/*

 * Copyright (c) 1997, 2018, 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 "gc/shared/collectedHeap.hpp"

#include "gc/shared/collectedHeap.inline.hpp"

#include "memory/resourceArea.hpp"

#include "runtime/atomic.hpp"

#include "runtime/frame.inline.hpp"

#include "runtime/handles.inline.hpp"

#include "runtime/init.hpp"

#include "runtime/interfaceSupport.inline.hpp"

#include "runtime/orderAccess.hpp"

#include "runtime/os.inline.hpp"

#include "runtime/thread.inline.hpp"

#include "runtime/safepointVerifiers.hpp"

#include "runtime/vframe.hpp"

#include "runtime/vmThread.hpp"

#include "utilities/preserveException.hpp"

// Implementation of InterfaceSupport

#ifdef ASSERT

VMEntryWrapper::VMEntryWrapper() {

  if (VerifyLastFrame) {

    InterfaceSupport::verify_last_frame();

  }

}

VMEntryWrapper::~VMEntryWrapper() {

  InterfaceSupport::check_gc_alot();

  if (WalkStackALot) {

    InterfaceSupport::walk_stack();

  }

#ifdef COMPILER2

  // This option is not used by Compiler 1

  if (StressDerivedPointers) {

    InterfaceSupport::stress_derived_pointers();

  }

#endif

  if (DeoptimizeALot || DeoptimizeRandom) {

    InterfaceSupport::deoptimizeAll();

  }

  if (ZombieALot) {

    InterfaceSupport::zombieAll();

  }

  if (UnlinkSymbolsALot) {

    InterfaceSupport::unlinkSymbols();

  }

  // do verification AFTER potential deoptimization

  if (VerifyStack) {

    InterfaceSupport::verify_stack();

  }

}

long InterfaceSupport::_number_of_calls       = 0;

long InterfaceSupport::_scavenge_alot_counter = 1;

long InterfaceSupport::_fullgc_alot_counter   = 1;

long InterfaceSupport::_fullgc_alot_invocation = 0;

Histogram* RuntimeHistogram;

RuntimeHistogramElement::RuntimeHistogramElement(const char* elementName) {

  static volatile int RuntimeHistogram_lock = 0;

  _name = elementName;

  uintx count = 0;

  while (Atomic::cmpxchg(1, &RuntimeHistogram_lock, 0) != 0) {

    while (OrderAccess::load_acquire(&RuntimeHistogram_lock) != 0) {

      count +=1;

      if ( (WarnOnStalledSpinLock > 0)

        && (count % WarnOnStalledSpinLock == 0)) {

        warning("RuntimeHistogram_lock seems to be stalled");

      }

    }

  }

  if (RuntimeHistogram == NULL) {

    RuntimeHistogram = new Histogram("VM Runtime Call Counts",200);

  }

  RuntimeHistogram->add_element(this);

  Atomic::dec(&RuntimeHistogram_lock);

}

void InterfaceSupport::gc_alot() {

  Thread *thread = Thread::current();

  if (!thread->is_Java_thread()) return; // Avoid concurrent calls

  // Check for new, not quite initialized thread. A thread in new mode cannot initiate a GC.

  JavaThread *current_thread = (JavaThread *)thread;

  if (current_thread->active_handles() == NULL) return;

  // Short-circuit any possible re-entrant gc-a-lot attempt

  if (thread->skip_gcalot()) return;

  if (Threads::is_vm_complete()) {

    if (++_fullgc_alot_invocation < FullGCALotStart) {

      return;

    }

    // Use this line if you want to block at a specific point,

    // e.g. one number_of_calls/scavenge/gc before you got into problems

    if (FullGCALot) _fullgc_alot_counter--;

    // Check if we should force a full gc

    if (_fullgc_alot_counter == 0) {

      // Release dummy so objects are forced to move

      if (!Universe::release_fullgc_alot_dummy()) {

        warning("FullGCALot: Unable to release more dummies at bottom of heap");

      }

      HandleMark hm(thread);

      Universe::heap()->collect(GCCause::_full_gc_alot);

      unsigned int invocations = Universe::heap()->total_full_collections();

      // Compute new interval

      if (FullGCALotInterval > 1) {

        _fullgc_alot_counter = 1+(long)((double)FullGCALotInterval*os::random()/(max_jint+1.0));

        log_trace(gc)("Full gc no: %u\tInterval: %ld", invocations, _fullgc_alot_counter);

      } else {

        _fullgc_alot_counter = 1;

      }

      // Print progress message

      if (invocations % 100 == 0) {

        log_trace(gc)("Full gc no: %u", invocations);

      }

    } else {

      if (ScavengeALot) _scavenge_alot_counter--;

      // Check if we should force a scavenge

      if (_scavenge_alot_counter == 0) {

        HandleMark hm(thread);

        Universe::heap()->collect(GCCause::_scavenge_alot);

        unsigned int invocations = Universe::heap()->total_collections() - Universe::heap()->total_full_collections();

        // Compute new interval

        if (ScavengeALotInterval > 1) {

          _scavenge_alot_counter = 1+(long)((double)ScavengeALotInterval*os::random()/(max_jint+1.0));

          log_trace(gc)("Scavenge no: %u\tInterval: %ld", invocations, _scavenge_alot_counter);

        } else {

          _scavenge_alot_counter = 1;

        }

        // Print progress message

        if (invocations % 1000 == 0) {

          log_trace(gc)("Scavenge no: %u", invocations);

