1 //===-- HexagonRegisterInfo.cpp - Hexagon Register Information ------------===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // This file contains the Hexagon implementation of the TargetRegisterInfo
11 // class.
12 //
13 //===----------------------------------------------------------------------===//
14
15 #include "HexagonRegisterInfo.h"
16 #include "Hexagon.h"
17 #include "HexagonMachineFunctionInfo.h"
18 #include "HexagonSubtarget.h"
19 #include "HexagonTargetMachine.h"
20 #include "llvm/ADT/BitVector.h"
21 #include "llvm/ADT/STLExtras.h"
22 #include "llvm/CodeGen/LiveIntervals.h"
23 #include "llvm/CodeGen/MachineFrameInfo.h"
24 #include "llvm/CodeGen/MachineFunction.h"
25 #include "llvm/CodeGen/MachineFunctionPass.h"
26 #include "llvm/CodeGen/MachineInstrBuilder.h"
27 #include "llvm/CodeGen/MachineRegisterInfo.h"
28 #include "llvm/CodeGen/PseudoSourceValue.h"
29 #include "llvm/CodeGen/RegisterScavenging.h"
30 #include "llvm/CodeGen/TargetInstrInfo.h"
31 #include "llvm/IR/Function.h"
32 #include "llvm/IR/Type.h"
33 #include "llvm/MC/MachineLocation.h"
34 #include "llvm/Support/Debug.h"
35 #include "llvm/Support/ErrorHandling.h"
36 #include "llvm/Support/raw_ostream.h"
37 #include "llvm/Target/TargetMachine.h"
38 #include "llvm/Target/TargetOptions.h"
39
40 #define GET_REGINFO_TARGET_DESC
41 #include "HexagonGenRegisterInfo.inc"
42
43 using namespace llvm;
44
HexagonRegisterInfo(unsigned HwMode)45 HexagonRegisterInfo::HexagonRegisterInfo(unsigned HwMode)
46 : HexagonGenRegisterInfo(Hexagon::R31, 0/*DwarfFlavor*/, 0/*EHFlavor*/,
47 0/*PC*/, HwMode) {}
48
49
isEHReturnCalleeSaveReg(unsigned R) const50 bool HexagonRegisterInfo::isEHReturnCalleeSaveReg(unsigned R) const {
51 return R == Hexagon::R0 || R == Hexagon::R1 || R == Hexagon::R2 ||
52 R == Hexagon::R3 || R == Hexagon::D0 || R == Hexagon::D1;
53 }
54
55 const MCPhysReg *
getCallerSavedRegs(const MachineFunction * MF,const TargetRegisterClass * RC) const56 HexagonRegisterInfo::getCallerSavedRegs(const MachineFunction *MF,
57 const TargetRegisterClass *RC) const {
58 using namespace Hexagon;
59
60 static const MCPhysReg Int32[] = {
61 R0, R1, R2, R3, R4, R5, R6, R7, R8, R9, R10, R11, R12, R13, R14, R15, 0
62 };
63 static const MCPhysReg Int64[] = {
64 D0, D1, D2, D3, D4, D5, D6, D7, 0
65 };
66 static const MCPhysReg Pred[] = {
67 P0, P1, P2, P3, 0
68 };
69 static const MCPhysReg VecSgl[] = {
70 V0, V1, V2, V3, V4, V5, V6, V7, V8, V9, V10, V11, V12, V13,
71 V14, V15, V16, V17, V18, V19, V20, V21, V22, V23, V24, V25, V26, V27,
72 V28, V29, V30, V31, 0
73 };
74 static const MCPhysReg VecDbl[] = {
75 W0, W1, W2, W3, W4, W5, W6, W7, W8, W9, W10, W11, W12, W13, W14, W15, 0
76 };
77
78 switch (RC->getID()) {
79 case IntRegsRegClassID:
80 return Int32;
81 case DoubleRegsRegClassID:
82 return Int64;
83 case PredRegsRegClassID:
84 return Pred;
85 case HvxVRRegClassID:
86 return VecSgl;
87 case HvxWRRegClassID:
88 return VecDbl;
89 default:
90 break;
91 }
92
93 static const MCPhysReg Empty[] = { 0 };
94 #ifndef NDEBUG
95 dbgs() << "Register class: " << getRegClassName(RC) << "\n";
96 #endif
97 llvm_unreachable("Unexpected register class");
98 return Empty;
99 }
100
101
102 const MCPhysReg *
getCalleeSavedRegs(const MachineFunction * MF) const103 HexagonRegisterInfo::getCalleeSavedRegs(const MachineFunction *MF) const {
104 static const MCPhysReg CalleeSavedRegsV3[] = {
105 Hexagon::R16, Hexagon::R17, Hexagon::R18, Hexagon::R19,
106 Hexagon::R20, Hexagon::R21, Hexagon::R22, Hexagon::R23,
107 Hexagon::R24, Hexagon::R25, Hexagon::R26, Hexagon::R27, 0
108 };
109
110 // Functions that contain a call to __builtin_eh_return also save the first 4
111 // parameter registers.
