/*

 * Copyright (c) 1997, 2017, 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_RUNTIME_JAVACALLS_HPP

#define SHARE_VM_RUNTIME_JAVACALLS_HPP

#include "memory/allocation.hpp"

#include "oops/method.hpp"

#include "runtime/handles.hpp"

#include "runtime/javaFrameAnchor.hpp"

#include "runtime/thread.hpp"

#include "runtime/vmThread.hpp"

#include "utilities/macros.hpp"

#include CPU_HEADER(jniTypes)

// A JavaCallWrapper is constructed before each JavaCall and destructed after the call.

// Its purpose is to allocate/deallocate a new handle block and to save/restore the last

// Java fp/sp. A pointer to the JavaCallWrapper is stored on the stack.

class JavaCallWrapper: StackObj {

  friend class VMStructs;

 private:

  JavaThread*      _thread;                 // the thread to which this call belongs

  JNIHandleBlock*  _handles;                // the saved handle block

  Method*          _callee_method;          // to be able to collect arguments if entry frame is top frame

  oop              _receiver;               // the receiver of the call (if a non-static call)

  JavaFrameAnchor  _anchor;                 // last thread anchor state that we must restore

  JavaValue*       _result;                 // result value

 public:

  // Construction/destruction

   JavaCallWrapper(const methodHandle& callee_method, Handle receiver, JavaValue* result, TRAPS);

  ~JavaCallWrapper();

  // Accessors

  JavaThread*      thread() const           { return _thread; }

  JNIHandleBlock*  handles() const          { return _handles; }

  JavaFrameAnchor* anchor(void)             { return &_anchor; }

  JavaValue*       result() const           { return _result; }

  // GC support

  Method*          callee_method()          { return _callee_method; }

  oop              receiver()               { return _receiver; }

  void             oops_do(OopClosure* f);

  bool             is_first_frame() const   { return _anchor.last_Java_sp() == NULL; }

};

// Encapsulates arguments to a JavaCall (faster, safer, and more convenient than using var-args)

class JavaCallArguments : public StackObj {

 private:

  enum Constants {

   _default_size = 8    // Must be at least # of arguments in JavaCalls methods

  };

  intptr_t    _value_buffer      [_default_size + 1];

  u_char      _value_state_buffer[_default_size + 1];

  intptr_t*   _value;

  u_char*     _value_state;

  int         _size;

  int         _max_size;

  bool        _start_at_zero;      // Support late setting of receiver

  JVMCI_ONLY(nmethod*    _alternative_target;) // Nmethod that should be called instead of normal target

  void initialize() {

    // Starts at first element to support set_receiver.

    _value       = &_value_buffer[1];

    _value_state = &_value_state_buffer[1];

    _max_size = _default_size;

    _size = 0;

    _start_at_zero = false;

    JVMCI_ONLY(_alternative_target = NULL;)

  }

  // Helper for push_oop and the like.  The value argument is a

  // "handle" that refers to an oop.  We record the address of the

  // handle rather than the designated oop.  The handle is later

  // resolved to the oop by parameters().  This delays the exposure of

  // naked oops until it is GC-safe.

  template<typename T>

  inline int push_oop_impl(T handle, int size) {

    // JNITypes::put_obj expects an oop value, so we play fast and

    // loose with the type system.  The cast from handle type to oop

    // *must* use a C-style cast.  In a product build it performs a

    // reinterpret_cast. In a debug build (more accurately, in a

    // CHECK_UNHANDLED_OOPS build) it performs a static_cast, invoking

    // the debug-only oop class's conversion from void* constructor.

    JNITypes::put_obj((oop)handle, _value, size); // Updates size.

    return size;                // Return the updated size.

  }

 public:

  JavaCallArguments() { initialize(); }

  JavaCallArguments(Handle receiver) {

    initialize();

    push_oop(receiver);

  }

  JavaCallArguments(int max_size) {

    if (max_size > _default_size) {

      _value = NEW_RESOURCE_ARRAY(intptr_t, max_size + 1);

      _value_state = NEW_RESOURCE_ARRAY(u_char, max_size + 1);

      // Reserve room for potential receiver in value and state

      _value++;

      _value_state++;

      _max_size = max_size;

      _size = 0;

      _start_at_zero = false;

      JVMCI_ONLY(_alternative_target = NULL;)

    } else {

      initialize();

    }

  }

#if INCLUDE_JVMCI

  void set_alternative_target(nmethod* target) {

    _alternative_target = target;

  }

  nmethod* alternative_target() {

    return _alternative_target;

