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Diffstat (limited to 'include/llvm/Target/TargetRegisterInfo.h')
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diff --git a/include/llvm/Target/TargetRegisterInfo.h b/include/llvm/Target/TargetRegisterInfo.h new file mode 100644 index 000000000000..0218bfdb2ae3 --- /dev/null +++ b/include/llvm/Target/TargetRegisterInfo.h @@ -0,0 +1,656 @@ +//=== Target/TargetRegisterInfo.h - Target Register Information -*- C++ -*-===// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// +// +// This file describes an abstract interface used to get information about a +// target machines register file. This information is used for a variety of +// purposed, especially register allocation. +// +//===----------------------------------------------------------------------===// + +#ifndef LLVM_TARGET_TARGETREGISTERINFO_H +#define LLVM_TARGET_TARGETREGISTERINFO_H + +#include "llvm/CodeGen/MachineBasicBlock.h" +#include "llvm/CodeGen/ValueTypes.h" +#include "llvm/ADT/DenseSet.h" +#include <cassert> +#include <functional> + +namespace llvm { + +class BitVector; +class MachineFunction; +class MachineMove; +class RegScavenger; + +/// TargetRegisterDesc - This record contains all of the information known about +/// a particular register. The AliasSet field (if not null) contains a pointer +/// to a Zero terminated array of registers that this register aliases. This is +/// needed for architectures like X86 which have AL alias AX alias EAX. +/// Registers that this does not apply to simply should set this to null. +/// The SubRegs field is a zero terminated array of registers that are +/// sub-registers of the specific register, e.g. AL, AH are sub-registers of AX. +/// The SuperRegs field is a zero terminated array of registers that are +/// super-registers of the specific register, e.g. RAX, EAX, are super-registers +/// of AX. +/// +struct TargetRegisterDesc { + const char *AsmName; // Assembly language name for the register + const char *Name; // Printable name for the reg (for debugging) + const unsigned *AliasSet; // Register Alias Set, described above + const unsigned *SubRegs; // Sub-register set, described above + const unsigned *SuperRegs; // Super-register set, described above +}; + +class TargetRegisterClass { +public: + typedef const unsigned* iterator; + typedef const unsigned* const_iterator; + + typedef const MVT* vt_iterator; + typedef const TargetRegisterClass* const * sc_iterator; +private: + unsigned ID; + const char *Name; + const vt_iterator VTs; + const sc_iterator SubClasses; + const sc_iterator SuperClasses; + const sc_iterator SubRegClasses; + const sc_iterator SuperRegClasses; + const unsigned RegSize, Alignment; // Size & Alignment of register in bytes + const int CopyCost; + const iterator RegsBegin, RegsEnd; + DenseSet<unsigned> RegSet; +public: + TargetRegisterClass(unsigned id, + const char *name, + const MVT *vts, + const TargetRegisterClass * const *subcs, + const TargetRegisterClass * const *supcs, + const TargetRegisterClass * const *subregcs, + const TargetRegisterClass * const *superregcs, + unsigned RS, unsigned Al, int CC, + iterator RB, iterator RE) + : ID(id), Name(name), VTs(vts), SubClasses(subcs), SuperClasses(supcs), + SubRegClasses(subregcs), SuperRegClasses(superregcs), + RegSize(RS), Alignment(Al), CopyCost(CC), RegsBegin(RB), RegsEnd(RE) { + for (iterator I = RegsBegin, E = RegsEnd; I != E; ++I) + RegSet.insert(*I); + } + virtual ~TargetRegisterClass() {} // Allow subclasses + + /// getID() - Return the register class ID number. + /// + unsigned getID() const { return ID; } + + /// getName() - Return the register class name for debugging. + /// + const char *getName() const { return Name; } + + /// begin/end - Return all of the registers in this class. + /// + iterator begin() const { return RegsBegin; } + iterator end() const { return RegsEnd; } + + /// getNumRegs - Return the number of registers in this class. + /// + unsigned getNumRegs() const { return (unsigned)(RegsEnd-RegsBegin); } + + /// getRegister - Return the specified register in the class. + /// + unsigned getRegister(unsigned i) const { + assert(i < getNumRegs() && "Register number out of range!"); + return RegsBegin[i]; + } + + /// contains - Return true if the specified register is included in this + /// register class. + bool contains(unsigned Reg) const { + return RegSet.count(Reg); + } + + /// hasType - return true if this TargetRegisterClass has the ValueType vt. + /// + bool hasType(MVT vt) const { + for(int i = 0; VTs[i] != MVT::Other; ++i) + if (VTs[i] == vt) + return true; + return false; + } + + /// vt_begin / vt_end - Loop over all of the value types that can be + /// represented by values in this register class. + vt_iterator vt_begin() const { + return VTs; + } + + vt_iterator vt_end() const { + vt_iterator I = VTs; + while (*I != MVT::Other) ++I; + return I; + } + + /// subregclasses_begin / subregclasses_end - Loop over all of + /// the subreg register classes of this register class. + sc_iterator subregclasses_begin() const { + return SubRegClasses; + } + + sc_iterator subregclasses_end() const { + sc_iterator I = SubRegClasses; + while (*I != NULL) ++I; + return I; + } + + /// getSubRegisterRegClass - Return the register class of subregisters with + /// index SubIdx, or NULL if no such class exists. + const TargetRegisterClass* getSubRegisterRegClass(unsigned SubIdx) const { + assert(SubIdx>0 && "Invalid subregister index"); + for (unsigned s = 0; s != SubIdx-1; ++s) + if (!SubRegClasses[s]) + return NULL; + return SubRegClasses[SubIdx-1]; + } + + /// superregclasses_begin / superregclasses_end - Loop over all of + /// the superreg register classes of this register class. + sc_iterator superregclasses_begin() const { + return SuperRegClasses; + } + + sc_iterator superregclasses_end() const { + sc_iterator I = SuperRegClasses; + while (*I != NULL) ++I; + return I; + } + + /// hasSubClass - return true if the the specified TargetRegisterClass + /// is a proper subset of this TargetRegisterClass. + bool hasSubClass(const TargetRegisterClass *cs) const { + for (int i = 0; SubClasses[i] != NULL; ++i) + if (SubClasses[i] == cs) + return true; + return false; + } + + /// subclasses_begin / subclasses_end - Loop over all of the classes + /// that are proper subsets of this register class. + sc_iterator subclasses_begin() const { + return SubClasses; + } + + sc_iterator subclasses_end() const { + sc_iterator I = SubClasses; + while (*I != NULL) ++I; + return I; + } + + /// hasSuperClass - return true if the specified TargetRegisterClass is a + /// proper superset of this TargetRegisterClass. + bool hasSuperClass(const TargetRegisterClass *cs) const { + for (int i = 0; SuperClasses[i] != NULL; ++i) + if (SuperClasses[i] == cs) + return true; + return false; + } + + /// superclasses_begin / superclasses_end - Loop over all of the classes + /// that are proper supersets of this register class. + sc_iterator superclasses_begin() const { + return SuperClasses; + } + + sc_iterator superclasses_end() const { + sc_iterator I = SuperClasses; + while (*I != NULL) ++I; + return I; + } + + /// isASubClass - return true if this TargetRegisterClass is a subset + /// class of at least one other TargetRegisterClass. + bool isASubClass() const { + return SuperClasses[0] != 0; + } + + /// allocation_order_begin/end - These methods define a range of registers + /// which specify the registers in this class that are valid to register + /// allocate, and the preferred order to allocate them in. For example, + /// callee saved registers should be at the end of the list, because it is + /// cheaper to allocate caller saved registers. + /// + /// These methods take a MachineFunction argument, which can be used to tune + /// the allocatable registers based on the characteristics of the function. + /// One simple example is that the frame pointer register can be used if + /// frame-pointer-elimination is performed. + /// + /// By default, these methods return all registers in the class. + /// + virtual iterator allocation_order_begin(const MachineFunction &MF) const { + return begin(); + } + virtual iterator allocation_order_end(const MachineFunction &MF) const { + return end(); + } + + /// getSize - Return the size of the register in