Commit 6ef2fc2e authored by simonpj@microsoft.com's avatar simonpj@microsoft.com

Comment out deeply suspicious (and unused) function insertStableSymbol

The function insertStableSymbol looks utterly wrong, because it
coerces a value of type 'a' to an Addr#!  That was in turn making the
code generator get confused (now improved), but since insertStableSymbol
isn't used at all, I'm just commenting it out.

Meanwhile, this patch also enhances CoreToStg to report the most egregious
cases where an unsafe coerce is going to confuse the code generator.
parent 604121df
......@@ -17,7 +17,8 @@ module ObjLink (
loadObj, -- :: String -> IO ()
unloadObj, -- :: String -> IO ()
insertSymbol, -- :: String -> String -> Ptr a -> IO ()
insertStableSymbol, -- :: String -> String -> a -> IO ()
-- Suspicious; see defn
-- insertStableSymbol, -- :: String -> String -> a -> IO ()
lookupSymbol, -- :: String -> IO (Maybe (Ptr a))
resolveObjs -- :: IO SuccessFlag
) where
......@@ -43,12 +44,14 @@ insertSymbol obj_name key symbol
withCString str $ \c_str ->
c_insertSymbol c_obj_name c_str symbol
{- Deeply suspicious use of unsafeCoerce#; should use makeStablePtr#
insertStableSymbol :: String -> String -> a -> IO ()
insertStableSymbol obj_name key symbol
= let str = prefixUnderscore key
in withCString obj_name $ \c_obj_name ->
withCString str $ \c_str ->
c_insertStableSymbol c_obj_name c_str (Ptr (unsafeCoerce# symbol))
-}
lookupSymbol :: String -> IO (Maybe (Ptr a))
lookupSymbol str_in = do
......@@ -98,8 +101,9 @@ resolveObjs = do
foreign import ccall unsafe "addDLL" c_addDLL :: CString -> IO CString
foreign import ccall unsafe "initLinker" initObjLinker :: IO ()
foreign import ccall unsafe "insertSymbol" c_insertSymbol :: CString -> CString -> Ptr a -> IO ()
foreign import ccall unsafe "insertStableSymbol" c_insertStableSymbol
:: CString -> CString -> Ptr a -> IO ()
-- Suspicious: should take a stable pointer
-- foreign import ccall unsafe "insertStableSymbol" c_insertStableSymbol
-- :: CString -> CString -> Ptr a -> IO ()
foreign import ccall unsafe "lookupSymbol" c_lookupSymbol :: CString -> IO (Ptr a)
foreign import ccall unsafe "loadObj" c_loadObj :: CString -> IO Int
foreign import ccall unsafe "unloadObj" c_unloadObj :: CString -> IO Int
......
......@@ -548,6 +548,21 @@ coreToStgArgs (arg : args) -- Non-type argument
StgLit lit -> StgLitArg lit
_ -> pprPanic "coreToStgArgs" (ppr arg)
in
-- WARNING: what if we have an argument like (v `cast` co)
-- where 'co' changes the representation type?
-- (This really only happens if co is unsafe.)
-- Then all the getArgAmode stuff in CgBindery will set the
-- cg_rep of the CgIdInfo based on the type of v, rather
-- than the type of 'co'.
-- This matters particularly when the function is a primop
-- or foreign call.
-- Wanted: a better solution than this hacky warning
let
arg_ty = exprType arg
stg_arg_ty = stgArgType stg_arg
in
WARN( isUnLiftedType arg_ty /= isUnLiftedType stg_arg_ty,
ptext SLIT("Dangerous-looking argument. Probable cause: bad unsafeCoerce#") $$ ppr arg)
returnLne (stg_arg : stg_args, fvs)
......
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