/*

 * Copyright (c) 1997, 2010, 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.

 *

 */

// 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::set_cached_oop(oop cache) {

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

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

  assert (cache == NULL || cache != badOop, "invalid oop");

  if (TraceCompiledIC) {

    tty->print("  ");

    print_compiled_ic();

    tty->print_cr(" changing oop to " INTPTR_FORMAT, (address)cache);

  }

  if (cache == NULL)  cache = (oop)Universe::non_oop_word();

  *_oop_addr = cache;

  // fix up the relocations

  RelocIterator iter = _oops;

  while (iter.next()) {

    if (iter.type() == relocInfo::oop_type) {

      oop_Relocation* r = iter.oop_reloc();

      if (r->oop_addr() == _oop_addr)

        r->fix_oop_relocation();

    }

  }

  return;

}

oop CompiledIC::cached_oop() const {

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

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

  if (!is_in_transition_state()) {

    oop data = *_oop_addr;

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

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

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

    return (data == (oop)Universe::non_oop_word()) ? (oop)NULL : data;

  } else {

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

  }

}

void CompiledIC::set_ic_destination(address entry_point) {

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

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

  if (TraceCompiledIC) {

    tty->print("  ");

    print_compiled_ic();

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

  }

  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);

}

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());

}

// 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) {

  methodHandle method = call_info->selected_method();

  bool is_invoke_interface = (bytecode == Bytecodes::_invokeinterface && !call_info->has_vtable_index());

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

  assert(method->is_oop(), "cannot be NULL and must be oop");

  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 (is_invoke_interface) {

    int index = klassItable::compute_itable_index(call_info->resolved_method()());

    entry = VtableStubs::create_stub(false, index, method());

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

    klassOop k = call_info->resolved_method()->method_holder();

    assert(Klass::cast(k)->is_interface(), "sanity check");

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

  } else {

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

    int vtable_index = call_info->vtable_index();

    entry = VtableStubs::create_stub(true, vtable_index, method());

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

  }

  if (TraceICs) {

    ResourceMark rm;

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

                   instruction_address(), method->print_value_string(), entry);

  }

  Events::log("compiledIC " INTPTR_FORMAT " --> megamorphic " INTPTR_FORMAT, this, (address)method());

  // 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_oop. 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_oop 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_oop == NULL)

#ifdef ASSERT

#ifdef TIERED

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

  bool is_c1_method = caller->is_compiled_by_c1();

#else

#ifdef COMPILER1

  bool is_c1_method = true;

#else

  bool is_c1_method = false;

#endif // COMPILER1

#endif // TIERED

  assert( is_c1_method ||

         !is_monomorphic ||

         is_optimized() ||

         (cached_oop() != NULL && cached_oop()->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 ||  (cached_oop() != NULL && cached_oop()->is_compiledICHolder()), "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 oop 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) {

    if (!is_optimized()) set_cached_oop(NULL);

    // 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();

    }

    set_ic_destination(entry);

  } 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_oop() == NULL, "sanity check");

  return is_clean;

}

void CompiledIC::set_to_monomorphic(const 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_oop().not_null() && info.cached_oop()->is_method(), "sanity check");

      CompiledStaticCall* csc = compiledStaticCall_at(instruction_address());

      methodHandle method (thread, (methodOop)info.cached_oop()());

      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

      assert(info.cached_oop().not_null(), "must be set");

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

      if (TraceICs) {

         ResourceMark rm(thread);

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

      }

    }

  } else {

    // Call to compiled code

    bool static_bound = info.is_optimized() || (info.cached_oop().is_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_oop()(), info.entry());

    } else {

      set_ic_destination(info.entry());

      if (!is_optimized()) set_cached_oop(info.cached_oop()());

    }

    if (TraceICs) {

      ResourceMark rm(thread);

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

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

        instruction_address(),

        ((klassOop)info.cached_oop()())->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) {

  info._is_optimized = is_optimized;

  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._entry      = entry;

    if (static_bound || is_optimized) {

      info._cached_oop = Handle(THREAD, (oop)NULL);

    } else {

      info._cached_oop = receiver_klass;

    }

    info._to_interpreter = false;

  } 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 methodOop 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.

    info._to_interpreter = true;

    // 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._entry      = method()->get_c2i_entry();

      info._cached_oop = method;

    } else {

      // Use mkh entry

      oop holder = oopFactory::new_compiledICHolder(method, receiver_klass, CHECK);

      info._cached_oop = Handle(THREAD, holder);

      info._entry      = method()->get_c2i_unverified_entry();

    }

  }

}

inline static RelocIterator parse_ic(nmethod* nm, address ic_call, oop* &_oop_addr, bool *is_optimized) {

   address  first_oop = NULL;

   // Mergers please note: Sun SC5.x CC insists on an lvalue for a reference parameter.

   nmethod* tmp_nm = nm;

   return virtual_call_Relocation::parse_ic(tmp_nm, ic_call, first_oop, _oop_addr, is_optimized);

}

CompiledIC::CompiledIC(NativeCall* ic_call)

  : _ic_call(ic_call),

    _oops(parse_ic(NULL, ic_call->instruction_address(), _oop_addr, &_is_optimized))

{

}

CompiledIC::CompiledIC(Relocation* ic_reloc)

  : _ic_call(nativeCall_at(ic_reloc->addr())),

    _oops(parse_ic(ic_reloc->code(), ic_reloc->addr(), _oop_addr, &_is_optimized))

{

  assert(ic_reloc->type() == relocInfo::virtual_call_type ||

         ic_reloc->type() == relocInfo::opt_virtual_call_type, "wrong reloc. info");

}

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

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_to_interpreted(methodHandle callee, address entry) {

  address stub=find_stub();

  assert(stub!=NULL, "stub not found");

  if (TraceICs) {

    ResourceMark rm;

    tty->print_cr("CompiledStaticCall@" INTPTR_FORMAT ": set_to_interpreted %s",

                  instruction_address(),

                  callee->name_and_sig_as_C_string());

  }