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 /*

  * Copyright (c) 1998, 2012, 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 "ci/ciCallSite.hpp"

 #include "ci/ciMethodHandle.hpp"

 #include "classfile/vmSymbols.hpp"

 #include "compiler/compileBroker.hpp"

 #include "compiler/compileLog.hpp"

 #include "interpreter/linkResolver.hpp"

 #include "opto/addnode.hpp"

 #include "opto/callGenerator.hpp"

 #include "opto/cfgnode.hpp"

 #include "opto/mulnode.hpp"

 #include "opto/parse.hpp"

 #include "opto/rootnode.hpp"

 #include "opto/runtime.hpp"

 #include "opto/subnode.hpp"

 #include "prims/nativeLookup.hpp"

 #include "runtime/sharedRuntime.hpp"

 void trace_type_profile(Compile* C, ciMethod *method, int depth, int bci, ciMethod *prof_method, ciKlass *prof_klass, int site_count, int receiver_count) {

   if (TraceTypeProfile || PrintInlining NOT_PRODUCT(|| PrintOptoInlining)) {

     outputStream* out = tty;

     if (!PrintInlining) {

       if (NOT_PRODUCT(!PrintOpto &&) !PrintCompilation) {

         method->print_short_name();

         tty->cr();

       }

       CompileTask::print_inlining(prof_method, depth, bci);

     } else {

       out = C->print_inlining_stream();

     }

     CompileTask::print_inline_indent(depth, out);

     out->print(" \\-> TypeProfile (%d/%d counts) = ", receiver_count, site_count);

     stringStream ss;

     prof_klass->name()->print_symbol_on(&ss);

     out->print(ss.as_string());

     out->cr();

   }

 }

 CallGenerator* Compile::call_generator(ciMethod* callee, int vtable_index, bool call_does_dispatch,

                                        JVMState* jvms, bool allow_inline,

                                        float prof_factor, bool allow_intrinsics, bool delayed_forbidden) {

   ciMethod*       caller   = jvms->method();

   int             bci      = jvms->bci();

   Bytecodes::Code bytecode = caller->java_code_at_bci(bci);

   guarantee(callee != NULL, "failed method resolution");

   // Dtrace currently doesn't work unless all calls are vanilla

   if (env()->dtrace_method_probes()) {

     allow_inline = false;

   }

   // Note: When we get profiling during stage-1 compiles, we want to pull

   // from more specific profile data which pertains to this inlining.

   // Right now, ignore the information in jvms->caller(), and do method[bci].

   ciCallProfile profile = caller->call_profile_at_bci(bci);

   // See how many times this site has been invoked.

   int site_count = profile.count();

   int receiver_count = -1;

   if (call_does_dispatch && UseTypeProfile && profile.has_receiver(0)) {

     // Receivers in the profile structure are ordered by call counts

     // so that the most called (major) receiver is profile.receiver(0).

     receiver_count = profile.receiver_count(0);

   }

   CompileLog* log = this->log();

   if (log != NULL) {

     int rid = (receiver_count >= 0)? log->identify(profile.receiver(0)): -1;

     int r2id = (rid != -1 && profile.has_receiver(1))? log->identify(profile.receiver(1)):-1;

     log->begin_elem("call method='%d' count='%d' prof_factor='%g'",

                     log->identify(callee), site_count, prof_factor);

     if (call_does_dispatch)  log->print(" virtual='1'");

     if (allow_inline)     log->print(" inline='1'");

     if (receiver_count >= 0) {

       log->print(" receiver='%d' receiver_count='%d'", rid, receiver_count);

       if (profile.has_receiver(1)) {

         log->print(" receiver2='%d' receiver2_count='%d'", r2id, profile.receiver_count(1));

       }

     }

     log->end_elem();

   }

   // Special case the handling of certain common, profitable library

   // methods.  If these methods are replaced with specialized code,

   // then we return it as the inlined version of the call.

   // We do this before the strict f.p. check below because the

   // intrinsics handle strict f.p. correctly.

   if (allow_inline && allow_intrinsics) {

     CallGenerator* cg = find_intrinsic(callee, call_does_dispatch);

     if (cg != NULL) {

       if (cg->is_predicted()) {

         // Code without intrinsic but, hopefully, inlined.

         CallGenerator* inline_cg = this->call_generator(callee,

               vtable_index, call_does_dispatch, jvms, allow_inline, prof_factor, false);

         if (inline_cg != NULL) {

           cg = CallGenerator::for_predicted_intrinsic(cg, inline_cg);

         }

       }

       return cg;

     }

   }

   // Do method handle calls.

   // NOTE: This must happen before normal inlining logic below since

   // MethodHandle.invoke* are native methods which obviously don't

   // have bytecodes and so normal inlining fails.

   if (callee->is_method_handle_intrinsic()) {

     CallGenerator* cg = CallGenerator::for_method_handle_call(jvms, caller, callee, delayed_forbidden);

     assert(cg == NULL || !delayed_forbidden || !cg->is_late_inline() || cg->is_mh_late_inline(), "unexpected CallGenerator");

     return cg;

   }

   // Do not inline strict fp into non-strict code, or the reverse

   if (caller->is_strict() ^ callee->is_strict()) {

     allow_inline = false;

   }

   // Attempt to inline...

   if (allow_inline) {

     // The profile data is only partly attributable to this caller,

     // scale back the call site information.

     float past_uses = jvms->method()->scale_count(site_count, prof_factor);

     // This is the number of times we expect the call code to be used.

     float expected_uses = past_uses;

     // Try inlining a bytecoded method:

     if (!call_does_dispatch) {

       InlineTree* ilt;

       if (UseOldInlining) {

         ilt = InlineTree::find_subtree_from_root(this->ilt(), jvms->caller(), jvms->method());

       } else {

         // Make a disembodied, stateless ILT.

