1//===-- AVRInstrInfo.cpp - AVR Instruction Information --------------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// This file contains the AVR implementation of the TargetInstrInfo class.
10//
11//===----------------------------------------------------------------------===//
12
13#include "AVRInstrInfo.h"
14
15#include "llvm/ADT/STLExtras.h"
16#include "llvm/CodeGen/MachineConstantPool.h"
17#include "llvm/CodeGen/MachineFrameInfo.h"
18#include "llvm/CodeGen/MachineInstrBuilder.h"
19#include "llvm/CodeGen/MachineMemOperand.h"
20#include "llvm/IR/Constants.h"
21#include "llvm/IR/Function.h"
22#include "llvm/MC/MCContext.h"
23#include "llvm/MC/TargetRegistry.h"
24#include "llvm/Support/Debug.h"
25#include "llvm/Support/ErrorHandling.h"
26
27#include "AVR.h"
28#include "AVRMachineFunctionInfo.h"
29#include "AVRRegisterInfo.h"
30#include "AVRTargetMachine.h"
31#include "MCTargetDesc/AVRMCTargetDesc.h"
32
33#define GET_INSTRINFO_CTOR_DTOR
34#include "AVRGenInstrInfo.inc"
35
36namespace llvm {
37
38AVRInstrInfo::AVRInstrInfo(AVRSubtarget &STI)
39 : AVRGenInstrInfo(AVR::ADJCALLSTACKDOWN, AVR::ADJCALLSTACKUP), RI(),
40 STI(STI) {}
41
42void AVRInstrInfo::copyPhysReg(MachineBasicBlock &MBB,
43 MachineBasicBlock::iterator MI,
44 const DebugLoc &DL, MCRegister DestReg,
45 MCRegister SrcReg, bool KillSrc) const {
46 const AVRRegisterInfo &TRI = *STI.getRegisterInfo();
47 unsigned Opc;
48
49 if (AVR::DREGSRegClass.contains(DestReg, SrcReg)) {
50 // If our AVR has `movw`, let's emit that; otherwise let's emit two separate
51 // `mov`s.
52 if (STI.hasMOVW() && AVR::DREGSMOVWRegClass.contains(DestReg, SrcReg)) {
53 BuildMI(MBB, MI, DL, get(AVR::MOVWRdRr), DestReg)
54 .addReg(SrcReg, getKillRegState(KillSrc));
55 } else {
56 Register DestLo, DestHi, SrcLo, SrcHi;
57
58 TRI.splitReg(Reg: DestReg, LoReg&: DestLo, HiReg&: DestHi);
59 TRI.splitReg(Reg: SrcReg, LoReg&: SrcLo, HiReg&: SrcHi);
60
61 // Emit the copies.
62 // The original instruction was for a register pair, of which only one
63 // register might have been live. Add 'undef' to satisfy the machine
64 // verifier, when subreg liveness is enabled.
65 // TODO: Eliminate these unnecessary copies.
