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 /*

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  * 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

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  */

 #include "precompiled.hpp"

 #include "classfile/systemDictionary.hpp"

 #include "code/codeCache.hpp"

 #include "code/compiledIC.hpp"

 #include "code/icBuffer.hpp"

 #include "code/nmethod.hpp"

 #include "code/vtableStubs.hpp"

 #include "interpreter/interpreter.hpp"

 #include "interpreter/linkResolver.hpp"

 #include "memory/metadataFactory.hpp"

 #include "memory/oopFactory.hpp"

 #include "oops/method.hpp"

 #include "oops/oop.inline.hpp"

 #include "oops/symbol.hpp"

 #include "runtime/icache.hpp"

 #include "runtime/sharedRuntime.hpp"

 #include "runtime/stubRoutines.hpp"

 #include "utilities/events.hpp"

 // Every time a compiled IC is changed or its type is being accessed,

 // either the CompiledIC_lock must be set or we must be at a safe point.

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

 // Low-level access to an inline cache. Private, since they might not be

 // MT-safe to use.

 void* CompiledIC::cached_value() const {

   assert (CompiledIC_lock->is_locked() || SafepointSynchronize::is_at_safepoint(), "");

   assert (!is_optimized(), "an optimized virtual call does not have a cached metadata");

   if (!is_in_transition_state()) {

     void* data = (void*)_value->data();

     // If we let the metadata value here be initialized to zero...

     assert(data != NULL || Universe::non_oop_word() == NULL,

            "no raw nulls in CompiledIC metadatas, because of patching races");

     return (data == (void*)Universe::non_oop_word()) ? NULL : data;

   } else {

     return InlineCacheBuffer::cached_value_for((CompiledIC *)this);

   }

 }

 void CompiledIC::internal_set_ic_destination(address entry_point, bool is_icstub, void* cache, bool is_icholder) {

   assert(entry_point != NULL, "must set legal entry point");

   assert(CompiledIC_lock->is_locked() || SafepointSynchronize::is_at_safepoint(), "");

   assert (!is_optimized() || cache == NULL, "an optimized virtual call does not have a cached metadata");

   assert (cache == NULL || cache != (Metadata*)badOopVal, "invalid metadata");

   assert(!is_icholder || is_icholder_entry(entry_point), "must be");

   // Don't use ic_destination for this test since that forwards

   // through ICBuffer instead of returning the actual current state of

   // the CompiledIC.

   if (is_icholder_entry(_ic_call->destination())) {

     // When patching for the ICStub case the cached value isn't

     // overwritten until the ICStub copied into the CompiledIC during

     // the next safepoint.  Make sure that the CompiledICHolder* is

     // marked for release at this point since it won't be identifiable

     // once the entry point is overwritten.

     InlineCacheBuffer::queue_for_release((CompiledICHolder*)_value->data());

   }

   if (TraceCompiledIC) {

     tty->print("  ");

     print_compiled_ic();

     tty->print(" changing destination to " INTPTR_FORMAT, entry_point);

     if (!is_optimized()) {

       tty->print(" changing cached %s to " INTPTR_FORMAT, is_icholder ? "icholder" : "metadata", (address)cache);

     }

     if (is_icstub) {

       tty->print(" (icstub)");

     }

     tty->cr();

   }

   {

   MutexLockerEx pl(Patching_lock, Mutex::_no_safepoint_check_flag);

 #ifdef ASSERT

   CodeBlob* cb = CodeCache::find_blob_unsafe(_ic_call);

   assert(cb != NULL && cb->is_nmethod(), "must be nmethod");

 #endif

   _ic_call->set_destination_mt_safe(entry_point);

 }

   if (is_optimized() || is_icstub) {

     // Optimized call sites don't have a cache value and ICStub call

     // sites only change the entry point.  Changing the value in that

     // case could lead to MT safety issues.

     assert(cache == NULL, "must be null");

     return;

   }

   if (cache == NULL)  cache = (void*)Universe::non_oop_word();

   _value->set_data((intptr_t)cache);

