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/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/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 <type_traits>
  74 #include <utility>
  75 #include <vector>
  76
  77 #include "LiveDebugValues/LiveDebugValues.h"
  78
  79 using namespace llvm;
  80
  81 #define DEBUG_TYPE "codegen"
  82
  83 static cl::opt<unsigned> AlignAllFunctions(
  84     "align-all-functions",
  85     cl::desc("Force the alignment of all functions in log2 format (e.g. 4 "
  86              "means align on 16B boundaries)."),
  87     cl::init(0), cl::Hidden);
  88
  89 static const char *getPropertyName(MachineFunctionProperties::Property Prop) {
  90   using P = MachineFunctionProperties::Property;
  91
  92   // clang-format off
  93   switch(Prop) {
  94   case P::FailedISel: return "FailedISel";
  95   case P::IsSSA: return "IsSSA";
  96   case P::Legalized: return "Legalized";
  97   case P::NoPHIs: return "NoPHIs";
  98   case P::NoVRegs: return "NoVRegs";
  99   case P::RegBankSelected: return "RegBankSelected";
 100   case P::Selected: return "Selected";
 101   case P::TracksLiveness: return "TracksLiveness";
 102   case P::TiedOpsRewritten: return "TiedOpsRewritten";
 103   case P::FailsVerification: return "FailsVerification";
 104   case P::TracksDebugUserValues: return "TracksDebugUserValues";
 105   }
 106   // clang-format on
 107   llvm_unreachable("Invalid machine function property");
 108 }
 109
 110 void setUnsafeStackSize(const Function &F, MachineFrameInfo &FrameInfo) {
 111   if (!F.hasFnAttribute(Attribute::SafeStack))
 112     return;
 113
 114   auto *Existing =
 115       dyn_cast_or_null<MDTuple>(F.getMetadata(LLVMContext::MD_annotation));
 116
 117   if (!Existing || Existing->getNumOperands() != 2)
 118     return;
 119
 120   auto *MetadataName = "unsafe-stack-size";
 121   if (auto &N = Existing->getOperand(0)) {
 122     if (cast<MDString>(N.get())->getString() == MetadataName) {
 123       if (auto &Op = Existing->getOperand(1)) {
 124         auto Val = mdconst::extract<ConstantInt>(Op)->getZExtValue();
 125         FrameInfo.setUnsafeStackSize(Val);
 126       }
 127     }
 128   }
 129 }
 130
 131 // Pin the vtable to this file.
 132 void MachineFunction::Delegate::anchor() {}
 133
 134 void MachineFunctionProperties::print(raw_ostream &OS) const {
 135   const char *Separator = "";
 136   for (BitVector::size_type I = 0; I < Properties.size(); ++I) {
 137     if (!Properties[I])
 138       continue;
 139     OS << Separator << getPropertyName(static_cast<Property>(I));
 140     Separator = ", ";
 141   }
 142 }
 143
 144 //===----------------------------------------------------------------------===//
 145 // MachineFunction implementation
 146 //===----------------------------------------------------------------------===//
 147
 148 // Out-of-line virtual method.
 149 MachineFunctionInfo::~MachineFunctionInfo() = default;
 150
 151 void ilist_alloc_traits<MachineBasicBlock>::deleteNode(MachineBasicBlock *MBB) {
 152   MBB->getParent()->deleteMachineBasicBlock(MBB);
 153 }
 154
 155 static inline Align getFnStackAlignment(const TargetSubtargetInfo *STI,
 156                                            const Function &F) {
 157   if (auto MA = F.getFnStackAlign())
 158     return *MA;
 159   return STI->getFrameLowering()->getStackAlign();
 160 }
 161
 162 MachineFunction::MachineFunction(Function &F, const LLVMTargetMachine &Target,
 163                                  const TargetSubtargetInfo &STI,
 164                                  unsigned FunctionNum, MachineModuleInfo &mmi)
 165     : F(F), Target(Target), STI(&STI), Ctx(mmi.getContext()), MMI(mmi) {
 166   FunctionNumber = FunctionNum;
 167   init();
 168 }
 169
 170 void MachineFunction::handleInsertion(MachineInstr &MI) {
 171   if (TheDelegate)
 172     TheDelegate->MF_HandleInsertion(MI);
 173 }
 174
 175 void MachineFunction::handleRemoval(MachineInstr &MI) {
 176   if (TheDelegate)
 177     TheDelegate->MF_HandleRemoval(MI);
 178 }
 179
 180 void MachineFunction::init() {
 181   // Assume the function starts in SSA form with correct liveness.
 182   Properties.set(MachineFunctionProperties::Property::IsSSA);
 183   Properties.set(MachineFunctionProperties::Property::TracksLiveness);
 184   if (STI->getRegisterInfo())
 185     RegInfo = new (Allocator) MachineRegisterInfo(this);
 186   else
 187     RegInfo = nullptr;
 188
 189   MFInfo = nullptr;
 190   // We can realign the stack if the target supports it and the user hasn't
 191   // explicitly asked us not to.
 192   bool CanRealignSP = STI->getFrameLowering()->isStackRealignable() &&
 193                       !F.hasFnAttribute("no-realign-stack");
 194   FrameInfo = new (Allocator) MachineFrameInfo(
 195       getFnStackAlignment(STI, F), /*StackRealignable=*/CanRealignSP,
 196       /*ForcedRealign=*/CanRealignSP &&
 197           F.hasFnAttribute(Attribute::StackAlignment));
 198
 199   setUnsafeStackSize(F, *FrameInfo);
 200
 201   if (F.hasFnAttribute(Attribute::StackAlignment))
 202     FrameInfo->ensureMaxAlignment(*F.getFnStackAlign());
 203
 204   ConstantPool = new (Allocator) MachineConstantPool(getDataLayout());
 205   Alignment = STI->getTargetLowering()->getMinFunctionAlignment();
 206
 207   // FIXME: Shouldn't use pref alignment if explicit alignment is set on F.
 208   // FIXME: Use Function::hasOptSize().
 209   if (!F.hasFnAttribute(Attribute::OptimizeForSize))
 210     Alignment = std::max(Alignment,
 211                          STI->getTargetLowering()->getPrefFunctionAlignment());
 212
 213   if (AlignAllFunctions)
 214     Alignment = Align(1ULL << AlignAllFunctions);
 215
 216   JumpTableInfo = nullptr;
 217
 218   if (isFuncletEHPersonality(classifyEHPersonality(
 219           F.hasPersonalityFn() ? F.getPersonalityFn() : nullptr))) {
 220     WinEHInfo = new (Allocator) WinEHFuncInfo();
 221   }
 222
 223   if (isScopedEHPersonality(classifyEHPersonality(
 224           F.hasPersonalityFn() ? F.getPersonalityFn() : nullptr))) {
 225     WasmEHInfo = new (Allocator) WasmEHFuncInfo();
 226   }
 227
 228   assert(Target.isCompatibleDataLayout(getDataLayout()) &&
 229          "Can't create a MachineFunction using a Module with a "
 230          "Target-incompatible DataLayout attached\n");
 231
 232   PSVManager = std::make_unique<PseudoSourceValueManager>(getTarget());
 233 }
 234
 235 MachineFunction::~MachineFunction() {
 236   clear();
 237 }
 238
 239 void MachineFunction::clear() {
 240   Properties.reset();
 241   // Don't call destructors on MachineInstr and MachineOperand. All of their
 242   // memory comes from the BumpPtrAllocator which is about to be purged.
 243   //
 244   // Do call MachineBasicBlock destructors, it contains std::vectors.
