| //==- ScheduleDAGInstrs.h - MachineInstr Scheduling --------------*- C++ -*-==// |
| // |
| // The LLVM Compiler Infrastructure |
| // |
| // This file is distributed under the University of Illinois Open Source |
| // License. See LICENSE.TXT for details. |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // This file implements the ScheduleDAGInstrs class, which implements |
| // scheduling for a MachineInstr-based dependency graph. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #ifndef LLVM_CODEGEN_SCHEDULEDAGINSTRS_H |
| #define LLVM_CODEGEN_SCHEDULEDAGINSTRS_H |
| |
| #include "llvm/ADT/SparseMultiSet.h" |
| #include "llvm/ADT/SparseSet.h" |
| #include "llvm/CodeGen/ScheduleDAG.h" |
| #include "llvm/CodeGen/TargetSchedule.h" |
| #include "llvm/Support/Compiler.h" |
| #include "llvm/Target/TargetRegisterInfo.h" |
| |
| namespace llvm { |
| class MachineFrameInfo; |
| class MachineLoopInfo; |
| class MachineDominatorTree; |
| class LiveIntervals; |
| class RegPressureTracker; |
| class PressureDiffs; |
| |
| /// An individual mapping from virtual register number to SUnit. |
| struct VReg2SUnit { |
| unsigned VirtReg; |
| SUnit *SU; |
| |
| VReg2SUnit(unsigned reg, SUnit *su): VirtReg(reg), SU(su) {} |
| |
| unsigned getSparseSetIndex() const { |
| return TargetRegisterInfo::virtReg2Index(VirtReg); |
| } |
| }; |
| |
| /// Record a physical register access. |
| /// For non-data-dependent uses, OpIdx == -1. |
| struct PhysRegSUOper { |
| SUnit *SU; |
| int OpIdx; |
| unsigned Reg; |
| |
| PhysRegSUOper(SUnit *su, int op, unsigned R): SU(su), OpIdx(op), Reg(R) {} |
| |
| unsigned getSparseSetIndex() const { return Reg; } |
| }; |
| |
| /// Use a SparseMultiSet to track physical registers. Storage is only |
| /// allocated once for the pass. It can be cleared in constant time and reused |
| /// without any frees. |
| typedef SparseMultiSet<PhysRegSUOper, llvm::identity<unsigned>, uint16_t> |
| Reg2SUnitsMap; |
| |
| /// Use SparseSet as a SparseMap by relying on the fact that it never |
| /// compares ValueT's, only unsigned keys. This allows the set to be cleared |
| /// between scheduling regions in constant time as long as ValueT does not |
| /// require a destructor. |
| typedef SparseSet<VReg2SUnit, VirtReg2IndexFunctor> VReg2SUnitMap; |
| |
| /// Track local uses of virtual registers. These uses are gathered by the DAG |
| /// builder and may be consulted by the scheduler to avoid iterating an entire |
| /// vreg use list. |
| typedef SparseMultiSet<VReg2SUnit, VirtReg2IndexFunctor> VReg2UseMap; |
| |
| /// ScheduleDAGInstrs - A ScheduleDAG subclass for scheduling lists of |
| /// MachineInstrs. |
| class ScheduleDAGInstrs : public ScheduleDAG { |
| protected: |
| const MachineLoopInfo &MLI; |
| const MachineDominatorTree &MDT; |
| const MachineFrameInfo *MFI; |
| |
| /// Live Intervals provides reaching defs in preRA scheduling. |
| LiveIntervals *LIS; |
| |
| /// TargetSchedModel provides an interface to the machine model. |
| TargetSchedModel SchedModel; |
| |
| /// isPostRA flag indicates vregs cannot be present. |
| bool IsPostRA; |
| |
| /// True if the DAG builder should remove kill flags (in preparation for |
| /// rescheduling). |
| bool RemoveKillFlags; |
| |
| /// The standard DAG builder does not normally include terminators as DAG |
| /// nodes because it does not create the necessary dependencies to prevent |
| /// reordering. A specialized scheduler can override |
| /// TargetInstrInfo::isSchedulingBoundary then enable this flag to indicate |
| /// it has taken responsibility for scheduling the terminator correctly. |
