llvm-6502/include/llvm/Target/MRegisterInfo.h

332 lines
13 KiB
C++

//===- Target/MRegisterInfo.h - Target Register Information -----*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file was developed by the LLVM research group and 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_MREGISTERINFO_H
#define LLVM_TARGET_MREGISTERINFO_H
#include "llvm/CodeGen/MachineBasicBlock.h"
#include <cassert>
#include <functional>
namespace llvm {
class Type;
class MachineFunction;
class MachineInstr;
/// MRegisterDesc - 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.
///
struct MRegisterDesc {
const char *Name; // Assembly language name for the register
const unsigned *AliasSet; // Register Alias Set, described above
unsigned char SpillSize; // Size of this register in bytes
unsigned char SpillAlignment; // Alignment of stack slot for this reg
};
class TargetRegisterClass {
public:
typedef const unsigned* iterator;
typedef const unsigned* const_iterator;
private:
const unsigned RegSize, Alignment; // Size & Alignment of register in bytes
const iterator RegsBegin, RegsEnd;
public:
TargetRegisterClass(unsigned RS, unsigned Al, iterator RB, iterator RE)
: RegSize(RS), Alignment(Al), RegsBegin(RB), RegsEnd(RE) {}
virtual ~TargetRegisterClass() {} // Allow subclasses
// 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 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 {
for (iterator I = begin(), E = end(); I != E; ++I)
if (*I == Reg) return true;
return false;
}
/// 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(MachineFunction &MF) const {
return begin();
}
virtual iterator allocation_order_end(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; }
};
/// MRegisterInfo base class - We assume that the target defines a static array
/// of MRegisterDesc 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 MRegisterInfo {
public:
typedef const TargetRegisterClass * const * regclass_iterator;
private:
const MRegisterDesc *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:
MRegisterInfo(const MRegisterDesc *D, unsigned NR,
regclass_iterator RegClassBegin, regclass_iterator RegClassEnd,
int CallFrameSetupOpcode = -1, int CallFrameDestroyOpcode = -1);
virtual ~MRegisterInfo();
public:
enum { // Define some target independent constants
/// NoRegister - This 'hard' register is a 'noop' register for all backends.
/// This is used as the destination register for instructions that do not
/// produce a value. Some frontends may use this as an operand register to
/// mean special things, for example, the Sparc backend uses R0 to mean %g0
/// which always PRODUCES the value 0. The X86 backend does not use this
/// value as an operand register, except for memory references.
///
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;
}
/// getAllocatableSet - Returns a bitset indexed by register number
/// indicating if a register is allocatable or not.
std::vector<bool> getAllocatableSet(MachineFunction &MF) const;
const MRegisterDesc &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 MRegisterDesc &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;
}
/// getName - Return the symbolic target specific name for the specified
/// physical register.
const char *getName(unsigned RegNo) const {
return get(RegNo).Name;
}
/// getSpillSize - Return the size in bits required of a stack slot used to
/// spill register into.
unsigned getSpillSize(unsigned RegNo) const {
return get(RegNo).SpillSize;
}
/// getSpillAlignment - Return the alignment required by a stack slot used to
/// spill register into.
unsigned getSpillAlignment(unsigned RegNo) const {
return get(RegNo).SpillAlignment;
}
/// 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 {
for (const unsigned *Alias = getAliasSet(regA); *Alias; ++Alias)
if (*Alias == regB) return true;
return false;
}
virtual const unsigned* getCalleeSaveRegs() const = 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 regclass_end()-regclass_begin();
}
//===--------------------------------------------------------------------===//
// Interfaces used by the register allocator and stack frame
// manipulation passes to move data around between registers,
// immediates and memory. The return value is the number of
// instructions added to (negative if removed from) the basic block.
//
virtual void storeRegToStackSlot(MachineBasicBlock &MBB,
MachineBasicBlock::iterator MI,
unsigned SrcReg, int FrameIndex) const = 0;
virtual void loadRegFromStackSlot(MachineBasicBlock &MBB,
MachineBasicBlock::iterator MI,
unsigned DestReg, int FrameIndex) const = 0;
virtual void copyRegToReg(MachineBasicBlock &MBB,
MachineBasicBlock::iterator MI,
unsigned DestReg, unsigned SrcReg,
const TargetRegisterClass *RC) const = 0;
/// foldMemoryOperand - Attempt to fold a load or store of the
/// specified stack slot into the specified machine instruction for
/// the specified operand. If this is possible, a new instruction
/// is returned with the specified operand folded, otherwise NULL is
/// returned. The client is responsible for removing the old
/// instruction and adding the new one in the instruction stream
virtual MachineInstr* foldMemoryOperand(MachineInstr* MI,
unsigned OpNum,
int FrameIndex) const {
return 0;
}
/// 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!");
}
/// 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. The return value
/// is the number of instructions added to (negative if removed from) the
/// basic block
///
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. The return value is the number of instructions
/// added to (negative if removed from) the basic block.
///
virtual void eliminateFrameIndex(MachineBasicBlock::iterator MI) const = 0;
/// emitProlog/emitEpilog - These methods insert prolog and epilog code into
/// the function. The return value is the number of instructions
/// added to (negative if removed from) the basic block (entry for prologue).
///
virtual void emitPrologue(MachineFunction &MF) const = 0;
virtual void emitEpilogue(MachineFunction &MF,
MachineBasicBlock &MBB) const = 0;
};
// This is useful when building DenseMaps keyed on virtual registers
struct VirtReg2IndexFunctor : std::unary_function<unsigned, unsigned> {
unsigned operator()(unsigned Reg) const {
return Reg - MRegisterInfo::FirstVirtualRegister;
}
};
} // End llvm namespace
#endif