1 //===- AsmPrinter.cpp - Common AsmPrinter code ----------------------------===// 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 // This file implements the AsmPrinter class. 10 // 11 //===----------------------------------------------------------------------===// 12 13 #include "llvm/CodeGen/AsmPrinter.h" 14 #include "CodeViewDebug.h" 15 #include "DwarfDebug.h" 16 #include "DwarfException.h" 17 #include "PseudoProbePrinter.h" 18 #include "WasmException.h" 19 #include "WinCFGuard.h" 20 #include "WinException.h" 21 #include "llvm/ADT/APFloat.h" 22 #include "llvm/ADT/APInt.h" 23 #include "llvm/ADT/DenseMap.h" 24 #include "llvm/ADT/STLExtras.h" 25 #include "llvm/ADT/SmallPtrSet.h" 26 #include "llvm/ADT/SmallString.h" 27 #include "llvm/ADT/SmallVector.h" 28 #include "llvm/ADT/Statistic.h" 29 #include "llvm/ADT/StringRef.h" 30 #include "llvm/ADT/Triple.h" 31 #include "llvm/ADT/Twine.h" 32 #include "llvm/Analysis/ConstantFolding.h" 33 #include "llvm/Analysis/EHPersonalities.h" 34 #include "llvm/Analysis/MemoryLocation.h" 35 #include "llvm/Analysis/OptimizationRemarkEmitter.h" 36 #include "llvm/BinaryFormat/COFF.h" 37 #include "llvm/BinaryFormat/Dwarf.h" 38 #include "llvm/BinaryFormat/ELF.h" 39 #include "llvm/CodeGen/GCMetadata.h" 40 #include "llvm/CodeGen/GCMetadataPrinter.h" 41 #include "llvm/CodeGen/MachineBasicBlock.h" 42 #include "llvm/CodeGen/MachineConstantPool.h" 43 #include "llvm/CodeGen/MachineDominators.h" 44 #include "llvm/CodeGen/MachineFrameInfo.h" 45 #include "llvm/CodeGen/MachineFunction.h" 46 #include "llvm/CodeGen/MachineFunctionPass.h" 47 #include "llvm/CodeGen/MachineInstr.h" 48 #include "llvm/CodeGen/MachineInstrBundle.h" 49 #include "llvm/CodeGen/MachineJumpTableInfo.h" 50 #include "llvm/CodeGen/MachineLoopInfo.h" 51 #include "llvm/CodeGen/MachineMemOperand.h" 52 #include "llvm/CodeGen/MachineModuleInfo.h" 53 #include "llvm/CodeGen/MachineModuleInfoImpls.h" 54 #include "llvm/CodeGen/MachineOperand.h" 55 #include "llvm/CodeGen/MachineOptimizationRemarkEmitter.h" 56 #include "llvm/CodeGen/StackMaps.h" 57 #include "llvm/CodeGen/TargetFrameLowering.h" 58 #include "llvm/CodeGen/TargetInstrInfo.h" 59 #include "llvm/CodeGen/TargetLowering.h" 60 #include "llvm/CodeGen/TargetOpcodes.h" 61 #include "llvm/CodeGen/TargetRegisterInfo.h" 62 #include "llvm/Config/config.h" 63 #include "llvm/IR/BasicBlock.h" 64 #include "llvm/IR/Comdat.h" 65 #include "llvm/IR/Constant.h" 66 #include "llvm/IR/Constants.h" 67 #include "llvm/IR/DataLayout.h" 68 #include "llvm/IR/DebugInfoMetadata.h" 69 #include "llvm/IR/DerivedTypes.h" 70 #include "llvm/IR/Function.h" 71 #include "llvm/IR/GCStrategy.h" 72 #include "llvm/IR/GlobalAlias.h" 73 #include "llvm/IR/GlobalIFunc.h" 74 #include "llvm/IR/GlobalIndirectSymbol.h" 75 #include "llvm/IR/GlobalObject.h" 76 #include "llvm/IR/GlobalValue.h" 77 #include "llvm/IR/GlobalVariable.h" 78 #include "llvm/IR/Instruction.h" 79 #include "llvm/IR/Mangler.h" 80 #include "llvm/IR/Metadata.h" 81 #include "llvm/IR/Module.h" 82 #include "llvm/IR/Operator.h" 83 #include "llvm/IR/PseudoProbe.h" 84 #include "llvm/IR/Type.h" 85 #include "llvm/IR/Value.h" 86 #include "llvm/MC/MCAsmInfo.h" 87 #include "llvm/MC/MCContext.h" 88 #include "llvm/MC/MCDirectives.h" 89 #include "llvm/MC/MCDwarf.h" 90 #include "llvm/MC/MCExpr.h" 91 #include "llvm/MC/MCInst.h" 92 #include "llvm/MC/MCSection.h" 93 #include "llvm/MC/MCSectionCOFF.h" 94 #include "llvm/MC/MCSectionELF.h" 95 #include "llvm/MC/MCSectionMachO.h" 96 #include "llvm/MC/MCSectionXCOFF.h" 97 #include "llvm/MC/MCStreamer.h" 98 #include "llvm/MC/MCSubtargetInfo.h" 99 #include "llvm/MC/MCSymbol.h" 100 #include "llvm/MC/MCSymbolELF.h" 101 #include "llvm/MC/MCSymbolXCOFF.h" 102 #include "llvm/MC/MCTargetOptions.h" 103 #include "llvm/MC/MCValue.h" 104 #include "llvm/MC/SectionKind.h" 105 #include "llvm/Pass.h" 106 #include "llvm/Remarks/Remark.h" 107 #include "llvm/Remarks/RemarkFormat.h" 108 #include "llvm/Remarks/RemarkStreamer.h" 109 #include "llvm/Remarks/RemarkStringTable.h" 110 #include "llvm/Support/Casting.h" 111 #include "llvm/Support/CommandLine.h" 112 #include "llvm/Support/Compiler.h" 113 #include "llvm/Support/ErrorHandling.h" 114 #include "llvm/Support/FileSystem.h" 115 #include "llvm/Support/Format.h" 116 #include "llvm/Support/MathExtras.h" 117 #include "llvm/Support/Path.h" 118 #include "llvm/Support/TargetRegistry.h" 119 #include "llvm/Support/Timer.h" 120 #include "llvm/Support/raw_ostream.h" 121 #include "llvm/Target/TargetLoweringObjectFile.h" 122 #include "llvm/Target/TargetMachine.h" 123 #include "llvm/Target/TargetOptions.h" 124 #include <algorithm> 125 #include <cassert> 126 #include <cinttypes> 127 #include <cstdint> 128 #include <iterator> 129 #include <limits> 130 #include <memory> 131 #include <string> 132 #include <utility> 133 #include <vector> 134 135 using namespace llvm; 136 137 #define DEBUG_TYPE "asm-printer" 138 139 // FIXME: this option currently only applies to DWARF, and not CodeView, tables 140 static cl::opt<bool> 141 DisableDebugInfoPrinting("disable-debug-info-print", cl::Hidden, 142 cl::desc("Disable debug info printing")); 143 144 const char DWARFGroupName[] = "dwarf"; 145 const char DWARFGroupDescription[] = "DWARF Emission"; 146 const char DbgTimerName[] = "emit"; 147 const char DbgTimerDescription[] = "Debug Info Emission"; 148 const char EHTimerName[] = "write_exception"; 149 const char EHTimerDescription[] = "DWARF Exception Writer"; 150 const char CFGuardName[] = "Control Flow Guard"; 151 const char CFGuardDescription[] = "Control Flow Guard"; 152 const char CodeViewLineTablesGroupName[] = "linetables"; 153 const char CodeViewLineTablesGroupDescription[] = "CodeView Line Tables"; 154 const char PPTimerName[] = "emit"; 155 const char PPTimerDescription[] = "Pseudo Probe Emission"; 156 const char PPGroupName[] = "pseudo probe"; 157 const char PPGroupDescription[] = "Pseudo Probe Emission"; 158 159 STATISTIC(EmittedInsts, "Number of machine instrs printed"); 160 161 char AsmPrinter::ID = 0; 162 163 using gcp_map_type = DenseMap<GCStrategy *, std::unique_ptr<GCMetadataPrinter>>; 164 165 static gcp_map_type &getGCMap(void *&P) { 166 if (!P) 167 P = new gcp_map_type(); 168 return *(gcp_map_type*)P; 169 } 170 171 /// getGVAlignment - Return the alignment to use for the specified global 172 /// value. This rounds up to the preferred alignment if possible and legal. 173 Align AsmPrinter::getGVAlignment(const GlobalObject *GV, const DataLayout &DL, 174 Align InAlign) { 175 Align Alignment; 176 if (const GlobalVariable *GVar = dyn_cast<GlobalVariable>(GV)) 177 Alignment = DL.getPreferredAlign(GVar); 178 179 // If InAlign is specified, round it to it. 180 if (InAlign > Alignment) 181 Alignment = InAlign; 182 183 // If the GV has a specified alignment, take it into account. 184 const MaybeAlign GVAlign(GV->getAlignment()); 185 if (!GVAlign) 186 return Alignment; 187 188 assert(GVAlign && "GVAlign must be set"); 189 190 // If the GVAlign is larger than NumBits, or if we are required to obey 191 // NumBits because the GV has an assigned section, obey it. 192 if (*GVAlign > Alignment || GV->hasSection()) 193 Alignment = *GVAlign; 194 return Alignment; 195 } 196 197 AsmPrinter::AsmPrinter(TargetMachine &tm, std::unique_ptr<MCStreamer> Streamer) 198 : MachineFunctionPass(ID), TM(tm), MAI(tm.getMCAsmInfo()), 199 OutContext(Streamer->getContext()), OutStreamer(std::move(Streamer)) { 200 VerboseAsm = OutStreamer->isVerboseAsm(); 201 } 202 203 AsmPrinter::~AsmPrinter() { 204 assert(!DD && Handlers.size() == NumUserHandlers && 205 "Debug/EH info didn't get finalized"); 206 207 if (GCMetadataPrinters) { 208 gcp_map_type &GCMap = getGCMap(GCMetadataPrinters); 209 210 delete &GCMap; 211 GCMetadataPrinters = nullptr; 212 } 213 } 214 215 bool AsmPrinter::isPositionIndependent() const { 216 return TM.isPositionIndependent(); 217 } 218 219 /// getFunctionNumber - Return a unique ID for the current function. 220 unsigned AsmPrinter::getFunctionNumber() const { 221 return MF->getFunctionNumber(); 222 } 223 224 const TargetLoweringObjectFile &AsmPrinter::getObjFileLowering() const { 225 return *TM.getObjFileLowering(); 226 } 227 228 const DataLayout &AsmPrinter::getDataLayout() const { 229 return MMI->getModule()->getDataLayout(); 230 } 231 232 // Do not use the cached DataLayout because some client use it without a Module 233 // (dsymutil, llvm-dwarfdump). 234 unsigned AsmPrinter::getPointerSize() const { 235 return TM.getPointerSize(0); // FIXME: Default address space 236 } 237 238 const MCSubtargetInfo &AsmPrinter::getSubtargetInfo() const { 239 assert(MF && "getSubtargetInfo requires a valid MachineFunction!"); 240 return MF->getSubtarget<MCSubtargetInfo>(); 241 } 242 243 void AsmPrinter::EmitToStreamer(MCStreamer &S, const MCInst &Inst) { 244 S.emitInstruction(Inst, getSubtargetInfo()); 245 } 246 247 void AsmPrinter::emitInitialRawDwarfLocDirective(const MachineFunction &MF) { 248 if (DD) { 249 assert(OutStreamer->hasRawTextSupport() && 250 "Expected assembly output mode."); 251 (void)DD->emitInitialLocDirective(MF, /*CUID=*/0); 252 } 253 } 254 255 /// getCurrentSection() - Return the current section we are emitting to. 256 const MCSection *AsmPrinter::getCurrentSection() const { 257 return OutStreamer->getCurrentSectionOnly(); 258 } 259 260 void AsmPrinter::getAnalysisUsage(AnalysisUsage &AU) const { 261 AU.setPreservesAll(); 262 MachineFunctionPass::getAnalysisUsage(AU); 263 AU.addRequired<MachineOptimizationRemarkEmitterPass>(); 264 AU.addRequired<GCModuleInfo>(); 265 } 266 267 bool AsmPrinter::doInitialization(Module &M) { 268 auto *MMIWP = getAnalysisIfAvailable<MachineModuleInfoWrapperPass>(); 269 MMI = MMIWP ? &MMIWP->getMMI() : nullptr; 270 271 // Initialize TargetLoweringObjectFile. 272 const_cast<TargetLoweringObjectFile&>(getObjFileLowering()) 273 .Initialize(OutContext, TM); 274 275 const_cast<TargetLoweringObjectFile &>(getObjFileLowering()) 276 .getModuleMetadata(M); 277 278 OutStreamer->InitSections(false); 279 280 if (DisableDebugInfoPrinting) 281 MMI->setDebugInfoAvailability(false); 282 283 // Emit the version-min deployment target directive if needed. 284 // 285 // FIXME: If we end up with a collection of these sorts of Darwin-specific 286 // or ELF-specific things, it may make sense to have a platform helper class 287 // that will work with the target helper class. For now keep it here, as the 288 // alternative is duplicated code in each of the target asm printers that 289 // use the directive, where it would need the same conditionalization 290 // anyway. 291 const Triple &Target = TM.getTargetTriple(); 292 OutStreamer->emitVersionForTarget(Target, M.getSDKVersion()); 293 294 // Allow the target to emit any magic that it wants at the start of the file. 295 emitStartOfAsmFile(M); 296 297 // Very minimal debug info. It is ignored if we emit actual debug info. If we 298 // don't, this at least helps the user find where a global came from. 299 if (MAI->hasSingleParameterDotFile()) { 300 // .file "foo.c" 301 302 SmallString<128> FileName; 303 if (MAI->hasBasenameOnlyForFileDirective()) 304 FileName = llvm::sys::path::filename(M.getSourceFileName()); 305 else 306 FileName = M.getSourceFileName(); 307 if (MAI->hasFourStringsDotFile()) { 308 #ifdef PACKAGE_VENDOR 309 const char VerStr[] = 310 PACKAGE_VENDOR " " PACKAGE_NAME " version " PACKAGE_VERSION; 311 #else 312 const char VerStr[] = PACKAGE_NAME " version " PACKAGE_VERSION; 313 #endif 314 // TODO: Add timestamp and description. 315 OutStreamer->emitFileDirective(FileName, VerStr, "", ""); 316 } else { 317 OutStreamer->emitFileDirective(FileName); 318 } 319 } 320 321 GCModuleInfo *MI = getAnalysisIfAvailable<GCModuleInfo>(); 322 assert(MI && "AsmPrinter didn't require GCModuleInfo?"); 323 for (auto &I : *MI) 324 if (GCMetadataPrinter *MP = GetOrCreateGCPrinter(*I)) 325 MP->beginAssembly(M, *MI, *this); 326 327 // Emit module-level inline asm if it exists. 328 if (!M.getModuleInlineAsm().empty()) { 329 // We're at the module level. Construct MCSubtarget from the default CPU 330 // and target triple. 331 std::unique_ptr<MCSubtargetInfo> STI(TM.getTarget().createMCSubtargetInfo( 332 TM.getTargetTriple().str(), TM.getTargetCPU(), 333 TM.getTargetFeatureString())); 334 assert(STI && "Unable to create subtarget info"); 335 OutStreamer->AddComment("Start of file scope inline assembly"); 336 OutStreamer->AddBlankLine(); 337 emitInlineAsm(M.getModuleInlineAsm() + "\n", 338 OutContext.getSubtargetCopy(*STI), TM.Options.MCOptions); 339 OutStreamer->AddComment("End of file scope inline assembly"); 340 OutStreamer->AddBlankLine(); 341 } 342 343 if (MAI->doesSupportDebugInformation()) { 344 bool EmitCodeView = M.getCodeViewFlag(); 345 if (EmitCodeView && TM.getTargetTriple().isOSWindows()) { 346 Handlers.emplace_back(std::make_unique<CodeViewDebug>(this), 347 DbgTimerName, DbgTimerDescription, 348 CodeViewLineTablesGroupName, 349 CodeViewLineTablesGroupDescription); 350 } 351 if (!EmitCodeView || M.getDwarfVersion()) { 352 if (!DisableDebugInfoPrinting) { 353 DD = new DwarfDebug(this); 354 Handlers.emplace_back(std::unique_ptr<DwarfDebug>(DD), DbgTimerName, 355 DbgTimerDescription, DWARFGroupName, 356 DWARFGroupDescription); 357 } 358 } 359 } 360 361 if (M.getNamedMetadata(PseudoProbeDescMetadataName)) { 362 PP = new PseudoProbeHandler(this); 363 Handlers.emplace_back(std::unique_ptr<PseudoProbeHandler>(PP), PPTimerName, 364 PPTimerDescription, PPGroupName, PPGroupDescription); 365 } 366 367 switch (MAI->getExceptionHandlingType()) { 368 case ExceptionHandling::None: 369 // We may want to emit CFI for debug. 370 LLVM_FALLTHROUGH; 371 case ExceptionHandling::SjLj: 372 case ExceptionHandling::DwarfCFI: 373 case ExceptionHandling::ARM: 374 for (auto &F : M.getFunctionList()) { 375 if (getFunctionCFISectionType(F) != CFISection::None) 376 ModuleCFISection = getFunctionCFISectionType(F); 377 // If any function needsUnwindTableEntry(), it needs .eh_frame and hence 378 // the module needs .eh_frame. If we have found that case, we are done. 379 if (ModuleCFISection == CFISection::EH) 380 break; 381 } 382 assert(MAI->getExceptionHandlingType() == ExceptionHandling::DwarfCFI || 383 ModuleCFISection != CFISection::EH); 384 break; 385 default: 386 break; 387 } 388 389 EHStreamer *ES = nullptr; 390 switch (MAI->getExceptionHandlingType()) { 391 case ExceptionHandling::None: 392 if (!needsCFIForDebug()) 393 break; 394 LLVM_FALLTHROUGH; 395 case ExceptionHandling::SjLj: 396 case ExceptionHandling::DwarfCFI: 397 ES = new DwarfCFIException(this); 398 break; 399 case ExceptionHandling::ARM: 400 ES = new ARMException(this); 401 break; 402 case ExceptionHandling::WinEH: 403 switch (MAI->getWinEHEncodingType()) { 404 default: llvm_unreachable("unsupported unwinding information encoding"); 405 case WinEH::EncodingType::Invalid: 406 break; 407 case WinEH::EncodingType::X86: 408 case WinEH::EncodingType::Itanium: 409 ES = new WinException(this); 410 break; 411 } 412 break; 413 case ExceptionHandling::Wasm: 414 ES = new WasmException(this); 415 break; 416 case ExceptionHandling::AIX: 417 ES = new AIXException(this); 418 break; 419 } 420 if (ES) 421 Handlers.emplace_back(std::unique_ptr<EHStreamer>(ES), EHTimerName, 422 EHTimerDescription, DWARFGroupName, 423 DWARFGroupDescription); 424 425 // Emit tables for any value of cfguard flag (i.e. cfguard=1 or cfguard=2). 426 if (mdconst::extract_or_null<ConstantInt>(M.getModuleFlag("cfguard"))) 427 Handlers.emplace_back(std::make_unique<WinCFGuard>(this), CFGuardName, 428 CFGuardDescription, DWARFGroupName, 429 DWARFGroupDescription); 430 431 for (const HandlerInfo &HI : Handlers) { 432 NamedRegionTimer T(HI.TimerName, HI.TimerDescription, HI.TimerGroupName, 433 HI.TimerGroupDescription, TimePassesIsEnabled); 434 HI.Handler->beginModule(&M); 435 } 436 437 return false; 438 } 439 440 static bool canBeHidden(const GlobalValue *GV, const MCAsmInfo &MAI) { 441 if (!MAI.hasWeakDefCanBeHiddenDirective()) 442 return false; 443 444 return GV->canBeOmittedFromSymbolTable(); 445 } 446 447 void AsmPrinter::emitLinkage(const GlobalValue *GV, MCSymbol *GVSym) const { 448 GlobalValue::LinkageTypes Linkage = GV->getLinkage(); 449 switch (Linkage) { 450 case GlobalValue::CommonLinkage: 451 case GlobalValue::LinkOnceAnyLinkage: 452 case GlobalValue::LinkOnceODRLinkage: 453 case GlobalValue::WeakAnyLinkage: 454 case GlobalValue::WeakODRLinkage: 455 if (MAI->hasWeakDefDirective()) { 456 // .globl _foo 457 OutStreamer->emitSymbolAttribute(GVSym, MCSA_Global); 458 459 if (!canBeHidden(GV, *MAI)) 460 // .weak_definition _foo 461 OutStreamer->emitSymbolAttribute(GVSym, MCSA_WeakDefinition); 462 else 463 OutStreamer->emitSymbolAttribute(GVSym, MCSA_WeakDefAutoPrivate); 464 } else if (MAI->avoidWeakIfComdat() && GV->hasComdat()) { 465 // .globl _foo 466 OutStreamer->emitSymbolAttribute(GVSym, MCSA_Global); 467 //NOTE: linkonce is handled by the section the symbol was assigned to. 468 } else { 469 // .weak _foo 470 OutStreamer->emitSymbolAttribute(GVSym, MCSA_Weak); 471 } 472 return; 473 case GlobalValue::ExternalLinkage: 474 OutStreamer->emitSymbolAttribute(GVSym, MCSA_Global); 475 return; 476 case GlobalValue::PrivateLinkage: 477 case GlobalValue::InternalLinkage: 478 return; 479 case GlobalValue::ExternalWeakLinkage: 480 case GlobalValue::AvailableExternallyLinkage: 481 case GlobalValue::AppendingLinkage: 482 llvm_unreachable("Should never emit this"); 483 } 484 llvm_unreachable("Unknown linkage type!"); 485 } 486 487 void AsmPrinter::getNameWithPrefix(SmallVectorImpl<char> &Name, 488 const GlobalValue *GV) const { 489 TM.getNameWithPrefix(Name, GV, getObjFileLowering().getMangler()); 490 } 491 492 MCSymbol *AsmPrinter::getSymbol(const GlobalValue *GV) const { 493 return TM.getSymbol(GV); 494 } 495 496 MCSymbol *AsmPrinter::getSymbolPreferLocal(const GlobalValue &GV) const { 497 // On ELF, use .Lfoo$local if GV is a non-interposable GlobalObject with an 498 // exact definion (intersection of GlobalValue::hasExactDefinition() and 499 // !isInterposable()). These linkages include: external, appending, internal, 500 // private. It may be profitable to use a local alias for external. The 501 // assembler would otherwise be conservative and assume a global default 502 // visibility symbol can be interposable, even if the code generator already 503 // assumed it. 504 if (TM.getTargetTriple().isOSBinFormatELF() && GV.canBenefitFromLocalAlias()) { 505 const Module &M = *GV.getParent(); 506 if (TM.getRelocationModel() != Reloc::Static && 507 M.getPIELevel() == PIELevel::Default && GV.isDSOLocal()) 508 return getSymbolWithGlobalValueBase(&GV, "$local"); 509 } 510 return TM.getSymbol(&GV); 511 } 512 513 /// EmitGlobalVariable - Emit the specified global variable to the .s file. 514 void AsmPrinter::emitGlobalVariable(const GlobalVariable *GV) { 515 bool IsEmuTLSVar = TM.useEmulatedTLS() && GV->isThreadLocal(); 516 assert(!