\section[Desugar]{@deSugar@: the main function}
\begin{code}
-module Desugar ( deSugar ) where
+module Desugar ( deSugar, deSugarExpr ) where
#include "HsVersions.h"
-import CmdLineOpts ( opt_D_dump_ds )
-import HsSyn ( MonoBinds, RuleDecl(..), RuleBndr(..), HsExpr(..), HsBinds(..), MonoBinds(..) )
-import HsCore ( UfRuleBody(..) )
-import TcHsSyn ( TypecheckedMonoBinds, TypecheckedForeignDecl, TypecheckedRuleDecl )
-import TcModule ( TcResults(..) )
+import CmdLineOpts ( DynFlag(..), dopt, opt_SccProfilingOn )
+import HscTypes ( ModGuts(..), ModGuts, HscEnv(..), GhciMode(..),
+ Dependencies(..), TypeEnv,
+ unQualInScope, availsToNameSet )
+import HsSyn ( RuleDecl(..), RuleBndr(..), HsExpr(..), LHsExpr,
+ HsBindGroup(..), LRuleDecl, HsBind(..) )
+import TcRnTypes ( TcGblEnv(..), ImportAvails(..) )
+import MkIface ( mkUsageInfo )
+import Id ( Id, setIdLocalExported, idName )
+import Name ( Name, isExternalName )
import CoreSyn
-import Rules ( ProtoCoreRule(..), pprProtoCoreRule )
-import Subst ( substExpr, mkSubst )
+import PprCore ( pprIdRules, pprCoreExpr )
+import Subst ( substExpr, mkSubst, mkInScopeSet )
import DsMonad
-import DsExpr ( dsExpr )
-import DsBinds ( dsMonoBinds, AutoScc(..) )
+import DsExpr ( dsLExpr )
+import DsBinds ( dsHsBinds, AutoScc(..) )
import DsForeign ( dsForeigns )
-import DsUtils
import DsExpr () -- Forces DsExpr to be compiled; DsBinds only
-- depends on DsExpr.hi-boot.
-import Module ( Module, moduleString )
+import Module ( Module, moduleEnvElts, emptyModuleEnv )
import Id ( Id )
-import Name ( isLocallyDefined )
+import RdrName ( GlobalRdrEnv )
+import NameSet
import VarEnv
import VarSet
-import Bag ( isEmptyBag, unionBags )
-import CmdLineOpts ( opt_SccGroup, opt_SccProfilingOn )
-import CoreLint ( beginPass, endPass )
-import ErrUtils ( doIfSet, pprBagOfWarnings )
+import Bag ( isEmptyBag, mapBag, emptyBag, bagToList )
+import CoreLint ( showPass, endPass )
+import CoreFVs ( ruleRhsFreeVars )
+import ErrUtils ( doIfSet, dumpIfSet_dyn, pprBagOfWarnings,
+ mkWarnMsg, errorsFound, WarnMsg )
import Outputable
-import UniqSupply ( splitUniqSupply, UniqSupply )
+import UniqSupply ( mkSplitUniqSupply )
+import SrcLoc ( Located(..), SrcSpan, unLoc )
+import DATA_IOREF ( readIORef )
+import FastString
\end{code}
%************************************************************************
%* *
%************************************************************************
-The only trick here is to get the @DsMonad@ stuff off to a good
-start.
