ghc-9.0.2: GHC/HsToCore/Foreign/Decl.hs
{-
(c) The University of Glasgow 2006
(c) The AQUA Project, Glasgow University, 1998
Desugaring foreign declarations (see also GHC.HsToCore.Foreign.Call).
-}
{-# LANGUAGE CPP #-}
{-# LANGUAGE FlexibleContexts #-}
{-# LANGUAGE TypeFamilies #-}
{-# LANGUAGE ViewPatterns #-}
{-# OPTIONS_GHC -Wno-incomplete-uni-patterns #-}
module GHC.HsToCore.Foreign.Decl ( dsForeigns ) where
#include "HsVersions.h"
import GHC.Prelude
import GHC.Tc.Utils.Monad -- temp
import GHC.Core
import GHC.HsToCore.Foreign.Call
import GHC.HsToCore.Monad
import GHC.Hs
import GHC.Core.DataCon
import GHC.Core.Unfold
import GHC.Types.Id
import GHC.Types.Literal
import GHC.Unit.Module
import GHC.Types.Name
import GHC.Core.Type
import GHC.Types.RepType
import GHC.Core.TyCon
import GHC.Core.Coercion
import GHC.Core.Multiplicity
import GHC.Tc.Utils.Env
import GHC.Tc.Utils.TcType
import GHC.Cmm.Expr
import GHC.Cmm.Utils
import GHC.Driver.Types
import GHC.Types.ForeignCall
import GHC.Builtin.Types
import GHC.Builtin.Types.Prim
import GHC.Builtin.Names
import GHC.Types.Basic
import GHC.Types.SrcLoc
import GHC.Utils.Outputable
import GHC.Data.FastString
import GHC.Driver.Session
import GHC.Platform
import GHC.Data.OrdList
import GHC.Utils.Misc
import GHC.Driver.Hooks
import GHC.Utils.Encoding
import Data.Maybe
import Data.List
{-
Desugaring of @foreign@ declarations is naturally split up into
parts, an @import@ and an @export@ part. A @foreign import@
declaration
\begin{verbatim}
foreign import cc nm f :: prim_args -> IO prim_res
\end{verbatim}
is the same as
\begin{verbatim}
f :: prim_args -> IO prim_res
f a1 ... an = _ccall_ nm cc a1 ... an
\end{verbatim}
so we reuse the desugaring code in @GHC.HsToCore.Foreign.Call@ to deal with these.
-}
type Binding = (Id, CoreExpr) -- No rec/nonrec structure;
-- the occurrence analyser will sort it all out
dsForeigns :: [LForeignDecl GhcTc]
-> DsM (ForeignStubs, OrdList Binding)
dsForeigns fos = getHooked dsForeignsHook dsForeigns' >>= ($ fos)
dsForeigns' :: [LForeignDecl GhcTc]
-> DsM (ForeignStubs, OrdList Binding)
dsForeigns' []
= return (NoStubs, nilOL)
dsForeigns' fos = do
mod <- getModule
fives <- mapM do_ldecl fos
let
(hs, cs, idss, bindss) = unzip4 fives
fe_ids = concat idss
fe_init_code = foreignExportsInitialiser mod fe_ids
--
return (ForeignStubs
(vcat hs)
(vcat cs $$ fe_init_code),
foldr (appOL . toOL) nilOL bindss)
where
do_ldecl (L loc decl) = putSrcSpanDs loc (do_decl decl)
do_decl :: ForeignDecl GhcTc -> DsM (SDoc, SDoc, [Id], [Binding])
do_decl (ForeignImport { fd_name = id, fd_i_ext = co, fd_fi = spec }) = do
traceIf (text "fi start" <+> ppr id)
let id' = unLoc id
(bs, h, c) <- dsFImport id' co spec
traceIf (text "fi end" <+> ppr id)
return (h, c, [], bs)
do_decl (ForeignExport { fd_name = L _ id
, fd_e_ext = co
, fd_fe = CExport
(L _ (CExportStatic _ ext_nm cconv)) _ }) = do
(h, c, _, _) <- dsFExport id co ext_nm cconv False
return (h, c, [id], [])
{-
************************************************************************
* *
\subsection{Foreign import}
* *
************************************************************************
Desugaring foreign imports is just the matter of creating a binding
that on its RHS unboxes its arguments, performs the external call
(using the @CCallOp@ primop), before boxing the result up and returning it.
