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/TargetLowering.h"
  37 #include "llvm/CodeGen/TargetRegisterInfo.h"
  38 #include "llvm/CodeGen/TargetSubtargetInfo.h"
  39 #include "llvm/CodeGen/WasmEHFuncInfo.h"
  40 #include "llvm/CodeGen/WinEHFuncInfo.h"
  41 #include "llvm/Config/llvm-config.h"
  42 #include "llvm/IR/Attributes.h"
  43 #include "llvm/IR/BasicBlock.h"
  44 #include "llvm/IR/Constant.h"
  45 #include "llvm/IR/DataLayout.h"
  46 #include "llvm/IR/DerivedTypes.h"
  47 #include "llvm/IR/Function.h"
  48 #include "llvm/IR/GlobalValue.h"
  49 #include "llvm/IR/Instruction.h"
  50 #include "llvm/IR/Instructions.h"
  51 #include "llvm/IR/Metadata.h"
  52 #include "llvm/IR/Module.h"
  53 #include "llvm/IR/ModuleSlotTracker.h"
  54 #include "llvm/IR/Value.h"
  55 #include "llvm/MC/MCContext.h"
  56 #include "llvm/MC/MCSymbol.h"
  57 #include "llvm/MC/SectionKind.h"
  58 #include "llvm/Support/Casting.h"
  59 #include "llvm/Support/CommandLine.h"
  60 #include "llvm/Support/Compiler.h"
  61 #include "llvm/Support/DOTGraphTraits.h"
  62 #include "llvm/Support/Debug.h"
  63 #include "llvm/Support/ErrorHandling.h"
  64 #include "llvm/Support/GraphWriter.h"
  65 #include "llvm/Support/raw_ostream.h"
  66 #include "llvm/Target/TargetMachine.h"
  67 #include <algorithm>
  68 #include <cassert>
  69 #include <cstddef>
  70 #include <cstdint>
  71 #include <iterator>
  72 #include <string>
  73 #include <utility>
  74 #include <vector>
  75
  76 using namespace llvm;
  77
  78 #define DEBUG_TYPE "codegen"
  79
  80 static cl::opt<unsigned>
  81 AlignAllFunctions("align-all-functions",
  82                   cl::desc("Force the alignment of all functions."),
  83                   cl::init(0), cl::Hidden);
  84
  85 static const char *getPropertyName(MachineFunctionProperties::Property Prop) {
  86   using P = MachineFunctionProperties::Property;
  87
  88   switch(Prop) {
  89   case P::FailedISel: return "FailedISel";
  90   case P::IsSSA: return "IsSSA";
  91   case P::Legalized: return "Legalized";
  92   case P::NoPHIs: return "NoPHIs";
  93   case P::NoVRegs: return "NoVRegs";
  94   case P::RegBankSelected: return "RegBankSelected";
  95   case P::Selected: return "Selected";
  96   case P::TracksLiveness: return "TracksLiveness";
  97   }
  98   llvm_unreachable("Invalid machine function property");
  99 }
 100
 101 // Pin the vtable to this file.
 102 void MachineFunction::Delegate::anchor() {}
 103
 104 void MachineFunctionProperties::print(raw_ostream &OS) const {
 105   const char *Separator = "";
 106   for (BitVector::size_type I = 0; I < Properties.size(); ++I) {
 107     if (!Properties[I])
 108       continue;
 109     OS << Separator << getPropertyName(static_cast<Property>(I));
 110     Separator = ", ";
 111   }
 112 }
 113
 114 //===----------------------------------------------------------------------===//
 115 // MachineFunction implementation
 116 //===----------------------------------------------------------------------===//
 117
 118 // Out-of-line virtual method.
 119 MachineFunctionInfo::~MachineFunctionInfo() = default;
 120
 121 void ilist_alloc_traits<MachineBasicBlock>::deleteNode(MachineBasicBlock *MBB) {
 122   MBB->getParent()->DeleteMachineBasicBlock(MBB);
 123 }
 124
 125 static inline unsigned getFnStackAlignment(const TargetSubtargetInfo *STI,
 126                                            const Function &F) {
 127   if (F.hasFnAttribute(Attribute::StackAlignment))
 128     return F.getFnStackAlignment();
 129   return STI->getFrameLowering()->getStackAlignment();
 130 }
 131
 132 MachineFunction::MachineFunction(const Function &F,
 133                                  const LLVMTargetMachine &Target,
 134                                  const TargetSubtargetInfo &STI,
 135                                  unsigned FunctionNum, MachineModuleInfo &mmi)
 136     : F(F), Target(Target), STI(&STI), Ctx(mmi.getContext()), MMI(mmi) {
 137   FunctionNumber = FunctionNum;
 138   init();
 139 }
 140
 141 void MachineFunction::handleInsertion(MachineInstr &MI) {
 142   if (TheDelegate)
 143     TheDelegate->MF_HandleInsertion(MI);
 144 }
 145
 146 void MachineFunction::handleRemoval(MachineInstr &MI) {
 147   if (TheDelegate)
 148     TheDelegate->MF_HandleRemoval(MI);
 149 }
 150
 151 void MachineFunction::init() {
 152   // Assume the function starts in SSA form with correct liveness.
 153   Properties.set(MachineFunctionProperties::Property::IsSSA);
 154   Properties.set(MachineFunctionProperties::Property::TracksLiveness);
 155   if (STI->getRegisterInfo())
 156     RegInfo = new (Allocator) MachineRegisterInfo(this);
 157   else
 158     RegInfo = nullptr;
 159
 160   MFInfo = nullptr;
 161   // We can realign the stack if the target supports it and the user hasn't
 162   // explicitly asked us not to.
