--- a/hotspot/agent/src/share/classes/sun/jvm/hotspot/runtime/StubRoutines.java	Mon Jan 31 17:48:21 2011 -0800
+++ b/hotspot/agent/src/share/classes/sun/jvm/hotspot/runtime/StubRoutines.java	Tue Feb 01 03:38:44 2011 -0800
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2000, 2009, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2000, 2011, 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
@@ -31,8 +31,7 @@
 /** Very minimal port for now to get frames working */
 
 public class StubRoutines {
-  private static AddressField      callStubReturnAddressField;
-  private static AddressField      callStubCompiledReturnAddressField;
+  private static AddressField callStubReturnAddressField;
 
   static {
     VM.registerVMInitializedObserver(new Observer() {
@@ -44,20 +43,7 @@
 
   private static synchronized void initialize(TypeDataBase db) {
     Type type = db.lookupType("StubRoutines");
-
     callStubReturnAddressField = type.getAddressField("_call_stub_return_address");
-    // Only some platforms have specific return from compiled to call_stub
-    try {
-      type = db.lookupType("StubRoutines::x86");
-      if (type != null) {
-        callStubCompiledReturnAddressField = type.getAddressField("_call_stub_compiled_return");
-      }
-    } catch (RuntimeException re) {
-      callStubCompiledReturnAddressField = null;
-    }
-    if (callStubCompiledReturnAddressField == null && VM.getVM().getCPU().equals("x86")) {
-      throw new InternalError("Missing definition for _call_stub_compiled_return");
-    }
   }
 
   public StubRoutines() {
@@ -65,20 +51,10 @@
 
   public boolean returnsToCallStub(Address returnPC) {
     Address addr = callStubReturnAddressField.getValue();
-    boolean result = false;
-    if (addr == null) {
-      result = (addr == returnPC);
-    } else {
-      result = addr.equals(returnPC);
-    }
-    if (result || callStubCompiledReturnAddressField == null ) return result;
-    // Could be a return to compiled code return point
-    addr = callStubCompiledReturnAddressField.getValue();
     if (addr == null) {
       return (addr == returnPC);
     } else {
       return (addr.equals(returnPC));
     }
-
   }
 }

--- a/hotspot/src/cpu/x86/vm/cppInterpreter_x86.cpp	Mon Jan 31 17:48:21 2011 -0800
+++ b/hotspot/src/cpu/x86/vm/cppInterpreter_x86.cpp	Tue Feb 01 03:38:44 2011 -0800
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2007, 2010, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2007, 2011, 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
@@ -1899,8 +1899,6 @@
   Label do_double;
   Label done_conv;
 
-  address compiled_entry = __ pc();
-
   // The FPU stack is clean if UseSSE >= 2 but must be cleaned in other cases
   if (UseSSE < 2) {
     __ lea(state, Address(rbp,  -(int)sizeof(BytecodeInterpreter)));
@@ -1934,15 +1932,7 @@
     __ jmp(done_conv);
   }
 
-#if 0
-  // emit a sentinel we can test for when converting an interpreter
-  // entry point to a compiled entry point.
-  __ a_long(Interpreter::return_sentinel);
-  __ a_long((int)compiled_entry);
-#endif
-
   // Return point to interpreter from compiled/native method
-
   InternalAddress return_from_native_method(__ pc());
 
   __ bind(done_conv);

--- a/hotspot/src/cpu/x86/vm/interpreter_x86.hpp	Mon Jan 31 17:48:21 2011 -0800
+++ b/hotspot/src/cpu/x86/vm/interpreter_x86.hpp	Tue Feb 01 03:38:44 2011 -0800
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1997, 2010, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1997, 2011, 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
@@ -26,14 +26,6 @@
 #define CPU_X86_VM_INTERPRETER_X86_HPP
 
  public:
-
-  // Sentinel placed in the code for interpreter returns so
-  // that i2c adapters and osr code can recognize an interpreter
-  // return address and convert the return to a specialized
-  // block of code to handle compiedl return values and cleaning
-  // the fpu stack.
-  static const int return_sentinel;
-
   static Address::ScaleFactor stackElementScale() { return Address::times_4; }
 
   // Offset from rsp (which points to the last stack element)

