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
| 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}
|
|
|
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