C++ CompileLog类代码示例

//------------------------------Ideal------------------------------------------
// Check for the case of comparing an unknown klass loaded from the primary
// super-type array vs a known klass with no subtypes.  This amounts to
// checking to see an unknown klass subtypes a known klass with no subtypes;
// this only happens on an exact match.  We can shorten this test by 1 load.
Node *CmpPNode::Ideal( PhaseGVN *phase, bool can_reshape ) {
  // Constant pointer on right?
  const Type *t2 = phase->type(in(2));
  if( t2 == TypePtr::NULL_PTR || !t2->singleton() || t2 == Type::TOP )
    return NULL;

  // Now check for LoadKlass on left.
  Node *ldk1 = in(1);
  if( ldk1->Opcode() != Op_LoadKlass )
    return NULL;
  // Check for loading from primary supertype array.
  // Any nested loadklass from loadklass+con must be from the p.s.array
  Node *adr1 = ldk1->in(MemNode::Address);
  if( adr1->Opcode() != Op_AddP )
    return NULL;
  Node *ldk2 = adr1->in(AddPNode::Address);
  Node *off2 = adr1->in(AddPNode::Offset);
  if( ldk2->Opcode() != Op_LoadKlass )
    return NULL;
  jint con2;
  if( !off2->get_int(&con2) )
    return NULL;

  // Get the constant klass we are comparing to.
  ciType *superklass = t2->is_klassptr()->klass();
  // Verify that we understand the situation
  if( ((ciKlass*)superklass)->super_check_offset() != (juint)con2 )
    return NULL;                // Might be element-klass loading from array klass

  // If 'superklass' has no subklasses and is not an interface, then we are
  // assured that the only input which will pass the type check is
  // 'superklass' itself.
  //
  // We could be more liberal here, and allow the optimization on interfaces
  // which have a single implementor.  This would require us to increase the
  // expressiveness of the add_dependency() mechanism.

  // Object arrays must have their base element have no subtypes
  while( superklass->is_obj_array_klass() )
    superklass = superklass->as_obj_array_klass()->base_element_type();
  if( superklass->is_instance_klass() ) {
    ciInstanceKlass* ik = superklass->as_instance_klass();
    if( ik->has_subklass() || ik->flags().is_interface() ) return NULL;
    // Add a dependency if there is a chance that a subclass will be added later.
    if( !ik->flags().is_final()) {
      CompileLog* log = phase->C->log();
      if (log != NULL){
        log->elem("cast_up reason='!has_subklass' from='%d' to='(exact)'",
                  log->identify(ik));
      }
      phase->C->recorder()->add_dependent(ik, NULL);
    }
  }
  
  // Bypass the dependent load, and compare directly 
  this->set_req(1,ldk2);

  return this;
}

  CE_Eliminator(IR* hir) : _cee_count(0), _ifop_count(0), _hir(hir) {
    _has_substitution = false;
    _hir->iterate_preorder(this);
    if (_has_substitution) {
      // substituted some ifops/phis, so resolve the substitution
      SubstitutionResolver sr(_hir);
    }

    CompileLog* log = _hir->compilation()->log();
    if (log != NULL)
      log->set_context("optimize name='cee'");
  }

//------------------------------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, immutable_memory(), p, TypeInstPtr::KLASS) );
  // Get the array klass
  const TypeKlassPtr *tak = _gvn.type(array_klass)->is_klassptr();

  // array_klass's type is generally INexact array-of-oop.  Heroically
  // cast the array klass to EXACT array and uncommon-trap if the cast
  // fails.
  bool always_see_exact_class = false;
  if (MonomorphicArrayCheck
      && !too_many_traps(Deoptimization::Reason_array_check)) {
    always_see_exact_class = true;
    // (If no MDO at all, hope for the best, until a trap actually occurs.)
  }

  // Is the array klass is exactly its defined type?
  if (always_see_exact_class && !tak->klass_is_exact()) {
    // 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 (C) CmpPNode( array_klass, con ));
    Node* bol = _gvn.transform(new (C) 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);
  Node *a_e_klass = _gvn.transform( LoadKlassNode::make(_gvn, 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 );
}

 ~CE_Eliminator() {
   CompileLog* log = _hir->compilation()->log();
   if (log != NULL)
     log->clear_context(); // skip marker if nothing was printed
 }

JVMState* PredictedIntrinsicGenerator::generate(JVMState* jvms, Parse* parent_parser) {
  GraphKit kit(jvms);
  PhaseGVN& gvn = kit.gvn();

