HscMain.hs 64 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 22 23 24 25
-- 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).
--
-- Warning messages are dealt with consistently throughout this API:
-- during compilation warnings are collected, and before any function
-- in @HscMain@ returns, the warnings are either printed, or turned
-- into a real compialtion error if the @-Werror@ flag is enabled.
26
--
dterei's avatar
dterei committed
27 28 29 30
-- (c) The GRASP/AQUA Project, Glasgow University, 1993-2000
--
-------------------------------------------------------------------------------

31
module HscMain
dterei's avatar
dterei committed
32
    (
33 34 35 36
    -- * Making an HscEnv
      newHscEnv

    -- * Compiling complete source files
37 38
    , Messager, batchMsg
    , HscStatus (..)
39 40 41 42
    , hscCompileOneShot
    , hscCompileCmmFile
    , hscCompileCore

43 44 45 46 47 48 49 50 51
    , genericHscCompileGetFrontendResult

    , genModDetails
    , hscSimpleIface
    , hscWriteIface
    , hscNormalIface
    , hscGenHardCode
    , hscInteractive

52
    -- * Running passes separately
Thomas Schilling's avatar
Thomas Schilling committed
53 54 55
    , hscParse
    , hscTypecheckRename
    , hscDesugar
Simon Marlow's avatar
Simon Marlow committed
56 57
    , makeSimpleIface
    , makeSimpleDetails
58 59 60 61 62 63
    , hscSimplify -- ToDo, shouldn't really export this

    -- * Support for interactive evaluation
    , hscParseIdentifier
    , hscTcRcLookupName
    , hscTcRnGetInfo
64
    , hscCheckSafe
dterei's avatar
dterei committed
65
    , hscGetSafe
66
#ifdef GHCI
dterei's avatar
dterei committed
67
    , hscIsGHCiMonad
68
    , hscGetModuleInterface
69
    , hscRnImportDecls
70
    , hscTcRnLookupRdrName
vivian's avatar
vivian committed
71
    , hscStmt, hscStmtWithLocation
72
    , hscDecls, hscDeclsWithLocation
vivian's avatar
vivian committed
73
    , hscTcExpr, hscImport, hscKcType
74
    , hscCompileCoreExpr
75 76
    -- * Low-level exports for hooks
    , hscCompileCoreExpr'
77
#endif
Edsko de Vries's avatar
Edsko de Vries committed
78 79
      -- We want to make sure that we export enough to be able to redefine
      -- hscFileFrontEnd in client code
80
    , hscParse', hscSimplify', hscDesugar', tcRnModule'
Edsko de Vries's avatar
Edsko de Vries committed
81
    , getHscEnv
82 83 84
    , hscSimpleIface', hscNormalIface'
    , oneShotMsg
    , hscFileFrontEnd, genericHscFrontend, dumpIfaceStats
85
    ) where
86

87
#ifdef GHCI
Simon Marlow's avatar
Simon Marlow committed
88
import Id
89
import BasicTypes       ( HValue )
90
import ByteCodeGen      ( byteCodeGen, coreExprToBCOs )
91
import Linker
92 93
import CoreTidy         ( tidyExpr )
import Type             ( Type )
94
import PrelNames
95
import {- Kind parts of -} Type         ( Kind )
96
import CoreMonad        ( lintInteractiveExpr )
97 98
import DsMeta           ( templateHaskellNames )
import VarEnv           ( emptyTidyEnv )
simonpj@microsoft.com's avatar
simonpj@microsoft.com committed
99
import Panic
100 101

import GHC.Exts
102 103
#endif

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

145
import DynFlags
146
import ErrUtils
147

148
import Outputable
149
import HscStats         ( ppSourceStats )
150
import HscTypes
151
import FastString
152
import UniqFM           ( emptyUFM )
153
import UniqSupply
154
import Bag
Thomas Schilling's avatar
Thomas Schilling committed
155
import Exception
156 157 158
import qualified Stream
import Stream (Stream)

159
import Util
Simon Marlow's avatar
Simon Marlow committed
160

161
import Data.List
Simon Marlow's avatar
Simon Marlow committed
162
import Control.Monad
163
import Data.Maybe
Simon Marlow's avatar
Simon Marlow committed
164
import Data.IORef
165
import System.FilePath as FilePath
166
import System.Directory
dterei's avatar
dterei committed
167

Thomas Schilling's avatar
Thomas Schilling committed
168
#include "HsVersions.h"
169

170

dterei's avatar
dterei committed
171 172 173 174 175
{- **********************************************************************
%*                                                                      *
                Initialisation
%*                                                                      *
%********************************************************************* -}
176

