1 -----------------------------------------------------------------------------
3 -- Code generation for foreign calls.
5 -- (c) The University of Glasgow 2004-2006
7 -----------------------------------------------------------------------------
14 emitSaveThreadState, -- will be needed by the Cmm parser
15 emitLoadThreadState, -- ditto
42 -- -----------------------------------------------------------------------------
43 -- Code generation for Foreign Calls
46 :: HintedCmmFormals -- where to put the results
47 -> ForeignCall -- the op
48 -> [StgArg] -- arguments
49 -> StgLiveVars -- live vars, in case we need to save them
51 cgForeignCall results fcall stg_args live
53 reps_n_amodes <- getArgAmodes stg_args
55 -- Get the *non-void* args, and jiggle them with shimForeignCall
56 arg_exprs = [ shimForeignCallArg stg_arg expr
57 | (stg_arg, (rep,expr)) <- stg_args `zip` reps_n_amodes,
60 arg_hints = zipWith CmmHinted
61 arg_exprs (map (typeForeignHint.stgArgType) stg_args)
63 emitForeignCall results fcall arg_hints live
67 :: HintedCmmFormals -- where to put the results
68 -> ForeignCall -- the op
69 -> [CmmHinted CmmExpr] -- arguments
70 -> StgLiveVars -- live vars, in case we need to save them
73 emitForeignCall results (CCall (CCallSpec target cconv safety)) args live
74 = do vols <- getVolatileRegs live
76 emitForeignCall' safety results
77 (CmmCallee cmm_target cconv) call_args (Just vols) srt CmmMayReturn
79 (call_args, cmm_target)
81 -- If the packageId is Nothing then the label is taken to be in the
82 -- package currently being compiled.
83 StaticTarget lbl mPkgId
86 Nothing -> ForeignLabelInThisPackage
87 Just pkgId -> ForeignLabelInPackage pkgId
90 (mkForeignLabel lbl call_size labelSource IsFunction)))
92 -- A label imported with "foreign import ccall "dynamic" ..."
93 -- Note: "dynamic" here doesn't mean "dynamic library".
94 -- Read the FFI spec for details.
95 DynamicTarget -> case args of
96 (CmmHinted fn _):rest -> (rest, fn)
97 [] -> panic "emitForeignCall: DynamicTarget []"
99 -- in the stdcall calling convention, the symbol needs @size appended
100 -- to it, where size is the total number of bytes of arguments. We
101 -- attach this info to the CLabel here, and the CLabel pretty printer
102 -- will generate the suffix when the label is printed.
104 | StdCallConv <- cconv = Just (sum (map (arg_size.cmmExprType.hintlessCmm) args))
105 | otherwise = Nothing
107 -- ToDo: this might not be correct for 64-bit API
108 arg_size rep = max (widthInBytes (typeWidth rep)) wORD_SIZE
111 -- alternative entry point, used by CmmParse
114 -> HintedCmmFormals -- where to put the results
115 -> CmmCallTarget -- the op
116 -> [CmmHinted CmmExpr] -- arguments
117 -> Maybe [GlobalReg] -- live vars, in case we need to save them
118 -> C_SRT -- the SRT of the calls continuation
121 emitForeignCall' safety results target args vols _srt ret
122 | not (playSafe safety) = do
123 temp_args <- load_args_into_temps args
124 let (caller_save, caller_load) = callerSaveVolatileRegs vols
125 let caller_load' = if ret == CmmNeverReturns then [] else caller_load
127 stmtC (CmmCall target results temp_args CmmUnsafe ret)
131 -- Both 'id' and 'new_base' are GCKindNonPtr because they're
132 -- RTS only objects and are not subject to garbage collection
134 new_base <- newTemp (cmmRegType (CmmGlobal BaseReg))
135 temp_args <- load_args_into_temps args
136 temp_target <- load_target_into_temp target
137 let (caller_save, caller_load) = callerSaveVolatileRegs vols
140 -- The CmmUnsafe arguments are only correct because this part
141 -- of the code hasn't been moved into the CPS pass yet.