 163   bool CanRealignSP = STI->getFrameLowering()->isStackRealignable() &&
 164                       !F.hasFnAttribute("no-realign-stack");
 165   FrameInfo = new (Allocator) MachineFrameInfo(
 166       getFnStackAlignment(STI, F), /*StackRealignable=*/CanRealignSP,
 167       /*ForceRealign=*/CanRealignSP &&
 168           F.hasFnAttribute(Attribute::StackAlignment));
 169
 170   if (F.hasFnAttribute(Attribute::StackAlignment))
 171     FrameInfo->ensureMaxAlignment(F.getFnStackAlignment());
 172
 173   ConstantPool = new (Allocator) MachineConstantPool(getDataLayout());
 174   Alignment = STI->getTargetLowering()->getMinFunctionAlignment();
 175
 176   // FIXME: Shouldn't use pref alignment if explicit alignment is set on F.
 177   // FIXME: Use Function::optForSize().
 178   if (!F.hasFnAttribute(Attribute::OptimizeForSize))
 179     Alignment = std::max(Alignment,
 180                          STI->getTargetLowering()->getPrefFunctionAlignment());
 181
 182   if (AlignAllFunctions)
 183     Alignment = AlignAllFunctions;
 184
 185   JumpTableInfo = nullptr;
 186
 187   if (isFuncletEHPersonality(classifyEHPersonality(
 188           F.hasPersonalityFn() ? F.getPersonalityFn() : nullptr))) {
 189     WinEHInfo = new (Allocator) WinEHFuncInfo();
 190   }
 191
 192   if (isScopedEHPersonality(classifyEHPersonality(
 193           F.hasPersonalityFn() ? F.getPersonalityFn() : nullptr))) {
 194     WasmEHInfo = new (Allocator) WasmEHFuncInfo();
 195   }
 196
 197   assert(Target.isCompatibleDataLayout(getDataLayout()) &&
 198          "Can't create a MachineFunction using a Module with a "
 199          "Target-incompatible DataLayout attached\n");
 200
 201   PSVManager =
 202     llvm::make_unique<PseudoSourceValueManager>(*(getSubtarget().
 203                                                   getInstrInfo()));
 204 }
 205
 206 MachineFunction::~MachineFunction() {
 207   clear();
 208 }
 209
 210 void MachineFunction::clear() {
 211   Properties.reset();
 212   // Don't call destructors on MachineInstr and MachineOperand. All of their
 213   // memory comes from the BumpPtrAllocator which is about to be purged.
 214   //
 215   // Do call MachineBasicBlock destructors, it contains std::vectors.
 216   for (iterator I = begin(), E = end(); I != E; I = BasicBlocks.erase(I))
 217     I->Insts.clearAndLeakNodesUnsafely();
 218   MBBNumbering.clear();
 219
 220   InstructionRecycler.clear(Allocator);
 221   OperandRecycler.clear(Allocator);
 222   BasicBlockRecycler.clear(Allocator);
 223   CodeViewAnnotations.clear();
 224   VariableDbgInfos.clear();
 225   if (RegInfo) {
 226     RegInfo->~MachineRegisterInfo();
 227     Allocator.Deallocate(RegInfo);
 228   }
 229   if (MFInfo) {
 230     MFInfo->~MachineFunctionInfo();
 231     Allocator.Deallocate(MFInfo);
 232   }
 233
 234   FrameInfo->~MachineFrameInfo();
 235   Allocator.Deallocate(FrameInfo);
 236
 237   ConstantPool->~MachineConstantPool();
 238   Allocator.Deallocate(ConstantPool);
 239
 240   if (JumpTableInfo) {
 241     JumpTableInfo->~MachineJumpTableInfo();
 242     Allocator.Deallocate(JumpTableInfo);
 243   }
 244
 245   if (WinEHInfo) {
 246     WinEHInfo->~WinEHFuncInfo();
 247     Allocator.Deallocate(WinEHInfo);
 248   }
 249
 250   if (WasmEHInfo) {
 251     WasmEHInfo->~WasmEHFuncInfo();
 252     Allocator.Deallocate(WasmEHInfo);
 253   }
 254 }
 255
 256 const DataLayout &MachineFunction::getDataLayout() const {
 257   return F.getParent()->getDataLayout();
 258 }
 259
 260 /// Get the JumpTableInfo for this function.
 261 /// If it does not already exist, allocate one.
 262 MachineJumpTableInfo *MachineFunction::
 263 getOrCreateJumpTableInfo(unsigned EntryKind) {
 264   if (JumpTableInfo) return JumpTableInfo;
 265
 266   JumpTableInfo = new (Allocator)
 267     MachineJumpTableInfo((MachineJumpTableInfo::JTEntryKind)EntryKind);
 268   return JumpTableInfo;
 269 }
 270
 271 /// Should we be emitting segmented stack stuff for the function
 272 bool MachineFunction::shouldSplitStack() const {
 273   return getFunction().hasFnAttribute("split-stack");
 274 }
 275
 276 /// This discards all of the MachineBasicBlock numbers and recomputes them.
 277 /// This guarantees that the MBB numbers are sequential, dense, and match the
 278 /// ordering of the blocks within the function.  If a specific MachineBasicBlock
 279 /// is specified, only that block and those after it are renumbered.
 280 void MachineFunction::RenumberBlocks(MachineBasicBlock *MBB) {
 281   if (empty()) { MBBNumbering.clear(); return; }
 282   MachineFunction::iterator MBBI, E = end();
 283   if (MBB == nullptr)
 284     MBBI = begin();
 285   else
 286     MBBI = MBB->getIterator();
 287
 288   // Figure out the block number this should have.
 289   unsigned BlockNo = 0;
 290   if (MBBI != begin())
 291     BlockNo = std::prev(MBBI)->getNumber() + 1;
 292
 293   for (; MBBI != E; ++MBBI, ++BlockNo) {
 294     if (MBBI->getNumber() != (int)BlockNo) {
 295       // Remove use of the old number.
