view src/cpu/zero/vm/cppInterpreter_zero.cpp @ 2352:e1162778c1c8

7009266: G1: assert(obj->is_oop_or_null(true )) failed: Error Summary: A referent object that is only weakly reachable at the start of concurrent marking but is re-attached to the strongly reachable object graph during marking may not be marked as live. This can cause the reference object to be processed prematurely and leave dangling pointers to the referent object. Implement a read barrier for the java.lang.ref.Reference::referent field by intrinsifying the Reference.get() method, and intercepting accesses though JNI, reflection, and Unsafe, so that when a non-null referent object is read it is also logged in an SATB buffer. Reviewed-by: kvn, iveresov, never, tonyp, dholmes
author johnc
date Thu, 07 Apr 2011 09:53:20 -0700
parents c7f3d0b4570f
children 732454aaf5cb
line wrap: on
line source
/*
 * Copyright (c) 2003, 2011, Oracle and/or its affiliates. All rights reserved.
 * Copyright 2007, 2008, 2009, 2010 Red Hat, Inc.
 * 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 "asm/assembler.hpp"
#include "interpreter/bytecodeHistogram.hpp"
#include "interpreter/cppInterpreter.hpp"
#include "interpreter/interpreter.hpp"
#include "interpreter/interpreterGenerator.hpp"
#include "interpreter/interpreterRuntime.hpp"
#include "oops/arrayOop.hpp"
#include "oops/methodDataOop.hpp"
#include "oops/methodOop.hpp"
#include "oops/oop.inline.hpp"
#include "prims/jvmtiExport.hpp"
#include "prims/jvmtiThreadState.hpp"
#include "runtime/arguments.hpp"
#include "runtime/deoptimization.hpp"
#include "runtime/frame.inline.hpp"
#include "runtime/interfaceSupport.hpp"
#include "runtime/sharedRuntime.hpp"
#include "runtime/stubRoutines.hpp"
#include "runtime/synchronizer.hpp"
#include "runtime/timer.hpp"
#include "runtime/vframeArray.hpp"
#include "stack_zero.inline.hpp"
#include "utilities/debug.hpp"
#ifdef SHARK
#include "shark/shark_globals.hpp"
#endif

#ifdef CC_INTERP

#define fixup_after_potential_safepoint()       \
  method = istate->method()

#define CALL_VM_NOCHECK(func)                   \
  thread->set_last_Java_frame();                \
  func;                                         \
  thread->reset_last_Java_frame();              \
  fixup_after_potential_safepoint()

int CppInterpreter::normal_entry(methodOop method, intptr_t UNUSED, TRAPS) {
  JavaThread *thread = (JavaThread *) THREAD;

  // Allocate and initialize our frame.
  InterpreterFrame *frame = InterpreterFrame::build(method, CHECK_0);
  thread->push_zero_frame(frame);

  // Execute those bytecodes!
  main_loop(0, THREAD);

  // No deoptimized frames on the stack
  return 0;
}

void CppInterpreter::main_loop(int recurse, TRAPS) {
  JavaThread *thread = (JavaThread *) THREAD;
  ZeroStack *stack = thread->zero_stack();

  // If we are entering from a deopt we may need to call
  // ourself a few times in order to get to our frame.
  if (recurse)
    main_loop(recurse - 1, THREAD);

  InterpreterFrame *frame = thread->top_zero_frame()->as_interpreter_frame();
  interpreterState istate = frame->interpreter_state();
  methodOop method = istate->method();

  intptr_t *result = NULL;
  int result_slots = 0;

  while (true) {
    // We can set up the frame anchor with everything we want at
    // this point as we are thread_in_Java and no safepoints can
    // occur until we go to vm mode.  We do have to clear flags
    // on return from vm but that is it.
    thread->set_last_Java_frame();

    // Call the interpreter
    if (JvmtiExport::can_post_interpreter_events())
      BytecodeInterpreter::runWithChecks(istate);
    else
      BytecodeInterpreter::run(istate);
    fixup_after_potential_safepoint();

    // Clear the frame anchor
    thread->reset_last_Java_frame();

