{-# OPTIONS_GHC -optc-DPROFILING #-}
{-# LINE 1 "libraries/base/GHC/Stack/CCS.hsc" #-}
{-# LANGUAGE Trustworthy #-}

-----------------------------------------------------------------------------
-- |
-- Module      :  GHC.Stack.CCS
-- 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 UnboxedTuples, MagicHash, NoImplicitPrelude #-}
module GHC.Stack.CCS (
    -- * Call stacks
    currentCallStack,
    whoCreated,

    -- * Internals
    CostCentreStack,
    CostCentre,
    getCurrentCCS,
    getCCSOf,
    clearCCS,
    ccsCC,
    ccsParent,
    ccLabel,
    ccModule,
    ccSrcSpan,
    ccsToStrings,
    renderStack,
  ) where

import Foreign
import Foreign.C

import GHC.Base
import GHC.Ptr
import GHC.Foreign as GHC
import GHC.IO.Encoding
import GHC.List ( concatMap, reverse )




-- | A cost-centre stack from GHC's cost-center profiler.
data CostCentreStack

-- | A cost-centre from GHC's cost-center profiler.
data CostCentre

-- | Returns the current 'CostCentreStack' (value is @nullPtr@ if the current
-- program was not compiled with profiling support). Takes a dummy argument
-- which can be used to avoid the call to @getCurrentCCS@ being floated out by
-- the simplifier, which would result in an uninformative stack ("CAF").
getCurrentCCS :: dummy -> IO (Ptr CostCentreStack)
getCurrentCCS :: forall dummy. dummy -> IO (Ptr CostCentreStack)
getCurrentCCS dummy
dummy = (State# RealWorld -> (# State# RealWorld, Ptr CostCentreStack #))
-> IO (Ptr CostCentreStack)
forall a. (State# RealWorld -> (# State# RealWorld, a #)) -> IO a
IO ((State# RealWorld -> (# State# RealWorld, Ptr CostCentreStack #))
 -> IO (Ptr CostCentreStack))
-> (State# RealWorld
    -> (# State# RealWorld, Ptr CostCentreStack #))
-> IO (Ptr CostCentreStack)
forall a b. (a -> b) -> a -> b
$ \State# RealWorld
s ->
   case dummy -> State# RealWorld -> (# State# RealWorld, Addr# #)
forall a d. a -> State# d -> (# State# d, Addr# #)
getCurrentCCS# dummy
dummy State# RealWorld
s of
     (# State# RealWorld
s', Addr#
addr #) -> (# State# RealWorld
s', Addr# -> Ptr CostCentreStack
forall a. Addr# -> Ptr a
Ptr Addr#
addr #)

-- | Get the 'CostCentreStack' associated with the given value.
getCCSOf :: a -> IO (Ptr CostCentreStack)
getCCSOf :: forall dummy. dummy -> IO (Ptr CostCentreStack)
getCCSOf a
obj = (State# RealWorld -> (# State# RealWorld, Ptr CostCentreStack #))
-> IO (Ptr CostCentreStack)
forall a. (State# RealWorld -> (# State# RealWorld, a #)) -> IO a
IO ((State# RealWorld -> (# State# RealWorld, Ptr CostCentreStack #))
 -> IO (Ptr CostCentreStack))
-> (State# RealWorld
    -> (# State# RealWorld, Ptr CostCentreStack #))
-> IO (Ptr CostCentreStack)
forall a b. (a -> b) -> a -> b
$ \State# RealWorld
s ->
   case a -> State# RealWorld -> (# State# RealWorld, Addr# #)
forall a d. a -> State# d -> (# State# d, Addr# #)
getCCSOf# a
obj State# RealWorld
s of
     (# State# RealWorld
s', Addr#
addr #) -> (# State# RealWorld
s', Addr# -> Ptr CostCentreStack
forall a. Addr# -> Ptr a
Ptr Addr#
addr #)

-- | Run a computation with an empty cost-center stack. For example, this is
-- used by the interpreter to run an interpreted computation without the call
-- stack showing that it was invoked from GHC.
clearCCS :: IO a -> IO a
clearCCS :: forall a. IO a -> IO a
clearCCS (IO State# RealWorld -> (# State# RealWorld, a #)
m) = (State# RealWorld -> (# State# RealWorld, a #)) -> IO a
forall a. (State# RealWorld -> (# State# RealWorld, a #)) -> IO a
IO ((State# RealWorld -> (# State# RealWorld, a #)) -> IO a)
-> (State# RealWorld -> (# State# RealWorld, a #)) -> IO a
forall a b. (a -> b) -> a -> b
$ \State# RealWorld
s -> (State# RealWorld -> (# State# RealWorld, a #))
-> State# RealWorld -> (# State# RealWorld, a #)
forall d a.
(State# d -> (# State# d, a #)) -> State# d -> (# State# d, a #)
clearCCS# State# RealWorld -> (# State# RealWorld, a #)
m State# RealWorld
s

-- | Get the 'CostCentre' at the head of a 'CostCentreStack'.

