(c) The University of Glasgow 2002-2006

\begin{code}
module IfaceEnv (
	newGlobalBinder, newIPName, newImplicitBinder, 
	lookupIfaceTop,
	lookupOrig, lookupOrigNameCache, extendNameCache,
	newIfaceName, newIfaceNames,
	extendIfaceIdEnv, extendIfaceTyVarEnv, 
	tcIfaceLclId,     tcIfaceTyVar, 
	tcIfaceTick,

	ifaceExportNames,

	-- Name-cache stuff
	allocateGlobalBinder, initNameCache, 
        getNameCache, setNameCache
   ) where

#include "HsVersions.h"

import TcRnMonad
import TysWiredIn
import HscTypes
import TyCon
import DataCon
import Var
import Name
import OccName
import PrelNames
import Module
import UniqFM
import FastString
import UniqSupply
import FiniteMap
import BasicTypes
import SrcLoc
import MkId

import Outputable
\end{code}


%*********************************************************
%*							*
	Allocating new Names in the Name Cache
%*							*
%*********************************************************

\begin{code}
newGlobalBinder :: Module -> OccName -> SrcSpan -> TcRnIf a b Name
-- Used for source code and interface files, to make the
-- Name for a thing, given its Module and OccName
--
-- The cache may already already have a binding for this thing,
-- because we may have seen an occurrence before, but now is the
-- moment when we know its Module and SrcLoc in their full glory

newGlobalBinder mod occ loc
  = do	{ mod `seq` occ `seq` return ()	-- See notes with lookupOrig_help
--	; traceIf (text "newGlobalBinder" <+> ppr mod <+> ppr occ <+> ppr loc)
    	; name_supply <- getNameCache
	; let (name_supply', name) = allocateGlobalBinder 
					name_supply mod occ
					loc
	; setNameCache name_supply'
	; return name }

allocateGlobalBinder
  :: NameCache 
  -> Module -> OccName -> SrcSpan
  -> (NameCache, Name)
allocateGlobalBinder name_supply mod occ loc
  = case lookupOrigNameCache (nsNames name_supply) mod occ of
	-- A hit in the cache!  We are at the binding site of the name.
	-- This is the moment when we know the SrcLoc
	-- of the Name, so we set this field in the Name we return.
	--
	-- Then (bogus) multiple bindings of the same Name
	-- get different SrcLocs can can be reported as such.
	--
	-- Possible other reason: it might be in the cache because we
	-- 	encountered an occurrence before the binding site for an
	--	implicitly-imported Name.  Perhaps the current SrcLoc is
	--	better... but not really: it'll still just say 'imported'
	--
	-- IMPORTANT: Don't mess with wired-in names.  
	-- 	      Their wired-in-ness is in their NameSort
	--	      and their Module is correct.

	Just name | isWiredInName name -> (name_supply, name)
		  | otherwise -> (new_name_supply, name')
		  where
		    uniq      = nameUnique name
		    name'     = mkExternalName uniq mod occ loc
		    new_cache = extendNameCache (nsNames name_supply) mod occ name'
		    new_name_supply = name_supply {nsNames = new_cache}		     

	-- Miss in the cache!
	-- Build a completely new Name, and put it in the cache
	Nothing -> (new_name_supply, name)
		where
		  (us', us1)      = splitUniqSupply (nsUniqs name_supply)
		  uniq   	  = uniqFromSupply us1
		  name            = mkExternalName uniq mod occ loc
		  new_cache       = extendNameCache (nsNames name_supply) mod occ name
		  new_name_supply = name_supply {nsUniqs = us', nsNames = new_cache}


newImplicitBinder :: Name			-- Base name
	          -> (OccName -> OccName) 	-- Occurrence name modifier
	          -> TcRnIf m n Name		-- Implicit name
-- Called in BuildTyCl to allocate the implicit binders of type/class decls
-- For source type/class decls, this is the first occurrence
-- For iface ones, the LoadIface has alrady allocated a suitable name in the cache
newImplicitBinder base_name mk_sys_occ
  = newGlobalBinder (nameModule base_name)
		    (mk_sys_occ (nameOccName base_name))
		    (nameSrcSpan base_name)    

ifaceExportNames :: [IfaceExport] -> TcRnIf gbl lcl [AvailInfo]
ifaceExportNames exports = do
  mod_avails <- mapM (\(mod,avails) -> mapM (lookupAvail mod) avails) exports
  return (concat mod_avails)

