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//===- llvm/CodeGen/MachineRegisterInfo.h -----------------------*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file defines the MachineRegisterInfo class.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_CODEGEN_MACHINEREGISTERINFO_H
#define LLVM_CODEGEN_MACHINEREGISTERINFO_H
#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/BitVector.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/IndexedMap.h"
#include "llvm/ADT/PointerUnion.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/StringSet.h"
#include "llvm/ADT/iterator_range.h"
#include "llvm/CodeGen/GlobalISel/RegisterBank.h"
#include "llvm/CodeGen/LowLevelType.h"
#include "llvm/CodeGen/MachineBasicBlock.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineInstrBundle.h"
#include "llvm/CodeGen/MachineOperand.h"
#include "llvm/CodeGen/TargetRegisterInfo.h"
#include "llvm/CodeGen/TargetSubtargetInfo.h"
#include "llvm/MC/LaneBitmask.h"
#include <cassert>
#include <cstddef>
#include <cstdint>
#include <iterator>
#include <memory>
#include <utility>
#include <vector>
namespace llvm {
class PSetIterator;
/// Convenient type to represent either a register class or a register bank.
using RegClassOrRegBank =
PointerUnion<const TargetRegisterClass *, const RegisterBank *>;
/// MachineRegisterInfo - Keep track of information for virtual and physical
/// registers, including vreg register classes, use/def chains for registers,
/// etc.
class MachineRegisterInfo {
public:
class Delegate {
virtual void anchor();
public:
virtual ~Delegate() = default;
virtual void MRI_NoteNewVirtualRegister(unsigned Reg) = 0;
};
private:
MachineFunction *MF;
Delegate *TheDelegate = nullptr;
/// True if subregister liveness is tracked.
const bool TracksSubRegLiveness;
/// VRegInfo - Information we keep for each virtual register.
///
/// Each element in this list contains the register class of the vreg and the
/// start of the use/def list for the register.
IndexedMap<std::pair<RegClassOrRegBank, MachineOperand *>,
VirtReg2IndexFunctor>
VRegInfo;
/// Map for recovering vreg name from vreg number.
/// This map is used by the MIR Printer.
IndexedMap<std::string, VirtReg2IndexFunctor> VReg2Name;
/// StringSet that is used to unique vreg names.
StringSet<> VRegNames;
/// The flag is true upon \p UpdatedCSRs initialization
/// and false otherwise.
bool IsUpdatedCSRsInitialized;
/// Contains the updated callee saved register list.
/// As opposed to the static list defined in register info,
/// all registers that were disabled are removed from the list.
SmallVector<MCPhysReg, 16> UpdatedCSRs;
/// RegAllocHints - This vector records register allocation hints for
/// virtual registers. For each virtual register, it keeps a pair of hint
/// type and hints vector making up the allocation hints. Only the first
/// hint may be target specific, and in that case this is reflected by the
/// first member of the pair being non-zero. If the hinted register is
/// virtual, it means the allocator should prefer the physical register
/// allocated to it if any.
IndexedMap<std::pair<unsigned, SmallVector<unsigned, 4>>,
VirtReg2IndexFunctor> RegAllocHints;
/// PhysRegUseDefLists - This is an array of the head of the use/def list for
/// physical registers.
std::unique_ptr<MachineOperand *[]> PhysRegUseDefLists;
/// getRegUseDefListHead - Return the head pointer for the register use/def
/// list for the specified virtual or physical register.
MachineOperand *&getRegUseDefListHead(unsigned RegNo) {
if (TargetRegisterInfo::isVirtualRegister(RegNo))
return VRegInfo[RegNo].second;
return PhysRegUseDefLists[RegNo];
}
MachineOperand *getRegUseDefListHead(unsigned RegNo) const {
if (TargetRegisterInfo::isVirtualRegister(RegNo))
return VRegInfo[RegNo].second;
return PhysRegUseDefLists[RegNo];
}
/// Get the next element in the use-def chain.
static MachineOperand *getNextOperandForReg(const MachineOperand *MO) {
assert(MO && MO->isReg() && "This is not a register operand!");
return MO->Contents.Reg.Next;
}
/// UsedPhysRegMask - Additional used physregs including aliases.
/// This bit vector represents all the registers clobbered by function calls.
BitVector UsedPhysRegMask;
/// ReservedRegs - This is a bit vector of reserved registers. The target
/// may change its mind about which registers should be reserved. This
/// vector is the frozen set of reserved registers when register allocation
/// started.
BitVector ReservedRegs;
using VRegToTypeMap = IndexedMap<LLT, VirtReg2IndexFunctor>;
/// Map generic virtual registers to their low-level type.
VRegToTypeMap VRegToType;
/// Keep track of the physical registers that are live in to the function.
/// Live in values are typically arguments in registers. LiveIn values are
/// allowed to have virtual registers associated with them, stored in the
/// second element.
std::vector<std::pair<unsigned, unsigned>> LiveIns;
public:
explicit MachineRegisterInfo(MachineFunction *MF);
MachineRegisterInfo(const MachineRegisterInfo &) = delete;
MachineRegisterInfo &operator=(const MachineRegisterInfo &) = delete;
const TargetRegisterInfo *getTargetRegisterInfo() const {
return MF->getSubtarget().getRegisterInfo();
}
void resetDelegate(Delegate *delegate) {
// Ensure another delegate does not take over unless the current
// delegate first unattaches itself. If we ever need to multicast
// notifications, we will need to change to using a list.
assert(TheDelegate == delegate &&
"Only the current delegate can perform reset!");
TheDelegate = nullptr;
}
void setDelegate(Delegate *delegate) {
assert(delegate && !TheDelegate &&
"Attempted to set delegate to null, or to change it without "
"first resetting it!");
TheDelegate = delegate;
}
//===--------------------------------------------------------------------===//
// Function State
//===--------------------------------------------------------------------===//
// isSSA - Returns true when the machine function is in SSA form. Early
// passes require the machine function to be in SSA form where every virtual
// register has a single defining instruction.
