%
-% (c) The GRASP/AQUA Project, Glasgow University, 1992-1996
+% (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
%
\section[Desugar]{@deSugar@: the main function}
\begin{code}
-module Desugar ( deSugar, pprDsWarnings ) where
+module Desugar ( deSugar, deSugarExpr ) where
#include "HsVersions.h"
-import CmdLineOpts ( opt_D_dump_ds )
-import HsSyn ( HsBinds, HsExpr, MonoBinds
- )
-import TcHsSyn ( TypecheckedMonoBinds, TypecheckedHsExpr
- )
+import CmdLineOpts ( DynFlag(..), dopt, opt_SccProfilingOn )
+import HscTypes ( ModGuts(..), ModGuts, HscEnv(..),
+ Dependencies(..), TypeEnv,
+ unQualInScope )
+import HsSyn ( MonoBinds, RuleDecl(..), RuleBndr(..),
+ HsExpr(..), HsBinds(..), MonoBinds(..) )
+import TcHsSyn ( TypecheckedRuleDecl, TypecheckedHsExpr )
+import TcRnTypes ( TcGblEnv(..), ImportAvails(..) )
+import MkIface ( mkUsageInfo )
+import Id ( Id )
import CoreSyn
-import PprCore ( pprCoreBindings )
-import Name ( isExported )
+import PprCore ( pprIdRules, pprCoreExpr )
+import Subst ( substExpr, mkSubst, mkInScopeSet )
import DsMonad
-import DsBinds ( dsMonoBinds )
-import DsUtils
-
-import Bag ( unionBags, isEmptyBag )
-import BasicTypes ( Module, RecFlag(..) )
-import CmdLineOpts ( opt_DoCoreLinting, opt_SccGroup, opt_SccProfilingOn )
-import CostCentre ( IsCafCC(..), mkAutoCC )
-import CoreLift ( liftCoreBindings )
-import CoreLint ( lintCoreBindings )
-import Id ( nullIdEnv, mkIdEnv, idType,
- DictVar, GenId, Id )
-import ErrUtils ( dumpIfSet, doIfSet )
+import DsExpr ( dsExpr )
+import DsBinds ( dsMonoBinds, AutoScc(..) )
+import DsForeign ( dsForeigns )
+import DsExpr () -- Forces DsExpr to be compiled; DsBinds only
+ -- depends on DsExpr.hi-boot.
+import Module ( Module, moduleEnvElts, emptyModuleEnv )
+import Id ( Id )
+import RdrName ( GlobalRdrEnv )
+import NameSet
+import VarEnv
+import VarSet
+import Bag ( isEmptyBag, mapBag, emptyBag )
+import CoreLint ( showPass, endPass )
+import ErrUtils ( doIfSet, dumpIfSet_dyn, pprBagOfWarnings,
+ addShortWarnLocLine, errorsFound )
import Outputable
-import UniqSupply ( splitUniqSupply, UniqSupply )
+import qualified Pretty
+import UniqSupply ( mkSplitUniqSupply )
+import SrcLoc ( SrcLoc )
+import DATA_IOREF ( readIORef )
+import FastString
\end{code}
-The only trick here is to get the @DsMonad@ stuff off to a good
-start.