 296       if (MBBI->getNumber() != -1) {
 297         assert(MBBNumbering[MBBI->getNumber()] == &*MBBI &&
 298                "MBB number mismatch!");
 299         MBBNumbering[MBBI->getNumber()] = nullptr;
 300       }
 301
 302       // If BlockNo is already taken, set that block's number to -1.
 303       if (MBBNumbering[BlockNo])
 304         MBBNumbering[BlockNo]->setNumber(-1);
 305
 306       MBBNumbering[BlockNo] = &*MBBI;
 307       MBBI->setNumber(BlockNo);
 308     }
 309   }
 310
 311   // Okay, all the blocks are renumbered.  If we have compactified the block
 312   // numbering, shrink MBBNumbering now.
 313   assert(BlockNo <= MBBNumbering.size() && "Mismatch!");
 314   MBBNumbering.resize(BlockNo);
 315 }
 316
 317 /// Allocate a new MachineInstr. Use this instead of `new MachineInstr'.
 318 MachineInstr *MachineFunction::CreateMachineInstr(const MCInstrDesc &MCID,
 319                                                   const DebugLoc &DL,
 320                                                   bool NoImp) {
 321   return new (InstructionRecycler.Allocate<MachineInstr>(Allocator))
 322     MachineInstr(*this, MCID, DL, NoImp);
 323 }
 324
 325 /// Create a new MachineInstr which is a copy of the 'Orig' instruction,
 326 /// identical in all ways except the instruction has no parent, prev, or next.
 327 MachineInstr *
 328 MachineFunction::CloneMachineInstr(const MachineInstr *Orig) {
 329   return new (InstructionRecycler.Allocate<MachineInstr>(Allocator))
 330              MachineInstr(*this, *Orig);
 331 }
 332
 333 MachineInstr &MachineFunction::CloneMachineInstrBundle(MachineBasicBlock &MBB,
 334     MachineBasicBlock::iterator InsertBefore, const MachineInstr &Orig) {
 335   MachineInstr *FirstClone = nullptr;
 336   MachineBasicBlock::const_instr_iterator I = Orig.getIterator();
 337   while (true) {
 338     MachineInstr *Cloned = CloneMachineInstr(&*I);
 339     MBB.insert(InsertBefore, Cloned);
 340     if (FirstClone == nullptr) {
 341       FirstClone = Cloned;
 342     } else {
 343       Cloned->bundleWithPred();
 344     }
 345
 346     if (!I->isBundledWithSucc())
 347       break;
 348     ++I;
 349   }
 350   return *FirstClone;
 351 }
 352
 353 /// Delete the given MachineInstr.
 354 ///
 355 /// This function also serves as the MachineInstr destructor - the real
 356 /// ~MachineInstr() destructor must be empty.
 357 void
 358 MachineFunction::DeleteMachineInstr(MachineInstr *MI) {
 359   // Strip it for parts. The operand array and the MI object itself are
 360   // independently recyclable.
 361   if (MI->Operands)
 362     deallocateOperandArray(MI->CapOperands, MI->Operands);
 363   // Don't call ~MachineInstr() which must be trivial anyway because
 364   // ~MachineFunction drops whole lists of MachineInstrs wihout calling their
 365   // destructors.
 366   InstructionRecycler.Deallocate(Allocator, MI);
 367 }
 368
 369 /// Allocate a new MachineBasicBlock. Use this instead of
 370 /// `new MachineBasicBlock'.
 371 MachineBasicBlock *
 372 MachineFunction::CreateMachineBasicBlock(const BasicBlock *bb) {
 373   return new (BasicBlockRecycler.Allocate<MachineBasicBlock>(Allocator))
 374              MachineBasicBlock(*this, bb);
 375 }
 376
 377 /// Delete the given MachineBasicBlock.
 378 void
 379 MachineFunction::DeleteMachineBasicBlock(MachineBasicBlock *MBB) {
 380   assert(MBB->getParent() == this && "MBB parent mismatch!");
 381   MBB->~MachineBasicBlock();
 382   BasicBlockRecycler.Deallocate(Allocator, MBB);
 383 }
 384
 385 MachineMemOperand *MachineFunction::getMachineMemOperand(
 386     MachinePointerInfo PtrInfo, MachineMemOperand::Flags f, uint64_t s,
 387     unsigned base_alignment, const AAMDNodes &AAInfo, const MDNode *Ranges,
 388     SyncScope::ID SSID, AtomicOrdering Ordering,
 389     AtomicOrdering FailureOrdering) {
 390   return new (Allocator)
 391       MachineMemOperand(PtrInfo, f, s, base_alignment, AAInfo, Ranges,
 392                         SSID, Ordering, FailureOrdering);
 393 }
 394
 395 MachineMemOperand *
 396 MachineFunction::getMachineMemOperand(const MachineMemOperand *MMO,
 397                                       int64_t Offset, uint64_t Size) {
 398   const MachinePointerInfo &PtrInfo = MMO->getPointerInfo();
 399
 400   // If there is no pointer value, the offset isn't tracked so we need to adjust
 401   // the base alignment.
 402   unsigned Align = PtrInfo.V.isNull()
 403                        ? MinAlign(MMO->getBaseAlignment(), Offset)
 404                        : MMO->getBaseAlignment();
 405
 406   return new (Allocator)
