HscMain.hs 74 KB
Newer Older
1
{-# LANGUAGE BangPatterns, CPP, MagicHash, NondecreasingIndentation #-}
Simon Marlow's avatar
Simon Marlow committed
2
{-# OPTIONS_GHC -fprof-auto-top #-}
3

dterei's avatar
dterei committed
4 5
-------------------------------------------------------------------------------
--
6
-- | Main API for compiling plain Haskell source code.
7
--
dterei's avatar
dterei committed
8
-- This module implements compilation of a Haskell source. It is
9 10 11 12 13
-- /not/ concerned with preprocessing of source files; this is handled
-- in "DriverPipeline".
--
-- There are various entry points depending on what mode we're in:
-- "batch" mode (@--make@), "one-shot" mode (@-c@, @-S@ etc.), and
dterei's avatar
dterei committed
14
-- "interactive" mode (GHCi). There are also entry points for
15 16 17 18 19 20 21 22
-- individual passes: parsing, typechecking/renaming, desugaring, and
-- simplification.
--
-- All the functions here take an 'HscEnv' as a parameter, but none of
-- them return a new one: 'HscEnv' is treated as an immutable value
-- from here on in (although it has mutable components, for the
-- caches).
--
23 24 25 26 27
-- We use the Hsc monad to deal with warning messages consistently:
-- specifically, while executing within an Hsc monad, warnings are
-- collected. When a Hsc monad returns to an IO monad, the
-- warnings are printed, or compilation aborts if the @-Werror@
-- flag is enabled.
28
--
dterei's avatar
dterei committed
29 30 31 32
-- (c) The GRASP/AQUA Project, Glasgow University, 1993-2000
--
-------------------------------------------------------------------------------

33
module HscMain
dterei's avatar
dterei committed
34
    (
35 36 37 38
    -- * Making an HscEnv
      newHscEnv

    -- * Compiling complete source files
39 40
    , Messager, batchMsg
    , HscStatus (..)
41
    , hscIncrementalCompile
42 43
    , hscCompileCmmFile

44 45 46
    , hscGenHardCode
    , hscInteractive

47
    -- * Running passes separately
Thomas Schilling's avatar
Thomas Schilling committed
48 49 50
    , hscParse
    , hscTypecheckRename
    , hscDesugar
Simon Marlow's avatar
Simon Marlow committed
51
    , makeSimpleDetails
52 53
    , hscSimplify -- ToDo, shouldn't really export this

54 55 56 57
    -- * Safe Haskell
    , hscCheckSafe
    , hscGetSafe

58 59 60 61
    -- * Support for interactive evaluation
    , hscParseIdentifier
    , hscTcRcLookupName
    , hscTcRnGetInfo
dterei's avatar
dterei committed
62
    , hscIsGHCiMonad
63
    , hscGetModuleInterface
64
    , hscRnImportDecls
65
    , hscTcRnLookupRdrName
66
    , hscStmt, hscStmtWithLocation, hscParsedStmt
67
    , hscDecls, hscDeclsWithLocation
68
    , hscTcExpr, TcRnExprMode(..), hscImport, hscKcType
69
    , hscParseExpr
70
    , hscCompileCoreExpr
71 72
    -- * Low-level exports for hooks
    , hscCompileCoreExpr'
Edsko de Vries's avatar
Edsko de Vries committed
73 74
      -- We want to make sure that we export enough to be able to redefine
      -- hscFileFrontEnd in client code
75
    , hscParse', hscSimplify', hscDesugar', tcRnModule'
Edsko de Vries's avatar
Edsko de Vries committed
76
    , getHscEnv
77 78 79
    , hscSimpleIface', hscNormalIface'
    , oneShotMsg
    , hscFileFrontEnd, genericHscFrontend, dumpIfaceStats
Edward Z. Yang's avatar
Edward Z. Yang committed
80 81
    , ioMsgMaybe
    , showModuleIndex
82
    , hscAddSptEntries
83
    ) where
84

85 86
import GhcPrelude

87
import Data.Data hiding (Fixity, TyCon)
88
import DynFlags         (addPluginModuleName)
Simon Marlow's avatar
Simon Marlow committed
89
import Id
90
import GHCi             ( addSptEntry )
91
import GHCi.RemoteTypes ( ForeignHValue )
92
import ByteCodeGen      ( byteCodeGen, coreExprToBCOs )
93
import Linker
94
import CoreTidy         ( tidyExpr )
95 96
import Type             ( Type )
import {- Kind parts of -} Type         ( Kind )
97
import CoreLint         ( lintInteractiveExpr )
98
import VarEnv           ( emptyTidyEnv )
99
import Panic
100
import ConLike
101
import Control.Concurrent
102

alexbiehl's avatar
alexbiehl committed
103
import Avail            ( Avails )
104 105
import Module
import Packages
Simon Marlow's avatar
Simon Marlow committed
106 107
import RdrName
import HsSyn
108
import HsDumpAst
109
import CoreSyn
Ian Lynagh's avatar
Ian Lynagh committed
110
import StringBuffer
111
import Parser
112
import Lexer
113 114
import SrcLoc
import TcRnDriver
115
import TcIface          ( typecheckIface )
116
import TcRnMonad
117
import NameCache        ( initNameCache )
118
import LoadIface        ( ifaceStats, initExternalPackageState )
119
import PrelInfo
Simon Marlow's avatar
Simon Marlow committed
120
import MkIface
121 122
import Desugar
import SimplCore
Simon Marlow's avatar
Simon Marlow committed
123
import TidyPgm
124
import CorePrep
125 126
import CoreToStg        ( coreToStg )
import qualified StgCmm ( codeGen )
127 128
import StgSyn
import CostCentre
129
import ProfInit
130 131
import TyCon
import Name
132
import SimplStg         ( stg2stg )
133
import Cmm
134
import CmmParse         ( parseCmmFile )
135
import CmmBuildInfoTables
Edward Z. Yang's avatar
Edward Z. Yang committed
136
import CmmPipeline
137
import CmmInfo
138 139
import CodeOutput
import InstEnv
140
import FamInstEnv
Thomas Schilling's avatar
Thomas Schilling committed
141
import Fingerprint      ( Fingerprint )
142
import Hooks
Edward Z. Yang's avatar
Edward Z. Yang committed
143
import TcEnv
144
import PrelNames
145

