xref: /freebsd/contrib/llvm-project/llvm/lib/CodeGen/MachineFunction.cpp (revision ec0ea6efa1ad229d75c394c1a9b9cac33af2b1d3)
1 //===- MachineFunction.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 // Collect native machine code information for a function.  This allows
10 // target-specific information about the generated code to be stored with each
11 // function.
12 //
13 //===----------------------------------------------------------------------===//
14 
15 #include "llvm/CodeGen/MachineFunction.h"
16 #include "llvm/ADT/BitVector.h"
17 #include "llvm/ADT/DenseMap.h"
18 #include "llvm/ADT/DenseSet.h"
19 #include "llvm/ADT/STLExtras.h"
20 #include "llvm/ADT/SmallString.h"
21 #include "llvm/ADT/SmallVector.h"
22 #include "llvm/ADT/StringRef.h"
23 #include "llvm/ADT/Twine.h"
24 #include "llvm/Analysis/ConstantFolding.h"
25 #include "llvm/Analysis/EHPersonalities.h"
26 #include "llvm/CodeGen/MachineBasicBlock.h"
27 #include "llvm/CodeGen/MachineConstantPool.h"
28 #include "llvm/CodeGen/MachineFrameInfo.h"
29 #include "llvm/CodeGen/MachineInstr.h"
30 #include "llvm/CodeGen/MachineJumpTableInfo.h"
31 #include "llvm/CodeGen/MachineMemOperand.h"
32 #include "llvm/CodeGen/MachineModuleInfo.h"
33 #include "llvm/CodeGen/MachineRegisterInfo.h"
34 #include "llvm/CodeGen/PseudoSourceValue.h"
35 #include "llvm/CodeGen/TargetFrameLowering.h"
36 #include "llvm/CodeGen/TargetInstrInfo.h"
37 #include "llvm/CodeGen/TargetLowering.h"
38 #include "llvm/CodeGen/TargetRegisterInfo.h"
39 #include "llvm/CodeGen/TargetSubtargetInfo.h"
40 #include "llvm/CodeGen/WasmEHFuncInfo.h"
41 #include "llvm/CodeGen/WinEHFuncInfo.h"
42 #include "llvm/Config/llvm-config.h"
43 #include "llvm/IR/Attributes.h"
44 #include "llvm/IR/BasicBlock.h"
45 #include "llvm/IR/Constant.h"
46 #include "llvm/IR/DataLayout.h"
47 #include "llvm/IR/DebugInfoMetadata.h"
48 #include "llvm/IR/DerivedTypes.h"
49 #include "llvm/IR/Function.h"
50 #include "llvm/IR/GlobalValue.h"
51 #include "llvm/IR/Instruction.h"
52 #include "llvm/IR/Instructions.h"
53 #include "llvm/IR/Metadata.h"
54 #include "llvm/IR/Module.h"
55 #include "llvm/IR/ModuleSlotTracker.h"
56 #include "llvm/IR/Value.h"
57 #include "llvm/MC/MCContext.h"
58 #include "llvm/MC/MCSymbol.h"
59 #include "llvm/MC/SectionKind.h"
60 #include "llvm/Support/Casting.h"
61 #include "llvm/Support/CommandLine.h"
62 #include "llvm/Support/Compiler.h"
63 #include "llvm/Support/DOTGraphTraits.h"
64 #include "llvm/Support/Debug.h"
65 #include "llvm/Support/ErrorHandling.h"
66 #include "llvm/Support/GraphWriter.h"
67 #include "llvm/Support/raw_ostream.h"
68 #include "llvm/Target/TargetMachine.h"
69 #include <algorithm>
70 #include <cassert>
71 #include <cstddef>
72 #include <cstdint>
73 #include <iterator>
74 #include <string>
75 #include <type_traits>
76 #include <utility>
77 #include <vector>
78 
79 using namespace llvm;
80 
81 #define DEBUG_TYPE "codegen"
82 
83 static cl::opt<unsigned> AlignAllFunctions(
84     "align-all-functions",
85     cl::desc("Force the alignment of all functions in log2 format (e.g. 4 "
86              "means align on 16B boundaries)."),
87     cl::init(0), cl::Hidden);
88 
89 static const char *getPropertyName(MachineFunctionProperties::Property Prop) {
90   using P = MachineFunctionProperties::Property;
91 
92   switch(Prop) {
93   case P::FailedISel: return "FailedISel";
94   case P::IsSSA: return "IsSSA";
95   case P::Legalized: return "Legalized";
96   case P::NoPHIs: return "NoPHIs";
97   case P::NoVRegs: return "NoVRegs";
98   case P::RegBankSelected: return "RegBankSelected";
99   case P::Selected: return "Selected";
100   case P::TracksLiveness: return "TracksLiveness";
101   case P::TiedOpsRewritten: return "TiedOpsRewritten";
102   }
103   llvm_unreachable("Invalid machine function property");
104 }
105 
106 // Pin the vtable to this file.
107 void MachineFunction::Delegate::anchor() {}
108 
109 void MachineFunctionProperties::print(raw_ostream &OS) const {
110   const char *Separator = "";
111   for (BitVector::size_type I = 0; I < Properties.size(); ++I) {
112     if (!Properties[I])
113       continue;
114     OS << Separator << getPropertyName(static_cast<Property>(I));
115     Separator = ", ";
116   }
117 }
118 
119 //===----------------------------------------------------------------------===//
120 // MachineFunction implementation
121 //===----------------------------------------------------------------------===//
122 
123 // Out-of-line virtual method.
124 MachineFunctionInfo::~MachineFunctionInfo() = default;
125 
126 void ilist_alloc_traits<MachineBasicBlock>::deleteNode(MachineBasicBlock *MBB) {
127   MBB->getParent()->DeleteMachineBasicBlock(MBB);
128 }
129 
130 static inline unsigned getFnStackAlignment(const TargetSubtargetInfo *STI,
131                                            const Function &F) {
132   if (F.hasFnAttribute(Attribute::StackAlignment))
133     return F.getFnStackAlignment();
134   return STI->getFrameLowering()->getStackAlign().value();
135 }
136 
137 MachineFunction::MachineFunction(Function &F, const LLVMTargetMachine &Target,
138                                  const TargetSubtargetInfo &STI,
139                                  unsigned FunctionNum, MachineModuleInfo &mmi)
140     : F(F), Target(Target), STI(&STI), Ctx(mmi.getContext()), MMI(mmi) {
141   FunctionNumber = FunctionNum;
142   init();
143 }
144 
145 void MachineFunction::handleInsertion(MachineInstr &MI) {
146   if (TheDelegate)
147     TheDelegate->MF_HandleInsertion(MI);
148 }
149 
150 void MachineFunction::handleRemoval(MachineInstr &MI) {
151   if (TheDelegate)
152     TheDelegate->MF_HandleRemoval(MI);
153 }
154 
155 void MachineFunction::init() {
156   // Assume the function starts in SSA form with correct liveness.
157   Properties.set(MachineFunctionProperties::Property::IsSSA);
158   Properties.set(MachineFunctionProperties::Property::TracksLiveness);
159   if (STI->getRegisterInfo())
160     RegInfo = new (Allocator) MachineRegisterInfo(this);
161   else
162     RegInfo = nullptr;
163 
164   MFInfo = nullptr;
165   // We can realign the stack if the target supports it and the user hasn't
166   // explicitly asked us not to.
167   bool CanRealignSP = STI->getFrameLowering()->isStackRealignable() &&
168                       !F.hasFnAttribute("no-realign-stack");
169   FrameInfo = new (Allocator) MachineFrameInfo(
170       getFnStackAlignment(STI, F), /*StackRealignable=*/CanRealignSP,
171       /*ForcedRealign=*/CanRealignSP &&
172           F.hasFnAttribute(Attribute::StackAlignment));
173 
174   if (F.hasFnAttribute(Attribute::StackAlignment))
175     FrameInfo->ensureMaxAlignment(*F.getFnStackAlign());
176 
177   ConstantPool = new (Allocator) MachineConstantPool(getDataLayout());
178   Alignment = STI->getTargetLowering()->getMinFunctionAlignment();
179 
180   // FIXME: Shouldn't use pref alignment if explicit alignment is set on F.
181   // FIXME: Use Function::hasOptSize().
