/*

 * Copyright (c) 1998, 2015, 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 "interpreter/interpreter.hpp"

#include "interpreter/rewriter.hpp"

#include "memory/universe.inline.hpp"

#include "oops/cpCache.hpp"

#include "oops/objArrayOop.inline.hpp"

#include "oops/oop.inline.hpp"

#include "prims/jvmtiRedefineClassesTrace.hpp"

#include "prims/methodHandles.hpp"

#include "runtime/atomic.inline.hpp"

#include "runtime/handles.inline.hpp"

#include "runtime/orderAccess.inline.hpp"

#include "utilities/macros.hpp"

PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC

// Implementation of ConstantPoolCacheEntry

void ConstantPoolCacheEntry::initialize_entry(int index) {

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

  _indices = index;

  _f1 = NULL;

  _f2 = _flags = 0;

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

}

int ConstantPoolCacheEntry::make_flags(TosState state,

                                       int option_bits,

                                       int field_index_or_method_params) {

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

  int f = ((int)state << tos_state_shift) | option_bits | field_index_or_method_params;

  // Preserve existing flag bit values

  // The low bits are a field offset, or else the method parameter size.

#ifdef ASSERT

  TosState old_state = flag_state();

  assert(old_state == (TosState)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 << bytecode_1_shift));

}

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 << bytecode_2_shift));

}

// Sets f1, ordering with previous writes.

void ConstantPoolCacheEntry::release_set_f1(Metadata* f1) {

  assert(f1 != NULL, "");

  OrderAccess::release_store_ptr((HeapWord*) &_f1, f1);

}

// Sets flags, but only if the value was previously zero.

bool ConstantPoolCacheEntry::init_flags_atomic(intptr_t flags) {

  intptr_t result = Atomic::cmpxchg_ptr(flags, &_flags, 0);

  return (result == 0);

}

// 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,

                                       Klass* root_klass) {

  set_f1(field_holder());

  set_f2(field_offset);

  assert((field_index & field_index_mask) == field_index,

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

  set_field_flags(field_type,

                  ((is_volatile ? 1 : 0) << is_volatile_shift) |

                  ((is_final    ? 1 : 0) << is_final_shift),

                  field_index);

  set_bytecode_1(get_code);

  set_bytecode_2(put_code);

  NOT_PRODUCT(verify(tty));

}

void ConstantPoolCacheEntry::set_parameter_size(int value) {

  // This routine is called only in corner cases where the CPCE is not yet initialized.

  // See AbstractInterpreter::deopt_continue_after_entry.

  assert(_flags == 0 || parameter_size() == 0 || parameter_size() == value,

  // Setting the parameter size by itself is only safe if the

  // current value of _flags is 0, otherwise another thread may have

  // updated it and we don't want to overwrite that value.  Don't

  // bother trying to update it once it's nonzero but always make

  // sure that the final parameter size agrees with what was passed.

  if (_flags == 0) {

    Atomic::cmpxchg_ptr((value & parameter_size_mask), &_flags, 0);

  }

  guarantee(parameter_size() == value,

}

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

                                                       methodHandle method,

                                                       int vtable_index) {

  bool is_vtable_call = (vtable_index >= 0);  // FIXME: split this method on this boolean

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

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

  int byte_no = -1;

  bool change_to_virtual = false;

  switch (invoke_code) {

    case Bytecodes::_invokeinterface:

      // We get here from InterpreterRuntime::resolve_invoke when an invokeinterface

      // instruction somehow links to a non-interface method (in Object).

      // In that case, the method has no itable index and must be invoked as a virtual.

