xref: /openjdk9/hotspot/src/share/vm/opto/parseHelper.cpp

/*
 * Copyright (c) 1998, 2014, 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 "classfile/systemDictionary.hpp"
#include "compiler/compileLog.hpp"
#include "oops/objArrayKlass.hpp"
#include "opto/addnode.hpp"
#include "opto/memnode.hpp"
#include "opto/mulnode.hpp"
#include "opto/parse.hpp"
#include "opto/rootnode.hpp"
#include "opto/runtime.hpp"
#include "runtime/sharedRuntime.hpp"

//------------------------------make_dtrace_method_entry_exit ----------------
// Dtrace -- record entry or exit of a method if compiled with dtrace support
void GraphKit::make_dtrace_method_entry_exit(ciMethod* method, bool is_entry) {
  const TypeFunc *call_type    = OptoRuntime::dtrace_method_entry_exit_Type();
  address         call_address = is_entry ? CAST_FROM_FN_PTR(address, SharedRuntime::dtrace_method_entry) :
                                            CAST_FROM_FN_PTR(address, SharedRuntime::dtrace_method_exit);
  const char     *call_name    = is_entry ? "dtrace_method_entry" : "dtrace_method_exit";

  // Get base of thread-local storage area
  Node* thread = _gvn.transform( new ThreadLocalNode() );

  // Get method
  const TypePtr* method_type = TypeMetadataPtr::make(method);
  Node *method_node = _gvn.transform(ConNode::make(method_type));

  kill_dead_locals();

  // For some reason, this call reads only raw memory.
  const TypePtr* raw_adr_type = TypeRawPtr::BOTTOM;
  make_runtime_call(RC_LEAF | RC_NARROW_MEM,
                    call_type, call_address,
                    call_name, raw_adr_type,
                    thread, method_node);
}


//=============================================================================
//------------------------------do_checkcast-----------------------------------
void Parse::do_checkcast() {
  bool will_link;
  ciKlass* klass = iter().get_klass(will_link);

  Node *obj = peek();

  // Throw uncommon trap if class is not loaded or the value we are casting
  // _from_ is not loaded, and value is not null.  If the value _is_ NULL,
  // then the checkcast does nothing.
  const TypeOopPtr *tp = _gvn.type(obj)->isa_oopptr();
  if (!will_link || (tp && tp->klass() && !tp->klass()->is_loaded())) {
    if (C->log() != NULL) {
      if (!will_link) {
        C->log()->elem("assert_null reason='checkcast' klass='%d'",
                       C->log()->identify(klass));
      }
      if (tp && tp->klass() && !tp->klass()->is_loaded()) {
        // %%% Cannot happen?
        C->log()->elem("assert_null reason='checkcast source' klass='%d'",
                       C->log()->identify(tp->klass()));
      }
    }
    null_assert(obj);
    assert( stopped() || _gvn.type(peek())->higher_equal(TypePtr::NULL_PTR), "what's left behind is null" );
    if (!stopped()) {
      profile_null_checkcast();
    }
    return;
  }

  Node *res = gen_checkcast(obj, makecon(TypeKlassPtr::make(klass)) );

  // Pop from stack AFTER gen_checkcast because it can uncommon trap and
  // the debug info has to be correct.
  pop();
  push(res);
}


//------------------------------do_instanceof----------------------------------
void Parse::do_instanceof() {
  if (stopped())  return;
  // We would like to return false if class is not loaded, emitting a
  // dependency, but Java requires instanceof to load its operand.

  // Throw uncommon trap if class is not loaded
  bool will_link;
  ciKlass* klass = iter().get_klass(will_link);

  if (!will_link) {
    if (C->log() != NULL) {
      C->log()->elem("assert_null reason='instanceof' klass='%d'",
                     C->log()->identify(klass));
    }
    null_assert(peek());
    assert( stopped() || _gvn.type(peek())->higher_equal(TypePtr::NULL_PTR), "what's left behind is null" );
    if (!stopped()) {
      // The object is now known to be null.
      // Shortcut the effect of gen_instanceof and return "false" directly.
      pop();                   // pop the null
      push(_gvn.intcon(0));    // push false answer
    }
    return;
  }

