/*

 * Copyright (c) 1997, 2010, 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.

 *

 */

// This file contains the platform-independent parts

// of the interpreter and the interpreter generator.

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

// An InterpreterCodelet is a piece of interpreter code. All

// interpreter code is generated into little codelets which

// contain extra information for debugging and printing purposes.

class InterpreterCodelet: public Stub {

  friend class VMStructs;

 private:

  int         _size;                             // the size in bytes

  const char* _description;                      // a description of the codelet, for debugging & printing

  Bytecodes::Code _bytecode;                     // associated bytecode if any

 public:

  // Initialization/finalization

  void    initialize(int size)                   { _size = size; }

  void    finalize()                             { ShouldNotCallThis(); }

  // General info/converters

  int     size() const                           { return _size; }

  static  int code_size_to_size(int code_size)   { return round_to(sizeof(InterpreterCodelet), CodeEntryAlignment) + code_size; }

  // Code info

  address code_begin() const                     { return (address)this + round_to(sizeof(InterpreterCodelet), CodeEntryAlignment); }

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

  // Debugging

  void    verify();

  void    print_on(outputStream* st) const;

  void    print() const { print_on(tty); }

  // Interpreter-specific initialization

  void    initialize(const char* description, Bytecodes::Code bytecode);

  // Interpreter-specific attributes

  int         code_size() const                  { return code_end() - code_begin(); }

  const char* description() const                { return _description; }

  Bytecodes::Code bytecode() const               { return _bytecode; }

};

// Define a prototype interface

DEF_STUB_INTERFACE(InterpreterCodelet);

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

// A CodeletMark serves as an automatic creator/initializer for Codelets

// (As a subclass of ResourceMark it automatically GC's the allocated

// code buffer and assemblers).

class CodeletMark: ResourceMark {

 private:

  InterpreterCodelet*         _clet;

  InterpreterMacroAssembler** _masm;

  CodeBuffer                  _cb;

  int codelet_size() {

    // Request the whole code buffer (minus a little for alignment).

    // The commit call below trims it back for each codelet.

    int codelet_size = AbstractInterpreter::code()->available_space() - 2*K;

    // Guarantee there's a little bit of code space left.

    guarantee (codelet_size > 0 && (size_t)codelet_size >  2*K,

               "not enough space for interpreter generation");

    return codelet_size;

  }

 public:

  CodeletMark(

    InterpreterMacroAssembler*& masm,

    const char* description,

    Bytecodes::Code bytecode = Bytecodes::_illegal):

    _clet((InterpreterCodelet*)AbstractInterpreter::code()->request(codelet_size())),

    _cb(_clet->code_begin(), _clet->code_size())

  { // request all space (add some slack for Codelet data)

    assert (_clet != NULL, "we checked not enough space already");

    // initialize Codelet attributes

    _clet->initialize(description, bytecode);

    // create assembler for code generation

    masm  = new InterpreterMacroAssembler(&_cb);

    _masm = &masm;

  }

  ~CodeletMark() {

    // align so printing shows nop's instead of random code at the end (Codelets are aligned)

    (*_masm)->align(wordSize);

    // make sure all code is in code buffer

    (*_masm)->flush();

    // commit Codelet

    AbstractInterpreter::code()->commit((*_masm)->code()->pure_insts_size());

    // make sure nobody can use _masm outside a CodeletMark lifespan

    *_masm = NULL;

  }

};

// Wrapper classes to produce Interpreter/InterpreterGenerator from either

// the c++ interpreter or the template interpreter.

class Interpreter: public CC_INTERP_ONLY(CppInterpreter) NOT_CC_INTERP(TemplateInterpreter) {

  public:

  // Debugging/printing

  static InterpreterCodelet* codelet_containing(address pc)     { return (InterpreterCodelet*)_code->stub_containing(pc); }

};