HCoop / hcoop / debian / mlton.git / blame
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| 7f918cf1 CE |
1 | (* Copyright (C) 2017 Matthew Fluet. |
| 2 | * Copyright (C) 1999-2008 Henry Cejtin, Matthew Fluet, Suresh | |
| 3 | * Jagannathan, and Stephen Weeks. | |
| 4 | * Copyright (C) 1997-2000 NEC Research Institute. | |
| 5 | * | |
| 6 | * MLton is released under a BSD-style license. | |
| 7 | * See the file MLton-LICENSE for details. | |
| 8 | *) | |
| 9 | ||
| 10 | (* | |
| 11 | * Invariant: Created globals only refer to other globals. | |
| 12 | * Hence, the newly created globals may appear at the | |
| 13 | * beginning of the program. | |
| 14 | * | |
| 15 | * Circular abstract values can arise as a result of programs like: | |
| 16 | * datatype t = T of t | |
| 17 | * fun f () = T (f ()) | |
| 18 | * val _ = f () | |
| 19 | * There is special code in printing abstract values and in determining whether | |
| 20 | * they are global in order to avoid infinite loops. | |
| 21 | *) | |
| 22 | ||
| 23 | functor ConstantPropagation (S: SSA_TRANSFORM_STRUCTS) : SSA_TRANSFORM = | |
| 24 | struct | |
| 25 | ||
| 26 | open S | |
| 27 | ||
| 28 | structure Multi = Multi (S) | |
| 29 | structure Global = Global (S) | |
| 30 | ||
| 31 | structure Type = | |
| 32 | struct | |
| 33 | open Type | |
| 34 | ||
| 35 | fun isSmall t = | |
| 36 | case dest t of | |
| 37 | Array _ => false | |
| 38 | | Datatype _ => false | |
| 39 | | Ref t => isSmall t | |
| 40 | | Tuple ts => Vector.forall (ts, isSmall) | |
| 41 | | Vector _ => false | |
| 42 | | _ => true | |
| 43 | end | |
| 44 | ||
| 45 | structure Sconst = Const | |
| 46 | open Exp Transfer | |
| 47 | ||
| 48 | structure Value = | |
| 49 | struct | |
| 50 | datatype global = | |
| 51 | NotComputed | |
| 52 | | No | |
| 53 | | Yes of Var.t | |
| 54 | ||
| 55 | structure Const = | |
| 56 | struct | |
| 57 | datatype t = T of {const: const ref, | |
| 58 | coercedTo: t list ref} | |
| 59 | and const = | |
| 60 | Const of Const.t | |
| 61 | | Undefined (* no possible value *) | |
| 62 | | Unknown (* many possible values *) | |
| 63 | ||
| 64 | fun layout (T {const, ...}) = layoutConst (!const) | |
| 65 | and layoutConst c = | |
| 66 | let | |
| 67 | open Layout | |
| 68 | in | |
| 69 | case c of | |
| 70 | Const c => Const.layout c | |
| 71 | | Undefined => str "undefined constant" | |
| 72 | | Unknown => str "unknown constant" | |
| 73 | end | |
| 74 | ||
| 75 | fun new c = T {const = ref c, | |
| 76 | coercedTo = ref []} | |
| 77 | ||
| 78 | fun equals (T {const = r, ...}, T {const = r', ...}) = r = r' | |
| 79 | ||
| 80 | val equals = | |
| 81 | Trace.trace2 | |
| 82 | ("ConstantPropagation.Value.Const.equals", | |
| 83 | layout, layout, Bool.layout) | |
| 84 | equals | |
| 85 | ||
| 86 | val const = new o Const | |
| 87 | ||
| 88 | fun undefined () = new Undefined | |
| 89 | ||
| 90 | fun unknown () = new Unknown | |
| 91 | ||
| 92 | fun makeUnknown (T {const, coercedTo}): unit = | |
| 93 | case !const of | |
| 94 | Unknown => () | |
| 95 | | _ => (const := Unknown | |
| 96 | ; List.foreach (!coercedTo, makeUnknown) | |
| 97 | ; coercedTo := []) | |
| 98 | ||
| 99 | val makeUnknown = | |
| 100 | Trace.trace | |
| 101 | ("ConstantPropagation.Value.Const.makeUnknown", | |
| 102 | layout, Unit.layout) | |
| 103 | makeUnknown | |
| 104 | ||
| 105 | fun send (c: t, c': const): unit = | |
| 106 | let | |
| 107 | fun loop (c as T {const, coercedTo}) = | |
| 108 | case (c', !const) of | |
| 109 | (_, Unknown) => () | |
| 110 | | (_, Undefined) => (const := c' | |
| 111 | ; List.foreach (!coercedTo, loop)) | |
| 112 | | (Const c', Const c'') => | |
| 113 | if Const.equals (c', c'') | |
| 114 | then () | |
| 115 | else makeUnknown c | |
| 116 | | _ => makeUnknown c | |
| 117 | in | |
| 118 | loop c | |
| 119 | end | |
| 120 | ||
| 121 | val send = | |
| 122 | Trace.trace2 | |
| 123 | ("ConstantPropagation.Value.Const.send", | |
| 124 | layout, layoutConst, Unit.layout) | |
| 125 | send | |
| 126 | ||
| 127 | fun coerce {from = from as T {const, coercedTo}, to: t}: unit = | |
| 128 | if equals (from, to) | |
| 129 | then () | |
| 130 | else | |
| 131 | let | |
| 132 | fun push () = List.push (coercedTo, to) | |
| 133 | in | |
| 134 | case !const of | |
| 135 | c as Const _ => (push (); send (to, c)) | |
| 136 | | Undefined => push () | |
| 137 | | Unknown => makeUnknown to | |
| 138 | end | |
| 139 | ||
| 140 | val coerce = | |
| 141 | Trace.trace | |
| 142 | ("ConstantPropagation.Value.Const.coerce", | |
| 143 | fn {from, to} => Layout.record [("from", layout from), | |
| 144 | ("to", layout to)], | |
| 145 | Unit.layout) | |
| 146 | coerce | |
| 147 | ||
| 148 | fun unify (c, c') = | |
| 149 | (coerce {from = c, to = c'} | |
