104 lines
3.9 KiB
C
104 lines
3.9 KiB
C
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//=- llvm/CodeGen/CriticalAntiDepBreaker.h - Anti-Dep Support -*- 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 CriticalAntiDepBreaker class, which
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// implements register anti-dependence breaking along a blocks
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// critical path during post-RA scheduler.
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//
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_CODEGEN_CRITICALANTIDEPBREAKER_H
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#define LLVM_CODEGEN_CRITICALANTIDEPBREAKER_H
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#include "AntiDepBreaker.h"
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#include "llvm/CodeGen/MachineBasicBlock.h"
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#include "llvm/CodeGen/MachineFrameInfo.h"
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#include "llvm/CodeGen/MachineFunction.h"
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#include "llvm/CodeGen/MachineRegisterInfo.h"
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#include "llvm/CodeGen/ScheduleDAG.h"
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#include "llvm/Target/TargetRegisterInfo.h"
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#include "llvm/ADT/BitVector.h"
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#include "llvm/ADT/SmallSet.h"
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namespace llvm {
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class CriticalAntiDepBreaker : public AntiDepBreaker {
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MachineFunction& MF;
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MachineRegisterInfo &MRI;
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const TargetRegisterInfo *TRI;
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/// AllocatableSet - The set of allocatable registers.
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/// We'll be ignoring anti-dependencies on non-allocatable registers,
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/// because they may not be safe to break.
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const BitVector AllocatableSet;
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/// Classes - For live regs that are only used in one register class in a
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/// live range, the register class. If the register is not live, the
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/// corresponding value is null. If the register is live but used in
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/// multiple register classes, the corresponding value is -1 casted to a
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/// pointer.
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const TargetRegisterClass *
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Classes[TargetRegisterInfo::FirstVirtualRegister];
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/// RegRegs - Map registers to all their references within a live range.
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std::multimap<unsigned, MachineOperand *> RegRefs;
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/// KillIndices - The index of the most recent kill (proceding bottom-up),
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/// or ~0u if the register is not live.
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unsigned KillIndices[TargetRegisterInfo::FirstVirtualRegister];
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/// DefIndices - The index of the most recent complete def (proceding bottom
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/// up), or ~0u if the register is live.
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unsigned DefIndices[TargetRegisterInfo::FirstVirtualRegister];
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/// KeepRegs - A set of registers which are live and cannot be changed to
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/// break anti-dependencies.
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SmallSet<unsigned, 4> KeepRegs;
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public:
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CriticalAntiDepBreaker(MachineFunction& MFi);
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~CriticalAntiDepBreaker();
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/// GetMaxTrials - Critical path anti-dependence breaking requires
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/// only a single pass
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unsigned GetMaxTrials() { return 1; }
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/// NeedCandidates - Candidates not needed.
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bool NeedCandidates() { return false; }
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/// Start - Initialize anti-dep breaking for a new basic block.
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void StartBlock(MachineBasicBlock *BB);
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/// BreakAntiDependencies - Identifiy anti-dependencies along the critical path
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/// of the ScheduleDAG and break them by renaming registers.
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///
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unsigned BreakAntiDependencies(std::vector<SUnit>& SUnits,
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CandidateMap& Candidates,
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MachineBasicBlock::iterator& Begin,
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MachineBasicBlock::iterator& End,
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unsigned InsertPosIndex);
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/// Observe - Update liveness information to account for the current
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/// instruction, which will not be scheduled.
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///
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void Observe(MachineInstr *MI, unsigned Count, unsigned InsertPosIndex);
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/// Finish - Finish anti-dep breaking for a basic block.
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void FinishBlock();
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private:
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void PrescanInstruction(MachineInstr *MI);
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void ScanInstruction(MachineInstr *MI, unsigned Count);
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unsigned findSuitableFreeRegister(unsigned AntiDepReg,
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unsigned LastNewReg,
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const TargetRegisterClass *);
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};
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}
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#endif
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