177
newHscEnv :: DynFlags -> IO HscEnv
178
newHscEnv dflags = do
dterei's avatar
dterei committed
179 180 181 182 183
    eps_var <- newIORef initExternalPackageState
    us      <- mkSplitUniqSupply 'r'
    nc_var  <- newIORef (initNameCache us knownKeyNames)
    fc_var  <- newIORef emptyUFM
    mlc_var <- newIORef emptyModuleEnv
184
    return HscEnv {  hsc_dflags       = dflags,
dterei's avatar
dterei committed
185 186
                     hsc_targets      = [],
                     hsc_mod_graph    = [],
187
                     hsc_IC           = emptyInteractiveContext dflags,
dterei's avatar
dterei committed
188 189 190 191 192
                     hsc_HPT          = emptyHomePackageTable,
                     hsc_EPS          = eps_var,
                     hsc_NC           = nc_var,
                     hsc_FC           = fc_var,
                     hsc_MLC          = mlc_var,
193
                     hsc_type_env_var = Nothing }
Thomas Schilling's avatar
Thomas Schilling committed
194

195

196
knownKeyNames :: [Name]      -- Put here to avoid loops involving DsMeta,
197
knownKeyNames =              -- where templateHaskellNames are defined
dterei's avatar
dterei committed
198
    map getName wiredInThings
dterei's avatar
dterei committed
199
        ++ basicKnownKeyNames
200
#ifdef GHCI
dterei's avatar
dterei committed
201
        ++ templateHaskellNames
202 203
#endif

204
-- -----------------------------------------------------------------------------
205

206
getWarnings :: Hsc WarningMessages
dterei's avatar
dterei committed
207
getWarnings = Hsc $ \_ w -> return (w, w)
208 209

clearWarnings :: Hsc ()
dterei's avatar
dterei committed
210
clearWarnings = Hsc $ \_ _ -> return ((), emptyBag)
211 212

logWarnings :: WarningMessages -> Hsc ()
dterei's avatar
dterei committed
213
logWarnings w = Hsc $ \_ w0 -> return ((), w0 `unionBags` w)
214 215

getHscEnv :: Hsc HscEnv
dterei's avatar
dterei committed
216
getHscEnv = Hsc $ \e w -> return (e, w)
217 218 219

handleWarnings :: Hsc ()
handleWarnings = do
dterei's avatar
dterei committed
220 221 222 223
    dflags <- getDynFlags
    w <- getWarnings
    liftIO $ printOrThrowWarnings dflags w
    clearWarnings
224 225 226 227 228

-- | 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
229 230
    logWarnings warns
    when (not $ isEmptyBag errs) $ throwErrors errs
231 232 233 234

-- | Throw some errors.
throwErrors :: ErrorMessages -> Hsc a
throwErrors = liftIO . throwIO . mkSrcErr
235 236 237 238 239

-- | 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
240
-- and signal success via by wrapping the result in a 'Maybe' type. This
241 242 243 244 245 246 247 248 249
-- 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
250
--     there should be warnings in the first result. That is, if the action
251 252 253
--     failed, it must have been due to the warnings (i.e., @-Werror@).
ioMsgMaybe :: IO (Messages, Maybe a) -> Hsc a
ioMsgMaybe ioA = do
254
    ((warns,errs), mb_r) <- liftIO ioA
dterei's avatar
dterei committed
255 256 257 258
    logWarnings warns
    case mb_r of
        Nothing -> throwErrors errs
        Just r  -> ASSERT( isEmptyBag errs ) return r
259 260 261 262 263

-- | 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
264 265 266
    ((warns,_errs), mb_r) <- liftIO $ ioA
    logWarnings warns
    return mb_r
267 268 269 270 271 272

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

#ifdef GHCI
hscTcRnLookupRdrName :: HscEnv -> RdrName -> IO [Name]
273 274 275
hscTcRnLookupRdrName hsc_env0 rdr_name = runInteractiveHsc hsc_env0 $ do
   hsc_env <- getHscEnv
   ioMsgMaybe $ tcRnLookupRdrName hsc_env rdr_name
276 277 278
#endif

hscTcRcLookupName :: HscEnv -> Name -> IO (Maybe TyThing)
279 280 281
hscTcRcLookupName hsc_env0 name = runInteractiveHsc hsc_env0 $ do
  hsc_env <- getHscEnv
  ioMsgMaybe' $ tcRnLookupName hsc_env name
dterei's avatar
dterei committed
282 283 284
      -- 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.
285

286
hscTcRnGetInfo :: HscEnv -> Name -> IO (Maybe (TyThing, Fixity, [ClsInst], [FamInst]))
287 288 289 290
hscTcRnGetInfo hsc_env0 name
  = runInteractiveHsc hsc_env0 $
    do { hsc_env <- getHscEnv
       ; ioMsgMaybe' $ tcRnGetInfo hsc_env name }
291 292

