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.

1 files changed, 7 insertions, 3 deletions

diff --git a/compiler/ghci/ObjLink.lhs b/compiler/ghci/ObjLink.lhs
index d5e0f7bd92..48deb46783 100644
--- a/compiler/ghci/ObjLink.lhs
+++ b/compiler/ghci/ObjLink.lhs
@@ -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