 407       MachineMemOperand(PtrInfo.getWithOffset(Offset), MMO->getFlags(), Size,
 408                         Align, AAMDNodes(), nullptr, MMO->getSyncScopeID(),
 409                         MMO->getOrdering(), MMO->getFailureOrdering());
 410 }
 411
 412 MachineMemOperand *
 413 MachineFunction::getMachineMemOperand(const MachineMemOperand *MMO,
 414                                       const AAMDNodes &AAInfo) {
 415   MachinePointerInfo MPI = MMO->getValue() ?
 416              MachinePointerInfo(MMO->getValue(), MMO->getOffset()) :
 417              MachinePointerInfo(MMO->getPseudoValue(), MMO->getOffset());
 418
 419   return new (Allocator)
 420              MachineMemOperand(MPI, MMO->getFlags(), MMO->getSize(),
 421                                MMO->getBaseAlignment(), AAInfo,
 422                                MMO->getRanges(), MMO->getSyncScopeID(),
 423                                MMO->getOrdering(), MMO->getFailureOrdering());
 424 }
 425
 426 MachineInstr::ExtraInfo *
 427 MachineFunction::createMIExtraInfo(ArrayRef<MachineMemOperand *> MMOs,
 428                                    MCSymbol *PreInstrSymbol,
 429                                    MCSymbol *PostInstrSymbol) {
 430   return MachineInstr::ExtraInfo::create(Allocator, MMOs, PreInstrSymbol,
 431                                          PostInstrSymbol);
 432 }
 433
 434 const char *MachineFunction::createExternalSymbolName(StringRef Name) {
 435   char *Dest = Allocator.Allocate<char>(Name.size() + 1);
 436   llvm::copy(Name, Dest);
 437   Dest[Name.size()] = 0;
 438   return Dest;
 439 }
 440
 441 uint32_t *MachineFunction::allocateRegMask() {
 442   unsigned NumRegs = getSubtarget().getRegisterInfo()->getNumRegs();
 443   unsigned Size = MachineOperand::getRegMaskSize(NumRegs);
 444   uint32_t *Mask = Allocator.Allocate<uint32_t>(Size);
 445   memset(Mask, 0, Size * sizeof(Mask[0]));
 446   return Mask;
 447 }
 448
 449 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
 450 LLVM_DUMP_METHOD void MachineFunction::dump() const {
 451   print(dbgs());
 452 }
 453 #endif
 454
 455 StringRef MachineFunction::getName() const {
 456   return getFunction().getName();
 457 }
 458
 459 void MachineFunction::print(raw_ostream &OS, const SlotIndexes *Indexes) const {
 460   OS << "# Machine code for function " << getName() << ": ";
 461   getProperties().print(OS);
 462   OS << '\n';
 463
 464   // Print Frame Information
 465   FrameInfo->print(*this, OS);
 466
 467   // Print JumpTable Information
 468   if (JumpTableInfo)
 469     JumpTableInfo->print(OS);
 470
 471   // Print Constant Pool
 472   ConstantPool->print(OS);
 473
 474   const TargetRegisterInfo *TRI = getSubtarget().getRegisterInfo();
 475
 476   if (RegInfo && !RegInfo->livein_empty()) {
 477     OS << "Function Live Ins: ";
 478     for (MachineRegisterInfo::livein_iterator
 479          I = RegInfo->livein_begin(), E = RegInfo->livein_end(); I != E; ++I) {
 480       OS << printReg(I->first, TRI);
 481       if (I->second)
 482         OS << " in " << printReg(I->second, TRI);
 483       if (std::next(I) != E)
 484         OS << ", ";
 485     }
 486     OS << '\n';
 487   }
 488
 489   ModuleSlotTracker MST(getFunction().getParent());
 490   MST.incorporateFunction(getFunction());
 491   for (const auto &BB : *this) {
 492     OS << '\n';
 493     // If we print the whole function, print it at its most verbose level.
 494     BB.print(OS, MST, Indexes, /*IsStandalone=*/true);
 495   }
 496
 497   OS << "\n# End machine code for function " << getName() << ".\n\n";
 498 }
 499
 500 namespace llvm {
 501
 502   template<>
 503   struct DOTGraphTraits<const MachineFunction*> : public DefaultDOTGraphTraits {
 504     DOTGraphTraits(bool isSimple = false) : DefaultDOTGraphTraits(isSimple) {}
 505
 506     static std::string getGraphName(const MachineFunction *F) {
 507       return ("CFG for '" + F->getName() + "' function").str();
 508     }
 509
 510     std::string getNodeLabel(const MachineBasicBlock *Node,
 511                              const MachineFunction *Graph) {
 512       std::string OutStr;
 513       {
 514         raw_string_ostream OSS(OutStr);
 515
 516         if (isSimple()) {
 517           OSS << printMBBReference(*Node);
 518           if (const BasicBlock *BB = Node->getBasicBlock())
 519             OSS << ": " << BB->getName();
 520         } else
 521           Node->print(OSS);
 522       }
 523
 524       if (OutStr[0] == '\n') OutStr.erase(OutStr.begin());
 525
 526       // Process string output to make it nicer...
 527       for (unsigned i = 0; i != OutStr.length(); ++i)
 528         if (OutStr[i] == '\n') {                            // Left justify
 529           OutStr[i] = '\\';
 530           OutStr.insert(OutStr.begin()+i+1, 'l');
 531         }
 532       return OutStr;
 533     }
 534   };
 535
 536 } // end namespace llvm
 537
 538 void MachineFunction::viewCFG() const
 539 {
 540 #ifndef NDEBUG
 541   ViewGraph(this, "mf" + getName());
 542 #else
 543   errs() << "MachineFunction::viewCFG is only available in debug builds on "
 544          << "systems with Graphviz or gv!\n";
 545 #endif // NDEBUG
 546 }
 547
 548 void MachineFunction::viewCFGOnly() const
 549 {
 550 #ifndef NDEBUG
 551   ViewGraph(this, "mf" + getName(), true);
 552 #else
 553   errs() << "MachineFunction::viewCFGOnly is only available in debug builds on "
 554          << "systems with Graphviz or gv!\n";
 555 #endif // NDEBUG
 556 }
 557
 558 /// Add the specified physical register as a live-in value and
 559 /// create a corresponding virtual register for it.
 560 unsigned MachineFunction::addLiveIn(unsigned PReg,
 561                                     const TargetRegisterClass *RC) {
 562   MachineRegisterInfo &MRI = getRegInfo();
 563   unsigned VReg = MRI.getLiveInVirtReg(PReg);
 564   if (VReg) {
 565     const TargetRegisterClass *VRegRC = MRI.getRegClass(VReg);
 566     (void)VRegRC;
 567     // A physical register can be added several times.
