templateInterpreter_x86_64.cpp

/*
 * 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 "asm/assembler.hpp"
#include "interpreter/bytecodeHistogram.hpp"
#include "interpreter/interpreter.hpp"
#include "interpreter/interpreterGenerator.hpp"
#include "interpreter/interpreterRuntime.hpp"
#include "interpreter/templateTable.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/sharedRuntime.hpp"
#include "runtime/stubRoutines.hpp"
#include "runtime/synchronizer.hpp"
#include "runtime/timer.hpp"
#include "runtime/vframeArray.hpp"
#include "utilities/debug.hpp"

#define __ _masm->

#ifndef CC_INTERP

const int method_offset = frame::interpreter_frame_method_offset * wordSize;
const int bci_offset    = frame::interpreter_frame_bcx_offset    * wordSize;
const int locals_offset = frame::interpreter_frame_locals_offset * wordSize;

//-----------------------------------------------------------------------------

address TemplateInterpreterGenerator::generate_StackOverflowError_handler() {
  address entry = __ pc();

#ifdef ASSERT
  {
    Label L;
    __ lea(rax, Address(rbp,
                        frame::interpreter_frame_monitor_block_top_offset *
                        wordSize));
    __ cmpptr(rax, rsp); // rax = maximal rsp for current rbp (stack
                         // grows negative)
    __ jcc(Assembler::aboveEqual, L); // check if frame is complete
    __ stop ("interpreter frame not set up");
    __ bind(L);
  }
#endif // ASSERT
  // Restore bcp under the assumption that the current frame is still
  // interpreted
  __ restore_bcp();

  // expression stack must be empty before entering the VM if an
  // exception happened
  __ empty_expression_stack();
  // throw exception
  __ call_VM(noreg,
             CAST_FROM_FN_PTR(address,
                              InterpreterRuntime::throw_StackOverflowError));
  return entry;
}

address TemplateInterpreterGenerator::generate_ArrayIndexOutOfBounds_handler(
        const char* name) {
  address entry = __ pc();
  // expression stack must be empty before entering the VM if an
  // exception happened
  __ empty_expression_stack();
  // setup parameters
  // ??? convention: expect aberrant index in register ebx
  __ lea(c_rarg1, ExternalAddress((address)name));
  __ call_VM(noreg,
             CAST_FROM_FN_PTR(address,
                              InterpreterRuntime::
                              throw_ArrayIndexOutOfBoundsException),
             c_rarg1, rbx);
  return entry;
}

address TemplateInterpreterGenerator::generate_ClassCastException_handler() {
  address entry = __ pc();

  // object is at TOS
  __ pop(c_rarg1);

  // expression stack must be empty before entering the VM if an
  // exception happened
  __ empty_expression_stack();

  __ call_VM(noreg,
             CAST_FROM_FN_PTR(address,
                              InterpreterRuntime::
                              throw_ClassCastException),
             c_rarg1);
  return entry;
}

// Arguments are: required type at TOS+8, failing object (or NULL) at TOS+4.
address TemplateInterpreterGenerator::generate_WrongMethodType_handler() {
  address entry = __ pc();

  __ pop(c_rarg2);              // failing object is at TOS
  __ pop(c_rarg1);              // required type is at TOS+8

  __ verify_oop(c_rarg1);
  __ verify_oop(c_rarg2);

  // Various method handle types use interpreter registers as temps.
  __ restore_bcp();
  __ restore_locals();

  // Expression stack must be empty before entering the VM for an exception.
  __ empty_expression_stack();

  __ call_VM(noreg,
             CAST_FROM_FN_PTR(address,
                              InterpreterRuntime::throw_WrongMethodTypeException),
             // pass required type, failing object (or NULL)
             c_rarg1, c_rarg2);
  return entry;
}

address TemplateInterpreterGenerator::generate_exception_handler_common(
        const char* name, const char* message, bool pass_oop) {
  assert(!pass_oop || message == NULL, "either oop or message but not both");
  address entry = __ pc();
  if (pass_oop) {
    // object is at TOS
    __ pop(c_rarg2);
  }
  // expression stack must be empty before entering the VM if an
  // exception happened
  __ empty_expression_stack();
  // setup parameters
  __ lea(c_rarg1, ExternalAddress((address)name));
  if (pass_oop) {
    __ call_VM(rax, CAST_FROM_FN_PTR(address,
                                     InterpreterRuntime::
                                     create_klass_exception),
               c_rarg1, c_rarg2);
  } else {
    // kind of lame ExternalAddress can't take NULL because
    // external_word_Relocation will assert.
    if (message != NULL) {
      __ lea(c_rarg2, ExternalAddress((address)message));
    } else {
      __ movptr(c_rarg2, NULL_WORD);
    }
    __ call_VM(rax,
               CAST_FROM_FN_PTR(address, InterpreterRuntime::create_exception),
               c_rarg1, c_rarg2);
  }
  // throw exception
  __ jump(ExternalAddress(Interpreter::throw_exception_entry()));
  return entry;
}


address TemplateInterpreterGenerator::generate_continuation_for(TosState state) {
  address entry = __ pc();
  // NULL last_sp until next java call
  __ movptr(Address(rbp, frame::interpreter_frame_last_sp_offset * wordSize), (int32_t)NULL_WORD);
  __ dispatch_next(state);
  return entry;
}


address TemplateInterpreterGenerator::generate_return_entry_for(TosState state, int step) {
  address entry = __ pc();

  // Restore stack bottom in case i2c adjusted stack
  __ movptr(rsp, Address(rbp, frame::interpreter_frame_last_sp_offset * wordSize));
  // and NULL it as marker that esp is now tos until next java call
  __ movptr(Address(rbp, frame::interpreter_frame_last_sp_offset * wordSize), (int32_t)NULL_WORD);

  __ restore_bcp();
  __ restore_locals();

  Label L_got_cache, L_giant_index;
  if (EnableInvokeDynamic) {
    __ cmpb(Address(r13, 0), Bytecodes::_invokedynamic);
    __ jcc(Assembler::equal, L_giant_index);
  }
  __ get_cache_and_index_at_bcp(rbx, rcx, 1, sizeof(u2));
  __ bind(L_got_cache);
  __ movl(rbx, Address(rbx, rcx,
                       Address::times_ptr,
                       in_bytes(constantPoolCacheOopDesc::base_offset()) +
                       3 * wordSize));
  __ andl(rbx, 0xFF);
  __ lea(rsp, Address(rsp, rbx, Address::times_8));
  __ dispatch_next(state, step);

  // out of the main line of code...
  if (EnableInvokeDynamic) {
    __ bind(L_giant_index);
    __ get_cache_and_index_at_bcp(rbx, rcx, 1, sizeof(u4));
    __ jmp(L_got_cache);
  }

  return entry;
}


address TemplateInterpreterGenerator::generate_deopt_entry_for(TosState state,
                                                               int step) {
  address entry = __ pc();
  // NULL last_sp until next java call
  __ movptr(Address(rbp, frame::interpreter_frame_last_sp_offset * wordSize), (int32_t)NULL_WORD);
  __ restore_bcp();
  __ restore_locals();
  // handle exceptions
  {
    Label L;
    __ cmpptr(Address(r15_thread, Thread::pending_exception_offset()), (int32_t) NULL_WORD);
    __ jcc(Assembler::zero, L);
    __ call_VM(noreg,
               CAST_FROM_FN_PTR(address,
                                InterpreterRuntime::throw_pending_exception));
    __ should_not_reach_here();
    __ bind(L);
  }
  __ dispatch_next(state, step);
  return entry;
}

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;
}


address TemplateInterpreterGenerator::generate_result_handler_for(
        BasicType type) {
  address entry = __ pc();
  switch (type) {
  case T_BOOLEAN: __ c2bool(rax);            break;
  case T_CHAR   : __ movzwl(rax, rax);       break;
  case T_BYTE   : __ sign_extend_byte(rax);  break;
  case T_SHORT  : __ sign_extend_short(rax); break;
  case T_INT    : /* nothing to do */        break;
  case T_LONG   : /* nothing to do */        break;
  case T_VOID   : /* nothing to do */        break;
  case T_FLOAT  : /* nothing to do */        break;
  case T_DOUBLE : /* nothing to do */        break;
  case T_OBJECT :
    // retrieve result from frame
    __ movptr(rax, Address(rbp, frame::interpreter_frame_oop_temp_offset*wordSize));
    // and verify it
    __ verify_oop(rax);
    break;
  default       : ShouldNotReachHere();
  }
  __ ret(0);                                   // return from result handler
  return entry;
}

address TemplateInterpreterGenerator::generate_safept_entry_for(
        TosState state,
        address runtime_entry) {
  address entry = __ pc();
  __ push(state);
  __ call_VM(noreg, runtime_entry);
  __ dispatch_via(vtos, Interpreter::_normal_table.table_for(vtos));
  return entry;
}