      // Set a flag to keep track of this corner case.

      change_to_virtual = true;

      // ...and fall through as if we were handling invokevirtual:

    case Bytecodes::_invokevirtual:

      {

        if (!is_vtable_call) {

          assert(method->can_be_statically_bound(), "");

          // set_f2_as_vfinal_method checks if is_vfinal flag is true.

          set_method_flags(as_TosState(method->result_type()),

                           (                             1      << is_vfinal_shift) |

                           ((method->is_final_method() ? 1 : 0) << is_final_shift)  |

                           ((change_to_virtual         ? 1 : 0) << is_forced_virtual_shift),

                           method()->size_of_parameters());

          set_f2_as_vfinal_method(method());

        } else {

          assert(!method->can_be_statically_bound(), "");

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

          assert(!method->is_final_method(), "sanity");

          set_method_flags(as_TosState(method->result_type()),

                           ((change_to_virtual ? 1 : 0) << is_forced_virtual_shift),

                           method()->size_of_parameters());

          set_f2(vtable_index);

        }

        byte_no = 2;

        break;

      }

    case Bytecodes::_invokespecial:

    case Bytecodes::_invokestatic:

      assert(!is_vtable_call, "");

      // Note:  Read and preserve the value of the is_vfinal flag on any

      // invokevirtual bytecode shared with this constant pool cache entry.

      // It is cheap and safe to consult is_vfinal() at all times.

      // Once is_vfinal is set, it must stay that way, lest we get a dangling oop.

      set_method_flags(as_TosState(method->result_type()),

                       ((is_vfinal()               ? 1 : 0) << is_vfinal_shift) |

                       ((method->is_final_method() ? 1 : 0) << is_final_shift),

                       method()->size_of_parameters());

      set_f1(method());

      byte_no = 1;

      break;

    default:

      ShouldNotReachHere();

      break;

  }

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

  if (byte_no == 1) {

    assert(invoke_code != Bytecodes::_invokevirtual &&

           invoke_code != Bytecodes::_invokeinterface, "");

    set_bytecode_1(invoke_code);

  } else if (byte_no == 2)  {

    if (change_to_virtual) {

      assert(invoke_code == Bytecodes::_invokeinterface, "");

      // 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);

    } else {

      assert(invoke_code == Bytecodes::_invokevirtual, "");

    }

    // set up for invokevirtual, even if linking for invokeinterface also:

    set_bytecode_2(Bytecodes::_invokevirtual);

  } else {

    ShouldNotReachHere();

  }

  NOT_PRODUCT(verify(tty));

}

void ConstantPoolCacheEntry::set_direct_call(Bytecodes::Code invoke_code, methodHandle method) {

  int index = Method::nonvirtual_vtable_index;

  // index < 0; FIXME: inline and customize set_direct_or_vtable_call

  set_direct_or_vtable_call(invoke_code, method, index);

}

void ConstantPoolCacheEntry::set_vtable_call(Bytecodes::Code invoke_code, methodHandle method, int index) {

  // either the method is a miranda or its holder should accept the given index

  assert(method->method_holder()->is_interface() || method->method_holder()->verify_vtable_index(index), "");

  // index >= 0; FIXME: inline and customize set_direct_or_vtable_call

  set_direct_or_vtable_call(invoke_code, method, index);

}

void ConstantPoolCacheEntry::set_itable_call(Bytecodes::Code invoke_code, methodHandle method, int index) {

  assert(method->method_holder()->verify_itable_index(index), "");

  assert(invoke_code == Bytecodes::_invokeinterface, "");

  InstanceKlass* interf = method->method_holder();

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

  assert(!method->is_final_method(), "interfaces do not have final methods; cannot link to one here");

  set_f1(interf);

  set_f2(index);

  set_method_flags(as_TosState(method->result_type()),

                   0,  // no option bits

                   method()->size_of_parameters());

  set_bytecode_1(Bytecodes::_invokeinterface);

}

void ConstantPoolCacheEntry::set_method_handle(constantPoolHandle cpool, const CallInfo &call_info) {

  set_method_handle_common(cpool, Bytecodes::_invokehandle, call_info);

}

void ConstantPoolCacheEntry::set_dynamic_call(constantPoolHandle cpool, const CallInfo &call_info) {

  set_method_handle_common(cpool, Bytecodes::_invokedynamic, call_info);

}

void ConstantPoolCacheEntry::set_method_handle_common(constantPoolHandle cpool,

                                                      Bytecodes::Code invoke_code,

                                                      const CallInfo &call_info) {

  // NOTE: This CPCE can be the subject of data races.