112 static const MCPhysReg CalleeSavedRegsV3EHReturn[] = {
113 Hexagon::R0, Hexagon::R1, Hexagon::R2, Hexagon::R3,
114 Hexagon::R16, Hexagon::R17, Hexagon::R18, Hexagon::R19,
115 Hexagon::R20, Hexagon::R21, Hexagon::R22, Hexagon::R23,
116 Hexagon::R24, Hexagon::R25, Hexagon::R26, Hexagon::R27, 0
117 };
118
119 bool HasEHReturn = MF->getInfo<HexagonMachineFunctionInfo>()->hasEHReturn();
120
121 return HasEHReturn ? CalleeSavedRegsV3EHReturn : CalleeSavedRegsV3;
122 }
123
124
getCallPreservedMask(const MachineFunction & MF,CallingConv::ID) const125 const uint32_t *HexagonRegisterInfo::getCallPreservedMask(
126 const MachineFunction &MF, CallingConv::ID) const {
127 return HexagonCSR_RegMask;
128 }
129
130
getReservedRegs(const MachineFunction & MF) const131 BitVector HexagonRegisterInfo::getReservedRegs(const MachineFunction &MF)
132 const {
133 BitVector Reserved(getNumRegs());
134 Reserved.set(Hexagon::R29);
135 Reserved.set(Hexagon::R30);
136 Reserved.set(Hexagon::R31);
137 Reserved.set(Hexagon::VTMP);
138
139 // Guest registers.
140 Reserved.set(Hexagon::GELR); // G0
141 Reserved.set(Hexagon::GSR); // G1
142 Reserved.set(Hexagon::GOSP); // G2
143 Reserved.set(Hexagon::G3); // G3
144
145 // Control registers.
146 Reserved.set(Hexagon::SA0); // C0
147 Reserved.set(Hexagon::LC0); // C1
148 Reserved.set(Hexagon::SA1); // C2
149 Reserved.set(Hexagon::LC1); // C3
150 Reserved.set(Hexagon::P3_0); // C4
151 Reserved.set(Hexagon::USR); // C8
152 Reserved.set(Hexagon::PC); // C9
153 Reserved.set(Hexagon::UGP); // C10
154 Reserved.set(Hexagon::GP); // C11
155 Reserved.set(Hexagon::CS0); // C12
156 Reserved.set(Hexagon::CS1); // C13
157 Reserved.set(Hexagon::UPCYCLELO); // C14
158 Reserved.set(Hexagon::UPCYCLEHI); // C15
159 Reserved.set(Hexagon::FRAMELIMIT); // C16
160 Reserved.set(Hexagon::FRAMEKEY); // C17
161 Reserved.set(Hexagon::PKTCOUNTLO); // C18
162 Reserved.set(Hexagon::PKTCOUNTHI); // C19
163 Reserved.set(Hexagon::UTIMERLO); // C30
164 Reserved.set(Hexagon::UTIMERHI); // C31
165 // Out of the control registers, only C8 is explicitly defined in
166 // HexagonRegisterInfo.td. If others are defined, make sure to add
167 // them here as well.