// Helpers for commoning out cases in the various type of method entries.
//


// increment invocation count & check for overflow
//
// Note: checking for negative value instead of overflow
//       so we have a 'sticky' overflow test
//
// rbx: method
// ecx: invocation counter
//
void InterpreterGenerator::generate_counter_incr(
        Label* overflow,
        Label* profile_method,
        Label* profile_method_continue) {
  const Address invocation_counter(rbx, in_bytes(methodOopDesc::invocation_counter_offset()) +
                                        in_bytes(InvocationCounter::counter_offset()));
  // Note: In tiered we increment either counters in methodOop or in MDO depending if we're profiling or not.
  if (TieredCompilation) {
    int increment = InvocationCounter::count_increment;
    int mask = ((1 << Tier0InvokeNotifyFreqLog)  - 1) << InvocationCounter::count_shift;
    Label no_mdo, done;
    if (ProfileInterpreter) {
      // Are we profiling?
      __ movptr(rax, Address(rbx, methodOopDesc::method_data_offset()));
      __ testptr(rax, rax);
      __ jccb(Assembler::zero, no_mdo);
      // Increment counter in the MDO
      const Address mdo_invocation_counter(rax, in_bytes(methodDataOopDesc::invocation_counter_offset()) +
                                                in_bytes(InvocationCounter::counter_offset()));
      __ increment_mask_and_jump(mdo_invocation_counter, increment, mask, rcx, false, Assembler::zero, overflow);
      __ jmpb(done);
    }
    __ bind(no_mdo);
    // Increment counter in methodOop (we don't need to load it, it's in ecx).
    __ increment_mask_and_jump(invocation_counter, increment, mask, rcx, true, Assembler::zero, overflow);
    __ bind(done);
  } else {
    const Address backedge_counter(rbx,
                                   methodOopDesc::backedge_counter_offset() +
                                   InvocationCounter::counter_offset());

    if (ProfileInterpreter) { // %%% Merge this into methodDataOop
      __ incrementl(Address(rbx,
                            methodOopDesc::interpreter_invocation_counter_offset()));
    }
    // Update standard invocation counters
    __ movl(rax, backedge_counter);   // load backedge counter

    __ incrementl(rcx, InvocationCounter::count_increment);
    __ andl(rax, InvocationCounter::count_mask_value); // mask out the status bits

    __ movl(invocation_counter, rcx); // save invocation count
    __ addl(rcx, rax);                // add both counters

    // profile_method is non-null only for interpreted method so
    // profile_method != NULL == !native_call

    if (ProfileInterpreter && profile_method != NULL) {
      // Test to see if we should create a method data oop
      __ cmp32(rcx, ExternalAddress((address)&InvocationCounter::InterpreterProfileLimit));
      __ jcc(Assembler::less, *profile_method_continue);

      // if no method data exists, go to profile_method
      __ test_method_data_pointer(rax, *profile_method);
    }

    __ cmp32(rcx, ExternalAddress((address)&InvocationCounter::InterpreterInvocationLimit));
    __ jcc(Assembler::aboveEqual, *overflow);
  }
}

void InterpreterGenerator::generate_counter_overflow(Label* do_continue) {

  // Asm interpreter on entry
  // r14 - locals
  // r13 - bcp
  // rbx - method
  // edx - cpool --- DOES NOT APPEAR TO BE TRUE
  // rbp - interpreter frame

  // On return (i.e. jump to entry_point) [ back to invocation of interpreter ]
  // Everything as it was on entry
  // rdx is not restored. Doesn't appear to really be set.

  const Address size_of_parameters(rbx,
                                   methodOopDesc::size_of_parameters_offset());

  // InterpreterRuntime::frequency_counter_overflow takes two
  // arguments, the first (thread) is passed by call_VM, the second
  // indicates if the counter overflow occurs at a backwards branch
  // (NULL bcp).  We pass zero for it.  The call returns the address
  // of the verified entry point for the method or NULL if the
  // compilation did not complete (either went background or bailed
  // out).
  __ movl(c_rarg1, 0);
  __ call_VM(noreg,
             CAST_FROM_FN_PTR(address,
                              InterpreterRuntime::frequency_counter_overflow),
             c_rarg1);

  __ movptr(rbx, Address(rbp, method_offset));   // restore methodOop
  // Preserve invariant that r13/r14 contain bcp/locals of sender frame
  // and jump to the interpreted entry.
  __ jmp(*do_continue, relocInfo::none);
}

// See if we've got enough room on the stack for locals plus overhead.
// The expression stack grows down incrementally, so the normal guard
// page mechanism will work for that.
//
// NOTE: Since the additional locals are also always pushed (wasn't
// obvious in generate_method_entry) so the guard should work for them
// too.
//
// Args:
//      rdx: number of additional locals this frame needs (what we must check)
//      rbx: methodOop
//
// Kills:
//      rax
void InterpreterGenerator::generate_stack_overflow_check(void) {

  // monitor entry size: see picture of stack set
  // (generate_method_entry) and frame_amd64.hpp
  const int entry_size = frame::interpreter_frame_monitor_size() * wordSize;

  // total overhead size: entry_size + (saved rbp through expr stack
  // bottom).  be sure to change this if you add/subtract anything
  // to/from the overhead area
  const int overhead_size =
    -(frame::interpreter_frame_initial_sp_offset * wordSize) + entry_size;

  const int page_size = os::vm_page_size();

  Label after_frame_check;

  // see if the frame is greater than one page in size. If so,
  // then we need to verify there is enough stack space remaining
  // for the additional locals.
  __ cmpl(rdx, (page_size - overhead_size) / Interpreter::stackElementSize);
  __ jcc(Assembler::belowEqual, after_frame_check);

  // compute rsp as if this were going to be the last frame on
  // the stack before the red zone

  const Address stack_base(r15_thread, Thread::stack_base_offset());
  const Address stack_size(r15_thread, Thread::stack_size_offset());

  // locals + overhead, in bytes
  __ mov(rax, rdx);
  __ shlptr(rax, Interpreter::logStackElementSize);  // 2 slots per parameter.
  __ addptr(rax, overhead_size);

#ifdef ASSERT
  Label stack_base_okay, stack_size_okay;
  // verify that thread stack base is non-zero
  __ cmpptr(stack_base, (int32_t)NULL_WORD);
  __ jcc(Assembler::notEqual, stack_base_okay);
  __ stop("stack base is zero");
  __ bind(stack_base_okay);
  // verify that thread stack size is non-zero
  __ cmpptr(stack_size, 0);
  __ jcc(Assembler::notEqual, stack_size_okay);
  __ stop("stack size is zero");
  __ bind(stack_size_okay);
#endif

  // Add stack base to locals and subtract stack size
  __ addptr(rax, stack_base);
  __ subptr(rax, stack_size);

  // Use the maximum number of pages we might bang.
  const int max_pages = StackShadowPages > (StackRedPages+StackYellowPages) ? StackShadowPages :
                                                                              (StackRedPages+StackYellowPages);

  // add in the red and yellow zone sizes
  __ addptr(rax, max_pages * page_size);

  // check against the current stack bottom
  __ cmpptr(rsp, rax);
  __ jcc(Assembler::above, after_frame_check);

  __ pop(rax); // get return address
  __ jump(ExternalAddress(Interpreter::throw_StackOverflowError_entry()));

  // all done with frame size check
  __ bind(after_frame_check);
}

// Allocate monitor and lock method (asm interpreter)
//
// Args:
//      rbx: methodOop
//      r14: locals
//
// Kills:
//      rax
//      c_rarg0, c_rarg1, c_rarg2, c_rarg3, ...(param regs)
//      rscratch1, rscratch2 (scratch regs)
void InterpreterGenerator::lock_method(void) {
  // synchronize method
  const Address access_flags(rbx, methodOopDesc::access_flags_offset());
  const Address monitor_block_top(
        rbp,
        frame::interpreter_frame_monitor_block_top_offset * wordSize);
  const int entry_size = frame::interpreter_frame_monitor_size() * wordSize;

#ifdef ASSERT
  {
    Label L;
    __ movl(rax, access_flags);
    __ testl(rax, JVM_ACC_SYNCHRONIZED);
    __ jcc(Assembler::notZero, L);
    __ stop("method doesn't need synchronization");
    __ bind(L);
  }
#endif // ASSERT

