C++ Method::is_native方法代码示例

/*
 * Get Method Modifiers
 *
 * For the method indicated by method, return the access flags
 * via modifiers_ptr.
 *
 * REQUIRED Functionality.
 */
jvmtiError JNICALL
jvmtiGetMethodModifiers(jvmtiEnv* env,
                        jmethodID method,
                        jint* modifiers_ptr)
{
    TRACE("GetMethodModifiers called");
    SuspendEnabledChecker sec;
    /*
     * Check given env & current phase.
     */
    jvmtiPhase phases[] = {JVMTI_PHASE_START, JVMTI_PHASE_LIVE};

    CHECK_EVERYTHING();

    if( !method ) return JVMTI_ERROR_NULL_POINTER;
    if( !modifiers_ptr ) return JVMTI_ERROR_NULL_POINTER;

    *modifiers_ptr = 0;
    Method* mtd = reinterpret_cast<Method*>(method);
    if( mtd->is_public() ) *modifiers_ptr |= ACC_PUBLIC;
    if( mtd->is_private() ) *modifiers_ptr |= ACC_PRIVATE;
    if( mtd->is_protected() ) *modifiers_ptr |= ACC_PROTECTED;
    if( mtd->is_static() ) *modifiers_ptr |= ACC_STATIC;
    if( mtd->is_final() ) *modifiers_ptr |= ACC_FINAL;
    if( mtd->is_synchronized() ) *modifiers_ptr |= ACC_SYNCHRONIZED;
    if( mtd->is_native() ) *modifiers_ptr |= ACC_NATIVE;
    if( mtd->is_abstract() ) *modifiers_ptr |= ACC_ABSTRACT;

    return JVMTI_ERROR_NONE;
}

void javaVFrame::print_value() const {
  Method*    m = method();
  InstanceKlass*     k = m->method_holder();
  tty->print_cr("frame( sp=" INTPTR_FORMAT ", unextended_sp=" INTPTR_FORMAT ", fp=" INTPTR_FORMAT ", pc=" INTPTR_FORMAT ")",
                _fr.sp(),  _fr.unextended_sp(), _fr.fp(), _fr.pc());
  tty->print("%s.%s", k->internal_name(), m->name()->as_C_string());

  if (!m->is_native()) {
    Symbol*  source_name = k->source_file_name();
    int        line_number = m->line_number_from_bci(bci());
    if (source_name != NULL && (line_number != -1)) {
      tty->print("(%s:%d)", source_name->as_C_string(), line_number);
    }
  } else {
    tty->print("(Native Method)");
  }
  // Check frame size and print warning if it looks suspiciously large
  if (fr().sp() != NULL) {
    RegisterMap map = *register_map();
    uint size = fr().frame_size(&map);
#ifdef _LP64
    if (size > 8*K) warning("SUSPICIOUSLY LARGE FRAME (%d)", size);
#else
    if (size > 4*K) warning("SUSPICIOUSLY LARGE FRAME (%d)", size);
#endif
  }
}

/*
 * Get Bytecodes
 *
 * For the method indicated by method, return the byte codes that
 * implement the method. The number of bytecodes is returned via
 * bytecode_count_ptr. The byte codes themselves are returned via
 * bytecodes_ptr.
 *
 * OPTIONAL Functionality.
 */
jvmtiError JNICALL
jvmtiGetBytecodes(jvmtiEnv* env,
                  jmethodID method,
                  jint* bytecode_count_ptr,
                  unsigned char** bytecodes_ptr)
{
    TRACE("GetBytecodes called");
    SuspendEnabledChecker sec;
    /*
     * Check given env & current phase.
     */
    jvmtiPhase phases[] = {JVMTI_PHASE_START, JVMTI_PHASE_LIVE};

    CHECK_EVERYTHING();

    CHECK_CAPABILITY(can_get_bytecodes);

    /**
     * Check is_native_ptr
     */
    if( !bytecode_count_ptr || !bytecodes_ptr ) {
        return JVMTI_ERROR_NULL_POINTER;
    }
    /**
     * Check method
     */
    if( !method ) {
        return JVMTI_ERROR_INVALID_METHODID;
    }

    Method* mtd = (Method*)method;
    if( mtd->is_native() ) return JVMTI_ERROR_NATIVE_METHOD;
    if( mtd->get_byte_code_addr() == NULL ) return JVMTI_ERROR_OUT_OF_MEMORY;

