lib/CodeGen/MachineFunction.cpp

   1 //===- MachineFunction.cpp ------------------------------------------------===//
   2 //
   3 //                     The LLVM Compiler Infrastructure
   4 //
   5 // This file is distributed under the University of Illinois Open Source
   6 // License. See LICENSE.TXT for details.
   7 //
   8 //===----------------------------------------------------------------------===//
   9 //
  10 // Collect native machine code information for a function.  This allows
  11 // target-specific information about the generated code to be stored with each
  12 // function.
  13 //
  14 //===----------------------------------------------------------------------===//
  15
  16 #include "llvm/CodeGen/MachineFunction.h"
  17 #include "llvm/ADT/BitVector.h"
  18 #include "llvm/ADT/DenseMap.h"
  19 #include "llvm/ADT/DenseSet.h"
  20 #include "llvm/ADT/STLExtras.h"
  21 #include "llvm/ADT/SmallString.h"
  22 #include "llvm/ADT/SmallVector.h"
  23 #include "llvm/ADT/StringRef.h"
  24 #include "llvm/ADT/Twine.h"
  25 #include "llvm/Analysis/ConstantFolding.h"
  26 #include "llvm/Analysis/EHPersonalities.h"
  27 #include "llvm/CodeGen/MachineBasicBlock.h"
  28 #include "llvm/CodeGen/MachineConstantPool.h"
  29 #include "llvm/CodeGen/MachineFrameInfo.h"
  30 #include "llvm/CodeGen/MachineInstr.h"
  31 #include "llvm/CodeGen/MachineJumpTableInfo.h"
  32 #include "llvm/CodeGen/MachineMemOperand.h"
  33 #include "llvm/CodeGen/MachineModuleInfo.h"
  34 #include "llvm/CodeGen/MachineRegisterInfo.h"
  35 #include "llvm/CodeGen/PseudoSourceValue.h"
  36 #include "llvm/CodeGen/TargetFrameLowering.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/DerivedTypes.h"
  48 #include "llvm/IR/Function.h"
  49 #include "llvm/IR/GlobalValue.h"
  50 #include "llvm/IR/Instruction.h"
  51 #include "llvm/IR/Instructions.h"
  52 #include "llvm/IR/Metadata.h"
  53 #include "llvm/IR/Module.h"
  54 #include "llvm/IR/ModuleSlotTracker.h"
  55 #include "llvm/IR/Value.h"
  56 #include "llvm/MC/MCContext.h"
  57 #include "llvm/MC/MCSymbol.h"
  58 #include "llvm/MC/SectionKind.h"
  59 #include "llvm/Support/Casting.h"
  60 #include "llvm/Support/CommandLine.h"
  61 #include "llvm/Support/Compiler.h"
  62 #include "llvm/Support/DOTGraphTraits.h"
  63 #include "llvm/Support/Debug.h"
  64 #include "llvm/Support/ErrorHandling.h"
  65 #include "llvm/Support/GraphWriter.h"
  66 #include "llvm/Support/raw_ostream.h"
  67 #include "llvm/Target/TargetMachine.h"
  68 #include <algorithm>
  69 #include <cassert>
  70 #include <cstddef>
  71 #include <cstdint>
  72 #include <iterator>
  73 #include <string>
  74 #include <utility>
  75 #include <vector>
  76
  77 using namespace llvm;
  78
  79 #define DEBUG_TYPE "codegen"
  80
  81 static cl::opt<unsigned>
  82 AlignAllFunctions("align-all-functions",
  83                   cl::desc("Force the alignment of all functions."),
  84                   cl::init(0), cl::Hidden);
  85
  86 static const char *getPropertyName(MachineFunctionProperties::Property Prop) {
  87   using P = MachineFunctionProperties::Property;
  88
  89   switch(Prop) {
  90   case P::FailedISel: return "FailedISel";
  91   case P::IsSSA: return "IsSSA";
  92   case P::Legalized: return "Legalized";
  93   case P::NoPHIs: return "NoPHIs";
  94   case P::NoVRegs: return "NoVRegs";
  95   case P::RegBankSelected: return "RegBankSelected";
  96   case P::Selected: return "Selected";
  97   case P::TracksLiveness: return "TracksLiveness";
  98   }
  99   llvm_unreachable("Invalid machine function property");
 100 }
 101
 102 void MachineFunctionProperties::print(raw_ostream &OS) const {
 103   const char *Separator = "";
 104   for (BitVector::size_type I = 0; I < Properties.size(); ++I) {
 105     if (!Properties[I])
 106       continue;
 107     OS << Separator << getPropertyName(static_cast<Property>(I));
 108     Separator = ", ";
 109   }
 110 }
 111
 112 //===----------------------------------------------------------------------===//
 113 // MachineFunction implementation
 114 //===----------------------------------------------------------------------===//
 115
 116 // Out-of-line virtual method.
 117 MachineFunctionInfo::~MachineFunctionInfo() = default;
 118
 119 void ilist_alloc_traits<MachineBasicBlock>::deleteNode(MachineBasicBlock *MBB) {
 120   MBB->getParent()->DeleteMachineBasicBlock(MBB);
 121 }
 122
 123 static inline unsigned getFnStackAlignment(const TargetSubtargetInfo *STI,
 124                                            const Function &F) {
 125   if (F.hasFnAttribute(Attribute::StackAlignment))
 126     return F.getFnStackAlignment();
 127   return STI->getFrameLowering()->getStackAlignment();
 128 }
 129
 130 MachineFunction::MachineFunction(const Function &F, const TargetMachine &Target,
 131                                  const TargetSubtargetInfo &STI,
 132                                  unsigned FunctionNum, MachineModuleInfo &mmi)
 133     : F(F), Target(Target), STI(&STI), Ctx(mmi.getContext()), MMI(mmi) {
 134   FunctionNumber = FunctionNum;
 135   init();
 136 }
 137
 138 void MachineFunction::init() {
 139   // Assume the function starts in SSA form with correct liveness.
