/*

 * 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.

 *

 *

 */

//-----------------------------------------------------------------------------

// The CompiledIC represents a compiled inline cache.

//

// In order to make patching of the inline cache MT-safe, we only allow the following

// transitions (when not at a safepoint):

//

//

//         [1] --<--  Clean -->---  [1]

//            /       (null)      \

//           /                     \      /-<-\

//          /          [2]          \    /     \

//      Interpreted  ---------> Monomorphic     | [3]

//  (compiledICHolderOop)        (klassOop)     |

//          \                        /   \     /

//       [4] \                      / [4] \->-/

//            \->-  Megamorphic -<-/

//                  (methodOop)

//

// The text in paranteses () refere to the value of the inline cache receiver (mov instruction)

//

// The numbers in square brackets refere to the kind of transition:

// [1]: Initial fixup. Receiver it found from debug information

// [2]: Compilation of a method

// [3]: Recompilation of a method (note: only entry is changed. The klassOop must stay the same)

// [4]: Inline cache miss. We go directly to megamorphic call.

//

// The class automatically inserts transition stubs (using the InlineCacheBuffer) when an MT-unsafe

// transition is made to a stub.

//

class CompiledIC;

class CompiledICInfo {

  friend class CompiledIC;

 private:

  address _entry;              // entry point for call

  Handle  _cached_oop;         // Value of cached_oop (either in stub or inline cache)

  bool    _is_optimized;       // it is an optimized virtual call (i.e., can be statically bound)

  bool    _to_interpreter;     // Call it to interpreter

 public:

  address entry() const        { return _entry; }

  Handle  cached_oop() const   { return _cached_oop; }

  bool    is_optimized() const { return _is_optimized; }

};

class CompiledIC: public ResourceObj {

  friend class InlineCacheBuffer;

  friend class ICStub;

 private:

  NativeCall*   _ic_call;       // the call instruction

  oop*          _oop_addr;      // patchable oop cell for this IC

  RelocIterator _oops;          // iteration over any and all set-oop instructions

  bool          _is_optimized;  // an optimized virtual call (i.e., no compiled IC)

  CompiledIC(NativeCall* ic_call);

  CompiledIC(Relocation* ic_reloc);    // Must be of virtual_call_type/opt_virtual_call_type

  // low-level inline-cache manipulation. Cannot be accessed directly, since it might not be MT-safe

  // to change an inline-cache. These changes the underlying inline-cache directly. They *newer* make

  // changes to a transition stub.

  void set_ic_destination(address entry_point);

  void set_cached_oop(oop cache);

  // Reads the location of the transition stub. This will fail with an assertion, if no transition stub is

  // associated with the inline cache.

  address stub_address() const;

  bool is_in_transition_state() const;  // Use InlineCacheBuffer

 public:

  // conversion (machine PC to CompiledIC*)

  friend CompiledIC* CompiledIC_before(address return_addr);

  friend CompiledIC* CompiledIC_at(address call_site);

  friend CompiledIC* CompiledIC_at(Relocation* call_site);

  // Return the cached_oop/destination associated with this inline cache. If the cache currently points

  // to a transition stub, it will read the values from the transition stub.

  oop  cached_oop() const;

  address ic_destination() const;

  bool is_optimized() const   { return _is_optimized; }

  // State

  bool is_clean() const;

  bool is_megamorphic() const;

  bool is_call_to_compiled() const;

  bool is_call_to_interpreted() const;

  address end_of_call() { return  _ic_call->return_address(); }

  // MT-safe patching of inline caches. Note: Only safe to call is_xxx when holding the CompiledIC_ock

  // so you are guaranteed that no patching takes place. The same goes for verify.

  //

  // Note: We do not provide any direct access to the stub code, to prevent parts of the code

  // to manipulate the inline cache in MT-unsafe ways.

  //

  // They all takes a TRAP argument, since they can cause a GC if the inline-cache buffer is full.