  }

#endif

  // The possible values for _value_state elements.

  enum {

    value_state_primitive,

    value_state_oop,

    value_state_handle,

    value_state_jobject,

    value_state_limit

  };

  inline void push_oop(Handle h) {

    _value_state[_size] = value_state_handle;

    _size = push_oop_impl(h.raw_value(), _size);

  }

  inline void push_jobject(jobject h) {

    _value_state[_size] = value_state_jobject;

    _size = push_oop_impl(h, _size);

  }

  inline void push_int(int i) {

    _value_state[_size] = value_state_primitive;

    JNITypes::put_int(i, _value, _size);

  }

  inline void push_double(double d) {

    _value_state[_size] = value_state_primitive;

    _value_state[_size + 1] = value_state_primitive;

    JNITypes::put_double(d, _value, _size);

  }

  inline void push_long(jlong l) {

    _value_state[_size] = value_state_primitive;

    _value_state[_size + 1] = value_state_primitive;

    JNITypes::put_long(l, _value, _size);

  }

  inline void push_float(float f) {

    _value_state[_size] = value_state_primitive;

    JNITypes::put_float(f, _value, _size);

  }

  // receiver

  Handle receiver() {

    assert(_size > 0, "must at least be one argument");

    assert(_value_state[0] == value_state_handle,

           "first argument must be an oop");

    assert(_value[0] != 0, "receiver must be not-null");

    return Handle((oop*)_value[0], false);

  }

  void set_receiver(Handle h) {

    assert(_start_at_zero == false, "can only be called once");

    _start_at_zero = true;

    _value_state--;

    _value--;

    _size++;

    _value_state[0] = value_state_handle;

    push_oop_impl(h.raw_value(), 0);

  }

  // Converts all Handles to oops, and returns a reference to parameter vector

  intptr_t* parameters() ;

  int   size_of_parameters() const { return _size; }

  // Verify that pushed arguments fits a given method

  void verify(const methodHandle& method, BasicType return_type);

};

// All calls to Java have to go via JavaCalls. Sets up the stack frame

// and makes sure that the last_Java_frame pointers are chained correctly.

//

class JavaCalls: AllStatic {

  static void call_helper(JavaValue* result, const methodHandle& method, JavaCallArguments* args, TRAPS);

 public:

  // call_special

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

  // The receiver must be first oop in argument list

  static void call_special(JavaValue* result, Klass* klass, Symbol* name, Symbol* signature, JavaCallArguments* args, TRAPS);

  static void call_special(JavaValue* result, Handle receiver, Klass* klass, Symbol* name, Symbol* signature, TRAPS); // No args

  static void call_special(JavaValue* result, Handle receiver, Klass* klass, Symbol* name, Symbol* signature, Handle arg1, TRAPS);

  static void call_special(JavaValue* result, Handle receiver, Klass* klass, Symbol* name, Symbol* signature, Handle arg1, Handle arg2, TRAPS);

  // virtual call

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

  // The receiver must be first oop in argument list

  static void call_virtual(JavaValue* result, Klass* spec_klass, Symbol* name, Symbol* signature, JavaCallArguments* args, TRAPS);

  static void call_virtual(JavaValue* result, Handle receiver, Klass* spec_klass, Symbol* name, Symbol* signature, TRAPS); // No args

  static void call_virtual(JavaValue* result, Handle receiver, Klass* spec_klass, Symbol* name, Symbol* signature, Handle arg1, TRAPS);

  static void call_virtual(JavaValue* result, Handle receiver, Klass* spec_klass, Symbol* name, Symbol* signature, Handle arg1, Handle arg2, TRAPS);

  // Static call

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

  static void call_static(JavaValue* result, Klass* klass, Symbol* name, Symbol* signature, JavaCallArguments* args, TRAPS);

  static void call_static(JavaValue* result, Klass* klass, Symbol* name, Symbol* signature, TRAPS);

  static void call_static(JavaValue* result, Klass* klass, Symbol* name, Symbol* signature, Handle arg1, TRAPS);

  static void call_static(JavaValue* result, Klass* klass, Symbol* name, Symbol* signature, Handle arg1, Handle arg2, TRAPS);

  static void call_static(JavaValue* result, Klass* klass, Symbol* name, Symbol* signature, Handle arg1, Handle arg2, Handle arg3, TRAPS);

  // Low-level interface

  static void call(JavaValue* result, const methodHandle& method, JavaCallArguments* args, TRAPS);

};

#endif // SHARE_VM_RUNTIME_JAVACALLS_HPP