----------------------------------------------------------------------------- -- -- Code generation for foreign calls. -- -- (c) The University of Glasgow 2004-2006 -- ----------------------------------------------------------------------------- module CgForeignCall ( cgForeignCall, emitForeignCall, emitForeignCall', shimForeignCallArg, emitSaveThreadState, -- will be needed by the Cmm parser emitLoadThreadState, -- ditto emitCloseNursery, emitOpenNursery, ) where import StgSyn import CgProf import CgBindery import CgMonad import CgUtils import Type import TysPrim import ClosureInfo( nonVoidArg ) import CLabel import OldCmm import OldCmmUtils import SMRep import ForeignCall import Constants import StaticFlags import Outputable import Module import FastString import BasicTypes import Control.Monad -- ----------------------------------------------------------------------------- -- Code generation for Foreign Calls cgForeignCall :: [HintedCmmFormal] -- where to put the results -> ForeignCall -- the op -> [StgArg] -- arguments -> StgLiveVars -- live vars, in case we need to save them -> Code cgForeignCall results fcall stg_args live = do reps_n_amodes <- getArgAmodes stg_args let -- Get the *non-void* args, and jiggle them with shimForeignCall arg_exprs = [ shimForeignCallArg stg_arg expr | (stg_arg, (rep,expr)) <- stg_args `zip` reps_n_amodes, nonVoidArg rep] arg_hints = zipWith CmmHinted arg_exprs (map (typeForeignHint.stgArgType) stg_args) -- in emitForeignCall results fcall arg_hints live emitForeignCall :: [HintedCmmFormal] -- where to put the results -> ForeignCall -- the op -> [CmmHinted CmmExpr] -- arguments -> StgLiveVars -- live vars, in case we need to save them -> Code emitForeignCall results (CCall (CCallSpec target cconv safety)) args live = do vols <- getVolatileRegs live srt <- getSRTInfo emitForeignCall' safety results (CmmCallee cmm_target cconv) call_args (Just vols) srt CmmMayReturn where (call_args, cmm_target) = case target of -- If the packageId is Nothing then the label is taken to be in the -- package currently being compiled. StaticTarget lbl mPkgId -> let labelSource = case mPkgId of Nothing -> ForeignLabelInThisPackage Just pkgId -> ForeignLabelInPackage pkgId in ( args , CmmLit (CmmLabel (mkForeignLabel lbl call_size labelSource IsFunction))) -- A label imported with "foreign import ccall "dynamic" ..." -- Note: "dynamic" here doesn't mean "dynamic library". -- Read the FFI spec for details. DynamicTarget -> case args of (CmmHinted fn _):rest -> (rest, fn) [] -> panic "emitForeignCall: DynamicTarget []" -- in the stdcall calling convention, the symbol needs @size appended -- to it, where size is the total number of bytes of arguments. We -- attach this info to the CLabel here, and the CLabel pretty printer -- will generate the suffix when the label is printed. call_size | StdCallConv <- cconv = Just (sum (map (arg_size.cmmExprType.hintlessCmm) args)) | otherwise = Nothing -- ToDo: this might not be correct for 64-bit API arg_size rep = max (widthInBytes (typeWidth rep)) wORD_SIZE -- alternative entry point, used by CmmParse -- the new code generator has utility function emitCCall and emitPrimCall -- which should be used instead of this (the equivalent emitForeignCall -- is not presently exported.) emitForeignCall' :: Safety -> [HintedCmmFormal] -- where to put the results -> CmmCallTarget -- the op -> [CmmHinted CmmExpr] -- arguments -> Maybe [GlobalReg] -- live vars, in case we