(IsEmuTLSVar && GV->hasCommonLinkage()) && 517 "No emulated TLS variables in the common section"); 518 519 // Never emit TLS variable xyz in emulated TLS model. 520 // The initialization value is in __emutls_t.xyz instead of xyz. 521 if (IsEmuTLSVar) 522 return; 523 524 if (GV->hasInitializer()) { 525 // Check to see if this is a special global used by LLVM, if so, emit it. 526 if (emitSpecialLLVMGlobal(GV)) 527 return; 528 529 // Skip the emission of global equivalents. The symbol can be emitted later 530 // on by emitGlobalGOTEquivs in case it turns out to be needed. 531 if (GlobalGOTEquivs.count(getSymbol(GV))) 532 return; 533 534 if (isVerbose()) { 535 // When printing the control variable __emutls_v.*, 536 // we don't need to print the original TLS variable name. 537 GV->printAsOperand(OutStreamer->GetCommentOS(), 538 /*PrintType=*/false, GV->getParent()); 539 OutStreamer->GetCommentOS() << '\n'; 540 } 541 } 542 543 MCSymbol *GVSym = getSymbol(GV); 544 MCSymbol *EmittedSym = GVSym; 545 546 // getOrCreateEmuTLSControlSym only creates the symbol with name and default 547 // attributes. 548 // GV's or GVSym's attributes will be used for the EmittedSym. 549 emitVisibility(EmittedSym, GV->getVisibility(), !GV->isDeclaration()); 550 551 if (!GV->hasInitializer()) // External globals require no extra code. 552 return; 553 554 GVSym->redefineIfPossible(); 555 if (GVSym->isDefined() || GVSym->isVariable()) 556 OutContext.reportError(SMLoc(), "symbol '" + Twine(GVSym->getName()) + 557 "' is already defined"); 558 559 if (MAI->hasDotTypeDotSizeDirective()) 560 OutStreamer->emitSymbolAttribute(EmittedSym, MCSA_ELF_TypeObject); 561 562 SectionKind GVKind = TargetLoweringObjectFile::getKindForGlobal(GV, TM); 563 564 const DataLayout &DL = GV->getParent()->getDataLayout(); 565 uint64_t Size = DL.getTypeAllocSize(GV->getValueType()); 566 567 // If the alignment is specified, we *must* obey it. Overaligning a global 568 // with a specified alignment is a prompt way to break globals emitted to 569 // sections and expected to be contiguous (e.g. ObjC metadata). 570 const Align Alignment = getGVAlignment(GV, DL); 571 572 for (const HandlerInfo &HI : Handlers) { 573 NamedRegionTimer T(HI.TimerName, HI.TimerDescription, 574 HI.TimerGroupName, HI.TimerGroupDescription, 575 TimePassesIsEnabled); 576 HI.Handler->setSymbolSize(GVSym, Size); 577 } 578 579 // Handle common symbols 580 if (GVKind.isCommon()) { 581 if (Size == 0) Size = 1; // .comm Foo, 0 is undefined, avoid it. 582 // .comm _foo, 42, 4 583 const bool SupportsAlignment = 584 getObjFileLowering().getCommDirectiveSupportsAlignment(); 585 OutStreamer->emitCommonSymbol(GVSym, Size, 586 SupportsAlignment ? Alignment.value() : 0); 587 return; 588 } 589 590 // Determine to which section this global should be emitted. 591 MCSection *TheSection = getObjFileLowering().SectionForGlobal(GV, GVKind, TM); 592 593 // If we have a bss global going to a section that supports the 594 // zerofill directive, do so here. 595 if (GVKind.isBSS() && MAI->hasMachoZeroFillDirective() && 596 TheSection->isVirtualSection()) { 597 if (Size == 0) 598 Size = 1; // zerofill of 0 bytes is undefined. 599 emitLinkage(GV, GVSym); 600 // .zerofill __DATA, __bss, _foo, 400, 5 601 OutStreamer->emitZerofill(TheSection, GVSym, Size, Alignment.value()); 602 return; 603 } 604 605 // If this is a BSS local symbol and we are emitting in the BSS 606 // section use .lcomm/.comm directive. 607 if (GVKind.isBSSLocal() && 608 getObjFileLowering().getBSSSection() == TheSection) { 609 if (Size == 0) 610 Size = 1; // .comm Foo, 0 is undefined, avoid it. 611 612 // Use .lcomm only if it supports user-specified alignment. 613 // Otherwise, while it would still be correct to use .lcomm in some 614 // cases (e.g. when Align == 1), the external assembler might enfore 615 // some -unknown- default alignment behavior, which could cause 616 // spurious differences between external and integrated assembler. 617 // Prefer to simply fall back to .local / .comm in this case. 618 if (MAI->getLCOMMDirectiveAlignmentType() != LCOMM::NoAlignment) { 619 // .lcomm _foo, 42 620 OutStreamer->emitLocalCommonSymbol(GVSym, Size, Alignment.value()); 621 return; 622 } 623 624 // .local _foo 625 OutStreamer->emitSymbolAttribute(GVSym, MCSA_Local); 626 // .comm _foo, 42, 4 627 const bool SupportsAlignment = 628 getObjFileLowering().getCommDirectiveSupportsAlignment(); 629 OutStreamer->emitCommonSymbol(GVSym, Size, 630 SupportsAlignment ? Alignment.value() : 0); 631 return; 632 } 633 634 // Handle thread local data for mach-o which requires us to output an 635 // additional structure of data and mangle the original symbol so that we 636 // can reference it later. 637 // 638 // TODO: This should become an "emit thread local global" method on TLOF. 639 // All of this macho specific stuff should be sunk down into TLOFMachO and 640 // stuff like "TLSExtraDataSection" should no longer be part of the parent 641 // TLOF class. This will also make it more obvious that stuff like 642 // MCStreamer::EmitTBSSSymbol is macho specific and only called from macho 643 // specific code. 644 if (GVKind.isThreadLocal() && MAI->hasMachoTBSSDirective()) { 645 // Emit the .tbss symbol 646 MCSymbol *MangSym = 647 OutContext.getOrCreateSymbol(GVSym->getName() + Twine("$tlv$init")); 648 649 if (GVKind.isThreadBSS()) { 650 TheSection = getObjFileLowering().getTLSBSSSection(); 651 OutStreamer->emitTBSSSymbol(TheSection, MangSym, Size, Alignment.value()); 652 } else if (GVKind.isThreadData()) { 653 OutStreamer->SwitchSection(TheSection); 654 655 emitAlignment(Alignment, GV); 656 OutStreamer->emitLabel(MangSym); 657 658 emitGlobalConstant(GV->getParent()->getDataLayout(), 659 GV->getInitializer()); 660 } 661 662 OutStreamer->AddBlankLine(); 663 664 // Emit the variable struct for the runtime. 665 MCSection *TLVSect = getObjFileLowering().getTLSExtraDataSection(); 666 667 OutStreamer->SwitchSection(TLVSect); 668 // Emit the linkage here. 669 emitLinkage(GV, GVSym); 670 OutStreamer->emitLabel(GVSym); 671 672 // Three pointers in size: 673 // - __tlv_bootstrap - used to make sure support exists 674 // - spare pointer, used when mapped by the runtime 675 // - pointer to mangled symbol above with initializer 676 unsigned PtrSize = DL.getPointerTypeSize(GV->getType()); 677 OutStreamer->emitSymbolValue(GetExternalSymbolSymbol("_tlv_bootstrap"), 678 PtrSize); 679 OutStreamer->emitIntValue(0, PtrSize); 680 OutStreamer->emitSymbolValue(MangSym, PtrSize); 681 682 OutStreamer->AddBlankLine(); 683 return; 684 } 685 686 MCSymbol *EmittedInitSym = GVSym; 687 688 OutStreamer->SwitchSection(TheSection); 689 690 emitLinkage(GV, EmittedInitSym); 691 emitAlignment(Alignment, GV); 692 693 OutStreamer->emitLabel(EmittedInitSym); 694 MCSymbol *LocalAlias = getSymbolPreferLocal(*GV); 695 if (LocalAlias != EmittedInitSym) 696 OutStreamer->emitLabel(LocalAlias); 697 698 emitGlobalConstant(GV->getParent()->getDataLayout(), GV->getInitializer()); 699 700 if (MAI->hasDotTypeDotSizeDirective()) 701 // .size foo, 42 702 OutStreamer->emitELFSize(EmittedInitSym, 703 MCConstantExpr::create(Size, OutContext)); 704 705 OutStreamer->AddBlankLine(); 706 } 707 708 /// Emit the directive and value for debug thread local expression 709 /// 710 /// \p Value - The value to emit. 711 /// \p Size - The size of the integer (in bytes) to emit. 712 void AsmPrinter::emitDebugValue(const MCExpr *Value, unsigned Size) const { 713 OutStreamer->emitValue(Value, Size); 714 } 715 716 void AsmPrinter::emitFunctionHeaderComment() {} 717 718 /// EmitFunctionHeader - This method emits the header for the current 719 /// function. 720 void AsmPrinter::emitFunctionHeader() { 721 const Function &F = MF->getFunction(); 722 723 if (isVerbose()) 724 OutStreamer->GetCommentOS() 725 << "-- Begin function " 726 << GlobalValue::dropLLVMManglingEscape(F.getName()) << '\n'; 727 728 // Print out constants referenced by the function 729 emitConstantPool(); 730 731 // Print the 'header' of function. 732 // If basic block sections are desired, explicitly request a unique section 733 // for this function's entry block. 734 if (MF->front().isBeginSection()) 735 MF->setSection(getObjFileLowering().getUniqueSectionForFunction(F, TM)); 736 else 737 MF->setSection(getObjFileLowering().SectionForGlobal(&F, TM)); 738 OutStreamer->SwitchSection(MF->getSection()); 739 740 if (!MAI->hasVisibilityOnlyWithLinkage()) 741 emitVisibility(CurrentFnSym, F.getVisibility()); 742 743 if (MAI->needsFunctionDescriptors()) 744 emitLinkage(&F, CurrentFnDescSym); 745 746 emitLinkage(&F, CurrentFnSym); 747 if (MAI->hasFunctionAlignment()) 748 emitAlignment(MF->getAlignment(), &F); 749 750 if (MAI->hasDotTypeDotSizeDirective()) 751 OutStreamer->emitSymbolAttribute(CurrentFnSym, MCSA_ELF_TypeFunction); 752 753 if (F.hasFnAttribute(Attribute::Cold)) 754 OutStreamer->emitSymbolAttribute(CurrentFnSym, MCSA_Cold); 755 756 if (isVerbose()) { 757 F.printAsOperand(OutStreamer->GetCommentOS(), 758 /*PrintType=*/false, F.getParent()); 759 emitFunctionHeaderComment(); 760 OutStreamer->GetCommentOS() << '\n'; 761 } 762 763 // Emit the prefix data. 764 if (F.hasPrefixData()) { 765 if (MAI->hasSubsectionsViaSymbols()) { 766 // Preserving prefix data on platforms which use subsections-via-symbols 767 // is a bit tricky. Here we introduce a symbol for the prefix data 768 // and use the .alt_entry attribute to mark the function's real entry point 769 // as an alternative entry point to the prefix-data symbol. 770 MCSymbol *PrefixSym = OutContext.createLinkerPrivateTempSymbol(); 771 OutStreamer->emitLabel(PrefixSym); 772 773 emitGlobalConstant(F.getParent()->getDataLayout(), F.getPrefixData()); 774 775 // Emit an .alt_entry directive for the actual function symbol. 776 OutStreamer->emitSymbolAttribute(CurrentFnSym, MCSA_AltEntry); 777 } else { 778 emitGlobalConstant(F.getParent()->getDataLayout(), F.getPrefixData()); 779 } 780 } 781 782 // Emit M NOPs for -fpatchable-function-entry=N,M where M>0. We arbitrarily 783 // place prefix data before NOPs. 784 unsigned PatchableFunctionPrefix = 0; 785 unsigned PatchableFunctionEntry = 0; 786 (void)F.getFnAttribute("patchable-function-prefix") 787 .getValueAsString() 788 .getAsInteger(10, PatchableFunctionPrefix); 789 (void)F.getFnAttribute("patchable-function-entry") 790 .getValueAsString() 791 .getAsInteger(10, PatchableFunctionEntry); 792 if (PatchableFunctionPrefix) { 793 CurrentPatchableFunctionEntrySym = 794 OutContext.createLinkerPrivateTempSymbol(); 795 OutStreamer->emitLabel(CurrentPatchableFunctionEntrySym); 796 emitNops(PatchableFunctionPrefix); 797 } else if (PatchableFunctionEntry) { 798 // May be reassigned when emitting the body, to reference the label after 799 // the initial BTI (AArch64) or endbr32/endbr64 (x86). 800 CurrentPatchableFunctionEntrySym = CurrentFnBegin; 801 } 802 803 // Emit the function descriptor. This is a virtual function to allow targets 804 // to emit their specific function descriptor. Right now it is only used by 805 // the AIX target. The PowerPC 64-bit V1 ELF target also uses function 806 // descriptors and should be converted to use this hook as well. 807 if (MAI->needsFunctionDescriptors()) 808 emitFunctionDescriptor(); 809 810 // Emit the CurrentFnSym. This is a virtual function to allow targets to do 811 // their wild and crazy things as required. 812 emitFunctionEntryLabel(); 813 814 // If the function had address-taken blocks that got deleted, then we have 815 // references to the dangling symbols. Emit them at the start of the function 816 // so that we don't get references to undefined symbols. 817 std::vector<MCSymbol*> DeadBlockSyms; 818 MMI->takeDeletedSymbolsForFunction(&F, DeadBlockSyms); 819 for (unsigned i = 0, e = DeadBlockSyms.size(); i != e; ++i) { 820 OutStreamer->AddComment("Address taken block that was later removed"); 821 OutStreamer->emitLabel(DeadBlockSyms[i]); 822 } 823 824 if (CurrentFnBegin) { 825 if (MAI->useAssignmentForEHBegin()) { 826 MCSymbol *CurPos = OutContext.createTempSymbol(); 827 OutStreamer->emitLabel(CurPos); 828 OutStreamer->emitAssignment(CurrentFnBegin, 829 MCSymbolRefExpr::create(CurPos, OutContext)); 830 } else { 831 OutStreamer->emitLabel(CurrentFnBegin); 832 } 833 } 834 835 // Emit pre-function debug and/or EH information. 836 for (const HandlerInfo &HI : Handlers) { 837 NamedRegionTimer T(HI.TimerName, HI.TimerDescription, HI.TimerGroupName, 838 HI.TimerGroupDescription, TimePassesIsEnabled); 839 HI.Handler->beginFunction(MF); 840 } 841 842 // Emit the prologue data. 843 if (F.hasPrologueData()) 844 emitGlobalConstant(F.getParent()->getDataLayout(), F.getPrologueData()); 845 } 846 847 /// EmitFunctionEntryLabel - Emit the label that is the entrypoint for the 848 /// function. This can be overridden by targets as required to do custom stuff. 849 void AsmPrinter::emitFunctionEntryLabel() { 850 CurrentFnSym->redefineIfPossible(); 851 852 // The function label could have already been emitted if two symbols end up 853 // conflicting due to asm renaming. Detect this and emit an error. 854 if (CurrentFnSym->isVariable()) 855 report_fatal_error("'" + Twine(CurrentFnSym->getName()) + 856 "' is a protected alias"); 857 858 OutStreamer->emitLabel(CurrentFnSym); 859 860 if (TM.getTargetTriple().isOSBinFormatELF()) { 861 MCSymbol *Sym = getSymbolPreferLocal(MF->getFunction()); 862 if (Sym != CurrentFnSym) 863 OutStreamer->emitLabel(Sym); 864 } 865 } 866 867 /// emitComments - Pretty-print comments for instructions. 868 static void emitComments(const MachineInstr &MI, raw_ostream &CommentOS) { 869 const MachineFunction *MF = MI.getMF(); 870 const TargetInstrInfo *TII = MF->getSubtarget().getInstrInfo(); 871 872 // Check for spills and reloads 873 874 // We assume a single instruction only has a spill or reload, not 875 // both. 876 Optional<unsigned> Size; 877 if ((Size = MI.getRestoreSize(TII))) { 878 CommentOS << *Size << "-byte Reload\n"; 879 } else if ((Size = MI.getFoldedRestoreSize(TII))) { 880 if (*Size) { 881 if (*Size == unsigned(MemoryLocation::UnknownSize)) 882 CommentOS << "Unknown-size Folded Reload\n"; 883 else 884 CommentOS << *Size << "-byte Folded Reload\n"; 885 } 886 } else if ((Size = MI.getSpillSize(TII))) { 887 CommentOS << *Size << "-byte Spill\n"; 888 } else if ((Size = MI.getFoldedSpillSize(TII))) { 889 if (*Size) { 890 if (*Size == unsigned(MemoryLocation::UnknownSize)) 891 CommentOS << "Unknown-size Folded Spill\n"; 892 else 893 CommentOS << *Size << "-byte Folded Spill\n"; 894 } 895 } 896 897 // Check for spill-induced copies 898 if (MI.getAsmPrinterFlag(MachineInstr::ReloadReuse)) 899 CommentOS << " Reload Reuse\n"; 900 } 901 902 /// emitImplicitDef - This method emits the specified machine instruction 903 /// that is an implicit def. 904 void AsmPrinter::emitImplicitDef(const MachineInstr *MI) const { 905 Register RegNo = MI->getOperand(0).getReg(); 906 907 SmallString<128> Str; 908 raw_svector_ostream OS(Str); 909 OS << "implicit-def: " 910 << printReg(RegNo, MF->getSubtarget().getRegisterInfo()); 911 912 OutStreamer->AddComment(OS.str()); 913 OutStreamer->AddBlankLine(); 914 } 915 916 static void emitKill(const MachineInstr *MI, AsmPrinter &AP) { 917 std::string Str; 918 raw_string_ostream OS(Str); 919 OS << "kill:"; 920 for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) { 921 const MachineOperand &Op = MI->getOperand(i); 922 assert(Op.isReg() && "KILL instruction must have only register operands"); 923 OS << ' ' << (Op.isDef() ? "def " : "killed ") 924 << printReg(Op.getReg(), AP.MF->getSubtarget().getRegisterInfo()); 925 } 926 AP.OutStreamer->AddComment(OS.str()); 927 AP.OutStreamer->AddBlankLine(); 928 } 929 930 /// emitDebugValueComment - This method handles the target-independent form 931 /// of DBG_VALUE, returning true if it was able to do so. A false return 932 /// means the target will need to handle MI in EmitInstruction. 