  // Push the bool result back on stack
  Node* res = gen_instanceof(peek(), makecon(TypeKlassPtr::make(klass)), true);

  // Pop from stack AFTER gen_instanceof because it can uncommon trap.
  pop();
  push(res);
}

//------------------------------array_store_check------------------------------
// pull array from stack and check that the store is valid
void Parse::array_store_check() {

  // Shorthand access to array store elements without popping them.
  Node *obj = peek(0);
  Node *idx = peek(1);
  Node *ary = peek(2);

  if (_gvn.type(obj) == TypePtr::NULL_PTR) {
    // There's never a type check on null values.
    // This cutout lets us avoid the uncommon_trap(Reason_array_check)
    // below, which turns into a performance liability if the
    // gen_checkcast folds up completely.
    return;
  }

  // Extract the array klass type
  int klass_offset = oopDesc::klass_offset_in_bytes();
  Node* p = basic_plus_adr( ary, ary, klass_offset );
  // p's type is array-of-OOPS plus klass_offset
  Node* array_klass = _gvn.transform(LoadKlassNode::make(_gvn, NULL, immutable_memory(), p, TypeInstPtr::KLASS));
  // Get the array klass
  const TypeKlassPtr *tak = _gvn.type(array_klass)->is_klassptr();

  // The type of array_klass is usually INexact array-of-oop.  Heroically
  // cast array_klass to EXACT array and uncommon-trap if the cast fails.
  // Make constant out of the inexact array klass, but use it only if the cast
  // succeeds.
  bool always_see_exact_class = false;
  if (MonomorphicArrayCheck
      && !too_many_traps(Deoptimization::Reason_array_check)
      && !tak->klass_is_exact()
      && tak != TypeKlassPtr::OBJECT) {
      // Regarding the fourth condition in the if-statement from above:
      //
      // If the compiler has determined that the type of array 'ary' (represented
      // by 'array_klass') is java/lang/Object, the compiler must not assume that
      // the array 'ary' is monomorphic.
      //
      // If 'ary' were of type java/lang/Object, this arraystore would have to fail,
      // because it is not possible to perform a arraystore into an object that is not
      // a "proper" array.
      //
      // Therefore, let's obtain at runtime the type of 'ary' and check if we can still
      // successfully perform the store.
      //
      // The implementation reasons for the condition are the following:
      //
      // java/lang/Object is the superclass of all arrays, but it is represented by the VM
      // as an InstanceKlass. The checks generated by gen_checkcast() (see below) expect
      // 'array_klass' to be ObjArrayKlass, which can result in invalid memory accesses.
      //
      // See issue JDK-8057622 for details.

    always_see_exact_class = true;
    // (If no MDO at all, hope for the best, until a trap actually occurs.)

    // Make a constant out of the inexact array klass
    const TypeKlassPtr *extak = tak->cast_to_exactness(true)->is_klassptr();
    Node* con = makecon(extak);
    Node* cmp = _gvn.transform(new CmpPNode( array_klass, con ));
    Node* bol = _gvn.transform(new BoolNode( cmp, BoolTest::eq ));
    Node* ctrl= control();
    { BuildCutout unless(this, bol, PROB_MAX);
      uncommon_trap(Deoptimization::Reason_array_check,
                    Deoptimization::Action_maybe_recompile,
                    tak->klass());
    }
    if (stopped()) {          // MUST uncommon-trap?
      set_control(ctrl);      // Then Don't Do It, just fall into the normal checking
    } else {                  // Cast array klass to exactness:
      // Use the exact constant value we know it is.
      replace_in_map(array_klass,con);
      CompileLog* log = C->log();
      if (log != NULL) {
        log->elem("cast_up reason='monomorphic_array' from='%d' to='(exact)'",
                  log->identify(tak->klass()));
      }
      array_klass = con;      // Use cast value moving forward
    }
  }