         // TO DO:  When UseOldInlining is removed, copy the ILT code elsewhere.

         float site_invoke_ratio = prof_factor;

         // Note:  ilt is for the root of this parse, not the present call site.

         ilt = new InlineTree(this, jvms->method(), jvms->caller(), site_invoke_ratio, MaxInlineLevel);

       }

       WarmCallInfo scratch_ci;

       if (!UseOldInlining)

         scratch_ci.init(jvms, callee, profile, prof_factor);

       bool should_delay = false;

       WarmCallInfo* ci = ilt->ok_to_inline(callee, jvms, profile, &scratch_ci, should_delay);

       assert(ci != &scratch_ci, "do not let this pointer escape");

       bool allow_inline   = (ci != NULL && !ci->is_cold());

       bool require_inline = (allow_inline && ci->is_hot());

       if (allow_inline) {

         CallGenerator* cg = CallGenerator::for_inline(callee, expected_uses);

         if (require_inline && cg != NULL) {

           // Delay the inlining of this method to give us the

           // opportunity to perform some high level optimizations

           // first.

           if (should_delay_string_inlining(callee, jvms)) {

             assert(!delayed_forbidden, "strange");

             return CallGenerator::for_string_late_inline(callee, cg);

           } else if (should_delay_boxing_inlining(callee, jvms)) {

             assert(!delayed_forbidden, "strange");

             return CallGenerator::for_boxing_late_inline(callee, cg);

           } else if ((should_delay || AlwaysIncrementalInline) && !delayed_forbidden) {

             return CallGenerator::for_late_inline(callee, cg);

           }

         }

         if (cg == NULL || should_delay) {

           // Fall through.

         } else if (require_inline || !InlineWarmCalls) {

           return cg;

         } else {

           CallGenerator* cold_cg = call_generator(callee, vtable_index, call_does_dispatch, jvms, false, prof_factor);

           return CallGenerator::for_warm_call(ci, cold_cg, cg);

         }

       }

     }

     // Try using the type profile.

     if (call_does_dispatch && site_count > 0 && receiver_count > 0) {

       // The major receiver's count >= TypeProfileMajorReceiverPercent of site_count.

       bool have_major_receiver = (100.*profile.receiver_prob(0) >= (float)TypeProfileMajorReceiverPercent);

       ciMethod* receiver_method = NULL;

       if (have_major_receiver || profile.morphism() == 1 ||

           (profile.morphism() == 2 && UseBimorphicInlining)) {

         // receiver_method = profile.method();

         // Profiles do not suggest methods now.  Look it up in the major receiver.

         receiver_method = callee->resolve_invoke(jvms->method()->holder(),

                                                       profile.receiver(0));

       }

       if (receiver_method != NULL) {

         // The single majority receiver sufficiently outweighs the minority.

         CallGenerator* hit_cg = this->call_generator(receiver_method,

               vtable_index, !call_does_dispatch, jvms, allow_inline, prof_factor);

         if (hit_cg != NULL) {

           // Look up second receiver.

           CallGenerator* next_hit_cg = NULL;

           ciMethod* next_receiver_method = NULL;

           if (profile.morphism() == 2 && UseBimorphicInlining) {

             next_receiver_method = callee->resolve_invoke(jvms->method()->holder(),

                                                                profile.receiver(1));

             if (next_receiver_method != NULL) {

               next_hit_cg = this->call_generator(next_receiver_method,

                                   vtable_index, !call_does_dispatch, jvms,

                                   allow_inline, prof_factor);

               if (next_hit_cg != NULL && !next_hit_cg->is_inline() &&

                   have_major_receiver && UseOnlyInlinedBimorphic) {

                   // Skip if we can't inline second receiver's method

                   next_hit_cg = NULL;

               }

             }

           }

           CallGenerator* miss_cg;

           Deoptimization::DeoptReason reason = (profile.morphism() == 2) ?

                                     Deoptimization::Reason_bimorphic :

                                     Deoptimization::Reason_class_check;

           if (( profile.morphism() == 1 ||

                (profile.morphism() == 2 && next_hit_cg != NULL) ) &&

               !too_many_traps(jvms->method(), jvms->bci(), reason)

              ) {

             // Generate uncommon trap for class check failure path

             // in case of monomorphic or bimorphic virtual call site.

             miss_cg = CallGenerator::for_uncommon_trap(callee, reason,

                         Deoptimization::Action_maybe_recompile);

           } else {

             // Generate virtual call for class check failure path

             // in case of polymorphic virtual call site.

             miss_cg = CallGenerator::for_virtual_call(callee, vtable_index);

           }

           if (miss_cg != NULL) {

             if (next_hit_cg != NULL) {

               trace_type_profile(C, jvms->method(), jvms->depth() - 1, jvms->bci(), next_receiver_method, profile.receiver(1), site_count, profile.receiver_count(1));

               // We don't need to record dependency on a receiver here and below.

