// This file implements the LiveRange and LiveInterval classes. Given some
// numbering of each the machine instructions an interval [i, j) is said to be a
// live interval for register v if there is no instruction with number j' > j
-// such that v is live at j' abd there is no instruction with number i' < i such
+// such that v is live at j' and there is no instruction with number i' < i such
// that v is live at i'. In this implementation intervals can have holes,
// i.e. an interval might look like [1,20), [50,65), [1000,1001). Each
// individual range is represented as an instance of LiveRange, and the whole
#ifndef LLVM_CODEGEN_LIVEINTERVAL_H
#define LLVM_CODEGEN_LIVEINTERVAL_H
+#include "llvm/ADT/SmallVector.h"
+#include "llvm/Support/Allocator.h"
+#include "llvm/Support/Streams.h"
#include <iosfwd>
#include <vector>
#include <cassert>
namespace llvm {
+ class MachineInstr;
+ class MRegisterInfo;
+ struct LiveInterval;
+
+ /// VNInfo - If the value number definition is undefined (e.g. phi
+ /// merge point), it contains ~0u,x. If the value number is not in use, it
+ /// contains ~1u,x to indicate that the value # is not used.
+ /// def - Instruction # of the definition.
+ /// reg - Source reg iff val# is defined by a copy; zero otherwise.
+ /// kills - Instruction # of the kills. If a kill is an odd #, it means
+ /// the kill is a phi join point.
+ struct VNInfo {
+ unsigned id;
+ unsigned def;
+ unsigned reg;
+ SmallVector<unsigned, 4> kills;
+ VNInfo() : id(~1U), def(~1U), reg(0) {}
+ VNInfo(unsigned i, unsigned d, unsigned r)
+ : id(i), def(d), reg(r) {}
+ };
+
/// LiveRange structure - This represents a simple register range in the
/// program, with an inclusive start point and an exclusive end point.
/// These ranges are rendered as [start,end).
struct LiveRange {
unsigned start; // Start point of the interval (inclusive)
- unsigned end; // End point of the interval (exclusive)
- LiveRange(unsigned S, unsigned E) : start(S), end(E) {
+ unsigned end; // End point of the interval (exclusive)
+ VNInfo *valno; // identifier for the value contained in this interval.
+
+ LiveRange(unsigned S, unsigned E, VNInfo *V) : start(S), end(E), valno(V) {
assert(S < E && "Cannot create empty or backwards range");
}
+ /// contains - Return true if the index is covered by this range.
+ ///
+ bool contains(unsigned I) const {
+ return start <= I && I < end;
+ }
+
bool operator<(const LiveRange &LR) const {
return start < LR.start || (start == LR.start && end < LR.end);
}
bool operator==(const LiveRange &LR) const {
return start == LR.start && end == LR.end;
}
- private:
+
+ void dump() const;
+ void print(std::ostream &os) const;
+ void print(std::ostream *os) const { if (os) print(*os); }
+
+ private:
LiveRange(); // DO NOT IMPLEMENT
};
+
std::ostream& operator<<(std::ostream& os, const LiveRange &LR);
+
inline bool operator<(unsigned V, const LiveRange &LR) {
return V < LR.start;
}
+ inline bool operator<(const LiveRange &LR, unsigned V) {
+ return LR.start < V;
+ }
/// LiveInterval - This class represents some number of live ranges for a
/// register or value. This class also contains a bit of register allocator
/// state.
struct LiveInterval {
- typedef std::vector<LiveRange> Ranges;
+ typedef SmallVector<LiveRange,4> Ranges;
+ typedef SmallVector<VNInfo*,4> VNInfoList;
+
unsigned reg; // the register of this interval
+ unsigned preference; // preferred register to allocate for this interval
float weight; // weight of this interval
Ranges ranges; // the ranges in which this register is live
- bool isDefinedOnce; // True if this interval contains one value.