182   if (!F.hasFnAttribute(Attribute::OptimizeForSize))
183     Alignment = std::max(Alignment,
184                          STI->getTargetLowering()->getPrefFunctionAlignment());
185 
186   if (AlignAllFunctions)
187     Alignment = Align(1ULL << AlignAllFunctions);
188 
189   JumpTableInfo = nullptr;
190 
191   if (isFuncletEHPersonality(classifyEHPersonality(
192           F.hasPersonalityFn() ? F.getPersonalityFn() : nullptr))) {
193     WinEHInfo = new (Allocator) WinEHFuncInfo();
194   }
195 
196   if (isScopedEHPersonality(classifyEHPersonality(
197           F.hasPersonalityFn() ? F.getPersonalityFn() : nullptr))) {
198     WasmEHInfo = new (Allocator) WasmEHFuncInfo();
199   }
200 
201   assert(Target.isCompatibleDataLayout(getDataLayout()) &&
202          "Can't create a MachineFunction using a Module with a "
203          "Target-incompatible DataLayout attached\n");
204 
205   PSVManager =
206     std::make_unique<PseudoSourceValueManager>(*(getSubtarget().
207                                                   getInstrInfo()));
208 }
209 
210 MachineFunction::~MachineFunction() {
211   clear();
212 }
213 
214 void MachineFunction::clear() {
215   Properties.reset();
216   // Don't call destructors on MachineInstr and MachineOperand. All of their
217   // memory comes from the BumpPtrAllocator which is about to be purged.
218   //
219   // Do call MachineBasicBlock destructors, it contains std::vectors.
220   for (iterator I = begin(), E = end(); I != E; I = BasicBlocks.erase(I))
221     I->Insts.clearAndLeakNodesUnsafely();
222   MBBNumbering.clear();
223 
224   InstructionRecycler.clear(Allocator);
225   OperandRecycler.clear(Allocator);
226   BasicBlockRecycler.clear(Allocator);
227   CodeViewAnnotations.clear();
228   VariableDbgInfos.clear();
229   if (RegInfo) {
230     RegInfo->~MachineRegisterInfo();
231     Allocator.Deallocate(RegInfo);
232   }
233   if (MFInfo) {
234     MFInfo->~MachineFunctionInfo();
235     Allocator.Deallocate(MFInfo);
236   }
237 
238   FrameInfo->~MachineFrameInfo();
239   Allocator.Deallocate(FrameInfo);
240 
241   ConstantPool->~MachineConstantPool();
242   Allocator.Deallocate(ConstantPool);
243 
244   if (JumpTableInfo) {
245     JumpTableInfo->~MachineJumpTableInfo();
246     Allocator.Deallocate(JumpTableInfo);
247   }
248 
249   if (WinEHInfo) {
250     WinEHInfo->~WinEHFuncInfo();
251     Allocator.Deallocate(WinEHInfo);
252   }
253 
254   if (WasmEHInfo) {
255     WasmEHInfo->~WasmEHFuncInfo();
256     Allocator.Deallocate(WasmEHInfo);
257   }
258 }
259 
260 const DataLayout &MachineFunction::getDataLayout() const {
261   return F.getParent()->getDataLayout();
262 }
263 
264 /// Get the JumpTableInfo for this function.
265 /// If it does not already exist, allocate one.
266 MachineJumpTableInfo *MachineFunction::
267 getOrCreateJumpTableInfo(unsigned EntryKind) {
268   if (JumpTableInfo) return JumpTableInfo;
269 
270   JumpTableInfo = new (Allocator)
271     MachineJumpTableInfo((MachineJumpTableInfo::JTEntryKind)EntryKind);
272   return JumpTableInfo;
273 }
274 
275 DenormalMode MachineFunction::getDenormalMode(const fltSemantics &FPType) const {
276   return F.getDenormalMode(FPType);
277 }
278 
279 /// Should we be emitting segmented stack stuff for the function
280 bool MachineFunction::shouldSplitStack() const {
281   return getFunction().hasFnAttribute("split-stack");
282 }
283 
284 LLVM_NODISCARD unsigned
285 MachineFunction::addFrameInst(const MCCFIInstruction &Inst) {
286   FrameInstructions.push_back(Inst);
287   return FrameInstructions.size() - 1;
288 }
289 
290 /// This discards all of the MachineBasicBlock numbers and recomputes them.
291 /// This guarantees that the MBB numbers are sequential, dense, and match the
292 /// ordering of the blocks within the function.  If a specific MachineBasicBlock
293 /// is specified, only that block and those after it are renumbered.
294 void MachineFunction::RenumberBlocks(MachineBasicBlock *MBB) {
295   if (empty()) { MBBNumbering.clear(); return; }
296   MachineFunction::iterator MBBI, E = end();
297   if (MBB == nullptr)
298     MBBI = begin();
299   else
300     MBBI = MBB->getIterator();
301 
302   // Figure out the block number this should have.
303   unsigned BlockNo = 0;
304   if (MBBI != begin())
305     BlockNo = std::prev(MBBI)->getNumber() + 1;
306 
307   for (; MBBI != E; ++MBBI, ++BlockNo) {
308     if (MBBI->getNumber() != (int)BlockNo) {
309       // Remove use of the old number.
310       if (MBBI->getNumber() != -1) {
311         assert(MBBNumbering[MBBI->getNumber()] == &*MBBI &&
312                "MBB number mismatch!");
313         MBBNumbering[MBBI->getNumber()] = nullptr;
314       }
315 
316       // If BlockNo is already taken, set that block's number to -1.
317       if (MBBNumbering[BlockNo])
318         MBBNumbering[BlockNo]->setNumber(-1);
319 
320       MBBNumbering[BlockNo] = &*MBBI;
321       MBBI->setNumber(BlockNo);
322     }
323   }
324 
325   // Okay, all the blocks are renumbered.  If we have compactified the block
326   // numbering, shrink MBBNumbering now.
327   assert(BlockNo <= MBBNumbering.size() && "Mismatch!");
328   MBBNumbering.resize(BlockNo);
329 }
330 
331 /// This method iterates over the basic blocks and assigns their IsBeginSection
332 /// and IsEndSection fields. This must be called after MBB layout is finalized
333 /// and the SectionID's are assigned to MBBs.
334 void MachineFunction::assignBeginEndSections() {
335   front().setIsBeginSection();
336   auto CurrentSectionID = front().getSectionID();
337   for (auto MBBI = std::next(begin()), E = end(); MBBI != E; ++MBBI) {
338     if (MBBI->getSectionID() == CurrentSectionID)
339       continue;
340     MBBI->setIsBeginSection();
341     std::prev(MBBI)->setIsEndSection();
342     CurrentSectionID = MBBI->getSectionID();
343   }
344   back().setIsEndSection();
345 }
346 
347 /// Allocate a new MachineInstr. Use this instead of `new MachineInstr'.
348 MachineInstr *MachineFunction::CreateMachineInstr(const MCInstrDesc &MCID,
349                                                   const DebugLoc &DL,
350                                                   bool NoImplicit) {
351   return new (InstructionRecycler.Allocate<MachineInstr>(Allocator))
352       MachineInstr(*this, MCID, DL, NoImplicit);
353 }
354 
355 /// Create a new MachineInstr which is a copy of the 'Orig' instruction,
356 /// identical in all ways except the instruction has no parent, prev, or next.
357 MachineInstr *
358 MachineFunction::CloneMachineInstr(const MachineInstr *Orig) {
359   return new (InstructionRecycler.Allocate<MachineInstr>(Allocator))
360              MachineInstr(*this, *Orig);
361 }
362 
363 MachineInstr &MachineFunction::CloneMachineInstrBundle(MachineBasicBlock &MBB,
364     MachineBasicBlock::iterator InsertBefore, const MachineInstr &Orig) {
365   MachineInstr *FirstClone = nullptr;
366   MachineBasicBlock::const_instr_iterator I = Orig.getIterator();
367   while (true) {
368     MachineInstr *Cloned = CloneMachineInstr(&*I);
369     MBB.insert(InsertBefore, Cloned);
370     if (FirstClone == nullptr) {
371       FirstClone = Cloned;
372     } else {
373       Cloned->bundleWithPred();
374     }
375 
376     if (!I->isBundledWithSucc())
377       break;
378     ++I;
379   }
380   // Copy over call site info to the cloned instruction if needed. If Orig is in
381   // a bundle, copyCallSiteInfo takes care of finding the call instruction in
382   // the bundle.
383   if (Orig.shouldUpdateCallSiteInfo())
384     copyCallSiteInfo(&Orig, FirstClone);
385   return *FirstClone;
386 }
387 
388 /// Delete the given MachineInstr.
