/*

 * Copyright (c) 1998, 2012, 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 "gc_implementation/shared/markSweep.inline.hpp"

#include "interpreter/interpreter.hpp"

#include "interpreter/rewriter.hpp"

#include "memory/universe.inline.hpp"

#include "oops/cpCacheOop.hpp"

#include "oops/objArrayOop.hpp"

#include "oops/oop.inline.hpp"

#include "prims/jvmtiRedefineClassesTrace.hpp"

#include "runtime/handles.inline.hpp"

// Implememtation of ConstantPoolCacheEntry

void ConstantPoolCacheEntry::initialize_entry(int index) {

  assert(0 < index && index < 0x10000, "sanity check");

  _indices = index;

  assert(constant_pool_index() == index, "");

}

void ConstantPoolCacheEntry::initialize_secondary_entry(int main_index) {

  assert(0 <= main_index && main_index < 0x10000, "sanity check");

  _indices = (main_index << 16);

  assert(main_entry_index() == main_index, "");

}

int ConstantPoolCacheEntry::as_flags(TosState state, bool is_final,

                    bool is_vfinal, bool is_volatile,

                    bool is_method_interface, bool is_method) {

  int f = state;

  assert( state < number_of_states, "Invalid state in as_flags");

  f <<= 1;

  if (is_final) f |= 1;

  f <<= 1;

  if (is_vfinal) f |= 1;

  f <<= 1;

  if (is_volatile) f |= 1;

  f <<= 1;

  if (is_method_interface) f |= 1;

  f <<= 1;

  if (is_method) f |= 1;

  f <<= ConstantPoolCacheEntry::hotSwapBit;

  // Preserve existing flag bit values

#ifdef ASSERT

  int old_state = ((_flags >> tosBits) & 0x0F);

  assert(old_state == 0 || old_state == state,

         "inconsistent cpCache flags state");

#endif

  return (_flags | f) ;

}

void ConstantPoolCacheEntry::set_bytecode_1(Bytecodes::Code code) {

#ifdef ASSERT

  // Read once.

  volatile Bytecodes::Code c = bytecode_1();

  assert(c == 0 || c == code || code == 0, "update must be consistent");

#endif

  // Need to flush pending stores here before bytecode is written.

  OrderAccess::release_store_ptr(&_indices, _indices | ((u_char)code << 16));

}

void ConstantPoolCacheEntry::set_bytecode_2(Bytecodes::Code code) {

#ifdef ASSERT

  // Read once.

  volatile Bytecodes::Code c = bytecode_2();

  assert(c == 0 || c == code || code == 0, "update must be consistent");

#endif

  // Need to flush pending stores here before bytecode is written.

  OrderAccess::release_store_ptr(&_indices, _indices | ((u_char)code << 24));

}

// Atomically sets f1 if it is still NULL, otherwise it keeps the

// current value.

void ConstantPoolCacheEntry::set_f1_if_null_atomic(oop f1) {

  // Use barriers as in oop_store

  oop* f1_addr = (oop*) &_f1;

  update_barrier_set_pre(f1_addr, f1);

  void* result = Atomic::cmpxchg_ptr(f1, f1_addr, NULL);

  bool success = (result == NULL);

  if (success) {

    update_barrier_set((void*) f1_addr, f1);

  }

}

#ifdef ASSERT

// It is possible to have two different dummy methodOops created

// when the resolve code for invoke interface executes concurrently

// Hence the assertion below is weakened a bit for the invokeinterface

// case.

bool ConstantPoolCacheEntry::same_methodOop(oop cur_f1, oop f1) {

  return (cur_f1 == f1 || ((methodOop)cur_f1)->name() ==

         ((methodOop)f1)->name() || ((methodOop)cur_f1)->signature() ==

         ((methodOop)f1)->signature());