-- Convert OccNames in GenAvailInfo to Names.
lookupAvail :: Module -> GenAvailInfo OccName -> TcRnIf a b AvailInfo
lookupAvail mod (Avail n) = do 
  n' <- lookupOrig mod n
  return (Avail n')
lookupAvail mod (AvailTC p_occ occs) = do
  p_name <- lookupOrig mod p_occ
  let lookup_sub occ | occ == p_occ = return p_name
                     | otherwise    = lookupOrig mod occ
  subs <- mappM lookup_sub occs
  return (AvailTC p_name subs)
	-- Remember that 'occs' is all the exported things, including
	-- the parent.  It's possible to export just class ops without
	-- the class, which shows up as C( op ) here. If the class was
	-- exported too we'd have C( C, op )

lookupOrig :: Module -> OccName ->  TcRnIf a b Name
lookupOrig mod occ
  = do 	{ 	-- First ensure that mod and occ are evaluated
		-- If not, chaos can ensue:
		-- 	we read the name-cache
		-- 	then pull on mod (say)
		--	which does some stuff that modifies the name cache
		-- This did happen, with tycon_mod in TcIface.tcIfaceAlt (DataAlt..)
	  mod `seq` occ `seq` return ()	
--	; traceIf (text "lookup_orig" <+> ppr mod <+> ppr occ)
    
	; name_cache <- getNameCache
    	; case lookupOrigNameCache (nsNames name_cache) mod occ of {
	      Just name -> returnM name;
	      Nothing   ->
              let
                us        = nsUniqs name_cache
                uniq      = uniqFromSupply us
                name      = mkExternalName uniq mod occ noSrcSpan
                new_cache = extendNameCache (nsNames name_cache) mod occ name
              in
              case splitUniqSupply us of { (us',_) -> do
                setNameCache name_cache{ nsUniqs = us', nsNames = new_cache }
                return name
    }}}

newIPName :: IPName OccName -> TcRnIf m n (IPName Name)
newIPName occ_name_ip
  = getNameCache		`thenM` \ name_supply ->
    let
	ipcache = nsIPs name_supply
    in
    case lookupFM ipcache key of
	Just name_ip -> returnM name_ip
	Nothing      -> setNameCache new_ns 	`thenM_`
		        returnM name_ip
		  where
		     (us', us1)  = splitUniqSupply (nsUniqs name_supply)
		     uniq   	 = uniqFromSupply us1
		     name_ip	 = mapIPName (mkIPName uniq) occ_name_ip
		     new_ipcache = addToFM ipcache key name_ip
		     new_ns	 = name_supply {nsUniqs = us', nsIPs = new_ipcache}
    where 
	key = occ_name_ip	-- Ensures that ?x and %x get distinct Names
\end{code}

	Local helper functions (not exported)

\begin{code}
lookupOrigNameCache :: OrigNameCache -> Module -> OccName -> Maybe Name
lookupOrigNameCache nc mod occ
  | mod == dATA_TUP || mod == gHC_PRIM,		-- Boxed tuples from one, 
    Just tup_info <- isTupleOcc_maybe occ	-- unboxed from the other
  = 	-- Special case for tuples; there are too many
	-- of them to pre-populate the original-name cache
    Just (mk_tup_name tup_info)
  where
    mk_tup_name (ns, boxity, arity)
	| ns == tcName   = tyConName (tupleTyCon boxity arity)
	| ns == dataName = dataConName (tupleCon boxity arity)
	| otherwise      = Var.varName (dataConWorkId (tupleCon boxity arity))

lookupOrigNameCache nc mod occ	-- The normal case
  = case lookupModuleEnv nc mod of
	Nothing      -> Nothing
	Just occ_env -> lookupOccEnv occ_env occ

