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
148 , CmmHinted (CmmLit (CmmInt (fromIntegral (fromEnum (playInterruptible safety))) wordWidth)) NoHint]
150 stmtC (CmmCall temp_target results temp_args CmmUnsafe ret)
151 stmtC (CmmCall (CmmCallee resumeThread CCallConv)
152 [ CmmHinted new_base AddrHint ]
153 [ CmmHinted (CmmReg (CmmLocal id)) AddrHint ]
155 -- Assign the result to BaseReg: we
156 -- might now have a different Capability!
157 stmtC (CmmAssign (CmmGlobal BaseReg) (CmmReg (CmmLocal new_base)))
161 suspendThread, resumeThread :: CmmExpr
162 suspendThread = CmmLit (CmmLabel (mkCmmCodeLabel rtsPackageId (fsLit "suspendThread")))
163 resumeThread = CmmLit (CmmLabel (mkCmmCodeLabel rtsPackageId (fsLit "resumeThread")))
166 -- we might need to load arguments into temporaries before
167 -- making the call, because certain global registers might
168 -- overlap with registers that the C calling convention uses
169 -- for passing arguments.
171 -- This is a HACK; really it should be done in the back end, but
172 -- it's easier to generate the temporaries here.
173 load_args_into_temps :: [CmmHinted CmmExpr] -> FCode [CmmHinted CmmExpr]
174 load_args_into_temps = mapM arg_assign_temp
175 where arg_assign_temp (CmmHinted e hint) = do
176 tmp <- maybe_assign_temp e
177 return (CmmHinted tmp hint)
179 load_target_into_temp :: CmmCallTarget -> FCode CmmCallTarget
180 load_target_into_temp (CmmCallee expr conv) = do
181 tmp <- maybe_assign_temp expr
182 return (CmmCallee tmp conv)
183 load_target_into_temp other_target =
186 maybe_assign_temp :: CmmExpr -> FCode CmmExpr
188 | hasNoGlobalRegs e = return e
190 -- don't use assignTemp, it uses its own notion of "trivial"
191 -- expressions, which are wrong here.
192 -- this is a NonPtr because it only duplicates an existing
193 reg <- newTemp (cmmExprType e) --TODO FIXME NOW
194 stmtC (CmmAssign (CmmLocal reg) e)
195 return (CmmReg (CmmLocal reg))
197 -- -----------------------------------------------------------------------------
198 -- Save/restore the thread state in the TSO
200 -- This stuff can't be done in suspendThread/resumeThread, because it
201 -- refers to global registers which aren't available in the C world.
203 emitSaveThreadState :: Code
204 emitSaveThreadState = do
205 -- CurrentTSO->stackobj->sp = Sp;
206 stmtC $ CmmStore (cmmOffset (CmmLoad (cmmOffset stgCurrentTSO tso_stackobj) bWord)
209 -- and save the current cost centre stack in the TSO when profiling:
210 when opt_SccProfilingOn $
211 stmtC (CmmStore (cmmOffset stgCurrentTSO tso_CCCS) curCCS)
213 -- CurrentNursery->free = Hp+1;
214 emitCloseNursery :: Code
215 emitCloseNursery = stmtC $ CmmStore nursery_bdescr_free (cmmOffsetW stgHp 1)
217 emitLoadThreadState :: Code
218 emitLoadThreadState = do
219 tso <- newTemp bWord -- TODO FIXME NOW
220 stack <- newTemp bWord -- TODO FIXME NOW
223 CmmAssign (CmmLocal tso) stgCurrentTSO,
224 -- stack = tso->stackobj
225 CmmAssign (CmmLocal stack) (CmmLoad (cmmOffset (CmmReg (CmmLocal tso)) tso_stackobj) bWord),
227 CmmAssign sp (CmmLoad (cmmOffset (CmmReg (CmmLocal stack)) stack_SP)
229 -- SpLim = stack->stack + RESERVED_STACK_WORDS;
230 CmmAssign spLim (cmmOffsetW (cmmOffset (CmmReg (CmmLocal stack)) stack_STACK)
231 rESERVED_STACK_WORDS),
233 -- HpAlloc is assumed to be set to non-zero only by a failed
234 -- a heap check, see HeapStackCheck.cmm:GC_GENERIC
235 CmmAssign hpAlloc (CmmLit zeroCLit)
238 -- and load the current cost centre stack from the TSO when profiling:
239 when opt_SccProfilingOn $
240 stmtC (CmmStore curCCSAddr
241 (CmmLoad (cmmOffset (CmmReg (CmmLocal tso)) tso_CCCS) bWord))
243 emitOpenNursery :: Code
244 emitOpenNursery = stmtsC [
245 -- Hp = CurrentNursery->free - 1;
246 CmmAssign hp (cmmOffsetW (CmmLoad nursery_bdescr_free gcWord) (-1)),
248 -- HpLim = CurrentNursery->start +
249 -- CurrentNursery->blocks*BLOCK_SIZE_W - 1;
252 (CmmLoad nursery_bdescr_start bWord)
254 (CmmMachOp mo_wordMul [
255 CmmMachOp (MO_SS_Conv W32 wordWidth)
256 [CmmLoad nursery_bdescr_blocks b32],
257 CmmLit (mkIntCLit bLOCK_SIZE)
264 nursery_bdescr_free, nursery_bdescr_start, nursery_bdescr_blocks :: CmmExpr
265 nursery_bdescr_free = cmmOffset stgCurrentNursery oFFSET_bdescr_free
266 nursery_bdescr_start = cmmOffset stgCurrentNursery oFFSET_bdescr_start
267 nursery_bdescr_blocks = cmmOffset stgCurrentNursery oFFSET_bdescr_blocks
269 tso_stackobj, tso_CCCS, stack_STACK, stack_SP :: ByteOff
270 tso_stackobj = closureField oFFSET_StgTSO_stackobj
271 tso_CCCS = closureField oFFSET_StgTSO_CCCS
272 stack_STACK = closureField oFFSET_StgStack_stack
273 stack_SP = closureField oFFSET_StgStack_sp
275 closureField :: ByteOff -> ByteOff
276 closureField off = off + fixedHdrSize * wORD_SIZE
278 stgSp, stgHp, stgCurrentTSO, stgCurrentNursery :: CmmExpr
281 stgCurrentTSO = CmmReg currentTSO
282 stgCurrentNursery = CmmReg currentNursery
284 sp, spLim, hp, hpLim, currentTSO, currentNursery, hpAlloc :: CmmReg
286 spLim = CmmGlobal SpLim
288 hpLim = CmmGlobal HpLim
289 currentTSO = CmmGlobal CurrentTSO
290 currentNursery = CmmGlobal CurrentNursery
291 hpAlloc = CmmGlobal HpAlloc
293 -- -----------------------------------------------------------------------------
294 -- For certain types passed to foreign calls, we adjust the actual
295 -- value passed to the call. For ByteArray#/Array# we pass the
296 -- address of the actual array, not the address of the heap object.
298 shimForeignCallArg :: StgArg -> CmmExpr -> CmmExpr
299 shimForeignCallArg arg expr
300 | tycon == arrayPrimTyCon || tycon == mutableArrayPrimTyCon
301 = cmmOffsetB expr arrPtrsHdrSize
303 | tycon == byteArrayPrimTyCon || tycon == mutableByteArrayPrimTyCon
304 = cmmOffsetB expr arrWordsHdrSize
308 -- should be a tycon app, since this is a foreign call
309 tycon = tyConAppTyCon (repType (stgArgType arg))