| // Copyright 2016 the V8 project authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #include "src/compiler/operation-typer.h" |
| |
| #include "src/factory.h" |
| #include "src/isolate.h" |
| #include "src/type-cache.h" |
| #include "src/types.h" |
| |
| #include "src/objects-inl.h" |
| |
| namespace v8 { |
| namespace internal { |
| namespace compiler { |
| |
| OperationTyper::OperationTyper(Isolate* isolate, Zone* zone) |
| : zone_(zone), cache_(TypeCache::Get()) { |
| Factory* factory = isolate->factory(); |
| singleton_false_ = Type::Constant(factory->false_value(), zone); |
| singleton_true_ = Type::Constant(factory->true_value(), zone); |
| singleton_the_hole_ = Type::Constant(factory->the_hole_value(), zone); |
| } |
| |
| Type* OperationTyper::Merge(Type* left, Type* right) { |
| return Type::Union(left, right, zone()); |
| } |
| |
| Type* OperationTyper::WeakenRange(Type* previous_range, Type* current_range) { |
| static const double kWeakenMinLimits[] = {0.0, |
| -1073741824.0, |
| -2147483648.0, |
| -4294967296.0, |
| -8589934592.0, |
| -17179869184.0, |
| -34359738368.0, |
| -68719476736.0, |
| -137438953472.0, |
| -274877906944.0, |
| -549755813888.0, |
| -1099511627776.0, |
| -2199023255552.0, |
| -4398046511104.0, |
| -8796093022208.0, |
| -17592186044416.0, |
| -35184372088832.0, |
| -70368744177664.0, |
| -140737488355328.0, |
| -281474976710656.0, |
| -562949953421312.0}; |
| static const double kWeakenMaxLimits[] = {0.0, |
| 1073741823.0, |
| 2147483647.0, |
| 4294967295.0, |
| 8589934591.0, |
| 17179869183.0, |
| 34359738367.0, |
| 68719476735.0, |
| 137438953471.0, |
| 274877906943.0, |
| 549755813887.0, |
| 1099511627775.0, |
| 2199023255551.0, |
| 4398046511103.0, |
| 8796093022207.0, |
| 17592186044415.0, |
| 35184372088831.0, |
| 70368744177663.0, |
| 140737488355327.0, |
| 281474976710655.0, |
| 562949953421311.0}; |
| STATIC_ASSERT(arraysize(kWeakenMinLimits) == arraysize(kWeakenMaxLimits)); |
| |
| double current_min = current_range->Min(); |
| double new_min = current_min; |
| // Find the closest lower entry in the list of allowed |
| // minima (or negative infinity if there is no such entry). |
| if (current_min != previous_range->Min()) { |
| new_min = -V8_INFINITY; |
| for (double const min : kWeakenMinLimits) { |
| if (min <= current_min) { |
| new_min = min; |
| break; |
| } |
| } |
| } |
| |
| double current_max = current_range->Max(); |
| double new_max = current_max; |
| // Find the closest greater entry in the list of allowed |
| // maxima (or infinity if there is no such entry). |
| if (current_max != previous_range->Max()) { |
| new_max = V8_INFINITY; |
| for (double const max : kWeakenMaxLimits) { |
| if (max >= current_max) { |
| new_max = max; |
| break; |
| } |
| } |
| } |
| |
| return Type::Range(new_min, new_max, zone()); |
| } |
| |
| Type* OperationTyper::Rangify(Type* type) { |
| if (type->IsRange()) return type; // Shortcut. |
| if (!type->Is(cache_.kInteger)) { |
| return type; // Give up on non-integer types. |
| } |
| double min = type->Min(); |
| double max = type->Max(); |
| // Handle the degenerate case of empty bitset types (such as |
| // OtherUnsigned31 and OtherSigned32 on 64-bit architectures). |
| if (std::isnan(min)) { |
| DCHECK(std::isnan(max)); |
| return type; |
| } |
| return Type::Range(min, max, zone()); |
| } |
| |
| namespace { |
| |
| // Returns the array's least element, ignoring NaN. |
| // There must be at least one non-NaN element. |
| // Any -0 is converted to 0. |
| double array_min(double a[], size_t n) { |
