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 #include "LiveDebugValues/LiveDebugValues.h"
  80
  81 using namespace llvm;
  82
  83 #define DEBUG_TYPE "codegen"
  84
  85 static cl::opt<unsigned> AlignAllFunctions(
  86     "align-all-functions",
  87     cl::desc("Force the alignment of all functions in log2 format (e.g. 4 "
  88              "means align on 16B boundaries)."),
  89     cl::init(0), cl::Hidden);
  90
  91 static const char *getPropertyName(MachineFunctionProperties::Property Prop) {
  92   using P = MachineFunctionProperties::Property;
  93
  94   // clang-format off
  95   switch(Prop) {
  96   case P::FailedISel: return "FailedISel";
  97   case P::IsSSA: return "IsSSA";
  98   case P::Legalized: return "Legalized";
  99   case P::NoPHIs: return "NoPHIs";
 100   case P::NoVRegs: return "NoVRegs";
 101   case P::RegBankSelected: return "RegBankSelected";
 102   case P::Selected: return "Selected";
 103   case P::TracksLiveness: return "TracksLiveness";
 104   case P::TiedOpsRewritten: return "TiedOpsRewritten";
 105   case P::FailsVerification: return "FailsVerification";
 106   case P::TracksDebugUserValues: return "TracksDebugUserValues";
 107   }
 108   // clang-format on
 109   llvm_unreachable("Invalid machine function property");
 110 }
 111
 112 // Pin the vtable to this file.
 113 void MachineFunction::Delegate::anchor() {}
 114
 115 void MachineFunctionProperties::print(raw_ostream &OS) const {
 116   const char *Separator = "";
 117   for (BitVector::size_type I = 0; I < Properties.size(); ++I) {
 118     if (!Properties[I])
 119       continue;
 120     OS << Separator << getPropertyName(static_cast<Property>(I));
 121     Separator = ", ";
 122   }
 123 }
 124
 125 //===----------------------------------------------------------------------===//
 126 // MachineFunction implementation
 127 //===----------------------------------------------------------------------===//
 128
 129 // Out-of-line virtual method.
 130 MachineFunctionInfo::~MachineFunctionInfo() = default;
 131
 132 void ilist_alloc_traits<MachineBasicBlock>::deleteNode(MachineBasicBlock *MBB) {
 133   MBB->getParent()->deleteMachineBasicBlock(MBB);
 134 }
 135
 136 static inline unsigned getFnStackAlignment(const TargetSubtargetInfo *STI,
 137                                            const Function &F) {
 138   if (auto MA = F.getFnStackAlign())
 139     return MA->value();
 140   return STI->getFrameLowering()->getStackAlign().value();
 141 }
 142
 143 MachineFunction::MachineFunction(Function &F, const LLVMTargetMachine &Target,
 144                                  const TargetSubtargetInfo &STI,
 145                                  unsigned FunctionNum, MachineModuleInfo &mmi)
 146     : F(F), Target(Target), STI(&STI), Ctx(mmi.getContext()), MMI(mmi) {
 147   FunctionNumber = FunctionNum;
 148   init();
 149 }
 150
 151 void MachineFunction::handleInsertion(MachineInstr &MI) {
 152   if (TheDelegate)
 153     TheDelegate->MF_HandleInsertion(MI);
 154 }
 155
 156 void MachineFunction::handleRemoval(MachineInstr &MI) {
 157   if (TheDelegate)
 158     TheDelegate->MF_HandleRemoval(MI);
 159 }
 160
 161 void MachineFunction::init() {
 162   // Assume the function starts in SSA form with correct liveness.
 163   Properties.set(MachineFunctionProperties::Property::IsSSA);
 164   Properties.set(MachineFunctionProperties::Property::TracksLiveness);
 165   if (STI->getRegisterInfo())
 166     RegInfo = new (Allocator) MachineRegisterInfo(this);
 167   else
 168     RegInfo = nullptr;
 169
 170   MFInfo = nullptr;
 171   // We can realign the stack if the target supports it and the user hasn't
 172   // explicitly asked us not to.
 173   bool CanRealignSP = STI->getFrameLowering()->isStackRealignable() &&
 174                       !F.hasFnAttribute("no-realign-stack");
 175   FrameInfo = new (Allocator) MachineFrameInfo(
 176       getFnStackAlignment(STI, F), /*StackRealignable=*/CanRealignSP,
 177       /*ForcedRealign=*/CanRealignSP &&
 178           F.hasFnAttribute(Attribute::StackAlignment));
 179
 180   if (F.hasFnAttribute(Attribute::StackAlignment))
 181     FrameInfo->ensureMaxAlignment(*F.getFnStackAlign());
 182
 183   ConstantPool = new (Allocator) MachineConstantPool(getDataLayout());
 184   Alignment = STI->getTargetLowering()->getMinFunctionAlignment();
 185
 186   // FIXME: Shouldn't use pref alignment if explicit alignment is set on F.
 187   // FIXME: Use Function::hasOptSize().
 188   if (!F.hasFnAttribute(Attribute::OptimizeForSize))
 189     Alignment = std::max(Alignment,
 190                          STI->getTargetLowering()->getPrefFunctionAlignment());
 191
 192   if (AlignAllFunctions)
 193     Alignment = Align(1ULL << AlignAllFunctions);
 194
 195   JumpTableInfo = nullptr;
 196
 197   if (isFuncletEHPersonality(classifyEHPersonality(
 198           F.hasPersonalityFn() ? F.getPersonalityFn() : nullptr))) {
 199     WinEHInfo = new (Allocator) WinEHFuncInfo();
 200   }
 201
 202   if (isScopedEHPersonality(classifyEHPersonality(
 203           F.hasPersonalityFn() ? F.getPersonalityFn() : nullptr))) {
 204     WasmEHInfo = new (Allocator) WasmEHFuncInfo();
 205   }
 206
 207   assert(Target.isCompatibleDataLayout(getDataLayout()) &&
 208          "Can't create a MachineFunction using a Module with a "
 209          "Target-incompatible DataLayout attached\n");
 210
 211   PSVManager =
 212     std::make_unique<PseudoSourceValueManager>(*(getSubtarget().
 213                                                   getInstrInfo()));
 214 }
 215
 216 MachineFunction::~MachineFunction() {
 217   clear();
 218 }
 219
 220 void MachineFunction::clear() {
 221   Properties.reset();
 222   // Don't call destructors on MachineInstr and MachineOperand. All of their
 223   // memory comes from the BumpPtrAllocator which is about to be purged.
 224   //
 225   // Do call MachineBasicBlock destructors, it contains std::vectors.
 226   for (iterator I = begin(), E = end(); I != E; I = BasicBlocks.erase(I))
 227     I->Insts.clearAndLeakNodesUnsafely();
 228   MBBNumbering.clear();
 229
 230   InstructionRecycler.clear(Allocator);
 231   OperandRecycler.clear(Allocator);
 232   BasicBlockRecycler.clear(Allocator);
 233   CodeViewAnnotations.clear();
 234   VariableDbgInfos.clear();
 235   if (RegInfo) {
 236     RegInfo->~MachineRegisterInfo();
 237     Allocator.Deallocate(RegInfo);
 238   }
 239   if (MFInfo) {
 240     MFInfo->~MachineFunctionInfo();
 241     Allocator.Deallocate(MFInfo);
 242   }
 243
 244   FrameInfo->~MachineFrameInfo();
 245   Allocator.Deallocate(FrameInfo);
 246
 247   ConstantPool->~MachineConstantPool();
 248   Allocator.Deallocate(ConstantPool);
 249
 250   if (JumpTableInfo) {
 251     JumpTableInfo->~MachineJumpTableInfo();
 252     Allocator.Deallocate(JumpTableInfo);
 253   }
 254
 255   if (WinEHInfo) {
 256     WinEHInfo->~WinEHFuncInfo();
 257     Allocator.Deallocate(WinEHInfo);
 258   }
 259
 260   if (WasmEHInfo) {
 261     WasmEHInfo->~WasmEHFuncInfo();
 262     Allocator.Deallocate(WasmEHInfo);
 263   }
 264 }
 265
 266 const DataLayout &MachineFunction::getDataLayout() const {
 267   return F.getParent()->getDataLayout();
 268 }
 269
 270 /// Get the JumpTableInfo for this function.
 271 /// If it does not already exist, allocate one.
