HscMain.hs 68.9 KB
Newer Older
1 2
{-# LANGUAGE BangPatterns, CPP, MagicHash, NondecreasingIndentation #-}

dterei's avatar
dterei committed
3 4
-------------------------------------------------------------------------------
--
5
-- | Main API for compiling plain Haskell source code.
6
--
dterei's avatar
dterei committed
7
-- This module implements compilation of a Haskell source. It is
8 9 10 11 12
-- /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
13
-- "interactive" mode (GHCi). There are also entry points for
14 15 16 17 18 19 20 21
-- 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).
--
22 23 24 25 26
-- 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.
27
--
dterei's avatar
dterei committed
28 29 30 31
-- (c) The GRASP/AQUA Project, Glasgow University, 1993-2000
--
-------------------------------------------------------------------------------

32
module HscMain
dterei's avatar
dterei committed
33
    (
34 35 36 37
    -- * Making an HscEnv
      newHscEnv

    -- * Compiling complete source files
38 39
    , Messager, batchMsg
    , HscStatus (..)
40
    , hscIncrementalCompile
41 42
    , hscCompileCmmFile

43 44 45
    , hscGenHardCode
    , hscInteractive

46
    -- * Running passes separately
Thomas Schilling's avatar
Thomas Schilling committed
47 48 49
    , hscParse
    , hscTypecheckRename
    , hscDesugar
Simon Marlow's avatar
Simon Marlow committed
50
    , makeSimpleDetails
51 52
    , hscSimplify -- ToDo, shouldn't really export this

53 54 55 56
    -- * Safe Haskell
    , hscCheckSafe
    , hscGetSafe

57 58 59 60 61
    -- * Support for interactive evaluation
    , hscParseIdentifier
    , hscTcRcLookupName
    , hscTcRnGetInfo
#ifdef GHCI
dterei's avatar
dterei committed
62
    , hscIsGHCiMonad
63
    , hscGetModuleInterface
64
    , hscRnImportDecls
65
    , hscTcRnLookupRdrName
66
    , hscStmt, hscStmtWithLocation, hscParsedStmt
67
    , hscDecls, hscDeclsWithLocation
vivian's avatar
vivian committed
68
    , hscTcExpr, hscImport, hscKcType
69
    , hscParseExpr
70
    , hscCompileCoreExpr
71 72
    -- * Low-level exports for hooks
    , hscCompileCoreExpr'
73
#endif
Edsko de Vries's avatar
Edsko de Vries committed
74 75
      -- We want to make sure that we export enough to be able to redefine
      -- hscFileFrontEnd in client code
76
    , hscParse', hscSimplify', hscDesugar', tcRnModule'
Edsko de Vries's avatar
Edsko de Vries committed
77
    , getHscEnv
78 79 80
    , hscSimpleIface', hscNormalIface'
    , oneShotMsg
    , hscFileFrontEnd, genericHscFrontend, dumpIfaceStats
81
    ) where
82

83
#ifdef GHCI
Simon Marlow's avatar
Simon Marlow committed
84
import Id
85
import GHCi.RemoteTypes ( ForeignHValue )
86
import ByteCodeGen      ( byteCodeGen, coreExprToBCOs )
87
import Linker
88
import CoreTidy         ( tidyExpr )
89 90
import Type             ( Type )
import {- Kind parts of -} Type         ( Kind )
91
import CoreLint         ( lintInteractiveExpr )
92
import VarEnv           ( emptyTidyEnv )
93
import THNames          ( templateHaskellNames )
94
import Panic
95
import ConLike
96
import Control.Concurrent
97 98
#endif

