+
+dopt_set :: DynFlags -> DynFlag -> DynFlags
+dopt_set dfs f = dfs{ flags = f : flags dfs }
+
+dopt_unset :: DynFlags -> DynFlag -> DynFlags
+dopt_unset dfs f = dfs{ flags = filter (/= f) (flags dfs) }
+
+getOpts :: (DynFlags -> [a]) -> IO [a]
+ -- We add to the options from the front, so we need to reverse the list
+getOpts opts = dynFlag opts >>= return . reverse
+
+-- we can only switch between HscC, HscAsmm, and HscILX with dynamic flags
+-- (-fvia-C, -fasm, -filx respectively).
+setLang l = updDynFlags (\ dfs -> case hscLang dfs of
+ HscC -> dfs{ hscLang = l }
+ HscAsm -> dfs{ hscLang = l }
+ HscILX -> dfs{ hscLang = l }
+ _ -> dfs)
+
+getVerbFlag = do
+ verb <- dynFlag verbosity
+ if verb >= 3 then return "-v" else return ""
+
+-----------------------------------------------------------------------------
+-- Setting the optimisation level
+
+setOptLevel :: Int -> IO ()
+setOptLevel n
+ = do dflags <- getDynFlags
+ if hscLang dflags == HscInterpreted && n > 0
+ then putStr "warning: -O conflicts with --interactive; -O ignored.\n"
+ else updDynFlags (setOptLevel' n)
+
+setOptLevel' n dfs
+ = if (n >= 1)
+ then dfs2{ hscLang = HscC, optLevel = n } -- turn on -fvia-C with -O
+ else dfs2{ optLevel = n }
+ where
+ dfs1 = foldr (flip dopt_unset) dfs remove_dopts
+ dfs2 = foldr (flip dopt_set) dfs1 extra_dopts
+
+ extra_dopts
+ | n == 0 = opt_0_dopts
+ | otherwise = opt_1_dopts
+
+ remove_dopts
+ | n == 0 = opt_1_dopts
+ | otherwise = opt_0_dopts
+
+opt_0_dopts = [
+ Opt_IgnoreInterfacePragmas,
+ Opt_OmitInterfacePragmas
+ ]
+
+opt_1_dopts = [
+ Opt_IgnoreAsserts,
+ Opt_DoEtaReduction,
+ Opt_CaseMerge
+ ]
+
+-- Core-to-core phases:
+
+buildCoreToDo :: DynFlags -> [CoreToDo]
+buildCoreToDo dflags = core_todo
+ where
+ opt_level = optLevel dflags
+ max_iter = maxSimplIterations dflags
+ strictness = dopt Opt_Strictness dflags
+ full_laziness = dopt Opt_FullLaziness dflags
+ cse = dopt Opt_CSE dflags
+ rule_check = ruleCheck dflags
+
+ core_todo =
+ if opt_level == 0 then
+ [
+ CoreDoSimplify (SimplPhase 0) [
+ MaxSimplifierIterations max_iter
+ ]
+ ]
+
+ else {- opt_level >= 1 -} [
+
+ -- initial simplify: mk specialiser happy: minimum effort please
+ CoreDoSimplify SimplGently [
+ -- Simplify "gently"
+ -- Don't inline anything till full laziness has bitten
+ -- In particular, inlining wrappers inhibits floating
+ -- e.g. ...(case f x of ...)...
+ -- ==> ...(case (case x of I# x# -> fw x#) of ...)...
+ -- ==> ...(case x of I# x# -> case fw x# of ...)...
+ -- and now the redex (f x) isn't floatable any more
+ -- Similarly, don't apply any rules until after full
+ -- laziness. Notably, list fusion can prevent floating.
+
+ NoCaseOfCase,
+ -- Don't do case-of-case transformations.
+ -- This makes full laziness work better
+ MaxSimplifierIterations max_iter
+ ],
+
+ -- Specialisation is best done before full laziness
+ -- so that overloaded functions have all their dictionary lambdas manifest
+ CoreDoSpecialising,
+
+ if full_laziness then CoreDoFloatOutwards (FloatOutSw False False)
+ else CoreDoNothing,
+
+ CoreDoFloatInwards,
+
+ CoreDoSimplify (SimplPhase 2) [
+ -- Want to run with inline phase 2 after the specialiser to give
+ -- maximum chance for fusion to work before we inline build/augment
+ -- in phase 1. This made a difference in 'ansi' where an
+ -- overloaded function wasn't inlined till too late.
+ MaxSimplifierIterations max_iter
+ ],
+ case rule_check of { Just pat -> CoreDoRuleCheck 2 pat; Nothing -> CoreDoNothing },
+
+ CoreDoSimplify (SimplPhase 1) [
+ -- Need inline-phase2 here so that build/augment get
+ -- inlined. I found that spectral/hartel/genfft lost some useful
+ -- strictness in the function sumcode' if augment is not inlined
+ -- before strictness analysis runs
+ MaxSimplifierIterations max_iter
+ ],
+ case rule_check of { Just pat -> CoreDoRuleCheck 1 pat; Nothing -> CoreDoNothing },
+
+ CoreDoSimplify (SimplPhase 0) [
+ -- Phase 0: allow all Ids to be inlined now
+ -- This gets foldr inlined before strictness analysis
+
+ MaxSimplifierIterations 3
+ -- At least 3 iterations because otherwise we land up with
+ -- huge dead expressions because of an infelicity in the
+ -- simpifier.