66 if (DestLo == SrcHi) {
67 BuildMI(MBB, MI, DL, get(AVR::MOVRdRr), DestHi)
68 .addReg(SrcHi, getKillRegState(KillSrc) | RegState::Undef);
69 BuildMI(MBB, MI, DL, get(AVR::MOVRdRr), DestLo)
70 .addReg(SrcLo, getKillRegState(KillSrc) | RegState::Undef);
71 } else {
72 BuildMI(MBB, MI, DL, get(AVR::MOVRdRr), DestLo)
73 .addReg(SrcLo, getKillRegState(KillSrc) | RegState::Undef);
74 BuildMI(MBB, MI, DL, get(AVR::MOVRdRr), DestHi)
75 .addReg(SrcHi, getKillRegState(KillSrc) | RegState::Undef);
76 }
77 }
78 } else {
79 if (AVR::GPR8RegClass.contains(DestReg, SrcReg)) {
80 Opc = AVR::MOVRdRr;
81 } else if (SrcReg == AVR::SP && AVR::DREGSRegClass.contains(DestReg)) {
82 Opc = AVR::SPREAD;
83 } else if (DestReg == AVR::SP && AVR::DREGSRegClass.contains(SrcReg)) {
84 Opc = AVR::SPWRITE;
85 } else {
86 llvm_unreachable("Impossible reg-to-reg copy");
87 }
88
89 BuildMI(MBB, MI, DL, get(Opc), DestReg)
90 .addReg(SrcReg, getKillRegState(B: KillSrc));
91 }
92}
93
94Register AVRInstrInfo::isLoadFromStackSlot(const MachineInstr &MI,
95 int &FrameIndex) const {
96 switch (MI.getOpcode()) {
97 case AVR::LDDRdPtrQ:
98 case AVR::LDDWRdYQ: { //: FIXME: remove this once PR13375 gets fixed
99 if (MI.getOperand(i: 1).isFI() && MI.getOperand(i: 2).isImm() &&
100 MI.getOperand(i: 2).getImm() == 0) {
101 FrameIndex = MI.getOperand(i: 1).getIndex();
102 return MI.getOperand(i: 0).getReg();
103 }
104 break;
105 }
106 default:
107 break;
108 }
109
110 return 0;
111}
112
113Register AVRInstrInfo::isStoreToStackSlot(const MachineInstr &MI,
114 int &FrameIndex) const {
115 switch (MI.getOpcode()) {
116 case AVR::STDPtrQRr:
117 case AVR::STDWPtrQRr: {
118 if (MI.getOperand(i: 0).isFI() && MI.getOperand(i: 1).isImm() &&
119 MI.getOperand(i: 1).getImm() == 0) {
120 FrameIndex = MI.getOperand(i: 0).getIndex();
121 return MI.getOperand(i: 2).getReg();
122 }
123 break;
124 }
125 default:
126 break;
127 }
128
129 return 0;
130}
131
132void AVRInstrInfo::storeRegToStackSlot(
133 MachineBasicBlock &MBB, MachineBasicBlock::iterator MI, Register SrcReg,
134 bool isKill, int FrameIndex, const TargetRegisterClass *RC,
135 const TargetRegisterInfo *TRI, Register VReg) const {
136 MachineFunction &MF = *MBB.getParent();
137 AVRMachineFunctionInfo *AFI = MF.getInfo<AVRMachineFunctionInfo>();
138
139 AFI->setHasSpills(true);
140
141 const MachineFrameInfo &MFI = MF.getFrameInfo();
142
143 MachineMemOperand *MMO = MF.getMachineMemOperand(
144 PtrInfo: MachinePointerInfo::getFixedStack(MF, FI: FrameIndex),
145 F: MachineMemOperand::MOStore, Size: MFI.getObjectSize(ObjectIdx: FrameIndex),
146 BaseAlignment: MFI.getObjectAlign(ObjectIdx: FrameIndex));
147
148 unsigned Opcode = 0;
149 if (TRI->isTypeLegalForClass(*RC, MVT::i8)) {
150 Opcode = AVR::STDPtrQRr;
151 } else if (TRI->isTypeLegalForClass(*RC, MVT::i16)) {
152 Opcode = AVR::STDWPtrQRr;
153 } else {
154 llvm_unreachable("Cannot store this register into a stack slot!");
155 }
156
157 BuildMI(MBB, MI, DebugLoc(), get(Opcode))
158 .addFrameIndex(FrameIndex)
159 .addImm(0)
160 .addReg(SrcReg, getKillRegState(B: isKill))
161 .addMemOperand(MMO);
162}
163