99 100
import Module
import Packages
Simon Marlow's avatar
Simon Marlow committed
101 102
import RdrName
import HsSyn
103
import CoreSyn
Ian Lynagh's avatar
Ian Lynagh committed
104
import StringBuffer
105
import Parser
106
import Lexer
107 108
import SrcLoc
import TcRnDriver
109
import TcIface          ( typecheckIface )
110
import TcRnMonad
111
import IfaceEnv         ( initNameCache )
112
import LoadIface        ( ifaceStats, initExternalPackageState )
113
import PrelInfo
Simon Marlow's avatar
Simon Marlow committed
114
import MkIface
115 116
import Desugar
import SimplCore
Simon Marlow's avatar
Simon Marlow committed
117
import TidyPgm
118
import CorePrep
119 120
import CoreToStg        ( coreToStg )
import qualified StgCmm ( codeGen )
121 122
import StgSyn
import CostCentre
123
import ProfInit
124 125
import TyCon
import Name
126
import SimplStg         ( stg2stg )
127
import Cmm
128
import CmmParse         ( parseCmmFile )
129
import CmmBuildInfoTables
Edward Z. Yang's avatar
Edward Z. Yang committed
130
import CmmPipeline
131
import CmmInfo
132
import CodeOutput
133
import NameEnv          ( emptyNameEnv )
134
import InstEnv
135
import FamInstEnv
Thomas Schilling's avatar
Thomas Schilling committed
136
import Fingerprint      ( Fingerprint )
137
import Hooks
138
import Maybes
139

140
import DynFlags
141
import ErrUtils
142

143
import Outputable
eir@cis.upenn.edu's avatar
eir@cis.upenn.edu committed
144 145
import UniqFM
import NameEnv
146
import HscStats         ( ppSourceStats )
147
import HscTypes
148
import FastString
149
import UniqSupply
150
import Bag
Thomas Schilling's avatar
Thomas Schilling committed
151
import Exception
152 153 154
import qualified Stream
import Stream (Stream)

155
import Util
Simon Marlow's avatar
Simon Marlow committed
156

157
import Data.List
Simon Marlow's avatar
Simon Marlow committed
158 159
import Control.Monad
import Data.IORef
160
import System.FilePath as FilePath
161
import System.Directory
Alan Zimmerman's avatar
Alan Zimmerman committed
162
import qualified Data.Map as Map
dterei's avatar
dterei committed
163

Thomas Schilling's avatar
Thomas Schilling committed
164
#include "HsVersions.h"
165

166

dterei's avatar
dterei committed
167 168 169 170 171
{- **********************************************************************
%*                                                                      *
                Initialisation
%*                                                                      *
%********************************************************************* -}
172

173
newHscEnv :: DynFlags -> IO HscEnv
174
newHscEnv dflags = do
dterei's avatar
dterei committed
175 176
    eps_var <- newIORef initExternalPackageState
    us      <- mkSplitUniqSupply 'r'
177
    nc_var  <- newIORef (initNameCache us allKnownKeyNames)
178
    fc_var  <- newIORef emptyModuleEnv
179
#ifdef GHCI
180
    iserv_mvar <- newMVar Nothing
181
#endif
182 183 184 185 186 187 188 189 190 191 192 193 194
    return HscEnv {  hsc_dflags       = dflags
                  ,  hsc_targets      = []
                  ,  hsc_mod_graph    = []
                  ,  hsc_IC           = emptyInteractiveContext dflags
                  ,  hsc_HPT          = emptyHomePackageTable
                  ,  hsc_EPS          = eps_var
                  ,  hsc_NC           = nc_var
                  ,  hsc_FC           = fc_var
                  ,  hsc_type_env_var = Nothing
#ifdef GHCI
                  , hsc_iserv        = iserv_mvar
#endif
                  }
Thomas Schilling's avatar
Thomas Schilling committed
195

196

197
allKnownKeyNames :: [Name]      -- Put here to avoid loops involving DsMeta,
eir@cis.upenn.edu's avatar
eir@cis.upenn.edu committed
198 199 200 201 202 203 204 205 206 207 208 209 210
allKnownKeyNames                -- where templateHaskellNames are defined
  | debugIsOn
  , not (isNullUFM badNamesEnv)
  = panic ("badAllKnownKeyNames:\n" ++ badNamesStr)
       -- NB: We can't use ppr here, because this is sometimes evaluated in a
       -- context where there are no DynFlags available, leading to a cryptic
       -- "<<details unavailable>>" error. (This seems to happen only in the
       -- stage 2 compiler, for reasons I [Richard] have no clue of.)