 245   for (iterator I = begin(), E = end(); I != E; I = BasicBlocks.erase(I))
 246     I->Insts.clearAndLeakNodesUnsafely();
 247   MBBNumbering.clear();
 248
 249   InstructionRecycler.clear(Allocator);
 250   OperandRecycler.clear(Allocator);
 251   BasicBlockRecycler.clear(Allocator);
 252   CodeViewAnnotations.clear();
 253   VariableDbgInfos.clear();
 254   if (RegInfo) {
 255     RegInfo->~MachineRegisterInfo();
 256     Allocator.Deallocate(RegInfo);
 257   }
 258   if (MFInfo) {
 259     MFInfo->~MachineFunctionInfo();
 260     Allocator.Deallocate(MFInfo);
 261   }
 262
 263   FrameInfo->~MachineFrameInfo();
 264   Allocator.Deallocate(FrameInfo);
 265
 266   ConstantPool->~MachineConstantPool();
 267   Allocator.Deallocate(ConstantPool);
 268
 269   if (JumpTableInfo) {
 270     JumpTableInfo->~MachineJumpTableInfo();
 271     Allocator.Deallocate(JumpTableInfo);
 272   }
 273
 274   if (WinEHInfo) {
 275     WinEHInfo->~WinEHFuncInfo();
 276     Allocator.Deallocate(WinEHInfo);
 277   }
 278
 279   if (WasmEHInfo) {
 280     WasmEHInfo->~WasmEHFuncInfo();
 281     Allocator.Deallocate(WasmEHInfo);
 282   }
 283 }
 284
 285 const DataLayout &MachineFunction::getDataLayout() const {
 286   return F.getParent()->getDataLayout();
 287 }
 288
 289 /// Get the JumpTableInfo for this function.
 290 /// If it does not already exist, allocate one.
 291 MachineJumpTableInfo *MachineFunction::
 292 getOrCreateJumpTableInfo(unsigned EntryKind) {
 293   if (JumpTableInfo) return JumpTableInfo;
 294
 295   JumpTableInfo = new (Allocator)
 296     MachineJumpTableInfo((MachineJumpTableInfo::JTEntryKind)EntryKind);
 297   return JumpTableInfo;
 298 }
 299
 300 DenormalMode MachineFunction::getDenormalMode(const fltSemantics &FPType) const {
 301   return F.getDenormalMode(FPType);
 302 }
 303
 304 /// Should we be emitting segmented stack stuff for the function
 305 bool MachineFunction::shouldSplitStack() const {
 306   return getFunction().hasFnAttribute("split-stack");
 307 }
 308
 309 [[nodiscard]] unsigned
 310 MachineFunction::addFrameInst(const MCCFIInstruction &Inst) {
 311   FrameInstructions.push_back(Inst);
 312   return FrameInstructions.size() - 1;
 313 }
 314
 315 /// This discards all of the MachineBasicBlock numbers and recomputes them.
 316 /// This guarantees that the MBB numbers are sequential, dense, and match the
 317 /// ordering of the blocks within the function.  If a specific MachineBasicBlock
 318 /// is specified, only that block and those after it are renumbered.
 319 void MachineFunction::RenumberBlocks(MachineBasicBlock *MBB) {
 320   if (empty()) { MBBNumbering.clear(); return; }
 321   MachineFunction::iterator MBBI, E = end();
 322   if (MBB == nullptr)
 323     MBBI = begin();
 324   else
 325     MBBI = MBB->getIterator();
 326
 327   // Figure out the block number this should have.
 328   unsigned BlockNo = 0;
 329   if (MBBI != begin())
 330     BlockNo = std::prev(MBBI)->getNumber() + 1;
 331
 332   for (; MBBI != E; ++MBBI, ++BlockNo) {
 333     if (MBBI->getNumber() != (int)BlockNo) {
 334       // Remove use of the old number.
 335       if (MBBI->getNumber() != -1) {
 336         assert(MBBNumbering[MBBI->getNumber()] == &*MBBI &&
 337                "MBB number mismatch!");
 338         MBBNumbering[MBBI->getNumber()] = nullptr;
 339       }
 340
 341       // If BlockNo is already taken, set that block's number to -1.
 342       if (MBBNumbering[BlockNo])
 343         MBBNumbering[BlockNo]->setNumber(-1);
 344
 345       MBBNumbering[BlockNo] = &*MBBI;
 346       MBBI->setNumber(BlockNo);
 347     }
 348   }
 349
 350   // Okay, all the blocks are renumbered.  If we have compactified the block
 351   // numbering, shrink MBBNumbering now.
 352   assert(BlockNo <= MBBNumbering.size() && "Mismatch!");
 353   MBBNumbering.resize(BlockNo);
 354 }
 355
 356 /// This method iterates over the basic blocks and assigns their IsBeginSection
 357 /// and IsEndSection fields. This must be called after MBB layout is finalized
 358 /// and the SectionID's are assigned to MBBs.
 359 void MachineFunction::assignBeginEndSections() {
 360   front().setIsBeginSection();
 361   auto CurrentSectionID = front().getSectionID();
 362   for (auto MBBI = std::next(begin()), E = end(); MBBI != E; ++MBBI) {
 363     if (MBBI->getSectionID() == CurrentSectionID)
 364       continue;
 365     MBBI->setIsBeginSection();
 366     std::prev(MBBI)->setIsEndSection();
 367     CurrentSectionID = MBBI->getSectionID();
 368   }
 369   back().setIsEndSection();
 370 }
 371
 372 /// Allocate a new MachineInstr. Use this instead of `new MachineInstr'.
 373 MachineInstr *MachineFunction::CreateMachineInstr(const MCInstrDesc &MCID,
 374                                                   DebugLoc DL,
 375                                                   bool NoImplicit) {
 376   return new (InstructionRecycler.Allocate<MachineInstr>(Allocator))
 377       MachineInstr(*this, MCID, std::move(DL), NoImplicit);
 378 }
 379
 380 /// Create a new MachineInstr which is a copy of the 'Orig' instruction,
 381 /// identical in all ways except the instruction has no parent, prev, or next.
 382 MachineInstr *
 383 MachineFunction::CloneMachineInstr(const MachineInstr *Orig) {
 384   return new (InstructionRecycler.Allocate<MachineInstr>(Allocator))
 385              MachineInstr(*this, *Orig);
 386 }
 387
 388 MachineInstr &MachineFunction::cloneMachineInstrBundle(
 389     MachineBasicBlock &MBB, MachineBasicBlock::iterator InsertBefore,
 390     const MachineInstr &Orig) {
 391   MachineInstr *FirstClone = nullptr;
 392   MachineBasicBlock::const_instr_iterator I = Orig.getIterator();
 393   while (true) {
 394     MachineInstr *Cloned = CloneMachineInstr(&*I);
 395     MBB.insert(InsertBefore, Cloned);
 396     if (FirstClone == nullptr) {
 397       FirstClone = Cloned;
 398     } else {
 399       Cloned->bundleWithPred();
 400     }
 401
 402     if (!I->isBundledWithSucc())
 403       break;
 404     ++I;
 405   }
 406   // Copy over call site info to the cloned instruction if needed. If Orig is in
 407   // a bundle, copyCallSiteInfo takes care of finding the call instruction in
 408   // the bundle.
 409   if (Orig.shouldUpdateCallSiteInfo())
 410     copyCallSiteInfo(&Orig, FirstClone);
 411   return *FirstClone;
 412 }
 413
 414 /// Delete the given MachineInstr.
 415 ///
 416 /// This function also serves as the MachineInstr destructor - the real
 417 /// ~MachineInstr() destructor must be empty.