--- a/hotspot/src/cpu/x86/vm/interpreter_x86_32.cpp	Mon Jan 31 17:48:21 2011 -0800
+++ b/hotspot/src/cpu/x86/vm/interpreter_x86_32.cpp	Tue Feb 01 03:38:44 2011 -0800
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1997, 2010, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1997, 2011, 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
@@ -51,9 +51,6 @@
 
 #define __ _masm->
 
-// Initialize the sentinel used to distinguish an interpreter return address.
-const int Interpreter::return_sentinel = 0xfeedbeed;
-
 //------------------------------------------------------------------------------------------------------------------------
 
 address AbstractInterpreterGenerator::generate_slow_signature_handler() {

--- a/hotspot/src/cpu/x86/vm/sharedRuntime_x86_32.cpp	Mon Jan 31 17:48:21 2011 -0800
+++ b/hotspot/src/cpu/x86/vm/sharedRuntime_x86_32.cpp	Tue Feb 01 03:38:44 2011 -0800
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2010, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2011, 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
@@ -660,25 +660,6 @@
                             int comp_args_on_stack,
                             const BasicType *sig_bt,
                             const VMRegPair *regs) {
-  // we're being called from the interpreter but need to find the
-  // compiled return entry point.  The return address on the stack
-  // should point at it and we just need to pull the old value out.
-  // load up the pointer to the compiled return entry point and
-  // rewrite our return pc. The code is arranged like so:
-  //
-  // .word Interpreter::return_sentinel
-  // .word address_of_compiled_return_point
-  // return_entry_point: blah_blah_blah
-  //
-  // So we can find the appropriate return point by loading up the word
-  // just prior to the current return address we have on the stack.
-  //
-  // We will only enter here from an interpreted frame and never from after
-  // passing thru a c2i. Azul allowed this but we do not. If we lose the
-  // race and use a c2i we will remain interpreted for the race loser(s).
-  // This removes all sorts of headaches on the x86 side and also eliminates
-  // the possibility of having c2i -> i2c -> c2i -> ... endless transitions.
-
 
   // Note: rsi contains the senderSP on entry. We must preserve it since
   // we may do a i2c -> c2i transition if we lose a race where compiled
@@ -687,40 +668,6 @@
   // Pick up the return address
   __ movptr(rax, Address(rsp, 0));
 
-  // If UseSSE >= 2 then no cleanup is needed on the return to the
-  // interpreter so skip fixing up the return entry point unless
-  // VerifyFPU is enabled.
-  if (UseSSE < 2 || VerifyFPU) {
-    Label skip, chk_int;
-    // If we were called from the call stub we need to do a little bit different
-    // cleanup than if the interpreter returned to the call stub.
-
-    ExternalAddress stub_return_address(StubRoutines::_call_stub_return_address);
-    __ cmpptr(rax, stub_return_address.addr());
-    __ jcc(Assembler::notEqual, chk_int);
-    assert(StubRoutines::x86::get_call_stub_compiled_return() != NULL, "must be set");
-    __ lea(rax, ExternalAddress(StubRoutines::x86::get_call_stub_compiled_return()));
-    __ jmp(skip);
-
-    // It must be the interpreter since we never get here via a c2i (unlike Azul)
-
-    __ bind(chk_int);
-#ifdef ASSERT
-    {
-      Label ok;
-      __ cmpl(Address(rax, -2*wordSize), Interpreter::return_sentinel);
-      __ jcc(Assembler::equal, ok);
-      __ int3();
-      __ bind(ok);
-    }
-#endif // ASSERT
-    __ movptr(rax, Address(rax, -wordSize));
-    __ bind(skip);
-  }
-
-  // rax, now contains the compiled return entry point which will do an
-  // cleanup needed for the return from compiled to interpreted.
-
   // Must preserve original SP for loading incoming arguments because
   // we need to align the outgoing SP for compiled code.
   __ movptr(rdi, rsp);

--- a/hotspot/src/cpu/x86/vm/sharedRuntime_x86_64.cpp	Mon Jan 31 17:48:21 2011 -0800
+++ b/hotspot/src/cpu/x86/vm/sharedRuntime_x86_64.cpp	Tue Feb 01 03:38:44 2011 -0800
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2010, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2011, 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
@@ -610,14 +610,6 @@
                             const BasicType *sig_bt,
                             const VMRegPair *regs) {
 
