#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.
-///
-/// Note: This currently represents a half-open interval [start,end).
-/// If LiveRange is modified to represent a closed interval, so should this.
-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);
- }
-
- // Order segments by starting point only--we expect them to be disjoint.
- bool operator<(const LiveSegment &ls) const { return start < ls.start; }
-};
-
-inline bool operator<(SlotIndex V, const LiveSegment &ls) {
- return V < ls.start;
-}
+class MachineLoopRange;
+class TargetRegisterInfo;
-inline bool operator<(const LiveSegment &ls, SlotIndex V) {
- return ls.start < V;
-}
+#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 &lvrSeg, const LiveSegment &liuSeg) {
- return lvrSeg.start < liuSeg.end && liuSeg.start < lvrSeg.end;
+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
+ unsigned Tag; // unique tag for current contents.
+ LiveSegments Segments; // union of virtual reg segments
public:
- // default ctor avoids placement new
- LiveIntervalUnion() : repReg_(0) {}
-
- // Initialize the union by associating it with a representative register
- // number.
- void init(unsigned repReg) { repReg_ = repReg; }
+ 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 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(); }
- // Return an iterator to the first segment after or including begin that
- // intersects with lvrSeg.
- SegmentIter upperBound(SegmentIter begin, const LiveSegment &seg);
+ // Provide public access to the underlying map to allow overlap iteration.
+ typedef LiveSegments Map;
+ const Map &getMap() { return Segments; }
- // Add a live virtual register to this union and merge its segments.
- // Holds a nonconst reference to the LVR for later maniplution.
- void unify(LiveInterval &lvr);
+ /// getTag - Return an opaque tag representing the current state of the union.
+ unsigned getTag() const { return Tag; }
- // Remove a live virtual register's segments from this union.
- void extract(const LiveInterval &lvr);
-
- /// 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) {}
+ /// changedSince - Return true if the union change since getTag returned tag.
+ bool changedSince(unsigned tag) const { return tag != Tag; }
- public:
- // Public default ctor.
- InterferenceResult(): lvrSegI_(), liuSegI_() {}
+ // Add a live virtual register to this union and merge its segments.
+ void unify(LiveInterval &VirtReg);
- // Note: this interface provides raw access to the iterators because the
- // result has no way to tell if it's valid to dereference them.
+ // Remove a live virtual register's segments from this union.
+ void extract(LiveInterval &VirtReg);
- // Access the lvr segment.
- const LiveInterval::iterator &lvrSegPos() const { return lvrSegI_; }
+ // Remove all inserted virtual registers.
+ void clear() { Segments.clear(); ++Tag; }
- // Access the liu segment.
- const SegmentIter &liuSegPos() const { return liuSegI_; }
+ // Print union, using TRI to translate register names
+ void print(raw_ostream &OS, const TargetRegisterInfo *TRI) const;
- bool operator==(const InterferenceResult &ir) const {
- return lvrSegI_ == ir.lvrSegI_ && liuSegI_ == ir.liuSegI_;
- }
- bool operator!=(const InterferenceResult &ir) const {
- return !operator==(ir);
- }
- };
+#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(): liu_(), lvr_() {}
+ Query(): LiveUnion(), VirtReg(), Tag(0), UserTag(0) {}
- Query(LiveInterval *lvr, LiveIntervalUnion *liu): liu_(liu), lvr_(lvr) {}
+ Query(LiveInterval *VReg, LiveIntervalUnion *LIU):
+ LiveUnion(LIU), VirtReg(VReg), CheckedFirstInterference(false),
+ SeenAllInterferences(false), SeenUnspillableVReg(false)
+ {}
void clear() {
- liu_ = NULL;
- lvr_ = NULL;
- firstInterference_ = InterferenceResult();
+ LiveUnion = NULL;
+ VirtReg = NULL;
+ InterferingVRegs.clear();
+ CheckedFirstInterference = false;
+ SeenAllInterferences = false;
+ SeenUnspillableVReg = false;
+ Tag = 0;
+ UserTag = 0;
}
-
- void init(LiveInterval *lvr, LiveIntervalUnion *liu) {
- if (lvr_ == lvr) {
- // We currently allow query objects to be reused acrossed live virtual
- // registers, but always for the same live interval union.
- assert(liu_ == liu && "inconsistent initialization");
+
+ 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;
}
- liu_ = liu;
- lvr_ = lvr;
- // Clear cached results.
- firstInterference_ = InterferenceResult();
+ clear();
+ LiveUnion = LIU;
+ VirtReg = VReg;
+ Tag = LIU->getTag();
+ UserTag = UTag;
}
- LiveInterval &lvr() const { assert(lvr_ && "uninitialized"); return *lvr_; }
-
- bool isInterference(const InterferenceResult &ir) const {
- if (ir.lvrSegI_ != lvr_->end()) {
- assert(overlap(*ir.lvrSegI_, *ir.liuSegI_) &&
- "invalid segment iterators");
- return true;
- }
- return false;
+ 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;
- // Get the first pair of interfering segments, or a noninterfering result.
- // This initializes the firstInterference_ cache.
- InterferenceResult firstInterference();
+ // Did collectInterferingVRegs collect all interferences?
+ bool seenAllInterferences() const { return SeenAllInterferences; }
- // 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)
+ // 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:
- // Private interface for queries
- void findIntersection(InterferenceResult &ir) const;
+ Query(const Query&) LLVM_DELETED_FUNCTION;
+ void operator=(const Query&) LLVM_DELETED_FUNCTION;
+ };
+
+ // 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];
+ }
};
};
projects / oota-llvm.git / blobdiff