  CompileLog* log = kit.C->log();
  if (log != NULL) {
    log->elem("predicted_intrinsic bci='%d' method='%d'",
              jvms->bci(), log->identify(method()));
  }

  Node* slow_ctl = _intrinsic->generate_predicate(kit.sync_jvms());
  if (kit.failing())
    return NULL;  // might happen because of NodeCountInliningCutoff

  SafePointNode* slow_map = NULL;
  JVMState* slow_jvms;
  if (slow_ctl != NULL) {
    PreserveJVMState pjvms(&kit);
    kit.set_control(slow_ctl);
    if (!kit.stopped()) {
      slow_jvms = _cg->generate(kit.sync_jvms(), parent_parser);
      if (kit.failing())
        return NULL;  // might happen because of NodeCountInliningCutoff
      assert(slow_jvms != NULL, "must be");
      kit.add_exception_states_from(slow_jvms);
      kit.set_map(slow_jvms->map());
      if (!kit.stopped())
        slow_map = kit.stop();
    }
  }

  if (kit.stopped()) {
    // Predicate is always false.
    kit.set_jvms(slow_jvms);
    return kit.transfer_exceptions_into_jvms();
  }

  // Generate intrinsic code:
  JVMState* new_jvms = _intrinsic->generate(kit.sync_jvms(), parent_parser);
  if (new_jvms == NULL) {
    // Intrinsic failed, so use slow code or make a direct call.
    if (slow_map == NULL) {
      CallGenerator* cg = CallGenerator::for_direct_call(method());
      new_jvms = cg->generate(kit.sync_jvms(), parent_parser);
    } else {
      kit.set_jvms(slow_jvms);
      return kit.transfer_exceptions_into_jvms();
    }
  }
  kit.add_exception_states_from(new_jvms);
  kit.set_jvms(new_jvms);

  // Need to merge slow and fast?
  if (slow_map == NULL) {
    // The fast path is the only path remaining.
    return kit.transfer_exceptions_into_jvms();
  }

  if (kit.stopped()) {
    // Intrinsic method threw an exception, so it's just the slow path after all.
    kit.set_jvms(slow_jvms);
    return kit.transfer_exceptions_into_jvms();
  }

  // Finish the diamond.
  kit.C->set_has_split_ifs(true); // Has chance for split-if optimization
  RegionNode* region = new (kit.C) RegionNode(3);
  region->init_req(1, kit.control());
  region->init_req(2, slow_map->control());
  kit.set_control(gvn.transform(region));
  Node* iophi = PhiNode::make(region, kit.i_o(), Type::ABIO);
  iophi->set_req(2, slow_map->i_o());
  kit.set_i_o(gvn.transform(iophi));
  kit.merge_memory(slow_map->merged_memory(), region, 2);
  uint tos = kit.jvms()->stkoff() + kit.sp();
  uint limit = slow_map->req();
  for (uint i = TypeFunc::Parms; i < limit; i++) {
    // Skip unused stack slots; fast forward to monoff();
    if (i == tos) {
      i = kit.jvms()->monoff();
      if( i >= limit ) break;
    }
    Node* m = kit.map()->in(i);
    Node* n = slow_map->in(i);
    if (m != n) {
      const Type* t = gvn.type(m)->meet(gvn.type(n));
      Node* phi = PhiNode::make(region, m, t);
      phi->set_req(2, n);
      kit.map()->set_req(i, gvn.transform(phi));
    }
  }
  return kit.transfer_exceptions_into_jvms();
}

void LateInlineCallGenerator::do_late_inline() {
  // Can't inline it
  CallStaticJavaNode* call = call_node();
  if (call == NULL || call->outcnt() == 0 ||
      call->in(0) == NULL || call->in(0)->is_top()) {
    return;
  }

  const TypeTuple *r = call->tf()->domain();
  for (int i1 = 0; i1 < method()->arg_size(); i1++) {
    if (call->in(TypeFunc::Parms + i1)->is_top() && r->field_at(TypeFunc::Parms + i1) != Type::HALF) {
      assert(Compile::current()->inlining_incrementally(), "shouldn't happen during parsing");
      return;
    }
  }

  if (call->in(TypeFunc::Memory)->is_top()) {
    assert(Compile::current()->inlining_incrementally(), "shouldn't happen during parsing");
    return;
  }

