//===- llvm/CodeGen/MachineRegisterInfo.h -----------------------*- C++ -*-===// // // The LLVM Compiler Infrastructure // // This file is distributed under the University of Illinois Open Source // License. See LICENSE.TXT for details. // //===----------------------------------------------------------------------===// // // 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 = DenseMap<unsigned, LLT>; /// Map generic virtual registers to their actual size. mutable std::unique_ptr<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 to be a common subclass and a common bank of both registers /// provided respectively. 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 Assumes that each register has either a low-level type or a class /// assigned, but not both. 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); /// Accessor for VRegToType. This accessor should only be used /// by global-isel related work. VRegToTypeMap &getVRegToType() const { if (!VRegToType) VRegToType.reset(new VRegToTypeMap); return *VRegToType.get(); } /// Get the low-level type of \p VReg or LLT{} if VReg is not a generic /// (target independent) virtual register. LLT getType(unsigned VReg) const; /// 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); /// 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