 272 MachineJumpTableInfo *MachineFunction::
 273 getOrCreateJumpTableInfo(unsigned EntryKind) {
 274   if (JumpTableInfo) return JumpTableInfo;
 275
 276   JumpTableInfo = new (Allocator)
 277     MachineJumpTableInfo((MachineJumpTableInfo::JTEntryKind)EntryKind);
 278   return JumpTableInfo;
 279 }
 280
 281 DenormalMode MachineFunction::getDenormalMode(const fltSemantics &FPType) const {
 282   return F.getDenormalMode(FPType);
 283 }
 284
 285 /// Should we be emitting segmented stack stuff for the function
 286 bool MachineFunction::shouldSplitStack() const {
 287   return getFunction().hasFnAttribute("split-stack");
 288 }
 289
 290 LLVM_NODISCARD unsigned
 291 MachineFunction::addFrameInst(const MCCFIInstruction &Inst) {
 292   FrameInstructions.push_back(Inst);
 293   return FrameInstructions.size() - 1;
 294 }
 295
 296 /// This discards all of the MachineBasicBlock numbers and recomputes them.
 297 /// This guarantees that the MBB numbers are sequential, dense, and match the
 298 /// ordering of the blocks within the function.  If a specific MachineBasicBlock
 299 /// is specified, only that block and those after it are renumbered.
 300 void MachineFunction::RenumberBlocks(MachineBasicBlock *MBB) {
 301   if (empty()) { MBBNumbering.clear(); return; }
 302   MachineFunction::iterator MBBI, E = end();
 303   if (MBB == nullptr)
 304     MBBI = begin();
 305   else
 306     MBBI = MBB->getIterator();
 307
 308   // Figure out the block number this should have.
 309   unsigned BlockNo = 0;
 310   if (MBBI != begin())
 311     BlockNo = std::prev(MBBI)->getNumber() + 1;
 312
 313   for (; MBBI != E; ++MBBI, ++BlockNo) {
 314     if (MBBI->getNumber() != (int)BlockNo) {
 315       // Remove use of the old number.
 316       if (MBBI->getNumber() != -1) {
 317         assert(MBBNumbering[MBBI->getNumber()] == &*MBBI &&
 318                "MBB number mismatch!");
 319         MBBNumbering[MBBI->getNumber()] = nullptr;
 320       }
 321
 322       // If BlockNo is already taken, set that block's number to -1.
 323       if (MBBNumbering[BlockNo])
 324         MBBNumbering[BlockNo]->setNumber(-1);
 325
 326       MBBNumbering[BlockNo] = &*MBBI;
 327       MBBI->setNumber(BlockNo);
 328     }
 329   }
 330
 331   // Okay, all the blocks are renumbered.  If we have compactified the block
 332   // numbering, shrink MBBNumbering now.
 333   assert(BlockNo <= MBBNumbering.size() && "Mismatch!");
 334   MBBNumbering.resize(BlockNo);
 335 }
 336
 337 /// This method iterates over the basic blocks and assigns their IsBeginSection
 338 /// and IsEndSection fields. This must be called after MBB layout is finalized
 339 /// and the SectionID's are assigned to MBBs.
 340 void MachineFunction::assignBeginEndSections() {
 341   front().setIsBeginSection();
 342   auto CurrentSectionID = front().getSectionID();
 343   for (auto MBBI = std::next(begin()), E = end(); MBBI != E; ++MBBI) {
 344     if (MBBI->getSectionID() == CurrentSectionID)
 345       continue;
 346     MBBI->setIsBeginSection();
 347     std::prev(MBBI)->setIsEndSection();
 348     CurrentSectionID = MBBI->getSectionID();
 349   }
 350   back().setIsEndSection();
 351 }
 352
 353 /// Allocate a new MachineInstr. Use this instead of `new MachineInstr'.
 354 MachineInstr *MachineFunction::CreateMachineInstr(const MCInstrDesc &MCID,
 355                                                   DebugLoc DL,
 356                                                   bool NoImplicit) {
 357   return new (InstructionRecycler.Allocate<MachineInstr>(Allocator))
 358       MachineInstr(*this, MCID, std::move(DL), NoImplicit);
 359 }
 360
 361 /// Create a new MachineInstr which is a copy of the 'Orig' instruction,
 362 /// identical in all ways except the instruction has no parent, prev, or next.
 363 MachineInstr *
 364 MachineFunction::CloneMachineInstr(const MachineInstr *Orig) {
 365   return new (InstructionRecycler.Allocate<MachineInstr>(Allocator))
 366              MachineInstr(*this, *Orig);
 367 }
 368
 369 MachineInstr &MachineFunction::cloneMachineInstrBundle(
 370     MachineBasicBlock &MBB, MachineBasicBlock::iterator InsertBefore,
 371     const MachineInstr &Orig) {
 372   MachineInstr *FirstClone = nullptr;
 373   MachineBasicBlock::const_instr_iterator I = Orig.getIterator();
 374   while (true) {
 375     MachineInstr *Cloned = CloneMachineInstr(&*I);
 376     MBB.insert(InsertBefore, Cloned);
 377     if (FirstClone == nullptr) {
 378       FirstClone = Cloned;
 379     } else {
 380       Cloned->bundleWithPred();
 381     }
 382
 383     if (!I->isBundledWithSucc())
 384       break;
 385     ++I;
 386   }
 387   // Copy over call site info to the cloned instruction if needed. If Orig is in
 388   // a bundle, copyCallSiteInfo takes care of finding the call instruction in
 389   // the bundle.
 390   if (Orig.shouldUpdateCallSiteInfo())
 391     copyCallSiteInfo(&Orig, FirstClone);
 392   return *FirstClone;
 393 }
 394
 395 /// Delete the given MachineInstr.
 396 ///
 397 /// This function also serves as the MachineInstr destructor - the real
 398 /// ~MachineInstr() destructor must be empty.
 399 void MachineFunction::deleteMachineInstr(MachineInstr *MI) {
 400   // Verify that a call site info is at valid state. This assertion should
 401   // be triggered during the implementation of support for the
 402   // call site info of a new architecture. If the assertion is triggered,
 403   // back trace will tell where to insert a call to updateCallSiteInfo().
 404   assert((!MI->isCandidateForCallSiteEntry() ||
 405           CallSitesInfo.find(MI) == CallSitesInfo.end()) &&
 406          "Call site info was not updated!");
 407   // Strip it for parts. The operand array and the MI object itself are
 408   // independently recyclable.
 409   if (MI->Operands)
 410     deallocateOperandArray(MI->CapOperands, MI->Operands);
 411   // Don't call ~MachineInstr() which must be trivial anyway because
 412   // ~MachineFunction drops whole lists of MachineInstrs wihout calling their
 413   // destructors.
 414   InstructionRecycler.Deallocate(Allocator, MI);
 415 }
 416
 417 /// Allocate a new MachineBasicBlock. Use this instead of
 418 /// `new MachineBasicBlock'.
 419 MachineBasicBlock *
 420 MachineFunction::CreateMachineBasicBlock(const BasicBlock *bb) {
 421   return new (BasicBlockRecycler.Allocate<MachineBasicBlock>(Allocator))
 422              MachineBasicBlock(*this, bb);
 423 }
 424
 425 /// Delete the given MachineBasicBlock.
 426 void MachineFunction::deleteMachineBasicBlock(MachineBasicBlock *MBB) {
 427   assert(MBB->getParent() == this && "MBB parent mismatch!");
 428   // Clean up any references to MBB in jump tables before deleting it.