    // Examine the message from the interpreter to decide what to do
    if (istate->msg() == BytecodeInterpreter::call_method) {
      methodOop callee = istate->callee();

      // Trim back the stack to put the parameters at the top
      stack->set_sp(istate->stack() + 1);

      // Make the call
      Interpreter::invoke_method(callee, istate->callee_entry_point(), THREAD);
      fixup_after_potential_safepoint();

      // Convert the result
      istate->set_stack(stack->sp() - 1);

      // Restore the stack
      stack->set_sp(istate->stack_limit() + 1);

      // Resume the interpreter
      istate->set_msg(BytecodeInterpreter::method_resume);
    }
    else if (istate->msg() == BytecodeInterpreter::more_monitors) {
      int monitor_words = frame::interpreter_frame_monitor_size();

      // Allocate the space
      stack->overflow_check(monitor_words, THREAD);
      if (HAS_PENDING_EXCEPTION)
        break;
      stack->alloc(monitor_words * wordSize);

      // Move the expression stack contents
      for (intptr_t *p = istate->stack() + 1; p < istate->stack_base(); p++)
        *(p - monitor_words) = *p;

      // Move the expression stack pointers
      istate->set_stack_limit(istate->stack_limit() - monitor_words);
      istate->set_stack(istate->stack() - monitor_words);
      istate->set_stack_base(istate->stack_base() - monitor_words);

      // Zero the new monitor so the interpreter can find it.
      ((BasicObjectLock *) istate->stack_base())->set_obj(NULL);

      // Resume the interpreter
      istate->set_msg(BytecodeInterpreter::got_monitors);
    }
    else if (istate->msg() == BytecodeInterpreter::return_from_method) {
      // Copy the result into the caller's frame
      result_slots = type2size[result_type_of(method)];
      assert(result_slots >= 0 && result_slots <= 2, "what?");
      result = istate->stack() + result_slots;
      break;
    }
    else if (istate->msg() == BytecodeInterpreter::throwing_exception) {
      assert(HAS_PENDING_EXCEPTION, "should do");
      break;
    }
    else if (istate->msg() == BytecodeInterpreter::do_osr) {
      // Unwind the current frame
      thread->pop_zero_frame();

      // Remove any extension of the previous frame
      int extra_locals = method->max_locals() - method->size_of_parameters();
      stack->set_sp(stack->sp() + extra_locals);

      // Jump into the OSR method
      Interpreter::invoke_osr(
        method, istate->osr_entry(), istate->osr_buf(), THREAD);
      return;
    }
    else {
      ShouldNotReachHere();
    }
  }

  // Unwind the current frame
  thread->pop_zero_frame();

  // Pop our local variables
  stack->set_sp(stack->sp() + method->max_locals());

  // Push our result
  for (int i = 0; i < result_slots; i++)
    stack->push(result[-i]);
}

int CppInterpreter::native_entry(methodOop method, intptr_t UNUSED, TRAPS) {
  // Make sure method is native and not abstract
  assert(method->is_native() && !method->is_abstract(), "should be");

  JavaThread *thread = (JavaThread *) THREAD;
  ZeroStack *stack = thread->zero_stack();

  // Allocate and initialize our frame
  InterpreterFrame *frame = InterpreterFrame::build(method, CHECK_0);
  thread->push_zero_frame(frame);
  interpreterState istate = frame->interpreter_state();
  intptr_t *locals = istate->locals();

  // Update the invocation counter
  if ((UseCompiler || CountCompiledCalls) && !method->is_synchronized()) {
    InvocationCounter *counter = method->invocation_counter();
    counter->increment();
    if (counter->reached_InvocationLimit()) {
      CALL_VM_NOCHECK(
        InterpreterRuntime::frequency_counter_overflow(thread, NULL));
      if (HAS_PENDING_EXCEPTION)
        goto unwind_and_return;
    }
  }