#ifdef GHCI
dterei's avatar
dterei committed
293
hscIsGHCiMonad :: HscEnv -> String -> IO Name
Edsko de Vries's avatar
Edsko de Vries committed
294
hscIsGHCiMonad hsc_env name
295
  = runHsc hsc_env $ ioMsgMaybe $ isGHCiMonad hsc_env name
dterei's avatar
dterei committed
296

297
hscGetModuleInterface :: HscEnv -> Module -> IO ModIface
298 299 300
hscGetModuleInterface hsc_env0 mod = runInteractiveHsc hsc_env0 $ do
  hsc_env <- getHscEnv
  ioMsgMaybe $ getModuleInterface hsc_env mod
301 302 303

-- -----------------------------------------------------------------------------
-- | Rename some import declarations
304
hscRnImportDecls :: HscEnv -> [LImportDecl RdrName] -> IO GlobalRdrEnv
305 306 307
hscRnImportDecls hsc_env0 import_decls = runInteractiveHsc hsc_env0 $ do
  hsc_env <- getHscEnv
  ioMsgMaybe $ tcRnImportDecls hsc_env import_decls
308 309
#endif

310
-- -----------------------------------------------------------------------------
Simon Marlow's avatar
Simon Marlow committed
311
-- | parse a file, returning the abstract syntax
312

313
hscParse :: HscEnv -> ModSummary -> IO HsParsedModule
314 315 316
hscParse hsc_env mod_summary = runHsc hsc_env $ hscParse' mod_summary

-- internal version, that doesn't fail due to -Werror
317
hscParse' :: ModSummary -> Hsc HsParsedModule
318
hscParse' mod_summary = 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
323 324 325
    --------------------------  Parser  ----------------
    liftIO $ showPass dflags "Parser"
    {-# SCC "Parser" #-} do
326 327 328 329

    -- 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
330 331 332
    buf <- case maybe_src_buf of
               Just b  -> return b
               Nothing -> liftIO $ hGetStringBuffer src_filename
333

dterei's avatar
dterei committed
334
    let loc = mkRealSrcLoc (mkFastString src_filename) 1 1
335

dterei's avatar
dterei committed
336 337
    case unP parseModule (mkPState dflags buf loc) of
        PFailed span err ->
Ian Lynagh's avatar
Ian Lynagh committed
338
            liftIO $ throwOneError (mkPlainErrMsg dflags span err)
339

dterei's avatar
dterei committed
340 341 342 343 344 345
        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
346 347 348 349 350 351 352 353 354 355 356 357 358 359 360

            -- 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
361
                            $ filter (not . (isPrefixOf "<"))
362 363 364 365 366 367
                            $ map unpackFS
                            $ srcfiles pst
                srcs1 = case ml_hs_file (ms_location mod_summary) of
                          Just f  -> filter (/= FilePath.normalise f) srcs0
                          Nothing -> srcs0

368 369 370 371 372
            -- sometimes we see source files from earlier
            -- preprocessing stages that cannot be found, so just
            -- filter them out:
            srcs2 <- liftIO $ filterM doesFileExist srcs1

373 374
            return HsParsedModule {
                      hpm_module    = rdr_module,
375
                      hpm_src_files = srcs2
376
                   }
Simon Marlow's avatar
Simon Marlow committed
377

Thomas Schilling's avatar
Thomas Schilling committed
378 379 380
-- 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
381
type RenamedStuff =
Simon Marlow's avatar
Simon Marlow committed
382
        (Maybe (HsGroup Name, [LImportDecl Name], Maybe [LIE Name],
383
                Maybe LHsDocString))
Simon Marlow's avatar
Simon Marlow committed
384

Thomas Schilling's avatar
Thomas Schilling committed
385
-- | Rename and typecheck a module, additionally returning the renamed syntax
386
hscTypecheckRename :: HscEnv -> ModSummary -> HsParsedModule
387
                   -> IO (TcGblEnv, RenamedStuff)
dterei's avatar
dterei committed
388
hscTypecheckRename hsc_env mod_summary rdr_module = runHsc hsc_env $ do
389
    tc_result <- tcRnModule' hsc_env mod_summary True rdr_module
Thomas Schilling's avatar
Thomas Schilling committed
390

391 392 393 394 395 396
        -- 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
397

398
    return (tc_result, rn_info)
Simon Marlow's avatar
Simon Marlow committed
399

400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421
-- 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

    tcSafeOK <- liftIO $ readIORef (tcg_safeInfer tcg_res)
    dflags   <- getDynFlags