    *bytecode_count_ptr = mtd->get_byte_code_size();
    jvmtiError err = _allocate( *bytecode_count_ptr, bytecodes_ptr );
    if( err != JVMTI_ERROR_NONE ) return err;
    memcpy( *bytecodes_ptr, mtd->get_byte_code_addr(), *bytecode_count_ptr );

    if (interpreter_enabled())
    {
        TIEnv *p_env = (TIEnv *)env;
        VMBreakPoints* vm_brpt = p_env->vm->vm_env->TI->vm_brpt;

        LMAutoUnlock lock(vm_brpt->get_lock());

        for (VMBreakPoint* bpt = vm_brpt->find_method_breakpoint(method); bpt;
             bpt = vm_brpt->find_next_method_breakpoint(bpt, method))
        {
            (*bytecodes_ptr)[bpt->location] =
                (unsigned char)bpt->saved_byte;
        }
    }

    return JVMTI_ERROR_NONE;
}

BasicType frame::interpreter_frame_result(oop* oop_result,
                                          jvalue* value_result) {
  assert(is_interpreted_frame(), "interpreted frame expected");
  Method* method = interpreter_frame_method();
  BasicType type = method->result_type();
  intptr_t* tos_addr = (intptr_t *) interpreter_frame_tos_address();
  oop obj;

  switch (type) {
  case T_VOID:
    break;
  case T_BOOLEAN:
    value_result->z = *(jboolean *) tos_addr;
    break;
  case T_BYTE:
    value_result->b = *(jbyte *) tos_addr;
    break;
  case T_CHAR:
    value_result->c = *(jchar *) tos_addr;
    break;
  case T_SHORT:
    value_result->s = *(jshort *) tos_addr;
    break;
  case T_INT:
    value_result->i = *(jint *) tos_addr;
    break;
  case T_LONG:
    value_result->j = *(jlong *) tos_addr;
    break;
  case T_FLOAT:
    value_result->f = *(jfloat *) tos_addr;
    break;
  case T_DOUBLE:
    value_result->d = *(jdouble *) tos_addr;
    break;

  case T_OBJECT:
  case T_ARRAY:
    if (method->is_native()) {
      obj = get_interpreterState()->oop_temp();
    }
    else {
      oop* obj_p = (oop *) tos_addr;
      obj = (obj_p == NULL) ? (oop) NULL : *obj_p;
    }
    assert(obj == NULL || Universe::heap()->is_in(obj), "sanity check");
    *oop_result = obj;
    break;

  default:
    ShouldNotReachHere();
  }

  return type;
}

BasicType frame::interpreter_frame_result(oop* oop_result, jvalue* value_result) {
  assert(is_interpreted_frame(), "interpreted frame expected");
  Method* method = interpreter_frame_method();
  BasicType type = method->result_type();

  if (method->is_native()) {
    // Prior to calling into the runtime to notify the method exit the possible
    // result value is saved into the interpreter frame.
    address lresult = (address)&(get_ijava_state()->lresult);
    address fresult = (address)&(get_ijava_state()->fresult);

    switch (method->result_type()) {
      case T_OBJECT:
      case T_ARRAY: {
        *oop_result = JNIHandles::resolve(*(jobject*)lresult);
        break;
      }
      // We use std/stfd to store the values.
      case T_BOOLEAN : value_result->z = (jboolean) *(unsigned long*)lresult; break;
      case T_INT     : value_result->i = (jint)     *(long*)lresult;          break;
      case T_CHAR    : value_result->c = (jchar)    *(unsigned long*)lresult; break;
      case T_SHORT   : value_result->s = (jshort)   *(long*)lresult;          break;
      case T_BYTE    : value_result->z = (jbyte)    *(long*)lresult;          break;
      case T_LONG    : value_result->j = (jlong)    *(long*)lresult;          break;
      case T_FLOAT   : value_result->f = (jfloat)   *(double*)fresult;        break;
      case T_DOUBLE  : value_result->d = (jdouble)  *(double*)fresult;        break;
      case T_VOID    : /* Nothing to do */ break;
      default        : ShouldNotReachHere();
    }
  } else {
    intptr_t* tos_addr = interpreter_frame_tos_address();
    switch (method->result_type()) {
      case T_OBJECT:
      case T_ARRAY: {
        oop obj = *(oop*)tos_addr;
        assert(obj == NULL || Universe::heap()->is_in(obj), "sanity check");
        *oop_result = obj;
      }
      case T_BOOLEAN : value_result->z = (jboolean) *(jint*)tos_addr; break;
      case T_BYTE    : value_result->b = (jbyte) *(jint*)tos_addr; break;
      case T_CHAR    : value_result->c = (jchar) *(jint*)tos_addr; break;
      case T_SHORT   : value_result->s = (jshort) *(jint*)tos_addr; break;
      case T_INT     : value_result->i = *(jint*)tos_addr; break;
      case T_LONG    : value_result->j = *(jlong*)tos_addr; break;
      case T_FLOAT   : value_result->f = *(jfloat*)tos_addr; break;
      case T_DOUBLE  : value_result->d = *(jdouble*)tos_addr; break;
      case T_VOID    : /* Nothing to do */ break;
      default        : ShouldNotReachHere();
    }
  }
  return type;
}