        }

      }

    }

  }

}

vframe* vframe_array[50];

int walk_stack_counter = 0;

void InterfaceSupport::walk_stack_from(vframe* start_vf) {

  // walk

  int i = 0;

  for (vframe* f = start_vf; f; f = f->sender() ) {

    if (i < 50) vframe_array[i++] = f;

  }

}

void InterfaceSupport::walk_stack() {

  JavaThread* thread = JavaThread::current();

  walk_stack_counter++;

  if (!thread->has_last_Java_frame()) return;

  ResourceMark rm(thread);

  RegisterMap reg_map(thread);

  walk_stack_from(thread->last_java_vframe(&reg_map));

}

// invocation counter for InterfaceSupport::deoptimizeAll/zombieAll functions

int deoptimizeAllCounter = 0;

int zombieAllCounter = 0;

void InterfaceSupport::zombieAll() {

  // This method is called by all threads when a thread make

  // transition to VM state (for example, runtime calls).

  // Divide number of calls by number of threads to avoid

  // dependence of ZombieAll events frequency on number of threads.

  int value = zombieAllCounter / Threads::number_of_threads();

  if (is_init_completed() && value > ZombieALotInterval) {

    zombieAllCounter = 0;

    VM_ZombieAll op;

    VMThread::execute(&op);

  }

  zombieAllCounter++;

}

void InterfaceSupport::unlinkSymbols() {

  VM_UnlinkSymbols op;

  VMThread::execute(&op);

}

void InterfaceSupport::deoptimizeAll() {

  // This method is called by all threads when a thread make

  // transition to VM state (for example, runtime calls).

  // Divide number of calls by number of threads to avoid

  // dependence of DeoptimizeAll events frequency on number of threads.

  int value = deoptimizeAllCounter / Threads::number_of_threads();

  if (is_init_completed()) {

    if (DeoptimizeALot && value > DeoptimizeALotInterval) {

      deoptimizeAllCounter = 0;

      VM_DeoptimizeAll op;

      VMThread::execute(&op);

    } else if (DeoptimizeRandom && (value & 0x1F) == (os::random() & 0x1F)) {

      VM_DeoptimizeAll op;

      VMThread::execute(&op);

    }

  }

  deoptimizeAllCounter++;

}

void InterfaceSupport::stress_derived_pointers() {

#ifdef COMPILER2

  JavaThread *thread = JavaThread::current();

  if (!is_init_completed()) return;

  ResourceMark rm(thread);

  bool found = false;

  for (StackFrameStream sfs(thread); !sfs.is_done() && !found; sfs.next()) {

    CodeBlob* cb = sfs.current()->cb();

    if (cb != NULL && cb->oop_maps() ) {

      // Find oopmap for current method

      const ImmutableOopMap* map = cb->oop_map_for_return_address(sfs.current()->pc());

      assert(map != NULL, "no oopmap found for pc");

      found = map->has_derived_pointer();

    }

  }

  if (found) {

    // $$$ Not sure what to do here.

    /*

    Scavenge::invoke(0);

    */

  }

#endif

}

void InterfaceSupport::verify_stack() {

  JavaThread* thread = JavaThread::current();

  ResourceMark rm(thread);

  // disabled because it throws warnings that oop maps should only be accessed

  // in VM thread or during debugging

  if (!thread->has_pending_exception()) {

    // verification does not work if there are pending exceptions

    StackFrameStream sfs(thread);

    CodeBlob* cb = sfs.current()->cb();

      // In case of exceptions we might not have a runtime_stub on

      // top of stack, hence, all callee-saved registers are not going

      // to be setup correctly, hence, we cannot do stack verify

    if (cb != NULL && !(cb->is_runtime_stub() || cb->is_uncommon_trap_stub())) return;

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

      sfs.current()->verify(sfs.register_map());

    }

  }

}

void InterfaceSupport::verify_last_frame() {

  JavaThread* thread = JavaThread::current();

  ResourceMark rm(thread);

  RegisterMap reg_map(thread);

  frame fr = thread->last_frame();

  fr.verify(&reg_map);

}

#endif // ASSERT

void InterfaceSupport_init() {

#ifdef ASSERT

  if (ScavengeALot || FullGCALot) {

    srand(ScavengeALotInterval * FullGCALotInterval);

  }

#endif

}

#ifdef ASSERT

// JRT_LEAF rules:

// A JRT_LEAF method may not interfere with safepointing by

//   1) acquiring or blocking on a Mutex or JavaLock - checked

//   2) allocating heap memory - checked

//   3) executing a VM operation - checked

//   4) executing a system call (including malloc) that could block or grab a lock

//   5) invoking GC

//   6) reaching a safepoint

//   7) running too long

// Nor may any method it calls.

JRTLeafVerifier::JRTLeafVerifier()

  : NoSafepointVerifier(true, JRTLeafVerifier::should_verify_GC())

{

}

JRTLeafVerifier::~JRTLeafVerifier()

{

}

bool JRTLeafVerifier::should_verify_GC() {

  switch (JavaThread::current()->thread_state()) {

  case _thread_in_Java:

    // is in a leaf routine, there must be no safepoint.

    return true;

  case _thread_in_native:

    // A native thread is not subject to safepoints.

    // Even while it is in a leaf routine, GC is ok

    return false;

  default:

    // Leaf routines cannot be called from other contexts.

    ShouldNotReachHere();

    return false;

  }

}

#endif // ASSERT