//
// The TwoAddressInstructionPass and PHIElimination passes take the machine
// function out of SSA form when they introduce multiple defs per virtual
// register.
bool isSSA() const {
return MF->getProperties().hasProperty(
MachineFunctionProperties::Property::IsSSA);
}
// leaveSSA - Indicates that the machine function is no longer in SSA form.
void leaveSSA() {
MF->getProperties().reset(MachineFunctionProperties::Property::IsSSA);
}
/// tracksLiveness - Returns true when tracking register liveness accurately.
/// (see MachineFUnctionProperties::Property description for details)
bool tracksLiveness() const {
return MF->getProperties().hasProperty(
MachineFunctionProperties::Property::TracksLiveness);
}
/// invalidateLiveness - Indicates that register liveness is no longer being
/// tracked accurately.
///
/// This should be called by late passes that invalidate the liveness
/// information.
void invalidateLiveness() {
MF->getProperties().reset(
MachineFunctionProperties::Property::TracksLiveness);
}
/// Returns true if liveness for register class @p RC should be tracked at
/// the subregister level.
bool shouldTrackSubRegLiveness(const TargetRegisterClass &RC) const {
return subRegLivenessEnabled() && RC.HasDisjunctSubRegs;
}
bool shouldTrackSubRegLiveness(unsigned VReg) const {
assert(TargetRegisterInfo::isVirtualRegister(VReg) && "Must pass a VReg");
return shouldTrackSubRegLiveness(*getRegClass(VReg));
}
bool subRegLivenessEnabled() const {
return TracksSubRegLiveness;
}
//===--------------------------------------------------------------------===//
// Register Info
//===--------------------------------------------------------------------===//
/// Returns true if the updated CSR list was initialized and false otherwise.
bool isUpdatedCSRsInitialized() const { return IsUpdatedCSRsInitialized; }
/// Disables the register from the list of CSRs.
/// I.e. the register will not appear as part of the CSR mask.
/// \see UpdatedCalleeSavedRegs.
void disableCalleeSavedRegister(unsigned Reg);
/// Returns list of callee saved registers.
/// The function returns the updated CSR list (after taking into account
/// registers that are disabled from the CSR list).
const MCPhysReg *getCalleeSavedRegs() const;
/// Sets the updated Callee Saved Registers list.
/// Notice that it will override ant previously disabled/saved CSRs.
void setCalleeSavedRegs(ArrayRef<MCPhysReg> CSRs);
// Strictly for use by MachineInstr.cpp.
void addRegOperandToUseList(MachineOperand *MO);
// Strictly for use by MachineInstr.cpp.
void removeRegOperandFromUseList(MachineOperand *MO);
// Strictly for use by MachineInstr.cpp.
void moveOperands(MachineOperand *Dst, MachineOperand *Src, unsigned NumOps);
/// Verify the sanity of the use list for Reg.
void verifyUseList(unsigned Reg) const;
/// Verify the use list of all registers.
void verifyUseLists() const;
/// reg_begin/reg_end - Provide iteration support to walk over all definitions
/// and uses of a register within the MachineFunction that corresponds to this
/// MachineRegisterInfo object.
template<bool Uses, bool Defs, bool SkipDebug,
bool ByOperand, bool ByInstr, bool ByBundle>
class defusechain_iterator;
template<bool Uses, bool Defs, bool SkipDebug,
bool ByOperand, bool ByInstr, bool ByBundle>
class defusechain_instr_iterator;
// Make it a friend so it can access getNextOperandForReg().
template<bool, bool, bool, bool, bool, bool>
friend class defusechain_iterator;
template<bool, bool, bool, bool, bool, bool>
friend class defusechain_instr_iterator;
/// reg_iterator/reg_begin/reg_end - Walk all defs and uses of the specified
/// register.
using reg_iterator =
defusechain_iterator<true, true, false, true, false, false>;
reg_iterator reg_begin(unsigned RegNo) const {
return reg_iterator(getRegUseDefListHead(RegNo));
}
static reg_iterator reg_end() { return reg_iterator(nullptr); }
inline iterator_range<reg_iterator> reg_operands(unsigned Reg) const {
return make_range(reg_begin(Reg), reg_end());
}
/// reg_instr_iterator/reg_instr_begin/reg_instr_end - Walk all defs and uses
/// of the specified register, stepping by MachineInstr.
using reg_instr_iterator =
defusechain_instr_iterator<true, true, false, false, true, false>;
reg_instr_iterator reg_instr_begin(unsigned RegNo) const {
return reg_instr_iterator(getRegUseDefListHead(RegNo));
}
static reg_instr_iterator reg_instr_end() {
return reg_instr_iterator(nullptr);
}
inline iterator_range<reg_instr_iterator>
reg_instructions(unsigned Reg) const {
return make_range(reg_instr_begin(Reg), reg_instr_end());
}
/// reg_bundle_iterator/reg_bundle_begin/reg_bundle_end - Walk all defs and uses
/// of the specified register, stepping by bundle.
using reg_bundle_iterator =
defusechain_instr_iterator<true, true, false, false, false, true>;
reg_bundle_iterator reg_bundle_begin(unsigned RegNo) const {
return reg_bundle_iterator(getRegUseDefListHead(RegNo));
}
static reg_bundle_iterator reg_bundle_end() {
return reg_bundle_iterator(nullptr);
}
inline iterator_range<reg_bundle_iterator> reg_bundles(unsigned Reg) const {
return make_range(reg_bundle_begin(Reg), reg_bundle_end());
}
/// reg_empty - Return true if there are no instructions using or defining the
/// specified register (it may be live-in).
