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author | Matt A. Tobin <mattatobin@localhost.localdomain> | 2018-02-02 04:16:08 -0500 |
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committer | Matt A. Tobin <mattatobin@localhost.localdomain> | 2018-02-02 04:16:08 -0500 |
commit | 5f8de423f190bbb79a62f804151bc24824fa32d8 (patch) | |
tree | 10027f336435511475e392454359edea8e25895d /js/src/jit/BacktrackingAllocator.h | |
parent | 49ee0794b5d912db1f95dce6eb52d781dc210db5 (diff) | |
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Add m-esr52 at 52.6.0
Diffstat (limited to 'js/src/jit/BacktrackingAllocator.h')
-rw-r--r-- | js/src/jit/BacktrackingAllocator.h | 816 |
1 files changed, 816 insertions, 0 deletions
diff --git a/js/src/jit/BacktrackingAllocator.h b/js/src/jit/BacktrackingAllocator.h new file mode 100644 index 000000000..6d14ffacd --- /dev/null +++ b/js/src/jit/BacktrackingAllocator.h @@ -0,0 +1,816 @@ +/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*- + * vim: set ts=8 sts=4 et sw=4 tw=99: + * 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_BacktrackingAllocator_h +#define jit_BacktrackingAllocator_h + +#include "mozilla/Array.h" + +#include "ds/PriorityQueue.h" +#include "ds/SplayTree.h" +#include "jit/RegisterAllocator.h" +#include "jit/StackSlotAllocator.h" + +// Backtracking priority queue based register allocator based on that described +// in the following blog post: +// +// http://blog.llvm.org/2011/09/greedy-register-allocation-in-llvm-30.html + +namespace js { +namespace jit { + +class Requirement +{ + public: + enum Kind { + NONE, + REGISTER, + FIXED, + MUST_REUSE_INPUT + }; + + Requirement() + : kind_(NONE) + { } + + explicit Requirement(Kind kind) + : kind_(kind) + { + // These have dedicated constructors. + MOZ_ASSERT(kind != FIXED && kind != MUST_REUSE_INPUT); + } + + Requirement(Kind kind, CodePosition at) + : kind_(kind), + position_(at) + { + // These have dedicated constructors. + MOZ_ASSERT(kind != FIXED && kind != MUST_REUSE_INPUT); + } + + explicit Requirement(LAllocation fixed) + : kind_(FIXED), + allocation_(fixed) + { + MOZ_ASSERT(!fixed.isBogus() && !fixed.isUse()); + } + + // Only useful as a hint, encodes where the fixed requirement is used to + // avoid allocating a fixed register too early. + Requirement(LAllocation fixed, CodePosition at) + : kind_(FIXED), + allocation_(fixed), + position_(at) + { + MOZ_ASSERT(!fixed.isBogus() && !fixed.isUse()); + } + + Requirement(uint32_t vreg, CodePosition at) + : kind_(MUST_REUSE_INPUT), + allocation_(LUse(vreg, LUse::ANY)), + position_(at) + { } + + Kind kind() const { + return kind_; + } + + LAllocation allocation() const { + MOZ_ASSERT(!allocation_.isBogus() && !allocation_.isUse()); + return allocation_; + } + + uint32_t virtualRegister() const { + MOZ_ASSERT(allocation_.isUse()); + MOZ_ASSERT(kind() == MUST_REUSE_INPUT); + return allocation_.toUse()->virtualRegister(); + } + + CodePosition pos() const { + return position_; + } + + int priority() const; + + MOZ_MUST_USE bool merge(const Requirement& newRequirement) { + // Merge newRequirement with any existing requirement, returning false + // if the new and old requirements conflict. + MOZ_ASSERT(newRequirement.kind() != Requirement::MUST_REUSE_INPUT); + + if (newRequirement.kind() == Requirement::FIXED) { + if (kind() == Requirement::FIXED) + return newRequirement.allocation() == allocation(); + *this = newRequirement; + return true; + } + + MOZ_ASSERT(newRequirement.kind() == Requirement::REGISTER); + if (kind() == Requirement::FIXED) + return allocation().isRegister(); + + *this = newRequirement; + return true; + } + + void dump() const; + + private: + Kind kind_; + LAllocation allocation_; + CodePosition position_; +}; + +struct UsePosition : public TempObject, + public InlineForwardListNode<UsePosition> +{ + private: + // Packed LUse* with a copy of the LUse::Policy value, in order to avoid + // making cache misses while reaching out to the policy value. + uintptr_t use_; + + void