1 //===-- llvm/CodeGen/VirtRegMap.h - Virtual Register Map -*- C++ -*--------===//
3 // The LLVM Compiler Infrastructure
5 // This file was developed by the LLVM research group and is distributed under
6 // the University of Illinois Open Source License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file implements a virtual register map. This maps virtual registers to
11 // physical registers and virtual registers to stack slots. It is created and
12 // updated by a register allocator and then used by a machine code rewriter that
13 // adds spill code and rewrites virtual into physical register references.
15 //===----------------------------------------------------------------------===//
17 #ifndef LLVM_CODEGEN_VIRTREGMAP_H
18 #define LLVM_CODEGEN_VIRTREGMAP_H
20 #include "llvm/Target/MRegisterInfo.h"
21 #include "llvm/ADT/DenseMap.h"
22 #include "llvm/ADT/IndexedMap.h"
23 #include "llvm/Support/Streams.h"
28 class MachineFunction;
29 class TargetInstrInfo;
35 NO_STACK_SLOT = (1L << 30)-1,
36 MAX_STACK_SLOT = (1L << 18)-1
39 enum ModRef { isRef = 1, isMod = 2, isModRef = 3 };
40 typedef std::multimap<MachineInstr*,
41 std::pair<unsigned, ModRef> > MI2VirtMapTy;
44 const TargetInstrInfo &TII;
47 /// Virt2PhysMap - This is a virtual to physical register
48 /// mapping. Each virtual register is required to have an entry in
49 /// it; even spilled virtual registers (the register mapped to a
50 /// spilled register is the temporary used to load it from the
52 IndexedMap<unsigned, VirtReg2IndexFunctor> Virt2PhysMap;
54 /// Virt2StackSlotMap - This is virtual register to stack slot
55 /// mapping. Each spilled virtual register has an entry in it
56 /// which corresponds to the stack slot this register is spilled
58 IndexedMap<int, VirtReg2IndexFunctor> Virt2StackSlotMap;
60 /// Virt2StackSlotMap - This is virtual register to rematerialization id
61 /// mapping. Each spilled virtual register that should be remat'd has an
62 /// entry in it which corresponds to the remat id.
63 IndexedMap<int, VirtReg2IndexFunctor> Virt2ReMatIdMap;
65 /// Virt2SplitMap - This is virtual register to splitted virtual register
67 IndexedMap<unsigned, VirtReg2IndexFunctor> Virt2SplitMap;
69 /// ReMatMap - This is virtual register to re-materialized instruction
70 /// mapping. Each virtual register whose definition is going to be
71 /// re-materialized has an entry in it.
72 IndexedMap<MachineInstr*, VirtReg2IndexFunctor> ReMatMap;
74 /// MI2VirtMap - This is MachineInstr to virtual register
75 /// mapping. In the case of memory spill code being folded into
76 /// instructions, we need to know which virtual register was
77 /// read/written by this instruction.
78 MI2VirtMapTy MI2VirtMap;
80 /// SpillPt2VirtMap - This records the virtual registers which should
81 /// be spilled right after the MachineInstr due to live interval
83 std::map<MachineInstr*, std::vector<unsigned> > SpillPt2VirtMap;
85 /// ReMatId - Instead of assigning a stack slot to a to be rematerialized
86 /// virtual register, an unique id is being assigned. This keeps track of
87 /// the highest id used so far. Note, this starts at (1<<18) to avoid
88 /// conflicts with stack slot numbers.
91 VirtRegMap(const VirtRegMap&); // DO NOT IMPLEMENT
92 void operator=(const VirtRegMap&); // DO NOT IMPLEMENT
95 explicit VirtRegMap(MachineFunction &mf);
99 /// @brief returns true if the specified virtual register is
100 /// mapped to a physical register
101 bool hasPhys(unsigned virtReg) const {
102 return getPhys(virtReg) != NO_PHYS_REG;
105 /// @brief returns the physical register mapped to the specified
107 unsigned getPhys(unsigned virtReg) const {
108 assert(MRegisterInfo::isVirtualRegister(virtReg));
109 return Virt2PhysMap[virtReg];
112 /// @brief creates a mapping for the specified virtual register to
113 /// the specified physical register
114 void assignVirt2Phys(unsigned virtReg, unsigned physReg) {
115 assert(MRegisterInfo::isVirtualRegister(virtReg) &&
116 MRegisterInfo::isPhysicalRegister(physReg));
117 assert(Virt2PhysMap[virtReg] == NO_PHYS_REG &&
118 "attempt to assign physical register to already mapped "
120 Virt2PhysMap[virtReg] = physReg;
123 /// @brief clears the specified virtual register's, physical
125 void clearVirt(unsigned virtReg) {
126 assert(MRegisterInfo::isVirtualRegister(virtReg));
127 assert(Virt2PhysMap[virtReg] != NO_PHYS_REG &&
128 "attempt to clear a not assigned virtual register");
129 Virt2PhysMap[virtReg] = NO_PHYS_REG;
132 /// @brief clears all virtual to physical register mappings
133 void clearAllVirt() {
134 Virt2PhysMap.clear();
138 /// @brief records virtReg is a split live interval from SReg.
139 void setIsSplitFromReg(unsigned virtReg, unsigned SReg) {
140 Virt2SplitMap[virtReg] = SReg;
143 /// @brief returns the live interval virtReg is split from.
144 unsigned getPreSplitReg(unsigned virtReg) {
145 return Virt2SplitMap[virtReg];
148 /// @brief returns true is the specified virtual register is not
149 /// mapped to a stack slot or rematerialized.
