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https://github.com/c64scene-ar/llvm-6502.git
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7ed47a1335
discussion of this change. Boy are my fingers tired. ;-) git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@45411 91177308-0d34-0410-b5e6-96231b3b80d8
369 lines
14 KiB
C++
369 lines
14 KiB
C++
//===-- llvm/CodeGen/LiveInterval.h - Interval representation ---*- C++ -*-===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This file implements the LiveRange and LiveInterval classes. Given some
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// numbering of each the machine instructions an interval [i, j) is said to be a
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// live interval for register v if there is no instruction with number j' > j
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// such that v is live at j' and there is no instruction with number i' < i such
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// that v is live at i'. In this implementation intervals can have holes,
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// i.e. an interval might look like [1,20), [50,65), [1000,1001). Each
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// individual range is represented as an instance of LiveRange, and the whole
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// interval is represented as an instance of LiveInterval.
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//
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_CODEGEN_LIVEINTERVAL_H
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#define LLVM_CODEGEN_LIVEINTERVAL_H
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#include "llvm/ADT/SmallVector.h"
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#include "llvm/Support/Allocator.h"
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#include "llvm/Support/Streams.h"
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#include <iosfwd>
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#include <vector>
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#include <cassert>
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namespace llvm {
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class MachineInstr;
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class MRegisterInfo;
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struct LiveInterval;
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/// VNInfo - If the value number definition is undefined (e.g. phi
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/// merge point), it contains ~0u,x. If the value number is not in use, it
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/// contains ~1u,x to indicate that the value # is not used.
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/// def - Instruction # of the definition.
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/// reg - Source reg iff val# is defined by a copy; zero otherwise.
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/// hasPHIKill - One or more of the kills are PHI nodes.
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/// kills - Instruction # of the kills. If a kill is an odd #, it means
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/// the kill is a phi join point.
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struct VNInfo {
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unsigned id;
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unsigned def;
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unsigned reg;
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bool hasPHIKill;
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SmallVector<unsigned, 4> kills;
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VNInfo() : id(~1U), def(~1U), reg(0), hasPHIKill(false) {}
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VNInfo(unsigned i, unsigned d, unsigned r)
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: id(i), def(d), reg(r), hasPHIKill(false) {}
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};
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/// LiveRange structure - This represents a simple register range in the
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/// program, with an inclusive start point and an exclusive end point.
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/// These ranges are rendered as [start,end).
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struct LiveRange {
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unsigned start; // Start point of the interval (inclusive)
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unsigned end; // End point of the interval (exclusive)
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VNInfo *valno; // identifier for the value contained in this interval.
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LiveRange(unsigned S, unsigned E, VNInfo *V) : start(S), end(E), valno(V) {
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assert(S < E && "Cannot create empty or backwards range");
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}
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/// contains - Return true if the index is covered by this range.
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///
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bool contains(unsigned I) const {
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return start <= I && I < end;
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}
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bool operator<(const LiveRange &LR) const {
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return start < LR.start || (start == LR.start && end < LR.end);
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}
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bool operator==(const LiveRange &LR) const {
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return start == LR.start && end == LR.end;
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}
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void dump() const;
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void print(std::ostream &os) const;
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void print(std::ostream *os) const { if (os) print(*os); }
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private:
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LiveRange(); // DO NOT IMPLEMENT
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};
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std::ostream& operator<<(std::ostream& os, const LiveRange &LR);
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inline bool operator<(unsigned V, const LiveRange &LR) {
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return V < LR.start;
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}
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inline bool operator<(const LiveRange &LR, unsigned V) {
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return LR.start < V;
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}
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/// LiveInterval - This class represents some number of live ranges for a
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/// register or value. This class also contains a bit of register allocator
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/// state.
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struct LiveInterval {
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typedef SmallVector<LiveRange,4> Ranges;
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typedef SmallVector<VNInfo*,4> VNInfoList;
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unsigned reg; // the register of this interval
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unsigned preference; // preferred register to allocate for this interval
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float weight; // weight of this interval
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Ranges ranges; // the ranges in which this register is live
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VNInfoList valnos; // value#'s
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public:
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LiveInterval(unsigned Reg, float Weight)
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: reg(Reg), preference(0), weight(Weight) {
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}
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typedef Ranges::iterator iterator;
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iterator begin() { return ranges.begin(); }
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iterator end() { return ranges.end(); }
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typedef Ranges::const_iterator const_iterator;
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const_iterator begin() const { return ranges.begin(); }
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const_iterator end() const { return ranges.end(); }
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typedef VNInfoList::iterator vni_iterator;
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vni_iterator vni_begin() { return valnos.begin(); }
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vni_iterator vni_end() { return valnos.end(); }
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typedef VNInfoList::const_iterator const_vni_iterator;
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const_vni_iterator vni_begin() const { return valnos.begin(); }
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const_vni_iterator vni_end() const { return valnos.end(); }
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/// advanceTo - Advance the specified iterator to point to the LiveRange
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/// containing the specified position, or end() if the position is past the
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/// end of the interval. If no LiveRange contains this position, but the
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/// position is in a hole, this method returns an iterator pointing the the
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/// LiveRange immediately after the hole.
