X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=compiler%2Fiface%2FLoadIface.lhs;h=34026a6bf6e02267065fbc7a9cabc946533764eb;hb=e4828ab96fc2ba5250a6676e4c1653602f8846c7;hp=00e9e7a26f86b915ebf1a6dbb16701c86cabc941;hpb=7fa861d23122d4d6a3053c09b5c636bad0478ad3;p=ghc-hetmet.git diff --git a/compiler/iface/LoadIface.lhs b/compiler/iface/LoadIface.lhs index 00e9e7a..34026a6 100644 --- a/compiler/iface/LoadIface.lhs +++ b/compiler/iface/LoadIface.lhs @@ -6,6 +6,13 @@ Loading interface files \begin{code} +{-# OPTIONS -w #-} +-- The above warning supression flag is a temporary kludge. +-- While working on this module you are encouraged to remove it and fix +-- any warnings in the module. See +-- http://hackage.haskell.org/trac/ghc/wiki/Commentary/CodingStyle#Warnings +-- for details + module LoadIface ( loadInterface, loadInterfaceForName, loadWiredInHomeIface, loadSrcInterface, loadSysInterface, loadOrphanModules, @@ -19,7 +26,7 @@ module LoadIface ( #include "HsVersions.h" import {-# SOURCE #-} TcIface( tcIfaceDecl, tcIfaceRules, tcIfaceInst, - tcIfaceFamInst ) + tcIfaceFamInst, tcIfaceVectInfo ) import DynFlags import IfaceSyn @@ -38,7 +45,6 @@ import InstEnv import FamInstEnv import Name import NameEnv -import NameSet import MkId import Module import OccName @@ -52,7 +58,6 @@ import Outputable import BinIface import Panic -import Control.Monad (when) import Data.List import Data.Maybe import Data.IORef @@ -120,6 +125,7 @@ loadInterfaceForName doc name -- | An 'IfM' function to load the home interface for a wired-in thing, -- so that we're sure that we see its instance declarations and rules +-- See Note [Loading instances] loadWiredInHomeIface :: Name -> IfM lcl () loadWiredInHomeIface name = ASSERT( isWiredInName name ) @@ -136,6 +142,27 @@ loadSysInterface doc mod_name Succeeded iface -> return iface } \end{code} +Note [Loading instances] +~~~~~~~~~~~~~~~~~~~~~~~~ +We need to make sure that we have at least *read* the interface files +for any module with an instance decl or RULE that we might want. + +* If the instance decl is an orphan, we have a whole separate mechanism + (loadOprhanModules) + +* If the instance decl not an orphan, then the act of looking at the + TyCon or Class will force in the defining module for the + TyCon/Class, and hence the instance decl + +* BUT, if the TyCon is a wired-in TyCon, we don't really need its interface; + but we must make sure we read its interface in case it has instances or + rules. That is what LoadIface.loadWiredInHomeInterface does. It's called + from TcIface.{tcImportDecl, checkWiredInTyCon, ifCHeckWiredInThing} + +All of this is done by the type checker. The renamer plays no role. +(It used to, but no longer.) + + %********************************************************* %* * @@ -239,6 +266,8 @@ loadInterface doc_str mod from ; new_eps_insts <- mapM tcIfaceInst (mi_insts iface) ; new_eps_fam_insts <- mapM tcIfaceFamInst (mi_fam_insts iface) ; new_eps_rules <- tcIfaceRules ignore_prags (mi_rules iface) + ; new_eps_vect_info <- tcIfaceVectInfo mod (mkNameEnv new_eps_decls) + (mi_vect_info iface) ; let { final_iface = iface { mi_decls = panic "No mi_decls in PIT", @@ -246,11 +275,6 @@ loadInterface doc_str mod from mi_fam_insts = panic "No mi_fam_insts in PIT", mi_rules = panic "No mi_rules in PIT" } - ; new_eps_vect_info = - VectInfo { - vectInfoCCVar = mkNameSet - (ifaceVectInfoCCVar . mi_vect_info $ iface) - } } ; updateEps_ $ \ eps -> @@ -283,8 +307,8 @@ loadInterface doc_str mod from badDepMsg mod = hang (ptext SLIT("Interface file inconsistency:")) - 