| DCHECK(n != 0); |
| double x = +V8_INFINITY; |
| for (size_t i = 0; i < n; ++i) { |
| if (!std::isnan(a[i])) { |
| x = std::min(a[i], x); |
| } |
| } |
| DCHECK(!std::isnan(x)); |
| return x == 0 ? 0 : x; // -0 -> 0 |
| } |
| |
| // Returns the array's greatest element, ignoring NaN. |
| // There must be at least one non-NaN element. |
| // Any -0 is converted to 0. |
| double array_max(double a[], size_t n) { |
| DCHECK(n != 0); |
| double x = -V8_INFINITY; |
| for (size_t i = 0; i < n; ++i) { |
| if (!std::isnan(a[i])) { |
| x = std::max(a[i], x); |
| } |
| } |
| DCHECK(!std::isnan(x)); |
| return x == 0 ? 0 : x; // -0 -> 0 |
| } |
| |
| } // namespace |
| |
| Type* OperationTyper::AddRanger(double lhs_min, double lhs_max, double rhs_min, |
| double rhs_max) { |
| double results[4]; |
| results[0] = lhs_min + rhs_min; |
| results[1] = lhs_min + rhs_max; |
| results[2] = lhs_max + rhs_min; |
| results[3] = lhs_max + rhs_max; |
| // Since none of the inputs can be -0, the result cannot be -0 either. |
| // However, it can be nan (the sum of two infinities of opposite sign). |
| // On the other hand, if none of the "results" above is nan, then the actual |
| // result cannot be nan either. |
| int nans = 0; |
| for (int i = 0; i < 4; ++i) { |
| if (std::isnan(results[i])) ++nans; |
| } |
| if (nans == 4) return Type::NaN(); // [-inf..-inf] + [inf..inf] or vice versa |
| Type* range = |
| Type::Range(array_min(results, 4), array_max(results, 4), zone()); |
| return nans == 0 ? range : Type::Union(range, Type::NaN(), zone()); |
| // Examples: |
| // [-inf, -inf] + [+inf, +inf] = NaN |
| // [-inf, -inf] + [n, +inf] = [-inf, -inf] \/ NaN |
| // [-inf, +inf] + [n, +inf] = [-inf, +inf] \/ NaN |
| // [-inf, m] + [n, +inf] = [-inf, +inf] \/ NaN |
| } |
| |
| Type* OperationTyper::SubtractRanger(RangeType* lhs, RangeType* rhs) { |
| double results[4]; |
| results[0] = lhs->Min() - rhs->Min(); |
| results[1] = lhs->Min() - rhs->Max(); |
| results[2] = lhs->Max() - rhs->Min(); |
| results[3] = lhs->Max() - rhs->Max(); |
| // Since none of the inputs can be -0, the result cannot be -0. |
| // However, it can be nan (the subtraction of two infinities of same sign). |
| // On the other hand, if none of the "results" above is nan, then the actual |
| // result cannot be nan either. |
| int nans = 0; |
| for (int i = 0; i < 4; ++i) { |
| if (std::isnan(results[i])) ++nans; |
| } |
| if (nans == 4) return Type::NaN(); // [inf..inf] - [inf..inf] (all same sign) |
| Type* range = |
| Type::Range(array_min(results, 4), array_max(results, 4), zone()); |
| return nans == 0 ? range : Type::Union(range, Type::NaN(), zone()); |
| // Examples: |
| // [-inf, +inf] - [-inf, +inf] = [-inf, +inf] \/ NaN |
| // [-inf, -inf] - [-inf, -inf] = NaN |
| // [-inf, -inf] - [n, +inf] = [-inf, -inf] \/ NaN |
| // [m, +inf] - [-inf, n] = [-inf, +inf] \/ NaN |
| } |
| |
| Type* OperationTyper::ModulusRanger(RangeType* lhs, RangeType* rhs) { |
| double lmin = lhs->Min(); |
| double lmax = lhs->Max(); |
| double rmin = rhs->Min(); |
| double rmax = rhs->Max(); |
| |
| double labs = std::max(std::abs(lmin), std::abs(lmax)); |
| double rabs = std::max(std::abs(rmin), std::abs(rmax)) - 1; |
| double abs = std::min(labs, rabs); |
| bool maybe_minus_zero = false; |
| double omin = 0; |
| double omax = 0; |
| if (lmin >= 0) { // {lhs} positive. |
| omin = 0; |
| omax = abs; |
| } else if (lmax <= 0) { // {lhs} negative. |
| omin = 0 - abs; |
| omax = 0; |
| maybe_minus_zero = true; |
| } else { |
| omin = 0 - abs; |
| omax = abs; |
