--- a/hotspot/src/cpu/zero/vm/cppInterpreter_zero.cpp	Thu Apr 29 17:53:58 2010 -0700
+++ b/hotspot/src/cpu/zero/vm/cppInterpreter_zero.cpp	Fri Apr 30 04:27:25 2010 -0700
@@ -833,7 +833,7 @@
   int callee_extra_locals = callee_locals - callee_param_count;
 
   if (interpreter_frame) {
-    intptr_t *locals        = interpreter_frame->sp() + method->max_locals();
+    intptr_t *locals        = interpreter_frame->fp() + method->max_locals();
     interpreterState istate = interpreter_frame->get_interpreterState();
     intptr_t *monitor_base  = (intptr_t*) istate;
     intptr_t *stack_base    = monitor_base - monitor_words;

--- a/hotspot/src/cpu/zero/vm/frame_zero.cpp	Thu Apr 29 17:53:58 2010 -0700
+++ b/hotspot/src/cpu/zero/vm/frame_zero.cpp	Fri Apr 30 04:27:25 2010 -0700
@@ -1,6 +1,6 @@
 /*
  * Copyright 2003-2007 Sun Microsystems, Inc.  All Rights Reserved.
- * Copyright 2007, 2008, 2009 Red Hat, Inc.
+ * Copyright 2007, 2008, 2009, 2010 Red Hat, Inc.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -44,14 +44,14 @@
          "sender should be next Java frame");
   map->clear();
   assert(map->include_argument_oops(), "should be set by clear");
-  return frame(sender_sp(), sp() + 1);
+  return frame(zeroframe()->next(), sender_sp());
 }
 
 frame frame::sender_for_nonentry_frame(RegisterMap *map) const {
   assert(zeroframe()->is_interpreter_frame() ||
          zeroframe()->is_shark_frame() ||
          zeroframe()->is_fake_stub_frame(), "wrong type of frame");
-  return frame(sender_sp(), sp() + 1);
+  return frame(zeroframe()->next(), sender_sp());
 }
 
 frame frame::sender(RegisterMap* map) const {
@@ -172,8 +172,8 @@
   char *valuebuf = buf + buflen;
 
   // Print each word of the frame
-  for (intptr_t *addr = fp(); addr <= sp(); addr++) {
-    int offset = sp() - addr;
+  for (intptr_t *addr = sp(); addr <= fp(); addr++) {
+    int offset = fp() - addr;
 
     // Fill in default values, then try and improve them
     snprintf(fieldbuf, buflen, "word[%d]", offset);

--- a/hotspot/src/cpu/zero/vm/frame_zero.hpp	Thu Apr 29 17:53:58 2010 -0700
+++ b/hotspot/src/cpu/zero/vm/frame_zero.hpp	Fri Apr 30 04:27:25 2010 -0700
@@ -1,6 +1,6 @@
 /*
  * Copyright 2003-2007 Sun Microsystems, Inc.  All Rights Reserved.
- * Copyright 2007, 2008, 2009 Red Hat, Inc.
+ * Copyright 2007, 2008, 2009, 2010 Red Hat, Inc.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -32,17 +32,18 @@
 
   // Constructor
  public:
-  frame(intptr_t* sp, intptr_t* fp);
+  frame(ZeroFrame* zeroframe, intptr_t* sp);
 
-  // The sp of a Zero frame is the address of the highest word in
-  // that frame.  We keep track of the lowest address too, so the
-  // boundaries of the frame are available for debug printing.
  private:
-  intptr_t* _fp;
+  ZeroFrame* _zeroframe;
 
  public:
+  const ZeroFrame *zeroframe() const {
+    return _zeroframe;
+  }
+
   intptr_t* fp() const {
-    return _fp;
+    return (intptr_t *) zeroframe();
   }
 
