%
-% (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 ( MonoBinds )
-import TcHsSyn ( TypecheckedMonoBinds )
+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 ( pprCoreBindings )
+import PprCore ( pprIdCoreRule, pprCoreExpr )
+import Subst ( substExpr, mkSubst, mkInScopeSet )
import DsMonad
-import DsBinds ( dsMonoBinds )
-import DsUtils
-
+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 BasicTypes ( Module )
-import CmdLineOpts ( opt_SccGroup, opt_SccProfilingOn )
-import CoreLift ( liftCoreBindings )
-import CoreLint ( lintCoreBindings )
-import Id ( nullIdEnv, GenId, Id )
-import ErrUtils ( dumpIfSet, doIfSet )
+import CoreLint ( showPass, endPass )
+import ErrUtils ( doIfSet, dumpIfSet_dyn, pprBagOfWarnings )
import Outputable
-import UniqSupply ( splitUniqSupply, UniqSupply )
+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
- -> Module -- module name
- -> TypecheckedMonoBinds
- -> IO [CoreBinding] -- output
-
-deSugar us mod_name all_binds
- = let
- (us1, us2) = splitUniqSupply us
+deSugar :: DynFlags
+ -> PersistentCompilerState -> HomeSymbolTable
+ -> Module -> PrintUnqualified
+ -> TcResults
+ -> IO (ModDetails, (SDoc, SDoc, [FAST_STRING], [CoreBndr]))
- module_and_group = (mod_name, grp_name)
- grp_name = case opt_SccGroup of
- Just xx -> _PK_ xx
- Nothing -> mod_name -- default: module name
+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'
- (core_prs, ds_warns) = initDs us1 nullIdEnv module_and_group
- (dsMonoBinds opt_SccProfilingOn all_binds [])
+ -- Do desugaring
+ ; let (ds_result, ds_warns) = initDs dflags us lookup mod_name
+ (dsProgram mod_name all_binds rules fo_decls)
- ds_binds = liftCoreBindings us2 [Rec core_prs]
- in
+ (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 (pprDsWarnings ds_warns)) >>
+ ; doIfSet (not (isEmptyBag ds_warns))
+ (printErrs unqual (pprBagOfWarnings ds_warns))
-- Lint result if necessary
- lintCoreBindings "Desugarer" False ds_binds >>
+ ; 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 opt_D_dump_ds "Desugared:"
- (pprCoreBindings ds_binds) >>
+ ; 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}
+
+
+%************************************************************************
+%* *
+%* Desugaring transformation rules
+%* *
+%************************************************************************
+
+\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
+ (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}
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