146
import DynFlags
147
import ErrUtils
148
import Platform ( platformOS, osSubsectionsViaSymbols )
149

150
import Outputable
eir@cis.upenn.edu's avatar
eir@cis.upenn.edu committed
151
import NameEnv
152
import HscStats         ( ppSourceStats )
153
import HscTypes
154
import FastString
155
import UniqSupply
156
import Bag
Thomas Schilling's avatar
Thomas Schilling committed
157
import Exception
158 159 160
import qualified Stream
import Stream (Stream)

161
import Util
Simon Marlow's avatar
Simon Marlow committed
162

163
import Data.List
Simon Marlow's avatar
Simon Marlow committed
164 165
import Control.Monad
import Data.IORef
166
import System.FilePath as FilePath
167
import System.Directory
168
import System.IO (fixIO)
Alan Zimmerman's avatar
Alan Zimmerman committed
169
import qualified Data.Map as Map
170 171
import qualified Data.Set as S
import Data.Set (Set)
dterei's avatar
dterei committed
172

Thomas Schilling's avatar
Thomas Schilling committed
173
#include "HsVersions.h"
174

175

dterei's avatar
dterei committed
176 177 178 179 180
{- **********************************************************************
%*                                                                      *
                Initialisation
%*                                                                      *
%********************************************************************* -}
181

182
newHscEnv :: DynFlags -> IO HscEnv
183
newHscEnv dflags = do
dterei's avatar
dterei committed
184 185
    eps_var <- newIORef initExternalPackageState
    us      <- mkSplitUniqSupply 'r'
186
    nc_var  <- newIORef (initNameCache us knownKeyNames)
187
    fc_var  <- newIORef emptyInstalledModuleEnv
188 189 190
    iserv_mvar <- newMVar Nothing
    return HscEnv {  hsc_dflags       = dflags
                  ,  hsc_targets      = []
191
                  ,  hsc_mod_graph    = emptyMG
192 193 194 195 196 197 198 199
                  ,  hsc_IC           = emptyInteractiveContext dflags
                  ,  hsc_HPT          = emptyHomePackageTable
                  ,  hsc_EPS          = eps_var
                  ,  hsc_NC           = nc_var
                  ,  hsc_FC           = fc_var
                  ,  hsc_type_env_var = Nothing
                  , hsc_iserv        = iserv_mvar
                  }
Thomas Schilling's avatar
Thomas Schilling committed
200

201
-- -----------------------------------------------------------------------------
202

203
getWarnings :: Hsc WarningMessages
dterei's avatar
dterei committed
204
getWarnings = Hsc $ \_ w -> return (w, w)
205 206

clearWarnings :: Hsc ()
dterei's avatar
dterei committed
207
clearWarnings = Hsc $ \_ _ -> return ((), emptyBag)
208 209

logWarnings :: WarningMessages -> Hsc ()
dterei's avatar
dterei committed
210
logWarnings w = Hsc $ \_ w0 -> return ((), w0 `unionBags` w)
211 212

getHscEnv :: Hsc HscEnv
dterei's avatar
dterei committed
213
getHscEnv = Hsc $ \e w -> return (e, w)
214 215 216

handleWarnings :: Hsc ()
handleWarnings = do
dterei's avatar
dterei committed
217 218 219 220
    dflags <- getDynFlags
    w <- getWarnings
    liftIO $ printOrThrowWarnings dflags w
    clearWarnings
221 222 223 224 225

-- | log warning in the monad, and if there are errors then
-- throw a SourceError exception.
logWarningsReportErrors :: Messages -> Hsc ()
logWarningsReportErrors (warns,errs) = do
dterei's avatar
dterei committed
226 227
    logWarnings warns
    when (not $ isEmptyBag errs) $ throwErrors errs
228 229 230 231

-- | Throw some errors.
throwErrors :: ErrorMessages -> Hsc a
throwErrors = liftIO . throwIO . mkSrcErr
232 233 234 235 236

-- | Deal with errors and warnings returned by a compilation step
--
-- In order to reduce dependencies to other parts of the compiler, functions
-- outside the "main" parts of GHC return warnings and errors as a parameter
dterei's avatar
dterei committed
237
-- and signal success via by wrapping the result in a 'Maybe' type. This
238 239 240 241 242 243 244 245 246
-- function logs the returned warnings and propagates errors as exceptions
-- (of type 'SourceError').
--
-- This function assumes the following invariants:
--
--  1. If the second result indicates success (is of the form 'Just x'),
--     there must be no error messages in the first result.
--
--  2. If there are no error messages, but the second result indicates failure
dterei's avatar
dterei committed
247
--     there should be warnings in the first result. That is, if the action
248 249 250
--     failed, it must have been due to the warnings (i.e., @-Werror@).
ioMsgMaybe :: IO (Messages, Maybe a) -> Hsc a
ioMsgMaybe ioA = do
251
    ((warns,errs), mb_r) <- liftIO ioA
dterei's avatar
dterei committed
252 253 254 255
    logWarnings warns
    case mb_r of
        Nothing -> throwErrors errs
        Just r  -> ASSERT( isEmptyBag errs ) return r
256 257 258 259 260

-- | like ioMsgMaybe, except that we ignore error messages and return
-- 'Nothing' instead.
ioMsgMaybe' :: IO (Messages, Maybe a) -> Hsc (Maybe a)
ioMsgMaybe' ioA = do
dterei's avatar
dterei committed
261 262 263
    ((warns,_errs), mb_r) <- liftIO $ ioA
    logWarnings warns
    return mb_r
264 265 266 267