    -- end of the Safe Haskell line, how to respond to user?
    if not (safeHaskellOn dflags) || (safeInferOn dflags && not tcSafeOK)
        -- if safe haskell off or safe infer failed, wipe trust
        then wipeTrust tcg_res emptyBag

        -- module safe, throw warning if needed
        else do
            tcg_res' <- hscCheckSafeImports tcg_res
            safe <- liftIO $ readIORef (tcg_safeInfer tcg_res')
            when (safe && wopt Opt_WarnSafe dflags)
                 (logWarnings $ unitBag $
Ian Lynagh's avatar
Ian Lynagh committed
422
                     mkPlainWarnMsg dflags (warnSafeOnLoc dflags) $ errSafe tcg_res')
423 424 425
            return tcg_res'
  where
    pprMod t  = ppr $ moduleName $ tcg_mod t
426
    errSafe t = quotes (pprMod t) <+> text "has been inferred as safe!"
427

Simon Marlow's avatar
Simon Marlow committed
428
-- | Convert a typechecked module to Core
429
hscDesugar :: HscEnv -> ModSummary -> TcGblEnv -> IO ModGuts
430
hscDesugar hsc_env mod_summary tc_result =
Ian Lynagh's avatar
Ian Lynagh committed
431
    runHsc hsc_env $ hscDesugar' (ms_location mod_summary) tc_result
432

Ian Lynagh's avatar
Ian Lynagh committed
433 434
hscDesugar' :: ModLocation -> TcGblEnv -> Hsc ModGuts
hscDesugar' mod_location tc_result = do
dterei's avatar
dterei committed
435
    hsc_env <- getHscEnv
Simon Marlow's avatar
Simon Marlow committed
436 437
    r <- ioMsgMaybe $
      {-# SCC "deSugar" #-}
Ian Lynagh's avatar
Ian Lynagh committed
438
      deSugar hsc_env mod_location tc_result
439

dterei's avatar
dterei committed
440 441 442 443
    -- 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
444

dterei's avatar
dterei committed
445
-- | Make a 'ModIface' from the results of typechecking. Used when
Simon Marlow's avatar
Simon Marlow committed
446 447 448 449
-- not optimising, and the interface doesn't need to contain any
-- unfoldings or other cross-module optimisation info.
-- ToDo: the old interface is only needed to get the version numbers,
-- we should use fingerprint versions instead.
450
makeSimpleIface :: HscEnv -> Maybe ModIface -> TcGblEnv -> ModDetails
451
                -> IO (ModIface,Bool)
452 453 454 455 456
makeSimpleIface hsc_env maybe_old_iface tc_result details = runHsc hsc_env $ do
    safe_mode <- hscGetSafeMode tc_result
    ioMsgMaybe $ do
        mkIfaceTc hsc_env (fmap mi_iface_hash maybe_old_iface) safe_mode
                  details tc_result
Simon Marlow's avatar
Simon Marlow committed
457

dterei's avatar
dterei committed
458
-- | Make a 'ModDetails' from the results of typechecking. Used when
Simon Marlow's avatar
Simon Marlow committed
459
-- typechecking only, as opposed to full compilation.
460 461
makeSimpleDetails :: HscEnv -> TcGblEnv -> IO ModDetails
makeSimpleDetails hsc_env tc_result = mkBootModDetailsTc hsc_env tc_result
Simon Marlow's avatar
Simon Marlow committed
462

463

dterei's avatar
dterei committed
464 465 466 467 468 469 470
{- **********************************************************************
%*                                                                      *
                The main compiler pipeline
%*                                                                      *
%********************************************************************* -}

{-
471 472 473 474
                   --------------------------------
                        The compilation proper
                   --------------------------------

dterei's avatar
dterei committed
475 476 477 478 479 480
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
481
targets byte-code.
dterei's avatar
dterei committed
482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506

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.
-}


507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526
type Messager = HscEnv -> (Int,Int) -> RecompileRequired -> ModSummary -> IO ()

genericHscCompileGetFrontendResult ::
                     Bool -- always do basic recompilation check?
                  -> Maybe TcGblEnv
                  -> Maybe Messager
                  -> HscEnv
                  -> ModSummary
                  -> SourceModified
                  -> Maybe ModIface  -- Old interface, if available
                  -> (Int,Int)       -- (i,n) = module i of n (for msgs)
                  -> IO (Either ModIface (TcGblEnv, Maybe Fingerprint))

genericHscCompileGetFrontendResult always_do_basic_recompilation_check m_tc_result
                                   mHscMessage hsc_env mod_summary source_modified mb_old_iface mod_index
    = do

    let msg what = case mHscMessage of
                   Just hscMessage -> hscMessage hsc_env mod_index what mod_summary
                   Nothing -> return ()
dterei's avatar
dterei committed
527