164void AVRInstrInfo::loadRegFromStackSlot(MachineBasicBlock &MBB,
165 MachineBasicBlock::iterator MI,
166 Register DestReg, int FrameIndex,
167 const TargetRegisterClass *RC,
168 const TargetRegisterInfo *TRI,
169 Register VReg) const {
170 MachineFunction &MF = *MBB.getParent();
171 const MachineFrameInfo &MFI = MF.getFrameInfo();
172
173 MachineMemOperand *MMO = MF.getMachineMemOperand(
174 PtrInfo: MachinePointerInfo::getFixedStack(MF, FI: FrameIndex),
175 F: MachineMemOperand::MOLoad, Size: MFI.getObjectSize(ObjectIdx: FrameIndex),
176 BaseAlignment: MFI.getObjectAlign(ObjectIdx: FrameIndex));
177
178 unsigned Opcode = 0;
179 if (TRI->isTypeLegalForClass(*RC, MVT::i8)) {
180 Opcode = AVR::LDDRdPtrQ;
181 } else if (TRI->isTypeLegalForClass(*RC, MVT::i16)) {
182 // Opcode = AVR::LDDWRdPtrQ;
183 //: FIXME: remove this once PR13375 gets fixed
184 Opcode = AVR::LDDWRdYQ;
185 } else {
186 llvm_unreachable("Cannot load this register from a stack slot!");
187 }
188
189 BuildMI(MBB, MI, DebugLoc(), get(Opcode), DestReg)
190 .addFrameIndex(FrameIndex)
191 .addImm(0)
192 .addMemOperand(MMO);
193}
194
195const MCInstrDesc &AVRInstrInfo::getBrCond(AVRCC::CondCodes CC) const {
196 switch (CC) {
197 default:
198 llvm_unreachable("Unknown condition code!");
199 case AVRCC::COND_EQ:
200 return get(AVR::BREQk);
201 case AVRCC::COND_NE:
202 return get(AVR::BRNEk);
203 case AVRCC::COND_GE:
204 return get(AVR::BRGEk);
205 case AVRCC::COND_LT:
206 return get(AVR::BRLTk);
207 case AVRCC::COND_SH:
208 return get(AVR::BRSHk);
209 case AVRCC::COND_LO:
210 return get(AVR::BRLOk);
211 case AVRCC::COND_MI:
212 return get(AVR::BRMIk);
213 case AVRCC::COND_PL:
214 return get(AVR::BRPLk);
215 }
216}
217
218AVRCC::CondCodes AVRInstrInfo::getCondFromBranchOpc(unsigned Opc) const {
219 switch (Opc) {
220 default:
221 return AVRCC::COND_INVALID;
222 case AVR::BREQk:
223 return AVRCC::COND_EQ;
224 case AVR::BRNEk:
225 return AVRCC::COND_NE;
226 case AVR::BRSHk:
227 return AVRCC::COND_SH;
228 case AVR::BRLOk:
229 return AVRCC::COND_LO;
230 case AVR::BRMIk:
231 return AVRCC::COND_MI;
232 case AVR::BRPLk:
233 return AVRCC::COND_PL;
234 case AVR::BRGEk:
235 return AVRCC::COND_GE;
236 case AVR::BRLTk:
237 return AVRCC::COND_LT;
238 }
239}
240
241AVRCC::CondCodes AVRInstrInfo::getOppositeCondition(AVRCC::CondCodes CC) const {
242 switch (CC) {
243 default:
244 llvm_unreachable("Invalid condition!");
245 case AVRCC::COND_EQ:
246 return AVRCC::COND_NE;
247 case AVRCC::COND_NE:
248 return AVRCC::COND_EQ;
249 case AVRCC::COND_SH:
250 return AVRCC::COND_LO;
251 case AVRCC::COND_LO:
252 return AVRCC::COND_SH;
253 case AVRCC::COND_GE:
254 return AVRCC::COND_LT;
255 case AVRCC::COND_LT:
256 return AVRCC::COND_GE;
257 case AVRCC::COND_MI:
258 return AVRCC::COND_PL;
259 case AVRCC::COND_PL:
260 return AVRCC::COND_MI;
261 }
262}
263
264bool AVRInstrInfo::analyzeBranch(MachineBasicBlock &MBB,
265 MachineBasicBlock *&TBB,
266 MachineBasicBlock *&FBB,
267 SmallVectorImpl<MachineOperand> &Cond,
268 bool AllowModify) const {
269 // Start from the bottom of the block and work up, examining the
270 // terminator instructions.
