%
-% (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 ) where
+module Desugar ( deSugar, deSugarExpr ) where
-import Ubiq{-uitous-}
+#include "HsVersions.h"
-import HsSyn ( HsBinds, HsExpr )
-import TcHsSyn ( TypecheckedHsBinds(..), TypecheckedHsExpr(..) )
+import CmdLineOpts ( DynFlags, DynFlag(..), dopt, opt_SccProfilingOn )
+import HscTypes ( ModDetails(..) )
+import HsSyn ( MonoBinds, RuleDecl(..), RuleBndr(..),
+ HsExpr(..), HsBinds(..), MonoBinds(..) )
+import TcHsSyn ( TypecheckedRuleDecl, TypecheckedHsExpr )
+import TcModule ( TcResults(..) )
+import Id ( Id )
import CoreSyn
-
+import PprCore ( pprIdCoreRule, pprCoreExpr )
+import Subst ( substExpr, mkSubst, mkInScopeSet )
import DsMonad
-import DsBinds ( dsBinds, dsInstBinds )
-import DsUtils
-
-import Bag ( unionBags )
-import CmdLineOpts ( opt_DoCoreLinting )
-import CoreLift ( liftCoreBindings )
-import CoreLint ( lintCoreBindings )
-import Id ( nullIdEnv, mkIdEnv )
-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 )
+import Id ( Id )
+import NameEnv ( lookupNameEnv )
+import VarEnv
+import VarSet
+import Bag ( isEmptyBag )
+import CoreLint ( showPass, endPass )
+import ErrUtils ( doIfSet, dumpIfSet_dyn, pprBagOfWarnings )
+import Outputable
+import UniqSupply ( mkSplitUniqSupply )
+import HscTypes ( HomeSymbolTable, PersistentCompilerState(..), TyThing(..), lookupType, )
\end{code}
+%************************************************************************
+%* *
+%* The main function: deSugar
+%* *
+%************************************************************************
+
The only trick here is to get the @DsMonad@ stuff off to a good
start.
\begin{code}
-deSugar :: UniqSupply -- name supply
- -> FAST_STRING -- module name
+deSugar :: DynFlags
+ -> PersistentCompilerState -> HomeSymbolTable
+ -> Module -> PrintUnqualified
+ -> TcResults
+ -> IO (ModDetails, (SDoc, SDoc, [FAST_STRING], [CoreBndr]))
+
+deSugar dflags pcs hst mod_name unqual
+ (TcResults {tc_env = type_env,
+ tc_binds = all_binds,
+ tc_insts = insts,
+ tc_rules = rules,
+ tc_fords = fo_decls})
+ = do { showPass dflags "Desugar"
+ ; us <- mkSplitUniqSupply 'd'
+
+ -- Do desugaring
+ ; let (ds_result, ds_warns) = initDs dflags us lookup mod_name
+ (dsProgram mod_name all_binds rules fo_decls)
+
+ (ds_binds, ds_rules, foreign_stuff) = ds_result
+
+ mod_details = ModDetails { md_types = type_env,
+ md_insts = insts,
+ md_rules = ds_rules,
+ md_binds = ds_binds }
+
+ -- Display any warnings
+ ; doIfSet (not (isEmptyBag ds_warns))
+ (printErrs unqual (pprBagOfWarnings ds_warns))
+
+ -- 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))
+
+ ; return (mod_details, foreign_stuff)
+ }
+
+ where
+ -- 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
+ pte = pcs_PTE pcs
+ lookup n = case lookupType hst pte n of {
+ Just (AnId v) -> v ;
+ other ->
+ case lookupNameEnv type_env n of
+ Just (AnId v) -> v ;
+ other -> pprPanic "Desugar: lookup:" (ppr n)
+ }
+
+deSugarExpr :: DynFlags
+ -> PersistentCompilerState -> HomeSymbolTable
+ -> Module -> PrintUnqualified
+ -> TypecheckedHsExpr
+ -> IO CoreExpr
+deSugarExpr dflags pcs hst 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)
+
+ -- Display any warnings
+ ; doIfSet (not (isEmptyBag ds_warns))
+ (printErrs unqual (pprBagOfWarnings ds_warns))
+
+ -- Dump output
+ ; dumpIfSet_dyn dflags Opt_D_dump_ds "Desugared" (pprCoreExpr core_expr)
+
+ ; return core_expr
+ }
+ where
+ pte = pcs_PTE pcs
+ lookup n = case lookupType hst pte n of
+ Just (AnId v) -> v
+ other -> pprPanic "Desugar: lookup:" (ppr n)
+
+dsProgram mod_name all_binds rules fo_decls
+ = dsMonoBinds auto_scc all_binds [] `thenDs` \ core_prs ->
+ dsForeigns mod_name fo_decls `thenDs` \ (fe_binders, foreign_binds, h_code, c_code, headers) ->
+ 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
+ mapDs (dsRule local_binders) rules `thenDs` \ rules' ->
+ returnDs (ds_binds, rules', (h_code, c_code, headers, fe_binders))
+ where
+ auto_scc | opt_SccProfilingOn = TopLevel
+ | otherwise = NoSccs
+
+ppr_ds_rules [] = empty
+ppr_ds_rules rules
+ = text "" $$ text "-------------- DESUGARED RULES -----------------" $$
+ vcat (map pprIdCoreRule rules)
+\end{code}
- -> (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
- Bag DsMatchContext) -- Shadowing complaints
+%************************************************************************
+%* *
+%* Desugaring transformation rules
+%* *
+%************************************************************************
-deSugar us mod_name (recsel_binds, clas_binds, inst_binds, val_binds, const_inst_pairs)
+\begin{code}
+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
- (us0, us0a) = splitUniqSupply us
- (us1, us1a) = splitUniqSupply us0a
- (us2, us2a) = splitUniqSupply us1a
- (us3, us3a) = splitUniqSupply us2a
- (us4, us5) = splitUniqSupply us3a
-
- ((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 = 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
+ (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
- (really_final_binds, shadows)
+ 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}
projects / ghc-hetmet.git / blobdiff