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[ghc.git] / compiler / main / HeaderInfo.hs
1 -----------------------------------------------------------------------------
2 --
3 -- | Parsing the top of a Haskell source file to get its module name,
4 -- imports and options.
5 --
6 -- (c) Simon Marlow 2005
7 -- (c) Lemmih 2006
8 --
9 -----------------------------------------------------------------------------
10
11 module HeaderInfo ( getImports
12 , getOptionsFromFile, getOptions
13 , optionsErrorMsgs,
14 checkProcessArgsResult ) where
15
16 #include "HsVersions.h"
17
18 import RdrName
19 import HscTypes
20 import Parser ( parseHeader )
21 import Lexer
22 import FastString
23 import HsSyn ( ImportDecl(..), HsModule(..) )
24 import Module ( ModuleName, moduleName )
25 import PrelNames ( gHC_PRIM, mAIN_NAME )
26 import StringBuffer
27 import SrcLoc
28 import DynFlags
29 import ErrUtils
30 import Util
31 import Outputable
32 import Pretty ()
33 import Maybes
34 import Bag ( emptyBag, listToBag, unitBag )
35
36 import MonadUtils ( MonadIO )
37 import Exception
38 import Control.Monad
39 import System.IO
40 import System.IO.Unsafe
41 import Data.List
42
43 ------------------------------------------------------------------------------
44
45 -- | Parse the imports of a source file.
46 --
47 -- Throws a 'SourceError' if parsing fails.
48 getImports :: GhcMonad m =>
49 DynFlags
50 -> StringBuffer -- ^ Parse this.
51 -> FilePath -- ^ Filename the buffer came from. Used for
52 -- reporting parse error locations.
53 -> FilePath -- ^ The original source filename (used for locations
54 -- in the function result)
55 -> m ([Located (ImportDecl RdrName)], [Located (ImportDecl RdrName)], Located ModuleName)
56 -- ^ The source imports, normal imports, and the module name.
57 getImports dflags buf filename source_filename = do
58 let loc = mkSrcLoc (mkFastString filename) 1 1
59 case unP parseHeader (mkPState buf loc dflags) of
60 PFailed span err -> parseError span err
61 POk pst rdr_module -> do
62 let _ms@(_warns, errs) = getMessages pst
63 -- don't log warnings: they'll be reported when we parse the file
64 -- for real. See #2500.
65 ms = (emptyBag, errs)
66 -- logWarnings warns
67 if errorsFound dflags ms
68 then liftIO $ throwIO $ mkSrcErr errs
69 else
70 case rdr_module of
71 L _ (HsModule mb_mod _ imps _ _ _) ->
72 let
73 main_loc = mkSrcLoc (mkFastString source_filename) 1 1
74 mod = mb_mod `orElse` L (srcLocSpan main_loc) mAIN_NAME
75 (src_idecls, ord_idecls) = partition (ideclSource.unLoc) imps
76 ordinary_imps = filter ((/= moduleName gHC_PRIM) . unLoc . ideclName . unLoc)
77 ord_idecls
78 -- GHC.Prim doesn't exist physically, so don't go looking for it.
79 in
80 return (src_idecls, ordinary_imps, mod)
81
82 parseError :: GhcMonad m => SrcSpan -> Message -> m a
83 parseError span err = throwOneError $ mkPlainErrMsg span err
84
85 --------------------------------------------------------------
86 -- Get options
87 --------------------------------------------------------------
88
89 -- | Parse OPTIONS and LANGUAGE pragmas of the source file.
90 --
91 -- Throws a 'SourceError' if flag parsing fails (including unsupported flags.)
92 getOptionsFromFile :: DynFlags
93 -> FilePath -- ^ Input file
94 -> IO [Located String] -- ^ Parsed options, if any.
95 getOptionsFromFile dflags filename
96 = Exception.bracket
97 (openBinaryFile filename ReadMode)
98 (hClose)
99 (\handle -> do
100 opts <- fmap getOptions' $ lazyGetToks dflags filename handle
101 seqList opts $ return opts)
102
103 blockSize :: Int
104 -- blockSize = 17 -- for testing :-)
105 blockSize = 1024
106
107 lazyGetToks :: DynFlags -> FilePath -> Handle -> IO [Located Token]
108 lazyGetToks dflags filename handle = do
109 buf <- hGetStringBufferBlock handle blockSize
110 unsafeInterleaveIO $ lazyLexBuf handle (pragState dflags buf loc) False
111 where
112 loc = mkSrcLoc (mkFastString filename) 1 1
113
114 lazyLexBuf :: Handle -> PState -> Bool -> IO [Located Token]
115 lazyLexBuf handle state eof = do
116 case unP (lexer return) state of
117 POk state' t -> do
118 -- pprTrace "lazyLexBuf" (text (show (buffer state'))) (return ())
119 if atEnd (buffer state') && not eof
120 -- if this token reached the end of the buffer, and we haven't
121 -- necessarily read up to the end of the file, then the token might
122 -- be truncated, so read some more of the file and lex it again.
