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|
{-# LANGUAGE Trustworthy #-}
-----------------------------------------------------------------------------
-- |
-- Module : GHC.Stack
-- Copyright : (c) The University of Glasgow 2011
-- License : see libraries/base/LICENSE
--
-- Maintainer : cvs-ghc@haskell.org
-- Stability : internal
-- Portability : non-portable (GHC Extensions)
--
-- Access to GHC's call-stack simulation
--
-- @since 4.5.0.0
-----------------------------------------------------------------------------
{-# LANGUAGE MagicHash, NoImplicitPrelude, ImplicitParams, RankNTypes #-}
module GHC.Stack (
errorWithStackTrace,
-- * Profiling call stacks
currentCallStack,
whoCreated,
-- * HasCallStack call stacks
CallStack, HasCallStack, callStack, emptyCallStack, freezeCallStack,
fromCallSiteList, getCallStack, popCallStack, prettyCallStack,
pushCallStack, withFrozenCallStack,
-- * Source locations
SrcLoc(..), prettySrcLoc,
-- * Internals
CostCentreStack,
CostCentre,
getCurrentCCS,
getCCSOf,
clearCCS,
ccsCC,
ccsParent,
ccLabel,
ccModule,
ccSrcSpan,
ccsToStrings,
renderStack
) where
import GHC.Stack.CCS
import GHC.Stack.Types
import GHC.IO
import GHC.Base
import GHC.List
import GHC.Exception
-- | Like the function 'error', but appends a stack trace to the error
-- message if one is available.
--
-- @since 4.7.0.0
{-# DEPRECATED errorWithStackTrace "'error' appends the call stack now" #-}
-- DEPRECATED in 8.0.1
errorWithStackTrace :: String -> a
errorWithStackTrace x = unsafeDupablePerformIO $ do
stack <- ccsToStrings =<< getCurrentCCS x
if null stack
then throwIO (ErrorCall x)
else throwIO (ErrorCallWithLocation x (renderStack stack))
-- | Pop the most recent call-site off the 'CallStack'.
--
-- This function, like 'pushCallStack', has no effect on a frozen 'CallStack'.
--
-- @since 4.9.0.0
popCallStack :: CallStack -> CallStack
popCallStack stk = case stk of
EmptyCallStack -> errorWithoutStackTrace "popCallStack: empty stack"
PushCallStack _ _ stk' -> stk'
FreezeCallStack _ -> stk
{-# INLINE popCallStack #-}
-- | Return the current 'CallStack'.
--
-- Does *not* include the call-site of 'callStack'.
--
-- @since 4.9.0.0
callStack :: HasCallStack => CallStack
callStack =
case ?callStack of
EmptyCallStack -> EmptyCallStack
_ -> popCallStack ?callStack
{-# INLINE callStack #-}
-- | Perform some computation without adding new entries to the 'CallStack'.
--
-- @since 4.9.0.0
withFrozenCallStack :: HasCallStack
=> ( HasCallStack => a )
-> a
withFrozenCallStack do_this =
-- we pop the stack before freezing it to remove
-- withFrozenCallStack's call-site
let ?callStack = freezeCallStack (popCallStack callStack)
in do_this
|