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iterator advanceTo(iterator I, unsigned Pos) {
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if (Pos >= endNumber())
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return end();
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while (I->end <= Pos) ++I;
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return I;
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}
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bool containsOneValue() const { return valnos.size() == 1; }
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unsigned getNumValNums() const { return valnos.size(); }
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/// getValNumInfo - Returns pointer to the specified val#.
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///
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inline VNInfo *getValNumInfo(unsigned ValNo) {
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return valnos[ValNo];
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}
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inline const VNInfo *getValNumInfo(unsigned ValNo) const {
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return valnos[ValNo];
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}
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/// copyValNumInfo - Copy the value number info for one value number to
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/// another.
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void copyValNumInfo(VNInfo *DstValNo, const VNInfo *SrcValNo) {
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DstValNo->def = SrcValNo->def;
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DstValNo->reg = SrcValNo->reg;
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DstValNo->hasPHIKill = SrcValNo->hasPHIKill;
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DstValNo->kills = SrcValNo->kills;
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}
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/// getNextValue - Create a new value number and return it. MIIdx specifies
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/// the instruction that defines the value number.
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VNInfo *getNextValue(unsigned MIIdx, unsigned SrcReg,
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BumpPtrAllocator &VNInfoAllocator) {
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#ifdef __GNUC__
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unsigned Alignment = __alignof__(VNInfo);
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#else
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// FIXME: ugly.
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unsigned Alignment = 8;
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#endif
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VNInfo *VNI= static_cast<VNInfo*>(VNInfoAllocator.Allocate(sizeof(VNInfo),
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Alignment));
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new (VNI) VNInfo(valnos.size(), MIIdx, SrcReg);
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valnos.push_back(VNI);
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return VNI;
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}
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/// addKillForValNum - Add a kill instruction index to the specified value
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/// number.
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static void addKill(VNInfo *VNI, unsigned KillIdx) {
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SmallVector<unsigned, 4> &kills = VNI->kills;
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if (kills.empty()) {
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kills.push_back(KillIdx);
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} else {
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SmallVector<unsigned, 4>::iterator
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I = std::lower_bound(kills.begin(), kills.end(), KillIdx);
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kills.insert(I, KillIdx);
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}
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}
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/// addKills - Add a number of kills into the VNInfo kill vector. If this
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/// interval is live at a kill point, then the kill is not added.
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void addKills(VNInfo *VNI, const SmallVector<unsigned, 4> &kills) {
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for (unsigned i = 0, e = kills.size(); i != e; ++i) {
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unsigned KillIdx = kills[i];
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if (!liveAt(KillIdx)) {
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SmallVector<unsigned, 4>::iterator
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I = std::lower_bound(VNI->kills.begin(), VNI->kills.end(), KillIdx);
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VNI->kills.insert(I, KillIdx);
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}
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}
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}
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/// removeKill - Remove the specified kill from the list of kills of
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/// the specified val#.
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static bool removeKill(VNInfo *VNI, unsigned KillIdx) {
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SmallVector<unsigned, 4> &kills = VNI->kills;
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SmallVector<unsigned, 4>::iterator
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I = std::lower_bound(kills.begin(), kills.end(), KillIdx);
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if (I != kills.end() && *I == KillIdx) {
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kills.erase(I);
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return true;
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}
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return false;
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}
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/// removeKills - Remove all the kills in specified range
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/// [Start, End] of the specified val#.
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void removeKills(VNInfo *VNI, unsigned Start, unsigned End) {
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SmallVector<unsigned, 4> &kills = VNI->kills;
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SmallVector<unsigned, 4>::iterator
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I = std::lower_bound(kills.begin(), kills.end(), Start);
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SmallVector<unsigned, 4>::iterator
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E = std::upper_bound(kills.begin(), kills.end(), End);
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kills.erase(I, E);
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}
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/// MergeValueNumberInto - This method is called when two value nubmers
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/// are found to be equivalent. This eliminates V1, replacing all
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/// LiveRanges with the V1 value number with the V2 value number. This can
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/// cause merging of V1/V2 values numbers and compaction of the value space.
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void MergeValueNumberInto(VNInfo *V1, VNInfo *V2);
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/// MergeInClobberRanges - For any live ranges that are not defined in the
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/// current interval, but are defined in the Clobbers interval, mark them
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/// used with an unknown definition value. Caller must pass in reference to
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/// VNInfoAllocator since it will create a new val#.
