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|
signature X86REWRITE_PSEUDO = sig
structure F : FLOWGRAPH
(*
* Takes a cluster and returns a range of registers to prohibit
* from spilling. The arguments are:
* 1. The first pseudo register
* 2. The regmap before RA32. If this is guaranteed to be
* an identity you can use the identity function.
* I use I.C.lookup regmap.
*
* 3. The cluster.
*
* It returns a range of registers.
*
* NOTE: this version does not assume that the original regmap
* is an identity. So there is some ugly regmap business to
* take care of.
*
*)
val rewrite :
{ firstPseudo : F.I.C.cell,
originalRegmap : F.I.C.cell -> F.I.C.cell,
pruneCellSets : bool (* should we remove references to memory
* registers from all cell sets?
*)
} -> F.cluster -> F.I.C.cell * F.I.C.cell
end
functor X86RewritePseudo
(structure Instr : X86INSTR
structure Flowgraph : FLOWGRAPH where I = Instr
val ea : int -> Instr.operand) : X86REWRITE_PSEUDO =
struct
structure C = X86Cells
structure I = Instr
structure F = Flowgraph
fun error msg = MLRiscErrorMsg.error("X86RewritePseudo",msg)
fun rewrite {firstPseudo, originalRegmap, pruneCellSets}
(F.CLUSTER{blocks, regmap, ...}) =
let
val first = C.newReg()
val lookup = C.lookup regmap
fun shuffle(dests, srcs, tmp) = let
fun move(rd,rs) = I.MOVE{mvOp=I.MOVL, src=rs, dst=rd}
fun loop((p as (rd, dst, rs, src))::rest, changed, used, done, instrs) =
if List.exists (fn (r : I.C.cell) => dst=r) used then
loop(rest, changed, used, p::done, instrs)
else
loop(rest, true, used, done, move(I.Direct rd, I.Direct rs)::instrs)
| loop([], false, _, done, instrs) = (done, instrs)
| loop([], true, _, done, instrs) =
loop(done, false, map #4 done, [], instrs)
fun cycle([], instrs) = instrs
| cycle(moves, instrs) =
(case loop(moves, false, map #4 moves, [], instrs)
of ([], instrs) => instrs
| ((rd, rd', rs, rs')::nonCyclic, instrs) => let
val SOME tmpR = tmp
val instrs' = move(tmpR, I.Direct rs)::instrs
val (cyclic, instrs'') =
loop(nonCyclic, false, map #4 nonCyclic, [], instrs')
in cycle(cyclic, move(I.Direct rd, Option.valOf tmp)::instrs'')
end
(*esac*))
fun rmCoalesced([], [], remain, coalesced) = (remain, coalesced)
| rmCoalesced(rd::rds, rs::rss, remain, coalesced) = let
val dst = lookup rd
val src = lookup rs
in
if dst = ~1 then (* eliminate dead copies *)
rmCoalesced(rds, rss, remain, coalesced)
else if dst = src then
rmCoalesced(rds, rss, remain,
move(I.Direct rd, I.Direct rs)::coalesced)
else rmCoalesced(rds, rss, (rd, dst, rs, src)::remain, coalesced)
end
in rev (cycle (rmCoalesced(dests, srcs, [], [])))
end
fun doBlock(F.BBLOCK{blknum, insns, liveOut, succ, ...}) = let
fun pseudoR r = (r >= 8 andalso r < firstPseudo)
fun resetLiveOut() = let
fun reset(gp, fp, cc) =
liveOut := (List.filter (not o pseudoR) gp, fp, cc)
in
case !succ
of [] => reset(!liveOut)
| [(F.EXIT _,_)] => reset(!liveOut)
| _ => ()
end
(* subst: hd(acc) is the last instruction in the stream. *)
fun subst(instr, acc) = let
fun mark(i,[]) = i
| mark(i,a::an) = mark(I.ANNOTATION{i=i,a=a},an)
fun movl{src, dst, acc} =
I.MOVE{mvOp=I.MOVL, src=src, dst=dst}::acc
fun displace(base, disp, acc, mem) =
let val base' = originalRegmap base
in if pseudoR base' then
let val tmpR = C.newReg()
val newDisp = I.Displace{base=tmpR, disp=disp, mem=mem}
in (newDisp, movl{src=ea base', dst=I.Direct tmpR, acc=acc})
end
else (I.Displace{base=base, disp=disp, mem=mem}, acc)
end
fun indexedEa(base, index, scale, disp, mem) =