  // Come here for polymorphic array klasses

  // Extract the array element class
  int element_klass_offset = in_bytes(ObjArrayKlass::element_klass_offset());
  Node *p2 = basic_plus_adr(array_klass, array_klass, element_klass_offset);
  // We are allowed to use the constant type only if cast succeeded. If always_see_exact_class is true,
  // we must set a control edge from the IfTrue node created by the uncommon_trap above to the
  // LoadKlassNode.
  Node* a_e_klass = _gvn.transform(LoadKlassNode::make(_gvn, always_see_exact_class ? control() : NULL,
                                                       immutable_memory(), p2, tak));

  // Check (the hard way) and throw if not a subklass.
  // Result is ignored, we just need the CFG effects.
  gen_checkcast(obj, a_e_klass);
}


void Parse::emit_guard_for_new(ciInstanceKlass* klass) {
  // Emit guarded new
  //   if (klass->_init_thread != current_thread ||
  //       klass->_init_state != being_initialized)
  //      uncommon_trap
  Node* cur_thread = _gvn.transform( new ThreadLocalNode() );
  Node* merge = new RegionNode(3);
  _gvn.set_type(merge, Type::CONTROL);
  Node* kls = makecon(TypeKlassPtr::make(klass));

  Node* init_thread_offset = _gvn.MakeConX(in_bytes(InstanceKlass::init_thread_offset()));
  Node* adr_node = basic_plus_adr(kls, kls, init_thread_offset);
  Node* init_thread = make_load(NULL, adr_node, TypeRawPtr::BOTTOM, T_ADDRESS, MemNode::unordered);
  Node *tst   = Bool( CmpP( init_thread, cur_thread), BoolTest::eq);
  IfNode* iff = create_and_map_if(control(), tst, PROB_ALWAYS, COUNT_UNKNOWN);
  set_control(IfTrue(iff));
  merge->set_req(1, IfFalse(iff));

  Node* init_state_offset = _gvn.MakeConX(in_bytes(InstanceKlass::init_state_offset()));
  adr_node = basic_plus_adr(kls, kls, init_state_offset);
  // Use T_BOOLEAN for InstanceKlass::_init_state so the compiler
  // can generate code to load it as unsigned byte.
  Node* init_state = make_load(NULL, adr_node, TypeInt::UBYTE, T_BOOLEAN, MemNode::unordered);
  Node* being_init = _gvn.intcon(InstanceKlass::being_initialized);
  tst   = Bool( CmpI( init_state, being_init), BoolTest::eq);
  iff = create_and_map_if(control(), tst, PROB_ALWAYS, COUNT_UNKNOWN);
  set_control(IfTrue(iff));
  merge->set_req(2, IfFalse(iff));

  PreserveJVMState pjvms(this);
  record_for_igvn(merge);
  set_control(merge);

  uncommon_trap(Deoptimization::Reason_uninitialized,
                Deoptimization::Action_reinterpret,
                klass);
}


//------------------------------do_new-----------------------------------------
void Parse::do_new() {
  kill_dead_locals();

  bool will_link;
  ciInstanceKlass* klass = iter().get_klass(will_link)->as_instance_klass();
  assert(will_link, "_new: typeflow responsibility");

  // Should initialize, or throw an InstantiationError?
  if (!klass->is_initialized() && !klass->is_being_initialized() ||
      klass->is_abstract() || klass->is_interface() ||
      klass->name() == ciSymbol::java_lang_Class() ||
      iter().is_unresolved_klass()) {
    uncommon_trap(Deoptimization::Reason_uninitialized,
                  Deoptimization::Action_reinterpret,
                  klass);
    return;
  }
  if (klass->is_being_initialized()) {
    emit_guard_for_new(klass);
  }

  Node* kls = makecon(TypeKlassPtr::make(klass));
  Node* obj = new_instance(kls);

  // Push resultant oop onto stack
  push(obj);

  // Keep track of whether opportunities exist for StringBuilder
  // optimizations.
  if (OptimizeStringConcat &&
      (klass == C->env()->StringBuilder_klass() ||
       klass == C->env()->StringBuffer_klass())) {
    C->set_has_stringbuilder(true);
  }

  // Keep track of boxed values for EliminateAutoBox optimizations.
  if (C->eliminate_boxing() && klass->is_box_klass()) {
    C->set_has_boxed_value(true);
  }
}