 429   if (JumpTableInfo)
 430     JumpTableInfo->RemoveMBBFromJumpTables(MBB);
 431   MBB->~MachineBasicBlock();
 432   BasicBlockRecycler.Deallocate(Allocator, MBB);
 433 }
 434
 435 MachineMemOperand *MachineFunction::getMachineMemOperand(
 436     MachinePointerInfo PtrInfo, MachineMemOperand::Flags f, uint64_t s,
 437     Align base_alignment, const AAMDNodes &AAInfo, const MDNode *Ranges,
 438     SyncScope::ID SSID, AtomicOrdering Ordering,
 439     AtomicOrdering FailureOrdering) {
 440   return new (Allocator)
 441       MachineMemOperand(PtrInfo, f, s, base_alignment, AAInfo, Ranges,
 442                         SSID, Ordering, FailureOrdering);
 443 }
 444
 445 MachineMemOperand *MachineFunction::getMachineMemOperand(
 446     MachinePointerInfo PtrInfo, MachineMemOperand::Flags f, LLT MemTy,
 447     Align base_alignment, const AAMDNodes &AAInfo, const MDNode *Ranges,
 448     SyncScope::ID SSID, AtomicOrdering Ordering,
 449     AtomicOrdering FailureOrdering) {
 450   return new (Allocator)
 451       MachineMemOperand(PtrInfo, f, MemTy, base_alignment, AAInfo, Ranges, SSID,
 452                         Ordering, FailureOrdering);
 453 }
 454
 455 MachineMemOperand *MachineFunction::getMachineMemOperand(
 456     const MachineMemOperand *MMO, const MachinePointerInfo &PtrInfo, uint64_t Size) {
 457   return new (Allocator)
 458       MachineMemOperand(PtrInfo, MMO->getFlags(), Size, MMO->getBaseAlign(),
 459                         AAMDNodes(), nullptr, MMO->getSyncScopeID(),
 460                         MMO->getSuccessOrdering(), MMO->getFailureOrdering());
 461 }
 462
 463 MachineMemOperand *MachineFunction::getMachineMemOperand(
 464     const MachineMemOperand *MMO, const MachinePointerInfo &PtrInfo, LLT Ty) {
 465   return new (Allocator)
 466       MachineMemOperand(PtrInfo, MMO->getFlags(), Ty, MMO->getBaseAlign(),
 467                         AAMDNodes(), nullptr, MMO->getSyncScopeID(),
 468                         MMO->getSuccessOrdering(), MMO->getFailureOrdering());
 469 }
 470
 471 MachineMemOperand *
 472 MachineFunction::getMachineMemOperand(const MachineMemOperand *MMO,
 473                                       int64_t Offset, LLT Ty) {
 474   const MachinePointerInfo &PtrInfo = MMO->getPointerInfo();
 475
 476   // If there is no pointer value, the offset isn't tracked so we need to adjust
 477   // the base alignment.
 478   Align Alignment = PtrInfo.V.isNull()
 479                         ? commonAlignment(MMO->getBaseAlign(), Offset)
 480                         : MMO->getBaseAlign();
 481
 482   // Do not preserve ranges, since we don't necessarily know what the high bits
 483   // are anymore.
 484   return new (Allocator) MachineMemOperand(
 485       PtrInfo.getWithOffset(Offset), MMO->getFlags(), Ty, Alignment,
 486       MMO->getAAInfo(), nullptr, MMO->getSyncScopeID(),
 487       MMO->getSuccessOrdering(), MMO->getFailureOrdering());
 488 }
 489
 490 MachineMemOperand *
 491 MachineFunction::getMachineMemOperand(const MachineMemOperand *MMO,
 492                                       const AAMDNodes &AAInfo) {
 493   MachinePointerInfo MPI = MMO->getValue() ?
 494              MachinePointerInfo(MMO->getValue(), MMO->getOffset()) :
 495              MachinePointerInfo(MMO->getPseudoValue(), MMO->getOffset());
 496
 497   return new (Allocator) MachineMemOperand(
 498       MPI, MMO->getFlags(), MMO->getSize(), MMO->getBaseAlign(), AAInfo,
 499       MMO->getRanges(), MMO->getSyncScopeID(), MMO->getSuccessOrdering(),
 500       MMO->getFailureOrdering());
 501 }
 502
 503 MachineMemOperand *
 504 MachineFunction::getMachineMemOperand(const MachineMemOperand *MMO,
 505                                       MachineMemOperand::Flags Flags) {
 506   return new (Allocator) MachineMemOperand(
 507       MMO->getPointerInfo(), Flags, MMO->getSize(), MMO->getBaseAlign(),
 508       MMO->getAAInfo(), MMO->getRanges(), MMO->getSyncScopeID(),
 509       MMO->getSuccessOrdering(), MMO->getFailureOrdering());
 510 }
 511
 512 MachineInstr::ExtraInfo *MachineFunction::createMIExtraInfo(
 513     ArrayRef<MachineMemOperand *> MMOs, MCSymbol *PreInstrSymbol,
 514     MCSymbol *PostInstrSymbol, MDNode *HeapAllocMarker) {
 515   return MachineInstr::ExtraInfo::create(Allocator, MMOs, PreInstrSymbol,
 516                                          PostInstrSymbol, HeapAllocMarker);
 517 }
 518
 519 const char *MachineFunction::createExternalSymbolName(StringRef Name) {
 520   char *Dest = Allocator.Allocate<char>(Name.size() + 1);
 521   llvm::copy(Name, Dest);
 522   Dest[Name.size()] = 0;
 523   return Dest;
 524 }
 525
 526 uint32_t *MachineFunction::allocateRegMask() {
 527   unsigned NumRegs = getSubtarget().getRegisterInfo()->getNumRegs();
 528   unsigned Size = MachineOperand::getRegMaskSize(NumRegs);
 529   uint32_t *Mask = Allocator.Allocate<uint32_t>(Size);
 530   memset(Mask, 0, Size * sizeof(Mask[0]));
 531   return Mask;
 532 }
 533
 534 ArrayRef<int> MachineFunction::allocateShuffleMask(ArrayRef<int> Mask) {
 535   int* AllocMask = Allocator.Allocate<int>(Mask.size());
 536   copy(Mask, AllocMask);
 537   return {AllocMask, Mask.size()};
 538 }
 539
 540 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
 541 LLVM_DUMP_METHOD void MachineFunction::dump() const {
 542   print(dbgs());
 543 }
 544 #endif
 545
 546 StringRef MachineFunction::getName() const {
 547   return getFunction().getName();
 548 }
 549
 550 void MachineFunction::print(raw_ostream &OS, const SlotIndexes *Indexes) const {
 551   OS << "# Machine code for function " << getName() << ": ";
 552   getProperties().print(OS);
 553   OS << '\n';
 554
 555   // Print Frame Information
 556   FrameInfo->print(*this, OS);
 557
 558   // Print JumpTable Information
 559   if (JumpTableInfo)
 560     JumpTableInfo->print(OS);
 561
 562   // Print Constant Pool
 563   ConstantPool->print(OS);
 564
 565   const TargetRegisterInfo *TRI = getSubtarget().getRegisterInfo();
 566
 567   if (RegInfo && !RegInfo->livein_empty()) {
 568     OS << "Function Live Ins: ";
 569     for (MachineRegisterInfo::livein_iterator
 570          I = RegInfo->livein_begin(), E = RegInfo->livein_end(); I != E; ++I) {
 571       OS << printReg(I->first, TRI);
 572       if (I->second)
 573         OS << " in " << printReg(I->second, TRI);
 574       if (std::next(I) != E)
 575         OS << ", ";
 576     }
 577     OS << '\n';
 578   }
 579
 580   ModuleSlotTracker MST(getFunction().getParent());
 581   MST.incorporateFunction(getFunction());
 582   for (const auto &BB : *this) {
 583     OS << '\n';
 584     // If we print the whole function, print it at its most verbose level.
 585     BB.print(OS, MST, Indexes, /*IsStandalone=*/true);
 586   }
 587
 588   OS << "\n# End machine code for function " << getName() << ".\n\n";
 589 }
 590
 591 /// True if this function needs frame moves for debug or exceptions.
 592 bool MachineFunction::needsFrameMoves() const {
 593   return getMMI().hasDebugInfo() ||
 594          getTarget().Options.ForceDwarfFrameSection ||
 595          F.needsUnwindTableEntry();
 596 }
 597
 598 namespace llvm {
 599
 600   template<>
 601   struct DOTGraphTraits<const MachineFunction*> : public DefaultDOTGraphTraits {
 602     DOTGraphTraits(bool isSimple = false) : DefaultDOTGraphTraits(isSimple) {}
 603
 604     static std::string getGraphName(const MachineFunction *F) {
 605       return ("CFG for '" + F->getName() + "' function").str();
 606     }
 607
 608     std::string getNodeLabel(const MachineBasicBlock *Node,
 609                              const MachineFunction *Graph) {
 610       std::string OutStr;
 611       {
 612         raw_string_ostream OSS(OutStr);
 613
 614         if (isSimple()) {
 615           OSS << printMBBReference(*Node);
 616           if (const BasicBlock *BB = Node->getBasicBlock())
 617             OSS << ": " << BB->getName();
 618         } else
 619           Node->print(OSS);
 620       }
 621
 622       if (OutStr[0] == '\n') OutStr.erase(OutStr.begin());
 623
 624       // Process string output to make it nicer...