389 ///
390 /// This function also serves as the MachineInstr destructor - the real
391 /// ~MachineInstr() destructor must be empty.
392 void
393 MachineFunction::DeleteMachineInstr(MachineInstr *MI) {
394   // Verify that a call site info is at valid state. This assertion should
395   // be triggered during the implementation of support for the
396   // call site info of a new architecture. If the assertion is triggered,
397   // back trace will tell where to insert a call to updateCallSiteInfo().
398   assert((!MI->isCandidateForCallSiteEntry() ||
399           CallSitesInfo.find(MI) == CallSitesInfo.end()) &&
400          "Call site info was not updated!");
401   // Strip it for parts. The operand array and the MI object itself are
402   // independently recyclable.
403   if (MI->Operands)
404     deallocateOperandArray(MI->CapOperands, MI->Operands);
405   // Don't call ~MachineInstr() which must be trivial anyway because
406   // ~MachineFunction drops whole lists of MachineInstrs wihout calling their
407   // destructors.
408   InstructionRecycler.Deallocate(Allocator, MI);
409 }
410 
411 /// Allocate a new MachineBasicBlock. Use this instead of
412 /// `new MachineBasicBlock'.
413 MachineBasicBlock *
414 MachineFunction::CreateMachineBasicBlock(const BasicBlock *bb) {
415   return new (BasicBlockRecycler.Allocate<MachineBasicBlock>(Allocator))
416              MachineBasicBlock(*this, bb);
417 }
418 
419 /// Delete the given MachineBasicBlock.
420 void
421 MachineFunction::DeleteMachineBasicBlock(MachineBasicBlock *MBB) {
422   assert(MBB->getParent() == this && "MBB parent mismatch!");
423   // Clean up any references to MBB in jump tables before deleting it.
424   if (JumpTableInfo)
425     JumpTableInfo->RemoveMBBFromJumpTables(MBB);
426   MBB->~MachineBasicBlock();
427   BasicBlockRecycler.Deallocate(Allocator, MBB);
428 }
429 
430 MachineMemOperand *MachineFunction::getMachineMemOperand(
431     MachinePointerInfo PtrInfo, MachineMemOperand::Flags f, uint64_t s,
432     Align base_alignment, const AAMDNodes &AAInfo, const MDNode *Ranges,
433     SyncScope::ID SSID, AtomicOrdering Ordering,
434     AtomicOrdering FailureOrdering) {
435   return new (Allocator)
436       MachineMemOperand(PtrInfo, f, s, base_alignment, AAInfo, Ranges,
437                         SSID, Ordering, FailureOrdering);
438 }
439 
440 MachineMemOperand *MachineFunction::getMachineMemOperand(
441     MachinePointerInfo PtrInfo, MachineMemOperand::Flags f, LLT MemTy,
442     Align base_alignment, const AAMDNodes &AAInfo, const MDNode *Ranges,
443     SyncScope::ID SSID, AtomicOrdering Ordering,
444     AtomicOrdering FailureOrdering) {
445   return new (Allocator)
446       MachineMemOperand(PtrInfo, f, MemTy, base_alignment, AAInfo, Ranges, SSID,
447                         Ordering, FailureOrdering);
448 }
449 
450 MachineMemOperand *MachineFunction::getMachineMemOperand(
451     const MachineMemOperand *MMO, const MachinePointerInfo &PtrInfo, uint64_t Size) {
452   return new (Allocator)
453       MachineMemOperand(PtrInfo, MMO->getFlags(), Size, MMO->getBaseAlign(),
454                         AAMDNodes(), nullptr, MMO->getSyncScopeID(),
455                         MMO->getSuccessOrdering(), MMO->getFailureOrdering());
456 }
457 
458 MachineMemOperand *MachineFunction::getMachineMemOperand(
459     const MachineMemOperand *MMO, const MachinePointerInfo &PtrInfo, LLT Ty) {
460   return new (Allocator)
461       MachineMemOperand(PtrInfo, MMO->getFlags(), Ty, MMO->getBaseAlign(),
462                         AAMDNodes(), nullptr, MMO->getSyncScopeID(),
463                         MMO->getSuccessOrdering(), MMO->getFailureOrdering());
464 }
465 
466 MachineMemOperand *
467 MachineFunction::getMachineMemOperand(const MachineMemOperand *MMO,
468                                       int64_t Offset, LLT Ty) {
469   const MachinePointerInfo &PtrInfo = MMO->getPointerInfo();
470 
471   // If there is no pointer value, the offset isn't tracked so we need to adjust
472   // the base alignment.
473   Align Alignment = PtrInfo.V.isNull()
474                         ? commonAlignment(MMO->getBaseAlign(), Offset)
475                         : MMO->getBaseAlign();
476 
477   // Do not preserve ranges, since we don't necessarily know what the high bits
478   // are anymore.
479   return new (Allocator) MachineMemOperand(
480       PtrInfo.getWithOffset(Offset), MMO->getFlags(), Ty, Alignment,
481       MMO->getAAInfo(), nullptr, MMO->getSyncScopeID(),
482       MMO->getSuccessOrdering(), MMO->getFailureOrdering());
483 }
484 
485 MachineMemOperand *
486 MachineFunction::getMachineMemOperand(const MachineMemOperand *MMO,
487                                       const AAMDNodes &AAInfo) {
488   MachinePointerInfo MPI = MMO->getValue() ?
489              MachinePointerInfo(MMO->getValue(), MMO->getOffset()) :
490              MachinePointerInfo(MMO->getPseudoValue(), MMO->getOffset());
491 
492   return new (Allocator) MachineMemOperand(
493       MPI, MMO->getFlags(), MMO->getSize(), MMO->getBaseAlign(), AAInfo,
494       MMO->getRanges(), MMO->getSyncScopeID(), MMO->getSuccessOrdering(),
495       MMO->getFailureOrdering());
496 }
497 
498 MachineMemOperand *
499 MachineFunction::getMachineMemOperand(const MachineMemOperand *MMO,
500                                       MachineMemOperand::Flags Flags) {
501   return new (Allocator) MachineMemOperand(
502       MMO->getPointerInfo(), Flags, MMO->getSize(), MMO->getBaseAlign(),
503       MMO->getAAInfo(), MMO->getRanges(), MMO->getSyncScopeID(),
504       MMO->getSuccessOrdering(), MMO->getFailureOrdering());
505 }
506 
507 MachineInstr::ExtraInfo *MachineFunction::createMIExtraInfo(
508     ArrayRef<MachineMemOperand *> MMOs, MCSymbol *PreInstrSymbol,
509     MCSymbol *PostInstrSymbol, MDNode *HeapAllocMarker) {
510   return MachineInstr::ExtraInfo::create(Allocator, MMOs, PreInstrSymbol,
511                                          PostInstrSymbol, HeapAllocMarker);
512 }
513 
514 const char *MachineFunction::createExternalSymbolName(StringRef Name) {
515   char *Dest = Allocator.Allocate<char>(Name.size() + 1);
516   llvm::copy(Name, Dest);
517   Dest[Name.size()] = 0;
518   return Dest;
519 }
520 
521 uint32_t *MachineFunction::allocateRegMask() {
522   unsigned NumRegs = getSubtarget().getRegisterInfo()->getNumRegs();
523   unsigned Size = MachineOperand::getRegMaskSize(NumRegs);
524   uint32_t *Mask = Allocator.Allocate<uint32_t>(Size);
525   memset(Mask, 0, Size * sizeof(Mask[0]));
526   return Mask;
527 }
528 
529 ArrayRef<int> MachineFunction::allocateShuffleMask(ArrayRef<int> Mask) {
530   int* AllocMask = Allocator.Allocate<int>(Mask.size());
531   copy(Mask, AllocMask);
532   return {AllocMask, Mask.size()};
533 }
534 
535 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
536 LLVM_DUMP_METHOD void MachineFunction::dump() const {
537   print(dbgs());
538 }
539 #endif
540 
541 StringRef MachineFunction::getName() const {
542   return getFunction().getName();
543 }
544 
545 void MachineFunction::print(raw_ostream &OS, const SlotIndexes *Indexes) const {
546   OS << "# Machine code for function " << getName() << ": ";
547   getProperties().print(OS);
548   OS << '\n';
549 
550   // Print Frame Information
551   FrameInfo->print(*this, OS);
552 
553   // Print JumpTable Information
554   if (JumpTableInfo)
555     JumpTableInfo->print(OS);
556 
557   // Print Constant Pool
558   ConstantPool->print(OS);
559 
560   const TargetRegisterInfo *TRI = getSubtarget().getRegisterInfo();
561 
562   if (RegInfo && !RegInfo->livein_empty()) {
563     OS << "Function Live Ins: ";
564     for (MachineRegisterInfo::livein_iterator
565          I = RegInfo->livein_begin(), E = RegInfo->livein_end(); I != E; ++I) {
566       OS << printReg(I->first, TRI);
567       if (I->second)
568         OS << " in " << printReg(I->second, TRI);
569       if (std::next(I) != E)
570         OS << ", ";
571     }
572     OS << '\n';
573   }
574 
575   ModuleSlotTracker MST(getFunction().getParent());
576   MST.incorporateFunction(getFunction());
577   for (const auto &BB : *this) {
578     OS << '\n';
579     // If we print the whole function, print it at its most verbose level.