| 150 | ; coerce {from = c', to = c}) | |
| 151 | ||
| 152 | val unify = | |
| 153 | Trace.trace2 | |
| 154 | ("ConstantPropagation.Value.Const.unify", | |
| 155 | layout, layout, Unit.layout) | |
| 156 | unify | |
| 157 | end | |
| 158 | ||
| 159 | structure One = | |
| 160 | struct | |
| 161 | datatype 'a t = T of {extra: 'a, | |
| 162 | global: Var.t option ref} | |
| 163 | ||
| 164 | local | |
| 165 | fun make f (T r) = f r | |
| 166 | in | |
| 167 | val global = fn z => make #global z | |
| 168 | end | |
| 169 | ||
| 170 | fun layout (one: 'a t): Layout.t = | |
| 171 | Layout.record | |
| 172 | [("global", Option.layout Var.layout (! (global one)))] | |
| 173 | ||
| 174 | fun new (a: 'a): 'a t = T {extra = a, | |
| 175 | global = ref NONE} | |
| 176 | ||
| 177 | val equals: 'a t * 'a t -> bool = | |
| 178 | fn (n, n') => global n = global n' | |
| 179 | end | |
| 180 | ||
| 181 | structure Place = | |
| 182 | struct | |
| 183 | datatype 'a t = | |
| 184 | One of 'a One.t | |
| 185 | | Undefined | |
| 186 | | Unknown | |
| 187 | ||
| 188 | val toString = | |
| 189 | fn One _ => "One" | |
| 190 | | Undefined => "Undefined" | |
| 191 | | Unknown => "Unknown" | |
| 192 | ||
| 193 | fun layout b = Layout.str (toString b) | |
| 194 | end | |
| 195 | ||
| 196 | structure Birth = | |
| 197 | struct | |
| 198 | datatype 'a t = T of {coercedTo: 'a t list ref, | |
| 199 | place: 'a Place.t ref} | |
| 200 | ||
| 201 | fun layout (T {place, ...}) = Place.layout (!place) | |
| 202 | ||
| 203 | fun equals (T {place = r, ...}, T {place = r', ...}) = r = r' | |
| 204 | ||
| 205 | fun new p = T {place = ref p, | |
| 206 | coercedTo = ref []} | |
| 207 | ||
| 208 | fun undefined (): 'a t = new Place.Undefined | |
| 209 | fun unknown (): 'a t = new Place.Unknown | |
| 210 | fun here (a: 'a): 'a t = new (Place.One (One.new a)) | |
| 211 | ||
| 212 | val traceMakeUnknown = | |
| 213 | Trace.info | |
| 214 | "ConstantPropagation.Value.Birth.makeUnknown" | |
| 215 | ||
| 216 | fun makeUnknown arg = | |
| 217 | Trace.traceInfo' | |
| 218 | (traceMakeUnknown, layout, Unit.layout) | |
| 219 | (fn T {place, coercedTo, ...} => | |
| 220 | case !place of | |
| 221 | Place.Unknown => () | |
| 222 | | _ => (place := Place.Unknown | |
| 223 | ; List.foreach (!coercedTo, makeUnknown) | |
| 224 | ; coercedTo := [])) arg | |
| 225 | ||
| 226 | val traceSend = | |
| 227 | Trace.info | |
| 228 | "ConstantPropagation.Value.Birth.send" | |
| 229 | ||
| 230 | fun send arg = | |
| 231 | Trace.traceInfo' | |
| 232 | (traceSend, Layout.tuple2 (layout, One.layout), Unit.layout) | |
| 233 | (fn (b, one) => | |
| 234 | let | |
| 235 | fun loop (b as T {place, coercedTo, ...}) = | |
| 236 | case !place of | |
| 237 | Place.Undefined => (place := Place.One one | |
| 238 | ; List.foreach (!coercedTo, loop)) | |
| 239 | | Place.One one' => if One.equals (one, one') | |
| 240 | then () | |
| 241 | else makeUnknown b | |
| 242 | | Place.Unknown => () | |
| 243 | in | |
| 244 | loop b | |
| 245 | end) arg | |
| 246 | ||
| 247 | val traceCoerce = | |
| 248 | Trace.info | |
| 249 | "ConstantPropagation.Value.Birth.coerce" | |
| 250 | fun coerce arg = | |
| 251 | Trace.traceInfo' | |
| 252 | (traceCoerce, | |
| 253 | fn {from, to} => Layout.record [("from", layout from), | |
| 254 | ("to", layout to)], | |
| 255 | Unit.layout) | |
| 256 | (fn {from = from as T {place, coercedTo, ...}, to} => | |
| 257 | if equals (from, to) | |
| 258 | then () | |
| 259 | else | |
| 260 | let | |
| 261 | fun push () = List.push (coercedTo, to) | |
| 262 | in | |
| 263 | case !place of | |
| 264 | Place.Unknown => makeUnknown to | |
| 265 | | Place.One one => (push (); send (to, one)) | |
| 266 | | Place.Undefined => push () | |
| 267 | end) arg | |
| 268 | ||
| 269 | val traceUnify = | |
| 270 | Trace.info | |
| 271 | "ConstantPropagation.Value.Birth.unify" | |
| 272 | ||
| 273 | fun unify arg = | |
| 274 | Trace.traceInfo' | |
| 275 | (traceUnify, Layout.tuple2 (layout, layout), Unit.layout) | |
| 276 | (fn (c, c') => | |
| 277 | (coerce {from = c, to = c'} | |
| 278 | ; coerce {from = c', to = c})) arg | |
| 279 | end | |
| 280 | ||
| 281 | structure Set = DisjointSet | |
| 282 | structure Unique = UniqueId () | |
| 283 | ||
| 284 | datatype t = | |
| 285 | T of {global: global ref, | |
| 286 | ty: Type.t, | |
| 287 | value: value} Set.t | |
| 288 | and value = | |
| 289 | Array of {birth: unit Birth.t, | |
| 290 | elt: t, | |
| 291 | length: t, | |
| 292 | raw: bool option ref} | |
| 293 | | Const of Const.t | |
| 294 | | Datatype of data | |
| 295 | | Ref of {arg: t, | |
| 296 | birth: {init: t} Birth.t} | |
| 297 | | Tuple of t vector | |
| 298 | | Vector of {elt: t, | |
| 299 | length: t} | |
| 300 | | Weak of t | |
| 301 | and data = | |
