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 /*

  * 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.

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  */

 #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