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|
(*
* This is my E-compressed DJ-graph data structure
* --Allen
*)
functor E_DJGraph (Dom : DOMINATOR_TREE) : DJ_GRAPH =
struct
structure G = Graph
structure Dom = Dom
structure A = Array
fun error msg = MLRiscErrorMsg.error("E-DJGraph",msg)
val stats = false (* collect statistics? *)
val visitCount = MLRiscControl.getCounter "dj-visit-count"
val idfCount = MLRiscControl.getCounter "dj-IDF-count"
val idfSize = MLRiscControl.getCounter "dj-IDF-size"
val liveVisitCount = MLRiscControl.getCounter "dj-live-visit-count"
datatype tree = NODE of int * tree list
datatype ('n,'e,'g) dj_graph =
DJGRAPH of
{ dom : ('n,'e,'g) Dom.dominator_tree,
trees : tree option A.array,
jedges : int list A.array
}
fun DJ(Dom as G.GRAPH dom) =
let val G.GRAPH cfg = Dom.cfg Dom
val L = Dom.max_levels Dom
val N = #capacity dom ()
val levelsMap = Dom.levelsMap Dom
val rank_J = A.array(N, 0)
val trees = A.array(N, NONE)
val jedges = A.array(N, [])
val buckets = A.array(L, [])
fun ExitTrees a =
let fun foreachDedge [] = ()
| foreachDedge((_,b,_)::es) = (ExitTrees b; foreachDedge es)
val _ = foreachDedge (#out_edges dom a)
val lvl_a = A.sub(levelsMap, a)
fun foreachJedge([], rank) = A.update(rank_J,a,rank)
| foreachJedge((a,b,_)::es, rank) =
let val lvl_b = A.sub(levelsMap, b)
in if lvl_b <= lvl_a then
foreachJedge(es, if lvl_b < rank then lvl_b else rank)
else
foreachJedge(es, rank)
end
val _ = foreachJedge (#out_edges cfg a, L+1)
fun buildTree([], succ) = NODE(a,succ)
| buildTree((_,b,_)::es, succ) =
(case A.sub(trees, b) of
NONE => buildTree(es, succ)
| SOME t => buildTree(es, t::succ)
)
val t_a = buildTree(#out_edges dom a, [])
in A.update(trees, a, pruneTree(A.sub(levelsMap, a), t_a))
end
and pruneTree(lvl_a, NODE(x,succ)) =
let fun foreachSucc([], subtrees) = subtrees
| foreachSucc(t::ts, subtrees) =
foreachSucc(ts,
case pruneTree(lvl_a, t) of
NONE => subtrees
| SOME t => t::subtrees
)
val subtrees = foreachSucc(succ, [])
in case (A.sub(rank_J,x) <= lvl_a, subtrees) of
(false,[]) => NONE
| (false,[t]) => SOME t
| (_,ts) => SOME(NODE(x,ts))
end
fun fillJedges l =
if l < 0 then () else
let fun fill [] = ()
| fill ((a,b)::es) =
(A.update(jedges, a, b::A.sub(jedges, a)); fill es)
in fill(A.sub(buckets, l));
fillJedges(l-1)
end
val [ENTRY] = #entries dom ()
in ExitTrees ENTRY;
fillJedges(L-1);
DJGRAPH{dom=Dom, trees=trees, jedges=jedges}
end
(* Compute dominance frontier *)
fun DF _ = error "DF"
(* Compute iterated dominance frontier *)
fun IDFs _ = error "IDFs"
(* Compute iterated dominance frontier with liveness *)
fun LiveIDFs(DJGRAPH{dom=Dom as G.GRAPH dom, jedges, trees}) =
let val G.GRAPH cfg = Dom.cfg Dom
val L = Dom.max_levels Dom
val N = #capacity dom ()
val levels = Dom.levelsMap Dom
val in_phi = A.array(N,0) (* has appeared in the DF set? *)
val liveIn = A.array(N,0)
val stamp = ref 0
fun new_stamp() = let val s = !stamp + 1 in stamp := s; s end
val in_alpha = A.array(N,0) (* has appeared in N_alpha? *)
val visited = A.array(N,0) (* has it been visited *)
val piggybank = A.array(L,[]) (* nodes in the piggy bank *)
fun LiveIDFs{defs=xs, localLiveIn=[]} = []
| LiveIDFs{defs=xs, localLiveIn} =
let val stamp = new_stamp()
val _ = if stats then idfCount := !idfCount + 1 else ()
fun init([],l) = l
| init(x::xs,l) =
let val l_x = A.sub(levels,x)
in A.update(in_alpha,x,stamp);
A.update(piggybank,l_x,x::A.sub(piggybank,l_x));
init(xs,if l < l_x then l_x else l)
end
fun markLiveIn(b) =
let fun markPred [] = ()
| markPred((j,_,_)::es) =
(if A.sub(liveIn,j) <> stamp andalso
A.sub(in_alpha,j) <> stamp then
markLiveIn j
else ();
markPred es
)
in A.update(liveIn,b,stamp);
if stats then liveVisitCount := !liveVisitCount + 1 else ();
markPred(#in_edges cfg b)
end
fun initLiveIn [] = ()
| initLiveIn(x::xs) = (markLiveIn x; initLiveIn xs)
fun isLive b = A.sub(liveIn,b) = stamp
fun visit(x,S) =
case A.sub(trees,x) of
NONE => S
| SOME t => walk(t,A.sub(levels,x),S)
and walk(NODE(y,succ_y),level_x,S) =
if A.sub(visited,y) <> stamp then
let val _ = A.update(visited,y,stamp)
fun foreachJedge([],S) = S
| foreachJedge(z::zs,S) =
let val level_z = A.sub(levels,z)
in if level_z <= level_x then
if isLive z andalso A.sub(in_phi,z) <> stamp
(* z is a new IDF^+ candidate;
* make sure it is live.
*)
then (A.update(in_phi,z,stamp);
if A.sub(in_alpha,z) <> stamp
then A.update(piggybank,level_z,
z::A.sub(piggybank,level_z))
else ();
foreachJedge(zs,z::S)
)
else foreachJedge(zs,S)
else S
end
fun foreachEedge([], S) = S
| foreachEedge((t as NODE(z,_))::ts,S) =
foreachEedge(ts,if isLive z then walk(t,level_x,S) else S)
val _ = if stats then visitCount := !visitCount + 1 else ();
in foreachEedge(succ_y, foreachJedge(A.sub(jedges, y),S))
end
else S
fun visitAll(~1,S) = S
| visitAll(l,S) =
case A.sub(piggybank,l) of
[] => visitAll(l-1,S)
| x::xs => (A.update(piggybank,l,xs);
visitAll(l,visit(x,S)))
val L = init(xs,~1)
val _ = initLiveIn localLiveIn
val IDF = visitAll(L,[])
in if stats then idfSize := !idfSize + length IDF else ();
IDF
end
in LiveIDFs
end
end
|
