forked from OSchip/llvm-project
114 lines
4.2 KiB
C++
114 lines
4.2 KiB
C++
//===- 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_LIB_CODEGEN_CRITICALANTIDEPBREAKER_H
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#define LLVM_LIB_CODEGEN_CRITICALANTIDEPBREAKER_H
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#include "AntiDepBreaker.h"
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#include "llvm/ADT/BitVector.h"
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#include "llvm/Support/Compiler.h"
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#include <map>
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#include <vector>
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namespace llvm {
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class MachineBasicBlock;
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class MachineFunction;
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class MachineInstr;
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class MachineOperand;
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class MachineRegisterInfo;
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class RegisterClassInfo;
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class TargetInstrInfo;
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class TargetRegisterClass;
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class TargetRegisterInfo;
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class LLVM_LIBRARY_VISIBILITY CriticalAntiDepBreaker : public AntiDepBreaker {
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MachineFunction& MF;
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MachineRegisterInfo &MRI;
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const TargetInstrInfo *TII;
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const TargetRegisterInfo *TRI;
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const RegisterClassInfo &RegClassInfo;
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/// 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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/// 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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std::vector<const TargetRegisterClass *> Classes;
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/// Map registers to all their references within a live range.
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std::multimap<unsigned, MachineOperand *> RegRefs;
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using RegRefIter =
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std::multimap<unsigned, MachineOperand *>::const_iterator;
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/// The index of the most recent kill (proceeding bottom-up),
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/// or ~0u if the register is not live.
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std::vector<unsigned> KillIndices;
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/// The index of the most recent complete def (proceeding
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/// bottom up), or ~0u if the register is live.
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std::vector<unsigned> DefIndices;
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/// A set of registers which are live and cannot be changed to
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/// break anti-dependencies.
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BitVector KeepRegs;
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public:
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CriticalAntiDepBreaker(MachineFunction& MFi, const RegisterClassInfo &RCI);
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~CriticalAntiDepBreaker() override;
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/// Initialize anti-dep breaking for a new basic block.
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void StartBlock(MachineBasicBlock *BB) override;
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/// Identifiy anti-dependencies along the critical path
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/// of the ScheduleDAG and break them by renaming registers.
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unsigned BreakAntiDependencies(const std::vector<SUnit> &SUnits,
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MachineBasicBlock::iterator Begin,
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MachineBasicBlock::iterator End,
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unsigned InsertPosIndex,
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DbgValueVector &DbgValues) override;
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/// Update liveness information to account for the current
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/// instruction, which will not be scheduled.
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void Observe(MachineInstr &MI, unsigned Count,
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unsigned InsertPosIndex) override;
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/// Finish anti-dep breaking for a basic block.
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void FinishBlock() override;
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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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bool isNewRegClobberedByRefs(RegRefIter RegRefBegin,
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RegRefIter RegRefEnd,
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unsigned NewReg);
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unsigned findSuitableFreeRegister(RegRefIter RegRefBegin,
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RegRefIter RegRefEnd,
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unsigned AntiDepReg,
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unsigned LastNewReg,
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const TargetRegisterClass *RC,
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SmallVectorImpl<unsigned> &Forbid);
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};
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} // end namespace llvm
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#endif // LLVM_LIB_CODEGEN_CRITICALANTIDEPBREAKER_H
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