Commit b539a820 authored by sewardj's avatar sewardj
Browse files

[project @ 2000-01-25 10:22:55 by sewardj]

genCCall for x86, as supplied, used PUSH et al to move args onto the C
stack ready for the call.  Reasonable as this seems, it causes a
problem with spill code, since the spiller spills relative to %esp and
assumes that %esp doesn't move.  If the args of a ccall involved any
spilled values, the resulting code would be wrong.

The One True Way is to do it like a RISC: move args to the stack
without adjusting %esp for each argument, then adjust it all at once
immediately prior to the call insn and un-adjust it immediately
afterwards.  genCCall now does this.  In general, push/pop and other
C-stack effecting operations should not be generated for the same
reason.
parent 0f74861a
......@@ -2262,17 +2262,15 @@ genCCall fn cconv kind [StInt i]
genCCall fn cconv kind args
= mapUs get_call_arg args `thenUs` \ sizes_and_argCodes ->
= get_call_args args `thenUs` \ (tot_arg_size, argCode) ->
let
(sizes, argCode) = unzip sizes_and_argCodes
tot_arg_size = sum (map (\sz -> case sz of DF -> 8; _ -> 4) sizes)
code2 = asmParThen (map ($ asmVoid) (reverse argCode))
call = [CALL fn__2 ,
code2 = asmParThen (map ($ asmVoid) argCode)
call = [SUB L (OpImm (ImmInt tot_arg_size)) (OpReg esp),
CALL fn__2 ,
ADD L (OpImm (ImmInt tot_arg_size)) (OpReg esp)
]
in
returnSeq (code2) call
returnSeq code2 call
where
-- function names that begin with '.' are assumed to be special
......@@ -2283,42 +2281,52 @@ genCCall fn cconv kind args
'.' -> ImmLit (ptext fn)
_ -> ImmLab (ptext fn)
arg_size DF = 8
arg_size _ = 4
------------
get_call_arg :: StixTree{-current argument-}
-> UniqSM (Size, InstrBlock) -- arg size, code
-- do get_call_arg on each arg, threading the total arg size along
-- process the args right-to-left
get_call_args :: [StixTree] -> UniqSM (Int, [InstrBlock])
get_call_args args
= f 0 args
where
f curr_sz []
= returnUs (curr_sz, [])
f curr_sz (arg:args)
= f curr_sz args `thenUs` \ (new_sz, iblocks) ->
get_call_arg arg new_sz `thenUs` \ (new_sz2, iblock) ->
returnUs (new_sz2, iblock:iblocks)
get_call_arg arg
= get_op arg `thenUs` \ (code, op, sz) ->
------------
get_call_arg :: StixTree{-current argument-}
-> Int{-running total of arg sizes seen so far-}
-> UniqSM (Int, InstrBlock) -- updated tot argsz, code
get_call_arg arg old_sz
= get_op arg `thenUs` \ (code, reg, sz) ->
let new_sz = old_sz + arg_size sz
in
case sz of
DF -> --getNewRegNCG DoubleRep `thenUs` \ tmp ->
returnUs (sz,
DF -> returnUs (new_sz,
code .
--mkSeqInstr (GLD DF op tmp) .
mkSeqInstr (SUB L (OpImm (ImmInt 8)) (OpReg esp)) .
mkSeqInstr (GST DF {-tmp-}op (AddrBaseIndex
(Just esp)
Nothing (ImmInt 0)))
mkSeqInstr (GST DF reg
(AddrBaseIndex (Just esp)
Nothing (ImmInt (- new_sz))))
)
_ -> returnUs (new_sz,
code .
mkSeqInstr (MOV sz (OpReg reg)
(OpAddr
(AddrBaseIndex (Just esp)
Nothing (ImmInt (- new_sz)))))
)
_ -> returnUs (sz,
code . mkSeqInstr (PUSH sz (OpReg op)))
------------
get_op
:: StixTree
-> UniqSM (InstrBlock, {-Operand-}Reg, Size) -- code, operator, size
{-
get_op (StInt i)
= returnUs (asmParThen [], OpImm (ImmInt (fromInteger i)), L)
-> UniqSM (InstrBlock, Reg, Size) -- code, reg, size
get_op (StInd pk mem)
= getAmode mem `thenUs` \ amode ->
let
code = amodeCode amode --asmVoid
addr = amodeAddr amode
sz = primRepToSize pk
in
returnUs (code, OpAddr addr, sz)
-}
get_op op
= getRegister op `thenUs` \ register ->
getNewRegNCG (registerRep register)
......@@ -2329,7 +2337,7 @@ genCCall fn cconv kind args
pk = registerRep register
sz = primRepToSize pk
in
returnUs (code, {-OpReg-} reg, sz)
returnUs (code, reg, sz)
#endif {- i386_TARGET_ARCH -}
-- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
......
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