 140   Properties.set(MachineFunctionProperties::Property::IsSSA);
 141   Properties.set(MachineFunctionProperties::Property::TracksLiveness);
 142   if (STI->getRegisterInfo())
 143     RegInfo = new (Allocator) MachineRegisterInfo(this);
 144   else
 145     RegInfo = nullptr;
 146
 147   MFInfo = nullptr;
 148   // We can realign the stack if the target supports it and the user hasn't
 149   // explicitly asked us not to.
 150   bool CanRealignSP = STI->getFrameLowering()->isStackRealignable() &&
 151                       !F.hasFnAttribute("no-realign-stack");
 152   FrameInfo = new (Allocator) MachineFrameInfo(
 153       getFnStackAlignment(STI, F), /*StackRealignable=*/CanRealignSP,
 154       /*ForceRealign=*/CanRealignSP &&
 155           F.hasFnAttribute(Attribute::StackAlignment));
 156
 157   if (F.hasFnAttribute(Attribute::StackAlignment))
 158     FrameInfo->ensureMaxAlignment(F.getFnStackAlignment());
 159
 160   ConstantPool = new (Allocator) MachineConstantPool(getDataLayout());
 161   Alignment = STI->getTargetLowering()->getMinFunctionAlignment();
 162
 163   // FIXME: Shouldn't use pref alignment if explicit alignment is set on F.
 164   // FIXME: Use Function::optForSize().
 165   if (!F.hasFnAttribute(Attribute::OptimizeForSize))
 166     Alignment = std::max(Alignment,
 167                          STI->getTargetLowering()->getPrefFunctionAlignment());
 168
 169   if (AlignAllFunctions)
 170     Alignment = AlignAllFunctions;
 171
 172   JumpTableInfo = nullptr;
 173
 174   if (isFuncletEHPersonality(classifyEHPersonality(
 175           F.hasPersonalityFn() ? F.getPersonalityFn() : nullptr))) {
 176     WinEHInfo = new (Allocator) WinEHFuncInfo();
 177   }
 178
 179   if (isScopedEHPersonality(classifyEHPersonality(
 180           F.hasPersonalityFn() ? F.getPersonalityFn() : nullptr))) {
 181     WasmEHInfo = new (Allocator) WasmEHFuncInfo();
 182   }
 183
 184   assert(Target.isCompatibleDataLayout(getDataLayout()) &&
 185          "Can't create a MachineFunction using a Module with a "
 186          "Target-incompatible DataLayout attached\n");
 187
 188   PSVManager =
 189     llvm::make_unique<PseudoSourceValueManager>(*(getSubtarget().
 190                                                   getInstrInfo()));
 191 }
 192
 193 MachineFunction::~MachineFunction() {
 194   clear();
 195 }
 196
 197 void MachineFunction::clear() {
 198   Properties.reset();
 199   // Don't call destructors on MachineInstr and MachineOperand. All of their
 200   // memory comes from the BumpPtrAllocator which is about to be purged.
 201   //
 202   // Do call MachineBasicBlock destructors, it contains std::vectors.
 203   for (iterator I = begin(), E = end(); I != E; I = BasicBlocks.erase(I))
 204     I->Insts.clearAndLeakNodesUnsafely();
 205   MBBNumbering.clear();
 206
 207   InstructionRecycler.clear(Allocator);
 208   OperandRecycler.clear(Allocator);
 209   BasicBlockRecycler.clear(Allocator);
 210   CodeViewAnnotations.clear();
 211   VariableDbgInfos.clear();
 212   if (RegInfo) {
 213     RegInfo->~MachineRegisterInfo();
 214     Allocator.Deallocate(RegInfo);
 215   }
 216   if (MFInfo) {
 217     MFInfo->~MachineFunctionInfo();
 218     Allocator.Deallocate(MFInfo);
 219   }
 220
 221   FrameInfo->~MachineFrameInfo();
 222   Allocator.Deallocate(FrameInfo);
 223
 224   ConstantPool->~MachineConstantPool();
 225   Allocator.Deallocate(ConstantPool);
 226
 227   if (JumpTableInfo) {
 228     JumpTableInfo->~MachineJumpTableInfo();
 229     Allocator.Deallocate(JumpTableInfo);
 230   }
 231
 232   if (WinEHInfo) {
 233     WinEHInfo->~WinEHFuncInfo();
 234     Allocator.Deallocate(WinEHInfo);
 235   }
 236 }
 237
 238 const DataLayout &MachineFunction::getDataLayout() const {
 239   return F.getParent()->getDataLayout();
 240 }
 241
 242 /// Get the JumpTableInfo for this function.
 243 /// If it does not already exist, allocate one.
 244 MachineJumpTableInfo *MachineFunction::
 245 getOrCreateJumpTableInfo(unsigned EntryKind) {
 246   if (JumpTableInfo) return JumpTableInfo;
 247
 248   JumpTableInfo = new (Allocator)
 249     MachineJumpTableInfo((MachineJumpTableInfo::JTEntryKind)EntryKind);
 250   return JumpTableInfo;
 251 }
 252
 253 /// Should we be emitting segmented stack stuff for the function
 254 bool MachineFunction::shouldSplitStack() const {
 255   return getFunction().hasFnAttribute("split-stack");
 256 }
 257
 258 /// This discards all of the MachineBasicBlock numbers and recomputes them.
 259 /// This guarantees that the MBB numbers are sequential, dense, and match the
 260 /// ordering of the blocks within the function.  If a specific MachineBasicBlock
 261 /// is specified, only that block and those after it are renumbered.
 262 void MachineFunction::RenumberBlocks(MachineBasicBlock *MBB) {
 263   if (empty()) { MBBNumbering.clear(); return; }
 264   MachineFunction::iterator MBBI, E = end();
 265   if (MBB == nullptr)
 266     MBBI = begin();
 267   else
 268     MBBI = MBB->getIterator();
 269
 270   // Figure out the block number this should have.
