--- /dev/null
+-- | Generating C calls
+module SPARC.CodeGen.CCall (
+ genCCall
+)
+
+where
+
+import SPARC.CodeGen.Gen64
+import SPARC.CodeGen.Gen32
+import SPARC.CodeGen.Base
+import SPARC.Stack
+import SPARC.Instr
+import SPARC.Imm
+import SPARC.Regs
+import SPARC.Base
+import NCGMonad
+import PIC
+import Instruction
+import Size
+import Reg
+
+import Cmm
+import CLabel
+import BasicTypes
+
+import OrdList
+import FastString
+import Outputable
+
+{-
+ Now the biggest nightmare---calls. Most of the nastiness is buried in
+ @get_arg@, which moves the arguments to the correct registers/stack
+ locations. Apart from that, the code is easy.
+
+ The SPARC calling convention is an absolute
+ nightmare. The first 6x32 bits of arguments are mapped into
+ %o0 through %o5, and the remaining arguments are dumped to the
+ stack, beginning at [%sp+92]. (Note that %o6 == %sp.)
+
+ If we have to put args on the stack, move %o6==%sp down by
+ the number of words to go on the stack, to ensure there's enough space.
+
+ According to Fraser and Hanson's lcc book, page 478, fig 17.2,
+ 16 words above the stack pointer is a word for the address of
+ a structure return value. I use this as a temporary location
+ for moving values from float to int regs. Certainly it isn't
+ safe to put anything in the 16 words starting at %sp, since
+ this area can get trashed at any time due to window overflows
+ caused by signal handlers.
+
+ A final complication (if the above isn't enough) is that
+ we can't blithely calculate the arguments one by one into
+ %o0 .. %o5. Consider the following nested calls:
+
+ fff a (fff b c)
+
+ Naive code moves a into %o0, and (fff b c) into %o1. Unfortunately
+ the inner call will itself use %o0, which trashes the value put there
+ in preparation for the outer call. Upshot: we need to calculate the
+ args into temporary regs, and move those to arg regs or onto the
+ stack only immediately prior to the call proper. Sigh.
+-}
+
+genCCall
+ :: CmmCallTarget -- function to call
+ -> HintedCmmFormals -- where to put the result
+ -> HintedCmmActuals -- arguments (of mixed type)
+ -> NatM InstrBlock
+
+
+
+-- On SPARC under TSO (Total Store Ordering), writes earlier in the instruction stream
+-- are guaranteed to take place before writes afterwards (unlike on PowerPC).
+-- Ref: Section 8.4 of the SPARC V9 Architecture manual.
+--
+-- In the SPARC case we don't need a barrier.
+--
+genCCall (CmmPrim (MO_WriteBarrier)) _ _
+ = do return nilOL
+
+genCCall target dest_regs argsAndHints
+ = do
+ -- strip hints from the arg regs
+ let args :: [CmmExpr]
+ args = map hintlessCmm argsAndHints
+
+
+ -- work out the arguments, and assign them to integer regs
+ argcode_and_vregs <- mapM arg_to_int_vregs args
+ let (argcodes, vregss) = unzip argcode_and_vregs
+ let vregs = concat vregss
+
+ let n_argRegs = length allArgRegs
+ let n_argRegs_used = min (length vregs) n_argRegs
+
+
+ -- deal with static vs dynamic call targets
+ callinsns <- case target of
+ CmmCallee (CmmLit (CmmLabel lbl)) _ ->
+ return (unitOL (CALL (Left (litToImm (CmmLabel lbl))) n_argRegs_used False))
+
+ CmmCallee expr _
+ -> do (dyn_c, [dyn_r]) <- arg_to_int_vregs expr
+ return (dyn_c `snocOL` CALL (Right dyn_r) n_argRegs_used False)
+
+ CmmPrim mop
+ -> do res <- outOfLineFloatOp mop
+ lblOrMopExpr <- case res of
+ Left lbl -> do
+ return (unitOL (CALL (Left (litToImm (CmmLabel lbl))) n_argRegs_used False))
+
+ Right mopExpr -> do
+ (dyn_c, [dyn_r]) <- arg_to_int_vregs mopExpr
+ return (dyn_c `snocOL` CALL (Right dyn_r) n_argRegs_used False)
+
+ return lblOrMopExpr
+
+ let argcode = concatOL argcodes
+
+ let (move_sp_down, move_sp_up)
+ = let diff = length vregs - n_argRegs
+ nn = if odd diff then diff + 1 else diff -- keep 8-byte alignment
+ in if nn <= 0
+ then (nilOL, nilOL)
+ else (unitOL (moveSp (-1*nn)), unitOL (moveSp (1*nn)))
+
+ let transfer_code
+ = toOL (move_final vregs allArgRegs extraStackArgsHere)
+
+ return
+ $ argcode `appOL`
+ move_sp_down `appOL`
+ transfer_code `appOL`
+ callinsns `appOL`
+ unitOL NOP `appOL`
+ move_sp_up `appOL`
+ assign_code dest_regs
+
+
+-- | Generate code to calculate an argument, and move it into one
+-- or two integer vregs.
+arg_to_int_vregs :: CmmExpr -> NatM (OrdList Instr, [Reg])
+arg_to_int_vregs arg
+
+ -- If the expr produces a 64 bit int, then we can just use iselExpr64
+ | isWord64 (cmmExprType arg)
+ = do (ChildCode64 code r_lo) <- iselExpr64 arg
+ let r_hi = getHiVRegFromLo r_lo
+ return (code, [r_hi, r_lo])
+
+ | otherwise
+ = do (src, code) <- getSomeReg arg
+ let pk = cmmExprType arg
+
+ case cmmTypeSize pk of
+
+ -- Load a 64 bit float return value into two integer regs.