-- -----------------------------------------------------------------------------
-- | Lookup things in the compiler's environment

268
hscTcRnLookupRdrName :: HscEnv -> Located RdrName -> IO [Name]
269 270
hscTcRnLookupRdrName hsc_env0 rdr_name
  = runInteractiveHsc hsc_env0 $
271 272
    do { hsc_env <- getHscEnv
       ; ioMsgMaybe $ tcRnLookupRdrName hsc_env rdr_name }
273 274

hscTcRcLookupName :: HscEnv -> Name -> IO (Maybe TyThing)
275 276 277
hscTcRcLookupName hsc_env0 name = runInteractiveHsc hsc_env0 $ do
  hsc_env <- getHscEnv
  ioMsgMaybe' $ tcRnLookupName hsc_env name
dterei's avatar
dterei committed
278 279 280
      -- ignore errors: the only error we're likely to get is
      -- "name not found", and the Maybe in the return type
      -- is used to indicate that.
281

282 283
hscTcRnGetInfo :: HscEnv -> Name
               -> IO (Maybe (TyThing, Fixity, [ClsInst], [FamInst], SDoc))
284 285 286 287
hscTcRnGetInfo hsc_env0 name
  = runInteractiveHsc hsc_env0 $
    do { hsc_env <- getHscEnv
       ; ioMsgMaybe' $ tcRnGetInfo hsc_env name }
288

dterei's avatar
dterei committed
289
hscIsGHCiMonad :: HscEnv -> String -> IO Name
Edsko de Vries's avatar
Edsko de Vries committed
290
hscIsGHCiMonad hsc_env name
291
  = runHsc hsc_env $ ioMsgMaybe $ isGHCiMonad hsc_env name
dterei's avatar
dterei committed
292

293
hscGetModuleInterface :: HscEnv -> Module -> IO ModIface
294 295 296
hscGetModuleInterface hsc_env0 mod = runInteractiveHsc hsc_env0 $ do
  hsc_env <- getHscEnv
  ioMsgMaybe $ getModuleInterface hsc_env mod
297 298 299

-- -----------------------------------------------------------------------------
-- | Rename some import declarations
300
hscRnImportDecls :: HscEnv -> [LImportDecl GhcPs] -> IO GlobalRdrEnv
301 302 303
hscRnImportDecls hsc_env0 import_decls = runInteractiveHsc hsc_env0 $ do
  hsc_env <- getHscEnv
  ioMsgMaybe $ tcRnImportDecls hsc_env import_decls
304

305
-- -----------------------------------------------------------------------------
Simon Marlow's avatar
Simon Marlow committed
306
-- | parse a file, returning the abstract syntax
307

308
hscParse :: HscEnv -> ModSummary -> IO HsParsedModule
309 310 311
hscParse hsc_env mod_summary = runHsc hsc_env $ hscParse' mod_summary

-- internal version, that doesn't fail due to -Werror
312
hscParse' :: ModSummary -> Hsc HsParsedModule
Edward Z. Yang's avatar
Edward Z. Yang committed
313 314 315
hscParse' mod_summary
 | Just r <- ms_parsed_mod mod_summary = return r
 | otherwise = {-# SCC "Parser" #-}
316 317 318
    withTiming getDynFlags
               (text "Parser"<+>brackets (ppr $ ms_mod mod_summary))
               (const ()) $ do
dterei's avatar
dterei committed
319 320 321
    dflags <- getDynFlags
    let src_filename  = ms_hspp_file mod_summary
        maybe_src_buf = ms_hspp_buf  mod_summary
322

dterei's avatar
dterei committed
323
    --------------------------  Parser  ----------------
324 325 326
    -- sometimes we already have the buffer in memory, perhaps
    -- because we needed to parse the imports out of it, or get the
    -- module name.
dterei's avatar
dterei committed
327 328 329
    buf <- case maybe_src_buf of
               Just b  -> return b
               Nothing -> liftIO $ hGetStringBuffer src_filename
330

dterei's avatar
dterei committed
331
    let loc = mkRealSrcLoc (mkFastString src_filename) 1 1
Edward Z. Yang's avatar
Edward Z. Yang committed
332 333 334
    let parseMod | HsigFile == ms_hsc_src mod_summary
                 = parseSignature
                 | otherwise = parseModule
335

Edward Z. Yang's avatar
Edward Z. Yang committed
336
    case unP parseMod (mkPState dflags buf loc) of
337 338 339
        PFailed warnFn span err -> do
            logWarningsReportErrors (warnFn dflags)
            handleWarnings
Ian Lynagh's avatar
Ian Lynagh committed
340
            liftIO $ throwOneError (mkPlainErrMsg dflags span err)
341

dterei's avatar
dterei committed
342
        POk pst rdr_module -> do
343
            logWarningsReportErrors (getMessages pst dflags)
dterei's avatar
dterei committed
344 345
            liftIO $ dumpIfSet_dyn dflags Opt_D_dump_parsed "Parser" $
                                   ppr rdr_module
346
            liftIO $ dumpIfSet_dyn dflags Opt_D_dump_parsed_ast "Parser AST" $
347
                                   showAstData NoBlankSrcSpan rdr_module
dterei's avatar
dterei committed
348 349
            liftIO $ dumpIfSet_dyn dflags Opt_D_source_stats "Source Statistics" $
                                   ppSourceStats False rdr_module
350 351 352 353 354