  // get synchronization object
  {
    const int mirror_offset = klassOopDesc::klass_part_offset_in_bytes() +
                              Klass::java_mirror_offset_in_bytes();
    Label done;
    __ movl(rax, access_flags);
    __ testl(rax, JVM_ACC_STATIC);
    // get receiver (assume this is frequent case)
    __ movptr(rax, Address(r14, Interpreter::local_offset_in_bytes(0)));
    __ jcc(Assembler::zero, done);
    __ movptr(rax, Address(rbx, methodOopDesc::constants_offset()));
    __ movptr(rax, Address(rax,
                           constantPoolOopDesc::pool_holder_offset_in_bytes()));
    __ movptr(rax, Address(rax, mirror_offset));

#ifdef ASSERT
    {
      Label L;
      __ testptr(rax, rax);
      __ jcc(Assembler::notZero, L);
      __ stop("synchronization object is NULL");
      __ bind(L);
    }
#endif // ASSERT

    __ bind(done);
  }

  // add space for monitor & lock
  __ subptr(rsp, entry_size); // add space for a monitor entry
  __ movptr(monitor_block_top, rsp);  // set new monitor block top
  // store object
  __ movptr(Address(rsp, BasicObjectLock::obj_offset_in_bytes()), rax);
  __ movptr(c_rarg1, rsp); // object address
  __ lock_object(c_rarg1);
}

// Generate a fixed interpreter frame. This is identical setup for
// interpreted methods and for native methods hence the shared code.
//
// Args:
//      rax: return address
//      rbx: methodOop
//      r14: pointer to locals
//      r13: sender sp
//      rdx: cp cache
void TemplateInterpreterGenerator::generate_fixed_frame(bool native_call) {
  // initialize fixed part of activation frame
  __ push(rax);        // save return address
  __ enter();          // save old & set new rbp
  __ push(r13);        // set sender sp
  __ push((int)NULL_WORD); // leave last_sp as null
  __ movptr(r13, Address(rbx, methodOopDesc::const_offset()));      // get constMethodOop
  __ lea(r13, Address(r13, constMethodOopDesc::codes_offset())); // get codebase
  __ push(rbx);        // save methodOop
  if (ProfileInterpreter) {
    Label method_data_continue;
    __ movptr(rdx, Address(rbx, in_bytes(methodOopDesc::method_data_offset())));
    __ testptr(rdx, rdx);
    __ jcc(Assembler::zero, method_data_continue);
    __ addptr(rdx, in_bytes(methodDataOopDesc::data_offset()));
    __ bind(method_data_continue);
    __ push(rdx);      // set the mdp (method data pointer)
  } else {
    __ push(0);
  }

  __ movptr(rdx, Address(rbx, methodOopDesc::constants_offset()));
  __ movptr(rdx, Address(rdx, constantPoolOopDesc::cache_offset_in_bytes()));
  __ push(rdx); // set constant pool cache
  __ push(r14); // set locals pointer
  if (native_call) {
    __ push(0); // no bcp
  } else {
    __ push(r13); // set bcp
  }
  __ push(0); // reserve word for pointer to expression stack bottom
  __ movptr(Address(rsp, 0), rsp); // set expression stack bottom
}

// End of helpers

// Various method entries
//------------------------------------------------------------------------------------------------------------------------
//
//

// Call an accessor method (assuming it is resolved, otherwise drop
// into vanilla (slow path) entry
address InterpreterGenerator::generate_accessor_entry(void) {
  // rbx: methodOop

  // r13: senderSP must preserver for slow path, set SP to it on fast path

  address entry_point = __ pc();
  Label xreturn_path;

  // do fastpath for resolved accessor methods
  if (UseFastAccessorMethods) {
    // Code: _aload_0, _(i|a)getfield, _(i|a)return or any rewrites
    //       thereof; parameter size = 1
    // Note: We can only use this code if the getfield has been resolved
    //       and if we don't have a null-pointer exception => check for
    //       these conditions first and use slow path if necessary.
    Label slow_path;
    // If we need a safepoint check, generate full interpreter entry.
    __ cmp32(ExternalAddress(SafepointSynchronize::address_of_state()),
             SafepointSynchronize::_not_synchronized);

    __ jcc(Assembler::notEqual, slow_path);
    // rbx: method
    __ movptr(rax, Address(rsp, wordSize));

    // check if local 0 != NULL and read field
    __ testptr(rax, rax);
    __ jcc(Assembler::zero, slow_path);

    __ movptr(rdi, Address(rbx, methodOopDesc::constants_offset()));
    // read first instruction word and extract bytecode @ 1 and index @ 2
    __ movptr(rdx, Address(rbx, methodOopDesc::const_offset()));
    __ movl(rdx, Address(rdx, constMethodOopDesc::codes_offset()));
    // Shift codes right to get the index on the right.
    // The bytecode fetched looks like <index><0xb4><0x2a>
    __ shrl(rdx, 2 * BitsPerByte);
    __ shll(rdx, exact_log2(in_words(ConstantPoolCacheEntry::size())));
    __ movptr(rdi, Address(rdi, constantPoolOopDesc::cache_offset_in_bytes()));

    // rax: local 0
    // rbx: method
    // rdx: constant pool cache index
    // rdi: constant pool cache

    // check if getfield has been resolved and read constant pool cache entry
    // check the validity of the cache entry by testing whether _indices field
    // contains Bytecode::_getfield in b1 byte.
    assert(in_words(ConstantPoolCacheEntry::size()) == 4,
           "adjust shift below");
    __ movl(rcx,
            Address(rdi,
                    rdx,
                    Address::times_8,
                    constantPoolCacheOopDesc::base_offset() +
                    ConstantPoolCacheEntry::indices_offset()));
    __ shrl(rcx, 2 * BitsPerByte);
    __ andl(rcx, 0xFF);
    __ cmpl(rcx, Bytecodes::_getfield);
    __ jcc(Assembler::notEqual, slow_path);

    // Note: constant pool entry is not valid before bytecode is resolved
    __ movptr(rcx,
              Address(rdi,
                      rdx,
                      Address::times_8,
                      constantPoolCacheOopDesc::base_offset() +
                      ConstantPoolCacheEntry::f2_offset()));
    // edx: flags
    __ movl(rdx,
            Address(rdi,
                    rdx,
                    Address::times_8,
                    constantPoolCacheOopDesc::base_offset() +
                    ConstantPoolCacheEntry::flags_offset()));

    Label notObj, notInt, notByte, notShort;
    const Address field_address(rax, rcx, Address::times_1);

    // Need to differentiate between igetfield, agetfield, bgetfield etc.
    // because they are different sizes.
    // Use the type from the constant pool cache
    __ shrl(rdx, ConstantPoolCacheEntry::tosBits);
    // Make sure we don't need to mask edx for tosBits after the above shift
    ConstantPoolCacheEntry::verify_tosBits();

    __ cmpl(rdx, atos);
    __ jcc(Assembler::notEqual, notObj);
    // atos
    __ load_heap_oop(rax, field_address);
    __ jmp(xreturn_path);

    __ bind(notObj);
    __ cmpl(rdx, itos);
    __ jcc(Assembler::notEqual, notInt);
    // itos
    __ movl(rax, field_address);
    __ jmp(xreturn_path);

    __ bind(notInt);
    __ cmpl(rdx, btos);
    __ jcc(Assembler::notEqual, notByte);
    // btos
    __ load_signed_byte(rax, field_address);
    __ jmp(xreturn_path);

    __ bind(notByte);
    __ cmpl(rdx, stos);
    __ jcc(Assembler::notEqual, notShort);
    // stos
    __ load_signed_short(rax, field_address);
    __ jmp(xreturn_path);

    __ bind(notShort);
#ifdef ASSERT
    Label okay;
    __ cmpl(rdx, ctos);
    __ jcc(Assembler::equal, okay);
    __ stop("what type is this?");
    __ bind(okay);
#endif
    // ctos
    __ load_unsigned_short(rax, field_address);

    __ bind(xreturn_path);

    // _ireturn/_areturn
    __ pop(rdi);
    __ mov(rsp, r13);
    __ jmp(rdi);
    __ ret(0);

    // generate a vanilla interpreter entry as the slow path
    __ bind(slow_path);
    (void) generate_normal_entry(false);
  } else {
    (void) generate_normal_entry(false);
  }

  return entry_point;
}

// Method entry for java.lang.ref.Reference.get.
address InterpreterGenerator::generate_Reference_get_entry(void) {
#ifndef SERIALGC
  // Code: _aload_0, _getfield, _areturn
  // parameter size = 1
  //
  // The code that gets generated by this routine is split into 2 parts:
  //    1. The "intrinsified" code for G1 (or any SATB based GC),
  //    2. The slow path - which is an expansion of the regular method entry.
  //
  // Notes:-
  // * In the G1 code we do not check whether we need to block for
  //   a safepoint. If G1 is enabled then we must execute the specialized
  //   code for Reference.get (except when the Reference object is null)
  //   so that we can log the value in the referent field with an SATB
  //   update buffer.
  //   If the code for the getfield template is modified so that the
  //   G1 pre-barrier code is executed when the current method is
  //   Reference.get() then going through the normal method entry
  //   will be fine.
  // * The G1 code can, however, check the receiver object (the instance
  //   of java.lang.Reference) and jump to the slow path if null. If the
  //   Reference object is null then we obviously cannot fetch the referent
  //   and so we don't need to call the G1 pre-barrier. Thus we can use the
  //   regular method entry code to generate the NPE.
  //
  // This code is based on generate_accessor_enty.
  //
  // rbx: methodOop

  // r13: senderSP must preserve for slow path, set SP to it on fast path

  address entry = __ pc();

  const int referent_offset = java_lang_ref_Reference::referent_offset;
  guarantee(referent_offset > 0, "referent offset not initialized");

  if (UseG1GC) {
    Label slow_path;
    // rbx: method

    // Check if local 0 != NULL
    // If the receiver is null then it is OK to jump to the slow path.
    __ movptr(rax, Address(rsp, wordSize));

    __ testptr(rax, rax);
    __ jcc(Assembler::zero, slow_path);

    // rax: local 0
    // rbx: method (but can be used as scratch now)
    // rdx: scratch
    // rdi: scratch

    // Generate the G1 pre-barrier code to log the value of
    // the referent field in an SATB buffer.