 625       for (unsigned i = 0; i != OutStr.length(); ++i)
 626         if (OutStr[i] == '\n') {                            // Left justify
 627           OutStr[i] = '\\';
 628           OutStr.insert(OutStr.begin()+i+1, 'l');
 629         }
 630       return OutStr;
 631     }
 632   };
 633
 634 } // end namespace llvm
 635
 636 void MachineFunction::viewCFG() const
 637 {
 638 #ifndef NDEBUG
 639   ViewGraph(this, "mf" + getName());
 640 #else
 641   errs() << "MachineFunction::viewCFG is only available in debug builds on "
 642          << "systems with Graphviz or gv!\n";
 643 #endif // NDEBUG
 644 }
 645
 646 void MachineFunction::viewCFGOnly() const
 647 {
 648 #ifndef NDEBUG
 649   ViewGraph(this, "mf" + getName(), true);
 650 #else
 651   errs() << "MachineFunction::viewCFGOnly is only available in debug builds on "
 652          << "systems with Graphviz or gv!\n";
 653 #endif // NDEBUG
 654 }
 655
 656 /// Add the specified physical register as a live-in value and
 657 /// create a corresponding virtual register for it.
 658 Register MachineFunction::addLiveIn(MCRegister PReg,
 659                                     const TargetRegisterClass *RC) {
 660   MachineRegisterInfo &MRI = getRegInfo();
 661   Register VReg = MRI.getLiveInVirtReg(PReg);
 662   if (VReg) {
 663     const TargetRegisterClass *VRegRC = MRI.getRegClass(VReg);
 664     (void)VRegRC;
 665     // A physical register can be added several times.
 666     // Between two calls, the register class of the related virtual register
 667     // may have been constrained to match some operation constraints.
 668     // In that case, check that the current register class includes the
 669     // physical register and is a sub class of the specified RC.
 670     assert((VRegRC == RC || (VRegRC->contains(PReg) &&
 671                              RC->hasSubClassEq(VRegRC))) &&
 672             "Register class mismatch!");
 673     return VReg;
 674   }
 675   VReg = MRI.createVirtualRegister(RC);
 676   MRI.addLiveIn(PReg, VReg);
 677   return VReg;
 678 }
 679
 680 /// Return the MCSymbol for the specified non-empty jump table.
 681 /// If isLinkerPrivate is specified, an 'l' label is returned, otherwise a
 682 /// normal 'L' label is returned.
 683 MCSymbol *MachineFunction::getJTISymbol(unsigned JTI, MCContext &Ctx,
 684                                         bool isLinkerPrivate) const {
 685   const DataLayout &DL = getDataLayout();
 686   assert(JumpTableInfo && "No jump tables");
 687   assert(JTI < JumpTableInfo->getJumpTables().size() && "Invalid JTI!");
 688
 689   StringRef Prefix = isLinkerPrivate ? DL.getLinkerPrivateGlobalPrefix()
 690                                      : DL.getPrivateGlobalPrefix();
 691   SmallString<60> Name;
 692   raw_svector_ostream(Name)
 693     << Prefix << "JTI" << getFunctionNumber() << '_' << JTI;
 694   return Ctx.getOrCreateSymbol(Name);
 695 }
 696
 697 /// Return a function-local symbol to represent the PIC base.
 698 MCSymbol *MachineFunction::getPICBaseSymbol() const {
 699   const DataLayout &DL = getDataLayout();
 700   return Ctx.getOrCreateSymbol(Twine(DL.getPrivateGlobalPrefix()) +
 701                                Twine(getFunctionNumber()) + "$pb");
 702 }
 703
 704 /// \name Exception Handling
 705 /// \{
 706
 707 LandingPadInfo &
 708 MachineFunction::getOrCreateLandingPadInfo(MachineBasicBlock *LandingPad) {
 709   unsigned N = LandingPads.size();
 710   for (unsigned i = 0; i < N; ++i) {
 711     LandingPadInfo &LP = LandingPads[i];
 712     if (LP.LandingPadBlock == LandingPad)
 713       return LP;
 714   }
 715
 716   LandingPads.push_back(LandingPadInfo(LandingPad));
 717   return LandingPads[N];
 718 }
 719
 720 void MachineFunction::addInvoke(MachineBasicBlock *LandingPad,
 721                                 MCSymbol *BeginLabel, MCSymbol *EndLabel) {
 722   LandingPadInfo &LP = getOrCreateLandingPadInfo(LandingPad);
 723   LP.BeginLabels.push_back(BeginLabel);
 724   LP.EndLabels.push_back(EndLabel);
 725 }
 726
 727 MCSymbol *MachineFunction::addLandingPad(MachineBasicBlock *LandingPad) {
 728   MCSymbol *LandingPadLabel = Ctx.createTempSymbol();
 729   LandingPadInfo &LP = getOrCreateLandingPadInfo(LandingPad);
 730   LP.LandingPadLabel = LandingPadLabel;
 731
 732   const Instruction *FirstI = LandingPad->getBasicBlock()->getFirstNonPHI();
 733   if (const auto *LPI = dyn_cast<LandingPadInst>(FirstI)) {
 734     if (const auto *PF =
 735             dyn_cast<Function>(F.getPersonalityFn()->stripPointerCasts()))
 736       getMMI().addPersonality(PF);
 737
 738     if (LPI->isCleanup())
 739       addCleanup(LandingPad);
 740
 741     // FIXME: New EH - Add the clauses in reverse order. This isn't 100%
 742     //        correct, but we need to do it this way because of how the DWARF EH
 743     //        emitter processes the clauses.
 744     for (unsigned I = LPI->getNumClauses(); I != 0; --I) {
 745       Value *Val = LPI->getClause(I - 1);
 746       if (LPI->isCatch(I - 1)) {
 747         addCatchTypeInfo(LandingPad,
 748                          dyn_cast<GlobalValue>(Val->stripPointerCasts()));
 749       } else {
 750         // Add filters in a list.
 751         auto *CVal = cast<Constant>(Val);
 752         SmallVector<const GlobalValue *, 4> FilterList;
 753         for (const Use &U : CVal->operands())
 754           FilterList.push_back(cast<GlobalValue>(U->stripPointerCasts()));
 755
 756         addFilterTypeInfo(LandingPad, FilterList);
 757       }
 758     }
 759
 760   } else if (const auto *CPI = dyn_cast<CatchPadInst>(FirstI)) {
 761     for (unsigned I = CPI->getNumArgOperands(); I != 0; --I) {
 762       Value *TypeInfo = CPI->getArgOperand(I - 1)->stripPointerCasts();
 763       addCatchTypeInfo(LandingPad, dyn_cast<GlobalValue>(TypeInfo));
 764     }
 765
 766   } else {
 767     assert(isa<CleanupPadInst>(FirstI) && "Invalid landingpad!");
 768   }
 769
 770   return LandingPadLabel;
 771 }
 772
 773 void MachineFunction::addCatchTypeInfo(MachineBasicBlock *LandingPad,
 774                                        ArrayRef<const GlobalValue *> TyInfo) {
 775   LandingPadInfo &LP = getOrCreateLandingPadInfo(LandingPad);
 776   for (const GlobalValue *GV : llvm::reverse(TyInfo))
 777     LP.TypeIds.push_back(getTypeIDFor(GV));
 778 }
 779
 780 void MachineFunction::addFilterTypeInfo(MachineBasicBlock *LandingPad,
 781                                         ArrayRef<const GlobalValue *> TyInfo) {
 782   LandingPadInfo &LP = getOrCreateLandingPadInfo(LandingPad);
 783   std::vector<unsigned> IdsInFilter(TyInfo.size());
 784   for (unsigned I = 0, E = TyInfo.size(); I != E; ++I)
 785     IdsInFilter[I] = getTypeIDFor(TyInfo[I]);
 786   LP.TypeIds.push_back(getFilterIDFor(IdsInFilter));
 787 }
 788
 789 void MachineFunction::tidyLandingPads(DenseMap<MCSymbol *, uintptr_t> *LPMap,
 790                                       bool TidyIfNoBeginLabels) {
 791   for (unsigned i = 0; i != LandingPads.size(); ) {
 792     LandingPadInfo &LandingPad = LandingPads[i];
 793     if (LandingPad.LandingPadLabel &&
 794         !LandingPad.LandingPadLabel->isDefined() &&
 795         (!LPMap || (*LPMap)[LandingPad.LandingPadLabel] == 0))
 796       LandingPad.LandingPadLabel = nullptr;
 797
 798     // Special case: we *should* emit LPs with null LP MBB. This indicates
 799     // "nounwind" case.