            -- To get the list of extra source files, we take the list
            -- that the parser gave us,
            --   - eliminate files beginning with '<'.  gcc likes to use
            --     pseudo-filenames like "<built-in>" and "<command-line>"
Gabor Greif's avatar
Gabor Greif committed
355
            --   - normalise them (eliminate differences between ./f and f)
356 357 358 359 360 361 362 363 364
            --   - filter out the preprocessed source file
            --   - filter out anything beginning with tmpdir
            --   - remove duplicates
            --   - filter out the .hs/.lhs source filename if we have one
            --
            let n_hspp  = FilePath.normalise src_filename
                srcs0 = nub $ filter (not . (tmpDir dflags `isPrefixOf`))
                            $ filter (not . (== n_hspp))
                            $ map FilePath.normalise
365
                            $ filter (not . (isPrefixOf "<"))
366 367 368 369 370 371
                            $ map unpackFS
                            $ srcfiles pst
                srcs1 = case ml_hs_file (ms_location mod_summary) of
                          Just f  -> filter (/= FilePath.normalise f) srcs0
                          Nothing -> srcs0

372 373 374 375 376
            -- sometimes we see source files from earlier
            -- preprocessing stages that cannot be found, so just
            -- filter them out:
            srcs2 <- liftIO $ filterM doesFileExist srcs1

377 378
            return HsParsedModule {
                      hpm_module    = rdr_module,
Alan Zimmerman's avatar
Alan Zimmerman committed
379 380 381 382 383
                      hpm_src_files = srcs2,
                      hpm_annotations
                              = (Map.fromListWith (++) $ annotations pst,
                                 Map.fromList $ ((noSrcSpan,comment_q pst)
                                                 :(annotations_comments pst)))
384
                   }
Simon Marlow's avatar
Simon Marlow committed
385

Thomas Schilling's avatar
Thomas Schilling committed
386 387 388
-- XXX: should this really be a Maybe X?  Check under which circumstances this
-- can become a Nothing and decide whether this should instead throw an
-- exception/signal an error.
dterei's avatar
dterei committed
389
type RenamedStuff =
alexbiehl's avatar
alexbiehl committed
390
        (Maybe (HsGroup GhcRn, [LImportDecl GhcRn], Maybe [(LIE GhcRn, Avails)],
391
                Maybe LHsDocString))
Simon Marlow's avatar
Simon Marlow committed
392

393 394 395 396
-- -----------------------------------------------------------------------------
-- | If the renamed source has been kept, extract it. Dump it if requested.
extract_renamed_stuff :: TcGblEnv -> Hsc (TcGblEnv, RenamedStuff)
extract_renamed_stuff tc_result = do
Thomas Schilling's avatar
Thomas Schilling committed
397

398
    -- This 'do' is in the Maybe monad!
399 400 401 402 403
    let rn_info = do decl <- tcg_rn_decls tc_result
                     let imports = tcg_rn_imports tc_result
                         exports = tcg_rn_exports tc_result
                         doc_hdr = tcg_doc_hdr tc_result
                     return (decl,imports,exports,doc_hdr)
Thomas Schilling's avatar
Thomas Schilling committed
404

405 406 407 408
    dflags <- getDynFlags
    liftIO $ dumpIfSet_dyn dflags Opt_D_dump_rn_ast "Renamer" $
                           showAstData NoBlankSrcSpan rn_info

409
    return (tc_result, rn_info)
Simon Marlow's avatar
Simon Marlow committed
410

411 412 413 414 415 416 417 418 419 420

-- -----------------------------------------------------------------------------
-- | Rename and typecheck a module, additionally returning the renamed syntax
hscTypecheckRename :: HscEnv -> ModSummary -> HsParsedModule
                   -> IO (TcGblEnv, RenamedStuff)
hscTypecheckRename hsc_env mod_summary rdr_module = runHsc hsc_env $ do
    tc_result <- hscTypecheck True mod_summary (Just rdr_module)
    extract_renamed_stuff tc_result


Edward Z. Yang's avatar
Edward Z. Yang committed
421 422 423 424
hscTypecheck :: Bool -- ^ Keep renamed source?
             -> ModSummary -> Maybe HsParsedModule
             -> Hsc TcGblEnv
hscTypecheck keep_rn mod_summary mb_rdr_module = do
425 426 427 428 429 430 431 432 433
    tc_result <- hscTypecheck' keep_rn mod_summary mb_rdr_module
    _ <- extract_renamed_stuff tc_result
    return tc_result


hscTypecheck' :: Bool -- ^ Keep renamed source?
              -> ModSummary -> Maybe HsParsedModule
              -> Hsc TcGblEnv
hscTypecheck' keep_rn mod_summary mb_rdr_module = do
Edward Z. Yang's avatar
Edward Z. Yang committed
434 435 436 437
    hsc_env <- getHscEnv
    let hsc_src = ms_hsc_src mod_summary
        dflags = hsc_dflags hsc_env
        outer_mod = ms_mod mod_summary
438 439 440
        mod_name = moduleName outer_mod
        outer_mod' = mkModule (thisPackage dflags) mod_name
        inner_mod = canonicalizeHomeModule dflags mod_name
Edward Z. Yang's avatar
Edward Z. Yang committed
441 442 443 444
        src_filename  = ms_hspp_file mod_summary
        real_loc = realSrcLocSpan $ mkRealSrcLoc (mkFastString src_filename) 1 1
    MASSERT( moduleUnitId outer_mod == thisPackage dflags )
    if hsc_src == HsigFile && not (isHoleModule inner_mod)
445
        then ioMsgMaybe $ tcRnInstantiateSignature hsc_env outer_mod' real_loc
Edward Z. Yang's avatar
Edward Z. Yang committed
446 447 448 449
        else
         do hpm <- case mb_rdr_module of
                    Just hpm -> return hpm
                    Nothing -> hscParse' mod_summary
450
            tc_result0 <- tcRnModule' mod_summary keep_rn hpm
Edward Z. Yang's avatar
Edward Z. Yang committed
451 452 453
            if hsc_src == HsigFile
                then do (iface, _, _) <- liftIO $ hscSimpleIface hsc_env tc_result0 Nothing
                        ioMsgMaybe $
454
                            tcRnMergeSignatures hsc_env hpm tc_result0 iface
Edward Z. Yang's avatar
Edward Z. Yang committed
455 456
                else return tc_result0

