#ifndef LLVM_CODEGEN_LIVEINTERVALUNION
#define LLVM_CODEGEN_LIVEINTERVALUNION
+#include "llvm/ADT/IntervalMap.h"
#include "llvm/CodeGen/LiveInterval.h"
-#include <vector>
-#include <set>
namespace llvm {
-// A LiveSegment is a copy of a LiveRange object used within
-// LiveIntervalUnion. LiveSegment additionally contains a pointer to its
-// original live virtual register (LiveInterval). This allows quick lookup of
-// the live virtual register as we iterate over live segments in a union. Note
-// that LiveRange is misnamed and actually represents only a single contiguous
-// interval within a virtual register's liveness. To limit confusion, in this
-// file we refer it as a live segment.
-struct LiveSegment {
- SlotIndex start;
- SlotIndex end;
- LiveInterval *liveVirtReg;
-
- LiveSegment(SlotIndex s, SlotIndex e, LiveInterval &lvr)
- : start(s), end(e), liveVirtReg(&lvr) {}
-
- bool operator==(const LiveSegment &ls) const {
- return start == ls.start && end == ls.end && liveVirtReg == ls.liveVirtReg;
- }
-
- bool operator!=(const LiveSegment &ls) const {
- return !operator==(ls);
- }
-
- bool operator<(const LiveSegment &ls) const {
- return start < ls.start || (start == ls.start && end < ls.end);
- }
-};
-
-/// Compare a live virtual register segment to a LiveIntervalUnion segment.
-inline bool overlap(const LiveRange &lvrSeg, const LiveSegment &liuSeg) {
- return lvrSeg.start < liuSeg.end && liuSeg.start < lvrSeg.end;
-}
+class MachineLoopRange;
+class TargetRegisterInfo;
-inline bool operator<(SlotIndex V, const LiveSegment &ls) {
- return V < ls.start;
-}
+#ifndef NDEBUG
+// forward declaration
+template <unsigned Element> class SparseBitVector;
+typedef SparseBitVector<128> LiveVirtRegBitSet;
+#endif
-inline bool operator<(const LiveSegment &ls, SlotIndex V) {
- return ls.start < V;
+/// 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
/// eventually make exceptions to handle value-based interference.
class LiveIntervalUnion {
// A set of live virtual register segments that supports fast insertion,
- // intersection, and removal.
- //
- // FIXME: std::set is a placeholder until we decide how to
- // efficiently represent it. Probably need to roll our own B-tree.
- typedef std::set<LiveSegment> LiveSegments;
-
- // A set of live virtual registers. Elements have type LiveInterval, where
- // each element represents the liveness of a single live virtual register.
- // This is traditionally known as a live range, but we refer is as a live
- // virtual register to avoid confusing it with the misnamed LiveRange
- // class.
- typedef std::vector<LiveInterval*> LiveVirtRegs;
+ // 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
// to reach the current segment's containing virtual register.
typedef LiveSegments::iterator SegmentIter;
- class InterferenceResult;
+ // LiveIntervalUnions share an external allocator.
+ typedef LiveSegments::Allocator Allocator;
+
class Query;
private:
- unsigned repReg_; // representative register number
- LiveSegments segments_; // union of virtual reg segements
- LiveVirtRegs lvrs_; // set of live virtual regs in the union
+ const unsigned RepReg; // representative register number
+ unsigned Tag; // unique tag for current contents.
+ LiveSegments Segments; // union of virtual reg segments
public:
- // default ctor avoids placement new
- LiveIntervalUnion() : repReg_(0) {}
-
- void init(unsigned repReg) { repReg_ = repReg; }
-
- SegmentIter begin() { return segments_.begin(); }
- SegmentIter end() { return segments_.end(); }
-
- /// FIXME: !!!!!!!!!!! Keeps a non-const ref
- void unify(LiveInterval &lvr);
-
- // FIXME: needed by RegAllocGreedy
- //void extract(const LiveInterval &li);
-
- /// Cache a single interference test result in the form of two intersecting
- /// segments. This allows efficiently iterating over the interferences. The
- /// iteration logic is handled by LiveIntervalUnion::Query which may
- /// filter interferences depending on the type of query.
- class InterferenceResult {
- friend class Query;
-
- LiveInterval::iterator lvrSegI_; // current position in _lvr
- SegmentIter liuSegI_; // current position in _liu
-
- // Internal ctor.
- InterferenceResult(LiveInterval::iterator lvrSegI, SegmentIter liuSegI)
- : lvrSegI_(lvrSegI), liuSegI_(liuSegI) {}
+ LiveIntervalUnion(unsigned r, Allocator &a) : RepReg(r), Tag(0), Segments(a)
+ {}
- public:
- // Public default ctor.
- InterferenceResult(): lvrSegI_(), liuSegI_() {}
+ // 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(); }
- // Note: this interface provides raw access to the iterators because the
- // result has no way to tell if it's valid to dereference them.
+ // Provide public access to the underlying map to allow overlap iteration.
+ typedef LiveSegments Map;
+ const Map &getMap() { return Segments; }
- // Access the lvr segment.
- const LiveInterval::iterator &lvrSegPos() const { return lvrSegI_; }
+ /// getTag - Return an opaque tag representing the current state of the union.
+ unsigned getTag() const { return Tag; }
- // Access the liu segment.
- const SegmentIter &liuSeg() const { return liuSegI_; }
+ /// changedSince - Return true if the union change since getTag returned tag.
+ bool changedSince(unsigned tag) const { return tag != Tag; }
- bool operator==(const InterferenceResult &ir) const {
- return lvrSegI_ == ir.lvrSegI_ && liuSegI_ == ir.liuSegI_;
- }
- bool operator!=(const InterferenceResult &ir) const {
- return !operator==(ir);
- }
- };
+ // 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 &liu_;
- LiveInterval &lvr_;
- InterferenceResult firstInterference_;
- // TBD: interfering vregs
+ 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(LiveInterval &lvr, LiveIntervalUnion &liu): liu_(liu), lvr_(lvr) {}
-
- LiveInterval &lvr() const { return lvr_; }
+ 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;
+ }
- bool isInterference(const InterferenceResult &ir) const {
- if (ir.lvrSegI_ != lvr_.end()) {
- assert(overlap(*ir.lvrSegI_, *ir.liuSegI_) &&
- "invalid segment iterators");
- return true;
+ 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;
}
- return false;
+ 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 isInterference(firstInterference()); }
+ // 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;
- // First pair of interfering segments, or a noninterfering result.
- InterferenceResult firstInterference();
+ // 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;
+ }
- // Treat the result as an iterator and advance to the next interfering pair
- // of segments. Visiting each unique interfering pairs means that the same
- // lvr or liu segment may be visited multiple times.
- bool nextInterference(InterferenceResult &ir) const;
-
- // TBD: bool collectInterferingVirtRegs(unsigned maxInterference)
+ /// checkLoopInterference - Return true if there is interference overlapping
+ /// Loop.
+ bool checkLoopInterference(MachineLoopRange*);
private:
- // Private interface for queries
- void findIntersection(InterferenceResult &ir) const;
+ Query(const Query&); // DO NOT IMPLEMENT
+ void operator=(const Query&); // DO NOT IMPLEMENT
};
};
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