  // Lock if necessary
  BasicObjectLock *monitor;
  monitor = NULL;
  if (method->is_synchronized()) {
    monitor = (BasicObjectLock*) istate->stack_base();
    oop lockee = monitor->obj();
    markOop disp = lockee->mark()->set_unlocked();

    monitor->lock()->set_displaced_header(disp);
    if (Atomic::cmpxchg_ptr(monitor, lockee->mark_addr(), disp) != disp) {
      if (thread->is_lock_owned((address) disp->clear_lock_bits())) {
        monitor->lock()->set_displaced_header(NULL);
      }
      else {
        CALL_VM_NOCHECK(InterpreterRuntime::monitorenter(thread, monitor));
        if (HAS_PENDING_EXCEPTION)
          goto unwind_and_return;
      }
    }
  }

  // Get the signature handler
  InterpreterRuntime::SignatureHandler *handler; {
    address handlerAddr = method->signature_handler();
    if (handlerAddr == NULL) {
      CALL_VM_NOCHECK(InterpreterRuntime::prepare_native_call(thread, method));
      if (HAS_PENDING_EXCEPTION)
        goto unlock_unwind_and_return;

      handlerAddr = method->signature_handler();
      assert(handlerAddr != NULL, "eh?");
    }
    if (handlerAddr == (address) InterpreterRuntime::slow_signature_handler) {
      CALL_VM_NOCHECK(handlerAddr =
        InterpreterRuntime::slow_signature_handler(thread, method, NULL,NULL));
      if (HAS_PENDING_EXCEPTION)
        goto unlock_unwind_and_return;
    }
    handler = \
      InterpreterRuntime::SignatureHandler::from_handlerAddr(handlerAddr);
  }

  // Get the native function entry point
  address function;
  function = method->native_function();
  assert(function != NULL, "should be set if signature handler is");

  // Build the argument list
  stack->overflow_check(handler->argument_count() * 2, THREAD);
  if (HAS_PENDING_EXCEPTION)
    goto unlock_unwind_and_return;

  void **arguments;
  void *mirror; {
    arguments =
      (void **) stack->alloc(handler->argument_count() * sizeof(void **));
    void **dst = arguments;

    void *env = thread->jni_environment();
    *(dst++) = &env;

    if (method->is_static()) {
      istate->set_oop_temp(
        method->constants()->pool_holder()->java_mirror());
      mirror = istate->oop_temp_addr();
      *(dst++) = &mirror;
    }

    intptr_t *src = locals;
    for (int i = dst - arguments; i < handler->argument_count(); i++) {
      ffi_type *type = handler->argument_type(i);
      if (type == &ffi_type_pointer) {
        if (*src) {
          stack->push((intptr_t) src);
          *(dst++) = stack->sp();
        }
        else {
          *(dst++) = src;
        }
        src--;
      }
      else if (type->size == 4) {
        *(dst++) = src--;
      }
      else if (type->size == 8) {
        src--;
        *(dst++) = src--;
      }
      else {
        ShouldNotReachHere();
      }
    }
  }

  // Set up the Java frame anchor
  thread->set_last_Java_frame();

  // Change the thread state to _thread_in_native
  ThreadStateTransition::transition_from_java(thread, _thread_in_native);

  // Make the call
  intptr_t result[4 - LogBytesPerWord];
  ffi_call(handler->cif(), (void (*)()) function, result, arguments);

  // Change the thread state back to _thread_in_Java.
  // ThreadStateTransition::transition_from_native() cannot be used
  // here because it does not check for asynchronous exceptions.
  // We have to manage the transition ourself.
  thread->set_thread_state(_thread_in_native_trans);

  // Make sure new state is visible in the GC thread
  if (os::is_MP()) {
    if (UseMembar) {
      OrderAccess::fence();
    }
    else {
      InterfaceSupport::serialize_memory(thread);
    }
  }

  // Handle safepoint operations, pending suspend requests,
  // and pending asynchronous exceptions.
  if (SafepointSynchronize::do_call_back() ||
      thread->has_special_condition_for_native_trans()) {
    JavaThread::check_special_condition_for_native_trans(thread);
    CHECK_UNHANDLED_OOPS_ONLY(thread->clear_unhandled_oops());
  }

  // Finally we can change the thread state to _thread_in_Java.
  thread->set_thread_state(_thread_in_Java);
  fixup_after_potential_safepoint();

  // Clear the frame anchor
  thread->reset_last_Java_frame();

