/3rd_party/llvm/lib/CodeGen/LiveIntervalUnion.h
https://code.google.com/p/softart/ · C++ Header · 210 lines · 115 code · 42 blank · 53 comment · 12 complexity · 3fcf73dc735998209b4a05a48b4fd427 MD5 · raw file
- //===-- LiveIntervalUnion.h - Live interval union data struct --*- C++ -*--===//
- //
- // The LLVM Compiler Infrastructure
- //
- // This file is distributed under the University of Illinois Open Source
- // License. See LICENSE.TXT for details.
- //
- //===----------------------------------------------------------------------===//
- //
- // LiveIntervalUnion is a union of live segments across multiple live virtual
- // registers. This may be used during coalescing to represent a congruence
- // class, or during register allocation to model liveness of a physical
- // register.
- //
- //===----------------------------------------------------------------------===//
- #ifndef LLVM_CODEGEN_LIVEINTERVALUNION
- #define LLVM_CODEGEN_LIVEINTERVALUNION
- #include "llvm/ADT/IntervalMap.h"
- #include "llvm/CodeGen/LiveInterval.h"
- namespace llvm {
- class MachineLoopRange;
- class TargetRegisterInfo;
- #ifndef NDEBUG
- // forward declaration
- template <unsigned Element> class SparseBitVector;
- typedef SparseBitVector<128> LiveVirtRegBitSet;
- #endif
- /// Compare a live virtual register segment to a LiveIntervalUnion segment.
- inline bool
- overlap(const LiveRange &VRSeg,
- const IntervalMap<SlotIndex, LiveInterval*>::const_iterator &LUSeg) {
- return VRSeg.start < LUSeg.stop() && LUSeg.start() < VRSeg.end;
- }
- /// Union of live intervals that are strong candidates for coalescing into a
- /// single register (either physical or virtual depending on the context). We
- /// expect the constituent live intervals to be disjoint, although we may
- /// eventually make exceptions to handle value-based interference.
- class LiveIntervalUnion {
- // A set of live virtual register segments that supports fast insertion,
- // intersection, and removal.
- // Mapping SlotIndex intervals to virtual register numbers.
- typedef IntervalMap<SlotIndex, LiveInterval*> LiveSegments;
- public:
- // SegmentIter can advance to the next segment ordered by starting position
- // which may belong to a different live virtual register. We also must be able
- // to reach the current segment's containing virtual register.
- typedef LiveSegments::iterator SegmentIter;
- // LiveIntervalUnions share an external allocator.
- typedef LiveSegments::Allocator Allocator;
- class Query;
- private:
- unsigned Tag; // unique tag for current contents.
- LiveSegments Segments; // union of virtual reg segments
- public:
- explicit LiveIntervalUnion(Allocator &a) : Tag(0), Segments(a) {}
- // Iterate over all segments in the union of live virtual registers ordered
- // by their starting position.
- SegmentIter begin() { return Segments.begin(); }
- SegmentIter end() { return Segments.end(); }
- SegmentIter find(SlotIndex x) { return Segments.find(x); }
- bool empty() const { return Segments.empty(); }
- SlotIndex startIndex() const { return Segments.start(); }
- // Provide public access to the underlying map to allow overlap iteration.
- typedef LiveSegments Map;
- const Map &getMap() { return Segments; }
- /// getTag - Return an opaque tag representing the current state of the union.
- unsigned getTag() const { return Tag; }
- /// changedSince - Return true if the union change since getTag returned tag.
- bool changedSince(unsigned tag) const { return tag != Tag; }
- // Add a live virtual register to this union and merge its segments.
- void unify(LiveInterval &VirtReg);
- // Remove a live virtual register's segments from this union.
- void extract(LiveInterval &VirtReg);
- // Remove all inserted virtual registers.
