/*

 * Copyright (c) 1999, 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.

 *

 */

// ciMethod

//

// This class represents a methodOop in the HotSpot virtual

// machine.

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

// ciMethod::ciMethod

//

// Loaded method.

ciMethod::ciMethod(methodHandle h_m) : ciObject(h_m) {

  assert(h_m() != NULL, "no null method");

  // These fields are always filled in in loaded methods.

  _flags = ciFlags(h_m()->access_flags());

  // Easy to compute, so fill them in now.

  _max_stack          = h_m()->max_stack();

  _max_locals         = h_m()->max_locals();

  _code_size          = h_m()->code_size();

  _intrinsic_id       = h_m()->intrinsic_id();

  _handler_count      = h_m()->exception_table()->length() / 4;

  _uses_monitors      = h_m()->access_flags().has_monitor_bytecodes();

  _balanced_monitors  = !_uses_monitors || h_m()->access_flags().is_monitor_matching();

  _is_c1_compilable   = !h_m()->is_not_c1_compilable();

  _is_c2_compilable   = !h_m()->is_not_c2_compilable();

  // Lazy fields, filled in on demand.  Require allocation.

  _code               = NULL;

  _exception_handlers = NULL;

  _liveness           = NULL;

  _method_blocks = NULL;

#if defined(COMPILER2) || defined(SHARK)

  _flow               = NULL;

  _bcea               = NULL;

#endif // COMPILER2 || SHARK

  ciEnv *env = CURRENT_ENV;

  if (env->jvmti_can_hotswap_or_post_breakpoint() && can_be_compiled()) {

    // 6328518 check hotswap conditions under the right lock.

    MutexLocker locker(Compile_lock);

    if (Dependencies::check_evol_method(h_m()) != NULL) {

      _is_c1_compilable = false;

      _is_c2_compilable = false;

    }

  } else {

    CHECK_UNHANDLED_OOPS_ONLY(Thread::current()->clear_unhandled_oops());

  }

  if (instanceKlass::cast(h_m()->method_holder())->is_linked()) {

    _can_be_statically_bound = h_m()->can_be_statically_bound();

  } else {

    // Have to use a conservative value in this case.

    _can_be_statically_bound = false;

  }

  // Adjust the definition of this condition to be more useful:

  // %%% take these conditions into account in vtable generation

  if (!_can_be_statically_bound && h_m()->is_private())

    _can_be_statically_bound = true;

  if (_can_be_statically_bound && h_m()->is_abstract())

    _can_be_statically_bound = false;

  // generating _signature may allow GC and therefore move m.

  // These fields are always filled in.

  _name = env->get_object(h_m()->name())->as_symbol();

  _holder = env->get_object(h_m()->method_holder())->as_instance_klass();

  ciSymbol* sig_symbol = env->get_object(h_m()->signature())->as_symbol();

  _signature = new (env->arena()) ciSignature(_holder, sig_symbol);

  _method_data = NULL;

  // Take a snapshot of these values, so they will be commensurate with the MDO.

  if (ProfileInterpreter || TieredCompilation) {

    int invcnt = h_m()->interpreter_invocation_count();

    // if the value overflowed report it as max int

    _interpreter_invocation_count = invcnt < 0 ? max_jint : invcnt ;

    _interpreter_throwout_count   = h_m()->interpreter_throwout_count();

  } else {

    _interpreter_invocation_count = 0;

    _interpreter_throwout_count = 0;

  }

  if (_interpreter_invocation_count == 0)

    _interpreter_invocation_count = 1;

}

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

// ciMethod::ciMethod

//

// Unloaded method.

ciMethod::ciMethod(ciInstanceKlass* holder,

                   ciSymbol* name,

                   ciSymbol* signature) : ciObject(ciMethodKlass::make()) {

  // These fields are always filled in.