168 Reserved.set(Hexagon::C8);
169 Reserved.set(Hexagon::USR_OVF);
170
171 if (MF.getSubtarget<HexagonSubtarget>().hasReservedR19())
172 Reserved.set(Hexagon::R19);
173
174 for (int x = Reserved.find_first(); x >= 0; x = Reserved.find_next(x))
175 markSuperRegs(Reserved, x);
176
177 return Reserved;
178 }
179
180
eliminateFrameIndex(MachineBasicBlock::iterator II,int SPAdj,unsigned FIOp,RegScavenger * RS) const181 void HexagonRegisterInfo::eliminateFrameIndex(MachineBasicBlock::iterator II,
182 int SPAdj, unsigned FIOp,
183 RegScavenger *RS) const {
184 //
185 // Hexagon_TODO: Do we need to enforce this for Hexagon?
186 assert(SPAdj == 0 && "Unexpected");
187
188 MachineInstr &MI = *II;
189 MachineBasicBlock &MB = *MI.getParent();
190 MachineFunction &MF = *MB.getParent();
191 auto &HST = MF.getSubtarget<HexagonSubtarget>();
192 auto &HII = *HST.getInstrInfo();
193 auto &HFI = *HST.getFrameLowering();
194
195 unsigned BP = 0;
196 int FI = MI.getOperand(FIOp).getIndex();
197 // Select the base pointer (BP) and calculate the actual offset from BP
198 // to the beginning of the object at index FI.
199 int Offset = HFI.getFrameIndexReference(MF, FI, BP);
200 // Add the offset from the instruction.
201 int RealOffset = Offset + MI.getOperand(FIOp+1).getImm();
202 bool IsKill = false;
203
204 unsigned Opc = MI.getOpcode();
205 switch (Opc) {
206 case Hexagon::PS_fia:
207 MI.setDesc(HII.get(Hexagon::A2_addi));
208 MI.getOperand(FIOp).ChangeToImmediate(RealOffset);
209 MI.RemoveOperand(FIOp+1);
210 return;
211 case Hexagon::PS_fi:
212 // Set up the instruction for updating below.
213 MI.setDesc(HII.get(Hexagon::A2_addi));
214 break;
215 }
216
217 if (!HII.isValidOffset(Opc, RealOffset, this)) {
218 // If the offset is not valid, calculate the address in a temporary
219 // register and use it with offset 0.
220 auto &MRI = MF.getRegInfo();
221 unsigned TmpR = MRI.createVirtualRegister(&Hexagon::IntRegsRegClass);
222 const DebugLoc &DL = MI.getDebugLoc();
223 BuildMI(MB, II, DL, HII.get(Hexagon::A2_addi), TmpR)
224 .addReg(BP)
225 .addImm(RealOffset);
226 BP = TmpR;
227 RealOffset = 0;
228 IsKill = true;
229 }
230
231 MI.getOperand(FIOp).ChangeToRegister(BP, false, false, IsKill);
232 MI.getOperand(FIOp+1).ChangeToImmediate(RealOffset);
233 }
234
235
shouldCoalesce(MachineInstr * MI,const TargetRegisterClass * SrcRC,unsigned SubReg,const TargetRegisterClass * DstRC,unsigned DstSubReg,const TargetRegisterClass * NewRC,LiveIntervals & LIS) const236 bool HexagonRegisterInfo::shouldCoalesce(MachineInstr *MI,
237 const TargetRegisterClass *SrcRC, unsigned SubReg,
238 const TargetRegisterClass *DstRC, unsigned DstSubReg,
239 const TargetRegisterClass *NewRC, LiveIntervals &LIS) const {
240 // Coalescing will extend the live interval of the destination register.
241 // If the destination register is a vector pair, avoid introducing function
242 // calls into the interval, since it could result in a spilling of a pair
243 // instead of a single vector.