457
-- wrapper around tcRnModule to handle safe haskell extras
458
tcRnModule' :: ModSummary -> Bool -> HsParsedModule
459
            -> Hsc TcGblEnv
460 461
tcRnModule' sum save_rn_syntax mod = do
    hsc_env <- getHscEnv
462 463 464 465
    tcg_res <- {-# SCC "Typecheck-Rename" #-}
               ioMsgMaybe $
                   tcRnModule hsc_env (ms_hsc_src sum) save_rn_syntax mod

466 467 468
    -- See Note [Safe Haskell Overlapping Instances Implementation]
    -- although this is used for more than just that failure case.
    (tcSafeOK, whyUnsafe) <- liftIO $ readIORef (tcg_safeInfer tcg_res)
469
    dflags   <- getDynFlags
470
    let allSafeOK = safeInferred dflags && tcSafeOK
471

472 473 474
    -- end of the safe haskell line, how to respond to user?
    if not (safeHaskellOn dflags) || (safeInferOn dflags && not allSafeOK)
        -- if safe Haskell off or safe infer failed, mark unsafe
475
        then markUnsafeInfer tcg_res whyUnsafe
476

477
        -- module (could be) safe, throw warning if needed
478 479
        else do
            tcg_res' <- hscCheckSafeImports tcg_res
480
            safe <- liftIO $ fst <$> readIORef (tcg_safeInfer tcg_res')
481 482
            when safe $ do
              case wopt Opt_WarnSafe dflags of
483 484 485 486
                True -> (logWarnings $ unitBag $
                         makeIntoWarning (Reason Opt_WarnSafe) $
                         mkPlainWarnMsg dflags (warnSafeOnLoc dflags) $
                         errSafe tcg_res')
487 488
                False | safeHaskell dflags == Sf_Trustworthy &&
                        wopt Opt_WarnTrustworthySafe dflags ->
489 490 491 492
                        (logWarnings $ unitBag $
                         makeIntoWarning (Reason Opt_WarnTrustworthySafe) $
                         mkPlainWarnMsg dflags (trustworthyOnLoc dflags) $
                         errTwthySafe tcg_res')
493
                False -> return ()
494 495 496
            return tcg_res'
  where
    pprMod t  = ppr $ moduleName $ tcg_mod t
497
    errSafe t = quotes (pprMod t) <+> text "has been inferred as safe!"
498 499
    errTwthySafe t = quotes (pprMod t)
      <+> text "is marked as Trustworthy but has been inferred as safe!"
500

Simon Marlow's avatar
Simon Marlow committed
501
-- | Convert a typechecked module to Core
502
hscDesugar :: HscEnv -> ModSummary -> TcGblEnv -> IO ModGuts
503
hscDesugar hsc_env mod_summary tc_result =
Ian Lynagh's avatar
Ian Lynagh committed
504
    runHsc hsc_env $ hscDesugar' (ms_location mod_summary) tc_result
505

Ian Lynagh's avatar
Ian Lynagh committed
506 507
hscDesugar' :: ModLocation -> TcGblEnv -> Hsc ModGuts
hscDesugar' mod_location tc_result = do
dterei's avatar
dterei committed
508
    hsc_env <- getHscEnv
Simon Marlow's avatar
Simon Marlow committed
509 510
    r <- ioMsgMaybe $
      {-# SCC "deSugar" #-}
Ian Lynagh's avatar
Ian Lynagh committed
511
      deSugar hsc_env mod_location tc_result
512

dterei's avatar
dterei committed
513 514 515 516
    -- always check -Werror after desugaring, this is the last opportunity for
    -- warnings to arise before the backend.
    handleWarnings
    return r
Simon Marlow's avatar
Simon Marlow committed
517

dterei's avatar
dterei committed
518
-- | Make a 'ModDetails' from the results of typechecking. Used when
Simon Marlow's avatar
Simon Marlow committed
519
-- typechecking only, as opposed to full compilation.
520 521
makeSimpleDetails :: HscEnv -> TcGblEnv -> IO ModDetails
makeSimpleDetails hsc_env tc_result = mkBootModDetailsTc hsc_env tc_result
Simon Marlow's avatar
Simon Marlow committed
522

523

dterei's avatar
dterei committed
524 525 526 527 528 529 530
{- **********************************************************************
%*                                                                      *
                The main compiler pipeline
%*                                                                      *
%********************************************************************* -}

{-
531 532 533 534
                   --------------------------------
                        The compilation proper
                   --------------------------------

dterei's avatar
dterei committed
535 536 537 538 539 540
It's the task of the compilation proper to compile Haskell, hs-boot and core
files to either byte-code, hard-code (C, asm, LLVM, ect) or to nothing at all
(the module is still parsed and type-checked. This feature is mostly used by
IDE's and the likes). Compilation can happen in either 'one-shot', 'batch',
'nothing', or 'interactive' mode. 'One-shot' mode targets hard-code, 'batch'
mode targets hard-code, 'nothing' mode targets nothing and 'interactive' mode
541
targets byte-code.
dterei's avatar
dterei committed
542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566

The modes are kept separate because of their different types and meanings:

 * In 'one-shot' mode, we're only compiling a single file and can therefore
 discard the new ModIface and ModDetails. This is also the reason it only
 targets hard-code; compiling to byte-code or nothing doesn't make sense when
 we discard the result.

 * 'Batch' mode is like 'one-shot' except that we keep the resulting ModIface
 and ModDetails. 'Batch' mode doesn't target byte-code since that require us to
 return the newly compiled byte-code.

 * 'Nothing' mode has exactly the same type as 'batch' mode but they're still
 kept separate. This is because compiling to nothing is fairly special: We
 don't output any interface files, we don't run the simplifier and we don't
 generate any code.

