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/ProfileSummaryInfo.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/PseudoSourceValueManager.h" 36 #include "llvm/CodeGen/TargetFrameLowering.h" 37 #include "llvm/CodeGen/TargetInstrInfo.h" 38 #include "llvm/CodeGen/TargetLowering.h" 39 #include "llvm/CodeGen/TargetRegisterInfo.h" 40 #include "llvm/CodeGen/TargetSubtargetInfo.h" 41 #include "llvm/CodeGen/WasmEHFuncInfo.h" 42 #include "llvm/CodeGen/WinEHFuncInfo.h" 43 #include "llvm/Config/llvm-config.h" 44 #include "llvm/IR/Attributes.h" 45 #include "llvm/IR/BasicBlock.h" 46 #include "llvm/IR/Constant.h" 47 #include "llvm/IR/DataLayout.h" 48 #include "llvm/IR/DerivedTypes.h" 49 #include "llvm/IR/EHPersonalities.h" 50 #include "llvm/IR/Function.h" 51 #include "llvm/IR/GlobalValue.h" 52 #include "llvm/IR/Instruction.h" 53 #include "llvm/IR/Instructions.h" 54 #include "llvm/IR/Metadata.h" 55 #include "llvm/IR/Module.h" 56 #include "llvm/IR/ModuleSlotTracker.h" 57 #include "llvm/IR/Value.h" 58 #include "llvm/MC/MCContext.h" 59 #include "llvm/MC/MCSymbol.h" 60 #include "llvm/MC/SectionKind.h" 61 #include "llvm/Support/Casting.h" 62 #include "llvm/Support/CommandLine.h" 63 #include "llvm/Support/Compiler.h" 64 #include "llvm/Support/DOTGraphTraits.h" 65 #include "llvm/Support/ErrorHandling.h" 66 #include "llvm/Support/GraphWriter.h" 67 #include "llvm/Support/raw_ostream.h" 68 #include "llvm/Target/TargetMachine.h" 69 #include <algorithm> 70 #include <cassert> 71 #include <cstddef> 72 #include <cstdint> 73 #include <iterator> 74 #include <string> 75 #include <type_traits> 76 #include <utility> 77 #include <vector> 78 79 #include "LiveDebugValues/LiveDebugValues.h" 80 81 using namespace llvm; 82 83 #define DEBUG_TYPE "codegen" 84 85 static cl::opt<unsigned> AlignAllFunctions( 86 "align-all-functions", 87 cl::desc("Force the alignment of all functions in log2 format (e.g. 4 " 88 "means align on 16B boundaries)."), 89 cl::init(0), cl::Hidden); 90 91 static const char *getPropertyName(MachineFunctionProperties::Property Prop) { 92 using P = MachineFunctionProperties::Property; 93 94 // clang-format off 95 switch(Prop) { 96 case P::FailedISel: return "FailedISel"; 97 case P::IsSSA: return "IsSSA"; 98 case P::Legalized: return "Legalized"; 99 case P::NoPHIs: return "NoPHIs"; 100 case P::NoVRegs: return "NoVRegs"; 101 case P::RegBankSelected: return "RegBankSelected"; 102 case P::Selected: return "Selected"; 103 case P::TracksLiveness: return "TracksLiveness"; 104 case P::TiedOpsRewritten: return "TiedOpsRewritten"; 105 case P::FailsVerification: return "FailsVerification"; 106 case P::TracksDebugUserValues: return "TracksDebugUserValues"; 107 } 108 // clang-format on 109 llvm_unreachable("Invalid machine function property"); 110 } 111 112 void setUnsafeStackSize(const Function &F, MachineFrameInfo &FrameInfo) { 113 if (!F.hasFnAttribute(Attribute::SafeStack)) 114 return; 115 116 auto *Existing = 117 dyn_cast_or_null<MDTuple>(F.getMetadata(LLVMContext::MD_annotation)); 118 119 if (!Existing || Existing->getNumOperands() != 2) 120 return; 121 122 auto *MetadataName = "unsafe-stack-size"; 123 if (auto &N = Existing->getOperand(0)) { 124 if (N.equalsStr(MetadataName)) { 125 if (auto &Op = Existing->getOperand(1)) { 126 auto Val = mdconst::extract<ConstantInt>(Op)->getZExtValue(); 127 FrameInfo.setUnsafeStackSize(Val); 128 } 129 } 130 } 131 } 132 133 // Pin the vtable to this file. 134 void MachineFunction::Delegate::anchor() {} 135 136 void MachineFunctionProperties::print(raw_ostream &OS) const { 137 const char *Separator = ""; 138 for (BitVector::size_type I = 0; I < Properties.size(); ++I) { 139 if (!Properties[I]) 140 continue; 141 OS << Separator << getPropertyName(static_cast<Property>(I)); 142 Separator = ", "; 143 } 144 } 145 146 //===----------------------------------------------------------------------===// 147 // MachineFunction implementation 148 //===----------------------------------------------------------------------===// 149 150 // Out-of-line virtual method. 151 MachineFunctionInfo::~MachineFunctionInfo() = default; 152 153 void ilist_alloc_traits<MachineBasicBlock>::deleteNode(MachineBasicBlock *MBB) { 154 MBB->getParent()->deleteMachineBasicBlock(MBB); 155 } 156 157 static inline Align getFnStackAlignment(const TargetSubtargetInfo *STI, 158 const Function &F) { 159 if (auto MA = F.getFnStackAlign()) 160 return *MA; 161 return STI->getFrameLowering()->getStackAlign(); 162 } 163 164 MachineFunction::MachineFunction(Function &F, const LLVMTargetMachine &Target, 165 const TargetSubtargetInfo &STI, 166 unsigned FunctionNum, MachineModuleInfo &mmi) 167 : F(F), Target(Target), STI(&STI), Ctx(mmi.getContext()), MMI(mmi) { 168 FunctionNumber = FunctionNum; 169 init(); 170 } 171 172 void MachineFunction::handleInsertion(MachineInstr &MI) { 173 if (TheDelegate) 174 TheDelegate->MF_HandleInsertion(MI); 175 } 176 177 void MachineFunction::handleRemoval(MachineInstr &MI) { 178 if (TheDelegate) 179 TheDelegate->MF_HandleRemoval(MI); 180 } 181 182 void MachineFunction::handleChangeDesc(MachineInstr &MI, 183 const MCInstrDesc &TID) { 184 if (TheDelegate) 185 TheDelegate->MF_HandleChangeDesc(MI, TID); 186 } 187 188 void MachineFunction::init() { 189 // Assume the function starts in SSA form with correct liveness. 190 Properties.set(MachineFunctionProperties::Property::IsSSA); 191 Properties.set(MachineFunctionProperties::Property::TracksLiveness); 192 if (STI->getRegisterInfo()) 193 RegInfo = new (Allocator) MachineRegisterInfo(this); 194 else 195 RegInfo = nullptr; 196 197 MFInfo = nullptr; 198 199 // We can realign the stack if the target supports it and the user hasn't 200 // explicitly asked us not to. 201 bool CanRealignSP = STI->getFrameLowering()->isStackRealignable() && 202 !F.hasFnAttribute("no-realign-stack"); 203 FrameInfo = new (Allocator) MachineFrameInfo( 204 getFnStackAlignment(STI, F), /*StackRealignable=*/CanRealignSP, 205 /*ForcedRealign=*/CanRealignSP && 206 F.hasFnAttribute(Attribute::StackAlignment)); 207 208 setUnsafeStackSize(F, *FrameInfo); 209 210 if (F.hasFnAttribute(Attribute::StackAlignment)) 211 FrameInfo->ensureMaxAlignment(*F.getFnStackAlign()); 212 213 ConstantPool = new (Allocator) MachineConstantPool(getDataLayout()); 214 Alignment = STI->getTargetLowering()->getMinFunctionAlignment(); 215 216 // FIXME: Shouldn't use pref alignment if explicit alignment is set on F. 217 // FIXME: Use Function::hasOptSize(). 218 if (!F.hasFnAttribute(Attribute::OptimizeForSize)) 219 Alignment = std::max(Alignment, 220 STI->getTargetLowering()->getPrefFunctionAlignment()); 221 222 // -fsanitize=function and -fsanitize=kcfi instrument indirect function calls 223 // to load a type hash before the function label. Ensure functions are aligned 224 // by a least 4 to avoid unaligned access, which is especially important for 225 // -mno-unaligned-access. 