 418 void MachineFunction::deleteMachineInstr(MachineInstr *MI) {
 419   // Verify that a call site info is at valid state. This assertion should
 420   // be triggered during the implementation of support for the
 421   // call site info of a new architecture. If the assertion is triggered,
 422   // back trace will tell where to insert a call to updateCallSiteInfo().
 423   assert((!MI->isCandidateForCallSiteEntry() ||
 424           CallSitesInfo.find(MI) == CallSitesInfo.end()) &&
 425          "Call site info was not updated!");
 426   // Strip it for parts. The operand array and the MI object itself are
 427   // independently recyclable.
 428   if (MI->Operands)
 429     deallocateOperandArray(MI->CapOperands, MI->Operands);
 430   // Don't call ~MachineInstr() which must be trivial anyway because
 431   // ~MachineFunction drops whole lists of MachineInstrs wihout calling their
 432   // destructors.
 433   InstructionRecycler.Deallocate(Allocator, MI);
 434 }
 435
 436 /// Allocate a new MachineBasicBlock. Use this instead of
 437 /// `new MachineBasicBlock'.
 438 MachineBasicBlock *
 439 MachineFunction::CreateMachineBasicBlock(const BasicBlock *bb) {
 440   return new (BasicBlockRecycler.Allocate<MachineBasicBlock>(Allocator))
 441              MachineBasicBlock(*this, bb);
 442 }
 443
 444 /// Delete the given MachineBasicBlock.
 445 void MachineFunction::deleteMachineBasicBlock(MachineBasicBlock *MBB) {
 446   assert(MBB->getParent() == this && "MBB parent mismatch!");
 447   // Clean up any references to MBB in jump tables before deleting it.
 448   if (JumpTableInfo)
 449     JumpTableInfo->RemoveMBBFromJumpTables(MBB);
 450   MBB->~MachineBasicBlock();
 451   BasicBlockRecycler.Deallocate(Allocator, MBB);
 452 }
 453
 454 MachineMemOperand *MachineFunction::getMachineMemOperand(
 455     MachinePointerInfo PtrInfo, MachineMemOperand::Flags f, uint64_t s,
 456     Align base_alignment, const AAMDNodes &AAInfo, const MDNode *Ranges,
 457     SyncScope::ID SSID, AtomicOrdering Ordering,
 458     AtomicOrdering FailureOrdering) {
 459   return new (Allocator)
 460       MachineMemOperand(PtrInfo, f, s, base_alignment, AAInfo, Ranges,
 461                         SSID, Ordering, FailureOrdering);
 462 }
 463
 464 MachineMemOperand *MachineFunction::getMachineMemOperand(
 465     MachinePointerInfo PtrInfo, MachineMemOperand::Flags f, LLT MemTy,
 466     Align base_alignment, const AAMDNodes &AAInfo, const MDNode *Ranges,
 467     SyncScope::ID SSID, AtomicOrdering Ordering,
 468     AtomicOrdering FailureOrdering) {
 469   return new (Allocator)
 470       MachineMemOperand(PtrInfo, f, MemTy, base_alignment, AAInfo, Ranges, SSID,
 471                         Ordering, FailureOrdering);
 472 }
 473
 474 MachineMemOperand *MachineFunction::getMachineMemOperand(
 475     const MachineMemOperand *MMO, const MachinePointerInfo &PtrInfo, uint64_t Size) {
 476   return new (Allocator)
 477       MachineMemOperand(PtrInfo, MMO->getFlags(), Size, MMO->getBaseAlign(),
 478                         AAMDNodes(), nullptr, MMO->getSyncScopeID(),
 479                         MMO->getSuccessOrdering(), MMO->getFailureOrdering());
 480 }
 481
 482 MachineMemOperand *MachineFunction::getMachineMemOperand(
 483     const MachineMemOperand *MMO, const MachinePointerInfo &PtrInfo, LLT Ty) {
 484   return new (Allocator)
 485       MachineMemOperand(PtrInfo, MMO->getFlags(), Ty, MMO->getBaseAlign(),
 486                         AAMDNodes(), nullptr, MMO->getSyncScopeID(),
 487                         MMO->getSuccessOrdering(), MMO->getFailureOrdering());
 488 }
 489
 490 MachineMemOperand *
 491 MachineFunction::getMachineMemOperand(const MachineMemOperand *MMO,
 492                                       int64_t Offset, LLT Ty) {
 493   const MachinePointerInfo &PtrInfo = MMO->getPointerInfo();
 494
 495   // If there is no pointer value, the offset isn't tracked so we need to adjust
 496   // the base alignment.
 497   Align Alignment = PtrInfo.V.isNull()
 498                         ? commonAlignment(MMO->getBaseAlign(), Offset)
 499                         : MMO->getBaseAlign();
 500
 501   // Do not preserve ranges, since we don't necessarily know what the high bits
 502   // are anymore.
 503   return new (Allocator) MachineMemOperand(
 504       PtrInfo.getWithOffset(Offset), MMO->getFlags(), Ty, Alignment,
 505       MMO->getAAInfo(), nullptr, MMO->getSyncScopeID(),
 506       MMO->getSuccessOrdering(), MMO->getFailureOrdering());
 507 }
 508
 509 MachineMemOperand *
 510 MachineFunction::getMachineMemOperand(const MachineMemOperand *MMO,
 511                                       const AAMDNodes &AAInfo) {
 512   MachinePointerInfo MPI = MMO->getValue() ?
 513              MachinePointerInfo(MMO->getValue(), MMO->getOffset()) :
 514              MachinePointerInfo(MMO->getPseudoValue(), MMO->getOffset());
 515
 516   return new (Allocator) MachineMemOperand(
 517       MPI, MMO->getFlags(), MMO->getSize(), MMO->getBaseAlign(), AAInfo,
 518       MMO->getRanges(), MMO->getSyncScopeID(), MMO->getSuccessOrdering(),
 519       MMO->getFailureOrdering());
 520 }
 521
 522 MachineMemOperand *
 523 MachineFunction::getMachineMemOperand(const MachineMemOperand *MMO,
 524                                       MachineMemOperand::Flags Flags) {
 525   return new (Allocator) MachineMemOperand(
 526       MMO->getPointerInfo(), Flags, MMO->getSize(), MMO->getBaseAlign(),
 527       MMO->getAAInfo(), MMO->getRanges(), MMO->getSyncScopeID(),
 528       MMO->getSuccessOrdering(), MMO->getFailureOrdering());
 529 }
 530
 531 MachineInstr::ExtraInfo *MachineFunction::createMIExtraInfo(
 532     ArrayRef<MachineMemOperand *> MMOs, MCSymbol *PreInstrSymbol,
 533     MCSymbol *PostInstrSymbol, MDNode *HeapAllocMarker) {
 534   return MachineInstr::ExtraInfo::create(Allocator, MMOs, PreInstrSymbol,
 535                                          PostInstrSymbol, HeapAllocMarker);
 536 }
 537
 538 const char *MachineFunction::createExternalSymbolName(StringRef Name) {
 539   char *Dest = Allocator.Allocate<char>(Name.size() + 1);
 540   llvm::copy(Name, Dest);
 541   Dest[Name.size()] = 0;
 542   return Dest;
 543 }
 544
 545 uint32_t *MachineFunction::allocateRegMask() {
 546   unsigned NumRegs = getSubtarget().getRegisterInfo()->getNumRegs();
 547   unsigned Size = MachineOperand::getRegMaskSize(NumRegs);
 548   uint32_t *Mask = Allocator.Allocate<uint32_t>(Size);
 549   memset(Mask, 0, Size * sizeof(Mask[0]));
 550   return Mask;
 551 }
 552
 553 ArrayRef<int> MachineFunction::allocateShuffleMask(ArrayRef<int> Mask) {
 554   int* AllocMask = Allocator.Allocate<int>(Mask.size());
 555   copy(Mask, AllocMask);
 556   return {AllocMask, Mask.size()};
 557 }
 558
 559 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
 560 LLVM_DUMP_METHOD void MachineFunction::dump() const {
 561   print(dbgs());
 562 }
 563 #endif
 564
 565 StringRef MachineFunction::getName() const {
 566   return getFunction().getName();
 567 }
 568
 569 void MachineFunction::print(raw_ostream &OS, const SlotIndexes *Indexes) const {
 570   OS << "# Machine code for function " << getName() << ": ";
 571   getProperties().print(OS);
 572   OS << '\n';
 573
 574   // Print Frame Information
 575   FrameInfo->print(*this, OS);
 576
 577   // Print JumpTable Information
 578   if (JumpTableInfo)
 579     JumpTableInfo->print(OS);
 580
 581   // Print Constant Pool
 582   ConstantPool->print(OS);
 583
 584   const TargetRegisterInfo *TRI = getSubtarget().getRegisterInfo();
 585
 586   if (RegInfo && !RegInfo->livein_empty()) {
 587     OS << "Function Live Ins: ";
 588     for (MachineRegisterInfo::livein_iterator
 589          I = RegInfo->livein_begin(), E = RegInfo->livein_end(); I != E; ++I) {
 590       OS << printReg(I->first, TRI);
 591       if (I->second)
 592         OS << " in " << printReg(I->second, TRI);
 593       if (std::next(I) != E)
 594         OS << ", ";
 595     }
 596     OS << '\n';
 597   }
 598
 599   ModuleSlotTracker MST(getFunction().getParent());
 600   MST.incorporateFunction(getFunction());
 601   for (const auto &BB : *this) {
 602     OS << '\n';
 603     // If we print the whole function, print it at its most verbose level.