+ FF64 -> do
+ v1 <- getNewRegNat II32
+ v2 <- getNewRegNat II32
+
+ let Just f0_high = fPair f0
+
+ let code2 =
+ code `snocOL`
+ FMOV FF64 src f0 `snocOL`
+ ST FF32 f0 (spRel 16) `snocOL`
+ LD II32 (spRel 16) v1 `snocOL`
+ ST FF32 f0_high (spRel 16) `snocOL`
+ LD II32 (spRel 16) v2
+
+ return (code2, [v1,v2])
+
+ -- Load a 32 bit float return value into an integer reg
+ FF32 -> do
+ v1 <- getNewRegNat II32
+
+ let code2 =
+ code `snocOL`
+ ST FF32 src (spRel 16) `snocOL`
+ LD II32 (spRel 16) v1
+
+ return (code2, [v1])
+
+ -- Move an integer return value into its destination reg.
+ _ -> do
+ v1 <- getNewRegNat II32
+
+ let code2 =
+ code `snocOL`
+ OR False g0 (RIReg src) v1
+
+ return (code2, [v1])
+
+
+-- | Move args from the integer vregs into which they have been
+-- marshalled, into %o0 .. %o5, and the rest onto the stack.
+--
+move_final :: [Reg] -> [Reg] -> Int -> [Instr]
+
+-- all args done
+move_final [] _ _
+ = []
+
+-- out of aregs; move to stack
+move_final (v:vs) [] offset
+ = ST II32 v (spRel offset)
+ : move_final vs [] (offset+1)
+
+-- move into an arg (%o[0..5]) reg
+move_final (v:vs) (a:az) offset
+ = OR False g0 (RIReg v) a
+ : move_final vs az offset
+
+
+-- | Assign results returned from the call into their
+-- desination regs.
+--
+assign_code :: [CmmHinted LocalReg] -> OrdList Instr
+
+assign_code [] = nilOL
+
+assign_code [CmmHinted dest _hint]
+ = let rep = localRegType dest
+ width = typeWidth rep
+ r_dest = getRegisterReg (CmmLocal dest)
+
+ result
+ | isFloatType rep
+ , W32 <- width
+ = unitOL $ FMOV FF32 (RealReg $ fReg 0) r_dest
+
+ | isFloatType rep
+ , W64 <- width
+ = unitOL $ FMOV FF64 (RealReg $ fReg 0) r_dest
+
+ | not $ isFloatType rep
+ , W32 <- width
+ = unitOL $ mkRegRegMoveInstr (RealReg $ oReg 0) r_dest
+
+ | not $ isFloatType rep
+ , W64 <- width
+ , r_dest_hi <- getHiVRegFromLo r_dest
+ = toOL [ mkRegRegMoveInstr (RealReg $ oReg 0) r_dest_hi
+ , mkRegRegMoveInstr (RealReg $ oReg 1) r_dest]
+
+ | otherwise
+ = panic "SPARC.CodeGen.GenCCall: no match"
+
+ in result
+
+assign_code _
+ = panic "SPARC.CodeGen.GenCCall: no match"
+
+
+
+-- | Generate a call to implement an out-of-line floating point operation
+outOfLineFloatOp
+ :: CallishMachOp
+ -> NatM (Either CLabel CmmExpr)
+
+outOfLineFloatOp mop
+ = do let functionName
+ = outOfLineFloatOp_table mop
+
+ dflags <- getDynFlagsNat
+ mopExpr <- cmmMakeDynamicReference dflags addImportNat CallReference
+ $ mkForeignLabel functionName Nothing True IsFunction
+
+ let mopLabelOrExpr
+ = case mopExpr of
+ CmmLit (CmmLabel lbl) -> Left lbl
+ _ -> Right mopExpr
+
+ return mopLabelOrExpr
+
+
+-- | Decide what C function to use to implement a CallishMachOp
+--
+outOfLineFloatOp_table
+ :: CallishMachOp
+ -> FastString
+
+outOfLineFloatOp_table mop
+ = case mop of
+ MO_F32_Exp -> fsLit "expf"
+ MO_F32_Log -> fsLit "logf"
+ MO_F32_Sqrt -> fsLit "sqrtf"
+ MO_F32_Pwr -> fsLit "powf"
+
+ MO_F32_Sin -> fsLit "sinf"
+ MO_F32_Cos -> fsLit "cosf"
+ MO_F32_Tan -> fsLit "tanf"
+
+ MO_F32_Asin -> fsLit "asinf"
+ MO_F32_Acos -> fsLit "acosf"
+ MO_F32_Atan -> fsLit "atanf"
+
+ MO_F32_Sinh -> fsLit "sinhf"
+ MO_F32_Cosh -> fsLit "coshf"
+ MO_F32_Tanh -> fsLit "tanhf"
+
+ MO_F64_Exp -> fsLit "exp"
+ MO_F64_Log -> fsLit "log"
+ MO_F64_Sqrt -> fsLit "sqrt"
+ MO_F64_Pwr -> fsLit "pow"
+
+ MO_F64_Sin -> fsLit "sin"
+ MO_F64_Cos -> fsLit "cos"
+ MO_F64_Tan -> fsLit "tan"
+
+ MO_F64_Asin -> fsLit "asin"
+ MO_F64_Acos -> fsLit "acos"
+ MO_F64_Atan -> fsLit "atan"
+
+ MO_F64_Sinh -> fsLit "sinh"
+ MO_F64_Cosh -> fsLit "cosh"
+ MO_F64_Tanh -> fsLit "tanh"
+
+ _ -> pprPanic "outOfLineFloatOp(sparc): Unknown callish mach op "
+ (pprCallishMachOp mop)
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