extendOrigNameCache :: OrigNameCache -> Name -> OrigNameCache
extendOrigNameCache nc name 
  = extendNameCache nc (nameModule name) (nameOccName name) name

extendNameCache :: OrigNameCache -> Module -> OccName -> Name -> OrigNameCache
extendNameCache nc mod occ name
  = extendModuleEnv_C combine nc mod (unitOccEnv occ name)
  where
    combine occ_env _ = extendOccEnv occ_env occ name

getNameCache :: TcRnIf a b NameCache
getNameCache = do { HscEnv { hsc_NC = nc_var } <- getTopEnv; 
		    readMutVar nc_var }

setNameCache :: NameCache -> TcRnIf a b ()
setNameCache nc = do { HscEnv { hsc_NC = nc_var } <- getTopEnv; 
		       writeMutVar nc_var nc }
\end{code}


\begin{code}
initNameCache :: UniqSupply -> [Name] -> NameCache
initNameCache us names
  = NameCache { nsUniqs = us,
		nsNames = initOrigNames names,
		nsIPs   = emptyFM }

initOrigNames :: [Name] -> OrigNameCache
initOrigNames names = foldl extendOrigNameCache emptyModuleEnv names
\end{code}



%************************************************************************
%*									*
		Type variables and local Ids
%*									*
%************************************************************************

\begin{code}
tcIfaceLclId :: FastString -> IfL Id
tcIfaceLclId occ
  = do	{ lcl <- getLclEnv
	; case (lookupUFM (if_id_env lcl) occ) of
            Just ty_var -> return ty_var
            Nothing     -> failIfM (text "Iface id out of scope: " <+> ppr occ)
        }

extendIfaceIdEnv :: [Id] -> IfL a -> IfL a
extendIfaceIdEnv ids thing_inside
  = do	{ env <- getLclEnv
	; let { id_env' = addListToUFM (if_id_env env) pairs
	      ;	pairs   = [(occNameFS (getOccName id), id) | id <- ids] }
	; setLclEnv (env { if_id_env = id_env' }) thing_inside }


tcIfaceTyVar :: FastString -> IfL TyVar
tcIfaceTyVar occ
  = do	{ lcl <- getLclEnv
	; case (lookupUFM (if_tv_env lcl) occ) of
            Just ty_var -> return ty_var
            Nothing     -> failIfM (text "Iface type variable out of scope: " <+> ppr occ)
        }

extendIfaceTyVarEnv :: [TyVar] -> IfL a -> IfL a
extendIfaceTyVarEnv tyvars thing_inside
  = do	{ env <- getLclEnv
	; let { tv_env' = addListToUFM (if_tv_env env) pairs
	      ;	pairs   = [(occNameFS (getOccName tv), tv) | tv <- tyvars] }
	; setLclEnv (env { if_tv_env = tv_env' }) thing_inside }
\end{code}


%************************************************************************
%*									*
		Getting from RdrNames to Names
%*									*
%************************************************************************

\begin{code}
lookupIfaceTop :: OccName -> IfL Name
-- Look up a top-level name from the current Iface module
lookupIfaceTop occ
  = do	{ env <- getLclEnv; lookupOrig (if_mod env) occ }

newIfaceName :: OccName -> IfL Name
newIfaceName occ
  = do	{ uniq <- newUnique
	; return $! mkInternalName uniq occ noSrcSpan }

newIfaceNames :: [OccName] -> IfL [Name]
newIfaceNames occs
  = do	{ uniqs <- newUniqueSupply
	; return [ mkInternalName uniq occ noSrcSpan
		 | (occ,uniq) <- occs `zip` uniqsFromSupply uniqs] }
\end{code}

%************************************************************************
%*									*
		(Re)creating tick boxes
%*									*
%************************************************************************

\begin{code}
tcIfaceTick :: Module -> Int -> IfL Id
tcIfaceTick modName tickNo 
  = do { uniq <- newUnique
       ; return $ mkTickBoxOpId uniq modName tickNo
       }
\end{code}