Ben Murdoch | 61f157c | 2016-09-16 13:49:30 +0100 | [diff] [blame^] | 1 | // Copyright 2016 the V8 project authors. All rights reserved. |
| 2 | // Use of this source code is governed by a BSD-style license that can be |
| 3 | // found in the LICENSE file. |
| 4 | |
| 5 | #include "src/compiler/operation-typer.h" |
| 6 | |
| 7 | #include "src/factory.h" |
| 8 | #include "src/isolate.h" |
| 9 | #include "src/type-cache.h" |
| 10 | #include "src/types.h" |
| 11 | |
| 12 | #include "src/objects-inl.h" |
| 13 | |
| 14 | namespace v8 { |
| 15 | namespace internal { |
| 16 | namespace compiler { |
| 17 | |
| 18 | OperationTyper::OperationTyper(Isolate* isolate, Zone* zone) |
| 19 | : zone_(zone), cache_(TypeCache::Get()) { |
| 20 | Factory* factory = isolate->factory(); |
| 21 | singleton_false_ = Type::Constant(factory->false_value(), zone); |
| 22 | singleton_true_ = Type::Constant(factory->true_value(), zone); |
| 23 | singleton_the_hole_ = Type::Constant(factory->the_hole_value(), zone); |
| 24 | } |
| 25 | |
| 26 | Type* OperationTyper::Merge(Type* left, Type* right) { |
| 27 | return Type::Union(left, right, zone()); |
| 28 | } |
| 29 | |
| 30 | Type* OperationTyper::WeakenRange(Type* previous_range, Type* current_range) { |
| 31 | static const double kWeakenMinLimits[] = {0.0, |
| 32 | -1073741824.0, |
| 33 | -2147483648.0, |
| 34 | -4294967296.0, |
| 35 | -8589934592.0, |
| 36 | -17179869184.0, |
| 37 | -34359738368.0, |
| 38 | -68719476736.0, |
| 39 | -137438953472.0, |
| 40 | -274877906944.0, |
| 41 | -549755813888.0, |
| 42 | -1099511627776.0, |
| 43 | -2199023255552.0, |
| 44 | -4398046511104.0, |
| 45 | -8796093022208.0, |
| 46 | -17592186044416.0, |
| 47 | -35184372088832.0, |
| 48 | -70368744177664.0, |
| 49 | -140737488355328.0, |
| 50 | -281474976710656.0, |
| 51 | -562949953421312.0}; |
| 52 | static const double kWeakenMaxLimits[] = {0.0, |
| 53 | 1073741823.0, |
| 54 | 2147483647.0, |
| 55 | 4294967295.0, |
| 56 | 8589934591.0, |
| 57 | 17179869183.0, |
| 58 | 34359738367.0, |
| 59 | 68719476735.0, |
| 60 | 137438953471.0, |
| 61 | 274877906943.0, |
| 62 | 549755813887.0, |
| 63 | 1099511627775.0, |
| 64 | 2199023255551.0, |
| 65 | 4398046511103.0, |
| 66 | 8796093022207.0, |
| 67 | 17592186044415.0, |
| 68 | 35184372088831.0, |
| 69 | 70368744177663.0, |
| 70 | 140737488355327.0, |
| 71 | 281474976710655.0, |
| 72 | 562949953421311.0}; |
| 73 | STATIC_ASSERT(arraysize(kWeakenMinLimits) == arraysize(kWeakenMaxLimits)); |
| 74 | |
| 75 | double current_min = current_range->Min(); |
| 76 | double new_min = current_min; |
| 77 | // Find the closest lower entry in the list of allowed |
| 78 | // minima (or negative infinity if there is no such entry). |
| 79 | if (current_min != previous_range->Min()) { |
| 80 | new_min = -V8_INFINITY; |
| 81 | for (double const min : kWeakenMinLimits) { |
| 82 | if (min <= current_min) { |
| 83 | new_min = min; |
| 84 | break; |
| 85 | } |
| 86 | } |
| 87 | } |
| 88 | |
| 89 | double current_max = current_range->Max(); |
| 90 | double new_max = current_max; |
| 91 | // Find the closest greater entry in the list of allowed |
| 92 | // maxima (or infinity if there is no such entry). |
| 93 | if (current_max != previous_range->Max()) { |
| 94 | new_max = V8_INFINITY; |
| 95 | for (double const max : kWeakenMaxLimits) { |
| 96 | if (max >= current_max) { |