 * 'Interactive' mode is similar to 'batch' mode except that we return the
 compiled byte-code together with the ModIface and ModDetails.

Trying to compile a hs-boot file to byte-code will result in a run-time error.
This is the only thing that isn't caught by the type-system.
-}


567 568
type Messager = HscEnv -> (Int,Int) -> RecompileRequired -> ModSummary -> IO ()

569 570 571 572 573 574 575 576 577 578 579 580 581 582 583
-- | This function runs GHC's frontend with recompilation
-- avoidance. Specifically, it checks if recompilation is needed,
-- and if it is, it parses and typechecks the input module.
-- It does not write out the results of typechecking (See
-- compileOne and hscIncrementalCompile).
hscIncrementalFrontend :: Bool -- always do basic recompilation check?
                       -> Maybe TcGblEnv
                       -> Maybe Messager
                       -> ModSummary
                       -> SourceModified
                       -> Maybe ModIface  -- Old interface, if available
                       -> (Int,Int)       -- (i,n) = module i of n (for msgs)
                       -> Hsc (Either ModIface (FrontendResult, Maybe Fingerprint))

hscIncrementalFrontend
Simon Marlow's avatar
Simon Marlow committed
584
  always_do_basic_recompilation_check m_tc_result
585
  mHscMessage mod_summary source_modified mb_old_iface mod_index
586
    = do
587
    hsc_env <- getHscEnv
588 589 590 591

    let msg what = case mHscMessage of
                   Just hscMessage -> hscMessage hsc_env mod_index what mod_summary
                   Nothing -> return ()
dterei's avatar
dterei committed
592

593
        skip iface = do
594
            liftIO $ msg UpToDate
595
            return $ Left iface
dterei's avatar
dterei committed
596

597
        compile mb_old_hash reason = do
598 599 600
            liftIO $ msg reason
            result <- genericHscFrontend mod_summary
            return $ Right (result, mb_old_hash)
dterei's avatar
dterei committed
601 602 603 604

        stable = case source_modified of
                     SourceUnmodifiedAndStable -> True
                     _                         -> False
605

606 607 608
    case m_tc_result of
         Just tc_result
          | not always_do_basic_recompilation_check ->
609
             return $ Right (FrontendTypecheck tc_result, Nothing)
610 611 612
         _ -> do
            (recomp_reqd, mb_checked_iface)
                <- {-# SCC "checkOldIface" #-}
613
                   liftIO $ checkOldIface hsc_env mod_summary
614 615 616 617 618 619 620 621
                                source_modified mb_old_iface
            -- save the interface that comes back from checkOldIface.
            -- In one-shot mode we don't have the old iface until this
            -- point, when checkOldIface reads it from the disk.
            let mb_old_hash = fmap mi_iface_hash mb_checked_iface

            case mb_checked_iface of
                Just iface | not (recompileRequired recomp_reqd) ->
Simon Marlow's avatar
Simon Marlow committed
622 623 624 625 626 627 628 629 630 631 632 633 634
                    -- If the module used TH splices when it was last
                    -- compiled, then the recompilation check is not
                    -- accurate enough (#481) and we must ignore
                    -- it.  However, if the module is stable (none of
                    -- the modules it depends on, directly or
                    -- indirectly, changed), then we *can* skip
                    -- recompilation. This is why the SourceModified
                    -- type contains SourceUnmodifiedAndStable, and
                    -- it's pretty important: otherwise ghc --make
                    -- would always recompile TH modules, even if
                    -- nothing at all has changed. Stability is just
                    -- the same check that make is doing for us in
                    -- one-shot mode.
635 636 637 638 639 640 641 642 643 644
                    case m_tc_result of
                    Nothing
                     | mi_used_th iface && not stable ->
                        compile mb_old_hash (RecompBecause "TH")
                    _ ->
                        skip iface
                _ ->
                    case m_tc_result of
                    Nothing -> compile mb_old_hash recomp_reqd
                    Just tc_result ->
645
                        return $ Right (FrontendTypecheck tc_result, mb_old_hash)
646

647
genericHscFrontend :: ModSummary -> Hsc FrontendResult
648 649 650
genericHscFrontend mod_summary =
  getHooked hscFrontendHook genericHscFrontend' >>= ($ mod_summary)

651 652 653
genericHscFrontend' :: ModSummary -> Hsc FrontendResult
genericHscFrontend' mod_summary
    = FrontendTypecheck `fmap` hscFileFrontEnd mod_summary
654

655 656 657 658
--------------------------------------------------------------
-- Compilers
--------------------------------------------------------------

Austin Seipp's avatar
Austin Seipp committed
659
-- Compile Haskell/boot in OneShot mode.
660 661 662 663 664 665 666 667 668 669 670 671 672
hscIncrementalCompile :: Bool
                      -> Maybe TcGblEnv
                      -> Maybe Messager
                      -> HscEnv
                      -> ModSummary
                      -> SourceModified
                      -> Maybe ModIface
                      -> (Int,Int)
                      -- HomeModInfo does not contain linkable, since we haven't
                      -- code-genned yet
                      -> IO (HscStatus, HomeModInfo)
hscIncrementalCompile always_do_basic_recompilation_check m_tc_result
    mHscMessage hsc_env' mod_summary source_modified mb_old_iface mod_index
673
  = do
dterei's avatar
dterei committed
674 675
    -- One-shot mode needs a knot-tying mutable variable for interface
    -- files. See TcRnTypes.TcGblEnv.tcg_type_env_var.
676
    -- See also Note [hsc_type_env_var hack]
dterei's avatar
dterei committed
677 678
    type_env_var <- newIORef emptyNameEnv
    let mod = ms_mod mod_summary
679 680 681 682
        hsc_env | isOneShot (ghcMode (hsc_dflags hsc_env'))
                = hsc_env' { hsc_type_env_var = Just (mod, type_env_var) }
                | otherwise
                = hsc_env'
683