    // Load the value of the referent field.
    const Address field_address(rax, referent_offset);
    __ load_heap_oop(rax, field_address);

    // Generate the G1 pre-barrier code to log the value of
    // the referent field in an SATB buffer.
    __ g1_write_barrier_pre(noreg /* obj */,
                            rax /* pre_val */,
                            r15_thread /* thread */,
                            rbx /* tmp */,
                            true /* tosca_live */,
                            true /* expand_call */);

    // _areturn
    __ pop(rdi);                // get return address
    __ mov(rsp, r13);           // set sp to sender sp
    __ jmp(rdi);
    __ ret(0);

    // generate a vanilla interpreter entry as the slow path
    __ bind(slow_path);
    (void) generate_normal_entry(false);

    return entry;
  }
#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();
}


// Interpreter stub for calling a native method. (asm interpreter)
// This sets up a somewhat different looking stack for calling the
// native method than the typical interpreter frame setup.
address InterpreterGenerator::generate_native_entry(bool synchronized) {
  // determine code generation flags
  bool inc_counter  = UseCompiler || CountCompiledCalls;

  // rbx: methodOop
  // r13: sender sp

  address entry_point = __ pc();

  const Address size_of_parameters(rbx, methodOopDesc::
                                        size_of_parameters_offset());
  const Address invocation_counter(rbx, methodOopDesc::
                                        invocation_counter_offset() +
                                        InvocationCounter::counter_offset());
  const Address access_flags      (rbx, methodOopDesc::access_flags_offset());

  // get parameter size (always needed)
  __ load_unsigned_short(rcx, size_of_parameters);

  // native calls don't need the stack size check since they have no
  // expression stack and the arguments are already on the stack and
  // we only add a handful of words to the stack

  // rbx: methodOop
  // rcx: size of parameters
  // r13: sender sp
  __ pop(rax);                                       // get return address

  // for natives the size of locals is zero

  // compute beginning of parameters (r14)
  __ lea(r14, Address(rsp, rcx, Address::times_8, -wordSize));

  // add 2 zero-initialized slots for native calls
  // initialize result_handler slot
  __ push((int) NULL_WORD);
  // slot for oop temp
  // (static native method holder mirror/jni oop result)
  __ push((int) NULL_WORD);

  if (inc_counter) {
    __ movl(rcx, invocation_counter);  // (pre-)fetch invocation count
  }

  // initialize fixed part of activation frame
  generate_fixed_frame(true);

  // make sure method is native & not abstract
#ifdef ASSERT
  __ movl(rax, access_flags);
  {
    Label L;
    __ testl(rax, JVM_ACC_NATIVE);
    __ jcc(Assembler::notZero, L);
    __ stop("tried to execute non-native method as native");
    __ bind(L);
  }
  {
    Label L;
    __ testl(rax, JVM_ACC_ABSTRACT);
    __ jcc(Assembler::zero, L);
    __ stop("tried to execute abstract method in interpreter");
    __ bind(L);
  }
#endif

  // Since at this point in the method invocation the exception handler
  // would try to exit the monitor of synchronized methods which hasn't
  // been entered yet, we set the thread local variable
  // _do_not_unlock_if_synchronized to true. The remove_activation will
  // check this flag.

  const Address do_not_unlock_if_synchronized(r15_thread,
        in_bytes(JavaThread::do_not_unlock_if_synchronized_offset()));
  __ movbool(do_not_unlock_if_synchronized, true);

  // increment invocation count & check for overflow
  Label invocation_counter_overflow;
  if (inc_counter) {
    generate_counter_incr(&invocation_counter_overflow, NULL, NULL);
  }

  Label continue_after_compile;
  __ bind(continue_after_compile);

  bang_stack_shadow_pages(true);

  // reset the _do_not_unlock_if_synchronized flag
  __ movbool(do_not_unlock_if_synchronized, false);

  // check for synchronized methods
  // Must happen AFTER invocation_counter check and stack overflow check,
  // so method is not locked if overflows.
  if (synchronized) {
    lock_method();
  } else {
    // no synchronization necessary
#ifdef ASSERT
    {
      Label L;
      __ movl(rax, access_flags);
      __ testl(rax, JVM_ACC_SYNCHRONIZED);
      __ jcc(Assembler::zero, L);
      __ stop("method needs synchronization");
      __ bind(L);
    }
#endif
  }

  // start execution
#ifdef ASSERT
  {
    Label L;
    const Address monitor_block_top(rbp,
                 frame::interpreter_frame_monitor_block_top_offset * wordSize);
    __ movptr(rax, monitor_block_top);
    __ cmpptr(rax, rsp);
    __ jcc(Assembler::equal, L);
    __ stop("broken stack frame setup in interpreter");
    __ bind(L);
  }
#endif

  // jvmti support
  __ notify_method_entry();

  // work registers
  const Register method = rbx;
  const Register t      = r11;

  // allocate space for parameters
  __ get_method(method);
  __ verify_oop(method);
  __ load_unsigned_short(t,
                         Address(method,
                                 methodOopDesc::size_of_parameters_offset()));
  __ shll(t, Interpreter::logStackElementSize);

  __ subptr(rsp, t);
  __ subptr(rsp, frame::arg_reg_save_area_bytes); // windows
  __ andptr(rsp, -16); // must be 16 byte boundary (see amd64 ABI)

  // get signature handler
  {
    Label L;
    __ movptr(t, Address(method, methodOopDesc::signature_handler_offset()));
    __ testptr(t, t);
    __ jcc(Assembler::notZero, L);
    __ call_VM(noreg,
               CAST_FROM_FN_PTR(address,
                                InterpreterRuntime::prepare_native_call),
               method);
    __ get_method(method);
    __ movptr(t, Address(method, methodOopDesc::signature_handler_offset()));
    __ bind(L);
  }

  // call signature handler
  assert(InterpreterRuntime::SignatureHandlerGenerator::from() == r14,
         "adjust this code");
  assert(InterpreterRuntime::SignatureHandlerGenerator::to() == rsp,
         "adjust this code");
  assert(InterpreterRuntime::SignatureHandlerGenerator::temp() == rscratch1,
          "adjust this code");

  // The generated handlers do not touch RBX (the method oop).
  // However, large signatures cannot be cached and are generated
  // each time here.  The slow-path generator can do a GC on return,
  // so we must reload it after the call.
  __ call(t);
  __ get_method(method);        // slow path can do a GC, reload RBX


  // result handler is in rax
  // set result handler
  __ movptr(Address(rbp,
                    (frame::interpreter_frame_result_handler_offset) * wordSize),
            rax);

  // pass mirror handle if static call
  {
    Label L;
    const int mirror_offset = klassOopDesc::klass_part_offset_in_bytes() +
                              Klass::java_mirror_offset_in_bytes();
    __ movl(t, Address(method, methodOopDesc::access_flags_offset()));
    __ testl(t, JVM_ACC_STATIC);
    __ jcc(Assembler::zero, L);
    // get mirror
    __ movptr(t, Address(method, methodOopDesc::constants_offset()));
    __ movptr(t, Address(t, constantPoolOopDesc::pool_holder_offset_in_bytes()));
    __ movptr(t, Address(t, mirror_offset));
    // copy mirror into activation frame
    __ movptr(Address(rbp, frame::interpreter_frame_oop_temp_offset * wordSize),
            t);
    // pass handle to mirror
    __ lea(c_rarg1,
           Address(rbp, frame::interpreter_frame_oop_temp_offset * wordSize));
    __ bind(L);
  }