}

#endif

// Note that concurrent update of both bytecodes can leave one of them

// reset to zero.  This is harmless; the interpreter will simply re-resolve

// the damaged entry.  More seriously, the memory synchronization is needed

// to flush other fields (f1, f2) completely to memory before the bytecodes

// are updated, lest other processors see a non-zero bytecode but zero f1/f2.

void ConstantPoolCacheEntry::set_field(Bytecodes::Code get_code,

                                       Bytecodes::Code put_code,

                                       KlassHandle field_holder,

                                       int field_index,

                                       int field_offset,

                                       TosState field_type,

                                       bool is_final,

                                       bool is_volatile) {

  set_f1(field_holder()->java_mirror());

  set_f2(field_offset);

  assert(field_index <= field_index_mask,

         "field index does not fit in low flag bits");

  set_flags(as_flags(field_type, is_final, false, is_volatile, false, false) |

            (field_index & field_index_mask));

  set_bytecode_1(get_code);

  set_bytecode_2(put_code);

  NOT_PRODUCT(verify(tty));

}

int  ConstantPoolCacheEntry::field_index() const {

  return (_flags & field_index_mask);

}

void ConstantPoolCacheEntry::set_method(Bytecodes::Code invoke_code,

                                        methodHandle method,

                                        int vtable_index) {

  assert(!is_secondary_entry(), "");

  assert(method->interpreter_entry() != NULL, "should have been set at this point");

  assert(!method->is_obsolete(),  "attempt to write obsolete method to cpCache");

  bool change_to_virtual = (invoke_code == Bytecodes::_invokeinterface);

  int byte_no = -1;

  bool needs_vfinal_flag = false;

  switch (invoke_code) {

    case Bytecodes::_invokevirtual:

    case Bytecodes::_invokeinterface: {

        if (method->can_be_statically_bound()) {

          set_f2((intptr_t)method());

          needs_vfinal_flag = true;

        } else {

          assert(vtable_index >= 0, "valid index");

          set_f2(vtable_index);

        }

        byte_no = 2;

        break;

    }

    case Bytecodes::_invokedynamic:  // similar to _invokevirtual

      if (TraceInvokeDynamic) {

        tty->print_cr("InvokeDynamic set_method%s method="PTR_FORMAT" index=%d",

                      (is_secondary_entry() ? " secondary" : ""),

                      (intptr_t)method(), vtable_index);

        method->print();

        this->print(tty, 0);

      }

      assert(method->can_be_statically_bound(), "must be a MH invoker method");

      assert(_f2 >= constantPoolOopDesc::CPCACHE_INDEX_TAG, "BSM index initialized");

      // SystemDictionary::find_method_handle_invoke only caches

      // methods which signature classes are on the boot classpath,

      // otherwise the newly created method is returned.  To avoid

      // races in that case we store the first one coming in into the

      // cp-cache atomically if it's still unset.

      set_f1_if_null_atomic(method());

      needs_vfinal_flag = false;  // _f2 is not an oop

      assert(!is_vfinal(), "f2 not an oop");

      byte_no = 1;  // coordinate this with bytecode_number & is_resolved

      break;

    case Bytecodes::_invokespecial:

      // Preserve the value of the vfinal flag on invokevirtual bytecode

      // which may be shared with this constant pool cache entry.

      needs_vfinal_flag = is_resolved(Bytecodes::_invokevirtual) && is_vfinal();

      // fall through

    case Bytecodes::_invokestatic:

      set_f1(method());

      byte_no = 1;

      break;

    default:

      ShouldNotReachHere();

      break;

  }

  set_flags(as_flags(as_TosState(method->result_type()),

                     method->is_final_method(),

                     needs_vfinal_flag,

                     false,

                     change_to_virtual,

                     true)|

            method()->size_of_parameters());

  // Note:  byte_no also appears in TemplateTable::resolve.

  if (byte_no == 1) {

    set_bytecode_1(invoke_code);

  } else if (byte_no == 2)  {

    if (change_to_virtual) {

      // NOTE: THIS IS A HACK - BE VERY CAREFUL!!!