However, we create a worker/wrapper pair, thus:
foreign import f :: Int -> IO Int
==>
f x = IO ( \s -> case x of { I# x# ->
case fw s x# of { (# s1, y# #) ->
(# s1, I# y# #)}})
fw s x# = ccall f s x#
The strictness/CPR analyser won't do this automatically because it doesn't look
inside returned tuples; but inlining this wrapper is a Really Good Idea
because it exposes the boxing to the call site.
-}
dsFImport :: Id
-> Coercion
-> ForeignImport
-> DsM ([Binding], SDoc, SDoc)
dsFImport id co (CImport cconv safety mHeader spec _) =
dsCImport id co spec (unLoc cconv) (unLoc safety) mHeader
dsCImport :: Id
-> Coercion
-> CImportSpec
-> CCallConv
-> Safety
-> Maybe Header
-> DsM ([Binding], SDoc, SDoc)
dsCImport id co (CLabel cid) cconv _ _ = do
dflags <- getDynFlags
let ty = coercionLKind co
platform = targetPlatform dflags
fod = case tyConAppTyCon_maybe (dropForAlls ty) of
Just tycon
| tyConUnique tycon == funPtrTyConKey ->
IsFunction
_ -> IsData
(resTy, foRhs) <- resultWrapper ty
ASSERT(fromJust resTy `eqType` addrPrimTy) -- typechecker ensures this
let
rhs = foRhs (Lit (LitLabel cid stdcall_info fod))
rhs' = Cast rhs co
stdcall_info = fun_type_arg_stdcall_info platform cconv ty
in
return ([(id, rhs')], empty, empty)
dsCImport id co (CFunction target) cconv@PrimCallConv safety _
= dsPrimCall id co (CCall (CCallSpec target cconv safety))
dsCImport id co (CFunction target) cconv safety mHeader
= dsFCall id co (CCall (CCallSpec target cconv safety)) mHeader
dsCImport id co CWrapper cconv _ _
= dsFExportDynamic id co cconv
-- For stdcall labels, if the type was a FunPtr or newtype thereof,
-- then we need to calculate the size of the arguments in order to add
-- the @n suffix to the label.
fun_type_arg_stdcall_info :: Platform -> CCallConv -> Type -> Maybe Int
fun_type_arg_stdcall_info platform StdCallConv ty
| Just (tc,[arg_ty]) <- splitTyConApp_maybe ty,
tyConUnique tc == funPtrTyConKey
= let
(bndrs, _) = tcSplitPiTys arg_ty
fe_arg_tys = mapMaybe binderRelevantType_maybe bndrs
in Just $ sum (map (widthInBytes . typeWidth . typeCmmType platform . getPrimTyOf) fe_arg_tys)
fun_type_arg_stdcall_info _ _other_conv _
= Nothing
{-
************************************************************************
* *
\subsection{Foreign calls}
* *
************************************************************************
-}
dsFCall :: Id -> Coercion -> ForeignCall -> Maybe Header
-> DsM ([(Id, Expr TyVar)], SDoc, SDoc)
dsFCall fn_id co fcall mDeclHeader = do
let
ty = coercionLKind co
(tv_bndrs, rho) = tcSplitForAllVarBndrs ty
(arg_tys, io_res_ty) = tcSplitFunTys rho
args <- newSysLocalsDs arg_tys -- no FFI levity-polymorphism
(val_args, arg_wrappers) <- mapAndUnzipM unboxArg (map Var args)
let
work_arg_ids = [v | Var v <- val_args] -- All guaranteed to be vars
(ccall_result_ty, res_wrapper) <- boxResult io_res_ty
ccall_uniq <- newUnique
work_uniq <- newUnique
dflags <- getDynFlags
(fcall', cDoc) <-
case fcall of
CCall (CCallSpec (StaticTarget _ cName mUnitId isFun)
CApiConv safety) ->
do wrapperName <- mkWrapperName "ghc_wrapper" (unpackFS cName)
let fcall' = CCall (CCallSpec
(StaticTarget NoSourceText
wrapperName mUnitId
True)
CApiConv safety)
