1 //===-- AsmPrinter.cpp - Common AsmPrinter code ---------------------------===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is distributed under the University of Illinois Open Source 6 // License. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 // 10 // This file implements the AsmPrinter class. 11 // 12 //===----------------------------------------------------------------------===// 13 14 #include "llvm/CodeGen/AsmPrinter.h" 15 #include "DwarfDebug.h" 16 #include "DwarfException.h" 17 #include "Win64Exception.h" 18 #include "WinCodeViewLineTables.h" 19 #include "llvm/ADT/SmallString.h" 20 #include "llvm/ADT/Statistic.h" 21 #include "llvm/Analysis/ConstantFolding.h" 22 #include "llvm/Analysis/JumpInstrTableInfo.h" 23 #include "llvm/CodeGen/Analysis.h" 24 #include "llvm/CodeGen/GCMetadataPrinter.h" 25 #include "llvm/CodeGen/MachineConstantPool.h" 26 #include "llvm/CodeGen/MachineFrameInfo.h" 27 #include "llvm/CodeGen/MachineFunction.h" 28 #include "llvm/CodeGen/MachineInstrBundle.h" 29 #include "llvm/CodeGen/MachineJumpTableInfo.h" 30 #include "llvm/CodeGen/MachineLoopInfo.h" 31 #include "llvm/CodeGen/MachineModuleInfoImpls.h" 32 #include "llvm/IR/DataLayout.h" 33 #include "llvm/IR/DebugInfo.h" 34 #include "llvm/IR/Mangler.h" 35 #include "llvm/IR/Module.h" 36 #include "llvm/IR/Operator.h" 37 #include "llvm/MC/MCAsmInfo.h" 38 #include "llvm/MC/MCContext.h" 39 #include "llvm/MC/MCExpr.h" 40 #include "llvm/MC/MCInst.h" 41 #include "llvm/MC/MCSection.h" 42 #include "llvm/MC/MCStreamer.h" 43 #include "llvm/MC/MCSymbol.h" 44 #include "llvm/MC/MCValue.h" 45 #include "llvm/Support/ErrorHandling.h" 46 #include "llvm/Support/Format.h" 47 #include "llvm/Support/MathExtras.h" 48 #include "llvm/Support/TargetRegistry.h" 49 #include "llvm/Support/Timer.h" 50 #include "llvm/Target/TargetFrameLowering.h" 51 #include "llvm/Target/TargetInstrInfo.h" 52 #include "llvm/Target/TargetLowering.h" 53 #include "llvm/Target/TargetLoweringObjectFile.h" 54 #include "llvm/Target/TargetRegisterInfo.h" 55 #include "llvm/Target/TargetSubtargetInfo.h" 56 using namespace llvm; 57 58 #define DEBUG_TYPE "asm-printer" 59 60 static const char *const DWARFGroupName = "DWARF Emission"; 61 static const char *const DbgTimerName = "Debug Info Emission"; 62 static const char *const EHTimerName = "DWARF Exception Writer"; 63 static const char *const CodeViewLineTablesGroupName = "CodeView Line Tables"; 64 65 STATISTIC(EmittedInsts, "Number of machine instrs printed"); 66 67 char AsmPrinter::ID = 0; 68 69 typedef DenseMap<GCStrategy*, std::unique_ptr<GCMetadataPrinter>> gcp_map_type; 70 static gcp_map_type &getGCMap(void *&P) { 71 if (!P) 72 P = new gcp_map_type(); 73 return *(gcp_map_type*)P; 74 } 75 76 77 /// getGVAlignmentLog2 - Return the alignment to use for the specified global 78 /// value in log2 form. This rounds up to the preferred alignment if possible 79 /// and legal. 80 static unsigned getGVAlignmentLog2(const GlobalValue *GV, const DataLayout &DL, 81 unsigned InBits = 0) { 82 unsigned NumBits = 0; 83 if (const GlobalVariable *GVar = dyn_cast<GlobalVariable>(GV)) 84 NumBits = DL.getPreferredAlignmentLog(GVar); 85 86 // If InBits is specified, round it to it. 87 if (InBits > NumBits) 88 NumBits = InBits; 89 90 // If the GV has a specified alignment, take it into account. 