#ifndef PRODUCT
//------------------------------dump_map_adr_mem-------------------------------
// Debug dump of the mapping from address types to MergeMemNode indices.
void Parse::dump_map_adr_mem() const {
  tty->print_cr("--- Mapping from address types to memory Nodes ---");
  MergeMemNode *mem = map() == NULL ? NULL : (map()->memory()->is_MergeMem() ?
                                      map()->memory()->as_MergeMem() : NULL);
  for (uint i = 0; i < (uint)C->num_alias_types(); i++) {
    C->alias_type(i)->print_on(tty);
    tty->print("\t");
    // Node mapping, if any
    if (mem && i < mem->req() && mem->in(i) && mem->in(i) != mem->empty_memory()) {
      mem->in(i)->dump();
    } else {
      tty->cr();
    }
  }
}

#endif


//=============================================================================
//
// parser methods for profiling


//----------------------test_counter_against_threshold ------------------------
void Parse::test_counter_against_threshold(Node* cnt, int limit) {
  // Test the counter against the limit and uncommon trap if greater.

  // This code is largely copied from the range check code in
  // array_addressing()

  // Test invocation count vs threshold
  Node *threshold = makecon(TypeInt::make(limit));
  Node *chk   = _gvn.transform( new CmpUNode( cnt, threshold) );
  BoolTest::mask btest = BoolTest::lt;
  Node *tst   = _gvn.transform( new BoolNode( chk, btest) );
  // Branch to failure if threshold exceeded
  { BuildCutout unless(this, tst, PROB_ALWAYS);
    uncommon_trap(Deoptimization::Reason_age,
                  Deoptimization::Action_maybe_recompile);
  }
}

//----------------------increment_and_test_invocation_counter-------------------
void Parse::increment_and_test_invocation_counter(int limit) {
  if (!count_invocations()) return;

  // Get the Method* node.
  ciMethod* m = method();
  MethodCounters* counters_adr = m->ensure_method_counters();
  if (counters_adr == NULL) {
    C->record_failure("method counters allocation failed");
    return;
  }

  Node* ctrl = control();
  const TypePtr* adr_type = TypeRawPtr::make((address) counters_adr);
  Node *counters_node = makecon(adr_type);
  Node* adr_iic_node = basic_plus_adr(counters_node, counters_node,
    MethodCounters::interpreter_invocation_counter_offset_in_bytes());
  Node* cnt = make_load(ctrl, adr_iic_node, TypeInt::INT, T_INT, adr_type, MemNode::unordered);

  test_counter_against_threshold(cnt, limit);

  // Add one to the counter and store
  Node* incr = _gvn.transform(new AddINode(cnt, _gvn.intcon(1)));
  store_to_memory(ctrl, adr_iic_node, incr, T_INT, adr_type, MemNode::unordered);
}

//----------------------------method_data_addressing---------------------------
Node* Parse::method_data_addressing(ciMethodData* md, ciProfileData* data, ByteSize counter_offset, Node* idx, uint stride) {
  // Get offset within MethodData* of the data array
  ByteSize data_offset = MethodData::data_offset();

  // Get cell offset of the ProfileData within data array
  int cell_offset = md->dp_to_di(data->dp());

  // Add in counter_offset, the # of bytes into the ProfileData of counter or flag
  int offset = in_bytes(data_offset) + cell_offset + in_bytes(counter_offset);

  const TypePtr* adr_type = TypeMetadataPtr::make(md);
  Node* mdo = makecon(adr_type);
  Node* ptr = basic_plus_adr(mdo, mdo, offset);

  if (stride != 0) {
    Node* str = _gvn.MakeConX(stride);
    Node* scale = _gvn.transform( new MulXNode( idx, str ) );
    ptr   = _gvn.transform( new AddPNode( mdo, ptr, scale ) );
  }

  return ptr;
}

//--------------------------increment_md_counter_at----------------------------
void Parse::increment_md_counter_at(ciMethodData* md, ciProfileData* data, ByteSize counter_offset, Node* idx, uint stride) {
  Node* adr_node = method_data_addressing(md, data, counter_offset, idx, stride);

  const TypePtr* adr_type = _gvn.type(adr_node)->is_ptr();
  Node* cnt  = make_load(NULL, adr_node, TypeInt::INT, T_INT, adr_type, MemNode::unordered);
  Node* incr = _gvn.transform(new AddINode(cnt, _gvn.intcon(DataLayout::counter_increment)));
  store_to_memory(NULL, adr_node, incr, T_INT, adr_type, MemNode::unordered);
}