c = includes
$$ fun_proto <+> braces (cRet <> semi)
includes = vcat [ text "#include \"" <> ftext h
<> text "\""
| Header _ h <- nub headers ]
fun_proto = cResType <+> pprCconv <+> ppr wrapperName <> parens argTypes
cRet
| isVoidRes = cCall
| otherwise = text "return" <+> cCall
cCall = if isFun
then ppr cName <> parens argVals
else if null arg_tys
then ppr cName
else panic "dsFCall: Unexpected arguments to FFI value import"
raw_res_ty = case tcSplitIOType_maybe io_res_ty of
Just (_ioTyCon, res_ty) -> res_ty
Nothing -> io_res_ty
isVoidRes = raw_res_ty `eqType` unitTy
(mHeader, cResType)
| isVoidRes = (Nothing, text "void")
| otherwise = toCType raw_res_ty
pprCconv = ccallConvAttribute CApiConv
mHeadersArgTypeList
= [ (header, cType <+> char 'a' <> int n)
| (t, n) <- zip arg_tys [1..]
, let (header, cType) = toCType (scaledThing t) ]
(mHeaders, argTypeList) = unzip mHeadersArgTypeList
argTypes = if null argTypeList
then text "void"
else hsep $ punctuate comma argTypeList
mHeaders' = mDeclHeader : mHeader : mHeaders
headers = catMaybes mHeaders'
argVals = hsep $ punctuate comma
[ char 'a' <> int n
| (_, n) <- zip arg_tys [1..] ]
return (fcall', c)
_ ->
return (fcall, empty)
let
-- Build the worker
worker_ty = mkForAllTys tv_bndrs (mkVisFunTysMany (map idType work_arg_ids) ccall_result_ty)
tvs = map binderVar tv_bndrs
the_ccall_app = mkFCall dflags ccall_uniq fcall' val_args ccall_result_ty
work_rhs = mkLams tvs (mkLams work_arg_ids the_ccall_app)
work_id = mkSysLocal (fsLit "$wccall") work_uniq Many worker_ty
-- Build the wrapper
work_app = mkApps (mkVarApps (Var work_id) tvs) val_args
wrapper_body = foldr ($) (res_wrapper work_app) arg_wrappers
wrap_rhs = mkLams (tvs ++ args) wrapper_body
wrap_rhs' = Cast wrap_rhs co
fn_id_w_inl = fn_id `setIdUnfolding` mkInlineUnfoldingWithArity
(length args) wrap_rhs'
return ([(work_id, work_rhs), (fn_id_w_inl, wrap_rhs')], empty, cDoc)
{-
************************************************************************
* *
\subsection{Primitive calls}
* *
************************************************************************
This is for `@foreign import prim@' declarations.
Currently, at the core level we pretend that these primitive calls are
foreign calls. It may make more sense in future to have them as a distinct
kind of Id, or perhaps to bundle them with PrimOps since semantically and
for calling convention they are really prim ops.
-}
dsPrimCall :: Id -> Coercion -> ForeignCall
-> DsM ([(Id, Expr TyVar)], SDoc, SDoc)
dsPrimCall fn_id co fcall = do
let
ty = coercionLKind co
(tvs, fun_ty) = tcSplitForAllTys ty
(arg_tys, io_res_ty) = tcSplitFunTys fun_ty
args <- newSysLocalsDs arg_tys -- no FFI levity-polymorphism
ccall_uniq <- newUnique
dflags <- getDynFlags
let
call_app = mkFCall dflags ccall_uniq fcall (map Var args) io_res_ty
rhs = mkLams tvs (mkLams args call_app)
rhs' = Cast rhs co
return ([(fn_id, rhs')], empty, empty)
{-
************************************************************************
* *
\subsection{Foreign export}
* *
************************************************************************
The function that does most of the work for `@foreign export@' declarations.