| 97 | new_max = max; |
| 98 | break; |
| 99 | } |
| 100 | } |
| 101 | } |
| 102 | |
| 103 | return Type::Range(new_min, new_max, zone()); |
| 104 | } |
| 105 | |
| 106 | Type* OperationTyper::Rangify(Type* type) { |
| 107 | if (type->IsRange()) return type; // Shortcut. |
| 108 | if (!type->Is(cache_.kInteger)) { |
| 109 | return type; // Give up on non-integer types. |
| 110 | } |
| 111 | double min = type->Min(); |
| 112 | double max = type->Max(); |
| 113 | // Handle the degenerate case of empty bitset types (such as |
| 114 | // OtherUnsigned31 and OtherSigned32 on 64-bit architectures). |
| 115 | if (std::isnan(min)) { |
| 116 | DCHECK(std::isnan(max)); |
| 117 | return type; |
| 118 | } |
| 119 | return Type::Range(min, max, zone()); |
| 120 | } |
| 121 | |
| 122 | namespace { |
| 123 | |
| 124 | // Returns the array's least element, ignoring NaN. |
| 125 | // There must be at least one non-NaN element. |
| 126 | // Any -0 is converted to 0. |
| 127 | double array_min(double a[], size_t n) { |
| 128 | DCHECK(n != 0); |
| 129 | double x = +V8_INFINITY; |
| 130 | for (size_t i = 0; i < n; ++i) { |
| 131 | if (!std::isnan(a[i])) { |
| 132 | x = std::min(a[i], x); |
| 133 | } |
| 134 | } |
| 135 | DCHECK(!std::isnan(x)); |
| 136 | return x == 0 ? 0 : x; // -0 -> 0 |
| 137 | } |
| 138 | |
| 139 | // Returns the array's greatest element, ignoring NaN. |
| 140 | // There must be at least one non-NaN element. |
| 141 | // Any -0 is converted to 0. |
| 142 | double array_max(double a[], size_t n) { |
| 143 | DCHECK(n != 0); |
| 144 | double x = -V8_INFINITY; |
| 145 | for (size_t i = 0; i < n; ++i) { |
| 146 | if (!std::isnan(a[i])) { |
| 147 | x = std::max(a[i], x); |
| 148 | } |
| 149 | } |
| 150 | DCHECK(!std::isnan(x)); |
| 151 | return x == 0 ? 0 : x; // -0 -> 0 |
| 152 | } |
| 153 | |
| 154 | } // namespace |
| 155 | |
| 156 | Type* OperationTyper::AddRanger(double lhs_min, double lhs_max, double rhs_min, |
| 157 | double rhs_max) { |
| 158 | double results[4]; |
| 159 | results[0] = lhs_min + rhs_min; |
| 160 | results[1] = lhs_min + rhs_max; |
| 161 | results[2] = lhs_max + rhs_min; |
| 162 | results[3] = lhs_max + rhs_max; |
| 163 | // Since none of the inputs can be -0, the result cannot be -0 either. |
| 164 | // However, it can be nan (the sum of two infinities of opposite sign). |
| 165 | // On the other hand, if none of the "results" above is nan, then the actual |
| 166 | // result cannot be nan either. |
| 167 | int nans = 0; |
| 168 | for (int i = 0; i < 4; ++i) { |
| 169 | if (std::isnan(results[i])) ++nans; |
| 170 | } |
| 171 | if (nans == 4) return Type::NaN(); // [-inf..-inf] + [inf..inf] or vice versa |
| 172 | Type* range = |
| 173 | Type::Range(array_min(results, 4), array_max(results, 4), zone()); |
| 174 | return nans == 0 ? range : Type::Union(range, Type::NaN(), zone()); |
| 175 | // Examples: |
| 176 | // [-inf, -inf] + [+inf, +inf] = NaN |
| 177 | // [-inf, -inf] + [n, +inf] = [-inf, -inf] \/ NaN |
| 178 | // [-inf, +inf] + [n, +inf] = [-inf, +inf] \/ NaN |
| 179 | // [-inf, m] + [n, +inf] = [-inf, +inf] \/ NaN |
| 180 | } |
| 181 | |
| 182 | Type* OperationTyper::SubtractRanger(RangeType* lhs, RangeType* rhs) { |
| 183 | double results[4]; |
| 184 | results[0] = lhs->Min() - rhs->Min(); |
| 185 | results[1] = lhs->Min() - rhs->Max(); |
| 186 | results[2] = lhs->Max() - rhs->Min(); |