  // get native function entry point
  {
    Label L;
    __ movptr(rax, Address(method, methodOopDesc::native_function_offset()));
    ExternalAddress unsatisfied(SharedRuntime::native_method_throw_unsatisfied_link_error_entry());
    __ movptr(rscratch2, unsatisfied.addr());
    __ cmpptr(rax, rscratch2);
    __ jcc(Assembler::notEqual, L);
    __ call_VM(noreg,
               CAST_FROM_FN_PTR(address,
                                InterpreterRuntime::prepare_native_call),
               method);
    __ get_method(method);
    __ verify_oop(method);
    __ movptr(rax, Address(method, methodOopDesc::native_function_offset()));
    __ bind(L);
  }

  // pass JNIEnv
  __ lea(c_rarg0, Address(r15_thread, JavaThread::jni_environment_offset()));

  // It is enough that the pc() points into the right code
  // segment. It does not have to be the correct return pc.
  __ set_last_Java_frame(rsp, rbp, (address) __ pc());

  // change thread state
#ifdef ASSERT
  {
    Label L;
    __ movl(t, Address(r15_thread, JavaThread::thread_state_offset()));
    __ cmpl(t, _thread_in_Java);
    __ jcc(Assembler::equal, L);
    __ stop("Wrong thread state in native stub");
    __ bind(L);
  }
#endif

  // Change state to native

  __ movl(Address(r15_thread, JavaThread::thread_state_offset()),
          _thread_in_native);

  // Call the native method.
  __ call(rax);
  // result potentially in rax or xmm0

  // Depending on runtime options, either restore the MXCSR
  // register after returning from the JNI Call or verify that
  // it wasn't changed during -Xcheck:jni.
  if (RestoreMXCSROnJNICalls) {
    __ ldmxcsr(ExternalAddress(StubRoutines::x86::mxcsr_std()));
  }
  else if (CheckJNICalls) {
    __ call(RuntimeAddress(CAST_FROM_FN_PTR(address, StubRoutines::x86::verify_mxcsr_entry())));
  }

  // NOTE: The order of these pushes is known to frame::interpreter_frame_result
  // in order to extract the result of a method call. If the order of these
  // pushes change or anything else is added to the stack then the code in
  // interpreter_frame_result must also change.

  __ push(dtos);
  __ push(ltos);

  // change thread state
  __ movl(Address(r15_thread, JavaThread::thread_state_offset()),
          _thread_in_native_trans);

  if (os::is_MP()) {
    if (UseMembar) {
      // Force this write out before the read below
      __ membar(Assembler::Membar_mask_bits(
           Assembler::LoadLoad | Assembler::LoadStore |
           Assembler::StoreLoad | Assembler::StoreStore));
    } else {
      // Write serialization page so VM thread can do a pseudo remote membar.
      // We use the current thread pointer to calculate a thread specific
      // offset to write to within the page. This minimizes bus traffic
      // due to cache line collision.
      __ serialize_memory(r15_thread, rscratch2);
    }
  }

  // check for safepoint operation in progress and/or pending suspend requests
  {
    Label Continue;
    __ cmp32(ExternalAddress(SafepointSynchronize::address_of_state()),
             SafepointSynchronize::_not_synchronized);

    Label L;
    __ jcc(Assembler::notEqual, L);
    __ cmpl(Address(r15_thread, JavaThread::suspend_flags_offset()), 0);
    __ jcc(Assembler::equal, Continue);
    __ bind(L);

    // Don't use call_VM as it will see a possible pending exception
    // and forward it and never return here preventing us from
    // clearing _last_native_pc down below.  Also can't use
    // call_VM_leaf either as it will check to see if r13 & r14 are
    // preserved and correspond to the bcp/locals pointers. So we do a
    // runtime call by hand.
    //
    __ mov(c_rarg0, r15_thread);
    __ mov(r12, rsp); // remember sp (can only use r12 if not using call_VM)
    __ subptr(rsp, frame::arg_reg_save_area_bytes); // windows
    __ andptr(rsp, -16); // align stack as required by ABI
    __ call(RuntimeAddress(CAST_FROM_FN_PTR(address, JavaThread::check_special_condition_for_native_trans)));
    __ mov(rsp, r12); // restore sp
    __ reinit_heapbase();
    __ bind(Continue);
  }

  // change thread state
  __ movl(Address(r15_thread, JavaThread::thread_state_offset()), _thread_in_Java);

  // reset_last_Java_frame
  __ reset_last_Java_frame(true, true);

  // reset handle block
  __ movptr(t, Address(r15_thread, JavaThread::active_handles_offset()));
  __ movptr(Address(t, JNIHandleBlock::top_offset_in_bytes()), (int32_t)NULL_WORD);

  // If result is an oop unbox and store it in frame where gc will see it
  // and result handler will pick it up

  {
    Label no_oop, store_result;
    __ lea(t, ExternalAddress(AbstractInterpreter::result_handler(T_OBJECT)));
    __ cmpptr(t, Address(rbp, frame::interpreter_frame_result_handler_offset*wordSize));
    __ jcc(Assembler::notEqual, no_oop);
    // retrieve result
    __ pop(ltos);
    __ testptr(rax, rax);
    __ jcc(Assembler::zero, store_result);
    __ movptr(rax, Address(rax, 0));
    __ bind(store_result);
    __ movptr(Address(rbp, frame::interpreter_frame_oop_temp_offset*wordSize), rax);
    // keep stack depth as expected by pushing oop which will eventually be discarde
    __ push(ltos);
    __ bind(no_oop);
  }


  {
    Label no_reguard;
    __ cmpl(Address(r15_thread, JavaThread::stack_guard_state_offset()),
            JavaThread::stack_guard_yellow_disabled);
    __ jcc(Assembler::notEqual, no_reguard);

    __ pusha(); // XXX only save smashed registers
    __ mov(r12, rsp); // remember sp (can only use r12 if not using call_VM)
    __ subptr(rsp, frame::arg_reg_save_area_bytes); // windows
    __ andptr(rsp, -16); // align stack as required by ABI
    __ call(RuntimeAddress(CAST_FROM_FN_PTR(address, SharedRuntime::reguard_yellow_pages)));
    __ mov(rsp, r12); // restore sp
    __ popa(); // XXX only restore smashed registers
    __ reinit_heapbase();

    __ bind(no_reguard);
  }


  // The method register is junk from after the thread_in_native transition
  // until here.  Also can't call_VM until the bcp has been
  // restored.  Need bcp for throwing exception below so get it now.
  __ get_method(method);
  __ verify_oop(method);

  // restore r13 to have legal interpreter frame, i.e., bci == 0 <=>
  // r13 == code_base()
  __ movptr(r13, Address(method, methodOopDesc::const_offset()));   // get constMethodOop
  __ lea(r13, Address(r13, constMethodOopDesc::codes_offset()));    // get codebase
  // handle exceptions (exception handling will handle unlocking!)
  {
    Label L;
    __ cmpptr(Address(r15_thread, Thread::pending_exception_offset()), (int32_t) NULL_WORD);
    __ jcc(Assembler::zero, L);
    // Note: At some point we may want to unify this with the code
    // used in call_VM_base(); i.e., we should use the
    // StubRoutines::forward_exception code. For now this doesn't work
    // here because the rsp is not correctly set at this point.
    __ MacroAssembler::call_VM(noreg,
                               CAST_FROM_FN_PTR(address,
                               InterpreterRuntime::throw_pending_exception));
    __ should_not_reach_here();
    __ bind(L);
  }

  // do unlocking if necessary
  {
    Label L;
    __ movl(t, Address(method, methodOopDesc::access_flags_offset()));
    __ testl(t, JVM_ACC_SYNCHRONIZED);
    __ jcc(Assembler::zero, L);
    // the code below should be shared with interpreter macro
    // assembler implementation
    {
      Label unlock;
      // BasicObjectLock will be first in list, since this is a
      // synchronized method. However, need to check that the object
      // has not been unlocked by an explicit monitorexit bytecode.
      const Address monitor(rbp,
                            (intptr_t)(frame::interpreter_frame_initial_sp_offset *
                                       wordSize - sizeof(BasicObjectLock)));

      // monitor expect in c_rarg1 for slow unlock path
      __ lea(c_rarg1, monitor); // address of first monitor

      __ movptr(t, Address(c_rarg1, BasicObjectLock::obj_offset_in_bytes()));
      __ testptr(t, t);
      __ jcc(Assembler::notZero, unlock);

      // Entry already unlocked, need to throw exception
      __ MacroAssembler::call_VM(noreg,
                                 CAST_FROM_FN_PTR(address,
                   InterpreterRuntime::throw_illegal_monitor_state_exception));
      __ should_not_reach_here();