               // Whenever we inline, the dependency is added by Parse::Parse().

               miss_cg = CallGenerator::for_predicted_call(profile.receiver(1), miss_cg, next_hit_cg, PROB_MAX);

             }

             if (miss_cg != NULL) {

               trace_type_profile(C, jvms->method(), jvms->depth() - 1, jvms->bci(), receiver_method, profile.receiver(0), site_count, receiver_count);

               CallGenerator* cg = CallGenerator::for_predicted_call(profile.receiver(0), miss_cg, hit_cg, profile.receiver_prob(0));

               if (cg != NULL)  return cg;

             }

           }

         }

       }

     }

   }

   // There was no special inlining tactic, or it bailed out.

   // Use a more generic tactic, like a simple call.

   if (call_does_dispatch) {

     return CallGenerator::for_virtual_call(callee, vtable_index);

   } else {

     // Class Hierarchy Analysis or Type Profile reveals a unique target,

     // or it is a static or special call.

     return CallGenerator::for_direct_call(callee, should_delay_inlining(callee, jvms));

   }

 }

 // Return true for methods that shouldn't be inlined early so that

 // they are easier to analyze and optimize as intrinsics.

 bool Compile::should_delay_string_inlining(ciMethod* call_method, JVMState* jvms) {

   if (has_stringbuilder()) {

     if ((call_method->holder() == C->env()->StringBuilder_klass() ||

          call_method->holder() == C->env()->StringBuffer_klass()) &&

         (jvms->method()->holder() == C->env()->StringBuilder_klass() ||

          jvms->method()->holder() == C->env()->StringBuffer_klass())) {

       // Delay SB calls only when called from non-SB code

       return false;

     }

     switch (call_method->intrinsic_id()) {

       case vmIntrinsics::_StringBuilder_void:

       case vmIntrinsics::_StringBuilder_int:

       case vmIntrinsics::_StringBuilder_String:

       case vmIntrinsics::_StringBuilder_append_char:

       case vmIntrinsics::_StringBuilder_append_int:

       case vmIntrinsics::_StringBuilder_append_String:

       case vmIntrinsics::_StringBuilder_toString:

       case vmIntrinsics::_StringBuffer_void:

       case vmIntrinsics::_StringBuffer_int:

       case vmIntrinsics::_StringBuffer_String:

       case vmIntrinsics::_StringBuffer_append_char:

       case vmIntrinsics::_StringBuffer_append_int:

       case vmIntrinsics::_StringBuffer_append_String:

       case vmIntrinsics::_StringBuffer_toString:

       case vmIntrinsics::_Integer_toString:

         return true;

       case vmIntrinsics::_String_String:

         {

           Node* receiver = jvms->map()->in(jvms->argoff() + 1);

           if (receiver->is_Proj() && receiver->in(0)->is_CallStaticJava()) {

             CallStaticJavaNode* csj = receiver->in(0)->as_CallStaticJava();

             ciMethod* m = csj->method();

             if (m != NULL &&

                 (m->intrinsic_id() == vmIntrinsics::_StringBuffer_toString ||

                  m->intrinsic_id() == vmIntrinsics::_StringBuilder_toString))

               // Delay String.<init>(new SB())

               return true;

           }

           return false;

         }

       default:

         return false;

     }

   }

   return false;

 }

 bool Compile::should_delay_boxing_inlining(ciMethod* call_method, JVMState* jvms) {

   if (eliminate_boxing() && call_method->is_boxing_method()) {

     set_has_boxed_value(true);

     return true;

   }

   return false;

 }

 // uncommon-trap call-sites where callee is unloaded, uninitialized or will not link

 bool Parse::can_not_compile_call_site(ciMethod *dest_method, ciInstanceKlass* klass) {

   // Additional inputs to consider...

   // bc      = bc()

   // caller  = method()

   // iter().get_method_holder_index()

   assert( dest_method->is_loaded(), "ciTypeFlow should not let us get here" );

   // Interface classes can be loaded & linked and never get around to

   // being initialized.  Uncommon-trap for not-initialized static or

   // v-calls.  Let interface calls happen.

   ciInstanceKlass* holder_klass = dest_method->holder();

   if (!holder_klass->is_being_initialized() &&

       !holder_klass->is_initialized() &&

       !holder_klass->is_interface()) {

     uncommon_trap(Deoptimization::Reason_uninitialized,

                   Deoptimization::Action_reinterpret,

                   holder_klass);

     return true;

   }

   assert(dest_method->is_loaded(), "dest_method: typeflow responsibility");

   return false;

 }

 //------------------------------do_call----------------------------------------

 // Handle your basic call.  Inline if we can & want to, else just setup call.

 void Parse::do_call() {

   // It's likely we are going to add debug info soon.

   // Also, if we inline a guy who eventually needs debug info for this JVMS,

   // our contribution to it is cleaned up right here.

   kill_dead_locals();

   // Set frequently used booleans

   const bool is_virtual = bc() == Bytecodes::_invokevirtual;

   const bool is_virtual_or_interface = is_virtual || bc() == Bytecodes::_invokeinterface;

   const bool has_receiver = Bytecodes::has_receiver(bc());

   // Find target being called

   bool             will_link;

   ciSignature*     declared_signature = NULL;

   ciMethod*        orig_callee  = iter().get_method(will_link, &declared_signature);  // callee in the bytecode

   ciInstanceKlass* holder_klass = orig_callee->holder();

   ciKlass*         holder       = iter().get_declared_method_holder();

   ciInstanceKlass* klass = ciEnv::get_instance_klass_for_declared_method_holder(holder);

   assert(declared_signature != NULL, "cannot be null");