 604     BB.print(OS, MST, Indexes, /*IsStandalone=*/true);
 605   }
 606
 607   OS << "\n# End machine code for function " << getName() << ".\n\n";
 608 }
 609
 610 /// True if this function needs frame moves for debug or exceptions.
 611 bool MachineFunction::needsFrameMoves() const {
 612   return getMMI().hasDebugInfo() ||
 613          getTarget().Options.ForceDwarfFrameSection ||
 614          F.needsUnwindTableEntry();
 615 }
 616
 617 namespace llvm {
 618
 619   template<>
 620   struct DOTGraphTraits<const MachineFunction*> : public DefaultDOTGraphTraits {
 621     DOTGraphTraits(bool isSimple = false) : DefaultDOTGraphTraits(isSimple) {}
 622
 623     static std::string getGraphName(const MachineFunction *F) {
 624       return ("CFG for '" + F->getName() + "' function").str();
 625     }
 626
 627     std::string getNodeLabel(const MachineBasicBlock *Node,
 628                              const MachineFunction *Graph) {
 629       std::string OutStr;
 630       {
 631         raw_string_ostream OSS(OutStr);
 632
 633         if (isSimple()) {
 634           OSS << printMBBReference(*Node);
 635           if (const BasicBlock *BB = Node->getBasicBlock())
 636             OSS << ": " << BB->getName();
 637         } else
 638           Node->print(OSS);
 639       }
 640
 641       if (OutStr[0] == '\n') OutStr.erase(OutStr.begin());
 642
 643       // Process string output to make it nicer...
 644       for (unsigned i = 0; i != OutStr.length(); ++i)
 645         if (OutStr[i] == '\n') {                            // Left justify
 646           OutStr[i] = '\\';
 647           OutStr.insert(OutStr.begin()+i+1, 'l');
 648         }
 649       return OutStr;
 650     }
 651   };
 652
 653 } // end namespace llvm
 654
 655 void MachineFunction::viewCFG() const
 656 {
 657 #ifndef NDEBUG
 658   ViewGraph(this, "mf" + getName());
 659 #else
 660   errs() << "MachineFunction::viewCFG is only available in debug builds on "
 661          << "systems with Graphviz or gv!\n";
 662 #endif // NDEBUG
 663 }
 664
 665 void MachineFunction::viewCFGOnly() const
 666 {
 667 #ifndef NDEBUG
 668   ViewGraph(this, "mf" + getName(), true);
 669 #else
 670   errs() << "MachineFunction::viewCFGOnly is only available in debug builds on "
 671          << "systems with Graphviz or gv!\n";
 672 #endif // NDEBUG
 673 }
 674
 675 /// Add the specified physical register as a live-in value and
 676 /// create a corresponding virtual register for it.
 677 Register MachineFunction::addLiveIn(MCRegister PReg,
 678                                     const TargetRegisterClass *RC) {
 679   MachineRegisterInfo &MRI = getRegInfo();
 680   Register VReg = MRI.getLiveInVirtReg(PReg);
 681   if (VReg) {
 682     const TargetRegisterClass *VRegRC = MRI.getRegClass(VReg);
 683     (void)VRegRC;
 684     // A physical register can be added several times.
 685     // Between two calls, the register class of the related virtual register
 686     // may have been constrained to match some operation constraints.
 687     // In that case, check that the current register class includes the
 688     // physical register and is a sub class of the specified RC.
 689     assert((VRegRC == RC || (VRegRC->contains(PReg) &&
 690                              RC->hasSubClassEq(VRegRC))) &&
 691             "Register class mismatch!");
 692     return VReg;
 693   }
 694   VReg = MRI.createVirtualRegister(RC);
 695   MRI.addLiveIn(PReg, VReg);
 696   return VReg;
 697 }
 698
 699 /// Return the MCSymbol for the specified non-empty jump table.
 700 /// If isLinkerPrivate is specified, an 'l' label is returned, otherwise a
 701 /// normal 'L' label is returned.
 702 MCSymbol *MachineFunction::getJTISymbol(unsigned JTI, MCContext &Ctx,
 703                                         bool isLinkerPrivate) const {
 704   const DataLayout &DL = getDataLayout();
 705   assert(JumpTableInfo && "No jump tables");
 706   assert(JTI < JumpTableInfo->getJumpTables().size() && "Invalid JTI!");
 707
 708   StringRef Prefix = isLinkerPrivate ? DL.getLinkerPrivateGlobalPrefix()
 709                                      : DL.getPrivateGlobalPrefix();
 710   SmallString<60> Name;
 711   raw_svector_ostream(Name)
 712     << Prefix << "JTI" << getFunctionNumber() << '_' << JTI;
 713   return Ctx.getOrCreateSymbol(Name);
 714 }
 715
 716 /// Return a function-local symbol to represent the PIC base.