528 529 530
        skip iface = do
            msg UpToDate
            return $ Left iface
dterei's avatar
dterei committed
531

532 533 534 535
        compile mb_old_hash reason = do
            msg reason
            tc_result <- runHsc hsc_env $ genericHscFrontend mod_summary
            return $ Right (tc_result, mb_old_hash)
dterei's avatar
dterei committed
536 537 538 539

        stable = case source_modified of
                     SourceUnmodifiedAndStable -> True
                     _                         -> False
540

541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579
    case m_tc_result of
         Just tc_result
          | not always_do_basic_recompilation_check ->
             return $ Right (tc_result, Nothing)
         _ -> do
            (recomp_reqd, mb_checked_iface)
                <- {-# SCC "checkOldIface" #-}
                   checkOldIface hsc_env mod_summary
                                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) ->
                    -- 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.
                    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 ->
                        return $ Right (tc_result, mb_old_hash)

genericHscFrontend :: ModSummary -> Hsc TcGblEnv
580 581 582 583
genericHscFrontend mod_summary =
  getHooked hscFrontendHook genericHscFrontend' >>= ($ mod_summary)

genericHscFrontend' :: ModSummary -> Hsc TcGblEnv
Austin Seipp's avatar
Austin Seipp committed
584
genericHscFrontend' mod_summary = hscFileFrontEnd mod_summary
585

586 587 588 589
--------------------------------------------------------------
-- Compilers
--------------------------------------------------------------

590 591 592
hscCompileOneShot :: HscEnv
                  -> ModSummary
                  -> SourceModified
593
                  -> IO HscStatus
594 595 596
hscCompileOneShot env =
  lookupHook hscCompileOneShotHook hscCompileOneShot' (hsc_dflags env) env

Austin Seipp's avatar
Austin Seipp committed
597
-- Compile Haskell/boot in OneShot mode.
598 599 600 601
hscCompileOneShot' :: HscEnv
                   -> ModSummary
                   -> SourceModified
                   -> IO HscStatus
Austin Seipp's avatar
Austin Seipp committed
602
hscCompileOneShot' hsc_env mod_summary src_changed
603
  = do
dterei's avatar
dterei committed
604 605 606 607 608
    -- 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
        hsc_env' = hsc_env{ hsc_type_env_var = Just (mod, type_env_var) }
609

610 611 612 613
        msg what = oneShotMsg hsc_env' what

        skip = do msg UpToDate
                  dumpIfaceStats hsc_env'
614
                  return HscUpToDate
615 616 617 618

        compile mb_old_hash reason = runHsc hsc_env' $ do
            liftIO $ msg reason
            tc_result <- genericHscFrontend mod_summary
619
            guts0 <- hscDesugar' (ms_location mod_summary) tc_result
620 621
            dflags <- getDynFlags
            case hscTarget dflags of
622
                HscNothing -> return HscNotGeneratingCode
623 624 625 626 627
                _ ->
                    case ms_hsc_src mod_summary of
                    HsBootFile ->
                        do (iface, changed, _) <- hscSimpleIface' tc_result mb_old_hash
                           liftIO $ hscWriteIface dflags iface changed mod_summary
628
                           return HscUpdateBoot
629
                    _ ->
630
                        do guts <- hscSimplify' guts0
Austin Seipp's avatar
Austin Seipp committed
631
                           (iface, changed, _details, cgguts) <- hscNormalIface' guts mb_old_hash
632
                           liftIO $ hscWriteIface dflags iface changed mod_summary
633
                           return $ HscRecomp cgguts mod_summary
634

Simon Marlow's avatar
Comment  
Simon Marlow committed
635 636 637
        -- XXX This is always False, because in one-shot mode the
        -- concept of stability does not exist.  The driver never
        -- passes SourceUnmodifiedAndStable in here.
638 639 640
        stable = case src_changed of
                     SourceUnmodifiedAndStable -> True
                     _                         -> False
641

642 643 644 645 646 647 648
    (recomp_reqd, mb_checked_iface)
        <- {-# SCC "checkOldIface" #-}
           checkOldIface hsc_env' mod_summary src_changed Nothing
    -- 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
649

650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666
    case mb_checked_iface of
        Just iface | not (recompileRequired recomp_reqd) ->
            -- 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.
            if mi_used_th iface && not stable
            then compile mb_old_hash (RecompBecause "TH")
            else skip
        _ ->
            compile mb_old_hash recomp_reqd
667

668 669 670 671
--------------------------------------------------------------
-- NoRecomp handlers
--------------------------------------------------------------