226 if (F.hasMetadata(LLVMContext::MD_func_sanitize) || 227 F.getMetadata(LLVMContext::MD_kcfi_type)) 228 Alignment = std::max(Alignment, Align(4)); 229 230 if (AlignAllFunctions) 231 Alignment = Align(1ULL << AlignAllFunctions); 232 233 JumpTableInfo = nullptr; 234 235 if (isFuncletEHPersonality(classifyEHPersonality( 236 F.hasPersonalityFn() ? F.getPersonalityFn() : nullptr))) { 237 WinEHInfo = new (Allocator) WinEHFuncInfo(); 238 } 239 240 if (isScopedEHPersonality(classifyEHPersonality( 241 F.hasPersonalityFn() ? F.getPersonalityFn() : nullptr))) { 242 WasmEHInfo = new (Allocator) WasmEHFuncInfo(); 243 } 244 245 assert(Target.isCompatibleDataLayout(getDataLayout()) && 246 "Can't create a MachineFunction using a Module with a " 247 "Target-incompatible DataLayout attached\n"); 248 249 PSVManager = std::make_unique<PseudoSourceValueManager>(getTarget()); 250 } 251 252 void MachineFunction::initTargetMachineFunctionInfo( 253 const TargetSubtargetInfo &STI) { 254 assert(!MFInfo && "MachineFunctionInfo already set"); 255 MFInfo = Target.createMachineFunctionInfo(Allocator, F, &STI); 256 } 257 258 MachineFunction::~MachineFunction() { 259 clear(); 260 } 261 262 void MachineFunction::clear() { 263 Properties.reset(); 264 // Don't call destructors on MachineInstr and MachineOperand. All of their 265 // memory comes from the BumpPtrAllocator which is about to be purged. 266 // 267 // Do call MachineBasicBlock destructors, it contains std::vectors. 268 for (iterator I = begin(), E = end(); I != E; I = BasicBlocks.erase(I)) 269 I->Insts.clearAndLeakNodesUnsafely(); 270 MBBNumbering.clear(); 271 272 InstructionRecycler.clear(Allocator); 273 OperandRecycler.clear(Allocator); 274 BasicBlockRecycler.clear(Allocator); 275 CodeViewAnnotations.clear(); 276 VariableDbgInfos.clear(); 277 if (RegInfo) { 278 RegInfo->~MachineRegisterInfo(); 279 Allocator.Deallocate(RegInfo); 280 } 281 if (MFInfo) { 282 MFInfo->~MachineFunctionInfo(); 283 Allocator.Deallocate(MFInfo); 284 } 285 286 FrameInfo->~MachineFrameInfo(); 287 Allocator.Deallocate(FrameInfo); 288 289 ConstantPool->~MachineConstantPool(); 290 Allocator.Deallocate(ConstantPool); 291 292 if (JumpTableInfo) { 293 JumpTableInfo->~MachineJumpTableInfo(); 294 Allocator.Deallocate(JumpTableInfo); 295 } 296 297 if (WinEHInfo) { 298 WinEHInfo->~WinEHFuncInfo(); 299 Allocator.Deallocate(WinEHInfo); 300 } 301 302 if (WasmEHInfo) { 303 WasmEHInfo->~WasmEHFuncInfo(); 304 Allocator.Deallocate(WasmEHInfo); 305 } 306 } 307 308 const DataLayout &MachineFunction::getDataLayout() const { 309 return F.getParent()->getDataLayout(); 310 } 311 312 /// Get the JumpTableInfo for this function. 313 /// If it does not already exist, allocate one. 314 MachineJumpTableInfo *MachineFunction:: 315 getOrCreateJumpTableInfo(unsigned EntryKind) { 316 if (JumpTableInfo) return JumpTableInfo; 317 318 JumpTableInfo = new (Allocator) 319 MachineJumpTableInfo((MachineJumpTableInfo::JTEntryKind)EntryKind); 320 return JumpTableInfo; 321 } 322 323 DenormalMode MachineFunction::getDenormalMode(const fltSemantics &FPType) const { 324 return F.getDenormalMode(FPType); 325 } 326 327 /// Should we be emitting segmented stack stuff for the function 328 bool MachineFunction::shouldSplitStack() const { 329 return getFunction().hasFnAttribute("split-stack"); 330 } 331 332 [[nodiscard]] unsigned 333 MachineFunction::addFrameInst(const MCCFIInstruction &Inst) { 334 FrameInstructions.push_back(Inst); 335 return FrameInstructions.size() - 1; 336 } 337 338 /// This discards all of the MachineBasicBlock numbers and recomputes them. 339 /// This guarantees that the MBB numbers are sequential, dense, and match the 340 /// ordering of the blocks within the function. If a specific MachineBasicBlock 341 /// is specified, only that block and those after it are renumbered. 342 void MachineFunction::RenumberBlocks(MachineBasicBlock *MBB) { 343 if (empty()) { MBBNumbering.clear(); return; } 344 MachineFunction::iterator MBBI, E = end(); 345 if (MBB == nullptr) 346 MBBI = begin(); 347 else 348 MBBI = MBB->getIterator(); 349 350 // Figure out the block number this should have. 351 unsigned BlockNo = 0; 352 if (MBBI != begin()) 353 BlockNo = std::prev(MBBI)->getNumber() + 1; 354 355 for (; MBBI != E; ++MBBI, ++BlockNo) { 356 if (MBBI->getNumber() != (int)BlockNo) { 357 // Remove use of the old number. 358 if (MBBI->getNumber() != -1) { 359 assert(MBBNumbering[MBBI->getNumber()] == &*MBBI && 360 "MBB number mismatch!"); 361 MBBNumbering[MBBI->getNumber()] = nullptr; 362 } 363 364 // If BlockNo is already taken, set that block's number to -1. 365 if (MBBNumbering[BlockNo]) 366 MBBNumbering[BlockNo]->setNumber(-1); 367 368 MBBNumbering[BlockNo] = &*MBBI; 369 MBBI->setNumber(BlockNo); 370 } 371 } 372 373 // Okay, all the blocks are renumbered. If we have compactified the block 374 // numbering, shrink MBBNumbering now. 375 assert(BlockNo <= MBBNumbering.size() && "Mismatch!"); 376 MBBNumbering.resize(BlockNo); 377 } 378 379 /// This method iterates over the basic blocks and assigns their IsBeginSection 380 /// and IsEndSection fields. This must be called after MBB layout is finalized 381 /// and the SectionID's are assigned to MBBs. 382 void MachineFunction::assignBeginEndSections() { 383 front().setIsBeginSection(); 384 auto CurrentSectionID = front().getSectionID(); 385 for (auto MBBI = std::next(begin()), E = end(); MBBI != E; ++MBBI) { 386 if (MBBI->getSectionID() == CurrentSectionID) 387 continue; 388 MBBI->setIsBeginSection(); 389 std::prev(MBBI)->setIsEndSection(); 390 CurrentSectionID = MBBI->getSectionID(); 391 } 392 back().setIsEndSection(); 393 } 394 395 /// Allocate a new MachineInstr. Use this instead of `new MachineInstr'. 396 MachineInstr *MachineFunction::CreateMachineInstr(const MCInstrDesc &MCID, 397 DebugLoc DL, 398 bool NoImplicit) { 399 return new (InstructionRecycler.Allocate<MachineInstr>(Allocator)) 400 MachineInstr(*this, MCID, std::move(DL), NoImplicit); 401 } 402 403 /// Create a new MachineInstr which is a copy of the 'Orig' instruction, 404 /// identical in all ways except the instruction has no parent, prev, or next. 405 MachineInstr * 406 MachineFunction::CloneMachineInstr(const MachineInstr *Orig) { 407 return new (InstructionRecycler.Allocate<MachineInstr>(Allocator)) 408 MachineInstr(*this, *Orig); 409 } 410 411 MachineInstr &MachineFunction::cloneMachineInstrBundle( 412 MachineBasicBlock &MBB, MachineBasicBlock::iterator InsertBefore, 413 const MachineInstr &Orig) { 414 MachineInstr *FirstClone = nullptr; 415 MachineBasicBlock::const_instr_iterator I = Orig.getIterator(); 416 while (true) { 417 MachineInstr *Cloned = CloneMachineInstr(&*I); 418 MBB.insert(InsertBefore, Cloned); 419 if (FirstClone == nullptr) { 420 FirstClone = Cloned; 421 } else { 422 Cloned->bundleWithPred(); 423 } 424 425 if (!I->isBundledWithSucc()) 426 break; 427 ++I; 428 } 429 // Copy over call site info to the cloned instruction if needed. If Orig is in 430 // a bundle, copyCallSiteInfo takes care of finding the call instruction in 431 // the bundle. 