  // There are three words to update: flags, refs[f2], f1 (in that order).

  // Writers must store all other values before f1.

  // Readers must test f1 first for non-null before reading other fields.

  // Competing writers must acquire exclusive access via a lock.

  // A losing writer waits on the lock until the winner writes f1 and leaves

  // the lock, so that when the losing writer returns, he can use the linked

  // cache entry.

  objArrayHandle resolved_references = cpool->resolved_references();

  // Use the resolved_references() lock for this cpCache entry.

  // resolved_references are created for all classes with Invokedynamic, MethodHandle

  // or MethodType constant pool cache entries.

  assert(resolved_references() != NULL,

         "a resolved_references array should have been created for this class");

  ObjectLocker ol(resolved_references, Thread::current());

  if (!is_f1_null()) {

    return;

  }

  const methodHandle adapter = call_info.resolved_method();

  const Handle appendix      = call_info.resolved_appendix();

  const Handle method_type   = call_info.resolved_method_type();

  const bool has_appendix    = appendix.not_null();

  const bool has_method_type = method_type.not_null();

  // Write the flags.

  set_method_flags(as_TosState(adapter->result_type()),

                   ((has_appendix    ? 1 : 0) << has_appendix_shift   ) |

                   ((has_method_type ? 1 : 0) << has_method_type_shift) |

                   (                   1      << is_final_shift       ),

                   adapter->size_of_parameters());

  if (TraceInvokeDynamic) {

    tty->print_cr("set_method_handle bc=%d appendix=" PTR_FORMAT "%s method_type=" PTR_FORMAT "%s method=" PTR_FORMAT " ",

                  invoke_code,

                  (void *)appendix(),    (has_appendix    ? "" : " (unused)"),

                  (void *)method_type(), (has_method_type ? "" : " (unused)"),

                  (intptr_t)adapter());

    adapter->print();

    if (has_appendix)  appendix()->print();

  }

  // Method handle invokes and invokedynamic sites use both cp cache words.

  // refs[f2], if not null, contains a value passed as a trailing argument to the adapter.

  // In the general case, this could be the call site's MethodType,

  // for use with java.lang.Invokers.checkExactType, or else a CallSite object.

  // f1 contains the adapter method which manages the actual call.

  // In the general case, this is a compiled LambdaForm.

  // (The Java code is free to optimize these calls by binding other

  // sorts of methods and appendices to call sites.)

  // JVM-level linking is via f1, as if for invokespecial, and signatures are erased.

  // The appendix argument (if any) is added to the signature, and is counted in the parameter_size bits.

  // Even with the appendix, the method will never take more than 255 parameter slots.

  //

  // This means that given a call site like (List)mh.invoke("foo"),

  // the f1 method has signature '(Ljl/Object;Ljl/invoke/MethodType;)Ljl/Object;',

  // not '(Ljava/lang/String;)Ljava/util/List;'.

  // The fact that String and List are involved is encoded in the MethodType in refs[f2].

  // This allows us to create fewer Methods, while keeping type safety.

  //

  // Store appendix, if any.

  if (has_appendix) {

    const int appendix_index = f2_as_index() + _indy_resolved_references_appendix_offset;

    assert(appendix_index >= 0 && appendix_index < resolved_references->length(), "oob");

    assert(resolved_references->obj_at(appendix_index) == NULL, "init just once");

    resolved_references->obj_at_put(appendix_index, appendix());

  }

  // Store MethodType, if any.

  if (has_method_type) {

    const int method_type_index = f2_as_index() + _indy_resolved_references_method_type_offset;

    assert(method_type_index >= 0 && method_type_index < resolved_references->length(), "oob");

    assert(resolved_references->obj_at(method_type_index) == NULL, "init just once");

    resolved_references->obj_at_put(method_type_index, method_type());

  }

  release_set_f1(adapter());  // This must be the last one to set (see NOTE above)!

