() {
+    Object o = new Object();
+  }
+
+  public static void main(String args[]) {
+    for (int i = 0; i < 25000; i++) {
+      foo();
+    }
+  }
+}