llvm/lib/CodeGen/MachineFunction.cpp

   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 (auto MA = F.getFnStackAlign())
 133     return MA->value();
 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