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+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: set ts=8 sts=2 et sw=2 tw=80:
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef jit_RangeAnalysis_h
+#define jit_RangeAnalysis_h
+
+#include "mozilla/Assertions.h"
+#include "mozilla/Attributes.h"
+#include "mozilla/DebugOnly.h"
+#include "mozilla/FloatingPoint.h"
+#include "mozilla/MathAlgorithms.h"
+
+#include <algorithm>
+#include <stdint.h>
+
+#include "jit/IonAnalysis.h"
+#include "jit/IonTypes.h"
+#include "jit/JitAllocPolicy.h"
+#include "js/AllocPolicy.h"
+#include "js/Value.h"
+#include "js/Vector.h"
+
+namespace js {
+
+class JS_PUBLIC_API GenericPrinter;
+
+namespace jit {
+
+class MBasicBlock;
+class MBinaryBitwiseInstruction;
+class MBoundsCheck;
+class MDefinition;
+class MIRGenerator;
+class MIRGraph;
+class MPhi;
+class MTest;
+
+enum class TruncateKind;
+
+// An upper bound computed on the number of backedges a loop will take.
+// This count only includes backedges taken while running Ion code: for OSR
+// loops, this will exclude iterations that executed in the interpreter or in
+// baseline compiled code.
+struct LoopIterationBound : public TempObject {
+ // Loop for which this bound applies.
+ MBasicBlock* header;
+
+ // Test from which this bound was derived; after executing exactly 'bound'
+ // times this test will exit the loop. Code in the loop body which this
+ // test dominates (will include the backedge) will execute at most 'bound'
+ // times. Other code in the loop will execute at most '1 + Max(bound, 0)'
+ // times.
+ MTest* test;
+
+ // Symbolic bound computed for the number of backedge executions. The terms
+ // in this bound are all loop invariant.
+ LinearSum boundSum;
+
+ // Linear sum for the number of iterations already executed, at the start
+ // of the loop header. This will use loop invariant terms and header phis.
+ LinearSum currentSum;
+
+ LoopIterationBound(MBasicBlock* header, MTest* test,
+ const LinearSum& boundSum, const LinearSum& currentSum)
+ : header(header),
+ test(test),
+ boundSum(boundSum),
+ currentSum(currentSum) {}
+};
+
+typedef Vector<LoopIterationBound*, 0, SystemAllocPolicy>
+ LoopIterationBoundVector;
+
+// A symbolic upper or lower bound computed for a term.
+struct SymbolicBound : public TempObject {
+ private:
+ SymbolicBound(LoopIterationBound* loop, const LinearSum& sum)
+ : loop(loop), sum(sum) {}
+
+ public:
+ // Any loop iteration bound from which this was derived.
+ //
+ // If non-nullptr, then 'sum' is only valid within the loop body, at
+ // points dominated by the loop bound's test (see LoopIterationBound).
+ //
+ // If nullptr, then 'sum' is always valid.
+ LoopIterationBound* loop;
+
+ static SymbolicBound* New(TempAllocator& alloc, LoopIterationBound* loop,
+ const LinearSum& sum) {
+ return new (alloc) SymbolicBound(loop, sum);
+ }
+
+ // Computed symbolic bound, see above.
+ LinearSum sum;
+
+ void dump(GenericPrinter& out) const;
+ void dump() const;
+};
+
+class RangeAnalysis {
+ protected:
+ bool blockDominates(MBasicBlock* b, MBasicBlock* b2);
+ void replaceDominatedUsesWith(MDefinition* orig, MDefinition* dom,
+ MBasicBlock* block);
+
+ protected:
+ MIRGenerator* mir;
+ MIRGraph& graph_;
+ Vector<MBinaryBitwiseInstruction*, 16, SystemAllocPolicy> bitops;
+
+ TempAllocator& alloc() const;
+
+ public:
+ RangeAnalysis(MIRGenerator* mir, MIRGraph& graph) : mir(mir), graph_(graph) {}
+ [[nodiscard]] bool addBetaNodes();
+ [[nodiscard]] bool analyze();
+ [[nodiscard]] bool addRangeAssertions();
+ [[nodiscard]] bool removeBetaNodes();
+ [[nodiscard]] bool prepareForUCE(bool* shouldRemoveDeadCode);
+ [[nodiscard]] bool tryRemovingGuards();
+ [[nodiscard]] bool truncate();
+ [[nodiscard]] bool removeUnnecessaryBitops();
+
+ private:
+ bool canTruncate(MDefinition* def, TruncateKind kind) const;
+ void adjustTruncatedInputs(MDefinition* def);
+
+ // Any iteration bounds discovered for loops in the graph.