 568     // Between two calls, the register class of the related virtual register
 569     // may have been constrained to match some operation constraints.
 570     // In that case, check that the current register class includes the
 571     // physical register and is a sub class of the specified RC.
 572     assert((VRegRC == RC || (VRegRC->contains(PReg) &&
 573                              RC->hasSubClassEq(VRegRC))) &&
 574             "Register class mismatch!");
 575     return VReg;
 576   }
 577   VReg = MRI.createVirtualRegister(RC);
 578   MRI.addLiveIn(PReg, VReg);
 579   return VReg;
 580 }
 581
 582 /// Return the MCSymbol for the specified non-empty jump table.
 583 /// If isLinkerPrivate is specified, an 'l' label is returned, otherwise a
 584 /// normal 'L' label is returned.
 585 MCSymbol *MachineFunction::getJTISymbol(unsigned JTI, MCContext &Ctx,
 586                                         bool isLinkerPrivate) const {
 587   const DataLayout &DL = getDataLayout();
 588   assert(JumpTableInfo && "No jump tables");
 589   assert(JTI < JumpTableInfo->getJumpTables().size() && "Invalid JTI!");
 590
 591   StringRef Prefix = isLinkerPrivate ? DL.getLinkerPrivateGlobalPrefix()
 592                                      : DL.getPrivateGlobalPrefix();
 593   SmallString<60> Name;
 594   raw_svector_ostream(Name)
 595     << Prefix << "JTI" << getFunctionNumber() << '_' << JTI;
 596   return Ctx.getOrCreateSymbol(Name);
 597 }
 598
 599 /// Return a function-local symbol to represent the PIC base.
 600 MCSymbol *MachineFunction::getPICBaseSymbol() const {
 601   const DataLayout &DL = getDataLayout();
 602   return Ctx.getOrCreateSymbol(Twine(DL.getPrivateGlobalPrefix()) +
 603                                Twine(getFunctionNumber()) + "$pb");
 604 }
 605
 606 /// \name Exception Handling
 607 /// \{
 608
 609 LandingPadInfo &
 610 MachineFunction::getOrCreateLandingPadInfo(MachineBasicBlock *LandingPad) {
 611   unsigned N = LandingPads.size();
 612   for (unsigned i = 0; i < N; ++i) {
 613     LandingPadInfo &LP = LandingPads[i];
 614     if (LP.LandingPadBlock == LandingPad)
 615       return LP;
 616   }
 617
 618   LandingPads.push_back(LandingPadInfo(LandingPad));
 619   return LandingPads[N];
 620 }
 621
 622 void MachineFunction::addInvoke(MachineBasicBlock *LandingPad,
 623                                 MCSymbol *BeginLabel, MCSymbol *EndLabel) {
 624   LandingPadInfo &LP = getOrCreateLandingPadInfo(LandingPad);
 625   LP.BeginLabels.push_back(BeginLabel);
 626   LP.EndLabels.push_back(EndLabel);
 627 }
 628
 629 MCSymbol *MachineFunction::addLandingPad(MachineBasicBlock *LandingPad) {
 630   MCSymbol *LandingPadLabel = Ctx.createTempSymbol();
 631   LandingPadInfo &LP = getOrCreateLandingPadInfo(LandingPad);
 632   LP.LandingPadLabel = LandingPadLabel;
 633
 634   const Instruction *FirstI = LandingPad->getBasicBlock()->getFirstNonPHI();
 635   if (const auto *LPI = dyn_cast<LandingPadInst>(FirstI)) {
 636     if (const auto *PF =
 637             dyn_cast<Function>(F.getPersonalityFn()->stripPointerCasts()))
 638       getMMI().addPersonality(PF);
 639
 640     if (LPI->isCleanup())
 641       addCleanup(LandingPad);
 642
 643     // FIXME: New EH - Add the clauses in reverse order. This isn't 100%
 644     //        correct, but we need to do it this way because of how the DWARF EH
 645     //        emitter processes the clauses.
 646     for (unsigned I = LPI->getNumClauses(); I != 0; --I) {
 647       Value *Val = LPI->getClause(I - 1);
 648       if (LPI->isCatch(I - 1)) {
 649         addCatchTypeInfo(LandingPad,
 650                          dyn_cast<GlobalValue>(Val->stripPointerCasts()));
 651       } else {
 652         // Add filters in a list.
 653         auto *CVal = cast<Constant>(Val);
 654         SmallVector<const GlobalValue *, 4> FilterList;
 655         for (User::op_iterator II = CVal->op_begin(), IE = CVal->op_end();
 656              II != IE; ++II)
 657           FilterList.push_back(cast<GlobalValue>((*II)->stripPointerCasts()));
 658
 659         addFilterTypeInfo(LandingPad, FilterList);
 660       }
 661     }
 662
 663   } else if (const auto *CPI = dyn_cast<CatchPadInst>(FirstI)) {
 664     for (unsigned I = CPI->getNumArgOperands(); I != 0; --I) {
 665       Value *TypeInfo = CPI->getArgOperand(I - 1)->stripPointerCasts();
 666       addCatchTypeInfo(LandingPad, dyn_cast<GlobalValue>(TypeInfo));
 667     }
 668
 669   } else {
 670     assert(isa<CleanupPadInst>(FirstI) && "Invalid landingpad!");
 671   }
 672
 673   return LandingPadLabel;
 674 }
 675
 676 void MachineFunction::addCatchTypeInfo(MachineBasicBlock *LandingPad,
 677                                        ArrayRef<const GlobalValue *> TyInfo) {
 678   LandingPadInfo &LP = getOrCreateLandingPadInfo(LandingPad);
 679   for (unsigned N = TyInfo.size(); N; --N)
 680     LP.TypeIds.push_back(getTypeIDFor(TyInfo[N - 1]));
 681 }
 682
 683 void MachineFunction::addFilterTypeInfo(MachineBasicBlock *LandingPad,
 684                                         ArrayRef<const GlobalValue *> TyInfo) {
 685   LandingPadInfo &LP = getOrCreateLandingPadInfo(LandingPad);
 686   std::vector<unsigned> IdsInFilter(TyInfo.size());
 687   for (unsigned I = 0, E = TyInfo.size(); I != E; ++I)
 688     IdsInFilter[I] = getTypeIDFor(TyInfo[I]);
 689   LP.TypeIds.push_back(getFilterIDFor(IdsInFilter));
 690 }
 691
 692 void MachineFunction::tidyLandingPads(DenseMap<MCSymbol *, uintptr_t> *LPMap,
 693                                       bool TidyIfNoBeginLabels) {
 694   for (unsigned i = 0; i != LandingPads.size(); ) {
 695     LandingPadInfo &LandingPad = LandingPads[i];
 696     if (LandingPad.LandingPadLabel &&
 697         !LandingPad.LandingPadLabel->isDefined() &&
 698         (!LPMap || (*LPMap)[LandingPad.LandingPadLabel] == 0))
 699       LandingPad.LandingPadLabel = nullptr;
 700
 701     // Special case: we *should* emit LPs with null LP MBB. This indicates
 702     // "nounwind" case.