bool reg_empty(unsigned RegNo) const { return reg_begin(RegNo) == reg_end(); }
/// reg_nodbg_iterator/reg_nodbg_begin/reg_nodbg_end - Walk all defs and uses
/// of the specified register, skipping those marked as Debug.
using reg_nodbg_iterator =
defusechain_iterator<true, true, true, true, false, false>;
reg_nodbg_iterator reg_nodbg_begin(unsigned RegNo) const {
return reg_nodbg_iterator(getRegUseDefListHead(RegNo));
}
static reg_nodbg_iterator reg_nodbg_end() {
return reg_nodbg_iterator(nullptr);
}
inline iterator_range<reg_nodbg_iterator>
reg_nodbg_operands(unsigned Reg) const {
return make_range(reg_nodbg_begin(Reg), reg_nodbg_end());
}
/// reg_instr_nodbg_iterator/reg_instr_nodbg_begin/reg_instr_nodbg_end - Walk
/// all defs and uses of the specified register, stepping by MachineInstr,
/// skipping those marked as Debug.
using reg_instr_nodbg_iterator =
defusechain_instr_iterator<true, true, true, false, true, false>;
reg_instr_nodbg_iterator reg_instr_nodbg_begin(unsigned RegNo) const {
return reg_instr_nodbg_iterator(getRegUseDefListHead(RegNo));
}
static reg_instr_nodbg_iterator reg_instr_nodbg_end() {
return reg_instr_nodbg_iterator(nullptr);
}
inline iterator_range<reg_instr_nodbg_iterator>
reg_nodbg_instructions(unsigned Reg) const {
return make_range(reg_instr_nodbg_begin(Reg), reg_instr_nodbg_end());
}
/// reg_bundle_nodbg_iterator/reg_bundle_nodbg_begin/reg_bundle_nodbg_end - Walk
/// all defs and uses of the specified register, stepping by bundle,
/// skipping those marked as Debug.
using reg_bundle_nodbg_iterator =
defusechain_instr_iterator<true, true, true, false, false, true>;
reg_bundle_nodbg_iterator reg_bundle_nodbg_begin(unsigned RegNo) const {
return reg_bundle_nodbg_iterator(getRegUseDefListHead(RegNo));
}
static reg_bundle_nodbg_iterator reg_bundle_nodbg_end() {
return reg_bundle_nodbg_iterator(nullptr);
}
inline iterator_range<reg_bundle_nodbg_iterator>
reg_nodbg_bundles(unsigned Reg) const {
return make_range(reg_bundle_nodbg_begin(Reg), reg_bundle_nodbg_end());
}
/// reg_nodbg_empty - Return true if the only instructions using or defining
/// Reg are Debug instructions.
bool reg_nodbg_empty(unsigned RegNo) const {
return reg_nodbg_begin(RegNo) == reg_nodbg_end();
}
/// def_iterator/def_begin/def_end - Walk all defs of the specified register.
using def_iterator =
defusechain_iterator<false, true, false, true, false, false>;
def_iterator def_begin(unsigned RegNo) const {
return def_iterator(getRegUseDefListHead(RegNo));
}
static def_iterator def_end() { return def_iterator(nullptr); }
inline iterator_range<def_iterator> def_operands(unsigned Reg) const {
return make_range(def_begin(Reg), def_end());
}
/// def_instr_iterator/def_instr_begin/def_instr_end - Walk all defs of the
/// specified register, stepping by MachineInst.
using def_instr_iterator =
defusechain_instr_iterator<false, true, false, false, true, false>;
def_instr_iterator def_instr_begin(unsigned RegNo) const {
return def_instr_iterator(getRegUseDefListHead(RegNo));
}
static def_instr_iterator def_instr_end() {
return def_instr_iterator(nullptr);
}
inline iterator_range<def_instr_iterator>
def_instructions(unsigned Reg) const {
return make_range(def_instr_begin(Reg), def_instr_end());
}
/// def_bundle_iterator/def_bundle_begin/def_bundle_end - Walk all defs of the
/// specified register, stepping by bundle.
using def_bundle_iterator =
defusechain_instr_iterator<false, true, false, false, false, true>;
def_bundle_iterator def_bundle_begin(unsigned RegNo) const {
return def_bundle_iterator(getRegUseDefListHead(RegNo));
}
static def_bundle_iterator def_bundle_end() {
return def_bundle_iterator(nullptr);
}
inline iterator_range<def_bundle_iterator> def_bundles(unsigned Reg) const {
return make_range(def_bundle_begin(Reg), def_bundle_end());
}
/// def_empty - Return true if there are no instructions defining the
/// specified register (it may be live-in).
bool def_empty(unsigned RegNo) const { return def_begin(RegNo) == def_end(); }
StringRef getVRegName(unsigned Reg) const {
return VReg2Name.inBounds(Reg) ? StringRef(VReg2Name[Reg]) : "";
}
void insertVRegByName(StringRef Name, unsigned Reg) {
assert((Name.empty() || VRegNames.find(Name) == VRegNames.end()) &&
"Named VRegs Must be Unique.");
if (!Name.empty()) {
VRegNames.insert(Name);
VReg2Name.grow(Reg);
VReg2Name[Reg] = Name.str();
}
}
/// Return true if there is exactly one operand defining the specified
/// register.
bool hasOneDef(unsigned RegNo) const {
def_iterator DI = def_begin(RegNo);
if (DI == def_end())
return false;
return ++DI == def_end();
}
/// use_iterator/use_begin/use_end - Walk all uses of the specified register.