| 302 | Data of {coercedTo: data list ref, | |
| 303 | filters: {args: t vector, | |
| 304 | con: Con.t} list ref, | |
| 305 | value: dataVal ref} | |
| 306 | and dataVal = | |
| 307 | ConApp of {args: t vector, | |
| 308 | con: Con.t, | |
| 309 | uniq: Unique.t} | |
| 310 | | Undefined | |
| 311 | | Unknown | |
| 312 | ||
| 313 | local | |
| 314 | fun make sel (T s) = sel (Set.! s) | |
| 315 | in | |
| 316 | val value = make #value | |
| 317 | val ty = make #ty | |
| 318 | end | |
| 319 | fun deConst v = | |
| 320 | case value v of | |
| 321 | Const (Const.T {const, ...}) => | |
| 322 | (case !const of | |
| 323 | Const.Const c => SOME c | |
| 324 | | _ => NONE) | |
| 325 | | _ => NONE | |
| 326 | ||
| 327 | local | |
| 328 | open Layout | |
| 329 | in | |
| 330 | fun layout v = | |
| 331 | case value v of | |
| 332 | Array {birth, elt, length, raw, ...} => | |
| 333 | seq [str "array", tuple [Birth.layout birth, | |
| 334 | layout length, | |
| 335 | layout elt, | |
| 336 | Option.layout Bool.layout (!raw)]] | |
| 337 | | Const c => Const.layout c | |
| 338 | | Datatype d => layoutData d | |
| 339 | | Ref {arg, birth, ...} => | |
| 340 | seq [str "ref ", tuple [layout arg, Birth.layout birth]] | |
| 341 | | Tuple vs => Vector.layout layout vs | |
| 342 | | Vector {elt, length, ...} => seq [str "vector ", | |
| 343 | tuple [layout elt, | |
| 344 | layout length]] | |
| 345 | | Weak v => seq [str "weak ", layout v] | |
| 346 | and layoutData (Data {value, ...}) = | |
| 347 | case !value of | |
| 348 | Undefined => str "undefined datatype" | |
| 349 | | ConApp {con, uniq, ...} => | |
| 350 | record [("con", Con.layout con), | |
| 351 | ("uniq", Unique.layout uniq)] | |
| 352 | (* Can't layout the args because there may be a circularity *) | |
| 353 | | Unknown => str "unknown datatype" | |
| 354 | end | |
| 355 | ||
| 356 | fun equals (T s, T s') = Set.equals (s, s') | |
| 357 | ||
| 358 | val equals = | |
| 359 | Trace.trace2 | |
| 360 | ("ConstantPropagation.Value.equals", | |
| 361 | layout, layout, Bool.layout) | |
| 362 | equals | |
| 363 | ||
| 364 | val globalsInfo = Trace.info "ConstantPropagation.Value.globals" | |
| 365 | val globalInfo = Trace.info "ConstantPropagation.Value.global" | |
| 366 | ||
| 367 | fun globals arg: (Var.t * Type.t) vector option = | |
| 368 | Trace.traceInfo | |
| 369 | (globalsInfo, | |
| 370 | (Vector.layout layout) o #1, | |
| 371 | Option.layout (Vector.layout | |
| 372 | (Layout.tuple2 (Var.layout, Type.layout))), | |
| 373 | Trace.assertTrue) | |
| 374 | (fn (vs: t vector, newGlobal) => | |
| 375 | Exn.withEscape | |
| 376 | (fn escape => | |
| 377 | SOME (Vector.map | |
| 378 | (vs, fn v => | |
| 379 | case global (v, newGlobal) of | |
| 380 | NONE => escape NONE | |
| 381 | | SOME g => g)))) arg | |
| 382 | and global arg: (Var.t * Type.t) option = | |
| 383 | Trace.traceInfo (globalInfo, | |
| 384 | layout o #1, | |
| 385 | Option.layout (Var.layout o #1), | |
| 386 | Trace.assertTrue) | |
| 387 | (fn (v as T s, newGlobal) => | |
| 388 | let val {global = r, ty, value} = Set.! s | |
| 389 | in case !r of | |
| 390 | No => NONE | |
| 391 | | Yes g => SOME (g, ty) | |
| 392 | | NotComputed => | |
| 393 | let | |
| 394 | (* avoid globalizing circular abstract values *) | |
| 395 | val _ = r := No | |
| 396 | fun yes e = Yes (newGlobal (ty, e)) | |
| 397 | fun unary (Birth.T {place, ...}, | |
| 398 | makeInit: 'a -> t, | |
| 399 | primApp: {targs: Type.t vector, | |
| 400 | args: Var.t vector} -> Exp.t, | |
| 401 | targ: Type.t) = | |
| 402 | case !place of | |
| 403 | Place.One (One.T {global = glob, extra, ...}) => | |
| 404 | let | |
| 405 | val init = makeInit extra | |
| 406 | in | |
| 407 | case global (init, newGlobal) of | |
| 408 | SOME (x, _) => | |
| 409 | Yes | |
| 410 | (case !glob of | |
| 411 | NONE => | |
| 412 | let | |
| 413 | val exp = | |
| 414 | primApp | |
| 415 | {targs = Vector.new1 targ, | |
| 416 | args = Vector.new1 x} | |
| 417 | val g = newGlobal (ty, exp) | |
| 418 | in | |
| 419 | glob := SOME g; g | |
| 420 | end | |
| 421 | | SOME g => g) | |
| 422 | | _ => No | |
| 423 | end | |
| 424 | | _ => No | |
| 425 | val g = | |
| 426 | case value of | |
| 427 | Array {birth, length, raw, ...} => | |
| 428 | unary (birth, fn _ => length, | |
| 429 | fn {args, targs} => | |
| 430 | Exp.PrimApp {args = args, | |
| 431 | prim = Prim.arrayAlloc | |
| 432 | {raw = valOf (!raw)}, | |
| 433 | targs = targs}, | |
| 434 | Type.deArray ty) | |
| 435 | | Const (Const.T {const, ...}) => | |
| 436 | (case !const of | |
| 437 | Const.Const c => yes (Exp.Const c) | |
| 438 | | _ => No) | |
| 439 | | Datatype (Data {value, ...}) => | |
| 440 | (case !value of | |
| 441 | ConApp {args, con, ...} => | |
| 442 | (case globals (args, newGlobal) of | |