933 static bool emitDebugValueComment(const MachineInstr *MI, AsmPrinter &AP) { 934 // This code handles only the 4-operand target-independent form. 935 if (MI->isNonListDebugValue() && MI->getNumOperands() != 4) 936 return false; 937 938 SmallString<128> Str; 939 raw_svector_ostream OS(Str); 940 OS << "DEBUG_VALUE: "; 941 942 const DILocalVariable *V = MI->getDebugVariable(); 943 if (auto *SP = dyn_cast<DISubprogram>(V->getScope())) { 944 StringRef Name = SP->getName(); 945 if (!Name.empty()) 946 OS << Name << ":"; 947 } 948 OS << V->getName(); 949 OS << " <- "; 950 951 const DIExpression *Expr = MI->getDebugExpression(); 952 if (Expr->getNumElements()) { 953 OS << '['; 954 ListSeparator LS; 955 for (auto Op : Expr->expr_ops()) { 956 OS << LS << dwarf::OperationEncodingString(Op.getOp()); 957 for (unsigned I = 0; I < Op.getNumArgs(); ++I) 958 OS << ' ' << Op.getArg(I); 959 } 960 OS << "] "; 961 } 962 963 // Register or immediate value. Register 0 means undef. 964 for (const MachineOperand &Op : MI->debug_operands()) { 965 if (&Op != MI->debug_operands().begin()) 966 OS << ", "; 967 switch (Op.getType()) { 968 case MachineOperand::MO_FPImmediate: { 969 APFloat APF = APFloat(Op.getFPImm()->getValueAPF()); 970 Type *ImmTy = Op.getFPImm()->getType(); 971 if (ImmTy->isBFloatTy() || ImmTy->isHalfTy() || ImmTy->isFloatTy() || 972 ImmTy->isDoubleTy()) { 973 OS << APF.convertToDouble(); 974 } else { 975 // There is no good way to print long double. Convert a copy to 976 // double. Ah well, it's only a comment. 977 bool ignored; 978 APF.convert(APFloat::IEEEdouble(), APFloat::rmNearestTiesToEven, 979 &ignored); 980 OS << "(long double) " << APF.convertToDouble(); 981 } 982 break; 983 } 984 case MachineOperand::MO_Immediate: { 985 OS << Op.getImm(); 986 break; 987 } 988 case MachineOperand::MO_CImmediate: { 989 Op.getCImm()->getValue().print(OS, false /*isSigned*/); 990 break; 991 } 992 case MachineOperand::MO_TargetIndex: { 993 OS << "!target-index(" << Op.getIndex() << "," << Op.getOffset() << ")"; 994 // NOTE: Want this comment at start of line, don't emit with AddComment. 995 AP.OutStreamer->emitRawComment(OS.str()); 996 break; 997 } 998 case MachineOperand::MO_Register: 999 case MachineOperand::MO_FrameIndex: { 1000 Register Reg; 1001 Optional<StackOffset> Offset; 1002 if (Op.isReg()) { 1003 Reg = Op.getReg(); 1004 } else { 1005 const TargetFrameLowering *TFI = 1006 AP.MF->getSubtarget().getFrameLowering(); 1007 Offset = TFI->getFrameIndexReference(*AP.MF, Op.getIndex(), Reg); 1008 } 1009 if (!Reg) { 1010 // Suppress offset, it is not meaningful here. 1011 OS << "undef"; 1012 break; 1013 } 1014 // The second operand is only an offset if it's an immediate. 1015 if (MI->isIndirectDebugValue()) 1016 Offset = StackOffset::getFixed(MI->getDebugOffset().getImm()); 1017 if (Offset) 1018 OS << '['; 1019 OS << printReg(Reg, AP.MF->getSubtarget().getRegisterInfo()); 1020 if (Offset) 1021 OS << '+' << Offset->getFixed() << ']'; 1022 break; 1023 } 1024 default: 1025 llvm_unreachable("Unknown operand type"); 1026 } 1027 } 1028 1029 // NOTE: Want this comment at start of line, don't emit with AddComment. 1030 AP.OutStreamer->emitRawComment(OS.str()); 1031 return true; 1032 } 1033 1034 /// This method handles the target-independent form of DBG_LABEL, returning 1035 /// true if it was able to do so. A false return means the target will need 1036 /// to handle MI in EmitInstruction. 1037 static bool emitDebugLabelComment(const MachineInstr *MI, AsmPrinter &AP) { 1038 if (MI->getNumOperands() != 1) 1039 return false; 1040 1041 SmallString<128> Str; 1042 raw_svector_ostream OS(Str); 1043 OS << "DEBUG_LABEL: "; 1044 1045 const DILabel *V = MI->getDebugLabel(); 1046 if (auto *SP = dyn_cast<DISubprogram>( 1047 V->getScope()->getNonLexicalBlockFileScope())) { 1048 StringRef Name = SP->getName(); 1049 if (!Name.empty()) 1050 OS << Name << ":"; 1051 } 1052 OS << V->getName(); 1053 1054 // NOTE: Want this comment at start of line, don't emit with AddComment. 1055 AP.OutStreamer->emitRawComment(OS.str()); 1056 return true; 1057 } 1058 1059 AsmPrinter::CFISection 1060 AsmPrinter::getFunctionCFISectionType(const Function &F) const { 1061 // Ignore functions that won't get emitted. 1062 if (F.isDeclarationForLinker()) 1063 return CFISection::None; 1064 1065 if (MAI->getExceptionHandlingType() == ExceptionHandling::DwarfCFI && 1066 F.needsUnwindTableEntry()) 1067 return CFISection::EH; 1068 1069 if (MMI->hasDebugInfo() || TM.Options.ForceDwarfFrameSection) 1070 return CFISection::Debug; 1071 1072 return CFISection::None; 1073 } 1074 1075 AsmPrinter::CFISection 1076 AsmPrinter::getFunctionCFISectionType(const MachineFunction &MF) const { 1077 return getFunctionCFISectionType(MF.getFunction()); 1078 } 1079 1080 bool AsmPrinter::needsSEHMoves() { 1081 return MAI->usesWindowsCFI() && MF->getFunction().needsUnwindTableEntry(); 1082 } 1083 1084 bool AsmPrinter::needsCFIForDebug() const { 1085 return MAI->getExceptionHandlingType() == ExceptionHandling::None && 1086 MAI->doesUseCFIForDebug() && ModuleCFISection == CFISection::Debug; 1087 } 1088 1089 void AsmPrinter::emitCFIInstruction(const MachineInstr &MI) { 1090 ExceptionHandling ExceptionHandlingType = MAI->getExceptionHandlingType(); 1091 if (!needsCFIForDebug() && 1092 ExceptionHandlingType != ExceptionHandling::DwarfCFI && 1093 ExceptionHandlingType != ExceptionHandling::ARM) 1094 return; 1095 1096 if (getFunctionCFISectionType(*MF) == CFISection::None) 1097 return; 1098 1099 // If there is no "real" instruction following this CFI instruction, skip 1100 // emitting it; it would be beyond the end of the function's FDE range. 1101 auto *MBB = MI.getParent(); 1102 auto I = std::next(MI.getIterator()); 1103 while (I != MBB->end() && I->isTransient()) 1104 ++I; 1105 if (I == MBB->instr_end() && 1106 MBB->getReverseIterator() == MBB->getParent()->rbegin()) 1107 return; 1108 1109 const std::vector<MCCFIInstruction> &Instrs = MF->getFrameInstructions(); 1110 unsigned CFIIndex = MI.getOperand(0).getCFIIndex(); 1111 const MCCFIInstruction &CFI = Instrs[CFIIndex]; 1112 emitCFIInstruction(CFI); 1113 } 1114 1115 void AsmPrinter::emitFrameAlloc(const MachineInstr &MI) { 1116 // The operands are the MCSymbol and the frame offset of the allocation. 1117 MCSymbol *FrameAllocSym = MI.getOperand(0).getMCSymbol(); 1118 int FrameOffset = MI.getOperand(1).getImm(); 1119 1120 // Emit a symbol assignment. 1121 OutStreamer->emitAssignment(FrameAllocSym, 1122 MCConstantExpr::create(FrameOffset, OutContext)); 1123 } 1124 1125 /// Returns the BB metadata to be emitted in the .llvm_bb_addr_map section for a 1126 /// given basic block. This can be used to capture more precise profile 1127 /// information. We use the last 4 bits (LSBs) to encode the following 1128 /// information: 1129 /// * (1): set if return block (ret or tail call). 1130 /// * (2): set if ends with a tail call. 1131 /// * (3): set if exception handling (EH) landing pad. 1132 /// * (4): set if the block can fall through to its next. 1133 /// The remaining bits are zero. 1134 static unsigned getBBAddrMapMetadata(const MachineBasicBlock &MBB) { 1135 const TargetInstrInfo *TII = MBB.getParent()->getSubtarget().getInstrInfo(); 1136 return ((unsigned)MBB.isReturnBlock()) | 1137 ((!MBB.empty() && TII->isTailCall(MBB.back())) << 1) | 1138 (MBB.isEHPad() << 2) | 1139 (const_cast<MachineBasicBlock &>(MBB).canFallThrough() << 3); 1140 } 1141 1142 void AsmPrinter::emitBBAddrMapSection(const MachineFunction &MF) { 1143 MCSection *BBAddrMapSection = 1144 getObjFileLowering().getBBAddrMapSection(*MF.getSection()); 1145 assert(BBAddrMapSection && ".llvm_bb_addr_map section is not initialized."); 1146 1147 const MCSymbol *FunctionSymbol = getFunctionBegin(); 1148 1149 OutStreamer->PushSection(); 1150 OutStreamer->SwitchSection(BBAddrMapSection); 1151 OutStreamer->emitSymbolValue(FunctionSymbol, getPointerSize()); 1152 // Emit the total number of basic blocks in this function. 1153 OutStreamer->emitULEB128IntValue(MF.size()); 1154 // Emit BB Information for each basic block in the funciton. 1155 for (const MachineBasicBlock &MBB : MF) { 1156 const MCSymbol *MBBSymbol = 1157 MBB.isEntryBlock() ? FunctionSymbol : MBB.getSymbol(); 1158 // Emit the basic block offset. 1159 emitLabelDifferenceAsULEB128(MBBSymbol, FunctionSymbol); 1160 // Emit the basic block size. When BBs have alignments, their size cannot 1161 // always be computed from their offsets. 1162 emitLabelDifferenceAsULEB128(MBB.getEndSymbol(), MBBSymbol); 1163 OutStreamer->emitULEB128IntValue(getBBAddrMapMetadata(MBB)); 1164 } 1165 OutStreamer->PopSection(); 1166 } 1167 1168 void AsmPrinter::emitPseudoProbe(const MachineInstr &MI) { 1169 auto GUID = MI.getOperand(0).getImm(); 1170 auto Index = MI.getOperand(1).getImm(); 1171 auto Type = MI.getOperand(2).getImm(); 1172 auto Attr = MI.getOperand(3).getImm(); 1173 DILocation *DebugLoc = MI.getDebugLoc(); 1174 PP->emitPseudoProbe(GUID, Index, Type, Attr, DebugLoc); 1175 } 1176 1177 void AsmPrinter::emitStackSizeSection(const MachineFunction &MF) { 1178 if (!MF.getTarget().Options.EmitStackSizeSection) 1179 return; 1180 1181 MCSection *StackSizeSection = 1182 getObjFileLowering().getStackSizesSection(*getCurrentSection()); 1183 if (!StackSizeSection) 1184 return; 1185 1186 const MachineFrameInfo &FrameInfo = MF.getFrameInfo(); 1187 // Don't emit functions with dynamic stack allocations. 1188 if (FrameInfo.hasVarSizedObjects()) 1189 return; 1190 1191 OutStreamer->PushSection(); 1192 OutStreamer->SwitchSection(StackSizeSection); 1193 1194 const MCSymbol *FunctionSymbol = getFunctionBegin(); 1195 uint64_t StackSize = FrameInfo.getStackSize(); 1196 OutStreamer->emitSymbolValue(FunctionSymbol, TM.getProgramPointerSize()); 1197 OutStreamer->emitULEB128IntValue(StackSize); 1198 1199 OutStreamer->PopSection(); 1200 } 1201 1202 void AsmPrinter::emitStackUsage(const MachineFunction &MF) { 1203 const std::string &OutputFilename = MF.getTarget().Options.StackUsageOutput; 1204 1205 // OutputFilename empty implies -fstack-usage is not passed. 1206 if (OutputFilename.empty()) 1207 return; 1208 1209 const MachineFrameInfo &FrameInfo = MF.getFrameInfo(); 1210 uint64_t StackSize = FrameInfo.getStackSize(); 1211 1212 if (StackUsageStream == nullptr) { 1213 std::error_code EC; 1214 StackUsageStream = 1215 std::make_unique<raw_fd_ostream>(OutputFilename, EC, sys::fs::OF_Text); 1216 if (EC) { 1217 errs() << "Could not open file: " << EC.message(); 1218 return; 1219 } 1220 } 1221 1222 *StackUsageStream << MF.getFunction().getParent()->getName(); 1223 if (const DISubprogram *DSP = MF.getFunction().getSubprogram()) 1224 *StackUsageStream << ':' << DSP->getLine(); 1225 1226 *StackUsageStream << ':' << MF.getName() << '\t' << StackSize << '\t'; 1227 if (FrameInfo.hasVarSizedObjects()) 1228 *StackUsageStream << "dynamic\n"; 1229 else 1230 *StackUsageStream << "static\n"; 1231 } 1232 1233 static bool needFuncLabelsForEHOrDebugInfo(const MachineFunction &MF) { 1234 MachineModuleInfo &MMI = MF.getMMI(); 1235 if (!MF.getLandingPads().empty() || MF.hasEHFunclets() || MMI.hasDebugInfo()) 1236 return true; 1237 1238 // We might emit an EH table that uses function begin and end labels even if 1239 // we don't have any landingpads. 1240 if (!MF.getFunction().hasPersonalityFn()) 1241 return false; 1242 return !isNoOpWithoutInvoke( 1243 classifyEHPersonality(MF.getFunction().getPersonalityFn())); 1244 } 1245 1246 /// EmitFunctionBody - This method emits the body and trailer for a 1247 /// function. 1248 void AsmPrinter::emitFunctionBody() { 1249 emitFunctionHeader(); 1250 1251 // Emit target-specific gunk before the function body. 1252 emitFunctionBodyStart(); 1253 1254 if (isVerbose()) { 1255 // Get MachineDominatorTree or compute it on the fly if it's unavailable 1256 MDT = getAnalysisIfAvailable<MachineDominatorTree>(); 1257 if (!MDT) { 1258 OwnedMDT = std::make_unique<MachineDominatorTree>(); 1259 OwnedMDT->getBase().recalculate(*MF); 1260 MDT = OwnedMDT.get(); 1261 } 1262 1263 // Get MachineLoopInfo or compute it on the fly if it's unavailable 1264 MLI = getAnalysisIfAvailable<MachineLoopInfo>(); 1265 if (!MLI) { 1266 OwnedMLI = std::make_unique<MachineLoopInfo>(); 1267 OwnedMLI->getBase().analyze(MDT->getBase()); 1268 MLI = OwnedMLI.get(); 1269 } 1270 } 1271 1272 // Print out code for the function. 1273 bool HasAnyRealCode = false; 1274 int NumInstsInFunction = 0; 1275 1276 bool CanDoExtraAnalysis = ORE->allowExtraAnalysis(DEBUG_TYPE); 1277 for (auto &MBB : *MF) { 1278 // Print a label for the basic block. 1279 emitBasicBlockStart(MBB); 1280 DenseMap<StringRef, unsigned> MnemonicCounts; 1281 for (auto &MI : MBB) { 1282 // Print the assembly for the instruction. 1283 if (!MI.isPosition() && !MI.isImplicitDef() && !MI.isKill() && 1284 !MI.isDebugInstr()) { 1285 HasAnyRealCode = true; 1286 ++NumInstsInFunction; 1287 } 1288 1289 // If there is a pre-instruction symbol, emit a label for it here. 1290 if (MCSymbol *S = MI.getPreInstrSymbol()) 1291 OutStreamer->emitLabel(S); 1292 1293 for (const HandlerInfo &HI : Handlers) { 1294 NamedRegionTimer T(HI.TimerName, HI.TimerDescription, HI.TimerGroupName, 1295 HI.TimerGroupDescription, TimePassesIsEnabled); 1296 HI.Handler->beginInstruction(&MI); 1297 } 1298 1299 if (isVerbose()) 1300 emitComments(MI, OutStreamer->GetCommentOS()); 1301 1302 switch (MI.getOpcode()) { 1303 case TargetOpcode::CFI_INSTRUCTION: 1304 emitCFIInstruction(MI); 1305 break; 1306 case TargetOpcode::LOCAL_ESCAPE: 1307 emitFrameAlloc(MI); 1308 break; 1309 case TargetOpcode::ANNOTATION_LABEL: 1310 case TargetOpcode::EH_LABEL: 1311 case TargetOpcode::GC_LABEL: 1312 OutStreamer->emitLabel(MI.getOperand(0).getMCSymbol()); 1313 break; 1314 case TargetOpcode::INLINEASM: 1315 case TargetOpcode::INLINEASM_BR: 1316 emitInlineAsm(&MI); 1317 break; 1318 case TargetOpcode::DBG_VALUE: 1319 case TargetOpcode::DBG_VALUE_LIST: 1320 if (isVerbose()) { 1321 if (!emitDebugValueComment(&MI, *this)) 1322 emitInstruction(&MI); 1323 } 1324 break; 1325 case TargetOpcode::DBG_INSTR_REF: 1326 // This instruction reference will have been resolved to a machine 1327 // location, and a nearby DBG_VALUE created. We can safely ignore 1328 // the instruction reference. 1329 break; 1330 case TargetOpcode::DBG_PHI: 1331 // This instruction is only used to label a program point, it's purely 1332 // meta information. 1333 break; 1334 case TargetOpcode::DBG_LABEL: 1335 if (isVerbose()) { 1336 if (!emitDebugLabelComment(&MI, *this)) 1337 emitInstruction(&MI); 1338 } 1339 break; 1340 case TargetOpcode::IMPLICIT_DEF: 1341 if (isVerbose()) emitImplicitDef(&MI); 1342 break; 1343 case TargetOpcode::KILL: 1344 if (isVerbose()) emitKill(&MI, *this); 1345 break; 1346 case TargetOpcode::PSEUDO_PROBE: 1347 emitPseudoProbe(MI); 1348 break; 1349 case TargetOpcode::ARITH_FENCE: 1350 if (isVerbose()) 1351 OutStreamer->emitRawComment("ARITH_FENCE"); 1352 break; 1353 default: 1354 emitInstruction(&MI); 1355 if (CanDoExtraAnalysis) { 1356 MCInst MCI; 1357 MCI.setOpcode(MI.getOpcode()); 1358 auto Name = OutStreamer->getMnemonic(MCI); 1359 auto I = MnemonicCounts.insert({Name, 0u}); 1360 I.first->second++; 1361 } 1362 break; 1363 } 1364 1365 // If there is a post-instruction symbol, emit a label for it here. 1366 if (MCSymbol *S = MI.getPostInstrSymbol()) 1367 OutStreamer->emitLabel(S); 1368 1369 for (const HandlerInfo &HI : Handlers) { 1370 NamedRegionTimer T(HI.TimerName, HI.TimerDescription, HI.TimerGroupName, 1371 HI.TimerGroupDescription, TimePassesIsEnabled); 1372 HI.Handler->endInstruction(); 1373 } 1374 } 1375 1376 // We must emit temporary symbol for the end of this basic block, if either 1377 // we have BBLabels enabled or if this basic blocks marks the end of a 1378 // section. 1379 if (MF->hasBBLabels() || 1380 (MAI->hasDotTypeDotSizeDirective() && MBB.isEndSection())) 1381 OutStreamer->emitLabel(MBB.getEndSymbol()); 1382 1383 if (MBB.isEndSection()) { 1384 // The size directive for the section containing the entry block is 1385 // handled separately by the function section. 1386 if (!MBB.sameSection(&MF->front())) { 1387 if (MAI->hasDotTypeDotSizeDirective()) { 1388 // Emit the size directive for the basic block section. 1389 const MCExpr *SizeExp = MCBinaryExpr::createSub( 1390 MCSymbolRefExpr::create(MBB.getEndSymbol(), OutContext), 1391 MCSymbolRefExpr::create(CurrentSectionBeginSym, OutContext), 1392 OutContext); 1393 OutStreamer->emitELFSize(CurrentSectionBeginSym, SizeExp); 1394 } 1395 MBBSectionRanges[MBB.getSectionIDNum()] = 1396 MBBSectionRange{CurrentSectionBeginSym, MBB.getEndSymbol()}; 1397 } 1398 } 1399 emitBasicBlockEnd(MBB); 1400 1401 if (CanDoExtraAnalysis) { 1402 // Skip empty blocks. 