  // If the result was an oop then unbox it and store it in
  // oop_temp where the garbage collector can see it before
  // we release the handle it might be protected by.
  if (handler->result_type() == &ffi_type_pointer) {
    if (result[0])
      istate->set_oop_temp(*(oop *) result[0]);
    else
      istate->set_oop_temp(NULL);
  }

  // Reset handle block
  thread->active_handles()->clear();

 unlock_unwind_and_return:

  // Unlock if necessary
  if (monitor) {
    BasicLock *lock = monitor->lock();
    markOop header = lock->displaced_header();
    oop rcvr = monitor->obj();
    monitor->set_obj(NULL);

    if (header != NULL) {
      if (Atomic::cmpxchg_ptr(header, rcvr->mark_addr(), lock) != lock) {
        monitor->set_obj(rcvr); {
          HandleMark hm(thread);
          CALL_VM_NOCHECK(InterpreterRuntime::monitorexit(thread, monitor));
        }
      }
    }
  }

 unwind_and_return:

  // Unwind the current activation
  thread->pop_zero_frame();

  // Pop our parameters
  stack->set_sp(stack->sp() + method->size_of_parameters());

  // Push our result
  if (!HAS_PENDING_EXCEPTION) {
    BasicType type = result_type_of(method);
    stack->set_sp(stack->sp() - type2size[type]);

    switch (type) {
    case T_VOID:
      break;

    case T_BOOLEAN:
#ifndef VM_LITTLE_ENDIAN
      result[0] <<= (BitsPerWord - BitsPerByte);
#endif
      SET_LOCALS_INT(*(jboolean *) result != 0, 0);
      break;

    case T_CHAR:
#ifndef VM_LITTLE_ENDIAN
      result[0] <<= (BitsPerWord - BitsPerShort);
#endif
      SET_LOCALS_INT(*(jchar *) result, 0);
      break;

    case T_BYTE:
#ifndef VM_LITTLE_ENDIAN
      result[0] <<= (BitsPerWord - BitsPerByte);
#endif
      SET_LOCALS_INT(*(jbyte *) result, 0);
      break;

    case T_SHORT:
#ifndef VM_LITTLE_ENDIAN
      result[0] <<= (BitsPerWord - BitsPerShort);
#endif
      SET_LOCALS_INT(*(jshort *) result, 0);
      break;

    case T_INT:
#ifndef VM_LITTLE_ENDIAN
      result[0] <<= (BitsPerWord - BitsPerInt);
#endif
      SET_LOCALS_INT(*(jint *) result, 0);
      break;

    case T_LONG:
      SET_LOCALS_LONG(*(jlong *) result, 0);
      break;

    case T_FLOAT:
      SET_LOCALS_FLOAT(*(jfloat *) result, 0);
      break;

    case T_DOUBLE:
      SET_LOCALS_DOUBLE(*(jdouble *) result, 0);
      break;

    case T_OBJECT:
    case T_ARRAY:
      SET_LOCALS_OBJECT(istate->oop_temp(), 0);
      break;

    default:
      ShouldNotReachHere();
    }
  }

  // No deoptimized frames on the stack
  return 0;
}

int CppInterpreter::accessor_entry(methodOop method, intptr_t UNUSED, TRAPS) {
  JavaThread *thread = (JavaThread *) THREAD;
  ZeroStack *stack = thread->zero_stack();
  intptr_t *locals = stack->sp();

  // Drop into the slow path if we need a safepoint check
  if (SafepointSynchronize::do_call_back()) {
    return normal_entry(method, 0, THREAD);
  }

  // Load the object pointer and drop into the slow path
  // if we have a NullPointerException
  oop object = LOCALS_OBJECT(0);
  if (object == NULL) {
    return normal_entry(method, 0, THREAD);
  }

  // Read the field index from the bytecode, which looks like this:
  //  0:  aload_0
  //  1:  getfield
  //  2:    index
  //  3:    index
  //  4:  ireturn/areturn
  // NB this is not raw bytecode: index is in machine order
  u1 *code = method->code_base();
  assert(code[0] == Bytecodes::_aload_0 &&
         code[1] == Bytecodes::_getfield &&
         (code[4] == Bytecodes::_ireturn ||
          code[4] == Bytecodes::_areturn), "should do");
  u2 index = Bytes::get_native_u2(&code[2]);