| 443 | NONE => No | |
| 444 | | SOME args => | |
| 445 | yes (Exp.ConApp | |
| 446 | {con = con, | |
| 447 | args = Vector.map (args, #1)})) | |
| 448 | | _ => No) | |
| 449 | | Ref {birth, ...} => | |
| 450 | unary (birth, fn {init} => init, | |
| 451 | fn {args, targs} => | |
| 452 | Exp.PrimApp {args = args, | |
| 453 | prim = Prim.reff, | |
| 454 | targs = targs}, | |
| 455 | Type.deRef ty) | |
| 456 | | Tuple vs => | |
| 457 | (case globals (vs, newGlobal) of | |
| 458 | NONE => No | |
| 459 | | SOME xts => | |
| 460 | yes (Exp.Tuple (Vector.map (xts, #1)))) | |
| 461 | | Vector {elt, length} => | |
| 462 | (case Option.map (deConst length, S.Const.deWord) of | |
| 463 | NONE => No | |
| 464 | | SOME length => | |
| 465 | let | |
| 466 | val length = WordX.toInt length | |
| 467 | val eltTy = Type.deVector ty | |
| 468 | fun mkVec args = | |
| 469 | yes (Exp.PrimApp | |
| 470 | {args = args, | |
| 471 | prim = Prim.vector, | |
| 472 | targs = Vector.new1 eltTy}) | |
| 473 | fun mkConst (ws, elts) = | |
| 474 | yes (Exp.Const | |
| 475 | (S.Const.wordVector | |
| 476 | (WordXVector.fromList | |
| 477 | ({elementSize = ws}, elts)))) | |
| 478 | in | |
| 479 | case (Option.map (deConst elt, S.Const.deWordOpt), | |
| 480 | global (elt, newGlobal)) of | |
| 481 | (SOME (SOME w), _) => | |
| 482 | mkConst (Type.deWord eltTy, | |
| 483 | List.new (length, w)) | |
| 484 | | (_, SOME (x, _)) => | |
| 485 | mkVec (Vector.new (length, x)) | |
| 486 | | _ => | |
| 487 | if length = 0 | |
| 488 | then case Type.deWordOpt eltTy of | |
| 489 | SOME ws => mkConst (ws, []) | |
| 490 | | NONE => mkVec (Vector.new0 ()) | |
| 491 | else No | |
| 492 | end) | |
| 493 | | Weak _ => No | |
| 494 | val _ = r := g | |
| 495 | in | |
| 496 | global (v, newGlobal) | |
| 497 | end | |
| 498 | end) arg | |
| 499 | ||
| 500 | fun new (v: value, ty: Type.t): t = | |
| 501 | T (Set.singleton {value = v, | |
| 502 | ty = ty, | |
| 503 | global = ref NotComputed}) | |
| 504 | ||
| 505 | fun tuple vs = | |
| 506 | new (Tuple vs, Type.tuple (Vector.map (vs, ty))) | |
| 507 | ||
| 508 | fun const' (c, ty) = new (Const c, ty) | |
| 509 | ||
| 510 | fun const c = let val c' = Const.const c | |
| 511 | in new (Const c', Type.ofConst c) | |
| 512 | end | |
| 513 | ||
| 514 | fun constToEltLength (c, err) = | |
| 515 | let | |
| 516 | val v = | |
| 517 | case c of | |
| 518 | Sconst.WordVector v => v | |
| 519 | | _ => Error.bug err | |
| 520 | val length = WordXVector.length v | |
| 521 | val eltTy = Type.word (WordXVector.elementSize v) | |
| 522 | val elt = | |
| 523 | if 0 = length | |
| 524 | then const' (Const.unknown (), eltTy) | |
| 525 | else let | |
| 526 | val w = WordXVector.sub (v, 0) | |
| 527 | in | |
| 528 | if WordXVector.forall (v, fn w' => | |
| 529 | WordX.equals (w, w')) | |
| 530 | then const (Sconst.word w) | |
| 531 | else const' (Const.unknown (), eltTy) | |
| 532 | end | |
| 533 | val length = | |
| 534 | const (Sconst.Word (WordX.fromIntInf (IntInf.fromInt length, | |
| 535 | WordSize.seqIndex ()))) | |
| 536 | in | |
| 537 | {elt = elt, length = length} | |
| 538 | end | |
| 539 | ||
| 540 | local | |
| 541 | fun make (err, sel) v = | |
| 542 | case value v of | |
| 543 | Vector fs => sel fs | |
| 544 | | Const (Const.T {const = ref (Const.Const c), ...}) => | |
| 545 | sel (constToEltLength (c, err)) | |
| 546 | | _ => Error.bug err | |
| 547 | in | |
| 548 | val devector = make ("ConstantPropagation.Value.devector", #elt) | |
| 549 | val vectorLength = make ("ConstantPropagation.Value.vectorLength", #length) | |
| 550 | end | |
| 551 | ||
| 552 | local | |
| 553 | fun make (err, sel) v = | |
| 554 | case value v of | |
| 555 | Array fs => sel fs | |
| 556 | | _ => Error.bug err | |
| 557 | in val dearray = make ("ConstantPropagation.Value.dearray", #elt) | |
| 558 | val arrayLength = make ("ConstantPropagation.Value.arrayLength", #length) | |
| 559 | val arrayBirth = make ("ConstantPropagation.Value.arrayBirth", #birth) | |
| 560 | val arrayRaw = make ("ConstantPropagation.Value.arrayRaw", #raw) | |
| 561 | end | |
| 562 | ||
| 563 | fun arrayFromArray (T s: t): t = | |
| 564 | let | |
| 565 | val {value, ty, ...} = Set.! s | |
| 566 | in case value of | |
| 567 | Array {elt, length, ...} => | |
| 568 | new (Array {birth = Birth.unknown (), elt = elt, length = length, raw = ref (SOME false)}, ty) | |
| 569 | | _ => Error.bug "ConstantPropagation.Value.arrayFromArray" | |
| 570 | end | |
| 571 | ||
| 572 | fun vectorFromArray (T s: t): t = | |
| 573 | let | |
| 574 | val {value, ty, ...} = Set.! s | |
| 575 | in case value of | |
| 576 | Array {elt, length, ...} => | |
| 577 | new (Vector {elt = elt, length = length}, Type.vector (Type.deArray ty)) | |
