1 //===- Target/MRegisterInfo.h - Target Register Information -------*-C++-*-===//
3 // This file describes an abstract interface used to get information about a
4 // target machines register file. This information is used for a variety of
5 // purposed, especially register allocation.
7 //===----------------------------------------------------------------------===//
9 #ifndef LLVM_TARGET_MREGISTERINFO_H
10 #define LLVM_TARGET_MREGISTERINFO_H
12 #include "llvm/CodeGen/MachineBasicBlock.h"
15 class MachineFunction;
17 /// MRegisterDesc - This record contains all of the information known about a
18 /// particular register. The AliasSet field (if not null) contains a pointer to
19 /// a Zero terminated array of registers that this register aliases. This is
20 /// needed for architectures like X86 which have AL alias AX alias EAX.
21 /// Registers that this does not apply to simply should set this to null.
23 struct MRegisterDesc {
24 const char *Name; // Assembly language name for the register
25 const unsigned *AliasSet; // Register Alias Set, described above
26 unsigned Flags; // Flags identifying register properties (below)
27 unsigned TSFlags; // Target Specific Flags
30 /// MRF namespace - This namespace contains flags that pertain to machine
33 namespace MRF { // MRF = Machine Register Flags
35 Other = 0 << 0, // This is a non-standard register
36 INT8 = 1 << 0, // This is an 8 bit integer register
37 INT16 = 1 << 1, // This is a 16 bit integer register
38 INT32 = 1 << 2, // This is a 32 bit integer register
39 INT64 = 1 << 3, // This is a 64 bit integer register
40 INT128 = 1 << 4, // This is a 128 bit integer register
42 FP32 = 1 << 5, // This is a 32 bit floating point register
43 FP64 = 1 << 6, // This is a 64 bit floating point register
44 FP80 = 1 << 7, // This is a 80 bit floating point register
45 FP128 = 1 << 8, // This is a 128 bit floating point register
49 class TargetRegisterClass {
51 typedef const unsigned* iterator;
52 typedef const unsigned* const_iterator;
55 const unsigned RegSize, Alignment; // Size & Alignment of register in bytes
56 const iterator RegsBegin, RegsEnd;
58 TargetRegisterClass(unsigned RS, unsigned Al, iterator RB, iterator RE)
59 : RegSize(RS), Alignment(Al), RegsBegin(RB), RegsEnd(RE) {}
60 virtual ~TargetRegisterClass() {} // Allow subclasses
62 // begin/end - Return all of the registers in this class.
63 iterator begin() const { return RegsBegin; }
64 iterator end() const { return RegsEnd; }
66 // getNumRegs - Return the number of registers in this class
67 unsigned getNumRegs() const { return RegsEnd-RegsBegin; }
69 // getRegister - Return the specified register in the class
70 unsigned getRegister(unsigned i) const {
71 assert(i < getNumRegs() && "Register number out of range!");
75 /// allocation_order_begin/end - These methods define a range of registers
76 /// which specify the registers in this class that are valid to register
77 /// allocate, and the preferred order to allocate them in. For example,
78 /// callee saved registers should be at the end of the list, because it is
79 /// cheaper to allocate caller saved registers.
81 /// These methods take a MachineFunction argument, which can be used to tune
82 /// the allocatable registers based on the characteristics of the function.
83 /// One simple example is that the frame pointer register can be used if
84 /// frame-pointer-elimination is performed.
86 /// By default, these methods return all registers in the class.
88 virtual iterator allocation_order_begin(MachineFunction &MF) const {
91 virtual iterator allocation_order_end(MachineFunction &MF) const {
97 /// getSize - Return the size of the register in bytes, which is also the size
98 /// of a stack slot allocated to hold a spilled copy of this register.
99 unsigned getSize() const { return RegSize; }
101 /// getAlignment - Return the minimum required alignment for a register of
103 unsigned getAlignment() const { return Alignment; }
107 /// MRegisterInfo base class - We assume that the target defines a static array
108 /// of MRegisterDesc objects that represent all of the machine registers that
109 /// the target has. As such, we simply have to track a pointer to this array so
110 /// that we can turn register number into a register descriptor.
112 class MRegisterInfo {
114 typedef const TargetRegisterClass * const * regclass_iterator;
116 const MRegisterDesc *Desc; // Pointer to the descriptor array
117 unsigned NumRegs; // Number of entries in the array
119 regclass_iterator RegClassBegin, RegClassEnd; // List of regclasses
121 const TargetRegisterClass **PhysRegClasses; // Reg class for each register
122 int CallFrameSetupOpcode, CallFrameDestroyOpcode;
124 MRegisterInfo(const MRegisterDesc *D, unsigned NR,
125 regclass_iterator RegClassBegin, regclass_iterator RegClassEnd,
126 int CallFrameSetupOpcode = -1, int CallFrameDestroyOpcode = -1);
127 virtual ~MRegisterInfo();
130 enum { // Define some target independant constants
131 /// NoRegister - This 'hard' register is a 'noop' register for all backends.
132 /// This is used as the destination register for instructions that do not
133 /// produce a value. Some frontends may use this as an operand register to
134 /// mean special things, for example, the Sparc backend uses R0 to mean %g0
135 /// which always PRODUCES the value 0. The X86 backend does not use this
136 /// value as an operand register, except for memory references.