432 if (Orig.shouldUpdateCallSiteInfo()) 433 copyCallSiteInfo(&Orig, FirstClone); 434 return *FirstClone; 435 } 436 437 /// Delete the given MachineInstr. 438 /// 439 /// This function also serves as the MachineInstr destructor - the real 440 /// ~MachineInstr() destructor must be empty. 441 void MachineFunction::deleteMachineInstr(MachineInstr *MI) { 442 // Verify that a call site info is at valid state. This assertion should 443 // be triggered during the implementation of support for the 444 // call site info of a new architecture. If the assertion is triggered, 445 // back trace will tell where to insert a call to updateCallSiteInfo(). 446 assert((!MI->isCandidateForCallSiteEntry() || !CallSitesInfo.contains(MI)) && 447 "Call site info was not updated!"); 448 // Strip it for parts. The operand array and the MI object itself are 449 // independently recyclable. 450 if (MI->Operands) 451 deallocateOperandArray(MI->CapOperands, MI->Operands); 452 // Don't call ~MachineInstr() which must be trivial anyway because 453 // ~MachineFunction drops whole lists of MachineInstrs wihout calling their 454 // destructors. 455 InstructionRecycler.Deallocate(Allocator, MI); 456 } 457 458 /// Allocate a new MachineBasicBlock. Use this instead of 459 /// `new MachineBasicBlock'. 460 MachineBasicBlock * 461 MachineFunction::CreateMachineBasicBlock(const BasicBlock *BB, 462 std::optional<UniqueBBID> BBID) { 463 MachineBasicBlock *MBB = 464 new (BasicBlockRecycler.Allocate<MachineBasicBlock>(Allocator)) 465 MachineBasicBlock(*this, BB); 466 // Set BBID for `-basic-block=sections=labels` and 467 // `-basic-block-sections=list` to allow robust mapping of profiles to basic 468 // blocks. 469 if (Target.getBBSectionsType() == BasicBlockSection::Labels || 470 Target.Options.BBAddrMap || 471 Target.getBBSectionsType() == BasicBlockSection::List) 472 MBB->setBBID(BBID.has_value() ? *BBID : UniqueBBID{NextBBID++, 0}); 473 return MBB; 474 } 475 476 /// Delete the given MachineBasicBlock. 477 void MachineFunction::deleteMachineBasicBlock(MachineBasicBlock *MBB) { 478 assert(MBB->getParent() == this && "MBB parent mismatch!"); 479 // Clean up any references to MBB in jump tables before deleting it. 480 if (JumpTableInfo) 481 JumpTableInfo->RemoveMBBFromJumpTables(MBB); 482 MBB->~MachineBasicBlock(); 483 BasicBlockRecycler.Deallocate(Allocator, MBB); 484 } 485 486 MachineMemOperand *MachineFunction::getMachineMemOperand( 487 MachinePointerInfo PtrInfo, MachineMemOperand::Flags f, uint64_t s, 488 Align base_alignment, const AAMDNodes &AAInfo, const MDNode *Ranges, 489 SyncScope::ID SSID, AtomicOrdering Ordering, 490 AtomicOrdering FailureOrdering) { 491 return new (Allocator) 492 MachineMemOperand(PtrInfo, f, s, base_alignment, AAInfo, Ranges, 493 SSID, Ordering, FailureOrdering); 494 } 495 496 MachineMemOperand *MachineFunction::getMachineMemOperand( 497 MachinePointerInfo PtrInfo, MachineMemOperand::Flags f, LLT MemTy, 498 Align base_alignment, const AAMDNodes &AAInfo, const MDNode *Ranges, 499 SyncScope::ID SSID, AtomicOrdering Ordering, 500 AtomicOrdering FailureOrdering) { 501 return new (Allocator) 502 MachineMemOperand(PtrInfo, f, MemTy, base_alignment, AAInfo, Ranges, SSID, 503 Ordering, FailureOrdering); 504 } 505 506 MachineMemOperand *MachineFunction::getMachineMemOperand( 507 const MachineMemOperand *MMO, const MachinePointerInfo &PtrInfo, uint64_t Size) { 508 return new (Allocator) 509 MachineMemOperand(PtrInfo, MMO->getFlags(), Size, MMO->getBaseAlign(), 510 AAMDNodes(), nullptr, MMO->getSyncScopeID(), 511 MMO->getSuccessOrdering(), MMO->getFailureOrdering()); 512 } 513 514 MachineMemOperand *MachineFunction::getMachineMemOperand( 515 const MachineMemOperand *MMO, const MachinePointerInfo &PtrInfo, LLT Ty) { 516 return new (Allocator) 517 MachineMemOperand(PtrInfo, MMO->getFlags(), Ty, MMO->getBaseAlign(), 518 AAMDNodes(), nullptr, MMO->getSyncScopeID(), 519 MMO->getSuccessOrdering(), MMO->getFailureOrdering()); 520 } 521 522 MachineMemOperand * 523 MachineFunction::getMachineMemOperand(const MachineMemOperand *MMO, 524 int64_t Offset, LLT Ty) { 525 const MachinePointerInfo &PtrInfo = MMO->getPointerInfo(); 526 527 // If there is no pointer value, the offset isn't tracked so we need to adjust 528 // the base alignment. 529 Align Alignment = PtrInfo.V.isNull() 530 ? commonAlignment(MMO->getBaseAlign(), Offset) 531 : MMO->getBaseAlign(); 532 533 // Do not preserve ranges, since we don't necessarily know what the high bits 534 // are anymore. 535 return new (Allocator) MachineMemOperand( 536 PtrInfo.getWithOffset(Offset), MMO->getFlags(), Ty, Alignment, 537 MMO->getAAInfo(), nullptr, MMO->getSyncScopeID(), 538 MMO->getSuccessOrdering(), MMO->getFailureOrdering()); 539 } 540 541 MachineMemOperand * 542 MachineFunction::getMachineMemOperand(const MachineMemOperand *MMO, 543 const AAMDNodes &AAInfo) { 544 MachinePointerInfo MPI = MMO->getValue() ? 545 MachinePointerInfo(MMO->getValue(), MMO->getOffset()) : 546 MachinePointerInfo(MMO->getPseudoValue(), MMO->getOffset()); 547 548 return new (Allocator) MachineMemOperand( 549 MPI, MMO->getFlags(), MMO->getSize(), MMO->getBaseAlign(), AAInfo, 550 MMO->getRanges(), MMO->getSyncScopeID(), MMO->getSuccessOrdering(), 551 MMO->getFailureOrdering()); 552 } 553 554 MachineMemOperand * 555 MachineFunction::getMachineMemOperand(const MachineMemOperand *MMO, 556 MachineMemOperand::Flags Flags) { 557 return new (Allocator) MachineMemOperand( 558 MMO->getPointerInfo(), Flags, MMO->getSize(), MMO->getBaseAlign(), 559 MMO->getAAInfo(), MMO->getRanges(), MMO->getSyncScopeID(), 560 MMO->getSuccessOrdering(), MMO->getFailureOrdering()); 561 } 562 563 MachineInstr::ExtraInfo *MachineFunction::createMIExtraInfo( 564 ArrayRef<MachineMemOperand *> MMOs, MCSymbol *PreInstrSymbol, 565 MCSymbol *PostInstrSymbol, MDNode *HeapAllocMarker, MDNode *PCSections, 566 uint32_t CFIType) { 567 return MachineInstr::ExtraInfo::create(Allocator, MMOs, PreInstrSymbol, 568 PostInstrSymbol, HeapAllocMarker, 569 PCSections, CFIType); 570 } 571 572 const char *MachineFunction::createExternalSymbolName(StringRef Name) { 573 char *Dest = Allocator.Allocate<char>(Name.size() + 1); 574 llvm::copy(Name, Dest); 575 Dest[Name.size()] = 0; 576 return Dest; 577 } 578 579 uint32_t *MachineFunction::allocateRegMask() { 580 unsigned NumRegs = getSubtarget().getRegisterInfo()->getNumRegs(); 581 unsigned Size = MachineOperand::getRegMaskSize(NumRegs); 582 uint32_t *Mask = Allocator.Allocate<uint32_t>(Size); 583 memset(Mask, 0, Size * sizeof(Mask[0])); 584 return Mask; 585 } 586 587 ArrayRef<int> MachineFunction::allocateShuffleMask(ArrayRef<int> Mask) { 588 int* AllocMask = Allocator.Allocate<int>(Mask.size()); 589 copy(Mask, AllocMask); 590 return {AllocMask, Mask.size()}; 591 } 592 593 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP) 594 LLVM_DUMP_METHOD void MachineFunction::dump() const { 595 print(dbgs()); 596 } 597 #endif 598 599 StringRef MachineFunction::getName() const { 600 return getFunction().getName(); 601 } 602 603 void MachineFunction::print(raw_ostream &OS, const SlotIndexes *Indexes) const { 604 OS << "# Machine code for function " << getName() << ": "; 605 getProperties().print(OS); 606 OS << '\n'; 607 608 // Print Frame Information 609 FrameInfo->print(*this, OS); 610 611 // Print JumpTable Information 612 if (JumpTableInfo) 613 JumpTableInfo->print(OS); 614 615 // Print Constant Pool 616 ConstantPool->print(OS); 617 618 const TargetRegisterInfo *TRI = getSubtarget().getRegisterInfo(); 619 620 if (RegInfo && !RegInfo->livein_empty()) { 621 OS << "Function Live Ins: "; 622 for (MachineRegisterInfo::livein_iterator 623 I = RegInfo->livein_begin(), E = RegInfo->livein_end(); I != E; ++I) { 624 OS << printReg(I->first, TRI); 625 if (I->second) 626 OS << " in " << printReg(I->second, TRI); 627 if (std::next(I) != E) 628 OS << ", "; 629 } 630 OS << '\n'; 631 } 632 633 ModuleSlotTracker MST(getFunction().getParent()); 634 MST.incorporateFunction(getFunction()); 635 for (const auto &BB : *this) { 636 OS << '\n'; 637 // If we print the whole function, print it at its most verbose level. 638 BB.print(OS, MST, Indexes, /*IsStandalone=*/true); 639 } 640 641 OS << "\n# End machine code for function " << getName() << ".\n\n"; 642 } 643 644 /// True if this function needs frame moves for debug or exceptions. 645 bool MachineFunction::needsFrameMoves() const { 646 return getMMI().hasDebugInfo() || 647 getTarget().Options.ForceDwarfFrameSection || 648 F.needsUnwindTableEntry(); 649 } 650 651 namespace llvm { 652 653 template<> 654 struct DOTGraphTraits<const MachineFunction*> : public DefaultDOTGraphTraits { 655 DOTGraphTraits(bool isSimple = false) : DefaultDOTGraphTraits(isSimple) {} 656 657 static std::string getGraphName(const MachineFunction *F) { 658 return ("CFG for '" + F->getName() + "' function").str(); 659 } 660 661 std::string getNodeLabel(const MachineBasicBlock *Node, 662 const MachineFunction *Graph) { 663 std::string OutStr; 664 { 665 raw_string_ostream OSS(OutStr); 666 667 if (isSimple()) { 668 OSS << printMBBReference(*Node); 669 if (const BasicBlock *BB = Node->getBasicBlock()) 670 OSS << ": " << BB->getName(); 671 } else 672 Node->print(OSS); 673 } 674 675 if (OutStr[0] == '\n') OutStr.erase(OutStr.begin()); 676 677 // Process string output to make it nicer... 678 for (unsigned i = 0; i != OutStr.length(); ++i) 679 if (OutStr[i] == '\n') { // Left justify 680 OutStr[i] = '\\'; 681 OutStr.insert(OutStr.begin()+i+1, 'l'); 682 } 683 return OutStr; 684 } 685 }; 686 687 } // end namespace llvm 688 689 void MachineFunction::viewCFG() const 690 { 691 #ifndef NDEBUG 692 ViewGraph(this, "mf" + getName()); 693 #else 694 errs() << "MachineFunction::viewCFG is only available in debug builds on " 695 << "systems with Graphviz or gv!\n"; 696 #endif // NDEBUG 697 } 698 699 void MachineFunction::viewCFGOnly() const 700 { 701 #ifndef NDEBUG 702 ViewGraph(this, "mf" + getName(), true); 703 #else 704 errs() << "MachineFunction::viewCFGOnly is only available in debug builds on " 705 << "systems with Graphviz or gv!\n"; 706 #endif // NDEBUG 707 } 708 709 /// Add the specified physical register as a live-in value and 710 /// create a corresponding virtual register for it. 711 Register MachineFunction::addLiveIn(MCRegister PReg, 712 const TargetRegisterClass *RC) { 713 MachineRegisterInfo &MRI = getRegInfo(); 714 Register VReg = MRI.getLiveInVirtReg(PReg); 715 if (VReg) { 716 const TargetRegisterClass *VRegRC = MRI.getRegClass(VReg); 717 (void)VRegRC; 718 // A physical register can be added several times. 719 // Between two calls, the register class of the related virtual register 720 // may have been constrained to match some operation constraints. 721 // In that case, check that the current register class includes the 722 // physical register and is a sub class of the specified RC. 723 assert((VRegRC == RC || (VRegRC->contains(PReg) && 724 RC->hasSubClassEq(VRegRC))) && 725 "Register class mismatch!"); 726 return VReg; 727 } 728 VReg = MRI.createVirtualRegister(RC); 729 MRI.addLiveIn(PReg, VReg); 730 return VReg; 731 } 732 733 /// Return the MCSymbol for the specified non-empty jump table. 734 /// If isLinkerPrivate is specified, an 'l' label is returned, otherwise a 735 /// normal 'L' label is returned. 736 MCSymbol *MachineFunction::getJTISymbol(unsigned JTI, MCContext &Ctx, 737 bool isLinkerPrivate) const { 738 const DataLayout &DL = getDataLayout(); 739 assert(JumpTableInfo && "No jump tables"); 740 assert(JTI < JumpTableInfo->getJumpTables().size() && "Invalid JTI!"); 741 742 StringRef Prefix = isLinkerPrivate ? DL.getLinkerPrivateGlobalPrefix() 743 : DL.getPrivateGlobalPrefix(); 744 SmallString<60> Name; 745 raw_svector_ostream(Name) 746 << Prefix << "JTI" << getFunctionNumber() << '_' << JTI; 747 return Ctx.getOrCreateSymbol(Name); 748 } 749 750 /// Return a function-local symbol to represent the PIC base. 751 MCSymbol *MachineFunction::getPICBaseSymbol() const { 752 const DataLayout &DL = getDataLayout(); 753 return Ctx.getOrCreateSymbol(Twine(DL.getPrivateGlobalPrefix()) + 754 Twine(getFunctionNumber()) + "$pb"); 755 } 756 757 /// \name Exception Handling 758 /// \{ 759 760 LandingPadInfo & 761 MachineFunction::getOrCreateLandingPadInfo(MachineBasicBlock *LandingPad) { 762 unsigned N = LandingPads.size(); 763 for (unsigned i = 0; i < N; ++i) { 764 LandingPadInfo &LP = LandingPads[i]; 765 if (LP.LandingPadBlock == LandingPad) 766 return LP; 767 } 768 769 LandingPads.push_back(LandingPadInfo(LandingPad)); 770 return LandingPads[N]; 771 } 772 773 void MachineFunction::addInvoke(MachineBasicBlock *LandingPad, 774 MCSymbol *BeginLabel, MCSymbol *EndLabel) { 775 LandingPadInfo &LP = getOrCreateLandingPadInfo(LandingPad); 776 LP.BeginLabels.push_back(BeginLabel); 777 LP.EndLabels.push_back(EndLabel); 778 } 779 780 MCSymbol *MachineFunction::addLandingPad(MachineBasicBlock *LandingPad) { 781 MCSymbol *LandingPadLabel = Ctx.createTempSymbol(); 782 LandingPadInfo &LP = getOrCreateLandingPadInfo(LandingPad); 783 LP.LandingPadLabel = LandingPadLabel; 784 785 const Instruction *FirstI = LandingPad->getBasicBlock()->getFirstNonPHI(); 786 if (const auto *LPI = dyn_cast<LandingPadInst>(FirstI)) { 787 // If there's no typeid list specified, then "cleanup" is implicit. 788 // Otherwise, id 0 is reserved for the cleanup action. 789 if (LPI->isCleanup() && LPI->getNumClauses() != 0) 790 LP.TypeIds.push_back(0); 791 792 // FIXME: New EH - Add the clauses in reverse order. This isn't 100% 793 // correct, but we need to do it this way because of how the DWARF EH 794 // emitter processes the clauses. 