  | otherwise
  = all_names
  where
    all_names = knownKeyNames
211
#ifdef GHCI
eir@cis.upenn.edu's avatar
eir@cis.upenn.edu committed
212
                ++ templateHaskellNames
213 214
#endif

eir@cis.upenn.edu's avatar
eir@cis.upenn.edu committed
215 216 217 218 219 220 221 222 223 224 225 226 227 228
    namesEnv      = foldl (\m n -> extendNameEnv_Acc (:) singleton m n n)
                          emptyUFM all_names
    badNamesEnv   = filterNameEnv (\ns -> length ns > 1) namesEnv
    badNamesPairs = nameEnvUniqueElts badNamesEnv
    badNamesStrs  = map pairToStr badNamesPairs
    badNamesStr   = unlines badNamesStrs

    pairToStr (uniq, ns) = "        " ++
                           show uniq ++
                           ": [" ++
                           intercalate ", " (map (occNameString . nameOccName) ns) ++
                           "]"


229
-- -----------------------------------------------------------------------------
230

231
getWarnings :: Hsc WarningMessages
dterei's avatar
dterei committed
232
getWarnings = Hsc $ \_ w -> return (w, w)
233 234

clearWarnings :: Hsc ()
dterei's avatar
dterei committed
235
clearWarnings = Hsc $ \_ _ -> return ((), emptyBag)
236 237

logWarnings :: WarningMessages -> Hsc ()
dterei's avatar
dterei committed
238
logWarnings w = Hsc $ \_ w0 -> return ((), w0 `unionBags` w)
239 240

getHscEnv :: Hsc HscEnv
dterei's avatar
dterei committed
241
getHscEnv = Hsc $ \e w -> return (e, w)
242 243 244

handleWarnings :: Hsc ()
handleWarnings = do
dterei's avatar
dterei committed
245 246 247 248
    dflags <- getDynFlags
    w <- getWarnings
    liftIO $ printOrThrowWarnings dflags w
    clearWarnings
249 250 251 252 253

-- | 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
254 255
    logWarnings warns
    when (not $ isEmptyBag errs) $ throwErrors errs
256 257 258 259

-- | Throw some errors.
throwErrors :: ErrorMessages -> Hsc a
throwErrors = liftIO . throwIO . mkSrcErr
260 261 262 263 264

-- | 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
265
-- and signal success via by wrapping the result in a 'Maybe' type. This
266 267 268 269 270 271 272 273 274
-- 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
275
--     there should be warnings in the first result. That is, if the action
276 277 278
--     failed, it must have been due to the warnings (i.e., @-Werror@).
ioMsgMaybe :: IO (Messages, Maybe a) -> Hsc a
ioMsgMaybe ioA = do
279
    ((warns,errs), mb_r) <- liftIO ioA
dterei's avatar
dterei committed
280 281 282 283
    logWarnings warns
    case mb_r of
        Nothing -> throwErrors errs
        Just r  -> ASSERT( isEmptyBag errs ) return r
284 285 286 287 288

-- | 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
289 290 291
    ((warns,_errs), mb_r) <- liftIO $ ioA
    logWarnings warns
    return mb_r
292 293 294 295 296

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

#ifdef GHCI
297
hscTcRnLookupRdrName :: HscEnv -> Located RdrName -> IO [Name]
298 299
hscTcRnLookupRdrName hsc_env0 rdr_name
  = runInteractiveHsc hsc_env0 $
300 301
    do { hsc_env <- getHscEnv
       ; ioMsgMaybe $ tcRnLookupRdrName hsc_env rdr_name }
302 303 304
#endif

hscTcRcLookupName :: HscEnv -> Name -> IO (Maybe TyThing)
305 306 307
hscTcRcLookupName hsc_env0 name = runInteractiveHsc hsc_env0 $ do
  hsc_env <- getHscEnv
  ioMsgMaybe' $ tcRnLookupName hsc_env name
dterei's avatar
dterei committed
308 309 310
      -- 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.
311

312
hscTcRnGetInfo :: HscEnv -> Name -> IO (Maybe (TyThing, Fixity, [ClsInst], [FamInst]))
313 314 315 316
hscTcRnGetInfo hsc_env0 name
  = runInteractiveHsc hsc_env0 $
    do { hsc_env <- getHscEnv
       ; ioMsgMaybe' $ tcRnGetInfo hsc_env name }
317 318

#ifdef GHCI
dterei's avatar
dterei committed
319
hscIsGHCiMonad :: HscEnv -> String -> IO Name
Edsko de Vries's avatar
Edsko de Vries committed
320
hscIsGHCiMonad hsc_env name
321
  = runHsc hsc_env $ ioMsgMaybe $ isGHCiMonad hsc_env name
dterei's avatar
dterei committed
322