271 MachineBasicBlock::iterator I = MBB.end();
272 MachineBasicBlock::iterator UnCondBrIter = MBB.end();
273
274 while (I != MBB.begin()) {
275 --I;
276 if (I->isDebugInstr()) {
277 continue;
278 }
279
280 // Working from the bottom, when we see a non-terminator
281 // instruction, we're done.
282 if (!isUnpredicatedTerminator(*I)) {
283 break;
284 }
285
286 // A terminator that isn't a branch can't easily be handled
287 // by this analysis.
288 if (!I->getDesc().isBranch()) {
289 return true;
290 }
291
292 // Handle unconditional branches.
293 //: TODO: add here jmp
294 if (I->getOpcode() == AVR::RJMPk) {
295 UnCondBrIter = I;
296
297 if (!AllowModify) {
298 TBB = I->getOperand(i: 0).getMBB();
299 continue;
300 }
301
302 // If the block has any instructions after a JMP, delete them.
303 MBB.erase(std::next(I), MBB.end());
304
305 Cond.clear();
306 FBB = nullptr;
307
308 // Delete the JMP if it's equivalent to a fall-through.
309 if (MBB.isLayoutSuccessor(MBB: I->getOperand(i: 0).getMBB())) {
310 TBB = nullptr;
311 I->eraseFromParent();
312 I = MBB.end();
313 UnCondBrIter = MBB.end();
314 continue;
315 }
316
317 // TBB is used to indicate the unconditinal destination.
318 TBB = I->getOperand(i: 0).getMBB();
319 continue;
320 }
321
322 // Handle conditional branches.
323 AVRCC::CondCodes BranchCode = getCondFromBranchOpc(Opc: I->getOpcode());
324 if (BranchCode == AVRCC::COND_INVALID) {
325 return true; // Can't handle indirect branch.
326 }
327
328 // Working from the bottom, handle the first conditional branch.
329 if (Cond.empty()) {
330 MachineBasicBlock *TargetBB = I->getOperand(i: 0).getMBB();
331 if (AllowModify && UnCondBrIter != MBB.end() &&
332 MBB.isLayoutSuccessor(MBB: TargetBB)) {
333 // If we can modify the code and it ends in something like:
334 //
335 // jCC L1
336 // jmp L2
337 // L1:
338 // ...
339 // L2:
340 //
341 // Then we can change this to:
342 //
343 // jnCC L2
344 // L1:
345 // ...
346 // L2:
347 //
348 // Which is a bit more efficient.
349 // We conditionally jump to the fall-through block.
350 BranchCode = getOppositeCondition(CC: BranchCode);
351 unsigned JNCC = getBrCond(CC: BranchCode).getOpcode();
352 MachineBasicBlock::iterator OldInst = I;
353
354 BuildMI(MBB, UnCondBrIter, MBB.findDebugLoc(MBBI: I), get(JNCC))
355 .addMBB(UnCondBrIter->getOperand(i: 0).getMBB());
356 BuildMI(MBB, UnCondBrIter, MBB.findDebugLoc(I), get(AVR::RJMPk))
357 .addMBB(TargetBB);
358
359 OldInst->eraseFromParent();
360 UnCondBrIter->eraseFromParent();
361
362 // Restart the analysis.
363 UnCondBrIter = MBB.end();
364 I = MBB.end();
365 continue;
366 }
367
368 FBB = TBB;
369 TBB = I->getOperand(i: 0).getMBB();
370 Cond.push_back(MachineOperand::CreateImm(Val: BranchCode));
371 continue;
372 }
373
374 // Handle subsequent conditional branches. Only handle the case where all
375 // conditional branches branch to the same destination.
376 assert(Cond.size() == 1);
377 assert(TBB);
378
379 // Only handle the case where all conditional branches branch to
380 // the same destination.
