%
-% (c) The GRASP Project, Glasgow University, 1992-1998
+% (c) The GRASP Project, Glasgow University, 1992-2000
%
\section{Panic error messages}
some unnecessary loops in the module dependency graph.
\begin{code}
-module Panic ( panic, panic#, assertPanic, trace ) where
+module Panic
+ (
+ GhcException(..), ghcError, progName,
+ pgmError,
+ panic, panic#, assertPanic, trace,
+ showException, showGhcException, tryMost,
+ installSignalHandlers,
-import GlaExts( trace )
+ catchJust, tryJust, ioErrors, throwTo,
+ ) where
#include "HsVersions.h"
+
+import Config
+import FastTypes
+
+#ifndef mingw32_HOST_OS
+# if __GLASGOW_HASKELL__ > 504
+import System.Posix.Signals
+# else
+import Posix ( Handler(Catch), installHandler, sigINT, sigQUIT )
+# endif /* GHC > 504 */
+#endif /* mingw32_HOST_OS */
+
+#if defined(mingw32_HOST_OS) && __GLASGOW_HASKELL__ >= 603
+import GHC.ConsoleHandler
+#endif
+
+# if __GLASGOW_HASKELL__ < 500
+import EXCEPTION ( raiseInThread )
+# else
+import EXCEPTION ( throwTo )
+# endif /* GHC < 500 */
+
+#if __GLASGOW_HASKELL__ > 408
+import EXCEPTION ( catchJust, tryJust, ioErrors )
+#endif
+
+import CONCURRENT ( myThreadId )
+import DYNAMIC
+import qualified EXCEPTION as Exception
+import TRACE ( trace )
+import UNSAFE_IO ( unsafePerformIO )
+
+import System
\end{code}
+GHC's own exception type.
+
\begin{code}
-panic :: String -> a
-panic x = error ("panic! (the `impossible' happened):\n\t"
- ++ x ++ "\n\n"
- ++ "Please report it as a compiler bug "
- ++ "to glasgow-haskell-bugs@dcs.gla.ac.uk.\n\n" )
+ghcError :: GhcException -> a
+ghcError e = Exception.throwDyn e
+
+-- error messages all take the form
+--
+-- <location>: <error>
+--
+-- If the location is on the command line, or in GHC itself, then
+-- <location>="ghc". All of the error types below correspond to
+-- a <location> of "ghc", except for ProgramError (where the string is
+-- assumed to contain a location already, so we don't print one).
+
+data GhcException
+ = PhaseFailed String -- name of phase
+ ExitCode -- an external phase (eg. cpp) failed
+ | Interrupted -- someone pressed ^C
+ | UsageError String -- prints the short usage msg after the error
+ | CmdLineError String -- cmdline prob, but doesn't print usage
+ | Panic String -- the `impossible' happened
+ | InstallationError String -- an installation problem
+ | ProgramError String -- error in the user's code, probably
+ deriving Eq
+
+progName = unsafePerformIO (getProgName)
+{-# NOINLINE progName #-}
+
+short_usage = "Usage: For basic information, try the `--help' option."
+
+showException :: Exception.Exception -> String
+-- Show expected dynamic exceptions specially
+showException (Exception.DynException d) | Just e <- fromDynamic d
+ = show (e::GhcException)
+showException other_exn = show other_exn
+
+instance Show GhcException where
+ showsPrec _ e@(ProgramError _) = showGhcException e
+ showsPrec _ e = showString progName . showString ": " . showGhcException e
+
+showGhcException (UsageError str)
+ = showString str . showChar '\n' . showString short_usage
+showGhcException (PhaseFailed phase code)
+ = showString "phase `" . showString phase .
+ showString "' failed (exitcode = " . shows int_code .