91 if (GV->getAlignment() == 0) 92 return NumBits; 93 94 unsigned GVAlign = Log2_32(GV->getAlignment()); 95 96 // If the GVAlign is larger than NumBits, or if we are required to obey 97 // NumBits because the GV has an assigned section, obey it. 98 if (GVAlign > NumBits || GV->hasSection()) 99 NumBits = GVAlign; 100 return NumBits; 101 } 102 103 AsmPrinter::AsmPrinter(TargetMachine &tm, std::unique_ptr<MCStreamer> Streamer) 104 : MachineFunctionPass(ID), TM(tm), MAI(tm.getMCAsmInfo()), 105 OutContext(Streamer->getContext()), OutStreamer(*Streamer.release()), 106 LastMI(nullptr), LastFn(0), Counter(~0U) { 107 DD = nullptr; 108 MMI = nullptr; 109 LI = nullptr; 110 MF = nullptr; 111 CurExceptionSym = CurrentFnSym = CurrentFnSymForSize = nullptr; 112 CurrentFnBegin = nullptr; 113 CurrentFnEnd = nullptr; 114 GCMetadataPrinters = nullptr; 115 VerboseAsm = OutStreamer.isVerboseAsm(); 116 } 117 118 AsmPrinter::~AsmPrinter() { 119 assert(!DD && Handlers.empty() && "Debug/EH info didn't get finalized"); 120 121 if (GCMetadataPrinters) { 122 gcp_map_type &GCMap = getGCMap(GCMetadataPrinters); 123 124 delete &GCMap; 125 GCMetadataPrinters = nullptr; 126 } 127 128 delete &OutStreamer; 129 } 130 131 /// getFunctionNumber - Return a unique ID for the current function. 132 /// 133 unsigned AsmPrinter::getFunctionNumber() const { 134 return MF->getFunctionNumber(); 135 } 136 137 const TargetLoweringObjectFile &AsmPrinter::getObjFileLowering() const { 138 return *TM.getObjFileLowering(); 139 } 140 141 /// getDataLayout - Return information about data layout. 142 const DataLayout &AsmPrinter::getDataLayout() const { 143 return *TM.getDataLayout(); 144 } 145 146 const MCSubtargetInfo &AsmPrinter::getSubtargetInfo() const { 147 assert(MF && "getSubtargetInfo requires a valid MachineFunction!"); 148 return MF->getSubtarget<MCSubtargetInfo>(); 149 } 150 151 void AsmPrinter::EmitToStreamer(MCStreamer &S, const MCInst &Inst) { 152 S.EmitInstruction(Inst, getSubtargetInfo()); 153 } 154 155 StringRef AsmPrinter::getTargetTriple() const { 156 return TM.getTargetTriple(); 157 } 158 159 /// getCurrentSection() - Return the current section we are emitting to. 160 const MCSection *AsmPrinter::getCurrentSection() const { 161 return OutStreamer.getCurrentSection().first; 162 } 163 164 165 166 void AsmPrinter::getAnalysisUsage(AnalysisUsage &AU) const { 167 AU.setPreservesAll(); 168 MachineFunctionPass::getAnalysisUsage(AU); 169 AU.addRequired<MachineModuleInfo>(); 170 AU.addRequired<GCModuleInfo>(); 171 if (isVerbose()) 172 AU.addRequired<MachineLoopInfo>(); 173 } 174 175 bool AsmPrinter::doInitialization(Module &M) { 176 MMI = getAnalysisIfAvailable<MachineModuleInfo>(); 177 MMI->AnalyzeModule(M); 178 179 // Initialize TargetLoweringObjectFile. 180 const_cast<TargetLoweringObjectFile&>(getObjFileLowering()) 181 .Initialize(OutContext, TM); 182 183 OutStreamer.InitSections(false); 184 185 Mang = new Mangler(TM.getDataLayout()); 186 187 // Emit the version-min deplyment target directive if needed. 188 // 189 // FIXME: If we end up with a collection of these sorts of Darwin-specific 190 // or ELF-specific things, it may make sense to have a platform helper class 191 // that will work with the target helper class. For now keep it here, as the 192 // alternative is duplicated code in each of the target asm printers that 193 // use the directive, where it would need the same conditionalization 194 // anyway. 