+-- | A compilation target.
+--
+-- A target may be supplied with the actual text of the
+-- module. If so, use this instead of the file contents (this
+-- is for use in an IDE where the file hasn't been saved by
+-- the user yet).
+data Target = Target TargetId (Maybe (StringBuffer,ClockTime))
+
+data TargetId
+ = TargetModule Module
+ -- ^ A module name: search for the file
+ | TargetFile FilePath (Maybe Phase)
+ -- ^ A filename: preprocess & parse it to find the module name.
+ -- If specified, the Phase indicates how to compile this file
+ -- (which phase to start from). Nothing indicates the starting phase
+ -- should be determined from the suffix of the filename.
+ deriving Eq
+
+pprTarget :: Target -> SDoc
+pprTarget (Target id _) = pprTargetId id
+
+pprTargetId (TargetModule m) = ppr m
+pprTargetId (TargetFile f _) = text f
+
+type FinderCache = ModuleEnv FinderCacheEntry
+type FinderCacheEntry = (ModLocation, Maybe (PackageConfig,Bool))
+ -- The finder's cache (see module Finder)
+
+type HomePackageTable = ModuleEnv HomeModInfo
+ -- Domain = modules in the home package
+type PackageIfaceTable = ModuleEnv ModIface
+ -- Domain = modules in the imported packages
+
+emptyHomePackageTable = emptyModuleEnv
+emptyPackageIfaceTable = emptyModuleEnv
+
+data HomeModInfo
+ = HomeModInfo { hm_iface :: !ModIface,
+ hm_details :: !ModDetails,
+ hm_linkable :: !(Maybe Linkable) }
+ -- hm_linkable might be Nothing if:
+ -- a) this is an .hs-boot module
+ -- b) temporarily during compilation if we pruned away
+ -- the old linkable because it was out of date.
+ -- after a complete compilation (GHC.load), all hm_linkable
+ -- fields in the HPT will be Just.
+ --
+ -- When re-linking a module (hscNoRecomp), we construct
+ -- the HomModInfo by building a new ModDetails from the
+ -- old ModIface (only).
+\end{code}
+
+Simple lookups in the symbol table.
+
+\begin{code}
+lookupIface :: HomePackageTable -> PackageIfaceTable -> Module -> Maybe ModIface
+-- We often have two IfaceTables, and want to do a lookup
+lookupIface hpt pit mod
+ = case lookupModuleEnv hpt mod of
+ Just mod_info -> Just (hm_iface mod_info)
+ Nothing -> lookupModuleEnv pit mod
+
+lookupIfaceByModule :: HomePackageTable -> PackageIfaceTable -> Module -> Maybe ModIface
+-- We often have two IfaceTables, and want to do a lookup
+lookupIfaceByModule hpt pit mod
+ = case lookupModuleEnv hpt mod of
+ Just mod_info -> Just (hm_iface mod_info)
+ Nothing -> lookupModuleEnv pit mod