684 685 686 687 688 689 690 691
    -- NB: enter Hsc monad here so that we don't bail out early with
    -- -Werror on typechecker warnings; we also want to run the desugarer
    -- to get those warnings too. (But we'll always exit at that point
    -- because the desugarer runs ioMsgMaybe.)
    runHsc hsc_env $ do
    e <- hscIncrementalFrontend always_do_basic_recompilation_check m_tc_result mHscMessage
            mod_summary source_modified mb_old_iface mod_index
    case e of
692 693
        -- We didn't need to do any typechecking; the old interface
        -- file on disk was good enough.
694
        Left iface -> do
695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715
            -- Knot tying!  See Note [Knot-tying typecheckIface]
            hmi <- liftIO . fixIO $ \hmi' -> do
                let hsc_env' =
                        hsc_env {
                            hsc_HPT = addToHpt (hsc_HPT hsc_env)
                                        (ms_mod_name mod_summary) hmi'
                        }
                -- NB: This result is actually not that useful
                -- in one-shot mode, since we're not going to do
                -- any further typechecking.  It's much more useful
                -- in make mode, since this HMI will go into the HPT.
                details <- genModDetails hsc_env' iface
                return HomeModInfo{
                    hm_details = details,
                    hm_iface = iface,
                    hm_linkable = Nothing }
            return (HscUpToDate, hmi)
        -- We finished type checking.  (mb_old_hash is the hash of
        -- the interface that existed on disk; it's possible we had
        -- to retypecheck but the resulting interface is exactly
        -- the same.)
716
        Right (FrontendTypecheck tc_result, mb_old_hash) ->
717
            finish mod_summary tc_result mb_old_hash
718 719 720 721 722

-- Runs the post-typechecking frontend (desugar and simplify),
-- and then generates and writes out the final interface. We want
-- to write the interface AFTER simplification so we can get
-- as up-to-date and good unfoldings and other info as possible
723
-- in the interface file.
724
finish :: ModSummary
725 726
       -> TcGblEnv
       -> Maybe Fingerprint
727
       -> Hsc (HscStatus, HomeModInfo)
728 729
finish summary tc_result mb_old_hash = do
  hsc_env <- getHscEnv
730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757
  let dflags = hsc_dflags hsc_env
      target = hscTarget dflags
      hsc_src = ms_hsc_src summary
      should_desugar =
        ms_mod summary /= gHC_PRIM && hsc_src == HsSrcFile
      mk_simple_iface = do
        let hsc_status =
              case (target, hsc_src) of
                (HscNothing, _) -> HscNotGeneratingCode
                (_, HsBootFile) -> HscUpdateBoot
                (_, HsigFile) -> HscUpdateSig
                _ -> panic "finish"
        (iface, changed, details) <- liftIO $
          hscSimpleIface hsc_env tc_result mb_old_hash
        return (iface, changed, details, hsc_status)
  (iface, changed, details, hsc_status) <-
    -- we usually desugar even when we are not generating code, otherwise
    -- we would miss errors thrown by the desugaring (see #10600). The only
    -- exceptions are when the Module is Ghc.Prim or when
    -- it is not a HsSrcFile Module.
    if should_desugar
      then do
        desugared_guts0 <- hscDesugar' (ms_location summary) tc_result
        if target == HscNothing
          -- We are not generating code, so we can skip simplification
          -- and generate a simple interface.
          then mk_simple_iface
          else do
758 759
            plugins <- liftIO $ readIORef (tcg_th_coreplugins tc_result)
            desugared_guts <- hscSimplify' plugins desugared_guts0
760 761 762 763 764 765 766 767 768
            (iface, changed, details, cgguts) <-
              liftIO $ hscNormalIface hsc_env desugared_guts mb_old_hash
            return (iface, changed, details, HscRecomp cgguts summary)
      else mk_simple_iface
  liftIO $ hscMaybeWriteIface dflags iface changed summary
  return
    ( hsc_status
    , HomeModInfo
      {hm_details = details, hm_iface = iface, hm_linkable = Nothing})
769 770 771 772 773 774 775 776 777 778

hscMaybeWriteIface :: DynFlags -> ModIface -> Bool -> ModSummary -> IO ()
hscMaybeWriteIface dflags iface changed summary =
    let force_write_interface = gopt Opt_WriteInterface dflags
        write_interface = case hscTarget dflags of
                            HscNothing      -> False
                            HscInterpreted  -> False
                            _               -> True
    in when (write_interface || force_write_interface) $
            hscWriteIface dflags iface changed summary
779

780 781 782 783
--------------------------------------------------------------
-- NoRecomp handlers
--------------------------------------------------------------

784
-- NB: this must be knot-tied appropriately, see hscIncrementalCompile
785 786
genModDetails :: HscEnv -> ModIface -> IO ModDetails
genModDetails hsc_env old_iface
787
  = do
dterei's avatar
dterei committed
788
    new_details <- {-# SCC "tcRnIface" #-}
789
                   initIfaceLoad hsc_env (typecheckIface old_iface)
790
    dumpIfaceStats hsc_env
dterei's avatar
dterei committed
791
    return new_details
792

793 794 795 796
--------------------------------------------------------------
-- Progress displayers.
--------------------------------------------------------------

797 798
oneShotMsg :: HscEnv -> RecompileRequired -> IO ()
oneShotMsg hsc_env recomp =
dterei's avatar
dterei committed
799
    case recomp of
800
        UpToDate ->
801 802
            compilationProgressMsg (hsc_dflags hsc_env) $
                   "compilation IS NOT required"
803
        _ ->
804 805
            return ()