 271   unsigned BlockNo = 0;
 272   if (MBBI != begin())
 273     BlockNo = std::prev(MBBI)->getNumber() + 1;
 274
 275   for (; MBBI != E; ++MBBI, ++BlockNo) {
 276     if (MBBI->getNumber() != (int)BlockNo) {
 277       // Remove use of the old number.
 278       if (MBBI->getNumber() != -1) {
 279         assert(MBBNumbering[MBBI->getNumber()] == &*MBBI &&
 280                "MBB number mismatch!");
 281         MBBNumbering[MBBI->getNumber()] = nullptr;
 282       }
 283
 284       // If BlockNo is already taken, set that block's number to -1.
 285       if (MBBNumbering[BlockNo])
 286         MBBNumbering[BlockNo]->setNumber(-1);
 287
 288       MBBNumbering[BlockNo] = &*MBBI;
 289       MBBI->setNumber(BlockNo);
 290     }
 291   }
 292
 293   // Okay, all the blocks are renumbered.  If we have compactified the block
 294   // numbering, shrink MBBNumbering now.
 295   assert(BlockNo <= MBBNumbering.size() && "Mismatch!");
 296   MBBNumbering.resize(BlockNo);
 297 }
 298
 299 /// Allocate a new MachineInstr. Use this instead of `new MachineInstr'.
 300 MachineInstr *MachineFunction::CreateMachineInstr(const MCInstrDesc &MCID,
 301                                                   const DebugLoc &DL,
 302                                                   bool NoImp) {
 303   return new (InstructionRecycler.Allocate<MachineInstr>(Allocator))
 304     MachineInstr(*this, MCID, DL, NoImp);
 305 }
 306
 307 /// Create a new MachineInstr which is a copy of the 'Orig' instruction,
 308 /// identical in all ways except the instruction has no parent, prev, or next.
 309 MachineInstr *
 310 MachineFunction::CloneMachineInstr(const MachineInstr *Orig) {
 311   return new (InstructionRecycler.Allocate<MachineInstr>(Allocator))
 312              MachineInstr(*this, *Orig);
 313 }
 314
 315 MachineInstr &MachineFunction::CloneMachineInstrBundle(MachineBasicBlock &MBB,
 316     MachineBasicBlock::iterator InsertBefore, const MachineInstr &Orig) {
 317   MachineInstr *FirstClone = nullptr;
 318   MachineBasicBlock::const_instr_iterator I = Orig.getIterator();
 319   while (true) {
 320     MachineInstr *Cloned = CloneMachineInstr(&*I);
 321     MBB.insert(InsertBefore, Cloned);
 322     if (FirstClone == nullptr) {
 323       FirstClone = Cloned;
 324     } else {
 325       Cloned->bundleWithPred();
 326     }
 327
 328     if (!I->isBundledWithSucc())
 329       break;
 330     ++I;
 331   }
 332   return *FirstClone;
 333 }
 334
 335 /// Delete the given MachineInstr.
 336 ///
 337 /// This function also serves as the MachineInstr destructor - the real
 338 /// ~MachineInstr() destructor must be empty.
 339 void
 340 MachineFunction::DeleteMachineInstr(MachineInstr *MI) {
 341   // Strip it for parts. The operand array and the MI object itself are
 342   // independently recyclable.
 343   if (MI->Operands)
 344     deallocateOperandArray(MI->CapOperands, MI->Operands);
 345   // Don't call ~MachineInstr() which must be trivial anyway because
 346   // ~MachineFunction drops whole lists of MachineInstrs wihout calling their
 347   // destructors.
 348   InstructionRecycler.Deallocate(Allocator, MI);
 349 }
 350
 351 /// Allocate a new MachineBasicBlock. Use this instead of
 352 /// `new MachineBasicBlock'.
 353 MachineBasicBlock *
 354 MachineFunction::CreateMachineBasicBlock(const BasicBlock *bb) {
 355   return new (BasicBlockRecycler.Allocate<MachineBasicBlock>(Allocator))
 356              MachineBasicBlock(*this, bb);
 357 }
 358
 359 /// Delete the given MachineBasicBlock.
 360 void
 361 MachineFunction::DeleteMachineBasicBlock(MachineBasicBlock *MBB) {
 362   assert(MBB->getParent() == this && "MBB parent mismatch!");
 363   MBB->~MachineBasicBlock();
 364   BasicBlockRecycler.Deallocate(Allocator, MBB);
 365 }
 366
 367 MachineMemOperand *MachineFunction::getMachineMemOperand(
 368     MachinePointerInfo PtrInfo, MachineMemOperand::Flags f, uint64_t s,
 369     unsigned base_alignment, const AAMDNodes &AAInfo, const MDNode *Ranges,
 370     SyncScope::ID SSID, AtomicOrdering Ordering,
 371     AtomicOrdering FailureOrdering) {
 372   return new (Allocator)
 373       MachineMemOperand(PtrInfo, f, s, base_alignment, AAInfo, Ranges,
 374                         SSID, Ordering, FailureOrdering);
 375 }
 376
 377 MachineMemOperand *
 378 MachineFunction::getMachineMemOperand(const MachineMemOperand *MMO,
 379                                       int64_t Offset, uint64_t Size) {
 380   if (MMO->getValue())
 381     return new (Allocator)
 382                MachineMemOperand(MachinePointerInfo(MMO->getValue(),
 383                                                     MMO->getOffset()+Offset),
 384                                  MMO->getFlags(), Size, MMO->getBaseAlignment(),
 385                                  AAMDNodes(), nullptr, MMO->getSyncScopeID(),
 386                                  MMO->getOrdering(), MMO->getFailureOrdering());
 387   return new (Allocator)