580     BB.print(OS, MST, Indexes, /*IsStandalone=*/true);
581   }
582 
583   OS << "\n# End machine code for function " << getName() << ".\n\n";
584 }
585 
586 /// True if this function needs frame moves for debug or exceptions.
587 bool MachineFunction::needsFrameMoves() const {
588   return getMMI().hasDebugInfo() ||
589          getTarget().Options.ForceDwarfFrameSection ||
590          F.needsUnwindTableEntry();
591 }
592 
593 namespace llvm {
594 
595   template<>
596   struct DOTGraphTraits<const MachineFunction*> : public DefaultDOTGraphTraits {
597     DOTGraphTraits(bool isSimple = false) : DefaultDOTGraphTraits(isSimple) {}
598 
599     static std::string getGraphName(const MachineFunction *F) {
600       return ("CFG for '" + F->getName() + "' function").str();
601     }
602 
603     std::string getNodeLabel(const MachineBasicBlock *Node,
604                              const MachineFunction *Graph) {
605       std::string OutStr;
606       {
607         raw_string_ostream OSS(OutStr);
608 
609         if (isSimple()) {
610           OSS << printMBBReference(*Node);
611           if (const BasicBlock *BB = Node->getBasicBlock())
612             OSS << ": " << BB->getName();
613         } else
614           Node->print(OSS);
615       }
616 
617       if (OutStr[0] == '\n') OutStr.erase(OutStr.begin());
618 
619       // Process string output to make it nicer...
620       for (unsigned i = 0; i != OutStr.length(); ++i)
621         if (OutStr[i] == '\n') {                            // Left justify
622           OutStr[i] = '\\';
623           OutStr.insert(OutStr.begin()+i+1, 'l');
624         }
625       return OutStr;
626     }
627   };
628 
629 } // end namespace llvm
630 
631 void MachineFunction::viewCFG() const
632 {
633 #ifndef NDEBUG
634   ViewGraph(this, "mf" + getName());
635 #else
636   errs() << "MachineFunction::viewCFG is only available in debug builds on "
637          << "systems with Graphviz or gv!\n";
638 #endif // NDEBUG
639 }
640 
641 void MachineFunction::viewCFGOnly() const
642 {
643 #ifndef NDEBUG
644   ViewGraph(this, "mf" + getName(), true);
645 #else
646   errs() << "MachineFunction::viewCFGOnly is only available in debug builds on "
647          << "systems with Graphviz or gv!\n";
648 #endif // NDEBUG
649 }
650 
651 /// Add the specified physical register as a live-in value and
652 /// create a corresponding virtual register for it.
653 Register MachineFunction::addLiveIn(MCRegister PReg,
654                                     const TargetRegisterClass *RC) {
655   MachineRegisterInfo &MRI = getRegInfo();
656   Register VReg = MRI.getLiveInVirtReg(PReg);
657   if (VReg) {
658     const TargetRegisterClass *VRegRC = MRI.getRegClass(VReg);
659     (void)VRegRC;
660     // A physical register can be added several times.
661     // Between two calls, the register class of the related virtual register
662     // may have been constrained to match some operation constraints.
663     // In that case, check that the current register class includes the
664     // physical register and is a sub class of the specified RC.
665     assert((VRegRC == RC || (VRegRC->contains(PReg) &&
666                              RC->hasSubClassEq(VRegRC))) &&
667             "Register class mismatch!");
668     return VReg;
669   }
670   VReg = MRI.createVirtualRegister(RC);
671   MRI.addLiveIn(PReg, VReg);
672   return VReg;
673 }
674 
675 /// Return the MCSymbol for the specified non-empty jump table.
676 /// If isLinkerPrivate is specified, an 'l' label is returned, otherwise a
677 /// normal 'L' label is returned.
678 MCSymbol *MachineFunction::getJTISymbol(unsigned JTI, MCContext &Ctx,
679                                         bool isLinkerPrivate) const {
680   const DataLayout &DL = getDataLayout();
681   assert(JumpTableInfo && "No jump tables");
682   assert(JTI < JumpTableInfo->getJumpTables().size() && "Invalid JTI!");
683 
684   StringRef Prefix = isLinkerPrivate ? DL.getLinkerPrivateGlobalPrefix()
685                                      : DL.getPrivateGlobalPrefix();
686   SmallString<60> Name;
687   raw_svector_ostream(Name)
688     << Prefix << "JTI" << getFunctionNumber() << '_' << JTI;
689   return Ctx.getOrCreateSymbol(Name);
690 }
691 
692 /// Return a function-local symbol to represent the PIC base.
693 MCSymbol *MachineFunction::getPICBaseSymbol() const {
694   const DataLayout &DL = getDataLayout();
695   return Ctx.getOrCreateSymbol(Twine(DL.getPrivateGlobalPrefix()) +
696                                Twine(getFunctionNumber()) + "$pb");
697 }
698 
699 /// \name Exception Handling
700 /// \{
701 
702 LandingPadInfo &
703 MachineFunction::getOrCreateLandingPadInfo(MachineBasicBlock *LandingPad) {
704   unsigned N = LandingPads.size();
705   for (unsigned i = 0; i < N; ++i) {
706     LandingPadInfo &LP = LandingPads[i];
707     if (LP.LandingPadBlock == LandingPad)
708       return LP;
709   }
710 
711   LandingPads.push_back(LandingPadInfo(LandingPad));
712   return LandingPads[N];
713 }
714 
715 void MachineFunction::addInvoke(MachineBasicBlock *LandingPad,
716                                 MCSymbol *BeginLabel, MCSymbol *EndLabel) {
717   LandingPadInfo &LP = getOrCreateLandingPadInfo(LandingPad);
718   LP.BeginLabels.push_back(BeginLabel);
719   LP.EndLabels.push_back(EndLabel);
720 }
721 
722 MCSymbol *MachineFunction::addLandingPad(MachineBasicBlock *LandingPad) {
723   MCSymbol *LandingPadLabel = Ctx.createTempSymbol();
724   LandingPadInfo &LP = getOrCreateLandingPadInfo(LandingPad);
725   LP.LandingPadLabel = LandingPadLabel;
726 
727   const Instruction *FirstI = LandingPad->getBasicBlock()->getFirstNonPHI();
728   if (const auto *LPI = dyn_cast<LandingPadInst>(FirstI)) {
729     if (const auto *PF =
730             dyn_cast<Function>(F.getPersonalityFn()->stripPointerCasts()))
731       getMMI().addPersonality(PF);
732 
733     if (LPI->isCleanup())
734       addCleanup(LandingPad);
735 
736     // FIXME: New EH - Add the clauses in reverse order. This isn't 100%
737     //        correct, but we need to do it this way because of how the DWARF EH
738     //        emitter processes the clauses.
739     for (unsigned I = LPI->getNumClauses(); I != 0; --I) {
740       Value *Val = LPI->getClause(I - 1);
741       if (LPI->isCatch(I - 1)) {
742         addCatchTypeInfo(LandingPad,
743                          dyn_cast<GlobalValue>(Val->stripPointerCasts()));
744       } else {
745         // Add filters in a list.