+ VNInfoList valnos; // value#'s
+ public:
LiveInterval(unsigned Reg, float Weight)
- : reg(Reg), weight(Weight), isDefinedOnce(false) {
+ : reg(Reg), preference(0), weight(Weight) {
}
- bool containsOneValue() const { return isDefinedOnce; }
+ typedef Ranges::iterator iterator;
+ iterator begin() { return ranges.begin(); }
+ iterator end() { return ranges.end(); }
+ typedef Ranges::const_iterator const_iterator;
+ const_iterator begin() const { return ranges.begin(); }
+ const_iterator end() const { return ranges.end(); }
+
+ typedef VNInfoList::iterator vni_iterator;
+ vni_iterator vni_begin() { return valnos.begin(); }
+ vni_iterator vni_end() { return valnos.end(); }
+
+ typedef VNInfoList::const_iterator const_vni_iterator;
+ const_vni_iterator vni_begin() const { return valnos.begin(); }
+ const_vni_iterator vni_end() const { return valnos.end(); }
+
+ /// advanceTo - Advance the specified iterator to point to the LiveRange
+ /// containing the specified position, or end() if the position is past the
+ /// end of the interval. If no LiveRange contains this position, but the
+ /// position is in a hole, this method returns an iterator pointing the the
+ /// LiveRange immediately after the hole.
+ iterator advanceTo(iterator I, unsigned Pos) {
+ if (Pos >= endNumber())
+ return end();
+ while (I->end <= Pos) ++I;
+ return I;
+ }
+
+ bool containsOneValue() const { return valnos.size() == 1; }
+
+ unsigned getNumValNums() const { return valnos.size(); }
+
+ /// getValNumInfo - Returns pointer to the specified val#.
+ ///
+ inline VNInfo *getValNumInfo(unsigned ValNo) {
+ return valnos[ValNo];
+ }
+ inline const VNInfo *getValNumInfo(unsigned ValNo) const {
+ return valnos[ValNo];
+ }
+
+ /// copyValNumInfo - Copy the value number info for one value number to
+ /// another.
+ void copyValNumInfo(VNInfo *DstValNo, const VNInfo *SrcValNo) {
+ DstValNo->def = SrcValNo->def;
+ DstValNo->reg = SrcValNo->reg;
+ DstValNo->kills = SrcValNo->kills;
+ }
+
+ /// getNextValue - Create a new value number and return it. MIIdx specifies
+ /// the instruction that defines the value number.
+ VNInfo *getNextValue(unsigned MIIdx, unsigned SrcReg,
+ BumpPtrAllocator &VNInfoAllocator) {
+#ifdef __GNUC__
+ unsigned Alignment = __alignof__(VNInfo);
+#else
+ // FIXME: ugly.
+ unsigned Alignment = 8;
+#endif
+ VNInfo *VNI= static_cast<VNInfo*>(VNInfoAllocator.Allocate(sizeof(VNInfo),
+ Alignment));
+ new (VNI) VNInfo(valnos.size(), MIIdx, SrcReg);
+ valnos.push_back(VNI);
+ return VNI;
+ }
+
+ /// addKillForValNum - Add a kill instruction index to the specified value
+ /// number.
+ static void addKill(VNInfo *VNI, unsigned KillIdx) {
+ SmallVector<unsigned, 4> &kills = VNI->kills;
+ if (kills.empty()) {
+ kills.push_back(KillIdx);
+ } else {
+ SmallVector<unsigned, 4>::iterator
+ I = std::lower_bound(kills.begin(), kills.end(), KillIdx);
+ kills.insert(I, KillIdx);
+ }
+ }
+
+ /// addKills - Add a number of kills into the VNInfo kill vector. If this
+ /// interval is live at a kill point, then the kill is not added.