      __ bind(unlock);
      __ unlock_object(c_rarg1);
    }
    __ bind(L);
  }

  // jvmti support
  // Note: This must happen _after_ handling/throwing any exceptions since
  //       the exception handler code notifies the runtime of method exits
  //       too. If this happens before, method entry/exit notifications are
  //       not properly paired (was bug - gri 11/22/99).
  __ notify_method_exit(vtos, InterpreterMacroAssembler::NotifyJVMTI);

  // restore potential result in edx:eax, call result handler to
  // restore potential result in ST0 & handle result

  __ pop(ltos);
  __ pop(dtos);

  __ movptr(t, Address(rbp,
                       (frame::interpreter_frame_result_handler_offset) * wordSize));
  __ call(t);

  // remove activation
  __ movptr(t, Address(rbp,
                       frame::interpreter_frame_sender_sp_offset *
                       wordSize)); // get sender sp
  __ leave();                                // remove frame anchor
  __ pop(rdi);                               // get return address
  __ mov(rsp, t);                            // set sp to sender sp
  __ jmp(rdi);

  if (inc_counter) {
    // Handle overflow of counter and compile method
    __ bind(invocation_counter_overflow);
    generate_counter_overflow(&continue_after_compile);
  }

  return entry_point;
}

//
// Generic interpreted method entry to (asm) interpreter
//
address InterpreterGenerator::generate_normal_entry(bool synchronized) {
  // determine code generation flags
  bool inc_counter  = UseCompiler || CountCompiledCalls;

  // ebx: methodOop
  // r13: sender sp
  address entry_point = __ pc();

  const Address size_of_parameters(rbx,
                                   methodOopDesc::size_of_parameters_offset());
  const Address size_of_locals(rbx, methodOopDesc::size_of_locals_offset());
  const Address invocation_counter(rbx,
                                   methodOopDesc::invocation_counter_offset() +
                                   InvocationCounter::counter_offset());
  const Address access_flags(rbx, methodOopDesc::access_flags_offset());

  // get parameter size (always needed)
  __ load_unsigned_short(rcx, size_of_parameters);

  // rbx: methodOop
  // rcx: size of parameters
  // r13: sender_sp (could differ from sp+wordSize if we were called via c2i )

  __ load_unsigned_short(rdx, size_of_locals); // get size of locals in words
  __ subl(rdx, rcx); // rdx = no. of additional locals

  // YYY
//   __ incrementl(rdx);
//   __ andl(rdx, -2);

  // see if we've got enough room on the stack for locals plus overhead.
  generate_stack_overflow_check();

  // get return address
  __ pop(rax);

  // compute beginning of parameters (r14)
  __ lea(r14, Address(rsp, rcx, Address::times_8, -wordSize));

  // rdx - # of additional locals
  // allocate space for locals
  // explicitly initialize locals
  {
    Label exit, loop;
    __ testl(rdx, rdx);
    __ jcc(Assembler::lessEqual, exit); // do nothing if rdx <= 0
    __ bind(loop);
    __ push((int) NULL_WORD); // initialize local variables
    __ decrementl(rdx); // until everything initialized
    __ jcc(Assembler::greater, loop);
    __ bind(exit);
  }

  // (pre-)fetch invocation count
  if (inc_counter) {
    __ movl(rcx, invocation_counter);
  }
  // initialize fixed part of activation frame
  generate_fixed_frame(false);

  // make sure method is not native & not abstract
#ifdef ASSERT
  __ movl(rax, access_flags);
  {
    Label L;
    __ testl(rax, JVM_ACC_NATIVE);
    __ jcc(Assembler::zero, L);
    __ stop("tried to execute native method as non-native");
    __ bind(L);
  }
  {
    Label L;
    __ testl(rax, JVM_ACC_ABSTRACT);
    __ jcc(Assembler::zero, L);
    __ stop("tried to execute abstract method in interpreter");
    __ bind(L);
  }
#endif

  // Since at this point in the method invocation the exception
  // handler would try to exit the monitor of synchronized methods
  // which hasn't been entered yet, we set the thread local variable
  // _do_not_unlock_if_synchronized to true. The remove_activation
  // will check this flag.

  const Address do_not_unlock_if_synchronized(r15_thread,
        in_bytes(JavaThread::do_not_unlock_if_synchronized_offset()));
  __ movbool(do_not_unlock_if_synchronized, true);

  // increment invocation count & check for overflow
  Label invocation_counter_overflow;
  Label profile_method;
  Label profile_method_continue;
  if (inc_counter) {
    generate_counter_incr(&invocation_counter_overflow,
                          &profile_method,
                          &profile_method_continue);
    if (ProfileInterpreter) {
      __ bind(profile_method_continue);
    }
  }

  Label continue_after_compile;
  __ bind(continue_after_compile);

  // check for synchronized interpreted methods
  bang_stack_shadow_pages(false);

  // reset the _do_not_unlock_if_synchronized flag
  __ movbool(do_not_unlock_if_synchronized, false);

  // check for synchronized methods
  // Must happen AFTER invocation_counter check and stack overflow check,
  // so method is not locked if overflows.
  if (synchronized) {
    // Allocate monitor and lock method
    lock_method();
  } else {
    // no synchronization necessary
#ifdef ASSERT
    {
      Label L;
      __ movl(rax, access_flags);
      __ testl(rax, JVM_ACC_SYNCHRONIZED);
      __ jcc(Assembler::zero, L);
      __ stop("method needs synchronization");
      __ bind(L);
    }
#endif
  }

  // start execution
#ifdef ASSERT
  {
    Label L;
     const Address monitor_block_top (rbp,
                 frame::interpreter_frame_monitor_block_top_offset * wordSize);
    __ movptr(rax, monitor_block_top);
    __ cmpptr(rax, rsp);
    __ jcc(Assembler::equal, L);
    __ stop("broken stack frame setup in interpreter");
    __ bind(L);
  }
#endif

  // jvmti support
  __ notify_method_entry();

  __ dispatch_next(vtos);

  // invocation counter overflow
  if (inc_counter) {
    if (ProfileInterpreter) {
      // We have decided to profile this method in the interpreter
      __ bind(profile_method);
      __ call_VM(noreg, CAST_FROM_FN_PTR(address, InterpreterRuntime::profile_method));
      __ set_method_data_pointer_for_bcp();
      __ get_method(rbx);
      __ jmp(profile_method_continue);
    }
    // Handle overflow of counter and compile method
    __ bind(invocation_counter_overflow);
    generate_counter_overflow(&continue_after_compile);
  }

  return entry_point;
}

// Entry points
//
// Here we generate the various kind of entries into the interpreter.
// The two main entry type are generic bytecode methods and native
// call method.  These both come in synchronized and non-synchronized
// versions but the frame layout they create is very similar. The
// other method entry types are really just special purpose entries
// that are really entry and interpretation all in one. These are for
// trivial methods like accessor, empty, or special math methods.
//
// When control flow reaches any of the entry types for the interpreter
// the following holds ->
//
// Arguments:
//
// rbx: methodOop
//
// Stack layout immediately at entry
//
// [ return address     ] <--- rsp
// [ parameter n        ]
//   ...
// [ parameter 1        ]
// [ expression stack   ] (caller's java expression stack)

// Assuming that we don't go to one of the trivial specialized entries
// the stack will look like below when we are ready to execute the
// first bytecode (or call the native routine). The register usage
// will be as the template based interpreter expects (see
// interpreter_amd64.hpp).
//
// local variables follow incoming parameters immediately; i.e.
// the return address is moved to the end of the locals).
//
// [ monitor entry      ] <--- rsp
//   ...
// [ monitor entry      ]
// [ expr. stack bottom ]
// [ saved r13          ]
// [ current r14        ]
// [ methodOop          ]
// [ saved ebp          ] <--- rbp
// [ return address     ]
// [ local variable m   ]
//   ...
// [ local variable 1   ]
// [ parameter n        ]
//   ...
// [ parameter 1        ] <--- r14

address AbstractInterpreterGenerator::generate_method_entry(
                                        AbstractInterpreter::MethodKind kind) {
  // determine code generation flags
  bool synchronized = false;
  address entry_point = NULL;

  switch (kind) {
  case Interpreter::zerolocals             :                                                                             break;
  case Interpreter::zerolocals_synchronized: synchronized = true;                                                        break;
  case Interpreter::native                 : entry_point = ((InterpreterGenerator*) this)->generate_native_entry(false); break;
  case Interpreter::native_synchronized    : entry_point = ((InterpreterGenerator*) this)->generate_native_entry(true);  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     : // fall thru
  case Interpreter::java_lang_math_cos     : // fall thru
  case Interpreter::java_lang_math_tan     : // fall thru
  case Interpreter::java_lang_math_abs     : // fall thru
  case Interpreter::java_lang_math_log     : // fall thru
  case Interpreter::java_lang_math_log10   : // fall thru
  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();                                                       break;
  }

  if (entry_point) {
    return entry_point;
  }

  return ((InterpreterGenerator*) this)->
                                generate_normal_entry(synchronized);
}

