--- a/c1x4hotspotsrc/HotSpotVM/src/com/sun/hotspot/c1x/VMExitsNative.java	Thu Dec 23 18:13:28 2010 +0100
+++ b/c1x4hotspotsrc/HotSpotVM/src/com/sun/hotspot/c1x/VMExitsNative.java	Thu Dec 23 22:14:31 2010 +0100
@@ -53,6 +53,7 @@
         C1XOptions.DetailedAsserts = false;
         C1XOptions.CommentedAssembly = true;
         C1XOptions.MethodEndBreakpointGuards = 10;
+        C1XOptions.ZapStackOnMethodEntry = true;
     }
 
     @Override

--- a/src/share/vm/c1x/c1x_CodeInstaller.cpp	Thu Dec 23 18:13:28 2010 +0100
+++ b/src/share/vm/c1x/c1x_CodeInstaller.cpp	Thu Dec 23 22:14:31 2010 +0100
@@ -350,6 +350,10 @@
     reexecute = Interpreter::bytecode_should_reexecute(code);
   }
 
+  if (TraceC1X >= 2) {
+    tty->print_cr("Recording scope pc_offset=%d bci=%d frame=%d", pc_offset, bci, frame);
+  }
+
   if (frame != NULL) {
     jint local_count = CiDebugInfo_Frame::numLocals(frame);
     jint expression_count = CiDebugInfo_Frame::numStack(frame);

--- a/src/share/vm/code/nmethod.cpp	Thu Dec 23 18:13:28 2010 +0100
+++ b/src/share/vm/code/nmethod.cpp	Thu Dec 23 22:14:31 2010 +0100
@@ -1099,6 +1099,12 @@
 
 ScopeDesc* nmethod::scope_desc_at(address pc) {
   PcDesc* pd = pc_desc_at(pc);
+#ifdef ASSERT
+  if (pd == NULL) {
+    tty->print_cr(err_msg("Missing scope at relative pc %d of method %s", pc - code_begin(), this->method()->name()->as_C_string()));
+    print_pcs();
+  }
+#endif
   guarantee(pd != NULL, "scope must be present");
   return new ScopeDesc(this, pd->scope_decode_offset(),
                        pd->obj_decode_offset(), pd->should_reexecute(),

--- a/src/share/vm/code/nmethod.hpp	Thu Dec 23 18:13:28 2010 +0100
+++ b/src/share/vm/code/nmethod.hpp	Thu Dec 23 22:14:31 2010 +0100
@@ -579,7 +579,10 @@
   // Deopt
   // Return true is the PC is one would expect if the frame is being deopted.
   bool is_deopt_pc      (address pc) { return is_deopt_entry(pc) || is_deopt_mh_entry(pc); }
-  bool is_deopt_entry   (address pc) { return pc == deopt_handler_begin(); }
+
+  // (tw) When using C1X, the address might be off by 5 (because this is the size of the call instruction.
+  // (tw) TODO: Replace this by a more general mechanism.
+  bool is_deopt_entry   (address pc) { return pc == deopt_handler_begin() || (UseC1X && pc == deopt_handler_begin() + 5); }
   bool is_deopt_mh_entry(address pc) { return pc == deopt_mh_handler_begin(); }
   // Accessor/mutator for the original pc of a frame before a frame was deopted.
   address get_original_pc(const frame* fr) { return *orig_pc_addr(fr); }

--- a/src/share/vm/code/pcDesc.cpp	Thu Dec 23 18:13:28 2010 +0100
+++ b/src/share/vm/code/pcDesc.cpp	Thu Dec 23 22:14:31 2010 +0100
@@ -40,7 +40,7 @@
 void PcDesc::print(nmethod* code) {
 #ifndef PRODUCT
   ResourceMark rm;
-  tty->print_cr("PcDesc(pc=0x%lx offset=%x):", real_pc(code), pc_offset());
+  tty->print_cr("PcDesc(pc=0x%lx offset=%d):", real_pc(code), pc_offset());
 
   if (scope_decode_offset() == DebugInformationRecorder::serialized_null) {
     return;

--- a/src/share/vm/runtime/deoptimization.cpp	Thu Dec 23 18:13:28 2010 +0100
+++ b/src/share/vm/runtime/deoptimization.cpp	Thu Dec 23 22:14:31 2010 +0100
@@ -114,6 +114,10 @@
   // the vframeArray is created.
   //
 
+  if (TraceDeoptimization) {
+    tty->print_cr("fetching unroll info");
+  }
+
   // Allocate our special deoptimization ResourceMark
   DeoptResourceMark* dmark = new DeoptResourceMark(thread);
   assert(thread->deopt_mark() == NULL, "Pending deopt!");

--- a/src/share/vm/runtime/stackValue.cpp	Thu Dec 23 18:13:28 2010 +0100
+++ b/src/share/vm/runtime/stackValue.cpp	Thu Dec 23 22:14:31 2010 +0100
@@ -114,6 +114,14 @@
          val = (oop)NULL;
       }
 #endif
+#ifndef PRODUCT
+      if (!val->is_oop()) {
+        tty->print_cr("found wrong oop %x at location:", val);
+        sv->print();
+        tty->print_cr("");
+        tty->print_cr("one less %d; one more %d", (*(((oop *)value_addr) - 1))->is_oop(), (*(((oop *)value_addr) + 1))->is_oop());
+      }
+#endif
       Handle h(val); // Wrap a handle around the oop
       return new StackValue(h);
     }

--- a/src/share/vm/runtime/vframe_hp.cpp	Thu Dec 23 18:13:28 2010 +0100
+++ b/src/share/vm/runtime/vframe_hp.cpp	Thu Dec 23 22:14:31 2010 +0100
@@ -52,6 +52,12 @@
     }
   }
 
+  if (TraceDeoptimization) {
+    tty->print_cr("bci=%d length=%d", this->bci(), length);
+    tty->print_cr(err_msg("method name = %s", this->method()->name()->as_C_string()));
+    tty->print_cr("relative pc=%d", this->fr().pc() - this->nm()->code_begin());
+  }
+
   for( int i = 0; i < length; i++ ) {
     result->add( create_stack_value(scv_list->at(i)) );
   }