xref: /freebsd/contrib/llvm-project/llvm/lib/CodeGen/GlobalISel/CSEInfo.cpp (revision 9f23cbd6cae82fd77edfad7173432fa8dccd0a95) 
1 //===- CSEInfo.cpp ------------------------------===//
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 //
10 //===----------------------------------------------------------------------===//
11 #include "llvm/CodeGen/GlobalISel/CSEInfo.h"
12 #include "llvm/CodeGen/MachineRegisterInfo.h"
13 #include "llvm/InitializePasses.h"
14 #include "llvm/Support/Error.h"
15 
16 #define DEBUG_TYPE "cseinfo"
17 
18 using namespace llvm;
19 char llvm::GISelCSEAnalysisWrapperPass::ID = 0;
20 GISelCSEAnalysisWrapperPass::GISelCSEAnalysisWrapperPass()
21     : MachineFunctionPass(ID) {
22   initializeGISelCSEAnalysisWrapperPassPass(*PassRegistry::getPassRegistry());
23 }
24 INITIALIZE_PASS_BEGIN(GISelCSEAnalysisWrapperPass, DEBUG_TYPE,
25                       "Analysis containing CSE Info", false, true)
26 INITIALIZE_PASS_END(GISelCSEAnalysisWrapperPass, DEBUG_TYPE,
27                     "Analysis containing CSE Info", false, true)
28 
29 /// -------- UniqueMachineInstr -------------//
30 
31 void UniqueMachineInstr::Profile(FoldingSetNodeID &ID) {
32   GISelInstProfileBuilder(ID, MI->getMF()->getRegInfo()).addNodeID(MI);
33 }
34 /// -----------------------------------------
35 
36 /// --------- CSEConfigFull ---------- ///
37 bool CSEConfigFull::shouldCSEOpc(unsigned Opc) {
38   switch (Opc) {
39   default:
40     break;
41   case TargetOpcode::G_ADD:
42   case TargetOpcode::G_AND:
43   case TargetOpcode::G_ASHR:
44   case TargetOpcode::G_LSHR:
45   case TargetOpcode::G_MUL:
46   case TargetOpcode::G_OR:
47   case TargetOpcode::G_SHL:
48   case TargetOpcode::G_SUB:
49   case TargetOpcode::G_XOR:
50   case TargetOpcode::G_UDIV:
51   case TargetOpcode::G_SDIV:
52   case TargetOpcode::G_UREM:
53   case TargetOpcode::G_SREM:
54   case TargetOpcode::G_CONSTANT:
55   case TargetOpcode::G_FCONSTANT:
56   case TargetOpcode::G_IMPLICIT_DEF:
57   case TargetOpcode::G_ZEXT:
58   case TargetOpcode::G_SEXT:
59   case TargetOpcode::G_ANYEXT:
60   case TargetOpcode::G_UNMERGE_VALUES:
61   case TargetOpcode::G_TRUNC:
62   case TargetOpcode::G_PTR_ADD:
63   case TargetOpcode::G_EXTRACT:
64   case TargetOpcode::G_SELECT:
65   case TargetOpcode::G_BUILD_VECTOR:
66   case TargetOpcode::G_BUILD_VECTOR_TRUNC:
67   case TargetOpcode::G_SEXT_INREG:
68     return true;
69   }
70   return false;
71 }
72 
73 bool CSEConfigConstantOnly::shouldCSEOpc(unsigned Opc) {
74   return Opc == TargetOpcode::G_CONSTANT || Opc == TargetOpcode::G_FCONSTANT ||
75          Opc == TargetOpcode::G_IMPLICIT_DEF;
76 }
77 
78 std::unique_ptr<CSEConfigBase>
79 llvm::getStandardCSEConfigForOpt(CodeGenOpt::Level Level) {
80   std::unique_ptr<CSEConfigBase> Config;
81   if (Level == CodeGenOpt::None)
82     Config = std::make_unique<CSEConfigConstantOnly>();
83   else
84     Config = std::make_unique<CSEConfigFull>();
85   return Config;
86 }
87 
88 /// -----------------------------------------
89 
90 /// -------- GISelCSEInfo -------------//
91 void GISelCSEInfo::setMF(MachineFunction &MF) {
92   this->MF = &MF;
93   this->MRI = &MF.getRegInfo();
94 }
95 
96 GISelCSEInfo::~GISelCSEInfo() = default;
97 
98 bool GISelCSEInfo::isUniqueMachineInstValid(
99     const UniqueMachineInstr &UMI) const {
100   // Should we check here and assert that the instruction has been fully
101   // constructed?
102   // FIXME: Any other checks required to be done here? Remove this method if
103   // none.