| 578 | | _ => Error.bug "ConstantPropagation.Value.vectorFromArray" | |
| 579 | end | |
| 580 | ||
| 581 | local | |
| 582 | fun make (err, sel) v = | |
| 583 | case value v of | |
| 584 | Ref fs => sel fs | |
| 585 | | _ => Error.bug err | |
| 586 | in | |
| 587 | val deref = make ("ConstantPropagation.Value.deref", #arg) | |
| 588 | val refBirth = make ("ConstantPropagation.Value.refBirth", #birth) | |
| 589 | end | |
| 590 | ||
| 591 | fun deweak v = | |
| 592 | case value v of | |
| 593 | Weak v => v | |
| 594 | | _ => Error.bug "ConstantPropagation.Value.deweak" | |
| 595 | ||
| 596 | structure Data = | |
| 597 | struct | |
| 598 | datatype t = datatype data | |
| 599 | ||
| 600 | val layout = layoutData | |
| 601 | ||
| 602 | local | |
| 603 | fun make v () = Data {value = ref v, | |
| 604 | coercedTo = ref [], | |
| 605 | filters = ref []} | |
| 606 | in | |
| 607 | val undefined = make Undefined | |
| 608 | val unknown = make Unknown | |
| 609 | end | |
| 610 | end | |
| 611 | ||
| 612 | local | |
| 613 | (* The extra birth is because of let-style polymorphism. | |
| 614 | * arrayBirth is really the same as refBirth. | |
| 615 | *) | |
| 616 | fun make (const, data, refBirth, arrayBirth) = | |
| 617 | let | |
| 618 | fun loop (t: Type.t): t = | |
| 619 | new | |
| 620 | (case Type.dest t of | |
| 621 | Type.Array t => | |
| 622 | Array {birth = arrayBirth (), | |
| 623 | elt = loop t, | |
| 624 | length = loop (Type.word (WordSize.seqIndex ())), | |
| 625 | raw = ref NONE} | |
| 626 | | Type.Datatype _ => Datatype (data ()) | |
| 627 | | Type.Ref t => Ref {arg = loop t, | |
| 628 | birth = refBirth ()} | |
| 629 | | Type.Tuple ts => Tuple (Vector.map (ts, loop)) | |
| 630 | | Type.Vector t => Vector | |
| 631 | {elt = loop t, | |
| 632 | length = loop (Type.word (WordSize.seqIndex ()))} | |
| 633 | | Type.Weak t => Weak (loop t) | |
| 634 | | _ => Const (const ()), | |
| 635 | t) | |
| 636 | in loop | |
| 637 | end | |
| 638 | in | |
| 639 | val fromType = | |
| 640 | make (Const.undefined, | |
| 641 | Data.undefined, | |
| 642 | Birth.undefined, | |
| 643 | Birth.undefined) | |
| 644 | val unknown = | |
| 645 | make (Const.unknown, | |
| 646 | Data.unknown, | |
| 647 | Birth.unknown, | |
| 648 | Birth.unknown) | |
| 649 | end | |
| 650 | ||
| 651 | fun select {tuple, offset, resultType = _} = | |
| 652 | case value tuple of | |
| 653 | Tuple vs => Vector.sub (vs, offset) | |
| 654 | | _ => Error.bug "ConstantPropagation.Value.select: non-tuple" | |
| 655 | ||
| 656 | fun unit () = tuple (Vector.new0 ()) | |
| 657 | end | |
| 658 | ||
| 659 | val traceSendConApp = | |
| 660 | Trace.trace2 | |
| 661 | ("ConstantPropagation.sendConApp", Value.Data.layout, | |
| 662 | fn {con, args, uniq} => | |
| 663 | Layout.record [("con", Con.layout con), | |
| 664 | ("args", Vector.layout Value.layout args), | |
| 665 | ("uniq", Value.Unique.layout uniq)], | |
| 666 | Unit.layout) | |
| 667 | ||
| 668 | val traceSendConAppLoop = | |
| 669 | Trace.trace | |
| 670 | ("ConstantPropagation.sendConAppLoop", | |
| 671 | Value.Data.layout, Unit.layout) | |
| 672 | ||
| 673 | val traceMakeDataUnknown = | |
| 674 | Trace.trace | |
| 675 | ("ConstantPropagation.makeDataUnknown", | |
| 676 | Value.Data.layout, Unit.layout) | |
| 677 | ||
| 678 | (* ------------------------------------------------- *) | |
| 679 | (* simplify *) | |
| 680 | (* ------------------------------------------------- *) | |
| 681 | ||
| 682 | fun transform (program: Program.t): Program.t = | |
| 683 | let | |
| 684 | val program as Program.T {datatypes, globals, functions, main} = | |
| 685 | eliminateDeadBlocks program | |
| 686 | val {varIsMultiDefed, ...} = Multi.multi program | |
| 687 | val once = not o varIsMultiDefed | |
| 688 | val {get = conInfo: Con.t -> {result: Type.t, | |
| 689 | types: Type.t vector, | |
| 690 | values: Value.t vector}, | |
| 691 | set = setConInfo, ...} = | |
| 692 | Property.getSetOnce | |
| 693 | (Con.plist, Property.initRaise ("conInfo", Con.layout)) | |
| 694 | val conValues = #values o conInfo | |
| 695 | val _ = | |
| 696 | Vector.foreach | |
| 697 | (datatypes, fn Datatype.T {tycon, cons} => | |
| 698 | let | |
| 699 | val result = Type.datatypee tycon | |
| 700 | in | |
| 701 | Vector.foreach | |
| 702 | (cons, fn {con, args} => | |
| 703 | setConInfo (con, | |
| 704 | {result = result, | |
| 705 | types = args, | |
| 706 | values = Vector.map (args, Value.fromType)})) | |
| 707 | end) | |
| 708 | local | |
| 709 | open Value | |
| 710 | in | |
| 711 | val traceCoerce = | |
| 712 | Trace.trace ("ConstantPropagation.Value.coerce", | |
| 713 | fn {from, to} => Layout.record [("from", layout from), | |
| 714 | ("to", layout to)], | |
| 715 | Unit.layout) | |
| 716 | fun makeDataUnknown arg: unit = | |
