/*

 * Copyright (c) 2003, 2011, 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.

 *

 */

#include "precompiled.hpp"

#include "classfile/stackMapFrame.hpp"

#include "classfile/verifier.hpp"

#include "memory/resourceArea.hpp"

#include "oops/oop.inline.hpp"

#include "oops/symbol.hpp"

#include "runtime/handles.inline.hpp"

#include "utilities/globalDefinitions.hpp"

StackMapFrame::StackMapFrame(u2 max_locals, u2 max_stack, ClassVerifier* v) :

                      _offset(0), _locals_size(0), _stack_size(0), _flags(0),

                      _max_locals(max_locals), _max_stack(max_stack),

                      _verifier(v) {

  Thread* thr = v->thread();

  _locals = NEW_RESOURCE_ARRAY_IN_THREAD(thr, VerificationType, max_locals);

  _stack = NEW_RESOURCE_ARRAY_IN_THREAD(thr, VerificationType, max_stack);

  int32_t i;

  for(i = 0; i < max_locals; i++) {

    _locals[i] = VerificationType::bogus_type();

  }

  for(i = 0; i < max_stack; i++) {

    _stack[i] = VerificationType::bogus_type();

  }

}

StackMapFrame* StackMapFrame::frame_in_exception_handler(u1 flags) {

  Thread* thr = _verifier->thread();

  VerificationType* stack = NEW_RESOURCE_ARRAY_IN_THREAD(thr, VerificationType, 1);

  StackMapFrame* frame = new StackMapFrame(_offset, flags, _locals_size, 0, _max_locals, _max_stack, _locals, stack, _verifier);

  return frame;

}

bool StackMapFrame::has_new_object() const {

  int32_t i;

  for (i = 0; i < _max_locals; i++) {

    if (_locals[i].is_uninitialized()) {

      return true;

    }

  }

  for (i = 0; i < _stack_size; i++) {

    if (_stack[i].is_uninitialized()) {

      return true;

    }

  }

  return false;

}

void StackMapFrame::initialize_object(

    VerificationType old_object, VerificationType new_object) {

  int32_t i;

  for (i = 0; i < _max_locals; i++) {

    if (_locals[i].equals(old_object)) {

      _locals[i] = new_object;

    }

  }

  for (i = 0; i < _stack_size; i++) {

    if (_stack[i].equals(old_object)) {

      _stack[i] = new_object;

    }

  }

  if (old_object == VerificationType::uninitialized_this_type()) {

    // "this" has been initialized - reset flags

    _flags = 0;

  }

}

VerificationType StackMapFrame::set_locals_from_arg(

    const methodHandle m, VerificationType thisKlass, TRAPS) {

  SignatureStream ss(m->signature());

  int init_local_num = 0;

  if (!m->is_static()) {

    init_local_num++;

    // add one extra argument for instance method

    if (m->name() == vmSymbols::object_initializer_name() &&

       thisKlass.name() != vmSymbols::java_lang_Object()) {

      _locals[0] = VerificationType::uninitialized_this_type();

      _flags |= FLAG_THIS_UNINIT;

    } else {

      _locals[0] = thisKlass;

    }

  }

  // local num may be greater than size of parameters because long/double occupies two slots

  while(!ss.at_return_type()) {

    init_local_num += _verifier->change_sig_to_verificationType(

      &ss, &_locals[init_local_num],

      CHECK_VERIFY_(verifier(), VerificationType::bogus_type()));

    ss.next();

  }

  _locals_size = init_local_num;

  switch (ss.type()) {

    case T_OBJECT:

    case T_ARRAY:

    {

      Symbol* sig = ss.as_symbol(CHECK_(VerificationType::bogus_type()));

      // Create another symbol to save as signature stream unreferences

      // this symbol.