  Compile* C = Compile::current();
  // Remove inlined methods from Compiler's lists.
  if (call->is_macro()) {
    C->remove_macro_node(call);
  }

  // Make a clone of the JVMState that appropriate to use for driving a parse
  JVMState* old_jvms = call->jvms();
  JVMState* jvms = old_jvms->clone_shallow(C);
  uint size = call->req();
  SafePointNode* map = new (C) SafePointNode(size, jvms);
  for (uint i1 = 0; i1 < size; i1++) {
    map->init_req(i1, call->in(i1));
  }

  // Make sure the state is a MergeMem for parsing.
  if (!map->in(TypeFunc::Memory)->is_MergeMem()) {
    Node* mem = MergeMemNode::make(C, map->in(TypeFunc::Memory));
    C->initial_gvn()->set_type_bottom(mem);
    map->set_req(TypeFunc::Memory, mem);
  }

  uint nargs = method()->arg_size();
  // blow away old call arguments
  Node* top = C->top();
  for (uint i1 = 0; i1 < nargs; i1++) {
    map->set_req(TypeFunc::Parms + i1, top);
  }
  jvms->set_map(map);

  // Make enough space in the expression stack to transfer
  // the incoming arguments and return value.
  map->ensure_stack(jvms, jvms->method()->max_stack());
  for (uint i1 = 0; i1 < nargs; i1++) {
    map->set_argument(jvms, i1, call->in(TypeFunc::Parms + i1));
  }

  // This check is done here because for_method_handle_inline() method
  // needs jvms for inlined state.
  if (!do_late_inline_check(jvms)) {
    map->disconnect_inputs(NULL, C);
    return;
  }

  C->print_inlining_insert(this);

  CompileLog* log = C->log();
  if (log != NULL) {
    log->head("late_inline method='%d'", log->identify(method()));
    JVMState* p = jvms;
    while (p != NULL) {
      log->elem("jvms bci='%d' method='%d'", p->bci(), log->identify(p->method()));
      p = p->caller();
    }
    log->tail("late_inline");
  }

  // Setup default node notes to be picked up by the inlining
  Node_Notes* old_nn = C->default_node_notes();
  if (old_nn != NULL) {
    Node_Notes* entry_nn = old_nn->clone(C);
    entry_nn->set_jvms(jvms);
    C->set_default_node_notes(entry_nn);
  }

  // Now perform the inling using the synthesized JVMState
  JVMState* new_jvms = _inline_cg->generate(jvms, NULL);
  if (new_jvms == NULL)  return;  // no change
  if (C->failing())      return;

  // Capture any exceptional control flow
  GraphKit kit(new_jvms);

  // Find the result object
  Node* result = C->top();
  int   result_size = method()->return_type()->size();
  if (result_size != 0 && !kit.stopped()) {
    result = (result_size == 1) ? kit.pop() : kit.pop_pair();
  }
//.........这里部分代码省略.........

JVMState* PredicatedIntrinsicGenerator::generate(JVMState* jvms) {
  // The code we want to generate here is:
  //    if (receiver == NULL)
  //        uncommon_Trap
  //    if (predicate(0))
  //        do_intrinsic(0)
  //    else
  //    if (predicate(1))
  //        do_intrinsic(1)
  //    ...
  //    else
  //        do_java_comp

  GraphKit kit(jvms);
  PhaseGVN& gvn = kit.gvn();

  CompileLog* log = kit.C->log();
  if (log != NULL) {
    log->elem("predicated_intrinsic bci='%d' method='%d'",
              jvms->bci(), log->identify(method()));
  }

  if (!method()->is_static()) {
    // We need an explicit receiver null_check before checking its type in predicate.
    // We share a map with the caller, so his JVMS gets adjusted.
    Node* receiver = kit.null_check_receiver_before_call(method());
    if (kit.stopped()) {
      return kit.transfer_exceptions_into_jvms();
    }
  }

  int n_predicates = _intrinsic->predicates_count();
  assert(n_predicates > 0, "sanity");

  JVMState** result_jvms = NEW_RESOURCE_ARRAY(JVMState*, (n_predicates+1));