(see below for the boilerplate code a `@foreign export@' declaration expands
into.)
For each `@foreign export foo@' in a module M we generate:
\begin{itemize}
\item a C function `@foo@', which calls
\item a Haskell stub `@M.\$ffoo@', which calls
\end{itemize}
the user-written Haskell function `@M.foo@'.
-}
dsFExport :: Id -- Either the exported Id,
-- or the foreign-export-dynamic constructor
-> Coercion -- Coercion between the Haskell type callable
-- from C, and its representation type
-> CLabelString -- The name to export to C land
-> CCallConv
-> Bool -- True => foreign export dynamic
-- so invoke IO action that's hanging off
-- the first argument's stable pointer
-> DsM ( SDoc -- contents of Module_stub.h
, SDoc -- contents of Module_stub.c
, String -- string describing type to pass to createAdj.
, Int -- size of args to stub function
)
dsFExport fn_id co ext_name cconv isDyn = do
let
ty = coercionRKind co
(bndrs, orig_res_ty) = tcSplitPiTys ty
fe_arg_tys' = mapMaybe binderRelevantType_maybe bndrs
-- We must use tcSplits here, because we want to see
-- the (IO t) in the corner of the type!
fe_arg_tys | isDyn = tail fe_arg_tys'
| otherwise = fe_arg_tys'
-- Look at the result type of the exported function, orig_res_ty
-- If it's IO t, return (t, True)
-- If it's plain t, return (t, False)
(res_ty, is_IO_res_ty) = case tcSplitIOType_maybe orig_res_ty of
-- The function already returns IO t
Just (_ioTyCon, res_ty) -> (res_ty, True)
-- The function returns t
Nothing -> (orig_res_ty, False)
dflags <- getDynFlags
return $
mkFExportCBits dflags ext_name
(if isDyn then Nothing else Just fn_id)
fe_arg_tys res_ty is_IO_res_ty cconv
{-
@foreign import "wrapper"@ (previously "foreign export dynamic") lets
you dress up Haskell IO actions of some fixed type behind an
externally callable interface (i.e., as a C function pointer). Useful
for callbacks and stuff.
\begin{verbatim}
type Fun = Bool -> Int -> IO Int
foreign import "wrapper" f :: Fun -> IO (FunPtr Fun)
-- Haskell-visible constructor, which is generated from the above:
-- SUP: No check for NULL from createAdjustor anymore???
f :: Fun -> IO (FunPtr Fun)
f cback =
bindIO (newStablePtr cback)
(\StablePtr sp# -> IO (\s1# ->
case _ccall_ createAdjustor cconv sp# ``f_helper'' <arg info> s1# of
(# s2#, a# #) -> (# s2#, A# a# #)))
foreign import "&f_helper" f_helper :: FunPtr (StablePtr Fun -> Fun)
-- and the helper in C: (approximately; see `mkFExportCBits` below)
f_helper(StablePtr s, HsBool b, HsInt i)
{
Capability *cap;
cap = rts_lock();
rts_evalIO(&cap,
rts_apply(rts_apply(deRefStablePtr(s),
rts_mkBool(b)), rts_mkInt(i)));
rts_unlock(cap);
}
\end{verbatim}
-}
dsFExportDynamic :: Id
-> Coercion
-> CCallConv
-> DsM ([Binding], SDoc, SDoc)
dsFExportDynamic id co0 cconv = do
mod <- getModule
dflags <- getDynFlags
let platform = targetPlatform dflags
let fe_nm = mkFastString $ zEncodeString
(moduleStableString mod ++ "$" ++ toCName dflags id)
-- Construct the label based on the passed id, don't use names
-- depending on Unique. See #13807 and Note [Unique Determinism].
