// For Forte Analyzer AsyncGetCallTrace profiling support - thread is
// currently interrupted by SIGPROF
bool JavaThread::pd_get_top_frame_for_signal_handler(frame* fr_addr,
  void* ucontext, bool isInJava) {

  assert(Thread::current() == this, "caller must be current thread");
  assert(this->is_Java_thread(), "must be JavaThread");

  JavaThread* jt = (JavaThread *)this;

  // If we have a last_Java_frame, then we should use it even if
  // isInJava == true.  It should be more reliable than CONTEXT info.
  if (jt->has_last_Java_frame()) {
    *fr_addr = jt->pd_last_frame();
    return true;
  }

  // At this point, we don't have a last_Java_frame, so
  // we try to glean some information out of the CONTEXT
  // if we were running Java code when SIGPROF came in.
  if (isInJava) {
    CONTEXT* uc = (CONTEXT*)ucontext;

#ifdef AMD64
    intptr_t* ret_fp = (intptr_t*) uc->Rbp;
    intptr_t* ret_sp = (intptr_t*) uc->Rsp;
    ExtendedPC addr = ExtendedPC((address)uc->Rip);
#else
    intptr_t* ret_fp = (intptr_t*) uc->Ebp;
    intptr_t* ret_sp = (intptr_t*) uc->Esp;
    ExtendedPC addr = ExtendedPC((address)uc->Eip);
#endif // AMD64
    if (addr.pc() == NULL || ret_sp == NULL ) {
      // CONTEXT wasn't useful
      return false;
    }

    frame ret_frame(ret_sp, ret_fp, addr.pc());
    if (!ret_frame.safe_for_sender(jt)) {
#ifdef COMPILER2
      // C2 uses ebp as a general register see if NULL fp helps
      frame ret_frame2(ret_sp, NULL, addr.pc());
      if (!ret_frame2.safe_for_sender(jt)) {
        // nothing else to try if the frame isn't good
        return false;
      }
      ret_frame = ret_frame2;
#else
      // nothing else to try if the frame isn't good
      return false;
#endif /* COMPILER2 */
    }
    *fr_addr = ret_frame;
    return true;
  }

  // nothing else to try
  return false;
}
示例#2
0
bool JavaThread::pd_get_top_frame(frame* fr_addr, void* ucontext, bool isInJava) {
  assert(this->is_Java_thread(), "must be JavaThread");
  JavaThread* jt = (JavaThread *)this;

  // If we have a last_Java_frame, then we should use it even if
  // isInJava == true.  It should be more reliable than ucontext info.
  if (jt->has_last_Java_frame() && jt->frame_anchor()->walkable()) {
    *fr_addr = jt->pd_last_frame();
    return true;
  }

  // At this point, we don't have a last_Java_frame, so
  // we try to glean some information out of the ucontext
  // if we were running Java code when SIGPROF came in.
  if (isInJava) {
    ucontext_t* uc = (ucontext_t*) ucontext;

    intptr_t* ret_fp;
    intptr_t* ret_sp;
    ExtendedPC addr = os::Bsd::fetch_frame_from_ucontext(this, uc,
      &ret_sp, &ret_fp);
    if (addr.pc() == NULL || ret_sp == NULL ) {
      // ucontext wasn't useful
      return false;
    }

#if INCLUDE_CDS
    if (UseSharedSpaces && MetaspaceShared::is_in_shared_region(addr.pc(), MetaspaceShared::md)) {
      // In the middle of a trampoline call. Bail out for safety.
      // This happens rarely so shouldn't affect profiling.
      return false;
    }
#endif

    frame ret_frame(ret_sp, ret_fp, addr.pc());
    if (!ret_frame.safe_for_sender(jt)) {
#if defined(COMPILER2) || INCLUDE_JVMCI
      // C2 and JVMCI use ebp as a general register see if NULL fp helps
      frame ret_frame2(ret_sp, NULL, addr.pc());
      if (!ret_frame2.safe_for_sender(jt)) {
        // nothing else to try if the frame isn't good
        return false;
      }
      ret_frame = ret_frame2;
#else
      // nothing else to try if the frame isn't good
      return false;
#endif /* COMPILER2 || INCLUDE_JVMCI */
    }
    *fr_addr = ret_frame;
    return true;
  }

  // nothing else to try
  return false;
}
bool JavaThread::pd_get_top_frame(frame* fr_addr, void* ucontext, bool isInJava) {
  assert(this->is_Java_thread(), "must be JavaThread");
  JavaThread* jt = (JavaThread *)this;

  // If we have a last_Java_frame, then we should use it even if
  // isInJava == true.  It should be more reliable than ucontext info.
  if (jt->has_last_Java_frame()) {
    *fr_addr = jt->pd_last_frame();
    return true;
  }