   // uncommon-trap when callee is unloaded, uninitialized or will not link

   // bailout when too many arguments for register representation

   if (!will_link || can_not_compile_call_site(orig_callee, klass)) {

 #ifndef PRODUCT

     if (PrintOpto && (Verbose || WizardMode)) {

       method()->print_name(); tty->print_cr(" can not compile call at bci %d to:", bci());

       orig_callee->print_name(); tty->cr();

     }

 #endif

     return;

   }

   assert(holder_klass->is_loaded(), "");

   //assert((bc_callee->is_static() || is_invokedynamic) == !has_receiver , "must match bc");  // XXX invokehandle (cur_bc_raw)

   // Note: this takes into account invokeinterface of methods declared in java/lang/Object,

   // which should be invokevirtuals but according to the VM spec may be invokeinterfaces

   assert(holder_klass->is_interface() || holder_klass->super() == NULL || (bc() != Bytecodes::_invokeinterface), "must match bc");

   // Note:  In the absence of miranda methods, an abstract class K can perform

   // an invokevirtual directly on an interface method I.m if K implements I.

   // orig_callee is the resolved callee which's signature includes the

   // appendix argument.

   const int nargs = orig_callee->arg_size();

   const bool is_signature_polymorphic = MethodHandles::is_signature_polymorphic(orig_callee->intrinsic_id());

   // Push appendix argument (MethodType, CallSite, etc.), if one.

   if (iter().has_appendix()) {

     ciObject* appendix_arg = iter().get_appendix();

     const TypeOopPtr* appendix_arg_type = TypeOopPtr::make_from_constant(appendix_arg);

     Node* appendix_arg_node = _gvn.makecon(appendix_arg_type);

     push(appendix_arg_node);

   }

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

   // Does Class Hierarchy Analysis reveal only a single target of a v-call?

   // Then we may inline or make a static call, but become dependent on there being only 1 target.

   // Does the call-site type profile reveal only one receiver?

   // Then we may introduce a run-time check and inline on the path where it succeeds.

   // The other path may uncommon_trap, check for another receiver, or do a v-call.

   // Try to get the most accurate receiver type

   ciMethod* callee             = orig_callee;

   int       vtable_index       = Method::invalid_vtable_index;

   bool      call_does_dispatch = false;

   if (is_virtual_or_interface) {

     Node*             receiver_node = stack(sp() - nargs);

     const TypeOopPtr* receiver_type = _gvn.type(receiver_node)->isa_oopptr();

     // call_does_dispatch and vtable_index are out-parameters.  They might be changed.

     callee = C->optimize_virtual_call(method(), bci(), klass, orig_callee, receiver_type,

                                       is_virtual,

                                       call_does_dispatch, vtable_index);  // out-parameters

   }

   // Note:  It's OK to try to inline a virtual call.

   // The call generator will not attempt to inline a polymorphic call

   // unless it knows how to optimize the receiver dispatch.

   bool try_inline = (C->do_inlining() || InlineAccessors);

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

   dec_sp(nargs);              // Temporarily pop args for JVM state of call

   JVMState* jvms = sync_jvms();

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

   // Decide call tactic.

   // This call checks with CHA, the interpreter profile, intrinsics table, etc.

   // It decides whether inlining is desirable or not.

   CallGenerator* cg = C->call_generator(callee, vtable_index, call_does_dispatch, jvms, try_inline, prof_factor());

   // NOTE:  Don't use orig_callee and callee after this point!  Use cg->method() instead.

   orig_callee = callee = NULL;

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

   // Round double arguments before call

   round_double_arguments(cg->method());

 #ifndef PRODUCT

   // bump global counters for calls

   count_compiled_calls(/*at_method_entry*/ false, cg->is_inline());

   // Record first part of parsing work for this call

   parse_histogram()->record_change();

 #endif // not PRODUCT

   assert(jvms == this->jvms(), "still operating on the right JVMS");

   assert(jvms_in_sync(),       "jvms must carry full info into CG");

   // save across call, for a subsequent cast_not_null.

   Node* receiver = has_receiver ? argument(0) : NULL;

   // Bump method data counters (We profile *before* the call is made

   // because exceptions don't return to the call site.)

   profile_call(receiver);

   JVMState* new_jvms = cg->generate(jvms);

   if (new_jvms == NULL) {

     // When inlining attempt fails (e.g., too many arguments),

     // it may contaminate the current compile state, making it

     // impossible to pull back and try again.  Once we call

     // cg->generate(), we are committed.  If it fails, the whole

     // compilation task is compromised.

     if (failing())  return;

     // This can happen if a library intrinsic is available, but refuses

     // the call site, perhaps because it did not match a pattern the

     // intrinsic was expecting to optimize. Should always be possible to

     // get a normal java call that may inline in that case

     cg = C->call_generator(cg->method(), vtable_index, call_does_dispatch, jvms, try_inline, prof_factor(), /* allow_intrinsics= */ false);

     if ((new_jvms = cg->generate(jvms)) == NULL) {

       guarantee(failing(), "call failed to generate:  calls should work");

       return;

     }

   }

   if (cg->is_inline()) {

     // Accumulate has_loops estimate

     C->set_has_loops(C->has_loops() || cg->method()->has_loops());

     C->env()->notice_inlined_method(cg->method());

   }

   // Reset parser state from [new_]jvms, which now carries results of the call.

   // Return value (if any) is already pushed on the stack by the cg.

   add_exception_states_from(new_jvms);

   if (new_jvms->map()->control() == top()) {

     stop_and_kill_map();

   } else {

     assert(new_jvms->same_calls_as(jvms), "method/bci left unchanged");

     set_jvms(new_jvms);

   }

   if (!stopped()) {

     // This was some sort of virtual call, which did a null check for us.