      //

      // Workaround for the case where we encounter an invokeinterface, but we

      // should really have an _invokevirtual since the resolved method is a

      // virtual method in java.lang.Object. This is a corner case in the spec

      // but is presumably legal. javac does not generate this code.

      //

      // We set bytecode_1() to _invokeinterface, because that is the

      // bytecode # used by the interpreter to see if it is resolved.

      // We set bytecode_2() to _invokevirtual.

      // See also interpreterRuntime.cpp. (8/25/2000)

      // Only set resolved for the invokeinterface case if method is public.

      // Otherwise, the method needs to be reresolved with caller for each

      // interface call.

      if (method->is_public()) set_bytecode_1(invoke_code);

      set_bytecode_2(Bytecodes::_invokevirtual);

    } else {

      set_bytecode_2(invoke_code);

    }

  } else {

    ShouldNotReachHere();

  }

  NOT_PRODUCT(verify(tty));

}

void ConstantPoolCacheEntry::set_interface_call(methodHandle method, int index) {

  assert(!is_secondary_entry(), "");

  klassOop interf = method->method_holder();

  assert(instanceKlass::cast(interf)->is_interface(), "must be an interface");

  set_f1(interf);

  set_f2(index);

  set_flags(as_flags(as_TosState(method->result_type()), method->is_final_method(), false, false, false, true) | method()->size_of_parameters());

  set_bytecode_1(Bytecodes::_invokeinterface);

}

void ConstantPoolCacheEntry::initialize_bootstrap_method_index_in_cache(int bsm_cache_index) {

  assert(!is_secondary_entry(), "only for JVM_CONSTANT_InvokeDynamic main entry");

  assert(_f2 == 0, "initialize once");

  assert(bsm_cache_index == (int)(u2)bsm_cache_index, "oob");

  set_f2(bsm_cache_index + constantPoolOopDesc::CPCACHE_INDEX_TAG);

}

int ConstantPoolCacheEntry::bootstrap_method_index_in_cache() {

  assert(!is_secondary_entry(), "only for JVM_CONSTANT_InvokeDynamic main entry");

  intptr_t bsm_cache_index = (intptr_t) _f2 - constantPoolOopDesc::CPCACHE_INDEX_TAG;

  assert(bsm_cache_index == (intptr_t)(u2)bsm_cache_index, "oob");

  return (int) bsm_cache_index;

}

void ConstantPoolCacheEntry::set_dynamic_call(Handle call_site, methodHandle signature_invoker) {

  assert(is_secondary_entry(), "");

  // NOTE: it's important that all other values are set before f1 is

  // set since some users short circuit on f1 being set

  // (i.e. non-null) and that may result in uninitialized values for

  // other racing threads (e.g. flags).

  int param_size = signature_invoker->size_of_parameters();

  assert(param_size >= 1, "method argument size must include MH.this");

  param_size -= 1;  // do not count MH.this; it is not stacked for invokedynamic

  bool is_final = true;

  assert(signature_invoker->is_final_method(), "is_final");

  int flags = as_flags(as_TosState(signature_invoker->result_type()), is_final, false, false, false, true) | param_size;

  assert(_flags == 0 || _flags == flags, "flags should be the same");

  set_flags(flags);

  // do not do set_bytecode on a secondary CP cache entry

  //set_bytecode_1(Bytecodes::_invokedynamic);

  set_f1_if_null_atomic(call_site());  // This must be the last one to set (see NOTE above)!