195 Triple TT(getTargetTriple()); 196 if (TT.isOSDarwin()) { 197 unsigned Major, Minor, Update; 198 TT.getOSVersion(Major, Minor, Update); 199 // If there is a version specified, Major will be non-zero. 200 if (Major) 201 OutStreamer.EmitVersionMin((TT.isMacOSX() ? 202 MCVM_OSXVersionMin : MCVM_IOSVersionMin), 203 Major, Minor, Update); 204 } 205 206 // Allow the target to emit any magic that it wants at the start of the file. 207 EmitStartOfAsmFile(M); 208 209 // Very minimal debug info. It is ignored if we emit actual debug info. If we 210 // don't, this at least helps the user find where a global came from. 211 if (MAI->hasSingleParameterDotFile()) { 212 // .file "foo.c" 213 OutStreamer.EmitFileDirective(M.getModuleIdentifier()); 214 } 215 216 GCModuleInfo *MI = getAnalysisIfAvailable<GCModuleInfo>(); 217 assert(MI && "AsmPrinter didn't require GCModuleInfo?"); 218 for (auto &I : *MI) 219 if (GCMetadataPrinter *MP = GetOrCreateGCPrinter(*I)) 220 MP->beginAssembly(M, *MI, *this); 221 222 // Emit module-level inline asm if it exists. 223 if (!M.getModuleInlineAsm().empty()) { 224 // We're at the module level. Construct MCSubtarget from the default CPU 225 // and target triple. 226 std::unique_ptr<MCSubtargetInfo> STI(TM.getTarget().createMCSubtargetInfo( 227 TM.getTargetTriple(), TM.getTargetCPU(), TM.getTargetFeatureString())); 228 OutStreamer.AddComment("Start of file scope inline assembly"); 229 OutStreamer.AddBlankLine(); 230 EmitInlineAsm(M.getModuleInlineAsm()+"\n", *STI); 231 OutStreamer.AddComment("End of file scope inline assembly"); 232 OutStreamer.AddBlankLine(); 233 } 234 235 if (MAI->doesSupportDebugInformation()) { 236 bool skip_dwarf = false; 237 if (Triple(TM.getTargetTriple()).isKnownWindowsMSVCEnvironment()) { 238 Handlers.push_back(HandlerInfo(new WinCodeViewLineTables(this), 239 DbgTimerName, 240 CodeViewLineTablesGroupName)); 241 // FIXME: Don't emit DWARF debug info if there's at least one function 242 // with AddressSanitizer instrumentation. 243 // This is a band-aid fix for PR22032. 244 for (auto &F : M.functions()) { 245 if (F.hasFnAttribute(Attribute::SanitizeAddress)) { 246 skip_dwarf = true; 247 break; 248 } 249 } 250 } 251 if (!skip_dwarf) { 252 DD = new DwarfDebug(this, &M); 253 Handlers.push_back(HandlerInfo(DD, DbgTimerName, DWARFGroupName)); 254 } 255 } 256 257 EHStreamer *ES = nullptr; 258 switch (MAI->getExceptionHandlingType()) { 259 case ExceptionHandling::None: 260 break; 261 case ExceptionHandling::SjLj: 262 case ExceptionHandling::DwarfCFI: 263 ES = new DwarfCFIException(this); 264 break; 265 case ExceptionHandling::ARM: 266 ES = new ARMException(this); 267 break; 268 case ExceptionHandling::WinEH: 269 switch (MAI->getWinEHEncodingType()) { 270 default: llvm_unreachable("unsupported unwinding information encoding"); 271 case WinEH::EncodingType::Itanium: 272 ES = new Win64Exception(this); 273 break; 274 } 275 break; 276 } 277 if (ES) 278 Handlers.push_back(HandlerInfo(ES, EHTimerName, DWARFGroupName)); 279 return false; 280 } 281 282 static bool canBeHidden(const GlobalValue *GV, const MCAsmInfo &MAI) { 283 if (!MAI.hasWeakDefCanBeHiddenDirective()) 284 return false; 285 286 return canBeOmittedFromSymbolTable(GV); 287 } 288 289 void AsmPrinter::EmitLinkage(const GlobalValue *GV, MCSymbol *GVSym) const { 290 GlobalValue::LinkageTypes Linkage = GV->getLinkage(); 291 switch (Linkage) { 292 case GlobalValue::CommonLinkage: 293 case GlobalValue::LinkOnceAnyLinkage: 294 case GlobalValue::LinkOnceODRLinkage: 295 case GlobalValue::WeakAnyLinkage: 296 case GlobalValue::WeakODRLinkage: 297 if (MAI->hasWeakDefDirective()) { 298 // .globl _foo 299 OutStreamer.EmitSymbolAttribute(GVSym, MCSA_Global); 300 301 if (!canBeHidden(GV, *MAI)) 302 // .weak_definition _foo 303 OutStreamer.EmitSymbolAttribute(GVSym, MCSA_WeakDefinition); 304 else 305 OutStreamer.EmitSymbolAttribute(GVSym, MCSA_WeakDefAutoPrivate); 306 } else if (MAI->hasLinkOnceDirective()) { 307 // .globl _foo 308 OutStreamer.EmitSymbolAttribute(GVSym, MCSA_Global); 309 //NOTE: linkonce is handled by the section the symbol was assigned to. 310 } else { 311 // .weak _foo 312 OutStreamer.EmitSymbolAttribute(GVSym, MCSA_Weak); 313 } 314 return; 315 case GlobalValue::AppendingLinkage: 316 // FIXME: appending linkage variables should go into a section of 317 // their name or something. For now, just emit them as external. 318 case GlobalValue::ExternalLinkage: 319 // If external or appending, declare as a global symbol. 320 // .globl _foo 321 OutStreamer.EmitSymbolAttribute(GVSym, MCSA_Global); 322 return; 323 case GlobalValue::PrivateLinkage: 324 case GlobalValue::InternalLinkage: 325 return; 326 case GlobalValue::AvailableExternallyLinkage: 327 llvm_unreachable("Should never emit this"); 328 case GlobalValue::ExternalWeakLinkage: 329 llvm_unreachable("Don't know how to emit these"); 330 } 331 llvm_unreachable("Unknown linkage type!"); 332 } 333 334 void AsmPrinter::getNameWithPrefix(SmallVectorImpl<char> &Name, 335 const GlobalValue *GV) const { 336 TM.getNameWithPrefix(Name, GV, *Mang); 337 } 338 339 MCSymbol *AsmPrinter::getSymbol(const GlobalValue *GV) const { 340 return TM.getSymbol(GV, *Mang); 341 } 342 343 /// EmitGlobalVariable - Emit the specified global variable to the .s file. 344 void AsmPrinter::EmitGlobalVariable(const GlobalVariable *GV) { 345 if (GV->hasInitializer()) { 346 // Check to see if this is a special global used by LLVM, if so, emit it. 347 if (EmitSpecialLLVMGlobal(GV)) 348 return; 349 350 // Skip the emission of global equivalents. The symbol can be emitted later 351 // on by emitGlobalGOTEquivs in case it turns out to be needed. 352 if (GlobalGOTEquivs.count(getSymbol(GV))) 353 return; 354 355 if (isVerbose()) { 356 GV->printAsOperand(OutStreamer.GetCommentOS(), 357 /*PrintType=*/false, GV->getParent()); 358 OutStreamer.GetCommentOS() << '\n'; 359 } 360 } 361 362 MCSymbol *GVSym = getSymbol(GV); 363 EmitVisibility(GVSym, GV->getVisibility(), !GV->isDeclaration()); 364 365 if (!GV->hasInitializer()) // External globals require no extra code. 366 return; 367 368 GVSym->redefineIfPossible(); 369 if (GVSym->isDefined() || GVSym->isVariable()) 370 report_fatal_error("symbol '" + Twine(GVSym->getName()) + 371 "' is already defined"); 372 373 if (MAI->hasDotTypeDotSizeDirective()) 374 OutStreamer.EmitSymbolAttribute(GVSym, MCSA_ELF_TypeObject); 375 376 SectionKind GVKind = TargetLoweringObjectFile::getKindForGlobal(GV, TM); 377 378 const DataLayout *DL = TM.getDataLayout(); 379 uint64_t Size = DL->getTypeAllocSize(GV->getType()->getElementType()); 380 381 // If the alignment is specified, we *must* obey it. Overaligning a global 382 // with a specified alignment is a prompt way to break globals emitted to 383 // sections and expected to be contiguous (e.g. ObjC metadata). 