setUse(LUse* use) { + // Assert that we can safely pack the LUse policy in the last 2 bits of + // the LUse pointer. + static_assert((LUse::ANY | LUse::REGISTER | LUse::FIXED | LUse::KEEPALIVE) <= 0x3, + "Cannot pack the LUse::Policy value on 32 bits architectures."); + + // RECOVERED_INPUT is used by snapshots and ignored when building the + // liveness information. Thus we can safely assume that no such value + // would be seen. + MOZ_ASSERT(use->policy() != LUse::RECOVERED_INPUT); + use_ = uintptr_t(use) | (use->policy() & 0x3); + } + + public: + CodePosition pos; + + LUse* use() const { + return reinterpret_cast<LUse*>(use_ & ~0x3); + } + + LUse::Policy usePolicy() const { + LUse::Policy policy = LUse::Policy(use_ & 0x3); + MOZ_ASSERT(use()->policy() == policy); + return policy; + } + + UsePosition(LUse* use, CodePosition pos) : + pos(pos) + { + // Verify that the usedAtStart() flag is consistent with the + // subposition. For now ignore fixed registers, because they + // are handled specially around calls. + MOZ_ASSERT_IF(!use->isFixedRegister(), + pos.subpos() == (use->usedAtStart() + ? CodePosition::INPUT + : CodePosition::OUTPUT)); + setUse(use); + } +}; + +typedef InlineForwardListIterator<UsePosition> UsePositionIterator; + +// Backtracking allocator data structures overview. +// +// LiveRange: A continuous range of positions where a virtual register is live. +// LiveBundle: A set of LiveRanges which do not overlap. +// VirtualRegister: A set of all LiveRanges used for some LDefinition. +// +// The allocator first performs a liveness ananlysis on the LIR graph which +// constructs LiveRanges for each VirtualRegister, determining where the +// registers are live. +// +// The ranges are then bundled together according to heuristics, and placed on +// the allocation queue. +// +// As bundles are removed from the allocation queue, we attempt to find a +// physical register or stack slot allocation for all ranges in the removed +// bundle, possibly evicting already-allocated bundles. See processBundle() +// for details. +// +// If we are not able to allocate a bundle, it is split according to heuristics +// into two or more smaller bundles which cover all the ranges of the original. +// These smaller bundles are then allocated independently. + +class LiveBundle; + +class LiveRange : public TempObject +{ + public: + // Linked lists are used to keep track of the ranges in each LiveBundle and + // VirtualRegister. Since a LiveRange may be in two lists simultaneously, use + // these auxiliary classes to keep things straight. + class BundleLink : public InlineForwardListNode<BundleLink> {}; + class RegisterLink : public InlineForwardListNode<RegisterLink> {}; + + typedef InlineForwardListIterator<BundleLink> BundleLinkIterator; + typedef InlineForwardListIterator<RegisterLink> RegisterLinkIterator; + + // Links in the lists in LiveBundle and VirtualRegister. + BundleLink bundleLink; + RegisterLink registerLink; + + static LiveRange* get(BundleLink* link) { + return reinterpret_cast<LiveRange*>(reinterpret_cast<uint8_t*>(link) - + offsetof(LiveRange, bundleLink)); + } + static LiveRange* get(RegisterLink* link) { + return reinterpret_cast<LiveRange*>(reinterpret_cast<uint8_t*>(link) - + offsetof(LiveRange, registerLink)); + } + + struct Range + { + // The beginning of this range, inclusive. + CodePosition from; + + // The end of this range, exclusive. + CodePosition to; + + Range() {} + + Range(CodePosition from, CodePosition to) + : from(from), to(to) + { + MOZ_ASSERT(!empty()); + } + + bool empty() { + MOZ_ASSERT(from <= to); + return from == to; + } + }; + + private: + // The virtual register this range is for, or zero if this does not have a + // virtual register (for example, it is in the callRanges bundle). + uint32_t vreg_; + + // The bundle containing this range, null if liveness information is being + // constructed and we haven't started allocating bundles yet. + LiveBundle* bundle_; + + // The code positions in this range. + Range range_; + + // All uses of the