// These should never be compiled since the interpreter will prefer
// the compiled version to the intrinsic version.
bool AbstractInterpreter::can_be_compiled(methodHandle m) {
  switch (method_kind(m)) {
    case Interpreter::java_lang_math_sin     : // fall thru
    case Interpreter::java_lang_math_cos     : // fall thru
    case Interpreter::java_lang_math_tan     : // fall thru
    case Interpreter::java_lang_math_abs     : // fall thru
    case Interpreter::java_lang_math_log     : // fall thru
    case Interpreter::java_lang_math_log10   : // fall thru
    case Interpreter::java_lang_math_sqrt    :
      return false;
    default:
      return true;
  }
}

// How much stack a method activation needs in words.
int AbstractInterpreter::size_top_interpreter_activation(methodOop method) {
  const int entry_size = frame::interpreter_frame_monitor_size();

  // total overhead size: entry_size + (saved rbp thru expr stack
  // bottom).  be sure to change this if you add/subtract anything
  // to/from the overhead area
  const int overhead_size =
    -(frame::interpreter_frame_initial_sp_offset) + entry_size;

  const int stub_code = frame::entry_frame_after_call_words;
  const int extra_stack = methodOopDesc::extra_stack_entries();
  const int method_stack = (method->max_locals() + method->max_stack() + extra_stack) *
                           Interpreter::stackElementWords;
  return (overhead_size + method_stack + stub_code);
}

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) {
  // Note: This calculation must exactly parallel the frame setup
  // in AbstractInterpreterGenerator::generate_method_entry.
  // If interpreter_frame!=NULL, set up the method, locals, and monitors.
  // The frame interpreter_frame, if not NULL, is guaranteed to be the
  // right size, as determined by a previous call to this method.
  // It is also guaranteed to be walkable even though it is in a skeletal state

  // fixed size of an interpreter frame:
  int max_locals = method->max_locals() * Interpreter::stackElementWords;
  int extra_locals = (method->max_locals() - method->size_of_parameters()) *
                     Interpreter::stackElementWords;

  int overhead = frame::sender_sp_offset -
                 frame::interpreter_frame_initial_sp_offset;
  // Our locals were accounted for by the caller (or last_frame_adjust
  // on the transistion) Since the callee parameters already account
  // for the callee's params we only need to account for the extra
  // locals.
  int size = overhead +
         (callee_locals - callee_param_count)*Interpreter::stackElementWords +
         moncount * frame::interpreter_frame_monitor_size() +
         tempcount* Interpreter::stackElementWords + popframe_extra_args;
  if (interpreter_frame != NULL) {
#ifdef ASSERT
    if (!EnableInvokeDynamic)
      // @@@ FIXME: Should we correct interpreter_frame_sender_sp in the calling sequences?
      // Probably, since deoptimization doesn't work yet.
      assert(caller->unextended_sp() == interpreter_frame->interpreter_frame_sender_sp(), "Frame not properly walkable");
    assert(caller->sp() == interpreter_frame->sender_sp(), "Frame not properly walkable(2)");
#endif

    interpreter_frame->interpreter_frame_set_method(method);
    // NOTE the difference in using sender_sp and
    // interpreter_frame_sender_sp interpreter_frame_sender_sp is
    // the original sp of the caller (the unextended_sp) and
    // sender_sp is fp+16 XXX
    intptr_t* locals = interpreter_frame->sender_sp() + max_locals - 1;

    interpreter_frame->interpreter_frame_set_locals(locals);
    BasicObjectLock* montop = interpreter_frame->interpreter_frame_monitor_begin();
    BasicObjectLock* monbot = montop - moncount;
    interpreter_frame->interpreter_frame_set_monitor_end(monbot);

    // Set last_sp
    intptr_t*  esp = (intptr_t*) monbot -
                     tempcount*Interpreter::stackElementWords -
                     popframe_extra_args;
    interpreter_frame->interpreter_frame_set_last_sp(esp);

    // All frames but the initial (oldest) interpreter frame we fill in have
    // a value for sender_sp that allows walking the stack but isn't
    // truly correct. Correct the value here.
    if (extra_locals != 0 &&
        interpreter_frame->sender_sp() ==
        interpreter_frame->interpreter_frame_sender_sp()) {
      interpreter_frame->set_interpreter_frame_sender_sp(caller->sp() +
                                                         extra_locals);
    }
    *interpreter_frame->interpreter_frame_cache_addr() =
      method->constants()->cache();
  }
  return size;
}

//-----------------------------------------------------------------------------
// Exceptions

void TemplateInterpreterGenerator::generate_throw_exception() {
  // Entry point in previous activation (i.e., if the caller was
  // interpreted)
  Interpreter::_rethrow_exception_entry = __ pc();
  // Restore sp to interpreter_frame_last_sp even though we are going
  // to empty the expression stack for the exception processing.
  __ movptr(Address(rbp, frame::interpreter_frame_last_sp_offset * wordSize), (int32_t)NULL_WORD);
  // rax: exception
  // rdx: return address/pc that threw exception
  __ restore_bcp();    // r13 points to call/send
  __ restore_locals();
  __ reinit_heapbase();  // restore r12 as heapbase.
  // Entry point for exceptions thrown within interpreter code
  Interpreter::_throw_exception_entry = __ pc();
  // expression stack is undefined here
  // rax: exception
  // r13: exception bcp
  __ verify_oop(rax);
  __ mov(c_rarg1, rax);

  // expression stack must be empty before entering the VM in case of
  // an exception
  __ empty_expression_stack();
  // find exception handler address and preserve exception oop
  __ call_VM(rdx,
             CAST_FROM_FN_PTR(address,
                          InterpreterRuntime::exception_handler_for_exception),
             c_rarg1);
  // rax: exception handler entry point
  // rdx: preserved exception oop
  // r13: bcp for exception handler
  __ push_ptr(rdx); // push exception which is now the only value on the stack
  __ jmp(rax); // jump to exception handler (may be _remove_activation_entry!)

  // If the exception is not handled in the current frame the frame is
  // removed and the exception is rethrown (i.e. exception
  // continuation is _rethrow_exception).
  //
  // Note: At this point the bci is still the bxi for the instruction
  // which caused the exception and the expression stack is
  // empty. Thus, for any VM calls at this point, GC will find a legal
  // oop map (with empty expression stack).

  // In current activation
  // tos: exception
  // esi: exception bcp

  //
  // JVMTI PopFrame support
  //

  Interpreter::_remove_activation_preserving_args_entry = __ pc();
  __ empty_expression_stack();
  // Set the popframe_processing bit in pending_popframe_condition
  // indicating that we are currently handling popframe, so that
  // call_VMs that may happen later do not trigger new popframe
  // handling cycles.
  __ movl(rdx, Address(r15_thread, JavaThread::popframe_condition_offset()));
  __ orl(rdx, JavaThread::popframe_processing_bit);
  __ movl(Address(r15_thread, JavaThread::popframe_condition_offset()), rdx);

  {
    // Check to see whether we are returning to a deoptimized frame.
    // (The PopFrame call ensures that the caller of the popped frame is
    // either interpreted or compiled and deoptimizes it if compiled.)
    // In this case, we can't call dispatch_next() after the frame is
    // popped, but instead must save the incoming arguments and restore
    // them after deoptimization has occurred.
    //
    // Note that we don't compare the return PC against the
    // deoptimization blob's unpack entry because of the presence of
    // adapter frames in C2.
    Label caller_not_deoptimized;
    __ movptr(c_rarg1, Address(rbp, frame::return_addr_offset * wordSize));
    __ super_call_VM_leaf(CAST_FROM_FN_PTR(address,
                               InterpreterRuntime::interpreter_contains), c_rarg1);
    __ testl(rax, rax);
    __ jcc(Assembler::notZero, caller_not_deoptimized);

    // Compute size of arguments for saving when returning to
    // deoptimized caller
    __ get_method(rax);
    __ load_unsigned_short(rax, Address(rax, in_bytes(methodOopDesc::
                                                size_of_parameters_offset())));
    __ shll(rax, Interpreter::logStackElementSize);
    __ restore_locals(); // XXX do we need this?
    __ subptr(r14, rax);
    __ addptr(r14, wordSize);
    // Save these arguments
    __ super_call_VM_leaf(CAST_FROM_FN_PTR(address,
                                           Deoptimization::
                                           popframe_preserve_args),
                          r15_thread, rax, r14);