2 (sep [ptext SLIT("home-package module") <+> quotes (ppr mod) <+> ptext SLIT("is mentioned is needed,"), - ptext SLIT("but is not among the dependencies of interfaces directly imported by the module being compiled")]) + 2 (sep [ptext SLIT("home-package module") <+> quotes (ppr mod) <+> ptext SLIT("is needed,"), + ptext SLIT("but is not listed in the dependencies of the interfaces directly imported by the module being compiled")]) ----------------------------------------------------- -- Loading type/class/value decls @@ -319,9 +343,9 @@ loadDecl :: Bool -- Don't load pragmas into the decl pool loadDecl ignore_prags mod (_version, decl) = do { -- Populate the name cache with final versions of all -- the names associated with the decl - main_name <- mk_new_bndr mod (ifName decl) + main_name <- lookupOrig mod (ifName decl) -- ; traceIf (text "Loading decl for " <> ppr main_name) - ; implicit_names <- mapM (mk_new_bndr mod) (ifaceDeclSubBndrs decl) + ; implicit_names <- mapM (lookupOrig mod) (ifaceDeclSubBndrs decl) -- Typecheck the thing, lazily -- NB. Firstly, the laziness is there in case we never need the @@ -333,49 +357,73 @@ loadDecl ignore_prags mod (_version, decl) ; thing <- forkM doc $ do { bumpDeclStats main_name ; tcIfaceDecl ignore_prags decl } - -- Populate the type environment with the implicitTyThings too. - -- - -- Note [Tricky iface loop] - -- ~~~~~~~~~~~~~~~~~~~~~~~~ - -- The delicate point here is that 'mini-env' should be - -- buildable from 'thing' without demanding any of the things 'forkM'd - -- by tcIfaceDecl. For example - -- class C a where { data T a; op :: T a -> Int } - -- We return the bindings - -- [("C", ), ("T", lookup env "T"), ("op", lookup env "op")] - -- The call (lookup env "T") must return the tycon T without first demanding - -- op; because getting the latter will look up T, hence loop. - -- - -- Of course, there is no reason in principle why (lookup env "T") should demand - -- anything do to with op, but take care: - -- (a) implicitTyThings, and - -- (b) getOccName of all the things returned by implicitThings, - -- must not depend on any of the nested type-checks - -- - -- All a bit too finely-balanced for my liking. - + -- Populate the type environment with the implicitTyThings too. + -- + -- Note [Tricky iface loop] + -- ~~~~~~~~~~~~~~~~~~~~~~~~ + -- Summary: The delicate point here is that 'mini-env' must be + -- buildable from 'thing' without demanding any of the things + -- 'forkM'd by tcIfaceDecl. + -- + -- In more detail: Consider the example + -- data T a = MkT { x :: T a } + -- The implicitTyThings of T are: [ , ] + -- (plus their workers, wrappers, coercions etc etc) + -- + -- We want to return an environment + -- [ "MkT" -> , "x" -> , ... ] + -- (where the "MkT" is the *Name* associated with MkT, etc.) + -- + -- We do this by mapping the implict_names to the associated + -- TyThings. By the invariant on ifaceDeclSubBndrs and + -- implicitTyThings, we can use getOccName on the implicit + -- TyThings to make this association: each Name's OccName should + -- be the OccName of exactly one implictTyThing. So the key is + -- to define a "mini-env" + -- + -- [ 'MkT' -> , 'x' -> , ... ] + -- where the 'MkT' here is the *OccName* associated with MkT. + -- + -- However, there is a subtlety: due to how type checking needs + -- to be staged, we can't poke on the forkM'd thunks inside the + -- implictTyThings while building this mini-env. + -- If we poke these thunks too early, two problems could happen: + -- (1) When processing mutually recursive modules across + -- hs-boot boundaries, poking too early will do the + -- type-checking before the recursive knot has been tied, + -- so things will be type-checked in the wrong + -- environment, and necessary variables won't be in + -- scope. + -- + -- (2) Looking up one OccName in the mini_env will cause + -- others to be looked up, which might cause that + -- original one to be looked up again, and hence loop. + -- + -- The code below works because of the following invariant: + -- getOccName on a TyThing does not force the suspended type + -- checks in order to extract the name. For example, we don't + -- poke on the "T a" type of on the way to + -- extracting 's OccName. Of course, there is no + -- reason in principle why getting the OccName should force the + -- thunks, but this means we need to be careful in + -- implicitTyThings and its helper functions. + -- + -- All a bit too finely-balanced for my liking. + + -- This mini-env and lookup function mediates between the + -- *Name*s n and the map from *OccName*s to the implicit TyThings ; let mini_env = mkOccEnv [(getOccName t, t) | t <- implicitTyThings thing] lookup n = case lookupOccEnv mini_env (getOccName n) of Just thing -> thing Nothing -> pprPanic "loadDecl" (ppr main_name <+> ppr n $$ ppr (decl)) - ; returnM $ (main_name, thing) : [(n, lookup n) | n <- implicit_names] + ; returnM $ (main_name, thing) : + -- uses the invariant that implicit_names and + -- implictTyThings are bijective + [(n, lookup n) | n <- implicit_names] } - -- We build a list from the *known* names, with (lookup n) thunks - -- as the TyThings. That way we can extend the PTE without poking the - -- thunks where - -- mk_new_bndr allocates in the name cache the final canonical - -- name for the thing, with the correct - -- * parent - -- * location - -- imported name, to fix the module correctly in the cache - mk_new_bndr mod occ - = newGlobalBinder mod occ - (importedSrcLoc (showSDoc (ppr (moduleName mod)))) - -- ToDo: qualify with the package name if necessary - doc = ptext SLIT("Declaration for") <+> ppr (ifName decl) bumpDeclStats :: Name -> IfL () -- Record that one more declaration has actually been used @@ -577,6 +625,7 @@ pprModIface iface <+> ppr (mi_mod_vers iface) <+> pp_sub_vers <+> (if mi_orphan iface then ptext SLIT("[orphan module]") else empty) <+> (if mi_finsts iface then ptext SLIT("[family instance module]") else empty) + <+> (if mi_hpc iface then ptext SLIT("[hpc]") else empty) <+> integer opt_HiVersion <+> ptext SLIT("where") , vcat (map pprExport (mi_exports iface)) @@ -587,8 +636,9 @@ pprModIface iface , vcat (map ppr (mi_insts iface)) , vcat (map ppr (mi_fam_insts iface)) , vcat (map ppr (mi_rules iface)) + , pprVectInfo (mi_vect_info iface) , pprDeprecs (mi_deprecs iface) - ] + ] where pp_boot | mi_boot iface = ptext SLIT("[boot]") | otherwise = empty @@ -659,6 +709,17 @@ pprFixities fixes = ptext SLIT("fixities") <+> pprWithCommas pprFix fixes where pprFix (occ,fix) = ppr fix <+> ppr occ +pprVectInfo :: IfaceVectInfo -> SDoc +pprVectInfo (IfaceVectInfo { ifaceVectInfoVar = vars + , ifaceVectInfoTyCon = tycons + , ifaceVectInfoTyConReuse = tyconsReuse + }) = + vcat + [ ptext SLIT("vectorised variables:") <+> hsep (map ppr vars) + , ptext SLIT("vectorised tycons:") <+> hsep (map ppr tycons) + , ptext SLIT("vectorised reused tycons:") <+> hsep (map ppr tyconsReuse) + ] + pprDeprecs NoDeprecs = empty pprDeprecs (DeprecAll txt) = ptext SLIT("Deprecate all") <+> doubleQuotes (ftext txt) pprDeprecs (DeprecSome prs) = ptext SLIT("Deprecate") <+> vcat (map pprDeprec prs)