746         auto *CVal = cast<Constant>(Val);
747         SmallVector<const GlobalValue *, 4> FilterList;
748         for (User::op_iterator II = CVal->op_begin(), IE = CVal->op_end();
749              II != IE; ++II)
750           FilterList.push_back(cast<GlobalValue>((*II)->stripPointerCasts()));
751 
752         addFilterTypeInfo(LandingPad, FilterList);
753       }
754     }
755 
756   } else if (const auto *CPI = dyn_cast<CatchPadInst>(FirstI)) {
757     for (unsigned I = CPI->getNumArgOperands(); I != 0; --I) {
758       Value *TypeInfo = CPI->getArgOperand(I - 1)->stripPointerCasts();
759       addCatchTypeInfo(LandingPad, dyn_cast<GlobalValue>(TypeInfo));
760     }
761 
762   } else {
763     assert(isa<CleanupPadInst>(FirstI) && "Invalid landingpad!");
764   }
765 
766   return LandingPadLabel;
767 }
768 
769 void MachineFunction::addCatchTypeInfo(MachineBasicBlock *LandingPad,
770                                        ArrayRef<const GlobalValue *> TyInfo) {
771   LandingPadInfo &LP = getOrCreateLandingPadInfo(LandingPad);
772   for (unsigned N = TyInfo.size(); N; --N)
773     LP.TypeIds.push_back(getTypeIDFor(TyInfo[N - 1]));
774 }
775 
776 void MachineFunction::addFilterTypeInfo(MachineBasicBlock *LandingPad,
777                                         ArrayRef<const GlobalValue *> TyInfo) {
778   LandingPadInfo &LP = getOrCreateLandingPadInfo(LandingPad);
779   std::vector<unsigned> IdsInFilter(TyInfo.size());
780   for (unsigned I = 0, E = TyInfo.size(); I != E; ++I)
781     IdsInFilter[I] = getTypeIDFor(TyInfo[I]);
782   LP.TypeIds.push_back(getFilterIDFor(IdsInFilter));
783 }
784 
785 void MachineFunction::tidyLandingPads(DenseMap<MCSymbol *, uintptr_t> *LPMap,
786                                       bool TidyIfNoBeginLabels) {
787   for (unsigned i = 0; i != LandingPads.size(); ) {
788     LandingPadInfo &LandingPad = LandingPads[i];
789     if (LandingPad.LandingPadLabel &&
790         !LandingPad.LandingPadLabel->isDefined() &&
791         (!LPMap || (*LPMap)[LandingPad.LandingPadLabel] == 0))
792       LandingPad.LandingPadLabel = nullptr;
793 
794     // Special case: we *should* emit LPs with null LP MBB. This indicates
795     // "nounwind" case.
796     if (!LandingPad.LandingPadLabel && LandingPad.LandingPadBlock) {
797       LandingPads.erase(LandingPads.begin() + i);
798       continue;
799     }
800 
801     if (TidyIfNoBeginLabels) {
802       for (unsigned j = 0, e = LandingPads[i].BeginLabels.size(); j != e; ++j) {
803         MCSymbol *BeginLabel = LandingPad.BeginLabels[j];
804         MCSymbol *EndLabel = LandingPad.EndLabels[j];
805         if ((BeginLabel->isDefined() || (LPMap && (*LPMap)[BeginLabel] != 0)) &&
806             (EndLabel->isDefined() || (LPMap && (*LPMap)[EndLabel] != 0)))
807           continue;
808 
809         LandingPad.BeginLabels.erase(LandingPad.BeginLabels.begin() + j);
810         LandingPad.EndLabels.erase(LandingPad.EndLabels.begin() + j);
811         --j;
812         --e;
813       }
814 
815       // Remove landing pads with no try-ranges.
816       if (LandingPads[i].BeginLabels.empty()) {
817         LandingPads.erase(LandingPads.begin() + i);
818         continue;
819       }
820     }
821 
822     // If there is no landing pad, ensure that the list of typeids is empty.
823     // If the only typeid is a cleanup, this is the same as having no typeids.
824     if (!LandingPad.LandingPadBlock ||
825         (LandingPad.TypeIds.size() == 1 && !LandingPad.TypeIds[0]))
826       LandingPad.TypeIds.clear();
827     ++i;
828   }
829 }
830 
831 void MachineFunction::addCleanup(MachineBasicBlock *LandingPad) {
832   LandingPadInfo &LP = getOrCreateLandingPadInfo(LandingPad);
833   LP.TypeIds.push_back(0);
834 }
835 
836 void MachineFunction::addSEHCatchHandler(MachineBasicBlock *LandingPad,
837                                          const Function *Filter,
838                                          const BlockAddress *RecoverBA) {
839   LandingPadInfo &LP = getOrCreateLandingPadInfo(LandingPad);
840   SEHHandler Handler;
841   Handler.FilterOrFinally = Filter;
842   Handler.RecoverBA = RecoverBA;
843   LP.SEHHandlers.push_back(Handler);
844 }
845 
846 void MachineFunction::addSEHCleanupHandler(MachineBasicBlock *LandingPad,
847                                            const Function *Cleanup) {
848   LandingPadInfo &LP = getOrCreateLandingPadInfo(LandingPad);
849   SEHHandler Handler;
850   Handler.FilterOrFinally = Cleanup;
851   Handler.RecoverBA = nullptr;
852   LP.SEHHandlers.push_back(Handler);
853 }
854 
855 void MachineFunction::setCallSiteLandingPad(MCSymbol *Sym,
856                                             ArrayRef<unsigned> Sites) {
857   LPadToCallSiteMap[Sym].append(Sites.begin(), Sites.end());
858 }
859 
860 unsigned MachineFunction::getTypeIDFor(const GlobalValue *TI) {
861   for (unsigned i = 0, N = TypeInfos.size(); i != N; ++i)
862     if (TypeInfos[i] == TI) return i + 1;
863 
864   TypeInfos.push_back(TI);
865   return TypeInfos.size();
866 }
867 
868 int MachineFunction::getFilterIDFor(std::vector<unsigned> &TyIds) {
869   // If the new filter coincides with the tail of an existing filter, then
870   // re-use the existing filter.  Folding filters more than this requires
871   // re-ordering filters and/or their elements - probably not worth it.
872   for (unsigned i : FilterEnds) {
873     unsigned j = TyIds.size();
874 
875     while (i && j)
876       if (FilterIds[--i] != TyIds[--j])
877         goto try_next;
878 
879     if (!j)
880       // The new filter coincides with range [i, end) of the existing filter.
881       return -(1 + i);
882 
883 try_next:;
884   }
885 
886   // Add the new filter.
887   int FilterID = -(1 + FilterIds.size());
888   FilterIds.reserve(FilterIds.size() + TyIds.size() + 1);
889   llvm::append_range(FilterIds, TyIds);
890   FilterEnds.push_back(FilterIds.size());
891   FilterIds.push_back(0); // terminator
892   return FilterID;
893 }
894 
895 MachineFunction::CallSiteInfoMap::iterator
896 MachineFunction::getCallSiteInfo(const MachineInstr *MI) {
897   assert(MI->isCandidateForCallSiteEntry() &&
898          "Call site info refers only to call (MI) candidates");
899 
900   if (!Target.Options.EmitCallSiteInfo)
901     return CallSitesInfo.end();
902   return CallSitesInfo.find(MI);
903 }
904 
905 /// Return the call machine instruction or find a call within bundle.
906 static const MachineInstr *getCallInstr(const MachineInstr *MI) {
907   if (!MI->isBundle())
908     return MI;
909 
910   for (auto &BMI : make_range(getBundleStart(MI->getIterator()),
911                               getBundleEnd(MI->getIterator())))
912     if (BMI.isCandidateForCallSiteEntry())
913       return &BMI;
914 
915   llvm_unreachable("Unexpected bundle without a call site candidate");
916 }
917 
918 void MachineFunction::eraseCallSiteInfo(const MachineInstr *MI) {
919   assert(MI->shouldUpdateCallSiteInfo() &&
920          "Call site info refers only to call (MI) candidates or "
921          "candidates inside bundles");
922 
923   const MachineInstr *CallMI = getCallInstr(MI);
924   CallSiteInfoMap::iterator CSIt = getCallSiteInfo(CallMI);
925   if (CSIt == CallSitesInfo.end())
926     return;
927   CallSitesInfo.erase(CSIt);
928 }
929 
930 void MachineFunction::copyCallSiteInfo(const MachineInstr *Old,
931                                        const MachineInstr *New) {
932   assert(Old->shouldUpdateCallSiteInfo() &&
933          "Call site info refers only to call (MI) candidates or "
934          "candidates inside bundles");
935 
936   if (!New->isCandidateForCallSiteEntry())
937     return eraseCallSiteInfo(Old);
938 
939   const MachineInstr *OldCallMI = getCallInstr(Old);
940   CallSiteInfoMap::iterator CSIt = getCallSiteInfo(OldCallMI);
941   if (CSIt == CallSitesInfo.end())
942     return;
943 
944   CallSiteInfo CSInfo = CSIt->second;
945   CallSitesInfo[New] = CSInfo;
946 }
947 
948 void MachineFunction::moveCallSiteInfo(const MachineInstr *Old,
949                                        const MachineInstr *New) {
950   assert(Old->shouldUpdateCallSiteInfo() &&
951          "Call site info refers only to call (MI) candidates or "
952          "candidates inside bundles");
953 
954   if (!New->isCandidateForCallSiteEntry())
955     return eraseCallSiteInfo(Old);
956 
957   const MachineInstr *OldCallMI = getCallInstr(Old);
958   CallSiteInfoMap::iterator CSIt = getCallSiteInfo(OldCallMI);
959   if (CSIt == CallSitesInfo.end())
960     return;
961 
962   CallSiteInfo CSInfo = std::move(CSIt->second);
963   CallSitesInfo.erase(CSIt);
964   CallSitesInfo[New] = CSInfo;
965 }
966 
967 void MachineFunction::setDebugInstrNumberingCount(unsigned Num) {
968   DebugInstrNumberingCount = Num;
969 }
970 
971 void MachineFunction::makeDebugValueSubstitution(DebugInstrOperandPair A,
972                                                  DebugInstrOperandPair B,
973                                                  unsigned Subreg) {
974   // Catch any accidental self-loops.