| 717 | traceMakeDataUnknown | |
| 718 | (fn Data {value, coercedTo, filters, ...} => | |
| 719 | let | |
| 720 | fun doit () = | |
| 721 | (value := Unknown | |
| 722 | ; List.foreach (!coercedTo, makeDataUnknown) | |
| 723 | ; coercedTo := [] | |
| 724 | ; (List.foreach | |
| 725 | (!filters, fn {con, args} => | |
| 726 | coerces {froms = conValues con, | |
| 727 | tos = args}))) | |
| 728 | in | |
| 729 | case !value of | |
| 730 | ConApp _ => doit () | |
| 731 | | Undefined => doit () | |
| 732 | | Unknown => () | |
| 733 | end) arg | |
| 734 | and sendConApp arg: unit = | |
| 735 | traceSendConApp | |
| 736 | (fn (d: data, ca as {con, args, uniq}) => | |
| 737 | let | |
| 738 | val v = ConApp ca | |
| 739 | fun loop arg: unit = | |
| 740 | traceSendConAppLoop | |
| 741 | (fn Data {value, coercedTo, filters, ...} => | |
| 742 | case !value of | |
| 743 | Unknown => () | |
| 744 | | Undefined => | |
| 745 | (value := v | |
| 746 | ; List.foreach (!coercedTo, loop) | |
| 747 | ; (List.foreach | |
| 748 | (!filters, fn {con = con', args = args'} => | |
| 749 | if Con.equals (con, con') | |
| 750 | then coerces {froms = args, tos = args'} | |
| 751 | else ()))) | |
| 752 | | ConApp {con = con', uniq = uniq', ...} => | |
| 753 | if Unique.equals (uniq, uniq') | |
| 754 | orelse (Con.equals (con, con') | |
| 755 | andalso Vector.isEmpty args) | |
| 756 | then () | |
| 757 | else makeDataUnknown d) arg | |
| 758 | in loop d | |
| 759 | end) arg | |
| 760 | and coerces {froms: Value.t vector, tos: Value.t vector} = | |
| 761 | Vector.foreach2 (froms, tos, fn (from, to) => | |
| 762 | coerce {from = from, to = to}) | |
| 763 | and coerce arg = | |
| 764 | traceCoerce | |
| 765 | (fn {from, to} => | |
| 766 | if equals (from, to) | |
| 767 | then () | |
| 768 | else | |
| 769 | let | |
| 770 | fun error () = | |
| 771 | Error.bug | |
| 772 | (concat ["ConstantPropagation.Value.coerce: strange: from: ", | |
| 773 | Layout.toString (Value.layout from), | |
| 774 | " to: ", Layout.toString (Value.layout to)]) | |
| 775 | in | |
| 776 | case (value from, value to) of | |
| 777 | (Const from, Const to) => | |
| 778 | Const.coerce {from = from, to = to} | |
| 779 | | (Datatype from, Datatype to) => | |
| 780 | coerceData {from = from, to = to} | |
| 781 | | (Ref {birth, arg}, Ref {birth = b', arg = a'}) => | |
| 782 | (Birth.coerce {from = birth, to = b'} | |
| 783 | ; unify (arg, a')) | |
| 784 | | (Array {birth = b, length = n, elt = x, raw = r}, | |
| 785 | Array {birth = b', length = n', elt = x', raw = r'}) => | |
| 786 | (Birth.coerce {from = b, to = b'} | |
| 787 | ; coerce {from = n, to = n'} | |
| 788 | ; unify (x, x') | |
| 789 | ; (case (!r, !r') of | |
| 790 | (NONE, r') => r := r' | |
| 791 | | (r, NONE) => r' := r | |
| 792 | | (SOME b, SOME b') => | |
| 793 | (if b = b' | |
| 794 | then () | |
| 795 | else error ()))) | |
| 796 | | (Vector {length = n, elt = x}, | |
| 797 | Vector {length = n', elt = x'}) => | |
| 798 | (coerce {from = n, to = n'} | |
| 799 | ; coerce {from = x, to = x'}) | |
| 800 | | (Tuple vs, Tuple vs') => coerces {froms = vs, tos = vs'} | |
| 801 | | (Weak v, Weak v') => unify (v, v') | |
| 802 | | (Const (Const.T {const = ref (Const.Const c), ...}), | |
| 803 | Vector {elt, length}) => | |
| 804 | let | |
| 805 | val {elt = elt', length = length'} = | |
| 806 | Value.constToEltLength (c, "coerce") | |
| 807 | in | |
| 808 | coerce {from = elt', to = elt} | |
| 809 | ; coerce {from = length', to = length} | |
| 810 | end | |
| 811 | | (_, _) => error () | |
| 812 | end) arg | |
| 813 | and unify (T s: t, T s': t): unit = | |
| 814 | if Set.equals (s, s') | |
| 815 | then () | |
| 816 | else | |
| 817 | let | |
| 818 | val {value, ...} = Set.! s | |
| 819 | val {value = value', ...} = Set.! s' | |
| 820 | fun error () = | |
| 821 | Error.bug | |
| 822 | (concat ["ConstantPropagation.Value.unify: strange: value: ", | |
| 823 | Layout.toString (Value.layout (T s)), | |
| 824 | " value': ", Layout.toString (Value.layout (T s'))]) | |
| 825 | in Set.union (s, s') | |
| 826 | ; case (value, value') of | |
| 827 | (Const c, Const c') => Const.unify (c, c') | |
| 828 | | (Datatype d, Datatype d') => unifyData (d, d') | |
| 829 | | (Ref {birth, arg}, Ref {birth = b', arg = a'}) => | |
| 830 | (Birth.unify (birth, b') | |
| 831 | ; unify (arg, a')) | |
| 832 | | (Array {birth = b, length = n, elt = x, raw = r}, | |
| 833 | Array {birth = b', length = n', elt = x', raw = r'}) => | |
| 834 | (Birth.unify (b, b') | |
| 835 | ; unify (n, n') | |
| 836 | ; unify (x, x') | |
| 837 | ; (case (!r, !r') of | |
| 838 | (NONE, r') => r := r' | |
| 839 | | (r, NONE) => r' := r | |
| 840 | | (SOME b, SOME b') => | |
| 841 | (if b = b' | |
| 842 | then () | |