+ -- let k = BIG in foldr k z xs
+ -- ==> let k = BIG in letrec go = \xs -> ...(k x).... in go xs
+ -- ==> let k = BIG in letrec go = \xs -> ...(BIG x).... in go xs
+ -- Don't stop now!
+
+ ],
+ case rule_check of { Just pat -> CoreDoRuleCheck 0 pat; Nothing -> CoreDoNothing },
+
+#ifdef OLD_STRICTNESS
+ CoreDoOldStrictness
+#endif
+ if strictness then CoreDoStrictness else CoreDoNothing,
+ CoreDoWorkerWrapper,
+ CoreDoGlomBinds,
+
+ CoreDoSimplify (SimplPhase 0) [
+ MaxSimplifierIterations max_iter
+ ],
+
+ if full_laziness then
+ CoreDoFloatOutwards (FloatOutSw False -- Not lambdas
+ True) -- Float constants
+ else CoreDoNothing,
+ -- nofib/spectral/hartel/wang doubles in speed if you
+ -- do full laziness late in the day. It only happens
+ -- after fusion and other stuff, so the early pass doesn't
+ -- catch it. For the record, the redex is
+ -- f_el22 (f_el21 r_midblock)
+
+
+ -- We want CSE to follow the final full-laziness pass, because it may
+ -- succeed in commoning up things floated out by full laziness.
+ -- CSE used to rely on the no-shadowing invariant, but it doesn't any more
+
+ if cse then CoreCSE else CoreDoNothing,
+
+ CoreDoFloatInwards,
+
+-- Case-liberation for -O2. This should be after
+-- strictness analysis and the simplification which follows it.
+
+ case rule_check of { Just pat -> CoreDoRuleCheck 0 pat; Nothing -> CoreDoNothing },
+
+ if opt_level >= 2 then
+ CoreLiberateCase
+ else
+ CoreDoNothing,
+ if opt_level >= 2 then
+ CoreDoSpecConstr
+ else
+ CoreDoNothing,
+
+ -- Final clean-up simplification:
+ CoreDoSimplify (SimplPhase 0) [
+ MaxSimplifierIterations max_iter
+ ]
+ ]
+
+-- --------------------------------------------------------------------------
+-- Mess about with the mutable variables holding the dynamic arguments
+
+-- v_InitDynFlags
+-- is the "baseline" dynamic flags, initialised from
+-- the defaults and command line options, and updated by the
+-- ':s' command in GHCi.
+--
+-- v_DynFlags
+-- is the dynamic flags for the current compilation. It is reset
+-- to the value of v_InitDynFlags before each compilation, then
+-- updated by reading any OPTIONS pragma in the current module.
+
+GLOBAL_VAR(v_InitDynFlags, defaultDynFlags, DynFlags)
+GLOBAL_VAR(v_DynFlags, defaultDynFlags, DynFlags)
+
+setDynFlags :: DynFlags -> IO ()
+setDynFlags dfs = writeIORef v_DynFlags dfs
+
+saveDynFlags :: IO ()
+saveDynFlags = do dfs <- readIORef v_DynFlags
+ writeIORef v_InitDynFlags dfs
+
+restoreDynFlags :: IO DynFlags
+restoreDynFlags = do dfs <- readIORef v_InitDynFlags
+ writeIORef v_DynFlags dfs
+ return dfs
+
+getDynFlags :: IO DynFlags
+getDynFlags = readIORef v_DynFlags
+
+updDynFlags :: (DynFlags -> DynFlags) -> IO ()
+updDynFlags f = do dfs <- readIORef v_DynFlags
+ writeIORef v_DynFlags (f dfs)
+
+dynFlag :: (DynFlags -> a) -> IO a
+dynFlag f = do dflags <- readIORef v_DynFlags; return (f dflags)
+
+setDynFlag, unSetDynFlag :: DynFlag -> IO ()
+setDynFlag f = updDynFlags (\dfs -> dopt_set dfs f)
+unSetDynFlag f = updDynFlags (\dfs -> dopt_unset dfs f)
+\end{code}
+
+
+%************************************************************************
+%* *
+\subsection{Warnings}
+%* *
+%************************************************************************
+
+\begin{code}
+standardWarnings
+ = [ Opt_WarnDeprecations,
+ Opt_WarnOverlappingPatterns,
+ Opt_WarnMissingFields,
+ Opt_WarnMissingMethods,
+ Opt_WarnDuplicateExports
+ ]
+
+minusWOpts
+ = standardWarnings ++
+ [ Opt_WarnUnusedBinds,
+ Opt_WarnUnusedMatches,
+ Opt_WarnUnusedImports,
+ Opt_WarnIncompletePatterns,
+ Opt_WarnDodgyImports
+ ]
+
+minusWallOpts
+ = minusWOpts ++
+ [ Opt_WarnTypeDefaults,
+ Opt_WarnNameShadowing,
+ Opt_WarnMissingSigs,
+ Opt_WarnHiShadows
+ ]