virtual register in this range, ordered by location. + InlineForwardList<UsePosition> uses_; + + // Whether this range contains the virtual register's definition. + bool hasDefinition_; + + LiveRange(uint32_t vreg, Range range) + : vreg_(vreg), bundle_(nullptr), range_(range), hasDefinition_(false) + { + MOZ_ASSERT(!range.empty()); + } + + public: + static LiveRange* FallibleNew(TempAllocator& alloc, uint32_t vreg, + CodePosition from, CodePosition to) + { + return new(alloc.fallible()) LiveRange(vreg, Range(from, to)); + } + + uint32_t vreg() const { + MOZ_ASSERT(hasVreg()); + return vreg_; + } + bool hasVreg() const { + return vreg_ != 0; + } + + LiveBundle* bundle() const { + return bundle_; + } + + CodePosition from() const { + return range_.from; + } + CodePosition to() const { + return range_.to; + } + bool covers(CodePosition pos) const { + return pos >= from() && pos < to(); + } + + // Whether this range wholly contains other. + bool contains(LiveRange* other) const; + + // Intersect this range with other, returning the subranges of this + // that are before, inside, or after other. + void intersect(LiveRange* other, Range* pre, Range* inside, Range* post) const; + + // Whether this range has any intersection with other. + bool intersects(LiveRange* other) const; + + UsePositionIterator usesBegin() const { + return uses_.begin(); + } + UsePosition* lastUse() const { + return uses_.back(); + } + bool hasUses() const { + return !!usesBegin(); + } + UsePosition* popUse() { + return uses_.popFront(); + } + + bool hasDefinition() const { + return hasDefinition_; + } + + void setFrom(CodePosition from) { + range_.from = from; + MOZ_ASSERT(!range_.empty()); + } + void setTo(CodePosition to) { + range_.to = to; + MOZ_ASSERT(!range_.empty()); + } + + void setBundle(LiveBundle* bundle) { + bundle_ = bundle; + } + + void addUse(UsePosition* use); + void distributeUses(LiveRange* other); + + void setHasDefinition() { + MOZ_ASSERT(!hasDefinition_); + hasDefinition_ = true; + } + +#ifdef JS_JITSPEW + // Return a string describing this range. + UniqueChars toString() const; +#endif + + // Comparator for use in range splay trees. + static int compare(LiveRange* v0, LiveRange* v1) { + // LiveRange includes 'from' but excludes 'to'. + if (v0->to() <= v1->from()) + return -1; + if (v0->from() >= v1->to()) + return 1; + return 0; + } +}; + +// Tracks information about bundles that should all be spilled to the same +// physical location. At the beginning of allocation, each bundle has its own +// spill set. As bundles are split, the new smaller bundles continue to use the +// same spill set. +class SpillSet : public TempObject +{ + // All bundles with this spill set which have been spilled. All bundles in + // this list will be given the same physical slot. + Vector<LiveBundle*, 1, JitAllocPolicy> list_; + + explicit SpillSet(TempAllocator& alloc) + : list_(alloc) + { } + + public: + static SpillSet* New(TempAllocator& alloc) { + return new(alloc) SpillSet(alloc); + } + + MOZ_MUST_USE bool addSpilledBundle(LiveBundle* bundle) { + return list_.append(bundle); + } + size_t numSpilledBundles() const { + return list_.length(); + } + LiveBundle* spilledBundle(size_t i) const { + return list_[i]; + } + + void setAllocation(LAllocation alloc); +}; + +// A set of live ranges which are all pairwise disjoint. The register allocator +// attempts to find allocations for an entire bundle, and if it fails the +// bundle will be broken into smaller ones which are allocated independently. +class LiveBundle : public TempObject +{ + // Set to use if this bundle or one it is split into is spilled. + SpillSet* spill_; + + // All the ranges in this set, ordered by location. + InlineForwardList<LiveRange::BundleLink> ranges_; + + // Allocation to use for ranges in this set, bogus if unallocated or spilled + // and not yet given a physical stack slot. + LAllocation alloc_; + + // Bundle which entirely contains this one and has no register uses. This + // may or may not be spilled by the