using use_iterator =
defusechain_iterator<true, false, false, true, false, false>;
use_iterator use_begin(unsigned RegNo) const {
return use_iterator(getRegUseDefListHead(RegNo));
}
static use_iterator use_end() { return use_iterator(nullptr); }
inline iterator_range<use_iterator> use_operands(unsigned Reg) const {
return make_range(use_begin(Reg), use_end());
}
/// use_instr_iterator/use_instr_begin/use_instr_end - Walk all uses of the
/// specified register, stepping by MachineInstr.
using use_instr_iterator =
defusechain_instr_iterator<true, false, false, false, true, false>;
use_instr_iterator use_instr_begin(unsigned RegNo) const {
return use_instr_iterator(getRegUseDefListHead(RegNo));
}
static use_instr_iterator use_instr_end() {
return use_instr_iterator(nullptr);
}
inline iterator_range<use_instr_iterator>
use_instructions(unsigned Reg) const {
return make_range(use_instr_begin(Reg), use_instr_end());
}
/// use_bundle_iterator/use_bundle_begin/use_bundle_end - Walk all uses of the
/// specified register, stepping by bundle.
using use_bundle_iterator =
defusechain_instr_iterator<true, false, false, false, false, true>;
use_bundle_iterator use_bundle_begin(unsigned RegNo) const {
return use_bundle_iterator(getRegUseDefListHead(RegNo));
}
static use_bundle_iterator use_bundle_end() {
return use_bundle_iterator(nullptr);
}
inline iterator_range<use_bundle_iterator> use_bundles(unsigned Reg) const {
return make_range(use_bundle_begin(Reg), use_bundle_end());
}
/// use_empty - Return true if there are no instructions using the specified
/// register.
bool use_empty(unsigned RegNo) const { return use_begin(RegNo) == use_end(); }
/// hasOneUse - Return true if there is exactly one instruction using the
/// specified register.
bool hasOneUse(unsigned RegNo) const {
use_iterator UI = use_begin(RegNo);
if (UI == use_end())
return false;
return ++UI == use_end();
}
/// use_nodbg_iterator/use_nodbg_begin/use_nodbg_end - Walk all uses of the
/// specified register, skipping those marked as Debug.
using use_nodbg_iterator =
defusechain_iterator<true, false, true, true, false, false>;
use_nodbg_iterator use_nodbg_begin(unsigned RegNo) const {
return use_nodbg_iterator(getRegUseDefListHead(RegNo));
}
static use_nodbg_iterator use_nodbg_end() {
return use_nodbg_iterator(nullptr);
}
inline iterator_range<use_nodbg_iterator>
use_nodbg_operands(unsigned Reg) const {
return make_range(use_nodbg_begin(Reg), use_nodbg_end());
}
/// use_instr_nodbg_iterator/use_instr_nodbg_begin/use_instr_nodbg_end - Walk
/// all uses of the specified register, stepping by MachineInstr, skipping
/// those marked as Debug.
using use_instr_nodbg_iterator =
defusechain_instr_iterator<true, false, true, false, true, false>;
use_instr_nodbg_iterator use_instr_nodbg_begin(unsigned RegNo) const {
return use_instr_nodbg_iterator(getRegUseDefListHead(RegNo));
}
static use_instr_nodbg_iterator use_instr_nodbg_end() {
return use_instr_nodbg_iterator(nullptr);
}
inline iterator_range<use_instr_nodbg_iterator>
use_nodbg_instructions(unsigned Reg) const {
return make_range(use_instr_nodbg_begin(Reg), use_instr_nodbg_end());
}
/// use_bundle_nodbg_iterator/use_bundle_nodbg_begin/use_bundle_nodbg_end - Walk
/// all uses of the specified register, stepping by bundle, skipping
/// those marked as Debug.
using use_bundle_nodbg_iterator =
defusechain_instr_iterator<true, false, true, false, false, true>;
use_bundle_nodbg_iterator use_bundle_nodbg_begin(unsigned RegNo) const {
return use_bundle_nodbg_iterator(getRegUseDefListHead(RegNo));
}
static use_bundle_nodbg_iterator use_bundle_nodbg_end() {
return use_bundle_nodbg_iterator(nullptr);
}
inline iterator_range<use_bundle_nodbg_iterator>
use_nodbg_bundles(unsigned Reg) const {
return make_range(use_bundle_nodbg_begin(Reg), use_bundle_nodbg_end());
}
/// use_nodbg_empty - Return true if there are no non-Debug instructions
/// using the specified register.
bool use_nodbg_empty(unsigned RegNo) const {
return use_nodbg_begin(RegNo) == use_nodbg_end();
}
/// hasOneNonDBGUse - Return true if there is exactly one non-Debug
/// instruction using the specified register.
bool hasOneNonDBGUse(unsigned RegNo) const;
/// replaceRegWith - Replace all instances of FromReg with ToReg in the
/// machine function. This is like llvm-level X->replaceAllUsesWith(Y),
/// except that it also changes any definitions of the register as well.
///
/// Note that it is usually necessary to first constrain ToReg's register
/// class and register bank to match the FromReg constraints using one of the
/// methods:
///
/// constrainRegClass(ToReg, getRegClass(FromReg))
/// constrainRegAttrs(ToReg, FromReg)
/// RegisterBankInfo::constrainGenericRegister(ToReg,
/// *MRI.getRegClass(FromReg), MRI)
///
/// These functions will return a falsy result if the virtual registers have
/// incompatible constraints.
///
/// Note that if ToReg is a physical register the function will replace and
/// apply sub registers to ToReg in order to obtain a final/proper physical
/// register.
void replaceRegWith(unsigned FromReg, unsigned ToReg);
/// getVRegDef - Return the machine instr that defines the specified virtual
/// register or null if none is found. This assumes that the code is in SSA
/// form, so there should only be one definition.