void ncai_report_method_exit(jmethodID method, jboolean exc_popped, jvalue ret_val)
{
    GlobalNCAI* ncai = VM_Global_State::loader_env->NCAI;

    if (!GlobalNCAI::isEnabled())
        return;

    assert(method);

    Method* m = reinterpret_cast<Method*>(method);
    bool is_native = m->is_native();

    if (is_native && ncai->step_enabled)
        ncai_step_native_method_exit(m);
}

GrowableArray<MonitorInfo*>* compiledVFrame::monitors() const {
  // Natives has no scope
  if (scope() == NULL) {
    nmethod* nm = code();
    Method* method = nm->method();
    assert(method->is_native(), "");
    if (!method->is_synchronized()) {
      return new GrowableArray<MonitorInfo*>(0);
    }
    // This monitor is really only needed for UseBiasedLocking, but
    // return it in all cases for now as it might be useful for stack
    // traces and tools as well
    GrowableArray<MonitorInfo*> *monitors = new GrowableArray<MonitorInfo*>(1);
    // Casting away const
    frame& fr = (frame&) _fr;
    MonitorInfo* info = new MonitorInfo(
        fr.get_native_receiver(), fr.get_native_monitor(), false, false);
    monitors->push(info);
    return monitors;
  }
  GrowableArray<MonitorValue*>* monitors = scope()->monitors();
  if (monitors == NULL) {
    return new GrowableArray<MonitorInfo*>(0);
  }
  GrowableArray<MonitorInfo*>* result = new GrowableArray<MonitorInfo*>(monitors->length());
  for (int index = 0; index < monitors->length(); index++) {
    MonitorValue* mv = monitors->at(index);
    ScopeValue*   ov = mv->owner();
    StackValue *owner_sv = create_stack_value(ov); // it is an oop
    if (ov->is_object() && owner_sv->obj_is_scalar_replaced()) { // The owner object was scalar replaced
      assert(mv->eliminated(), "monitor should be eliminated for scalar replaced object");
      // Put klass for scalar replaced object.
      ScopeValue* kv = ((ObjectValue *)ov)->klass();
      assert(kv->is_constant_oop(), "klass should be oop constant for scalar replaced object");
      Handle k(((ConstantOopReadValue*)kv)->value()());
      assert(java_lang_Class::is_instance(k()), "must be");
      result->push(new MonitorInfo(k(), resolve_monitor_lock(mv->basic_lock()),
                                   mv->eliminated(), true));
    } else {
      result->push(new MonitorInfo(owner_sv->get_obj()(), resolve_monitor_lock(mv->basic_lock()),
                                   mv->eliminated(), false));
    }
  }
  return result;
}

jvmtiError
JvmtiEnvBase::get_frame_location(JavaThread *java_thread, jint depth,
                                 jmethodID* method_ptr, jlocation* location_ptr) {
#ifdef ASSERT
  uint32_t debug_bits = 0;
#endif
  assert((SafepointSynchronize::is_at_safepoint() ||
          is_thread_fully_suspended(java_thread, false, &debug_bits)),
         "at safepoint or target thread is suspended");
  Thread* current_thread = Thread::current();
  ResourceMark rm(current_thread);

  vframe *vf = vframeFor(java_thread, depth);
  if (vf == NULL) {
    return JVMTI_ERROR_NO_MORE_FRAMES;
  }