allocator, but it can be spilled and + // will not be split. + LiveBundle* spillParent_; + + LiveBundle(SpillSet* spill, LiveBundle* spillParent) + : spill_(spill), spillParent_(spillParent) + { } + + public: + static LiveBundle* FallibleNew(TempAllocator& alloc, SpillSet* spill, LiveBundle* spillParent) + { + return new(alloc.fallible()) LiveBundle(spill, spillParent); + } + + SpillSet* spillSet() const { + return spill_; + } + void setSpillSet(SpillSet* spill) { + spill_ = spill; + } + + LiveRange::BundleLinkIterator rangesBegin() const { + return ranges_.begin(); + } + bool hasRanges() const { + return !!rangesBegin(); + } + LiveRange* firstRange() const { + return LiveRange::get(*rangesBegin()); + } + LiveRange* lastRange() const { + return LiveRange::get(ranges_.back()); + } + LiveRange* rangeFor(CodePosition pos) const; + void removeRange(LiveRange* range); + void removeRangeAndIncrementIterator(LiveRange::BundleLinkIterator& iter) { + ranges_.removeAndIncrement(iter); + } + void addRange(LiveRange* range); + MOZ_MUST_USE bool addRange(TempAllocator& alloc, uint32_t vreg, + CodePosition from, CodePosition to); + MOZ_MUST_USE bool addRangeAndDistributeUses(TempAllocator& alloc, LiveRange* oldRange, + CodePosition from, CodePosition to); + LiveRange* popFirstRange(); +#ifdef DEBUG + size_t numRanges() const; +#endif + + LAllocation allocation() const { + return alloc_; + } + void setAllocation(LAllocation alloc) { + alloc_ = alloc; + } + + LiveBundle* spillParent() const { + return spillParent_; + } + +#ifdef JS_JITSPEW + // Return a string describing this bundle. + UniqueChars toString() const; +#endif +}; + +// Information about the allocation for a virtual register. +class VirtualRegister +{ + // Instruction which defines this register. + LNode* ins_; + + // Definition in the instruction for this register. + LDefinition* def_; + + // All live ranges for this register. These may overlap each other, and are + // ordered by their start position. + InlineForwardList<LiveRange::RegisterLink> ranges_; + + // Whether def_ is a temp or an output. + bool isTemp_; + + // Whether this vreg is an input for some phi. This use is not reflected in + // any range on the vreg. + bool usedByPhi_; + + // If this register's definition is MUST_REUSE_INPUT, whether a copy must + // be introduced before the definition that relaxes the policy. + bool mustCopyInput_; + + void operator=(const VirtualRegister&) = delete; + VirtualRegister(const VirtualRegister&) = delete; + + public: + explicit VirtualRegister() + { + // Note: This class is zeroed before it is constructed. + } + + void init(LNode* ins, LDefinition* def, bool isTemp) { + MOZ_ASSERT(!ins_); + ins_ = ins; + def_ = def; + isTemp_ = isTemp; + } + + LNode* ins() const { + return ins_; + } + LDefinition* def() const { + return def_; + } + LDefinition::Type type() const { + return def()->type(); + } + uint32_t vreg() const { + return def()->virtualRegister(); + } + bool isCompatible(const AnyRegister& r) const { + return def_->isCompatibleReg(r); + } + bool isCompatible(const VirtualRegister& vr) const { + return def_->isCompatibleDef(*vr.def_); + } + bool isTemp() const { + return isTemp_; + } + + void setUsedByPhi() { + usedByPhi_ = true; + } + bool usedByPhi() { + return usedByPhi_; + } + + void setMustCopyInput() { + mustCopyInput_ = true; + } + bool mustCopyInput() { + return mustCopyInput_; + } + + LiveRange::RegisterLinkIterator rangesBegin() const { + return ranges_.begin(); + } + LiveRange::RegisterLinkIterator rangesBegin(LiveRange* range) const { + return ranges_.begin(&range->registerLink); + } + bool hasRanges() const { + return !!rangesBegin(); + } + LiveRange* firstRange() const { + return LiveRange::get(*rangesBegin()); + } + LiveRange* lastRange() const { + return LiveRange::get(ranges_.back()); + } + LiveRange* rangeFor(CodePosition pos, bool preferRegister = false) const; + void removeRange(LiveRange* range); + void addRange(LiveRange* range); + + void