  // Region for normal compilation code if intrinsic failed.
  Node* slow_region = new (kit.C) RegionNode(1);

  int results = 0;
  for (int predicate = 0; (predicate < n_predicates) && !kit.stopped(); predicate++) {
#ifdef ASSERT
    JVMState* old_jvms = kit.jvms();
    SafePointNode* old_map = kit.map();
    Node* old_io  = old_map->i_o();
    Node* old_mem = old_map->memory();
    Node* old_exc = old_map->next_exception();
#endif
    Node* else_ctrl = _intrinsic->generate_predicate(kit.sync_jvms(), predicate);
#ifdef ASSERT
    // Assert(no_new_memory && no_new_io && no_new_exceptions) after generate_predicate.
    assert(old_jvms == kit.jvms(), "generate_predicate should not change jvm state");
    SafePointNode* new_map = kit.map();
    assert(old_io  == new_map->i_o(), "generate_predicate should not change i_o");
    assert(old_mem == new_map->memory(), "generate_predicate should not change memory");
    assert(old_exc == new_map->next_exception(), "generate_predicate should not add exceptions");
#endif
    if (!kit.stopped()) {
      PreserveJVMState pjvms(&kit);
      // Generate intrinsic code:
      JVMState* new_jvms = _intrinsic->generate(kit.sync_jvms());
      if (new_jvms == NULL) {
        // Intrinsic failed, use normal compilation path for this predicate.
        slow_region->add_req(kit.control());
      } else {
        kit.add_exception_states_from(new_jvms);
        kit.set_jvms(new_jvms);
        if (!kit.stopped()) {
          result_jvms[results++] = kit.jvms();
        }
      }
    }
    if (else_ctrl == NULL) {
      else_ctrl = kit.C->top();
    }
    kit.set_control(else_ctrl);
  }
  if (!kit.stopped()) {
    // Final 'else' after predicates.
    slow_region->add_req(kit.control());
  }
  if (slow_region->req() > 1) {
    PreserveJVMState pjvms(&kit);
    // Generate normal compilation code:
    kit.set_control(gvn.transform(slow_region));
    JVMState* new_jvms = _cg->generate(kit.sync_jvms());
    if (kit.failing())
      return NULL;  // might happen because of NodeCountInliningCutoff
    assert(new_jvms != NULL, "must be");
    kit.add_exception_states_from(new_jvms);
    kit.set_jvms(new_jvms);
    if (!kit.stopped()) {
      result_jvms[results++] = kit.jvms();
    }
  }

  if (results == 0) {
    // All paths ended in uncommon traps.
    (void) kit.stop();
    return kit.transfer_exceptions_into_jvms();
//.........这里部分代码省略.........

JVMState* PredictedDynamicCallGenerator::generate(JVMState* jvms) {
  GraphKit kit(jvms);
  Compile* C = kit.C;
  PhaseGVN& gvn = kit.gvn();

  CompileLog* log = C->log();
  if (log != NULL) {
    log->elem("predicted_dynamic_call bci='%d'", jvms->bci());
  }

  const TypeOopPtr* predicted_mh_ptr = TypeOopPtr::make_from_constant(_predicted_method_handle, true);
  Node* predicted_mh = kit.makecon(predicted_mh_ptr);

  Node* bol = NULL;
  int bc = jvms->method()->java_code_at_bci(jvms->bci());
  if (bc != Bytecodes::_invokedynamic) {
    // This is the selectAlternative idiom for guardWithTest or
    // similar idioms.
    Node* receiver = kit.argument(0);

    // Check if the MethodHandle is the expected one
    Node* cmp = gvn.transform(new (C, 3) CmpPNode(receiver, predicted_mh));
    bol = gvn.transform(new (C, 2) BoolNode(cmp, BoolTest::eq) );
  } else {
    // Get the constant pool cache from the caller class.
    ciMethod* caller_method = jvms->method();
    ciBytecodeStream str(caller_method);
    str.force_bci(jvms->bci());  // Set the stream to the invokedynamic bci.
    ciCPCache* cpcache = str.get_cpcache();

    // Get the offset of the CallSite from the constant pool cache
    // pointer.
    int index = str.get_method_index();
    size_t call_site_offset = cpcache->get_f1_offset(index);

    // Load the CallSite object from the constant pool cache.
    const TypeOopPtr* cpcache_type   = TypeOopPtr::make_from_constant(cpcache);  // returns TypeAryPtr of type T_OBJECT
    const TypeOopPtr* call_site_type = TypeOopPtr::make_from_klass(C->env()->CallSite_klass());
    Node* cpcache_adr   = kit.makecon(cpcache_type);
    Node* call_site_adr = kit.basic_plus_adr(cpcache_adr, call_site_offset);
    // The oops in the constant pool cache are not compressed; load then as raw pointers.
    Node* call_site     = kit.make_load(kit.control(), call_site_adr, call_site_type, T_ADDRESS, Compile::AliasIdxRaw);