 388              MachineMemOperand(MachinePointerInfo(MMO->getPseudoValue(),
 389                                                   MMO->getOffset()+Offset),
 390                                MMO->getFlags(), Size, MMO->getBaseAlignment(),
 391                                AAMDNodes(), nullptr, MMO->getSyncScopeID(),
 392                                MMO->getOrdering(), MMO->getFailureOrdering());
 393 }
 394
 395 MachineMemOperand *
 396 MachineFunction::getMachineMemOperand(const MachineMemOperand *MMO,
 397                                       const AAMDNodes &AAInfo) {
 398   MachinePointerInfo MPI = MMO->getValue() ?
 399              MachinePointerInfo(MMO->getValue(), MMO->getOffset()) :
 400              MachinePointerInfo(MMO->getPseudoValue(), MMO->getOffset());
 401
 402   return new (Allocator)
 403              MachineMemOperand(MPI, MMO->getFlags(), MMO->getSize(),
 404                                MMO->getBaseAlignment(), AAInfo,
 405                                MMO->getRanges(), MMO->getSyncScopeID(),
 406                                MMO->getOrdering(), MMO->getFailureOrdering());
 407 }
 408
 409 MachineInstr::ExtraInfo *
 410 MachineFunction::createMIExtraInfo(ArrayRef<MachineMemOperand *> MMOs,
 411                                    MCSymbol *PreInstrSymbol,
 412                                    MCSymbol *PostInstrSymbol) {
 413   return MachineInstr::ExtraInfo::create(Allocator, MMOs, PreInstrSymbol,
 414                                          PostInstrSymbol);
 415 }
 416
 417 const char *MachineFunction::createExternalSymbolName(StringRef Name) {
 418   char *Dest = Allocator.Allocate<char>(Name.size() + 1);
 419   std::copy(Name.begin(), Name.end(), Dest);
 420   Dest[Name.size()] = 0;
 421   return Dest;
 422 }
 423
 424 uint32_t *MachineFunction::allocateRegMask() {
 425   unsigned NumRegs = getSubtarget().getRegisterInfo()->getNumRegs();
 426   unsigned Size = MachineOperand::getRegMaskSize(NumRegs);
 427   uint32_t *Mask = Allocator.Allocate<uint32_t>(Size);
 428   memset(Mask, 0, Size * sizeof(Mask[0]));
 429   return Mask;
 430 }
 431
 432 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
 433 LLVM_DUMP_METHOD void MachineFunction::dump() const {
 434   print(dbgs());
 435 }
 436 #endif
 437
 438 StringRef MachineFunction::getName() const {
 439   return getFunction().getName();
 440 }
 441
 442 void MachineFunction::print(raw_ostream &OS, const SlotIndexes *Indexes) const {
 443   OS << "# Machine code for function " << getName() << ": ";
 444   getProperties().print(OS);
 445   OS << '\n';
 446
 447   // Print Frame Information
 448   FrameInfo->print(*this, OS);
 449
 450   // Print JumpTable Information
 451   if (JumpTableInfo)
 452     JumpTableInfo->print(OS);
 453
 454   // Print Constant Pool
 455   ConstantPool->print(OS);
 456
 457   const TargetRegisterInfo *TRI = getSubtarget().getRegisterInfo();
 458
 459   if (RegInfo && !RegInfo->livein_empty()) {
 460     OS << "Function Live Ins: ";
 461     for (MachineRegisterInfo::livein_iterator
 462          I = RegInfo->livein_begin(), E = RegInfo->livein_end(); I != E; ++I) {
 463       OS << printReg(I->first, TRI);
 464       if (I->second)
 465         OS << " in " << printReg(I->second, TRI);
 466       if (std::next(I) != E)
 467         OS << ", ";
 468     }
 469     OS << '\n';
 470   }
 471
 472   ModuleSlotTracker MST(getFunction().getParent());
 473   MST.incorporateFunction(getFunction());
 474   for (const auto &BB : *this) {
 475     OS << '\n';
 476     // If we print the whole function, print it at its most verbose level.
 477     BB.print(OS, MST, Indexes, /*IsStandalone=*/true);
 478   }
 479
 480   OS << "\n# End machine code for function " << getName() << ".\n\n";
 481 }
 482
 483 namespace llvm {
 484
 485   template<>
 486   struct DOTGraphTraits<const MachineFunction*> : public DefaultDOTGraphTraits {
 487     DOTGraphTraits(bool isSimple = false) : DefaultDOTGraphTraits(isSimple) {}
 488
 489     static std::string getGraphName(const MachineFunction *F) {
 490       return ("CFG for '" + F->getName() + "' function").str();
 491     }
 492
 493     std::string getNodeLabel(const MachineBasicBlock *Node,
 494                              const MachineFunction *Graph) {
 495       std::string OutStr;
 496       {
 497         raw_string_ostream OSS(OutStr);
 498
 499         if (isSimple()) {
 500           OSS << printMBBReference(*Node);
 501           if (const BasicBlock *BB = Node->getBasicBlock())
 502             OSS << ": " << BB->getName();
 503         } else
 504           Node->print(OSS);
 505       }
 506
 507       if (OutStr[0] == '\n') OutStr.erase(OutStr.begin());
 508
 509       // Process string output to make it nicer...
 510       for (unsigned i = 0; i != OutStr.length(); ++i)
 511         if (OutStr[i] == '\n') {                            // Left justify
 512           OutStr[i] = '\\';
 513           OutStr.insert(OutStr.begin()+i+1, 'l');
 514         }
 515       return OutStr;
 516     }
 517   };
 518
 519 } // end namespace llvm
 520
 521 void MachineFunction::viewCFG() const
 522 {
 523 #ifndef NDEBUG
 524   ViewGraph(this, "mf" + getName());
 525 #else
 526   errs() << "MachineFunction::viewCFG is only available in debug builds on "
 527          << "systems with Graphviz or gv!\n";
 528 #endif // NDEBUG
 529 }
 530
 531 void MachineFunction::viewCFGOnly() const
 532 {
 533 #ifndef NDEBUG
 534   ViewGraph(this, "mf" + getName(), true);
 535 #else
 536   errs() << "MachineFunction::viewCFGOnly is only available in debug builds on "
 537          << "systems with Graphviz or gv!\n";
 538 #endif // NDEBUG
 539 }
 540
 541 /// Add the specified physical register as a live-in value and
 542 /// create a corresponding virtual register for it.