1403 if (MBB.empty()) 1404 continue; 1405 1406 MachineOptimizationRemarkAnalysis R(DEBUG_TYPE, "InstructionMix", 1407 MBB.begin()->getDebugLoc(), &MBB); 1408 1409 // Generate instruction mix remark. First, sort counts in descending order 1410 // by count and name. 1411 SmallVector<std::pair<StringRef, unsigned>, 128> MnemonicVec; 1412 for (auto &KV : MnemonicCounts) 1413 MnemonicVec.emplace_back(KV.first, KV.second); 1414 1415 sort(MnemonicVec, [](const std::pair<StringRef, unsigned> &A, 1416 const std::pair<StringRef, unsigned> &B) { 1417 if (A.second > B.second) 1418 return true; 1419 if (A.second == B.second) 1420 return StringRef(A.first) < StringRef(B.first); 1421 return false; 1422 }); 1423 R << "BasicBlock: " << ore::NV("BasicBlock", MBB.getName()) << "\n"; 1424 for (auto &KV : MnemonicVec) { 1425 auto Name = (Twine("INST_") + KV.first.trim()).str(); 1426 R << KV.first << ": " << ore::NV(Name, KV.second) << "\n"; 1427 } 1428 ORE->emit(R); 1429 } 1430 } 1431 1432 EmittedInsts += NumInstsInFunction; 1433 MachineOptimizationRemarkAnalysis R(DEBUG_TYPE, "InstructionCount", 1434 MF->getFunction().getSubprogram(), 1435 &MF->front()); 1436 R << ore::NV("NumInstructions", NumInstsInFunction) 1437 << " instructions in function"; 1438 ORE->emit(R); 1439 1440 // If the function is empty and the object file uses .subsections_via_symbols, 1441 // then we need to emit *something* to the function body to prevent the 1442 // labels from collapsing together. Just emit a noop. 1443 // Similarly, don't emit empty functions on Windows either. It can lead to 1444 // duplicate entries (two functions with the same RVA) in the Guard CF Table 1445 // after linking, causing the kernel not to load the binary: 1446 // https://developercommunity.visualstudio.com/content/problem/45366/vc-linker-creates-invalid-dll-with-clang-cl.html 1447 // FIXME: Hide this behind some API in e.g. MCAsmInfo or MCTargetStreamer. 1448 const Triple &TT = TM.getTargetTriple(); 1449 if (!HasAnyRealCode && (MAI->hasSubsectionsViaSymbols() || 1450 (TT.isOSWindows() && TT.isOSBinFormatCOFF()))) { 1451 MCInst Noop = MF->getSubtarget().getInstrInfo()->getNop(); 1452 1453 // Targets can opt-out of emitting the noop here by leaving the opcode 1454 // unspecified. 1455 if (Noop.getOpcode()) { 1456 OutStreamer->AddComment("avoids zero-length function"); 1457 emitNops(1); 1458 } 1459 } 1460 1461 // Switch to the original section in case basic block sections was used. 1462 OutStreamer->SwitchSection(MF->getSection()); 1463 1464 const Function &F = MF->getFunction(); 1465 for (const auto &BB : F) { 1466 if (!BB.hasAddressTaken()) 1467 continue; 1468 MCSymbol *Sym = GetBlockAddressSymbol(&BB); 1469 if (Sym->isDefined()) 1470 continue; 1471 OutStreamer->AddComment("Address of block that was removed by CodeGen"); 1472 OutStreamer->emitLabel(Sym); 1473 } 1474 1475 // Emit target-specific gunk after the function body. 1476 emitFunctionBodyEnd(); 1477 1478 if (needFuncLabelsForEHOrDebugInfo(*MF) || 1479 MAI->hasDotTypeDotSizeDirective()) { 1480 // Create a symbol for the end of function. 1481 CurrentFnEnd = createTempSymbol("func_end"); 1482 OutStreamer->emitLabel(CurrentFnEnd); 1483 } 1484 1485 // If the target wants a .size directive for the size of the function, emit 1486 // it. 1487 if (MAI->hasDotTypeDotSizeDirective()) { 1488 // We can get the size as difference between the function label and the 1489 // temp label. 1490 const MCExpr *SizeExp = MCBinaryExpr::createSub( 1491 MCSymbolRefExpr::create(CurrentFnEnd, OutContext), 1492 MCSymbolRefExpr::create(CurrentFnSymForSize, OutContext), OutContext); 1493 OutStreamer->emitELFSize(CurrentFnSym, SizeExp); 1494 } 1495 1496 for (const HandlerInfo &HI : Handlers) { 1497 NamedRegionTimer T(HI.TimerName, HI.TimerDescription, HI.TimerGroupName, 1498 HI.TimerGroupDescription, TimePassesIsEnabled); 1499 HI.Handler->markFunctionEnd(); 1500 } 1501 1502 MBBSectionRanges[MF->front().getSectionIDNum()] = 1503 MBBSectionRange{CurrentFnBegin, CurrentFnEnd}; 1504 1505 // Print out jump tables referenced by the function. 1506 emitJumpTableInfo(); 1507 1508 // Emit post-function debug and/or EH information. 1509 for (const HandlerInfo &HI : Handlers) { 1510 NamedRegionTimer T(HI.TimerName, HI.TimerDescription, HI.TimerGroupName, 1511 HI.TimerGroupDescription, TimePassesIsEnabled); 1512 HI.Handler->endFunction(MF); 1513 } 1514 1515 // Emit section containing BB address offsets and their metadata, when 1516 // BB labels are requested for this function. Skip empty functions. 1517 if (MF->hasBBLabels() && HasAnyRealCode) 1518 emitBBAddrMapSection(*MF); 1519 1520 // Emit section containing stack size metadata. 1521 emitStackSizeSection(*MF); 1522 1523 // Emit .su file containing function stack size information. 1524 emitStackUsage(*MF); 1525 1526 emitPatchableFunctionEntries(); 1527 1528 if (isVerbose()) 1529 OutStreamer->GetCommentOS() << "-- End function\n"; 1530 1531 OutStreamer->AddBlankLine(); 1532 } 1533 1534 /// Compute the number of Global Variables that uses a Constant. 1535 static unsigned getNumGlobalVariableUses(const Constant *C) { 1536 if (!C) 1537 return 0; 1538 1539 if (isa<GlobalVariable>(C)) 1540 return 1; 1541 1542 unsigned NumUses = 0; 1543 for (auto *CU : C->users()) 1544 NumUses += getNumGlobalVariableUses(dyn_cast<Constant>(CU)); 1545 1546 return NumUses; 1547 } 1548 1549 /// Only consider global GOT equivalents if at least one user is a 1550 /// cstexpr inside an initializer of another global variables. Also, don't 1551 /// handle cstexpr inside instructions. During global variable emission, 1552 /// candidates are skipped and are emitted later in case at least one cstexpr 1553 /// isn't replaced by a PC relative GOT entry access. 1554 static bool isGOTEquivalentCandidate(const GlobalVariable *GV, 1555 unsigned &NumGOTEquivUsers) { 1556 // Global GOT equivalents are unnamed private globals with a constant 1557 // pointer initializer to another global symbol. They must point to a 1558 // GlobalVariable or Function, i.e., as GlobalValue. 1559 if (!GV->hasGlobalUnnamedAddr() || !GV->hasInitializer() || 1560 !GV->isConstant() || !GV->isDiscardableIfUnused() || 1561 !isa<GlobalValue>(GV->getOperand(0))) 1562 return false; 1563 1564 // To be a got equivalent, at least one of its users need to be a constant 1565 // expression used by another global variable. 1566 for (auto *U : GV->users()) 1567 NumGOTEquivUsers += getNumGlobalVariableUses(dyn_cast<Constant>(U)); 1568 1569 return NumGOTEquivUsers > 0; 1570 } 1571 1572 /// Unnamed constant global variables solely contaning a pointer to 1573 /// another globals variable is equivalent to a GOT table entry; it contains the 1574 /// the address of another symbol. Optimize it and replace accesses to these 1575 /// "GOT equivalents" by using the GOT entry for the final global instead. 1576 /// Compute GOT equivalent candidates among all global variables to avoid 1577 /// emitting them if possible later on, after it use is replaced by a GOT entry 1578 /// access. 1579 void AsmPrinter::computeGlobalGOTEquivs(Module &M) { 1580 if (!getObjFileLowering().supportIndirectSymViaGOTPCRel()) 1581 return; 1582 1583 for (const auto &G : M.globals()) { 1584 unsigned NumGOTEquivUsers = 0; 1585 if (!isGOTEquivalentCandidate(&G, NumGOTEquivUsers)) 1586 continue; 1587 1588 const MCSymbol *GOTEquivSym = getSymbol(&G); 1589 GlobalGOTEquivs[GOTEquivSym] = std::make_pair(&G, NumGOTEquivUsers); 1590 } 1591 } 1592 1593 /// Constant expressions using GOT equivalent globals may not be eligible 1594 /// for PC relative GOT entry conversion, in such cases we need to emit such 1595 /// globals we previously omitted in EmitGlobalVariable. 1596 void AsmPrinter::emitGlobalGOTEquivs() { 1597 if (!getObjFileLowering().supportIndirectSymViaGOTPCRel()) 1598 return; 1599 1600 SmallVector<const GlobalVariable *, 8> FailedCandidates; 1601 for (auto &I : GlobalGOTEquivs) { 1602 const GlobalVariable *GV = I.second.first; 1603 unsigned Cnt = I.second.second; 1604 if (Cnt) 1605 FailedCandidates.push_back(GV); 1606 } 1607 GlobalGOTEquivs.clear(); 1608 1609 for (auto *GV : FailedCandidates) 1610 emitGlobalVariable(GV); 1611 } 1612 1613 void AsmPrinter::emitGlobalIndirectSymbol(Module &M, 1614 const GlobalIndirectSymbol& GIS) { 1615 MCSymbol *Name = getSymbol(&GIS); 1616 bool IsFunction = GIS.getValueType()->isFunctionTy(); 1617 // Treat bitcasts of functions as functions also. This is important at least 1618 // on WebAssembly where object and function addresses can't alias each other. 1619 if (!IsFunction) 1620 if (auto *CE = dyn_cast<ConstantExpr>(GIS.getIndirectSymbol())) 1621 if (CE->getOpcode() == Instruction::BitCast) 1622 IsFunction = 1623 CE->getOperand(0)->getType()->getPointerElementType()->isFunctionTy(); 1624 1625 // AIX's assembly directive `.set` is not usable for aliasing purpose, 1626 // so AIX has to use the extra-label-at-definition strategy. At this 1627 // point, all the extra label is emitted, we just have to emit linkage for 1628 // those labels. 1629 if (TM.getTargetTriple().isOSBinFormatXCOFF()) { 1630 assert(!isa<GlobalIFunc>(GIS) && "IFunc is not supported on AIX."); 1631 assert(MAI->hasVisibilityOnlyWithLinkage() && 1632 "Visibility should be handled with emitLinkage() on AIX."); 1633 emitLinkage(&GIS, Name); 1634 // If it's a function, also emit linkage for aliases of function entry 1635 // point. 1636 if (IsFunction) 1637 emitLinkage(&GIS, 1638 getObjFileLowering().getFunctionEntryPointSymbol(&GIS, TM)); 1639 return; 1640 } 1641 1642 if (GIS.hasExternalLinkage() || !MAI->getWeakRefDirective()) 1643 OutStreamer->emitSymbolAttribute(Name, MCSA_Global); 1644 else if (GIS.hasWeakLinkage() || GIS.hasLinkOnceLinkage()) 1645 OutStreamer->emitSymbolAttribute(Name, MCSA_WeakReference); 1646 else 1647 assert(GIS.hasLocalLinkage() && "Invalid alias or ifunc linkage"); 1648 1649 // Set the symbol type to function if the alias has a function type. 1650 // This affects codegen when the aliasee is not a function. 1651 if (IsFunction) 1652 OutStreamer->emitSymbolAttribute(Name, isa<GlobalIFunc>(GIS) 1653 ? MCSA_ELF_TypeIndFunction 1654 : MCSA_ELF_TypeFunction); 1655 1656 emitVisibility(Name, GIS.getVisibility()); 1657 1658 const MCExpr *Expr = lowerConstant(GIS.getIndirectSymbol()); 1659 1660 if (isa<GlobalAlias>(&GIS) && MAI->hasAltEntry() && isa<MCBinaryExpr>(Expr)) 1661 OutStreamer->emitSymbolAttribute(Name, MCSA_AltEntry); 1662 1663 // Emit the directives as assignments aka .set: 1664 OutStreamer->emitAssignment(Name, Expr); 1665 MCSymbol *LocalAlias = getSymbolPreferLocal(GIS); 1666 if (LocalAlias != Name) 1667 OutStreamer->emitAssignment(LocalAlias, Expr); 1668 1669 if (auto *GA = dyn_cast<GlobalAlias>(&GIS)) { 1670 // If the aliasee does not correspond to a symbol in the output, i.e. the 1671 // alias is not of an object or the aliased object is private, then set the 1672 // size of the alias symbol from the type of the alias. We don't do this in 1673 // other situations as the alias and aliasee having differing types but same 1674 // size may be intentional. 1675 const GlobalObject *BaseObject = GA->getBaseObject(); 1676 if (MAI->hasDotTypeDotSizeDirective() && GA->getValueType()->isSized() && 1677 (!BaseObject || BaseObject->hasPrivateLinkage())) { 1678 const DataLayout &DL = M.getDataLayout(); 1679 uint64_t Size = DL.getTypeAllocSize(GA->getValueType()); 1680 OutStreamer->emitELFSize(Name, MCConstantExpr::create(Size, OutContext)); 1681 } 1682 } 1683 } 1684 1685 void AsmPrinter::emitRemarksSection(remarks::RemarkStreamer &RS) { 1686 if (!RS.needsSection()) 1687 return; 1688 1689 remarks::RemarkSerializer &RemarkSerializer = RS.getSerializer(); 1690 1691 Optional<SmallString<128>> Filename; 1692 if (Optional<StringRef> FilenameRef = RS.getFilename()) { 1693 Filename = *FilenameRef; 1694 sys::fs::make_absolute(*Filename); 1695 assert(!Filename->empty() && "The filename can't be empty."); 1696 } 1697 1698 std::string Buf; 1699 raw_string_ostream OS(Buf); 1700 std::unique_ptr<remarks::MetaSerializer> MetaSerializer = 1701 Filename ? RemarkSerializer.metaSerializer(OS, Filename->str()) 1702 : RemarkSerializer.metaSerializer(OS); 1703 MetaSerializer->emit(); 1704 1705 // Switch to the remarks section. 1706 MCSection *RemarksSection = 1707 OutContext.getObjectFileInfo()->getRemarksSection(); 1708 OutStreamer->SwitchSection(RemarksSection); 1709 1710 OutStreamer->emitBinaryData(OS.str()); 1711 } 1712 1713 bool AsmPrinter::doFinalization(Module &M) { 1714 // Set the MachineFunction to nullptr so that we can catch attempted 1715 // accesses to MF specific features at the module level and so that 1716 // we can conditionalize accesses based on whether or not it is nullptr. 1717 MF = nullptr; 1718 1719 // Gather all GOT equivalent globals in the module. We really need two 1720 // passes over the globals: one to compute and another to avoid its emission 1721 // in EmitGlobalVariable, otherwise we would not be able to handle cases 1722 // where the got equivalent shows up before its use. 1723 computeGlobalGOTEquivs(M); 1724 1725 // Emit global variables. 1726 for (const auto &G : M.globals()) 1727 emitGlobalVariable(&G); 1728 1729 // Emit remaining GOT equivalent globals. 1730 emitGlobalGOTEquivs(); 1731 1732 const TargetLoweringObjectFile &TLOF = getObjFileLowering(); 1733 1734 // Emit linkage(XCOFF) and visibility info for declarations 1735 for (const Function &F : M) { 1736 if (!F.isDeclarationForLinker()) 1737 continue; 1738 1739 MCSymbol *Name = getSymbol(&F); 1740 // Function getSymbol gives us the function descriptor symbol for XCOFF. 1741 1742 if (!TM.getTargetTriple().isOSBinFormatXCOFF()) { 1743 GlobalValue::VisibilityTypes V = F.getVisibility(); 1744 if (V == GlobalValue::DefaultVisibility) 1745 continue; 1746 1747 emitVisibility(Name, V, false); 1748 continue; 1749 } 1750 1751 if (F.isIntrinsic()) 1752 continue; 1753 1754 // Handle the XCOFF case. 1755 // Variable `Name` is the function descriptor symbol (see above). Get the 1756 // function entry point symbol. 1757 MCSymbol *FnEntryPointSym = TLOF.getFunctionEntryPointSymbol(&F, TM); 1758 // Emit linkage for the function entry point. 1759 emitLinkage(&F, FnEntryPointSym); 1760 1761 // Emit linkage for the function descriptor. 1762 emitLinkage(&F, Name); 1763 } 1764 1765 // Emit the remarks section contents. 1766 // FIXME: Figure out when is the safest time to emit this section. It should 1767 // not come after debug info. 1768 if (remarks::RemarkStreamer *RS = M.getContext().getMainRemarkStreamer()) 1769 emitRemarksSection(*RS); 1770 1771 TLOF.emitModuleMetadata(*OutStreamer, M); 1772 1773 if (TM.getTargetTriple().isOSBinFormatELF()) { 1774 MachineModuleInfoELF &MMIELF = MMI->getObjFileInfo<MachineModuleInfoELF>(); 1775 1776 // Output stubs for external and common global variables. 1777 MachineModuleInfoELF::SymbolListTy Stubs = MMIELF.GetGVStubList(); 1778 if (!Stubs.empty()) { 1779 OutStreamer->SwitchSection(TLOF.getDataSection()); 1780 const DataLayout &DL = M.getDataLayout(); 1781 1782 emitAlignment(Align(DL.getPointerSize())); 1783 for (const auto &Stub : Stubs) { 1784 OutStreamer->emitLabel(Stub.first); 1785 OutStreamer->emitSymbolValue(Stub.second.getPointer(), 1786 DL.getPointerSize()); 1787 } 1788 } 1789 } 1790 1791 if (TM.getTargetTriple().isOSBinFormatCOFF()) { 1792 MachineModuleInfoCOFF &MMICOFF = 1793 MMI->getObjFileInfo<MachineModuleInfoCOFF>(); 1794 1795 // Output stubs for external and common global variables. 1796 MachineModuleInfoCOFF::SymbolListTy Stubs = MMICOFF.GetGVStubList(); 1797 if (!Stubs.empty()) { 1798 const DataLayout &DL = M.getDataLayout(); 1799 1800 for (const auto &Stub : Stubs) { 1801 SmallString<256> SectionName = StringRef(".rdata$"); 1802 SectionName += Stub.first->getName(); 1803 OutStreamer->SwitchSection(OutContext.getCOFFSection( 1804 SectionName, 1805 COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | COFF::IMAGE_SCN_MEM_READ | 1806 COFF::IMAGE_SCN_LNK_COMDAT, 1807 SectionKind::getReadOnly(), Stub.first->getName(), 1808 COFF::IMAGE_COMDAT_SELECT_ANY)); 1809 emitAlignment(Align(DL.getPointerSize())); 1810 OutStreamer->emitSymbolAttribute(Stub.first, MCSA_Global); 1811 OutStreamer->emitLabel(Stub.first); 1812 OutStreamer->emitSymbolValue(Stub.second.getPointer(), 1813 DL.getPointerSize()); 1814 } 1815 } 1816 } 1817 1818 // Finalize debug and EH information. 1819 for (const HandlerInfo &HI : Handlers) { 1820 NamedRegionTimer T(HI.TimerName, HI.TimerDescription, HI.TimerGroupName, 1821 HI.TimerGroupDescription, TimePassesIsEnabled); 1822 HI.Handler->endModule(); 1823 } 1824 1825 // This deletes all the ephemeral handlers that AsmPrinter added, while 1826 // keeping all the user-added handlers alive until the AsmPrinter is 1827 // destroyed. 1828 Handlers.erase(Handlers.begin() + NumUserHandlers, Handlers.end()); 1829 DD = nullptr; 1830 1831 // If the target wants to know about weak references, print them all. 1832 if (MAI->getWeakRefDirective()) { 1833 // FIXME: This is not lazy, it would be nice to only print weak references 1834 // to stuff that is actually used. Note that doing so would require targets 1835 // to notice uses in operands (due to constant exprs etc). This should 1836 // happen with the MC stuff eventually. 1837 1838 // Print out module-level global objects here. 1839 for (const auto &GO : M.global_objects()) { 1840 if (!GO.hasExternalWeakLinkage()) 1841 continue; 1842 OutStreamer->emitSymbolAttribute(getSymbol(&GO), MCSA_WeakReference); 1843 } 1844 } 1845 1846 // Print aliases in topological order, that is, for each alias a = b, 1847 // b must be printed before a. 1848 // This is because on some targets (e.g. PowerPC) linker expects aliases in 1849 // such an order to generate correct TOC information. 