+ LoopIterationBoundVector loopIterationBounds;
+
+ private:
+ [[nodiscard]] bool analyzeLoop(MBasicBlock* header);
+ LoopIterationBound* analyzeLoopIterationCount(MBasicBlock* header,
+ MTest* test,
+ BranchDirection direction);
+ void analyzeLoopPhi(LoopIterationBound* loopBound, MPhi* phi);
+ [[nodiscard]] bool tryHoistBoundsCheck(MBasicBlock* header,
+ MBoundsCheck* ins);
+};
+
+class Range : public TempObject {
+ public:
+ // Int32 are signed. INT32_MAX is pow(2,31)-1 and INT32_MIN is -pow(2,31),
+ // so the greatest exponent we need is 31.
+ static const uint16_t MaxInt32Exponent = 31;
+
+ // UInt32 are unsigned. UINT32_MAX is pow(2,32)-1, so it's the greatest
+ // value that has an exponent of 31.
+ static const uint16_t MaxUInt32Exponent = 31;
+
+ // Maximal exponenent under which we have no precission loss on double
+ // operations. Double has 52 bits of mantissa, so 2^52+1 cannot be
+ // represented without loss.
+ static const uint16_t MaxTruncatableExponent =
+ mozilla::FloatingPoint<double>::kExponentShift;
+
+ // Maximum exponent for finite values.
+ static const uint16_t MaxFiniteExponent =
+ mozilla::FloatingPoint<double>::kExponentBias;
+
+ // An special exponent value representing all non-NaN values. This
+ // includes finite values and the infinities.
+ static const uint16_t IncludesInfinity = MaxFiniteExponent + 1;
+
+ // An special exponent value representing all possible double-precision
+ // values. This includes finite values, the infinities, and NaNs.
+ static const uint16_t IncludesInfinityAndNaN = UINT16_MAX;
+
+ // This range class uses int32_t ranges, but has several interfaces which
+ // use int64_t, which either holds an int32_t value, or one of the following
+ // special values which mean a value which is beyond the int32 range,
+ // potentially including infinity or NaN. These special values are
+ // guaranteed to compare greater, and less than, respectively, any int32_t
+ // value.
+ static const int64_t NoInt32UpperBound = int64_t(JSVAL_INT_MAX) + 1;
+ static const int64_t NoInt32LowerBound = int64_t(JSVAL_INT_MIN) - 1;
+
+ enum FractionalPartFlag : bool {
+ ExcludesFractionalParts = false,
+ IncludesFractionalParts = true
+ };
+ enum NegativeZeroFlag : bool {
+ ExcludesNegativeZero = false,
+ IncludesNegativeZero = true
+ };
+
+ private:
+ // Absolute ranges.
+ //
+ // We represent ranges where the endpoints can be in the set:
+ // {-infty} U [INT_MIN, INT_MAX] U {infty}. A bound of +/-
+ // infty means that the value may have overflowed in that
+ // direction. When computing the range of an integer
+ // instruction, the ranges of the operands can be clamped to
+ // [INT_MIN, INT_MAX], since if they had overflowed they would
+ // no longer be integers. This is important for optimizations
+ // and somewhat subtle.
+ //
+ // N.B.: All of the operations that compute new ranges based
+ // on existing ranges will ignore the hasInt32*Bound_ flags of the
+ // input ranges; that is, they implicitly clamp the ranges of
+ // the inputs to [INT_MIN, INT_MAX]. Therefore, while our range might
+ // be unbounded (and could overflow), when using this information to
+ // propagate through other ranges, we disregard this fact; if that code
+ // executes, then the overflow did not occur, so we may safely assume
+ // that the range is [INT_MIN, INT_MAX] instead.