 717 MCSymbol *MachineFunction::getPICBaseSymbol() const {
 718   const DataLayout &DL = getDataLayout();
 719   return Ctx.getOrCreateSymbol(Twine(DL.getPrivateGlobalPrefix()) +
 720                                Twine(getFunctionNumber()) + "$pb");
 721 }
 722
 723 /// \name Exception Handling
 724 /// \{
 725
 726 LandingPadInfo &
 727 MachineFunction::getOrCreateLandingPadInfo(MachineBasicBlock *LandingPad) {
 728   unsigned N = LandingPads.size();
 729   for (unsigned i = 0; i < N; ++i) {
 730     LandingPadInfo &LP = LandingPads[i];
 731     if (LP.LandingPadBlock == LandingPad)
 732       return LP;
 733   }
 734
 735   LandingPads.push_back(LandingPadInfo(LandingPad));
 736   return LandingPads[N];
 737 }
 738
 739 void MachineFunction::addInvoke(MachineBasicBlock *LandingPad,
 740                                 MCSymbol *BeginLabel, MCSymbol *EndLabel) {
 741   LandingPadInfo &LP = getOrCreateLandingPadInfo(LandingPad);
 742   LP.BeginLabels.push_back(BeginLabel);
 743   LP.EndLabels.push_back(EndLabel);
 744 }
 745
 746 MCSymbol *MachineFunction::addLandingPad(MachineBasicBlock *LandingPad) {
 747   MCSymbol *LandingPadLabel = Ctx.createTempSymbol();
 748   LandingPadInfo &LP = getOrCreateLandingPadInfo(LandingPad);
 749   LP.LandingPadLabel = LandingPadLabel;
 750
 751   const Instruction *FirstI = LandingPad->getBasicBlock()->getFirstNonPHI();
 752   if (const auto *LPI = dyn_cast<LandingPadInst>(FirstI)) {
 753     if (const auto *PF =
 754             dyn_cast<Function>(F.getPersonalityFn()->stripPointerCasts()))
 755       getMMI().addPersonality(PF);
 756
 757     if (LPI->isCleanup())
 758       addCleanup(LandingPad);
 759
 760     // FIXME: New EH - Add the clauses in reverse order. This isn't 100%
 761     //        correct, but we need to do it this way because of how the DWARF EH
 762     //        emitter processes the clauses.
 763     for (unsigned I = LPI->getNumClauses(); I != 0; --I) {
 764       Value *Val = LPI->getClause(I - 1);
 765       if (LPI->isCatch(I - 1)) {
 766         addCatchTypeInfo(LandingPad,
 767                          dyn_cast<GlobalValue>(Val->stripPointerCasts()));
 768       } else {
 769         // Add filters in a list.
 770         auto *CVal = cast<Constant>(Val);
 771         SmallVector<const GlobalValue *, 4> FilterList;
 772         for (const Use &U : CVal->operands())
 773           FilterList.push_back(cast<GlobalValue>(U->stripPointerCasts()));
 774
 775         addFilterTypeInfo(LandingPad, FilterList);
 776       }
 777     }
 778
 779   } else if (const auto *CPI = dyn_cast<CatchPadInst>(FirstI)) {
 780     for (unsigned I = CPI->getNumArgOperands(); I != 0; --I) {
 781       Value *TypeInfo = CPI->getArgOperand(I - 1)->stripPointerCasts();
 782       addCatchTypeInfo(LandingPad, dyn_cast<GlobalValue>(TypeInfo));
 783     }
 784
 785   } else {
 786     assert(isa<CleanupPadInst>(FirstI) && "Invalid landingpad!");
 787   }
 788
 789   return LandingPadLabel;
 790 }
 791
 792 void MachineFunction::addCatchTypeInfo(MachineBasicBlock *LandingPad,
 793                                        ArrayRef<const GlobalValue *> TyInfo) {
 794   LandingPadInfo &LP = getOrCreateLandingPadInfo(LandingPad);
 795   for (const GlobalValue *GV : llvm::reverse(TyInfo))
 796     LP.TypeIds.push_back(getTypeIDFor(GV));
 797 }
 798
 799 void MachineFunction::addFilterTypeInfo(MachineBasicBlock *LandingPad,
 800                                         ArrayRef<const GlobalValue *> TyInfo) {
 801   LandingPadInfo &LP = getOrCreateLandingPadInfo(LandingPad);
 802   std::vector<unsigned> IdsInFilter(TyInfo.size());
 803   for (unsigned I = 0, E = TyInfo.size(); I != E; ++I)
 804     IdsInFilter[I] = getTypeIDFor(TyInfo[I]);
 805   LP.TypeIds.push_back(getFilterIDFor(IdsInFilter));
 806 }
 807
 808 void MachineFunction::tidyLandingPads(DenseMap<MCSymbol *, uintptr_t> *LPMap,
 809                                       bool TidyIfNoBeginLabels) {
 810   for (unsigned i = 0; i != LandingPads.size(); ) {
 811     LandingPadInfo &LandingPad = LandingPads[i];
 812     if (LandingPad.LandingPadLabel &&
 813         !LandingPad.LandingPadLabel->isDefined() &&
 814         (!LPMap || (*LPMap)[LandingPad.LandingPadLabel] == 0))
 815       LandingPad.LandingPadLabel = nullptr;
 816
 817     // Special case: we *should* emit LPs with null LP MBB. This indicates
 818     // "nounwind" case.
 819     if (!LandingPad.LandingPadLabel && LandingPad.LandingPadBlock) {
 820       LandingPads.erase(LandingPads.begin() + i);
 821       continue;
 822     }
 823
 824     if (TidyIfNoBeginLabels) {
 825       for (unsigned j = 0, e = LandingPads[i].BeginLabels.size(); j != e; ++j) {
 826         MCSymbol *BeginLabel = LandingPad.BeginLabels[j];
 827         MCSymbol *EndLabel = LandingPad.EndLabels[j];
 828         if ((BeginLabel->isDefined() || (LPMap && (*LPMap)[BeginLabel] != 0)) &&
 829             (EndLabel->isDefined() || (LPMap && (*LPMap)[EndLabel] != 0)))
 830           continue;
 831
 832         LandingPad.BeginLabels.erase(LandingPad.BeginLabels.begin() + j);
 833         LandingPad.EndLabels.erase(LandingPad.EndLabels.begin() + j);
 834         --j;
 835         --e;
 836       }
 837
 838       // Remove landing pads with no try-ranges.
 839       if (LandingPads[i].BeginLabels.empty()) {
 840         LandingPads.erase(LandingPads.begin() + i);
 841         continue;
 842       }
 843     }
 844
 845     // If there is no landing pad, ensure that the list of typeids is empty.
 846     // If the only typeid is a cleanup, this is the same as having no typeids.
 847     if (!LandingPad.LandingPadBlock ||
 848         (LandingPad.TypeIds.size() == 1 && !LandingPad.TypeIds[0]))
 849       LandingPad.TypeIds.clear();
 850     ++i;
 851   }
 852 }
 853
 854 void MachineFunction::addCleanup(MachineBasicBlock *LandingPad) {
 855   LandingPadInfo &LP = getOrCreateLandingPadInfo(LandingPad);
 856   LP.TypeIds.push_back(0);
 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 (const 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(
1016     MachineInstr &MI, DenseMap<Register, DebugInstrOperandPair> &DbgPHICache)
1017     -> DebugInstrOperandPair {
1018   const TargetInstrInfo &TII = *getSubtarget().getInstrInfo();
1019
1020   // Check whether this copy-like instruction has already been salvaged into
1021   // an operand pair.
1022   Register Dest;
1023   if (auto CopyDstSrc = TII.isCopyInstr(MI)) {
1024     Dest = CopyDstSrc->Destination->getReg();
1025   } else {
1026     assert(MI.isSubregToReg());
1027     Dest = MI.getOperand(0).getReg();
1028   }
1029
1030   auto CacheIt = DbgPHICache.find(Dest);
1031   if (CacheIt != DbgPHICache.end())
1032     return CacheIt->second;
1033
1034   // Calculate the instruction number to use, or install a DBG_PHI.
