{-# LANGUAGE ScopedTypeVariables #-}
-----------------------------------------------------------------------------
--
-- Tasks running external programs for SysTools
--
-- (c) The GHC Team 2017
--
-----------------------------------------------------------------------------
module SysTools.Tasks where

import Exception
import ErrUtils
import DynFlags
import Outputable
import Platform
import Util

import Data.Char
import Data.List

import System.IO
import System.Process
import GhcPrelude

import LlvmCodeGen.Base (llvmVersionStr, supportedLlvmVersion)

import SysTools.Process
import SysTools.Info

{-
************************************************************************
*                                                                      *
\subsection{Running an external program}
*                                                                      *
************************************************************************
-}

runUnlit :: DynFlags -> [Option] -> IO ()
runUnlit dflags args = do
  let prog = pgm_L dflags
      opts = getOpts dflags opt_L
  runSomething dflags "Literate pre-processor" prog
               (map Option opts ++ args)

runCpp :: DynFlags -> [Option] -> IO ()
runCpp dflags args =   do
  let (p,args0) = pgm_P dflags
      args1 = map Option (getOpts dflags opt_P)
      args2 = [Option "-Werror" | gopt Opt_WarnIsError dflags]
                ++ [Option "-Wundef" | wopt Opt_WarnCPPUndef dflags]
  mb_env <- getGccEnv args2
  runSomethingFiltered dflags id  "C pre-processor" p
                       (args0 ++ args1 ++ args2 ++ args) Nothing mb_env

runPp :: DynFlags -> [Option] -> IO ()
runPp dflags args =   do
  let prog = pgm_F dflags
      opts = map Option (getOpts dflags opt_F)
  runSomething dflags "Haskell pre-processor" prog (args ++ opts)

runCc :: DynFlags -> [Option] -> IO ()
runCc dflags args =   do
  let (p,args0) = pgm_c dflags
      args1 = map Option (getOpts dflags opt_c)
      args2 = args0 ++ args1 ++ args
  mb_env <- getGccEnv args2
  runSomethingResponseFile dflags cc_filter "C Compiler" p args2 mb_env
 where
  -- discard some harmless warnings from gcc that we can't turn off
  cc_filter = unlines . doFilter . lines

  {-
  gcc gives warnings in chunks like so:
      In file included from /foo/bar/baz.h:11,
                       from /foo/bar/baz2.h:22,
                       from wibble.c:33:
      /foo/flibble:14: global register variable ...
      /foo/flibble:15: warning: call-clobbered r...
  We break it up into its chunks, remove any call-clobbered register
  warnings from each chunk, and then delete any chunks that we have
  emptied of warnings.
  -}
  doFilter = unChunkWarnings . filterWarnings . chunkWarnings []
  -- We can't assume that the output will start with an "In file inc..."
  -- line, so we start off expecting a list of warnings rather than a
  -- location stack.
  chunkWarnings :: [String] -- The location stack to use for the next
                            -- list of warnings
                -> [String] -- The remaining lines to look at
                -> [([String], [String])]
  chunkWarnings loc_stack [] = [(loc_stack, [])]
  chunkWarnings loc_stack xs
      = case break loc_stack_start xs of
        (warnings, lss:xs') ->
            case span loc_start_continuation xs' of
            (lsc, xs'') ->
                (loc_stack, warnings) : chunkWarnings (lss : lsc) xs''
        _ -> [(loc_stack, xs)]

  filterWarnings :: [([String], [String])] -> [([String], [String])]
  filterWarnings [] = []
  -- If the warnings are already empty then we are probably doing
  -- something wrong, so don't delete anything
  filterWarnings ((xs, []) : zs) = (xs, []) : filterWarnings zs
  filterWarnings ((xs, ys) : zs) = case filter wantedWarning ys of
                                       [] -> filterWarnings zs
                                       ys' -> (xs, ys') : filterWarnings zs

  unChunkWarnings :: [([String], [String])] -> [String]
  unChunkWarnings [] = []
  unChunkWarnings ((xs, ys) : zs) = xs ++ ys ++ unChunkWarnings zs

  loc_stack_start        s = "In file included from " `isPrefixOf` s
  loc_start_continuation s = "                 from " `isPrefixOf` s
  wantedWarning w
   | "warning: call-clobbered register used" `isContainedIn` w = False
   | otherwise = True

isContainedIn :: String -> String -> Bool
xs `isContainedIn` ys = any (xs `isPrefixOf`) (tails ys)

