1 //===-- llvm/CodeGen/MachineRegisterInfo.h ----------------------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file defines the MachineRegisterInfo class.
12 //===----------------------------------------------------------------------===//
14 #ifndef LLVM_CODEGEN_MACHINEREGISTERINFO_H
15 #define LLVM_CODEGEN_MACHINEREGISTERINFO_H
17 #include "llvm/Target/TargetRegisterInfo.h"
18 #include "llvm/ADT/BitVector.h"
19 #include "llvm/ADT/iterator.h"
24 /// MachineRegisterInfo - Keep track of information for virtual and physical
25 /// registers, including vreg register classes, use/def chains for registers,
27 class MachineRegisterInfo {
29 /// Register allocation hints.
30 enum RegAllocHintType {
31 RA_None, /// No preference
32 RA_Preference, /// Prefer a particular register
33 RA_PairEven, /// Even register of a register pair
34 RA_PairOdd /// Odd register of a register pair
38 /// VRegInfo - Information we keep for each virtual register. The entries in
39 /// this vector are actually converted to vreg numbers by adding the
40 /// TargetRegisterInfo::FirstVirtualRegister delta to their index.
42 /// Each element in this list contains the register class of the vreg and the
43 /// start of the use/def list for the register.
44 std::vector<std::pair<const TargetRegisterClass*, MachineOperand*> > VRegInfo;
46 /// RegClassVRegMap - This vector acts as a map from TargetRegisterClass to
47 /// virtual registers. For each target register class, it keeps a list of
48 /// virtual registers belonging to the class.
49 std::vector<std::vector<unsigned> > RegClass2VRegMap;
51 /// RegAllocHints - This vector records register allocation hints for virtual
52 /// registers. For each virtual register, it keeps a register and type enum
53 /// pair making up the allocation hint. For example, if the hint type is
54 /// RA_Specified, it means the virtual register prefers the specified physical
55 /// register of the hint or the physical register allocated to the virtual
56 /// register of the hint.
57 std::vector<std::pair<RegAllocHintType, unsigned> > RegAllocHints;
59 /// PhysRegUseDefLists - This is an array of the head of the use/def list for
60 /// physical registers.
61 MachineOperand **PhysRegUseDefLists;
63 /// UsedPhysRegs - This is a bit vector that is computed and set by the
64 /// register allocator, and must be kept up to date by passes that run after
65 /// register allocation (though most don't modify this). This is used
66 /// so that the code generator knows which callee save registers to save and
67 /// for other target specific uses.
68 BitVector UsedPhysRegs;
70 /// LiveIns/LiveOuts - Keep track of the physical registers that are
71 /// livein/liveout of the function. Live in values are typically arguments in
72 /// registers, live out values are typically return values in registers.
73 /// LiveIn values are allowed to have virtual registers associated with them,
74 /// stored in the second element.
75 std::vector<std::pair<unsigned, unsigned> > LiveIns;
76 std::vector<unsigned> LiveOuts;
78 MachineRegisterInfo(const MachineRegisterInfo&); // DO NOT IMPLEMENT
79 void operator=(const MachineRegisterInfo&); // DO NOT IMPLEMENT
81 explicit MachineRegisterInfo(const TargetRegisterInfo &TRI);
82 ~MachineRegisterInfo();
84 //===--------------------------------------------------------------------===//
86 //===--------------------------------------------------------------------===//
88 /// reg_begin/reg_end - Provide iteration support to walk over all definitions
89 /// and uses of a register within the MachineFunction that corresponds to this
90 /// MachineRegisterInfo object.
91 template<bool Uses, bool Defs>
92 class defusechain_iterator;
94 /// reg_iterator/reg_begin/reg_end - Walk all defs and uses of the specified
96 typedef defusechain_iterator<true,true> reg_iterator;
97 reg_iterator reg_begin(unsigned RegNo) const {
98 return reg_iterator(getRegUseDefListHead(RegNo));
100 static reg_iterator reg_end() { return reg_iterator(0); }
102 /// reg_empty - Return true if there are no instructions using or defining the
103 /// specified register (it may be live-in).
104 bool reg_empty(unsigned RegNo) const { return reg_begin(RegNo) == reg_end(); }
106 /// def_iterator/def_begin/def_end - Walk all defs of the specified register.
107 typedef defusechain_iterator<false,true> def_iterator;
108 def_iterator def_begin(unsigned RegNo) const {
109 return def_iterator(getRegUseDefListHead(RegNo));
111 static def_iterator def_end() { return def_iterator(0); }
113 /// def_empty - Return true if there are no instructions defining the
114 /// specified register (it may be live-in).