1850 SmallVector<const GlobalAlias *, 16> AliasStack; 1851 SmallPtrSet<const GlobalAlias *, 16> AliasVisited; 1852 for (const auto &Alias : M.aliases()) { 1853 for (const GlobalAlias *Cur = &Alias; Cur; 1854 Cur = dyn_cast<GlobalAlias>(Cur->getAliasee())) { 1855 if (!AliasVisited.insert(Cur).second) 1856 break; 1857 AliasStack.push_back(Cur); 1858 } 1859 for (const GlobalAlias *AncestorAlias : llvm::reverse(AliasStack)) 1860 emitGlobalIndirectSymbol(M, *AncestorAlias); 1861 AliasStack.clear(); 1862 } 1863 for (const auto &IFunc : M.ifuncs()) 1864 emitGlobalIndirectSymbol(M, IFunc); 1865 1866 GCModuleInfo *MI = getAnalysisIfAvailable<GCModuleInfo>(); 1867 assert(MI && "AsmPrinter didn't require GCModuleInfo?"); 1868 for (GCModuleInfo::iterator I = MI->end(), E = MI->begin(); I != E; ) 1869 if (GCMetadataPrinter *MP = GetOrCreateGCPrinter(**--I)) 1870 MP->finishAssembly(M, *MI, *this); 1871 1872 // Emit llvm.ident metadata in an '.ident' directive. 1873 emitModuleIdents(M); 1874 1875 // Emit bytes for llvm.commandline metadata. 1876 emitModuleCommandLines(M); 1877 1878 // Emit __morestack address if needed for indirect calls. 1879 if (MMI->usesMorestackAddr()) { 1880 Align Alignment(1); 1881 MCSection *ReadOnlySection = getObjFileLowering().getSectionForConstant( 1882 getDataLayout(), SectionKind::getReadOnly(), 1883 /*C=*/nullptr, Alignment); 1884 OutStreamer->SwitchSection(ReadOnlySection); 1885 1886 MCSymbol *AddrSymbol = 1887 OutContext.getOrCreateSymbol(StringRef("__morestack_addr")); 1888 OutStreamer->emitLabel(AddrSymbol); 1889 1890 unsigned PtrSize = MAI->getCodePointerSize(); 1891 OutStreamer->emitSymbolValue(GetExternalSymbolSymbol("__morestack"), 1892 PtrSize); 1893 } 1894 1895 // Emit .note.GNU-split-stack and .note.GNU-no-split-stack sections if 1896 // split-stack is used. 1897 if (TM.getTargetTriple().isOSBinFormatELF() && MMI->hasSplitStack()) { 1898 OutStreamer->SwitchSection( 1899 OutContext.getELFSection(".note.GNU-split-stack", ELF::SHT_PROGBITS, 0)); 1900 if (MMI->hasNosplitStack()) 1901 OutStreamer->SwitchSection( 1902 OutContext.getELFSection(".note.GNU-no-split-stack", ELF::SHT_PROGBITS, 0)); 1903 } 1904 1905 // If we don't have any trampolines, then we don't require stack memory 1906 // to be executable. Some targets have a directive to declare this. 1907 Function *InitTrampolineIntrinsic = M.getFunction("llvm.init.trampoline"); 1908 if (!InitTrampolineIntrinsic || InitTrampolineIntrinsic->use_empty()) 1909 if (MCSection *S = MAI->getNonexecutableStackSection(OutContext)) 1910 OutStreamer->SwitchSection(S); 1911 1912 if (TM.Options.EmitAddrsig) { 1913 // Emit address-significance attributes for all globals. 1914 OutStreamer->emitAddrsig(); 1915 for (const GlobalValue &GV : M.global_values()) { 1916 if (!GV.use_empty() && !GV.isTransitiveUsedByMetadataOnly() && 1917 !GV.isThreadLocal() && !GV.hasDLLImportStorageClass() && 1918 !GV.getName().startswith("llvm.") && !GV.hasAtLeastLocalUnnamedAddr()) 1919 OutStreamer->emitAddrsigSym(getSymbol(&GV)); 1920 } 1921 } 1922 1923 // Emit symbol partition specifications (ELF only). 1924 if (TM.getTargetTriple().isOSBinFormatELF()) { 1925 unsigned UniqueID = 0; 1926 for (const GlobalValue &GV : M.global_values()) { 1927 if (!GV.hasPartition() || GV.isDeclarationForLinker() || 1928 GV.getVisibility() != GlobalValue::DefaultVisibility) 1929 continue; 1930 1931 OutStreamer->SwitchSection( 1932 OutContext.getELFSection(".llvm_sympart", ELF::SHT_LLVM_SYMPART, 0, 0, 1933 "", false, ++UniqueID, nullptr)); 1934 OutStreamer->emitBytes(GV.getPartition()); 1935 OutStreamer->emitZeros(1); 1936 OutStreamer->emitValue( 1937 MCSymbolRefExpr::create(getSymbol(&GV), OutContext), 1938 MAI->getCodePointerSize()); 1939 } 1940 } 1941 1942 // Allow the target to emit any magic that it wants at the end of the file, 1943 // after everything else has gone out. 1944 emitEndOfAsmFile(M); 1945 1946 MMI = nullptr; 1947 1948 OutStreamer->Finish(); 1949 OutStreamer->reset(); 1950 OwnedMLI.reset(); 1951 OwnedMDT.reset(); 1952 1953 return false; 1954 } 1955 1956 MCSymbol *AsmPrinter::getMBBExceptionSym(const MachineBasicBlock &MBB) { 1957 auto Res = MBBSectionExceptionSyms.try_emplace(MBB.getSectionIDNum()); 1958 if (Res.second) 1959 Res.first->second = createTempSymbol("exception"); 1960 return Res.first->second; 1961 } 1962 1963 void AsmPrinter::SetupMachineFunction(MachineFunction &MF) { 1964 this->MF = &MF; 1965 const Function &F = MF.getFunction(); 1966 1967 // Get the function symbol. 1968 if (!MAI->needsFunctionDescriptors()) { 1969 CurrentFnSym = getSymbol(&MF.getFunction()); 1970 } else { 1971 assert(TM.getTargetTriple().isOSAIX() && 1972 "Only AIX uses the function descriptor hooks."); 1973 // AIX is unique here in that the name of the symbol emitted for the 1974 // function body does not have the same name as the source function's 1975 // C-linkage name. 1976 assert(CurrentFnDescSym && "The function descriptor symbol needs to be" 1977 " initalized first."); 1978 1979 // Get the function entry point symbol. 1980 CurrentFnSym = getObjFileLowering().getFunctionEntryPointSymbol(&F, TM); 1981 } 1982 1983 CurrentFnSymForSize = CurrentFnSym; 1984 CurrentFnBegin = nullptr; 1985 CurrentSectionBeginSym = nullptr; 1986 MBBSectionRanges.clear(); 1987 MBBSectionExceptionSyms.clear(); 1988 bool NeedsLocalForSize = MAI->needsLocalForSize(); 1989 if (F.hasFnAttribute("patchable-function-entry") || 1990 F.hasFnAttribute("function-instrument") || 1991 F.hasFnAttribute("xray-instruction-threshold") || 1992 needFuncLabelsForEHOrDebugInfo(MF) || NeedsLocalForSize || 1993 MF.getTarget().Options.EmitStackSizeSection || MF.hasBBLabels()) { 1994 CurrentFnBegin = createTempSymbol("func_begin"); 1995 if (NeedsLocalForSize) 1996 CurrentFnSymForSize = CurrentFnBegin; 1997 } 1998 1999 ORE = &getAnalysis<MachineOptimizationRemarkEmitterPass>().getORE(); 2000 } 2001 2002 namespace { 2003 2004 // Keep track the alignment, constpool entries per Section. 2005 struct SectionCPs { 2006 MCSection *S; 2007 Align Alignment; 2008 SmallVector<unsigned, 4> CPEs; 2009 2010 SectionCPs(MCSection *s, Align a) : S(s), Alignment(a) {} 2011 }; 2012 2013 } // end anonymous namespace 2014 2015 /// EmitConstantPool - Print to the current output stream assembly 2016 /// representations of the constants in the constant pool MCP. This is 2017 /// used to print out constants which have been "spilled to memory" by 2018 /// the code generator. 2019 void AsmPrinter::emitConstantPool() { 2020 const MachineConstantPool *MCP = MF->getConstantPool(); 2021 const std::vector<MachineConstantPoolEntry> &CP = MCP->getConstants(); 2022 if (CP.empty()) return; 2023 2024 // Calculate sections for constant pool entries. We collect entries to go into 2025 // the same section together to reduce amount of section switch statements. 2026 SmallVector<SectionCPs, 4> CPSections; 2027 for (unsigned i = 0, e = CP.size(); i != e; ++i) { 2028 const MachineConstantPoolEntry &CPE = CP[i]; 2029 Align Alignment = CPE.getAlign(); 2030 2031 SectionKind Kind = CPE.getSectionKind(&getDataLayout()); 2032 2033 const Constant *C = nullptr; 2034 if (!CPE.isMachineConstantPoolEntry()) 2035 C = CPE.Val.ConstVal; 2036 2037 MCSection *S = getObjFileLowering().getSectionForConstant( 2038 getDataLayout(), Kind, C, Alignment); 2039 2040 // The number of sections are small, just do a linear search from the 2041 // last section to the first. 2042 bool Found = false; 2043 unsigned SecIdx = CPSections.size(); 2044 while (SecIdx != 0) { 2045 if (CPSections[--SecIdx].S == S) { 2046 Found = true; 2047 break; 2048 } 2049 } 2050 if (!Found) { 2051 SecIdx = CPSections.size(); 2052 CPSections.push_back(SectionCPs(S, Alignment)); 2053 } 2054 2055 if (Alignment > CPSections[SecIdx].Alignment) 2056 CPSections[SecIdx].Alignment = Alignment; 2057 CPSections[SecIdx].CPEs.push_back(i); 2058 } 2059 2060 // Now print stuff into the calculated sections. 2061 const MCSection *CurSection = nullptr; 2062 unsigned Offset = 0; 2063 for (unsigned i = 0, e = CPSections.size(); i != e; ++i) { 2064 for (unsigned j = 0, ee = CPSections[i].CPEs.size(); j != ee; ++j) { 2065 unsigned CPI = CPSections[i].CPEs[j]; 2066 MCSymbol *Sym = GetCPISymbol(CPI); 2067 if (!Sym->isUndefined()) 2068 continue; 2069 2070 if (CurSection != CPSections[i].S) { 2071 OutStreamer->SwitchSection(CPSections[i].S); 2072 emitAlignment(Align(CPSections[i].Alignment)); 2073 CurSection = CPSections[i].S; 2074 Offset = 0; 2075 } 2076 2077 MachineConstantPoolEntry CPE = CP[CPI]; 2078 2079 // Emit inter-object padding for alignment. 2080 unsigned NewOffset = alignTo(Offset, CPE.getAlign()); 2081 OutStreamer->emitZeros(NewOffset - Offset); 2082 2083 Offset = NewOffset + CPE.getSizeInBytes(getDataLayout()); 2084 2085 OutStreamer->emitLabel(Sym); 2086 if (CPE.isMachineConstantPoolEntry()) 2087 emitMachineConstantPoolValue(CPE.Val.MachineCPVal); 2088 else 2089 emitGlobalConstant(getDataLayout(), CPE.Val.ConstVal); 2090 } 2091 } 2092 } 2093 2094 // Print assembly representations of the jump tables used by the current 2095 // function. 2096 void AsmPrinter::emitJumpTableInfo() { 2097 const DataLayout &DL = MF->getDataLayout(); 2098 const MachineJumpTableInfo *MJTI = MF->getJumpTableInfo(); 2099 if (!MJTI) return; 2100 if (MJTI->getEntryKind() == MachineJumpTableInfo::EK_Inline) return; 2101 const std::vector<MachineJumpTableEntry> &JT = MJTI->getJumpTables(); 2102 if (JT.empty()) return; 2103 2104 // Pick the directive to use to print the jump table entries, and switch to 2105 // the appropriate section. 2106 const Function &F = MF->getFunction(); 2107 const TargetLoweringObjectFile &TLOF = getObjFileLowering(); 2108 bool JTInDiffSection = !TLOF.shouldPutJumpTableInFunctionSection( 2109 MJTI->getEntryKind() == MachineJumpTableInfo::EK_LabelDifference32, 2110 F); 2111 if (JTInDiffSection) { 2112 // Drop it in the readonly section. 2113 MCSection *ReadOnlySection = TLOF.getSectionForJumpTable(F, TM); 2114 OutStreamer->SwitchSection(ReadOnlySection); 2115 } 2116 2117 emitAlignment(Align(MJTI->getEntryAlignment(DL))); 2118 2119 // Jump tables in code sections are marked with a data_region directive 2120 // where that's supported. 2121 if (!JTInDiffSection) 2122 OutStreamer->emitDataRegion(MCDR_DataRegionJT32); 2123 2124 for (unsigned JTI = 0, e = JT.size(); JTI != e; ++JTI) { 2125 const std::vector<MachineBasicBlock*> &JTBBs = JT[JTI].MBBs; 2126 2127 // If this jump table was deleted, ignore it. 2128 if (JTBBs.empty()) continue; 2129 2130 // For the EK_LabelDifference32 entry, if using .set avoids a relocation, 2131 /// emit a .set directive for each unique entry. 2132 if (MJTI->getEntryKind() == MachineJumpTableInfo::EK_LabelDifference32 && 2133 MAI->doesSetDirectiveSuppressReloc()) { 2134 SmallPtrSet<const MachineBasicBlock*, 16> EmittedSets; 2135 const TargetLowering *TLI = MF->getSubtarget().getTargetLowering(); 2136 const MCExpr *Base = TLI->getPICJumpTableRelocBaseExpr(MF,JTI,OutContext); 2137 for (unsigned ii = 0, ee = JTBBs.size(); ii != ee; ++ii) { 2138 const MachineBasicBlock *MBB = JTBBs[ii]; 2139 if (!EmittedSets.insert(MBB).second) 2140 continue; 2141 2142 // .set LJTSet, LBB32-base 2143 const MCExpr *LHS = 2144 MCSymbolRefExpr::create(MBB->getSymbol(), OutContext); 2145 OutStreamer->emitAssignment(GetJTSetSymbol(JTI, MBB->getNumber()), 2146 MCBinaryExpr::createSub(LHS, Base, 2147 OutContext)); 2148 } 2149 } 2150 2151 // On some targets (e.g. Darwin) we want to emit two consecutive labels 2152 // before each jump table. The first label is never referenced, but tells 2153 // the assembler and linker the extents of the jump table object. The 2154 // second label is actually referenced by the code. 2155 if (JTInDiffSection && DL.hasLinkerPrivateGlobalPrefix()) 2156 // FIXME: This doesn't have to have any specific name, just any randomly 2157 // named and numbered local label started with 'l' would work. Simplify 2158 // GetJTISymbol. 2159 OutStreamer->emitLabel(GetJTISymbol(JTI, true)); 2160 2161 MCSymbol* JTISymbol = GetJTISymbol(JTI); 2162 OutStreamer->emitLabel(JTISymbol); 2163 2164 for (unsigned ii = 0, ee = JTBBs.size(); ii != ee; ++ii) 2165 emitJumpTableEntry(MJTI, JTBBs[ii], JTI); 2166 } 2167 if (!JTInDiffSection) 2168 OutStreamer->emitDataRegion(MCDR_DataRegionEnd); 2169 } 2170 2171 /// EmitJumpTableEntry - Emit a jump table entry for the specified MBB to the 2172 /// current stream. 2173 void AsmPrinter::emitJumpTableEntry(const MachineJumpTableInfo *MJTI, 2174 const MachineBasicBlock *MBB, 2175 unsigned UID) const { 2176 assert(MBB && MBB->getNumber() >= 0 && "Invalid basic block"); 2177 const MCExpr *Value = nullptr; 2178 switch (MJTI->getEntryKind()) { 2179 case MachineJumpTableInfo::EK_Inline: 2180 llvm_unreachable("Cannot emit EK_Inline jump table entry"); 2181 case MachineJumpTableInfo::EK_Custom32: 2182 Value = MF->getSubtarget().getTargetLowering()->LowerCustomJumpTableEntry( 2183 MJTI, MBB, UID, OutContext); 2184 break; 2185 case MachineJumpTableInfo::EK_BlockAddress: 2186 // EK_BlockAddress - Each entry is a plain address of block, e.g.: 2187 // .word LBB123 2188 Value = MCSymbolRefExpr::create(MBB->getSymbol(), OutContext); 2189 break; 2190 case MachineJumpTableInfo::EK_GPRel32BlockAddress: { 2191 // EK_GPRel32BlockAddress - Each entry is an address of block, encoded 2192 // with a relocation as gp-relative, e.g.: 2193 // .gprel32 LBB123 2194 MCSymbol *MBBSym = MBB->getSymbol(); 2195 OutStreamer->emitGPRel32Value(MCSymbolRefExpr::create(MBBSym, OutContext)); 2196 return; 2197 } 2198 2199 case MachineJumpTableInfo::EK_GPRel64BlockAddress: { 2200 // EK_GPRel64BlockAddress - Each entry is an address of block, encoded 2201 // with a relocation as gp-relative, e.g.: 2202 // .gpdword LBB123 2203 MCSymbol *MBBSym = MBB->getSymbol(); 2204 OutStreamer->emitGPRel64Value(MCSymbolRefExpr::create(MBBSym, OutContext)); 2205 return; 2206 } 2207 2208 case MachineJumpTableInfo::EK_LabelDifference32: { 2209 // Each entry is the address of the block minus the address of the jump 2210 // table. This is used for PIC jump tables where gprel32 is not supported. 2211 // e.g.: 2212 // .word LBB123 - LJTI1_2 2213 // If the .set directive avoids relocations, this is emitted as: 2214 // .set L4_5_set_123, LBB123 - LJTI1_2 2215 // .word L4_5_set_123 2216 if (MAI->doesSetDirectiveSuppressReloc()) { 2217 Value = MCSymbolRefExpr::create(GetJTSetSymbol(UID, MBB->getNumber()), 2218 OutContext); 2219 break; 2220 } 2221 Value = MCSymbolRefExpr::create(MBB->getSymbol(), OutContext); 2222 const TargetLowering *TLI = MF->getSubtarget().getTargetLowering(); 2223 const MCExpr *Base = TLI->getPICJumpTableRelocBaseExpr(MF, UID, OutContext); 2224 Value = MCBinaryExpr::createSub(Value, Base, OutContext); 2225 break; 2226 } 2227 } 2228 2229 assert(Value && "Unknown entry kind!"); 2230 2231 unsigned EntrySize = MJTI->getEntrySize(getDataLayout()); 2232 OutStreamer->emitValue(Value, EntrySize); 2233 } 2234 2235 /// EmitSpecialLLVMGlobal - Check to see if the specified global is a 2236 /// special global used by LLVM. If so, emit it and return true, otherwise 2237 /// do nothing and return false. 2238 bool AsmPrinter::emitSpecialLLVMGlobal(const GlobalVariable *GV) { 2239 if (GV->getName() == "llvm.used") { 2240 if (MAI->hasNoDeadStrip()) // No need to emit this at all. 2241 emitLLVMUsedList(cast<ConstantArray>(GV->getInitializer())); 2242 return true; 2243 } 2244 2245 // Ignore debug and non-emitted data. This handles llvm.compiler.used. 2246 if (GV->getSection() == "llvm.metadata" || 2247 GV->hasAvailableExternallyLinkage()) 2248 return true; 2249 2250 if (!GV->hasAppendingLinkage()) return false; 2251 2252 assert(GV->hasInitializer() && "Not a special LLVM global!"); 2253 2254 if (GV->getName() == "llvm.global_ctors") { 2255 emitXXStructorList(GV->getParent()->getDataLayout(), GV->getInitializer(), 2256 /* isCtor */ true); 2257 2258 return true; 2259 } 2260 2261 if (GV->getName() == "llvm.global_dtors") { 2262 emitXXStructorList(GV->getParent()->getDataLayout(), GV->getInitializer(), 2263 /* isCtor */ false); 2264 2265 return true; 2266 } 2267 2268 report_fatal_error("unknown special variable"); 2269 } 2270 2271 /// EmitLLVMUsedList - For targets that define a MAI::UsedDirective, mark each 2272 /// global in the specified llvm.used list. 2273 void AsmPrinter::emitLLVMUsedList(const ConstantArray *InitList) { 2274 // Should be an array of 'i8*'. 2275 for (unsigned i = 0, e = InitList->getNumOperands(); i != e; ++i) { 2276 const GlobalValue *GV = 2277 dyn_cast<GlobalValue>(InitList->getOperand(i)->stripPointerCasts()); 2278 if (GV) 2279 OutStreamer->emitSymbolAttribute(getSymbol(GV), MCSA_NoDeadStrip); 2280 } 2281 } 2282 2283 void AsmPrinter::preprocessXXStructorList(const DataLayout &DL, 2284 const Constant *List, 2285 SmallVector<Structor, 8> &Structors) { 2286 // Should be an array of '{ i32, void ()*, i8* }' structs. The first value is 2287 // the init priority. 2288 if (!isa<ConstantArray>(List)) 2289 return; 2290 2291 // Gather the structors in a form that's convenient for sorting by priority. 2292 for (Value *O : cast<ConstantArray>(List)->operands()) { 2293 auto *CS = cast<ConstantStruct>(O); 2294 if (CS->getOperand(1)->isNullValue()) 2295 break; // Found a null terminator, skip the rest. 2296 ConstantInt *Priority = dyn_cast<ConstantInt>(CS->getOperand(0)); 2297 if (!Priority) 2298 continue; // Malformed. 