| 187 | results[3] = lhs->Max() - rhs->Max(); |
| 188 | // Since none of the inputs can be -0, the result cannot be -0. |
| 189 | // However, it can be nan (the subtraction of two infinities of same sign). |
| 190 | // On the other hand, if none of the "results" above is nan, then the actual |
| 191 | // result cannot be nan either. |
| 192 | int nans = 0; |
| 193 | for (int i = 0; i < 4; ++i) { |
| 194 | if (std::isnan(results[i])) ++nans; |
| 195 | } |
| 196 | if (nans == 4) return Type::NaN(); // [inf..inf] - [inf..inf] (all same sign) |
| 197 | Type* range = |
| 198 | Type::Range(array_min(results, 4), array_max(results, 4), zone()); |
| 199 | return nans == 0 ? range : Type::Union(range, Type::NaN(), zone()); |
| 200 | // Examples: |
| 201 | // [-inf, +inf] - [-inf, +inf] = [-inf, +inf] \/ NaN |
| 202 | // [-inf, -inf] - [-inf, -inf] = NaN |
| 203 | // [-inf, -inf] - [n, +inf] = [-inf, -inf] \/ NaN |
| 204 | // [m, +inf] - [-inf, n] = [-inf, +inf] \/ NaN |
| 205 | } |
| 206 | |
| 207 | Type* OperationTyper::ModulusRanger(RangeType* lhs, RangeType* rhs) { |
| 208 | double lmin = lhs->Min(); |
| 209 | double lmax = lhs->Max(); |
| 210 | double rmin = rhs->Min(); |
| 211 | double rmax = rhs->Max(); |
| 212 | |
| 213 | double labs = std::max(std::abs(lmin), std::abs(lmax)); |
| 214 | double rabs = std::max(std::abs(rmin), std::abs(rmax)) - 1; |
| 215 | double abs = std::min(labs, rabs); |
| 216 | bool maybe_minus_zero = false; |
| 217 | double omin = 0; |
| 218 | double omax = 0; |
| 219 | if (lmin >= 0) { // {lhs} positive. |
| 220 | omin = 0; |
| 221 | omax = abs; |
| 222 | } else if (lmax <= 0) { // {lhs} negative. |
| 223 | omin = 0 - abs; |
| 224 | omax = 0; |
| 225 | maybe_minus_zero = true; |
| 226 | } else { |
| 227 | omin = 0 - abs; |
| 228 | omax = abs; |
| 229 | maybe_minus_zero = true; |
| 230 | } |
| 231 | |
| 232 | Type* result = Type::Range(omin, omax, zone()); |
| 233 | if (maybe_minus_zero) result = Type::Union(result, Type::MinusZero(), zone()); |
| 234 | return result; |
| 235 | } |
| 236 | |
| 237 | Type* OperationTyper::MultiplyRanger(Type* lhs, Type* rhs) { |
| 238 | double results[4]; |
| 239 | double lmin = lhs->AsRange()->Min(); |
| 240 | double lmax = lhs->AsRange()->Max(); |
| 241 | double rmin = rhs->AsRange()->Min(); |
| 242 | double rmax = rhs->AsRange()->Max(); |
| 243 | results[0] = lmin * rmin; |
| 244 | results[1] = lmin * rmax; |
| 245 | results[2] = lmax * rmin; |
| 246 | results[3] = lmax * rmax; |
| 247 | // If the result may be nan, we give up on calculating a precise type, |
| 248 | // because |
| 249 | // the discontinuity makes it too complicated. Note that even if none of |
| 250 | // the |
| 251 | // "results" above is nan, the actual result may still be, so we have to do |
| 252 | // a |
| 253 | // different check: |
| 254 | bool maybe_nan = (lhs->Maybe(cache_.kSingletonZero) && |
| 255 | (rmin == -V8_INFINITY || rmax == +V8_INFINITY)) || |
| 256 | (rhs->Maybe(cache_.kSingletonZero) && |
| 257 | (lmin == -V8_INFINITY || lmax == +V8_INFINITY)); |
| 258 | if (maybe_nan) return cache_.kIntegerOrMinusZeroOrNaN; // Giving up. |
| 259 | bool maybe_minuszero = (lhs->Maybe(cache_.kSingletonZero) && rmin < 0) || |
| 260 | (rhs->Maybe(cache_.kSingletonZero) && lmin < 0); |
| 261 | Type* range = |
| 262 | Type::Range(array_min(results, 4), array_max(results, 4), zone()); |