115 bool def_empty(unsigned RegNo) const { return def_begin(RegNo) == def_end(); }
117 /// use_iterator/use_begin/use_end - Walk all uses of the specified register.
118 typedef defusechain_iterator<true,false> use_iterator;
119 use_iterator use_begin(unsigned RegNo) const {
120 return use_iterator(getRegUseDefListHead(RegNo));
122 static use_iterator use_end() { return use_iterator(0); }
124 /// use_empty - Return true if there are no instructions using the specified
126 bool use_empty(unsigned RegNo) const { return use_begin(RegNo) == use_end(); }
129 /// replaceRegWith - Replace all instances of FromReg with ToReg in the
130 /// machine function. This is like llvm-level X->replaceAllUsesWith(Y),
131 /// except that it also changes any definitions of the register as well.
132 void replaceRegWith(unsigned FromReg, unsigned ToReg);
134 /// getRegUseDefListHead - Return the head pointer for the register use/def
135 /// list for the specified virtual or physical register.
136 MachineOperand *&getRegUseDefListHead(unsigned RegNo) {
137 if (RegNo < TargetRegisterInfo::FirstVirtualRegister)
138 return PhysRegUseDefLists[RegNo];
139 RegNo -= TargetRegisterInfo::FirstVirtualRegister;
140 return VRegInfo[RegNo].second;
143 MachineOperand *getRegUseDefListHead(unsigned RegNo) const {
144 if (RegNo < TargetRegisterInfo::FirstVirtualRegister)
145 return PhysRegUseDefLists[RegNo];
146 RegNo -= TargetRegisterInfo::FirstVirtualRegister;
147 return VRegInfo[RegNo].second;
150 /// getVRegDef - Return the machine instr that defines the specified virtual
151 /// register or null if none is found. This assumes that the code is in SSA
152 /// form, so there should only be one definition.
153 MachineInstr *getVRegDef(unsigned Reg) const;
156 void dumpUses(unsigned RegNo) const;
159 //===--------------------------------------------------------------------===//
160 // Virtual Register Info
161 //===--------------------------------------------------------------------===//
163 /// getRegClass - Return the register class of the specified virtual register.
165 const TargetRegisterClass *getRegClass(unsigned Reg) const {
166 Reg -= TargetRegisterInfo::FirstVirtualRegister;
167 assert(Reg < VRegInfo.size() && "Invalid vreg!");
168 return VRegInfo[Reg].first;
171 /// setRegClass - Set the register class of the specified virtual register.
173 void setRegClass(unsigned Reg, const TargetRegisterClass *RC);
175 /// createVirtualRegister - Create and return a new virtual register in the
176 /// function with the specified register class.
178 unsigned createVirtualRegister(const TargetRegisterClass *RegClass);
180 /// getLastVirtReg - Return the highest currently assigned virtual register.
182 unsigned getLastVirtReg() const {
183 return (unsigned)VRegInfo.size()+TargetRegisterInfo::FirstVirtualRegister-1;
186 /// getRegClassVirtRegs - Return the list of virtual registers of the given
187 /// target register class.
188 std::vector<unsigned> &getRegClassVirtRegs(const TargetRegisterClass *RC) {
189 return RegClass2VRegMap[RC->getID()];
192 /// setRegAllocationHint - Specify a register allocation hint for the
193 /// specified virtual register.
194 void setRegAllocationHint(unsigned Reg,
195 RegAllocHintType Type, unsigned PrefReg) {
196 Reg -= TargetRegisterInfo::FirstVirtualRegister;
197 assert(Reg < VRegInfo.size() && "Invalid vreg!");
198 RegAllocHints[Reg].first = Type;
199 RegAllocHints[Reg].second = PrefReg;
202 /// getRegAllocationHint - Return the register allocation hint for the
203 /// specified virtual register.
204 std::pair<RegAllocHintType, unsigned>
205 getRegAllocationHint(unsigned Reg) const {
206 Reg -= TargetRegisterInfo::FirstVirtualRegister;
207 assert(Reg < VRegInfo.size() && "Invalid vreg!");
208 return RegAllocHints[Reg];
211 //===--------------------------------------------------------------------===//
212 // Physical Register Use Info
213 //===--------------------------------------------------------------------===//
215 /// isPhysRegUsed - Return true if the specified register is used in this
216 /// function. This only works after register allocation.