672 673
genModDetails :: HscEnv -> ModIface -> IO ModDetails
genModDetails hsc_env old_iface
674
  = do
dterei's avatar
dterei committed
675
    new_details <- {-# SCC "tcRnIface" #-}
676 677
                   initIfaceCheck hsc_env (typecheckIface old_iface)
    dumpIfaceStats hsc_env
dterei's avatar
dterei committed
678
    return new_details
679

680 681 682 683
--------------------------------------------------------------
-- Progress displayers.
--------------------------------------------------------------

684 685
oneShotMsg :: HscEnv -> RecompileRequired -> IO ()
oneShotMsg hsc_env recomp =
dterei's avatar
dterei committed
686
    case recomp of
687
        UpToDate ->
688 689
            compilationProgressMsg (hsc_dflags hsc_env) $
                   "compilation IS NOT required"
690
        _ ->
691 692
            return ()

693 694
batchMsg :: Messager
batchMsg hsc_env mod_index recomp mod_summary =
dterei's avatar
dterei committed
695
    case recomp of
696 697 698
        MustCompile -> showMsg "Compiling " ""
        UpToDate
            | verbosity (hsc_dflags hsc_env) >= 2 -> showMsg "Skipping  " ""
dterei's avatar
dterei committed
699
            | otherwise -> return ()
700
        RecompBecause reason -> showMsg "Compiling " (" [" ++ reason ++ "]")
dterei's avatar
dterei committed
701
    where
Ian Lynagh's avatar
Ian Lynagh committed
702
        dflags = hsc_dflags hsc_env
703
        showMsg msg reason =
Ian Lynagh's avatar
Ian Lynagh committed
704
            compilationProgressMsg dflags $
705
            (showModuleIndex mod_index ++
Ian Lynagh's avatar
Ian Lynagh committed
706
            msg ++ showModMsg dflags (hscTarget dflags)
707 708
                              (recompileRequired recomp) mod_summary)
                ++ reason
709

710 711 712
--------------------------------------------------------------
-- FrontEnds
--------------------------------------------------------------
713 714

hscFileFrontEnd :: ModSummary -> Hsc TcGblEnv
715
hscFileFrontEnd mod_summary = do
716
    hpm <- hscParse' mod_summary
717
    hsc_env <- getHscEnv
718 719
    tcg_env <- tcRnModule' hsc_env mod_summary False hpm
    return tcg_env
720 721

--------------------------------------------------------------
722
-- Safe Haskell
723 724
--------------------------------------------------------------

725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744
-- 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.


745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764
-- Note [Safe Haskell Inference]
-- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-- Safe Haskell does Safe inference on modules that don't have any specific
-- safe haskell mode flag. The basic aproach to this is:
--   * 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.


-- | 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
765
    tcg_env' <- checkSafeImports dflags tcg_env
766 767 768
    case safeLanguageOn dflags of
        True -> do
            -- we nuke user written RULES in -XSafe
Ian Lynagh's avatar
Ian Lynagh committed
769
            logWarnings $ warns dflags (tcg_rules tcg_env')
770 771 772 773 774
            return tcg_env' { tcg_rules = [] }
        False
              -- user defined RULES, so not safe or already unsafe
            | safeInferOn dflags && not (null $ tcg_rules tcg_env') ||
              safeHaskell dflags == Sf_None
Ian Lynagh's avatar
Ian Lynagh committed
775
            -> wipeTrust tcg_env' $ warns dflags (tcg_rules tcg_env')
776

777
              -- trustworthy OR safe inferred with no RULES
778 779 780
            | otherwise
            -> return tcg_env'

dterei's avatar
dterei committed
781
  where
Ian Lynagh's avatar
Ian Lynagh committed
782 783 784
    warns dflags rules = listToBag $ map (warnRules dflags) rules
    warnRules dflags (L loc (HsRule n _ _ _ _ _ _)) =
        mkPlainWarnMsg dflags loc $
dterei's avatar
dterei committed
785 786
            text "Rule \"" <> ftext n <> text "\" ignored" $+$
            text "User defined rules are disabled under Safe Haskell"
787

788 789 790 791 792 793
-- | 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.
794
--
795 796 797 798 799
-- 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].
800 801
checkSafeImports :: DynFlags -> TcGblEnv -> Hsc TcGblEnv
checkSafeImports dflags tcg_env
802
    = do
803 804 805 806 807
        -- 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

808
        imps <- mapM condense imports'
809
        pkgs <- mapM checkSafe imps
dterei's avatar
dterei committed
810 811 812 813 814 815

        -- grab any safe haskell specific errors and restore old warnings
        errs <- getWarnings
        clearWarnings
        logWarnings oldErrs

816
        -- See the Note [Safe Haskell Inference]
dterei's avatar
dterei committed
817 818 819 820 821 822
        case (not $ isEmptyBag errs) of