     // Now we can assert receiver-not-null, on the normal return path.

     if (receiver != NULL && cg->is_virtual()) {

       Node* cast = cast_not_null(receiver);

       // %%% assert(receiver == cast, "should already have cast the receiver");

     }

     // Round double result after a call from strict to non-strict code

     round_double_result(cg->method());

     ciType* rtype = cg->method()->return_type();

     ciType* ctype = declared_signature->return_type();

     if (Bytecodes::has_optional_appendix(iter().cur_bc_raw()) || is_signature_polymorphic) {

       // Be careful here with return types.

       if (ctype != rtype) {

         BasicType rt = rtype->basic_type();

         BasicType ct = ctype->basic_type();

         if (ct == T_VOID) {

           // It's OK for a method  to return a value that is discarded.

           // The discarding does not require any special action from the caller.

           // The Java code knows this, at VerifyType.isNullConversion.

           pop_node(rt);  // whatever it was, pop it

         } else if (rt == T_INT || is_subword_type(rt)) {

           // Nothing.  These cases are handled in lambda form bytecode.

           assert(ct == T_INT || is_subword_type(ct), err_msg_res("must match: rt=%s, ct=%s", type2name(rt), type2name(ct)));

         } else if (rt == T_OBJECT || rt == T_ARRAY) {

           assert(ct == T_OBJECT || ct == T_ARRAY, err_msg_res("rt=%s, ct=%s", type2name(rt), type2name(ct)));

           if (ctype->is_loaded()) {

             const TypeOopPtr* arg_type = TypeOopPtr::make_from_klass(rtype->as_klass());

             const Type*       sig_type = TypeOopPtr::make_from_klass(ctype->as_klass());

             if (arg_type != NULL && !arg_type->higher_equal(sig_type)) {

               Node* retnode = pop();

               Node* cast_obj = _gvn.transform(new (C) CheckCastPPNode(control(), retnode, sig_type));

               push(cast_obj);

             }

           }

         } else {

           assert(rt == ct, err_msg_res("unexpected mismatch: rt=%s, ct=%s", type2name(rt), type2name(ct)));

           // push a zero; it's better than getting an oop/int mismatch

           pop_node(rt);

           Node* retnode = zerocon(ct);

           push_node(ct, retnode);

         }

         // Now that the value is well-behaved, continue with the call-site type.

         rtype = ctype;

       }

     } else {

       // Symbolic resolution enforces the types to be the same.

       // NOTE: We must relax the assert for unloaded types because two

       // different ciType instances of the same unloaded class type

       // can appear to be "loaded" by different loaders (depending on

       // the accessing class).

       assert(!rtype->is_loaded() || !ctype->is_loaded() || rtype == ctype,

              err_msg_res("mismatched return types: rtype=%s, ctype=%s", rtype->name(), ctype->name()));

     }

     // If the return type of the method is not loaded, assert that the

     // value we got is a null.  Otherwise, we need to recompile.

     if (!rtype->is_loaded()) {

 #ifndef PRODUCT

       if (PrintOpto && (Verbose || WizardMode)) {

         method()->print_name(); tty->print_cr(" asserting nullness of result at bci: %d", bci());

         cg->method()->print_name(); tty->cr();

       }

 #endif

       if (C->log() != NULL) {

         C->log()->elem("assert_null reason='return' klass='%d'",

                        C->log()->identify(rtype));

       }

       // If there is going to be a trap, put it at the next bytecode:

       set_bci(iter().next_bci());

       null_assert(peek());

       set_bci(iter().cur_bci()); // put it back

     }

   }

   // Restart record of parsing work after possible inlining of call

 #ifndef PRODUCT

   parse_histogram()->set_initial_state(bc());

 #endif

 }

 //---------------------------catch_call_exceptions-----------------------------

 // Put a Catch and CatchProj nodes behind a just-created call.

 // Send their caught exceptions to the proper handler.

 // This may be used after a call to the rethrow VM stub,

 // when it is needed to process unloaded exception classes.

 void Parse::catch_call_exceptions(ciExceptionHandlerStream& handlers) {

   // Exceptions are delivered through this channel:

   Node* i_o = this->i_o();

   // Add a CatchNode.

   GrowableArray<int>* bcis = new (C->node_arena()) GrowableArray<int>(C->node_arena(), 8, 0, -1);

   GrowableArray<const Type*>* extypes = new (C->node_arena()) GrowableArray<const Type*>(C->node_arena(), 8, 0, NULL);

   GrowableArray<int>* saw_unloaded = new (C->node_arena()) GrowableArray<int>(C->node_arena(), 8, 0, 0);

   for (; !handlers.is_done(); handlers.next()) {

     ciExceptionHandler* h        = handlers.handler();

     int                 h_bci    = h->handler_bci();

     ciInstanceKlass*    h_klass  = h->is_catch_all() ? env()->Throwable_klass() : h->catch_klass();

     // Do not introduce unloaded exception types into the graph:

     if (!h_klass->is_loaded()) {

       if (saw_unloaded->contains(h_bci)) {

         /* We've already seen an unloaded exception with h_bci,

            so don't duplicate. Duplication will cause the CatchNode to be

            unnecessarily large. See 4713716. */

         continue;

       } else {

         saw_unloaded->append(h_bci);

       }

     }

     const Type*         h_extype = TypeOopPtr::make_from_klass(h_klass);

     // (We use make_from_klass because it respects UseUniqueSubclasses.)

     h_extype = h_extype->join(TypeInstPtr::NOTNULL);

     assert(!h_extype->empty(), "sanity");

     // Note:  It's OK if the BCIs repeat themselves.

     bcis->append(h_bci);

     extypes->append(h_extype);

   }

   int len = bcis->length();

   CatchNode *cn = new (C) CatchNode(control(), i_o, len+1);

   Node *catch_ = _gvn.transform(cn);

   // now branch with the exception state to each of the (potential)

   // handlers

   for(int i=0; i < len; i++) {

     // Setup JVM state to enter the handler.

