[turbofan] Initial version of number type feedback.

src/compiler/operation-typer.cc

+// 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(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 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::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()));
+
+  lhs = Rangify(lhs);
+  rhs = Rangify(rhs);
+  if (lhs->Is(Type::NaN()) || rhs->Is(Type::NaN())) return Type::NaN();
+  if (lhs->IsRange() && rhs->IsRange()) {
+    return AddRanger(lhs->AsRange(), rhs->AsRange());
+  }
+  // TODO(neis): Deal with numeric bitsets here and elsewhere.
+  return Type::Number();
+}
+
+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::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