keepStackGCProcessed.cpp

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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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#include "precompiled.hpp"
#include "runtime/safepoint.hpp"
#include "runtime/stackWatermark.inline.hpp"
#include "runtime/stackWatermarkSet.inline.hpp"
#include "runtime/keepStackGCProcessed.hpp"

KeepStackGCProcessedMark::KeepStackGCProcessedMark(JavaThread* jt) :
  _active(true),
  _jt(jt) {
  finish_processing();
  if (!Thread::current()->is_Java_thread()) {
    assert(SafepointSynchronize::is_at_safepoint() && Thread::current()->is_VM_thread(),
           "must be either Java thread or VM thread in a safepoint");
    _active = false;
    return;
  }
  StackWatermark* our_watermark = StackWatermarkSet::get(JavaThread::current(), StackWatermarkKind::gc);
  if (our_watermark == NULL) {
    _active = false;
    return;
  }
  StackWatermark* their_watermark = StackWatermarkSet::get(jt, StackWatermarkKind::gc);
  our_watermark->link_watermark(their_watermark);
}

KeepStackGCProcessedMark::~KeepStackGCProcessedMark() {
  if (!_active) {
    return;
  }
  StackWatermark* our_watermark = StackWatermarkSet::get(JavaThread::current(), StackWatermarkKind::gc);
  our_watermark->link_watermark(NULL);
}

void KeepStackGCProcessedMark::finish_processing() {
  StackWatermarkSet::finish_processing(_jt, NULL /* context */, StackWatermarkKind::gc);
}

#ifdef ASSERT
bool KeepStackGCProcessedMark::stack_is_kept_gc_processed(JavaThread* jt) {
  if (!Thread::current()->is_Java_thread()) {
    assert(SafepointSynchronize::is_at_safepoint() && Thread::current()->is_VM_thread(),
           "must be either Java thread or VM thread in a safepoint");
    return true;
  }
  StackWatermark* our_watermark = StackWatermarkSet::get(JavaThread::current(), StackWatermarkKind::gc);
  if (our_watermark == nullptr) {
    return true;
  }
  StackWatermark* their_watermark = StackWatermarkSet::get(jt, StackWatermarkKind::gc);
  return our_watermark->linked_watermark() == their_watermark;
}
#endif // ASSERT