/*

 * Copyright (c) 1997, 2014, 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_VM_CODE_COMPILEDIC_HPP

#define SHARE_VM_CODE_COMPILEDIC_HPP

#include "code/nativeInst.hpp"

#include "interpreter/linkResolver.hpp"

#include "oops/compiledICHolder.hpp"

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

// 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]

//  (CompiledICHolder*)            (Klass*)     |

//          \                        /   \     /

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

//            \->-  Megamorphic -<-/

//                  (Method*)

//

// 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 Klass* 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 ICStub;

class CompiledICInfo : public StackObj {

 private:

  address _entry;              // entry point for call

  void*   _cached_value;         // Value of cached_value (either in stub or inline cache)

  bool    _is_icholder;          // Is the cached value a CompiledICHolder*

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

  bool    _to_interpreter;     // Call it to interpreter

  bool    _release_icholder;

 public:

  address entry() const        { return _entry; }

  Metadata*    cached_metadata() const         { assert(!_is_icholder, ""); return (Metadata*)_cached_value; }

  CompiledICHolder*    claim_cached_icholder() {

    assert(_is_icholder, "");

    assert(_cached_value != NULL, "must be non-NULL");

    _release_icholder = false;

    CompiledICHolder* icholder = (CompiledICHolder*)_cached_value;

    icholder->claim();

    return icholder;

  }

  bool    is_optimized() const { return _is_optimized; }

  bool         to_interpreter() const  { return _to_interpreter; }

  void set_compiled_entry(address entry, Klass* klass, bool is_optimized) {

    _entry      = entry;

    _cached_value = (void*)klass;

    _to_interpreter = false;

    _is_icholder = false;

    _is_optimized = is_optimized;

    _release_icholder = false;

  }

  void set_interpreter_entry(address entry, Method* method) {

    _entry      = entry;

    _cached_value = (void*)method;

    _to_interpreter = true;

    _is_icholder = false;

    _is_optimized = true;

    _release_icholder = false;

  }

  void set_icholder_entry(address entry, CompiledICHolder* icholder) {

    _entry      = entry;

    _cached_value = (void*)icholder;

    _to_interpreter = true;

    _is_icholder = true;

    _is_optimized = false;

    _release_icholder = true;

  }

  CompiledICInfo(): _entry(NULL), _cached_value(NULL), _is_icholder(false),

                    _to_interpreter(false), _is_optimized(false), _release_icholder(false) {

  }

  ~CompiledICInfo() {

    // In rare cases the info is computed but not used, so release any

    // CompiledICHolder* that was created

    if (_release_icholder) {

      assert(_is_icholder, "must be");

      CompiledICHolder* icholder = (CompiledICHolder*)_cached_value;

      icholder->claim();

      delete icholder;

    }

  }

};

class CompiledIC: public ResourceObj {

  friend class InlineCacheBuffer;

  friend class ICStub;

 private:

  NativeCall*   _ic_call;       // the call instruction

  NativeMovConstReg* _value;    // patchable value cell for this IC

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

  CompiledIC(nmethod* nm, NativeCall* ic_call);

  CompiledIC(RelocIterator* iter);

  void initialize_from_iter(RelocIterator* iter);

  static bool is_icholder_entry(address entry);

  // 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 internal_set_ic_destination(address entry_point, bool is_icstub, void* cache, bool is_icholder);

  void set_ic_destination(ICStub* stub);

  void set_ic_destination(address entry_point) {

    assert(_is_optimized, "use set_ic_destination_and_value instead");

    internal_set_ic_destination(entry_point, false, NULL, false);

  }

  // This only for use by ICStubs where the type of the value isn't known

  void set_ic_destination_and_value(address entry_point, void* value) {

    internal_set_ic_destination(entry_point, false, value, is_icholder_entry(entry_point));

  }

  void set_ic_destination_and_value(address entry_point, Metadata* value) {

    internal_set_ic_destination(entry_point, false, value, false);

  }

  void set_ic_destination_and_value(address entry_point, CompiledICHolder* value) {

    internal_set_ic_destination(entry_point, false, value, true);

  }

  // 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(nmethod* nm, address return_addr);

  friend CompiledIC* CompiledIC_at(nmethod* nm, address call_site);

  friend CompiledIC* CompiledIC_at(Relocation* call_site);

  friend CompiledIC* CompiledIC_at(RelocIterator* reloc_iter);

  // This is used to release CompiledICHolder*s from nmethods that

  // are about to be freed.  The callsite might contain other stale

  // values of other kinds so it must be careful.

  static void cleanup_call_site(virtual_call_Relocation* call_site);

  static bool is_icholder_call_site(virtual_call_Relocation* call_site);

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

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

  void* cached_value() const;

  CompiledICHolder* cached_icholder() const {

    assert(is_icholder_call(), "must be");

    return (CompiledICHolder*) cached_value();

  }

  Metadata* cached_metadata() const {

    assert(!is_icholder_call(), "must be");

    return (Metadata*) cached_value();

  }

  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;

  bool is_icholder_call() 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(CompiledICInfo& info);

  // Returns true if successful and false otherwise. The call can fail if memory

  // allocation in the code cache fails.

  bool 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(nmethod* nm, address return_addr) {

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

  c_ic->verify();

  return c_ic;

}

inline CompiledIC* CompiledIC_at(nmethod* nm, address call_site) {

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

  c_ic->verify();

  return c_ic;

}

inline CompiledIC* CompiledIC_at(Relocation* call_site) {

  assert(call_site->type() == relocInfo::virtual_call_type ||

         call_site->type() == relocInfo::opt_virtual_call_type, "wrong reloc. info");

  CompiledIC* c_ic = new CompiledIC(call_site->code(), nativeCall_at(call_site->addr()));

  c_ic->verify();

  return c_ic;

}

inline CompiledIC* CompiledIC_at(RelocIterator* reloc_iter) {

  assert(reloc_iter->type() == relocInfo::virtual_call_type ||

      reloc_iter->type() == relocInfo::opt_virtual_call_type, "wrong reloc. info");

  CompiledIC* c_ic = new CompiledIC(reloc_iter);

  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 Method* 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);

  // Code

  static void emit_to_interp_stub(CodeBuffer &cbuf);

  static int to_interp_stub_size();

  static int reloc_to_interp_stub();

  // 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());

}

#endif // SHARE_VM_CODE_COMPILEDIC_HPP