I.Indexed{base=base, index=index, scale=scale, disp=disp, mem=mem}
fun indexed(NONE, index, scale, disp, acc, mem) =
let val index' = originalRegmap index
in if pseudoR index' then
let val tmpR = C.newReg()
val newIndx = indexedEa(NONE, tmpR, scale, disp, mem)
in (newIndx,movl{src=ea index', dst=I.Direct tmpR, acc=acc})
end
else (indexedEa(NONE, index, scale, disp, mem), acc)
end
| indexed(ba as SOME base, index, scale, disp, acc, mem) =
let val base' = originalRegmap base
val index' = originalRegmap index
val b = pseudoR base'
val i = pseudoR index'
in if b andalso i then
let val tmpB = C.newReg()
val tmpI = C.newReg()
val opnd = indexedEa(SOME tmpB, tmpI, scale, disp, mem)
in (opnd, movl{src=ea base', dst=I.Direct tmpB,
acc=movl{src=ea index',
dst=I.Direct tmpI, acc=acc}})
end
else if b then let
val tmpB = C.newReg()
in (indexedEa(SOME tmpB, index, scale, disp, mem),
movl{src=ea base', dst=I.Direct tmpB, acc=acc})
end
else if i then let
val tmpI = C.newReg()
in (indexedEa(ba, tmpI, scale, disp, mem),
movl{src=ea index', dst=I.Direct tmpI, acc=acc})
end
else (indexedEa(ba, index, scale, disp, mem), acc)
end
fun direct(r, acc) =
let val r' = originalRegmap r
in if pseudoR r' then (ea r', acc) else (I.Direct r, acc)
end
fun operand(I.Direct r, acc) = direct(r, acc)
| operand(I.Indexed{base, index, scale, disp, mem}, acc) =
indexed(base, index, scale, disp, acc, mem)
| operand(I.Displace{base, disp, mem}, acc) =
displace(base, disp, acc, mem)
| operand arg = arg
fun done(opnd, f, an) =
let val (opnd', acc') = operand(opnd, acc)
in mark(f opnd', an) :: acc'
end
fun memArg(I.Displace _) = true
| memArg(I.Indexed _) = true
| memArg(I.MemReg _) = true
| memArg(I.LabelEA _) = true
| memArg _ = false
fun withTmp f =
let val t = C.newReg()
in f t
end
fun rewriteCmpTest(cmptest, lsrc, rsrc, an) =
let val (lsrcOpnd, acc1) = operand(lsrc, acc)
val (rsrcOpnd, acc2) = operand(rsrc, acc1)
in if memArg lsrcOpnd andalso memArg rsrcOpnd then
withTmp(fn t =>
mark(cmptest{lsrc=I.Direct t, rsrc=rsrcOpnd},an)::
movl{src=lsrcOpnd, dst=I.Direct t, acc=acc2})
else
mark(cmptest{lsrc=lsrcOpnd, rsrc=rsrcOpnd},an)::acc2
end
fun rewrite(instr,an) =
case instr
of I.JMP(opnd, labs) => done(opnd,fn opnd => I.JMP(opnd, labs),an)
| I.JCC{opnd, cond} =>
done(opnd,fn opnd => I.JCC{opnd=opnd, cond=cond}, an)
| I.MOVE{src, dst, mvOp} => let
val (srcOpnd, acc1) = operand(src, acc)
val (dstOpnd, acc2) = operand(dst, acc1)
in
if memArg srcOpnd andalso memArg dstOpnd then
withTmp(fn t =>
mark(I.MOVE{src=I.Direct t, dst=dstOpnd, mvOp=mvOp},an)::
movl{src=srcOpnd, dst=I.Direct t, acc=acc2})
else
mark(I.MOVE{src=srcOpnd, dst=dstOpnd, mvOp=mvOp},an)::acc2
end
| I.LEA{r32, addr} => let
val (srcOpnd, acc1) = operand(addr, acc)
val r32' = originalRegmap r32
in
if pseudoR r32' then
withTmp(fn t =>
movl{dst=ea r32', src=I.Direct t,
acc=mark(I.LEA{r32=t, addr=srcOpnd},an)::acc1})
else mark(I.LEA{r32=r32, addr=srcOpnd},an)::acc1
end
| I.CMPL{lsrc, rsrc} => rewriteCmpTest(I.CMPL, lsrc, rsrc, an)
| I.CMPW{lsrc, rsrc} => rewriteCmpTest(I.CMPW, lsrc, rsrc, an)
| I.CMPB{lsrc, rsrc} => rewriteCmpTest(I.CMPB, lsrc, rsrc, an)
| I.TESTL{lsrc, rsrc} => rewriteCmpTest(I.TESTL, lsrc, rsrc, an)
| I.TESTW{lsrc, rsrc} => rewriteCmpTest(I.TESTW, lsrc, rsrc, an)
| I.TESTB{lsrc, rsrc} => rewriteCmpTest(I.TESTB, lsrc, rsrc, an)
| I.BINARY{binOp, src, dst} => let
val (srcOpnd, acc1) = operand(src, acc)
val (dstOpnd, acc2) = operand(dst, acc1)
in
if memArg srcOpnd andalso memArg dstOpnd then
withTmp(fn t =>