    // Load the target MethodHandle from the CallSite object.
    const TypeOopPtr* target_type = TypeOopPtr::make_from_klass(C->env()->MethodHandle_klass());
    Node* target_adr = kit.basic_plus_adr(call_site, call_site, java_lang_invoke_CallSite::target_offset_in_bytes());
    Node* target_mh  = kit.make_load(kit.control(), target_adr, target_type, T_OBJECT);

    // Check if the MethodHandle is still the same.
    Node* cmp = gvn.transform(new (C, 3) CmpPNode(target_mh, predicted_mh));
    bol = gvn.transform(new (C, 2) BoolNode(cmp, BoolTest::eq) );
  }
  IfNode* iff = kit.create_and_xform_if(kit.control(), bol, _hit_prob, COUNT_UNKNOWN);
  kit.set_control( gvn.transform(new (C, 1) IfTrueNode (iff)));
  Node* slow_ctl = gvn.transform(new (C, 1) IfFalseNode(iff));

  SafePointNode* slow_map = NULL;
  JVMState* slow_jvms;
  { PreserveJVMState pjvms(&kit);
    kit.set_control(slow_ctl);
    if (!kit.stopped()) {
      slow_jvms = _if_missed->generate(kit.sync_jvms());
      if (kit.failing())
        return NULL;  // might happen because of NodeCountInliningCutoff
      assert(slow_jvms != NULL, "must be");
      kit.add_exception_states_from(slow_jvms);
      kit.set_map(slow_jvms->map());
      if (!kit.stopped())
        slow_map = kit.stop();
    }
  }

  if (kit.stopped()) {
    // Instance exactly does not matches the desired type.
    kit.set_jvms(slow_jvms);
    return kit.transfer_exceptions_into_jvms();
  }

  // Make the hot call:
  JVMState* new_jvms = _if_hit->generate(kit.sync_jvms());
  if (new_jvms == NULL) {
    // Inline failed, so make a direct call.
    assert(_if_hit->is_inline(), "must have been a failed inline");
    CallGenerator* cg = CallGenerator::for_direct_call(_if_hit->method());
    new_jvms = cg->generate(kit.sync_jvms());
  }
  kit.add_exception_states_from(new_jvms);
  kit.set_jvms(new_jvms);

  // Need to merge slow and fast?
  if (slow_map == NULL) {
    // The fast path is the only path remaining.
    return kit.transfer_exceptions_into_jvms();
  }

  if (kit.stopped()) {
    // Inlined method threw an exception, so it's just the slow path after all.
    kit.set_jvms(slow_jvms);
    return kit.transfer_exceptions_into_jvms();
  }
//.........这里部分代码省略.........

void LateInlineCallGenerator::do_late_inline() {
  // Can't inline it
  if (call_node() == NULL || call_node()->outcnt() == 0 ||
      call_node()->in(0) == NULL || call_node()->in(0)->is_top())
    return;

  CallStaticJavaNode* call = call_node();

  // Make a clone of the JVMState that appropriate to use for driving a parse
  Compile* C = Compile::current();
  JVMState* jvms     = call->jvms()->clone_shallow(C);
  uint size = call->req();
  SafePointNode* map = new (C, size) SafePointNode(size, jvms);
  for (uint i1 = 0; i1 < size; i1++) {
    map->init_req(i1, call->in(i1));
  }

  // Make sure the state is a MergeMem for parsing.
  if (!map->in(TypeFunc::Memory)->is_MergeMem()) {
    map->set_req(TypeFunc::Memory, MergeMemNode::make(C, map->in(TypeFunc::Memory)));
  }

  // Make enough space for the expression stack and transfer the incoming arguments
  int nargs    = method()->arg_size();
  jvms->set_map(map);
  map->ensure_stack(jvms, jvms->method()->max_stack());
  if (nargs > 0) {
    for (int i1 = 0; i1 < nargs; i1++) {
      map->set_req(i1 + jvms->argoff(), call->in(TypeFunc::Parms + i1));
    }
  }

  CompileLog* log = C->log();
  if (log != NULL) {
    log->head("late_inline method='%d'", log->identify(method()));
    JVMState* p = jvms;
    while (p != NULL) {
      log->elem("jvms bci='%d' method='%d'", p->bci(), log->identify(p->method()));
      p = p->caller();
    }
    log->tail("late_inline");
  }

