%
+% (c) The University of Glasgow 2006
% (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
%
-\section[Desugar]{@deSugar@: the main function}
+
+The Desugarer: turning HsSyn into Core.
\begin{code}
module Desugar ( deSugar, deSugarExpr ) where
#include "HsVersions.h"
-import DynFlags ( DynFlag(..), DynFlags(..), dopt, GhcMode(..) )
-import StaticFlags ( opt_SccProfilingOn )
-import DriverPhases ( isHsBoot )
-import HscTypes ( ModGuts(..), HscEnv(..),
- Dependencies(..), ForeignStubs(..), TypeEnv, IsBootInterface )
-import HsSyn ( RuleDecl(..), RuleBndr(..), LHsExpr, LRuleDecl )
-import TcRnTypes ( TcGblEnv(..), ImportAvails(..) )
-import MkIface ( mkUsageInfo )
-import Id ( Id, setIdExported, idName )
-import Name ( Name, isExternalName, nameIsLocalOrFrom, nameOccName )
+import DynFlags
+import StaticFlags
+import HscTypes
+import HsSyn
+import TcRnTypes
+import MkIface
+import Id
+import Name
import CoreSyn
-import PprCore ( pprRules, pprCoreExpr )
+import OccurAnal
+import PprCore
import DsMonad
-import DsExpr ( dsLExpr )
-import DsBinds ( dsTopLHsBinds, decomposeRuleLhs, AutoScc(..) )
-import DsForeign ( dsForeigns )
+import DsExpr
+import DsBinds
+import DsForeign
import DsExpr () -- Forces DsExpr to be compiled; DsBinds only
-- depends on DsExpr.hi-boot.
import Module
-import UniqFM ( eltsUFM, delFromUFM )
-import PackageConfig ( thPackageId )
-import RdrName ( GlobalRdrEnv )
+import UniqFM
+import PackageConfig
+import RdrName
import NameSet
import VarSet
-import Bag ( Bag, isEmptyBag, emptyBag )
-import Rules ( roughTopNames )
-import CoreLint ( showPass, endPass )
-import CoreFVs ( ruleRhsFreeVars, exprsFreeNames )
-import ErrUtils ( doIfSet, dumpIfSet_dyn, printBagOfWarnings,
- errorsFound, WarnMsg )
-import ListSetOps ( insertList )
+import Rules
+import CoreLint
+import CoreFVs
+import ErrUtils
+import ListSetOps
import Outputable
-import UniqSupply ( mkSplitUniqSupply )
-import SrcLoc ( Located(..) )
-import DATA_IOREF ( readIORef )
-import Maybes ( catMaybes )
+import SrcLoc
+import Maybes
import FastString
-import Util ( sortLe )
+import Util
+import Coverage
+import IOEnv
+import Data.IORef
\end{code}
%************************************************************************
%************************************************************************
\begin{code}
-deSugar :: HscEnv -> TcGblEnv -> IO (Bag WarnMsg, Maybe ModGuts)
+deSugar :: HscEnv -> ModLocation -> TcGblEnv -> IO (Maybe ModGuts)
-- Can modify PCS by faulting in more declarations
deSugar hsc_env
- tcg_env@(TcGblEnv { tcg_mod = mod,
- tcg_src = hsc_src,
- tcg_type_env = type_env,
- tcg_imports = imports,
- tcg_exports = exports,
- tcg_dus = dus,
- tcg_inst_uses = dfun_uses_var,
- tcg_th_used = th_var,
- tcg_keep = keep_var,
- tcg_rdr_env = rdr_env,
- tcg_fix_env = fix_env,
- tcg_deprecs = deprecs,
- tcg_binds = binds,
- tcg_fords = fords,
- tcg_rules = rules,
- tcg_insts = insts })
- = do { showPass dflags "Desugar"
+ mod_loc
+ tcg_env@(TcGblEnv { tcg_mod = mod,
+ tcg_src = hsc_src,
+ tcg_type_env = type_env,
+ tcg_imports = imports,
+ tcg_exports = exports,
+ tcg_dus = dus,
+ tcg_inst_uses = dfun_uses_var,
+ tcg_th_used = th_var,
+ tcg_keep = keep_var,
+ tcg_rdr_env = rdr_env,
+ tcg_fix_env = fix_env,
+ tcg_fam_inst_env = fam_inst_env,
+ tcg_deprecs = deprecs,
+ tcg_binds = binds,
+ tcg_fords = fords,
+ tcg_rules = rules,
+ tcg_insts = insts,
+ tcg_fam_insts = fam_insts })
+