+ void addKills(VNInfo *VNI, const SmallVector<unsigned, 4> &kills) {
+ for (unsigned i = 0, e = kills.size(); i != e; ++i) {
+ unsigned KillIdx = kills[i];
+ if (!liveAt(KillIdx)) {
+ SmallVector<unsigned, 4>::iterator
+ I = std::lower_bound(VNI->kills.begin(), VNI->kills.end(), KillIdx);
+ VNI->kills.insert(I, KillIdx);
+ }
+ }
+ }
+
+ /// removeKill - Remove the specified kill from the list of kills of
+ /// the specified val#.
+ static bool removeKill(VNInfo *VNI, unsigned KillIdx) {
+ SmallVector<unsigned, 4> &kills = VNI->kills;
+ SmallVector<unsigned, 4>::iterator
+ I = std::lower_bound(kills.begin(), kills.end(), KillIdx);
+ if (I != kills.end() && *I == KillIdx) {
+ kills.erase(I);
+ return true;
+ }
+ return false;
+ }
+
+ /// removeKills - Remove all the kills in specified range
+ /// [Start, End] of the specified val#.
+ void removeKills(VNInfo *VNI, unsigned Start, unsigned End) {
+ SmallVector<unsigned, 4> &kills = VNI->kills;
+ SmallVector<unsigned, 4>::iterator
+ I = std::lower_bound(kills.begin(), kills.end(), Start);
+ SmallVector<unsigned, 4>::iterator
+ E = std::upper_bound(kills.begin(), kills.end(), End);
+ kills.erase(I, E);
+ }
+
+ /// MergeValueNumberInto - This method is called when two value nubmers
+ /// are found to be equivalent. This eliminates V1, replacing all
+ /// LiveRanges with the V1 value number with the V2 value number. This can
+ /// cause merging of V1/V2 values numbers and compaction of the value space.
+ void MergeValueNumberInto(VNInfo *V1, VNInfo *V2);
+
+ /// MergeInClobberRanges - For any live ranges that are not defined in the
+ /// current interval, but are defined in the Clobbers interval, mark them
+ /// used with an unknown definition value. Caller must pass in reference to
+ /// VNInfoAllocator since it will create a new val#.
+ void MergeInClobberRanges(const LiveInterval &Clobbers,
+ BumpPtrAllocator &VNInfoAllocator);
+
+ /// MergeRangesInAsValue - Merge all of the live ranges in RHS into this
+ /// live interval as the specified value number. The LiveRanges in RHS are
+ /// allowed to overlap with LiveRanges in the current interval, but only if
+ /// the overlapping LiveRanges have the specified value number.
+ void MergeRangesInAsValue(const LiveInterval &RHS, VNInfo *LHSValNo);
+
+ /// MergeValueInAsValue - Merge all of the live ranges of a specific val#
+ /// in RHS into this live interval as the specified value number.
+ /// The LiveRanges in RHS are allowed to overlap with LiveRanges in the
+ /// current interval, but only if the overlapping LiveRanges have the
+ /// specified value number.
+ void MergeValueInAsValue(const LiveInterval &RHS,
+ VNInfo *RHSValNo, VNInfo *LHSValNo);
+
+ /// Copy - Copy the specified live interval. This copies all the fields
+ /// except for the register of the interval.
+ void Copy(const LiveInterval &RHS, BumpPtrAllocator &VNInfoAllocator);
+
bool empty() const { return ranges.empty(); }
- /// start - Return the lowest numbered slot covered by interval.
- unsigned start() const {
+ /// beginNumber - Return the lowest numbered slot covered by interval.
+ unsigned beginNumber() const {
assert(!empty() && "empty interval for register");
return ranges.front().start;
}
- /// end - return the maximum point of the interval of the whole,
+ /// endNumber - return the maximum point of the interval of the whole,
/// exclusive.
- unsigned end() const {
+ unsigned endNumber() const {
assert(!empty() && "empty interval for register");
return ranges.back().end;
}
bool expiredAt(unsigned index) const {
- return end() <= (index + 1);
+ return index >= endNumber();
}
bool liveAt(unsigned index) const;
- bool overlaps(const LiveInterval& other) const;
+ /// getLiveRangeContaining - Return the live range that contains the
+ /// specified index, or null if there is none.