 800     if (!LandingPad.LandingPadLabel && LandingPad.LandingPadBlock) {
 801       LandingPads.erase(LandingPads.begin() + i);
 802       continue;
 803     }
 804
 805     if (TidyIfNoBeginLabels) {
 806       for (unsigned j = 0, e = LandingPads[i].BeginLabels.size(); j != e; ++j) {
 807         MCSymbol *BeginLabel = LandingPad.BeginLabels[j];
 808         MCSymbol *EndLabel = LandingPad.EndLabels[j];
 809         if ((BeginLabel->isDefined() || (LPMap && (*LPMap)[BeginLabel] != 0)) &&
 810             (EndLabel->isDefined() || (LPMap && (*LPMap)[EndLabel] != 0)))
 811           continue;
 812
 813         LandingPad.BeginLabels.erase(LandingPad.BeginLabels.begin() + j);
 814         LandingPad.EndLabels.erase(LandingPad.EndLabels.begin() + j);
 815         --j;
 816         --e;
 817       }
 818
 819       // Remove landing pads with no try-ranges.
 820       if (LandingPads[i].BeginLabels.empty()) {
 821         LandingPads.erase(LandingPads.begin() + i);
 822         continue;
 823       }
 824     }
 825
 826     // If there is no landing pad, ensure that the list of typeids is empty.
 827     // If the only typeid is a cleanup, this is the same as having no typeids.
 828     if (!LandingPad.LandingPadBlock ||
 829         (LandingPad.TypeIds.size() == 1 && !LandingPad.TypeIds[0]))
 830       LandingPad.TypeIds.clear();
 831     ++i;
 832   }
 833 }
 834
 835 void MachineFunction::addCleanup(MachineBasicBlock *LandingPad) {
 836   LandingPadInfo &LP = getOrCreateLandingPadInfo(LandingPad);
 837   LP.TypeIds.push_back(0);
 838 }
 839
 840 void MachineFunction::addSEHCatchHandler(MachineBasicBlock *LandingPad,
 841                                          const Function *Filter,
 842                                          const BlockAddress *RecoverBA) {
 843   LandingPadInfo &LP = getOrCreateLandingPadInfo(LandingPad);
 844   SEHHandler Handler;
 845   Handler.FilterOrFinally = Filter;
 846   Handler.RecoverBA = RecoverBA;
 847   LP.SEHHandlers.push_back(Handler);
 848 }
 849
 850 void MachineFunction::addSEHCleanupHandler(MachineBasicBlock *LandingPad,
 851                                            const Function *Cleanup) {
 852   LandingPadInfo &LP = getOrCreateLandingPadInfo(LandingPad);
 853   SEHHandler Handler;
 854   Handler.FilterOrFinally = Cleanup;
 855   Handler.RecoverBA = nullptr;
 856   LP.SEHHandlers.push_back(Handler);
 857 }
 858
 859 void MachineFunction::setCallSiteLandingPad(MCSymbol *Sym,
 860                                             ArrayRef<unsigned> Sites) {
 861   LPadToCallSiteMap[Sym].append(Sites.begin(), Sites.end());
 862 }
 863
 864 unsigned MachineFunction::getTypeIDFor(const GlobalValue *TI) {
 865   for (unsigned i = 0, N = TypeInfos.size(); i != N; ++i)
 866     if (TypeInfos[i] == TI) return i + 1;
 867
 868   TypeInfos.push_back(TI);
 869   return TypeInfos.size();
 870 }
 871
 872 int MachineFunction::getFilterIDFor(std::vector<unsigned> &TyIds) {
 873   // If the new filter coincides with the tail of an existing filter, then
 874   // re-use the existing filter.  Folding filters more than this requires
 875   // re-ordering filters and/or their elements - probably not worth it.
 876   for (unsigned i : FilterEnds) {
 877     unsigned j = TyIds.size();
 878
 879     while (i && j)
 880       if (FilterIds[--i] != TyIds[--j])
 881         goto try_next;
 882
 883     if (!j)
 884       // The new filter coincides with range [i, end) of the existing filter.
 885       return -(1 + i);
 886
 887 try_next:;
 888   }
 889
 890   // Add the new filter.
 891   int FilterID = -(1 + FilterIds.size());
 892   FilterIds.reserve(FilterIds.size() + TyIds.size() + 1);
 893   llvm::append_range(FilterIds, TyIds);
 894   FilterEnds.push_back(FilterIds.size());
 895   FilterIds.push_back(0); // terminator
 896   return FilterID;
 897 }
 898
 899 MachineFunction::CallSiteInfoMap::iterator
 900 MachineFunction::getCallSiteInfo(const MachineInstr *MI) {
 901   assert(MI->isCandidateForCallSiteEntry() &&
 902          "Call site info refers only to call (MI) candidates");
 903
 904   if (!Target.Options.EmitCallSiteInfo)
 905     return CallSitesInfo.end();
 906   return CallSitesInfo.find(MI);
 907 }
 908
 909 /// Return the call machine instruction or find a call within bundle.
 910 static const MachineInstr *getCallInstr(const MachineInstr *MI) {
 911   if (!MI->isBundle())
 912     return MI;
 913
 914   for (auto &BMI : make_range(getBundleStart(MI->getIterator()),
 915                               getBundleEnd(MI->getIterator())))
 916     if (BMI.isCandidateForCallSiteEntry())
 917       return &BMI;
 918
 919   llvm_unreachable("Unexpected bundle without a call site candidate");
 920 }
 921
 922 void MachineFunction::eraseCallSiteInfo(const MachineInstr *MI) {
 923   assert(MI->shouldUpdateCallSiteInfo() &&
 924          "Call site info refers only to call (MI) candidates or "
 925          "candidates inside bundles");
 926
 927   const MachineInstr *CallMI = getCallInstr(MI);
 928   CallSiteInfoMap::iterator CSIt = getCallSiteInfo(CallMI);
 929   if (CSIt == CallSitesInfo.end())
 930     return;
 931   CallSitesInfo.erase(CSIt);
 932 }
 933
 934 void MachineFunction::copyCallSiteInfo(const MachineInstr *Old,
 935                                        const MachineInstr *New) {
 936   assert(Old->shouldUpdateCallSiteInfo() &&
 937          "Call site info refers only to call (MI) candidates or "
 938          "candidates inside bundles");
 939
 940   if (!New->isCandidateForCallSiteEntry())
 941     return eraseCallSiteInfo(Old);
 942
 943   const MachineInstr *OldCallMI = getCallInstr(Old);
 944   CallSiteInfoMap::iterator CSIt = getCallSiteInfo(OldCallMI);
 945   if (CSIt == CallSitesInfo.end())
 946     return;
 947
 948   CallSiteInfo CSInfo = CSIt->second;
 949   CallSitesInfo[New] = CSInfo;
 950 }
 951
 952 void MachineFunction::moveCallSiteInfo(const MachineInstr *Old,
 953                                        const MachineInstr *New) {
 954   assert(Old->shouldUpdateCallSiteInfo() &&
 955          "Call site info refers only to call (MI) candidates or "
 956          "candidates inside bundles");
 957
 958   if (!New->isCandidateForCallSiteEntry())
 959     return eraseCallSiteInfo(Old);
 960
 961   const MachineInstr *OldCallMI = getCallInstr(Old);
 962   CallSiteInfoMap::iterator CSIt = getCallSiteInfo(OldCallMI);
 963   if (CSIt == CallSitesInfo.end())
 964     return;
 965
 966   CallSiteInfo CSInfo = std::move(CSIt->second);
 967   CallSitesInfo.erase(CSIt);
 968   CallSitesInfo[New] = CSInfo;
 969 }
 970
 971 void MachineFunction::setDebugInstrNumberingCount(unsigned Num) {
 972   DebugInstrNumberingCount = Num;
 973 }
 974
 975 void MachineFunction::makeDebugValueSubstitution(DebugInstrOperandPair A,
 976                                                  DebugInstrOperandPair B,
 977                                                  unsigned Subreg) {
 978   // Catch any accidental self-loops.