      Symbol* sig_copy =

        verifier()->create_temporary_symbol(sig, 0, sig->utf8_length(),

                                 CHECK_(VerificationType::bogus_type()));

      assert(sig_copy == sig, "symbols don't match");

      return VerificationType::reference_type(sig_copy);

    }

    case T_INT:     return VerificationType::integer_type();

    case T_BYTE:    return VerificationType::byte_type();

    case T_CHAR:    return VerificationType::char_type();

    case T_SHORT:   return VerificationType::short_type();

    case T_BOOLEAN: return VerificationType::boolean_type();

    case T_FLOAT:   return VerificationType::float_type();

    case T_DOUBLE:  return VerificationType::double_type();

    case T_LONG:    return VerificationType::long_type();

    case T_VOID:    return VerificationType::bogus_type();

    default:

      ShouldNotReachHere();

  }

  return VerificationType::bogus_type();

}

void StackMapFrame::copy_locals(const StackMapFrame* src) {

  int32_t len = src->locals_size() < _locals_size ?

    src->locals_size() : _locals_size;

  for (int32_t i = 0; i < len; i++) {

    _locals[i] = src->locals()[i];

  }

}

void StackMapFrame::copy_stack(const StackMapFrame* src) {

  int32_t len = src->stack_size() < _stack_size ?

    src->stack_size() : _stack_size;

  for (int32_t i = 0; i < len; i++) {

    _stack[i] = src->stack()[i];

  }

}

bool StackMapFrame::is_assignable_to(

    VerificationType* from, VerificationType* to, int32_t len, TRAPS) const {

  for (int32_t i = 0; i < len; i++) {

    bool subtype = to[i].is_assignable_from(

      from[i], verifier(), THREAD);

    if (!subtype) {

      return false;

    }

  }

  return true;

}

bool StackMapFrame::has_flag_match_exception(

    const StackMapFrame* target) const {

  // We allow flags of {UninitThis} to assign to {} if-and-only-if the

  // target frame does not depend upon the current type.

  // This is slightly too strict, as we need only enforce that the

  // slots that were initialized by the <init> (the things that were

  // UninitializedThis before initialize_object() converted them) are unused.

  // However we didn't save that information so we'll enforce this upon

  // anything that might have been initialized.  This is a rare situation

  // and javac never generates code that would end up here, but some profilers

  // (such as NetBeans) might, when adding exception handlers in <init>

  // methods to cover the invokespecial instruction.  See 7020118.

  assert(max_locals() == target->max_locals() &&

         stack_size() == target->stack_size(), "StackMap sizes must match");

  VerificationType top = VerificationType::top_type();

  VerificationType this_type = verifier()->current_type();

  if (!flag_this_uninit() || target->flags() != 0) {

    return false;

  }

  for (int i = 0; i < target->locals_size(); ++i) {

    if (locals()[i] == this_type && target->locals()[i] != top) {

      return false;

    }

  }

  for (int i = 0; i < target->stack_size(); ++i) {

    if (stack()[i] == this_type && target->stack()[i] != top) {

      return false;

    }

  }

  return true;

}

bool StackMapFrame::is_assignable_to(

    const StackMapFrame* target, bool is_exception_handler, TRAPS) const {

  if (_max_locals != target->max_locals() ||

      _stack_size != target->stack_size()) {

    return false;

  }

  // Only need to compare type elements up to target->locals() or target->stack().

  // The remaining type elements in this state can be ignored because they are

  // assignable to bogus type.

  bool match_locals = is_assignable_to(

    _locals, target->locals(), target->locals_size(), CHECK_false);

  bool match_stack = is_assignable_to(

    _stack, target->stack(), _stack_size, CHECK_false);

  bool match_flags = (_flags | target->flags()) == target->flags();

  return match_locals && match_stack &&

    (match_flags || (is_exception_handler && has_flag_match_exception(target)));

}

VerificationType StackMapFrame::pop_stack_ex(VerificationType type, TRAPS) {

  if (_stack_size <= 0) {

    verifier()->verify_error(_offset, "Operand stack underflow");

    return VerificationType::bogus_type();

  }

  VerificationType top = _stack[--_stack_size];

  bool subtype = type.is_assignable_from(

    top, verifier(), CHECK_(VerificationType::bogus_type()));

  if (!subtype) {

    verifier()->verify_error(_offset, "Bad type on operand stack");

    return VerificationType::bogus_type();

  }

  NOT_PRODUCT( _stack[_stack_size] = VerificationType::bogus_type(); )

  return top;