//--------------------------test_for_osr_md_counter_at-------------------------
void Parse::test_for_osr_md_counter_at(ciMethodData* md, ciProfileData* data, ByteSize counter_offset, int limit) {
  Node* adr_node = method_data_addressing(md, data, counter_offset);

  const TypePtr* adr_type = _gvn.type(adr_node)->is_ptr();
  Node* cnt  = make_load(NULL, adr_node, TypeInt::INT, T_INT, adr_type, MemNode::unordered);

  test_counter_against_threshold(cnt, limit);
}

//-------------------------------set_md_flag_at--------------------------------
void Parse::set_md_flag_at(ciMethodData* md, ciProfileData* data, int flag_constant) {
  Node* adr_node = method_data_addressing(md, data, DataLayout::flags_offset());

  const TypePtr* adr_type = _gvn.type(adr_node)->is_ptr();
  Node* flags = make_load(NULL, adr_node, TypeInt::BYTE, T_BYTE, adr_type, MemNode::unordered);
  Node* incr = _gvn.transform(new OrINode(flags, _gvn.intcon(flag_constant)));
  store_to_memory(NULL, adr_node, incr, T_BYTE, adr_type, MemNode::unordered);
}

//----------------------------profile_taken_branch-----------------------------
void Parse::profile_taken_branch(int target_bci, bool force_update) {
  // This is a potential osr_site if we have a backedge.
  int cur_bci = bci();
  bool osr_site =
    (target_bci <= cur_bci) && count_invocations() && UseOnStackReplacement;

  // If we are going to OSR, restart at the target bytecode.
  set_bci(target_bci);

  // To do: factor out the the limit calculations below. These duplicate
  // the similar limit calculations in the interpreter.

  if (method_data_update() || force_update) {
    ciMethodData* md = method()->method_data();
    assert(md != NULL, "expected valid ciMethodData");
    ciProfileData* data = md->bci_to_data(cur_bci);
    assert(data->is_JumpData(), "need JumpData for taken branch");
    increment_md_counter_at(md, data, JumpData::taken_offset());
  }

  // In the new tiered system this is all we need to do. In the old
  // (c2 based) tiered sytem we must do the code below.
#ifndef TIERED
  if (method_data_update()) {
    ciMethodData* md = method()->method_data();
    if (osr_site) {
      ciProfileData* data = md->bci_to_data(cur_bci);
      int limit = (CompileThreshold
                   * (OnStackReplacePercentage - InterpreterProfilePercentage)) / 100;
      test_for_osr_md_counter_at(md, data, JumpData::taken_offset(), limit);
    }
  } else {
    // With method data update off, use the invocation counter to trigger an
    // OSR compilation, as done in the interpreter.
    if (osr_site) {
      int limit = (CompileThreshold * OnStackReplacePercentage) / 100;
      increment_and_test_invocation_counter(limit);
    }
  }
#endif // TIERED

  // Restore the original bytecode.
  set_bci(cur_bci);
}

//--------------------------profile_not_taken_branch---------------------------
void Parse::profile_not_taken_branch(bool force_update) {

  if (method_data_update() || force_update) {
    ciMethodData* md = method()->method_data();
    assert(md != NULL, "expected valid ciMethodData");
    ciProfileData* data = md->bci_to_data(bci());
    assert(data->is_BranchData(), "need BranchData for not taken branch");
    increment_md_counter_at(md, data, BranchData::not_taken_offset());
  }

}

//---------------------------------profile_call--------------------------------
void Parse::profile_call(Node* receiver) {
  if (!method_data_update()) return;

  switch (bc()) {
  case Bytecodes::_invokevirtual:
  case Bytecodes::_invokeinterface:
    profile_receiver_type(receiver);
    break;
  case Bytecodes::_invokestatic:
  case Bytecodes::_invokedynamic:
  case Bytecodes::_invokespecial:
    profile_generic_call();
    break;
  default: fatal("unexpected call bytecode");
  }
}