  // vframeFor should return a java frame. If it doesn't
  // it means we've got an internal error and we return the
  // error in product mode. In debug mode we will instead
  // attempt to cast the vframe to a javaVFrame and will
  // cause an assertion/crash to allow further diagnosis.
#ifdef PRODUCT
  if (!vf->is_java_frame()) {
    return JVMTI_ERROR_INTERNAL;
  }
#endif

  HandleMark hm(current_thread);
  javaVFrame *jvf = javaVFrame::cast(vf);
  Method* method = jvf->method();
  if (method->is_native()) {
    *location_ptr = -1;
  } else {
    *location_ptr = jvf->bci();
  }
  *method_ptr = method->jmethod_id();

  return JVMTI_ERROR_NONE;
}

BasicType frame::interpreter_frame_result(oop* oop_result, jvalue* value_result) {
#ifdef CC_INTERP
  // Needed for JVMTI. The result should always be in the
  // interpreterState object
  interpreterState istate = get_interpreterState();
#endif // CC_INTERP
  assert(is_interpreted_frame(), "interpreted frame expected");
  Method* method = interpreter_frame_method();
  BasicType type = method->result_type();

  intptr_t* tos_addr;
  if (method->is_native()) {
    // Prior to calling into the runtime to report the method_exit the possible
    // return value is pushed to the native stack. If the result is a jfloat/jdouble
    // then ST0 is saved before EAX/EDX. See the note in generate_native_result
    tos_addr = (intptr_t*)sp();
    if (type == T_FLOAT || type == T_DOUBLE) {
    // QQQ seems like this code is equivalent on the two platforms
#ifdef AMD64
      // This is times two because we do a push(ltos) after pushing XMM0
      // and that takes two interpreter stack slots.
      tos_addr += 2 * Interpreter::stackElementWords;
#else
      tos_addr += 2;
#endif // AMD64
    }
  } else {
    tos_addr = (intptr_t*)interpreter_frame_tos_address();
  }

  switch (type) {
    case T_OBJECT  :
    case T_ARRAY   : {
      oop obj;
      if (method->is_native()) {
#ifdef CC_INTERP
        obj = istate->_oop_temp;
#else
        obj = cast_to_oop(at(interpreter_frame_oop_temp_offset));
#endif // CC_INTERP
      } else {
        oop* obj_p = (oop*)tos_addr;
        obj = (obj_p == NULL) ? (oop)NULL : *obj_p;
      }
      assert(obj == NULL || Universe::heap()->is_in(obj), "sanity check");
      *oop_result = obj;
      break;
    }
    case T_BOOLEAN : value_result->z = *(jboolean*)tos_addr; break;
    case T_BYTE    : value_result->b = *(jbyte*)tos_addr; break;
    case T_CHAR    : value_result->c = *(jchar*)tos_addr; break;
    case T_SHORT   : value_result->s = *(jshort*)tos_addr; break;
    case T_INT     : value_result->i = *(jint*)tos_addr; break;
    case T_LONG    : value_result->j = *(jlong*)tos_addr; break;
    case T_FLOAT   : {
#ifdef AMD64
        value_result->f = *(jfloat*)tos_addr;
#else
      if (method->is_native()) {
        jdouble d = *(jdouble*)tos_addr;  // Result was in ST0 so need to convert to jfloat
        value_result->f = (jfloat)d;
      } else {
        value_result->f = *(jfloat*)tos_addr;
      }
#endif // AMD64
      break;
    }
    case T_DOUBLE  : value_result->d = *(jdouble*)tos_addr; break;
    case T_VOID    : /* Nothing to do */ break;
    default        : ShouldNotReachHere();
  }

  return type;
}

BasicType frame::interpreter_frame_result(oop* oop_result, jvalue* value_result) {
  assert(is_interpreted_frame(), "interpreted frame expected");
  Method* method = interpreter_frame_method();
  BasicType type = method->result_type();

  if (method->is_native()) {
    // Prior to notifying the runtime of the method_exit the possible result
    // value is saved to l_scratch and d_scratch.