 }

 void CompiledIC::set_ic_destination(ICStub* stub) {

   internal_set_ic_destination(stub->code_begin(), true, NULL, false);

 }

 address CompiledIC::ic_destination() const {

  assert (CompiledIC_lock->is_locked() || SafepointSynchronize::is_at_safepoint(), "");

  if (!is_in_transition_state()) {

    return _ic_call->destination();

  } else {

    return InlineCacheBuffer::ic_destination_for((CompiledIC *)this);

  }

 }

 bool CompiledIC::is_in_transition_state() const {

   assert (CompiledIC_lock->is_locked() || SafepointSynchronize::is_at_safepoint(), "");

   return InlineCacheBuffer::contains(_ic_call->destination());

 }

 bool CompiledIC::is_icholder_call() const {

   assert (CompiledIC_lock->is_locked() || SafepointSynchronize::is_at_safepoint(), "");

   return !_is_optimized && is_icholder_entry(ic_destination());

 }

 // Returns native address of 'call' instruction in inline-cache. Used by

 // the InlineCacheBuffer when it needs to find the stub.

 address CompiledIC::stub_address() const {

   assert(is_in_transition_state(), "should only be called when we are in a transition state");

   return _ic_call->destination();

 }

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

 // High-level access to an inline cache. Guaranteed to be MT-safe.

 void CompiledIC::set_to_megamorphic(CallInfo* call_info, Bytecodes::Code bytecode, TRAPS) {

   assert(CompiledIC_lock->is_locked() || SafepointSynchronize::is_at_safepoint(), "");

   assert(!is_optimized(), "cannot set an optimized virtual call to megamorphic");

   assert(is_call_to_compiled() || is_call_to_interpreted(), "going directly to megamorphic?");

   address entry;

   if (call_info->call_kind() == CallInfo::itable_call) {

     assert(bytecode == Bytecodes::_invokeinterface, "");

     int itable_index = call_info->itable_index();

     entry = VtableStubs::find_itable_stub(itable_index);

 #ifdef ASSERT

     assert(entry != NULL, "entry not computed");

     int index = call_info->resolved_method()->itable_index();

     assert(index == itable_index, "CallInfo pre-computes this");

 #endif //ASSERT

     InstanceKlass* k = call_info->resolved_method()->method_holder();

     assert(k->verify_itable_index(itable_index), "sanity check");

     InlineCacheBuffer::create_transition_stub(this, k, entry);

   } else {

     assert(call_info->call_kind() == CallInfo::vtable_call, "either itable or vtable");

     // Can be different than selected_method->vtable_index(), due to package-private etc.

     int vtable_index = call_info->vtable_index();

     assert(call_info->resolved_klass()->verify_vtable_index(vtable_index), "sanity check");

     entry = VtableStubs::find_vtable_stub(vtable_index);

     InlineCacheBuffer::create_transition_stub(this, NULL, entry);

   }

   if (TraceICs) {

     ResourceMark rm;

     tty->print_cr ("IC@" INTPTR_FORMAT ": to megamorphic %s entry: " INTPTR_FORMAT,

                    instruction_address(), call_info->selected_method()->print_value_string(), entry);

   }

   // We can't check this anymore. With lazy deopt we could have already

   // cleaned this IC entry before we even return. This is possible if

   // we ran out of space in the inline cache buffer trying to do the

   // set_next and we safepointed to free up space. This is a benign

   // race because the IC entry was complete when we safepointed so

   // cleaning it immediately is harmless.

   // assert(is_megamorphic(), "sanity check");

 }

 // true if destination is megamorphic stub

 bool CompiledIC::is_megamorphic() const {

   assert(CompiledIC_lock->is_locked() || SafepointSynchronize::is_at_safepoint(), "");

   assert(!is_optimized(), "an optimized call cannot be megamorphic");

   // Cannot rely on cached_value. It is either an interface or a method.

   return VtableStubs::is_entry_point(ic_destination());

 }

 bool CompiledIC::is_call_to_compiled() const {

   assert (CompiledIC_lock->is_locked() || SafepointSynchronize::is_at_safepoint(), "");