795 for (unsigned I = LPI->getNumClauses(); I != 0; --I) { 796 Value *Val = LPI->getClause(I - 1); 797 if (LPI->isCatch(I - 1)) { 798 LP.TypeIds.push_back( 799 getTypeIDFor(dyn_cast<GlobalValue>(Val->stripPointerCasts()))); 800 } else { 801 // Add filters in a list. 802 auto *CVal = cast<Constant>(Val); 803 SmallVector<unsigned, 4> FilterList; 804 for (const Use &U : CVal->operands()) 805 FilterList.push_back( 806 getTypeIDFor(cast<GlobalValue>(U->stripPointerCasts()))); 807 808 LP.TypeIds.push_back(getFilterIDFor(FilterList)); 809 } 810 } 811 812 } else if (const auto *CPI = dyn_cast<CatchPadInst>(FirstI)) { 813 for (unsigned I = CPI->arg_size(); I != 0; --I) { 814 auto *TypeInfo = 815 dyn_cast<GlobalValue>(CPI->getArgOperand(I - 1)->stripPointerCasts()); 816 LP.TypeIds.push_back(getTypeIDFor(TypeInfo)); 817 } 818 819 } else { 820 assert(isa<CleanupPadInst>(FirstI) && "Invalid landingpad!"); 821 } 822 823 return LandingPadLabel; 824 } 825 826 void MachineFunction::setCallSiteLandingPad(MCSymbol *Sym, 827 ArrayRef<unsigned> Sites) { 828 LPadToCallSiteMap[Sym].append(Sites.begin(), Sites.end()); 829 } 830 831 unsigned MachineFunction::getTypeIDFor(const GlobalValue *TI) { 832 for (unsigned i = 0, N = TypeInfos.size(); i != N; ++i) 833 if (TypeInfos[i] == TI) return i + 1; 834 835 TypeInfos.push_back(TI); 836 return TypeInfos.size(); 837 } 838 839 int MachineFunction::getFilterIDFor(ArrayRef<unsigned> TyIds) { 840 // If the new filter coincides with the tail of an existing filter, then 841 // re-use the existing filter. Folding filters more than this requires 842 // re-ordering filters and/or their elements - probably not worth it. 843 for (unsigned i : FilterEnds) { 844 unsigned j = TyIds.size(); 845 846 while (i && j) 847 if (FilterIds[--i] != TyIds[--j]) 848 goto try_next; 849 850 if (!j) 851 // The new filter coincides with range [i, end) of the existing filter. 852 return -(1 + i); 853 854 try_next:; 855 } 856 857 // Add the new filter. 858 int FilterID = -(1 + FilterIds.size()); 859 FilterIds.reserve(FilterIds.size() + TyIds.size() + 1); 860 llvm::append_range(FilterIds, TyIds); 861 FilterEnds.push_back(FilterIds.size()); 862 FilterIds.push_back(0); // terminator 863 return FilterID; 864 } 865 866 MachineFunction::CallSiteInfoMap::iterator 867 MachineFunction::getCallSiteInfo(const MachineInstr *MI) { 868 assert(MI->isCandidateForCallSiteEntry() && 869 "Call site info refers only to call (MI) candidates"); 870 871 if (!Target.Options.EmitCallSiteInfo) 872 return CallSitesInfo.end(); 873 return CallSitesInfo.find(MI); 874 } 875 876 /// Return the call machine instruction or find a call within bundle. 877 static const MachineInstr *getCallInstr(const MachineInstr *MI) { 878 if (!MI->isBundle()) 879 return MI; 880 881 for (const auto &BMI : make_range(getBundleStart(MI->getIterator()), 882 getBundleEnd(MI->getIterator()))) 883 if (BMI.isCandidateForCallSiteEntry()) 884 return &BMI; 885 886 llvm_unreachable("Unexpected bundle without a call site candidate"); 887 } 888 889 void MachineFunction::eraseCallSiteInfo(const MachineInstr *MI) { 890 assert(MI->shouldUpdateCallSiteInfo() && 891 "Call site info refers only to call (MI) candidates or " 892 "candidates inside bundles"); 893 894 const MachineInstr *CallMI = getCallInstr(MI); 895 CallSiteInfoMap::iterator CSIt = getCallSiteInfo(CallMI); 896 if (CSIt == CallSitesInfo.end()) 897 return; 898 CallSitesInfo.erase(CSIt); 899 } 900 901 void MachineFunction::copyCallSiteInfo(const MachineInstr *Old, 902 const MachineInstr *New) { 903 assert(Old->shouldUpdateCallSiteInfo() && 904 "Call site info refers only to call (MI) candidates or " 905 "candidates inside bundles"); 906 907 if (!New->isCandidateForCallSiteEntry()) 908 return eraseCallSiteInfo(Old); 909 910 const MachineInstr *OldCallMI = getCallInstr(Old); 911 CallSiteInfoMap::iterator CSIt = getCallSiteInfo(OldCallMI); 912 if (CSIt == CallSitesInfo.end()) 913 return; 914 915 CallSiteInfo CSInfo = CSIt->second; 916 CallSitesInfo[New] = CSInfo; 917 } 918 919 void MachineFunction::moveCallSiteInfo(const MachineInstr *Old, 920 const MachineInstr *New) { 921 assert(Old->shouldUpdateCallSiteInfo() && 922 "Call site info refers only to call (MI) candidates or " 923 "candidates inside bundles"); 924 925 if (!New->isCandidateForCallSiteEntry()) 926 return eraseCallSiteInfo(Old); 927 928 const MachineInstr *OldCallMI = getCallInstr(Old); 929 CallSiteInfoMap::iterator CSIt = getCallSiteInfo(OldCallMI); 930 if (CSIt == CallSitesInfo.end()) 931 return; 932 933 CallSiteInfo CSInfo = std::move(CSIt->second); 934 CallSitesInfo.erase(CSIt); 935 CallSitesInfo[New] = CSInfo; 936 } 937 938 void MachineFunction::setDebugInstrNumberingCount(unsigned Num) { 939 DebugInstrNumberingCount = Num; 940 } 941 942 void MachineFunction::makeDebugValueSubstitution(DebugInstrOperandPair A, 943 DebugInstrOperandPair B, 944 unsigned Subreg) { 945 // Catch any accidental self-loops. 946 assert(A.first != B.first); 947 // Don't allow any substitutions _from_ the memory operand number. 948 assert(A.second != DebugOperandMemNumber); 949 950 DebugValueSubstitutions.push_back({A, B, Subreg}); 951 } 952 953 void MachineFunction::substituteDebugValuesForInst(const MachineInstr &Old, 954 MachineInstr &New, 955 unsigned MaxOperand) { 956 // If the Old instruction wasn't tracked at all, there is no work to do. 957 unsigned OldInstrNum = Old.peekDebugInstrNum(); 958 if (!OldInstrNum) 959 return; 960 961 // Iterate over all operands looking for defs to create substitutions for. 962 // Avoid creating new instr numbers unless we create a new substitution. 963 // While this has no functional effect, it risks confusing someone reading 964 // MIR output. 965 // Examine all the operands, or the first N specified by the caller. 966 MaxOperand = std::min(MaxOperand, Old.getNumOperands()); 967 for (unsigned int I = 0; I < MaxOperand; ++I) { 968 const auto &OldMO = Old.getOperand(I); 969 auto &NewMO = New.getOperand(I); 970 (void)NewMO; 971 972 if (!OldMO.isReg() || !OldMO.isDef()) 973 continue; 974 assert(NewMO.isDef()); 975 976 unsigned NewInstrNum = New.getDebugInstrNum(); 977 makeDebugValueSubstitution(std::make_pair(OldInstrNum, I), 978 std::make_pair(NewInstrNum, I)); 979 } 980 } 981 982 auto MachineFunction::salvageCopySSA( 983 MachineInstr &MI, DenseMap<Register, DebugInstrOperandPair> &DbgPHICache) 984 -> DebugInstrOperandPair { 985 const TargetInstrInfo &TII = *getSubtarget().getInstrInfo(); 986 987 // Check whether this copy-like instruction has already been salvaged into 988 // an operand pair. 989 Register Dest; 990 if (auto CopyDstSrc = TII.isCopyInstr(MI)) { 991 Dest = CopyDstSrc->Destination->getReg(); 992 } else { 993 assert(MI.isSubregToReg()); 994 Dest = MI.getOperand(0).getReg(); 995 } 996 997 auto CacheIt = DbgPHICache.find(Dest); 998 if (CacheIt != DbgPHICache.end()) 999 return CacheIt->second; 1000 1001 // Calculate the instruction number to use, or install a DBG_PHI. 1002 auto OperandPair = salvageCopySSAImpl(MI); 1003 DbgPHICache.insert({Dest, OperandPair}); 1004 return OperandPair; 1005 } 1006 1007 auto MachineFunction::salvageCopySSAImpl(MachineInstr &MI) 1008 -> DebugInstrOperandPair { 1009 MachineRegisterInfo &MRI = getRegInfo(); 1010 const TargetRegisterInfo &TRI = *MRI.getTargetRegisterInfo(); 1011 const TargetInstrInfo &TII = *getSubtarget().getInstrInfo(); 1012 1013 // Chase the value read by a copy-like instruction back to the instruction 1014 // that ultimately _defines_ that value. This may pass: 1015 // * Through multiple intermediate copies, including subregister moves / 1016 // copies, 1017 // * Copies from physical registers that must then be traced back to the 1018 // defining instruction, 1019 // * Or, physical registers may be live-in to (only) the entry block, which 1020 // requires a DBG_PHI to be created. 