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|
{-# LANGUAGE CPP #-}
module DsUsage (
-- * Dependency/fingerprinting code (used by MkIface)
mkUsageInfo, mkUsedNames, mkDependencies
) where
#include "HsVersions.h"
import DynFlags
import HscTypes
import TcRnTypes
import Name
import NameSet
import Module
import Outputable
import Util
import UniqSet
import UniqDFM
import Fingerprint
import Maybes
import Data.List
import Data.IORef
import Data.Map (Map)
import qualified Data.Map as Map
import qualified Data.Set as Set
-- | Extract information from the rename and typecheck phases to produce
-- a dependencies information for the module being compiled.
mkDependencies :: TcGblEnv -> IO Dependencies
mkDependencies
TcGblEnv{ tcg_mod = mod,
tcg_imports = imports,
tcg_th_used = th_var
}
= do
-- Template Haskell used?
th_used <- readIORef th_var
let dep_mods = eltsUDFM (delFromUDFM (imp_dep_mods imports)
(moduleName mod))
-- M.hi-boot can be in the imp_dep_mods, but we must remove
-- it before recording the modules on which this one depends!
-- (We want to retain M.hi-boot in imp_dep_mods so that
-- loadHiBootInterface can see if M's direct imports depend
-- on M.hi-boot, and hence that we should do the hi-boot consistency
-- check.)
pkgs | th_used = Set.insert (toInstalledUnitId thUnitId) (imp_dep_pkgs imports)
| otherwise = imp_dep_pkgs imports
-- Set the packages required to be Safe according to Safe Haskell.
-- See Note [RnNames . Tracking Trust Transitively]
sorted_pkgs = sort (Set.toList pkgs)
trust_pkgs = imp_trust_pkgs imports
dep_pkgs' = map (\x -> (x, x `Set.member` trust_pkgs)) sorted_pkgs
return Deps { dep_mods = dep_mods,
dep_pkgs = dep_pkgs',
dep_orphs = sortBy stableModuleCmp (imp_orphs imports),
dep_finsts = sortBy stableModuleCmp (imp_finsts imports) }
-- sort to get into canonical order
-- NB. remember to use lexicographic ordering
mkUsedNames :: TcGblEnv -> NameSet
mkUsedNames TcGblEnv{ tcg_dus = dus } = allUses dus
mkUsageInfo :: HscEnv -> Module -> ImportedMods -> NameSet -> [FilePath] -> [(Module, Fingerprint)] -> IO [Usage]
mkUsageInfo hsc_env this_mod dir_imp_mods used_names dependent_files merged
= do
eps <- hscEPS hsc_env
hashes <- mapM getFileHash dependent_files
let mod_usages = mk_mod_usage_info (eps_PIT eps) hsc_env this_mod
dir_imp_mods used_names
usages = mod_usages ++ [ UsageFile { usg_file_path = f
, usg_file_hash = hash }
| (f, hash) <- zip dependent_files hashes ]
++ [ UsageMergedRequirement
{ usg_mod = mod,
usg_mod_hash = hash
}
| (mod, hash) <- merged ]
usages `seqList` return usages
-- seq the list of Usages returned: occasionally these
-- don't get evaluated for a while and we can end up hanging on to
-- the entire collection of Ifaces.
mk_mod_usage_info :: PackageIfaceTable
-> HscEnv
-> Module
-> ImportedMods
-> NameSet
-> [Usage]
mk_mod_usage_info pit hsc_env this_mod direct_imports used_names
= mapMaybe mkUsage usage_mods
where
hpt = hsc_HPT hsc_env
dflags = hsc_dflags hsc_env
this_pkg = thisPackage dflags
used_mods = moduleEnvKeys ent_map
dir_imp_mods = moduleEnvKeys direct_imports
all_mods = used_mods ++ filter (`notElem` used_mods) dir_imp_mods
usage_mods = sortBy stableModuleCmp all_mods
-- canonical order is imported, to avoid interface-file
-- wobblage.