+ const LiveRange *getLiveRangeContaining(unsigned Idx) const {
+ const_iterator I = FindLiveRangeContaining(Idx);
+ return I == end() ? 0 : &*I;
+ }
+
+ /// FindLiveRangeContaining - Return an iterator to the live range that
+ /// contains the specified index, or end() if there is none.
+ const_iterator FindLiveRangeContaining(unsigned Idx) const;
+
+ /// FindLiveRangeContaining - Return an iterator to the live range that
+ /// contains the specified index, or end() if there is none.
+ iterator FindLiveRangeContaining(unsigned Idx);
+
+ /// getOverlapingRanges - Given another live interval which is defined as a
+ /// copy from this one, return a list of all of the live ranges where the
+ /// two overlap and have different value numbers.
+ void getOverlapingRanges(const LiveInterval &Other, unsigned CopyIdx,
+ std::vector<LiveRange*> &Ranges);
+
+ /// overlaps - Return true if the intersection of the two live intervals is
+ /// not empty.
+ bool overlaps(const LiveInterval& other) const {
+ return overlapsFrom(other, other.begin());
+ }
+
+ /// overlapsFrom - Return true if the intersection of the two live intervals
+ /// is not empty. The specified iterator is a hint that we can begin
+ /// scanning the Other interval starting at I.
+ bool overlapsFrom(const LiveInterval& other, const_iterator I) const;
- void addRange(LiveRange R);
+ /// addRange - Add the specified LiveRange to this interval, merging
+ /// intervals as appropriate. This returns an iterator to the inserted live
+ /// range (which may have grown since it was inserted.
+ void addRange(LiveRange LR) {
+ addRangeFrom(LR, ranges.begin());
+ }
+
+ /// join - Join two live intervals (this, and other) together. This applies
+ /// mappings to the value numbers in the LHS/RHS intervals as specified. If
+ /// the intervals are not joinable, this aborts.
+ void join(LiveInterval &Other, const int *ValNoAssignments,
+ const int *RHSValNoAssignments,
+ SmallVector<VNInfo*, 16> &NewVNInfo);
+
+ /// removeRange - Remove the specified range from this interval. Note that
+ /// the range must already be in this interval in its entirety.
+ void removeRange(unsigned Start, unsigned End);
- void join(const LiveInterval& other);
+ void removeRange(LiveRange LR) {
+ removeRange(LR.start, LR.end);
+ }
+
+ /// getSize - Returns the sum of sizes of all the LiveRange's.
+ ///
+ unsigned getSize() const;
bool operator<(const LiveInterval& other) const {
- return start() < other.start();
+ return beginNumber() < other.beginNumber();
}
- bool operator==(const LiveInterval& other) const {
- return reg == other.reg;
+ void print(std::ostream &OS, const MRegisterInfo *MRI = 0) const;
+ void print(std::ostream *OS, const MRegisterInfo *MRI = 0) const {
+ if (OS) print(*OS, MRI);
}
+ void dump() const;
private:
- Ranges::iterator mergeRangesForward(Ranges::iterator it);
- Ranges::iterator mergeRangesBackward(Ranges::iterator it);
+ Ranges::iterator addRangeFrom(LiveRange LR, Ranges::iterator From);
+ void extendIntervalEndTo(Ranges::iterator I, unsigned NewEnd);
+ Ranges::iterator extendIntervalStartTo(Ranges::iterator I, unsigned NewStr);
+ LiveInterval& operator=(const LiveInterval& rhs); // DO NOT IMPLEMENT
};
- std::ostream& operator<<(std::ostream& os, const LiveInterval& li);
+ inline std::ostream &operator<<(std::ostream &OS, const LiveInterval &LI) {
+ LI.print(OS);
+ return OS;
+ }
}
#endif