     PreserveJVMState pjvms(this);

     // Locals are just copied from before the call.

     // Get control from the CatchNode.

     int handler_bci = bcis->at(i);

     Node* ctrl = _gvn.transform( new (C) CatchProjNode(catch_, i+1,handler_bci));

     // This handler cannot happen?

     if (ctrl == top())  continue;

     set_control(ctrl);

     // Create exception oop

     const TypeInstPtr* extype = extypes->at(i)->is_instptr();

     Node *ex_oop = _gvn.transform(new (C) CreateExNode(extypes->at(i), ctrl, i_o));

     // Handle unloaded exception classes.

     if (saw_unloaded->contains(handler_bci)) {

       // An unloaded exception type is coming here.  Do an uncommon trap.

 #ifndef PRODUCT

       // We do not expect the same handler bci to take both cold unloaded

       // and hot loaded exceptions.  But, watch for it.

       if ((Verbose || WizardMode) && extype->is_loaded()) {

         tty->print("Warning: Handler @%d takes mixed loaded/unloaded exceptions in ", bci());

         method()->print_name(); tty->cr();

       } else if (PrintOpto && (Verbose || WizardMode)) {

         tty->print("Bailing out on unloaded exception type ");

         extype->klass()->print_name();

         tty->print(" at bci:%d in ", bci());

         method()->print_name(); tty->cr();

       }

 #endif

       // Emit an uncommon trap instead of processing the block.

       set_bci(handler_bci);

       push_ex_oop(ex_oop);

       uncommon_trap(Deoptimization::Reason_unloaded,

                     Deoptimization::Action_reinterpret,

                     extype->klass(), "!loaded exception");

       set_bci(iter().cur_bci()); // put it back

       continue;

     }

     // go to the exception handler

     if (handler_bci < 0) {     // merge with corresponding rethrow node

       throw_to_exit(make_exception_state(ex_oop));

     } else {                      // Else jump to corresponding handle

       push_ex_oop(ex_oop);        // Clear stack and push just the oop.

       merge_exception(handler_bci);

     }

   }

   // The first CatchProj is for the normal return.

   // (Note:  If this is a call to rethrow_Java, this node goes dead.)

   set_control(_gvn.transform( new (C) CatchProjNode(catch_, CatchProjNode::fall_through_index, CatchProjNode::no_handler_bci)));

 }

 //----------------------------catch_inline_exceptions--------------------------

 // Handle all exceptions thrown by an inlined method or individual bytecode.

 // Common case 1: we have no handler, so all exceptions merge right into

 // the rethrow case.

 // Case 2: we have some handlers, with loaded exception klasses that have

 // no subklasses.  We do a Deutsch-Shiffman style type-check on the incoming

 // exception oop and branch to the handler directly.

 // Case 3: We have some handlers with subklasses or are not loaded at

 // compile-time.  We have to call the runtime to resolve the exception.

 // So we insert a RethrowCall and all the logic that goes with it.

 void Parse::catch_inline_exceptions(SafePointNode* ex_map) {

   // Caller is responsible for saving away the map for normal control flow!

   assert(stopped(), "call set_map(NULL) first");

   assert(method()->has_exception_handlers(), "don't come here w/o work to do");

   Node* ex_node = saved_ex_oop(ex_map);

   if (ex_node == top()) {

     // No action needed.

     return;

   }

   const TypeInstPtr* ex_type = _gvn.type(ex_node)->isa_instptr();

   NOT_PRODUCT(if (ex_type==NULL) tty->print_cr("*** Exception not InstPtr"));

   if (ex_type == NULL)

     ex_type = TypeOopPtr::make_from_klass(env()->Throwable_klass())->is_instptr();

   // determine potential exception handlers

   ciExceptionHandlerStream handlers(method(), bci(),

                                     ex_type->klass()->as_instance_klass(),

                                     ex_type->klass_is_exact());

   // Start executing from the given throw state.  (Keep its stack, for now.)

   // Get the exception oop as known at compile time.

   ex_node = use_exception_state(ex_map);

   // Get the exception oop klass from its header

   Node* ex_klass_node = NULL;

   if (has_ex_handler() && !ex_type->klass_is_exact()) {

     Node* p = basic_plus_adr( ex_node, ex_node, oopDesc::klass_offset_in_bytes());

     ex_klass_node = _gvn.transform( LoadKlassNode::make(_gvn, immutable_memory(), p, TypeInstPtr::KLASS, TypeKlassPtr::OBJECT) );

     // Compute the exception klass a little more cleverly.

     // Obvious solution is to simple do a LoadKlass from the 'ex_node'.