  _name = name;

  _holder = holder;

  _signature = new (CURRENT_ENV->arena()) ciSignature(_holder, signature);

  _intrinsic_id = vmIntrinsics::_none;

  _liveness = NULL;

  _can_be_statically_bound = false;

  _method_blocks = NULL;

  _method_data = NULL;

#if defined(COMPILER2) || defined(SHARK)

  _flow = NULL;

  _bcea = NULL;

#endif // COMPILER2 || SHARK

}

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

// ciMethod::load_code

//

// Load the bytecodes and exception handler table for this method.

void ciMethod::load_code() {

  VM_ENTRY_MARK;

  assert(is_loaded(), "only loaded methods have code");

  methodOop me = get_methodOop();

  Arena* arena = CURRENT_THREAD_ENV->arena();

  // Load the bytecodes.

  _code = (address)arena->Amalloc(code_size());

  memcpy(_code, me->code_base(), code_size());

  // Revert any breakpoint bytecodes in ci's copy

  if (me->number_of_breakpoints() > 0) {

    BreakpointInfo* bp = instanceKlass::cast(me->method_holder())->breakpoints();

    for (; bp != NULL; bp = bp->next()) {

      if (bp->match(me)) {

        code_at_put(bp->bci(), bp->orig_bytecode());

      }

    }

  }

  // And load the exception table.

  typeArrayOop exc_table = me->exception_table();

  // Allocate one extra spot in our list of exceptions.  This

  // last entry will be used to represent the possibility that

  // an exception escapes the method.  See ciExceptionHandlerStream

  // for details.

  _exception_handlers =

    (ciExceptionHandler**)arena->Amalloc(sizeof(ciExceptionHandler*)

                                         * (_handler_count + 1));

  if (_handler_count > 0) {

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

      int base = i*4;

      _exception_handlers[i] = new (arena) ciExceptionHandler(

                                holder(),

            /* start    */      exc_table->int_at(base),

            /* limit    */      exc_table->int_at(base+1),

            /* goto pc  */      exc_table->int_at(base+2),

            /* cp index */      exc_table->int_at(base+3));

    }

  }

  // Put an entry at the end of our list to represent the possibility

  // of exceptional exit.

  _exception_handlers[_handler_count] =

    new (arena) ciExceptionHandler(holder(), 0, code_size(), -1, 0);

  if (CIPrintMethodCodes) {

    print_codes();

  }

}

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

// ciMethod::has_linenumber_table

//

// length unknown until decompression

bool    ciMethod::has_linenumber_table() const {

  check_is_loaded();

  VM_ENTRY_MARK;

  return get_methodOop()->has_linenumber_table();

}

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

// ciMethod::compressed_linenumber_table

u_char* ciMethod::compressed_linenumber_table() const {

  check_is_loaded();

  VM_ENTRY_MARK;

  return get_methodOop()->compressed_linenumber_table();

}

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

// ciMethod::line_number_from_bci

int ciMethod::line_number_from_bci(int bci) const {

  check_is_loaded();

  VM_ENTRY_MARK;

  return get_methodOop()->line_number_from_bci(bci);

}

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

// ciMethod::vtable_index

//

// Get the position of this method's entry in the vtable, if any.

int ciMethod::vtable_index() {

  check_is_loaded();

  assert(holder()->is_linked(), "must be linked");

  VM_ENTRY_MARK;

  return get_methodOop()->vtable_index();

}

#ifdef SHARK

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

// ciMethod::itable_index

//

// Get the position of this method's entry in the itable, if any.

int ciMethod::itable_index() {

  check_is_loaded();

  assert(holder()->is_linked(), "must be linked");

  VM_ENTRY_MARK;

  return klassItable::compute_itable_index(get_methodOop());

}

#endif // SHARK

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

// ciMethod::native_entry

//

// Get the address of this method's native code, if any.

address ciMethod::native_entry() {

  check_is_loaded();

  assert(flags().is_native(), "must be native method");

  VM_ENTRY_MARK;

  methodOop method = get_methodOop();

  address entry = method->native_function();

  assert(entry != NULL, "must be valid entry point");

  return entry;