2299 Structors.push_back(Structor()); 2300 Structor &S = Structors.back(); 2301 S.Priority = Priority->getLimitedValue(65535); 2302 S.Func = CS->getOperand(1); 2303 if (!CS->getOperand(2)->isNullValue()) { 2304 if (TM.getTargetTriple().isOSAIX()) 2305 llvm::report_fatal_error( 2306 "associated data of XXStructor list is not yet supported on AIX"); 2307 S.ComdatKey = 2308 dyn_cast<GlobalValue>(CS->getOperand(2)->stripPointerCasts()); 2309 } 2310 } 2311 2312 // Emit the function pointers in the target-specific order 2313 llvm::stable_sort(Structors, [](const Structor &L, const Structor &R) { 2314 return L.Priority < R.Priority; 2315 }); 2316 } 2317 2318 /// EmitXXStructorList - Emit the ctor or dtor list taking into account the init 2319 /// priority. 2320 void AsmPrinter::emitXXStructorList(const DataLayout &DL, const Constant *List, 2321 bool IsCtor) { 2322 SmallVector<Structor, 8> Structors; 2323 preprocessXXStructorList(DL, List, Structors); 2324 if (Structors.empty()) 2325 return; 2326 2327 // Emit the structors in reverse order if we are using the .ctor/.dtor 2328 // initialization scheme. 2329 if (!TM.Options.UseInitArray) 2330 std::reverse(Structors.begin(), Structors.end()); 2331 2332 const Align Align = DL.getPointerPrefAlignment(); 2333 for (Structor &S : Structors) { 2334 const TargetLoweringObjectFile &Obj = getObjFileLowering(); 2335 const MCSymbol *KeySym = nullptr; 2336 if (GlobalValue *GV = S.ComdatKey) { 2337 if (GV->isDeclarationForLinker()) 2338 // If the associated variable is not defined in this module 2339 // (it might be available_externally, or have been an 2340 // available_externally definition that was dropped by the 2341 // EliminateAvailableExternally pass), some other TU 2342 // will provide its dynamic initializer. 2343 continue; 2344 2345 KeySym = getSymbol(GV); 2346 } 2347 2348 MCSection *OutputSection = 2349 (IsCtor ? Obj.getStaticCtorSection(S.Priority, KeySym) 2350 : Obj.getStaticDtorSection(S.Priority, KeySym)); 2351 OutStreamer->SwitchSection(OutputSection); 2352 if (OutStreamer->getCurrentSection() != OutStreamer->getPreviousSection()) 2353 emitAlignment(Align); 2354 emitXXStructor(DL, S.Func); 2355 } 2356 } 2357 2358 void AsmPrinter::emitModuleIdents(Module &M) { 2359 if (!MAI->hasIdentDirective()) 2360 return; 2361 2362 if (const NamedMDNode *NMD = M.getNamedMetadata("llvm.ident")) { 2363 for (unsigned i = 0, e = NMD->getNumOperands(); i != e; ++i) { 2364 const MDNode *N = NMD->getOperand(i); 2365 assert(N->getNumOperands() == 1 && 2366 "llvm.ident metadata entry can have only one operand"); 2367 const MDString *S = cast<MDString>(N->getOperand(0)); 2368 OutStreamer->emitIdent(S->getString()); 2369 } 2370 } 2371 } 2372 2373 void AsmPrinter::emitModuleCommandLines(Module &M) { 2374 MCSection *CommandLine = getObjFileLowering().getSectionForCommandLines(); 2375 if (!CommandLine) 2376 return; 2377 2378 const NamedMDNode *NMD = M.getNamedMetadata("llvm.commandline"); 2379 if (!NMD || !NMD->getNumOperands()) 2380 return; 2381 2382 OutStreamer->PushSection(); 2383 OutStreamer->SwitchSection(CommandLine); 2384 OutStreamer->emitZeros(1); 2385 for (unsigned i = 0, e = NMD->getNumOperands(); i != e; ++i) { 2386 const MDNode *N = NMD->getOperand(i); 2387 assert(N->getNumOperands() == 1 && 2388 "llvm.commandline metadata entry can have only one operand"); 2389 const MDString *S = cast<MDString>(N->getOperand(0)); 2390 OutStreamer->emitBytes(S->getString()); 2391 OutStreamer->emitZeros(1); 2392 } 2393 OutStreamer->PopSection(); 2394 } 2395 2396 //===--------------------------------------------------------------------===// 2397 // Emission and print routines 2398 // 2399 2400 /// Emit a byte directive and value. 2401 /// 2402 void AsmPrinter::emitInt8(int Value) const { OutStreamer->emitInt8(Value); } 2403 2404 /// Emit a short directive and value. 2405 void AsmPrinter::emitInt16(int Value) const { OutStreamer->emitInt16(Value); } 2406 2407 /// Emit a long directive and value. 2408 void AsmPrinter::emitInt32(int Value) const { OutStreamer->emitInt32(Value); } 2409 2410 /// Emit a long long directive and value. 2411 void AsmPrinter::emitInt64(uint64_t Value) const { 2412 OutStreamer->emitInt64(Value); 2413 } 2414 2415 /// Emit something like ".long Hi-Lo" where the size in bytes of the directive 2416 /// is specified by Size and Hi/Lo specify the labels. This implicitly uses 2417 /// .set if it avoids relocations. 2418 void AsmPrinter::emitLabelDifference(const MCSymbol *Hi, const MCSymbol *Lo, 2419 unsigned Size) const { 2420 OutStreamer->emitAbsoluteSymbolDiff(Hi, Lo, Size); 2421 } 2422 2423 /// EmitLabelPlusOffset - Emit something like ".long Label+Offset" 2424 /// where the size in bytes of the directive is specified by Size and Label 2425 /// specifies the label. This implicitly uses .set if it is available. 2426 void AsmPrinter::emitLabelPlusOffset(const MCSymbol *Label, uint64_t Offset, 2427 unsigned Size, 2428 bool IsSectionRelative) const { 2429 if (MAI->needsDwarfSectionOffsetDirective() && IsSectionRelative) { 2430 OutStreamer->EmitCOFFSecRel32(Label, Offset); 2431 if (Size > 4) 2432 OutStreamer->emitZeros(Size - 4); 2433 return; 2434 } 2435 2436 // Emit Label+Offset (or just Label if Offset is zero) 2437 const MCExpr *Expr = MCSymbolRefExpr::create(Label, OutContext); 2438 if (Offset) 2439 Expr = MCBinaryExpr::createAdd( 2440 Expr, MCConstantExpr::create(Offset, OutContext), OutContext); 2441 2442 OutStreamer->emitValue(Expr, Size); 2443 } 2444 2445 //===----------------------------------------------------------------------===// 2446 2447 // EmitAlignment - Emit an alignment directive to the specified power of 2448 // two boundary. If a global value is specified, and if that global has 2449 // an explicit alignment requested, it will override the alignment request 2450 // if required for correctness. 2451 void AsmPrinter::emitAlignment(Align Alignment, const GlobalObject *GV) const { 2452 if (GV) 2453 Alignment = getGVAlignment(GV, GV->getParent()->getDataLayout(), Alignment); 2454 2455 if (Alignment == Align(1)) 2456 return; // 1-byte aligned: no need to emit alignment. 2457 2458 if (getCurrentSection()->getKind().isText()) 2459 OutStreamer->emitCodeAlignment(Alignment.value()); 2460 else 2461 OutStreamer->emitValueToAlignment(Alignment.value()); 2462 } 2463 2464 //===----------------------------------------------------------------------===// 2465 // Constant emission. 2466 //===----------------------------------------------------------------------===// 2467 2468 const MCExpr *AsmPrinter::lowerConstant(const Constant *CV) { 2469 MCContext &Ctx = OutContext; 2470 2471 if (CV->isNullValue() || isa<UndefValue>(CV)) 2472 return MCConstantExpr::create(0, Ctx); 2473 2474 if (const ConstantInt *CI = dyn_cast<ConstantInt>(CV)) 2475 return MCConstantExpr::create(CI->getZExtValue(), Ctx); 2476 2477 if (const GlobalValue *GV = dyn_cast<GlobalValue>(CV)) 2478 return MCSymbolRefExpr::create(getSymbol(GV), Ctx); 2479 2480 if (const BlockAddress *BA = dyn_cast<BlockAddress>(CV)) 2481 return MCSymbolRefExpr::create(GetBlockAddressSymbol(BA), Ctx); 2482 2483 if (const auto *Equiv = dyn_cast<DSOLocalEquivalent>(CV)) 2484 return getObjFileLowering().lowerDSOLocalEquivalent(Equiv, TM); 2485 2486 const ConstantExpr *CE = dyn_cast<ConstantExpr>(CV); 2487 if (!CE) { 2488 llvm_unreachable("Unknown constant value to lower!"); 2489 } 2490 2491 switch (CE->getOpcode()) { 2492 case Instruction::AddrSpaceCast: { 2493 const Constant *Op = CE->getOperand(0); 2494 unsigned DstAS = CE->getType()->getPointerAddressSpace(); 2495 unsigned SrcAS = Op->getType()->getPointerAddressSpace(); 2496 if (TM.isNoopAddrSpaceCast(SrcAS, DstAS)) 2497 return lowerConstant(Op); 2498 2499 // Fallthrough to error. 2500 LLVM_FALLTHROUGH; 2501 } 2502 default: { 2503 // If the code isn't optimized, there may be outstanding folding 2504 // opportunities. Attempt to fold the expression using DataLayout as a 2505 // last resort before giving up. 2506 Constant *C = ConstantFoldConstant(CE, getDataLayout()); 2507 if (C != CE) 2508 return lowerConstant(C); 2509 2510 // Otherwise report the problem to the user. 2511 std::string S; 2512 raw_string_ostream OS(S); 2513 OS << "Unsupported expression in static initializer: "; 2514 CE->printAsOperand(OS, /*PrintType=*/false, 2515 !MF ? nullptr : MF->getFunction().getParent()); 2516 report_fatal_error(OS.str()); 2517 } 2518 case Instruction::GetElementPtr: { 2519 // Generate a symbolic expression for the byte address 2520 APInt OffsetAI(getDataLayout().getPointerTypeSizeInBits(CE->getType()), 0); 2521 cast<GEPOperator>(CE)->accumulateConstantOffset(getDataLayout(), OffsetAI); 2522 2523 const MCExpr *Base = lowerConstant(CE->getOperand(0)); 2524 if (!OffsetAI) 2525 return Base; 2526 2527 int64_t Offset = OffsetAI.getSExtValue(); 2528 return MCBinaryExpr::createAdd(Base, MCConstantExpr::create(Offset, Ctx), 2529 Ctx); 2530 } 2531 2532 case Instruction::Trunc: 2533 // We emit the value and depend on the assembler to truncate the generated 2534 // expression properly. This is important for differences between 2535 // blockaddress labels. Since the two labels are in the same function, it 2536 // is reasonable to treat their delta as a 32-bit value. 2537 LLVM_FALLTHROUGH; 2538 case Instruction::BitCast: 2539 return lowerConstant(CE->getOperand(0)); 2540 2541 case Instruction::IntToPtr: { 2542 const DataLayout &DL = getDataLayout(); 2543 2544 // Handle casts to pointers by changing them into casts to the appropriate 2545 // integer type. This promotes constant folding and simplifies this code. 2546 Constant *Op = CE->getOperand(0); 2547 Op = ConstantExpr::getIntegerCast(Op, DL.getIntPtrType(CV->getType()), 2548 false/*ZExt*/); 2549 return lowerConstant(Op); 2550 } 2551 2552 case Instruction::PtrToInt: { 2553 const DataLayout &DL = getDataLayout(); 2554 2555 // Support only foldable casts to/from pointers that can be eliminated by 2556 // changing the pointer to the appropriately sized integer type. 2557 Constant *Op = CE->getOperand(0); 2558 Type *Ty = CE->getType(); 2559 2560 const MCExpr *OpExpr = lowerConstant(Op); 2561 2562 // We can emit the pointer value into this slot if the slot is an 2563 // integer slot equal to the size of the pointer. 2564 // 2565 // If the pointer is larger than the resultant integer, then 2566 // as with Trunc just depend on the assembler to truncate it. 2567 if (DL.getTypeAllocSize(Ty).getFixedSize() <= 2568 DL.getTypeAllocSize(Op->getType()).getFixedSize()) 2569 return OpExpr; 2570 2571 // Otherwise the pointer is smaller than the resultant integer, mask off 2572 // the high bits so we are sure to get a proper truncation if the input is 2573 // a constant expr. 2574 unsigned InBits = DL.getTypeAllocSizeInBits(Op->getType()); 2575 const MCExpr *MaskExpr = MCConstantExpr::create(~0ULL >> (64-InBits), Ctx); 2576 return MCBinaryExpr::createAnd(OpExpr, MaskExpr, Ctx); 2577 } 2578 2579 case Instruction::Sub: { 2580 GlobalValue *LHSGV; 2581 APInt LHSOffset; 2582 DSOLocalEquivalent *DSOEquiv; 2583 if (IsConstantOffsetFromGlobal(CE->getOperand(0), LHSGV, LHSOffset, 2584 getDataLayout(), &DSOEquiv)) { 2585 GlobalValue *RHSGV; 2586 APInt RHSOffset; 2587 if (IsConstantOffsetFromGlobal(CE->getOperand(1), RHSGV, RHSOffset, 2588 getDataLayout())) { 2589 const MCExpr *RelocExpr = 2590 getObjFileLowering().lowerRelativeReference(LHSGV, RHSGV, TM); 2591 if (!RelocExpr) { 2592 const MCExpr *LHSExpr = 2593 MCSymbolRefExpr::create(getSymbol(LHSGV), Ctx); 2594 if (DSOEquiv && 2595 getObjFileLowering().supportDSOLocalEquivalentLowering()) 2596 LHSExpr = 2597 getObjFileLowering().lowerDSOLocalEquivalent(DSOEquiv, TM); 2598 RelocExpr = MCBinaryExpr::createSub( 2599 LHSExpr, MCSymbolRefExpr::create(getSymbol(RHSGV), Ctx), Ctx); 2600 } 2601 int64_t Addend = (LHSOffset - RHSOffset).getSExtValue(); 2602 if (Addend != 0) 2603 RelocExpr = MCBinaryExpr::createAdd( 2604 RelocExpr, MCConstantExpr::create(Addend, Ctx), Ctx); 2605 return RelocExpr; 2606 } 2607 } 2608 } 2609 // else fallthrough 2610 LLVM_FALLTHROUGH; 2611 2612 // The MC library also has a right-shift operator, but it isn't consistently 2613 // signed or unsigned between different targets. 2614 case Instruction::Add: 2615 case Instruction::Mul: 2616 case Instruction::SDiv: 2617 case Instruction::SRem: 2618 case Instruction::Shl: 2619 case Instruction::And: 2620 case Instruction::Or: 2621 case Instruction::Xor: { 2622 const MCExpr *LHS = lowerConstant(CE->getOperand(0)); 2623 const MCExpr *RHS = lowerConstant(CE->getOperand(1)); 2624 switch (CE->getOpcode()) { 2625 default: llvm_unreachable("Unknown binary operator constant cast expr"); 2626 case Instruction::Add: return MCBinaryExpr::createAdd(LHS, RHS, Ctx); 2627 case Instruction::Sub: return MCBinaryExpr::createSub(LHS, RHS, Ctx); 2628 case Instruction::Mul: return MCBinaryExpr::createMul(LHS, RHS, Ctx); 2629 case Instruction::SDiv: return MCBinaryExpr::createDiv(LHS, RHS, Ctx); 2630 case Instruction::SRem: return MCBinaryExpr::createMod(LHS, RHS, Ctx); 2631 case Instruction::Shl: return MCBinaryExpr::createShl(LHS, RHS, Ctx); 2632 case Instruction::And: return MCBinaryExpr::createAnd(LHS, RHS, Ctx); 2633 case Instruction::Or: return MCBinaryExpr::createOr (LHS, RHS, Ctx); 2634 case Instruction::Xor: return MCBinaryExpr::createXor(LHS, RHS, Ctx); 2635 } 2636 } 2637 } 2638 } 2639 2640 static void emitGlobalConstantImpl(const DataLayout &DL, const Constant *C, 2641 AsmPrinter &AP, 2642 const Constant *BaseCV = nullptr, 2643 uint64_t Offset = 0); 2644 2645 static void emitGlobalConstantFP(const ConstantFP *CFP, AsmPrinter &AP); 2646 static void emitGlobalConstantFP(APFloat APF, Type *ET, AsmPrinter &AP); 2647 2648 /// isRepeatedByteSequence - Determine whether the given value is 2649 /// composed of a repeated sequence of identical bytes and return the 2650 /// byte value. If it is not a repeated sequence, return -1. 2651 static int isRepeatedByteSequence(const ConstantDataSequential *V) { 2652 StringRef Data = V->getRawDataValues(); 2653 assert(!Data.empty() && "Empty aggregates should be CAZ node"); 2654 char C = Data[0]; 2655 for (unsigned i = 1, e = Data.size(); i != e; ++i) 2656 if (Data[i] != C) return -1; 2657 return static_cast<uint8_t>(C); // Ensure 255 is not returned as -1. 2658 } 2659 2660 /// isRepeatedByteSequence - Determine whether the given value is 2661 /// composed of a repeated sequence of identical bytes and return the 2662 /// byte value. If it is not a repeated sequence, return -1. 2663 static int isRepeatedByteSequence(const Value *V, const DataLayout &DL) { 2664 if (const ConstantInt *CI = dyn_cast<ConstantInt>(V)) { 2665 uint64_t Size = DL.getTypeAllocSizeInBits(V->getType()); 2666 assert(Size % 8 == 0); 2667 2668 // Extend the element to take zero padding into account. 2669 APInt Value = CI->getValue().zextOrSelf(Size); 2670 if (!Value.isSplat(8)) 2671 return -1; 2672 2673 return Value.zextOrTrunc(8).getZExtValue(); 2674 } 2675 if (const ConstantArray *CA = dyn_cast<ConstantArray>(V)) { 2676 // Make sure all array elements are sequences of the same repeated 2677 // byte. 2678 assert(CA->getNumOperands() != 0 && "Should be a CAZ"); 2679 Constant *Op0 = CA->getOperand(0); 2680 int Byte = isRepeatedByteSequence(Op0, DL); 2681 if (Byte == -1) 2682 return -1; 2683 2684 // All array elements must be equal. 2685 for (unsigned i = 1, e = CA->getNumOperands(); i != e; ++i) 2686 if (CA->getOperand(i) != Op0) 2687 return -1; 2688 return Byte; 2689 } 2690 2691 if (const ConstantDataSequential *CDS = dyn_cast<ConstantDataSequential>(V)) 2692 return isRepeatedByteSequence(CDS); 2693 2694 return -1; 2695 } 2696 2697 static void emitGlobalConstantDataSequential(const DataLayout &DL, 2698 const ConstantDataSequential *CDS, 2699 AsmPrinter &AP) { 2700 // See if we can aggregate this into a .fill, if so, emit it as such. 2701 int Value = isRepeatedByteSequence(CDS, DL); 2702 if (Value != -1) { 2703 uint64_t Bytes = DL.getTypeAllocSize(CDS->getType()); 2704 // Don't emit a 1-byte object as a .fill. 2705 if (Bytes > 1) 2706 return AP.OutStreamer->emitFill(Bytes, Value); 2707 } 2708 2709 // If this can be emitted with .ascii/.asciz, emit it as such. 2710 if (CDS->isString()) 2711 return AP.OutStreamer->emitBytes(CDS->getAsString()); 2712 2713 // Otherwise, emit the values in successive locations. 2714 unsigned ElementByteSize = CDS->getElementByteSize(); 2715 if (isa<IntegerType>(CDS->getElementType())) { 2716 for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i) { 2717 if (AP.isVerbose()) 2718 AP.OutStreamer->GetCommentOS() << format("0x%" PRIx64 "\n", 2719 CDS->getElementAsInteger(i)); 2720 AP.OutStreamer->emitIntValue(CDS->getElementAsInteger(i), 2721 ElementByteSize); 2722 } 2723 } else { 2724 Type *ET = CDS->getElementType(); 2725 for (unsigned I = 0, E = CDS->getNumElements(); I != E; ++I) 2726 emitGlobalConstantFP(CDS->getElementAsAPFloat(I), ET, AP); 2727 } 2728 2729 unsigned Size = DL.getTypeAllocSize(CDS->getType()); 2730 unsigned EmittedSize = 2731 DL.getTypeAllocSize(CDS->getElementType()) * CDS->getNumElements(); 2732 assert(EmittedSize <= Size && "Size cannot be less than EmittedSize!"); 2733 if (unsigned Padding = Size - EmittedSize) 2734 AP.OutStreamer->emitZeros(Padding); 2735 } 2736 2737 static void emitGlobalConstantArray(const DataLayout &DL, 2738 const ConstantArray *CA, AsmPrinter &AP, 2739 const Constant *BaseCV, uint64_t Offset) { 2740 // See if we can aggregate some values. Make sure it can be 2741 // represented as a series of bytes of the constant value. 