  // Get the entry from the constant pool cache, and drop into
  // the slow path if it has not been resolved
  constantPoolCacheOop cache = method->constants()->cache();
  ConstantPoolCacheEntry* entry = cache->entry_at(index);
  if (!entry->is_resolved(Bytecodes::_getfield)) {
    return normal_entry(method, 0, THREAD);
  }

  // Get the result and push it onto the stack
  switch (entry->flag_state()) {
  case ltos:
  case dtos:
    stack->overflow_check(1, CHECK_0);
    stack->alloc(wordSize);
    break;
  }
  if (entry->is_volatile()) {
    switch (entry->flag_state()) {
    case ctos:
      SET_LOCALS_INT(object->char_field_acquire(entry->f2()), 0);
      break;

    case btos:
      SET_LOCALS_INT(object->byte_field_acquire(entry->f2()), 0);
      break;

    case stos:
      SET_LOCALS_INT(object->short_field_acquire(entry->f2()), 0);
      break;

    case itos:
      SET_LOCALS_INT(object->int_field_acquire(entry->f2()), 0);
      break;

    case ltos:
      SET_LOCALS_LONG(object->long_field_acquire(entry->f2()), 0);
      break;

    case ftos:
      SET_LOCALS_FLOAT(object->float_field_acquire(entry->f2()), 0);
      break;

    case dtos:
      SET_LOCALS_DOUBLE(object->double_field_acquire(entry->f2()), 0);
      break;

    case atos:
      SET_LOCALS_OBJECT(object->obj_field_acquire(entry->f2()), 0);
      break;

    default:
      ShouldNotReachHere();
    }
  }
  else {
    switch (entry->flag_state()) {
    case ctos:
      SET_LOCALS_INT(object->char_field(entry->f2()), 0);
      break;

    case btos:
      SET_LOCALS_INT(object->byte_field(entry->f2()), 0);
      break;

    case stos:
      SET_LOCALS_INT(object->short_field(entry->f2()), 0);
      break;

    case itos:
      SET_LOCALS_INT(object->int_field(entry->f2()), 0);
      break;

    case ltos:
      SET_LOCALS_LONG(object->long_field(entry->f2()), 0);
      break;

    case ftos:
      SET_LOCALS_FLOAT(object->float_field(entry->f2()), 0);
      break;

    case dtos:
      SET_LOCALS_DOUBLE(object->double_field(entry->f2()), 0);
      break;

    case atos:
      SET_LOCALS_OBJECT(object->obj_field(entry->f2()), 0);
      break;

    default:
      ShouldNotReachHere();
    }
  }

  // No deoptimized frames on the stack
  return 0;
}

int CppInterpreter::empty_entry(methodOop method, intptr_t UNUSED, TRAPS) {
  JavaThread *thread = (JavaThread *) THREAD;
  ZeroStack *stack = thread->zero_stack();

  // Drop into the slow path if we need a safepoint check
  if (SafepointSynchronize::do_call_back()) {
    return normal_entry(method, 0, THREAD);
  }

  // Pop our parameters
  stack->set_sp(stack->sp() + method->size_of_parameters());

  // No deoptimized frames on the stack
  return 0;
}

InterpreterFrame *InterpreterFrame::build(const methodOop method, TRAPS) {
  JavaThread *thread = (JavaThread *) THREAD;
  ZeroStack *stack = thread->zero_stack();

  // Calculate the size of the frame we'll build, including
  // any adjustments to the caller's frame that we'll make.
  int extra_locals  = 0;
  int monitor_words = 0;
  int stack_words   = 0;

  if (!method->is_native()) {
    extra_locals = method->max_locals() - method->size_of_parameters();
    stack_words  = method->max_stack();
  }
  if (method->is_synchronized()) {
    monitor_words = frame::interpreter_frame_monitor_size();
  }
  stack->overflow_check(
    extra_locals + header_words + monitor_words + stack_words, CHECK_NULL);