   // Use unsafe, since an inline cache might point to a zombie method. However, the zombie

   // method is guaranteed to still exist, since we only remove methods after all inline caches

   // has been cleaned up

   CodeBlob* cb = CodeCache::find_blob_unsafe(ic_destination());

   bool is_monomorphic = (cb != NULL && cb->is_nmethod());

   // Check that the cached_value is a klass for non-optimized monomorphic calls

   // This assertion is invalid for compiler1: a call that does not look optimized (no static stub) can be used

   // for calling directly to vep without using the inline cache (i.e., cached_value == NULL)

 #ifdef ASSERT

   CodeBlob* caller = CodeCache::find_blob_unsafe(instruction_address());

   bool is_c1_method = caller->is_compiled_by_c1();

   assert( is_c1_method ||

          !is_monomorphic ||

          is_optimized() ||

          (cached_metadata() != NULL && cached_metadata()->is_klass()), "sanity check");

 #endif // ASSERT

   return is_monomorphic;

 }

 bool CompiledIC::is_call_to_interpreted() const {

   assert (CompiledIC_lock->is_locked() || SafepointSynchronize::is_at_safepoint(), "");

   // Call to interpreter if destination is either calling to a stub (if it

   // is optimized), or calling to an I2C blob

   bool is_call_to_interpreted = false;

   if (!is_optimized()) {

     // must use unsafe because the destination can be a zombie (and we're cleaning)

     // and the print_compiled_ic code wants to know if site (in the non-zombie)

     // is to the interpreter.

     CodeBlob* cb = CodeCache::find_blob_unsafe(ic_destination());

     is_call_to_interpreted = (cb != NULL && cb->is_adapter_blob());

     assert(!is_call_to_interpreted || (is_icholder_call() && cached_icholder() != NULL), "sanity check");

   } else {

     // Check if we are calling into our own codeblob (i.e., to a stub)

     CodeBlob* cb = CodeCache::find_blob(_ic_call->instruction_address());

     address dest = ic_destination();

 #ifdef ASSERT

     {

       CodeBlob* db = CodeCache::find_blob_unsafe(dest);

       assert(!db->is_adapter_blob(), "must use stub!");

     }

 #endif /* ASSERT */

     is_call_to_interpreted = cb->contains(dest);

   }

   return is_call_to_interpreted;

 }

 void CompiledIC::set_to_clean() {

   assert(SafepointSynchronize::is_at_safepoint() || CompiledIC_lock->is_locked() , "MT-unsafe call");

   if (TraceInlineCacheClearing || TraceICs) {

     tty->print_cr("IC@" INTPTR_FORMAT ": set to clean", instruction_address());

     print();

   }

   address entry;

   if (is_optimized()) {

     entry = SharedRuntime::get_resolve_opt_virtual_call_stub();

   } else {

     entry = SharedRuntime::get_resolve_virtual_call_stub();

   }

   // A zombie transition will always be safe, since the metadata has already been set to NULL, so

   // we only need to patch the destination

   bool safe_transition = is_optimized() || SafepointSynchronize::is_at_safepoint();

   if (safe_transition) {

     // Kill any leftover stub we might have too

     if (is_in_transition_state()) {

       ICStub* old_stub = ICStub_from_destination_address(stub_address());

       old_stub->clear();

     }

     if (is_optimized()) {

     set_ic_destination(entry);

   } else {

       set_ic_destination_and_value(entry, (void*)NULL);

     }

   } else {

     // Unsafe transition - create stub.

     InlineCacheBuffer::create_transition_stub(this, NULL, entry);

   }

   // We can't check this anymore. With lazy deopt we could have already

   // cleaned this IC entry before we even return. This is possible if

   // we ran out of space in the inline cache buffer trying to do the

   // set_next and we safepointed to free up space. This is a benign

   // race because the IC entry was complete when we safepointed so

   // cleaning it immediately is harmless.