removeRangeAndIncrement(LiveRange::RegisterLinkIterator& iter) { + ranges_.removeAndIncrement(iter); + } + + LiveBundle* firstBundle() const { + return firstRange()->bundle(); + } + + MOZ_MUST_USE bool addInitialRange(TempAllocator& alloc, CodePosition from, CodePosition to); + void addInitialUse(UsePosition* use); + void setInitialDefinition(CodePosition from); +}; + +// A sequence of code positions, for tellings BacktrackingAllocator::splitAt +// where to split. +typedef js::Vector<CodePosition, 4, SystemAllocPolicy> SplitPositionVector; + +class BacktrackingAllocator : protected RegisterAllocator +{ + friend class C1Spewer; + friend class JSONSpewer; + + // This flag is set when testing new allocator modifications. + bool testbed; + + BitSet* liveIn; + FixedList<VirtualRegister> vregs; + + // Allocation state. + StackSlotAllocator stackSlotAllocator; + + // Priority queue element: a bundle and the associated priority. + struct QueueItem + { + LiveBundle* bundle; + + QueueItem(LiveBundle* bundle, size_t priority) + : bundle(bundle), priority_(priority) + {} + + static size_t priority(const QueueItem& v) { + return v.priority_; + } + + private: + size_t priority_; + }; + + PriorityQueue<QueueItem, QueueItem, 0, SystemAllocPolicy> allocationQueue; + + typedef SplayTree<LiveRange*, LiveRange> LiveRangeSet; + + // Each physical register is associated with the set of ranges over which + // that register is currently allocated. + struct PhysicalRegister { + bool allocatable; + AnyRegister reg; + LiveRangeSet allocations; + + PhysicalRegister() : allocatable(false) {} + }; + mozilla::Array<PhysicalRegister, AnyRegister::Total> registers; + + // Ranges of code which are considered to be hot, for which good allocation + // should be prioritized. + LiveRangeSet hotcode; + + struct CallRange : public TempObject, public InlineListNode<CallRange> { + LiveRange::Range range; + + CallRange(CodePosition from, CodePosition to) + : range(from, to) + {} + + // Comparator for use in splay tree. + static int compare(CallRange* v0, CallRange* v1) { + if (v0->range.to <= v1->range.from) + return -1; + if (v0->range.from >= v1->range.to) + return 1; + return 0; + } + }; + + // Ranges where all registers must be spilled due to call instructions. + typedef InlineList<CallRange> CallRangeList; + CallRangeList callRangesList; + SplayTree<CallRange*, CallRange> callRanges; + + // Information about an allocated stack slot. + struct SpillSlot : public TempObject, public InlineForwardListNode<SpillSlot> { + LStackSlot alloc; + LiveRangeSet allocated; + + SpillSlot(uint32_t slot, LifoAlloc* alloc) + : alloc(slot), allocated(alloc) + {} + }; + typedef InlineForwardList<SpillSlot> SpillSlotList; + + // All allocated slots of each width. + SpillSlotList normalSlots, doubleSlots, quadSlots; + + public: + BacktrackingAllocator(MIRGenerator* mir, LIRGenerator* lir, LIRGraph& graph, bool testbed) + : RegisterAllocator(mir, lir, graph), + testbed(testbed), + liveIn(nullptr), + callRanges(nullptr) + { } + + MOZ_MUST_USE bool go(); + + private: + + typedef Vector<LiveRange*, 4, SystemAllocPolicy> LiveRangeVector; + typedef Vector<LiveBundle*, 4, SystemAllocPolicy> LiveBundleVector; + + // Liveness methods. + MOZ_MUST_USE bool init(); + MOZ_MUST_USE bool buildLivenessInfo(); + + MOZ_MUST_USE bool addInitialFixedRange(AnyRegister reg, CodePosition from, CodePosition to); + + VirtualRegister& vreg(const LDefinition* def) { + return vregs[def->virtualRegister()]; + } + VirtualRegister& vreg(const LAllocation* alloc) { + MOZ_ASSERT(alloc->isUse()); + return vregs[alloc->toUse()->virtualRegister()]; + } + + // Allocation methods. + MOZ_MUST_USE bool tryMergeBundles(LiveBundle* bundle0, LiveBundle* bundle1); + MOZ_MUST_USE bool tryMergeReusedRegister(VirtualRegister& def, VirtualRegister& input); + MOZ_MUST_USE bool mergeAndQueueRegisters(); + MOZ_MUST_USE bool tryAllocateFixed(LiveBundle* bundle, Requirement requirement, + bool* success, bool* pfixed, LiveBundleVector& conflicting); + MOZ_MUST_USE bool tryAllocateNonFixed(LiveBundle* bundle, Requirement