+ showString ")"
+ where
+ int_code =
+ case code of
+ ExitSuccess -> (0::Int)
+ ExitFailure x -> x
+showGhcException (CmdLineError str)
+ = showString str
+showGhcException (ProgramError str)
+ = showString str
+showGhcException (InstallationError str)
+ = showString str
+showGhcException (Interrupted)
+ = showString "interrupted"
+showGhcException (Panic s)
+ = showString ("panic! (the `impossible' happened, GHC version "
+ ++ cProjectVersion ++ "):\n\t"
+ ++ s ++ "\n\n"
+ ++ "Please report it as a compiler bug "
+ ++ "to glasgow-haskell-bugs@haskell.org,\n"
+ ++ "or http://sourceforge.net/projects/ghc/.\n\n")
+
+#if __GLASGOW_HASKELL__ < 603
+myMkTyConApp = mkAppTy
+#else
+myMkTyConApp = mkTyConApp
+#endif
+
+ghcExceptionTc = mkTyCon "GhcException"
+{-# NOINLINE ghcExceptionTc #-}
+instance Typeable GhcException where
+ typeOf _ = myMkTyConApp ghcExceptionTc []
+\end{code}
+
+Panics and asserts.
+
+\begin{code}
+panic, pgmError :: String -> a
+panic x = Exception.throwDyn (Panic x)
+pgmError x = Exception.throwDyn (ProgramError x)
-- #-versions because panic can't return an unboxed int, and that's
-- what TAG_ is with GHC at the moment. Ugh. (Simon)
-- No, man -- Too Beautiful! (Will)
-panic# :: String -> FAST_INT
-panic# s = case (panic s) of () -> ILIT(0)
+panic# :: String -> FastInt
+panic# s = case (panic s) of () -> _ILIT 0
assertPanic :: String -> Int -> a
-assertPanic file line = panic ("ASSERT failed! file " ++ file ++ ", line " ++ show line)
+assertPanic file line =
+ Exception.throw (Exception.AssertionFailed
+ ("ASSERT failed! file " ++ file ++ ", line " ++ show line))
+\end{code}
+
+\begin{code}
+-- | tryMost is like try, but passes through Interrupted and Panic
+-- exceptions. Used when we want soft failures when reading interface
+-- files, for example.
+
+tryMost :: IO a -> IO (Either Exception.Exception a)
+tryMost action = do r <- myTry action; filter r
+ where
+ filter (Left e@(Exception.DynException d))
+ | Just ghc_ex <- fromDynamic d
+ = case ghc_ex of
+ Interrupted -> Exception.throw e
+ Panic _ -> Exception.throw e
+ _other -> return (Left e)
+ filter other
+ = return other
+
+#if __GLASGOW_HASKELL__ <= 408
+myTry = Exception.tryAllIO
+#else
+myTry = Exception.try
+#endif
+\end{code}
+
+Compatibility stuff:
+
+\begin{code}
+#if __GLASGOW_HASKELL__ <= 408
+catchJust = Exception.catchIO
+tryJust = Exception.tryIO
+ioErrors = Exception.justIoErrors
+throwTo = Exception.raiseInThread
+#endif
+\end{code}
+
+Standard signal handlers for catching ^C, which just throw an
+exception in the main thread. NOTE: must be called from the main
+thread.
+
+\begin{code}
+installSignalHandlers :: IO ()
+installSignalHandlers = do
+ main_thread <- myThreadId
+ let
+ interrupt_exn = Exception.DynException (toDyn Interrupted)
+ interrupt = throwTo main_thread interrupt_exn
+ --
+#if !defined(mingw32_HOST_OS)
+ installHandler sigQUIT (Catch interrupt) Nothing
+ installHandler sigINT (Catch interrupt) Nothing
+ return ()
+#elif __GLASGOW_HASKELL__ >= 603
+ -- GHC 6.3+ has support for console events on Windows
+ -- NOTE: running GHCi under a bash shell for some reason requires
+ -- you to press Ctrl-Break rather than Ctrl-C to provoke
+ -- an interrupt. Ctrl-C is getting blocked somewhere, I don't know
+ -- why --SDM 17/12/2004
+ let sig_handler ControlC = interrupt
+ sig_handler Break = interrupt
+ sig_handler _ = return ()
+
+ installHandler (Catch sig_handler)
+ return ()
+#else
+ return () -- nothing
+#endif
\end{code}
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