104   return true;
105 }
106 
107 void GISelCSEInfo::invalidateUniqueMachineInstr(UniqueMachineInstr *UMI) {
108   bool Removed = CSEMap.RemoveNode(UMI);
109   (void)Removed;
110   assert(Removed && "Invalidation called on invalid UMI");
111   // FIXME: Should UMI be deallocated/destroyed?
112 }
113 
114 UniqueMachineInstr *GISelCSEInfo::getNodeIfExists(FoldingSetNodeID &ID,
115                                                   MachineBasicBlock *MBB,
116                                                   void *&InsertPos) {
117   auto *Node = CSEMap.FindNodeOrInsertPos(ID, InsertPos);
118   if (Node) {
119     if (!isUniqueMachineInstValid(*Node)) {
120       invalidateUniqueMachineInstr(Node);
121       return nullptr;
122     }
123 
124     if (Node->MI->getParent() != MBB)
125       return nullptr;
126   }
127   return Node;
128 }
129 
130 void GISelCSEInfo::insertNode(UniqueMachineInstr *UMI, void *InsertPos) {
131   handleRecordedInsts();
132   assert(UMI);
133   UniqueMachineInstr *MaybeNewNode = UMI;
134   if (InsertPos)
135     CSEMap.InsertNode(UMI, InsertPos);
136   else
137     MaybeNewNode = CSEMap.GetOrInsertNode(UMI);
138   if (MaybeNewNode != UMI) {
139     // A similar node exists in the folding set. Let's ignore this one.
140     return;
141   }
142   assert(InstrMapping.count(UMI->MI) == 0 &&
143          "This instruction should not be in the map");
144   InstrMapping[UMI->MI] = MaybeNewNode;
145 }
146 
147 UniqueMachineInstr *GISelCSEInfo::getUniqueInstrForMI(const MachineInstr *MI) {
148   assert(shouldCSE(MI->getOpcode()) && "Trying to CSE an unsupported Node");
149   auto *Node = new (UniqueInstrAllocator) UniqueMachineInstr(MI);
150   return Node;
151 }
152 
153 void GISelCSEInfo::insertInstr(MachineInstr *MI, void *InsertPos) {
154   assert(MI);
155   // If it exists in temporary insts, remove it.
156   TemporaryInsts.remove(MI);
157   auto *Node = getUniqueInstrForMI(MI);
158   insertNode(Node, InsertPos);
159 }
160 
161 MachineInstr *GISelCSEInfo::getMachineInstrIfExists(FoldingSetNodeID &ID,
162                                                     MachineBasicBlock *MBB,
163                                                     void *&InsertPos) {
164   handleRecordedInsts();
165   if (auto *Inst = getNodeIfExists(ID, MBB, InsertPos)) {
166     LLVM_DEBUG(dbgs() << "CSEInfo::Found Instr " << *Inst->MI;);
167     return const_cast<MachineInstr *>(Inst->MI);
168   }
169   return nullptr;
170 }
171 
172 void GISelCSEInfo::countOpcodeHit(unsigned Opc) {
173 #ifndef NDEBUG
174   if (OpcodeHitTable.count(Opc))
175     OpcodeHitTable[Opc] += 1;
176   else
177     OpcodeHitTable[Opc] = 1;
178 #endif
179   // Else do nothing.
180 }
181 
182 void GISelCSEInfo::recordNewInstruction(MachineInstr *MI) {
183   if (shouldCSE(MI->getOpcode())) {
184     TemporaryInsts.insert(MI);
185     LLVM_DEBUG(dbgs() << "CSEInfo::Recording new MI " << *MI);
186   }
187 }
188 
189 void GISelCSEInfo::handleRecordedInst(MachineInstr *MI) {
190   assert(shouldCSE(MI->getOpcode()) && "Invalid instruction for CSE");
191   auto *UMI = InstrMapping.lookup(MI);
192   LLVM_DEBUG(dbgs() << "CSEInfo::Handling recorded MI " << *MI);
193   if (UMI) {
194     // Invalidate this MI.
195     invalidateUniqueMachineInstr(UMI);
196     InstrMapping.erase(MI);
197   }
198   /// Now insert the new instruction.
199   if (UMI) {
200     /// We'll reuse the same UniqueMachineInstr to avoid the new
201     /// allocation.
202     *UMI = UniqueMachineInstr(MI);
203     insertNode(UMI, nullptr);
204   } else {
205     /// This is a new instruction. Allocate a new UniqueMachineInstr and
206     /// Insert.