-- ent_map groups together all the things imported and used
-- from a particular module
ent_map :: ModuleEnv [OccName]
ent_map = nonDetFoldUniqSet add_mv emptyModuleEnv used_names
-- nonDetFoldUFM is OK here. If you follow the logic, we sort by OccName
-- in ent_hashs
where
add_mv name mv_map
| isWiredInName name = mv_map -- ignore wired-in names
| otherwise
= case nameModule_maybe name of
Nothing -> ASSERT2( isSystemName name, ppr name ) mv_map
-- See Note [Internal used_names]
Just mod ->
-- See Note [Identity versus semantic module]
let mod' = if isHoleModule mod
then mkModule this_pkg (moduleName mod)
else mod
-- This lambda function is really just a
-- specialised (++); originally came about to
-- avoid quadratic behaviour (trac #2680)
in extendModuleEnvWith (\_ xs -> occ:xs) mv_map mod' [occ]
where occ = nameOccName name
-- We want to create a Usage for a home module if
-- a) we used something from it; has something in used_names
-- b) we imported it, even if we used nothing from it
-- (need to recompile if its export list changes: export_fprint)
mkUsage :: Module -> Maybe Usage
mkUsage mod
| isNothing maybe_iface -- We can't depend on it if we didn't
-- load its interface.
|| mod == this_mod -- We don't care about usages of
-- things in *this* module
= Nothing
| moduleUnitId mod /= this_pkg
= Just UsagePackageModule{ usg_mod = mod,
usg_mod_hash = mod_hash,
usg_safe = imp_safe }
-- for package modules, we record the module hash only
| (null used_occs
&& isNothing export_hash
&& not is_direct_import
&& not finsts_mod)
= Nothing -- Record no usage info
-- for directly-imported modules, we always want to record a usage
-- on the orphan hash. This is what triggers a recompilation if
-- an orphan is added or removed somewhere below us in the future.
| otherwise
= Just UsageHomeModule {
usg_mod_name = moduleName mod,
usg_mod_hash = mod_hash,
usg_exports = export_hash,
usg_entities = Map.toList ent_hashs,
usg_safe = imp_safe }
where
maybe_iface = lookupIfaceByModule dflags hpt pit mod
-- In one-shot mode, the interfaces for home-package
-- modules accumulate in the PIT not HPT. Sigh.
Just iface = maybe_iface
finsts_mod = mi_finsts iface
hash_env = mi_hash_fn iface
mod_hash = mi_mod_hash iface
export_hash | depend_on_exports = Just (mi_exp_hash iface)
| otherwise = Nothing
(is_direct_import, imp_safe)
= case lookupModuleEnv direct_imports mod of
Just (imv : _xs) -> (True, imv_is_safe imv)
Just _ -> pprPanic "mkUsage: empty direct import" Outputable.empty
Nothing -> (False, safeImplicitImpsReq dflags)
-- Nothing case is for implicit imports like 'System.IO' when 'putStrLn'
-- is used in the source code. We require them to be safe in Safe Haskell
used_occs = lookupModuleEnv ent_map mod `orElse` []
-- Making a Map here ensures that (a) we remove duplicates
-- when we have usages on several subordinates of a single parent,
-- and (b) that the usages emerge in a canonical order, which
-- is why we use Map rather than OccEnv: Map works
-- using Ord on the OccNames, which is a lexicographic ordering.
ent_hashs :: Map OccName Fingerprint
ent_hashs = Map.fromList (map lookup_occ used_occs)
lookup_occ occ =
case hash_env occ of
Nothing -> pprPanic "mkUsage" (ppr mod <+> ppr occ <+> ppr used_names)
Just r -> r
depend_on_exports = is_direct_import
{- True
Even if we used 'import M ()', we have to register a
usage on the export list because we are sensitive to
changes in orphan instances/rules.
False
In GHC 6.8.x we always returned true, and in
fact it recorded a dependency on *all* the
modules underneath in the dependency tree. This
happens to make orphans work right, but is too
expensive: it'll read too many interface files.
The 'isNothing maybe_iface' check above saved us
from generating many of these usages (at least in
one-shot mode), but that's even more bogus!
-}
|