     // However, if the ex_node is a PhiNode, I'm going to do a LoadKlass for

     // each arm of the Phi.  If I know something clever about the exceptions

     // I'm loading the class from, I can replace the LoadKlass with the

     // klass constant for the exception oop.

     if( ex_node->is_Phi() ) {

       ex_klass_node = new (C) PhiNode( ex_node->in(0), TypeKlassPtr::OBJECT );

       for( uint i = 1; i < ex_node->req(); i++ ) {

         Node* p = basic_plus_adr( ex_node->in(i), ex_node->in(i), oopDesc::klass_offset_in_bytes() );

         Node* k = _gvn.transform( LoadKlassNode::make(_gvn, immutable_memory(), p, TypeInstPtr::KLASS, TypeKlassPtr::OBJECT) );

         ex_klass_node->init_req( i, k );

       }

       _gvn.set_type(ex_klass_node, TypeKlassPtr::OBJECT);

     }

   }

   // Scan the exception table for applicable handlers.

   // If none, we can call rethrow() and be done!

   // If precise (loaded with no subklasses), insert a D.S. style

   // pointer compare to the correct handler and loop back.

   // If imprecise, switch to the Rethrow VM-call style handling.

   int remaining = handlers.count_remaining();

   // iterate through all entries sequentially

   for (;!handlers.is_done(); handlers.next()) {

     ciExceptionHandler* handler = handlers.handler();

     if (handler->is_rethrow()) {

       // If we fell off the end of the table without finding an imprecise

       // exception klass (and without finding a generic handler) then we

       // know this exception is not handled in this method.  We just rethrow

       // the exception into the caller.

       throw_to_exit(make_exception_state(ex_node));

       return;

     }

     // exception handler bci range covers throw_bci => investigate further

     int handler_bci = handler->handler_bci();

     if (remaining == 1) {

       push_ex_oop(ex_node);        // Push exception oop for handler

 #ifndef PRODUCT

       if (PrintOpto && WizardMode) {

         tty->print_cr("  Catching every inline exception bci:%d -> handler_bci:%d", bci(), handler_bci);

       }

 #endif

       merge_exception(handler_bci); // jump to handler

       return;                   // No more handling to be done here!

     }

     // Get the handler's klass

     ciInstanceKlass* klass = handler->catch_klass();

     if (!klass->is_loaded()) {  // klass is not loaded?

       // fall through into catch_call_exceptions which will emit a

       // handler with an uncommon trap.

       break;

     }

     if (klass->is_interface())  // should not happen, but...

       break;                    // bail out

     // Check the type of the exception against the catch type

     const TypeKlassPtr *tk = TypeKlassPtr::make(klass);

     Node* con = _gvn.makecon(tk);

     Node* not_subtype_ctrl = gen_subtype_check(ex_klass_node, con);

     if (!stopped()) {

       PreserveJVMState pjvms(this);

       const TypeInstPtr* tinst = TypeOopPtr::make_from_klass_unique(klass)->cast_to_ptr_type(TypePtr::NotNull)->is_instptr();

       assert(klass->has_subklass() || tinst->klass_is_exact(), "lost exactness");

       Node* ex_oop = _gvn.transform(new (C) CheckCastPPNode(control(), ex_node, tinst));

       push_ex_oop(ex_oop);      // Push exception oop for handler

 #ifndef PRODUCT

       if (PrintOpto && WizardMode) {

         tty->print("  Catching inline exception bci:%d -> handler_bci:%d -- ", bci(), handler_bci);

         klass->print_name();

         tty->cr();

       }

 #endif

       merge_exception(handler_bci);

     }

     set_control(not_subtype_ctrl);

     // Come here if exception does not match handler.

     // Carry on with more handler checks.

     --remaining;

   }

   assert(!stopped(), "you should return if you finish the chain");

   // Oops, need to call into the VM to resolve the klasses at runtime.

   // Note:  This call must not deoptimize, since it is not a real at this bci!

   kill_dead_locals();

   make_runtime_call(RC_NO_LEAF | RC_MUST_THROW,

                     OptoRuntime::rethrow_Type(),

                     OptoRuntime::rethrow_stub(),

                     NULL, NULL,

                     ex_node);

   // Rethrow is a pure call, no side effects, only a result.

   // The result cannot be allocated, so we use I_O

   // Catch exceptions from the rethrow

   catch_call_exceptions(handlers);

 }

 // (Note:  Moved add_debug_info into GraphKit::add_safepoint_edges.)

 #ifndef PRODUCT

 void Parse::count_compiled_calls(bool at_method_entry, bool is_inline) {

   if( CountCompiledCalls ) {

     if( at_method_entry ) {

       // bump invocation counter if top method (for statistics)

       if (CountCompiledCalls && depth() == 1) {

         const TypePtr* addr_type = TypeMetadataPtr::make(method());

         Node* adr1 = makecon(addr_type);

         Node* adr2 = basic_plus_adr(adr1, adr1, in_bytes(Method::compiled_invocation_counter_offset()));

         increment_counter(adr2);

       }

     } else if (is_inline) {

       switch (bc()) {

       case Bytecodes::_invokevirtual:   increment_counter(SharedRuntime::nof_inlined_calls_addr()); break;

       case Bytecodes::_invokeinterface: increment_counter(SharedRuntime::nof_inlined_interface_calls_addr()); break;

       case Bytecodes::_invokestatic:

       case Bytecodes::_invokedynamic:

       case Bytecodes::_invokespecial:   increment_counter(SharedRuntime::nof_inlined_static_calls_addr()); break;

       default: fatal("unexpected call bytecode");