 979   assert(A.first != B.first);
 980   // Don't allow any substitutions _from_ the memory operand number.
 981   assert(A.second != DebugOperandMemNumber);
 982
 983   DebugValueSubstitutions.push_back({A, B, Subreg});
 984 }
 985
 986 void MachineFunction::substituteDebugValuesForInst(const MachineInstr &Old,
 987                                                    MachineInstr &New,
 988                                                    unsigned MaxOperand) {
 989   // If the Old instruction wasn't tracked at all, there is no work to do.
 990   unsigned OldInstrNum = Old.peekDebugInstrNum();
 991   if (!OldInstrNum)
 992     return;
 993
 994   // Iterate over all operands looking for defs to create substitutions for.
 995   // Avoid creating new instr numbers unless we create a new substitution.
 996   // While this has no functional effect, it risks confusing someone reading
 997   // MIR output.
 998   // Examine all the operands, or the first N specified by the caller.
 999   MaxOperand = std::min(MaxOperand, Old.getNumOperands());
1000   for (unsigned int I = 0; I < MaxOperand; ++I) {
1001     const auto &OldMO = Old.getOperand(I);
1002     auto &NewMO = New.getOperand(I);
1003     (void)NewMO;
1004
1005     if (!OldMO.isReg() || !OldMO.isDef())
1006       continue;
1007     assert(NewMO.isDef());
1008
1009     unsigned NewInstrNum = New.getDebugInstrNum();
1010     makeDebugValueSubstitution(std::make_pair(OldInstrNum, I),
1011                                std::make_pair(NewInstrNum, I));
1012   }
1013 }
1014
1015 auto MachineFunction::salvageCopySSA(MachineInstr &MI)
1016     -> DebugInstrOperandPair {
1017   MachineRegisterInfo &MRI = getRegInfo();
1018   const TargetRegisterInfo &TRI = *MRI.getTargetRegisterInfo();
1019   const TargetInstrInfo &TII = *getSubtarget().getInstrInfo();
1020
1021   // Chase the value read by a copy-like instruction back to the instruction
1022   // that ultimately _defines_ that value. This may pass:
1023   //  * Through multiple intermediate copies, including subregister moves /
1024   //    copies,
1025   //  * Copies from physical registers that must then be traced back to the
1026   //    defining instruction,
1027   //  * Or, physical registers may be live-in to (only) the entry block, which
1028   //    requires a DBG_PHI to be created.
1029   // We can pursue this problem in that order: trace back through copies,
1030   // optionally through a physical register, to a defining instruction. We
1031   // should never move from physreg to vreg. As we're still in SSA form, no need
1032   // to worry about partial definitions of registers.
1033
1034   // Helper lambda to interpret a copy-like instruction. Takes instruction,
1035   // returns the register read and any subregister identifying which part is
1036   // read.
1037   auto GetRegAndSubreg =
1038       [&](const MachineInstr &Cpy) -> std::pair<Register, unsigned> {
1039     Register NewReg, OldReg;
1040     unsigned SubReg;
1041     if (Cpy.isCopy()) {
1042       OldReg = Cpy.getOperand(0).getReg();
1043       NewReg = Cpy.getOperand(1).getReg();
1044       SubReg = Cpy.getOperand(1).getSubReg();
1045     } else if (Cpy.isSubregToReg()) {
1046       OldReg = Cpy.getOperand(0).getReg();
1047       NewReg = Cpy.getOperand(2).getReg();
1048       SubReg = Cpy.getOperand(3).getImm();
1049     } else {
1050       auto CopyDetails = *TII.isCopyInstr(Cpy);
1051       const MachineOperand &Src = *CopyDetails.Source;
1052       const MachineOperand &Dest = *CopyDetails.Destination;
1053       OldReg = Dest.getReg();
1054       NewReg = Src.getReg();
1055       SubReg = Src.getSubReg();
1056     }
1057
1058     return {NewReg, SubReg};
1059   };
1060
1061   // First seek either the defining instruction, or a copy from a physreg.
1062   // During search, the current state is the current copy instruction, and which
1063   // register we've read. Accumulate qualifying subregisters into SubregsSeen;
1064   // deal with those later.
1065   auto State = GetRegAndSubreg(MI);
1066   auto CurInst = MI.getIterator();
1067   SmallVector<unsigned, 4> SubregsSeen;
1068   while (true) {
1069     // If we've found a copy from a physreg, first portion of search is over.
1070     if (!State.first.isVirtual())
1071       break;
1072
1073     // Record any subregister qualifier.
1074     if (State.second)
1075       SubregsSeen.push_back(State.second);
1076
1077     assert(MRI.hasOneDef(State.first));
1078     MachineInstr &Inst = *MRI.def_begin(State.first)->getParent();
1079     CurInst = Inst.getIterator();
1080
1081     // Any non-copy instruction is the defining instruction we're seeking.
1082     if (!Inst.isCopyLike() && !TII.isCopyInstr(Inst))
1083       break;
1084     State = GetRegAndSubreg(Inst);
1085   };
1086
1087   // Helper lambda to apply additional subregister substitutions to a known
1088   // instruction/operand pair. Adds new (fake) substitutions so that we can
1089   // record the subregister. FIXME: this isn't very space efficient if multiple
1090   // values are tracked back through the same copies; cache something later.
1091   auto ApplySubregisters =
1092       [&](DebugInstrOperandPair P) -> DebugInstrOperandPair {
1093     for (unsigned Subreg : reverse(SubregsSeen)) {
1094       // Fetch a new instruction number, not attached to an actual instruction.
1095       unsigned NewInstrNumber = getNewDebugInstrNum();
1096       // Add a substitution from the "new" number to the known one, with a
1097       // qualifying subreg.
1098       makeDebugValueSubstitution({NewInstrNumber, 0}, P, Subreg);
1099       // Return the new number; to find the underlying value, consumers need to
1100       // deal with the qualifying subreg.
1101       P = {NewInstrNumber, 0};
1102     }
1103     return P;
1104   };
1105
1106   // If we managed to find the defining instruction after COPYs, return an
1107   // instruction / operand pair after adding subregister qualifiers.
1108   if (State.first.isVirtual()) {
1109     // Virtual register def -- we can just look up where this happens.
1110     MachineInstr *Inst = MRI.def_begin(State.first)->getParent();
1111     for (auto &MO : Inst->operands()) {
1112       if (!MO.isReg() || !MO.isDef() || MO.getReg() != State.first)
1113         continue;
1114       return ApplySubregisters(
1115           {Inst->getDebugInstrNum(), Inst->getOperandNo(&MO)});
1116     }
1117
1118     llvm_unreachable("Vreg def with no corresponding operand?");
1119   }
1120
1121   // Our search ended in a copy from a physreg: walk back up the function
1122   // looking for whatever defines the physreg.
1123   assert(CurInst->isCopyLike() || TII.isCopyInstr(*CurInst));
1124   State = GetRegAndSubreg(*CurInst);
1125   Register RegToSeek = State.first;
1126
1127   auto RMII = CurInst->getReverseIterator();
1128   auto PrevInstrs = make_range(RMII, CurInst->getParent()->instr_rend());
1129   for (auto &ToExamine : PrevInstrs) {
1130     for (auto &MO : ToExamine.operands()) {
1131       // Test for operand that defines something aliasing RegToSeek.
1132       if (!MO.isReg() || !MO.isDef() ||
1133           !TRI.regsOverlap(RegToSeek, MO.getReg()))
1134         continue;
1135
1136       return ApplySubregisters(
1137           {ToExamine.getDebugInstrNum(), ToExamine.getOperandNo(&MO)});
1138     }
1139   }
1140
1141   MachineBasicBlock &InsertBB = *CurInst->getParent();
1142
1143   // We reached the start of the block before finding a defining instruction.
1144   // It could be from a constant register, otherwise it must be an argument.
1145   if (TRI.isConstantPhysReg(State.first)) {
1146     // We can produce a DBG_PHI that identifies the constant physreg. Doesn't
1147     // matter where we put it, as it's constant valued.