1035   auto OperandPair = salvageCopySSAImpl(MI);
1036   DbgPHICache.insert({Dest, OperandPair});
1037   return OperandPair;
1038 }
1039
1040 auto MachineFunction::salvageCopySSAImpl(MachineInstr &MI)
1041     -> DebugInstrOperandPair {
1042   MachineRegisterInfo &MRI = getRegInfo();
1043   const TargetRegisterInfo &TRI = *MRI.getTargetRegisterInfo();
1044   const TargetInstrInfo &TII = *getSubtarget().getInstrInfo();
1045
1046   // Chase the value read by a copy-like instruction back to the instruction
1047   // that ultimately _defines_ that value. This may pass:
1048   //  * Through multiple intermediate copies, including subregister moves /
1049   //    copies,
1050   //  * Copies from physical registers that must then be traced back to the
1051   //    defining instruction,
1052   //  * Or, physical registers may be live-in to (only) the entry block, which
1053   //    requires a DBG_PHI to be created.
1054   // We can pursue this problem in that order: trace back through copies,
1055   // optionally through a physical register, to a defining instruction. We
1056   // should never move from physreg to vreg. As we're still in SSA form, no need
1057   // to worry about partial definitions of registers.
1058
1059   // Helper lambda to interpret a copy-like instruction. Takes instruction,
1060   // returns the register read and any subregister identifying which part is
1061   // read.
1062   auto GetRegAndSubreg =
1063       [&](const MachineInstr &Cpy) -> std::pair<Register, unsigned> {
1064     Register NewReg, OldReg;
1065     unsigned SubReg;
1066     if (Cpy.isCopy()) {
1067       OldReg = Cpy.getOperand(0).getReg();
1068       NewReg = Cpy.getOperand(1).getReg();
1069       SubReg = Cpy.getOperand(1).getSubReg();
1070     } else if (Cpy.isSubregToReg()) {
1071       OldReg = Cpy.getOperand(0).getReg();
1072       NewReg = Cpy.getOperand(2).getReg();
1073       SubReg = Cpy.getOperand(3).getImm();
1074     } else {
1075       auto CopyDetails = *TII.isCopyInstr(Cpy);
1076       const MachineOperand &Src = *CopyDetails.Source;
1077       const MachineOperand &Dest = *CopyDetails.Destination;
1078       OldReg = Dest.getReg();
1079       NewReg = Src.getReg();
1080       SubReg = Src.getSubReg();
1081     }
1082
1083     return {NewReg, SubReg};
1084   };
1085
1086   // First seek either the defining instruction, or a copy from a physreg.
1087   // During search, the current state is the current copy instruction, and which
1088   // register we've read. Accumulate qualifying subregisters into SubregsSeen;
1089   // deal with those later.
1090   auto State = GetRegAndSubreg(MI);
1091   auto CurInst = MI.getIterator();
1092   SmallVector<unsigned, 4> SubregsSeen;
1093   while (true) {
1094     // If we've found a copy from a physreg, first portion of search is over.
1095     if (!State.first.isVirtual())
1096       break;
1097
1098     // Record any subregister qualifier.
1099     if (State.second)
1100       SubregsSeen.push_back(State.second);
1101
1102     assert(MRI.hasOneDef(State.first));
1103     MachineInstr &Inst = *MRI.def_begin(State.first)->getParent();
1104     CurInst = Inst.getIterator();
1105
1106     // Any non-copy instruction is the defining instruction we're seeking.
1107     if (!Inst.isCopyLike() && !TII.isCopyInstr(Inst))
1108       break;
1109     State = GetRegAndSubreg(Inst);
1110   };
1111
1112   // Helper lambda to apply additional subregister substitutions to a known
1113   // instruction/operand pair. Adds new (fake) substitutions so that we can
1114   // record the subregister. FIXME: this isn't very space efficient if multiple
1115   // values are tracked back through the same copies; cache something later.
1116   auto ApplySubregisters =
1117       [&](DebugInstrOperandPair P) -> DebugInstrOperandPair {
1118     for (unsigned Subreg : reverse(SubregsSeen)) {
1119       // Fetch a new instruction number, not attached to an actual instruction.
1120       unsigned NewInstrNumber = getNewDebugInstrNum();
1121       // Add a substitution from the "new" number to the known one, with a
1122       // qualifying subreg.
1123       makeDebugValueSubstitution({NewInstrNumber, 0}, P, Subreg);
1124       // Return the new number; to find the underlying value, consumers need to
1125       // deal with the qualifying subreg.
1126       P = {NewInstrNumber, 0};
1127     }
1128     return P;
1129   };
1130
1131   // If we managed to find the defining instruction after COPYs, return an
1132   // instruction / operand pair after adding subregister qualifiers.
1133   if (State.first.isVirtual()) {
1134     // Virtual register def -- we can just look up where this happens.
1135     MachineInstr *Inst = MRI.def_begin(State.first)->getParent();
1136     for (auto &MO : Inst->operands()) {
1137       if (!MO.isReg() || !MO.isDef() || MO.getReg() != State.first)
1138         continue;
1139       return ApplySubregisters(
1140           {Inst->getDebugInstrNum(), Inst->getOperandNo(&MO)});
1141     }
1142
1143     llvm_unreachable("Vreg def with no corresponding operand?");
1144   }
1145
1146   // Our search ended in a copy from a physreg: walk back up the function
1147   // looking for whatever defines the physreg.
1148   assert(CurInst->isCopyLike() || TII.isCopyInstr(*CurInst));
1149   State = GetRegAndSubreg(*CurInst);
1150   Register RegToSeek = State.first;
1151
1152   auto RMII = CurInst->getReverseIterator();
1153   auto PrevInstrs = make_range(RMII, CurInst->getParent()->instr_rend());
1154   for (auto &ToExamine : PrevInstrs) {
1155     for (auto &MO : ToExamine.operands()) {
1156       // Test for operand that defines something aliasing RegToSeek.
1157       if (!MO.isReg() || !MO.isDef() ||
1158           !TRI.regsOverlap(RegToSeek, MO.getReg()))
1159         continue;
1160
1161       return ApplySubregisters(
1162           {ToExamine.getDebugInstrNum(), ToExamine.getOperandNo(&MO)});
1163     }
1164   }
1165
1166   MachineBasicBlock &InsertBB = *CurInst->getParent();
1167
1168   // We reached the start of the block before finding a defining instruction.
1169   // There are numerous scenarios where this can happen:
1170   // * Constant physical registers,
1171   // * Several intrinsics that allow LLVM-IR to read arbitary registers,
1172   // * Arguments in the entry block,
1173   // * Exception handling landing pads.
1174   // Validating all of them is too difficult, so just insert a DBG_PHI reading
1175   // the variable value at this position, rather than checking it makes sense.
1176
1177   // Create DBG_PHI for specified physreg.
1178   auto Builder = BuildMI(InsertBB, InsertBB.getFirstNonPHI(), DebugLoc(),
1179                          TII.get(TargetOpcode::DBG_PHI));
1180   Builder.addReg(State.first);
1181   unsigned NewNum = getNewDebugInstrNum();
1182   Builder.addImm(NewNum);
1183   return ApplySubregisters({NewNum, 0u});
1184 }
1185
1186 void MachineFunction::finalizeDebugInstrRefs() {
1187   auto *TII = getSubtarget().getInstrInfo();
1188
1189   auto MakeUndefDbgValue = [&](MachineInstr &MI) {
1190     const MCInstrDesc &RefII = TII->get(TargetOpcode::DBG_VALUE);
1191     MI.setDesc(RefII);
1192     MI.getOperand(0).setReg(0);
1193     MI.getOperand(1).ChangeToRegister(0, false);
1194   };
1195
1196   DenseMap<Register, DebugInstrOperandPair> ArgDbgPHIs;
1197   for (auto &MBB : *this) {
1198     for (auto &MI : MBB) {
1199       if (!MI.isDebugRef() || !MI.getOperand(0).isReg())
1200         continue;
1201
1202       Register Reg = MI.getOperand(0).getReg();
1203
1204       // Some vregs can be deleted as redundant in the meantime. Mark those
1205       // as DBG_VALUE $noreg. Additionally, some normal instructions are
1206       // quickly deleted, leaving dangling references to vregs with no def.