 #ifdef CC_INTERP
@@ -50,10 +51,6 @@
 #endif // CC_INTERP
 
  public:
-  const ZeroFrame *zeroframe() const {
-    return (ZeroFrame *) sp();
-  }
-
   const EntryFrame *zero_entryframe() const {
     return zeroframe()->as_entry_frame();
   }

--- a/hotspot/src/cpu/zero/vm/frame_zero.inline.hpp	Thu Apr 29 17:53:58 2010 -0700
+++ b/hotspot/src/cpu/zero/vm/frame_zero.inline.hpp	Fri Apr 30 04:27:25 2010 -0700
@@ -1,6 +1,6 @@
 /*
  * Copyright 2003-2007 Sun Microsystems, Inc.  All Rights Reserved.
- * Copyright 2007, 2008, 2009 Red Hat, Inc.
+ * Copyright 2007, 2008, 2009, 2010 Red Hat, Inc.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -26,16 +26,16 @@
 // Constructors
 
 inline frame::frame() {
+  _zeroframe = NULL;
   _sp = NULL;
-  _fp = NULL;
   _pc = NULL;
   _cb = NULL;
   _deopt_state = unknown;
 }
 
-inline frame::frame(intptr_t* sp, intptr_t* fp) {
+inline frame::frame(ZeroFrame* zf, intptr_t* sp) {
+  _zeroframe = zf;
   _sp = sp;
-  _fp = fp;
   switch (zeroframe()->type()) {
   case ZeroFrame::ENTRY_FRAME:
     _pc = StubRoutines::call_stub_return_pc();
@@ -66,7 +66,7 @@
 // Accessors
 
 inline intptr_t* frame::sender_sp() const {
-  return (intptr_t *) zeroframe()->next();
+  return fp() + 1;
 }
 
 inline intptr_t* frame::link() const {
@@ -120,7 +120,7 @@
 // we can distinguish identity and younger/older relationship. NULL
 // represents an invalid (incomparable) frame.
 inline intptr_t* frame::id() const {
-  return sp();
+  return fp();
 }
 
 inline JavaCallWrapper* frame::entry_frame_call_wrapper() const {

--- a/hotspot/src/cpu/zero/vm/javaFrameAnchor_zero.hpp	Thu Apr 29 17:53:58 2010 -0700
+++ b/hotspot/src/cpu/zero/vm/javaFrameAnchor_zero.hpp	Fri Apr 30 04:27:25 2010 -0700
@@ -1,6 +1,6 @@
 /*
  * Copyright 2003-2005 Sun Microsystems, Inc.  All Rights Reserved.
- * Copyright 2007, 2008 Red Hat, Inc.
+ * Copyright 2007, 2008, 2010 Red Hat, Inc.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -23,21 +23,31 @@
  *
  */
 
+ private:
+  ZeroFrame* volatile _last_Java_fp;
+
  public:
   // Each arch must define reset, save, restore
   // These are used by objects that only care about:
   //  1 - initializing a new state (thread creation, javaCalls)
   //  2 - saving a current state (javaCalls)
   //  3 - restoring an old state (javaCalls)
+  // Note that whenever _last_Java_sp != NULL other anchor fields
+  // must be valid.  The profiler apparently depends on this.
 
   void clear() {
     // clearing _last_Java_sp must be first
     _last_Java_sp = NULL;
     // fence?
+    _last_Java_fp = NULL;
     _last_Java_pc = NULL;
   }
 
   void copy(JavaFrameAnchor* src) {
+    set(src->_last_Java_sp, src->_last_Java_pc, src->_last_Java_fp);
+  }
+
+  void set(intptr_t* sp, address pc, ZeroFrame* fp) {
     // In order to make sure the transition state is valid for "this"
     // We must clear _last_Java_sp before copying the rest of the new
     // data
@@ -46,13 +56,14 @@
     // previous version (pd_cache_state) don't NULL _last_Java_sp
     // unless the value is changing
     //
-    if (_last_Java_sp != src->_last_Java_sp)
+    if (_last_Java_sp != sp)
       _last_Java_sp = NULL;
 