+ //
+ // To facilitate this trick, we maintain the invariants that:
+ // 1) hasInt32LowerBound_ == false implies lower_ == JSVAL_INT_MIN
+ // 2) hasInt32UpperBound_ == false implies upper_ == JSVAL_INT_MAX
+ //
+ // As a second and less precise range analysis, we represent the maximal
+ // exponent taken by a value. The exponent is calculated by taking the
+ // absolute value and looking at the position of the highest bit. All
+ // exponent computation have to be over-estimations of the actual result. On
+ // the Int32 this over approximation is rectified.
+
+ MOZ_INIT_OUTSIDE_CTOR int32_t lower_;
+ MOZ_INIT_OUTSIDE_CTOR int32_t upper_;
+
+ MOZ_INIT_OUTSIDE_CTOR bool hasInt32LowerBound_;
+ MOZ_INIT_OUTSIDE_CTOR bool hasInt32UpperBound_;
+
+ MOZ_INIT_OUTSIDE_CTOR FractionalPartFlag canHaveFractionalPart_ : 1;
+ MOZ_INIT_OUTSIDE_CTOR NegativeZeroFlag canBeNegativeZero_ : 1;
+ MOZ_INIT_OUTSIDE_CTOR uint16_t max_exponent_;
+
+ // Any symbolic lower or upper bound computed for this term.
+ const SymbolicBound* symbolicLower_;
+ const SymbolicBound* symbolicUpper_;
+
+ // This function simply makes several MOZ_ASSERTs to verify the internal
+ // consistency of this range.
+ void assertInvariants() const {
+ // Basic sanity :).
+ MOZ_ASSERT(lower_ <= upper_);
+
+ // When hasInt32LowerBound_ or hasInt32UpperBound_ are false, we set
+ // lower_ and upper_ to these specific values as it simplifies the
+ // implementation in some places.
+ MOZ_ASSERT_IF(!hasInt32LowerBound_, lower_ == JSVAL_INT_MIN);
+ MOZ_ASSERT_IF(!hasInt32UpperBound_, upper_ == JSVAL_INT_MAX);
+
+ // max_exponent_ must be one of three possible things.
+ MOZ_ASSERT(max_exponent_ <= MaxFiniteExponent ||
+ max_exponent_ == IncludesInfinity ||
+ max_exponent_ == IncludesInfinityAndNaN);
+
+ // Forbid the max_exponent_ field from implying better bounds for
+ // lower_/upper_ fields. We have to add 1 to the max_exponent_ when
+ // canHaveFractionalPart_ is true in order to accomodate
+ // fractional offsets. For example, 2147483647.9 is greater than
+ // INT32_MAX, so a range containing that value will have
+ // hasInt32UpperBound_ set to false, however that value also has
+ // exponent 30, which is strictly less than MaxInt32Exponent. For
+ // another example, 1.9 has an exponent of 0 but requires upper_ to be
+ // at least 2, which has exponent 1.
+ mozilla::DebugOnly<uint32_t> adjustedExponent =
+ max_exponent_ + (canHaveFractionalPart_ ? 1 : 0);
+ MOZ_ASSERT_IF(!hasInt32LowerBound_ || !hasInt32UpperBound_,
+ adjustedExponent >= MaxInt32Exponent);
+ MOZ_ASSERT(adjustedExponent >= mozilla::FloorLog2(mozilla::Abs(upper_)));
+ MOZ_ASSERT(adjustedExponent >= mozilla::FloorLog2(mozilla::Abs(lower_)));
+
+ // The following are essentially static assertions, but FloorLog2 isn't
+ // trivially suitable for constexpr :(.
+ MOZ_ASSERT(mozilla::FloorLog2(JSVAL_INT_MIN) == MaxInt32Exponent);
+ MOZ_ASSERT(mozilla::FloorLog2(JSVAL_INT_MAX) == 30);
+ MOZ_ASSERT(mozilla::FloorLog2(UINT32_MAX) == MaxUInt32Exponent);
+ MOZ_ASSERT(mozilla::FloorLog2(0) == 0);
+ }
+
+ // Set the lower_ and hasInt32LowerBound_ values.
+ void setLowerInit(int64_t x) {
+ if (x > JSVAL_INT_MAX) {
+ lower_ = JSVAL_INT_MAX;
+ hasInt32LowerBound_ = true;
+ } else if (x < JSVAL_INT_MIN) {
+ lower_ = JSVAL_INT_MIN;
+ hasInt32LowerBound_ = false;
+ } else {
+ lower_ = int32_t(x);
+ hasInt32LowerBound_ = true;
+ }
+ }
+ // Set the upper_ and hasInt32UpperBound_ values.