}

VerificationType StackMapFrame::get_local(

    int32_t index, VerificationType type, TRAPS) {

  if (index >= _max_locals) {

    verifier()->verify_error(_offset, "Local variable table overflow");

    return VerificationType::bogus_type();

  }

  bool subtype = type.is_assignable_from(_locals[index],

    verifier(), CHECK_(VerificationType::bogus_type()));

  if (!subtype) {

    verifier()->verify_error(_offset, "Bad local variable type");

    return VerificationType::bogus_type();

  }

  if(index >= _locals_size) { _locals_size = index + 1; }

  return _locals[index];

}

void StackMapFrame::get_local_2(

    int32_t index, VerificationType type1, VerificationType type2, TRAPS) {

  assert(type1.is_long() || type1.is_double(), "must be long/double");

  assert(type2.is_long2() || type2.is_double2(), "must be long/double_2");

  if (index >= _locals_size - 1) {

    verifier()->verify_error(_offset, "get long/double overflows locals");

    return;

  }

  bool subtype1 = type1.is_assignable_from(

    _locals[index], verifier(), CHECK);

  bool subtype2 = type2.is_assignable_from(

    _locals[index+1], verifier(), CHECK);

  if (!subtype1 || !subtype2) {

    verifier()->verify_error(_offset, "Bad local variable type");

    return;

  }

}

void StackMapFrame::set_local(int32_t index, VerificationType type, TRAPS) {

  assert(!type.is_check(), "Must be a real type");

  if (index >= _max_locals) {

    verifier()->verify_error("Local variable table overflow", _offset);

    return;

  }

  // If type at index is double or long, set the next location to be unusable

  if (_locals[index].is_double() || _locals[index].is_long()) {

    assert((index + 1) < _locals_size, "Local variable table overflow");

    _locals[index + 1] = VerificationType::bogus_type();

  }

  // If type at index is double_2 or long_2, set the previous location to be unusable

  if (_locals[index].is_double2() || _locals[index].is_long2()) {

    assert(index >= 1, "Local variable table underflow");

    _locals[index - 1] = VerificationType::bogus_type();

  }

  _locals[index] = type;

  if (index >= _locals_size) {

#ifdef ASSERT

    for (int i=_locals_size; i<index; i++) {

      assert(_locals[i] == VerificationType::bogus_type(),

             "holes must be bogus type");

    }

#endif

    _locals_size = index + 1;

  }

}

void StackMapFrame::set_local_2(

    int32_t index, VerificationType type1, VerificationType type2, TRAPS) {

  assert(type1.is_long() || type1.is_double(), "must be long/double");

  assert(type2.is_long2() || type2.is_double2(), "must be long/double_2");

  if (index >= _max_locals - 1) {

    verifier()->verify_error("Local variable table overflow", _offset);

    return;

  }

  // If type at index+1 is double or long, set the next location to be unusable

  if (_locals[index+1].is_double() || _locals[index+1].is_long()) {

    assert((index + 2) < _locals_size, "Local variable table overflow");

    _locals[index + 2] = VerificationType::bogus_type();

  }

  // If type at index is double_2 or long_2, set the previous location to be unusable

  if (_locals[index].is_double2() || _locals[index].is_long2()) {

    assert(index >= 1, "Local variable table underflow");

    _locals[index - 1] = VerificationType::bogus_type();

  }

  _locals[index] = type1;

  _locals[index+1] = type2;

  if (index >= _locals_size - 1) {

#ifdef ASSERT

    for (int i=_locals_size; i<index; i++) {

      assert(_locals[i] == VerificationType::bogus_type(),

             "holes must be bogus type");

    }

#endif

    _locals_size = index + 2;

  }

}

#ifndef PRODUCT

void StackMapFrame::print() const {

  tty->print_cr("stackmap_frame[%d]:", _offset);

  tty->print_cr("flags = 0x%x", _flags);

  tty->print("locals[%d] = { ", _locals_size);

  for (int32_t i = 0; i < _locals_size; i++) {

    _locals[i].print_on(tty);

  }

  tty->print_cr(" }");

  tty->print("stack[%d] = { ", _stack_size);

  for (int32_t j = 0; j < _stack_size; j++) {

    _stack[j].print_on(tty);

  }

  tty->print_cr(" }");

}

#endif