   // assert(is_clean(), "sanity check");

 }

 bool CompiledIC::is_clean() const {

   assert (CompiledIC_lock->is_locked() || SafepointSynchronize::is_at_safepoint(), "");

   bool is_clean = false;

   address dest = ic_destination();

   is_clean = dest == SharedRuntime::get_resolve_opt_virtual_call_stub() ||

              dest == SharedRuntime::get_resolve_virtual_call_stub();

   assert(!is_clean || is_optimized() || cached_value() == NULL, "sanity check");

   return is_clean;

 }

 void CompiledIC::set_to_monomorphic(CompiledICInfo& info) {

   assert (CompiledIC_lock->is_locked() || SafepointSynchronize::is_at_safepoint(), "");

   // Updating a cache to the wrong entry can cause bugs that are very hard

   // to track down - if cache entry gets invalid - we just clean it. In

   // this way it is always the same code path that is responsible for

   // updating and resolving an inline cache

   //

   // The above is no longer true. SharedRuntime::fixup_callers_callsite will change optimized

   // callsites. In addition ic_miss code will update a site to monomorphic if it determines

   // that an monomorphic call to the interpreter can now be monomorphic to compiled code.

   //

   // In both of these cases the only thing being modifed is the jump/call target and these

   // transitions are mt_safe

   Thread *thread = Thread::current();

   if (info.to_interpreter()) {

     // Call to interpreter

     if (info.is_optimized() && is_optimized()) {

        assert(is_clean(), "unsafe IC path");

        MutexLockerEx pl(Patching_lock, Mutex::_no_safepoint_check_flag);

       // the call analysis (callee structure) specifies that the call is optimized

       // (either because of CHA or the static target is final)

       // At code generation time, this call has been emitted as static call

       // Call via stub

       assert(info.cached_metadata() != NULL && info.cached_metadata()->is_method(), "sanity check");

       CompiledStaticCall* csc = compiledStaticCall_at(instruction_address());

       methodHandle method (thread, (Method*)info.cached_metadata());

       csc->set_to_interpreted(method, info.entry());

       if (TraceICs) {

          ResourceMark rm(thread);

          tty->print_cr ("IC@" INTPTR_FORMAT ": monomorphic to interpreter: %s",

            instruction_address(),

            method->print_value_string());

       }

     } else {

       // Call via method-klass-holder

       InlineCacheBuffer::create_transition_stub(this, info.claim_cached_icholder(), info.entry());

       if (TraceICs) {

          ResourceMark rm(thread);

          tty->print_cr ("IC@" INTPTR_FORMAT ": monomorphic to interpreter via icholder ", instruction_address());

       }

     }

   } else {

     // Call to compiled code

     bool static_bound = info.is_optimized() || (info.cached_metadata() == NULL);

 #ifdef ASSERT

     CodeBlob* cb = CodeCache::find_blob_unsafe(info.entry());

     assert (cb->is_nmethod(), "must be compiled!");

 #endif /* ASSERT */

     // This is MT safe if we come from a clean-cache and go through a

     // non-verified entry point

     bool safe = SafepointSynchronize::is_at_safepoint() ||

                 (!is_in_transition_state() && (info.is_optimized() || static_bound || is_clean()));

     if (!safe) {

       InlineCacheBuffer::create_transition_stub(this, info.cached_metadata(), info.entry());

     } else {

       if (is_optimized()) {

       set_ic_destination(info.entry());

       } else {

         set_ic_destination_and_value(info.entry(), info.cached_metadata());

       }

     }

     if (TraceICs) {

       ResourceMark rm(thread);

       assert(info.cached_metadata() == NULL || info.cached_metadata()->is_klass(), "must be");

       tty->print_cr ("IC@" INTPTR_FORMAT ": monomorphic to compiled (rcvr klass) %s: %s",

         instruction_address(),

         ((Klass*)info.cached_metadata())->print_value_string(),

         (safe) ? "" : "via stub");

     }

   }

   // We can't check this anymore. With lazy deopt we could have already

   // cleaned this IC entry before we even return. This is possible if

   // we ran out of space in the inline cache buffer trying to do the

   // set_next and we safepointed to free up space. This is a benign

   // race because the IC entry was complete when we safepointed so

   // cleaning it immediately is harmless.