+ = do { let dflags = hsc_dflags hsc_env
+ ; showPass dflags "Desugar"
-- Desugar the program
- ; ((all_prs, ds_rules, ds_fords), warns)
- <- case ghcMode (hsc_dflags hsc_env) of
- JustTypecheck -> return (([], [], NoStubs), emptyBag)
- _ -> initDs hsc_env mod rdr_env type_env $ do
- { core_prs <- dsTopLHsBinds auto_scc binds
+ ; let export_set = availsToNameSet exports
+ ; let auto_scc = mkAutoScc mod export_set
+ ; let target = hscTarget dflags
+ ; mb_res <- case target of
+ HscNothing -> return (Just ([], [], NoStubs, noHpcInfo, emptyModBreaks))
+ _ -> do (binds_cvr,ds_hpc_info, modBreaks)
+ <- if opt_Hpc || target == HscInterpreted
+ then addCoverageTicksToBinds dflags mod mod_loc binds
+ else return (binds, noHpcInfo, emptyModBreaks)
+ initDs hsc_env mod rdr_env type_env $ do
+ { core_prs <- dsTopLHsBinds auto_scc binds_cvr
; (ds_fords, foreign_prs) <- dsForeigns fords
; let all_prs = foreign_prs ++ core_prs
local_bndrs = mkVarSet (map fst all_prs)
; ds_rules <- mappM (dsRule mod local_bndrs) rules
- ; return (all_prs, catMaybes ds_rules, ds_fords)
+ ; return (all_prs, catMaybes ds_rules, ds_fords, ds_hpc_info, modBreaks)
}
-
- -- If warnings are considered errors, leave.
- ; if errorsFound dflags (warns, emptyBag)
- then return (warns, Nothing)
- else do
+ ; case mb_res of {
+ Nothing -> return Nothing ;
+ Just (all_prs, ds_rules, ds_fords,ds_hpc_info, modBreaks) -> do
{ -- Add export flags to bindings
keep_alive <- readIORef keep_var
- ; let final_prs = addExportFlags ghci_mode exports keep_alive
- all_prs ds_rules
+ ; let final_prs = addExportFlags target export_set
+ keep_alive 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#
dir_imp_mods = imp_mods imports
- ; showPass dflags "Desugar 3"
-
; usages <- mkUsageInfo hsc_env dir_imp_mods dep_mods used_names
- ; showPass dflags "Desugar 4"
-
; let
-- Modules don't compare lexicographically usually,
-- but we want them to do so here.
le_dep_mod :: (ModuleName, IsBootInterface) -> (ModuleName, IsBootInterface) -> Bool
le_dep_mod (m1,_) (m2,_) = moduleNameFS m1 <= moduleNameFS m2
- deps = Deps { dep_mods = sortLe le_dep_mod dep_mods,
- dep_pkgs = sortLe (<=) pkgs,
- dep_orphs = sortLe le_mod (imp_orphs imports) }
+ deps = Deps { dep_mods = sortLe le_dep_mod dep_mods,
+ dep_pkgs = sortLe (<=) pkgs,
+ dep_orphs = sortLe le_mod (imp_orphs imports),
+ dep_finsts = sortLe le_mod (imp_finsts imports) }
-- sort to get into canonical order
mod_guts = ModGuts {
- mg_module = mod,
- mg_boot = isHsBoot hsc_src,
- mg_exports = exports,
- mg_deps = deps,
- mg_usages = usages,
- mg_dir_imps = [m | (m,_,_) <- moduleEnvElts dir_imp_mods],
- 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 (warns, Just mod_guts)
- }}
+ mg_module = mod,
+ mg_boot = isHsBoot hsc_src,
+ mg_exports = exports,
+ mg_deps = deps,
+ mg_usages = usages,
+ mg_dir_imps = [m | (m,_,_) <- moduleEnvElts dir_imp_mods],
+ mg_rdr_env = rdr_env,
+ mg_fix_env = fix_env,
+ mg_deprecs = deprecs,
+ mg_types = type_env,
+ mg_insts = insts,
+ mg_fam_insts = fam_insts,
+ mg_fam_inst_env = fam_inst_env,
+ mg_rules = ds_rules,
+ mg_binds = ds_binds,
+ mg_foreign = ds_fords,
+ mg_hpc_info = ds_hpc_info,
+ mg_modBreaks = modBreaks }
+ ; return (Just mod_guts)
+ }}}
+
+mkAutoScc :: Module -> NameSet -> AutoScc
+mkAutoScc mod exports
+ | not opt_SccProfilingOn -- No profiling
+ = NoSccs
+ | opt_AutoSccsOnAllToplevs -- Add auto-scc on all top-level things