975   assert(A.first != B.first);
976   DebugValueSubstitutions.push_back({A, B, Subreg});
977 }
978 
979 void MachineFunction::substituteDebugValuesForInst(const MachineInstr &Old,
980                                                    MachineInstr &New,
981                                                    unsigned MaxOperand) {
982   // If the Old instruction wasn't tracked at all, there is no work to do.
983   unsigned OldInstrNum = Old.peekDebugInstrNum();
984   if (!OldInstrNum)
985     return;
986 
987   // Iterate over all operands looking for defs to create substitutions for.
988   // Avoid creating new instr numbers unless we create a new substitution.
989   // While this has no functional effect, it risks confusing someone reading
990   // MIR output.
991   // Examine all the operands, or the first N specified by the caller.
992   MaxOperand = std::min(MaxOperand, Old.getNumOperands());
993   for (unsigned int I = 0; I < MaxOperand; ++I) {
994     const auto &OldMO = Old.getOperand(I);
995     auto &NewMO = New.getOperand(I);
996     (void)NewMO;
997 
998     if (!OldMO.isReg() || !OldMO.isDef())
999       continue;
1000     assert(NewMO.isDef());
1001 
1002     unsigned NewInstrNum = New.getDebugInstrNum();
1003     makeDebugValueSubstitution(std::make_pair(OldInstrNum, I),
1004                                std::make_pair(NewInstrNum, I));
1005   }
1006 }
1007 
1008 auto MachineFunction::salvageCopySSA(MachineInstr &MI)
1009     -> DebugInstrOperandPair {
1010   MachineRegisterInfo &MRI = getRegInfo();
1011   const TargetRegisterInfo &TRI = *MRI.getTargetRegisterInfo();
1012   const TargetInstrInfo &TII = *getSubtarget().getInstrInfo();
1013 
1014   // Chase the value read by a copy-like instruction back to the instruction
1015   // that ultimately _defines_ that value. This may pass:
1016   //  * Through multiple intermediate copies, including subregister moves /
1017   //    copies,
1018   //  * Copies from physical registers that must then be traced back to the
1019   //    defining instruction,
1020   //  * Or, physical registers may be live-in to (only) the entry block, which
1021   //    requires a DBG_PHI to be created.
1022   // We can pursue this problem in that order: trace back through copies,
1023   // optionally through a physical register, to a defining instruction. We
1024   // should never move from physreg to vreg. As we're still in SSA form, no need
1025   // to worry about partial definitions of registers.
1026 
1027   // Helper lambda to interpret a copy-like instruction. Takes instruction,
1028   // returns the register read and any subregister identifying which part is
1029   // read.
1030   auto GetRegAndSubreg =
1031       [&](const MachineInstr &Cpy) -> std::pair<Register, unsigned> {
1032     Register NewReg, OldReg;
1033     unsigned SubReg;
1034     if (Cpy.isCopy()) {
1035       OldReg = Cpy.getOperand(0).getReg();
1036       NewReg = Cpy.getOperand(1).getReg();
1037       SubReg = Cpy.getOperand(1).getSubReg();
1038     } else if (Cpy.isSubregToReg()) {
1039       OldReg = Cpy.getOperand(0).getReg();
1040       NewReg = Cpy.getOperand(2).getReg();
1041       SubReg = Cpy.getOperand(3).getImm();
1042     } else {
1043       auto CopyDetails = *TII.isCopyInstr(Cpy);
1044       const MachineOperand &Src = *CopyDetails.Source;
1045       const MachineOperand &Dest = *CopyDetails.Destination;
1046       OldReg = Dest.getReg();
1047       NewReg = Src.getReg();
1048       SubReg = Src.getSubReg();
1049     }
1050 
1051     return {NewReg, SubReg};
1052   };
1053 
1054   // First seek either the defining instruction, or a copy from a physreg.
1055   // During search, the current state is the current copy instruction, and which
1056   // register we've read. Accumulate qualifying subregisters into SubregsSeen;
1057   // deal with those later.
1058   auto State = GetRegAndSubreg(MI);
1059   auto CurInst = MI.getIterator();
1060   SmallVector<unsigned, 4> SubregsSeen;
1061   while (true) {
1062     // If we've found a copy from a physreg, first portion of search is over.
1063     if (!State.first.isVirtual())
1064       break;
1065 
1066     // Record any subregister qualifier.
1067     if (State.second)
1068       SubregsSeen.push_back(State.second);
1069 
1070     assert(MRI.hasOneDef(State.first));
1071     MachineInstr &Inst = *MRI.def_begin(State.first)->getParent();
1072     CurInst = Inst.getIterator();
1073 
1074     // Any non-copy instruction is the defining instruction we're seeking.
1075     if (!Inst.isCopyLike() && !TII.isCopyInstr(Inst))
1076       break;
1077     State = GetRegAndSubreg(Inst);
1078   };
1079 
1080   // Helper lambda to apply additional subregister substitutions to a known
1081   // instruction/operand pair. Adds new (fake) substitutions so that we can
1082   // record the subregister. FIXME: this isn't very space efficient if multiple
1083   // values are tracked back through the same copies; cache something later.
1084   auto ApplySubregisters =
1085       [&](DebugInstrOperandPair P) -> DebugInstrOperandPair {
1086     for (unsigned Subreg : reverse(SubregsSeen)) {
1087       // Fetch a new instruction number, not attached to an actual instruction.
1088       unsigned NewInstrNumber = getNewDebugInstrNum();
1089       // Add a substitution from the "new" number to the known one, with a
1090       // qualifying subreg.
1091       makeDebugValueSubstitution({NewInstrNumber, 0}, P, Subreg);
1092       // Return the new number; to find the underlying value, consumers need to
1093       // deal with the qualifying subreg.
1094       P = {NewInstrNumber, 0};
1095     }
1096     return P;
1097   };
1098 
1099   // If we managed to find the defining instruction after COPYs, return an
1100   // instruction / operand pair after adding subregister qualifiers.
1101   if (State.first.isVirtual()) {
1102     // Virtual register def -- we can just look up where this happens.
1103     MachineInstr *Inst = MRI.def_begin(State.first)->getParent();
1104     for (auto &MO : Inst->operands()) {
1105       if (!MO.isReg() || !MO.isDef() || MO.getReg() != State.first)
1106         continue;
1107       return ApplySubregisters(
1108           {Inst->getDebugInstrNum(), Inst->getOperandNo(&MO)});
1109     }
1110 
1111     llvm_unreachable("Vreg def with no corresponding operand?");
1112   }
1113 
1114   // Our search ended in a copy from a physreg: walk back up the function
1115   // looking for whatever defines the physreg.
1116   assert(CurInst->isCopyLike() || TII.isCopyInstr(*CurInst));
1117   State = GetRegAndSubreg(*CurInst);
1118   Register RegToSeek = State.first;
1119 
1120   auto RMII = CurInst->getReverseIterator();
1121   auto PrevInstrs = make_range(RMII, CurInst->getParent()->instr_rend());
1122   for (auto &ToExamine : PrevInstrs) {
1123     for (auto &MO : ToExamine.operands()) {
1124       // Test for operand that defines something aliasing RegToSeek.