       }

     } else {

       switch (bc()) {

       case Bytecodes::_invokevirtual:   increment_counter(SharedRuntime::nof_normal_calls_addr()); break;

       case Bytecodes::_invokeinterface: increment_counter(SharedRuntime::nof_interface_calls_addr()); break;

       case Bytecodes::_invokestatic:

       case Bytecodes::_invokedynamic:

       case Bytecodes::_invokespecial:   increment_counter(SharedRuntime::nof_static_calls_addr()); break;

       default: fatal("unexpected call bytecode");

       }

     }

   }

 }

 #endif //PRODUCT

 ciMethod* Compile::optimize_virtual_call(ciMethod* caller, int bci, ciInstanceKlass* klass,

                                          ciMethod* callee, const TypeOopPtr* receiver_type,

                                          bool is_virtual,

                                          bool& call_does_dispatch, int& vtable_index) {

   // Set default values for out-parameters.

   call_does_dispatch = true;

   vtable_index       = Method::invalid_vtable_index;

   // Choose call strategy.

   ciMethod* optimized_virtual_method = optimize_inlining(caller, bci, klass, callee, receiver_type);

   // Have the call been sufficiently improved such that it is no longer a virtual?

   if (optimized_virtual_method != NULL) {

     callee             = optimized_virtual_method;

     call_does_dispatch = false;

   } else if (!UseInlineCaches && is_virtual && callee->is_loaded()) {

     // We can make a vtable call at this site

     vtable_index = callee->resolve_vtable_index(caller->holder(), klass);

   }

   return callee;

 }

 // Identify possible target method and inlining style

 ciMethod* Compile::optimize_inlining(ciMethod* caller, int bci, ciInstanceKlass* klass,

                                      ciMethod* callee, const TypeOopPtr* receiver_type) {

   // only use for virtual or interface calls

   // If it is obviously final, do not bother to call find_monomorphic_target,

   // because the class hierarchy checks are not needed, and may fail due to

   // incompletely loaded classes.  Since we do our own class loading checks

   // in this module, we may confidently bind to any method.

   if (callee->can_be_statically_bound()) {

     return callee;

   }

   // Attempt to improve the receiver

   bool actual_receiver_is_exact = false;

   ciInstanceKlass* actual_receiver = klass;

   if (receiver_type != NULL) {

     // Array methods are all inherited from Object, and are monomorphic.

     if (receiver_type->isa_aryptr() &&

         callee->holder() == env()->Object_klass()) {

       return callee;

     }

     // All other interesting cases are instance klasses.

     if (!receiver_type->isa_instptr()) {

       return NULL;

     }

     ciInstanceKlass *ikl = receiver_type->klass()->as_instance_klass();

     if (ikl->is_loaded() && ikl->is_initialized() && !ikl->is_interface() &&

         (ikl == actual_receiver || ikl->is_subtype_of(actual_receiver))) {

       // ikl is a same or better type than the original actual_receiver,

       // e.g. static receiver from bytecodes.

       actual_receiver = ikl;

       // Is the actual_receiver exact?

       actual_receiver_is_exact = receiver_type->klass_is_exact();

     }

   }

   ciInstanceKlass*   calling_klass = caller->holder();

   ciMethod* cha_monomorphic_target = callee->find_monomorphic_target(calling_klass, klass, actual_receiver);

   if (cha_monomorphic_target != NULL) {

     assert(!cha_monomorphic_target->is_abstract(), "");

     // Look at the method-receiver type.  Does it add "too much information"?

     ciKlass*    mr_klass = cha_monomorphic_target->holder();

     const Type* mr_type  = TypeInstPtr::make(TypePtr::BotPTR, mr_klass);

     if (receiver_type == NULL || !receiver_type->higher_equal(mr_type)) {

       // Calling this method would include an implicit cast to its holder.

       // %%% Not yet implemented.  Would throw minor asserts at present.

       // %%% The most common wins are already gained by +UseUniqueSubclasses.

       // To fix, put the higher_equal check at the call of this routine,

       // and add a CheckCastPP to the receiver.

       if (TraceDependencies) {

         tty->print_cr("found unique CHA method, but could not cast up");

         tty->print("  method  = ");

         cha_monomorphic_target->print();

         tty->cr();

       }

       if (log() != NULL) {

         log()->elem("missed_CHA_opportunity klass='%d' method='%d'",

                        log()->identify(klass),

                        log()->identify(cha_monomorphic_target));

       }

       cha_monomorphic_target = NULL;

     }

   }

   if (cha_monomorphic_target != NULL) {

     // Hardwiring a virtual.

     // If we inlined because CHA revealed only a single target method,

     // then we are dependent on that target method not getting overridden

     // by dynamic class loading.  Be sure to test the "static" receiver

     // dest_method here, as opposed to the actual receiver, which may

     // falsely lead us to believe that the receiver is final or private.

     dependencies()->assert_unique_concrete_method(actual_receiver, cha_monomorphic_target);

     return cha_monomorphic_target;

   }

   // If the type is exact, we can still bind the method w/o a vcall.

   // (This case comes after CHA so we can see how much extra work it does.)

   if (actual_receiver_is_exact) {

     // In case of evolution, there is a dependence on every inlined method, since each

     // such method can be changed when its class is redefined.

     ciMethod* exact_method = callee->resolve_invoke(calling_klass, actual_receiver);

     if (exact_method != NULL) {

 #ifndef PRODUCT

       if (PrintOpto) {

         tty->print("  Calling method via exact type @%d --- ", bci);

         exact_method->print_name();

         tty->cr();

       }

 #endif

       return exact_method;

     }

   }

   return NULL;

 }