  // At this point, we don't have a last_Java_frame, so
  // we try to glean some information out of the ucontext
  // if we were running Java code when SIGPROF came in.
  if (isInJava) {
    ucontext_t* uc = (ucontext_t*) ucontext;

    intptr_t* ret_fp;
    intptr_t* ret_sp;
    ExtendedPC addr = os::Linux::fetch_frame_from_ucontext(this, uc,
      &ret_sp, &ret_fp);
    if (addr.pc() == NULL || ret_sp == NULL ) {
      // ucontext wasn't useful
      return false;
    }

    frame ret_frame(ret_sp, ret_fp, addr.pc());
    if (!ret_frame.safe_for_sender(jt)) {
#ifdef COMPILER2
      // C2 uses ebp as a general register see if NULL fp helps
      frame ret_frame2(ret_sp, NULL, addr.pc());
      if (!ret_frame2.safe_for_sender(jt)) {
        // nothing else to try if the frame isn't good
        return false;
      }
      ret_frame = ret_frame2;
#else
      // nothing else to try if the frame isn't good
      return false;
#endif /* COMPILER2 */
    }
    *fr_addr = ret_frame;
    return true;
  }

  // nothing else to try
  return false;
}
bool JavaThread::pd_get_top_frame(frame* fr_addr,
  void* ucontext, bool isInJava, bool makeWalkable) {
  assert(this->is_Java_thread(), "must be JavaThread");

  JavaThread* jt = (JavaThread *)this;

  if (!isInJava && makeWalkable) {
    // make_walkable flushes register windows and grabs last_Java_pc
    // which can not be done if the ucontext sp matches last_Java_sp
    // stack walking utilities assume last_Java_pc set if marked flushed
    jt->frame_anchor()->make_walkable(jt);
  }

  // If we have a walkable last_Java_frame, then we should use it
  // even if isInJava == true. It should be more reliable than
  // ucontext info.
  if (jt->has_last_Java_frame() && jt->frame_anchor()->walkable()) {
    *fr_addr = jt->pd_last_frame();
    return true;
  }

  ucontext_t* uc = (ucontext_t*) ucontext;

  // At this point, we don't have a walkable last_Java_frame, so
  // we try to glean some information out of the ucontext.
  intptr_t* ret_sp;
  ExtendedPC addr = os::Solaris::fetch_frame_from_ucontext(this, uc,
    &ret_sp, NULL /* ret_fp only used on Solaris X86 */);
  if (addr.pc() == NULL || ret_sp == NULL) {
    // ucontext wasn't useful
    return false;
  }

#if INCLUDE_CDS
  if (UseSharedSpaces && MetaspaceShared::is_in_shared_region(addr.pc(), MetaspaceShared::md)) {
    // In the middle of a trampoline call. Bail out for safety.
    // This happens rarely so shouldn't affect profiling.
    return false;
  }
#endif

  frame ret_frame(ret_sp, frame::unpatchable, addr.pc());

  // we were running Java code when SIGPROF came in
  if (isInJava) {


    // If the frame we got is safe then it is most certainly valid
    if (ret_frame.safe_for_sender(jt)) {
      *fr_addr = ret_frame;
      return true;
    }

    // If it isn't safe then we can try several things to try and get
    // a good starting point.
    //
    // On sparc the frames are almost certainly walkable in the sense
    // of sp/fp linkages. However because of recycling of windows if
    // a piece of code does multiple save's where the initial save creates
    // a real frame with a return pc and the succeeding save's are used to
    // simply get free registers and have no real pc then the pc linkage on these
    // "inner" temporary frames will be bogus.
    // Since there is in general only a nesting level like
    // this one deep in general we'll try and unwind such an "inner" frame
    // here ourselves and see if it makes sense

    frame unwind_frame(ret_frame.fp(), frame::unpatchable, addr.pc());

    if (unwind_frame.safe_for_sender(jt)) {
      *fr_addr = unwind_frame;
      return true;
    }

    // Well that didn't work. Most likely we're toast on this tick
    // The previous code would try this. I think it is dubious in light
    // of changes to safe_for_sender and the unwind trick above but
    // if it gets us a safe frame who wants to argue.

    // If we have a last_Java_sp, then the SIGPROF signal caught us
    // right when we were transitioning from _thread_in_Java to a new
    // JavaThreadState. We use last_Java_sp instead of the sp from
    // the ucontext since it should be more reliable.

    if (jt->has_last_Java_frame()) {
      ret_sp = jt->last_Java_sp();
      frame ret_frame2(ret_sp, frame::unpatchable, addr.pc());
      if (ret_frame2.safe_for_sender(jt)) {
        *fr_addr = ret_frame2;
        return true;
      }
    }

    // This is the best we can do. We will only be able to decode the top frame

    *fr_addr = ret_frame;
    return true;
  }

  // At this point, we know we weren't running Java code. We might
  // have a last_Java_sp, but we don't have a walkable frame.
  // However, we might still be able to construct something useful
  // if the thread was running native code.
  if (jt->has_last_Java_frame()) {
    assert(!jt->frame_anchor()->walkable(), "case covered above");

    frame ret_frame(jt->last_Java_sp(), frame::unpatchable, addr.pc());
    *fr_addr = ret_frame;
    return true;
  }

  // nothing else to try but what we found initially

  *fr_addr = ret_frame;
  return true;
}