cback <- newSysLocalDs arg_mult arg_ty
newStablePtrId <- dsLookupGlobalId newStablePtrName
stable_ptr_tycon <- dsLookupTyCon stablePtrTyConName
let
stable_ptr_ty = mkTyConApp stable_ptr_tycon [arg_ty]
export_ty = mkVisFunTyMany stable_ptr_ty arg_ty
bindIOId <- dsLookupGlobalId bindIOName
stbl_value <- newSysLocalDs Many stable_ptr_ty
(h_code, c_code, typestring, args_size) <- dsFExport id (mkRepReflCo export_ty) fe_nm cconv True
let
{-
The arguments to the external function which will
create a little bit of (template) code on the fly
for allowing the (stable pointed) Haskell closure
to be entered using an external calling convention
(stdcall, ccall).
-}
adj_args = [ mkIntLit platform (fromIntegral (ccallConvToInt cconv))
, Var stbl_value
, Lit (LitLabel fe_nm mb_sz_args IsFunction)
, Lit (mkLitString typestring)
]
-- name of external entry point providing these services.
-- (probably in the RTS.)
adjustor = fsLit "createAdjustor"
-- Determine the number of bytes of arguments to the stub function,
-- so that we can attach the '@N' suffix to its label if it is a
-- stdcall on Windows.
mb_sz_args = case cconv of
StdCallConv -> Just args_size
_ -> Nothing
ccall_adj <- dsCCall adjustor adj_args PlayRisky (mkTyConApp io_tc [res_ty])
-- PlayRisky: the adjustor doesn't allocate in the Haskell heap or do a callback
let io_app = mkLams tvs $
Lam cback $
mkApps (Var bindIOId)
[ Type stable_ptr_ty
, Type res_ty
, mkApps (Var newStablePtrId) [ Type arg_ty, Var cback ]
, Lam stbl_value ccall_adj
]
fed = (id `setInlineActivation` NeverActive, Cast io_app co0)
-- Never inline the f.e.d. function, because the litlit
-- might not be in scope in other modules.
return ([fed], h_code, c_code)
where
ty = coercionLKind co0
(tvs,sans_foralls) = tcSplitForAllTys ty
([Scaled arg_mult arg_ty], fn_res_ty) = tcSplitFunTys sans_foralls
Just (io_tc, res_ty) = tcSplitIOType_maybe fn_res_ty
-- Must have an IO type; hence Just
toCName :: DynFlags -> Id -> String
toCName dflags i = showSDoc dflags (pprCode CStyle (ppr (idName i)))
{-
*
\subsection{Generating @foreign export@ stubs}
*
For each @foreign export@ function, a C stub function is generated.
The C stub constructs the application of the exported Haskell function
using the hugs/ghc rts invocation API.
-}
mkFExportCBits :: DynFlags
-> FastString
-> Maybe Id -- Just==static, Nothing==dynamic
-> [Type]
-> Type
-> Bool -- True <=> returns an IO type
-> CCallConv
-> (SDoc,
SDoc,
String, -- the argument reps
Int -- total size of arguments
)
mkFExportCBits dflags c_nm maybe_target arg_htys res_hty is_IO_res_ty cc
= (header_bits, c_bits, type_string,
sum [ widthInBytes (typeWidth rep) | (_,_,_,rep) <- aug_arg_info] -- all the args
-- NB. the calculation here isn't strictly speaking correct.