   // assert(is_call_to_compiled() || is_call_to_interpreted(), "sanity check");

 }

 // is_optimized: Compiler has generated an optimized call (i.e., no inline

 // cache) static_bound: The call can be static bound (i.e, no need to use

 // inline cache)

 void CompiledIC::compute_monomorphic_entry(methodHandle method,

                                            KlassHandle receiver_klass,

                                            bool is_optimized,

                                            bool static_bound,

                                            CompiledICInfo& info,

                                            TRAPS) {

   nmethod* method_code = method->code();

   address entry = NULL;

   if (method_code != NULL) {

     // Call to compiled code

     if (static_bound || is_optimized) {

       entry      = method_code->verified_entry_point();

     } else {

       entry      = method_code->entry_point();

     }

   }

   if (entry != NULL) {

     // Call to compiled code

     info.set_compiled_entry(entry, (static_bound || is_optimized) ? NULL : receiver_klass(), is_optimized);

   } else {

     // Note: the following problem exists with Compiler1:

     //   - at compile time we may or may not know if the destination is final

     //   - if we know that the destination is final, we will emit an optimized

     //     virtual call (no inline cache), and need a Method* to make a call

     //     to the interpreter

     //   - if we do not know if the destination is final, we emit a standard

     //     virtual call, and use CompiledICHolder to call interpreted code

     //     (no static call stub has been generated)

     //     However in that case we will now notice it is static_bound

     //     and convert the call into what looks to be an optimized

     //     virtual call. This causes problems in verifying the IC because

     //     it look vanilla but is optimized. Code in is_call_to_interpreted

     //     is aware of this and weakens its asserts.

     // static_bound should imply is_optimized -- otherwise we have a

     // performance bug (statically-bindable method is called via

     // dynamically-dispatched call note: the reverse implication isn't

     // necessarily true -- the call may have been optimized based on compiler

     // analysis (static_bound is only based on "final" etc.)

 #ifdef COMPILER2

 #ifdef TIERED

 #if defined(ASSERT)

     // can't check the assert because we don't have the CompiledIC with which to

     // find the address if the call instruction.

     //

     // CodeBlob* cb = find_blob_unsafe(instruction_address());

     // assert(cb->is_compiled_by_c1() || !static_bound || is_optimized, "static_bound should imply is_optimized");

 #endif // ASSERT

 #else

     assert(!static_bound || is_optimized, "static_bound should imply is_optimized");

 #endif // TIERED

 #endif // COMPILER2

     if (is_optimized) {

       // Use stub entry

       info.set_interpreter_entry(method()->get_c2i_entry(), method());

     } else {

       // Use icholder entry

       CompiledICHolder* holder = new CompiledICHolder(method(), receiver_klass());

       info.set_icholder_entry(method()->get_c2i_unverified_entry(), holder);

     }

   }

   assert(info.is_optimized() == is_optimized, "must agree");

 }

 bool CompiledIC::is_icholder_entry(address entry) {

   CodeBlob* cb = CodeCache::find_blob_unsafe(entry);

   return (cb != NULL && cb->is_adapter_blob());

 }

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

 void CompiledStaticCall::set_to_clean() {

   assert (CompiledIC_lock->is_locked() || SafepointSynchronize::is_at_safepoint(), "mt unsafe call");

   // Reset call site

   MutexLockerEx pl(Patching_lock, Mutex::_no_safepoint_check_flag);

 #ifdef ASSERT

   CodeBlob* cb = CodeCache::find_blob_unsafe(this);

   assert(cb != NULL && cb->is_nmethod(), "must be nmethod");

 #endif

   set_destination_mt_safe(SharedRuntime::get_resolve_static_call_stub());

   // Do not reset stub here:  It is too expensive to call find_stub.

   // Instead, rely on caller (nmethod::clear_inline_caches) to clear

   // both the call and its stub.