384 unsigned AlignLog = getGVAlignmentLog2(GV, *DL); 385 386 for (const HandlerInfo &HI : Handlers) { 387 NamedRegionTimer T(HI.TimerName, HI.TimerGroupName, TimePassesIsEnabled); 388 HI.Handler->setSymbolSize(GVSym, Size); 389 } 390 391 // Handle common and BSS local symbols (.lcomm). 392 if (GVKind.isCommon() || GVKind.isBSSLocal()) { 393 if (Size == 0) Size = 1; // .comm Foo, 0 is undefined, avoid it. 394 unsigned Align = 1 << AlignLog; 395 396 // Handle common symbols. 397 if (GVKind.isCommon()) { 398 if (!getObjFileLowering().getCommDirectiveSupportsAlignment()) 399 Align = 0; 400 401 // .comm _foo, 42, 4 402 OutStreamer.EmitCommonSymbol(GVSym, Size, Align); 403 return; 404 } 405 406 // Handle local BSS symbols. 407 if (MAI->hasMachoZeroFillDirective()) { 408 const MCSection *TheSection = 409 getObjFileLowering().SectionForGlobal(GV, GVKind, *Mang, TM); 410 // .zerofill __DATA, __bss, _foo, 400, 5 411 OutStreamer.EmitZerofill(TheSection, GVSym, Size, Align); 412 return; 413 } 414 415 // Use .lcomm only if it supports user-specified alignment. 416 // Otherwise, while it would still be correct to use .lcomm in some 417 // cases (e.g. when Align == 1), the external assembler might enfore 418 // some -unknown- default alignment behavior, which could cause 419 // spurious differences between external and integrated assembler. 420 // Prefer to simply fall back to .local / .comm in this case. 421 if (MAI->getLCOMMDirectiveAlignmentType() != LCOMM::NoAlignment) { 422 // .lcomm _foo, 42 423 OutStreamer.EmitLocalCommonSymbol(GVSym, Size, Align); 424 return; 425 } 426 427 if (!getObjFileLowering().getCommDirectiveSupportsAlignment()) 428 Align = 0; 429 430 // .local _foo 431 OutStreamer.EmitSymbolAttribute(GVSym, MCSA_Local); 432 // .comm _foo, 42, 4 433 OutStreamer.EmitCommonSymbol(GVSym, Size, Align); 434 return; 435 } 436 437 const MCSection *TheSection = 438 getObjFileLowering().SectionForGlobal(GV, GVKind, *Mang, TM); 439 440 // Handle the zerofill directive on darwin, which is a special form of BSS 441 // emission. 442 if (GVKind.isBSSExtern() && MAI->hasMachoZeroFillDirective()) { 443 if (Size == 0) Size = 1; // zerofill of 0 bytes is undefined. 444 445 // .globl _foo 446 OutStreamer.EmitSymbolAttribute(GVSym, MCSA_Global); 447 // .zerofill __DATA, __common, _foo, 400, 5 448 OutStreamer.EmitZerofill(TheSection, GVSym, Size, 1 << AlignLog); 449 return; 450 } 451 452 // Handle thread local data for mach-o which requires us to output an 453 // additional structure of data and mangle the original symbol so that we 454 // can reference it later. 455 // 456 // TODO: This should become an "emit thread local global" method on TLOF. 457 // All of this macho specific stuff should be sunk down into TLOFMachO and 458 // stuff like "TLSExtraDataSection" should no longer be part of the parent 459 // TLOF class. This will also make it more obvious that stuff like 460 // MCStreamer::EmitTBSSSymbol is macho specific and only called from macho 461 // specific code. 462 if (GVKind.isThreadLocal() && MAI->hasMachoTBSSDirective()) { 463 // Emit the .tbss symbol 464 MCSymbol *MangSym = 465 OutContext.GetOrCreateSymbol(GVSym->getName() + Twine("$tlv$init")); 466 467 if (GVKind.isThreadBSS()) { 468 TheSection = getObjFileLowering().getTLSBSSSection(); 469 OutStreamer.EmitTBSSSymbol(TheSection, MangSym, Size, 1 << AlignLog); 470 } else if (GVKind.isThreadData()) { 471 OutStreamer.SwitchSection(TheSection); 472 473 EmitAlignment(AlignLog, GV); 474 OutStreamer.EmitLabel(MangSym); 475 476 EmitGlobalConstant(GV->getInitializer()); 477 } 478 479 OutStreamer.AddBlankLine(); 480 481 // Emit the variable struct for the runtime. 