  //

  void set_to_clean();  // Can only be called during a safepoint operation

  void set_to_monomorphic(const CompiledICInfo& info);

  void set_to_megamorphic(CallInfo* call_info, Bytecodes::Code bytecode, TRAPS);

  static void compute_monomorphic_entry(methodHandle method, KlassHandle receiver_klass,

                                        bool is_optimized, bool static_bound, CompiledICInfo& info, TRAPS);

  // Location

  address instruction_address() const { return _ic_call->instruction_address(); }

  // Misc

  void print()             PRODUCT_RETURN;

  void print_compiled_ic() PRODUCT_RETURN;

  void verify()            PRODUCT_RETURN;

};

inline CompiledIC* CompiledIC_before(address return_addr) {

  CompiledIC* c_ic = new CompiledIC(nativeCall_before(return_addr));

  c_ic->verify();

  return c_ic;

}

inline CompiledIC* CompiledIC_at(address call_site) {

  CompiledIC* c_ic = new CompiledIC(nativeCall_at(call_site));

  c_ic->verify();

  return c_ic;

}

inline CompiledIC* CompiledIC_at(Relocation* call_site) {

  CompiledIC* c_ic = new CompiledIC(call_site);

  c_ic->verify();

  return c_ic;

}

//-----------------------------------------------------------------------------

// The CompiledStaticCall represents a call to a static method in the compiled

//

// Transition diagram of a static call site is somewhat simpler than for an inlined cache:

//

//

//           -----<----- Clean ----->-----

//          /                             \

//         /                               \

//    compilled code <------------> interpreted code

//

//  Clean:            Calls directly to runtime method for fixup

//  Compiled code:    Calls directly to compiled code

//  Interpreted code: Calls to stub that set methodOop reference

//

//

class CompiledStaticCall;

class StaticCallInfo {

 private:

  address      _entry;          // Entrypoint

  methodHandle _callee;         // Callee (used when calling interpreter)

  bool         _to_interpreter; // call to interpreted method (otherwise compiled)

  friend class CompiledStaticCall;

 public:

  address      entry() const    { return _entry;  }

  methodHandle callee() const   { return _callee; }

};

class CompiledStaticCall: public NativeCall {

  friend class CompiledIC;

  // Also used by CompiledIC

  void set_to_interpreted(methodHandle callee, address entry);

  bool is_optimized_virtual();

 public:

  friend CompiledStaticCall* compiledStaticCall_before(address return_addr);

  friend CompiledStaticCall* compiledStaticCall_at(address native_call);

  friend CompiledStaticCall* compiledStaticCall_at(Relocation* call_site);

  // State

  bool is_clean() const;

  bool is_call_to_compiled() const;

  bool is_call_to_interpreted() const;

  // Clean static call (will force resolving on next use)

  void set_to_clean();

  // Set state. The entry must be the same, as computed by compute_entry.

  // Computation and setting is split up, since the actions are separate during

  // a OptoRuntime::resolve_xxx.

  void set(const StaticCallInfo& info);

  // Compute entry point given a method

  static void compute_entry(methodHandle m, StaticCallInfo& info);

  // Stub support

  address find_stub();

  static void set_stub_to_clean(static_stub_Relocation* static_stub);

  // Misc.

  void print()  PRODUCT_RETURN;

  void verify() PRODUCT_RETURN;

};

inline CompiledStaticCall* compiledStaticCall_before(address return_addr) {

  CompiledStaticCall* st = (CompiledStaticCall*)nativeCall_before(return_addr);

  st->verify();

  return st;

}

inline CompiledStaticCall* compiledStaticCall_at(address native_call) {

  CompiledStaticCall* st = (CompiledStaticCall*)native_call;

  st->verify();

  return st;

}

inline CompiledStaticCall* compiledStaticCall_at(Relocation* call_site) {

  return compiledStaticCall_at(call_site->addr());

}