217 bool isPhysRegUsed(unsigned Reg) const { return UsedPhysRegs[Reg]; }
219 /// setPhysRegUsed - Mark the specified register used in this function.
220 /// This should only be called during and after register allocation.
221 void setPhysRegUsed(unsigned Reg) { UsedPhysRegs[Reg] = true; }
223 /// setPhysRegUnused - Mark the specified register unused in this function.
224 /// This should only be called during and after register allocation.
225 void setPhysRegUnused(unsigned Reg) { UsedPhysRegs[Reg] = false; }
228 //===--------------------------------------------------------------------===//
229 // LiveIn/LiveOut Management
230 //===--------------------------------------------------------------------===//
232 /// addLiveIn/Out - Add the specified register as a live in/out. Note that it
233 /// is an error to add the same register to the same set more than once.
234 void addLiveIn(unsigned Reg, unsigned vreg = 0) {
235 LiveIns.push_back(std::make_pair(Reg, vreg));
237 void addLiveOut(unsigned Reg) { LiveOuts.push_back(Reg); }
239 // Iteration support for live in/out sets. These sets are kept in sorted
240 // order by their register number.
241 typedef std::vector<std::pair<unsigned,unsigned> >::const_iterator
243 typedef std::vector<unsigned>::const_iterator liveout_iterator;
244 livein_iterator livein_begin() const { return LiveIns.begin(); }
245 livein_iterator livein_end() const { return LiveIns.end(); }
246 bool livein_empty() const { return LiveIns.empty(); }
247 liveout_iterator liveout_begin() const { return LiveOuts.begin(); }
248 liveout_iterator liveout_end() const { return LiveOuts.end(); }
249 bool liveout_empty() const { return LiveOuts.empty(); }
251 bool isLiveIn(unsigned Reg) const {
252 for (livein_iterator I = livein_begin(), E = livein_end(); I != E; ++I)
253 if (I->first == Reg || I->second == Reg)
259 void HandleVRegListReallocation();
262 /// defusechain_iterator - This class provides iterator support for machine
263 /// operands in the function that use or define a specific register. If
264 /// ReturnUses is true it returns uses of registers, if ReturnDefs is true it
265 /// returns defs. If neither are true then you are silly and it always
267 template<bool ReturnUses, bool ReturnDefs>
268 class defusechain_iterator
269 : public forward_iterator<MachineInstr, ptrdiff_t> {
271 explicit defusechain_iterator(MachineOperand *op) : Op(op) {
272 // If the first node isn't one we're interested in, advance to one that
273 // we are interested in.
275 if ((!ReturnUses && op->isUse()) ||
276 (!ReturnDefs && op->isDef()))
280 friend class MachineRegisterInfo;
282 typedef forward_iterator<MachineInstr, ptrdiff_t>::reference reference;
283 typedef forward_iterator<MachineInstr, ptrdiff_t>::pointer pointer;
285 defusechain_iterator(const defusechain_iterator &I) : Op(I.Op) {}
286 defusechain_iterator() : Op(0) {}
288 bool operator==(const defusechain_iterator &x) const {
291 bool operator!=(const defusechain_iterator &x) const {
292 return !operator==(x);
295 /// atEnd - return true if this iterator is equal to reg_end() on the value.
296 bool atEnd() const { return Op == 0; }
298 // Iterator traversal: forward iteration only
299 defusechain_iterator &operator++() { // Preincrement
300 assert(Op && "Cannot increment end iterator!");
301 Op = Op->getNextOperandForReg();
303 // If this is an operand we don't care about, skip it.
304 while (Op && ((!ReturnUses && Op->isUse()) ||
305 (!ReturnDefs && Op->isDef())))
306 Op = Op->getNextOperandForReg();
310 defusechain_iterator operator++(int) { // Postincrement
311 defusechain_iterator tmp = *this; ++*this; return tmp;
314 MachineOperand &getOperand() const {
315 assert(Op && "Cannot dereference end iterator!");
319 /// getOperandNo - Return the operand # of this MachineOperand in its
321 unsigned getOperandNo() const {
322 assert(Op && "Cannot dereference end iterator!");
323 return Op - &Op->getParent()->getOperand(0);
326 // Retrieve a reference to the current operand.
327 MachineInstr &operator*() const {
328 assert(Op && "Cannot dereference end iterator!");
329 return *Op->getParent();
332 MachineInstr *operator->() const {
333 assert(Op && "Cannot dereference end iterator!");
334 return Op->getParent();
340 } // End llvm namespace