MachineInstr *getVRegDef(unsigned Reg) const;
/// getUniqueVRegDef - Return the unique machine instr that defines the
/// specified virtual register or null if none is found. If there are
/// multiple definitions or no definition, return null.
MachineInstr *getUniqueVRegDef(unsigned Reg) const;
/// clearKillFlags - Iterate over all the uses of the given register and
/// clear the kill flag from the MachineOperand. This function is used by
/// optimization passes which extend register lifetimes and need only
/// preserve conservative kill flag information.
void clearKillFlags(unsigned Reg) const;
void dumpUses(unsigned RegNo) const;
/// Returns true if PhysReg is unallocatable and constant throughout the
/// function. Writing to a constant register has no effect.
bool isConstantPhysReg(unsigned PhysReg) const;
/// Returns true if either isConstantPhysReg or TRI->isCallerPreservedPhysReg
/// returns true. This is a utility member function.
bool isCallerPreservedOrConstPhysReg(unsigned PhysReg) const;
/// Get an iterator over the pressure sets affected by the given physical or
/// virtual register. If RegUnit is physical, it must be a register unit (from
/// MCRegUnitIterator).
PSetIterator getPressureSets(unsigned RegUnit) const;
//===--------------------------------------------------------------------===//
// Virtual Register Info
//===--------------------------------------------------------------------===//
/// Return the register class of the specified virtual register.
/// This shouldn't be used directly unless \p Reg has a register class.
/// \see getRegClassOrNull when this might happen.
const TargetRegisterClass *getRegClass(unsigned Reg) const {
assert(VRegInfo[Reg].first.is<const TargetRegisterClass *>() &&
"Register class not set, wrong accessor");
return VRegInfo[Reg].first.get<const TargetRegisterClass *>();
}
/// Return the register class of \p Reg, or null if Reg has not been assigned
/// a register class yet.
///
/// \note A null register class can only happen when these two
/// conditions are met:
/// 1. Generic virtual registers are created.
/// 2. The machine function has not completely been through the
/// instruction selection process.
/// None of this condition is possible without GlobalISel for now.
/// In other words, if GlobalISel is not used or if the query happens after
/// the select pass, using getRegClass is safe.
const TargetRegisterClass *getRegClassOrNull(unsigned Reg) const {
const RegClassOrRegBank &Val = VRegInfo[Reg].first;
return Val.dyn_cast<const TargetRegisterClass *>();
}
/// Return the register bank of \p Reg, or null if Reg has not been assigned
/// a register bank or has been assigned a register class.
/// \note It is possible to get the register bank from the register class via
/// RegisterBankInfo::getRegBankFromRegClass.
const RegisterBank *getRegBankOrNull(unsigned Reg) const {
const RegClassOrRegBank &Val = VRegInfo[Reg].first;
return Val.dyn_cast<const RegisterBank *>();
}
/// Return the register bank or register class of \p Reg.
/// \note Before the register bank gets assigned (i.e., before the
/// RegBankSelect pass) \p Reg may not have either.
const RegClassOrRegBank &getRegClassOrRegBank(unsigned Reg) const {
return VRegInfo[Reg].first;
}
/// setRegClass - Set the register class of the specified virtual register.
void setRegClass(unsigned Reg, const TargetRegisterClass *RC);
/// Set the register bank to \p RegBank for \p Reg.
void setRegBank(unsigned Reg, const RegisterBank &RegBank);
void setRegClassOrRegBank(unsigned Reg,
const RegClassOrRegBank &RCOrRB){
VRegInfo[Reg].first = RCOrRB;
}
/// constrainRegClass - Constrain the register class of the specified virtual
/// register to be a common subclass of RC and the current register class,
/// but only if the new class has at least MinNumRegs registers. Return the
/// new register class, or NULL if no such class exists.
/// This should only be used when the constraint is known to be trivial, like
/// GR32 -> GR32_NOSP. Beware of increasing register pressure.
///
/// \note Assumes that the register has a register class assigned.
/// Use RegisterBankInfo::constrainGenericRegister in GlobalISel's
/// InstructionSelect pass and constrainRegAttrs in every other pass,
/// including non-select passes of GlobalISel, instead.
const TargetRegisterClass *constrainRegClass(unsigned Reg,
const TargetRegisterClass *RC,
unsigned MinNumRegs = 0);
/// Constrain the register class or the register bank of the virtual register
/// \p Reg (and low-level type) to be a common subclass or a common bank of
/// both registers provided respectively (and a common low-level type). Do
/// nothing if any of the attributes (classes, banks, or low-level types) of
/// the registers are deemed incompatible, or if the resulting register will
/// have a class smaller than before and of size less than \p MinNumRegs.
/// Return true if such register attributes exist, false otherwise.
///
/// \note Use this method instead of constrainRegClass and
/// RegisterBankInfo::constrainGenericRegister everywhere but SelectionDAG
/// ISel / FastISel and GlobalISel's InstructionSelect pass respectively.
bool constrainRegAttrs(unsigned Reg, unsigned ConstrainingReg,
unsigned MinNumRegs = 0);
/// recomputeRegClass - Try to find a legal super-class of Reg's register
/// class that still satisfies the constraints from the instructions using
/// Reg. Returns true if Reg was upgraded.