bytes, which is also the size + /// of a stack slot allocated to hold a spilled copy of this register. + unsigned getSize() const { return RegSize; } + + /// getAlignment - Return the minimum required alignment for a register of + /// this class. + unsigned getAlignment() const { return Alignment; } + + /// getCopyCost - Return the cost of copying a value between two registers in + /// this class. A negative number means the register class is very expensive + /// to copy e.g. status flag register classes. + int getCopyCost() const { return CopyCost; } +}; + + +/// TargetRegisterInfo base class - We assume that the target defines a static +/// array of TargetRegisterDesc objects that represent all of the machine +/// registers that the target has. As such, we simply have to track a pointer +/// to this array so that we can turn register number into a register +/// descriptor. +/// +class TargetRegisterInfo { +protected: + const unsigned* SubregHash; + const unsigned SubregHashSize; + const unsigned* SuperregHash; + const unsigned SuperregHashSize; + const unsigned* AliasesHash; + const unsigned AliasesHashSize; +public: + typedef const TargetRegisterClass * const * regclass_iterator; +private: + const TargetRegisterDesc *Desc; // Pointer to the descriptor array + unsigned NumRegs; // Number of entries in the array + + regclass_iterator RegClassBegin, RegClassEnd; // List of regclasses + + int CallFrameSetupOpcode, CallFrameDestroyOpcode; +protected: + TargetRegisterInfo(const TargetRegisterDesc *D, unsigned NR, + regclass_iterator RegClassBegin, + regclass_iterator RegClassEnd, + int CallFrameSetupOpcode = -1, + int CallFrameDestroyOpcode = -1, + const unsigned* subregs = 0, + const unsigned subregsize = 0, + const unsigned* superregs = 0, + const unsigned superregsize = 0, + const unsigned* aliases = 0, + const unsigned aliasessize = 0); + virtual ~TargetRegisterInfo(); +public: + + enum { // Define some target independent constants + /// NoRegister - This physical register is not a real target register. It + /// is useful as a sentinal. + NoRegister = 0, + + /// FirstVirtualRegister - This is the first register number that is + /// considered to be a 'virtual' register, which is part of the SSA + /// namespace. This must be the same for all targets, which means that each + /// target is limited to 1024 registers. + FirstVirtualRegister = 1024 + }; + + /// isPhysicalRegister - Return true if the specified register number is in + /// the physical register namespace. + static bool isPhysicalRegister(unsigned Reg) { + assert(Reg && "this is not a register!"); + return Reg < FirstVirtualRegister; + } + + /// isVirtualRegister - Return true if the specified register number is in + /// the virtual register namespace. + static bool isVirtualRegister(unsigned Reg) { + assert(Reg && "this is not a register!"); + return Reg >= FirstVirtualRegister; + } + + /// getPhysicalRegisterRegClass - Returns the Register Class of a physical + /// register of the given type. If type is MVT::Other, then just return any + /// register class the register belongs to. + virtual const TargetRegisterClass * + getPhysicalRegisterRegClass(unsigned Reg, MVT VT = MVT::Other) const; + + /// getAllocatableSet - Returns a bitset indexed by register number + /// indicating if a register is allocatable or not. If a register class is + /// specified, returns the subset for the class. + BitVector getAllocatableSet(MachineFunction &MF, + const TargetRegisterClass *RC = NULL) const; + + const TargetRegisterDesc &operator[](unsigned RegNo) const { + assert(RegNo < NumRegs && + "Attempting to access record for invalid register number!"); + return Desc[RegNo]; + } + + /// Provide a get method, equivalent to [], but more useful if we have a + /// pointer to this object. + /// + const TargetRegisterDesc &get(unsigned RegNo) const { + return operator[](RegNo); + } + + /// getAliasSet - Return the set of registers aliased by the specified + /// register, or a null list of there are none. The list returned is zero + /// terminated. + /// + const unsigned *getAliasSet(unsigned RegNo) const { + return get(RegNo).AliasSet; + } + + /// getSubRegisters - Return the list of registers that are sub-registers of + /// the specified register, or a null list of there are none. The list + /// returned is zero terminated and sorted according to super-sub register + /// relations. e.g. X86::RAX's sub-register list is EAX, AX, AL, AH. + /// + const unsigned *getSubRegisters(unsigned RegNo) const { + return get(RegNo).SubRegs; + } + + /// getSuperRegisters - Return the list of registers that are super-registers + /// of the specified register, or a null list of there are none. The list + /// returned is zero terminated and sorted according to super-sub register + /// relations. e.g. X86::AL's super-register list is RAX, EAX, AX. + /// + const unsigned *getSuperRegisters(unsigned RegNo) const { + return get(RegNo).SuperRegs; + } + + /// getAsmName - Return the symbolic target-specific name for the + /// specified physical register. + const char *getAsmName(unsigned RegNo) const { + return get(RegNo).AsmName; + } + + /// getName - Return the human-readable symbolic target-specific name for the + /// specified physical register. + const char *getName(unsigned RegNo) const { + return get(RegNo).Name; + } + + /// getNumRegs - Return the number of registers this target has (useful for + /// sizing arrays holding per register information) + unsigned getNumRegs() const { + return NumRegs; + } + + /// areAliases - Returns true if the two registers alias each other, false + /// otherwise + bool areAliases(unsigned regA, unsigned regB) const { + size_t index = (regA + regB * 37) & (AliasesHashSize-1); + unsigned ProbeAmt = 0; + while (AliasesHash[index*2] != 0 && + AliasesHash[index*2+1] != 0) { + if (AliasesHash[index*2] == regA && AliasesHash[index*2+1] == regB) + return true; + + index = (index + ProbeAmt) & (AliasesHashSize-1); + ProbeAmt += 2; + } + + return false; + } + + /// regsOverlap - Returns true if the two registers are equal or alias each + /// other. The registers may be virtual register. + bool regsOverlap(unsigned regA, unsigned regB) const { + if (regA == regB) + return true; + + if (isVirtualRegister(regA) || isVirtualRegister(regB)) + return false; + return areAliases(regA, regB); + } + + /// isSubRegister - Returns true if regB is a sub-register of regA. + /// + bool isSubRegister(unsigned regA, unsigned regB) const { + // SubregHash is a simple quadratically probed hash table. + size_t index = (regA + regB * 37) & (SubregHashSize-1); + unsigned ProbeAmt = 2; + while (SubregHash[index*2] != 0 && + SubregHash[index*2+1] != 0) { + if (SubregHash[index*2] == regA && SubregHash[index*2+1] == regB) + return true; + + index = (index + ProbeAmt) & (SubregHashSize-1); + ProbeAmt += 2; + } + + return false; + } + + /// isSuperRegister - Returns true if regB is a super-register of regA. + /// + bool isSuperRegister(unsigned regA, unsigned regB) const { + // SuperregHash is a simple quadratically probed hash table. + size_t index = (regA + regB * 37) & (SuperregHashSize-1); + unsigned ProbeAmt = 2; + while (SuperregHash[index*2] != 0 && + SuperregHash[index*2+1] != 0) { + if (SuperregHash[index*2] == regA && SuperregHash[index*2+1] == regB) + return true; + + index = (index + ProbeAmt) & (SuperregHashSize-1); + ProbeAmt += 2; + } + + return false; + } + + /// getCalleeSavedRegs - Return a null-terminated list of all of the + /// callee saved registers on this target. The register should be in the + /// order of desired callee-save stack frame offset. The first register is + /// closed to the incoming stack pointer if stack grows down, and vice versa. + virtual const unsigned* getCalleeSavedRegs(const MachineFunction *MF = 0) + const = 0; + + /// getCalleeSavedRegClasses - Return a null-terminated list of the preferred + /// register classes to spill each callee saved register with. The order and + /// length of this list match the getCalleeSaveRegs() list. + virtual const TargetRegisterClass* const *getCalleeSavedRegClasses( + const MachineFunction *MF) const =0; + + /// getReservedRegs - Returns a bitset indexed by physical register number + /// indicating if a register is a special register that has particular uses + /// and should be