381 if (TBB != I->getOperand(i: 0).getMBB()) {
382 return true;
383 }
384
385 AVRCC::CondCodes OldBranchCode = (AVRCC::CondCodes)Cond[0].getImm();
386 // If the conditions are the same, we can leave them alone.
387 if (OldBranchCode == BranchCode) {
388 continue;
389 }
390
391 return true;
392 }
393
394 return false;
395}
396
397unsigned AVRInstrInfo::insertBranch(MachineBasicBlock &MBB,
398 MachineBasicBlock *TBB,
399 MachineBasicBlock *FBB,
400 ArrayRef<MachineOperand> Cond,
401 const DebugLoc &DL, int *BytesAdded) const {
402 if (BytesAdded)
403 *BytesAdded = 0;
404
405 // Shouldn't be a fall through.
406 assert(TBB && "insertBranch must not be told to insert a fallthrough");
407 assert((Cond.size() == 1 || Cond.size() == 0) &&
408 "AVR branch conditions have one component!");
409
410 if (Cond.empty()) {
411 assert(!FBB && "Unconditional branch with multiple successors!");
412 auto &MI = *BuildMI(&MBB, DL, get(AVR::RJMPk)).addMBB(TBB);
413 if (BytesAdded)
414 *BytesAdded += getInstSizeInBytes(MI: MI);
415 return 1;
416 }
417
418 // Conditional branch.
419 unsigned Count = 0;
420 AVRCC::CondCodes CC = (AVRCC::CondCodes)Cond[0].getImm();
421 auto &CondMI = *BuildMI(BB: &MBB, MIMD: DL, MCID: getBrCond(CC)).addMBB(MBB: TBB);
422
423 if (BytesAdded)
424 *BytesAdded += getInstSizeInBytes(MI: CondMI);
425 ++Count;
426
427 if (FBB) {
428 // Two-way Conditional branch. Insert the second branch.
429 auto &MI = *BuildMI(&MBB, DL, get(AVR::RJMPk)).addMBB(FBB);
430 if (BytesAdded)
431 *BytesAdded += getInstSizeInBytes(MI: MI);
432 ++Count;
433 }
434
435 return Count;
436}
437
438unsigned AVRInstrInfo::removeBranch(MachineBasicBlock &MBB,
439 int *BytesRemoved) const {
440 if (BytesRemoved)
441 *BytesRemoved = 0;
442
443 MachineBasicBlock::iterator I = MBB.end();
444 unsigned Count = 0;
445
446 while (I != MBB.begin()) {
447 --I;
448 if (I->isDebugInstr()) {
449 continue;
450 }
451 //: TODO: add here the missing jmp instructions once they are implemented
452 // like jmp, {e}ijmp, and other cond branches, ...
453 if (I->getOpcode() != AVR::RJMPk &&
454 getCondFromBranchOpc(I->getOpcode()) == AVRCC::COND_INVALID) {
455 break;
456 }
457
458 // Remove the branch.