323
hscGetModuleInterface :: HscEnv -> Module -> IO ModIface
324 325 326
hscGetModuleInterface hsc_env0 mod = runInteractiveHsc hsc_env0 $ do
  hsc_env <- getHscEnv
  ioMsgMaybe $ getModuleInterface hsc_env mod
327 328 329

-- -----------------------------------------------------------------------------
-- | Rename some import declarations
330
hscRnImportDecls :: HscEnv -> [LImportDecl RdrName] -> IO GlobalRdrEnv
331 332 333
hscRnImportDecls hsc_env0 import_decls = runInteractiveHsc hsc_env0 $ do
  hsc_env <- getHscEnv
  ioMsgMaybe $ tcRnImportDecls hsc_env import_decls
334 335
#endif

336
-- -----------------------------------------------------------------------------
Simon Marlow's avatar
Simon Marlow committed
337
-- | parse a file, returning the abstract syntax
338

339
hscParse :: HscEnv -> ModSummary -> IO HsParsedModule
340 341 342
hscParse hsc_env mod_summary = runHsc hsc_env $ hscParse' mod_summary

-- internal version, that doesn't fail due to -Werror
343
hscParse' :: ModSummary -> Hsc HsParsedModule
344
hscParse' mod_summary = do
dterei's avatar
dterei committed
345 346 347
    dflags <- getDynFlags
    let src_filename  = ms_hspp_file mod_summary
        maybe_src_buf = ms_hspp_buf  mod_summary
348

dterei's avatar
dterei committed
349 350 351
    --------------------------  Parser  ----------------
    liftIO $ showPass dflags "Parser"
    {-# SCC "Parser" #-} do
352 353 354 355

    -- 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
356 357 358
    buf <- case maybe_src_buf of
               Just b  -> return b
               Nothing -> liftIO $ hGetStringBuffer src_filename
359

dterei's avatar
dterei committed
360
    let loc = mkRealSrcLoc (mkFastString src_filename) 1 1
361

dterei's avatar
dterei committed
362 363
    case unP parseModule (mkPState dflags buf loc) of
        PFailed span err ->
Ian Lynagh's avatar
Ian Lynagh committed
364
            liftIO $ throwOneError (mkPlainErrMsg dflags span err)
365

dterei's avatar
dterei committed
366 367 368 369 370 371
        POk pst rdr_module -> do
            logWarningsReportErrors (getMessages pst)
            liftIO $ dumpIfSet_dyn dflags Opt_D_dump_parsed "Parser" $
                                   ppr rdr_module
            liftIO $ dumpIfSet_dyn dflags Opt_D_source_stats "Source Statistics" $
                                   ppSourceStats False rdr_module
372 373 374 375 376 377 378 379 380 381 382 383 384 385 386

            -- 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>"
            --   - normalise them (elimiante differences between ./f and f)
            --   - 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
387
                            $ filter (not . (isPrefixOf "<"))
388 389 390 391 392 393
                            $ map unpackFS
                            $ srcfiles pst
                srcs1 = case ml_hs_file (ms_location mod_summary) of
                          Just f  -> filter (/= FilePath.normalise f) srcs0
                          Nothing -> srcs0

394 395 396 397 398
            -- sometimes we see source files from earlier
            -- preprocessing stages that cannot be found, so just
            -- filter them out:
            srcs2 <- liftIO $ filterM doesFileExist srcs1

399 400
            return HsParsedModule {
                      hpm_module    = rdr_module,
Alan Zimmerman's avatar
Alan Zimmerman committed
401 402 403 404 405
                      hpm_src_files = srcs2,
                      hpm_annotations
                              = (Map.fromListWith (++) $ annotations pst,
                                 Map.fromList $ ((noSrcSpan,comment_q pst)
                                                 :(annotations_comments pst)))
406
                   }
Simon Marlow's avatar
Simon Marlow committed
407

Thomas Schilling's avatar
Thomas Schilling committed
408 409 410
-- 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
411
type RenamedStuff =
Simon Marlow's avatar
Simon Marlow committed
412
        (Maybe (HsGroup Name, [LImportDecl Name], Maybe [LIE Name],
413
                Maybe LHsDocString))
Simon Marlow's avatar
Simon Marlow committed
414