1021 // We can pursue this problem in that order: trace back through copies, 1022 // optionally through a physical register, to a defining instruction. We 1023 // should never move from physreg to vreg. As we're still in SSA form, no need 1024 // to worry about partial definitions of registers. 1025 1026 // Helper lambda to interpret a copy-like instruction. Takes instruction, 1027 // returns the register read and any subregister identifying which part is 1028 // read. 1029 auto GetRegAndSubreg = 1030 [&](const MachineInstr &Cpy) -> std::pair<Register, unsigned> { 1031 Register NewReg, OldReg; 1032 unsigned SubReg; 1033 if (Cpy.isCopy()) { 1034 OldReg = Cpy.getOperand(0).getReg(); 1035 NewReg = Cpy.getOperand(1).getReg(); 1036 SubReg = Cpy.getOperand(1).getSubReg(); 1037 } else if (Cpy.isSubregToReg()) { 1038 OldReg = Cpy.getOperand(0).getReg(); 1039 NewReg = Cpy.getOperand(2).getReg(); 1040 SubReg = Cpy.getOperand(3).getImm(); 1041 } else { 1042 auto CopyDetails = *TII.isCopyInstr(Cpy); 1043 const MachineOperand &Src = *CopyDetails.Source; 1044 const MachineOperand &Dest = *CopyDetails.Destination; 1045 OldReg = Dest.getReg(); 1046 NewReg = Src.getReg(); 1047 SubReg = Src.getSubReg(); 1048 } 1049 1050 return {NewReg, SubReg}; 1051 }; 1052 1053 // First seek either the defining instruction, or a copy from a physreg. 1054 // During search, the current state is the current copy instruction, and which 1055 // register we've read. Accumulate qualifying subregisters into SubregsSeen; 1056 // deal with those later. 1057 auto State = GetRegAndSubreg(MI); 1058 auto CurInst = MI.getIterator(); 1059 SmallVector<unsigned, 4> SubregsSeen; 1060 while (true) { 1061 // If we've found a copy from a physreg, first portion of search is over. 1062 if (!State.first.isVirtual()) 1063 break; 1064 1065 // Record any subregister qualifier. 1066 if (State.second) 1067 SubregsSeen.push_back(State.second); 1068 1069 assert(MRI.hasOneDef(State.first)); 1070 MachineInstr &Inst = *MRI.def_begin(State.first)->getParent(); 1071 CurInst = Inst.getIterator(); 1072 1073 // Any non-copy instruction is the defining instruction we're seeking. 1074 if (!Inst.isCopyLike() && !TII.isCopyInstr(Inst)) 1075 break; 1076 State = GetRegAndSubreg(Inst); 1077 }; 1078 1079 // Helper lambda to apply additional subregister substitutions to a known 1080 // instruction/operand pair. Adds new (fake) substitutions so that we can 1081 // record the subregister. FIXME: this isn't very space efficient if multiple 1082 // values are tracked back through the same copies; cache something later. 1083 auto ApplySubregisters = 1084 [&](DebugInstrOperandPair P) -> DebugInstrOperandPair { 1085 for (unsigned Subreg : reverse(SubregsSeen)) { 1086 // Fetch a new instruction number, not attached to an actual instruction. 1087 unsigned NewInstrNumber = getNewDebugInstrNum(); 1088 // Add a substitution from the "new" number to the known one, with a 1089 // qualifying subreg. 1090 makeDebugValueSubstitution({NewInstrNumber, 0}, P, Subreg); 1091 // Return the new number; to find the underlying value, consumers need to 1092 // deal with the qualifying subreg. 1093 P = {NewInstrNumber, 0}; 1094 } 1095 return P; 1096 }; 1097 1098 // If we managed to find the defining instruction after COPYs, return an 1099 // instruction / operand pair after adding subregister qualifiers. 1100 if (State.first.isVirtual()) { 1101 // Virtual register def -- we can just look up where this happens. 1102 MachineInstr *Inst = MRI.def_begin(State.first)->getParent(); 1103 for (auto &MO : Inst->all_defs()) { 1104 if (MO.getReg() != State.first) 1105 continue; 1106 return ApplySubregisters({Inst->getDebugInstrNum(), MO.getOperandNo()}); 1107 } 1108 1109 llvm_unreachable("Vreg def with no corresponding operand?"); 1110 } 1111 1112 // Our search ended in a copy from a physreg: walk back up the function 1113 // looking for whatever defines the physreg. 1114 assert(CurInst->isCopyLike() || TII.isCopyInstr(*CurInst)); 1115 State = GetRegAndSubreg(*CurInst); 1116 Register RegToSeek = State.first; 1117 1118 auto RMII = CurInst->getReverseIterator(); 1119 auto PrevInstrs = make_range(RMII, CurInst->getParent()->instr_rend()); 1120 for (auto &ToExamine : PrevInstrs) { 1121 for (auto &MO : ToExamine.all_defs()) { 1122 // Test for operand that defines something aliasing RegToSeek. 1123 if (!TRI.regsOverlap(RegToSeek, MO.getReg())) 1124 continue; 1125 1126 return ApplySubregisters( 1127 {ToExamine.getDebugInstrNum(), MO.getOperandNo()}); 1128 } 1129 } 1130 1131 MachineBasicBlock &InsertBB = *CurInst->getParent(); 1132 1133 // We reached the start of the block before finding a defining instruction. 1134 // There are numerous scenarios where this can happen: 1135 // * Constant physical registers, 1136 // * Several intrinsics that allow LLVM-IR to read arbitary registers, 1137 // * Arguments in the entry block, 1138 // * Exception handling landing pads. 1139 // Validating all of them is too difficult, so just insert a DBG_PHI reading 1140 // the variable value at this position, rather than checking it makes sense. 1141 1142 // Create DBG_PHI for specified physreg. 1143 auto Builder = BuildMI(InsertBB, InsertBB.getFirstNonPHI(), DebugLoc(), 1144 TII.get(TargetOpcode::DBG_PHI)); 1145 Builder.addReg(State.first); 1146 unsigned NewNum = getNewDebugInstrNum(); 1147 Builder.addImm(NewNum); 1148 return ApplySubregisters({NewNum, 0u}); 1149 } 1150 1151 void MachineFunction::finalizeDebugInstrRefs() { 1152 auto *TII = getSubtarget().getInstrInfo(); 1153 1154 auto MakeUndefDbgValue = [&](MachineInstr &MI) { 1155 const MCInstrDesc &RefII = TII->get(TargetOpcode::DBG_VALUE_LIST); 1156 MI.setDesc(RefII); 1157 MI.setDebugValueUndef(); 1158 }; 1159 1160 DenseMap<Register, DebugInstrOperandPair> ArgDbgPHIs; 1161 for (auto &MBB : *this) { 1162 for (auto &MI : MBB) { 1163 if (!MI.isDebugRef()) 1164 continue; 1165 1166 bool IsValidRef = true; 1167 1168 for (MachineOperand &MO : MI.debug_operands()) { 1169 if (!MO.isReg()) 1170 continue; 1171 1172 Register Reg = MO.getReg(); 1173 1174 // Some vregs can be deleted as redundant in the meantime. Mark those 1175 // as DBG_VALUE $noreg. Additionally, some normal instructions are 1176 // quickly deleted, leaving dangling references to vregs with no def. 1177 if (Reg == 0 || !RegInfo->hasOneDef(Reg)) { 1178 IsValidRef = false; 1179 break; 1180 } 1181 1182 assert(Reg.isVirtual()); 1183 MachineInstr &DefMI = *RegInfo->def_instr_begin(Reg); 1184 1185 // If we've found a copy-like instruction, follow it back to the 1186 // instruction that defines the source value, see salvageCopySSA docs 1187 // for why this is important. 