LLVM: llvm::AntiDepBreaker Class Reference

LLVM 8.0.1

This class works in conjunction with the post-RA scheduler to rename registers to break register anti-dependencies (WAR hazards). More...

#include "CodeGen/AntiDepBreaker.h"

Inheritance diagram for llvm::AntiDepBreaker:

Inheritance graph

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Public Types
using	DbgValueVector = std::vector< std::pair< MachineInstr , MachineInstr > >

Public Member Functions
virtual	~AntiDepBreaker ()

virtual void	StartBlock (MachineBasicBlock *BB)=0
	Initialize anti-dep breaking for a new basic block. More...

virtual unsigned	BreakAntiDependencies (const std::vector< SUnit > &SUnits, MachineBasicBlock::iterator Begin, MachineBasicBlock::iterator End, unsigned InsertPosIndex, DbgValueVector &DbgValues)=0
	Identifiy anti-dependencies within a basic-block region and break them by renaming registers. More...

virtual void	Observe (MachineInstr &MI, unsigned Count, unsigned InsertPosIndex)=0
	Update liveness information to account for the current instruction, which will not be scheduled. More...

virtual void	FinishBlock ()=0
	Finish anti-dep breaking for a basic block. More...

void	UpdateDbgValue (MachineInstr &MI, unsigned OldReg, unsigned NewReg)
	Update DBG_VALUE if dependency breaker is updating other machine instruction to use NewReg. More...

void	UpdateDbgValues (const DbgValueVector &DbgValues, MachineInstr *ParentMI, unsigned OldReg, unsigned NewReg)
	Update all DBG_VALUE instructions that may be affected by the dependency breaker's update of ParentMI to use NewReg. More...

Detailed Description

This class works in conjunction with the post-RA scheduler to rename registers to break register anti-dependencies (WAR hazards).

Definition at line 32 of file AntiDepBreaker.h.

Member Typedef Documentation

◆ DbgValueVector

using llvm::AntiDepBreaker::DbgValueVector = std::vector<std::pair<MachineInstr *, MachineInstr *> >

Definition at line 35 of file AntiDepBreaker.h.

Constructor & Destructor Documentation

◆ ~AntiDepBreaker()

AntiDepBreaker::~AntiDepBreaker ( )

virtual

Definition at line 77 of file PostRASchedulerList.cpp.

References llvm::AnalysisUsage::addPreserved(), llvm::AnalysisUsage::addRequired(), llvm::sys::path::begin(), llvm::sys::path::end(), llvm::MachineFunctionPass::getAnalysisUsage(), MI, Mode, llvm::MachineFunctionProperties::NoVRegs, Observe(), llvm::MachineFunctionProperties::set(), llvm::AnalysisUsage::setPreservesCFG(), llvm::ARM_MB::ST, and TII.

Member Function Documentation

◆ BreakAntiDependencies()

virtual unsigned llvm::AntiDepBreaker::BreakAntiDependencies	(	const std::vector< SUnit > &	SUnits,
		MachineBasicBlock::iterator	Begin,
		MachineBasicBlock::iterator	End,
		unsigned	InsertPosIndex,
		DbgValueVector &	DbgValues
	)

pure virtual

Identifiy anti-dependencies within a basic-block region and break them by renaming registers.

Return the number of anti-dependencies broken.

Implemented in llvm::AggressiveAntiDepBreaker, and llvm::CriticalAntiDepBreaker.

◆ FinishBlock()

virtual void llvm::AntiDepBreaker::FinishBlock ( )

pure virtual

Finish anti-dep breaking for a basic block.

Implemented in llvm::AggressiveAntiDepBreaker, and llvm::CriticalAntiDepBreaker.

◆ Observe()

virtual void llvm::AntiDepBreaker::Observe	(	MachineInstr &	MI,
		unsigned	Count,
		unsigned	InsertPosIndex
	)

pure virtual

Update liveness information to account for the current instruction, which will not be scheduled.

Implemented in llvm::AggressiveAntiDepBreaker, and llvm::CriticalAntiDepBreaker.

Referenced by ~AntiDepBreaker().

◆ StartBlock()

virtual void llvm::AntiDepBreaker::StartBlock ( MachineBasicBlock * BB )

pure virtual

Initialize anti-dep breaking for a new basic block.

Implemented in llvm::AggressiveAntiDepBreaker, and llvm::CriticalAntiDepBreaker.

◆ UpdateDbgValue()

void llvm::AntiDepBreaker::UpdateDbgValue	(	MachineInstr &	MI,
		unsigned	OldReg,
		unsigned	NewReg
	)

inline

Update DBG_VALUE if dependency breaker is updating other machine instruction to use NewReg.

Definition at line 60 of file AntiDepBreaker.h.

References assert(), llvm::MachineInstr::getOperand(), llvm::MachineOperand::getReg(), llvm::MachineInstr::isDebugValue(), llvm::MachineOperand::isReg(), and llvm::MachineOperand::setReg().

◆ UpdateDbgValues()

void llvm::AntiDepBreaker::UpdateDbgValues	(	const DbgValueVector &	DbgValues,
		MachineInstr *	ParentMI,
		unsigned	OldReg,
		unsigned	NewReg
	)

inline

Update all DBG_VALUE instructions that may be affected by the dependency breaker's update of ParentMI to use NewReg.

Definition at line 68 of file AntiDepBreaker.h.

References llvm::make_range().

The documentation for this class was generated from the following files:

lib/CodeGen/AntiDepBreaker.h
lib/CodeGen/PostRASchedulerList.cpp