806 807
batchMsg :: Messager
batchMsg hsc_env mod_index recomp mod_summary =
dterei's avatar
dterei committed
808
    case recomp of
809 810 811
        MustCompile -> showMsg "Compiling " ""
        UpToDate
            | verbosity (hsc_dflags hsc_env) >= 2 -> showMsg "Skipping  " ""
dterei's avatar
dterei committed
812
            | otherwise -> return ()
813
        RecompBecause reason -> showMsg "Compiling " (" [" ++ reason ++ "]")
dterei's avatar
dterei committed
814
    where
Ian Lynagh's avatar
Ian Lynagh committed
815
        dflags = hsc_dflags hsc_env
816
        showMsg msg reason =
Ian Lynagh's avatar
Ian Lynagh committed
817
            compilationProgressMsg dflags $
818
            (showModuleIndex mod_index ++
Ian Lynagh's avatar
Ian Lynagh committed
819
            msg ++ showModMsg dflags (hscTarget dflags)
820 821
                              (recompileRequired recomp) mod_summary)
                ++ reason
822

823 824 825
--------------------------------------------------------------
-- FrontEnds
--------------------------------------------------------------
826

827 828
-- | Given a 'ModSummary', parses and typechecks it, returning the
-- 'TcGblEnv' resulting from type-checking.
829
hscFileFrontEnd :: ModSummary -> Hsc TcGblEnv
Edward Z. Yang's avatar
Edward Z. Yang committed
830
hscFileFrontEnd mod_summary = hscTypecheck False mod_summary Nothing
831 832

--------------------------------------------------------------
833
-- Safe Haskell
834 835
--------------------------------------------------------------

836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855
-- Note [Safe Haskell Trust Check]
-- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-- Safe Haskell checks that an import is trusted according to the following
-- rules for an import of module M that resides in Package P:
--
--   * If M is recorded as Safe and all its trust dependencies are OK
--     then M is considered safe.
--   * If M is recorded as Trustworthy and P is considered trusted and
--     all M's trust dependencies are OK then M is considered safe.
--
-- By trust dependencies we mean that the check is transitive. So if
-- a module M that is Safe relies on a module N that is trustworthy,
-- importing module M will first check (according to the second case)
-- that N is trusted before checking M is trusted.
--
-- This is a minimal description, so please refer to the user guide
-- for more details. The user guide is also considered the authoritative
-- source in this matter, not the comments or code.


856 857 858
-- Note [Safe Haskell Inference]
-- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-- Safe Haskell does Safe inference on modules that don't have any specific
Gabor Greif's avatar
Gabor Greif committed
859
-- safe haskell mode flag. The basic approach to this is:
860 861 862 863 864 865 866
--   * When deciding if we need to do a Safe language check, treat
--     an unmarked module as having -XSafe mode specified.
--   * For checks, don't throw errors but return them to the caller.
--   * Caller checks if there are errors:
--     * For modules explicitly marked -XSafe, we throw the errors.
--     * For unmarked modules (inference mode), we drop the errors
--       and mark the module as being Unsafe.
867 868 869
--
-- It used to be that we only did safe inference on modules that had no Safe
-- Haskell flags, but now we perform safe inference on all modules as we want
870 871
-- to allow users to set the `-Wsafe`, `-Wunsafe` and
-- `-Wtrustworthy-safe` flags on Trustworthy and Unsafe modules so that a
872 873 874 875 876 877 878
-- user can ensure their assumptions are correct and see reasons for why a
-- module is safe or unsafe.
--
-- This is tricky as we must be careful when we should throw an error compared
-- to just warnings. For checking safe imports we manage it as two steps. First
-- we check any imports that are required to be safe, then we check all other
-- imports to see if we can infer them to be safe.
879 880 881 882 883 884 885 886 887


-- | Check that the safe imports of the module being compiled are valid.
-- If not we either issue a compilation error if the module is explicitly
-- using Safe Haskell, or mark the module as unsafe if we're in safe
-- inference mode.
hscCheckSafeImports :: TcGblEnv -> Hsc TcGblEnv
hscCheckSafeImports tcg_env = do
    dflags   <- getDynFlags
888
    tcg_env' <- checkSafeImports tcg_env
889
    checkRULES dflags tcg_env'
890

dterei's avatar
dterei committed
891
  where
892 893 894 895 896 897 898 899 900 901 902 903 904 905 906
    checkRULES dflags tcg_env' = do
      case safeLanguageOn dflags of
          True -> do
              -- XSafe: we nuke user written RULES
              logWarnings $ warns dflags (tcg_rules tcg_env')
              return tcg_env' { tcg_rules = [] }
          False
                -- SafeInferred: user defined RULES, so not safe
              | safeInferOn dflags && not (null $ tcg_rules tcg_env')
              -> markUnsafeInfer tcg_env' $ warns dflags (tcg_rules tcg_env')

                -- Trustworthy OR SafeInferred: with no RULES
              | otherwise
              -> return tcg_env'

Ian Lynagh's avatar
Ian Lynagh committed
907 908 909
    warns dflags rules = listToBag $ map (warnRules dflags) rules
    warnRules dflags (L loc (HsRule n _ _ _ _ _ _)) =
        mkPlainWarnMsg dflags loc $
910
            text "Rule \"" <> ftext (snd $ unLoc n) <> text "\" ignored" $+$
dterei's avatar
dterei committed
911
            text "User defined rules are disabled under Safe Haskell"
912

913 914 915 916 917 918
-- | Validate that safe imported modules are actually safe.  For modules in the
-- HomePackage (the package the module we are compiling in resides) this just
-- involves checking its trust type is 'Safe' or 'Trustworthy'. For modules
-- that reside in another package we also must check that the external pacakge
-- is trusted. See the Note [Safe Haskell Trust Check] above for more
-- information.
919
--
920 921 922 923 924
-- The code for this is quite tricky as the whole algorithm is done in a few
-- distinct phases in different parts of the code base. See
-- RnNames.rnImportDecl for where package trust dependencies for a module are
-- collected and unioned.  Specifically s