482 const MCSection *TLVSect 483 = getObjFileLowering().getTLSExtraDataSection(); 484 485 OutStreamer.SwitchSection(TLVSect); 486 // Emit the linkage here. 487 EmitLinkage(GV, GVSym); 488 OutStreamer.EmitLabel(GVSym); 489 490 // Three pointers in size: 491 // - __tlv_bootstrap - used to make sure support exists 492 // - spare pointer, used when mapped by the runtime 493 // - pointer to mangled symbol above with initializer 494 unsigned PtrSize = DL->getPointerTypeSize(GV->getType()); 495 OutStreamer.EmitSymbolValue(GetExternalSymbolSymbol("_tlv_bootstrap"), 496 PtrSize); 497 OutStreamer.EmitIntValue(0, PtrSize); 498 OutStreamer.EmitSymbolValue(MangSym, PtrSize); 499 500 OutStreamer.AddBlankLine(); 501 return; 502 } 503 504 OutStreamer.SwitchSection(TheSection); 505 506 EmitLinkage(GV, GVSym); 507 EmitAlignment(AlignLog, GV); 508 509 OutStreamer.EmitLabel(GVSym); 510 511 EmitGlobalConstant(GV->getInitializer()); 512 513 if (MAI->hasDotTypeDotSizeDirective()) 514 // .size foo, 42 515 OutStreamer.EmitELFSize(GVSym, MCConstantExpr::Create(Size, OutContext)); 516 517 OutStreamer.AddBlankLine(); 518 } 519 520 /// EmitFunctionHeader - This method emits the header for the current 521 /// function. 522 void AsmPrinter::EmitFunctionHeader() { 523 // Print out constants referenced by the function 524 EmitConstantPool(); 525 526 // Print the 'header' of function. 527 const Function *F = MF->getFunction(); 528 529 OutStreamer.SwitchSection( 530 getObjFileLowering().SectionForGlobal(F, *Mang, TM)); 531 EmitVisibility(CurrentFnSym, F->getVisibility()); 532 533 EmitLinkage(F, CurrentFnSym); 534 if (MAI->hasFunctionAlignment()) 535 EmitAlignment(MF->getAlignment(), F); 536 537 if (MAI->hasDotTypeDotSizeDirective()) 538 OutStreamer.EmitSymbolAttribute(CurrentFnSym, MCSA_ELF_TypeFunction); 539 540 if (isVerbose()) { 541 F->printAsOperand(OutStreamer.GetCommentOS(), 542 /*PrintType=*/false, F->getParent()); 543 OutStreamer.GetCommentOS() << '\n'; 544 } 545 546 // Emit the prefix data. 547 if (F->hasPrefixData()) 548 EmitGlobalConstant(F->getPrefixData()); 549 550 // Emit the CurrentFnSym. This is a virtual function to allow targets to 551 // do their wild and crazy things as required. 552 EmitFunctionEntryLabel(); 553 554 // If the function had address-taken blocks that got deleted, then we have 555 // references to the dangling symbols. Emit them at the start of the function 556 // so that we don't get references to undefined symbols. 557 std::vector<MCSymbol*> DeadBlockSyms; 558 MMI->takeDeletedSymbolsForFunction(F, DeadBlockSyms); 559 for (unsigned i = 0, e = DeadBlockSyms.size(); i != e; ++i) { 560 OutStreamer.AddComment("Address taken block that was later removed"); 561 OutStreamer.EmitLabel(DeadBlockSyms[i]); 562 } 563 564 if (CurrentFnBegin) { 565 if (MAI->useAssignmentForEHBegin()) { 566 MCSymbol *CurPos = OutContext.CreateTempSymbol(); 567 OutStreamer.EmitLabel(CurPos); 568 OutStreamer.EmitAssignment(CurrentFnBegin, 569 MCSymbolRefExpr::Create(CurPos, OutContext)); 570 } else { 571 OutStreamer.EmitLabel(CurrentFnBegin); 572 } 573 } 574 575 // Emit pre-function debug and/or EH information. 