-  //
-  // We will only enter here from an interpreted frame and never from after
-  // passing thru a c2i. Azul allowed this but we do not. If we lose the
-  // race and use a c2i we will remain interpreted for the race loser(s).
-  // This removes all sorts of headaches on the x86 side and also eliminates
-  // the possibility of having c2i -> i2c -> c2i -> ... endless transitions.
-
-
   // Note: r13 contains the senderSP on entry. We must preserve it since
   // we may do a i2c -> c2i transition if we lose a race where compiled
   // code goes non-entrant while we get args ready.
@@ -627,6 +619,7 @@
   // save code can segv when fxsave instructions find improperly
   // aligned stack pointer.
 
+  // Pick up the return address
   __ movptr(rax, Address(rsp, 0));
 
   // Must preserve original SP for loading incoming arguments because

--- a/hotspot/src/cpu/x86/vm/stubGenerator_x86_32.cpp	Mon Jan 31 17:48:21 2011 -0800
+++ b/hotspot/src/cpu/x86/vm/stubGenerator_x86_32.cpp	Tue Feb 01 03:38:44 2011 -0800
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1999, 2010, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1999, 2011, 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
@@ -240,9 +240,30 @@
     BLOCK_COMMENT("call_stub_return_address:");
     return_address = __ pc();
 
-    Label common_return;
+#ifdef COMPILER2
+    {
+      Label L_skip;
+      if (UseSSE >= 2) {
+        __ verify_FPU(0, "call_stub_return");
+      } else {
+        for (int i = 1; i < 8; i++) {
+          __ ffree(i);
+        }
 
-    __ BIND(common_return);
+        // UseSSE <= 1 so double result should be left on TOS
+        __ movl(rsi, result_type);
+        __ cmpl(rsi, T_DOUBLE);
+        __ jcc(Assembler::equal, L_skip);
+        if (UseSSE == 0) {
+          // UseSSE == 0 so float result should be left on TOS
+          __ cmpl(rsi, T_FLOAT);
+          __ jcc(Assembler::equal, L_skip);
+        }
+        __ ffree(0);
+      }
+      __ BIND(L_skip);
+    }
+#endif // COMPILER2
 
     // store result depending on type
     // (everything that is not T_LONG, T_FLOAT or T_DOUBLE is treated as T_INT)
@@ -305,37 +326,6 @@
     }
     __ jmp(exit);
 
-    // If we call compiled code directly from the call stub we will
-    // need to adjust the return back to the call stub to a specialized
-    // piece of code that can handle compiled results and cleaning the fpu
-    // stack. compiled code will be set to return here instead of the
-    // return above that handles interpreter returns.
-
-    BLOCK_COMMENT("call_stub_compiled_return:");
-    StubRoutines::x86::set_call_stub_compiled_return( __ pc());
-
-#ifdef COMPILER2
-    if (UseSSE >= 2) {
-      __ verify_FPU(0, "call_stub_compiled_return");
-    } else {
-      for (int i = 1; i < 8; i++) {
-        __ ffree(i);
-      }
-
-      // UseSSE <= 1 so double result should be left on TOS
-      __ movl(rsi, result_type);
-      __ cmpl(rsi, T_DOUBLE);
-      __ jcc(Assembler::equal, common_return);
-      if (UseSSE == 0) {
-        // UseSSE == 0 so float result should be left on TOS
-        __ cmpl(rsi, T_FLOAT);
-        __ jcc(Assembler::equal, common_return);
-      }
-      __ ffree(0);
-    }
-#endif /* COMPILER2 */
-    __ jmp(common_return);
-
     return start;
   }
 

--- a/hotspot/src/cpu/x86/vm/stubRoutines_x86_32.cpp	Mon Jan 31 17:48:21 2011 -0800
+++ b/hotspot/src/cpu/x86/vm/stubRoutines_x86_32.cpp	Tue Feb 01 03:38:44 2011 -0800
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1997, 2010, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1997, 2011, 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
@@ -39,6 +39,5 @@
 // Implementation of the platform-specific part of StubRoutines - for
 // a description of how to extend it, see the stubRoutines.hpp file.
 