207     insertInstr(MI);
208   }
209 }
210 
211 void GISelCSEInfo::handleRemoveInst(MachineInstr *MI) {
212   if (auto *UMI = InstrMapping.lookup(MI)) {
213     invalidateUniqueMachineInstr(UMI);
214     InstrMapping.erase(MI);
215   }
216   TemporaryInsts.remove(MI);
217 }
218 
219 void GISelCSEInfo::handleRecordedInsts() {
220   while (!TemporaryInsts.empty()) {
221     auto *MI = TemporaryInsts.pop_back_val();
222     handleRecordedInst(MI);
223   }
224 }
225 
226 bool GISelCSEInfo::shouldCSE(unsigned Opc) const {
227   assert(CSEOpt.get() && "CSEConfig not set");
228   return CSEOpt->shouldCSEOpc(Opc);
229 }
230 
231 void GISelCSEInfo::erasingInstr(MachineInstr &MI) { handleRemoveInst(&MI); }
232 void GISelCSEInfo::createdInstr(MachineInstr &MI) { recordNewInstruction(&MI); }
233 void GISelCSEInfo::changingInstr(MachineInstr &MI) {
234   // For now, perform erase, followed by insert.
235   erasingInstr(MI);
236   createdInstr(MI);
237 }
238 void GISelCSEInfo::changedInstr(MachineInstr &MI) { changingInstr(MI); }
239 
240 void GISelCSEInfo::analyze(MachineFunction &MF) {
241   setMF(MF);
242   for (auto &MBB : MF) {
243     if (MBB.empty())
244       continue;
245     for (MachineInstr &MI : MBB) {
246       if (!shouldCSE(MI.getOpcode()))
247         continue;
248       LLVM_DEBUG(dbgs() << "CSEInfo::Add MI: " << MI);
249       insertInstr(&MI);
250     }
251   }
252 }
253 
254 void GISelCSEInfo::releaseMemory() {
255   print();
256   CSEMap.clear();
257   InstrMapping.clear();
258   UniqueInstrAllocator.Reset();
259   TemporaryInsts.clear();
260   CSEOpt.reset();
261   MRI = nullptr;
262   MF = nullptr;
263 #ifndef NDEBUG
264   OpcodeHitTable.clear();
265 #endif
266 }
267 
268 #ifndef NDEBUG
269 static const char *stringify(const MachineInstr *MI, std::string &S) {
270   raw_string_ostream OS(S);
271   OS << *MI;
272   return OS.str().c_str();
273 }
274 #endif
275 
276 Error GISelCSEInfo::verify() {
277 #ifndef NDEBUG
278   std::string S1, S2;
279   handleRecordedInsts();
280   // For each instruction in map from MI -> UMI,
281   // Profile(MI) and make sure UMI is found for that profile.
282   for (auto &It : InstrMapping) {
283     FoldingSetNodeID TmpID;
284     GISelInstProfileBuilder(TmpID, *MRI).addNodeID(It.first);
285     void *InsertPos;
286     UniqueMachineInstr *FoundNode =
287         CSEMap.FindNodeOrInsertPos(TmpID, InsertPos);
288     if (FoundNode != It.second)
289       return createStringError(std::errc::not_supported,
290                                "CSEMap mismatch, InstrMapping has MIs without "
291                                "corresponding Nodes in CSEMap:\n%s",
292                                stringify(It.second->MI, S1));
293   }
294 
295   // For every node in the CSEMap, make sure that the InstrMapping
296   // points to it.