+ void setUpperInit(int64_t x) {
+ if (x > JSVAL_INT_MAX) {
+ upper_ = JSVAL_INT_MAX;
+ hasInt32UpperBound_ = false;
+ } else if (x < JSVAL_INT_MIN) {
+ upper_ = JSVAL_INT_MIN;
+ hasInt32UpperBound_ = true;
+ } else {
+ upper_ = int32_t(x);
+ hasInt32UpperBound_ = true;
+ }
+ }
+
+ // Compute the least exponent value that would be compatible with the
+ // values of lower() and upper().
+ //
+ // Note:
+ // exponent of JSVAL_INT_MIN == 31
+ // exponent of JSVAL_INT_MAX == 30
+ uint16_t exponentImpliedByInt32Bounds() const {
+ // The number of bits needed to encode |max| is the power of 2 plus one.
+ uint32_t max = std::max(mozilla::Abs(lower()), mozilla::Abs(upper()));
+ uint16_t result = mozilla::FloorLog2(max);
+ MOZ_ASSERT(result ==
+ (max == 0 ? 0 : mozilla::ExponentComponent(double(max))));
+ return result;
+ }
+
+ // When converting a range which contains fractional values to a range
+ // containing only integers, the old max_exponent_ value may imply a better
+ // lower and/or upper bound than was previously available, because they no
+ // longer need to be conservative about fractional offsets and the ends of
+ // the range.
+ //
+ // Given an exponent value and pointers to the lower and upper bound values,
+ // this function refines the lower and upper bound values to the tighest
+ // bound for integer values implied by the exponent.
+ static void refineInt32BoundsByExponent(uint16_t e, int32_t* l, bool* lb,
+ int32_t* h, bool* hb) {
+ if (e < MaxInt32Exponent) {
+ // pow(2, max_exponent_+1)-1 to compute a maximum absolute value.
+ int32_t limit = (uint32_t(1) << (e + 1)) - 1;
+ *h = std::min(*h, limit);
+ *l = std::max(*l, -limit);
+ *hb = true;
+ *lb = true;
+ }
+ }
+
+ // If the value of any of the fields implies a stronger possible value for
+ // any other field, update that field to the stronger value. The range must
+ // be completely valid before and it is guaranteed to be kept valid.
+ void optimize() {
+ assertInvariants();
+
+ if (hasInt32Bounds()) {
+ // Examine lower() and upper(), and if they imply a better exponent
+ // bound than max_exponent_, set that value as the new
+ // max_exponent_.
+ uint16_t newExponent = exponentImpliedByInt32Bounds();
+ if (newExponent < max_exponent_) {
+ max_exponent_ = newExponent;
+ assertInvariants();
+ }
+
+ // If we have a completely precise range, the value is an integer,
+ // since we can only represent integers.
+ if (canHaveFractionalPart_ && lower_ == upper_) {
+ canHaveFractionalPart_ = ExcludesFractionalParts;
+ assertInvariants();
+ }
+ }
+
+ // If the range doesn't include zero, it doesn't include negative zero.
+ if (canBeNegativeZero_ && !canBeZero()) {
+ canBeNegativeZero_ = ExcludesNegativeZero;
+ assertInvariants();
+ }
+ }
+
+ // Set the range fields to the given raw values.
+ void rawInitialize(int32_t l, bool lb, int32_t h, bool hb,
+ FractionalPartFlag canHaveFractionalPart,
+ NegativeZeroFlag canBeNegativeZero, uint16_t e) {
+ lower_ = l;
+ upper_ = h;
+ hasInt32LowerBound_ = lb;
+ hasInt32UpperBound_ = hb;
+ canHaveFractionalPart_ = canHaveFractionalPart;
+ canBeNegativeZero_ = canBeNegativeZero;
+ max_exponent_ = e;
+ optimize();
+ }
+
+ // Construct a range from the given raw values.