576 for (const HandlerInfo &HI : Handlers) { 577 NamedRegionTimer T(HI.TimerName, HI.TimerGroupName, TimePassesIsEnabled); 578 HI.Handler->beginFunction(MF); 579 } 580 581 // Emit the prologue data. 582 if (F->hasPrologueData()) 583 EmitGlobalConstant(F->getPrologueData()); 584 } 585 586 /// EmitFunctionEntryLabel - Emit the label that is the entrypoint for the 587 /// function. This can be overridden by targets as required to do custom stuff. 588 void AsmPrinter::EmitFunctionEntryLabel() { 589 CurrentFnSym->redefineIfPossible(); 590 591 // The function label could have already been emitted if two symbols end up 592 // conflicting due to asm renaming. Detect this and emit an error. 593 if (CurrentFnSym->isVariable()) 594 report_fatal_error("'" + Twine(CurrentFnSym->getName()) + 595 "' is a protected alias"); 596 if (CurrentFnSym->isDefined()) 597 report_fatal_error("'" + Twine(CurrentFnSym->getName()) + 598 "' label emitted multiple times to assembly file"); 599 600 return OutStreamer.EmitLabel(CurrentFnSym); 601 } 602 603 /// emitComments - Pretty-print comments for instructions. 604 static void emitComments(const MachineInstr &MI, raw_ostream &CommentOS) { 605 const MachineFunction *MF = MI.getParent()->getParent(); 606 const TargetInstrInfo *TII = MF->getSubtarget().getInstrInfo(); 607 608 // Check for spills and reloads 609 int FI; 610 611 const MachineFrameInfo *FrameInfo = MF->getFrameInfo(); 612 613 // We assume a single instruction only has a spill or reload, not 614 // both. 615 const MachineMemOperand *MMO; 616 if (TII->isLoadFromStackSlotPostFE(&MI, FI)) { 617 if (FrameInfo->isSpillSlotObjectIndex(FI)) { 618 MMO = *MI.memoperands_begin(); 619 CommentOS << MMO->getSize() << "-byte Reload\n"; 620 } 621 } else if (TII->hasLoadFromStackSlot(&MI, MMO, FI)) { 622 if (FrameInfo->isSpillSlotObjectIndex(FI)) 623 CommentOS << MMO->getSize() << "-byte Folded Reload\n"; 624 } else if (TII->isStoreToStackSlotPostFE(&MI, FI)) { 625 if (FrameInfo->isSpillSlotObjectIndex(FI)) { 626 MMO = *MI.memoperands_begin(); 627 CommentOS << MMO->getSize() << "-byte Spill\n"; 628 } 629 } else if (TII->hasStoreToStackSlot(&MI, MMO, FI)) { 630 if (FrameInfo->isSpillSlotObjectIndex(FI)) 631 CommentOS << MMO->getSize() << "-byte Folded Spill\n"; 632 } 633 634 // Check for spill-induced copies 635 if (MI.getAsmPrinterFlag(MachineInstr::ReloadReuse)) 636 CommentOS << " Reload Reuse\n"; 637 } 638 639 /// emitImplicitDef - This method emits the specified machine instruction 640 /// that is an implicit def. 641 void AsmPrinter::emitImplicitDef(const MachineInstr *MI) const { 642 unsigned RegNo = MI->getOperand(0).getReg(); 643 OutStreamer.AddComment(Twine("implicit-def: ") + 644 MMI->getContext().getRegisterInfo()->getName(RegNo)); 645 OutStreamer.AddBlankLine(); 646 } 647 648 static void emitKill(const MachineInstr *MI, AsmPrinter &AP) { 649 std::string Str = "kill:"; 650 for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) { 651 const MachineOperand &Op = MI->getOperand(i); 652 assert(Op.isReg() && "KILL instruction must have only register operands"); 653 Str += ' '; 654 Str += AP.MMI->getContext().getRegisterInfo()->getName(Op.getReg()); 655 Str += (Op.isDef() ? "<def>" : "<kill>"); 656 } 657 AP.OutStreamer.AddComment(Str); 658 AP.OutStreamer.AddBlankLine(); 659 } 660 661 /// emitDebugValueComment - This method handles the target-independent form 662 /// of DBG_VALUE, returning true if it was able to do so. A false return 663 /// means the target will need to handle MI in EmitInstruction. 