1148     assert(CurInst->isCopy());
1149   } else if (State.first == TRI.getFrameRegister(*this)) {
1150     // LLVM IR is allowed to read the framepointer by calling a
1151     // llvm.frameaddress.* intrinsic. We can support this by emitting a
1152     // DBG_PHI $fp. This isn't ideal, because it extends the behaviours /
1153     // position that DBG_PHIs appear at, limiting what can be done later.
1154     // TODO: see if there's a better way of expressing these variable
1155     // locations.
1156     ;
1157   } else {
1158     // Assert that this is the entry block, or an EH pad. If it isn't, then
1159     // there is some code construct we don't recognise that deals with physregs
1160     // across blocks.
1161     assert(!State.first.isVirtual());
1162     assert(&*InsertBB.getParent()->begin() == &InsertBB || InsertBB.isEHPad());
1163   }
1164
1165   // Create DBG_PHI for specified physreg.
1166   auto Builder = BuildMI(InsertBB, InsertBB.getFirstNonPHI(), DebugLoc(),
1167                          TII.get(TargetOpcode::DBG_PHI));
1168   Builder.addReg(State.first);
1169   unsigned NewNum = getNewDebugInstrNum();
1170   Builder.addImm(NewNum);
1171   return ApplySubregisters({NewNum, 0u});
1172 }
1173
1174 void MachineFunction::finalizeDebugInstrRefs() {
1175   auto *TII = getSubtarget().getInstrInfo();
1176
1177   auto MakeUndefDbgValue = [&](MachineInstr &MI) {
1178     const MCInstrDesc &RefII = TII->get(TargetOpcode::DBG_VALUE);
1179     MI.setDesc(RefII);
1180     MI.getOperand(0).setReg(0);
1181     MI.getOperand(1).ChangeToRegister(0, false);
1182   };
1183
1184   if (!useDebugInstrRef())
1185     return;
1186
1187   for (auto &MBB : *this) {
1188     for (auto &MI : MBB) {
1189       if (!MI.isDebugRef() || !MI.getOperand(0).isReg())
1190         continue;
1191
1192       Register Reg = MI.getOperand(0).getReg();
1193
1194       // Some vregs can be deleted as redundant in the meantime. Mark those
1195       // as DBG_VALUE $noreg. Additionally, some normal instructions are
1196       // quickly deleted, leaving dangling references to vregs with no def.
1197       if (Reg == 0 || !RegInfo->hasOneDef(Reg)) {
1198         MakeUndefDbgValue(MI);
1199         continue;
1200       }
1201
1202       assert(Reg.isVirtual());
1203       MachineInstr &DefMI = *RegInfo->def_instr_begin(Reg);
1204
1205       // If we've found a copy-like instruction, follow it back to the
1206       // instruction that defines the source value, see salvageCopySSA docs
1207       // for why this is important.
1208       if (DefMI.isCopyLike() || TII->isCopyInstr(DefMI)) {
1209         auto Result = salvageCopySSA(DefMI);
1210         MI.getOperand(0).ChangeToImmediate(Result.first);
1211         MI.getOperand(1).setImm(Result.second);
1212       } else {
1213         // Otherwise, identify the operand number that the VReg refers to.
1214         unsigned OperandIdx = 0;
1215         for (const auto &MO : DefMI.operands()) {
1216           if (MO.isReg() && MO.isDef() && MO.getReg() == Reg)
1217             break;
1218           ++OperandIdx;
1219         }
1220         assert(OperandIdx < DefMI.getNumOperands());
1221
1222         // Morph this instr ref to point at the given instruction and operand.
1223         unsigned ID = DefMI.getDebugInstrNum();
1224         MI.getOperand(0).ChangeToImmediate(ID);
1225         MI.getOperand(1).setImm(OperandIdx);
1226       }
1227     }
1228   }
1229 }
1230
1231 bool MachineFunction::useDebugInstrRef() const {
1232   // Disable instr-ref at -O0: it's very slow (in compile time). We can still
1233   // have optimized code inlined into this unoptimized code, however with
1234   // fewer and less aggressive optimizations happening, coverage and accuracy
1235   // should not suffer.
1236   if (getTarget().getOptLevel() == CodeGenOpt::None)
1237     return false;
1238
1239   // Don't use instr-ref if this function is marked optnone.
1240   if (F.hasFnAttribute(Attribute::OptimizeNone))
1241     return false;
1242
1243   if (llvm::debuginfoShouldUseDebugInstrRef(getTarget().getTargetTriple()))
1244     return true;
1245
1246   return false;
1247 }
1248
1249 // Use one million as a high / reserved number.
1250 const unsigned MachineFunction::DebugOperandMemNumber = 1000000;
1251
1252 /// \}
1253
1254 //===----------------------------------------------------------------------===//
1255 //  MachineJumpTableInfo implementation
1256 //===----------------------------------------------------------------------===//
1257
1258 /// Return the size of each entry in the jump table.
1259 unsigned MachineJumpTableInfo::getEntrySize(const DataLayout &TD) const {
1260   // The size of a jump table entry is 4 bytes unless the entry is just the
1261   // address of a block, in which case it is the pointer size.
1262   switch (getEntryKind()) {
1263   case MachineJumpTableInfo::EK_BlockAddress:
1264     return TD.getPointerSize();
1265   case MachineJumpTableInfo::EK_GPRel64BlockAddress:
1266     return 8;
1267   case MachineJumpTableInfo::EK_GPRel32BlockAddress:
1268   case MachineJumpTableInfo::EK_LabelDifference32:
1269   case MachineJumpTableInfo::EK_Custom32:
1270     return 4;
1271   case MachineJumpTableInfo::EK_Inline:
1272     return 0;
1273   }
1274   llvm_unreachable("Unknown jump table encoding!");
1275 }
1276
1277 /// Return the alignment of each entry in the jump table.
1278 unsigned MachineJumpTableInfo::getEntryAlignment(const DataLayout &TD) const {
1279   // The alignment of a jump table entry is the alignment of int32 unless the
1280   // entry is just the address of a block, in which case it is the pointer
1281   // alignment.
1282   switch (getEntryKind()) {
1283   case MachineJumpTableInfo::EK_BlockAddress:
1284     return TD.getPointerABIAlignment(0).value();
1285   case MachineJumpTableInfo::EK_GPRel64BlockAddress:
1286     return TD.getABIIntegerTypeAlignment(64).value();
1287   case MachineJumpTableInfo::EK_GPRel32BlockAddress:
1288   case MachineJumpTableInfo::EK_LabelDifference32:
1289   case MachineJumpTableInfo::EK_Custom32:
1290     return TD.getABIIntegerTypeAlignment(32).value();
1291   case MachineJumpTableInfo::EK_Inline:
1292     return 1;
1293   }
1294   llvm_unreachable("Unknown jump table encoding!");
1295 }
1296
1297 /// Create a new jump table entry in the jump table info.
1298 unsigned MachineJumpTableInfo::createJumpTableIndex(
1299                                const std::vector<MachineBasicBlock*> &DestBBs) {
1300   assert(!DestBBs.empty() && "Cannot create an empty jump table!");
1301   JumpTables.push_back(MachineJumpTableEntry(DestBBs));
1302   return JumpTables.size()-1;
1303 }
1304
1305 /// If Old is the target of any jump tables, update the jump tables to branch
1306 /// to New instead.
1307 bool MachineJumpTableInfo::ReplaceMBBInJumpTables(MachineBasicBlock *Old,
1308                                                   MachineBasicBlock *New) {
1309   assert(Old != New && "Not making a change?");
1310   bool MadeChange = false;
1311   for (size_t i = 0, e = JumpTables.size(); i != e; ++i)
1312     ReplaceMBBInJumpTable(i, Old, New);
1313   return MadeChange;
1314 }
1315
1316 /// If MBB is present in any jump tables, remove it.
1317 bool MachineJumpTableInfo::RemoveMBBFromJumpTables(MachineBasicBlock *MBB) {
1318   bool MadeChange = false;
1319   for (MachineJumpTableEntry &JTE : JumpTables) {
1320     auto removeBeginItr = std::remove(JTE.MBBs.begin(), JTE.MBBs.end(), MBB);
1321     MadeChange |= (removeBeginItr != JTE.MBBs.end());
1322     JTE.MBBs.erase(removeBeginItr, JTE.MBBs.end());
1323   }
1324   return MadeChange;
1325 }
1326
1327 /// If Old is a target of the jump tables, update the jump table to branch to
1328 /// New instead.