  // The interpreter assembly code does not check byte_2,

  // but it is used by is_resolved, method_if_resolved, etc.

  set_bytecode_1(invoke_code);

  NOT_PRODUCT(verify(tty));

  if (TraceInvokeDynamic) {

    this->print(tty, 0);

  }

}

Method* ConstantPoolCacheEntry::method_if_resolved(constantPoolHandle cpool) {

  // Decode the action of set_method and set_interface_call

  Bytecodes::Code invoke_code = bytecode_1();

  if (invoke_code != (Bytecodes::Code)0) {

    Metadata* f1 = f1_ord();

    if (f1 != NULL) {

      switch (invoke_code) {

      case Bytecodes::_invokeinterface:

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

        return klassItable::method_for_itable_index((Klass*)f1, f2_as_index());

      case Bytecodes::_invokestatic:

      case Bytecodes::_invokespecial:

        assert(!has_appendix(), "");

      case Bytecodes::_invokehandle:

      case Bytecodes::_invokedynamic:

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

        return (Method*)f1;

      }

    }

  }

  invoke_code = bytecode_2();

  if (invoke_code != (Bytecodes::Code)0) {

    switch (invoke_code) {

    case Bytecodes::_invokevirtual:

      if (is_vfinal()) {

        // invokevirtual

        Method* m = f2_as_vfinal_method();

        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()) {

          Klass* klass = cpool->resolved_klass_at(holder_index);

          if (!klass->oop_is_instance())

            klass = SystemDictionary::Object_klass();

          return InstanceKlass::cast(klass)->method_at_vtable(f2_as_index());

        }

      }

      break;

    }

  }

  return NULL;

}

oop ConstantPoolCacheEntry::appendix_if_resolved(constantPoolHandle cpool) {

  if (!has_appendix())

    return NULL;

  const int ref_index = f2_as_index() + _indy_resolved_references_appendix_offset;

  objArrayOop resolved_references = cpool->resolved_references();

  return resolved_references->obj_at(ref_index);

}

oop ConstantPoolCacheEntry::method_type_if_resolved(constantPoolHandle cpool) {

  if (!has_method_type())

    return NULL;

  const int ref_index = f2_as_index() + _indy_resolved_references_method_type_offset;

  objArrayOop resolved_references = cpool->resolved_references();

  return resolved_references->obj_at(ref_index);

}

#if INCLUDE_JVMTI

// RedefineClasses() API support:

// If this ConstantPoolCacheEntry refers to old_method then update it

// to refer to new_method.

bool ConstantPoolCacheEntry::adjust_method_entry(Method* old_method,

       Method* new_method, bool * trace_name_printed) {

  if (is_vfinal()) {

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

    if (f2_as_vfinal_method() == old_method) {

      // match old_method so need an update

      // NOTE: can't use set_f2_as_vfinal_method as it asserts on different values

      _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",

            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 (_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 (_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",

          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;

}

// a constant pool cache entry should never contain old or obsolete methods

bool ConstantPoolCacheEntry::check_no_old_or_obsolete_entries() {

  if (is_vfinal()) {

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

    Metadata* f2 = (Metadata*)_f2;

    // Return false if _f2 refers to an old or an obsolete method.

    // _f2 == NULL || !_f2->is_method() are just as unexpected here.

    return (f2 != NULL NOT_PRODUCT(&& f2->is_valid()) && f2->is_method() &&

            !((Method*)f2)->is_old() && !((Method*)f2)->is_obsolete());