 703     if (!LandingPad.LandingPadLabel && LandingPad.LandingPadBlock) {
 704       LandingPads.erase(LandingPads.begin() + i);
 705       continue;
 706     }
 707
 708     if (TidyIfNoBeginLabels) {
 709       for (unsigned j = 0, e = LandingPads[i].BeginLabels.size(); j != e; ++j) {
 710         MCSymbol *BeginLabel = LandingPad.BeginLabels[j];
 711         MCSymbol *EndLabel = LandingPad.EndLabels[j];
 712         if ((BeginLabel->isDefined() || (LPMap && (*LPMap)[BeginLabel] != 0)) &&
 713             (EndLabel->isDefined() || (LPMap && (*LPMap)[EndLabel] != 0)))
 714           continue;
 715
 716         LandingPad.BeginLabels.erase(LandingPad.BeginLabels.begin() + j);
 717         LandingPad.EndLabels.erase(LandingPad.EndLabels.begin() + j);
 718         --j;
 719         --e;
 720       }
 721
 722       // Remove landing pads with no try-ranges.
 723       if (LandingPads[i].BeginLabels.empty()) {
 724         LandingPads.erase(LandingPads.begin() + i);
 725         continue;
 726       }
 727     }
 728
 729     // If there is no landing pad, ensure that the list of typeids is empty.
 730     // If the only typeid is a cleanup, this is the same as having no typeids.
 731     if (!LandingPad.LandingPadBlock ||
 732         (LandingPad.TypeIds.size() == 1 && !LandingPad.TypeIds[0]))
 733       LandingPad.TypeIds.clear();
 734     ++i;
 735   }
 736 }
 737
 738 void MachineFunction::addCleanup(MachineBasicBlock *LandingPad) {
 739   LandingPadInfo &LP = getOrCreateLandingPadInfo(LandingPad);
 740   LP.TypeIds.push_back(0);
 741 }
 742
 743 void MachineFunction::addSEHCatchHandler(MachineBasicBlock *LandingPad,
 744                                          const Function *Filter,
 745                                          const BlockAddress *RecoverBA) {
 746   LandingPadInfo &LP = getOrCreateLandingPadInfo(LandingPad);
 747   SEHHandler Handler;
 748   Handler.FilterOrFinally = Filter;
 749   Handler.RecoverBA = RecoverBA;
 750   LP.SEHHandlers.push_back(Handler);
 751 }
 752
 753 void MachineFunction::addSEHCleanupHandler(MachineBasicBlock *LandingPad,
 754                                            const Function *Cleanup) {
 755   LandingPadInfo &LP = getOrCreateLandingPadInfo(LandingPad);
 756   SEHHandler Handler;
 757   Handler.FilterOrFinally = Cleanup;
 758   Handler.RecoverBA = nullptr;
 759   LP.SEHHandlers.push_back(Handler);
 760 }
 761
 762 void MachineFunction::setCallSiteLandingPad(MCSymbol *Sym,
 763                                             ArrayRef<unsigned> Sites) {
 764   LPadToCallSiteMap[Sym].append(Sites.begin(), Sites.end());
 765 }
 766
 767 unsigned MachineFunction::getTypeIDFor(const GlobalValue *TI) {
 768   for (unsigned i = 0, N = TypeInfos.size(); i != N; ++i)
 769     if (TypeInfos[i] == TI) return i + 1;
 770
 771   TypeInfos.push_back(TI);
 772   return TypeInfos.size();
 773 }
 774
 775 int MachineFunction::getFilterIDFor(std::vector<unsigned> &TyIds) {
 776   // If the new filter coincides with the tail of an existing filter, then
 777   // re-use the existing filter.  Folding filters more than this requires
 778   // re-ordering filters and/or their elements - probably not worth it.
 779   for (std::vector<unsigned>::iterator I = FilterEnds.begin(),
 780        E = FilterEnds.end(); I != E; ++I) {
 781     unsigned i = *I, j = TyIds.size();
 782
 783     while (i && j)
 784       if (FilterIds[--i] != TyIds[--j])
 785         goto try_next;
 786
 787     if (!j)
 788       // The new filter coincides with range [i, end) of the existing filter.
 789       return -(1 + i);
 790
 791 try_next:;
 792   }
 793
 794   // Add the new filter.
 795   int FilterID = -(1 + FilterIds.size());
 796   FilterIds.reserve(FilterIds.size() + TyIds.size() + 1);
 797   FilterIds.insert(FilterIds.end(), TyIds.begin(), TyIds.end());
 798   FilterEnds.push_back(FilterIds.size());
 799   FilterIds.push_back(0); // terminator
 800   return FilterID;
 801 }
 802
 803 /// \}
 804
 805 //===----------------------------------------------------------------------===//
 806 //  MachineJumpTableInfo implementation
 807 //===----------------------------------------------------------------------===//
 808
 809 /// Return the size of each entry in the jump table.
