compiledIC.hpp

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/* Copyright 1994 - 1996 LongView Technologies L.L.C. $Revision: 1.23 $ */
/* Copyright (c) 2006, Sun Microsystems, Inc.
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#ifdef DELTA_COMPILER

// ICs describe the interface to a send in an nmethod.
// A IC can either describe:
//  - an inline cache for a Delta send (isDeltaSend() == true), or
//  - a primitive call                  (isPrimCall() == true).
//
//
// The memory layout of a Delta send (inline cache) is:
//  (offsets from return address)
// -5: call { _icLookupStub     (if not filled)
//          | nmethod address   (if filled with compiled    method)
//          | pic entry point}  (if filled with PIC/MIC)
//                              <--- CompiledIC* pointers point here
//  0: test reg,                <--- dummy test instruction used to hold ic info
//  1: ic info
//  5: ...                      <--- first instruction after move
//
//
// The memory layout of a primitive call is (offsets from return address):
//
// -5: call ...
//                              <--- PrimitiveIC* pointers point here
//  0: test reg,                <--- dummy test instruction used to hold ic info (only if NLR is possible)
//  1: ic info
//  5: ...                      <--- first instruction after move
//
//
// IC info layout (see als IC_Info for layout constants)
//
// [NLR offset|flags]           32bit immediate of the dummy test instruction
//  31.......8|7...0
//
// The NLR offset is a signed int, the NLR target destination is computed
// from the (call's) return address + NLR offset.
//
// Calling nmethods through a jump table will cost 10% of the total execution speed
// (data provided by Urs 4-21-95)


class AbstractCompiledIC: public NativeCall {
 public:
   char* NLR_testcode() const           { return ic_info_at(next_instruction_address())->NLR_target(); }
   
   // returns the beginning of the inline cache. 
   char* begin_addr() const             { return instruction_address(); }
};


// Flags

const int dirty_send_bit_no             = 0;
const int optimized_bit_no              = 1;
const int uninlinable_bit_no            = 2;
const int super_send_bit_no             = 3;
const int megamorphic_bit_no            = 4;
const int receiver_static_bit_no        = 5;


// CompiledIC isn't a real object; the 'this' pointer points into the compiled code
// (more precisely, it's the same as the return address of the callee)

class CompiledIC: public AbstractCompiledIC {
 protected:
  int compiler_info() const             { return ic_info_at(next_instruction_address())->flags(); }
  void set_compiler_info(int info)      { ic_info_at(next_instruction_address())->set_flags(info); }

 public:
  // lookup routines for empty inline cache
  static char* normalLookupRoutine();
  static char* superLookupRoutine();

  // conversion (machine PC to CompiledIC*)
  friend CompiledIC* CompiledIC_from_return_addr(char* return_addr);
  friend CompiledIC* CompiledIC_from_relocInfo(char* displacement_address);

  // Accessors

  // isDirty() --> has had misses
  bool isDirty() const                  { return isSet(compiler_info(), dirty_send_bit_no); }
  void setDirty()                       { set_compiler_info(addNth(compiler_info(), dirty_send_bit_no)); }

  // isOptimized() --> nmethods called from here should be optimized
  bool isOptimized() const              { return isSet(compiler_info(), optimized_bit_no); }    
  void setOptimized()                   { set_compiler_info(addNth(compiler_info(), optimized_bit_no)); }
  void resetOptimized()                 { set_compiler_info(subNth(compiler_info(), optimized_bit_no)); }

  // isUninlinable() --> compiler says don't try to inline this send
  bool isUninlinable() const            { return isSet(compiler_info(), uninlinable_bit_no); }
  
  // isSuperSend() --> send is a super send
  bool isSuperSend() const              { return isSet(compiler_info(), super_send_bit_no); }

  // isMegamorphic() --> send is megamorphic
  bool isMegamorphic() const            { return isSet(compiler_info(), megamorphic_bit_no); }  
  void setMegamorphic()                 { set_compiler_info(addNth(compiler_info(), megamorphic_bit_no)); }

  // isReceiverStatic() --> receiver klass is known statically (connect to verifiedEntryPoint)
  bool isReceiverStatic() const         { return isSet(compiler_info(), receiver_static_bit_no); }      
  void setReceiverStatic()              { set_compiler_info(addNth(compiler_info(), receiver_static_bit_no)); }

  bool wasNeverExecuted() const;

  InterpretedIC* inlineCache() const;   // corresponding source-level inline cache (NULL if none, e.g. perform)
  PIC*  pic() const;                    // NULL if 0 or 1 targets
    
  // returns the first address after this primitive ic
  char* end_addr()                      { return ic_info_at(next_instruction_address())->next_instruction_address(); }

  // sets the destination of the call instruction
  void set_call_destination(char* entry_point);

  // Does a lookup in the receiver and patches the inline cache
  char* normalLookup(oop receiver);
  char* superLookup (oop receiver);

  // Returns the class that holds the current method
  klassOop sending_method_holder();

  // replace appropriate target (with key nm->key) by nm
  void replace(nmethod* nm);    
  
 public:
  symbolOop     selector() const;
  bool          is_empty() const;
  bool          is_monomorphic() const;
  bool          is_polymorphic() const;
  bool          is_megamorphic() const;
  
  nmethod*      target() const;         // directly called nmethod or NULL if none/PIC
  klassOop      targetKlass() const;    // klass of compiled or interpreted target;
                                        // can only call if single target
  int           ntargets() const;       // number of targets in inline cache or PIC
  klassOop      get_klass(int i) const; // receiver klass of ith target (i=0..ntargets()-1)
  
  // returns the lookup key for PIC index
  LookupKey*    key(int which, bool is_normal_send) const;
  void          reset_jump_addr();
  void          link(PIC* s);
  void          clear();                // clear inline cache
  void          cleanup();              // cleanup inline cache

  bool verify();
  void print();
};

class PrimitiveIC: public AbstractCompiledIC {
 public:
  // returns the primitive descriptor (based on the destination of the call).
  primitive_desc* primitive();

  // conversion (machine PC to PrimitiveIC*)
  friend PrimitiveIC* PrimitiveIC_from_return_addr(char* return_addr);
  friend PrimitiveIC* PrimitiveIC_from_relocInfo(char* displacement_address);

  // returns the first address after this primitive ic.
  char* end_addr();

  void print();
};

#endif

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