{-# LINE 95 "libraries/base/GHC/Stack/CCS.hsc" #-}
ccsCC :: Ptr CostCentreStack -> IO (Ptr CostCentre)
ccsCC :: Ptr CostCentreStack -> IO (Ptr CostCentre)
ccsCC Ptr CostCentreStack
p = ((\Ptr CostCentreStack
hsc_ptr -> Ptr CostCentreStack -> Int -> IO (Ptr CostCentre)
forall b. Ptr b -> Int -> IO (Ptr CostCentre)
forall a b. Storable a => Ptr b -> Int -> IO a
peekByteOff Ptr CostCentreStack
hsc_ptr Int
8)) Ptr CostCentreStack
p
{-# LINE 97 "libraries/base/GHC/Stack/CCS.hsc" #-}

-- | Get the tail of a 'CostCentreStack'.
ccsParent :: Ptr CostCentreStack -> IO (Ptr CostCentreStack)
ccsParent :: Ptr CostCentreStack -> IO (Ptr CostCentreStack)
ccsParent Ptr CostCentreStack
p = ((\Ptr CostCentreStack
hsc_ptr -> Ptr CostCentreStack -> Int -> IO (Ptr CostCentreStack)
forall b. Ptr b -> Int -> IO (Ptr CostCentreStack)
forall a b. Storable a => Ptr b -> Int -> IO a
peekByteOff Ptr CostCentreStack
hsc_ptr Int
16)) Ptr CostCentreStack
p
{-# LINE 101 "libraries/base/GHC/Stack/CCS.hsc" #-}

-- | Get the label of a 'CostCentre'.
ccLabel :: Ptr CostCentre -> IO CString
ccLabel :: Ptr CostCentre -> IO CString
ccLabel Ptr CostCentre
p = ((\Ptr CostCentre
hsc_ptr -> Ptr CostCentre -> Int -> IO CString
forall b. Ptr b -> Int -> IO CString
forall a b. Storable a => Ptr b -> Int -> IO a
peekByteOff Ptr CostCentre
hsc_ptr Int
8)) Ptr CostCentre
p
{-# LINE 105 "libraries/base/GHC/Stack/CCS.hsc" #-}

-- | Get the module of a 'CostCentre'.
ccModule :: Ptr CostCentre -> IO CString
ccModule :: Ptr CostCentre -> IO CString
ccModule Ptr CostCentre
p = ((\Ptr CostCentre
hsc_ptr -> Ptr CostCentre -> Int -> IO CString
forall b. Ptr b -> Int -> IO CString
forall a b. Storable a => Ptr b -> Int -> IO a
peekByteOff Ptr CostCentre
hsc_ptr Int
16)) Ptr CostCentre
p
{-# LINE 109 "libraries/base/GHC/Stack/CCS.hsc" #-}

-- | Get the source span of a 'CostCentre'.
ccSrcSpan :: Ptr CostCentre -> IO CString
ccSrcSpan :: Ptr CostCentre -> IO CString
ccSrcSpan Ptr CostCentre
p = ((\Ptr CostCentre
hsc_ptr -> Ptr CostCentre -> Int -> IO CString
forall b. Ptr b -> Int -> IO CString
forall a b. Storable a => Ptr b -> Int -> IO a
peekByteOff Ptr CostCentre
hsc_ptr Int
24)) Ptr CostCentre
p
{-# LINE 113 "libraries/base/GHC/Stack/CCS.hsc" #-}

{-# LINE 114 "libraries/base/GHC/Stack/CCS.hsc" #-}

-- | Returns a @[String]@ representing the current call stack.  This
-- can be useful for debugging.
--
-- The implementation uses the call-stack simulation maintained by the
-- profiler, so it only works if the program was compiled with @-prof@
-- and contains suitable SCC annotations (e.g. by using @-fprof-auto@).
-- Otherwise, the list returned is likely to be empty or
-- uninformative.
--
-- @since 4.5.0.0
currentCallStack :: IO [String]
currentCallStack :: IO [String]
currentCallStack = Ptr CostCentreStack -> IO [String]
ccsToStrings (Ptr CostCentreStack -> IO [String])
-> IO (Ptr CostCentreStack) -> IO [String]
forall (m :: * -> *) a b. Monad m => (a -> m b) -> m a -> m b
=<< () -> IO (Ptr CostCentreStack)
forall dummy. dummy -> IO (Ptr CostCentreStack)
getCurrentCCS ()