    __ remove_activation(vtos, rdx,
                         /* throw_monitor_exception */ false,
                         /* install_monitor_exception */ false,
                         /* notify_jvmdi */ false);

    // Inform deoptimization that it is responsible for restoring
    // these arguments
    __ movl(Address(r15_thread, JavaThread::popframe_condition_offset()),
            JavaThread::popframe_force_deopt_reexecution_bit);

    // Continue in deoptimization handler
    __ jmp(rdx);

    __ bind(caller_not_deoptimized);
  }

  __ remove_activation(vtos, rdx, /* rdx result (retaddr) is not used */
                       /* throw_monitor_exception */ false,
                       /* install_monitor_exception */ false,
                       /* notify_jvmdi */ false);

  // Finish with popframe handling
  // A previous I2C followed by a deoptimization might have moved the
  // outgoing arguments further up the stack. PopFrame expects the
  // mutations to those outgoing arguments to be preserved and other
  // constraints basically require this frame to look exactly as
  // though it had previously invoked an interpreted activation with
  // no space between the top of the expression stack (current
  // last_sp) and the top of stack. Rather than force deopt to
  // maintain this kind of invariant all the time we call a small
  // fixup routine to move the mutated arguments onto the top of our
  // expression stack if necessary.
  __ mov(c_rarg1, rsp);
  __ movptr(c_rarg2, Address(rbp, frame::interpreter_frame_last_sp_offset * wordSize));
  // PC must point into interpreter here
  __ set_last_Java_frame(noreg, rbp, __ pc());
  __ super_call_VM_leaf(CAST_FROM_FN_PTR(address, InterpreterRuntime::popframe_move_outgoing_args), r15_thread, c_rarg1, c_rarg2);
  __ reset_last_Java_frame(true, true);
  // Restore the last_sp and null it out
  __ movptr(rsp, Address(rbp, frame::interpreter_frame_last_sp_offset * wordSize));
  __ movptr(Address(rbp, frame::interpreter_frame_last_sp_offset * wordSize), (int32_t)NULL_WORD);

  __ restore_bcp();  // XXX do we need this?
  __ restore_locals(); // XXX do we need this?
  // The method data pointer was incremented already during
  // call profiling. We have to restore the mdp for the current bcp.
  if (ProfileInterpreter) {
    __ set_method_data_pointer_for_bcp();
  }

  // Clear the popframe condition flag
  __ movl(Address(r15_thread, JavaThread::popframe_condition_offset()),
          JavaThread::popframe_inactive);

  __ dispatch_next(vtos);
  // end of PopFrame support

  Interpreter::_remove_activation_entry = __ pc();

  // preserve exception over this code sequence
  __ pop_ptr(rax);
  __ movptr(Address(r15_thread, JavaThread::vm_result_offset()), rax);
  // remove the activation (without doing throws on illegalMonitorExceptions)
  __ remove_activation(vtos, rdx, false, true, false);
  // restore exception
  __ movptr(rax, Address(r15_thread, JavaThread::vm_result_offset()));
  __ movptr(Address(r15_thread, JavaThread::vm_result_offset()), (int32_t)NULL_WORD);
  __ verify_oop(rax);

  // In between activations - previous activation type unknown yet
  // compute continuation point - the continuation point expects the
  // following registers set up:
  //
  // rax: exception
  // rdx: return address/pc that threw exception
  // rsp: expression stack of caller
  // rbp: ebp of caller
  __ push(rax);                                  // save exception
  __ push(rdx);                                  // save return address
  __ super_call_VM_leaf(CAST_FROM_FN_PTR(address,
                          SharedRuntime::exception_handler_for_return_address),
                        r15_thread, rdx);
  __ mov(rbx, rax);                              // save exception handler
  __ pop(rdx);                                   // restore return address
  __ pop(rax);                                   // restore exception
  // Note that an "issuing PC" is actually the next PC after the call
  __ jmp(rbx);                                   // jump to exception
                                                 // handler of caller
}


//
// JVMTI ForceEarlyReturn support
//
address TemplateInterpreterGenerator::generate_earlyret_entry_for(TosState state) {
  address entry = __ pc();

  __ restore_bcp();
  __ restore_locals();
  __ empty_expression_stack();
  __ load_earlyret_value(state);

  __ movptr(rdx, Address(r15_thread, JavaThread::jvmti_thread_state_offset()));
  Address cond_addr(rdx, JvmtiThreadState::earlyret_state_offset());

  // Clear the earlyret state
  __ movl(cond_addr, JvmtiThreadState::earlyret_inactive);

  __ remove_activation(state, rsi,
                       false, /* throw_monitor_exception */
                       false, /* install_monitor_exception */
                       true); /* notify_jvmdi */
  __ jmp(rsi);

  return entry;
} // end of ForceEarlyReturn support


//-----------------------------------------------------------------------------
// Helper for vtos entry point generation

void TemplateInterpreterGenerator::set_vtos_entry_points(Template* t,
                                                         address& bep,
                                                         address& cep,
                                                         address& sep,
                                                         address& aep,
                                                         address& iep,
                                                         address& lep,
                                                         address& fep,
                                                         address& dep,
                                                         address& vep) {
  assert(t->is_valid() && t->tos_in() == vtos, "illegal template");
  Label L;
  aep = __ pc();  __ push_ptr();  __ jmp(L);
  fep = __ pc();  __ push_f();    __ jmp(L);
  dep = __ pc();  __ push_d();    __ jmp(L);
  lep = __ pc();  __ push_l();    __ jmp(L);
  bep = cep = sep =
  iep = __ pc();  __ push_i();
  vep = __ pc();
  __ bind(L);
  generate_and_dispatch(t);
}


//-----------------------------------------------------------------------------
// Generation of individual instructions

// helpers for generate_and_dispatch


InterpreterGenerator::InterpreterGenerator(StubQueue* code)
  : TemplateInterpreterGenerator(code) {
   generate_all(); // down here so it can be "virtual"
}

//-----------------------------------------------------------------------------

// Non-product code
#ifndef PRODUCT
address TemplateInterpreterGenerator::generate_trace_code(TosState state) {
  address entry = __ pc();

  __ push(state);
  __ push(c_rarg0);
  __ push(c_rarg1);
  __ push(c_rarg2);
  __ push(c_rarg3);
  __ mov(c_rarg2, rax);  // Pass itos
#ifdef _WIN64
  __ movflt(xmm3, xmm0); // Pass ftos
#endif
  __ call_VM(noreg,
             CAST_FROM_FN_PTR(address, SharedRuntime::trace_bytecode),
             c_rarg1, c_rarg2, c_rarg3);
  __ pop(c_rarg3);
  __ pop(c_rarg2);
  __ pop(c_rarg1);
  __ pop(c_rarg0);
  __ pop(state);
  __ ret(0);                                   // return from result handler

  return entry;
}

void TemplateInterpreterGenerator::count_bytecode() {
  __ incrementl(ExternalAddress((address) &BytecodeCounter::_counter_value));
}

void TemplateInterpreterGenerator::histogram_bytecode(Template* t) {
  __ incrementl(ExternalAddress((address) &BytecodeHistogram::_counters[t->bytecode()]));
}

void TemplateInterpreterGenerator::histogram_bytecode_pair(Template* t) {
  __ mov32(rbx, ExternalAddress((address) &BytecodePairHistogram::_index));
  __ shrl(rbx, BytecodePairHistogram::log2_number_of_codes);
  __ orl(rbx,
         ((int) t->bytecode()) <<
         BytecodePairHistogram::log2_number_of_codes);
  __ mov32(ExternalAddress((address) &BytecodePairHistogram::_index), rbx);
  __ lea(rscratch1, ExternalAddress((address) BytecodePairHistogram::_counters));
  __ incrementl(Address(rscratch1, rbx, Address::times_4));
}


void TemplateInterpreterGenerator::trace_bytecode(Template* t) {
  // Call a little run-time stub to avoid blow-up for each bytecode.
  // The run-time runtime saves the right registers, depending on
  // the tosca in-state for the given template.

  assert(Interpreter::trace_code(t->tos_in()) != NULL,
         "entry must have been generated");
  __ mov(r12, rsp); // remember sp (can only use r12 if not using call_VM)
  __ andptr(rsp, -16); // align stack as required by ABI
  __ call(RuntimeAddress(Interpreter::trace_code(t->tos_in())));
  __ mov(rsp, r12); // restore sp
  __ reinit_heapbase();
}


void TemplateInterpreterGenerator::stop_interpreter_at() {
  Label L;
  __ cmp32(ExternalAddress((address) &BytecodeCounter::_counter_value),
           StopInterpreterAt);
  __ jcc(Assembler::notEqual, L);
  __ int3();
  __ bind(L);
}
#endif // !PRODUCT
#endif // ! CC_INTERP