+ Range(int32_t l, bool lb, int32_t h, bool hb,
+ FractionalPartFlag canHaveFractionalPart,
+ NegativeZeroFlag canBeNegativeZero, uint16_t e)
+ : symbolicLower_(nullptr), symbolicUpper_(nullptr) {
+ rawInitialize(l, lb, h, hb, canHaveFractionalPart, canBeNegativeZero, e);
+ }
+
+ public:
+ Range() : symbolicLower_(nullptr), symbolicUpper_(nullptr) { setUnknown(); }
+
+ Range(int64_t l, int64_t h, FractionalPartFlag canHaveFractionalPart,
+ NegativeZeroFlag canBeNegativeZero, uint16_t e)
+ : symbolicLower_(nullptr), symbolicUpper_(nullptr) {
+ set(l, h, canHaveFractionalPart, canBeNegativeZero, e);
+ }
+
+ Range(const Range& other)
+ : lower_(other.lower_),
+ upper_(other.upper_),
+ hasInt32LowerBound_(other.hasInt32LowerBound_),
+ hasInt32UpperBound_(other.hasInt32UpperBound_),
+ canHaveFractionalPart_(other.canHaveFractionalPart_),
+ canBeNegativeZero_(other.canBeNegativeZero_),
+ max_exponent_(other.max_exponent_),
+ symbolicLower_(nullptr),
+ symbolicUpper_(nullptr) {
+ assertInvariants();
+ }
+
+ // Construct a range from the given MDefinition. This differs from the
+ // MDefinition's range() method in that it describes the range of values
+ // *after* any bailout checks.
+ explicit Range(const MDefinition* def);
+
+ static Range* NewInt32Range(TempAllocator& alloc, int32_t l, int32_t h) {
+ return new (alloc) Range(l, h, ExcludesFractionalParts,
+ ExcludesNegativeZero, MaxInt32Exponent);
+ }
+
+ // Construct an int32 range containing just i. This is just a convenience
+ // wrapper around NewInt32Range.
+ static Range* NewInt32SingletonRange(TempAllocator& alloc, int32_t i) {
+ return NewInt32Range(alloc, i, i);
+ }
+
+ static Range* NewUInt32Range(TempAllocator& alloc, uint32_t l, uint32_t h) {
+ // For now, just pass them to the constructor as int64_t values.
+ // They'll become unbounded if they're not in the int32_t range.
+ return new (alloc) Range(l, h, ExcludesFractionalParts,
+ ExcludesNegativeZero, MaxUInt32Exponent);
+ }
+
+ // Construct a range containing values >= l and <= h. Note that this
+ // function treats negative zero as equal to zero, as >= and <= do. If the
+ // range includes zero, it is assumed to include negative zero too.
+ static Range* NewDoubleRange(TempAllocator& alloc, double l, double h) {
+ if (std::isnan(l) && std::isnan(h)) {
+ return nullptr;
+ }
+
+ Range* r = new (alloc) Range();
+ r->setDouble(l, h);
+ return r;
+ }
+
+ // Construct the strictest possible range containing d, or null if d is NaN.
+ // This function treats negative zero as distinct from zero, since this
+ // makes the strictest possible range containin zero a range which
+ // contains one value rather than two.
+ static Range* NewDoubleSingletonRange(TempAllocator& alloc, double d) {
+ if (std::isnan(d)) {
+ return nullptr;
+ }
+
+ Range* r = new (alloc) Range();
+ r->setDoubleSingleton(d);
+ return r;
+ }
+
+ void dump(GenericPrinter& out) const;
+ void dump() const;
+ [[nodiscard]] bool update(const Range* other);
+
+ // Unlike the other operations, unionWith is an in-place
+ // modification. This is to avoid a bunch of useless extra
+ // copying when chaining together unions when handling Phi
+ // nodes.