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void MergeInClobberRanges(const LiveInterval &Clobbers,
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BumpPtrAllocator &VNInfoAllocator);
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/// MergeValueInAsValue - Merge all of the live ranges of a specific val#
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/// in RHS into this live interval as the specified value number.
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/// The LiveRanges in RHS are allowed to overlap with LiveRanges in the
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/// current interval, it will replace the value numbers of the overlaped
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/// live ranges with the specified value number.
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void MergeRangesInAsValue(const LiveInterval &RHS, VNInfo *LHSValNo);
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/// MergeValueInAsValue - Merge all of the live ranges of a specific val#
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/// in RHS into this live interval as the specified value number.
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/// The LiveRanges in RHS are allowed to overlap with LiveRanges in the
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/// current interval, but only if the overlapping LiveRanges have the
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/// specified value number.
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void MergeValueInAsValue(const LiveInterval &RHS,
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const VNInfo *RHSValNo, VNInfo *LHSValNo);
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/// Copy - Copy the specified live interval. This copies all the fields
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/// except for the register of the interval.
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void Copy(const LiveInterval &RHS, BumpPtrAllocator &VNInfoAllocator);
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bool empty() const { return ranges.empty(); }
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/// beginNumber - Return the lowest numbered slot covered by interval.
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unsigned beginNumber() const {
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assert(!empty() && "empty interval for register");
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return ranges.front().start;
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}
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/// endNumber - return the maximum point of the interval of the whole,
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/// exclusive.
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unsigned endNumber() const {
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assert(!empty() && "empty interval for register");
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return ranges.back().end;
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}
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bool expiredAt(unsigned index) const {
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return index >= endNumber();
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}
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bool liveAt(unsigned index) const;
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/// getLiveRangeContaining - Return the live range that contains the
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/// specified index, or null if there is none.
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const LiveRange *getLiveRangeContaining(unsigned Idx) const {
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const_iterator I = FindLiveRangeContaining(Idx);
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return I == end() ? 0 : &*I;
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}
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/// FindLiveRangeContaining - Return an iterator to the live range that
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/// contains the specified index, or end() if there is none.
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const_iterator FindLiveRangeContaining(unsigned Idx) const;
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/// FindLiveRangeContaining - Return an iterator to the live range that
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/// contains the specified index, or end() if there is none.
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iterator FindLiveRangeContaining(unsigned Idx);
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/// getOverlapingRanges - Given another live interval which is defined as a
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/// copy from this one, return a list of all of the live ranges where the
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/// two overlap and have different value numbers.
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void getOverlapingRanges(const LiveInterval &Other, unsigned CopyIdx,
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std::vector<LiveRange*> &Ranges);
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/// overlaps - Return true if the intersection of the two live intervals is
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/// not empty.
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bool overlaps(const LiveInterval& other) const {
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return overlapsFrom(other, other.begin());
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}
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/// overlapsFrom - Return true if the intersection of the two live intervals
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/// is not empty. The specified iterator is a hint that we can begin
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/// scanning the Other interval starting at I.
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bool overlapsFrom(const LiveInterval& other, const_iterator I) const;
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/// addRange - Add the specified LiveRange to this interval, merging
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/// intervals as appropriate. This returns an iterator to the inserted live
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/// range (which may have grown since it was inserted.
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void addRange(LiveRange LR) {
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addRangeFrom(LR, ranges.begin());
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}
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/// join - Join two live intervals (this, and other) together. This applies
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/// mappings to the value numbers in the LHS/RHS intervals as specified. If
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/// the intervals are not joinable, this aborts.
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void join(LiveInterval &Other, const int *ValNoAssignments,
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const int *RHSValNoAssignments,
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SmallVector<VNInfo*, 16> &NewVNInfo);
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/// removeRange - Remove the specified range from this interval. Note that
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/// the range must already be in this interval in its entirety.
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void removeRange(unsigned Start, unsigned End);
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void removeRange(LiveRange LR) {
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removeRange(LR.start, LR.end);
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}
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/// getSize - Returns the sum of sizes of all the LiveRange's.
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///
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unsigned getSize() const;
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bool operator<(const LiveInterval& other) const {
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return beginNumber() < other.beginNumber();
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}
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void print(std::ostream &OS, const MRegisterInfo *MRI = 0) const;
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void print(std::ostream *OS, const MRegisterInfo *MRI = 0) const {
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if (OS) print(*OS, MRI);
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}
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void dump() const;
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private:
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Ranges::iterator addRangeFrom(LiveRange LR, Ranges::iterator From);
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void extendIntervalEndTo(Ranges::iterator I, unsigned NewEnd);
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Ranges::iterator extendIntervalStartTo(Ranges::iterator I, unsigned NewStr);
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LiveInterval& operator=(const LiveInterval& rhs); // DO NOT IMPLEMENT
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};
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inline std::ostream &operator<<(std::ostream &OS, const LiveInterval &LI) {
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LI.print(OS);
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return OS;
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}
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}
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#endif
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