| 263 | return maybe_minuszero ? Type::Union(range, Type::MinusZero(), zone()) |
| 264 | : range; |
| 265 | } |
| 266 | |
| 267 | Type* OperationTyper::ToNumber(Type* type) { |
| 268 | if (type->Is(Type::Number())) return type; |
| 269 | if (type->Is(Type::NullOrUndefined())) { |
| 270 | if (type->Is(Type::Null())) return cache_.kSingletonZero; |
| 271 | if (type->Is(Type::Undefined())) return Type::NaN(); |
| 272 | return Type::Union(Type::NaN(), cache_.kSingletonZero, zone()); |
| 273 | } |
| 274 | if (type->Is(Type::NumberOrUndefined())) { |
| 275 | return Type::Union(Type::Intersect(type, Type::Number(), zone()), |
| 276 | Type::NaN(), zone()); |
| 277 | } |
| 278 | if (type->Is(singleton_false_)) return cache_.kSingletonZero; |
| 279 | if (type->Is(singleton_true_)) return cache_.kSingletonOne; |
| 280 | if (type->Is(Type::Boolean())) return cache_.kZeroOrOne; |
| 281 | if (type->Is(Type::BooleanOrNumber())) { |
| 282 | return Type::Union(Type::Intersect(type, Type::Number(), zone()), |
| 283 | cache_.kZeroOrOne, zone()); |
| 284 | } |
| 285 | return Type::Number(); |
| 286 | } |
| 287 | |
| 288 | Type* OperationTyper::NumericAdd(Type* lhs, Type* rhs) { |
| 289 | DCHECK(lhs->Is(Type::Number())); |
| 290 | DCHECK(rhs->Is(Type::Number())); |
| 291 | |
| 292 | // We can give more precise types for integers. |
| 293 | if (!lhs->Is(cache_.kIntegerOrMinusZeroOrNaN) || |
| 294 | !rhs->Is(cache_.kIntegerOrMinusZeroOrNaN)) { |
| 295 | return Type::Number(); |
| 296 | } |
| 297 | Type* int_lhs = Type::Intersect(lhs, cache_.kInteger, zone()); |
| 298 | Type* int_rhs = Type::Intersect(rhs, cache_.kInteger, zone()); |
| 299 | Type* result = |
| 300 | AddRanger(int_lhs->Min(), int_lhs->Max(), int_rhs->Min(), int_rhs->Max()); |
| 301 | if (lhs->Maybe(Type::NaN()) || rhs->Maybe(Type::NaN())) { |
| 302 | result = Type::Union(result, Type::NaN(), zone()); |
| 303 | } |
| 304 | if (lhs->Maybe(Type::MinusZero()) && rhs->Maybe(Type::MinusZero())) { |
| 305 | result = Type::Union(result, Type::MinusZero(), zone()); |
| 306 | } |
| 307 | return result; |
| 308 | } |
| 309 | |
| 310 | Type* OperationTyper::NumericSubtract(Type* lhs, Type* rhs) { |
| 311 | DCHECK(lhs->Is(Type::Number())); |
| 312 | DCHECK(rhs->Is(Type::Number())); |
| 313 | |
| 314 | lhs = Rangify(lhs); |
| 315 | rhs = Rangify(rhs); |
| 316 | if (lhs->Is(Type::NaN()) || rhs->Is(Type::NaN())) return Type::NaN(); |
| 317 | if (lhs->IsRange() && rhs->IsRange()) { |
| 318 | return SubtractRanger(lhs->AsRange(), rhs->AsRange()); |
| 319 | } |
| 320 | // TODO(neis): Deal with numeric bitsets here and elsewhere. |
| 321 | return Type::Number(); |
| 322 | } |
| 323 | |
| 324 | Type* OperationTyper::NumericMultiply(Type* lhs, Type* rhs) { |
| 325 | DCHECK(lhs->Is(Type::Number())); |
| 326 | DCHECK(rhs->Is(Type::Number())); |
| 327 | lhs = Rangify(lhs); |
| 328 | rhs = Rangify(rhs); |
| 329 | if (lhs->Is(Type::NaN()) || rhs->Is(Type::NaN())) return Type::NaN(); |
| 330 | if (lhs->IsRange() && rhs->IsRange()) { |
| 331 | return MultiplyRanger(lhs, rhs); |
| 332 | } |
| 333 | return Type::Number(); |
| 334 | } |
| 335 | |
| 336 | Type* OperationTyper::NumericDivide(Type* lhs, Type* rhs) { |
| 337 | DCHECK(lhs->Is(Type::Number())); |
| 338 | DCHECK(rhs->Is(Type::Number())); |
| 339 | |
| 340 | if (lhs->Is(Type::NaN()) || rhs->Is(Type::NaN())) return Type::NaN(); |
