%
-% (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}
-#include "HsVersions.h"
-
-module Desugar ( deSugar, DsMatchContext, pprDsWarnings,
- DsWarnFlavour -- removed when compiling with 1.4
- ) where
+module Desugar ( deSugar, deSugarExpr ) where
-IMP_Ubiq(){-uitous-}
+#include "HsVersions.h"
-import HsSyn ( HsBinds, HsExpr )
-import TcHsSyn ( SYN_IE(TypecheckedHsBinds), SYN_IE(TypecheckedHsExpr) )
+import CmdLineOpts ( DynFlag(..), dopt, opt_SccProfilingOn )
+import HscTypes ( ModGuts(..), ModGuts, HscEnv(..), ExternalPackageState(..),
+ PersistentCompilerState(..), Dependencies(..),
+ lookupType, 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 Name ( isExported )
+import PprCore ( pprIdRules, pprCoreExpr )
+import Subst ( substExpr, mkSubst, mkInScopeSet )
import DsMonad
-import DsBinds ( dsBinds, dsInstBinds )
-import DsUtils
-
-import Bag ( unionBags )
-import CmdLineOpts ( opt_DoCoreLinting, opt_AutoSccsOnAllToplevs,
- opt_AutoSccsOnExportedToplevs, opt_SccGroup
- )
-import CostCentre ( IsCafCC(..), mkAutoCC )
-import CoreLift ( liftCoreBindings )
-import CoreLint ( lintCoreBindings )
-import Id ( nullIdEnv, mkIdEnv, idType, SYN_IE(DictVar), GenId )
-import PprStyle ( PprStyle(..) )
-import UniqSupply ( splitUniqSupply )
+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 )
+import Id ( Id )
+import NameEnv ( lookupNameEnv )
+import VarEnv
+import VarSet
+import Bag ( isEmptyBag, mapBag )
+import CoreLint ( showPass, endPass )
+import ErrUtils ( doIfSet, dumpIfSet_dyn, pprBagOfWarnings, addShortWarnLocLine )
+import Outputable
+import qualified Pretty
+import UniqSupply ( mkSplitUniqSupply )
+import SrcLoc ( SrcLoc )
+import FastString
+import DATA_IOREF ( readIORef )
\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
- -> FAST_STRING -- module name
-
- -> (TypecheckedHsBinds, -- input: recsel, class, instance, and value
- TypecheckedHsBinds, -- bindings; see "tcModule" (which produces
- TypecheckedHsBinds, -- them)
- TypecheckedHsBinds,
- [(Id, TypecheckedHsExpr)])
--- ToDo: handling of const_inst thingies is certainly WRONG ***************************
-
- -> ([CoreBinding], -- output
- DsWarnings) -- Shadowing complaints
-
-deSugar us mod_name (recsel_binds, clas_binds, inst_binds, val_binds, const_inst_pairs)
- = let
- (us0, us0a) = splitUniqSupply us
- (us1, us1a) = splitUniqSupply us0a
- (us2, us2a) = splitUniqSupply us1a
- (us3, us3a) = splitUniqSupply us2a
- (us4, us5) = splitUniqSupply us3a
-
-
- module_and_group = (mod_name, grp_name)
- grp_name = case opt_SccGroup of
- Just xx -> _PK_ xx
- Nothing -> mod_name -- default: module name
-
- ((core_const_prs, consts_pairs), shadows1)
- = initDs us0 nullIdEnv mod_name (dsInstBinds [] const_inst_pairs)
-
- consts_env = mkIdEnv consts_pairs
-
- (core_clas_binds, shadows2)
- = initDs us1 consts_env mod_name (dsBinds clas_binds)
- core_clas_prs = pairsFromCoreBinds core_clas_binds
-
- (core_inst_binds, shadows3)
- = initDs us2 consts_env mod_name (dsBinds inst_binds)
- core_inst_prs = pairsFromCoreBinds core_inst_binds
-
- (core_val_binds, shadows4)
- = initDs us3 consts_env mod_name (dsBinds val_binds)
- core_val_pairs = map (addAutoScc module_and_group) (pairsFromCoreBinds core_val_binds)
-
- (core_recsel_binds, shadows5)
- = initDs us4 consts_env mod_name (dsBinds recsel_binds)
- core_recsel_prs = pairsFromCoreBinds core_recsel_binds
-
- final_binds
- = if (null core_clas_prs && null core_inst_prs
- && null core_recsel_prs {-???dont know???-} && null core_const_prs) then
- -- we don't have to make the whole thing recursive
- core_clas_binds ++ core_val_binds
-
- else -- gotta make it recursive (sigh)
- [Rec (core_clas_prs ++ core_inst_prs
- ++ core_const_prs ++ core_val_pairs ++ core_recsel_prs)]
-
- lift_final_binds = liftCoreBindings us5 final_binds
-