///
/// This method can be used after constraints have been removed from a
/// virtual register, for example after removing instructions or splitting
/// the live range.
bool recomputeRegClass(unsigned Reg);
/// createVirtualRegister - Create and return a new virtual register in the
/// function with the specified register class.
unsigned createVirtualRegister(const TargetRegisterClass *RegClass,
StringRef Name = "");
/// Create and return a new virtual register in the function with the same
/// attributes as the given register.
unsigned cloneVirtualRegister(unsigned VReg, StringRef Name = "");
/// Get the low-level type of \p Reg or LLT{} if Reg is not a generic
/// (target independent) virtual register.
LLT getType(unsigned Reg) const {
if (TargetRegisterInfo::isVirtualRegister(Reg) && VRegToType.inBounds(Reg))
return VRegToType[Reg];
return LLT{};
}
/// Set the low-level type of \p VReg to \p Ty.
void setType(unsigned VReg, LLT Ty);
/// Create and return a new generic virtual register with low-level
/// type \p Ty.
unsigned createGenericVirtualRegister(LLT Ty, StringRef Name = "");
/// Remove all types associated to virtual registers (after instruction
/// selection and constraining of all generic virtual registers).
void clearVirtRegTypes();
/// Creates a new virtual register that has no register class, register bank
/// or size assigned yet. This is only allowed to be used
/// temporarily while constructing machine instructions. Most operations are
/// undefined on an incomplete register until one of setRegClass(),
/// setRegBank() or setSize() has been called on it.
unsigned createIncompleteVirtualRegister(StringRef Name = "");
/// getNumVirtRegs - Return the number of virtual registers created.
unsigned getNumVirtRegs() const { return VRegInfo.size(); }
/// clearVirtRegs - Remove all virtual registers (after physreg assignment).
void clearVirtRegs();
/// setRegAllocationHint - Specify a register allocation hint for the
/// specified virtual register. This is typically used by target, and in case
/// of an earlier hint it will be overwritten.
void setRegAllocationHint(unsigned VReg, unsigned Type, unsigned PrefReg) {
assert(TargetRegisterInfo::isVirtualRegister(VReg));
RegAllocHints[VReg].first = Type;
RegAllocHints[VReg].second.clear();
RegAllocHints[VReg].second.push_back(PrefReg);
}
/// addRegAllocationHint - Add a register allocation hint to the hints
/// vector for VReg.
void addRegAllocationHint(unsigned VReg, unsigned PrefReg) {
assert(TargetRegisterInfo::isVirtualRegister(VReg));
RegAllocHints[VReg].second.push_back(PrefReg);
}
/// Specify the preferred (target independent) register allocation hint for
/// the specified virtual register.
void setSimpleHint(unsigned VReg, unsigned PrefReg) {
setRegAllocationHint(VReg, /*Type=*/0, PrefReg);
}
void clearSimpleHint(unsigned VReg) {
assert (RegAllocHints[VReg].first == 0 &&
"Expected to clear a non-target hint!");
RegAllocHints[VReg].second.clear();
}
/// getRegAllocationHint - Return the register allocation hint for the
/// specified virtual register. If there are many hints, this returns the
/// one with the greatest weight.
std::pair<unsigned, unsigned>
getRegAllocationHint(unsigned VReg) const {
assert(TargetRegisterInfo::isVirtualRegister(VReg));
unsigned BestHint = (RegAllocHints[VReg].second.size() ?
RegAllocHints[VReg].second[0] : 0);
return std::pair<unsigned, unsigned>(RegAllocHints[VReg].first, BestHint);
}
/// getSimpleHint - same as getRegAllocationHint except it will only return
/// a target independent hint.
unsigned getSimpleHint(unsigned VReg) const {
assert(TargetRegisterInfo::isVirtualRegister(VReg));
std::pair<unsigned, unsigned> Hint = getRegAllocationHint(VReg);
return Hint.first ? 0 : Hint.second;
}
/// getRegAllocationHints - Return a reference to the vector of all
/// register allocation hints for VReg.
const std::pair<unsigned, SmallVector<unsigned, 4>>
&getRegAllocationHints(unsigned VReg) const {
assert(TargetRegisterInfo::isVirtualRegister(VReg));
return RegAllocHints[VReg];
}
/// markUsesInDebugValueAsUndef - Mark every DBG_VALUE referencing the
/// specified register as undefined which causes the DBG_VALUE to be
/// deleted during LiveDebugVariables analysis.
void markUsesInDebugValueAsUndef(unsigned Reg) const;
/// Return true if the specified register is modified in this function.
/// This checks that no defining machine operands exist for the register or
/// any of its aliases. Definitions found on functions marked noreturn are
/// ignored, to consider them pass 'true' for optional parameter
/// SkipNoReturnDef. The register is also considered modified when it is set
/// in the UsedPhysRegMask.
bool isPhysRegModified(unsigned PhysReg, bool SkipNoReturnDef = false) const;
/// Return true if the specified register is modified or read in this
/// function. This checks that no machine operands exist for the register or
/// any of its aliases. The register is also considered used when it is set
/// in the UsedPhysRegMask.
bool isPhysRegUsed(unsigned PhysReg) const;
/// addPhysRegsUsedFromRegMask - Mark any registers not in RegMask as used.
/// This corresponds to the bit mask attached to register mask operands.
void addPhysRegsUsedFromRegMask(const uint32_t *RegMask) {
UsedPhysRegMask.setBitsNotInMask(RegMask);
}
const BitVector &getUsedPhysRegsMask() const { return UsedPhysRegMask; }
//===--------------------------------------------------------------------===//
// Reserved Register Info
//===--------------------------------------------------------------------===//
//
// The set of reserved registers must be invariant during register
// allocation. For example, the target cannot suddenly decide it needs a
// frame pointer when the register allocator has already used the frame
// pointer register for something else.
//
// These methods can be used by target hooks like hasFP() to avoid changing
// the reserved register set during register allocation.
