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//===- llvm/CodeGen/VirtRegMap.h - Virtual Register Map ---------*- C++ -*-===//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
// This file implements a virtual register map. This maps virtual registers to
// physical registers and virtual registers to stack slots. It is created and
// updated by a register allocator and then used by a machine code rewriter that
// adds spill code and rewrites virtual into physical register references.
#include "llvm/ADT/IndexedMap.h"
#include "llvm/CodeGen/MachineFunctionPass.h"
#include "llvm/CodeGen/TargetRegisterInfo.h"
#include "llvm/CodeGen/TileShapeInfo.h"
#include "llvm/Pass.h"
#include <cassert>
namespace llvm {
class MachineFunction;
class MachineRegisterInfo;
class raw_ostream;
class TargetInstrInfo;
class VirtRegMap : public MachineFunctionPass {
enum {
NO_STACK_SLOT = (1L << 30)-1,
MAX_STACK_SLOT = (1L << 18)-1
MachineRegisterInfo *MRI = nullptr;
const TargetInstrInfo *TII = nullptr;
const TargetRegisterInfo *TRI = nullptr;
MachineFunction *MF = nullptr;
/// Virt2PhysMap - This is a virtual to physical register
/// mapping. Each virtual register is required to have an entry in
/// it; even spilled virtual registers (the register mapped to a
/// spilled register is the temporary used to load it from the
/// stack).
IndexedMap<Register, VirtReg2IndexFunctor> Virt2PhysMap;
/// Virt2StackSlotMap - This is virtual register to stack slot
/// mapping. Each spilled virtual register has an entry in it
/// which corresponds to the stack slot this register is spilled
/// at.
IndexedMap<int, VirtReg2IndexFunctor> Virt2StackSlotMap;
/// Virt2SplitMap - This is virtual register to splitted virtual register
/// mapping.
IndexedMap<unsigned, VirtReg2IndexFunctor> Virt2SplitMap;
/// Virt2ShapeMap - For X86 AMX register whose register is bound shape
/// information.
DenseMap<unsigned, ShapeT> Virt2ShapeMap;
/// createSpillSlot - Allocate a spill slot for RC from MFI.
unsigned createSpillSlot(const TargetRegisterClass *RC);
static char ID;
: MachineFunctionPass(ID), Virt2PhysMap(NO_PHYS_REG),
Virt2StackSlotMap(NO_STACK_SLOT), Virt2SplitMap(0) {}
VirtRegMap(const VirtRegMap &) = delete;
VirtRegMap &operator=(const VirtRegMap &) = delete;
bool runOnMachineFunction(MachineFunction &MF) override;
void getAnalysisUsage(AnalysisUsage &AU) const override {
MachineFunction &getMachineFunction() const {
assert(MF && "getMachineFunction called before runOnMachineFunction");
return *MF;
MachineRegisterInfo &getRegInfo() const { return *MRI; }
const TargetRegisterInfo &getTargetRegInfo() const { return *TRI; }
void grow();
/// returns true if the specified virtual register is
/// mapped to a physical register
bool hasPhys(Register virtReg) const {
return getPhys(virtReg) != NO_PHYS_REG;
/// returns the physical register mapped to the specified
/// virtual register
MCRegister getPhys(Register virtReg) const {
return MCRegister::from(Virt2PhysMap[]);
/// creates a mapping for the specified virtual register to
/// the specified physical register
void assignVirt2Phys(Register virtReg, MCPhysReg physReg);
bool isShapeMapEmpty() const { return Virt2ShapeMap.empty(); }
bool hasShape(Register virtReg) const {
return getShape(virtReg).isValid();
ShapeT getShape(Register virtReg) const {
return Virt2ShapeMap.lookup(virtReg);
void assignVirt2Shape(Register virtReg, ShapeT shape) {
Virt2ShapeMap[] = shape;
/// clears the specified virtual register's, physical
/// register mapping
void clearVirt(Register virtReg) {
assert(Virt2PhysMap[] != NO_PHYS_REG &&
"attempt to clear a not assigned virtual register");
Virt2PhysMap[] = NO_PHYS_REG;
/// clears all virtual to physical register mappings
void clearAllVirt() {
/// returns true if VirtReg is assigned to its preferred physreg.
bool hasPreferredPhys(Register VirtReg) const;
/// returns true if VirtReg has a known preferred register.
/// This returns false if VirtReg has a preference that is a virtual
/// register that hasn't been assigned yet.
bool hasKnownPreference(Register VirtReg) const;
/// records virtReg is a split live interval from SReg.
void setIsSplitFromReg(Register virtReg, Register SReg) {
Virt2SplitMap[] = SReg;
if (hasShape(SReg)) {
Virt2ShapeMap[] = getShape(SReg);
/// returns the live interval virtReg is split from.
Register getPreSplitReg(Register virtReg) const {
return Virt2SplitMap[];
/// getOriginal - Return the original virtual register that VirtReg descends
/// from through splitting.
/// A register that was not created by splitting is its own original.
/// This operation is idempotent.
Register getOriginal(Register VirtReg) const {
Register Orig = getPreSplitReg(VirtReg);
return Orig ? Orig : VirtReg;
/// returns true if the specified virtual register is not
/// mapped to a stack slot or rematerialized.
bool isAssignedReg(Register virtReg) const {
if (getStackSlot(virtReg) == NO_STACK_SLOT)
return true;
// Split register can be assigned a physical register as well as a
// stack slot or remat id.
return (Virt2SplitMap[] &&
Virt2PhysMap[] != NO_PHYS_REG);
/// returns the stack slot mapped to the specified virtual
/// register
int getStackSlot(Register virtReg) const {
return Virt2StackSlotMap[];
/// create a mapping for the specifed virtual register to
/// the next available stack slot
int assignVirt2StackSlot(Register virtReg);
/// create a mapping for the specified virtual register to
/// the specified stack slot
void assignVirt2StackSlot(Register virtReg, int SS);
void print(raw_ostream &OS, const Module* M = nullptr) const override;
void dump() const;
inline raw_ostream &operator<<(raw_ostream &OS, const VirtRegMap &VRM) {
return OS;
} // end llvm namespace