 810 unsigned MachineJumpTableInfo::getEntrySize(const DataLayout &TD) const {
 811   // The size of a jump table entry is 4 bytes unless the entry is just the
 812   // address of a block, in which case it is the pointer size.
 813   switch (getEntryKind()) {
 814   case MachineJumpTableInfo::EK_BlockAddress:
 815     return TD.getPointerSize();
 816   case MachineJumpTableInfo::EK_GPRel64BlockAddress:
 817     return 8;
 818   case MachineJumpTableInfo::EK_GPRel32BlockAddress:
 819   case MachineJumpTableInfo::EK_LabelDifference32:
 820   case MachineJumpTableInfo::EK_Custom32:
 821     return 4;
 822   case MachineJumpTableInfo::EK_Inline:
 823     return 0;
 824   }
 825   llvm_unreachable("Unknown jump table encoding!");
 826 }
 827
 828 /// Return the alignment of each entry in the jump table.
 829 unsigned MachineJumpTableInfo::getEntryAlignment(const DataLayout &TD) const {
 830   // The alignment of a jump table entry is the alignment of int32 unless the
 831   // entry is just the address of a block, in which case it is the pointer
 832   // alignment.
 833   switch (getEntryKind()) {
 834   case MachineJumpTableInfo::EK_BlockAddress:
 835     return TD.getPointerABIAlignment(0);
 836   case MachineJumpTableInfo::EK_GPRel64BlockAddress:
 837     return TD.getABIIntegerTypeAlignment(64);
 838   case MachineJumpTableInfo::EK_GPRel32BlockAddress:
 839   case MachineJumpTableInfo::EK_LabelDifference32:
 840   case MachineJumpTableInfo::EK_Custom32:
 841     return TD.getABIIntegerTypeAlignment(32);
 842   case MachineJumpTableInfo::EK_Inline:
 843     return 1;
 844   }
 845   llvm_unreachable("Unknown jump table encoding!");
 846 }
 847
 848 /// Create a new jump table entry in the jump table info.
 849 unsigned MachineJumpTableInfo::createJumpTableIndex(
 850                                const std::vector<MachineBasicBlock*> &DestBBs) {
 851   assert(!DestBBs.empty() && "Cannot create an empty jump table!");
 852   JumpTables.push_back(MachineJumpTableEntry(DestBBs));
 853   return JumpTables.size()-1;
 854 }
 855
 856 /// If Old is the target of any jump tables, update the jump tables to branch
 857 /// to New instead.
 858 bool MachineJumpTableInfo::ReplaceMBBInJumpTables(MachineBasicBlock *Old,
 859                                                   MachineBasicBlock *New) {
 860   assert(Old != New && "Not making a change?");
 861   bool MadeChange = false;
 862   for (size_t i = 0, e = JumpTables.size(); i != e; ++i)
 863     ReplaceMBBInJumpTable(i, Old, New);
 864   return MadeChange;
 865 }
 866
 867 /// If Old is a target of the jump tables, update the jump table to branch to
 868 /// New instead.
 869 bool MachineJumpTableInfo::ReplaceMBBInJumpTable(unsigned Idx,
 870                                                  MachineBasicBlock *Old,
 871                                                  MachineBasicBlock *New) {
 872   assert(Old != New && "Not making a change?");
 873   bool MadeChange = false;
 874   MachineJumpTableEntry &JTE = JumpTables[Idx];
 875   for (size_t j = 0, e = JTE.MBBs.size(); j != e; ++j)
 876     if (JTE.MBBs[j] == Old) {
 877       JTE.MBBs[j] = New;
 878       MadeChange = true;
 879     }
 880   return MadeChange;
 881 }
 882
 883 void MachineJumpTableInfo::print(raw_ostream &OS) const {
 884   if (JumpTables.empty()) return;
 885
 886   OS << "Jump Tables:\n";
 887
 888   for (unsigned i = 0, e = JumpTables.size(); i != e; ++i) {
 889     OS << printJumpTableEntryReference(i) << ": ";
 890     for (unsigned j = 0, f = JumpTables[i].MBBs.size(); j != f; ++j)
 891       OS << ' ' << printMBBReference(*JumpTables[i].MBBs[j]);
 892   }
 893
 894   OS << '\n';
 895 }
 896
 897 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
 898 LLVM_DUMP_METHOD void MachineJumpTableInfo::dump() const { print(dbgs()); }
 899 #endif
 900
 901 Printable llvm::printJumpTableEntryReference(unsigned Idx) {
 902   return Printable([Idx](raw_ostream &OS) { OS << "%jump-table." << Idx; });
 903 }
 904
 905 //===----------------------------------------------------------------------===//
 906 //  MachineConstantPool implementation
 907 //===----------------------------------------------------------------------===//
 908
 909 void MachineConstantPoolValue::anchor() {}
 910
 911 Type *MachineConstantPoolEntry::getType() const {
 912   if (isMachineConstantPoolEntry())
 913     return Val.MachineCPVal->getType();
 914   return Val.ConstVal->getType();
 915 }
 916
 917 bool MachineConstantPoolEntry::needsRelocation() const {
 918   if (isMachineConstantPoolEntry())
 919     return true;
 920   return Val.ConstVal->needsRelocation();
 921 }
 922
 923 SectionKind
 924 MachineConstantPoolEntry::getSectionKind(const DataLayout *DL) const {
 925   if (needsRelocation())
 926     return SectionKind::getReadOnlyWithRel();
 927   switch (DL->getTypeAllocSize(getType())) {
 928   case 4:
 929     return SectionKind::getMergeableConst4();
 930   case 8:
 931     return SectionKind::getMergeableConst8();
 932   case 16:
 933     return SectionKind::getMergeableConst16();
 934   case 32:
 935     return SectionKind::getMergeableConst32();
 936   default:
 937     return SectionKind::getReadOnly();
 938   }
 939 }
 940
 941 MachineConstantPool::~MachineConstantPool() {
 942   // A constant may be a member of both Constants and MachineCPVsSharingEntries,
 943   // so keep track of which we've deleted to avoid double deletions.