142 -- Once that happens, this function will just emit a (CmmSafe srt) call,
143 -- and the CPS will be the one to convert that
144 -- to this sequence of three CmmUnsafe calls.
145 stmtC (CmmCall (CmmCallee suspendThread CCallConv)
146 [ CmmHinted id AddrHint ]
147 [ CmmHinted (CmmReg (CmmGlobal BaseReg)) AddrHint ]
149 stmtC (CmmCall temp_target results temp_args CmmUnsafe ret)
150 stmtC (CmmCall (CmmCallee resumeThread CCallConv)
151 [ CmmHinted new_base AddrHint ]
152 [ CmmHinted (CmmReg (CmmLocal id)) AddrHint ]
154 -- Assign the result to BaseReg: we
155 -- might now have a different Capability!
156 stmtC (CmmAssign (CmmGlobal BaseReg) (CmmReg (CmmLocal new_base)))
160 suspendThread, resumeThread :: CmmExpr
161 suspendThread = CmmLit (CmmLabel (mkCmmCodeLabel rtsPackageId (fsLit "suspendThread")))
162 resumeThread = CmmLit (CmmLabel (mkCmmCodeLabel rtsPackageId (fsLit "resumeThread")))
165 -- we might need to load arguments into temporaries before
166 -- making the call, because certain global registers might
167 -- overlap with registers that the C calling convention uses
168 -- for passing arguments.
170 -- This is a HACK; really it should be done in the back end, but
171 -- it's easier to generate the temporaries here.
172 load_args_into_temps :: [CmmHinted CmmExpr] -> FCode [CmmHinted CmmExpr]
173 load_args_into_temps = mapM arg_assign_temp
174 where arg_assign_temp (CmmHinted e hint) = do
175 tmp <- maybe_assign_temp e
176 return (CmmHinted tmp hint)
178 load_target_into_temp :: CmmCallTarget -> FCode CmmCallTarget
179 load_target_into_temp (CmmCallee expr conv) = do
180 tmp <- maybe_assign_temp expr
181 return (CmmCallee tmp conv)
182 load_target_into_temp other_target =
185 maybe_assign_temp :: CmmExpr -> FCode CmmExpr
187 | hasNoGlobalRegs e = return e
189 -- don't use assignTemp, it uses its own notion of "trivial"
190 -- expressions, which are wrong here.
191 -- this is a NonPtr because it only duplicates an existing
192 reg <- newTemp (cmmExprType e) --TODO FIXME NOW
193 stmtC (CmmAssign (CmmLocal reg) e)
194 return (CmmReg (CmmLocal reg))
196 -- -----------------------------------------------------------------------------
197 -- Save/restore the thread state in the TSO
199 -- This stuff can't be done in suspendThread/resumeThread, because it
200 -- refers to global registers which aren't available in the C world.