140 /// FirstVirtualRegister - This is the first register number that is
141 /// considered to be a 'virtual' register, which is part of the SSA
142 /// namespace. This must be the same for all targets, which means that each
143 /// target is limited to 1024 registers.
145 FirstVirtualRegister = 1024,
148 const MRegisterDesc &operator[](unsigned RegNo) const {
149 assert(RegNo < NumRegs &&
150 "Attempting to access record for invalid register number!");
154 /// Provide a get method, equivalent to [], but more useful if we have a
155 /// pointer to this object.
157 const MRegisterDesc &get(unsigned RegNo) const { return operator[](RegNo); }
159 /// getRegClass - Return the register class for the specified physical
162 const TargetRegisterClass *getRegClass(unsigned RegNo) const {
163 assert(RegNo < NumRegs && "Register number out of range!");
164 assert(PhysRegClasses[RegNo] && "Register is not in a class!");
165 return PhysRegClasses[RegNo];
168 /// getAliasSet - Return the set of registers aliased by the specified
169 /// register, or a null list of there are none. The list returned is zero
172 const unsigned *getAliasSet(unsigned RegNo) const {
173 return get(RegNo).AliasSet;
176 /// getName - Return the symbolic target specific name for the specified
177 /// physical register.
178 const char *getName(unsigned RegNo) const {
179 return get(RegNo).Name;
182 virtual const unsigned* getCalleeSaveRegs() const = 0;
185 //===--------------------------------------------------------------------===//
186 // Register Class Information
189 /// Register class iterators
190 regclass_iterator regclass_begin() const { return RegClassBegin; }
191 regclass_iterator regclass_end() const { return RegClassEnd; }
193 unsigned getNumRegClasses() const {
194 return regclass_end()-regclass_begin();
196 virtual const TargetRegisterClass* getRegClassForType(const Type* Ty) const=0;
199 //===--------------------------------------------------------------------===//
200 // Interfaces used by the register allocator and stack frame manipulation
201 // passes to move data around between registers, immediates and memory.
204 virtual void storeRegToStackSlot(MachineBasicBlock &MBB,
205 MachineBasicBlock::iterator &MBBI,
206 unsigned SrcReg, int FrameIndex,
207 const TargetRegisterClass *RC) const = 0;
209 virtual void loadRegFromStackSlot(MachineBasicBlock &MBB,
210 MachineBasicBlock::iterator &MBBI,
211 unsigned DestReg, int FrameIndex,
212 const TargetRegisterClass *RC) const = 0;
214 virtual void copyRegToReg(MachineBasicBlock &MBB,
215 MachineBasicBlock::iterator &MBBI,
216 unsigned DestReg, unsigned SrcReg,
217 const TargetRegisterClass *RC) const = 0;
220 /// getCallFrameSetup/DestroyOpcode - These methods return the opcode of the
221 /// frame setup/destroy instructions if they exist (-1 otherwise). Some
222 /// targets use pseudo instructions in order to abstract away the difference
223 /// between operating with a frame pointer and operating without, through the
224 /// use of these two instructions.
226 int getCallFrameSetupOpcode() const { return CallFrameSetupOpcode; }
227 int getCallFrameDestroyOpcode() const { return CallFrameDestroyOpcode; }
230 /// eliminateCallFramePseudoInstr - This method is called during prolog/epilog
231 /// code insertion to eliminate call frame setup and destroy pseudo
232 /// instructions (but only if the Target is using them). It is responsible
233 /// for eliminating these instructions, replacing them with concrete
234 /// instructions. This method need only be implemented if using call frame
235 /// setup/destroy pseudo instructions.
237 virtual void eliminateCallFramePseudoInstr(MachineFunction &MF,
238 MachineBasicBlock &MBB,
239 MachineBasicBlock::iterator &I) const {
240 assert(getCallFrameSetupOpcode()== -1 && getCallFrameDestroyOpcode()== -1 &&
241 "eliminateCallFramePseudoInstr must be implemented if using"
242 " call frame setup/destroy pseudo instructions!");
243 assert(0 && "Call Frame Pseudo Instructions do not exist on this target!");
246 /// processFunctionBeforeFrameFinalized - This method is called immediately
247 /// before the specified functions frame layout (MF.getFrameInfo()) is
248 /// finalized. Once the frame is finalized, MO_FrameIndex operands are
249 /// replaced with direct constants. This method is optional.
251 virtual void processFunctionBeforeFrameFinalized(MachineFunction &MF) const {}
253 /// eliminateFrameIndex - This method must be overriden to eliminate abstract
254 /// frame indices from instructions which may use them. The instruction
255 /// referenced by the iterator contains an MO_FrameIndex operand which must be
256 /// eliminated by this method. This method may modify or replace the
257 /// specified instruction, as long as it keeps the iterator pointing the the
258 /// finished product.
260 virtual void eliminateFrameIndex(MachineFunction &MF,
261 MachineBasicBlock::iterator &II) const = 0;
263 /// emitProlog/emitEpilog - These methods insert prolog and epilog code into
265 virtual void emitPrologue(MachineFunction &MF) const = 0;
266 virtual void emitEpilogue(MachineFunction &MF,
267 MachineBasicBlock &MBB) const = 0;