+ void unionWith(const Range* other);
+ static Range* intersect(TempAllocator& alloc, const Range* lhs,
+ const Range* rhs, bool* emptyRange);
+ static Range* add(TempAllocator& alloc, const Range* lhs, const Range* rhs);
+ static Range* sub(TempAllocator& alloc, const Range* lhs, const Range* rhs);
+ static Range* mul(TempAllocator& alloc, const Range* lhs, const Range* rhs);
+ static Range* and_(TempAllocator& alloc, const Range* lhs, const Range* rhs);
+ static Range* or_(TempAllocator& alloc, const Range* lhs, const Range* rhs);
+ static Range* xor_(TempAllocator& alloc, const Range* lhs, const Range* rhs);
+ static Range* not_(TempAllocator& alloc, const Range* op);
+ static Range* lsh(TempAllocator& alloc, const Range* lhs, int32_t c);
+ static Range* rsh(TempAllocator& alloc, const Range* lhs, int32_t c);
+ static Range* ursh(TempAllocator& alloc, const Range* lhs, int32_t c);
+ static Range* lsh(TempAllocator& alloc, const Range* lhs, const Range* rhs);
+ static Range* rsh(TempAllocator& alloc, const Range* lhs, const Range* rhs);
+ static Range* ursh(TempAllocator& alloc, const Range* lhs, const Range* rhs);
+ static Range* abs(TempAllocator& alloc, const Range* op);
+ static Range* min(TempAllocator& alloc, const Range* lhs, const Range* rhs);
+ static Range* max(TempAllocator& alloc, const Range* lhs, const Range* rhs);
+ static Range* floor(TempAllocator& alloc, const Range* op);
+ static Range* ceil(TempAllocator& alloc, const Range* op);
+ static Range* sign(TempAllocator& alloc, const Range* op);
+ static Range* NaNToZero(TempAllocator& alloc, const Range* op);
+
+ [[nodiscard]] static bool negativeZeroMul(const Range* lhs, const Range* rhs);
+
+ bool isUnknownInt32() const {
+ return isInt32() && lower() == INT32_MIN && upper() == INT32_MAX;
+ }
+
+ bool isUnknown() const {
+ return !hasInt32LowerBound_ && !hasInt32UpperBound_ &&
+ canHaveFractionalPart_ && canBeNegativeZero_ &&
+ max_exponent_ == IncludesInfinityAndNaN;
+ }
+
+ bool hasInt32LowerBound() const { return hasInt32LowerBound_; }
+ bool hasInt32UpperBound() const { return hasInt32UpperBound_; }
+
+ // Test whether the value is known to be within [INT32_MIN,INT32_MAX].
+ // Note that this does not necessarily mean the value is an integer.
+ bool hasInt32Bounds() const {
+ return hasInt32LowerBound() && hasInt32UpperBound();
+ }
+
+ // Test whether the value is known to be representable as an int32.
+ bool isInt32() const {
+ return hasInt32Bounds() && !canHaveFractionalPart_ && !canBeNegativeZero_;
+ }
+
+ // Test whether the given value is known to be either 0 or 1.
+ bool isBoolean() const {
+ return lower() >= 0 && upper() <= 1 && !canHaveFractionalPart_ &&
+ !canBeNegativeZero_;
+ }
+
+ bool canHaveRoundingErrors() const {
+ return canHaveFractionalPart_ || canBeNegativeZero_ ||
+ max_exponent_ >= MaxTruncatableExponent;
+ }
+
+ // Test if an integer x belongs to the range.
+ bool contains(int32_t x) const { return x >= lower_ && x <= upper_; }
+
+ // Test whether the range contains zero (of either sign).
+ bool canBeZero() const { return contains(0); }
+
+ // Test whether the range contains NaN values.
+ bool canBeNaN() const { return max_exponent_ == IncludesInfinityAndNaN; }
+
+ // Test whether the range contains infinities or NaN values.
+ bool canBeInfiniteOrNaN() const { return max_exponent_ >= IncludesInfinity; }
+
+ FractionalPartFlag canHaveFractionalPart() const {
+ return canHaveFractionalPart_;
+ }
+
+ NegativeZeroFlag canBeNegativeZero() const { return canBeNegativeZero_; }
+
+ uint16_t exponent() const {
+ MOZ_ASSERT(!canBeInfiniteOrNaN());
+ return max_exponent_;
+ }
+
+ uint16_t numBits() const {
+ return exponent() + 1; // 2^0 -> 1
+ }
+
+ // Return the lower bound. Asserts that the value has an int32 bound.
+ int32_t lower() const {
+ MOZ_ASSERT(hasInt32LowerBound());
+ return lower_;
+ }
+
+ // Return the upper bound. Asserts that the value has an int32 bound.
+ int32_t upper() const {
+ MOZ_ASSERT(hasInt32UpperBound());
+ return upper_;
+ }
+
+ // Test whether all values in this range can are finite and negative.
+ bool isFiniteNegative() const { return upper_ < 0 && !canBeInfiniteOrNaN(); }
+
+ // Test whether all values in this range can are finite and non-negative.