-- We have a primitive Haskell type (eg. Int#, Double#), and
-- we want to know the size, when passed on the C stack, of
-- the associated C type (eg. HsInt, HsDouble). We don't have
-- this information to hand, but we know what GHC's conventions
-- are for passing around the primitive Haskell types, so we
-- use that instead. I hope the two coincide --SDM
)
where
platform = targetPlatform dflags
-- list the arguments to the C function
arg_info :: [(SDoc, -- arg name
SDoc, -- C type
Type, -- Haskell type
CmmType)] -- the CmmType
arg_info = [ let stg_type = showStgType ty
cmm_type = typeCmmType platform (getPrimTyOf ty)
stack_type
= if int_promote (typeTyCon ty)
then text "HsWord"
else stg_type
in
(arg_cname n stg_type stack_type,
stg_type,
ty,
cmm_type)
| (ty,n) <- zip arg_htys [1::Int ..] ]
int_promote ty_con
| ty_con `hasKey` int8TyConKey = True
| ty_con `hasKey` int16TyConKey = True
| ty_con `hasKey` int32TyConKey
, platformWordSizeInBytes platform > 4
= True
| ty_con `hasKey` word8TyConKey = True
| ty_con `hasKey` word16TyConKey = True
| ty_con `hasKey` word32TyConKey
, platformWordSizeInBytes platform > 4
= True
| otherwise = False
arg_cname n stg_ty stack_ty
| libffi = parens (stg_ty) <> char '*' <>
parens (stack_ty <> char '*') <>
text "args" <> brackets (int (n-1))
| otherwise = text ('a':show n)
-- generate a libffi-style stub if this is a "wrapper" and libffi is enabled
libffi = platformMisc_libFFI (platformMisc dflags) && isNothing maybe_target
type_string
-- libffi needs to know the result type too:
| libffi = primTyDescChar platform res_hty : arg_type_string
| otherwise = arg_type_string
arg_type_string = [primTyDescChar platform ty | (_,_,ty,_) <- arg_info]
-- just the real args
-- add some auxiliary args; the stable ptr in the wrapper case, and
-- a slot for the dummy return address in the wrapper + ccall case
aug_arg_info
| isNothing maybe_target = stable_ptr_arg : insertRetAddr platform cc arg_info
| otherwise = arg_info
stable_ptr_arg =
(text "the_stableptr", text "StgStablePtr", undefined,
typeCmmType platform (mkStablePtrPrimTy alphaTy))
-- stuff to do with the return type of the C function
res_hty_is_unit = res_hty `eqType` unitTy -- Look through any newtypes
cResType | res_hty_is_unit = text "void"
| otherwise = showStgType res_hty
-- when the return type is integral and word-sized or smaller, it
-- must be assigned as type ffi_arg (#3516). To see what type
-- libffi is expecting here, take a look in its own testsuite, e.g.
-- libffi/testsuite/libffi.call/cls_align_ulonglong.c
ffi_cResType
| is_ffi_arg_type = text "ffi_arg"
| otherwise = cResType
where
res_ty_key = getUnique (getName (typeTyCon res_hty))
is_ffi_arg_type = res_ty_key `notElem`
[floatTyConKey, doubleTyConKey,
int64TyConKey, word64TyConKey]
-- Now we can cook up the prototype for the exported function.
pprCconv = ccallConvAttribute cc
header_bits = text "extern" <+> fun_proto <> semi
fun_args
| null aug_arg_info = text "void"
| otherwise = hsep $ punctuate comma
$ map (\(nm,ty,_,_) -> ty <+> nm) aug_arg_info
fun_proto
| libffi
= text "void" <+> ftext c_nm <>
parens (text "void *cif STG_UNUSED, void* resp, void** args, void* the_stableptr")
| otherwise
= cResType <+> pprCconv <+> ftext c_nm <> parens fun_args
-- the target which will form the root of what we ask rts_evalIO to run
the_cfun
= case maybe_target of
Nothing -> text "(StgClosure*)deRefStablePtr(the_stableptr)"
Just hs_fn -> char '&' <> ppr hs_fn <> text "_closure"
cap = text "cap" <> comma
-- the expression we give to rts_evalIO
expr_to_run
= foldl' appArg the_cfun arg_info -- NOT aug_arg_info
where
appArg acc (arg_cname, _, arg_hty, _)
= text "rts_apply"
<> parens (cap <> acc <> comma <> mkHObj arg_hty <> parens (cap <> arg_cname))
-- various other bits for inside the fn
declareResult = text "HaskellObj ret;"
declareCResult | res_hty_is_unit = empty
| otherwise = cResType <+> text "cret;"
assignCResult | res_hty_is_unit = empty
| otherwise =
text "cret=" <> unpackHObj res_hty <> parens (text "ret") <> semi
-- an extern decl for the fn being called
extern_decl
= case maybe_target of
Nothing -> empty
Just hs_fn -> text "extern StgClosure " <> ppr hs_fn <> text "_closure" <> semi
-- finally, the whole darn thing
c_bits =
space $$
extern_decl $$
fun_proto $$
vcat
[ lbrace
, text "Capability *cap;"
, declareResult
, declareCResult
, text "cap = rts_lock();"
-- create the application + perform it.