+%************************************************************************
+%* *
+%* The main function: deSugar
+%* *
+%************************************************************************
\begin{code}
-deSugar :: UniqSupply -- name supply
- -> Module -- module name
- -> TypecheckedMonoBinds
- -> IO [CoreBinding] -- output
+deSugar :: HscEnv -> TcGblEnv -> IO (Maybe ModGuts)
+-- Can modify PCS by faulting in more declarations
-deSugar us mod_name all_binds
- = let
- (us1, us2) = splitUniqSupply us
-
- module_and_group = (mod_name, grp_name)
- grp_name = case opt_SccGroup of
- Just xx -> _PK_ xx
- Nothing -> mod_name -- default: module name
+deSugar hsc_env
+ (TcGblEnv { tcg_mod = mod,
+ tcg_type_env = type_env,
+ tcg_imports = imports,
+ tcg_exports = exports,
+ tcg_dus = dus,
+ tcg_inst_uses = dfun_uses_var,
+ tcg_rdr_env = rdr_env,
+ tcg_fix_env = fix_env,
+ tcg_deprecs = deprecs,
+ tcg_insts = insts,
+ tcg_binds = binds,
+ tcg_fords = fords,
+ tcg_rules = rules })
+ = do { showPass dflags "Desugar"
- (core_prs, ds_warns) = initDs us1 nullIdEnv module_and_group
- (dsMonoBinds opt_SccProfilingOn all_binds [])
+ -- Do desugaring
+ ; let { is_boot = imp_dep_mods imports }
+ ; (results, warnings) <- initDs hsc_env mod type_env is_boot $
+ dsProgram binds rules fords
- ds_binds = liftCoreBindings us2 [Rec core_prs]
- in
+ ; let { (ds_binds, ds_rules, ds_fords) = results
+ ; warns = mapBag mk_warn warnings
+ ; warn_doc = pprBagOfWarnings warns }
-- Display any warnings
- doIfSet (not (isEmptyBag ds_warns))
- (printErrs (pprDsWarnings ds_warns)) >>
+ ; doIfSet (not (isEmptyBag warnings))
+ (printErrs warn_doc)
+
+ -- If warnings are considered errors, leave.
+ ; if errorsFound dflags (warns, emptyBag)
+ then return Nothing
+ else do
-- Lint result if necessary
- lintCoreBindings "Desugarer" False ds_binds >>
+ { endPass dflags "Desugar" Opt_D_dump_ds ds_binds
-- Dump output
- dumpIfSet opt_D_dump_ds "Desugared:"
- (pprCoreBindings ds_binds) >>
+ ; doIfSet (dopt Opt_D_dump_ds dflags)
+ (printDump (ppr_ds_rules ds_rules))
+
+ ; dfun_uses <- readIORef dfun_uses_var -- What dfuns are used
+ ; let used_names = allUses dus emptyNameSet `unionNameSets` dfun_uses
+ ; usages <- mkUsageInfo hsc_env imports used_names
+ ; let
+ deps = Deps { dep_mods = moduleEnvElts (imp_dep_mods imports),
+ dep_pkgs = imp_dep_pkgs imports,
+ dep_orphs = imp_orphs imports }
+ mod_guts = ModGuts {
+ mg_module = mod,
+ mg_exports = exports,
+ mg_deps = deps,
+ mg_usages = usages,
+ mg_dir_imps = [m | (m,_) <- moduleEnvElts (imp_mods imports)],
+ mg_rdr_env = rdr_env,
+ mg_fix_env = fix_env,
+ mg_deprecs = deprecs,
+ mg_types = type_env,
+ mg_insts = insts,
+ mg_rules = ds_rules,
+ mg_binds = ds_binds,
+ mg_foreign = ds_fords }
+
+ ; return (Just mod_guts)
+ }}
+
+ where
+ dflags = hsc_dflags hsc_env
+ print_unqual = unQualInScope rdr_env
+
+ -- Desugarer warnings are SDocs; here we
+ -- add the info about whether or not to print unqualified
+ mk_warn :: (SrcLoc,SDoc) -> (SrcLoc, Pretty.Doc)
+ mk_warn (loc, sdoc) = addShortWarnLocLine loc print_unqual sdoc
+
+
+deSugarExpr :: HscEnv
+ -> Module -> GlobalRdrEnv -> TypeEnv
+ -> TypecheckedHsExpr
+ -> IO CoreExpr
+deSugarExpr hsc_env this_mod rdr_env type_env tc_expr
+ = do { showPass dflags "Desugar"
+ ; us <- mkSplitUniqSupply 'd'
+
+ -- Do desugaring
+ ; let { is_boot = emptyModuleEnv } -- Assume no hi-boot files when
+ -- doing stuff from the command line
+ ; (core_expr, ds_warns) <- initDs hsc_env this_mod type_env is_boot $
+ dsExpr tc_expr
+
+ -- Display any warnings
+ -- Note: if -Werror is used, we don't signal an error here.