Thomas Schilling's avatar
Thomas Schilling committed
415
-- | Rename and typecheck a module, additionally returning the renamed syntax
416
hscTypecheckRename :: HscEnv -> ModSummary -> HsParsedModule
417
                   -> IO (TcGblEnv, RenamedStuff)
dterei's avatar
dterei committed
418
hscTypecheckRename hsc_env mod_summary rdr_module = runHsc hsc_env $ do
419
    tc_result <- tcRnModule' hsc_env mod_summary True rdr_module
Thomas Schilling's avatar
Thomas Schilling committed
420

421 422 423 424 425 426
        -- This 'do' is in the Maybe monad!
    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
427

428
    return (tc_result, rn_info)
Simon Marlow's avatar
Simon Marlow committed
429

430 431 432 433 434 435 436 437
-- wrapper around tcRnModule to handle safe haskell extras
tcRnModule' :: HscEnv -> ModSummary -> Bool -> HsParsedModule
            -> Hsc TcGblEnv
tcRnModule' hsc_env sum save_rn_syntax mod = do
    tcg_res <- {-# SCC "Typecheck-Rename" #-}
               ioMsgMaybe $
                   tcRnModule hsc_env (ms_hsc_src sum) save_rn_syntax mod

438 439 440
    -- 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)
441
    dflags   <- getDynFlags
442
    let allSafeOK = safeInferred dflags && tcSafeOK
443

444 445 446
    -- 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
447
        then markUnsafeInfer tcg_res whyUnsafe
448

449
        -- module (could be) safe, throw warning if needed
450 451
        else do
            tcg_res' <- hscCheckSafeImports tcg_res
452
            safe <- liftIO $ fst <$> readIORef (tcg_safeInfer tcg_res')
453 454 455 456 457 458 459 460 461
            when safe $ do
              case wopt Opt_WarnSafe dflags of
                True -> (logWarnings $ unitBag $ mkPlainWarnMsg dflags
                       (warnSafeOnLoc dflags) $ errSafe tcg_res')
                False | safeHaskell dflags == Sf_Trustworthy &&
                        wopt Opt_WarnTrustworthySafe dflags ->
                  (logWarnings $ unitBag $ mkPlainWarnMsg dflags
                    (trustworthyOnLoc dflags) $ errTwthySafe tcg_res')
                False -> return ()
462 463 464
            return tcg_res'
  where
    pprMod t  = ppr $ moduleName $ tcg_mod t
465
    errSafe t = quotes (pprMod t) <+> text "has been inferred as safe!"
466 467
    errTwthySafe t = quotes (pprMod t)
      <+> text "is marked as Trustworthy but has been inferred as safe!"
468

Simon Marlow's avatar
Simon Marlow committed
469
-- | Convert a typechecked module to Core
470
hscDesugar :: HscEnv -> ModSummary -> TcGblEnv -> IO ModGuts
471
hscDesugar hsc_env mod_summary tc_result =
Ian Lynagh's avatar
Ian Lynagh committed
472
    runHsc hsc_env $ hscDesugar' (ms_location mod_summary) tc_result
473

Ian Lynagh's avatar
Ian Lynagh committed
474 475
hscDesugar' :: ModLocation -> TcGblEnv -> Hsc ModGuts
hscDesugar' mod_location tc_result = do
dterei's avatar
dterei committed
476
    hsc_env <- getHscEnv
Simon Marlow's avatar
Simon Marlow committed
477 478
    r <- ioMsgMaybe $
      {-# SCC "deSugar" #-}
Ian Lynagh's avatar
Ian Lynagh committed
479
      deSugar hsc_env mod_location tc_result
480

dterei's avatar
dterei committed
481 482 483 484
    -- 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
485

dterei's avatar
dterei committed
486
-- | Make a 'ModDetails' from the results of typechecking. Used when
Simon Marlow's avatar
Simon Marlow committed
487
-- typechecking only, as opposed to full compilation.
488 489
makeSimpleDetails :: HscEnv -> TcGblEnv -> IO ModDetails
makeSimpleDetails hsc_env tc_result = mkBootModDetailsTc hsc_env tc_result
Simon Marlow's avatar
Simon Marlow committed
490