| maybe_minus_zero = true; |
| } |
| |
| Type* result = Type::Range(omin, omax, zone()); |
| if (maybe_minus_zero) result = Type::Union(result, Type::MinusZero(), zone()); |
| return result; |
| } |
| |
| Type* OperationTyper::MultiplyRanger(Type* lhs, Type* rhs) { |
| double results[4]; |
| double lmin = lhs->AsRange()->Min(); |
| double lmax = lhs->AsRange()->Max(); |
| double rmin = rhs->AsRange()->Min(); |
| double rmax = rhs->AsRange()->Max(); |
| results[0] = lmin * rmin; |
| results[1] = lmin * rmax; |
| results[2] = lmax * rmin; |
| results[3] = lmax * rmax; |
| // If the result may be nan, we give up on calculating a precise type, |
| // because |
| // the discontinuity makes it too complicated. Note that even if none of |
| // the |
| // "results" above is nan, the actual result may still be, so we have to do |
| // a |
| // different check: |
| bool maybe_nan = (lhs->Maybe(cache_.kSingletonZero) && |
| (rmin == -V8_INFINITY || rmax == +V8_INFINITY)) || |
| (rhs->Maybe(cache_.kSingletonZero) && |
| (lmin == -V8_INFINITY || lmax == +V8_INFINITY)); |
| if (maybe_nan) return cache_.kIntegerOrMinusZeroOrNaN; // Giving up. |
| bool maybe_minuszero = (lhs->Maybe(cache_.kSingletonZero) && rmin < 0) || |
| (rhs->Maybe(cache_.kSingletonZero) && lmin < 0); |
| Type* range = |
| Type::Range(array_min(results, 4), array_max(results, 4), zone()); |
| return maybe_minuszero ? Type::Union(range, Type::MinusZero(), zone()) |
| : range; |
| } |
| |
| Type* OperationTyper::ToNumber(Type* type) { |
| if (type->Is(Type::Number())) return type; |
| if (type->Is(Type::NullOrUndefined())) { |
| if (type->Is(Type::Null())) return cache_.kSingletonZero; |
| if (type->Is(Type::Undefined())) return Type::NaN(); |
| return Type::Union(Type::NaN(), cache_.kSingletonZero, zone()); |
| } |
| if (type->Is(Type::NumberOrUndefined())) { |
| return Type::Union(Type::Intersect(type, Type::Number(), zone()), |
| Type::NaN(), zone()); |
| } |
| if (type->Is(singleton_false_)) return cache_.kSingletonZero; |
| if (type->Is(singleton_true_)) return cache_.kSingletonOne; |
| if (type->Is(Type::Boolean())) return cache_.kZeroOrOne; |
| if (type->Is(Type::BooleanOrNumber())) { |
| return Type::Union(Type::Intersect(type, Type::Number(), zone()), |
| cache_.kZeroOrOne, zone()); |
| } |
| return Type::Number(); |
| } |
| |
| Type* OperationTyper::NumericAdd(Type* lhs, Type* rhs) { |
| DCHECK(lhs->Is(Type::Number())); |
| DCHECK(rhs->Is(Type::Number())); |
| |
| // We can give more precise types for integers. |
| if (!lhs->Is(cache_.kIntegerOrMinusZeroOrNaN) || |
| !rhs->Is(cache_.kIntegerOrMinusZeroOrNaN)) { |
| return Type::Number(); |
| } |
| Type* int_lhs = Type::Intersect(lhs, cache_.kInteger, zone()); |
| Type* int_rhs = Type::Intersect(rhs, cache_.kInteger, zone()); |
| Type* result = |
| AddRanger(int_lhs->Min(), int_lhs->Max(), int_rhs->Min(), int_rhs->Max()); |
| if (lhs->Maybe(Type::NaN()) || rhs->Maybe(Type::NaN())) { |
| result = Type::Union(result, Type::NaN(), zone()); |
| } |
| if (lhs->Maybe(Type::MinusZero()) && rhs->Maybe(Type::MinusZero())) { |
| result = Type::Union(result, Type::MinusZero(), zone()); |
| } |
| return result; |
| } |
| |
| Type* OperationTyper::NumericSubtract(Type* lhs, Type* rhs) { |
| DCHECK(lhs->Is(Type::Number())); |
| DCHECK(rhs->Is(Type::Number())); |
| |
| lhs = Rangify(lhs); |
| rhs = Rangify(rhs); |
| if (lhs->Is(Type::NaN()) || rhs->Is(Type::NaN())) return Type::NaN(); |
| if (lhs->IsRange() && rhs->IsRange()) { |
| return SubtractRanger(lhs->AsRange(), rhs->AsRange()); |