-address StubRoutines::x86::_verify_mxcsr_entry        = NULL;
-address StubRoutines::x86::_verify_fpu_cntrl_wrd_entry= NULL;
-address StubRoutines::x86::_call_stub_compiled_return = NULL;
+address StubRoutines::x86::_verify_mxcsr_entry         = NULL;
+address StubRoutines::x86::_verify_fpu_cntrl_wrd_entry = NULL;

--- a/hotspot/src/cpu/x86/vm/stubRoutines_x86_32.hpp	Mon Jan 31 17:48:21 2011 -0800
+++ b/hotspot/src/cpu/x86/vm/stubRoutines_x86_32.hpp	Tue Feb 01 03:38:44 2011 -0800
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1997, 2010, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1997, 2011, 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
@@ -44,24 +44,14 @@
  friend class VMStructs;
 
  private:
-  // If we call compiled code directly from the call stub we will
-  // need to adjust the return back to the call stub to a specialized
-  // piece of code that can handle compiled results and cleaning the fpu
-  // stack. The variable holds that location.
-  static address _call_stub_compiled_return;
   static address _verify_mxcsr_entry;
   static address _verify_fpu_cntrl_wrd_entry;
-  static jint    _mxcsr_std;
 
  public:
   static address verify_mxcsr_entry()                        { return _verify_mxcsr_entry; }
   static address verify_fpu_cntrl_wrd_entry()                { return _verify_fpu_cntrl_wrd_entry; }
-
-  static address get_call_stub_compiled_return()             { return _call_stub_compiled_return; }
-  static void set_call_stub_compiled_return(address ret)     { _call_stub_compiled_return = ret; }
 };
 
-  static bool    returns_to_call_stub(address return_pc)     { return (return_pc == _call_stub_return_address) ||
-                                                                       return_pc == x86::get_call_stub_compiled_return(); }
+  static bool    returns_to_call_stub(address return_pc)     { return return_pc == _call_stub_return_address; }
 
 #endif // CPU_X86_VM_STUBROUTINES_X86_32_HPP

--- a/hotspot/src/cpu/x86/vm/templateInterpreter_x86_32.cpp	Mon Jan 31 17:48:21 2011 -0800
+++ b/hotspot/src/cpu/x86/vm/templateInterpreter_x86_32.cpp	Tue Feb 01 03:38:44 2011 -0800
@@ -177,9 +177,7 @@
 
 address TemplateInterpreterGenerator::generate_return_entry_for(TosState state, int step) {
   TosState incoming_state = state;
-
-  Label interpreter_entry;
-  address compiled_entry = __ pc();
+  address entry = __ pc();
 
 #ifdef COMPILER2
   // The FPU stack is clean if UseSSE >= 2 but must be cleaned in other cases
@@ -197,14 +195,6 @@
     __ MacroAssembler::verify_FPU(0, "generate_return_entry_for compiled");
   }
 
-  __ jmp(interpreter_entry, relocInfo::none);
-  // emit a sentinel we can test for when converting an interpreter
-  // entry point to a compiled entry point.
-  __ a_long(Interpreter::return_sentinel);
-  __ a_long((int)compiled_entry);
-  address entry = __ pc();
-  __ bind(interpreter_entry);
-
   // In SSE mode, interpreter returns FP results in xmm0 but they need
   // to end up back on the FPU so it can operate on them.
   if (incoming_state == ftos && UseSSE >= 1) {

--- a/hotspot/src/cpu/x86/vm/templateInterpreter_x86_64.cpp	Mon Jan 31 17:48:21 2011 -0800
+++ b/hotspot/src/cpu/x86/vm/templateInterpreter_x86_64.cpp	Tue Feb 01 03:38:44 2011 -0800
@@ -190,13 +190,7 @@
 }
 
 
-address TemplateInterpreterGenerator::generate_return_entry_for(TosState state,
-                                                                int step) {
-
-  // amd64 doesn't need to do anything special about compiled returns
-  // to the interpreter so the code that exists on x86 to place a sentinel
-  // here and the specialized cleanup code is not needed here.
-
+address TemplateInterpreterGenerator::generate_return_entry_for(TosState state, int step) {
   address entry = __ pc();
 