, text "rts_evalIO" <> parens (
char '&' <> cap <>
text "rts_apply" <> parens (
cap <>
text "(HaskellObj)"
<> ptext (if is_IO_res_ty
then (sLit "runIO_closure")
else (sLit "runNonIO_closure"))
<> comma
<> expr_to_run
) <+> comma
<> text "&ret"
) <> semi
, text "rts_checkSchedStatus" <> parens (doubleQuotes (ftext c_nm)
<> comma <> text "cap") <> semi
, assignCResult
, text "rts_unlock(cap);"
, ppUnless res_hty_is_unit $
if libffi
then char '*' <> parens (ffi_cResType <> char '*') <>
text "resp = cret;"
else text "return cret;"
, rbrace
]
foreignExportsInitialiser :: Module -> [Id] -> SDoc
foreignExportsInitialiser mod hs_fns =
-- Initialise foreign exports by registering a stable pointer from an
-- __attribute__((constructor)) function.
-- The alternative is to do this from stginit functions generated in
-- codeGen/CodeGen.hs; however, stginit functions have a negative impact
-- on binary sizes and link times because the static linker will think that
-- all modules that are imported directly or indirectly are actually used by
-- the program.
-- (this is bad for big umbrella modules like Graphics.Rendering.OpenGL)
--
-- See Note [Tracking foreign exports] in rts/ForeignExports.c
vcat
[ text "static struct ForeignExportsList" <+> list_symbol <+> equals
<+> braces (
text ".exports = " <+> export_list <> comma <+>
text ".n_entries = " <+> ppr (length hs_fns))
<> semi
, text "static void " <> ctor_symbol <> text "(void)"
<+> text " __attribute__((constructor));"
, text "static void " <> ctor_symbol <> text "()"
, braces (text "registerForeignExports" <> parens (char '&' <> list_symbol) <> semi)
]
where
mod_str = pprModuleName (moduleName mod)
ctor_symbol = text "stginit_export_" <> mod_str
list_symbol = text "stg_exports_" <> mod_str
export_list = braces $ pprWithCommas closure_ptr hs_fns
closure_ptr :: Id -> SDoc
closure_ptr fn = text "(StgPtr) &" <> ppr fn <> text "_closure"
mkHObj :: Type -> SDoc
mkHObj t = text "rts_mk" <> text (showFFIType t)
unpackHObj :: Type -> SDoc
unpackHObj t = text "rts_get" <> text (showFFIType t)
showStgType :: Type -> SDoc
showStgType t = text "Hs" <> text (showFFIType t)
showFFIType :: Type -> String
showFFIType t = getOccString (getName (typeTyCon t))
toCType :: Type -> (Maybe Header, SDoc)
toCType = f False
where f voidOK t
-- First, if we have (Ptr t) of (FunPtr t), then we need to
-- convert t to a C type and put a * after it. If we don't
-- know a type for t, then "void" is fine, though.
| Just (ptr, [t']) <- splitTyConApp_maybe t
, tyConName ptr `elem` [ptrTyConName, funPtrTyConName]
= case f True t' of
(mh, cType') ->
(mh, cType' <> char '*')
-- Otherwise, if we have a type constructor application, then
-- see if there is a C type associated with that constructor.