123 then getMore handle state
124 else case t of
125 L _ ITeof -> return [t]
126 _other -> do rest <- lazyLexBuf handle state' eof
127 return (t : rest)
128 _ | not eof -> getMore handle state
129 | otherwise -> return [L (last_loc state) ITeof]
130 -- parser assumes an ITeof sentinel at the end
131
132 getMore :: Handle -> PState -> IO [Located Token]
133 getMore handle state = do
134 -- pprTrace "getMore" (text (show (buffer state))) (return ())
135 nextbuf <- hGetStringBufferBlock handle blockSize
136 if (len nextbuf == 0) then lazyLexBuf handle state True else do
137 newbuf <- appendStringBuffers (buffer state) nextbuf
138 unsafeInterleaveIO $ lazyLexBuf handle state{buffer=newbuf} False
139
140
141 getToks :: DynFlags -> FilePath -> StringBuffer -> [Located Token]
142 getToks dflags filename buf = lexAll (pragState dflags buf loc)
143 where
144 loc = mkSrcLoc (mkFastString filename) 1 1
145
146 lexAll state = case unP (lexer return) state of
147 POk _ t@(L _ ITeof) -> [t]
148 POk state' t -> t : lexAll state'
149 _ -> [L (last_loc state) ITeof]
150
151
152 -- | Parse OPTIONS and LANGUAGE pragmas of the source file.
153 --
154 -- Throws a 'SourceError' if flag parsing fails (including unsupported flags.)
155 getOptions :: DynFlags
156 -> StringBuffer -- ^ Input Buffer
157 -> FilePath -- ^ Source filename. Used for location info.
158 -> [Located String] -- ^ Parsed options.
159 getOptions dflags buf filename
160 = getOptions' (getToks dflags filename buf)
161
162 -- The token parser is written manually because Happy can't
163 -- return a partial result when it encounters a lexer error.
164 -- We want to extract options before the buffer is passed through
165 -- CPP, so we can't use the same trick as 'getImports'.
166 getOptions' :: [Located Token] -- Input buffer
167 -> [Located String] -- Options.
168 getOptions' toks
169 = parseToks toks
170 where
171 getToken (L _loc tok) = tok
172 getLoc (L loc _tok) = loc
173
174 parseToks (open:close:xs)
175 | IToptions_prag str <- getToken open
176 , ITclose_prag <- getToken close
177 = map (L (getLoc open)) (words str) ++
178 parseToks xs
179 parseToks (open:close:xs)
180 | ITinclude_prag str <- getToken open
181 , ITclose_prag <- getToken close
182 = map (L (getLoc open)) ["-#include",removeSpaces str] ++
183 parseToks xs
184 parseToks (open:close:xs)
185 | ITdocOptions str <- getToken open
186 , ITclose_prag <- getToken close
187 = map (L (getLoc open)) ["-haddock-opts", removeSpaces str]
188 ++ parseToks xs
189 parseToks (open:xs)
190 | ITdocOptionsOld str <- getToken open
191 = map (L (getLoc open)) ["-haddock-opts", removeSpaces str]
192 ++ parseToks xs
193 parseToks (open:xs)
194 | ITlanguage_prag <- getToken open
195 = parseLanguage xs
196 parseToks _ = []
197 parseLanguage (L loc (ITconid fs):rest)
198 = checkExtension (L loc fs) :
199 case rest of
200 (L _loc ITcomma):more -> parseLanguage more
201 (L _loc ITclose_prag):more -> parseToks more
202 (L loc _):_ -> languagePragParseError loc
203 [] -> panic "getOptions'.parseLanguage(1) went past eof token"
204 parseLanguage (tok:_)
205 = languagePragParseError (getLoc tok)
206 parseLanguage []
207 = panic "getOptions'.parseLanguage(2) went past eof token"
208
209 -----------------------------------------------------------------------------
210
211 -- | Complain about non-dynamic flags in OPTIONS pragmas.
212 --
213 -- Throws a 'SourceError' if the input list is non-empty claiming that the
214 -- input flags are unknown.
215 checkProcessArgsResult :: MonadIO m => [Located String] -> m ()
216 checkProcessArgsResult flags
217 = when (notNull flags) $
218 liftIO $ throwIO $ mkSrcErr $ listToBag $ map mkMsg flags
219 where mkMsg (L loc flag)
220 = mkPlainErrMsg loc $
221 (text "unknown flag in {-# OPTIONS #-} pragma:" <+>
222 text flag)
223
224 -----------------------------------------------------------------------------
225
226 checkExtension :: Located FastString -> Located String
227 checkExtension (L l ext)
228 -- Checks if a given extension is valid, and if so returns
229 -- its corresponding flag. Otherwise it throws an exception.
230 = let ext' = unpackFS ext in
231 if ext' `elem` supportedLanguages
232 || ext' `elem` (map ("No"++) supportedLanguages)
233 then L l ("-X"++ext')
234 else unsupportedExtnError l ext'
235
236 languagePragParseError :: SrcSpan -> a
237 languagePragParseError loc =
238 throw $ mkSrcErr $ unitBag $
239 (mkPlainErrMsg loc $
240 vcat [ text "Cannot parse LANGUAGE pragma"
241 , text "Expecting comma-separated list of language options,"
242 , text "each starting with a capital letter"
243 , nest 2 (text "E.g. {-# LANGUAGE RecordPuns, Generics #-}") ])
244
245 unsupportedExtnError :: SrcSpan -> String -> a
246 unsupportedExtnError loc unsup =
247 throw $ mkSrcErr $ unitBag $
248 mkPlainErrMsg loc $
249 text "Unsupported extension: " <> text unsup
250
251
252 optionsErrorMsgs :: [String] -> [Located String] -> FilePath -> Messages
253 optionsErrorMsgs unhandled_flags flags_lines _filename
254 = (emptyBag, listToBag (map mkMsg unhandled_flags_lines))
255 where unhandled_flags_lines = [ L l f | f <- unhandled_flags,
256 L l f' <- flags_lines, f == f' ]
257 mkMsg (L flagSpan flag) =
258 ErrUtils.mkPlainErrMsg flagSpan $
259 text "unknown flag in {-# OPTIONS #-} pragma:" <+> text flag
260