/// freezeReservedRegs - Called by the register allocator to freeze the set
/// of reserved registers before allocation begins.
void freezeReservedRegs(const MachineFunction&);
/// reservedRegsFrozen - Returns true after freezeReservedRegs() was called
/// to ensure the set of reserved registers stays constant.
bool reservedRegsFrozen() const {
return !ReservedRegs.empty();
}
/// canReserveReg - Returns true if PhysReg can be used as a reserved
/// register. Any register can be reserved before freezeReservedRegs() is
/// called.
bool canReserveReg(unsigned PhysReg) const {
return !reservedRegsFrozen() || ReservedRegs.test(PhysReg);
}
/// getReservedRegs - Returns a reference to the frozen set of reserved
/// registers. This method should always be preferred to calling
/// TRI::getReservedRegs() when possible.
const BitVector &getReservedRegs() const {
assert(reservedRegsFrozen() &&
"Reserved registers haven't been frozen yet. "
"Use TRI::getReservedRegs().");
return ReservedRegs;
}
/// isReserved - Returns true when PhysReg is a reserved register.
///
/// Reserved registers may belong to an allocatable register class, but the
/// target has explicitly requested that they are not used.
bool isReserved(unsigned PhysReg) const {
return getReservedRegs().test(PhysReg);
}
/// Returns true when the given register unit is considered reserved.
///
/// Register units are considered reserved when for at least one of their
/// root registers, the root register and all super registers are reserved.
/// This currently iterates the register hierarchy and may be slower than
/// expected.
bool isReservedRegUnit(unsigned Unit) const;
/// isAllocatable - Returns true when PhysReg belongs to an allocatable
/// register class and it hasn't been reserved.
///
/// Allocatable registers may show up in the allocation order of some virtual
/// register, so a register allocator needs to track its liveness and
/// availability.
bool isAllocatable(unsigned PhysReg) const {
return getTargetRegisterInfo()->isInAllocatableClass(PhysReg) &&
!isReserved(PhysReg);
}
//===--------------------------------------------------------------------===//
// LiveIn Management
//===--------------------------------------------------------------------===//
/// addLiveIn - Add the specified register as a live-in. Note that it
/// is an error to add the same register to the same set more than once.
void addLiveIn(unsigned Reg, unsigned vreg = 0) {
LiveIns.push_back(std::make_pair(Reg, vreg));
}
// Iteration support for the live-ins set. It's kept in sorted order
// by register number.
using livein_iterator =
std::vector<std::pair<unsigned,unsigned>>::const_iterator;
livein_iterator livein_begin() const { return LiveIns.begin(); }
livein_iterator livein_end() const { return LiveIns.end(); }
bool livein_empty() const { return LiveIns.empty(); }
ArrayRef<std::pair<unsigned, unsigned>> liveins() const {
return LiveIns;
}
bool isLiveIn(unsigned Reg) const;
/// getLiveInPhysReg - If VReg is a live-in virtual register, return the
/// corresponding live-in physical register.
unsigned getLiveInPhysReg(unsigned VReg) const;
/// getLiveInVirtReg - If PReg is a live-in physical register, return the
/// corresponding live-in physical register.
unsigned getLiveInVirtReg(unsigned PReg) const;
/// EmitLiveInCopies - Emit copies to initialize livein virtual registers
/// into the given entry block.
void EmitLiveInCopies(MachineBasicBlock *EntryMBB,
const TargetRegisterInfo &TRI,
const TargetInstrInfo &TII);
/// Returns a mask covering all bits that can appear in lane masks of
/// subregisters of the virtual register @p Reg.
LaneBitmask getMaxLaneMaskForVReg(unsigned Reg) const;
/// defusechain_iterator - This class provides iterator support for machine
/// operands in the function that use or define a specific register. If
/// ReturnUses is true it returns uses of registers, if ReturnDefs is true it
/// returns defs. If neither are true then you are silly and it always
/// returns end(). If SkipDebug is true it skips uses marked Debug
/// when incrementing.
template<bool ReturnUses, bool ReturnDefs, bool SkipDebug,
bool ByOperand, bool ByInstr, bool ByBundle>
class defusechain_iterator
: public std::iterator<std::forward_iterator_tag, MachineInstr, ptrdiff_t> {
friend class MachineRegisterInfo;
MachineOperand *Op = nullptr;
explicit defusechain_iterator(MachineOperand *op) : Op(op) {
// If the first node isn't one we're interested in, advance to one that
// we are interested in.
if (op) {
if ((!ReturnUses && op->isUse()) ||
(!ReturnDefs && op->isDef()) ||
(SkipDebug && op->isDebug()))
advance();
}
}
void advance() {
assert(Op && "Cannot increment end iterator!");
Op = getNextOperandForReg(Op);
// All defs come before the uses, so stop def_iterator early.
if (!ReturnUses) {
if (Op) {
if (Op->isUse())
Op = nullptr;
else
assert(!Op->isDebug() && "Can't have debug defs");
}
} else {
// If this is an operand we don't care about, skip it.
while (Op && ((!ReturnDefs && Op->isDef()) ||
(SkipDebug && Op->isDebug())))
Op = getNextOperandForReg(Op);
}
}
public:
using reference = std::iterator<std::forward_iterator_tag,
MachineInstr, ptrdiff_t>::reference;
using pointer = std::iterator<std::forward_iterator_tag,
MachineInstr, ptrdiff_t>::pointer;
defusechain_iterator() = default;
bool operator==(const defusechain_iterator &x) const {
return Op == x.Op;
}
bool operator!=(const defusechain_iterator &x) const {
return !operator==(x);
}
/// atEnd - return true if this iterator is equal to reg_end() on the value.