 543 unsigned MachineFunction::addLiveIn(unsigned PReg,
 544                                     const TargetRegisterClass *RC) {
 545   MachineRegisterInfo &MRI = getRegInfo();
 546   unsigned VReg = MRI.getLiveInVirtReg(PReg);
 547   if (VReg) {
 548     const TargetRegisterClass *VRegRC = MRI.getRegClass(VReg);
 549     (void)VRegRC;
 550     // A physical register can be added several times.
 551     // Between two calls, the register class of the related virtual register
 552     // may have been constrained to match some operation constraints.
 553     // In that case, check that the current register class includes the
 554     // physical register and is a sub class of the specified RC.
 555     assert((VRegRC == RC || (VRegRC->contains(PReg) &&
 556                              RC->hasSubClassEq(VRegRC))) &&
 557             "Register class mismatch!");
 558     return VReg;
 559   }
 560   VReg = MRI.createVirtualRegister(RC);
 561   MRI.addLiveIn(PReg, VReg);
 562   return VReg;
 563 }
 564
 565 /// Return the MCSymbol for the specified non-empty jump table.
 566 /// If isLinkerPrivate is specified, an 'l' label is returned, otherwise a
 567 /// normal 'L' label is returned.
 568 MCSymbol *MachineFunction::getJTISymbol(unsigned JTI, MCContext &Ctx,
 569                                         bool isLinkerPrivate) const {
 570   const DataLayout &DL = getDataLayout();
 571   assert(JumpTableInfo && "No jump tables");
 572   assert(JTI < JumpTableInfo->getJumpTables().size() && "Invalid JTI!");
 573
 574   StringRef Prefix = isLinkerPrivate ? DL.getLinkerPrivateGlobalPrefix()
 575                                      : DL.getPrivateGlobalPrefix();
 576   SmallString<60> Name;
 577   raw_svector_ostream(Name)
 578     << Prefix << "JTI" << getFunctionNumber() << '_' << JTI;
 579   return Ctx.getOrCreateSymbol(Name);
 580 }
 581
 582 /// Return a function-local symbol to represent the PIC base.
 583 MCSymbol *MachineFunction::getPICBaseSymbol() const {
 584   const DataLayout &DL = getDataLayout();
 585   return Ctx.getOrCreateSymbol(Twine(DL.getPrivateGlobalPrefix()) +
 586                                Twine(getFunctionNumber()) + "$pb");
 587 }
 588
 589 /// \name Exception Handling
 590 /// \{
 591
 592 LandingPadInfo &
 593 MachineFunction::getOrCreateLandingPadInfo(MachineBasicBlock *LandingPad) {
 594   unsigned N = LandingPads.size();
 595   for (unsigned i = 0; i < N; ++i) {
 596     LandingPadInfo &LP = LandingPads[i];
 597     if (LP.LandingPadBlock == LandingPad)
 598       return LP;
 599   }
 600
 601   LandingPads.push_back(LandingPadInfo(LandingPad));
 602   return LandingPads[N];
 603 }
 604
 605 void MachineFunction::addInvoke(MachineBasicBlock *LandingPad,
 606                                 MCSymbol *BeginLabel, MCSymbol *EndLabel) {
 607   LandingPadInfo &LP = getOrCreateLandingPadInfo(LandingPad);
 608   LP.BeginLabels.push_back(BeginLabel);
 609   LP.EndLabels.push_back(EndLabel);
 610 }
 611
 612 MCSymbol *MachineFunction::addLandingPad(MachineBasicBlock *LandingPad) {
 613   MCSymbol *LandingPadLabel = Ctx.createTempSymbol();
 614   LandingPadInfo &LP = getOrCreateLandingPadInfo(LandingPad);
 615   LP.LandingPadLabel = LandingPadLabel;
 616   return LandingPadLabel;
 617 }
 618
 619 void MachineFunction::addCatchTypeInfo(MachineBasicBlock *LandingPad,
 620                                        ArrayRef<const GlobalValue *> TyInfo) {
 621   LandingPadInfo &LP = getOrCreateLandingPadInfo(LandingPad);
 622   for (unsigned N = TyInfo.size(); N; --N)
 623     LP.TypeIds.push_back(getTypeIDFor(TyInfo[N - 1]));
 624 }
 625
 626 void MachineFunction::addFilterTypeInfo(MachineBasicBlock *LandingPad,
 627                                         ArrayRef<const GlobalValue *> TyInfo) {
 628   LandingPadInfo &LP = getOrCreateLandingPadInfo(LandingPad);
 629   std::vector<unsigned> IdsInFilter(TyInfo.size());
 630   for (unsigned I = 0, E = TyInfo.size(); I != E; ++I)
 631     IdsInFilter[I] = getTypeIDFor(TyInfo[I]);
 632   LP.TypeIds.push_back(getFilterIDFor(IdsInFilter));
 633 }
 634
 635 void MachineFunction::tidyLandingPads(DenseMap<MCSymbol*, uintptr_t> *LPMap) {
 636   for (unsigned i = 0; i != LandingPads.size(); ) {
 637     LandingPadInfo &LandingPad = LandingPads[i];
 638     if (LandingPad.LandingPadLabel &&
 639         !LandingPad.LandingPadLabel->isDefined() &&
 640         (!LPMap || (*LPMap)[LandingPad.LandingPadLabel] == 0))
 641       LandingPad.LandingPadLabel = nullptr;
 642
 643     // Special case: we *should* emit LPs with null LP MBB. This indicates
 644     // "nounwind" case.