            -- We have errors!
            True ->
                -- did we fail safe inference or fail -XSafe?
                case safeInferOn dflags of
823
                    True  -> wipeTrust tcg_env errs
dterei's avatar
dterei committed
824
                    False -> liftIO . throwIO . mkSrcErr $ errs
dterei's avatar
dterei committed
825

dterei's avatar
dterei committed
826 827
            -- All good matey!
            False -> do
828
                when (packageTrustOn dflags) $ checkPkgTrust dflags pkg_reqs
dterei's avatar
dterei committed
829 830 831
                -- add in trusted package requirements for this module
                let new_trust = emptyImportAvails { imp_trust_pkgs = catMaybes pkgs }
                return tcg_env { tcg_imports = imp_info `plusImportAvails` new_trust }
832

dterei's avatar
dterei committed
833 834 835 836 837 838 839 840 841
  where
    imp_info = tcg_imports tcg_env     -- ImportAvails
    imports  = imp_mods imp_info       -- ImportedMods
    imports' = moduleEnvToList imports -- (Module, [ImportedModsVal])
    pkg_reqs = imp_trust_pkgs imp_info -- [PackageId]

    condense :: (Module, [ImportedModsVal]) -> Hsc (Module, SrcSpan, IsSafeImport)
    condense (_, [])   = panic "HscMain.condense: Pattern match failure!"
    condense (m, x:xs) = do (_,_,l,s) <- foldlM cond' x xs
842 843 844 845
                            -- we turn all imports into safe ones when
                            -- inference mode is on.
                            let s' = if safeInferOn dflags then True else s
                            return (m, l, s')
dterei's avatar
dterei committed
846

dterei's avatar
dterei committed
847 848 849 850
    -- ImportedModsVal = (ModuleName, Bool, SrcSpan, IsSafeImport)
    cond' :: ImportedModsVal -> ImportedModsVal -> Hsc ImportedModsVal
    cond' v1@(m1,_,l1,s1) (_,_,_,s2)
        | s1 /= s2
Ian Lynagh's avatar
Ian Lynagh committed
851
        = throwErrors $ unitBag $ mkPlainErrMsg dflags l1
dterei's avatar
dterei committed
852 853 854 855
              (text "Module" <+> ppr m1 <+>
              (text $ "is imported both as a safe and unsafe import!"))
        | otherwise
        = return v1
Jan Stolarek's avatar
Jan Stolarek committed
856

857 858
    -- easier interface to work with
    checkSafe (_, _, False) = return Nothing
dterei's avatar
dterei committed
859
    checkSafe (m, l, True ) = fst `fmap` hscCheckSafe' dflags m l
dterei's avatar
dterei committed
860

861 862
-- | Check that a module is safe to import.
--
dterei's avatar
dterei committed
863 864 865
-- We return True to indicate the import is safe and False otherwise
-- although in the False case an exception may be thrown first.
hscCheckSafe :: HscEnv -> Module -> SrcSpan -> IO Bool
866 867
hscCheckSafe hsc_env m l = runHsc hsc_env $ do
    dflags <- getDynFlags
dterei's avatar
dterei committed
868 869 870 871
    pkgs <- snd `fmap` hscCheckSafe' dflags m l
    when (packageTrustOn dflags) $ checkPkgTrust dflags pkgs
    errs <- getWarnings
    return $ isEmptyBag errs
872

dterei's avatar
dterei committed
873 874 875 876 877 878 879 880 881 882
-- | Return if a module is trusted and the pkgs it depends on to be trusted.
hscGetSafe :: HscEnv -> Module -> SrcSpan -> IO (Bool, [PackageId])
hscGetSafe hsc_env m l = runHsc hsc_env $ do
    dflags       <- getDynFlags
    (self, pkgs) <- hscCheckSafe' dflags m l
    good         <- isEmptyBag `fmap` getWarnings
    clearWarnings -- don't want them printed...
    let pkgs' | Just p <- self = p:pkgs
              | otherwise      = pkgs
    return (good, pkgs')
Jan Stolarek's avatar
Jan Stolarek committed
883