150 bool isAssignedReg(unsigned virtReg) const {
151 if (getStackSlot(virtReg) == NO_STACK_SLOT &&
152 getReMatId(virtReg) == NO_STACK_SLOT)
154 // Split register can be assigned a physical register as well as a
155 // stack slot or remat id.
156 return (Virt2SplitMap[virtReg] && Virt2PhysMap[virtReg] != NO_PHYS_REG);
159 /// @brief returns the stack slot mapped to the specified virtual
161 int getStackSlot(unsigned virtReg) const {
162 assert(MRegisterInfo::isVirtualRegister(virtReg));
163 return Virt2StackSlotMap[virtReg];
166 /// @brief returns the rematerialization id mapped to the specified virtual
168 int getReMatId(unsigned virtReg) const {
169 assert(MRegisterInfo::isVirtualRegister(virtReg));
170 return Virt2ReMatIdMap[virtReg];
173 /// @brief create a mapping for the specifed virtual register to
174 /// the next available stack slot
175 int assignVirt2StackSlot(unsigned virtReg);
176 /// @brief create a mapping for the specified virtual register to
177 /// the specified stack slot
178 void assignVirt2StackSlot(unsigned virtReg, int frameIndex);
180 /// @brief assign an unique re-materialization id to the specified
181 /// virtual register.
182 int assignVirtReMatId(unsigned virtReg);
183 /// @brief assign an unique re-materialization id to the specified
184 /// virtual register.
185 void assignVirtReMatId(unsigned virtReg, int id);
187 /// @brief returns true if the specified virtual register is being
189 bool isReMaterialized(unsigned virtReg) const {
190 return ReMatMap[virtReg] != NULL;
193 /// @brief returns the original machine instruction being re-issued
194 /// to re-materialize the specified virtual register.
195 MachineInstr *getReMaterializedMI(unsigned virtReg) const {
196 return ReMatMap[virtReg];
199 /// @brief records the specified virtual register will be
200 /// re-materialized and the original instruction which will be re-issed
201 /// for this purpose. If parameter all is true, then all uses of the
202 /// registers are rematerialized and it's safe to delete the definition.
203 void setVirtIsReMaterialized(unsigned virtReg, MachineInstr *def) {
204 ReMatMap[virtReg] = def;
207 /// @brief returns true if the specified MachineInstr is a spill point.
208 bool isSpillPt(MachineInstr *Pt) const {
209 return SpillPt2VirtMap.find(Pt) != SpillPt2VirtMap.end();
212 /// @brief returns the virtual registers that should be spilled due to
213 /// splitting right after the specified MachineInstr.
214 std::vector<unsigned> &getSpillPtSpills(MachineInstr *Pt) {
215 return SpillPt2VirtMap[Pt];
218 /// @brief records the specified MachineInstr as a spill point for virtReg.
219 void addSpillPoint(unsigned virtReg, MachineInstr *Pt) {
220 if (SpillPt2VirtMap.find(Pt) != SpillPt2VirtMap.end())
221 SpillPt2VirtMap[Pt].push_back(virtReg);
223 std::vector<unsigned> Virts;
224 Virts.push_back(virtReg);
225 SpillPt2VirtMap.insert(std::make_pair(Pt, Virts));
229 void transferSpillPts(MachineInstr *Old, MachineInstr *New) {
230 std::map<MachineInstr*,std::vector<unsigned> >::iterator I =
231 SpillPt2VirtMap.find(Old);
232 if (I == SpillPt2VirtMap.end())
234 while (!I->second.empty()) {
235 unsigned virtReg = I->second.back();
236 I->second.pop_back();
237 addSpillPoint(virtReg, New);
239 SpillPt2VirtMap.erase(I);
242 /// @brief Updates information about the specified virtual register's value
243 /// folded into newMI machine instruction. The OpNum argument indicates the
244 /// operand number of OldMI that is folded.
245 void virtFolded(unsigned VirtReg, MachineInstr *OldMI, unsigned OpNum,
246 MachineInstr *NewMI);
248 /// @brief Updates information about the specified virtual register's value
249 /// folded into the specified machine instruction.
250 void virtFolded(unsigned VirtReg, MachineInstr *MI, ModRef MRInfo);
252 /// @brief returns the virtual registers' values folded in memory
253 /// operands of this instruction
254 std::pair<MI2VirtMapTy::const_iterator, MI2VirtMapTy::const_iterator>
255 getFoldedVirts(MachineInstr* MI) const {
256 return MI2VirtMap.equal_range(MI);
259 /// RemoveMachineInstrFromMaps - MI is being erased, remove it from the
260 /// the folded instruction map and spill point map.
261 void RemoveMachineInstrFromMaps(MachineInstr *MI) {
262 MI2VirtMap.erase(MI);
263 SpillPt2VirtMap.erase(MI);
266 void print(std::ostream &OS) const;
267 void print(std::ostream *OS) const { if (OS) print(*OS); }
271 inline std::ostream *operator<<(std::ostream *OS, const VirtRegMap &VRM) {
275 inline std::ostream &operator<<(std::ostream &OS, const VirtRegMap &VRM) {
280 /// Spiller interface: Implementations of this interface assign spilled
281 /// virtual registers to stack slots, rewriting the code.
284 virtual bool runOnMachineFunction(MachineFunction &MF,
285 VirtRegMap &VRM) = 0;
288 /// createSpiller - Create an return a spiller object, as specified on the
290 Spiller* createSpiller();
292 } // End llvm namespace