 645     if (!LandingPad.LandingPadLabel && LandingPad.LandingPadBlock) {
 646       LandingPads.erase(LandingPads.begin() + i);
 647       continue;
 648     }
 649
 650     for (unsigned j = 0, e = LandingPads[i].BeginLabels.size(); j != e; ++j) {
 651       MCSymbol *BeginLabel = LandingPad.BeginLabels[j];
 652       MCSymbol *EndLabel = LandingPad.EndLabels[j];
 653       if ((BeginLabel->isDefined() ||
 654            (LPMap && (*LPMap)[BeginLabel] != 0)) &&
 655           (EndLabel->isDefined() ||
 656            (LPMap && (*LPMap)[EndLabel] != 0))) continue;
 657
 658       LandingPad.BeginLabels.erase(LandingPad.BeginLabels.begin() + j);
 659       LandingPad.EndLabels.erase(LandingPad.EndLabels.begin() + j);
 660       --j;
 661       --e;
 662     }
 663
 664     // Remove landing pads with no try-ranges.
 665     if (LandingPads[i].BeginLabels.empty()) {
 666       LandingPads.erase(LandingPads.begin() + i);
 667       continue;
 668     }
 669
 670     // If there is no landing pad, ensure that the list of typeids is empty.
 671     // If the only typeid is a cleanup, this is the same as having no typeids.
 672     if (!LandingPad.LandingPadBlock ||
 673         (LandingPad.TypeIds.size() == 1 && !LandingPad.TypeIds[0]))
 674       LandingPad.TypeIds.clear();
 675     ++i;
 676   }
 677 }
 678
 679 void MachineFunction::addCleanup(MachineBasicBlock *LandingPad) {
 680   LandingPadInfo &LP = getOrCreateLandingPadInfo(LandingPad);
 681   LP.TypeIds.push_back(0);
 682 }
 683
 684 void MachineFunction::addSEHCatchHandler(MachineBasicBlock *LandingPad,
 685                                          const Function *Filter,
 686                                          const BlockAddress *RecoverBA) {
 687   LandingPadInfo &LP = getOrCreateLandingPadInfo(LandingPad);
 688   SEHHandler Handler;
 689   Handler.FilterOrFinally = Filter;
 690   Handler.RecoverBA = RecoverBA;
 691   LP.SEHHandlers.push_back(Handler);
 692 }
 693
 694 void MachineFunction::addSEHCleanupHandler(MachineBasicBlock *LandingPad,
 695                                            const Function *Cleanup) {
 696   LandingPadInfo &LP = getOrCreateLandingPadInfo(LandingPad);
 697   SEHHandler Handler;
 698   Handler.FilterOrFinally = Cleanup;
 699   Handler.RecoverBA = nullptr;
 700   LP.SEHHandlers.push_back(Handler);
 701 }
 702
 703 void MachineFunction::setCallSiteLandingPad(MCSymbol *Sym,
 704                                             ArrayRef<unsigned> Sites) {
 705   LPadToCallSiteMap[Sym].append(Sites.begin(), Sites.end());
 706 }
 707
 708 unsigned MachineFunction::getTypeIDFor(const GlobalValue *TI) {
 709   for (unsigned i = 0, N = TypeInfos.size(); i != N; ++i)
 710     if (TypeInfos[i] == TI) return i + 1;
 711
 712   TypeInfos.push_back(TI);
 713   return TypeInfos.size();
 714 }
 715
 716 int MachineFunction::getFilterIDFor(std::vector<unsigned> &TyIds) {
 717   // If the new filter coincides with the tail of an existing filter, then
 718   // re-use the existing filter.  Folding filters more than this requires
 719   // re-ordering filters and/or their elements - probably not worth it.
 720   for (std::vector<unsigned>::iterator I = FilterEnds.begin(),
 721        E = FilterEnds.end(); I != E; ++I) {
 722     unsigned i = *I, j = TyIds.size();
 723
 724     while (i && j)
 725       if (FilterIds[--i] != TyIds[--j])
 726         goto try_next;
 727
 728     if (!j)
 729       // The new filter coincides with range [i, end) of the existing filter.
 730       return -(1 + i);
 731
 732 try_next:;
 733   }
 734
 735   // Add the new filter.
 736   int FilterID = -(1 + FilterIds.size());
 737   FilterIds.reserve(FilterIds.size() + TyIds.size() + 1);
 738   FilterIds.insert(FilterIds.end(), TyIds.begin(), TyIds.end());
 739   FilterEnds.push_back(FilterIds.size());
 740   FilterIds.push_back(0); // terminator
 741   return FilterID;
 742 }
 743
 744 void llvm::addLandingPadInfo(const LandingPadInst &I, MachineBasicBlock &MBB) {
 745   MachineFunction &MF = *MBB.getParent();
 746   if (const auto *PF = dyn_cast<Function>(
 747           I.getParent()->getParent()->getPersonalityFn()->stripPointerCasts()))
 748     MF.getMMI().addPersonality(PF);
 749
 750   if (I.isCleanup())
 751     MF.addCleanup(&MBB);
 752
 753   // FIXME: New EH - Add the clauses in reverse order. This isn't 100% correct,
 754   //        but we need to do it this way because of how the DWARF EH emitter
 755   //        processes the clauses.
 756   for (unsigned i = I.getNumClauses(); i != 0; --i) {
 757     Value *Val = I.getClause(i - 1);
 758     if (I.isCatch(i - 1)) {
 759       MF.addCatchTypeInfo(&MBB,
 760                           dyn_cast<GlobalValue>(Val->stripPointerCasts()));
 761     } else {
 762       // Add filters in a list.
 763       Constant *CVal = cast<Constant>(Val);
 764       SmallVector<const GlobalValue *, 4> FilterList;
 765       for (User::op_iterator II = CVal->op_begin(), IE = CVal->op_end();
 766            II != IE; ++II)
 767         FilterList.push_back(cast<GlobalValue>((*II)->stripPointerCasts()));
 768
 769       MF.addFilterTypeInfo(&MBB, FilterList);
 770     }
 771   }
 772 }
 773
 774 /// \}
 775
 776 //===----------------------------------------------------------------------===//
 777 //  MachineJumpTableInfo implementation
 778 //===----------------------------------------------------------------------===//
 779
 780 /// Return the size of each entry in the jump table.