1329 bool MachineJumpTableInfo::ReplaceMBBInJumpTable(unsigned Idx,
1330                                                  MachineBasicBlock *Old,
1331                                                  MachineBasicBlock *New) {
1332   assert(Old != New && "Not making a change?");
1333   bool MadeChange = false;
1334   MachineJumpTableEntry &JTE = JumpTables[Idx];
1335   for (MachineBasicBlock *&MBB : JTE.MBBs)
1336     if (MBB == Old) {
1337       MBB = New;
1338       MadeChange = true;
1339     }
1340   return MadeChange;
1341 }
1342
1343 void MachineJumpTableInfo::print(raw_ostream &OS) const {
1344   if (JumpTables.empty()) return;
1345
1346   OS << "Jump Tables:\n";
1347
1348   for (unsigned i = 0, e = JumpTables.size(); i != e; ++i) {
1349     OS << printJumpTableEntryReference(i) << ':';
1350     for (const MachineBasicBlock *MBB : JumpTables[i].MBBs)
1351       OS << ' ' << printMBBReference(*MBB);
1352     if (i != e)
1353       OS << '\n';
1354   }
1355
1356   OS << '\n';
1357 }
1358
1359 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
1360 LLVM_DUMP_METHOD void MachineJumpTableInfo::dump() const { print(dbgs()); }
1361 #endif
1362
1363 Printable llvm::printJumpTableEntryReference(unsigned Idx) {
1364   return Printable([Idx](raw_ostream &OS) { OS << "%jump-table." << Idx; });
1365 }
1366
1367 //===----------------------------------------------------------------------===//
1368 //  MachineConstantPool implementation
1369 //===----------------------------------------------------------------------===//
1370
1371 void MachineConstantPoolValue::anchor() {}
1372
1373 unsigned MachineConstantPoolValue::getSizeInBytes(const DataLayout &DL) const {
1374   return DL.getTypeAllocSize(Ty);
1375 }
1376
1377 unsigned MachineConstantPoolEntry::getSizeInBytes(const DataLayout &DL) const {
1378   if (isMachineConstantPoolEntry())
1379     return Val.MachineCPVal->getSizeInBytes(DL);
1380   return DL.getTypeAllocSize(Val.ConstVal->getType());
1381 }
1382
1383 bool MachineConstantPoolEntry::needsRelocation() const {
1384   if (isMachineConstantPoolEntry())
1385     return true;
1386   return Val.ConstVal->needsDynamicRelocation();
1387 }
1388
1389 SectionKind
1390 MachineConstantPoolEntry::getSectionKind(const DataLayout *DL) const {
1391   if (needsRelocation())
1392     return SectionKind::getReadOnlyWithRel();
1393   switch (getSizeInBytes(*DL)) {
1394   case 4:
1395     return SectionKind::getMergeableConst4();
1396   case 8:
1397     return SectionKind::getMergeableConst8();
1398   case 16:
1399     return SectionKind::getMergeableConst16();
1400   case 32:
1401     return SectionKind::getMergeableConst32();
1402   default:
1403     return SectionKind::getReadOnly();
1404   }
1405 }
1406
1407 MachineConstantPool::~MachineConstantPool() {
1408   // A constant may be a member of both Constants and MachineCPVsSharingEntries,
1409   // so keep track of which we've deleted to avoid double deletions.
1410   DenseSet<MachineConstantPoolValue*> Deleted;
1411   for (const MachineConstantPoolEntry &C : Constants)
1412     if (C.isMachineConstantPoolEntry()) {
1413       Deleted.insert(C.Val.MachineCPVal);
1414       delete C.Val.MachineCPVal;
1415     }
1416   for (MachineConstantPoolValue *CPV : MachineCPVsSharingEntries) {
1417     if (Deleted.count(CPV) == 0)
1418       delete CPV;
1419   }
1420 }
1421
1422 /// Test whether the given two constants can be allocated the same constant pool
1423 /// entry.
1424 static bool CanShareConstantPoolEntry(const Constant *A, const Constant *B,
1425                                       const DataLayout &DL) {
1426   // Handle the trivial case quickly.
1427   if (A == B) return true;
1428
1429   // If they have the same type but weren't the same constant, quickly
1430   // reject them.
1431   if (A->getType() == B->getType()) return false;
1432
1433   // We can't handle structs or arrays.
1434   if (isa<StructType>(A->getType()) || isa<ArrayType>(A->getType()) ||
1435       isa<StructType>(B->getType()) || isa<ArrayType>(B->getType()))
1436     return false;
1437
1438   // For now, only support constants with the same size.
1439   uint64_t StoreSize = DL.getTypeStoreSize(A->getType());
1440   if (StoreSize != DL.getTypeStoreSize(B->getType()) || StoreSize > 128)
1441     return false;
1442
1443   Type *IntTy = IntegerType::get(A->getContext(), StoreSize*8);
1444
1445   // Try constant folding a bitcast of both instructions to an integer.  If we
1446   // get two identical ConstantInt's, then we are good to share them.  We use
1447   // the constant folding APIs to do this so that we get the benefit of
1448   // DataLayout.
1449   if (isa<PointerType>(A->getType()))
1450     A = ConstantFoldCastOperand(Instruction::PtrToInt,
1451                                 const_cast<Constant *>(A), IntTy, DL);
1452   else if (A->getType() != IntTy)
1453     A = ConstantFoldCastOperand(Instruction::BitCast, const_cast<Constant *>(A),
1454                                 IntTy, DL);
1455   if (isa<PointerType>(B->getType()))
1456     B = ConstantFoldCastOperand(Instruction::PtrToInt,
1457                                 const_cast<Constant *>(B), IntTy, DL);
1458   else if (B->getType() != IntTy)
1459     B = ConstantFoldCastOperand(Instruction::BitCast, const_cast<Constant *>(B),
1460                                 IntTy, DL);
1461
1462   return A == B;
1463 }
1464
1465 /// Create a new entry in the constant pool or return an existing one.
1466 /// User must specify the log2 of the minimum required alignment for the object.
1467 unsigned MachineConstantPool::getConstantPoolIndex(const Constant *C,
1468                                                    Align Alignment) {
1469   if (Alignment > PoolAlignment) PoolAlignment = Alignment;
1470
1471   // Check to see if we already have this constant.
1472   //
1473   // FIXME, this could be made much more efficient for large constant pools.
1474   for (unsigned i = 0, e = Constants.size(); i != e; ++i)
1475     if (!Constants[i].isMachineConstantPoolEntry() &&
1476         CanShareConstantPoolEntry(Constants[i].Val.ConstVal, C, DL)) {
1477       if (Constants[i].getAlign() < Alignment)
1478         Constants[i].Alignment = Alignment;
1479       return i;
1480     }
1481
1482   Constants.push_back(MachineConstantPoolEntry(C, Alignment));
1483   return Constants.size()-1;
1484 }
1485
1486 unsigned MachineConstantPool::getConstantPoolIndex(MachineConstantPoolValue *V,
1487                                                    Align Alignment) {
1488   if (Alignment > PoolAlignment) PoolAlignment = Alignment;
1489
1490   // Check to see if we already have this constant.
1491   //
1492   // FIXME, this could be made much more efficient for large constant pools.
1493   int Idx = V->getExistingMachineCPValue(this, Alignment);
1494   if (Idx != -1) {
1495     MachineCPVsSharingEntries.insert(V);
1496     return (unsigned)Idx;
1497   }
1498
1499   Constants.push_back(MachineConstantPoolEntry(V, Alignment));
1500   return Constants.size()-1;
1501 }
1502
1503 void MachineConstantPool::print(raw_ostream &OS) const {
1504   if (Constants.empty()) return;
1505
1506   OS << "Constant Pool:\n";
1507   for (unsigned i = 0, e = Constants.size(); i != e; ++i) {
1508     OS << "  cp#" << i << ": ";
1509     if (Constants[i].isMachineConstantPoolEntry())
1510       Constants[i].Val.MachineCPVal->print(OS);
1511     else
1512       Constants[i].Val.ConstVal->printAsOperand(OS, /*PrintType=*/false);
1513     OS << ", align=" << Constants[i].getAlign().value();
1514     OS << "\n";
1515   }
1516 }
1517
1518 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
1519 LLVM_DUMP_METHOD void MachineConstantPool::dump() const { print(dbgs()); }
1520 #endif