| 843 | else error ()))) | |
| 844 | | (Vector {length = n, elt = x}, | |
| 845 | Vector {length = n', elt = x'}) => | |
| 846 | (unify (n, n') | |
| 847 | ; unify (x, x')) | |
| 848 | | (Tuple vs, Tuple vs') => Vector.foreach2 (vs, vs', unify) | |
| 849 | | (Weak v, Weak v') => unify (v, v') | |
| 850 | | _ => error () | |
| 851 | end | |
| 852 | and unifyData (d, d') = | |
| 853 | (coerceData {from = d, to = d'} | |
| 854 | ; coerceData {from = d', to = d}) | |
| 855 | and coerceData {from = Data {value, coercedTo, ...}, to} = | |
| 856 | case !value of | |
| 857 | ConApp ca => (List.push (coercedTo, to) | |
| 858 | ; sendConApp (to, ca)) | |
| 859 | | Undefined => List.push (coercedTo, to) | |
| 860 | | Unknown => makeDataUnknown to | |
| 861 | fun conApp {con: Con.t, args: t vector}: t = | |
| 862 | let | |
| 863 | val {values = tos, result, ...} = conInfo con | |
| 864 | in | |
| 865 | coerces {froms = args, tos = tos} | |
| 866 | ; new (Datatype | |
| 867 | (Data {value = ref (ConApp {con = con, args = args, | |
| 868 | uniq = Unique.new ()}), | |
| 869 | coercedTo = ref [], | |
| 870 | filters = ref []}), | |
| 871 | result) | |
| 872 | end | |
| 873 | fun makeUnknown (v: t): unit = | |
| 874 | case value v of | |
| 875 | Array {length, elt, ...} => (makeUnknown length | |
| 876 | ; makeUnknown elt) | |
| 877 | | Const c => Const.makeUnknown c | |
| 878 | | Datatype d => makeDataUnknown d | |
| 879 | | Ref {arg, ...} => makeUnknown arg | |
| 880 | | Tuple vs => Vector.foreach (vs, makeUnknown) | |
| 881 | | Vector {length, elt} => (makeUnknown length | |
| 882 | ; makeUnknown elt) | |
| 883 | | Weak v => makeUnknown v | |
| 884 | fun sideEffect (v: t): unit = | |
| 885 | case value v of | |
| 886 | Array {elt, ...} => makeUnknown elt | |
| 887 | | Const _ => () | |
| 888 | | Datatype _ => () | |
| 889 | | Ref {arg, ...} => makeUnknown arg | |
| 890 | | Vector {elt, ...} => makeUnknown elt | |
| 891 | | Tuple vs => Vector.foreach (vs, sideEffect) | |
| 892 | | Weak v => makeUnknown v | |
| 893 | fun primApp {prim, | |
| 894 | targs = _, | |
| 895 | args: Value.t vector, | |
| 896 | resultVar, | |
| 897 | resultType}: t = | |
| 898 | let | |
| 899 | fun bear z = | |
| 900 | case resultVar of | |
| 901 | SOME resultVar => if once resultVar | |
| 902 | andalso | |
| 903 | Type.isSmall resultType | |
| 904 | then Birth.here z | |
| 905 | else Birth.unknown () | |
| 906 | | _ => Error.bug "ConstantPropagation.Value.primApp.bear" | |
| 907 | fun update (a, v) = | |
| 908 | (coerce {from = v, to = dearray a} | |
| 909 | ; unit ()) | |
| 910 | fun arg i = Vector.sub (args, i) | |
| 911 | datatype z = datatype Prim.Name.t | |
| 912 | fun array (raw, length, birth) = | |
| 913 | let | |
| 914 | val a = fromType resultType | |
| 915 | val _ = coerce {from = length, to = arrayLength a} | |
| 916 | val _ = Birth.coerce {from = birth, to = arrayBirth a} | |
| 917 | val _ = arrayRaw a := SOME raw | |
| 918 | in | |
| 919 | a | |
| 920 | end | |
| 921 | fun vector () = | |
| 922 | let | |
| 923 | val v = fromType resultType | |
| 924 | val l = | |
| 925 | (const o S.Const.word o WordX.fromIntInf) | |
| 926 | (IntInf.fromInt (Vector.length args), | |
| 927 | WordSize.seqIndex ()) | |
| 928 | val _ = coerce {from = l, to = vectorLength v} | |
| 929 | val _ = | |
| 930 | Vector.foreach | |
| 931 | (args, fn arg => | |
| 932 | coerce {from = arg, to = devector v}) | |
| 933 | in | |
| 934 | v | |
| 935 | end | |
| 936 | in | |
| 937 | case Prim.name prim of | |
| 938 | Array_alloc {raw} => array (raw, arg 0, bear ()) | |
| 939 | | Array_copyArray => | |
| 940 | update (arg 0, dearray (arg 2)) | |
| 941 | | Array_copyVector => | |
| 942 | update (arg 0, devector (arg 2)) | |
| 943 | | Array_length => arrayLength (arg 0) | |
| 944 | | Array_sub => dearray (arg 0) | |
| 945 | | Array_toArray => arrayFromArray (arg 0) | |
| 946 | | Array_toVector => vectorFromArray (arg 0) | |
| 947 | | Array_update => update (arg 0, arg 2) | |
| 948 | | Ref_assign => | |
| 949 | (coerce {from = arg 1, to = deref (arg 0)}; unit ()) | |
| 950 | | Ref_deref => deref (arg 0) | |
| 951 | | Ref_ref => | |
| 952 | let | |
| 953 | val v = arg 0 | |
| 954 | val r = fromType resultType | |
| 955 | val _ = coerce {from = v, to = deref r} | |
| 956 | val _ = Birth.coerce {from = bear {init = v}, | |
| 957 | to = refBirth r} | |
| 958 | in | |
| 959 | r | |
| 960 | end | |
| 961 | | Vector_length => vectorLength (arg 0) | |
| 962 | | Vector_sub => devector (arg 0) | |
| 963 | | Vector_vector => vector () | |
| 964 | | Weak_get => deweak (arg 0) | |
| 965 | | Weak_new => | |
| 966 | let | |
| 967 | val w = fromType resultType | |
| 968 | val _ = coerce {from = arg 0, to = deweak w} | |
| 969 | in | |
| 970 | w | |