  // Setup default node notes to be picked up by the inlining
  Node_Notes* old_nn = C->default_node_notes();
  if (old_nn != NULL) {
    Node_Notes* entry_nn = old_nn->clone(C);
    entry_nn->set_jvms(jvms);
    C->set_default_node_notes(entry_nn);
  }

  // Now perform the inling using the synthesized JVMState
  JVMState* new_jvms = _inline_cg->generate(jvms);
  if (new_jvms == NULL)  return;  // no change
  if (C->failing())      return;

  // Capture any exceptional control flow
  GraphKit kit(new_jvms);

  // Find the result object
  Node* result = C->top();
  int   result_size = method()->return_type()->size();
  if (result_size != 0 && !kit.stopped()) {
    result = (result_size == 1) ? kit.pop() : kit.pop_pair();
  }

  kit.replace_call(call, result);
}

//------------------------------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 Compilation::build_hir() {
  CHECK_BAILOUT();

  // setup ir
  CompileLog* log = this->log();
  if (log != NULL) {
    log->begin_head("parse method='%d' ",
                    log->identify(_method));
    log->stamp();
    log->end_head();
  }
  _hir = new IR(this, method(), osr_bci());
  if (log)  log->done("parse");
  if (!_hir->is_valid()) {
    bailout("invalid parsing");
    return;
  }

#ifndef PRODUCT
  if (PrintCFGToFile) {
    CFGPrinter::print_cfg(_hir, "After Generation of HIR", true, false);
  }
#endif

#ifndef PRODUCT
  if (PrintCFG || PrintCFG0) { tty->print_cr("CFG after parsing"); _hir->print(true); }
  if (PrintIR  || PrintIR0 ) { tty->print_cr("IR after parsing"); _hir->print(false); }
#endif

  _hir->verify();

  if (UseC1Optimizations) {
    NEEDS_CLEANUP
    // optimization
    PhaseTraceTime timeit(_t_optimize_blocks);

    _hir->optimize_blocks();
  }

  _hir->verify();

  _hir->split_critical_edges();

#ifndef PRODUCT
  if (PrintCFG || PrintCFG1) { tty->print_cr("CFG after optimizations"); _hir->print(true); }
  if (PrintIR  || PrintIR1 ) { tty->print_cr("IR after optimizations"); _hir->print(false); }
#endif

  _hir->verify();

  // compute block ordering for code generation
  // the control flow must not be changed from here on
  _hir->compute_code();

  if (UseGlobalValueNumbering) {
    // No resource mark here! LoopInvariantCodeMotion can allocate ValueStack objects.
    int instructions = Instruction::number_of_instructions();
    GlobalValueNumbering gvn(_hir);
    assert(instructions == Instruction::number_of_instructions(),
           "shouldn't have created an instructions");
  }

  _hir->verify();

#ifndef PRODUCT
  if (PrintCFGToFile) {
    CFGPrinter::print_cfg(_hir, "Before RangeCheckElimination", true, false);
  }
#endif

  if (RangeCheckElimination) {
    if (_hir->osr_entry() == NULL) {
      PhaseTraceTime timeit(_t_rangeCheckElimination);
      RangeCheckElimination::eliminate(_hir);
    }
  }

#ifndef PRODUCT
  if (PrintCFGToFile) {
    CFGPrinter::print_cfg(_hir, "After RangeCheckElimination", true, false);
  }
#endif

  if (UseC1Optimizations) {
    // loop invariant code motion reorders instructions and range
    // check elimination adds new instructions so do null check
    // elimination after.
    NEEDS_CLEANUP
    // optimization
    PhaseTraceTime timeit(_t_optimize_null_checks);

    _hir->eliminate_null_checks();
  }

  _hir->verify();

  // compute use counts after global value numbering
  _hir->compute_use_counts();

#ifndef PRODUCT
//.........这里部分代码省略.........

  PhaseTraceTime(TimerName timer)
  : TraceTime("", &timers[timer], CITime || CITimeEach, Verbose), _log(NULL) {
    if (Compilation::current() != NULL) {
      _log = Compilation::current()->log();
    }

    if (_log != NULL) {
      _log->begin_head("phase name='%s'", timer_name[timer]);
      _log->stamp();
      _log->end_head();
    }
  }

 ~PhaseTraceTime() {
   if (_log != NULL)
     _log->done("phase");
 }