   // Restore stack bottom in case i2c adjusted stack

--- a/hotspot/src/cpu/x86/vm/templateTable_x86_32.cpp	Mon Jan 31 17:48:21 2011 -0800
+++ b/hotspot/src/cpu/x86/vm/templateTable_x86_32.cpp	Tue Feb 01 03:38:44 2011 -0800
@@ -1710,39 +1710,6 @@
       __ pop(rdi);                               // get return address
       __ mov(rsp, rdx);                          // set sp to sender sp
 
-
-      Label skip;
-      Label chkint;
-
-      // The interpreter frame we have removed may be returning to
-      // either the callstub or the interpreter. Since we will
-      // now be returning from a compiled (OSR) nmethod we must
-      // adjust the return to the return were it can handler compiled
-      // results and clean the fpu stack. This is very similar to
-      // what a i2c adapter must do.
-
-      // Are we returning to the call stub?
-
-      __ cmp32(rdi, ExternalAddress(StubRoutines::_call_stub_return_address));
-      __ jcc(Assembler::notEqual, chkint);
-
-      // yes adjust to the specialized call stub  return.
-      assert(StubRoutines::x86::get_call_stub_compiled_return() != NULL, "must be set");
-      __ lea(rdi, ExternalAddress(StubRoutines::x86::get_call_stub_compiled_return()));
-      __ jmp(skip);
-
-      __ bind(chkint);
-
-      // Are we returning to the interpreter? Look for sentinel
-
-      __ cmpl(Address(rdi, -2*wordSize), Interpreter::return_sentinel);
-      __ jcc(Assembler::notEqual, skip);
-
-      // Adjust to compiled return back to interpreter
-
-      __ movptr(rdi, Address(rdi, -wordSize));
-      __ bind(skip);
-
       // Align stack pointer for compiled code (note that caller is
       // responsible for undoing this fixup by remembering the old SP
       // in an rbp,-relative location)

--- a/hotspot/src/cpu/zero/vm/stubRoutines_zero.cpp	Mon Jan 31 17:48:21 2011 -0800
+++ b/hotspot/src/cpu/zero/vm/stubRoutines_zero.cpp	Tue Feb 01 03:38:44 2011 -0800
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2010, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2011, Oracle and/or its affiliates. All rights reserved.
  * Copyright 2008, 2009 Red Hat, Inc.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
@@ -30,7 +30,3 @@
 #ifdef TARGET_OS_FAMILY_linux
 # include "thread_linux.inline.hpp"
 #endif
-
-#ifdef IA32
-address StubRoutines::x86::_call_stub_compiled_return = NULL;
-#endif // IA32

--- a/hotspot/src/cpu/zero/vm/stubRoutines_zero.hpp	Mon Jan 31 17:48:21 2011 -0800
+++ b/hotspot/src/cpu/zero/vm/stubRoutines_zero.hpp	Tue Feb 01 03:38:44 2011 -0800
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2010, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2011, Oracle and/or its affiliates. All rights reserved.
  * Copyright 2007, 2008, 2009, 2010 Red Hat, Inc.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
@@ -48,13 +48,4 @@
     method_handles_adapters_code_size = 0
   };
 
-#ifdef IA32
-  class x86 {
-    friend class VMStructs;
-
-   private:
-    static address _call_stub_compiled_return;
-  };
-#endif // IA32
-
 #endif // CPU_ZERO_VM_STUBROUTINES_ZERO_HPP

--- a/hotspot/src/share/vm/runtime/vmStructs.cpp	Mon Jan 31 17:48:21 2011 -0800
+++ b/hotspot/src/share/vm/runtime/vmStructs.cpp	Tue Feb 01 03:38:44 2011 -0800
@@ -729,7 +729,6 @@
   /***********************************/                                                                                              \
                                                                                                                                      \
      static_field(StubRoutines,                _call_stub_return_address,                     address)                               \
-     IA32_ONLY(static_field(StubRoutines::x86,_call_stub_compiled_return,                     address))                              \
                                                                                                                                      \
   /***************************************/                                                                                          \
   /* PcDesc and other compiled code info */                                                                                          \