- really_final_binds = if opt_DoCoreLinting
- then lintCoreBindings PprDebug "Desugarer" False lift_final_binds
- else lift_final_binds
-
- shadows = shadows1 `unionBags` shadows2 `unionBags`
- shadows3 `unionBags` shadows4 `unionBags` shadows5
+deSugar :: HscEnv -> PersistentCompilerState
+ -> TcGblEnv -> IO ModGuts
+
+deSugar hsc_env pcs
+ (TcGblEnv { tcg_mod = mod,
+ tcg_type_env = type_env,
+ tcg_usages = usage_var,
+ tcg_imports = imports,
+ tcg_exports = exports,
+ 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"
+ ; us <- mkSplitUniqSupply 'd'
+ ; usages <- readIORef usage_var
+
+ -- Do desugaring
+ ; let ((ds_binds, ds_rules, ds_fords), ds_warns)
+ = initDs dflags us lookup mod
+ (dsProgram binds rules fords)
+
+ warn_doc = pprBagOfWarnings (mapBag mk_warn ds_warns)
+
+ -- Display any warnings
+ ; doIfSet (not (isEmptyBag ds_warns))
+ (printErrs warn_doc)
+
+ -- Lint result if necessary
+ ; endPass dflags "Desugar" Opt_D_dump_ds ds_binds
+
+ -- Dump output
+ ; doIfSet (dopt Opt_D_dump_ds dflags)
+ (printDump (ppr_ds_rules ds_rules))
+
+ ; 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 = mkUsageInfo hsc_env eps imports 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 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
+
+ -- The lookup function passed to initDs is used for well-known Ids,
+ -- such as fold, build, cons etc, so the chances are
+ -- it'll be found in the package symbol table. That's
+ -- why we don't merge all these tables
+ eps = pcs_EPS pcs
+ pte = eps_PTE eps
+ hpt = hsc_HPT hsc_env
+ lookup n = case lookupType hpt pte n of {
+ Just v -> v ;
+ other ->
+ case lookupNameEnv type_env n of
+ Just v -> v ;
+ other -> pprPanic "Desugar: lookup:" (ppr n)
+ }
+
+deSugarExpr :: HscEnv
+ -> PersistentCompilerState
+ -> Module -> PrintUnqualified
+ -> TypecheckedHsExpr
+ -> IO CoreExpr
+deSugarExpr hsc_env pcs mod_name unqual tc_expr
+ = do { showPass dflags "Desugar"
+ ; us <- mkSplitUniqSupply 'd'
+
+ -- Do desugaring
+ ; let (core_expr, ds_warns) = initDs dflags us lookup mod_name (dsExpr tc_expr)
+ warn_doc = pprBagOfWarnings (mapBag mk_warn ds_warns)
+ mk_warn :: (SrcLoc,SDoc) -> (SrcLoc, Pretty.Doc)
+ mk_warn (loc,sdoc) = addShortWarnLocLine loc unqual sdoc
+
+ -- Display any warnings
+ ; doIfSet (not (isEmptyBag ds_warns))
+ (printErrs warn_doc)
+
+ -- Dump output
+ ; dumpIfSet_dyn dflags Opt_D_dump_ds "Desugared" (pprCoreExpr core_expr)
+
+ ; return core_expr
+ }
+ where
+ dflags = hsc_dflags hsc_env
+ hpt = hsc_HPT hsc_env
+ pte = eps_PTE (pcs_EPS pcs)
+ lookup n = case lookupType hpt pte n of
+ Just v -> v
+ other -> pprPanic "Desugar: lookup:" (ppr n)
+
+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
- (really_final_binds, shadows)
+ mapDs (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}
+
%************************************************************************
%* *
-\subsection[addAutoScc]{Adding automatic sccs}
+%* Desugaring transformation rules
%* *
%************************************************************************
\begin{code}
-addAutoScc :: (FAST_STRING, FAST_STRING) -- Module and group
- -> (Id, CoreExpr)
- -> (Id,CoreExpr)
-
-addAutoScc (mod, grp) pair@(bndr, core_expr)
- | worthSCC core_expr &&
- (opt_AutoSccsOnAllToplevs ||
- (isExported bndr && opt_AutoSccsOnExportedToplevs))
- = (bndr, SCC (mkAutoCC bndr mod grp IsNotCafCC) core_expr)
-
- | otherwise
- = pair
-
-worthSCC (SCC _ _) = False
-worthSCC (Con _ _) = False
-worthSCC core_expr = True
+dsRule :: IdSet -> TypecheckedRuleDecl -> DsM (Id, CoreRule)
+dsRule in_scope (IfaceRuleOut fun rule) -- Built-in rules come this way
+ = returnDs (fun, rule)
+
+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
+
+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}
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