-
\begin{code}
-deSugar :: Module
- -> UniqSupply
- -> TcResults
- -> IO ([CoreBind], [ProtoCoreRule], SDoc, SDoc)
-
-deSugar mod_name us (TcResults {tc_env = global_val_env,
- tc_binds = all_binds,
- tc_rules = rules,
- tc_fords = fo_decls})
- = do
- beginPass "Desugar"
+deSugar :: HscEnv -> TcGblEnv -> IO (Maybe ModGuts)
+-- Can modify PCS by faulting in more declarations
+
+deSugar hsc_env
+ tcg_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 })
+ = do { showPass dflags "Desugar"
+
-- Do desugaring
- let (result, ds_warns) = initDs us global_val_env module_and_group
- (dsProgram mod_name all_binds rules fo_decls)
- (ds_binds, ds_rules, _, _) = result
+ ; let { is_boot = imp_dep_mods imports }
+ ; (results, warnings) <- initDs hsc_env mod type_env is_boot $
+ dsProgram ghci_mode tcg_env
+
+ ; let { (ds_binds, ds_rules, ds_fords) = results
+ ; warns = mapBag mk_warn warnings
+ ; warn_doc = pprBagOfWarnings warns }
+
+ -- Display any warnings
+ ; 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
+ { endPass dflags "Desugar" Opt_D_dump_ds ds_binds
+
+ -- Dump output
+ ; 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 `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
+ ghci_mode = hsc_mode 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 :: (SrcSpan,SDoc) -> WarnMsg
+ mk_warn (loc, sdoc) = mkWarnMsg loc print_unqual sdoc
+
+
+deSugarExpr :: HscEnv
+ -> Module -> GlobalRdrEnv -> TypeEnv
+ -> LHsExpr Id
+ -> IO CoreExpr
+deSugarExpr hsc_env this_mod rdr_env type_env tc_expr
+ = do { showPass dflags "Desugar"
+ ; us <- mkSplitUniqSupply 'd'
- -- Display any warnings
- doIfSet (not (isEmptyBag ds_warns))
- (printErrs (pprBagOfWarnings ds_warns))
+ -- 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 $
+ dsLExpr tc_expr
- -- Lint result if necessary
- endPass "Desugar" opt_D_dump_ds ds_binds
+ -- 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)))
- doIfSet opt_D_dump_ds (printDump (ppr_ds_rules ds_rules))
+ -- Dump output
+ ; dumpIfSet_dyn dflags Opt_D_dump_ds "Desugared" (pprCoreExpr core_expr)
- return result
+ ; return core_expr
+ }
where
- module_and_group = (mod_name, grp_name)
- grp_name = case opt_SccGroup of
- Just xx -> _PK_ xx
- Nothing -> _PK_ (moduleString mod_name) -- default: module name
-
-dsProgram mod_name all_binds rules fo_decls
- = dsMonoBinds auto_scc all_binds [] `thenDs` \ core_prs ->
- dsForeigns mod_name fo_decls `thenDs` \ (fi_binds, fe_binds, h_code, c_code) ->
- mapDs dsRule rules `thenDs` \ rules' ->
- let
- ds_binds = fi_binds ++ [Rec core_prs] ++ fe_binds
+ dflags = hsc_dflags hsc_env
+ print_unqual = unQualInScope rdr_env
+
+ mk_warn :: (SrcSpan,SDoc) -> WarnMsg
+ mk_warn (loc,sdoc) = mkWarnMsg loc print_unqual sdoc
+
+
+dsProgram ghci_mode (TcGblEnv { tcg_exports = exports,
+ tcg_keep = keep_alive,
+ tcg_binds = binds,
+ tcg_fords = fords,
+ tcg_rules = rules })
+ = dsHsBinds auto_scc binds [] `thenDs` \ core_prs ->
+ dsForeigns fords `thenDs` \ (ds_fords, foreign_prs) ->
+ let
+ all_prs = foreign_prs ++ core_prs
+ local_bndrs = mkVarSet (map fst all_prs)
+ in
+ mappM (dsRule local_bndrs) rules `thenDs` \ ds_rules ->
+ let
+ final_prs = addExportFlags ghci_mode exports keep_alive
+ local_bndrs all_prs ds_rules
+ ds_binds = [Rec final_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#!
in
- returnDs (ds_binds, rules', h_code, c_code)
+ returnDs (ds_binds, ds_rules, ds_fords)
where
auto_scc | opt_SccProfilingOn = TopLevel
| otherwise = NoSccs
+-- addExportFlags
+-- Set the no-discard flag if either
+-- a) the Id is exported
+-- b) it's mentioned in the RHS of an orphan rule
+-- c) it's in the keep-alive set
+--
+-- It means that the binding won't be discarded EVEN if the binding
+-- ends up being trivial (v = w) -- the simplifier would usually just
+-- substitute w for v throughout, but we don't apply the substitution to
+-- the rules (maybe we should?), so this substitution would make the rule
+-- bogus.