#ifdef CC_INTERP
    interpreterState istate = get_interpreterState();
    intptr_t* l_scratch = (intptr_t*) &istate->_native_lresult;
    intptr_t* d_scratch = (intptr_t*) &istate->_native_fresult;
#else /* CC_INTERP */
    intptr_t* l_scratch = fp() + interpreter_frame_l_scratch_fp_offset;
    intptr_t* d_scratch = fp() + interpreter_frame_d_scratch_fp_offset;
#endif /* CC_INTERP */

    address l_addr = (address)l_scratch;
#ifdef _LP64
    // On 64-bit the result for 1/8/16/32-bit result types is in the other
    // word half
    l_addr += wordSize/2;
#endif

    switch (type) {
      case T_OBJECT:
      case T_ARRAY: {
#ifdef CC_INTERP
        *oop_result = istate->_oop_temp;
#else
        oop obj = cast_to_oop(at(interpreter_frame_oop_temp_offset));
        assert(obj == NULL || Universe::heap()->is_in(obj), "sanity check");
        *oop_result = obj;
#endif // CC_INTERP
        break;
      }

      case T_BOOLEAN : { jint* p = (jint*)l_addr; value_result->z = (jboolean)((*p) & 0x1); break; }
      case T_BYTE    : { jint* p = (jint*)l_addr; value_result->b = (jbyte)((*p) & 0xff); break; }
      case T_CHAR    : { jint* p = (jint*)l_addr; value_result->c = (jchar)((*p) & 0xffff); break; }
      case T_SHORT   : { jint* p = (jint*)l_addr; value_result->s = (jshort)((*p) & 0xffff); break; }
      case T_INT     : value_result->i = *(jint*)l_addr; break;
      case T_LONG    : value_result->j = *(jlong*)l_scratch; break;
      case T_FLOAT   : value_result->f = *(jfloat*)d_scratch; break;
      case T_DOUBLE  : value_result->d = *(jdouble*)d_scratch; break;
      case T_VOID    : /* Nothing to do */ break;
      default        : ShouldNotReachHere();
    }
  } else {
    intptr_t* tos_addr = interpreter_frame_tos_address();

    switch(type) {
      case T_OBJECT:
      case T_ARRAY: {
        oop obj = cast_to_oop(*tos_addr);
        assert(obj == NULL || Universe::heap()->is_in(obj), "sanity check");
        *oop_result = obj;
        break;
      }
      case T_BOOLEAN : { jint* p = (jint*)tos_addr; value_result->z = (jboolean)((*p) & 0x1); break; }
      case T_BYTE    : { jint* p = (jint*)tos_addr; value_result->b = (jbyte)((*p) & 0xff); break; }
      case T_CHAR    : { jint* p = (jint*)tos_addr; value_result->c = (jchar)((*p) & 0xffff); break; }
      case T_SHORT   : { jint* p = (jint*)tos_addr; value_result->s = (jshort)((*p) & 0xffff); break; }
      case T_INT     : value_result->i = *(jint*)tos_addr; break;
      case T_LONG    : value_result->j = *(jlong*)tos_addr; break;
      case T_FLOAT   : value_result->f = *(jfloat*)tos_addr; break;
      case T_DOUBLE  : value_result->d = *(jdouble*)tos_addr; break;
      case T_VOID    : /* Nothing to do */ break;
      default        : ShouldNotReachHere();
    }
  };

  return type;
}

static inline Boolean
interp_si_method_is_native(Method_Handle m) {
    assert(m);
    Method *meth = (Method *)m;
    return meth->is_native();
}

void
interp_ti_enumerate_root_set_single_thread_on_stack(jvmtiEnv* ti_env, VM_thread *thread) {
    TRACE2("enumeration", "interp_enumerate_root_set_single_thread_on_stack()");
    StackIterator_interp* si;
    si = interp_si_create_from_native(thread);
    
    int i;
    int depth;
    DEBUG_GC("\n\nGC enumeration in interpreter stack:\n");
    for (depth = 0; !interp_si_is_past_end(si); depth++) {
        Method* method = (Method*)interp_si_get_method(si);
        jmethodID method_id = (jmethodID)method;
        int slot = 0;

        if (si->This) {
            vm_ti_enumerate_stack_root(ti_env,
                    (void**)&si->This, si->This,
                    JVMTI_HEAP_ROOT_STACK_LOCAL,
                    depth, method_id, slot++);
            DEBUG_GC("  [THIS]: " << si->This);
        }

        if (si->exc) {
            vm_ti_enumerate_stack_root(ti_env,
                (void**)&si->exc, si->exc,
                JVMTI_HEAP_ROOT_STACK_LOCAL,
                depth, method_id, slot++);
            DEBUG_GC("  [EXCEPTION]: " << si->exc);
        }

        if (method->is_native()) {
            DEBUG_GC("[METHOD <native>]: " << method);
            interp_si_goto_previous(si);
            continue;
        }