+ = AddSccs mod (\id -> True)
+ | opt_AutoSccsOnExportedToplevs -- Only on exported things
+ = AddSccs mod (\id -> idName id `elemNameSet` exports)
+ | otherwise
+ = NoSccs
- where
- dflags = hsc_dflags hsc_env
- ghci_mode = ghcMode (hsc_dflags hsc_env)
- auto_scc | opt_SccProfilingOn = TopLevel
- | otherwise = NoSccs
deSugarExpr :: HscEnv
-> Module -> GlobalRdrEnv -> TypeEnv
-> LHsExpr Id
- -> IO CoreExpr
+ -> IO (Maybe CoreExpr)
+-- Prints its own errors; returns Nothing if error occurred
+
deSugarExpr hsc_env this_mod rdr_env type_env tc_expr
- = do { showPass dflags "Desugar"
- ; us <- mkSplitUniqSupply 'd'
+ = do { let dflags = hsc_dflags hsc_env
+ ; showPass dflags "Desugar"
-- Do desugaring
- ; (core_expr, ds_warns) <- initDs hsc_env this_mod rdr_env type_env $
- dsLExpr tc_expr
+ ; mb_core_expr <- initDs hsc_env this_mod rdr_env type_env $
+ dsLExpr tc_expr
- -- Display any warnings
- -- Note: if -Werror is used, we don't signal an error here.
- ; doIfSet (not (isEmptyBag ds_warns))
- (printBagOfWarnings dflags ds_warns)
+ ; case mb_core_expr of {
+ Nothing -> return Nothing ;
+ Just expr -> do {
- -- Dump output
- ; dumpIfSet_dyn dflags Opt_D_dump_ds "Desugared" (pprCoreExpr core_expr)
-
- ; return core_expr
- }
- where
- dflags = hsc_dflags hsc_env
+ -- Dump output
+ dumpIfSet_dyn dflags Opt_D_dump_ds "Desugared" (pprCoreExpr expr)
+ ; return (Just expr) } } }
-- addExportFlags
-- Set the no-discard flag if either
-- 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 prs rules
+addExportFlags target exports keep_alive prs rules
= [(add_export bndr, rhs) | (bndr,rhs) <- prs]
where
add_export bndr
-- 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
+ is_exported | target == HscInterpreted = isExternalName
| otherwise = (`elemNameSet` exports)
ppr_ds_rules [] = empty
dsRule :: Module -> IdSet -> LRuleDecl Id -> DsM (Maybe CoreRule)
dsRule mod in_scope (L loc (HsRule name act vars lhs tv_lhs rhs fv_rhs))
= putSrcSpanDs loc $
- do { let bndrs = [var | RuleBndr (L _ var) <- vars]
+ do { let bndrs = [var | RuleBndr (L _ var) <- vars]
; lhs' <- dsLExpr lhs
; rhs' <- dsLExpr rhs
- ; case decomposeRuleLhs bndrs lhs' of {
- Nothing -> do { dsWarn msg; return Nothing } ;
- Just (bndrs', fn_id, args) -> do
+ ; case decomposeRuleLhs (occurAnalyseExpr lhs') of {
+ Nothing -> do { warnDs msg; return Nothing } ;
+ Just (fn_id, args) -> do
-- Substitute the dict bindings eagerly,
-- and take the body apart into a (f args) form
- { let local_rule = nameIsLocalOrFrom mod fn_name
- -- NB we can't use isLocalId in the orphan test,
- -- because isLocalId isn't true of class methods
+ { let local_rule = isLocalId fn_id
+ -- NB: isLocalId is False of implicit Ids. This is good becuase
+ -- we don't want to attach rules to the bindings of implicit Ids,
+ -- because they don't show up in the bindings until just before code gen
fn_name = idName fn_id
- lhs_names = fn_name : nameSetToList (exprsFreeNames args)
- -- No need to delete bndrs, because
- -- exprsFreeNames finds only External names
- orph = case filter (nameIsLocalOrFrom mod) lhs_names of
- (n:ns) -> Just (nameOccName n)
- [] -> Nothing
rule = Rule { ru_name = name, ru_fn = fn_name, ru_act = act,
- ru_bndrs = bndrs', ru_args = args, ru_rhs = rhs',
+ ru_bndrs = bndrs, ru_args = args, ru_rhs = rhs',
ru_rough = roughTopNames args,
- ru_local = local_rule, ru_orph = orph }
+ ru_local = local_rule }
; return (Just rule)
} } }
where