2742 int Value = isRepeatedByteSequence(CA, DL); 2743 2744 if (Value != -1) { 2745 uint64_t Bytes = DL.getTypeAllocSize(CA->getType()); 2746 AP.OutStreamer->emitFill(Bytes, Value); 2747 } 2748 else { 2749 for (unsigned i = 0, e = CA->getNumOperands(); i != e; ++i) { 2750 emitGlobalConstantImpl(DL, CA->getOperand(i), AP, BaseCV, Offset); 2751 Offset += DL.getTypeAllocSize(CA->getOperand(i)->getType()); 2752 } 2753 } 2754 } 2755 2756 static void emitGlobalConstantVector(const DataLayout &DL, 2757 const ConstantVector *CV, AsmPrinter &AP) { 2758 for (unsigned i = 0, e = CV->getType()->getNumElements(); i != e; ++i) 2759 emitGlobalConstantImpl(DL, CV->getOperand(i), AP); 2760 2761 unsigned Size = DL.getTypeAllocSize(CV->getType()); 2762 unsigned EmittedSize = DL.getTypeAllocSize(CV->getType()->getElementType()) * 2763 CV->getType()->getNumElements(); 2764 if (unsigned Padding = Size - EmittedSize) 2765 AP.OutStreamer->emitZeros(Padding); 2766 } 2767 2768 static void emitGlobalConstantStruct(const DataLayout &DL, 2769 const ConstantStruct *CS, AsmPrinter &AP, 2770 const Constant *BaseCV, uint64_t Offset) { 2771 // Print the fields in successive locations. Pad to align if needed! 2772 unsigned Size = DL.getTypeAllocSize(CS->getType()); 2773 const StructLayout *Layout = DL.getStructLayout(CS->getType()); 2774 uint64_t SizeSoFar = 0; 2775 for (unsigned i = 0, e = CS->getNumOperands(); i != e; ++i) { 2776 const Constant *Field = CS->getOperand(i); 2777 2778 // Print the actual field value. 2779 emitGlobalConstantImpl(DL, Field, AP, BaseCV, Offset + SizeSoFar); 2780 2781 // Check if padding is needed and insert one or more 0s. 2782 uint64_t FieldSize = DL.getTypeAllocSize(Field->getType()); 2783 uint64_t PadSize = ((i == e-1 ? Size : Layout->getElementOffset(i+1)) 2784 - Layout->getElementOffset(i)) - FieldSize; 2785 SizeSoFar += FieldSize + PadSize; 2786 2787 // Insert padding - this may include padding to increase the size of the 2788 // current field up to the ABI size (if the struct is not packed) as well 2789 // as padding to ensure that the next field starts at the right offset. 2790 AP.OutStreamer->emitZeros(PadSize); 2791 } 2792 assert(SizeSoFar == Layout->getSizeInBytes() && 2793 "Layout of constant struct may be incorrect!"); 2794 } 2795 2796 static void emitGlobalConstantFP(APFloat APF, Type *ET, AsmPrinter &AP) { 2797 assert(ET && "Unknown float type"); 2798 APInt API = APF.bitcastToAPInt(); 2799 2800 // First print a comment with what we think the original floating-point value 2801 // should have been. 2802 if (AP.isVerbose()) { 2803 SmallString<8> StrVal; 2804 APF.toString(StrVal); 2805 ET->print(AP.OutStreamer->GetCommentOS()); 2806 AP.OutStreamer->GetCommentOS() << ' ' << StrVal << '\n'; 2807 } 2808 2809 // Now iterate through the APInt chunks, emitting them in endian-correct 2810 // order, possibly with a smaller chunk at beginning/end (e.g. for x87 80-bit 2811 // floats). 2812 unsigned NumBytes = API.getBitWidth() / 8; 2813 unsigned TrailingBytes = NumBytes % sizeof(uint64_t); 2814 const uint64_t *p = API.getRawData(); 2815 2816 // PPC's long double has odd notions of endianness compared to how LLVM 2817 // handles it: p[0] goes first for *big* endian on PPC. 2818 if (AP.getDataLayout().isBigEndian() && !ET->isPPC_FP128Ty()) { 2819 int Chunk = API.getNumWords() - 1; 2820 2821 if (TrailingBytes) 2822 AP.OutStreamer->emitIntValueInHexWithPadding(p[Chunk--], TrailingBytes); 2823 2824 for (; Chunk >= 0; --Chunk) 2825 AP.OutStreamer->emitIntValueInHexWithPadding(p[Chunk], sizeof(uint64_t)); 2826 } else { 2827 unsigned Chunk; 2828 for (Chunk = 0; Chunk < NumBytes / sizeof(uint64_t); ++Chunk) 2829 AP.OutStreamer->emitIntValueInHexWithPadding(p[Chunk], sizeof(uint64_t)); 2830 2831 if (TrailingBytes) 2832 AP.OutStreamer->emitIntValueInHexWithPadding(p[Chunk], TrailingBytes); 2833 } 2834 2835 // Emit the tail padding for the long double. 2836 const DataLayout &DL = AP.getDataLayout(); 2837 AP.OutStreamer->emitZeros(DL.getTypeAllocSize(ET) - DL.getTypeStoreSize(ET)); 2838 } 2839 2840 static void emitGlobalConstantFP(const ConstantFP *CFP, AsmPrinter &AP) { 2841 emitGlobalConstantFP(CFP->getValueAPF(), CFP->getType(), AP); 2842 } 2843 2844 static void emitGlobalConstantLargeInt(const ConstantInt *CI, AsmPrinter &AP) { 2845 const DataLayout &DL = AP.getDataLayout(); 2846 unsigned BitWidth = CI->getBitWidth(); 2847 2848 // Copy the value as we may massage the layout for constants whose bit width 2849 // is not a multiple of 64-bits. 2850 APInt Realigned(CI->getValue()); 2851 uint64_t ExtraBits = 0; 2852 unsigned ExtraBitsSize = BitWidth & 63; 2853 2854 if (ExtraBitsSize) { 2855 // The bit width of the data is not a multiple of 64-bits. 2856 // The extra bits are expected to be at the end of the chunk of the memory. 2857 // Little endian: 2858 // * Nothing to be done, just record the extra bits to emit. 2859 // Big endian: 2860 // * Record the extra bits to emit. 2861 // * Realign the raw data to emit the chunks of 64-bits. 2862 if (DL.isBigEndian()) { 2863 // Basically the structure of the raw data is a chunk of 64-bits cells: 2864 // 0 1 BitWidth / 64 2865 // [chunk1][chunk2] ... [chunkN]. 2866 // The most significant chunk is chunkN and it should be emitted first. 2867 // However, due to the alignment issue chunkN contains useless bits. 2868 // Realign the chunks so that they contain only useful information: 2869 // ExtraBits 0 1 (BitWidth / 64) - 1 2870 // chu[nk1 chu][nk2 chu] ... [nkN-1 chunkN] 2871 ExtraBitsSize = alignTo(ExtraBitsSize, 8); 2872 ExtraBits = Realigned.getRawData()[0] & 2873 (((uint64_t)-1) >> (64 - ExtraBitsSize)); 2874 Realigned.lshrInPlace(ExtraBitsSize); 2875 } else 2876 ExtraBits = Realigned.getRawData()[BitWidth / 64]; 2877 } 2878 2879 // We don't expect assemblers to support integer data directives 2880 // for more than 64 bits, so we emit the data in at most 64-bit 2881 // quantities at a time. 2882 const uint64_t *RawData = Realigned.getRawData(); 2883 for (unsigned i = 0, e = BitWidth / 64; i != e; ++i) { 2884 uint64_t Val = DL.isBigEndian() ? RawData[e - i - 1] : RawData[i]; 2885 AP.OutStreamer->emitIntValue(Val, 8); 2886 } 2887 2888 if (ExtraBitsSize) { 2889 // Emit the extra bits after the 64-bits chunks. 2890 2891 // Emit a directive that fills the expected size. 2892 uint64_t Size = AP.getDataLayout().getTypeStoreSize(CI->getType()); 2893 Size -= (BitWidth / 64) * 8; 2894 assert(Size && Size * 8 >= ExtraBitsSize && 2895 (ExtraBits & (((uint64_t)-1) >> (64 - ExtraBitsSize))) 2896 == ExtraBits && "Directive too small for extra bits."); 2897 AP.OutStreamer->emitIntValue(ExtraBits, Size); 2898 } 2899 } 2900 2901 /// Transform a not absolute MCExpr containing a reference to a GOT 2902 /// equivalent global, by a target specific GOT pc relative access to the 2903 /// final symbol. 2904 static void handleIndirectSymViaGOTPCRel(AsmPrinter &AP, const MCExpr **ME, 2905 const Constant *BaseCst, 2906 uint64_t Offset) { 2907 // The global @foo below illustrates a global that uses a got equivalent. 2908 // 2909 // @bar = global i32 42 2910 // @gotequiv = private unnamed_addr constant i32* @bar 2911 // @foo = i32 trunc (i64 sub (i64 ptrtoint (i32** @gotequiv to i64), 2912 // i64 ptrtoint (i32* @foo to i64)) 2913 // to i32) 2914 // 2915 // The cstexpr in @foo is converted into the MCExpr `ME`, where we actually 2916 // check whether @foo is suitable to use a GOTPCREL. `ME` is usually in the 2917 // form: 2918 // 2919 // foo = cstexpr, where 2920 // cstexpr := <gotequiv> - "." + <cst> 2921 // cstexpr := <gotequiv> - (<foo> - <offset from @foo base>) + <cst> 2922 // 2923 // After canonicalization by evaluateAsRelocatable `ME` turns into: 2924 // 2925 // cstexpr := <gotequiv> - <foo> + gotpcrelcst, where 2926 // gotpcrelcst := <offset from @foo base> + <cst> 2927 MCValue MV; 2928 if (!(*ME)->evaluateAsRelocatable(MV, nullptr, nullptr) || MV.isAbsolute()) 2929 return; 2930 const MCSymbolRefExpr *SymA = MV.getSymA(); 2931 if (!SymA) 2932 return; 2933 2934 // Check that GOT equivalent symbol is cached. 2935 const MCSymbol *GOTEquivSym = &SymA->getSymbol(); 2936 if (!AP.GlobalGOTEquivs.count(GOTEquivSym)) 2937 return; 2938 2939 const GlobalValue *BaseGV = dyn_cast_or_null<GlobalValue>(BaseCst); 2940 if (!BaseGV) 2941 return; 2942 2943 // Check for a valid base symbol 2944 const MCSymbol *BaseSym = AP.getSymbol(BaseGV); 2945 const MCSymbolRefExpr *SymB = MV.getSymB(); 2946 2947 if (!SymB || BaseSym != &SymB->getSymbol()) 2948 return; 2949 2950 // Make sure to match: 2951 // 2952 // gotpcrelcst := <offset from @foo base> + <cst> 2953 // 2954 // If gotpcrelcst is positive it means that we can safely fold the pc rel 2955 // displacement into the GOTPCREL. We can also can have an extra offset <cst> 2956 // if the target knows how to encode it. 2957 int64_t GOTPCRelCst = Offset + MV.getConstant(); 2958 if (GOTPCRelCst < 0) 2959 return; 2960 if (!AP.getObjFileLowering().supportGOTPCRelWithOffset() && GOTPCRelCst != 0) 2961 return; 2962 2963 // Emit the GOT PC relative to replace the got equivalent global, i.e.: 2964 // 2965 // bar: 2966 // .long 42 2967 // gotequiv: 2968 // .quad bar 2969 // foo: 2970 // .long gotequiv - "." + <cst> 2971 // 2972 // is replaced by the target specific equivalent to: 2973 // 2974 // bar: 2975 // .long 42 2976 // foo: 2977 // .long bar@GOTPCREL+<gotpcrelcst> 2978 AsmPrinter::GOTEquivUsePair Result = AP.GlobalGOTEquivs[GOTEquivSym]; 2979 const GlobalVariable *GV = Result.first; 2980 int NumUses = (int)Result.second; 2981 const GlobalValue *FinalGV = dyn_cast<GlobalValue>(GV->getOperand(0)); 2982 const MCSymbol *FinalSym = AP.getSymbol(FinalGV); 2983 *ME = AP.getObjFileLowering().getIndirectSymViaGOTPCRel( 2984 FinalGV, FinalSym, MV, Offset, AP.MMI, *AP.OutStreamer); 2985 2986 // Update GOT equivalent usage information 2987 --NumUses; 2988 if (NumUses >= 0) 2989 AP.GlobalGOTEquivs[GOTEquivSym] = std::make_pair(GV, NumUses); 2990 } 2991 2992 static void emitGlobalConstantImpl(const DataLayout &DL, const Constant *CV, 2993 AsmPrinter &AP, const Constant *BaseCV, 2994 uint64_t Offset) { 2995 uint64_t Size = DL.getTypeAllocSize(CV->getType()); 2996 2997 // Globals with sub-elements such as combinations of arrays and structs 2998 // are handled recursively by emitGlobalConstantImpl. Keep track of the 2999 // constant symbol base and the current position with BaseCV and Offset. 3000 if (!BaseCV && CV->hasOneUse()) 3001 BaseCV = dyn_cast<Constant>(CV->user_back()); 3002 3003 if (isa<ConstantAggregateZero>(CV) || isa<UndefValue>(CV)) 3004 return AP.OutStreamer->emitZeros(Size); 3005 3006 if (const ConstantInt *CI = dyn_cast<ConstantInt>(CV)) { 3007 const uint64_t StoreSize = DL.getTypeStoreSize(CV->getType()); 3008 3009 if (StoreSize <= 8) { 3010 if (AP.isVerbose()) 3011 AP.OutStreamer->GetCommentOS() << format("0x%" PRIx64 "\n", 3012 CI->getZExtValue()); 3013 AP.OutStreamer->emitIntValue(CI->getZExtValue(), StoreSize); 3014 } else { 3015 emitGlobalConstantLargeInt(CI, AP); 3016 } 3017 3018 // Emit tail padding if needed 3019 if (Size != StoreSize) 3020 AP.OutStreamer->emitZeros(Size - StoreSize); 3021 3022 return; 3023 } 3024 3025 if (const ConstantFP *CFP = dyn_cast<ConstantFP>(CV)) 3026 return emitGlobalConstantFP(CFP, AP); 3027 3028 if (isa<ConstantPointerNull>(CV)) { 3029 AP.OutStreamer->emitIntValue(0, Size); 3030 return; 3031 } 3032 3033 if (const ConstantDataSequential *CDS = dyn_cast<ConstantDataSequential>(CV)) 3034 return emitGlobalConstantDataSequential(DL, CDS, AP); 3035 3036 if (const ConstantArray *CVA = dyn_cast<ConstantArray>(CV)) 3037 return emitGlobalConstantArray(DL, CVA, AP, BaseCV, Offset); 3038 3039 if (const ConstantStruct *CVS = dyn_cast<ConstantStruct>(CV)) 3040 return emitGlobalConstantStruct(DL, CVS, AP, BaseCV, Offset); 3041 3042 if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(CV)) { 3043 // Look through bitcasts, which might not be able to be MCExpr'ized (e.g. of 3044 // vectors). 3045 if (CE->getOpcode() == Instruction::BitCast) 3046 return emitGlobalConstantImpl(DL, CE->getOperand(0), AP); 3047 3048 if (Size > 8) { 3049 // If the constant expression's size is greater than 64-bits, then we have 3050 // to emit the value in chunks. Try to constant fold the value and emit it 3051 // that way. 3052 Constant *New = ConstantFoldConstant(CE, DL); 3053 if (New != CE) 3054 return emitGlobalConstantImpl(DL, New, AP); 3055 } 3056 } 3057 3058 if (const ConstantVector *V = dyn_cast<ConstantVector>(CV)) 3059 return emitGlobalConstantVector(DL, V, AP); 3060 3061 // Otherwise, it must be a ConstantExpr. Lower it to an MCExpr, then emit it 3062 // thread the streamer with EmitValue. 3063 const MCExpr *ME = AP.lowerConstant(CV); 3064 3065 // Since lowerConstant already folded and got rid of all IR pointer and 3066 // integer casts, detect GOT equivalent accesses by looking into the MCExpr 3067 // directly. 3068 if (AP.getObjFileLowering().supportIndirectSymViaGOTPCRel()) 3069 handleIndirectSymViaGOTPCRel(AP, &ME, BaseCV, Offset); 3070 3071 AP.OutStreamer->emitValue(ME, Size); 3072 } 3073 3074 /// EmitGlobalConstant - Print a general LLVM constant to the .s file. 3075 void AsmPrinter::emitGlobalConstant(const DataLayout &DL, const Constant *CV) { 3076 uint64_t Size = DL.getTypeAllocSize(CV->getType()); 3077 if (Size) 3078 emitGlobalConstantImpl(DL, CV, *this); 3079 else if (MAI->hasSubsectionsViaSymbols()) { 3080 // If the global has zero size, emit a single byte so that two labels don't 3081 // look like they are at the same location. 3082 OutStreamer->emitIntValue(0, 1); 3083 } 3084 } 3085 3086 void AsmPrinter::emitMachineConstantPoolValue(MachineConstantPoolValue *MCPV) { 3087 // Target doesn't support this yet! 3088 llvm_unreachable("Target does not support EmitMachineConstantPoolValue"); 3089 } 3090 3091 void AsmPrinter::printOffset(int64_t Offset, raw_ostream &OS) const { 3092 if (Offset > 0) 3093 OS << '+' << Offset; 3094 else if (Offset < 0) 3095 OS << Offset; 3096 } 3097 3098 void AsmPrinter::emitNops(unsigned N) { 3099 MCInst Nop = MF->getSubtarget().getInstrInfo()->getNop(); 3100 for (; N; --N) 3101 EmitToStreamer(*OutStreamer, Nop); 3102 } 3103 3104 //===----------------------------------------------------------------------===// 3105 // Symbol Lowering Routines. 3106 //===----------------------------------------------------------------------===// 3107 3108 MCSymbol *AsmPrinter::createTempSymbol(const Twine &Name) const { 3109 return OutContext.createTempSymbol(Name, true); 3110 } 3111 3112 MCSymbol *AsmPrinter::GetBlockAddressSymbol(const BlockAddress *BA) const { 3113 return MMI->getAddrLabelSymbol(BA->getBasicBlock()); 3114 } 3115 3116 MCSymbol *AsmPrinter::GetBlockAddressSymbol(const BasicBlock *BB) const { 3117 return MMI->getAddrLabelSymbol(BB); 3118 } 3119 3120 /// GetCPISymbol - Return the symbol for the specified constant pool entry. 3121 MCSymbol *AsmPrinter::GetCPISymbol(unsigned CPID) const { 3122 if (getSubtargetInfo().getTargetTriple().isWindowsMSVCEnvironment()) { 3123 const MachineConstantPoolEntry &CPE = 3124 MF->getConstantPool()->getConstants()[CPID]; 3125 if (!CPE.isMachineConstantPoolEntry()) { 3126 const DataLayout &DL = MF->getDataLayout(); 3127 SectionKind Kind = CPE.getSectionKind(&DL); 3128 const Constant *C = CPE.Val.ConstVal; 3129 Align Alignment = CPE.Alignment; 3130 if (const MCSectionCOFF *S = dyn_cast<MCSectionCOFF>( 3131 getObjFileLowering().getSectionForConstant(DL, Kind, C, 3132 Alignment))) { 3133 if (MCSymbol *Sym = S->getCOMDATSymbol()) { 3134 if (Sym->isUndefined()) 3135 OutStreamer->emitSymbolAttribute(Sym, MCSA_Global); 3136 return Sym; 3137 } 3138 } 3139 } 3140 } 3141 3142 const DataLayout &DL = getDataLayout(); 3143 return OutContext.getOrCreateSymbol(Twine(DL.getPrivateGlobalPrefix()) + 3144 "CPI" + Twine(getFunctionNumber()) + "_" + 3145 Twine(CPID)); 3146 } 3147 3148 /// GetJTISymbol - Return the symbol for the specified jump table entry. 3149 MCSymbol *AsmPrinter::GetJTISymbol(unsigned JTID, bool isLinkerPrivate) const { 3150 return MF->getJTISymbol(JTID, OutContext, isLinkerPrivate); 3151 } 3152 3153 /// GetJTSetSymbol - Return the symbol for the specified jump table .set 3154 /// FIXME: privatize to AsmPrinter. 3155 MCSymbol *AsmPrinter::GetJTSetSymbol(unsigned UID, unsigned MBBID) const { 3156 const DataLayout &DL = getDataLayout(); 3157 return OutContext.getOrCreateSymbol(Twine(DL.getPrivateGlobalPrefix()) + 3158 Twine(getFunctionNumber()) + "_" + 3159 Twine(UID) + "_set_" + Twine(MBBID)); 3160 } 3161 3162 MCSymbol *AsmPrinter::getSymbolWithGlobalValueBase(const GlobalValue *GV, 3163 StringRef Suffix) const { 3164 return getObjFileLowering().getSymbolWithGlobalValueBase(GV, Suffix, TM); 3165 } 3166 3167 /// Return the MCSymbol for the specified ExternalSymbol. 