mark(I.BINARY{binOp=binOp,src=I.Direct t,dst=dstOpnd},an)::
movl{src=srcOpnd, dst=I.Direct t, acc=acc2})
else
mark(I.BINARY{binOp=binOp,src=srcOpnd,dst=dstOpnd},an)::acc2
end
| I.CALL(opnd,def,use,mem) => let
val (opnd1, acc1) = operand(opnd, acc)
fun cellset(gp, fp, cc) =
if pruneCellSets then
(List.filter (not o pseudoR) gp, fp, cc)
else
(gp, fp, cc)
in mark(I.CALL(opnd1, cellset def, cellset use, mem),an)::acc1
end
| I.MULTDIV{multDivOp, src} =>
done(src,
fn opnd => I.MULTDIV{multDivOp=multDivOp, src=opnd}, an)
| I.MUL3{dst, src1, src2} => let
val (src1Opnd, acc1) = operand(src1, acc)
val dst' = originalRegmap dst
in
if pseudoR dst' then
withTmp(fn t =>
movl{dst=ea dst', src=I.Direct t, acc=
mark(I.MUL3{dst=t, src1=src1Opnd, src2=src2},an)::acc1})
else mark(I.MUL3{dst=dst, src1=src1Opnd, src2=src2},an)::acc1
end
| I.UNARY{unOp, opnd} =>
done(opnd, fn opnd => I.UNARY{unOp=unOp, opnd=opnd}, an)
| I.SET{cond, opnd} =>
done(opnd, fn opnd => I.SET{cond=cond, opnd=opnd}, an)
| I.PUSHL opnd => done(opnd, I.PUSHL, an)
| I.PUSHW opnd => done(opnd, I.PUSHW, an)
| I.PUSHB opnd => done(opnd, I.PUSHB, an)
| I.POP opnd => done(opnd, I.POP, an)
| I.CMOV{cond, src, dst} =>
let val (srcOpnd, acc1) = operand(src, acc)
val dst' = originalRegmap dst
in if pseudoR dst then
withTmp(fn t =>
movl{dst=ea dst', src=I.Direct t, acc=
mark(I.CMOV{cond=cond, dst=t, src=srcOpnd},an)::
acc1})
else
mark(I.CMOV{cond=cond, dst=dst, src=srcOpnd},an)::acc1
end
| I.COPY{dst, src, tmp} => let
(* Note:
* Parallel copies are not allowed after this point.
* Consider:
* (r8, r9, edx) <- (566, 567, 560)
*
* RA32 may well decide to allocate 560 to r8.
* After the rewrite we will get:
*
* mem[r8] <- 566
* mem[r9] <- 567
* edx <- 560
*
* If 560 should spill, we all of a sudden have the
* incorrect value being read from the spill location.
*)
fun f((instr as I.MOVE{mvOp, src, dst})::rest, acc) =
(case (src, dst)
of (I.Direct s, I.Direct d) =>
let val d' = originalRegmap d
val s' = originalRegmap s
in if s'=d' then f(rest, acc)
else if pseudoR d' andalso pseudoR s' then
f(rest, withTmp(fn t =>
(movl{src=I.Direct t, dst=ea d',
acc=movl{src=ea s',
dst=I.Direct t, acc=acc}})))
else if pseudoR d' then
f(rest, withTmp(fn t =>
(movl{src=I.Direct s, dst=ea d', acc=acc})))
else if pseudoR s' then
f(rest, withTmp(fn t =>
(movl{src=ea s', dst=I.Direct d, acc=acc})))
else f(rest,I.COPY{src=[s], dst=[d],tmp=NONE}::acc)
end
| _ => f(rest, instr::acc)
(*esac*))
| f([], acc) = acc
in f(shuffle (dst, src, tmp), acc)
end
| I.FSTPT opnd => done(opnd, I.FSTPT, an)
| I.FSTPL opnd => done(opnd, I.FSTPL, an)
| I.FSTPS opnd => done(opnd, I.FSTPS, an)
| I.FSTL opnd => done(opnd, I.FSTL, an)
| I.FSTS opnd => done(opnd, I.FSTS, an)
| I.FLDT opnd => done(opnd, I.FLDT, an)
| I.FLDL opnd => done(opnd, I.FLDL, an)
| I.FLDS opnd => done(opnd, I.FLDS, an)
| I.FILD opnd => done(opnd, I.FILD, an)
| I.FILDL opnd => done(opnd, I.FILDL, an)
| I.FILDLL opnd => done(opnd, I.FILDLL, an)
| I.FENV{fenvOp, opnd} => done(opnd,
fn opnd => I.FENV{fenvOp=fenvOp,opnd=opnd}, an)
| I.FBINARY{src,dst,binOp} =>
done(src,
fn opnd => I.FBINARY{binOp=binOp, src=opnd, dst=dst},an)
| I.FIBINARY{src,binOp} =>
done(src, fn opnd => I.FIBINARY{binOp=binOp, src=opnd},an)
| I.ANNOTATION{i,a} => rewrite(i,a::an)
| _ => mark(instr,an)::acc
in rewrite(instr,[])
end (* subst *)
in insns := List.foldl subst [] (rev(!insns));
if pruneCellSets then resetLiveOut() else ()
end (*doBlock*)
| doBlock _ = ()
in app doBlock blocks; (first, C.newReg())
end (* rewrite *)
end
|