491

dterei's avatar
dterei committed
492 493 494 495 496 497 498
{- **********************************************************************
%*                                                                      *
                The main compiler pipeline
%*                                                                      *
%********************************************************************* -}

{-
499 500 501 502
                   --------------------------------
                        The compilation proper
                   --------------------------------

dterei's avatar
dterei committed
503 504 505 506 507 508
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
509
targets byte-code.
dterei's avatar
dterei committed
510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534

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.
-}


535 536
type Messager = HscEnv -> (Int,Int) -> RecompileRequired -> ModSummary -> IO ()

537 538 539 540 541 542 543 544 545 546 547 548 549 550 551
-- | 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
552
  always_do_basic_recompilation_check m_tc_result
553
  mHscMessage mod_summary source_modified mb_old_iface mod_index
554
    = do
555
    hsc_env <- getHscEnv
556 557 558 559

    let msg what = case mHscMessage of
                   Just hscMessage -> hscMessage hsc_env mod_index what mod_summary
                   Nothing -> return ()
dterei's avatar
dterei committed
560

561
        skip iface = do
562
            liftIO $ msg UpToDate
563
            return $ Left iface
dterei's avatar
dterei committed
564

565
        compile mb_old_hash reason = do
566 567 568
            liftIO $ msg reason
            result <- genericHscFrontend mod_summary
            return $ Right (result, mb_old_hash)
dterei's avatar
dterei committed
569 570 571 572

        stable = case source_modified of
                     SourceUnmodifiedAndStable -> True
                     _                         -> False
573

574 575 576
    case m_tc_result of
         Just tc_result
          | not always_do_basic_recompilation_check ->
577
             return $ Right (FrontendTypecheck tc_result, Nothing)
578 579 580
         _ -> do
            (recomp_reqd, mb_checked_iface)
                <- {-# SCC "checkOldIface" #-}
581
                   liftIO $ checkOldIface hsc_env mod_summary
582 583 584 585 586 587 588 589
                                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
590 591 592 593 594 595 596 597 598 599 600 601 602
                    -- 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.
603 604 605 606 607 608 609 610 611 612
                    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 ->
613
                        return $ Right (FrontendTypecheck tc_result, mb_old_hash)
614

615
genericHscFrontend :: ModSummary -> Hsc FrontendResult
616 617 618
genericHscFrontend mod_summary =
  getHooked hscFrontendHook genericHscFrontend' >>= ($ mod_summary)

619 620 621
genericHscFrontend' :: ModSummary -> Hsc FrontendResult
genericHscFrontend' mod_summary
    = FrontendTypecheck `fmap` hscFileFrontEnd mod_summary
622

623 624 625 626
--------------------------------------------------------------
-- Compilers
--------------------------------------------------------------

Austin Seipp's avatar
Austin Seipp committed
627
-- Compile Haskell/boot in OneShot mode.
628 629 630 631 632 633 634 635 636 637 638 639 640
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
641
  = do
dterei's avatar
dterei committed
642 643 644 645
    -- One-shot mode needs a knot-tying mutable variable for interface
    -- files. See TcRnTypes.TcGblEnv.tcg_type_env_var.
    type_env_var <- newIORef emptyNameEnv
    let mod = ms_mod mod_summary
646
        hsc_env = hsc_env'{ hsc_type_env_var = Just (mod, type_env_var) }
647

648 649 650 651 652 653
    -- 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
    let dflags = hsc_dflags hsc_env
654

655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687
    e <- hscIncrementalFrontend always_do_basic_recompilation_check m_tc_result mHscMessage
            mod_summary source_modified mb_old_iface mod_index
    case e of
        Left iface -> do
            details <- liftIO $ genModDetails hsc_env iface
            return (HscUpToDate, HomeModInfo{
                hm_details = details,
                hm_iface = iface,
                hm_linkable = Nothing
            })
        Right (result, mb_old_hash) -> do
            (status, hmi, no_change) <- case result of
                FrontendTypecheck tc_result ->
                    if hscTarget dflags /= HscNothing &&
                       ms_hsc_src mod_summary == HsSrcFile
                       then finish              hsc_env mod_summary tc_result mb_old_hash
                       else finishTypecheckOnly hsc_env mod_summary tc_result mb_old_hash
            liftIO $ hscMaybeWriteIface dflags (hm_iface hmi) no_change mod_summary
            return (status, hmi)