-    _last_Java_pc = src->_last_Java_pc;
+    _last_Java_fp = fp;
+    _last_Java_pc = pc;
     // Must be last so profiler will always see valid frame if
     // has_last_frame() is true
-    _last_Java_sp = src->_last_Java_sp;
+    _last_Java_sp = sp;
   }
 
   bool walkable() {
@@ -67,6 +78,6 @@
     return _last_Java_sp;
   }
 
-  void set_last_Java_sp(intptr_t* sp) {
-    _last_Java_sp = sp;
+  ZeroFrame* last_Java_fp() const {
+    return _last_Java_fp;
   }

--- a/hotspot/src/cpu/zero/vm/stack_zero.cpp	Thu Apr 29 17:53:58 2010 -0700
+++ b/hotspot/src/cpu/zero/vm/stack_zero.cpp	Fri Apr 30 04:27:25 2010 -0700
@@ -32,6 +32,7 @@
   // Set up the frame anchor if it isn't already
   bool has_last_Java_frame = thread->has_last_Java_frame();
   if (!has_last_Java_frame) {
+    intptr_t *sp = thread->zero_stack()->sp();
     ZeroFrame *frame = thread->top_zero_frame();
     while (frame) {
       if (frame->is_shark_frame())
@@ -44,13 +45,14 @@
           break;
       }
 
+      sp = ((intptr_t *) frame) + 1;
       frame = frame->next();
     }
 
     if (frame == NULL)
       fatal("unrecoverable stack overflow");
 
-    thread->set_last_Java_frame(frame);
+    thread->set_last_Java_frame(frame, sp);
   }
 
   // Throw the exception
@@ -71,3 +73,9 @@
   if (!has_last_Java_frame)
     thread->reset_last_Java_frame();
 }
+
+#ifndef PRODUCT
+void ZeroStack::zap(int c) {
+  memset(_base, c, available_words() * wordSize);
+}
+#endif // PRODUCT

--- a/hotspot/src/cpu/zero/vm/stack_zero.hpp	Thu Apr 29 17:53:58 2010 -0700
+++ b/hotspot/src/cpu/zero/vm/stack_zero.hpp	Fri Apr 30 04:27:25 2010 -0700
@@ -95,6 +95,9 @@
   static void handle_overflow(TRAPS);
 
  public:
+  void zap(int c) PRODUCT_RETURN;
+
+ public:
   static ByteSize base_offset() {
     return byte_offset_of(ZeroStack, _base);
   }

--- a/hotspot/src/os_cpu/linux_zero/vm/thread_linux_zero.hpp	Thu Apr 29 17:53:58 2010 -0700
+++ b/hotspot/src/os_cpu/linux_zero/vm/thread_linux_zero.hpp	Fri Apr 30 04:27:25 2010 -0700
@@ -68,19 +68,24 @@
 
  public:
   void set_last_Java_frame() {
-    set_last_Java_frame(top_zero_frame());
+    set_last_Java_frame(top_zero_frame(), zero_stack()->sp());
   }
   void reset_last_Java_frame() {
-    set_last_Java_frame(NULL);
+    frame_anchor()->zap();
+  }
+  void set_last_Java_frame(ZeroFrame* fp, intptr_t* sp) {
+    frame_anchor()->set(sp, NULL, fp);
   }
-  void set_last_Java_frame(ZeroFrame* frame) {
-    frame_anchor()->set_last_Java_sp((intptr_t *) frame);
+
+ public:
+  ZeroFrame* last_Java_fp() {
+    return frame_anchor()->last_Java_fp();
   }
 
  private:
   frame pd_last_frame() {
     assert(has_last_Java_frame(), "must have last_Java_sp() when suspended");
-    return frame(last_Java_sp(), zero_stack()->sp());
+    return frame(last_Java_fp(), last_Java_sp());
   }
 
  public: