Do you put the FS table back after running the plugin? If not, the same unique may be allocated more than once. S | -----Original Message----- | From: ghc-commits-bounces@haskell.org [mailto:ghc-commits- | bounces@haskell.org] On Behalf Of Nicolas Frisby | Sent: 04 July 2013 05:13 | To: ghc-commits@haskell.org | Subject: [commit: ghc] master: include FastString.string_table in | CoreMonad.reinitializeGlobals (163de25) | | Repository : http://darcs.haskell.org/ghc.git/ | | On branch : master | | https://github.com/ghc/ghc/commit/163de25813d12764aa5ded1666af7c06fee0d6 | 7e | | >--------------------------------------------------------------- | | commit 163de25813d12764aa5ded1666af7c06fee0d67e | Author: Nicolas Frisby <nicolas.frisby@gmail.com> | Date: Wed Jul 3 18:23:54 2013 -0500 | | include FastString.string_table in CoreMonad.reinitializeGlobals | | >--------------------------------------------------------------- | | compiler/simplCore/CoreMonad.lhs | 36 +++++++++++++++++++++++++++++++-- | --- | compiler/utils/FastString.lhs | 15 ++++++++++++++- | 2 files changed, 45 insertions(+), 6 deletions(-) | | diff --git a/compiler/simplCore/CoreMonad.lhs | b/compiler/simplCore/CoreMonad.lhs | index e11c139..7fe5554 100644 | --- a/compiler/simplCore/CoreMonad.lhs | +++ b/compiler/simplCore/CoreMonad.lhs | @@ -722,11 +722,12 @@ data CoreReader = CoreReader { | cr_hsc_env :: HscEnv, | cr_rule_base :: RuleBase, | cr_module :: Module, | - cr_globals :: ((Bool, [String]), | + cr_globals :: (,,) (Bool, [String]) -- from StaticFlags | + FastStringTable -- from FastString | #ifdef GHCI | - (MVar PersistentLinkerState, Bool)) | + (MVar PersistentLinkerState, Bool) -- | from Linker | #else | - ()) | + () | #endif | } | | @@ -789,7 +790,7 @@ runCoreM :: HscEnv | -> CoreM a | -> IO (a, SimplCount) | runCoreM hsc_env rule_base us mod m = do | - glbls <- liftM2 (,) saveStaticFlagGlobals saveLinkerGlobals | + glbls <- liftM3 (,,) saveStaticFlagGlobals saveFSTable | saveLinkerGlobals | liftM extract $ runIOEnv (reader glbls) $ unCoreM m state | where | reader glbls = CoreReader { | @@ -891,6 +892,8 @@ getOrigNameCache = do | %* * | | %*********************************************************************** | * | | +Note [Initializing globals] | + | This is a rather annoying function. When a plugin is loaded, it | currently | gets linked against a *newly loaded* copy of the GHC package. This | would | not be a problem, except that the new copy has its own mutable state | @@ -921,13 +924,36 @@ I've threaded the cr_globals through CoreM rather | than giving them as an | argument to the plugin function so that we can turn this function into | (return ()) without breaking any plugins when we eventually get 1. | working. | | +----- | + | +We include the FastString table in this mechanism, because we'd like | +FastStrings created by the plugin to have the same uniques as similar | strings | +created by the host compiler itself. For example, this allows plugins | to | +lookup known names (eg `mkTcOcc "MySpecialType"`) in the GlobalRdrEnv | or even | +re-invoke the parser. | + | +In particular, the following little sanity test was failing in a plugin | +prototyping safe newtype-coercions. | + | + let rdrName = mkModuleName "GHC.NT.Type" `mkRdrQual` mkTcOcc "NT" | + putMsgS $ showSDoc dflags $ ppr $ lookupGRE_RdrName rdrName $ | mg_rdr_env guts | + | +`mkTcOcc` involves the lookup (or creation) of a FastString. Since the | +plugin's FastString.string_table is empty, constructing the RdrName | also | +allocates new uniques for the FastStrings "GHC.NT.Type" and "NT". | These | +uniques are almost certainly unequal to the ones that the host compiler | +originally assigned to those FastStrings. Thus the lookup fails since | the | +domain of the GlobalRdrEnv is affected by the RdrName's OccName's | FastString's | +unique. | + | \begin{code} | reinitializeGlobals :: CoreM () | reinitializeGlobals = do | - (sf_globals, linker_globals) <- read cr_globals | + (sf_globals, fs_table, linker_globals) <- read cr_globals | hsc_env <- getHscEnv | let dflags = hsc_dflags hsc_env | liftIO $ restoreStaticFlagGlobals sf_globals | + liftIO $ restoreFSTable fs_table | liftIO $ restoreLinkerGlobals linker_globals | liftIO $ setUnsafeGlobalDynFlags dflags | \end{code} | diff --git a/compiler/utils/FastString.lhs | b/compiler/utils/FastString.lhs | index 36b1b1e..0bdf0a0 100644 | --- a/compiler/utils/FastString.lhs | +++ b/compiler/utils/FastString.lhs | @@ -91,7 +91,10 @@ module FastString | unpackLitString, | | -- ** Operations | - lengthLS | + lengthLS, | + | + -- * Saving/restoring globals | + saveFSTable, restoreFSTable, FastStringTable | ) where | | #include "HsVersions.h" | @@ -573,4 +576,14 @@ fsLit x = mkFastString x | forall x . sLit (unpackCString# x) = mkLitString# x #-} | {-# RULES "fslit" | forall x . fsLit (unpackCString# x) = mkFastString# x #-} | + | + | +-------------------- | +-- for plugins; see Note [Initializing globals] in CoreMonad | + | +saveFSTable :: IO FastStringTable | +saveFSTable = readIORef string_table | + | +restoreFSTable :: FastStringTable -> IO () | +restoreFSTable = writeIORef string_table | \end{code} | | | | _______________________________________________ | ghc-commits mailing list | ghc-commits@haskell.org | http://www.haskell.org/mailman/listinfo/ghc-commits