//------------------------------profile_generic_call---------------------------
void Parse::profile_generic_call() {
  assert(method_data_update(), "must be generating profile code");

  ciMethodData* md = method()->method_data();
  assert(md != NULL, "expected valid ciMethodData");
  ciProfileData* data = md->bci_to_data(bci());
  assert(data->is_CounterData(), "need CounterData for not taken branch");
  increment_md_counter_at(md, data, CounterData::count_offset());
}

//-----------------------------profile_receiver_type---------------------------
void Parse::profile_receiver_type(Node* receiver) {
  assert(method_data_update(), "must be generating profile code");

  ciMethodData* md = method()->method_data();
  assert(md != NULL, "expected valid ciMethodData");
  ciProfileData* data = md->bci_to_data(bci());
  assert(data->is_ReceiverTypeData(), "need ReceiverTypeData here");

  // Skip if we aren't tracking receivers
  if (TypeProfileWidth < 1) {
    increment_md_counter_at(md, data, CounterData::count_offset());
    return;
  }
  ciReceiverTypeData* rdata = (ciReceiverTypeData*)data->as_ReceiverTypeData();

  Node* method_data = method_data_addressing(md, rdata, in_ByteSize(0));

  // Using an adr_type of TypePtr::BOTTOM to work around anti-dep problems.
  // A better solution might be to use TypeRawPtr::BOTTOM with RC_NARROW_MEM.
  make_runtime_call(RC_LEAF, OptoRuntime::profile_receiver_type_Type(),
                    CAST_FROM_FN_PTR(address,
                                     OptoRuntime::profile_receiver_type_C),
                    "profile_receiver_type_C",
                    TypePtr::BOTTOM,
                    method_data, receiver);
}

//---------------------------------profile_ret---------------------------------
void Parse::profile_ret(int target_bci) {
  if (!method_data_update()) return;

  // Skip if we aren't tracking ret targets
  if (TypeProfileWidth < 1) return;

  ciMethodData* md = method()->method_data();
  assert(md != NULL, "expected valid ciMethodData");
  ciProfileData* data = md->bci_to_data(bci());
  assert(data->is_RetData(), "need RetData for ret");
  ciRetData* ret_data = (ciRetData*)data->as_RetData();

  // Look for the target_bci is already in the table
  uint row;
  bool table_full = true;
  for (row = 0; row < ret_data->row_limit(); row++) {
    int key = ret_data->bci(row);
    table_full &= (key != RetData::no_bci);
    if (key == target_bci) break;
  }

  if (row >= ret_data->row_limit()) {
    // The target_bci was not found in the table.
    if (!table_full) {
      // XXX: Make slow call to update RetData
    }
    return;
  }

  // the target_bci is already in the table
  increment_md_counter_at(md, data, RetData::bci_count_offset(row));
}

//--------------------------profile_null_checkcast----------------------------
void Parse::profile_null_checkcast() {
  // Set the null-seen flag, done in conjunction with the usual null check. We
  // never unset the flag, so this is a one-way switch.
  if (!method_data_update()) return;

  ciMethodData* md = method()->method_data();
  assert(md != NULL, "expected valid ciMethodData");
  ciProfileData* data = md->bci_to_data(bci());
  assert(data->is_BitData(), "need BitData for checkcast");
  set_md_flag_at(md, data, BitData::null_seen_byte_constant());
}

//-----------------------------profile_switch_case-----------------------------
void Parse::profile_switch_case(int table_index) {
  if (!method_data_update()) return;

  ciMethodData* md = method()->method_data();
  assert(md != NULL, "expected valid ciMethodData");

  ciProfileData* data = md->bci_to_data(bci());
  assert(data->is_MultiBranchData(), "need MultiBranchData for switch case");
  if (table_index >= 0) {
    increment_md_counter_at(md, data, MultiBranchData::case_count_offset(table_index));
  } else {
    increment_md_counter_at(md, data, MultiBranchData::default_count_offset());
  }
}