}

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

// ciMethod::interpreter_entry

//

// Get the entry point for running this method in the interpreter.

address ciMethod::interpreter_entry() {

  check_is_loaded();

  VM_ENTRY_MARK;

  methodHandle mh(THREAD, get_methodOop());

  return Interpreter::entry_for_method(mh);

}

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

// ciMethod::uses_balanced_monitors

//

// Does this method use monitors in a strict stack-disciplined manner?

bool ciMethod::has_balanced_monitors() {

  check_is_loaded();

  if (_balanced_monitors) return true;

  // Analyze the method to see if monitors are used properly.

  VM_ENTRY_MARK;

  methodHandle method(THREAD, get_methodOop());

  assert(method->has_monitor_bytecodes(), "should have checked this");

  // Check to see if a previous compilation computed the

  // monitor-matching analysis.

  if (method->guaranteed_monitor_matching()) {

    _balanced_monitors = true;

    return true;

  }

  {

    EXCEPTION_MARK;

    ResourceMark rm(THREAD);

    GeneratePairingInfo gpi(method);

    gpi.compute_map(CATCH);

    if (!gpi.monitor_safe()) {

      return false;

    }

    method->set_guaranteed_monitor_matching();

    _balanced_monitors = true;

  }

  return true;

}

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

// ciMethod::get_flow_analysis

ciTypeFlow* ciMethod::get_flow_analysis() {

#if defined(COMPILER2) || defined(SHARK)

  if (_flow == NULL) {

    ciEnv* env = CURRENT_ENV;

    _flow = new (env->arena()) ciTypeFlow(env, this);

    _flow->do_flow();

  }

  return _flow;

#else // COMPILER2 || SHARK

  ShouldNotReachHere();

  return NULL;

#endif // COMPILER2 || SHARK

}

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

// ciMethod::get_osr_flow_analysis

ciTypeFlow* ciMethod::get_osr_flow_analysis(int osr_bci) {

#if defined(COMPILER2) || defined(SHARK)

  // OSR entry points are always place after a call bytecode of some sort

  assert(osr_bci >= 0, "must supply valid OSR entry point");

  ciEnv* env = CURRENT_ENV;

  ciTypeFlow* flow = new (env->arena()) ciTypeFlow(env, this, osr_bci);

  flow->do_flow();

  return flow;

#else // COMPILER2 || SHARK

  ShouldNotReachHere();

  return NULL;

#endif // COMPILER2 || SHARK

}

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

// ciMethod::raw_liveness_at_bci

//

// Which local variables are live at a specific bci?

MethodLivenessResult ciMethod::raw_liveness_at_bci(int bci) {

  check_is_loaded();

  if (_liveness == NULL) {

    // Create the liveness analyzer.

    Arena* arena = CURRENT_ENV->arena();

    _liveness = new (arena) MethodLiveness(arena, this);

    _liveness->compute_liveness();

  }

  return _liveness->get_liveness_at(bci);

}

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

// ciMethod::liveness_at_bci

//

// Which local variables are live at a specific bci?  When debugging

// will return true for all locals in some cases to improve debug

// information.

MethodLivenessResult ciMethod::liveness_at_bci(int bci) {

  MethodLivenessResult result = raw_liveness_at_bci(bci);

  if (CURRENT_ENV->jvmti_can_access_local_variables() || DeoptimizeALot || CompileTheWorld) {

    // Keep all locals live for the user's edification and amusement.

    result.at_put_range(0, result.size(), true);

  }

  return result;

}

// ciMethod::live_local_oops_at_bci

//

// find all the live oops in the locals array for a particular bci

// Compute what the interpreter believes by using the interpreter

// oopmap generator. This is used as a double check during osr to

// guard against conservative result from MethodLiveness making us

// think a dead oop is live.  MethodLiveness is conservative in the

// sense that it may consider locals to be live which cannot be live,

// like in the case where a local could contain an oop or  a primitive

// along different paths.  In that case the local must be dead when

// those paths merge. Since the interpreter's viewpoint is used when

// gc'ing an interpreter frame we need to use its viewpoint  during

// OSR when loading the locals.