1188 if (DefMI.isCopyLike() || TII->isCopyInstr(DefMI)) { 1189 auto Result = salvageCopySSA(DefMI, ArgDbgPHIs); 1190 MO.ChangeToDbgInstrRef(Result.first, Result.second); 1191 } else { 1192 // Otherwise, identify the operand number that the VReg refers to. 1193 unsigned OperandIdx = 0; 1194 for (const auto &DefMO : DefMI.operands()) { 1195 if (DefMO.isReg() && DefMO.isDef() && DefMO.getReg() == Reg) 1196 break; 1197 ++OperandIdx; 1198 } 1199 assert(OperandIdx < DefMI.getNumOperands()); 1200 1201 // Morph this instr ref to point at the given instruction and operand. 1202 unsigned ID = DefMI.getDebugInstrNum(); 1203 MO.ChangeToDbgInstrRef(ID, OperandIdx); 1204 } 1205 } 1206 1207 if (!IsValidRef) 1208 MakeUndefDbgValue(MI); 1209 } 1210 } 1211 } 1212 1213 bool MachineFunction::shouldUseDebugInstrRef() const { 1214 // Disable instr-ref at -O0: it's very slow (in compile time). We can still 1215 // have optimized code inlined into this unoptimized code, however with 1216 // fewer and less aggressive optimizations happening, coverage and accuracy 1217 // should not suffer. 1218 if (getTarget().getOptLevel() == CodeGenOptLevel::None) 1219 return false; 1220 1221 // Don't use instr-ref if this function is marked optnone. 1222 if (F.hasFnAttribute(Attribute::OptimizeNone)) 1223 return false; 1224 1225 if (llvm::debuginfoShouldUseDebugInstrRef(getTarget().getTargetTriple())) 1226 return true; 1227 1228 return false; 1229 } 1230 1231 bool MachineFunction::useDebugInstrRef() const { 1232 return UseDebugInstrRef; 1233 } 1234 1235 void MachineFunction::setUseDebugInstrRef(bool Use) { 1236 UseDebugInstrRef = Use; 1237 } 1238 1239 // Use one million as a high / reserved number. 1240 const unsigned MachineFunction::DebugOperandMemNumber = 1000000; 1241 1242 /// \} 1243 1244 //===----------------------------------------------------------------------===// 1245 // MachineJumpTableInfo implementation 1246 //===----------------------------------------------------------------------===// 1247 1248 /// Return the size of each entry in the jump table. 1249 unsigned MachineJumpTableInfo::getEntrySize(const DataLayout &TD) const { 1250 // The size of a jump table entry is 4 bytes unless the entry is just the 1251 // address of a block, in which case it is the pointer size. 1252 switch (getEntryKind()) { 1253 case MachineJumpTableInfo::EK_BlockAddress: 1254 return TD.getPointerSize(); 1255 case MachineJumpTableInfo::EK_GPRel64BlockAddress: 1256 case MachineJumpTableInfo::EK_LabelDifference64: 1257 return 8; 1258 case MachineJumpTableInfo::EK_GPRel32BlockAddress: 1259 case MachineJumpTableInfo::EK_LabelDifference32: 1260 case MachineJumpTableInfo::EK_Custom32: 1261 return 4; 1262 case MachineJumpTableInfo::EK_Inline: 1263 return 0; 1264 } 1265 llvm_unreachable("Unknown jump table encoding!"); 1266 } 1267 1268 /// Return the alignment of each entry in the jump table. 1269 unsigned MachineJumpTableInfo::getEntryAlignment(const DataLayout &TD) const { 1270 // The alignment of a jump table entry is the alignment of int32 unless the 1271 // entry is just the address of a block, in which case it is the pointer 1272 // alignment. 1273 switch (getEntryKind()) { 1274 case MachineJumpTableInfo::EK_BlockAddress: 1275 return TD.getPointerABIAlignment(0).value(); 1276 case MachineJumpTableInfo::EK_GPRel64BlockAddress: 1277 case MachineJumpTableInfo::EK_LabelDifference64: 1278 return TD.getABIIntegerTypeAlignment(64).value(); 1279 case MachineJumpTableInfo::EK_GPRel32BlockAddress: 1280 case MachineJumpTableInfo::EK_LabelDifference32: 1281 case MachineJumpTableInfo::EK_Custom32: 1282 return TD.getABIIntegerTypeAlignment(32).value(); 1283 case MachineJumpTableInfo::EK_Inline: 1284 return 1; 1285 } 1286 llvm_unreachable("Unknown jump table encoding!"); 1287 } 1288 1289 /// Create a new jump table entry in the jump table info. 1290 unsigned MachineJumpTableInfo::createJumpTableIndex( 1291 const std::vector<MachineBasicBlock*> &DestBBs) { 1292 assert(!DestBBs.empty() && "Cannot create an empty jump table!"); 1293 JumpTables.push_back(MachineJumpTableEntry(DestBBs)); 1294 return JumpTables.size()-1; 1295 } 1296 1297 /// If Old is the target of any jump tables, update the jump tables to branch 1298 /// to New instead. 1299 bool MachineJumpTableInfo::ReplaceMBBInJumpTables(MachineBasicBlock *Old, 1300 MachineBasicBlock *New) { 1301 assert(Old != New && "Not making a change?"); 1302 bool MadeChange = false; 1303 for (size_t i = 0, e = JumpTables.size(); i != e; ++i) 1304 ReplaceMBBInJumpTable(i, Old, New); 1305 return MadeChange; 1306 } 1307 1308 /// If MBB is present in any jump tables, remove it. 1309 bool MachineJumpTableInfo::RemoveMBBFromJumpTables(MachineBasicBlock *MBB) { 1310 bool MadeChange = false; 1311 for (MachineJumpTableEntry &JTE : JumpTables) { 1312 auto removeBeginItr = std::remove(JTE.MBBs.begin(), JTE.MBBs.end(), MBB); 1313 MadeChange |= (removeBeginItr != JTE.MBBs.end()); 1314 JTE.MBBs.erase(removeBeginItr, JTE.MBBs.end()); 1315 } 1316 return MadeChange; 1317 } 1318 1319 /// If Old is a target of the jump tables, update the jump table to branch to 1320 /// New instead. 1321 bool MachineJumpTableInfo::ReplaceMBBInJumpTable(unsigned Idx, 1322 MachineBasicBlock *Old, 1323 MachineBasicBlock *New) { 1324 assert(Old != New && "Not making a change?"); 1325 bool MadeChange = false; 1326 MachineJumpTableEntry &JTE = JumpTables[Idx]; 1327 for (MachineBasicBlock *&MBB : JTE.MBBs) 1328 if (MBB == Old) { 1329 MBB = New; 1330 MadeChange = true; 1331 } 1332 return MadeChange; 1333 } 1334 1335 void MachineJumpTableInfo::print(raw_ostream &OS) const { 1336 if (JumpTables.empty()) return; 1337 1338 OS << "Jump Tables:\n"; 1339 1340 for (unsigned i = 0, e = JumpTables.size(); i != e; ++i) { 1341 OS << printJumpTableEntryReference(i) << ':'; 1342 for (const MachineBasicBlock *MBB : JumpTables[i].MBBs) 1343 OS << ' ' << printMBBReference(*MBB); 1344 if (i != e) 1345 OS << '\n'; 1346 } 1347 1348 OS << '\n'; 1349 } 1350 1351 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP) 1352 LLVM_DUMP_METHOD void MachineJumpTableInfo::dump() const { print(dbgs()); } 1353 #endif 1354 1355 Printable llvm::printJumpTableEntryReference(unsigned Idx) { 1356 return