244 MachineFunction &MF = *MI->getParent()->getParent();
245 const HexagonSubtarget &HST = MF.getSubtarget<HexagonSubtarget>();
246 if (!HST.useHVXOps() || NewRC->getID() != Hexagon::HvxWRRegClass.getID())
247 return true;
248 bool SmallSrc = SrcRC->getID() == Hexagon::HvxVRRegClass.getID();
249 bool SmallDst = DstRC->getID() == Hexagon::HvxVRRegClass.getID();
250 if (!SmallSrc && !SmallDst)
251 return true;
252
253 unsigned DstReg = MI->getOperand(0).getReg();
254 unsigned SrcReg = MI->getOperand(1).getReg();
255 const SlotIndexes &Indexes = *LIS.getSlotIndexes();
256 auto HasCall = [&Indexes] (const LiveInterval::Segment &S) {
257 for (SlotIndex I = S.start.getBaseIndex(), E = S.end.getBaseIndex();
258 I != E; I = I.getNextIndex()) {
259 if (const MachineInstr *MI = Indexes.getInstructionFromIndex(I))
260 if (MI->isCall())
261 return true;
262 }
263 return false;
264 };
265
266 if (SmallSrc == SmallDst) {
267 // Both must be true, because the case for both being false was
268 // checked earlier. Both registers will be coalesced into a register
269 // of a wider class (HvxWR), and we don't want its live range to
270 // span over calls.
271 return !any_of(LIS.getInterval(DstReg), HasCall) &&
272 !any_of(LIS.getInterval(SrcReg), HasCall);
273 }
274
275 // If one register is large (HvxWR) and the other is small (HvxVR), then
276 // coalescing is ok if the large is already live across a function call,
277 // or if the small one is not.
278 unsigned SmallReg = SmallSrc ? SrcReg : DstReg;
279 unsigned LargeReg = SmallSrc ? DstReg : SrcReg;
280 return any_of(LIS.getInterval(LargeReg), HasCall) ||
281 !any_of(LIS.getInterval(SmallReg), HasCall);
282 }
283
284
getRARegister() const285 unsigned HexagonRegisterInfo::getRARegister() const {
286 return Hexagon::R31;
287 }
288
289
getFrameRegister(const MachineFunction & MF) const290 unsigned HexagonRegisterInfo::getFrameRegister(const MachineFunction
291 &MF) const {
292 const HexagonFrameLowering *TFI = getFrameLowering(MF);
293 if (TFI->hasFP(MF))
294 return getFrameRegister();
295 return getStackRegister();
296 }
297
298
getFrameRegister() const299 unsigned HexagonRegisterInfo::getFrameRegister() const {
300 return Hexagon::R30;
301 }
302
303
getStackRegister() const304 unsigned HexagonRegisterInfo::getStackRegister() const {
305 return Hexagon::R29;
306 }
307
308
getHexagonSubRegIndex(const TargetRegisterClass & RC,unsigned GenIdx) const309 unsigned HexagonRegisterInfo::getHexagonSubRegIndex(
310 const TargetRegisterClass &RC, unsigned GenIdx) const {
311 assert(GenIdx == Hexagon::ps_sub_lo || GenIdx == Hexagon::ps_sub_hi);
312
313 static const unsigned ISub[] = { Hexagon::isub_lo, Hexagon::isub_hi };
314 static const unsigned VSub[] = { Hexagon::vsub_lo, Hexagon::vsub_hi };
315 static const unsigned WSub[] = { Hexagon::wsub_lo, Hexagon::wsub_hi };
316
317 switch (RC.getID()) {
318 case Hexagon::CtrRegs64RegClassID:
319 case Hexagon::DoubleRegsRegClassID:
320 return ISub[GenIdx];
321 case Hexagon::HvxWRRegClassID:
322 return VSub[GenIdx];
323 case Hexagon::HvxVQRRegClassID:
324 return WSub[GenIdx];
325 }
326
327 if (const TargetRegisterClass *SuperRC = *RC.getSuperClasses())
328 return getHexagonSubRegIndex(*SuperRC, GenIdx);
329
330 llvm_unreachable("Invalid register class");
331 }
332
useFPForScavengingIndex(const MachineFunction & MF) const333 bool HexagonRegisterInfo::useFPForScavengingIndex(const MachineFunction &MF)
334 const {
335 return MF.getSubtarget<HexagonSubtarget>().getFrameLowering()->hasFP(MF);
336 }
337
338 const TargetRegisterClass *
getPointerRegClass(const MachineFunction & MF,unsigned Kind) const339 HexagonRegisterInfo::getPointerRegClass(const MachineFunction &MF,
340 unsigned Kind) const {
341 return &Hexagon::IntRegsRegClass;
342 }
343
getFirstCallerSavedNonParamReg() const344 unsigned HexagonRegisterInfo::getFirstCallerSavedNonParamReg() const {
345 return Hexagon::R6;
346 }
347
348