 }

 bool CompiledStaticCall::is_clean() const {

   return destination() == SharedRuntime::get_resolve_static_call_stub();

 }

 bool CompiledStaticCall::is_call_to_compiled() const {

   return CodeCache::contains(destination());

 }

 bool CompiledStaticCall::is_call_to_interpreted() const {

   // It is a call to interpreted, if it calls to a stub. Hence, the destination

   // must be in the stub part of the nmethod that contains the call

   nmethod* nm = CodeCache::find_nmethod(instruction_address());

   return nm->stub_contains(destination());

 }

 void CompiledStaticCall::set(const StaticCallInfo& info) {

   assert (CompiledIC_lock->is_locked() || SafepointSynchronize::is_at_safepoint(), "mt unsafe call");

   MutexLockerEx pl(Patching_lock, Mutex::_no_safepoint_check_flag);

   // Updating a cache to the wrong entry can cause bugs that are very hard

   // to track down - if cache entry gets invalid - we just clean it. In

   // this way it is always the same code path that is responsible for

   // updating and resolving an inline cache

   assert(is_clean(), "do not update a call entry - use clean");

   if (info._to_interpreter) {

     // Call to interpreted code

     set_to_interpreted(info.callee(), info.entry());

   } else {

     if (TraceICs) {

       ResourceMark rm;

       tty->print_cr("CompiledStaticCall@" INTPTR_FORMAT ": set_to_compiled " INTPTR_FORMAT,

                     instruction_address(),

                     info.entry());

     }

     // Call to compiled code

     assert (CodeCache::contains(info.entry()), "wrong entry point");

     set_destination_mt_safe(info.entry());

   }

 }

 // Compute settings for a CompiledStaticCall. Since we might have to set

 // the stub when calling to the interpreter, we need to return arguments.

 void CompiledStaticCall::compute_entry(methodHandle m, StaticCallInfo& info) {

   nmethod* m_code = m->code();

   info._callee = m;

   if (m_code != NULL) {

     info._to_interpreter = false;

     info._entry  = m_code->verified_entry_point();

   } else {

     // Callee is interpreted code.  In any case entering the interpreter

     // puts a converter-frame on the stack to save arguments.

     info._to_interpreter = true;

     info._entry      = m()->get_c2i_entry();

   }

 }

 address CompiledStaticCall::find_stub() {

   // Find reloc. information containing this call-site

   RelocIterator iter((nmethod*)NULL, instruction_address());

   while (iter.next()) {

     if (iter.addr() == instruction_address()) {

       switch(iter.type()) {

         case relocInfo::static_call_type:

           return iter.static_call_reloc()->static_stub();

         // We check here for opt_virtual_call_type, since we reuse the code

         // from the CompiledIC implementation

         case relocInfo::opt_virtual_call_type:

           return iter.opt_virtual_call_reloc()->static_stub();

         case relocInfo::poll_type:

         case relocInfo::poll_return_type: // A safepoint can't overlap a call.

         default:

           ShouldNotReachHere();

       }

     }

   }

   return NULL;

 }

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

 // Non-product mode code

 #ifndef PRODUCT

 void CompiledIC::verify() {

   // make sure code pattern is actually a call imm32 instruction

   _ic_call->verify();

   if (os::is_MP()) {

     _ic_call->verify_alignment();

   }

   assert(is_clean() || is_call_to_compiled() || is_call_to_interpreted()

           || is_optimized() || is_megamorphic(), "sanity check");

 }

 void CompiledIC::print() {

   print_compiled_ic();

   tty->cr();

 }

 void CompiledIC::print_compiled_ic() {

   tty->print("Inline cache at " INTPTR_FORMAT ", calling %s " INTPTR_FORMAT " cached_value " INTPTR_FORMAT,

              instruction_address(), is_call_to_interpreted() ? "interpreted " : "", ic_destination(), is_optimized() ? NULL : cached_value());

 }

 void CompiledStaticCall::print() {

   tty->print("static call at " INTPTR_FORMAT " -> ", instruction_address());

   if (is_clean()) {

     tty->print("clean");

   } else if (is_call_to_compiled()) {

     tty->print("compiled");

   } else if (is_call_to_interpreted()) {

     tty->print("interpreted");

   }

   tty->cr();

 }

 #endif // !PRODUCT