+
+-- You might wonder why exported Ids aren't already marked as such;
+-- it's just because the type checker is rather busy already and
+-- I didn't want to pass in yet another mapping.
+
+addExportFlags ghci_mode exports keep_alive bndrs prs rules
+ = [(add_export bndr, rhs) | (bndr,rhs) <- prs]
+ where
+ add_export bndr | dont_discard bndr = setIdLocalExported bndr
+ | otherwise = bndr
+
+ orph_rhs_fvs = unionVarSets [ ruleRhsFreeVars rule
+ | (id, rule) <- rules,
+ not (id `elemVarSet` bndrs) ]
+ -- An orphan rule must keep alive the free vars
+ -- of its right-hand side.
+ -- Non-orphan rules are attached to the Id (bndr_with_rules above)
+ -- and that keeps the rhs free vars alive
+
+ dont_discard bndr = is_exported name
+ || name `elemNameSet` keep_alive
+ || bndr `elemVarSet` orph_rhs_fvs
+ where
+ name = idName bndr
+
+ -- In interactive mode, we don't want to discard any top-level
+ -- entities at all (eg. do not inline them away during
+ -- simplification), and retain them all in the TypeEnv so they are
+ -- available from the command line.
+ --
+ -- isExternalName separates the user-defined top-level names from those
+ -- introduced by the type checker.
+ is_exported :: Name -> Bool
+ is_exported | ghci_mode == Interactive = isExternalName
+ | otherwise = (`elemNameSet` exports)
+
ppr_ds_rules [] = empty
ppr_ds_rules rules
= text "" $$ text "-------------- DESUGARED RULES -----------------" $$
- vcat (map pprProtoCoreRule rules)
+ pprIdRules rules
\end{code}
+
%************************************************************************
%* *
%* Desugaring transformation rules
%************************************************************************
\begin{code}
-dsRule :: TypecheckedRuleDecl -> DsM ProtoCoreRule
-dsRule (IfaceRuleDecl fn (CoreRuleBody name all_vars args rhs) loc)
- = returnDs (ProtoCoreRule False {- non-local -} fn
- (Rule name all_vars args rhs))
-
-dsRule (RuleDecl name sig_tvs vars lhs rhs loc)
- = putSrcLocDs loc $
+dsRule :: IdSet -> LRuleDecl Id -> DsM (Id, CoreRule)
+dsRule in_scope (L loc (HsRule name act vars lhs rhs))
+ = putSrcSpanDs loc $
ds_lhs all_vars lhs `thenDs` \ (fn, args) ->
- dsExpr rhs `thenDs` \ core_rhs ->
- returnDs (ProtoCoreRule True {- local -} fn
- (Rule name all_vars args core_rhs))
+ dsLExpr rhs `thenDs` \ core_rhs ->
+ returnDs (fn, Rule name act tpl_vars args core_rhs)
where
- all_vars = sig_tvs ++ [var | RuleBndr var <- vars]
+ tpl_vars = [var | RuleBndr (L _ var) <- vars]
+ all_vars = mkInScopeSet (extendVarSetList in_scope 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)
+ (dict_binds, body) =
+ case unLoc lhs of
+ (HsLet [HsBindGroup dict_binds _ _] body) -> (dict_binds, body)
+ other -> (emptyBag, lhs)
in
- ds_dict_binds dict_binds `thenDs` \ dict_binds' ->
- dsExpr body `thenDs` \ body' ->
+ mappM ds_dict_bind (bagToList dict_binds) `thenDs` \ dict_binds' ->
+ dsLExpr body `thenDs` \ body' ->
-- Substitute the dict bindings eagerly,
-- and take the body apart into a (f args) form
-- Note recursion here... substitution won't terminate
-- if there is genuine recursion... which there isn't
- subst = mkSubst (mkVarSet all_vars) subst_env
+ subst = mkSubst all_vars subst_env
body'' = substExpr subst body'
in
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')]
+ds_dict_bind (L _ (VarBind id rhs)) =
+ dsLExpr rhs `thenDs` \ rhs' ->
+ returnDs (id,rhs')
\end{code}
projects / ghc-hetmet.git / blobdiff