bool atEnd() const { return Op == nullptr; }
// Iterator traversal: forward iteration only
defusechain_iterator &operator++() { // Preincrement
assert(Op && "Cannot increment end iterator!");
if (ByOperand)
advance();
else if (ByInstr) {
MachineInstr *P = Op->getParent();
do {
advance();
} while (Op && Op->getParent() == P);
} else if (ByBundle) {
MachineBasicBlock::instr_iterator P =
getBundleStart(Op->getParent()->getIterator());
do {
advance();
} while (Op && getBundleStart(Op->getParent()->getIterator()) == P);
}
return *this;
}
defusechain_iterator operator++(int) { // Postincrement
defusechain_iterator tmp = *this; ++*this; return tmp;
}
/// getOperandNo - Return the operand # of this MachineOperand in its
/// MachineInstr.
unsigned getOperandNo() const {
assert(Op && "Cannot dereference end iterator!");
return Op - &Op->getParent()->getOperand(0);
}
// Retrieve a reference to the current operand.
MachineOperand &operator*() const {
assert(Op && "Cannot dereference end iterator!");
return *Op;
}
MachineOperand *operator->() const {
assert(Op && "Cannot dereference end iterator!");
return Op;
}
};
/// defusechain_iterator - This class provides iterator support for machine
/// operands in the function that use or define a specific register. If
/// ReturnUses is true it returns uses of registers, if ReturnDefs is true it
/// returns defs. If neither are true then you are silly and it always
/// returns end(). If SkipDebug is true it skips uses marked Debug
/// when incrementing.
template<bool ReturnUses, bool ReturnDefs, bool SkipDebug,
bool ByOperand, bool ByInstr, bool ByBundle>
class defusechain_instr_iterator
: public std::iterator<std::forward_iterator_tag, MachineInstr, ptrdiff_t> {
friend class MachineRegisterInfo;
MachineOperand *Op = nullptr;
explicit defusechain_instr_iterator(MachineOperand *op) : Op(op) {
// If the first node isn't one we're interested in, advance to one that
// we are interested in.
if (op) {
if ((!ReturnUses && op->isUse()) ||
(!ReturnDefs && op->isDef()) ||
(SkipDebug && op->isDebug()))
advance();
}
}
void advance() {
assert(Op && "Cannot increment end iterator!");
Op = getNextOperandForReg(Op);
// All defs come before the uses, so stop def_iterator early.
if (!ReturnUses) {
if (Op) {
if (Op->isUse())
Op = nullptr;
else
assert(!Op->isDebug() && "Can't have debug defs");
}
} else {
// If this is an operand we don't care about, skip it.
while (Op && ((!ReturnDefs && Op->isDef()) ||
(SkipDebug && Op->isDebug())))
Op = getNextOperandForReg(Op);
}
}
public:
using reference = std::iterator<std::forward_iterator_tag,
MachineInstr, ptrdiff_t>::reference;
using pointer = std::iterator<std::forward_iterator_tag,
MachineInstr, ptrdiff_t>::pointer;
defusechain_instr_iterator() = default;
bool operator==(const defusechain_instr_iterator &x) const {
return Op == x.Op;
}
bool operator!=(const defusechain_instr_iterator &x) const {
return !operator==(x);
}
/// atEnd - return true if this iterator is equal to reg_end() on the value.
bool atEnd() const { return Op == nullptr; }
// Iterator traversal: forward iteration only
defusechain_instr_iterator &operator++() { // Preincrement
assert(Op && "Cannot increment end iterator!");
if (ByOperand)
advance();
else if (ByInstr) {
MachineInstr *P = Op->getParent();
do {
advance();
} while (Op && Op->getParent() == P);
} else if (ByBundle) {
MachineBasicBlock::instr_iterator P =
getBundleStart(Op->getParent()->getIterator());
do {
advance();
} while (Op && getBundleStart(Op->getParent()->getIterator()) == P);
}
return *this;
}
defusechain_instr_iterator operator++(int) { // Postincrement
defusechain_instr_iterator tmp = *this; ++*this; return tmp;
}
// Retrieve a reference to the current operand.
MachineInstr &operator*() const {
assert(Op && "Cannot dereference end iterator!");
if (ByBundle)
return *getBundleStart(Op->getParent()->getIterator());
return *Op->getParent();
}
MachineInstr *operator->() const { return &operator*(); }
};
};
/// Iterate over the pressure sets affected by the given physical or virtual
/// register. If Reg is physical, it must be a register unit (from
/// MCRegUnitIterator).
class PSetIterator {
const int *PSet = nullptr;
unsigned Weight = 0;
public:
PSetIterator() = default;
PSetIterator(unsigned RegUnit, const MachineRegisterInfo *MRI) {
const TargetRegisterInfo *TRI = MRI->getTargetRegisterInfo();
if (TargetRegisterInfo::isVirtualRegister(RegUnit)) {
const TargetRegisterClass *RC = MRI->getRegClass(RegUnit);
PSet = TRI->getRegClassPressureSets(RC);
Weight = TRI->getRegClassWeight(RC).RegWeight;
}
else {
PSet = TRI->getRegUnitPressureSets(RegUnit);
Weight = TRI->getRegUnitWeight(RegUnit);
}
if (*PSet == -1)
PSet = nullptr;
}
bool isValid() const { return PSet; }
unsigned getWeight() const { return Weight; }
unsigned operator*() const { return *PSet; }
void operator++() {
assert(isValid() && "Invalid PSetIterator.");
++PSet;
if (*PSet == -1)
PSet = nullptr;
}
};
inline PSetIterator MachineRegisterInfo::
getPressureSets(unsigned RegUnit) const {
return PSetIterator(RegUnit, this);
}
} // end namespace llvm
#endif // LLVM_CODEGEN_MACHINEREGISTERINFO_H