}

methodOop ConstantPoolCacheEntry::get_method_if_resolved(Bytecodes::Code invoke_code, constantPoolHandle cpool) {

  assert(invoke_code > (Bytecodes::Code)0, "bad query");

  if (is_secondary_entry()) {

    return cpool->cache()->entry_at(main_entry_index())->get_method_if_resolved(invoke_code, cpool);

  }

  // Decode the action of set_method and set_interface_call

  if (bytecode_1() == invoke_code) {

    oop f1 = _f1;

    if (f1 != NULL) {

      switch (invoke_code) {

      case Bytecodes::_invokeinterface:

        assert(f1->is_klass(), "");

        return klassItable::method_for_itable_index(klassOop(f1), (int) f2());

      case Bytecodes::_invokestatic:

      case Bytecodes::_invokespecial:

        assert(f1->is_method(), "");

        return methodOop(f1);

      }

    }

  }

  if (bytecode_2() == invoke_code) {

    switch (invoke_code) {

    case Bytecodes::_invokevirtual:

      if (is_vfinal()) {

        // invokevirtual

        methodOop m = methodOop((intptr_t) f2());

        assert(m->is_method(), "");

        return m;

      } else {

        int holder_index = cpool->uncached_klass_ref_index_at(constant_pool_index());

        if (cpool->tag_at(holder_index).is_klass()) {

          klassOop klass = cpool->resolved_klass_at(holder_index);

          if (!Klass::cast(klass)->oop_is_instance())

            klass = SystemDictionary::Object_klass();

          return instanceKlass::cast(klass)->method_at_vtable((int) f2());

        }

      }

    }

  }

  return NULL;

}

class LocalOopClosure: public OopClosure {

 private:

  void (*_f)(oop*);

 public:

  LocalOopClosure(void f(oop*))        { _f = f; }

  virtual void do_oop(oop* o)          { _f(o); }

  virtual void do_oop(narrowOop *o)    { ShouldNotReachHere(); }

};

void ConstantPoolCacheEntry::oops_do(void f(oop*)) {

  LocalOopClosure blk(f);

  oop_iterate(&blk);

}

void ConstantPoolCacheEntry::oop_iterate(OopClosure* blk) {

  assert(in_words(size()) == 4, "check code below - may need adjustment");

  // field[1] is always oop or NULL

  blk->do_oop((oop*)&_f1);

  if (is_vfinal()) {

    blk->do_oop((oop*)&_f2);

  }

}

void ConstantPoolCacheEntry::oop_iterate_m(OopClosure* blk, MemRegion mr) {

  assert(in_words(size()) == 4, "check code below - may need adjustment");

  // field[1] is always oop or NULL

  if (mr.contains((oop *)&_f1)) blk->do_oop((oop*)&_f1);

  if (is_vfinal()) {

    if (mr.contains((oop *)&_f2)) blk->do_oop((oop*)&_f2);

  }

}

void ConstantPoolCacheEntry::follow_contents() {

  assert(in_words(size()) == 4, "check code below - may need adjustment");

  // field[1] is always oop or NULL

  MarkSweep::mark_and_push((oop*)&_f1);

  if (is_vfinal()) {

    MarkSweep::mark_and_push((oop*)&_f2);

  }

}

#ifndef SERIALGC

void ConstantPoolCacheEntry::follow_contents(ParCompactionManager* cm) {

  assert(in_words(size()) == 4, "check code below - may need adjustment");

  // field[1] is always oop or NULL

  PSParallelCompact::mark_and_push(cm, (oop*)&_f1);

  if (is_vfinal()) {

    PSParallelCompact::mark_and_push(cm, (oop*)&_f2);

  }

}

#endif // SERIALGC

void ConstantPoolCacheEntry::adjust_pointers() {

  assert(in_words(size()) == 4, "check code below - may need adjustment");

  // field[1] is always oop or NULL

  MarkSweep::adjust_pointer((oop*)&_f1);

  if (is_vfinal()) {

    MarkSweep::adjust_pointer((oop*)&_f2);

  }

}

#ifndef SERIALGC

void ConstantPoolCacheEntry::update_pointers() {

  assert(in_words(size()) == 4, "check code below - may need adjustment");