| bool CanHandleTerminators; |
| |
| /// State specific to the current scheduling region. |
| /// ------------------------------------------------ |
| |
| /// The block in which to insert instructions |
| MachineBasicBlock *BB; |
| |
| /// The beginning of the range to be scheduled. |
| MachineBasicBlock::iterator RegionBegin; |
| |
| /// The end of the range to be scheduled. |
| MachineBasicBlock::iterator RegionEnd; |
| |
| /// Instructions in this region (distance(RegionBegin, RegionEnd)). |
| unsigned NumRegionInstrs; |
| |
| /// After calling BuildSchedGraph, each machine instruction in the current |
| /// scheduling region is mapped to an SUnit. |
| DenseMap<MachineInstr*, SUnit*> MISUnitMap; |
| |
| /// After calling BuildSchedGraph, each vreg used in the scheduling region |
| /// is mapped to a set of SUnits. These include all local vreg uses, not |
| /// just the uses for a singly defined vreg. |
| VReg2UseMap VRegUses; |
| |
| /// State internal to DAG building. |
| /// ------------------------------- |
| |
| /// Defs, Uses - Remember where defs and uses of each register are as we |
| /// iterate upward through the instructions. This is allocated here instead |
| /// of inside BuildSchedGraph to avoid the need for it to be initialized and |
| /// destructed for each block. |
| Reg2SUnitsMap Defs; |
| Reg2SUnitsMap Uses; |
| |
| /// Track the last instruction in this region defining each virtual register. |
| VReg2SUnitMap VRegDefs; |
| |
| /// PendingLoads - Remember where unknown loads are after the most recent |
| /// unknown store, as we iterate. As with Defs and Uses, this is here |
| /// to minimize construction/destruction. |
| std::vector<SUnit *> PendingLoads; |
| |
| /// DbgValues - Remember instruction that precedes DBG_VALUE. |
| /// These are generated by buildSchedGraph but persist so they can be |
| /// referenced when emitting the final schedule. |
| typedef std::vector<std::pair<MachineInstr *, MachineInstr *> > |
| DbgValueVector; |
| DbgValueVector DbgValues; |
| MachineInstr *FirstDbgValue; |
| |
| /// Set of live physical registers for updating kill flags. |
| BitVector LiveRegs; |
| |
| public: |
| explicit ScheduleDAGInstrs(MachineFunction &mf, |
| const MachineLoopInfo &mli, |
| const MachineDominatorTree &mdt, |
| bool IsPostRAFlag, |
| bool RemoveKillFlags = false, |
| LiveIntervals *LIS = nullptr); |
| |
| virtual ~ScheduleDAGInstrs() {} |
| |
| bool isPostRA() const { return IsPostRA; } |
| |
| /// \brief Expose LiveIntervals for use in DAG mutators and such. |
| LiveIntervals *getLIS() const { return LIS; } |
| |
| /// \brief Get the machine model for instruction scheduling. |
| const TargetSchedModel *getSchedModel() const { return &SchedModel; } |
| |
| /// \brief Resolve and cache a resolved scheduling class for an SUnit. |
| const MCSchedClassDesc *getSchedClass(SUnit *SU) const { |
| if (!SU->SchedClass && SchedModel.hasInstrSchedModel()) |
| SU->SchedClass = SchedModel.resolveSchedClass(SU->getInstr()); |
| return SU->SchedClass; |
| } |
| |
| /// begin - Return an iterator to the top of the current scheduling region. |
| MachineBasicBlock::iterator begin() const { return RegionBegin; } |
| |
| /// end - Return an iterator to the bottom of the current scheduling region. |
| MachineBasicBlock::iterator end() const { return RegionEnd; } |
| |
| /// newSUnit - Creates a new SUnit and return a ptr to it. |
| SUnit *newSUnit(MachineInstr *MI); |
| |
| /// getSUnit - Return an existing SUnit for this MI, or NULL. |
| SUnit *getSUnit(MachineInstr *MI) const; |
| |
| /// startBlock - Prepare to perform scheduling in the given block. |