1207       if (Reg == 0 || !RegInfo->hasOneDef(Reg)) {
1208         MakeUndefDbgValue(MI);
1209         continue;
1210       }
1211
1212       assert(Reg.isVirtual());
1213       MachineInstr &DefMI = *RegInfo->def_instr_begin(Reg);
1214
1215       // If we've found a copy-like instruction, follow it back to the
1216       // instruction that defines the source value, see salvageCopySSA docs
1217       // for why this is important.
1218       if (DefMI.isCopyLike() || TII->isCopyInstr(DefMI)) {
1219         auto Result = salvageCopySSA(DefMI, ArgDbgPHIs);
1220         MI.getOperand(0).ChangeToImmediate(Result.first);
1221         MI.getOperand(1).setImm(Result.second);
1222       } else {
1223         // Otherwise, identify the operand number that the VReg refers to.
1224         unsigned OperandIdx = 0;
1225         for (const auto &MO : DefMI.operands()) {
1226           if (MO.isReg() && MO.isDef() && MO.getReg() == Reg)
1227             break;
1228           ++OperandIdx;
1229         }
1230         assert(OperandIdx < DefMI.getNumOperands());
1231
1232         // Morph this instr ref to point at the given instruction and operand.
1233         unsigned ID = DefMI.getDebugInstrNum();
1234         MI.getOperand(0).ChangeToImmediate(ID);
1235         MI.getOperand(1).setImm(OperandIdx);
1236       }
1237     }
1238   }
1239 }
1240
1241 bool MachineFunction::useDebugInstrRef() const {
1242   // Disable instr-ref at -O0: it's very slow (in compile time). We can still
1243   // have optimized code inlined into this unoptimized code, however with
1244   // fewer and less aggressive optimizations happening, coverage and accuracy
1245   // should not suffer.
1246   if (getTarget().getOptLevel() == CodeGenOpt::None)
1247     return false;
1248
1249   // Don't use instr-ref if this function is marked optnone.
1250   if (F.hasFnAttribute(Attribute::OptimizeNone))
1251     return false;
1252
1253   if (llvm::debuginfoShouldUseDebugInstrRef(getTarget().getTargetTriple()))
1254     return true;
1255
1256   return false;
1257 }
1258
1259 // Use one million as a high / reserved number.
1260 const unsigned MachineFunction::DebugOperandMemNumber = 1000000;
1261
1262 /// \}
1263
1264 //===----------------------------------------------------------------------===//
1265 //  MachineJumpTableInfo implementation
1266 //===----------------------------------------------------------------------===//
1267
1268 /// Return the size of each entry in the jump table.
1269 unsigned MachineJumpTableInfo::getEntrySize(const DataLayout &TD) const {
1270   // The size of a jump table entry is 4 bytes unless the entry is just the
1271   // address of a block, in which case it is the pointer size.
1272   switch (getEntryKind()) {
1273   case MachineJumpTableInfo::EK_BlockAddress:
1274     return TD.getPointerSize();
1275   case MachineJumpTableInfo::EK_GPRel64BlockAddress:
1276     return 8;
1277   case MachineJumpTableInfo::EK_GPRel32BlockAddress:
1278   case MachineJumpTableInfo::EK_LabelDifference32:
1279   case MachineJumpTableInfo::EK_Custom32:
1280     return 4;
1281   case MachineJumpTableInfo::EK_Inline:
1282     return 0;
1283   }
1284   llvm_unreachable("Unknown jump table encoding!");
1285 }
1286
1287 /// Return the alignment of each entry in the jump table.
1288 unsigned MachineJumpTableInfo::getEntryAlignment(const DataLayout &TD) const {
1289   // The alignment of a jump table entry is the alignment of int32 unless the
1290   // entry is just the address of a block, in which case it is the pointer
1291   // alignment.
1292   switch (getEntryKind()) {
1293   case MachineJumpTableInfo::EK_BlockAddress:
1294     return TD.getPointerABIAlignment(0).value();
1295   case MachineJumpTableInfo::EK_GPRel64BlockAddress:
1296     return TD.getABIIntegerTypeAlignment(64).value();
1297   case MachineJumpTableInfo::EK_GPRel32BlockAddress:
1298   case MachineJumpTableInfo::EK_LabelDifference32:
1299   case MachineJumpTableInfo::EK_Custom32:
1300     return TD.getABIIntegerTypeAlignment(32).value();
1301   case MachineJumpTableInfo::EK_Inline:
1302     return 1;
1303   }
1304   llvm_unreachable("Unknown jump table encoding!");
1305 }
1306
1307 /// Create a new jump table entry in the jump table info.
1308 unsigned MachineJumpTableInfo::createJumpTableIndex(
1309                                const std::vector<MachineBasicBlock*> &DestBBs) {
1310   assert(!DestBBs.empty() && "Cannot create an empty jump table!");
1311   JumpTables.push_back(MachineJumpTableEntry(DestBBs));
1312   return JumpTables.size()-1;
1313 }
1314
1315 /// If Old is the target of any jump tables, update the jump tables to branch
1316 /// to New instead.
1317 bool MachineJumpTableInfo::ReplaceMBBInJumpTables(MachineBasicBlock *Old,
1318                                                   MachineBasicBlock *New) {
1319   assert(Old != New && "Not making a change?");
1320   bool MadeChange = false;
1321   for (size_t i = 0, e = JumpTables.size(); i != e; ++i)
1322     ReplaceMBBInJumpTable(i, Old, New);
1323   return MadeChange;
1324 }
1325
1326 /// If MBB is present in any jump tables, remove it.
1327 bool MachineJumpTableInfo::RemoveMBBFromJumpTables(MachineBasicBlock *MBB) {
1328   bool MadeChange = false;
1329   for (MachineJumpTableEntry &JTE : JumpTables) {
1330     auto removeBeginItr = std::remove(JTE.MBBs.begin(), JTE.MBBs.end(), MBB);
1331     MadeChange |= (removeBeginItr != JTE.MBBs.end());
1332     JTE.MBBs.erase(removeBeginItr, JTE.MBBs.end());
1333   }
1334   return MadeChange;
1335 }
1336
1337 /// If Old is a target of the jump tables, update the jump table to branch to
1338 /// New instead.