need to save them -> C_SRT -- the SRT of the calls continuation -> CmmReturnInfo -> Code emitForeignCall' safety results target args vols _srt ret | not (playSafe safety) = do temp_args <- load_args_into_temps args let (caller_save, caller_load) = callerSaveVolatileRegs vols let caller_load' = if ret == CmmNeverReturns then [] else caller_load stmtsC caller_save stmtC (CmmCall target results temp_args ret) stmtsC caller_load' | otherwise = do -- Both 'id' and 'new_base' are GCKindNonPtr because they're -- RTS only objects and are not subject to garbage collection id <- newTemp bWord new_base <- newTemp (cmmRegType (CmmGlobal BaseReg)) temp_args <- load_args_into_temps args temp_target <- load_target_into_temp target let (caller_save, caller_load) = callerSaveVolatileRegs vols emitSaveThreadState stmtsC caller_save -- The CmmUnsafe arguments are only correct because this part -- of the code hasn't been moved into the CPS pass yet. -- Once that happens, this function will just emit a (CmmSafe srt) call, -- and the CPS will be the one to convert that -- to this sequence of three CmmUnsafe calls. stmtC (CmmCall (CmmCallee suspendThread CCallConv) [ CmmHinted id AddrHint ] [ CmmHinted (CmmReg (CmmGlobal BaseReg)) AddrHint , CmmHinted (CmmLit (CmmInt (fromIntegral (fromEnum (playInterruptible safety))) wordWidth)) NoHint] ret) stmtC (CmmCall temp_target results temp_args ret) stmtC (CmmCall (CmmCallee resumeThread CCallConv) [ CmmHinted new_base AddrHint ] [ CmmHinted (CmmReg (CmmLocal id)) AddrHint ] ret) -- Assign the result to BaseReg: we -- might now have a different Capability! stmtC (CmmAssign (CmmGlobal BaseReg) (CmmReg (CmmLocal new_base))) stmtsC caller_load emitLoadThreadState suspendThread, resumeThread :: CmmExpr suspendThread = CmmLit (CmmLabel (mkCmmCodeLabel rtsPackageId (fsLit "suspendThread"))) resumeThread = CmmLit (CmmLabel (mkCmmCodeLabel rtsPackageId (fsLit "resumeThread"))) -- we might need to load arguments into temporaries before -- making the call, because certain global registers might -- overlap with registers that the C calling convention uses -- for passing arguments. -- -- This is a HACK; really it should be done in the back end, but -- it's easier to generate the temporaries here. load_args_into_temps :: [CmmHinted CmmExpr] -> FCode [CmmHinted CmmExpr] load_args_into_temps = mapM arg_assign_temp where arg_assign_temp (CmmHinted e hint) = do tmp <- maybe_assign_temp e return (CmmHinted tmp hint) load_target_into_temp :: CmmCallTarget -> FCode CmmCallTarget load_target_into_temp (CmmCallee expr conv) = do tmp <- maybe_assign_temp expr return (CmmCallee tmp conv) load_target_into_temp other_target = return other_target maybe_assign_temp :: CmmExpr -> FCode CmmExpr maybe_assign_temp e | hasNoGlobalRegs e = return e | otherwise = do -- don't use assignTemp, it uses its own notion of "trivial" -- expressions, which are wrong here. -- this is a NonPtr because it only duplicates an existing reg <- newTemp (cmmExprType e) --TODO FIXME NOW stmtC (CmmAssign (CmmLocal reg) e) return (CmmReg (CmmLocal reg)) -- ----------------------------------------------------------------------------- -- Save/restore the thread state in the TSO -- This stuff can't be done in suspendThread/resumeThread, because it -- refers to global registers which aren't available in the C world. emitSaveThreadState :: Code emitSaveThreadState = do -- CurrentTSO->stackobj->sp = Sp; stmtC $ CmmStore (cmmOffset (CmmLoad (cmmOffset stgCurrentTSO tso_stackobj) bWord) stack_SP) stgSp emitCloseNursery -- and save the current cost centre stack in the TSO when profiling: when opt_SccProfilingOn $ stmtC (CmmStore (cmmOffset stgCurrentTSO tso_CCCS) curCCS) -- CurrentNursery->free = Hp+1; emitCloseNursery :: Code emitCloseNursery = stmtC $ CmmStore nursery_bdescr_free (cmmOffsetW stgHp 1) emitLoadThreadState :: Code emitLoadThreadState = do tso <- newTemp bWord -- TODO FIXME NOW stack <- newTemp bWord -- TODO FIXME NOW stmtsC [ -- tso = CurrentTSO CmmAssign (CmmLocal tso) stgCurrentTSO, -- stack = tso->stackobj CmmAssign (CmmLocal stack) (CmmLoad (cmmOffset (CmmReg (CmmLocal tso)) tso_stackobj) bWord), -- Sp = stack->sp; CmmAssign sp (CmmLoad (cmmOffset (CmmReg (CmmLocal stack)) stack_SP) bWord), -- SpLim = stack->stack + RESERVED_STACK_WORDS; CmmAssign spLim (cmmOffsetW (cmmOffset (CmmReg (CmmLocal stack)) stack_STACK) rESERVED_STACK_WORDS), -- HpAlloc = 0; -- HpAlloc is assumed to be set to non-zero only by a failed -- a heap check, see HeapStackCheck.cmm:GC_GENERIC CmmAssign hpAlloc (CmmLit zeroCLit) ] emitOpenNursery -- and load the current cost centre stack from the TSO when profiling: when opt_SccProfilingOn $ stmtC $ storeCurCCS $ CmmLoad (cmmOffset (CmmReg (CmmLocal tso)) tso_CCCS) bWord emitOpenNursery :: Code emitOpenNursery = stmtsC [ -- Hp = CurrentNursery->free - 1; CmmAssign hp (cmmOffsetW (CmmLoad nursery_bdescr_free gcWord) (-1)), -- HpLim = CurrentNursery->start + -- CurrentNursery->blocks*BLOCK_SIZE_W - 1; CmmAssign hpLim (cmmOffsetExpr (CmmLoad nursery_bdescr_start bWord) (cmmOffset (CmmMachOp mo_wordMul [ CmmMachOp (MO_SS_Conv W32 wordWidth) [CmmLoad nursery_bdescr_blocks b32], CmmLit (mkIntCLit bLOCK_SIZE) ]) (-1) ) ) ] nursery_bdescr_free, nursery_bdescr_start, nursery_bdescr_blocks :: CmmExpr nursery_bdescr_free = cmmOffset stgCurrentNursery oFFSET_bdescr_free nursery_bdescr_start = cmmOffset stgCurrentNursery oFFSET_bdescr_start nursery_bdescr_blocks = cmmOffset stgCurrentNursery oFFSET_bdescr_blocks tso_stackobj, tso_CCCS, stack_STACK, stack_SP :: ByteOff tso_stackobj = closureField oFFSET_StgTSO_stackobj tso_CCCS = closureField oFFSET_StgTSO_cccs stack_STACK = closureField oFFSET_StgStack_stack stack_SP = closureField oFFSET_StgStack_sp closureField :: ByteOff -> ByteOff closureField off = off + fixedHdrSize * wORD_SIZE stgSp, stgHp, stgCurrentTSO, stgCurrentNursery :: CmmExpr stgSp = CmmReg sp stgHp = CmmReg hp stgCurrentTSO = CmmReg currentTSO stgCurrentNursery = CmmReg currentNursery sp, spLim, hp, hpLim, currentTSO, currentNursery, hpAlloc :: CmmReg sp = CmmGlobal Sp spLim = CmmGlobal SpLim hp = CmmGlobal Hp hpLim = CmmGlobal HpLim currentTSO = CmmGlobal CurrentTSO currentNursery = CmmGlobal CurrentNursery hpAlloc = CmmGlobal HpAlloc -- ----------------------------------------------------------------------------- -- For certain types passed to foreign calls, we adjust the actual -- value passed to the call. For ByteArray#/Array# we pass the -- address of the actual array, not the address of the heap object. shimForeignCallArg :: StgArg -> CmmExpr -> CmmExpr shimForeignCallArg arg expr | tycon == arrayPrimTyCon || tycon == mutableArrayPrimTyCon = cmmOffsetB expr arrPtrsHdrSize | tycon == byteArrayPrimTyCon || tycon == mutableByteArrayPrimTyCon = cmmOffsetB expr arrWordsHdrSize | otherwise = expr where -- should be a tycon app, since this is a foreign call tycon = tyConAppTyCon (repType (stgArgType arg))