 944   DenseSet<MachineConstantPoolValue*> Deleted;
 945   for (unsigned i = 0, e = Constants.size(); i != e; ++i)
 946     if (Constants[i].isMachineConstantPoolEntry()) {
 947       Deleted.insert(Constants[i].Val.MachineCPVal);
 948       delete Constants[i].Val.MachineCPVal;
 949     }
 950   for (DenseSet<MachineConstantPoolValue*>::iterator I =
 951        MachineCPVsSharingEntries.begin(), E = MachineCPVsSharingEntries.end();
 952        I != E; ++I) {
 953     if (Deleted.count(*I) == 0)
 954       delete *I;
 955   }
 956 }
 957
 958 /// Test whether the given two constants can be allocated the same constant pool
 959 /// entry.
 960 static bool CanShareConstantPoolEntry(const Constant *A, const Constant *B,
 961                                       const DataLayout &DL) {
 962   // Handle the trivial case quickly.
 963   if (A == B) return true;
 964
 965   // If they have the same type but weren't the same constant, quickly
 966   // reject them.
 967   if (A->getType() == B->getType()) return false;
 968
 969   // We can't handle structs or arrays.
 970   if (isa<StructType>(A->getType()) || isa<ArrayType>(A->getType()) ||
 971       isa<StructType>(B->getType()) || isa<ArrayType>(B->getType()))
 972     return false;
 973
 974   // For now, only support constants with the same size.
 975   uint64_t StoreSize = DL.getTypeStoreSize(A->getType());
 976   if (StoreSize != DL.getTypeStoreSize(B->getType()) || StoreSize > 128)
 977     return false;
 978
 979   Type *IntTy = IntegerType::get(A->getContext(), StoreSize*8);
 980
 981   // Try constant folding a bitcast of both instructions to an integer.  If we
 982   // get two identical ConstantInt's, then we are good to share them.  We use
 983   // the constant folding APIs to do this so that we get the benefit of
 984   // DataLayout.
 985   if (isa<PointerType>(A->getType()))
 986     A = ConstantFoldCastOperand(Instruction::PtrToInt,
 987                                 const_cast<Constant *>(A), IntTy, DL);
 988   else if (A->getType() != IntTy)
 989     A = ConstantFoldCastOperand(Instruction::BitCast, const_cast<Constant *>(A),
 990                                 IntTy, DL);
 991   if (isa<PointerType>(B->getType()))
 992     B = ConstantFoldCastOperand(Instruction::PtrToInt,
 993                                 const_cast<Constant *>(B), IntTy, DL);
 994   else if (B->getType() != IntTy)
 995     B = ConstantFoldCastOperand(Instruction::BitCast, const_cast<Constant *>(B),
 996                                 IntTy, DL);
 997
 998   return A == B;
 999 }
1000
1001 /// Create a new entry in the constant pool or return an existing one.
1002 /// User must specify the log2 of the minimum required alignment for the object.
1003 unsigned MachineConstantPool::getConstantPoolIndex(const Constant *C,
1004                                                    unsigned Alignment) {
1005   assert(Alignment && "Alignment must be specified!");
1006   if (Alignment > PoolAlignment) PoolAlignment = Alignment;
1007
1008   // Check to see if we already have this constant.
1009   //
1010   // FIXME, this could be made much more efficient for large constant pools.
1011   for (unsigned i = 0, e = Constants.size(); i != e; ++i)
1012     if (!Constants[i].isMachineConstantPoolEntry() &&
1013         CanShareConstantPoolEntry(Constants[i].Val.ConstVal, C, DL)) {
1014       if ((unsigned)Constants[i].getAlignment() < Alignment)
1015         Constants[i].Alignment = Alignment;
1016       return i;
1017     }
1018
1019   Constants.push_back(MachineConstantPoolEntry(C, Alignment));
1020   return Constants.size()-1;
1021 }
1022
1023 unsigned MachineConstantPool::getConstantPoolIndex(MachineConstantPoolValue *V,
1024                                                    unsigned Alignment) {
1025   assert(Alignment && "Alignment must be specified!");
1026   if (Alignment > PoolAlignment) PoolAlignment = Alignment;
1027
1028   // Check to see if we already have this constant.
1029   //
1030   // FIXME, this could be made much more efficient for large constant pools.
1031   int Idx = V->getExistingMachineCPValue(this, Alignment);
1032   if (Idx != -1) {
1033     MachineCPVsSharingEntries.insert(V);
1034     return (unsigned)Idx;
1035   }
1036
1037   Constants.push_back(MachineConstantPoolEntry(V, Alignment));
1038   return Constants.size()-1;
1039 }
1040
1041 void MachineConstantPool::print(raw_ostream &OS) const {
1042   if (Constants.empty()) return;
1043
1044   OS << "Constant Pool:\n";
1045   for (unsigned i = 0, e = Constants.size(); i != e; ++i) {
1046     OS << "  cp#" << i << ": ";
1047     if (Constants[i].isMachineConstantPoolEntry())
1048       Constants[i].Val.MachineCPVal->print(OS);
1049     else
1050       Constants[i].Val.ConstVal->printAsOperand(OS, /*PrintType=*/false);
1051     OS << ", align=" << Constants[i].getAlignment();
1052     OS << "\n";
1053   }
1054 }
1055
1056 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
1057 LLVM_DUMP_METHOD void MachineConstantPool::dump() const { print(dbgs()); }
1058 #endif