| virtual void startBlock(MachineBasicBlock *BB); |
| |
| /// finishBlock - Clean up after scheduling in the given block. |
| virtual void finishBlock(); |
| |
| /// Initialize the scheduler state for the next scheduling region. |
| virtual void enterRegion(MachineBasicBlock *bb, |
| MachineBasicBlock::iterator begin, |
| MachineBasicBlock::iterator end, |
| unsigned regioninstrs); |
| |
| /// Notify that the scheduler has finished scheduling the current region. |
| virtual void exitRegion(); |
| |
| /// buildSchedGraph - Build SUnits from the MachineBasicBlock that we are |
| /// input. |
| void buildSchedGraph(AliasAnalysis *AA, |
| RegPressureTracker *RPTracker = nullptr, |
| PressureDiffs *PDiffs = nullptr); |
| |
| /// addSchedBarrierDeps - Add dependencies from instructions in the current |
| /// list of instructions being scheduled to scheduling barrier. We want to |
| /// make sure instructions which define registers that are either used by |
| /// the terminator or are live-out are properly scheduled. This is |
| /// especially important when the definition latency of the return value(s) |
| /// are too high to be hidden by the branch or when the liveout registers |
| /// used by instructions in the fallthrough block. |
| void addSchedBarrierDeps(); |
| |
| /// schedule - Order nodes according to selected style, filling |
| /// in the Sequence member. |
| /// |
| /// Typically, a scheduling algorithm will implement schedule() without |
| /// overriding enterRegion() or exitRegion(). |
| virtual void schedule() = 0; |
| |
| /// finalizeSchedule - Allow targets to perform final scheduling actions at |
| /// the level of the whole MachineFunction. By default does nothing. |
| virtual void finalizeSchedule() {} |
| |
| void dumpNode(const SUnit *SU) const override; |
| |
| /// Return a label for a DAG node that points to an instruction. |
| std::string getGraphNodeLabel(const SUnit *SU) const override; |
| |
| /// Return a label for the region of code covered by the DAG. |
| std::string getDAGName() const override; |
| |
| /// \brief Fix register kill flags that scheduling has made invalid. |
| void fixupKills(MachineBasicBlock *MBB); |
| protected: |
| void initSUnits(); |
| void addPhysRegDataDeps(SUnit *SU, unsigned OperIdx); |
| void addPhysRegDeps(SUnit *SU, unsigned OperIdx); |
| void addVRegDefDeps(SUnit *SU, unsigned OperIdx); |
| void addVRegUseDeps(SUnit *SU, unsigned OperIdx); |
| |
| /// \brief PostRA helper for rewriting kill flags. |
| void startBlockForKills(MachineBasicBlock *BB); |
| |
| /// \brief Toggle a register operand kill flag. |
| /// |
| /// Other adjustments may be made to the instruction if necessary. Return |
| /// true if the operand has been deleted, false if not. |
| bool toggleKillFlag(MachineInstr *MI, MachineOperand &MO); |
| }; |
| |
| /// newSUnit - Creates a new SUnit and return a ptr to it. |
| inline SUnit *ScheduleDAGInstrs::newSUnit(MachineInstr *MI) { |
| #ifndef NDEBUG |
| const SUnit *Addr = SUnits.empty() ? nullptr : &SUnits[0]; |
| #endif |
| SUnits.push_back(SUnit(MI, (unsigned)SUnits.size())); |
| assert((Addr == nullptr || Addr == &SUnits[0]) && |
| "SUnits std::vector reallocated on the fly!"); |
| SUnits.back().OrigNode = &SUnits.back(); |
| return &SUnits.back(); |
| } |
| |
| /// getSUnit - Return an existing SUnit for this MI, or NULL. |
| inline SUnit *ScheduleDAGInstrs::getSUnit(MachineInstr *MI) const { |
| DenseMap<MachineInstr*, SUnit*>::const_iterator I = MISUnitMap.find(MI); |
| if (I == MISUnitMap.end()) |
| return nullptr; |
| return I->second; |
| } |
| } // namespace llvm |
| |
| #endif |