Printable([Idx](raw_ostream &OS) { OS << "%jump-table." << Idx; }); 1357 } 1358 1359 //===----------------------------------------------------------------------===// 1360 // MachineConstantPool implementation 1361 //===----------------------------------------------------------------------===// 1362 1363 void MachineConstantPoolValue::anchor() {} 1364 1365 unsigned MachineConstantPoolValue::getSizeInBytes(const DataLayout &DL) const { 1366 return DL.getTypeAllocSize(Ty); 1367 } 1368 1369 unsigned MachineConstantPoolEntry::getSizeInBytes(const DataLayout &DL) const { 1370 if (isMachineConstantPoolEntry()) 1371 return Val.MachineCPVal->getSizeInBytes(DL); 1372 return DL.getTypeAllocSize(Val.ConstVal->getType()); 1373 } 1374 1375 bool MachineConstantPoolEntry::needsRelocation() const { 1376 if (isMachineConstantPoolEntry()) 1377 return true; 1378 return Val.ConstVal->needsDynamicRelocation(); 1379 } 1380 1381 SectionKind 1382 MachineConstantPoolEntry::getSectionKind(const DataLayout *DL) const { 1383 if (needsRelocation()) 1384 return SectionKind::getReadOnlyWithRel(); 1385 switch (getSizeInBytes(*DL)) { 1386 case 4: 1387 return SectionKind::getMergeableConst4(); 1388 case 8: 1389 return SectionKind::getMergeableConst8(); 1390 case 16: 1391 return SectionKind::getMergeableConst16(); 1392 case 32: 1393 return SectionKind::getMergeableConst32(); 1394 default: 1395 return SectionKind::getReadOnly(); 1396 } 1397 } 1398 1399 MachineConstantPool::~MachineConstantPool() { 1400 // A constant may be a member of both Constants and MachineCPVsSharingEntries, 1401 // so keep track of which we've deleted to avoid double deletions. 1402 DenseSet<MachineConstantPoolValue*> Deleted; 1403 for (const MachineConstantPoolEntry &C : Constants) 1404 if (C.isMachineConstantPoolEntry()) { 1405 Deleted.insert(C.Val.MachineCPVal); 1406 delete C.Val.MachineCPVal; 1407 } 1408 for (MachineConstantPoolValue *CPV : MachineCPVsSharingEntries) { 1409 if (Deleted.count(CPV) == 0) 1410 delete CPV; 1411 } 1412 } 1413 1414 /// Test whether the given two constants can be allocated the same constant pool 1415 /// entry referenced by \param A. 1416 static bool CanShareConstantPoolEntry(const Constant *A, const Constant *B, 1417 const DataLayout &DL) { 1418 // Handle the trivial case quickly. 1419 if (A == B) return true; 1420 1421 // If they have the same type but weren't the same constant, quickly 1422 // reject them. 1423 if (A->getType() == B->getType()) return false; 1424 1425 // We can't handle structs or arrays. 1426 if (isa<StructType>(A->getType()) || isa<ArrayType>(A->getType()) || 1427 isa<StructType>(B->getType()) || isa<ArrayType>(B->getType())) 1428 return false; 1429 1430 // For now, only support constants with the same size. 1431 uint64_t StoreSize = DL.getTypeStoreSize(A->getType()); 1432 if (StoreSize != DL.getTypeStoreSize(B->getType()) || StoreSize > 128) 1433 return false; 1434 1435 bool ContainsUndefOrPoisonA = A->containsUndefOrPoisonElement(); 1436 1437 Type *IntTy = IntegerType::get(A->getContext(), StoreSize*8); 1438 1439 // Try constant folding a bitcast of both instructions to an integer. If we 1440 // get two identical ConstantInt's, then we are good to share them. We use 1441 // the constant folding APIs to do this so that we get the benefit of 1442 // DataLayout. 1443 if (isa<PointerType>(A->getType())) 1444 A = ConstantFoldCastOperand(Instruction::PtrToInt, 1445 const_cast<Constant *>(A), IntTy, DL); 1446 else if (A->getType() != IntTy) 1447 A = ConstantFoldCastOperand(Instruction::BitCast, const_cast<Constant *>(A), 1448 IntTy, DL); 1449 if (isa<PointerType>(B->getType())) 1450 B = ConstantFoldCastOperand(Instruction::PtrToInt, 1451 const_cast<Constant *>(B), IntTy, DL); 1452 else if (B->getType() != IntTy) 1453 B = ConstantFoldCastOperand(Instruction::BitCast, const_cast<Constant *>(B), 1454 IntTy, DL); 1455 1456 if (A != B) 1457 return false; 1458 1459 // Constants only safely match if A doesn't contain undef/poison. 1460 // As we'll be reusing A, it doesn't matter if B contain undef/poison. 1461 // TODO: Handle cases where A and B have the same undef/poison elements. 1462 // TODO: Merge A and B with mismatching undef/poison elements. 1463 return !ContainsUndefOrPoisonA; 1464 } 1465 1466 /// Create a new entry in the constant pool or return an existing one. 1467 /// User must specify the log2 of the minimum required alignment for the object. 1468 unsigned MachineConstantPool::getConstantPoolIndex(const Constant *C, 1469 Align Alignment) { 1470 if (Alignment > PoolAlignment) PoolAlignment = Alignment; 1471 1472 // Check to see if we already have this constant. 1473 // 1474 // FIXME, this could be made much more efficient for large constant pools. 1475 for (unsigned i = 0, e = Constants.size(); i != e; ++i) 1476 if (!Constants[i].isMachineConstantPoolEntry() && 1477 CanShareConstantPoolEntry(Constants[i].Val.ConstVal, C, DL)) { 1478 if (Constants[i].getAlign() < Alignment) 1479 Constants[i].Alignment = Alignment; 1480 return i; 1481 } 1482 1483 Constants.push_back(MachineConstantPoolEntry(C, Alignment)); 1484 return Constants.size()-1; 1485 } 1486 1487 unsigned MachineConstantPool::getConstantPoolIndex(MachineConstantPoolValue *V, 1488 Align Alignment) { 1489 if (Alignment > PoolAlignment) PoolAlignment = Alignment; 1490 1491 // Check to see if we already have this constant. 1492 // 1493 // FIXME, this could be made much more efficient for large constant pools. 1494 int Idx = V->getExistingMachineCPValue(this, Alignment); 1495 if (Idx != -1) { 1496 MachineCPVsSharingEntries.insert(V); 1497 return (unsigned)Idx; 1498 } 1499 1500 Constants.push_back(MachineConstantPoolEntry(V, Alignment)); 1501 return Constants.size()-1; 1502 } 1503 1504 void MachineConstantPool::print(raw_ostream &OS) const { 1505 if (Constants.empty()) return; 1506 1507 OS << "Constant Pool:\n"; 1508 for (unsigned i = 0, e = Constants.size(); i != e; ++i) { 1509 OS << " cp#" << i << ": "; 1510 if (Constants[i].isMachineConstantPoolEntry()) 1511 Constants[i].Val.MachineCPVal->print(OS); 1512 else 1513 Constants[i].Val.ConstVal->printAsOperand(OS, /*PrintType=*/false); 1514 OS << ", align=" << Constants[i].getAlign().value(); 1515 OS << "\n"; 1516 } 1517 } 1518 1519 //===----------------------------------------------------------------------===// 1520 // Template specialization for MachineFunction implementation of 1521 // ProfileSummaryInfo::getEntryCount(). 1522 //===----------------------------------------------------------------------===// 1523 template <> 1524 std::optional<Function::ProfileCount> 1525 ProfileSummaryInfo::getEntryCount<llvm::MachineFunction>( 1526 const llvm::MachineFunction *F) const { 1527 return F->getFunction().getEntryCount(); 1528 } 1529 1530 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP) 1531 LLVM_DUMP_METHOD void MachineConstantPool::dump() const { print(dbgs()); } 1532 #endif 1533