1125       if (!MO.isReg() || !MO.isDef() ||
1126           !TRI.regsOverlap(RegToSeek, MO.getReg()))
1127         continue;
1128 
1129       return ApplySubregisters(
1130           {ToExamine.getDebugInstrNum(), ToExamine.getOperandNo(&MO)});
1131     }
1132   }
1133 
1134   MachineBasicBlock &InsertBB = *CurInst->getParent();
1135 
1136   // We reached the start of the block before finding a defining instruction.
1137   // It could be from a constant register, otherwise it must be an argument.
1138   if (TRI.isConstantPhysReg(State.first)) {
1139     // We can produce a DBG_PHI that identifies the constant physreg. Doesn't
1140     // matter where we put it, as it's constant valued.
1141     assert(CurInst->isCopy());
1142   } else if (State.first == TRI.getFrameRegister(*this)) {
1143     // LLVM IR is allowed to read the framepointer by calling a
1144     // llvm.frameaddress.* intrinsic. We can support this by emitting a
1145     // DBG_PHI $fp. This isn't ideal, because it extends the behaviours /
1146     // position that DBG_PHIs appear at, limiting what can be done later.
1147     // TODO: see if there's a better way of expressing these variable
1148     // locations.
1149     ;
1150   } else {
1151     // Assert that this is the entry block. If it isn't, then there is some
1152     // code construct we don't recognise that deals with physregs across
1153     // blocks.
1154     assert(!State.first.isVirtual());
1155     assert(&*InsertBB.getParent()->begin() == &InsertBB);
1156   }
1157 
1158   // Create DBG_PHI for specified physreg.
1159   auto Builder = BuildMI(InsertBB, InsertBB.getFirstNonPHI(), DebugLoc(),
1160                          TII.get(TargetOpcode::DBG_PHI));
1161   Builder.addReg(State.first, RegState::Debug);
1162   unsigned NewNum = getNewDebugInstrNum();
1163   Builder.addImm(NewNum);
1164   return ApplySubregisters({NewNum, 0u});
1165 }
1166 
1167 void MachineFunction::finalizeDebugInstrRefs() {
1168   auto *TII = getSubtarget().getInstrInfo();
1169 
1170   auto MakeDbgValue = [&](MachineInstr &MI) {
1171     const MCInstrDesc &RefII = TII->get(TargetOpcode::DBG_VALUE);
1172     MI.setDesc(RefII);
1173     MI.getOperand(1).ChangeToRegister(0, false);
1174     MI.getOperand(0).setIsDebug();
1175   };
1176 
1177   if (!getTarget().Options.ValueTrackingVariableLocations)
1178     return;
1179 
1180   for (auto &MBB : *this) {
1181     for (auto &MI : MBB) {
1182       if (!MI.isDebugRef() || !MI.getOperand(0).isReg())
1183         continue;
1184 
1185       Register Reg = MI.getOperand(0).getReg();
1186 
1187       // Some vregs can be deleted as redundant in the meantime. Mark those
1188       // as DBG_VALUE $noreg.
1189       if (Reg == 0) {
1190         MakeDbgValue(MI);
1191         continue;
1192       }
1193 
1194       assert(Reg.isVirtual());
1195       MachineInstr &DefMI = *RegInfo->def_instr_begin(Reg);
1196       assert(RegInfo->hasOneDef(Reg));
1197 
1198       // If we've found a copy-like instruction, follow it back to the
1199       // instruction that defines the source value, see salvageCopySSA docs
1200       // for why this is important.
1201       if (DefMI.isCopyLike() || TII->isCopyInstr(DefMI)) {
1202         auto Result = salvageCopySSA(DefMI);
1203         MI.getOperand(0).ChangeToImmediate(Result.first);
1204         MI.getOperand(1).setImm(Result.second);
1205       } else {
1206         // Otherwise, identify the operand number that the VReg refers to.
1207         unsigned OperandIdx = 0;
1208         for (const auto &MO : DefMI.operands()) {
1209           if (MO.isReg() && MO.isDef() && MO.getReg() == Reg)
1210             break;
1211           ++OperandIdx;
1212         }
1213         assert(OperandIdx < DefMI.getNumOperands());
1214 
1215         // Morph this instr ref to point at the given instruction and operand.
1216         unsigned ID = DefMI.getDebugInstrNum();
1217         MI.getOperand(0).ChangeToImmediate(ID);
1218         MI.getOperand(1).setImm(OperandIdx);
1219       }
1220     }
1221   }
1222 }
1223 
1224 /// \}
1225 
1226 //===----------------------------------------------------------------------===//
1227 //  MachineJumpTableInfo implementation
1228 //===----------------------------------------------------------------------===//
1229 
1230 /// Return the size of each entry in the jump table.
1231 unsigned MachineJumpTableInfo::getEntrySize(const DataLayout &TD) const {
1232   // The size of a jump table entry is 4 bytes unless the entry is just the
1233   // address of a block, in which case it is the pointer size.
1234   switch (getEntryKind()) {
1235   case MachineJumpTableInfo::EK_BlockAddress:
1236     return TD.getPointerSize();
1237   case MachineJumpTableInfo::EK_GPRel64BlockAddress:
1238     return 8;
1239   case MachineJumpTableInfo::EK_GPRel32BlockAddress:
1240   case MachineJumpTableInfo::EK_LabelDifference32:
1241   case MachineJumpTableInfo::EK_Custom32:
1242     return 4;
1243   case MachineJumpTableInfo::EK_Inline:
1244     return 0;
1245   }
1246   llvm_unreachable("Unknown jump table encoding!");
1247 }
1248 
1249 /// Return the alignment of each entry in the jump table.
1250 unsigned MachineJumpTableInfo::getEntryAlignment(const DataLayout &TD) const {
1251   // The alignment of a jump table entry is the alignment of int32 unless the
1252   // entry is just the address of a block, in which case it is the pointer
1253   // alignment.
1254   switch (getEntryKind()) {
1255   case MachineJumpTableInfo::EK_BlockAddress:
1256     return TD.getPointerABIAlignment(0).value();
1257   case MachineJumpTableInfo::EK_GPRel64BlockAddress:
1258     return TD.getABIIntegerTypeAlignment(64).value();
1259   case MachineJumpTableInfo::EK_GPRel32BlockAddress:
1260   case MachineJumpTableInfo::EK_LabelDifference32:
1261   case MachineJumpTableInfo::EK_Custom32:
1262     return TD.getABIIntegerTypeAlignment(32).value();
1263   case MachineJumpTableInfo::EK_Inline:
1264     return 1;
1265   }
1266   llvm_unreachable("Unknown jump table encoding!");
1267 }
1268 
1269 /// Create a new jump table entry in the jump table info.
1270 unsigned MachineJumpTableInfo::createJumpTableIndex(
1271                                const std::vector<MachineBasicBlock*> &DestBBs) {
1272   assert(!DestBBs.empty() && "Cannot create an empty jump table!");
1273   JumpTables.push_back(MachineJumpTableEntry(DestBBs));
1274   return JumpTables.size()-1;
1275 }
1276 
1277 /// If Old is the target of any jump tables, update the jump tables to branch
1278 /// to New instead.
1279 bool MachineJumpTableInfo::ReplaceMBBInJumpTables(MachineBasicBlock *Old,
1280                                                   MachineBasicBlock *New) {
1281   assert(Old != New && "Not making a change?");
1282   bool MadeChange = false;
1283   for (size_t i = 0, e = JumpTables.size(); i != e; ++i)
1284     ReplaceMBBInJumpTable(i, Old, New);
1285   return MadeChange;
1286 }
1287 
1288 /// If MBB is present in any jump tables, remove it.
1289 bool MachineJumpTableInfo::RemoveMBBFromJumpTables(MachineBasicBlock *MBB) {
1290   bool MadeChange = false;
1291   for (MachineJumpTableEntry &JTE : JumpTables) {
1292     auto removeBeginItr = std::remove(JTE.MBBs.begin(), JTE.MBBs.end(), MBB);
1293     MadeChange |= (removeBeginItr != JTE.MBBs.end());
1294     JTE.MBBs.erase(removeBeginItr, JTE.MBBs.end());
1295   }
1296   return MadeChange;
1297 }
1298 
1299 /// If Old is a target of the jump tables, update the jump table to branch to
1300 /// New instead.