202 emitSaveThreadState :: Code
203 emitSaveThreadState = do
204 -- CurrentTSO->sp = Sp;
205 stmtC $ CmmStore (cmmOffset stgCurrentTSO tso_SP) stgSp
207 -- and save the current cost centre stack in the TSO when profiling:
208 when opt_SccProfilingOn $
209 stmtC (CmmStore (cmmOffset stgCurrentTSO tso_CCCS) curCCS)
211 -- CurrentNursery->free = Hp+1;
212 emitCloseNursery :: Code
213 emitCloseNursery = stmtC $ CmmStore nursery_bdescr_free (cmmOffsetW stgHp 1)
215 emitLoadThreadState :: Code
216 emitLoadThreadState = do
217 tso <- newTemp bWord -- TODO FIXME NOW
220 CmmAssign (CmmLocal tso) stgCurrentTSO,
222 CmmAssign sp (CmmLoad (cmmOffset (CmmReg (CmmLocal tso)) tso_SP)
224 -- SpLim = tso->stack + RESERVED_STACK_WORDS;
225 CmmAssign spLim (cmmOffsetW (cmmOffset (CmmReg (CmmLocal tso)) tso_STACK)
226 rESERVED_STACK_WORDS),
228 -- HpAlloc is assumed to be set to non-zero only by a failed
229 -- a heap check, see HeapStackCheck.cmm:GC_GENERIC
230 CmmAssign hpAlloc (CmmLit zeroCLit)
233 -- and load the current cost centre stack from the TSO when profiling:
234 when opt_SccProfilingOn $
235 stmtC (CmmStore curCCSAddr
236 (CmmLoad (cmmOffset (CmmReg (CmmLocal tso)) tso_CCCS) bWord))
238 emitOpenNursery :: Code
239 emitOpenNursery = stmtsC [
240 -- Hp = CurrentNursery->free - 1;
241 CmmAssign hp (cmmOffsetW (CmmLoad nursery_bdescr_free gcWord) (-1)),
243 -- HpLim = CurrentNursery->start +
244 -- CurrentNursery->blocks*BLOCK_SIZE_W - 1;
247 (CmmLoad nursery_bdescr_start bWord)
249 (CmmMachOp mo_wordMul [
250 CmmMachOp (MO_SS_Conv W32 wordWidth)
251 [CmmLoad nursery_bdescr_blocks b32],
252 CmmLit (mkIntCLit bLOCK_SIZE)
259 nursery_bdescr_free, nursery_bdescr_start, nursery_bdescr_blocks :: CmmExpr
260 nursery_bdescr_free = cmmOffset stgCurrentNursery oFFSET_bdescr_free
261 nursery_bdescr_start = cmmOffset stgCurrentNursery oFFSET_bdescr_start
262 nursery_bdescr_blocks = cmmOffset stgCurrentNursery oFFSET_bdescr_blocks
264 tso_SP, tso_STACK, tso_CCCS :: ByteOff
265 tso_SP = tsoFieldB oFFSET_StgTSO_sp
266 tso_STACK = tsoFieldB oFFSET_StgTSO_stack
267 tso_CCCS = tsoProfFieldB oFFSET_StgTSO_CCCS
269 -- The TSO struct has a variable header, and an optional StgTSOProfInfo in
270 -- the middle. The fields we're interested in are after the StgTSOProfInfo.
271 tsoFieldB :: ByteOff -> ByteOff
273 | opt_SccProfilingOn = off + sIZEOF_StgTSOProfInfo + fixedHdrSize * wORD_SIZE
274 | otherwise = off + fixedHdrSize * wORD_SIZE
276 tsoProfFieldB :: ByteOff -> ByteOff
277 tsoProfFieldB off = off + fixedHdrSize * wORD_SIZE
279 stgSp, stgHp, stgCurrentTSO, stgCurrentNursery :: CmmExpr
282 stgCurrentTSO = CmmReg currentTSO
283 stgCurrentNursery = CmmReg currentNursery
285 sp, spLim, hp, hpLim, currentTSO, currentNursery, hpAlloc :: CmmReg
287 spLim = CmmGlobal SpLim
289 hpLim = CmmGlobal HpLim
290 currentTSO = CmmGlobal CurrentTSO
291 currentNursery = CmmGlobal CurrentNursery
292 hpAlloc = CmmGlobal HpAlloc
294 -- -----------------------------------------------------------------------------
295 -- For certain types passed to foreign calls, we adjust the actual
296 -- value passed to the call. For ByteArray#/Array# we pass the
297 -- address of the actual array, not the address of the heap object.
299 shimForeignCallArg :: StgArg -> CmmExpr -> CmmExpr
300 shimForeignCallArg arg expr
301 | tycon == arrayPrimTyCon || tycon == mutableArrayPrimTyCon
302 = cmmOffsetB expr arrPtrsHdrSize
304 | tycon == byteArrayPrimTyCon || tycon == mutableByteArrayPrimTyCon
305 = cmmOffsetB expr arrWordsHdrSize
309 -- should be a tycon app, since this is a foreign call
310 tycon = tyConAppTyCon (repType (stgArgType arg))