297   for (const UniqueMachineInstr &UMI : CSEMap) {
298     if (!InstrMapping.count(UMI.MI))
299       return createStringError(std::errc::not_supported,
300                                "Node in CSE without InstrMapping:\n%s",
301                                stringify(UMI.MI, S1));
302 
303     if (InstrMapping[UMI.MI] != &UMI)
304       return createStringError(std::make_error_code(std::errc::not_supported),
305                                "Mismatch in CSE mapping:\n%s\n%s",
306                                stringify(InstrMapping[UMI.MI]->MI, S1),
307                                stringify(UMI.MI, S2));
308   }
309 #endif
310   return Error::success();
311 }
312 
313 void GISelCSEInfo::print() {
314   LLVM_DEBUG(for (auto &It
315                   : OpcodeHitTable) {
316     dbgs() << "CSEInfo::CSE Hit for Opc " << It.first << " : " << It.second
317            << "\n";
318   };);
319 }
320 /// -----------------------------------------
321 // ---- Profiling methods for FoldingSetNode --- //
322 const GISelInstProfileBuilder &
323 GISelInstProfileBuilder::addNodeID(const MachineInstr *MI) const {
324   addNodeIDMBB(MI->getParent());
325   addNodeIDOpcode(MI->getOpcode());
326   for (const auto &Op : MI->operands())
327     addNodeIDMachineOperand(Op);
328   addNodeIDFlag(MI->getFlags());
329   return *this;
330 }
331 
332 const GISelInstProfileBuilder &
333 GISelInstProfileBuilder::addNodeIDOpcode(unsigned Opc) const {
334   ID.AddInteger(Opc);
335   return *this;
336 }
337 
338 const GISelInstProfileBuilder &
339 GISelInstProfileBuilder::addNodeIDRegType(const LLT Ty) const {
340   uint64_t Val = Ty.getUniqueRAWLLTData();
341   ID.AddInteger(Val);
342   return *this;
343 }
344 
345 const GISelInstProfileBuilder &
346 GISelInstProfileBuilder::addNodeIDRegType(const TargetRegisterClass *RC) const {
347   ID.AddPointer(RC);
348   return *this;
349 }
350 
351 const GISelInstProfileBuilder &
352 GISelInstProfileBuilder::addNodeIDRegType(const RegisterBank *RB) const {
353   ID.AddPointer(RB);
354   return *this;
355 }
356 
357 const GISelInstProfileBuilder &
358 GISelInstProfileBuilder::addNodeIDImmediate(int64_t Imm) const {
359   ID.AddInteger(Imm);
360   return *this;
361 }
362 
363 const GISelInstProfileBuilder &
364 GISelInstProfileBuilder::addNodeIDRegNum(Register Reg) const {
365   ID.AddInteger(Reg);
366   return *this;
367 }
368 
369 const GISelInstProfileBuilder &
370 GISelInstProfileBuilder::addNodeIDRegType(const Register Reg) const {
371   addNodeIDMachineOperand(MachineOperand::CreateReg(Reg, false));
372   return *this;
373 }
374 
375 const GISelInstProfileBuilder &
376 GISelInstProfileBuilder::addNodeIDMBB(const MachineBasicBlock *MBB) const {
377   ID.AddPointer(MBB);
378   return *this;
379 }
380 
381 const GISelInstProfileBuilder &
382 GISelInstProfileBuilder::addNodeIDFlag(unsigned Flag) const {
383   if (Flag)
384     ID.AddInteger(Flag);
385   return *this;
386 }
387 
388 const GISelInstProfileBuilder &
389 GISelInstProfileBuilder::addNodeIDReg(Register Reg) const {
390   LLT Ty = MRI.getType(Reg);
391   if (Ty.isValid())
392     addNodeIDRegType(Ty);
393 
394   if (const RegClassOrRegBank &RCOrRB = MRI.getRegClassOrRegBank(Reg)) {
395     if (const auto *RB = RCOrRB.dyn_cast<const RegisterBank *>())
396       addNodeIDRegType(RB);
397     else if (const auto *RC = RCOrRB.dyn_cast<const TargetRegisterClass *>())
398       addNodeIDRegType(RC);
399   }
400   return *this;
401 }
402 
403 const GISelInstProfileBuilder &GISelInstProfileBuilder::addNodeIDMachineOperand(
404     const MachineOperand &MO) const {
405   if (MO.isReg()) {
406     Register Reg = MO.getReg();
407     if (!MO.isDef())
408       addNodeIDRegNum(Reg);
409 
410     // Profile the register properties.
411     addNodeIDReg(Reg);
412     assert(!MO.isImplicit() && "Unhandled case");
413   } else if (MO.isImm())
414     ID.AddInteger(MO.getImm());
415   else if (MO.isCImm())
416     ID.AddPointer(MO.getCImm());
417   else if (MO.isFPImm())
418     ID.AddPointer(MO.getFPImm());
419   else if (MO.isPredicate())
420     ID.AddInteger(MO.getPredicate());
421   else
422     llvm_unreachable("Unhandled operand type");
423   // Handle other types
424   return *this;
425 }
426 
427 GISelCSEInfo &
428 GISelCSEAnalysisWrapper::get(std::unique_ptr<CSEConfigBase> CSEOpt,
429                              bool Recompute) {
430   if (!AlreadyComputed || Recompute) {
431     Info.releaseMemory();
432     Info.setCSEConfig(std::move(CSEOpt));
433     Info.analyze(*MF);
434     AlreadyComputed = true;
435   }
436   return Info;
437 }
438 void GISelCSEAnalysisWrapperPass::getAnalysisUsage(AnalysisUsage &AU) const {
439   AU.setPreservesAll();
440   MachineFunctionPass::getAnalysisUsage(AU);
441 }
442 
443 bool GISelCSEAnalysisWrapperPass::runOnMachineFunction(MachineFunction &MF) {
444   releaseMemory();
445   Wrapper.setMF(MF);
446   return false;
447 }
448