1339 bool MachineJumpTableInfo::ReplaceMBBInJumpTable(unsigned Idx,
1340                                                  MachineBasicBlock *Old,
1341                                                  MachineBasicBlock *New) {
1342   assert(Old != New && "Not making a change?");
1343   bool MadeChange = false;
1344   MachineJumpTableEntry &JTE = JumpTables[Idx];
1345   for (MachineBasicBlock *&MBB : JTE.MBBs)
1346     if (MBB == Old) {
1347       MBB = New;
1348       MadeChange = true;
1349     }
1350   return MadeChange;
1351 }
1352
1353 void MachineJumpTableInfo::print(raw_ostream &OS) const {
1354   if (JumpTables.empty()) return;
1355
1356   OS << "Jump Tables:\n";
1357
1358   for (unsigned i = 0, e = JumpTables.size(); i != e; ++i) {
1359     OS << printJumpTableEntryReference(i) << ':';
1360     for (const MachineBasicBlock *MBB : JumpTables[i].MBBs)
1361       OS << ' ' << printMBBReference(*MBB);
1362     if (i != e)
1363       OS << '\n';
1364   }
1365
1366   OS << '\n';
1367 }
1368
1369 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
1370 LLVM_DUMP_METHOD void MachineJumpTableInfo::dump() const { print(dbgs()); }
1371 #endif
1372
1373 Printable llvm::printJumpTableEntryReference(unsigned Idx) {
1374   return Printable([Idx](raw_ostream &OS) { OS << "%jump-table." << Idx; });
1375 }
1376
1377 //===----------------------------------------------------------------------===//
1378 //  MachineConstantPool implementation
1379 //===----------------------------------------------------------------------===//
1380
1381 void MachineConstantPoolValue::anchor() {}
1382
1383 unsigned MachineConstantPoolValue::getSizeInBytes(const DataLayout &DL) const {
1384   return DL.getTypeAllocSize(Ty);
1385 }
1386
1387 unsigned MachineConstantPoolEntry::getSizeInBytes(const DataLayout &DL) const {
1388   if (isMachineConstantPoolEntry())
1389     return Val.MachineCPVal->getSizeInBytes(DL);
1390   return DL.getTypeAllocSize(Val.ConstVal->getType());
1391 }
1392
1393 bool MachineConstantPoolEntry::needsRelocation() const {
1394   if (isMachineConstantPoolEntry())
1395     return true;
1396   return Val.ConstVal->needsDynamicRelocation();
1397 }
1398
1399 SectionKind
1400 MachineConstantPoolEntry::getSectionKind(const DataLayout *DL) const {
1401   if (needsRelocation())
1402     return SectionKind::getReadOnlyWithRel();
1403   switch (getSizeInBytes(*DL)) {
1404   case 4:
1405     return SectionKind::getMergeableConst4();
1406   case 8:
1407     return SectionKind::getMergeableConst8();
1408   case 16:
1409     return SectionKind::getMergeableConst16();
1410   case 32:
1411     return SectionKind::getMergeableConst32();
1412   default:
1413     return SectionKind::getReadOnly();
1414   }
1415 }
1416
1417 MachineConstantPool::~MachineConstantPool() {
1418   // A constant may be a member of both Constants and MachineCPVsSharingEntries,
1419   // so keep track of which we've deleted to avoid double deletions.
1420   DenseSet<MachineConstantPoolValue*> Deleted;
1421   for (const MachineConstantPoolEntry &C : Constants)
1422     if (C.isMachineConstantPoolEntry()) {
1423       Deleted.insert(C.Val.MachineCPVal);
1424       delete C.Val.MachineCPVal;
1425     }
1426   for (MachineConstantPoolValue *CPV : MachineCPVsSharingEntries) {
1427     if (Deleted.count(CPV) == 0)
1428       delete CPV;
1429   }
1430 }
1431
1432 /// Test whether the given two constants can be allocated the same constant pool
1433 /// entry.
1434 static bool CanShareConstantPoolEntry(const Constant *A, const Constant *B,
1435                                       const DataLayout &DL) {
1436   // Handle the trivial case quickly.
1437   if (A == B) return true;
1438
1439   // If they have the same type but weren't the same constant, quickly
1440   // reject them.
1441   if (A->getType() == B->getType()) return false;
1442
1443   // We can't handle structs or arrays.
1444   if (isa<StructType>(A->getType()) || isa<ArrayType>(A->getType()) ||
1445       isa<StructType>(B->getType()) || isa<ArrayType>(B->getType()))
1446     return false;
1447
1448   // For now, only support constants with the same size.
1449   uint64_t StoreSize = DL.getTypeStoreSize(A->getType());
1450   if (StoreSize != DL.getTypeStoreSize(B->getType()) || StoreSize > 128)
1451     return false;
1452
1453   Type *IntTy = IntegerType::get(A->getContext(), StoreSize*8);
1454
1455   // Try constant folding a bitcast of both instructions to an integer.  If we
1456   // get two identical ConstantInt's, then we are good to share them.  We use
1457   // the constant folding APIs to do this so that we get the benefit of
1458   // DataLayout.
1459   if (isa<PointerType>(A->getType()))
1460     A = ConstantFoldCastOperand(Instruction::PtrToInt,
1461                                 const_cast<Constant *>(A), IntTy, DL);
1462   else if (A->getType() != IntTy)
1463     A = ConstantFoldCastOperand(Instruction::BitCast, const_cast<Constant *>(A),
1464                                 IntTy, DL);
1465   if (isa<PointerType>(B->getType()))
1466     B = ConstantFoldCastOperand(Instruction::PtrToInt,
1467                                 const_cast<Constant *>(B), IntTy, DL);
1468   else if (B->getType() != IntTy)
1469     B = ConstantFoldCastOperand(Instruction::BitCast, const_cast<Constant *>(B),
1470                                 IntTy, DL);
1471
1472   return A == B;
1473 }
1474
1475 /// Create a new entry in the constant pool or return an existing one.
1476 /// User must specify the log2 of the minimum required alignment for the object.
1477 unsigned MachineConstantPool::getConstantPoolIndex(const Constant *C,
1478                                                    Align Alignment) {
1479   if (Alignment > PoolAlignment) PoolAlignment = Alignment;
1480
1481   // Check to see if we already have this constant.
1482   //
1483   // FIXME, this could be made much more efficient for large constant pools.
1484   for (unsigned i = 0, e = Constants.size(); i != e; ++i)
1485     if (!Constants[i].isMachineConstantPoolEntry() &&
1486         CanShareConstantPoolEntry(Constants[i].Val.ConstVal, C, DL)) {
1487       if (Constants[i].getAlign() < Alignment)
1488         Constants[i].Alignment = Alignment;
1489       return i;
1490     }
1491
1492   Constants.push_back(MachineConstantPoolEntry(C, Alignment));
1493   return Constants.size()-1;
1494 }
1495
1496 unsigned MachineConstantPool::getConstantPoolIndex(MachineConstantPoolValue *V,
1497                                                    Align Alignment) {
1498   if (Alignment > PoolAlignment) PoolAlignment = Alignment;
1499
1500   // Check to see if we already have this constant.
1501   //
1502   // FIXME, this could be made much more efficient for large constant pools.
1503   int Idx = V->getExistingMachineCPValue(this, Alignment);
1504   if (Idx != -1) {
1505     MachineCPVsSharingEntries.insert(V);
1506     return (unsigned)Idx;
1507   }
1508
1509   Constants.push_back(MachineConstantPoolEntry(V, Alignment));
1510   return Constants.size()-1;
1511 }
1512
1513 void MachineConstantPool::print(raw_ostream &OS) const {
1514   if (Constants.empty()) return;
1515
1516   OS << "Constant Pool:\n";
1517   for (unsigned i = 0, e = Constants.size(); i != e; ++i) {
1518     OS << "  cp#" << i << ": ";
1519     if (Constants[i].isMachineConstantPoolEntry())
1520       Constants[i].Val.MachineCPVal->print(OS);
1521     else
1522       Constants[i].Val.ConstVal->printAsOperand(OS, /*PrintType=*/false);
1523     OS << ", align=" << Constants[i].getAlign().value();
1524     OS << "\n";
1525   }
1526 }
1527
1528 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
1529 LLVM_DUMP_METHOD void MachineConstantPool::dump() const { print(dbgs()); }
1530 #endif