| 341 | // Division is tricky, so all we do is try ruling out nan. |
| 342 | bool maybe_nan = |
| 343 | lhs->Maybe(Type::NaN()) || rhs->Maybe(cache_.kZeroish) || |
| 344 | ((lhs->Min() == -V8_INFINITY || lhs->Max() == +V8_INFINITY) && |
| 345 | (rhs->Min() == -V8_INFINITY || rhs->Max() == +V8_INFINITY)); |
| 346 | return maybe_nan ? Type::Number() : Type::OrderedNumber(); |
| 347 | } |
| 348 | |
| 349 | Type* OperationTyper::NumericModulus(Type* lhs, Type* rhs) { |
| 350 | DCHECK(lhs->Is(Type::Number())); |
| 351 | DCHECK(rhs->Is(Type::Number())); |
| 352 | if (lhs->Is(Type::NaN()) || rhs->Is(Type::NaN())) return Type::NaN(); |
| 353 | |
| 354 | if (lhs->Maybe(Type::NaN()) || rhs->Maybe(cache_.kZeroish) || |
| 355 | lhs->Min() == -V8_INFINITY || lhs->Max() == +V8_INFINITY) { |
| 356 | // Result maybe NaN. |
| 357 | return Type::Number(); |
| 358 | } |
| 359 | |
| 360 | lhs = Rangify(lhs); |
| 361 | rhs = Rangify(rhs); |
| 362 | if (lhs->IsRange() && rhs->IsRange()) { |
| 363 | return ModulusRanger(lhs->AsRange(), rhs->AsRange()); |
| 364 | } |
| 365 | return Type::OrderedNumber(); |
| 366 | } |
| 367 | |
| 368 | Type* OperationTyper::ToPrimitive(Type* type) { |
| 369 | if (type->Is(Type::Primitive()) && !type->Maybe(Type::Receiver())) { |
| 370 | return type; |
| 371 | } |
| 372 | return Type::Primitive(); |
| 373 | } |
| 374 | |
| 375 | Type* OperationTyper::Invert(Type* type) { |
| 376 | DCHECK(type->Is(Type::Boolean())); |
| 377 | DCHECK(type->IsInhabited()); |
| 378 | if (type->Is(singleton_false())) return singleton_true(); |
| 379 | if (type->Is(singleton_true())) return singleton_false(); |
| 380 | return type; |
| 381 | } |
| 382 | |
| 383 | OperationTyper::ComparisonOutcome OperationTyper::Invert( |
| 384 | ComparisonOutcome outcome) { |
| 385 | ComparisonOutcome result(0); |
| 386 | if ((outcome & kComparisonUndefined) != 0) result |= kComparisonUndefined; |
| 387 | if ((outcome & kComparisonTrue) != 0) result |= kComparisonFalse; |
| 388 | if ((outcome & kComparisonFalse) != 0) result |= kComparisonTrue; |
| 389 | return result; |
| 390 | } |
| 391 | |
| 392 | Type* OperationTyper::FalsifyUndefined(ComparisonOutcome outcome) { |
| 393 | if ((outcome & kComparisonFalse) != 0 || |
| 394 | (outcome & kComparisonUndefined) != 0) { |
| 395 | return (outcome & kComparisonTrue) != 0 ? Type::Boolean() |
| 396 | : singleton_false(); |
| 397 | } |
| 398 | // Type should be non empty, so we know it should be true. |
| 399 | DCHECK((outcome & kComparisonTrue) != 0); |
| 400 | return singleton_true(); |
| 401 | } |
| 402 | |
| 403 | Type* OperationTyper::TypeJSAdd(Type* lhs, Type* rhs) { |
| 404 | lhs = ToPrimitive(lhs); |
| 405 | rhs = ToPrimitive(rhs); |
| 406 | if (lhs->Maybe(Type::String()) || rhs->Maybe(Type::String())) { |
| 407 | if (lhs->Is(Type::String()) || rhs->Is(Type::String())) { |
| 408 | return Type::String(); |
| 409 | } else { |
| 410 | return Type::NumberOrString(); |
| 411 | } |
| 412 | } |
| 413 | lhs = ToNumber(lhs); |
| 414 | rhs = ToNumber(rhs); |
| 415 | return NumericAdd(lhs, rhs); |
| 416 | } |
| 417 | |
| 418 | Type* OperationTyper::TypeJSSubtract(Type* lhs, Type* rhs) { |
| 419 | return NumericSubtract(ToNumber(lhs), ToNumber(rhs)); |
| 420 | } |
| 421 | |
| 422 | } // namespace compiler |
| 423 | } // namespace internal |
| 424 | } // namespace v8 |