-- | Format a 'CostCentreStack' as a list of lines.
ccsToStrings :: Ptr CostCentreStack -> IO [String]
ccsToStrings :: Ptr CostCentreStack -> IO [String]
ccsToStrings Ptr CostCentreStack
ccs0 = Ptr CostCentreStack -> [String] -> IO [String]
go Ptr CostCentreStack
ccs0 []
  where
    go :: Ptr CostCentreStack -> [String] -> IO [String]
go Ptr CostCentreStack
ccs [String]
acc
     | Ptr CostCentreStack
ccs Ptr CostCentreStack -> Ptr CostCentreStack -> Bool
forall a. Eq a => a -> a -> Bool
== Ptr CostCentreStack
forall a. Ptr a
nullPtr = [String] -> IO [String]
forall a. a -> IO a
forall (m :: * -> *) a. Monad m => a -> m a
return [String]
acc
     | Bool
otherwise = do
        Ptr CostCentre
cc  <- Ptr CostCentreStack -> IO (Ptr CostCentre)
ccsCC Ptr CostCentreStack
ccs
        String
lbl <- TextEncoding -> CString -> IO String
GHC.peekCString TextEncoding
utf8 (CString -> IO String) -> IO CString -> IO String
forall (m :: * -> *) a b. Monad m => (a -> m b) -> m a -> m b
=<< Ptr CostCentre -> IO CString
ccLabel Ptr CostCentre
cc
        String
mdl <- TextEncoding -> CString -> IO String
GHC.peekCString TextEncoding
utf8 (CString -> IO String) -> IO CString -> IO String
forall (m :: * -> *) a b. Monad m => (a -> m b) -> m a -> m b
=<< Ptr CostCentre -> IO CString
ccModule Ptr CostCentre
cc
        String
loc <- TextEncoding -> CString -> IO String
GHC.peekCString TextEncoding
utf8 (CString -> IO String) -> IO CString -> IO String
forall (m :: * -> *) a b. Monad m => (a -> m b) -> m a -> m b
=<< Ptr CostCentre -> IO CString
ccSrcSpan Ptr CostCentre
cc
        Ptr CostCentreStack
parent <- Ptr CostCentreStack -> IO (Ptr CostCentreStack)
ccsParent Ptr CostCentreStack
ccs
        if (String
mdl String -> String -> Bool
forall a. Eq a => a -> a -> Bool
== String
"MAIN" Bool -> Bool -> Bool
&& String
lbl String -> String -> Bool
forall a. Eq a => a -> a -> Bool
== String
"MAIN")
           then [String] -> IO [String]
forall a. a -> IO a
forall (m :: * -> *) a. Monad m => a -> m a
return [String]
acc
           else Ptr CostCentreStack -> [String] -> IO [String]
go Ptr CostCentreStack
parent ((String
mdl String -> String -> String
forall a. [a] -> [a] -> [a]
++ Char
'.'Char -> String -> String
forall a. a -> [a] -> [a]
:String
lbl String -> String -> String
forall a. [a] -> [a] -> [a]
++ Char
' 'Char -> String -> String
forall a. a -> [a] -> [a]
:Char
'('Char -> String -> String
forall a. a -> [a] -> [a]
:String
loc String -> String -> String
forall a. [a] -> [a] -> [a]
++ String
")") String -> [String] -> [String]
forall a. a -> [a] -> [a]
: [String]
acc)

-- | Get the stack trace attached to an object.
--
-- @since 4.5.0.0
whoCreated :: a -> IO [String]
whoCreated :: forall a. a -> IO [String]
whoCreated a
obj = do
  Ptr CostCentreStack
ccs <- a -> IO (Ptr CostCentreStack)
forall dummy. dummy -> IO (Ptr CostCentreStack)
getCCSOf a
obj
  Ptr CostCentreStack -> IO [String]
ccsToStrings Ptr CostCentreStack
ccs

renderStack :: [String] -> String
renderStack :: [String] -> String
renderStack [String]
strs =
  String
"CallStack (from -prof):" String -> String -> String
forall a. [a] -> [a] -> [a]
++ (String -> String) -> [String] -> String
forall a b. (a -> [b]) -> [a] -> [b]
concatMap (String
"\n  "String -> String -> String
forall a. [a] -> [a] -> [a]
++) ([String] -> [String]
forall a. [a] -> [a]
reverse [String]
strs)