considered unavailable at all times, e.g. SP, RA. This is + /// used by register scavenger to determine what registers are free. + virtual BitVector getReservedRegs(const MachineFunction &MF) const = 0; + + /// getSubReg - Returns the physical register number of sub-register "Index" + /// for physical register RegNo. Return zero if the sub-register does not + /// exist. + virtual unsigned getSubReg(unsigned RegNo, unsigned Index) const = 0; + + /// getMatchingSuperReg - Return a super-register of the specified register + /// Reg so its sub-register of index SubIdx is Reg. + unsigned getMatchingSuperReg(unsigned Reg, unsigned SubIdx, + const TargetRegisterClass *RC) const { + for (const unsigned *SRs = getSuperRegisters(Reg); unsigned SR = *SRs;++SRs) + if (Reg == getSubReg(SR, SubIdx) && RC->contains(SR)) + return SR; + return 0; + } + + //===--------------------------------------------------------------------===// + // Register Class Information + // + + /// Register class iterators + /// + regclass_iterator regclass_begin() const { return RegClassBegin; } + regclass_iterator regclass_end() const { return RegClassEnd; } + + unsigned getNumRegClasses() const { + return (unsigned)(regclass_end()-regclass_begin()); + } + + /// getRegClass - Returns the register class associated with the enumeration + /// value. See class TargetOperandInfo. + const TargetRegisterClass *getRegClass(unsigned i) const { + assert(i <= getNumRegClasses() && "Register Class ID out of range"); + return i ? RegClassBegin[i - 1] : NULL; + } + + /// getPointerRegClass - Returns a TargetRegisterClass used for pointer + /// values. + virtual const TargetRegisterClass *getPointerRegClass() const { + assert(0 && "Target didn't implement getPointerRegClass!"); + return 0; // Must return a value in order to compile with VS 2005 + } + + /// getCrossCopyRegClass - Returns a legal register class to copy a register + /// in the specified class to or from. Returns NULL if it is possible to copy + /// between a two registers of the specified class. + virtual const TargetRegisterClass * + getCrossCopyRegClass(const TargetRegisterClass *RC) const { + return NULL; + } + + /// targetHandlesStackFrameRounding - Returns true if the target is + /// responsible for rounding up the stack frame (probably at emitPrologue + /// time). + virtual bool targetHandlesStackFrameRounding() const { + return false; + } + + /// requiresRegisterScavenging - returns true if the target requires (and can + /// make use of) the register scavenger. + virtual bool requiresRegisterScavenging(const MachineFunction &MF) const { + return false; + } + + /// hasFP - Return true if the specified function should have a dedicated + /// frame pointer register. For most targets this is true only if the function + /// has variable sized allocas or if frame pointer elimination is disabled. + virtual bool hasFP(const MachineFunction &MF) const = 0; + + // hasReservedCallFrame - Under normal circumstances, when a frame pointer is + // not required, we reserve argument space for call sites in the function + // immediately on entry to the current function. This eliminates the need for + // add/sub sp brackets around call sites. Returns true if the call frame is + // included as part of the stack frame. + virtual bool hasReservedCallFrame(MachineFunction &MF) const { + return !hasFP(MF); + } + + // needsStackRealignment - true if storage within the function requires the + // stack pointer to be aligned more than the normal calling convention calls + // for. + virtual bool needsStackRealignment(const MachineFunction &MF) const { + return false; + } + + /// getCallFrameSetup/DestroyOpcode - These methods return the opcode of the + /// frame setup/destroy instructions if they exist (-1 otherwise). Some + /// targets use pseudo instructions in order to abstract away the difference + /// between operating with a frame pointer and operating without, through the + /// use of these two instructions. + /// + int getCallFrameSetupOpcode() const { return CallFrameSetupOpcode; } + int getCallFrameDestroyOpcode() const { return CallFrameDestroyOpcode; } + + /// eliminateCallFramePseudoInstr - This method is called during prolog/epilog + /// code insertion to eliminate call frame setup and destroy pseudo + /// instructions (but only if the Target is using them). It is responsible + /// for eliminating these instructions, replacing them with concrete + /// instructions. This method need only be implemented if using call frame + /// setup/destroy pseudo instructions. + /// + virtual void + eliminateCallFramePseudoInstr(MachineFunction &MF, + MachineBasicBlock &MBB, + MachineBasicBlock::iterator MI) const { + assert(getCallFrameSetupOpcode()== -1 && getCallFrameDestroyOpcode()== -1 && + "eliminateCallFramePseudoInstr must be implemented if using" + " call frame setup/destroy pseudo instructions!"); + assert(0 && "Call Frame Pseudo Instructions do not exist on this target!"); + } + + /// processFunctionBeforeCalleeSavedScan - This method is called immediately + /// before PrologEpilogInserter scans the physical registers used to determine + /// what callee saved registers should be spilled. This method is optional. + virtual void processFunctionBeforeCalleeSavedScan(MachineFunction &MF, + RegScavenger *RS = NULL) const { + + } + + /// processFunctionBeforeFrameFinalized - This method is called immediately + /// before the specified functions frame layout (MF.getFrameInfo()) is + /// finalized. Once the frame is finalized, MO_FrameIndex operands are + /// replaced with direct constants. This method is optional. + /// + virtual void processFunctionBeforeFrameFinalized(MachineFunction &MF) const { + } + + /// eliminateFrameIndex - This method must be overriden to eliminate abstract + /// frame indices from instructions which may use them. The instruction + /// referenced by the iterator contains an MO_FrameIndex operand which must be + /// eliminated by this method. This method may modify or replace the + /// specified instruction, as long as it keeps the iterator pointing the the + /// finished product. SPAdj is the SP adjustment due to call frame setup + /// instruction. + virtual void eliminateFrameIndex(MachineBasicBlock::iterator MI, + int SPAdj, RegScavenger *RS=NULL) const = 0; + + /// emitProlog/emitEpilog - These methods insert prolog and epilog code into + /// the function. + virtual void emitPrologue(MachineFunction &MF) const = 0; + virtual void emitEpilogue(MachineFunction &MF, + MachineBasicBlock &MBB) const = 0; + + //===--------------------------------------------------------------------===// + /// Debug information queries. + + /// getDwarfRegNum - Map a target register to an equivalent dwarf register + /// number. Returns -1 if there is no equivalent value. The second + /// parameter allows targets to use different numberings for EH info and + /// debugging info. + virtual int getDwarfRegNum(unsigned RegNum, bool isEH) const = 0; + + /// getFrameRegister - This method should return the register used as a base + /// for values allocated in the current stack frame. + virtual unsigned getFrameRegister(MachineFunction &MF) const = 0; + + /// getFrameIndexOffset - Returns the displacement from the frame register to + /// the stack frame of the specified index. + virtual int getFrameIndexOffset(MachineFunction &MF, int FI) const; + + /// getRARegister - This method should return the register where the return + /// address can be found. + virtual unsigned getRARegister() const = 0; + + /// getInitialFrameState - Returns a list of machine moves that are assumed + /// on entry to all functions. Note that LabelID is ignored (assumed to be + /// the beginning of the function.) + virtual void getInitialFrameState(std::vector<MachineMove> &Moves) const; +}; + + +// This is useful when building IndexedMaps keyed on virtual registers +struct VirtReg2IndexFunctor : std::unary_function<unsigned, unsigned> { + unsigned operator()(unsigned Reg) const { + return Reg - TargetRegisterInfo::FirstVirtualRegister; + } +}; + +/// getCommonSubClass - find the largest common subclass of A and B. Return NULL +/// if there is no common subclass. +const TargetRegisterClass *getCommonSubClass(const TargetRegisterClass *A, + const TargetRegisterClass *B); + +} // End llvm namespace + +#endif |