 781 unsigned MachineJumpTableInfo::getEntrySize(const DataLayout &TD) const {
 782   // The size of a jump table entry is 4 bytes unless the entry is just the
 783   // address of a block, in which case it is the pointer size.
 784   switch (getEntryKind()) {
 785   case MachineJumpTableInfo::EK_BlockAddress:
 786     return TD.getPointerSize();
 787   case MachineJumpTableInfo::EK_GPRel64BlockAddress:
 788     return 8;
 789   case MachineJumpTableInfo::EK_GPRel32BlockAddress:
 790   case MachineJumpTableInfo::EK_LabelDifference32:
 791   case MachineJumpTableInfo::EK_Custom32:
 792     return 4;
 793   case MachineJumpTableInfo::EK_Inline:
 794     return 0;
 795   }
 796   llvm_unreachable("Unknown jump table encoding!");
 797 }
 798
 799 /// Return the alignment of each entry in the jump table.
 800 unsigned MachineJumpTableInfo::getEntryAlignment(const DataLayout &TD) const {
 801   // The alignment of a jump table entry is the alignment of int32 unless the
 802   // entry is just the address of a block, in which case it is the pointer
 803   // alignment.
 804   switch (getEntryKind()) {
 805   case MachineJumpTableInfo::EK_BlockAddress:
 806     return TD.getPointerABIAlignment(0);
 807   case MachineJumpTableInfo::EK_GPRel64BlockAddress:
 808     return TD.getABIIntegerTypeAlignment(64);
 809   case MachineJumpTableInfo::EK_GPRel32BlockAddress:
 810   case MachineJumpTableInfo::EK_LabelDifference32:
 811   case MachineJumpTableInfo::EK_Custom32:
 812     return TD.getABIIntegerTypeAlignment(32);
 813   case MachineJumpTableInfo::EK_Inline:
 814     return 1;
 815   }
 816   llvm_unreachable("Unknown jump table encoding!");
 817 }
 818
 819 /// Create a new jump table entry in the jump table info.
 820 unsigned MachineJumpTableInfo::createJumpTableIndex(
 821                                const std::vector<MachineBasicBlock*> &DestBBs) {
 822   assert(!DestBBs.empty() && "Cannot create an empty jump table!");
 823   JumpTables.push_back(MachineJumpTableEntry(DestBBs));
 824   return JumpTables.size()-1;
 825 }
 826
 827 /// If Old is the target of any jump tables, update the jump tables to branch
 828 /// to New instead.
 829 bool MachineJumpTableInfo::ReplaceMBBInJumpTables(MachineBasicBlock *Old,
 830                                                   MachineBasicBlock *New) {
 831   assert(Old != New && "Not making a change?");
 832   bool MadeChange = false;
 833   for (size_t i = 0, e = JumpTables.size(); i != e; ++i)
 834     ReplaceMBBInJumpTable(i, Old, New);
 835   return MadeChange;
 836 }
 837
 838 /// If Old is a target of the jump tables, update the jump table to branch to
 839 /// New instead.
 840 bool MachineJumpTableInfo::ReplaceMBBInJumpTable(unsigned Idx,
 841                                                  MachineBasicBlock *Old,
 842                                                  MachineBasicBlock *New) {
 843   assert(Old != New && "Not making a change?");
 844   bool MadeChange = false;
 845   MachineJumpTableEntry &JTE = JumpTables[Idx];
 846   for (size_t j = 0, e = JTE.MBBs.size(); j != e; ++j)
 847     if (JTE.MBBs[j] == Old) {
 848       JTE.MBBs[j] = New;
 849       MadeChange = true;
 850     }
 851   return MadeChange;
 852 }
 853
 854 void MachineJumpTableInfo::print(raw_ostream &OS) const {
 855   if (JumpTables.empty()) return;
 856
 857   OS << "Jump Tables:\n";
 858
 859   for (unsigned i = 0, e = JumpTables.size(); i != e; ++i) {
 860     OS << printJumpTableEntryReference(i) << ": ";
 861     for (unsigned j = 0, f = JumpTables[i].MBBs.size(); j != f; ++j)
 862       OS << ' ' << printMBBReference(*JumpTables[i].MBBs[j]);
 863   }
 864
 865   OS << '\n';
 866 }
 867
 868 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
 869 LLVM_DUMP_METHOD void MachineJumpTableInfo::dump() const { print(dbgs()); }
 870 #endif
 871
 872 Printable llvm::printJumpTableEntryReference(unsigned Idx) {
 873   return Printable([Idx](raw_ostream &OS) { OS << "%jump-table." << Idx; });
 874 }
 875
 876 //===----------------------------------------------------------------------===//
 877 //  MachineConstantPool implementation
 878 //===----------------------------------------------------------------------===//
 879
 880 void MachineConstantPoolValue::anchor() {}
 881
 882 Type *MachineConstantPoolEntry::getType() const {
 883   if (isMachineConstantPoolEntry())
 884     return Val.MachineCPVal->getType();
 885   return Val.ConstVal->getType();
 886 }
 887
 888 bool MachineConstantPoolEntry::needsRelocation() const {
 889   if (isMachineConstantPoolEntry())
 890     return true;
 891   return Val.ConstVal->needsRelocation();
 892 }
 893
 894 SectionKind
 895 MachineConstantPoolEntry::getSectionKind(const DataLayout *DL) const {
 896   if (needsRelocation())
 897     return SectionKind::getReadOnlyWithRel();
 898   switch (DL->getTypeAllocSize(getType())) {
 899   case 4:
 900     return SectionKind::getMergeableConst4();
 901   case 8:
 902     return SectionKind::getMergeableConst8();
 903   case 16:
 904     return SectionKind::getMergeableConst16();
 905   case 32:
 906     return SectionKind::getMergeableConst32();
 907   default:
 908     return SectionKind::getReadOnly();
 909   }
 910 }
 911
 912 MachineConstantPool::~MachineConstantPool() {
 913   // A constant may be a member of both Constants and MachineCPVsSharingEntries,
 914   // so keep track of which we've deleted to avoid double deletions.