| } |
| // TODO(neis): Deal with numeric bitsets here and elsewhere. |
| return Type::Number(); |
| } |
| |
| Type* OperationTyper::NumericMultiply(Type* lhs, Type* rhs) { |
| DCHECK(lhs->Is(Type::Number())); |
| DCHECK(rhs->Is(Type::Number())); |
| lhs = Rangify(lhs); |
| rhs = Rangify(rhs); |
| if (lhs->Is(Type::NaN()) || rhs->Is(Type::NaN())) return Type::NaN(); |
| if (lhs->IsRange() && rhs->IsRange()) { |
| return MultiplyRanger(lhs, rhs); |
| } |
| return Type::Number(); |
| } |
| |
| Type* OperationTyper::NumericDivide(Type* lhs, Type* rhs) { |
| DCHECK(lhs->Is(Type::Number())); |
| DCHECK(rhs->Is(Type::Number())); |
| |
| if (lhs->Is(Type::NaN()) || rhs->Is(Type::NaN())) return Type::NaN(); |
| // Division is tricky, so all we do is try ruling out nan. |
| bool maybe_nan = |
| lhs->Maybe(Type::NaN()) || rhs->Maybe(cache_.kZeroish) || |
| ((lhs->Min() == -V8_INFINITY || lhs->Max() == +V8_INFINITY) && |
| (rhs->Min() == -V8_INFINITY || rhs->Max() == +V8_INFINITY)); |
| return maybe_nan ? Type::Number() : Type::OrderedNumber(); |
| } |
| |
| Type* OperationTyper::NumericModulus(Type* lhs, Type* rhs) { |
| DCHECK(lhs->Is(Type::Number())); |
| DCHECK(rhs->Is(Type::Number())); |
| if (lhs->Is(Type::NaN()) || rhs->Is(Type::NaN())) return Type::NaN(); |
| |
| if (lhs->Maybe(Type::NaN()) || rhs->Maybe(cache_.kZeroish) || |
| lhs->Min() == -V8_INFINITY || lhs->Max() == +V8_INFINITY) { |
| // Result maybe NaN. |
| return Type::Number(); |
| } |
| |
| lhs = Rangify(lhs); |
| rhs = Rangify(rhs); |
| if (lhs->IsRange() && rhs->IsRange()) { |
| return ModulusRanger(lhs->AsRange(), rhs->AsRange()); |
| } |
| return Type::OrderedNumber(); |
| } |
| |
| Type* OperationTyper::ToPrimitive(Type* type) { |
| if (type->Is(Type::Primitive()) && !type->Maybe(Type::Receiver())) { |
| return type; |
| } |
| return Type::Primitive(); |
| } |
| |
| Type* OperationTyper::Invert(Type* type) { |
| DCHECK(type->Is(Type::Boolean())); |
| DCHECK(type->IsInhabited()); |
| if (type->Is(singleton_false())) return singleton_true(); |
| if (type->Is(singleton_true())) return singleton_false(); |
| return type; |
| } |
| |
| OperationTyper::ComparisonOutcome OperationTyper::Invert( |
| ComparisonOutcome outcome) { |
| ComparisonOutcome result(0); |
| if ((outcome & kComparisonUndefined) != 0) result |= kComparisonUndefined; |
| if ((outcome & kComparisonTrue) != 0) result |= kComparisonFalse; |
| if ((outcome & kComparisonFalse) != 0) result |= kComparisonTrue; |
| return result; |
| } |
| |
| Type* OperationTyper::FalsifyUndefined(ComparisonOutcome outcome) { |
| if ((outcome & kComparisonFalse) != 0 || |
| (outcome & kComparisonUndefined) != 0) { |
| return (outcome & kComparisonTrue) != 0 ? Type::Boolean() |
| : singleton_false(); |
| } |
| // Type should be non empty, so we know it should be true. |
| DCHECK((outcome & kComparisonTrue) != 0); |
| return singleton_true(); |
| } |
| |
| Type* OperationTyper::TypeJSAdd(Type* lhs, Type* rhs) { |
| lhs = ToPrimitive(lhs); |
| rhs = ToPrimitive(rhs); |
| if (lhs->Maybe(Type::String()) || rhs->Maybe(Type::String())) { |
| if (lhs->Is(Type::String()) || rhs->Is(Type::String())) { |
| return Type::String(); |
| } else { |
| return Type::NumberOrString(); |
| } |
| } |
| lhs = ToNumber(lhs); |
| rhs = ToNumber(rhs); |
| return NumericAdd(lhs, rhs); |
| } |
| |
| Type* OperationTyper::TypeJSSubtract(Type* lhs, Type* rhs) { |
| return NumericSubtract(ToNumber(lhs), ToNumber(rhs)); |
| } |
| |
| } // namespace compiler |
| } // namespace internal |
| } // namespace v8 |