459 if (BytesRemoved)
460 *BytesRemoved += getInstSizeInBytes(MI: *I);
461 I->eraseFromParent();
462 I = MBB.end();
463 ++Count;
464 }
465
466 return Count;
467}
468
469bool AVRInstrInfo::reverseBranchCondition(
470 SmallVectorImpl<MachineOperand> &Cond) const {
471 assert(Cond.size() == 1 && "Invalid AVR branch condition!");
472
473 AVRCC::CondCodes CC = static_cast<AVRCC::CondCodes>(Cond[0].getImm());
474 Cond[0].setImm(getOppositeCondition(CC));
475
476 return false;
477}
478
479unsigned AVRInstrInfo::getInstSizeInBytes(const MachineInstr &MI) const {
480 unsigned Opcode = MI.getOpcode();
481
482 switch (Opcode) {
483 // A regular instruction
484 default: {
485 const MCInstrDesc &Desc = get(Opcode);
486 return Desc.getSize();
487 }
488 case TargetOpcode::EH_LABEL:
489 case TargetOpcode::IMPLICIT_DEF:
490 case TargetOpcode::KILL:
491 case TargetOpcode::DBG_VALUE:
492 return 0;
493 case TargetOpcode::INLINEASM:
494 case TargetOpcode::INLINEASM_BR: {
495 const MachineFunction &MF = *MI.getParent()->getParent();
496 const AVRTargetMachine &TM =
497 static_cast<const AVRTargetMachine &>(MF.getTarget());
498 const TargetInstrInfo &TII = *STI.getInstrInfo();
499 return TII.getInlineAsmLength(Str: MI.getOperand(i: 0).getSymbolName(),
500 MAI: *TM.getMCAsmInfo());
501 }
502 }
503}
504
505MachineBasicBlock *
506AVRInstrInfo::getBranchDestBlock(const MachineInstr &MI) const {
507 switch (MI.getOpcode()) {
508 default:
509 llvm_unreachable("unexpected opcode!");
510 case AVR::JMPk:
511 case AVR::CALLk:
512 case AVR::RCALLk:
513 case AVR::RJMPk:
514 case AVR::BREQk:
515 case AVR::BRNEk:
516 case AVR::BRSHk:
517 case AVR::BRLOk:
518 case AVR::BRMIk:
519 case AVR::BRPLk:
520 case AVR::BRGEk:
521 case AVR::BRLTk:
522 return MI.getOperand(i: 0).getMBB();
523 case AVR::BRBSsk:
524 case AVR::BRBCsk:
525 return MI.getOperand(i: 1).getMBB();
526 case AVR::SBRCRrB:
527 case AVR::SBRSRrB:
528 case AVR::SBICAb:
529 case AVR::SBISAb:
530 llvm_unreachable("unimplemented branch instructions");
531 }
532}
533
534bool AVRInstrInfo::isBranchOffsetInRange(unsigned BranchOp,
535 int64_t BrOffset) const {
536
537 switch (BranchOp) {
538 default:
539 llvm_unreachable("unexpected opcode!");
540 case AVR::JMPk:
541 case AVR::CALLk:
542 return STI.hasJMPCALL();
543 case AVR::RCALLk:
544 case AVR::RJMPk:
545 return isIntN(N: 13, x: BrOffset);
546 case AVR::BRBSsk:
547 case AVR::BRBCsk:
548 case AVR::BREQk:
549 case AVR::BRNEk:
550 case AVR::BRSHk:
551 case AVR::BRLOk:
552 case AVR::BRMIk:
553 case AVR::BRPLk:
554 case AVR::BRGEk:
555 case AVR::BRLTk:
556 return isIntN(N: 7, x: BrOffset);
557 }
558}
559
560void AVRInstrInfo::insertIndirectBranch(MachineBasicBlock &MBB,
561 MachineBasicBlock &NewDestBB,
562 MachineBasicBlock &RestoreBB,
563 const DebugLoc &DL, int64_t BrOffset,
564 RegScavenger *RS) const {
565 // This method inserts a *direct* branch (JMP), despite its name.
566 // LLVM calls this method to fixup unconditional branches; it never calls
567 // insertBranch or some hypothetical "insertDirectBranch".
568 // See lib/CodeGen/RegisterRelaxation.cpp for details.
569 // We end up here when a jump is too long for a RJMP instruction.
570 if (STI.hasJMPCALL())
571 BuildMI(&MBB, DL, get(AVR::JMPk)).addMBB(&NewDestBB);
572 else
573 // The RJMP may jump to a far place beyond its legal range. We let the
574 // linker to report 'out of range' rather than crash, or silently emit
575 // incorrect assembly code.
576 BuildMI(&MBB, DL, get(AVR::RJMPk)).addMBB(&NewDestBB);
577}
578
579} // end of namespace llvm
580

source code of llvm/lib/Target/AVR/AVRInstrInfo.cpp