| 971 | end | |
| 972 | | _ => (if Prim.maySideEffect prim | |
| 973 | then Vector.foreach (args, sideEffect) | |
| 974 | else () | |
| 975 | ; unknown resultType) | |
| 976 | end | |
| 977 | fun filter (variant, con, args) = | |
| 978 | case value variant of | |
| 979 | Datatype (Data {value, filters, ...}) => | |
| 980 | let | |
| 981 | fun save () = List.push (filters, {con = con, args = args}) | |
| 982 | in case !value of | |
| 983 | Undefined => save () | |
| 984 | | Unknown => coerces {froms = conValues con, tos = args} | |
| 985 | | ConApp {con = con', args = args', ...} => | |
| 986 | ((* The save () has to happen before the coerces because | |
| 987 | * they may loop back and change the variant, which | |
| 988 | * would need to then change this value. | |
| 989 | *) | |
| 990 | save () | |
| 991 | ; if Con.equals (con, con') | |
| 992 | then coerces {froms = args', tos = args} | |
| 993 | else ()) | |
| 994 | end | |
| 995 | | _ => Error.bug "ConstantPropagation.Value.filter: non-datatype" | |
| 996 | end | |
| 997 | fun filterIgnore _ = () | |
| 998 | val {value, ...} = | |
| 999 | Control.trace (Control.Detail, "fixed point") | |
| 1000 | analyze { | |
| 1001 | coerce = coerce, | |
| 1002 | conApp = conApp, | |
| 1003 | const = Value.const, | |
| 1004 | filter = filter, | |
| 1005 | filterWord = filterIgnore, | |
| 1006 | fromType = Value.fromType, | |
| 1007 | layout = Value.layout, | |
| 1008 | primApp = primApp, | |
| 1009 | program = program, | |
| 1010 | select = Value.select, | |
| 1011 | tuple = Value.tuple, | |
| 1012 | useFromTypeOnBinds = false | |
| 1013 | } | |
| 1014 | val _ = | |
| 1015 | Control.diagnostics | |
| 1016 | (fn display => | |
| 1017 | let open Layout | |
| 1018 | in | |
| 1019 | display (str "\n\nConstructors:") | |
| 1020 | ; (Vector.foreach | |
| 1021 | (datatypes, fn Datatype.T {tycon, cons} => | |
| 1022 | (display (seq [Tycon.layout tycon, str ": "]) | |
| 1023 | ; Vector.foreach | |
| 1024 | (cons, fn {con, ...} => | |
| 1025 | display | |
| 1026 | (seq [Con.layout con, str ": ", | |
| 1027 | Vector.layout Value.layout (conValues con)]))))) | |
| 1028 | ; display (str "\n\nConstants:") | |
| 1029 | ; (Program.foreachVar | |
| 1030 | (program, fn (x, _) => display (seq [Var.layout x, | |
| 1031 | str " ", | |
| 1032 | Value.layout (value x)]))) | |
| 1033 | end) | |
| 1034 | (* Walk through the program | |
| 1035 | * - removing declarations whose rhs is constant | |
| 1036 | * - replacing variables whose value is constant with globals | |
| 1037 | * - building up the global decs | |
| 1038 | *) | |
| 1039 | val {new = newGlobal, all = allGlobals} = Global.make () | |
| 1040 | fun replaceVar x = | |
| 1041 | case Value.global (value x, newGlobal) of | |
| 1042 | NONE => x | |
| 1043 | | SOME (g, _) => g | |
| 1044 | fun doitStatement (Statement.T {var, ty, exp}) = | |
| 1045 | let | |
| 1046 | fun keep () = | |
| 1047 | SOME (Statement.T {var = var, | |
| 1048 | ty = ty, | |
| 1049 | exp = Exp.replaceVar (exp, replaceVar)}) | |
| 1050 | in | |
| 1051 | case var of | |
| 1052 | NONE => keep () | |
| 1053 | | SOME var => | |
| 1054 | (case (Value.global (value var, newGlobal), exp) of | |
| 1055 | (NONE, _) => keep () | |
| 1056 | | (SOME _, PrimApp {prim, ...}) => | |
| 1057 | if Prim.maySideEffect prim | |
| 1058 | then keep () | |
| 1059 | else NONE | |
| 1060 | | _ => NONE) | |
| 1061 | end | |
| 1062 | fun doitTransfer transfer = | |
| 1063 | Transfer.replaceVar (transfer, replaceVar) | |
| 1064 | fun doitBlock (Block.T {label, args, statements, transfer}) = | |
| 1065 | Block.T {label = label, | |
| 1066 | args = args, | |
| 1067 | statements = Vector.keepAllMap (statements, doitStatement), | |
| 1068 | transfer = doitTransfer transfer} | |
| 1069 | fun doitFunction f = | |
| 1070 | let | |
| 1071 | val {args, blocks, mayInline, name, raises, returns, start} = | |
| 1072 | Function.dest f | |
| 1073 | in | |
| 1074 | Function.new {args = args, | |
| 1075 | blocks = Vector.map (blocks, doitBlock), | |
| 1076 | mayInline = mayInline, | |
| 1077 | name = name, | |
| 1078 | raises = raises, | |
| 1079 | returns = returns, | |
| 1080 | start = start} | |
| 1081 | end | |
| 1082 | val functions = List.revMap (functions, doitFunction) | |
| 1083 | val globals = Vector.keepAllMap (globals, doitStatement) | |
| 1084 | val globals = Vector.concat [allGlobals (), globals] | |
| 1085 | val shrink = shrinkFunction {globals = globals} | |
| 1086 | val program = Program.T {datatypes = datatypes, | |
| 1087 | globals = globals, | |
| 1088 | functions = List.revMap (functions, shrink), | |
| 1089 | main = main} | |
| 1090 | val _ = Program.clearTop program | |
| 1091 | in | |
| 1092 | program | |
| 1093 | end | |
| 1094 | ||
| 1095 | end |