3168 MCSymbol *AsmPrinter::GetExternalSymbolSymbol(StringRef Sym) const { 3169 SmallString<60> NameStr; 3170 Mangler::getNameWithPrefix(NameStr, Sym, getDataLayout()); 3171 return OutContext.getOrCreateSymbol(NameStr); 3172 } 3173 3174 /// PrintParentLoopComment - Print comments about parent loops of this one. 3175 static void PrintParentLoopComment(raw_ostream &OS, const MachineLoop *Loop, 3176 unsigned FunctionNumber) { 3177 if (!Loop) return; 3178 PrintParentLoopComment(OS, Loop->getParentLoop(), FunctionNumber); 3179 OS.indent(Loop->getLoopDepth()*2) 3180 << "Parent Loop BB" << FunctionNumber << "_" 3181 << Loop->getHeader()->getNumber() 3182 << " Depth=" << Loop->getLoopDepth() << '\n'; 3183 } 3184 3185 /// PrintChildLoopComment - Print comments about child loops within 3186 /// the loop for this basic block, with nesting. 3187 static void PrintChildLoopComment(raw_ostream &OS, const MachineLoop *Loop, 3188 unsigned FunctionNumber) { 3189 // Add child loop information 3190 for (const MachineLoop *CL : *Loop) { 3191 OS.indent(CL->getLoopDepth()*2) 3192 << "Child Loop BB" << FunctionNumber << "_" 3193 << CL->getHeader()->getNumber() << " Depth " << CL->getLoopDepth() 3194 << '\n'; 3195 PrintChildLoopComment(OS, CL, FunctionNumber); 3196 } 3197 } 3198 3199 /// emitBasicBlockLoopComments - Pretty-print comments for basic blocks. 3200 static void emitBasicBlockLoopComments(const MachineBasicBlock &MBB, 3201 const MachineLoopInfo *LI, 3202 const AsmPrinter &AP) { 3203 // Add loop depth information 3204 const MachineLoop *Loop = LI->getLoopFor(&MBB); 3205 if (!Loop) return; 3206 3207 MachineBasicBlock *Header = Loop->getHeader(); 3208 assert(Header && "No header for loop"); 3209 3210 // If this block is not a loop header, just print out what is the loop header 3211 // and return. 3212 if (Header != &MBB) { 3213 AP.OutStreamer->AddComment(" in Loop: Header=BB" + 3214 Twine(AP.getFunctionNumber())+"_" + 3215 Twine(Loop->getHeader()->getNumber())+ 3216 " Depth="+Twine(Loop->getLoopDepth())); 3217 return; 3218 } 3219 3220 // Otherwise, it is a loop header. Print out information about child and 3221 // parent loops. 3222 raw_ostream &OS = AP.OutStreamer->GetCommentOS(); 3223 3224 PrintParentLoopComment(OS, Loop->getParentLoop(), AP.getFunctionNumber()); 3225 3226 OS << "=>"; 3227 OS.indent(Loop->getLoopDepth()*2-2); 3228 3229 OS << "This "; 3230 if (Loop->isInnermost()) 3231 OS << "Inner "; 3232 OS << "Loop Header: Depth=" + Twine(Loop->getLoopDepth()) << '\n'; 3233 3234 PrintChildLoopComment(OS, Loop, AP.getFunctionNumber()); 3235 } 3236 3237 /// emitBasicBlockStart - This method prints the label for the specified 3238 /// MachineBasicBlock, an alignment (if present) and a comment describing 3239 /// it if appropriate. 3240 void AsmPrinter::emitBasicBlockStart(const MachineBasicBlock &MBB) { 3241 // End the previous funclet and start a new one. 3242 if (MBB.isEHFuncletEntry()) { 3243 for (const HandlerInfo &HI : Handlers) { 3244 HI.Handler->endFunclet(); 3245 HI.Handler->beginFunclet(MBB); 3246 } 3247 } 3248 3249 // Emit an alignment directive for this block, if needed. 3250 const Align Alignment = MBB.getAlignment(); 3251 if (Alignment != Align(1)) 3252 emitAlignment(Alignment); 3253 3254 // Switch to a new section if this basic block must begin a section. The 3255 // entry block is always placed in the function section and is handled 3256 // separately. 3257 if (MBB.isBeginSection() && !MBB.isEntryBlock()) { 3258 OutStreamer->SwitchSection( 3259 getObjFileLowering().getSectionForMachineBasicBlock(MF->getFunction(), 3260 MBB, TM)); 3261 CurrentSectionBeginSym = MBB.getSymbol(); 3262 } 3263 3264 // If the block has its address taken, emit any labels that were used to 3265 // reference the block. It is possible that there is more than one label 3266 // here, because multiple LLVM BB's may have been RAUW'd to this block after 3267 // the references were generated. 3268 if (MBB.hasAddressTaken()) { 3269 const BasicBlock *BB = MBB.getBasicBlock(); 3270 if (isVerbose()) 3271 OutStreamer->AddComment("Block address taken"); 3272 3273 // MBBs can have their address taken as part of CodeGen without having 3274 // their corresponding BB's address taken in IR 3275 if (BB->hasAddressTaken()) 3276 for (MCSymbol *Sym : MMI->getAddrLabelSymbolToEmit(BB)) 3277 OutStreamer->emitLabel(Sym); 3278 } 3279 3280 // Print some verbose block comments. 3281 if (isVerbose()) { 3282 if (const BasicBlock *BB = MBB.getBasicBlock()) { 3283 if (BB->hasName()) { 3284 BB->printAsOperand(OutStreamer->GetCommentOS(), 3285 /*PrintType=*/false, BB->getModule()); 3286 OutStreamer->GetCommentOS() << '\n'; 3287 } 3288 } 3289 3290 assert(MLI != nullptr && "MachineLoopInfo should has been computed"); 3291 emitBasicBlockLoopComments(MBB, MLI, *this); 3292 } 3293 3294 // Print the main label for the block. 3295 if (shouldEmitLabelForBasicBlock(MBB)) { 3296 if (isVerbose() && MBB.hasLabelMustBeEmitted()) 3297 OutStreamer->AddComment("Label of block must be emitted"); 3298 OutStreamer->emitLabel(MBB.getSymbol()); 3299 } else { 3300 if (isVerbose()) { 3301 // NOTE: Want this comment at start of line, don't emit with AddComment. 3302 OutStreamer->emitRawComment(" %bb." + Twine(MBB.getNumber()) + ":", 3303 false); 3304 } 3305 } 3306 3307 if (MBB.isEHCatchretTarget() && 3308 MAI->getExceptionHandlingType() == ExceptionHandling::WinEH) { 3309 OutStreamer->emitLabel(MBB.getEHCatchretSymbol()); 3310 } 3311 3312 // With BB sections, each basic block must handle CFI information on its own 3313 // if it begins a section (Entry block is handled separately by 3314 // AsmPrinterHandler::beginFunction). 3315 if (MBB.isBeginSection() && !MBB.isEntryBlock()) 3316 for (const HandlerInfo &HI : Handlers) 3317 HI.Handler->beginBasicBlock(MBB); 3318 } 3319 3320 void AsmPrinter::emitBasicBlockEnd(const MachineBasicBlock &MBB) { 3321 // Check if CFI information needs to be updated for this MBB with basic block 3322 // sections. 3323 if (MBB.isEndSection()) 3324 for (const HandlerInfo &HI : Handlers) 3325 HI.Handler->endBasicBlock(MBB); 3326 } 3327 3328 void AsmPrinter::emitVisibility(MCSymbol *Sym, unsigned Visibility, 3329 bool IsDefinition) const { 3330 MCSymbolAttr Attr = MCSA_Invalid; 3331 3332 switch (Visibility) { 3333 default: break; 3334 case GlobalValue::HiddenVisibility: 3335 if (IsDefinition) 3336 Attr = MAI->getHiddenVisibilityAttr(); 3337 else 3338 Attr = MAI->getHiddenDeclarationVisibilityAttr(); 3339 break; 3340 case GlobalValue::ProtectedVisibility: 3341 Attr = MAI->getProtectedVisibilityAttr(); 3342 break; 3343 } 3344 3345 if (Attr != MCSA_Invalid) 3346 OutStreamer->emitSymbolAttribute(Sym, Attr); 3347 } 3348 3349 bool AsmPrinter::shouldEmitLabelForBasicBlock( 3350 const MachineBasicBlock &MBB) const { 3351 // With `-fbasic-block-sections=`, a label is needed for every non-entry block 3352 // in the labels mode (option `=labels`) and every section beginning in the 3353 // sections mode (`=all` and `=list=`). 3354 if ((MF->hasBBLabels() || MBB.isBeginSection()) && !MBB.isEntryBlock()) 3355 return true; 3356 // A label is needed for any block with at least one predecessor (when that 3357 // predecessor is not the fallthrough predecessor, or if it is an EH funclet 3358 // entry, or if a label is forced). 3359 return !MBB.pred_empty() && 3360 (!isBlockOnlyReachableByFallthrough(&MBB) || MBB.isEHFuncletEntry() || 3361 MBB.hasLabelMustBeEmitted()); 3362 } 3363 3364 /// isBlockOnlyReachableByFallthough - Return true if the basic block has 3365 /// exactly one predecessor and the control transfer mechanism between 3366 /// the predecessor and this block is a fall-through. 3367 bool AsmPrinter:: 3368 isBlockOnlyReachableByFallthrough(const MachineBasicBlock *MBB) const { 3369 // If this is a landing pad, it isn't a fall through. If it has no preds, 3370 // then nothing falls through to it. 3371 if (MBB->isEHPad() || MBB->pred_empty()) 3372 return false; 3373 3374 // If there isn't exactly one predecessor, it can't be a fall through. 3375 if (MBB->pred_size() > 1) 3376 return false; 3377 3378 // The predecessor has to be immediately before this block. 3379 MachineBasicBlock *Pred = *MBB->pred_begin(); 3380 if (!Pred->isLayoutSuccessor(MBB)) 3381 return false; 3382 3383 // If the block is completely empty, then it definitely does fall through. 3384 if (Pred->empty()) 3385 return true; 3386 3387 // Check the terminators in the previous blocks 3388 for (const auto &MI : Pred->terminators()) { 3389 // If it is not a simple branch, we are in a table somewhere. 3390 if (!MI.isBranch() || MI.isIndirectBranch()) 3391 return false; 3392 3393 // If we are the operands of one of the branches, this is not a fall 3394 // through. Note that targets with delay slots will usually bundle 3395 // terminators with the delay slot instruction. 3396 for (ConstMIBundleOperands OP(MI); OP.isValid(); ++OP) { 3397 if (OP->isJTI()) 3398 return false; 3399 if (OP->isMBB() && OP->getMBB() == MBB) 3400 return false; 3401 } 3402 } 3403 3404 return true; 3405 } 3406 3407 GCMetadataPrinter *AsmPrinter::GetOrCreateGCPrinter(GCStrategy &S) { 3408 if (!S.usesMetadata()) 3409 return nullptr; 3410 3411 gcp_map_type &GCMap = getGCMap(GCMetadataPrinters); 3412 gcp_map_type::iterator GCPI = GCMap.find(&S); 3413 if (GCPI != GCMap.end()) 3414 return GCPI->second.get(); 3415 3416 auto Name = S.getName(); 3417 3418 for (const GCMetadataPrinterRegistry::entry &GCMetaPrinter : 3419 GCMetadataPrinterRegistry::entries()) 3420 if (Name == GCMetaPrinter.getName()) { 3421 std::unique_ptr<GCMetadataPrinter> GMP = GCMetaPrinter.instantiate(); 3422 GMP->S = &S; 3423 auto IterBool = GCMap.insert(std::make_pair(&S, std::move(GMP))); 3424 return IterBool.first->second.get(); 3425 } 3426 3427 report_fatal_error("no GCMetadataPrinter registered for GC: " + Twine(Name)); 3428 } 3429 3430 void AsmPrinter::emitStackMaps(StackMaps &SM) { 3431 GCModuleInfo *MI = getAnalysisIfAvailable<GCModuleInfo>(); 3432 assert(MI && "AsmPrinter didn't require GCModuleInfo?"); 3433 bool NeedsDefault = false; 3434 if (MI->begin() == MI->end()) 3435 // No GC strategy, use the default format. 3436 NeedsDefault = true; 3437 else 3438 for (auto &I : *MI) { 3439 if (GCMetadataPrinter *MP = GetOrCreateGCPrinter(*I)) 3440 if (MP->emitStackMaps(SM, *this)) 3441 continue; 3442 // The strategy doesn't have printer or doesn't emit custom stack maps. 3443 // Use the default format. 3444 NeedsDefault = true; 3445 } 3446 3447 if (NeedsDefault) 3448 SM.serializeToStackMapSection(); 3449 } 3450 3451 /// Pin vtable to this file. 3452 AsmPrinterHandler::~AsmPrinterHandler() = default; 3453 3454 void AsmPrinterHandler::markFunctionEnd() {} 3455 3456 // In the binary's "xray_instr_map" section, an array of these function entries 3457 // describes each instrumentation point. When XRay patches your code, the index 3458 // into this table will be given to your handler as a patch point identifier. 3459 void AsmPrinter::XRayFunctionEntry::emit(int Bytes, MCStreamer *Out) const { 3460 auto Kind8 = static_cast<uint8_t>(Kind); 3461 Out->emitBinaryData(StringRef(reinterpret_cast<const char *>(&Kind8), 1)); 3462 Out->emitBinaryData( 3463 StringRef(reinterpret_cast<const char *>(&AlwaysInstrument), 1)); 3464 Out->emitBinaryData(StringRef(reinterpret_cast<const char *>(&Version), 1)); 3465 auto Padding = (4 * Bytes) - ((2 * Bytes) + 3); 3466 assert(Padding >= 0 && "Instrumentation map entry > 4 * Word Size"); 3467 Out->emitZeros(Padding); 3468 } 3469 3470 void AsmPrinter::emitXRayTable() { 3471 if (Sleds.empty()) 3472 return; 3473 3474 auto PrevSection = OutStreamer->getCurrentSectionOnly(); 3475 const Function &F = MF->getFunction(); 3476 MCSection *InstMap = nullptr; 3477 MCSection *FnSledIndex = nullptr; 3478 const Triple &TT = TM.getTargetTriple(); 3479 // Use PC-relative addresses on all targets. 3480 if (TT.isOSBinFormatELF()) { 3481 auto LinkedToSym = cast<MCSymbolELF>(CurrentFnSym); 3482 auto Flags = ELF::SHF_ALLOC | ELF::SHF_LINK_ORDER; 3483 StringRef GroupName; 3484 if (F.hasComdat()) { 3485 Flags |= ELF::SHF_GROUP; 3486 GroupName = F.getComdat()->getName(); 3487 } 3488 InstMap = OutContext.getELFSection("xray_instr_map", ELF::SHT_PROGBITS, 3489 Flags, 0, GroupName, F.hasComdat(), 3490 MCSection::NonUniqueID, LinkedToSym); 3491 3492 if (!TM.Options.XRayOmitFunctionIndex) 3493 FnSledIndex = OutContext.getELFSection( 3494 "xray_fn_idx", ELF::SHT_PROGBITS, Flags | ELF::SHF_WRITE, 0, 3495 GroupName, F.hasComdat(), MCSection::NonUniqueID, LinkedToSym); 3496 } else if (MF->getSubtarget().getTargetTriple().isOSBinFormatMachO()) { 3497 InstMap = OutContext.getMachOSection("__DATA", "xray_instr_map", 0, 3498 SectionKind::getReadOnlyWithRel()); 3499 if (!TM.Options.XRayOmitFunctionIndex) 3500 FnSledIndex = OutContext.getMachOSection( 3501 "__DATA", "xray_fn_idx", 0, SectionKind::getReadOnlyWithRel()); 3502 } else { 3503 llvm_unreachable("Unsupported target"); 3504 } 3505 3506 auto WordSizeBytes = MAI->getCodePointerSize(); 3507 3508 // Now we switch to the instrumentation map section. Because this is done 3509 // per-function, we are able to create an index entry that will represent the 3510 // range of sleds associated with a function. 3511 auto &Ctx = OutContext; 3512 MCSymbol *SledsStart = OutContext.createTempSymbol("xray_sleds_start", true); 3513 OutStreamer->SwitchSection(InstMap); 3514 OutStreamer->emitLabel(SledsStart); 3515 for (const auto &Sled : Sleds) { 3516 MCSymbol *Dot = Ctx.createTempSymbol(); 3517 OutStreamer->emitLabel(Dot); 3518 OutStreamer->emitValueImpl( 3519 MCBinaryExpr::createSub(MCSymbolRefExpr::create(Sled.Sled, Ctx), 3520 MCSymbolRefExpr::create(Dot, Ctx), Ctx), 3521 WordSizeBytes); 3522 OutStreamer->emitValueImpl( 3523 MCBinaryExpr::createSub( 3524 MCSymbolRefExpr::create(CurrentFnBegin, Ctx), 3525 MCBinaryExpr::createAdd(MCSymbolRefExpr::create(Dot, Ctx), 3526 MCConstantExpr::create(WordSizeBytes, Ctx), 3527 Ctx), 3528 Ctx), 3529 WordSizeBytes); 3530 Sled.emit(WordSizeBytes, OutStreamer.get()); 3531 } 3532 MCSymbol *SledsEnd = OutContext.createTempSymbol("xray_sleds_end", true); 3533 OutStreamer->emitLabel(SledsEnd); 3534 3535 // We then emit a single entry in the index per function. We use the symbols 3536 // that bound the instrumentation map as the range for a specific function. 3537 // Each entry here will be 2 * word size aligned, as we're writing down two 3538 // pointers. This should work for both 32-bit and 64-bit platforms. 3539 if (FnSledIndex) { 3540 OutStreamer->SwitchSection(FnSledIndex); 3541 OutStreamer->emitCodeAlignment(2 * WordSizeBytes); 3542 OutStreamer->emitSymbolValue(SledsStart, WordSizeBytes, false); 3543 OutStreamer->emitSymbolValue(SledsEnd, WordSizeBytes, false); 3544 OutStreamer->SwitchSection(PrevSection); 3545 } 3546 Sleds.clear(); 3547 } 3548 3549 void AsmPrinter::recordSled(MCSymbol *Sled, const MachineInstr &MI, 3550 SledKind Kind, uint8_t Version) { 3551 const Function &F = MI.getMF()->getFunction(); 3552 auto Attr = F.getFnAttribute("function-instrument"); 3553 bool LogArgs = F.hasFnAttribute("xray-log-args"); 3554 bool AlwaysInstrument = 3555 Attr.isStringAttribute() && Attr.getValueAsString() == "xray-always"; 3556 if (Kind == SledKind::FUNCTION_ENTER && LogArgs) 3557 Kind = SledKind::LOG_ARGS_ENTER; 3558 Sleds.emplace_back(XRayFunctionEntry{Sled, CurrentFnSym, Kind, 3559 AlwaysInstrument, &F, Version}); 3560 } 3561 3562 void AsmPrinter::emitPatchableFunctionEntries() { 3563 const Function &F = MF->getFunction(); 3564 unsigned PatchableFunctionPrefix = 0, PatchableFunctionEntry = 0; 3565 (void)F.getFnAttribute("patchable-function-prefix") 3566 .getValueAsString() 3567 .getAsInteger(10, PatchableFunctionPrefix); 3568 (void)F.getFnAttribute("patchable-function-entry") 3569 .getValueAsString() 3570 .getAsInteger(10, PatchableFunctionEntry); 3571 if (!PatchableFunctionPrefix && !PatchableFunctionEntry) 3572 return; 3573 const unsigned PointerSize = getPointerSize(); 3574 if (TM.getTargetTriple().isOSBinFormatELF()) { 3575 auto Flags = ELF::SHF_WRITE | ELF::SHF_ALLOC; 3576 const MCSymbolELF *LinkedToSym = nullptr; 3577 StringRef GroupName; 3578 3579 // GNU as < 2.35 did not support section flag 'o'. GNU ld < 2.36 did not 3580 // support mixed SHF_LINK_ORDER and non-SHF_LINK_ORDER sections. 3581 if (MAI->useIntegratedAssembler() || MAI->binutilsIsAtLeast(2, 36)) { 3582 Flags |= ELF::SHF_LINK_ORDER; 3583 if (F.hasComdat()) { 3584 Flags |= ELF::SHF_GROUP; 3585 GroupName = F.getComdat()->getName(); 3586 } 3587 LinkedToSym = cast<MCSymbolELF>(CurrentFnSym); 3588 } 3589 OutStreamer->SwitchSection(OutContext.getELFSection( 3590 "__patchable_function_entries", ELF::SHT_PROGBITS, Flags, 0, GroupName, 3591 F.hasComdat(), MCSection::NonUniqueID, LinkedToSym)); 3592 emitAlignment(Align(PointerSize)); 3593 OutStreamer->emitSymbolValue(CurrentPatchableFunctionEntrySym, PointerSize); 3594 } 3595 } 3596 3597 uint16_t AsmPrinter::getDwarfVersion() const { 3598 return OutStreamer->getContext().getDwarfVersion(); 3599 } 3600 3601 void AsmPrinter::setDwarfVersion(uint16_t Version) { 3602 OutStreamer->getContext().setDwarfVersion(Version); 3603 } 3604 3605 bool AsmPrinter::isDwarf64() const { 3606 return OutStreamer->getContext().getDwarfFormat() == dwarf::DWARF64; 3607 } 3608 3609 unsigned int AsmPrinter::getDwarfOffsetByteSize() const { 3610 return dwarf::getDwarfOffsetByteSize( 3611 OutStreamer->getContext().getDwarfFormat()); 3612 } 3613 3614 unsigned int AsmPrinter::getUnitLengthFieldByteSize() const { 3615 return dwarf::getUnitLengthFieldByteSize( 3616 OutStreamer->getContext().getDwarfFormat()); 3617 } 3618