+ ; doIfSet (not (isEmptyBag ds_warns))
+ (printErrs (pprBagOfWarnings (mapBag mk_warn ds_warns)))
+
+ -- Dump output
+ ; dumpIfSet_dyn dflags Opt_D_dump_ds "Desugared" (pprCoreExpr core_expr)
+
+ ; return core_expr
+ }
+ where
+ dflags = hsc_dflags hsc_env
+ print_unqual = unQualInScope rdr_env
+
+ mk_warn :: (SrcLoc,SDoc) -> (SrcLoc, Pretty.Doc)
+ mk_warn (loc,sdoc) = addShortWarnLocLine loc print_unqual sdoc
+
+
+dsProgram all_binds rules fo_decls
+ = dsMonoBinds auto_scc all_binds [] `thenDs` \ core_prs ->
+ dsForeigns fo_decls `thenDs` \ (ds_fords, foreign_binds) ->
+ let
+ ds_binds = [Rec (foreign_binds ++ core_prs)]
+ -- Notice that we put the whole lot in a big Rec, even the foreign binds
+ -- When compiling PrelFloat, which defines data Float = F# Float#
+ -- we want F# to be in scope in the foreign marshalling code!
+ -- You might think it doesn't matter, but the simplifier brings all top-level
+ -- things into the in-scope set before simplifying; so we get no unfolding for F#!
+
+ local_binders = mkVarSet (bindersOfBinds ds_binds)
+ in
+ mappM (dsRule local_binders) rules `thenDs` \ ds_rules ->
+ returnDs (ds_binds, ds_rules, ds_fords)
+ where
+ auto_scc | opt_SccProfilingOn = TopLevel
+ | otherwise = NoSccs
+
+ppr_ds_rules [] = empty
+ppr_ds_rules rules
+ = text "" $$ text "-------------- DESUGARED RULES -----------------" $$
+ pprIdRules rules
+\end{code}
+
+
+
+%************************************************************************
+%* *
+%* Desugaring transformation rules
+%* *
+%************************************************************************
+
+\begin{code}
+dsRule :: IdSet -> TypecheckedRuleDecl -> DsM (Id, CoreRule)
+dsRule in_scope (HsRule name act vars lhs rhs loc)
+ = putSrcLocDs loc $
+ ds_lhs all_vars lhs `thenDs` \ (fn, args) ->
+ dsExpr rhs `thenDs` \ core_rhs ->
+ returnDs (fn, Rule name act tpl_vars args core_rhs)
+ where
+ tpl_vars = [var | RuleBndr var <- vars]
+ all_vars = mkInScopeSet (in_scope `unionVarSet` mkVarSet tpl_vars)
+
+ds_lhs all_vars lhs
+ = let
+ (dict_binds, body) = case lhs of
+ (HsLet (MonoBind dict_binds _ _) body) -> (dict_binds, body)
+ other -> (EmptyMonoBinds, lhs)
+ in
+ ds_dict_binds dict_binds `thenDs` \ dict_binds' ->
+ dsExpr body `thenDs` \ body' ->
+
+ -- Substitute the dict bindings eagerly,
+ -- and take the body apart into a (f args) form
+ let
+ subst_env = mkSubstEnv [id | (id,rhs) <- dict_binds']
+ [ContEx subst_env rhs | (id,rhs) <- dict_binds']
+ -- Note recursion here... substitution won't terminate
+ -- if there is genuine recursion... which there isn't
+
+ subst = mkSubst all_vars subst_env
+ body'' = substExpr subst body'
+ in
+
+ -- Now unpack the resulting body
+ let
+ pair = case collectArgs body'' of
+ (Var fn, args) -> (fn, args)
+ other -> pprPanic "dsRule" (ppr lhs)
+ in
+ returnDs pair
- return ds_binds
+ds_dict_binds EmptyMonoBinds = returnDs []
+ds_dict_binds (AndMonoBinds b1 b2) = ds_dict_binds b1 `thenDs` \ env1 ->
+ ds_dict_binds b2 `thenDs` \ env2 ->
+ returnDs (env1 ++ env2)
+ds_dict_binds (VarMonoBind id rhs) = dsExpr rhs `thenDs` \ rhs' ->
+ returnDs [(id,rhs')]
\end{code}