requirement, + Requirement hint, bool* success, bool* pfixed, + LiveBundleVector& conflicting); + MOZ_MUST_USE bool processBundle(MIRGenerator* mir, LiveBundle* bundle); + MOZ_MUST_USE bool computeRequirement(LiveBundle* bundle, Requirement *prequirement, + Requirement *phint); + MOZ_MUST_USE bool tryAllocateRegister(PhysicalRegister& r, LiveBundle* bundle, bool* success, + bool* pfixed, LiveBundleVector& conflicting); + MOZ_MUST_USE bool evictBundle(LiveBundle* bundle); + MOZ_MUST_USE bool splitAndRequeueBundles(LiveBundle* bundle, + const LiveBundleVector& newBundles); + MOZ_MUST_USE bool spill(LiveBundle* bundle); + + bool isReusedInput(LUse* use, LNode* ins, bool considerCopy); + bool isRegisterUse(UsePosition* use, LNode* ins, bool considerCopy = false); + bool isRegisterDefinition(LiveRange* range); + MOZ_MUST_USE bool pickStackSlot(SpillSet* spill); + MOZ_MUST_USE bool insertAllRanges(LiveRangeSet& set, LiveBundle* bundle); + + // Reification methods. + MOZ_MUST_USE bool pickStackSlots(); + MOZ_MUST_USE bool resolveControlFlow(); + MOZ_MUST_USE bool reifyAllocations(); + MOZ_MUST_USE bool populateSafepoints(); + MOZ_MUST_USE bool annotateMoveGroups(); + MOZ_MUST_USE bool deadRange(LiveRange* range); + size_t findFirstNonCallSafepoint(CodePosition from); + size_t findFirstSafepoint(CodePosition pos, size_t startFrom); + void addLiveRegistersForRange(VirtualRegister& reg, LiveRange* range); + + MOZ_MUST_USE bool addMove(LMoveGroup* moves, LiveRange* from, LiveRange* to, + LDefinition::Type type) { + LAllocation fromAlloc = from->bundle()->allocation(); + LAllocation toAlloc = to->bundle()->allocation(); + MOZ_ASSERT(fromAlloc != toAlloc); + return moves->add(fromAlloc, toAlloc, type); + } + + MOZ_MUST_USE bool moveInput(LInstruction* ins, LiveRange* from, LiveRange* to, + LDefinition::Type type) { + if (from->bundle()->allocation() == to->bundle()->allocation()) + return true; + LMoveGroup* moves = getInputMoveGroup(ins); + return addMove(moves, from, to, type); + } + + MOZ_MUST_USE bool moveAfter(LInstruction* ins, LiveRange* from, LiveRange* to, + LDefinition::Type type) { + if (from->bundle()->allocation() == to->bundle()->allocation()) + return true; + LMoveGroup* moves = getMoveGroupAfter(ins); + return addMove(moves, from, to, type); + } + + MOZ_MUST_USE bool moveAtExit(LBlock* block, LiveRange* from, LiveRange* to, + LDefinition::Type type) { + if (from->bundle()->allocation() == to->bundle()->allocation()) + return true; + LMoveGroup* moves = block->getExitMoveGroup(alloc()); + return addMove(moves, from, to, type); + } + + MOZ_MUST_USE bool moveAtEntry(LBlock* block, LiveRange* from, LiveRange* to, + LDefinition::Type type) { + if (from->bundle()->allocation() == to->bundle()->allocation()) + return true; + LMoveGroup* moves = block->getEntryMoveGroup(alloc()); + return addMove(moves, from, to, type); + } + + // Debugging methods. + void dumpAllocations(); + + struct PrintLiveRange; + + bool minimalDef(LiveRange* range, LNode* ins); + bool minimalUse(LiveRange* range, UsePosition* use); + bool minimalBundle(LiveBundle* bundle, bool* pfixed = nullptr); + + // Heuristic methods. + + size_t computePriority(LiveBundle* bundle); + size_t computeSpillWeight(LiveBundle* bundle); + + size_t maximumSpillWeight(const LiveBundleVector& bundles); + + MOZ_MUST_USE bool chooseBundleSplit(LiveBundle* bundle, bool fixed, LiveBundle* conflict); + + MOZ_MUST_USE bool splitAt(LiveBundle* bundle, const SplitPositionVector& splitPositions); + MOZ_MUST_USE bool trySplitAcrossHotcode(LiveBundle* bundle, bool* success); + MOZ_MUST_USE bool trySplitAfterLastRegisterUse(LiveBundle* bundle, LiveBundle* conflict, + bool* success); + MOZ_MUST_USE bool trySplitBeforeFirstRegisterUse(LiveBundle* bundle, LiveBundle* conflict, + bool* success); + MOZ_MUST_USE bool splitAcrossCalls(LiveBundle* bundle); + + bool compilingWasm() { + return mir->info().compilingWasm(); + } + + void dumpVregs(); +}; + +} // namespace jit +} // namespace js + +#endif /* jit_BacktrackingAllocator_h */ |