-- Note that we aren't looking through type synonyms or
-- anything, as it may be the synonym that is annotated.
| Just tycon <- tyConAppTyConPicky_maybe t
, Just (CType _ mHeader (_,cType)) <- tyConCType_maybe tycon
= (mHeader, ftext cType)
-- If we don't know a C type for this type, then try looking
-- through one layer of type synonym etc.
| Just t' <- coreView t
= f voidOK t'
-- This may be an 'UnliftedFFITypes'-style ByteArray# argument
-- (which is marshalled like a Ptr)
| Just byteArrayPrimTyCon == tyConAppTyConPicky_maybe t
= (Nothing, text "const void*")
| Just mutableByteArrayPrimTyCon == tyConAppTyConPicky_maybe t
= (Nothing, text "void*")
-- Otherwise we don't know the C type. If we are allowing
-- void then return that; otherwise something has gone wrong.
| voidOK = (Nothing, text "void")
| otherwise
= pprPanic "toCType" (ppr t)
typeTyCon :: Type -> TyCon
typeTyCon ty
| Just (tc, _) <- tcSplitTyConApp_maybe (unwrapType ty)
= tc
| otherwise
= pprPanic "GHC.HsToCore.Foreign.Decl.typeTyCon" (ppr ty)
insertRetAddr :: Platform -> CCallConv
-> [(SDoc, SDoc, Type, CmmType)]
-> [(SDoc, SDoc, Type, CmmType)]
insertRetAddr platform CCallConv args
= case platformArch platform of
ArchX86_64
| platformOS platform == OSMinGW32 ->
-- On other Windows x86_64 we insert the return address
-- after the 4th argument, because this is the point
-- at which we need to flush a register argument to the stack
-- (See rts/Adjustor.c for details).
let go :: Int -> [(SDoc, SDoc, Type, CmmType)]
-> [(SDoc, SDoc, Type, CmmType)]
go 4 args = ret_addr_arg platform : args
go n (arg:args) = arg : go (n+1) args
go _ [] = []
in go 0 args
| otherwise ->
-- On other x86_64 platforms we insert the return address
-- after the 6th integer argument, because this is the point
-- at which we need to flush a register argument to the stack
-- (See rts/Adjustor.c for details).
let go :: Int -> [(SDoc, SDoc, Type, CmmType)]
-> [(SDoc, SDoc, Type, CmmType)]
go 6 args = ret_addr_arg platform : args
go n (arg@(_,_,_,rep):args)
| cmmEqType_ignoring_ptrhood rep b64 = arg : go (n+1) args
| otherwise = arg : go n args
go _ [] = []
in go 0 args
_ ->
ret_addr_arg platform : args
insertRetAddr _ _ args = args
ret_addr_arg :: Platform -> (SDoc, SDoc, Type, CmmType)
ret_addr_arg platform = (text "original_return_addr", text "void*", undefined,
typeCmmType platform addrPrimTy)
-- This function returns the primitive type associated with the boxed
-- type argument to a foreign export (eg. Int ==> Int#).
getPrimTyOf :: Type -> UnaryType
getPrimTyOf ty
| isBoolTy rep_ty = intPrimTy
-- Except for Bool, the types we are interested in have a single constructor
-- with a single primitive-typed argument (see TcType.legalFEArgTyCon).
| otherwise =
case splitDataProductType_maybe rep_ty of
Just (_, _, data_con, [Scaled _ prim_ty]) ->
ASSERT(dataConSourceArity data_con == 1)
ASSERT2(isUnliftedType prim_ty, ppr prim_ty)
prim_ty
_other -> pprPanic "GHC.HsToCore.Foreign.Decl.getPrimTyOf" (ppr ty)
where
rep_ty = unwrapType ty
-- represent a primitive type as a Char, for building a string that
-- described the foreign function type. The types are size-dependent,
-- e.g. 'W' is a signed 32-bit integer.
primTyDescChar :: Platform -> Type -> Char
primTyDescChar platform ty
| ty `eqType` unitTy = 'v'
| otherwise
= case typePrimRep1 (getPrimTyOf ty) of
IntRep -> signed_word
WordRep -> unsigned_word
Int64Rep -> 'L'
Word64Rep -> 'l'
AddrRep -> 'p'
FloatRep -> 'f'
DoubleRep -> 'd'
_ -> pprPanic "primTyDescChar" (ppr ty)
where
(signed_word, unsigned_word) = case platformWordSize platform of
PW4 -> ('W','w')
PW8 -> ('L','l')