        DEBUG_GC("[METHOD "<< si->stack.size << " " << (int)si->locals.varNum << "]: "
                << method);

        if (si->stack.size)
            for(i = 0; i <= si->stack.index; i++) {
                if (si->stack.refs[i] == FLAG_OBJECT) {
                    DEBUG_GC("  Stack[" << i << "] ");
                    REF* ref = &si->stack.data[i].ref;
                    ManagedObject *obj = UNCOMPRESS_INTERP(*ref);
                    if (obj == 0) {
                        DEBUG_GC("NULL");
                    } else {
                        DEBUG_GC(obj);
                        vm_ti_enumerate_stack_root(ti_env,
                            ref, (Managed_Object_Handle)obj, 
                            JVMTI_HEAP_ROOT_STACK_LOCAL,
                            depth, method_id, slot++);
                    }
                }
            }

                unsigned j;
        if (si->locals.varNum)
            for(j = 0; j < si->locals.varNum; j++) {
                if (si->locals.refs[j] == FLAG_OBJECT) {
                    DEBUG_GC("  Locals[" << j << "] ");
                    REF* ref = &si->locals.vars[j].ref;
                    ManagedObject *obj = UNCOMPRESS_INTERP(*ref);
                    if (obj == 0) {
                        DEBUG_GC("NULL\n");
                    } else {
                        DEBUG_GC(obj);
                        vm_ti_enumerate_stack_root(ti_env,
                            ref, (Managed_Object_Handle)obj, 
                            JVMTI_HEAP_ROOT_STACK_LOCAL,
                            depth, method_id, slot++);
                    }
                }
            }
        MonitorList *ml = si->locked_monitors;
        while(ml) {
            vm_ti_enumerate_stack_root(ti_env,
                    &ml->monitor, ml->monitor,
                    JVMTI_HEAP_ROOT_MONITOR,
                    depth, method_id, slot++);
            ml = ml->next;
        }
        interp_si_goto_previous(si);
    }

    // enumerate m2n frames
    M2nFrame *m2n = m2n_get_last_frame(thread);
    while(m2n) {
        oh_enumerate_handles(m2n_get_local_handles(m2n));
        m2n = m2n_get_previous_frame(m2n);
    }
}

static void forte_fill_call_trace_given_top(JavaThread* thd,
                                            ASGCT_CallTrace* trace,
                                            int depth,
                                            frame top_frame) {
  NoHandleMark nhm;

  frame initial_Java_frame;
  Method* method;
  int bci;
  int count;

  count = 0;
  assert(trace->frames != NULL, "trace->frames must be non-NULL");

  bool fully_decipherable = find_initial_Java_frame(thd, &top_frame, &initial_Java_frame, &method, &bci);

  // The frame might not be walkable but still recovered a method
  // (e.g. an nmethod with no scope info for the pc)

  if (method == NULL) return;

  if (!method->is_valid_method()) {
    trace->num_frames = ticks_GC_active; // -2
    return;
  }

  // We got a Java frame however it isn't fully decipherable
  // so it won't necessarily be safe to use it for the
  // initial frame in the vframe stream.

  if (!fully_decipherable) {
    // Take whatever method the top-frame decoder managed to scrape up.
    // We look further at the top frame only if non-safepoint
    // debugging information is available.
    count++;
    trace->num_frames = count;
    trace->frames[0].method_id = method->find_jmethod_id_or_null();
    if (!method->is_native()) {
      trace->frames[0].lineno = bci;
    } else {
      trace->frames[0].lineno = -3;
    }

    if (!initial_Java_frame.safe_for_sender(thd)) return;

    RegisterMap map(thd, false);
    initial_Java_frame = initial_Java_frame.sender(&map);
  }

  vframeStreamForte st(thd, initial_Java_frame, false);

  for (; !st.at_end() && count < depth; st.forte_next(), count++) {
    bci = st.bci();
    method = st.method();

    if (!method->is_valid_method()) {
      // we throw away everything we've gathered in this sample since
      // none of it is safe
      trace->num_frames = ticks_GC_active; // -2
      return;
    }

    trace->frames[count].method_id = method->find_jmethod_id_or_null();
    if (!method->is_native()) {
      trace->frames[count].lineno = bci;
    } else {
      trace->frames[count].lineno = -3;
    }
  }
  trace->num_frames = count;
  return;
}