  // Adjust the caller's stack frame to accomodate any additional
  // local variables we have contiguously with our parameters.
  for (int i = 0; i < extra_locals; i++)
    stack->push(0);

  intptr_t *locals;
  if (method->is_native())
    locals = stack->sp() + (method->size_of_parameters() - 1);
  else
    locals = stack->sp() + (method->max_locals() - 1);

  stack->push(0); // next_frame, filled in later
  intptr_t *fp = stack->sp();
  assert(fp - stack->sp() == next_frame_off, "should be");

  stack->push(INTERPRETER_FRAME);
  assert(fp - stack->sp() == frame_type_off, "should be");

  interpreterState istate =
    (interpreterState) stack->alloc(sizeof(BytecodeInterpreter));
  assert(fp - stack->sp() == istate_off, "should be");

  istate->set_locals(locals);
  istate->set_method(method);
  istate->set_self_link(istate);
  istate->set_prev_link(NULL);
  istate->set_thread(thread);
  istate->set_bcp(method->is_native() ? NULL : method->code_base());
  istate->set_constants(method->constants()->cache());
  istate->set_msg(BytecodeInterpreter::method_entry);
  istate->set_oop_temp(NULL);
  istate->set_mdx(NULL);
  istate->set_callee(NULL);

  istate->set_monitor_base((BasicObjectLock *) stack->sp());
  if (method->is_synchronized()) {
    BasicObjectLock *monitor =
      (BasicObjectLock *) stack->alloc(monitor_words * wordSize);
    oop object;
    if (method->is_static())
      object = method->constants()->pool_holder()->java_mirror();
    else
      object = (oop) locals[0];
    monitor->set_obj(object);
  }

  istate->set_stack_base(stack->sp());
  istate->set_stack(stack->sp() - 1);
  if (stack_words)
    stack->alloc(stack_words * wordSize);
  istate->set_stack_limit(stack->sp() - 1);

  return (InterpreterFrame *) fp;
}

int AbstractInterpreter::BasicType_as_index(BasicType type) {
  int i = 0;
  switch (type) {
    case T_BOOLEAN: i = 0; break;
    case T_CHAR   : i = 1; break;
    case T_BYTE   : i = 2; break;
    case T_SHORT  : i = 3; break;
    case T_INT    : i = 4; break;
    case T_LONG   : i = 5; break;
    case T_VOID   : i = 6; break;
    case T_FLOAT  : i = 7; break;
    case T_DOUBLE : i = 8; break;
    case T_OBJECT : i = 9; break;
    case T_ARRAY  : i = 9; break;
    default       : ShouldNotReachHere();
  }
  assert(0 <= i && i < AbstractInterpreter::number_of_result_handlers,
         "index out of bounds");
  return i;
}

BasicType CppInterpreter::result_type_of(methodOop method) {
  BasicType t;
  switch (method->result_index()) {
    case 0 : t = T_BOOLEAN; break;
    case 1 : t = T_CHAR;    break;
    case 2 : t = T_BYTE;    break;
    case 3 : t = T_SHORT;   break;
    case 4 : t = T_INT;     break;
    case 5 : t = T_LONG;    break;
    case 6 : t = T_VOID;    break;
    case 7 : t = T_FLOAT;   break;
    case 8 : t = T_DOUBLE;  break;
    case 9 : t = T_OBJECT;  break;
    default: ShouldNotReachHere();
  }
  assert(AbstractInterpreter::BasicType_as_index(t) == method->result_index(),
         "out of step with AbstractInterpreter::BasicType_as_index");
  return t;
}

address InterpreterGenerator::generate_empty_entry() {
  if (!UseFastEmptyMethods)
    return NULL;

  return generate_entry((address) CppInterpreter::empty_entry);
}

address InterpreterGenerator::generate_accessor_entry() {
  if (!UseFastAccessorMethods)
    return NULL;

  return generate_entry((address) CppInterpreter::accessor_entry);
}

address InterpreterGenerator::generate_Reference_get_entry(void) {
#ifndef SERIALGC
  if (UseG1GC) {
    // We need to generate have a routine that generates code to:
    //   * load the value in the referent field
    //   * passes that value to the pre-barrier.
    //
    // In the case of G1 this will record the value of the
    // referent in an SATB buffer if marking is active.
    // This will cause concurrent marking to mark the referent
    // field as live.
    Unimplemented();
  }
#endif // SERIALGC