-- | Run the linker with some arguments and return the output
askLd :: DynFlags -> [Option] -> IO String
askLd dflags args = do
  let (p,args0) = pgm_l dflags
      args1     = map Option (getOpts dflags opt_l)
      args2     = args0 ++ args1 ++ args
  mb_env <- getGccEnv args2
  runSomethingWith dflags "gcc" p args2 $ \real_args ->
    readCreateProcessWithExitCode' (proc p real_args){ env = mb_env }

runSplit :: DynFlags -> [Option] -> IO ()
runSplit dflags args = do
  let (p,args0) = pgm_s dflags
  runSomething dflags "Splitter" p (args0++args)

runAs :: DynFlags -> [Option] -> IO ()
runAs dflags args = do
  let (p,args0) = pgm_a dflags
      args1 = map Option (getOpts dflags opt_a)
      args2 = args0 ++ args1 ++ args
  mb_env <- getGccEnv args2
  runSomethingFiltered dflags id "Assembler" p args2 Nothing mb_env

-- | Run the LLVM Optimiser
runLlvmOpt :: DynFlags -> [Option] -> IO ()
runLlvmOpt dflags args = do
  let (p,args0) = pgm_lo dflags
      args1 = map Option (getOpts dflags opt_lo)
  runSomething dflags "LLVM Optimiser" p (args0 ++ args1 ++ args)

-- | Run the LLVM Compiler
runLlvmLlc :: DynFlags -> [Option] -> IO ()
runLlvmLlc dflags args = do
  let (p,args0) = pgm_lc dflags
      args1 = map Option (getOpts dflags opt_lc)
  runSomething dflags "LLVM Compiler" p (args0 ++ args1 ++ args)

-- | Run the clang compiler (used as an assembler for the LLVM
-- backend on OS X as LLVM doesn't support the OS X system
-- assembler)
runClang :: DynFlags -> [Option] -> IO ()
runClang dflags args = do
  let (clang,_) = pgm_lcc dflags
      -- be careful what options we call clang with
      -- see #5903 and #7617 for bugs caused by this.
      (_,args0) = pgm_a dflags
      args1 = map Option (getOpts dflags opt_a)
      args2 = args0 ++ args1 ++ args
  mb_env <- getGccEnv args2
  Exception.catch (do
        runSomethingFiltered dflags id "Clang (Assembler)" clang args2 Nothing mb_env
    )
    (\(err :: SomeException) -> do
        errorMsg dflags $
            text ("Error running clang! you need clang installed to use the" ++
                  " LLVM backend") $+$
            text "(or GHC tried to execute clang incorrectly)"
        throwIO err
    )

-- | Figure out which version of LLVM we are running this session
figureLlvmVersion :: DynFlags -> IO (Maybe (Int, Int))
figureLlvmVersion dflags = do
  let (pgm,opts) = pgm_lc dflags
      args = filter notNull (map showOpt opts)
      -- we grab the args even though they should be useless just in
      -- case the user is using a customised 'llc' that requires some
      -- of the options they've specified. llc doesn't care what other
      -- options are specified when '-version' is used.
      args' = args ++ ["-version"]
  ver <- catchIO (do
              (pin, pout, perr, _) <- runInteractiveProcess pgm args'
                                              Nothing Nothing
              {- > llc -version
                  LLVM (http://llvm.org/):
                    LLVM version 3.5.2
                    ...
              -}
              hSetBinaryMode pout False
              _     <- hGetLine pout
              vline <- dropWhile (not . isDigit) `fmap` hGetLine pout
              v     <- case span (/= '.') vline of
                        ("",_)  -> fail "no digits!"
                        (x,y) -> return (read x
                                        , read $ takeWhile isDigit $ drop 1 y)

              hClose pin
              hClose pout
              hClose perr
              return $ Just v
            )
            (\err -> do
                debugTraceMsg dflags 2
                    (text "Error (figuring out LLVM version):" <+>
                      text (show err))
                errorMsg dflags $ vcat
                    [ text "Warning:", nest 9 $
                          text "Couldn't figure out LLVM version!" $$
                          text ("Make sure you have installed LLVM " ++
                                llvmVersionStr supportedLlvmVersion) ]
                return Nothing)
  return ver


runLink :: DynFlags -> [Option] -> IO ()
runLink dflags args = do
  -- See Note [Run-time linker info]
  linkargs <- neededLinkArgs `fmap` getLinkerInfo dflags
  let (p,args0) = pgm_l dflags
      args1     = map Option (getOpts dflags opt_l)
      args2     = args0 ++ linkargs ++ args1 ++ args
  mb_env <- getGccEnv args2
  runSomethingResponseFile dflags ld_filter "Linker" p args2 mb_env
  where
    ld_filter = case (platformOS (targetPlatform dflags)) of
                  OSSolaris2 -> sunos_ld_filter
                  _ -> id
{-
  SunOS/Solaris ld emits harmless warning messages about unresolved
  symbols in case of compiling into shared library when we do not
  link against all the required libs. That is the case of GHC which
  does not link against RTS library explicitly in order to be able to
  choose the library later based on binary application linking
  parameters. The warnings look like:

Undefined                       first referenced
  symbol                             in file
stg_ap_n_fast                       ./T2386_Lib.o
stg_upd_frame_info                  ./T2386_Lib.o
templatezmhaskell_LanguageziHaskellziTHziLib_litE_closure ./T2386_Lib.o
templatezmhaskell_LanguageziHaskellziTHziLib_appE_closure ./T2386_Lib.o
templatezmhaskell_LanguageziHaskellziTHziLib_conE_closure ./T2386_Lib.o
templatezmhaskell_LanguageziHaskellziTHziSyntax_mkNameGzud_closure ./T2386_Lib.o
newCAF                              ./T2386_Lib.o
stg_bh_upd_frame_info               ./T2386_Lib.o
stg_ap_ppp_fast                     ./T2386_Lib.o
templatezmhaskell_LanguageziHaskellziTHziLib_stringL_closure ./T2386_Lib.o
stg_ap_p_fast                       ./T2386_Lib.o
stg_ap_pp_fast                      ./T2386_Lib.o
ld: warning: symbol referencing errors

  this is actually coming from T2386 testcase. The emitting of those
  warnings is also a reason why so many TH testcases fail on Solaris.

  Following filter code is SunOS/Solaris linker specific and should
  filter out only linker warnings. Please note that the logic is a
  little bit more complex due to the simple reason that we need to preserve
  any other linker emitted messages. If there are any. Simply speaking
  if we see "Undefined" and later "ld: warning:..." then we omit all
  text between (including) the marks. Otherwise we copy the whole output.
-}
    sunos_ld_filter :: String -> String
    sunos_ld_filter = unlines . sunos_ld_filter' . lines
    sunos_ld_filter' x = if (undefined_found x && ld_warning_found x)
                          then (ld_prefix x) ++ (ld_postfix x)
                          else x
    breakStartsWith x y = break (isPrefixOf x) y
    ld_prefix = fst . breakStartsWith "Undefined"
    undefined_found = not . null . snd . breakStartsWith "Undefined"
    ld_warn_break = breakStartsWith "ld: warning: symbol referencing errors"
    ld_postfix = tail . snd . ld_warn_break
    ld_warning_found = not . null . snd . ld_warn_break


runLibtool :: DynFlags -> [Option] -> IO ()
runLibtool dflags args = do
  linkargs <- neededLinkArgs `fmap` getLinkerInfo dflags
  let args1      = map Option (getOpts dflags opt_l)
      args2      = [Option "-static"] ++ args1 ++ args ++ linkargs
      libtool    = pgm_libtool dflags
  mb_env <- getGccEnv args2
  runSomethingFiltered dflags id "Linker" libtool args2 Nothing mb_env

runAr :: DynFlags -> Maybe FilePath -> [Option] -> IO ()
runAr dflags cwd args = do
  let ar = pgm_ar dflags
  runSomethingFiltered dflags id "Ar" ar args cwd Nothing

askAr :: DynFlags -> Maybe FilePath -> [Option] -> IO String
askAr dflags mb_cwd args = do
  let ar = pgm_ar dflags
  runSomethingWith dflags "Ar" ar args $ \real_args ->
    readCreateProcessWithExitCode' (proc ar real_args){ cwd = mb_cwd }

runRanlib :: DynFlags -> [Option] -> IO ()
runRanlib dflags args = do
  let ranlib = pgm_ranlib dflags
  runSomethingFiltered dflags id "Ranlib" ranlib args Nothing Nothing

runMkDLL :: DynFlags -> [Option] -> IO ()
runMkDLL dflags args = do
  let (p,args0) = pgm_dll dflags
      args1 = args0 ++ args
  mb_env <- getGccEnv (args0++args)
  runSomethingFiltered dflags id "Make DLL" p args1 Nothing mb_env

runWindres :: DynFlags -> [Option] -> IO ()
runWindres dflags args = do
  let (gcc, gcc_args) = pgm_c dflags
      windres = pgm_windres dflags
      opts = map Option (getOpts dflags opt_windres)
      quote x = "\"" ++ x ++ "\""
      args' = -- If windres.exe and gcc.exe are in a directory containing
              -- spaces then windres fails to run gcc. We therefore need
              -- to tell it what command to use...
              Option ("--preprocessor=" ++
                      unwords (map quote (gcc :
                                          map showOpt gcc_args ++
                                          map showOpt opts ++
                                          ["-E", "-xc", "-DRC_INVOKED"])))
              -- ...but if we do that then if windres calls popen then
              -- it can't understand the quoting, so we have to use
              -- --use-temp-file so that it interprets it correctly.
              -- See #1828.
            : Option "--use-temp-file"
            : args
  mb_env <- getGccEnv gcc_args
  runSomethingFiltered dflags id "Windres" windres args' Nothing mb_env

touch :: DynFlags -> String -> String -> IO ()
touch dflags purpose arg =
  runSomething dflags purpose (pgm_T dflags) [FileOption "" arg]
