/*

 * Copyright (c) 1997, 2019, 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

 * 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.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 *

 */

#ifndef SHARE_CODE_ICBUFFER_HPP

#define SHARE_CODE_ICBUFFER_HPP

#include "asm/codeBuffer.hpp"

#include "code/stubs.hpp"

#include "interpreter/bytecodes.hpp"

#include "memory/allocation.hpp"

#include "runtime/safepointVerifiers.hpp"

#include "utilities/align.hpp"

#include "utilities/debug.hpp"

#include "utilities/macros.hpp"

//

// For CompiledIC's:

//

// In cases where we do not have MT-safe state transformation,

// we go to a transition state, using ICStubs. At a safepoint,

// the inline caches are transferred from the transitional code:

//

//    instruction_address --> 01 set xxx_oop, Ginline_cache_klass

//                            23 jump_to Gtemp, yyyy

//                            4  nop

class ICStub: public Stub {

 private:

  int                 _size;       // total size of the stub incl. code

  address             _ic_site;    // points at call instruction of owning ic-buffer

  /* stub code follows here */

 protected:

  friend class ICStubInterface;

  // This will be called only by ICStubInterface

  void    initialize(int size,

                     CodeStrings strings)        { _size = size; _ic_site = NULL; }

  void    finalize(); // called when a method is removed

  // General info

  int     size() const                           { return _size; }

  static  int code_size_to_size(int code_size)   { return align_up((int)sizeof(ICStub), CodeEntryAlignment) + code_size; }

 public:

  // Creation

  void set_stub(CompiledIC *ic, void* cached_value, address dest_addr);

  // Code info

  address code_begin() const                     { return (address)this + align_up(sizeof(ICStub), CodeEntryAlignment); }

  address code_end() const                       { return (address)this + size(); }

  // Call site info

  address ic_site() const                        { return _ic_site; }

  void    clear();

  bool    is_empty() const                       { return _ic_site == NULL; }

  // stub info

  address destination() const;  // destination of jump instruction

  void* cached_value() const;   // cached_value for stub

  // Debugging

  void    verify()            PRODUCT_RETURN;

  void    print()             PRODUCT_RETURN;

  // Creation

  friend ICStub* ICStub_from_destination_address(address destination_address);

};

// ICStub Creation

inline ICStub* ICStub_from_destination_address(address destination_address) {

  ICStub* stub = (ICStub*) (destination_address - align_up(sizeof(ICStub), CodeEntryAlignment));

  #ifdef ASSERT

  stub->verify();

  #endif

  return stub;

}

#ifdef ASSERT

// The ICRefillVerifier class is a stack allocated RAII object used to

// detect if a failed IC transition that required IC stub refilling has

// been accidentally missed. It is up to the caller to in that case

// refill IC stubs.

class ICRefillVerifier: StackObj {

  bool _refill_requested;

  bool _refill_remembered;

 public:

  ICRefillVerifier();

  ~ICRefillVerifier();

  void request_refill() { _refill_requested = true; }

  void request_remembered() { _refill_remembered = true; }

};

// The ICRefillVerifierMark is used to set the thread's current

// ICRefillVerifier to a provided one. This is useful in particular

// when transitioning IC stubs in parallel and refilling from the

// master thread invoking the IC stub transitioning code.

class ICRefillVerifierMark: StackObj {

 public:

  ICRefillVerifierMark(ICRefillVerifier* verifier);

  ~ICRefillVerifierMark();

};

#else

class ICRefillVerifier: StackObj {

 public:

  ICRefillVerifier() {}

};

class ICRefillVerifierMark: StackObj {

 public:

  ICRefillVerifierMark(ICRefillVerifier* verifier) {}

};

#endif

class InlineCacheBuffer: public AllStatic {

 private:

  // friends

  friend class ICStub;

  static int ic_stub_code_size();

  static StubQueue* _buffer;

  static CompiledICHolder* _pending_released;

  static int _pending_count;

  static StubQueue* buffer()                         { return _buffer;         }

  static ICStub* new_ic_stub();

  // Machine-dependent implementation of ICBuffer

  static void    assemble_ic_buffer_code(address code_begin, void* cached_value, address entry_point);

  static address ic_buffer_entry_point  (address code_begin);

  static void*   ic_buffer_cached_value (address code_begin);

 public:

    // Initialization; must be called before first usage

  static void initialize();

  // Access

  static bool contains(address instruction_address);

    // removes the ICStubs after backpatching

  static void update_inline_caches();

  static void refill_ic_stubs();

  // for debugging

  static bool is_empty();

  static void release_pending_icholders();

  static void queue_for_release(CompiledICHolder* icholder);

  static int pending_icholder_count() { return _pending_count; }

  // New interface

  static bool    create_transition_stub(CompiledIC *ic, void* cached_value, address entry);

  static address ic_destination_for(CompiledIC *ic);

  static void*   cached_value_for(CompiledIC *ic);

};

#endif // SHARE_CODE_ICBUFFER_HPP