dterei's avatar
dterei committed
884 885 886 887
-- | Is a module trusted? If not, throw or log errors depending on the type.
-- Return (regardless of trusted or not) if the trust type requires the modules
-- own package be trusted and a list of other packages required to be trusted
-- (these later ones haven't been checked) but the own package trust has been.
dterei's avatar
dterei committed
888
hscCheckSafe' :: DynFlags -> Module -> SrcSpan -> Hsc (Maybe PackageId, [PackageId])
889
hscCheckSafe' dflags m l = do
dterei's avatar
dterei committed
890
    (tw, pkgs) <- isModSafe m l
891
    case tw of
dterei's avatar
dterei committed
892 893 894
        False              -> return (Nothing, pkgs)
        True | isHomePkg m -> return (Nothing, pkgs)
             | otherwise   -> return (Just $ modulePackageId m, pkgs)
895
  where
dterei's avatar
dterei committed
896
    isModSafe :: Module -> SrcSpan -> Hsc (Bool, [PackageId])
dterei's avatar
dterei committed
897 898 899 900
    isModSafe m l = do
        iface <- lookup' m
        case iface of
            -- can't load iface to check trust!
Ian Lynagh's avatar
Ian Lynagh committed
901
            Nothing -> throwErrors $ unitBag $ mkPlainErrMsg dflags l
902 903
                         $ text "Can't load the interface file for" <+> ppr m
                           <> text ", to check that it can be safely imported"
dterei's avatar
dterei committed
904 905

            -- got iface, check trust
906
            Just iface' ->
dterei's avatar
dterei committed
907 908 909
                let trust = getSafeMode $ mi_trust iface'
                    trust_own_pkg = mi_trust_pkg iface'
                    -- check module is trusted
910
                    safeM = trust `elem` [Sf_SafeInferred, Sf_Safe, Sf_Trustworthy]
dterei's avatar
dterei committed
911 912
                    -- check package is trusted
                    safeP = packageTrusted trust trust_own_pkg m
dterei's avatar
dterei committed
913 914
                    -- pkg trust reqs
                    pkgRs = map fst $ filter snd $ dep_pkgs $ mi_deps iface'
dterei's avatar
dterei committed
915
                    -- General errors we throw but Safe errors we log
916 917 918 919 920 921 922
                    errs = case (safeM, safeP) of
                        (True, True ) -> emptyBag
                        (True, False) -> pkgTrustErr
                        (False, _   ) -> modTrustErr
                in do
                    logWarnings errs
                    return (trust == Sf_Trustworthy, pkgRs)
dterei's avatar
dterei committed
923 924

                where
925
                    pkgTrustErr = unitBag $ mkPlainErrMsg dflags l $
926 927
                        sep [ ppr (moduleName m)
                                <> text ": Can't be safely imported!"
928
                            , text "The package (" <> ppr (modulePackageId m)
929
                                <> text ") the module resides in isn't trusted."
930
                            ]
Ian Lynagh's avatar
Ian Lynagh committed
931
                    modTrustErr = unitBag $ mkPlainErrMsg dflags l $
932 933
                        sep [ ppr (moduleName m)
                                <> text ": Can't be safely imported!"
934
                            , text "The module itself isn't safe." ]
dterei's avatar
dterei committed
935

936 937 938 939
    -- | Check the package a module resides in is trusted. Safe compiled
    -- modules are trusted without requiring that their package is trusted. For
    -- trustworthy modules, modules in the home package are trusted but
    -- otherwise we check the package trust flag.
940
    packageTrusted :: SafeHaskellMode -> Bool -> Module -> Bool
dterei's avatar
dterei committed
941 942
    packageTrusted Sf_None             _ _ = False -- shouldn't hit these cases
    packageTrusted Sf_Unsafe           _ _ = False -- prefer for completeness.
943
    packageTrusted _ _ _
944 945 946
        | not (packageTrustOn dflags)      = True
    packageTrusted Sf_Safe         False _ = True
    packageTrusted Sf_SafeInferred False _ = True
947 948 949 950
    packageTrusted _ _ m
        | isHomePkg m = True
        | otherwise   = trusted $ getPackageDetails (pkgState dflags)
                                                    (modulePackageId m)
dterei's avatar
dterei committed
951

952 953 954 955 956 957 958
    lookup' :: Module -> Hsc (Maybe ModIface)
    lookup' m = do
        hsc_env <- getHscEnv
        hsc_eps <- liftIO $ hscEPS hsc_env
        let pkgIfaceT = eps_PIT hsc_eps
            homePkgT  = hsc_HPT hsc_env
            iface     = lookupIfaceByModule dflags homePkgT pkgIfaceT m
dterei's avatar
dterei committed
959 960 961 962 963 964 965 966
#ifdef GHCI
        -- the 'lookupIfaceByModule' method will always fail when calling from GHCi
        -- as the compiler hasn't filled in the various module tables
        -- so we need to call 'getModuleInterface' to load from disk
        iface' <- case iface of
            Just _  -> return iface
            Nothing -> snd `fmap` (liftIO $ getModuleInterface hsc_env m)
        return iface'
Jan Stolarek's avatar
Jan Stolarek committed
967
#else
968
        return iface
dterei's avatar
dterei committed
969 970
#endif