BitMap ciMethod::live_local_oops_at_bci(int bci) {

  VM_ENTRY_MARK;

  InterpreterOopMap mask;

  OopMapCache::compute_one_oop_map(get_methodOop(), bci, &mask);

  int mask_size = max_locals();

  BitMap result(mask_size);

  result.clear();

  int i;

  for (i = 0; i < mask_size ; i++ ) {

    if (mask.is_oop(i)) result.set_bit(i);

  }

  return result;

}

#ifdef COMPILER1

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

// ciMethod::bci_block_start

//

// Marks all bcis where a new basic block starts

const BitMap ciMethod::bci_block_start() {

  check_is_loaded();

  if (_liveness == NULL) {

    // Create the liveness analyzer.

    Arena* arena = CURRENT_ENV->arena();

    _liveness = new (arena) MethodLiveness(arena, this);

    _liveness->compute_liveness();

  }

  return _liveness->get_bci_block_start();

}

#endif // COMPILER1

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

// ciMethod::call_profile_at_bci

//

// Get the ciCallProfile for the invocation of this method.

// Also reports receiver types for non-call type checks (if TypeProfileCasts).

ciCallProfile ciMethod::call_profile_at_bci(int bci) {

  ResourceMark rm;

  ciCallProfile result;

  if (method_data() != NULL && method_data()->is_mature()) {

    ciProfileData* data = method_data()->bci_to_data(bci);

    if (data != NULL && data->is_CounterData()) {

      // Every profiled call site has a counter.

      int count = data->as_CounterData()->count();

      if (!data->is_ReceiverTypeData()) {

        result._receiver_count[0] = 0;  // that's a definite zero

      } else { // ReceiverTypeData is a subclass of CounterData

        ciReceiverTypeData* call = (ciReceiverTypeData*)data->as_ReceiverTypeData();

        // In addition, virtual call sites have receiver type information

        int receivers_count_total = 0;

        int morphism = 0;

        // Precompute morphism for the possible fixup

        for (uint i = 0; i < call->row_limit(); i++) {

          ciKlass* receiver = call->receiver(i);

          if (receiver == NULL)  continue;

          morphism++;

        }

        int epsilon = 0;

        if (TieredCompilation && ProfileInterpreter) {

          // Interpreter and C1 treat final and special invokes differently.

          // C1 will record a type, whereas the interpreter will just

          // increment the count. Detect this case.

          if (morphism == 1 && count > 0) {

            epsilon = count;

            count = 0;

          }

        }

        for (uint i = 0; i < call->row_limit(); i++) {

          ciKlass* receiver = call->receiver(i);

          if (receiver == NULL)  continue;

          int rcount = call->receiver_count(i) + epsilon;

          if (rcount == 0) rcount = 1; // Should be valid value

          receivers_count_total += rcount;

          // Add the receiver to result data.

          result.add_receiver(receiver, rcount);

          // If we extend profiling to record methods,

          // we will set result._method also.

        }

        // Determine call site's morphism.

        // The call site count is 0 with known morphism (onlt 1 or 2 receivers)

        // or < 0 in the case of a type check failured for checkcast, aastore, instanceof.

        // The call site count is > 0 in the case of a polymorphic virtual call.

        if (morphism > 0 && morphism == result._limit) {

           // The morphism <= MorphismLimit.

           if ((morphism <  ciCallProfile::MorphismLimit) ||

               (morphism == ciCallProfile::MorphismLimit && count == 0)) {

#ifdef ASSERT

             if (count > 0) {

               this->print_short_name(tty);

               tty->print_cr(" @ bci:%d", bci);

               this->print_codes();

               assert(false, "this call site should not be polymorphic");

             }

#endif