  // If G1 is not enabled then attempt to go through the accessor entry point
  // Reference.get is an accessor
  return generate_accessor_entry();
}

address InterpreterGenerator::generate_native_entry(bool synchronized) {
  assert(synchronized == false, "should be");

  return generate_entry((address) CppInterpreter::native_entry);
}

address InterpreterGenerator::generate_normal_entry(bool synchronized) {
  assert(synchronized == false, "should be");

  return generate_entry((address) CppInterpreter::normal_entry);
}

address AbstractInterpreterGenerator::generate_method_entry(
    AbstractInterpreter::MethodKind kind) {
  address entry_point = NULL;

  switch (kind) {
  case Interpreter::zerolocals:
  case Interpreter::zerolocals_synchronized:
    break;

  case Interpreter::native:
    entry_point = ((InterpreterGenerator*) this)->generate_native_entry(false);
    break;

  case Interpreter::native_synchronized:
    entry_point = ((InterpreterGenerator*) this)->generate_native_entry(false);
    break;

  case Interpreter::empty:
    entry_point = ((InterpreterGenerator*) this)->generate_empty_entry();
    break;

  case Interpreter::accessor:
    entry_point = ((InterpreterGenerator*) this)->generate_accessor_entry();
    break;

  case Interpreter::abstract:
    entry_point = ((InterpreterGenerator*) this)->generate_abstract_entry();
    break;

  case Interpreter::method_handle:
    entry_point = ((InterpreterGenerator*) this)->generate_method_handle_entry();
    break;

  case Interpreter::java_lang_math_sin:
  case Interpreter::java_lang_math_cos:
  case Interpreter::java_lang_math_tan:
  case Interpreter::java_lang_math_abs:
  case Interpreter::java_lang_math_log:
  case Interpreter::java_lang_math_log10:
  case Interpreter::java_lang_math_sqrt:
    entry_point = ((InterpreterGenerator*) this)->generate_math_entry(kind);
    break;

  case Interpreter::java_lang_ref_reference_get:
    entry_point = ((InterpreterGenerator*)this)->generate_Reference_get_entry();
    break;

  default:
    ShouldNotReachHere();
  }

  if (entry_point == NULL)
    entry_point = ((InterpreterGenerator*) this)->generate_normal_entry(false);

  return entry_point;
}

InterpreterGenerator::InterpreterGenerator(StubQueue* code)
 : CppInterpreterGenerator(code) {
   generate_all();
}

// Deoptimization helpers

InterpreterFrame *InterpreterFrame::build(int size, TRAPS) {
  ZeroStack *stack = ((JavaThread *) THREAD)->zero_stack();

  int size_in_words = size >> LogBytesPerWord;
  assert(size_in_words * wordSize == size, "unaligned");
  assert(size_in_words >= header_words, "too small");
  stack->overflow_check(size_in_words, CHECK_NULL);

  stack->push(0); // next_frame, filled in later
  intptr_t *fp = stack->sp();
  assert(fp - stack->sp() == next_frame_off, "should be");

  stack->push(INTERPRETER_FRAME);
  assert(fp - stack->sp() == frame_type_off, "should be");

  interpreterState istate =
    (interpreterState) stack->alloc(sizeof(BytecodeInterpreter));
  assert(fp - stack->sp() == istate_off, "should be");
  istate->set_self_link(NULL); // mark invalid

  stack->alloc((size_in_words - header_words) * wordSize);

  return (InterpreterFrame *) fp;
}

int AbstractInterpreter::layout_activation(methodOop method,
                                           int       tempcount,
                                           int       popframe_extra_args,
                                           int       moncount,
                                           int       callee_param_count,
                                           int       callee_locals,
                                           frame*    caller,
                                           frame*    interpreter_frame,
                                           bool      is_top_frame) {
  assert(popframe_extra_args == 0, "what to do?");
  assert(!is_top_frame || (!callee_locals && !callee_param_count),
         "top frame should have no caller");