1301 bool MachineJumpTableInfo::ReplaceMBBInJumpTable(unsigned Idx,
1302                                                  MachineBasicBlock *Old,
1303                                                  MachineBasicBlock *New) {
1304   assert(Old != New && "Not making a change?");
1305   bool MadeChange = false;
1306   MachineJumpTableEntry &JTE = JumpTables[Idx];
1307   for (size_t j = 0, e = JTE.MBBs.size(); j != e; ++j)
1308     if (JTE.MBBs[j] == Old) {
1309       JTE.MBBs[j] = New;
1310       MadeChange = true;
1311     }
1312   return MadeChange;
1313 }
1314 
1315 void MachineJumpTableInfo::print(raw_ostream &OS) const {
1316   if (JumpTables.empty()) return;
1317 
1318   OS << "Jump Tables:\n";
1319 
1320   for (unsigned i = 0, e = JumpTables.size(); i != e; ++i) {
1321     OS << printJumpTableEntryReference(i) << ':';
1322     for (unsigned j = 0, f = JumpTables[i].MBBs.size(); j != f; ++j)
1323       OS << ' ' << printMBBReference(*JumpTables[i].MBBs[j]);
1324     if (i != e)
1325       OS << '\n';
1326   }
1327 
1328   OS << '\n';
1329 }
1330 
1331 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
1332 LLVM_DUMP_METHOD void MachineJumpTableInfo::dump() const { print(dbgs()); }
1333 #endif
1334 
1335 Printable llvm::printJumpTableEntryReference(unsigned Idx) {
1336   return Printable([Idx](raw_ostream &OS) { OS << "%jump-table." << Idx; });
1337 }
1338 
1339 //===----------------------------------------------------------------------===//
1340 //  MachineConstantPool implementation
1341 //===----------------------------------------------------------------------===//
1342 
1343 void MachineConstantPoolValue::anchor() {}
1344 
1345 unsigned MachineConstantPoolValue::getSizeInBytes(const DataLayout &DL) const {
1346   return DL.getTypeAllocSize(Ty);
1347 }
1348 
1349 unsigned MachineConstantPoolEntry::getSizeInBytes(const DataLayout &DL) const {
1350   if (isMachineConstantPoolEntry())
1351     return Val.MachineCPVal->getSizeInBytes(DL);
1352   return DL.getTypeAllocSize(Val.ConstVal->getType());
1353 }
1354 
1355 bool MachineConstantPoolEntry::needsRelocation() const {
1356   if (isMachineConstantPoolEntry())
1357     return true;
1358   return Val.ConstVal->needsDynamicRelocation();
1359 }
1360 
1361 SectionKind
1362 MachineConstantPoolEntry::getSectionKind(const DataLayout *DL) const {
1363   if (needsRelocation())
1364     return SectionKind::getReadOnlyWithRel();
1365   switch (getSizeInBytes(*DL)) {
1366   case 4:
1367     return SectionKind::getMergeableConst4();
1368   case 8:
1369     return SectionKind::getMergeableConst8();
1370   case 16:
1371     return SectionKind::getMergeableConst16();
1372   case 32:
1373     return SectionKind::getMergeableConst32();
1374   default:
1375     return SectionKind::getReadOnly();
1376   }
1377 }
1378 
1379 MachineConstantPool::~MachineConstantPool() {
1380   // A constant may be a member of both Constants and MachineCPVsSharingEntries,
1381   // so keep track of which we've deleted to avoid double deletions.
1382   DenseSet<MachineConstantPoolValue*> Deleted;
1383   for (unsigned i = 0, e = Constants.size(); i != e; ++i)
1384     if (Constants[i].isMachineConstantPoolEntry()) {
1385       Deleted.insert(Constants[i].Val.MachineCPVal);
1386       delete Constants[i].Val.MachineCPVal;
1387     }
1388   for (MachineConstantPoolValue *CPV : MachineCPVsSharingEntries) {
1389     if (Deleted.count(CPV) == 0)
1390       delete CPV;
1391   }
1392 }
1393 
1394 /// Test whether the given two constants can be allocated the same constant pool
1395 /// entry.
1396 static bool CanShareConstantPoolEntry(const Constant *A, const Constant *B,
1397                                       const DataLayout &DL) {
1398   // Handle the trivial case quickly.
1399   if (A == B) return true;
1400 
1401   // If they have the same type but weren't the same constant, quickly
1402   // reject them.
1403   if (A->getType() == B->getType()) return false;
1404 
1405   // We can't handle structs or arrays.
1406   if (isa<StructType>(A->getType()) || isa<ArrayType>(A->getType()) ||
1407       isa<StructType>(B->getType()) || isa<ArrayType>(B->getType()))
1408     return false;
1409 
1410   // For now, only support constants with the same size.
1411   uint64_t StoreSize = DL.getTypeStoreSize(A->getType());
1412   if (StoreSize != DL.getTypeStoreSize(B->getType()) || StoreSize > 128)
1413     return false;
1414 
1415   Type *IntTy = IntegerType::get(A->getContext(), StoreSize*8);
1416 
1417   // Try constant folding a bitcast of both instructions to an integer.  If we
1418   // get two identical ConstantInt's, then we are good to share them.  We use
1419   // the constant folding APIs to do this so that we get the benefit of
1420   // DataLayout.
1421   if (isa<PointerType>(A->getType()))
1422     A = ConstantFoldCastOperand(Instruction::PtrToInt,
1423                                 const_cast<Constant *>(A), IntTy, DL);
1424   else if (A->getType() != IntTy)
1425     A = ConstantFoldCastOperand(Instruction::BitCast, const_cast<Constant *>(A),
1426                                 IntTy, DL);
1427   if (isa<PointerType>(B->getType()))
1428     B = ConstantFoldCastOperand(Instruction::PtrToInt,
1429                                 const_cast<Constant *>(B), IntTy, DL);
1430   else if (B->getType() != IntTy)
1431     B = ConstantFoldCastOperand(Instruction::BitCast, const_cast<Constant *>(B),
1432                                 IntTy, DL);
1433 
1434   return A == B;
1435 }
1436 
1437 /// Create a new entry in the constant pool or return an existing one.
1438 /// User must specify the log2 of the minimum required alignment for the object.
1439 unsigned MachineConstantPool::getConstantPoolIndex(const Constant *C,
1440                                                    Align Alignment) {
1441   if (Alignment > PoolAlignment) PoolAlignment = Alignment;
1442 
1443   // Check to see if we already have this constant.
1444   //
1445   // FIXME, this could be made much more efficient for large constant pools.
1446   for (unsigned i = 0, e = Constants.size(); i != e; ++i)
1447     if (!Constants[i].isMachineConstantPoolEntry() &&
1448         CanShareConstantPoolEntry(Constants[i].Val.ConstVal, C, DL)) {
1449       if (Constants[i].getAlign() < Alignment)
1450         Constants[i].Alignment = Alignment;
1451       return i;
1452     }
1453 
1454   Constants.push_back(MachineConstantPoolEntry(C, Alignment));
1455   return Constants.size()-1;
1456 }
1457 
1458 unsigned MachineConstantPool::getConstantPoolIndex(MachineConstantPoolValue *V,
1459                                                    Align Alignment) {
1460   if (Alignment > PoolAlignment) PoolAlignment = Alignment;
1461 
1462   // Check to see if we already have this constant.
1463   //
1464   // FIXME, this could be made much more efficient for large constant pools.
1465   int Idx = V->getExistingMachineCPValue(this, Alignment);
1466   if (Idx != -1) {
1467     MachineCPVsSharingEntries.insert(V);
1468     return (unsigned)Idx;
1469   }
1470 
1471   Constants.push_back(MachineConstantPoolEntry(V, Alignment));
1472   return Constants.size()-1;
1473 }
1474 
1475 void MachineConstantPool::print(raw_ostream &OS) const {
1476   if (Constants.empty()) return;
1477 
1478   OS << "Constant Pool:\n";
1479   for (unsigned i = 0, e = Constants.size(); i != e; ++i) {
1480     OS << "  cp#" << i << ": ";
1481     if (Constants[i].isMachineConstantPoolEntry())
1482       Constants[i].Val.MachineCPVal->print(OS);
1483     else
1484       Constants[i].Val.ConstVal->printAsOperand(OS, /*PrintType=*/false);
1485     OS << ", align=" << Constants[i].getAlign().value();
1486     OS << "\n";
1487   }
1488 }
1489 
1490 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
1491 LLVM_DUMP_METHOD void MachineConstantPool::dump() const { print(dbgs()); }
1492 #endif
1493