{-# LANGUAGE NoImplicitPrelude #-}

-- | Module with fewer dependencies than GHC.Internal.RTS.Flags
-- that allows to quickly test if some flag is set.
module GHC.Internal.RTS.Flags.Test
  ( getUserEventTracingEnabled
  )
where

import GHC.Internal.Base

#if !defined(javascript_HOST_ARCH)

import GHC.Internal.Ptr
import GHC.Internal.Foreign.C.Types
import GHC.Internal.Foreign.Marshal.Utils
import GHC.Internal.Foreign.Storable
import GHC.Internal.Data.Functor ((<$>))

#include "Rts.h"
#include "rts/Flags.h"

foreign import ccall "&RtsFlags" rtsFlagsPtr :: Ptr ()
#endif

-- | Specialized version of 'getTraceFlags' for just checking if user
-- event tracing is enabled.
getUserEventTracingEnabled :: IO Bool
getUserEventTracingEnabled = do
#if defined(javascript_HOST_ARCH)
  -- The JS backend does not currently have trace flags
  pure False
#else
  let ptr = (#ptr RTS_FLAGS, TraceFlags) rtsFlagsPtr
  toBool <$> (#{peek TRACE_FLAGS, user} ptr :: IO CBool)
#endif