-- Generates and writes out the final interface for a typecheck.
finishTypecheckOnly :: HscEnv
              -> ModSummary
              -> TcGblEnv
              -> Maybe Fingerprint
              -> Hsc (HscStatus, HomeModInfo, Bool)
finishTypecheckOnly hsc_env summary tc_result mb_old_hash = do
    let dflags = hsc_dflags hsc_env
    (iface, changed, details) <- liftIO $ hscSimpleIface hsc_env tc_result mb_old_hash
    let hsc_status =
          case (hscTarget dflags, ms_hsc_src summary) of
            (HscNothing, _) -> HscNotGeneratingCode
            (_, HsBootFile) -> HscUpdateBoot
688
            (_, HsigFile) -> HscUpdateSig
689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729
            _ -> panic "finishTypecheckOnly"
    return (hsc_status,
            HomeModInfo{ hm_details  = details,
                         hm_iface    = iface,
                         hm_linkable = Nothing },
            changed)

-- 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
-- in the interface file.  This is only ever run for HsSrcFile,
-- and NOT for HscNothing.
finish :: HscEnv
       -> ModSummary
       -> TcGblEnv
       -> Maybe Fingerprint
       -> Hsc (HscStatus, HomeModInfo, Bool)
finish hsc_env summary tc_result mb_old_hash = do
    let dflags = hsc_dflags hsc_env
    MASSERT( ms_hsc_src summary == HsSrcFile )
    MASSERT( hscTarget dflags /= HscNothing )
    guts0 <- hscDesugar' (ms_location summary) tc_result
    guts <- hscSimplify' guts0
    (iface, changed, details, cgguts) <- liftIO $ hscNormalIface hsc_env guts mb_old_hash

    return (HscRecomp cgguts summary,
            HomeModInfo{ hm_details  = details,
                         hm_iface    = iface,
                         hm_linkable = Nothing },
            changed)

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
730

731 732 733 734
--------------------------------------------------------------
-- NoRecomp handlers
--------------------------------------------------------------

735 736
genModDetails :: HscEnv -> ModIface -> IO ModDetails
genModDetails hsc_env old_iface
737
  = do
dterei's avatar
dterei committed
738
    new_details <- {-# SCC "tcRnIface" #-}
739 740
                   initIfaceCheck hsc_env (typecheckIface old_iface)
    dumpIfaceStats hsc_env
dterei's avatar
dterei committed
741
    return new_details
742

743 744 745 746
--------------------------------------------------------------
-- Progress displayers.
--------------------------------------------------------------

747 748
oneShotMsg :: HscEnv -> RecompileRequired -> IO ()
oneShotMsg hsc_env recomp =
dterei's avatar
dterei committed
749
    case recomp of
750
        UpToDate ->
751 752
            compilationProgressMsg (hsc_dflags hsc_env) $
                   "compilation IS NOT required"
753
        _ ->
754 755
            return ()

756 757
batchMsg :: Messager
batchMsg hsc_env mod_index recomp mod_summary =
dterei's avatar
dterei committed
758
    case recomp of
759 760 761
        MustCompile -> showMsg "Compiling " ""
        UpToDate
            | verbosity (hsc_dflags hsc_env) >= 2 -> showMsg "Skipping  " ""
dterei's avatar
dterei committed
762
            | otherwise -> return ()
763
        RecompBecause reason -> showMsg "Compiling " (" [" ++ reason ++ "]")
dterei's avatar
dterei committed
764
    where
Ian Lynagh's avatar
Ian Lynagh committed
765
        dflags = hsc_dflags hsc_env
766
        showMsg msg reason =
Ian Lynagh's avatar
Ian Lynagh committed
767
            compilationProgressMsg dflags $
768
            (showModuleIndex mod_index ++
Ian Lynagh's avatar
Ian Lynagh committed
769
            msg ++ showModMsg dflags (hscTarget dflags)
770 771
                              (recompileRequired recomp) mod_summary)
                ++ reason
772

773 774 775
--------------------------------------------------------------
-- FrontEnds
--------------------------------------------------------------
776

777 778
-- | Given a 'ModSummary', parses and typechecks it, returning the
-- 'TcGblEnv' resulting from type-checking.
779
hscFileFrontEnd :: ModSummary -> Hsc TcGblEnv
780
hscFileFrontEnd mod_summary = do
781
    hpm <- hscParse' mod_summary
782
    hsc_env <- getHscEnv
783 784
    tcg_env <- tcRnModule' hsc_env mod_summary False hpm
    return tcg_env
785 786

--------------------------------------------------------------
787
-- Safe Haskell
788 789
--------------------------------------------------------------

790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809
-- 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.