- void clear() { Segments.clear(); ++Tag; }
- // Print union, using TRI to translate register names
- void print(raw_ostream &OS, const TargetRegisterInfo *TRI) const;
- #ifndef NDEBUG
- // Verify the live intervals in this union and add them to the visited set.
- void verify(LiveVirtRegBitSet& VisitedVRegs);
- #endif
- /// Query interferences between a single live virtual register and a live
- /// interval union.
- class Query {
- LiveIntervalUnion *LiveUnion;
- LiveInterval *VirtReg;
- LiveInterval::iterator VirtRegI; // current position in VirtReg
- SegmentIter LiveUnionI; // current position in LiveUnion
- SmallVector<LiveInterval*,4> InterferingVRegs;
- bool CheckedFirstInterference;
- bool SeenAllInterferences;
- bool SeenUnspillableVReg;
- unsigned Tag, UserTag;
- public:
- Query(): LiveUnion(), VirtReg(), Tag(0), UserTag(0) {}
- Query(LiveInterval *VReg, LiveIntervalUnion *LIU):
- LiveUnion(LIU), VirtReg(VReg), CheckedFirstInterference(false),
- SeenAllInterferences(false), SeenUnspillableVReg(false)
- {}
- void clear() {
- LiveUnion = NULL;
- VirtReg = NULL;
- InterferingVRegs.clear();
- CheckedFirstInterference = false;
- SeenAllInterferences = false;
- SeenUnspillableVReg = false;
- Tag = 0;
- UserTag = 0;
- }
- void init(unsigned UTag, LiveInterval *VReg, LiveIntervalUnion *LIU) {
- assert(VReg && LIU && "Invalid arguments");
- if (UserTag == UTag && VirtReg == VReg &&
- LiveUnion == LIU && !LIU->changedSince(Tag)) {
- // Retain cached results, e.g. firstInterference.
- return;
- }
- clear();
- LiveUnion = LIU;
- VirtReg = VReg;
- Tag = LIU->getTag();
- UserTag = UTag;
- }
- LiveInterval &virtReg() const {
- assert(VirtReg && "uninitialized");
- return *VirtReg;
- }
- // Does this live virtual register interfere with the union?
- bool checkInterference() { return collectInterferingVRegs(1); }
- // Count the virtual registers in this union that interfere with this
- // query's live virtual register, up to maxInterferingRegs.
- unsigned collectInterferingVRegs(unsigned MaxInterferingRegs = UINT_MAX);
- // Was this virtual register visited during collectInterferingVRegs?
- bool isSeenInterference(LiveInterval *VReg) const;
- // Did collectInterferingVRegs collect all interferences?
- bool seenAllInterferences() const { return SeenAllInterferences; }
- // Did collectInterferingVRegs encounter an unspillable vreg?
- bool seenUnspillableVReg() const { return SeenUnspillableVReg; }
- // Vector generated by collectInterferingVRegs.
- const SmallVectorImpl<LiveInterval*> &interferingVRegs() const {
- return InterferingVRegs;
- }
- /// checkLoopInterference - Return true if there is interference overlapping
- /// Loop.
- bool checkLoopInterference(MachineLoopRange*);
- private:
- Query(const Query&); // DO NOT IMPLEMENT
- void operator=(const Query&); // DO NOT IMPLEMENT
- };
- // Array of LiveIntervalUnions.
- class Array {
- unsigned Size;
- LiveIntervalUnion *LIUs;
- public:
- Array() : Size(0), LIUs(0) {}
- ~Array() { clear(); }
- // Initialize the array to have Size entries.
- // Reuse an existing allocation if the size matches.
- void init(LiveIntervalUnion::Allocator&, unsigned Size);
- unsigned size() const { return Size; }
- void clear();
- LiveIntervalUnion& operator[](unsigned idx) {
- assert(idx < Size && "idx out of bounds");
- return LIUs[idx];
- }
- };
- };
- } // end namespace llvm
- #endif // !defined(LLVM_CODEGEN_LIVEINTERVALUNION)