 915   DenseSet<MachineConstantPoolValue*> Deleted;
 916   for (unsigned i = 0, e = Constants.size(); i != e; ++i)
 917     if (Constants[i].isMachineConstantPoolEntry()) {
 918       Deleted.insert(Constants[i].Val.MachineCPVal);
 919       delete Constants[i].Val.MachineCPVal;
 920     }
 921   for (DenseSet<MachineConstantPoolValue*>::iterator I =
 922        MachineCPVsSharingEntries.begin(), E = MachineCPVsSharingEntries.end();
 923        I != E; ++I) {
 924     if (Deleted.count(*I) == 0)
 925       delete *I;
 926   }
 927 }
 928
 929 /// Test whether the given two constants can be allocated the same constant pool
 930 /// entry.
 931 static bool CanShareConstantPoolEntry(const Constant *A, const Constant *B,
 932                                       const DataLayout &DL) {
 933   // Handle the trivial case quickly.
 934   if (A == B) return true;
 935
 936   // If they have the same type but weren't the same constant, quickly
 937   // reject them.
 938   if (A->getType() == B->getType()) return false;
 939
 940   // We can't handle structs or arrays.
 941   if (isa<StructType>(A->getType()) || isa<ArrayType>(A->getType()) ||
 942       isa<StructType>(B->getType()) || isa<ArrayType>(B->getType()))
 943     return false;
 944
 945   // For now, only support constants with the same size.
 946   uint64_t StoreSize = DL.getTypeStoreSize(A->getType());
 947   if (StoreSize != DL.getTypeStoreSize(B->getType()) || StoreSize > 128)
 948     return false;
 949
 950   Type *IntTy = IntegerType::get(A->getContext(), StoreSize*8);
 951
 952   // Try constant folding a bitcast of both instructions to an integer.  If we
 953   // get two identical ConstantInt's, then we are good to share them.  We use
 954   // the constant folding APIs to do this so that we get the benefit of
 955   // DataLayout.
 956   if (isa<PointerType>(A->getType()))
 957     A = ConstantFoldCastOperand(Instruction::PtrToInt,
 958                                 const_cast<Constant *>(A), IntTy, DL);
 959   else if (A->getType() != IntTy)
 960     A = ConstantFoldCastOperand(Instruction::BitCast, const_cast<Constant *>(A),
 961                                 IntTy, DL);
 962   if (isa<PointerType>(B->getType()))
 963     B = ConstantFoldCastOperand(Instruction::PtrToInt,
 964                                 const_cast<Constant *>(B), IntTy, DL);
 965   else if (B->getType() != IntTy)
 966     B = ConstantFoldCastOperand(Instruction::BitCast, const_cast<Constant *>(B),
 967                                 IntTy, DL);
 968
 969   return A == B;
 970 }
 971
 972 /// Create a new entry in the constant pool or return an existing one.
 973 /// User must specify the log2 of the minimum required alignment for the object.
 974 unsigned MachineConstantPool::getConstantPoolIndex(const Constant *C,
 975                                                    unsigned Alignment) {
 976   assert(Alignment && "Alignment must be specified!");
 977   if (Alignment > PoolAlignment) PoolAlignment = Alignment;
 978
 979   // Check to see if we already have this constant.
 980   //
 981   // FIXME, this could be made much more efficient for large constant pools.
 982   for (unsigned i = 0, e = Constants.size(); i != e; ++i)
 983     if (!Constants[i].isMachineConstantPoolEntry() &&
 984         CanShareConstantPoolEntry(Constants[i].Val.ConstVal, C, DL)) {
 985       if ((unsigned)Constants[i].getAlignment() < Alignment)
 986         Constants[i].Alignment = Alignment;
 987       return i;
 988     }
 989
 990   Constants.push_back(MachineConstantPoolEntry(C, Alignment));
 991   return Constants.size()-1;
 992 }
 993
 994 unsigned MachineConstantPool::getConstantPoolIndex(MachineConstantPoolValue *V,
 995                                                    unsigned Alignment) {
 996   assert(Alignment && "Alignment must be specified!");
 997   if (Alignment > PoolAlignment) PoolAlignment = Alignment;
 998
 999   // Check to see if we already have this constant.
1000   //
1001   // FIXME, this could be made much more efficient for large constant pools.
1002   int Idx = V->getExistingMachineCPValue(this, Alignment);
1003   if (Idx != -1) {
1004     MachineCPVsSharingEntries.insert(V);
1005     return (unsigned)Idx;
1006   }
1007
1008   Constants.push_back(MachineConstantPoolEntry(V, Alignment));
1009   return Constants.size()-1;
1010 }
1011
1012 void MachineConstantPool::print(raw_ostream &OS) const {
1013   if (Constants.empty()) return;
1014
1015   OS << "Constant Pool:\n";
1016   for (unsigned i = 0, e = Constants.size(); i != e; ++i) {
1017     OS << "  cp#" << i << ": ";
1018     if (Constants[i].isMachineConstantPoolEntry())
1019       Constants[i].Val.MachineCPVal->print(OS);
1020     else
1021       Constants[i].Val.ConstVal->printAsOperand(OS, /*PrintType=*/false);
1022     OS << ", align=" << Constants[i].getAlignment();
1023     OS << "\n";
1024   }
1025 }
1026
1027 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
1028 LLVM_DUMP_METHOD void MachineConstantPool::dump() const { print(dbgs()); }
1029 #endif