810 811 812
-- Note [Safe Haskell Inference]
-- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-- Safe Haskell does Safe inference on modules that don't have any specific
Gabor Greif's avatar
Gabor Greif committed
813
-- safe haskell mode flag. The basic approach to this is:
814 815 816 817 818 819 820
--   * 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.
821 822 823
--
-- 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
824 825
-- to allow users to set the `-Wsafe`, `-Wunsafe` and
-- `-Wtrustworthy-safe` flags on Trustworthy and Unsafe modules so that a
826 827 828 829 830 831 832
-- 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.
833 834 835 836 837 838 839 840 841


-- | 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
842
    tcg_env' <- checkSafeImports dflags tcg_env
843
    checkRULES dflags tcg_env'
844

dterei's avatar
dterei committed
845
  where
846 847 848 849 850 851 852 853 854 855 856 857 858 859 860
    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
861 862 863
    warns dflags rules = listToBag $ map (warnRules dflags) rules
    warnRules dflags (L loc (HsRule n _ _ _ _ _ _)) =
        mkPlainWarnMsg dflags loc $
864
            text "Rule \"" <> ftext (snd $ unLoc n) <> text "\" ignored" $+$
dterei's avatar
dterei committed
865
            text "User defined rules are disabled under Safe Haskell"
866

867 868 869 870 871 872
-- | 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.
873
--
874 875 876 877 878
-- 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 see the Note [RnNames . Tracking Trust
-- Transitively] and the Note [RnNames . Trust Own Package].
879 880
checkSafeImports :: DynFlags -> TcGblEnv -> Hsc TcGblEnv
checkSafeImports dflags tcg_env
881
    = do
882 883 884
        imps <- mapM condense imports'
        let (safeImps, regImps) = partition (\(_,_,s) -> s) imps

885 886 887 888 889
        -- We want to use the warning state specifically for detecting if safe
        -- inference has failed, so store and clear any existing warnings.
        oldErrs <- getWarnings
        clearWarnings

890 891 892
        -- Check safe imports are correct
        safePkgs <- mapM checkSafe safeImps
        safeErrs <- getWarnings
dterei's avatar
dterei committed
893 894
        clearWarnings

895
        -- Check non-safe imports are correct if inferring safety
896
        -- See the Note [Safe Haskell Inference]
897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919
        (infErrs, infPkgs) <- case (safeInferOn dflags) of
          False -> return (emptyBag, [])
          True -> do infPkgs <- mapM checkSafe regImps
                     infErrs <- getWarnings
                     clearWarnings
                     return (infErrs, infPkgs)

        -- restore old errors
        logWarnings oldErrs

        case (isEmptyBag safeErrs) of
          -- Failed safe check
          False -> liftIO . throwIO . mkSrcErr $ safeErrs

          -- Passed safe check
          True -> do
            let infPassed = isEmptyBag infErrs
            tcg_env' <- case (not infPassed) of
              True  -> markUnsafeInfer tcg_env infErrs
              False -> return tcg_env
            when (packageTrustOn dflags) $ checkPkgTrust dflags pkgReqs
            let newTrust = pkgTrustReqs safePkgs infPkgs infPassed
            return tcg_env' { tcg_imports = impInfo `plusImportAvails` newTrust }
920

dterei's avatar
dterei committed
921
  where
922 923
    impInfo  = tcg_imports tcg_env     -- ImportAvails
    imports  = imp_mods impInfo        -- ImportedMods
dterei's avatar
dterei committed
924
    imports' = moduleEnvToList imports -- (Module, [ImportedModsVal])
925
    pkgReqs  = imp_trust_pkgs impInfo  -- [UnitId]