  // field[1] is always oop or NULL

  PSParallelCompact::adjust_pointer((oop*)&_f1);

  if (is_vfinal()) {

    PSParallelCompact::adjust_pointer((oop*)&_f2);

  }

}

#endif // SERIALGC

// RedefineClasses() API support:

// If this constantPoolCacheEntry refers to old_method then update it

// to refer to new_method.

bool ConstantPoolCacheEntry::adjust_method_entry(methodOop old_method,

       methodOop new_method, bool * trace_name_printed) {

  if (is_vfinal()) {

    // virtual and final so f2() contains method ptr instead of vtable index

    if (f2() == (intptr_t)old_method) {

      // match old_method so need an update

      _f2 = (intptr_t)new_method;

      if (RC_TRACE_IN_RANGE(0x00100000, 0x00400000)) {

        if (!(*trace_name_printed)) {

          // RC_TRACE_MESG macro has an embedded ResourceMark

          RC_TRACE_MESG(("adjust: name=%s",

            Klass::cast(old_method->method_holder())->external_name()));

          *trace_name_printed = true;

        }

        // RC_TRACE macro has an embedded ResourceMark

        RC_TRACE(0x00400000, ("cpc vf-entry update: %s(%s)",

          new_method->name()->as_C_string(),

          new_method->signature()->as_C_string()));

      }

      return true;

    }

    // f1() is not used with virtual entries so bail out

    return false;

  }

  if ((oop)_f1 == NULL) {

    // NULL f1() means this is a virtual entry so bail out

    // We are assuming that the vtable index does not need change.

    return false;

  }

  if ((oop)_f1 == old_method) {

    _f1 = new_method;

    if (RC_TRACE_IN_RANGE(0x00100000, 0x00400000)) {

      if (!(*trace_name_printed)) {

        // RC_TRACE_MESG macro has an embedded ResourceMark

        RC_TRACE_MESG(("adjust: name=%s",

          Klass::cast(old_method->method_holder())->external_name()));

        *trace_name_printed = true;

      }

      // RC_TRACE macro has an embedded ResourceMark

      RC_TRACE(0x00400000, ("cpc entry update: %s(%s)",

        new_method->name()->as_C_string(),

        new_method->signature()->as_C_string()));

    }

    return true;

  }

  return false;

}

bool ConstantPoolCacheEntry::is_interesting_method_entry(klassOop k) {

  if (!is_method_entry()) {

    // not a method entry so not interesting by default

    return false;

  }

  methodOop m = NULL;

  if (is_vfinal()) {

    // virtual and final so _f2 contains method ptr instead of vtable index

    m = (methodOop)_f2;

  } else if ((oop)_f1 == NULL) {

    // NULL _f1 means this is a virtual entry so also not interesting

    return false;

  } else {

    if (!((oop)_f1)->is_method()) {

      // _f1 can also contain a klassOop for an interface

      return false;

    }

    m = (methodOop)_f1;

  }

  assert(m != NULL && m->is_method(), "sanity check");

  if (m == NULL || !m->is_method() || m->method_holder() != k) {

    // robustness for above sanity checks or method is not in

    // the interesting class

    return false;

  }

  // the method is in the interesting class so the entry is interesting

  return true;

}

void ConstantPoolCacheEntry::print(outputStream* st, int index) const {

  // print separator

  if (index == 0) st->print_cr("                 -------------");

  // print entry

  st->print("%3d  ("PTR_FORMAT")  ", index, (intptr_t)this);

  if (is_secondary_entry())

    st->print_cr("[%5d|secondary]", main_entry_index());

  else

    st->print_cr("[%02x|%02x|%5d]", bytecode_2(), bytecode_1(), constant_pool_index());

  st->print_cr("                 [   "PTR_FORMAT"]", (intptr_t)(oop)_f1);

  st->print_cr("                 [   "PTR_FORMAT"]", (intptr_t)_f2);