+ bool isFiniteNonNegative() const {
+ return lower_ >= 0 && !canBeInfiniteOrNaN();
+ }
+
+ // Test whether a value in this range can possibly be a finite
+ // negative value. Note that "negative zero" is not considered negative.
+ bool canBeFiniteNegative() const { return lower_ < 0; }
+
+ // Test whether a value in this range can possibly be a finite
+ // non-negative value.
+ bool canBeFiniteNonNegative() const { return upper_ >= 0; }
+
+ // Test whether a value in this range can have the sign bit set (not
+ // counting NaN, where the sign bit is meaningless).
+ bool canHaveSignBitSet() const {
+ return !hasInt32LowerBound() || canBeFiniteNegative() ||
+ canBeNegativeZero();
+ }
+
+ // Set this range to have a lower bound not less than x.
+ void refineLower(int32_t x) {
+ assertInvariants();
+ hasInt32LowerBound_ = true;
+ lower_ = std::max(lower_, x);
+ optimize();
+ }
+
+ // Set this range to have an upper bound not greater than x.
+ void refineUpper(int32_t x) {
+ assertInvariants();
+ hasInt32UpperBound_ = true;
+ upper_ = std::min(upper_, x);
+ optimize();
+ }
+
+ // Set this range to exclude negative zero.
+ void refineToExcludeNegativeZero() {
+ assertInvariants();
+ canBeNegativeZero_ = ExcludesNegativeZero;
+ optimize();
+ }
+
+ void setInt32(int32_t l, int32_t h) {
+ hasInt32LowerBound_ = true;
+ hasInt32UpperBound_ = true;
+ lower_ = l;
+ upper_ = h;
+ canHaveFractionalPart_ = ExcludesFractionalParts;
+ canBeNegativeZero_ = ExcludesNegativeZero;
+ max_exponent_ = exponentImpliedByInt32Bounds();
+ assertInvariants();
+ }
+
+ // Set this range to include values >= l and <= h. Note that this
+ // function treats negative zero as equal to zero, as >= and <= do. If the
+ // range includes zero, it is assumed to include negative zero too.
+ void setDouble(double l, double h);
+
+ // Set this range to the narrowest possible range containing d.
+ // This function treats negative zero as distinct from zero, since this
+ // makes the narrowest possible range containin zero a range which
+ // contains one value rather than two.
+ void setDoubleSingleton(double d);
+
+ void setUnknown() {
+ set(NoInt32LowerBound, NoInt32UpperBound, IncludesFractionalParts,
+ IncludesNegativeZero, IncludesInfinityAndNaN);
+ MOZ_ASSERT(isUnknown());
+ }
+
+ void set(int64_t l, int64_t h, FractionalPartFlag canHaveFractionalPart,
+ NegativeZeroFlag canBeNegativeZero, uint16_t e) {
+ max_exponent_ = e;
+ canHaveFractionalPart_ = canHaveFractionalPart;
+ canBeNegativeZero_ = canBeNegativeZero;
+ setLowerInit(l);
+ setUpperInit(h);
+ optimize();
+ }
+
+ // Make the lower end of this range at least INT32_MIN, and make
+ // the upper end of this range at most INT32_MAX.
+ void clampToInt32();
+
+ // If this range exceeds int32_t range, at either or both ends, change
+ // it to int32_t range. Otherwise do nothing.
+ void wrapAroundToInt32();
+
+ // If this range exceeds [0, 32) range, at either or both ends, change
+ // it to the [0, 32) range. Otherwise do nothing.
+ void wrapAroundToShiftCount();
+
+ // If this range exceeds [0, 1] range, at either or both ends, change
+ // it to the [0, 1] range. Otherwise do nothing.
+ void wrapAroundToBoolean();
+
+ const SymbolicBound* symbolicLower() const { return symbolicLower_; }
+ const SymbolicBound* symbolicUpper() const { return symbolicUpper_; }
+
+ void setSymbolicLower(SymbolicBound* bound) { symbolicLower_ = bound; }
+ void setSymbolicUpper(SymbolicBound* bound) { symbolicUpper_ = bound; }
+};
+
+} // namespace jit
+} // namespace js
+
+#endif /* jit_RangeAnalysis_h */
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