  // This code must exactly match what InterpreterFrame::build
  // does (the full InterpreterFrame::build, that is, not the
  // one that creates empty frames for the deoptimizer).
  //
  // If interpreter_frame is not NULL then it will be filled in.
  // It's size is determined by a previous call to this method,
  // so it should be correct.
  //
  // Note that tempcount is the current size of the expression
  // stack.  For top most frames we will allocate a full sized
  // expression stack and not the trimmed version that non-top
  // frames have.

  int header_words        = InterpreterFrame::header_words;
  int monitor_words       = moncount * frame::interpreter_frame_monitor_size();
  int stack_words         = is_top_frame ? method->max_stack() : tempcount;
  int callee_extra_locals = callee_locals - callee_param_count;

  if (interpreter_frame) {
    intptr_t *locals        = interpreter_frame->fp() + method->max_locals();
    interpreterState istate = interpreter_frame->get_interpreterState();
    intptr_t *monitor_base  = (intptr_t*) istate;
    intptr_t *stack_base    = monitor_base - monitor_words;
    intptr_t *stack         = stack_base - tempcount - 1;

    BytecodeInterpreter::layout_interpreterState(istate,
                                                 caller,
                                                 NULL,
                                                 method,
                                                 locals,
                                                 stack,
                                                 stack_base,
                                                 monitor_base,
                                                 NULL,
                                                 is_top_frame);
  }
  return header_words + monitor_words + stack_words + callee_extra_locals;
}

void BytecodeInterpreter::layout_interpreterState(interpreterState istate,
                                                  frame*    caller,
                                                  frame*    current,
                                                  methodOop method,
                                                  intptr_t* locals,
                                                  intptr_t* stack,
                                                  intptr_t* stack_base,
                                                  intptr_t* monitor_base,
                                                  intptr_t* frame_bottom,
                                                  bool      is_top_frame) {
  istate->set_locals(locals);
  istate->set_method(method);
  istate->set_self_link(istate);
  istate->set_prev_link(NULL);
  // thread will be set by a hacky repurposing of frame::patch_pc()
  // bcp will be set by vframeArrayElement::unpack_on_stack()
  istate->set_constants(method->constants()->cache());
  istate->set_msg(BytecodeInterpreter::method_resume);
  istate->set_bcp_advance(0);
  istate->set_oop_temp(NULL);
  istate->set_mdx(NULL);
  if (caller->is_interpreted_frame()) {
    interpreterState prev = caller->get_interpreterState();
    prev->set_callee(method);
    if (*prev->bcp() == Bytecodes::_invokeinterface)
      prev->set_bcp_advance(5);
    else
      prev->set_bcp_advance(3);
  }
  istate->set_callee(NULL);
  istate->set_monitor_base((BasicObjectLock *) monitor_base);
  istate->set_stack_base(stack_base);
  istate->set_stack(stack);
  istate->set_stack_limit(stack_base - method->max_stack() - 1);
}

address CppInterpreter::return_entry(TosState state, int length) {
  ShouldNotCallThis();
}

address CppInterpreter::deopt_entry(TosState state, int length) {
  return NULL;
}

// Helper for (runtime) stack overflow checks

int AbstractInterpreter::size_top_interpreter_activation(methodOop method) {
  return 0;
}

// Helper for figuring out if frames are interpreter frames

bool CppInterpreter::contains(address pc) {
#ifdef PRODUCT
  ShouldNotCallThis();
#else
  return false; // make frame::print_value_on work
#endif // !PRODUCT
}

// Result handlers and convertors

address CppInterpreterGenerator::generate_result_handler_for(
    BasicType type) {
  assembler()->advance(1);
  return ShouldNotCallThisStub();
}

address CppInterpreterGenerator::generate_tosca_to_stack_converter(
    BasicType type) {
  assembler()->advance(1);
  return ShouldNotCallThisStub();
}

address CppInterpreterGenerator::generate_stack_to_stack_converter(
    BasicType type) {
  assembler()->advance(1);
  return ShouldNotCallThisStub();
}

address CppInterpreterGenerator::generate_stack_to_native_abi_converter(
    BasicType type) {
  assembler()->advance(1);
  return ShouldNotCallThisStub();
}

#endif // CC_INTERP