664 static bool emitDebugValueComment(const MachineInstr *MI, AsmPrinter &AP) { 665 // This code handles only the 4-operand target-independent form. 666 if (MI->getNumOperands() != 4) 667 return false; 668 669 SmallString<128> Str; 670 raw_svector_ostream OS(Str); 671 OS << "DEBUG_VALUE: "; 672 673 DIVariable V = MI->getDebugVariable(); 674 if (auto *SP = dyn_cast<MDSubprogram>(V->getScope())) { 675 StringRef Name = SP->getDisplayName(); 676 if (!Name.empty()) 677 OS << Name << ":"; 678 } 679 OS << V->getName(); 680 681 DIExpression Expr = MI->getDebugExpression(); 682 if (Expr->isBitPiece()) 683 OS << " [bit_piece offset=" << Expr->getBitPieceOffset() 684 << " size=" << Expr->getBitPieceSize() << "]"; 685 OS << " <- "; 686 687 // The second operand is only an offset if it's an immediate. 688 bool Deref = MI->getOperand(0).isReg() && MI->getOperand(1).isImm(); 689 int64_t Offset = Deref ? MI->getOperand(1).getImm() : 0; 690 691 // Register or immediate value. Register 0 means undef. 692 if (MI->getOperand(0).isFPImm()) { 693 APFloat APF = APFloat(MI->getOperand(0).getFPImm()->getValueAPF()); 694 if (MI->getOperand(0).getFPImm()->getType()->isFloatTy()) { 695 OS << (double)APF.convertToFloat(); 696 } else if (MI->getOperand(0).getFPImm()->getType()->isDoubleTy()) { 697 OS << APF.convertToDouble(); 698 } else { 699 // There is no good way to print long double. Convert a copy to 700 // double. Ah well, it's only a comment. 701 bool ignored; 702 APF.convert(APFloat::IEEEdouble, APFloat::rmNearestTiesToEven, 703 &ignored); 704 OS << "(long double) " << APF.convertToDouble(); 705 } 706 } else if (MI->getOperand(0).isImm()) { 707 OS << MI->getOperand(0).getImm(); 708 } else if (MI->getOperand(0).isCImm()) { 709 MI->getOperand(0).getCImm()->getValue().print(OS, false /*isSigned*/); 710 } else { 711 unsigned Reg; 712 if (MI->getOperand(0).isReg()) { 713 Reg = MI->getOperand(0).getReg(); 714 } else { 715 assert(MI->getOperand(0).isFI() && "Unknown operand type"); 716 const TargetFrameLowering *TFI = AP.MF->getSubtarget().getFrameLowering(); 717 Offset += TFI->getFrameIndexReference(*AP.MF, 718 MI->getOperand(0).getIndex(), Reg); 719 Deref = true; 720 } 721 if (Reg == 0) { 722 // Suppress offset, it is not meaningful here. 723 OS << "undef"; 724 // NOTE: Want this comment at start of line, don't emit with AddComment. 725 AP.OutStreamer.emitRawComment(OS.str()); 726 return true; 727 } 728 if (Deref) 729 OS << '['; 730 OS << AP.MMI->getContext().getRegisterInfo()->getName(Reg); 731 } 732 733 if (Deref) 734 OS << '+' << Offset << ']'; 735 736 // NOTE: Want this comment at start of line, don't emit with AddComment. 737 AP.OutStreamer.emitRawComment(OS.str()); 738 return true; 739 } 740 741 AsmPrinter::CFIMoveType AsmPrinter::needsCFIMoves() { 742 if (MAI->getExceptionHandlingType() == ExceptionHandling::DwarfCFI && 743 MF->getFunction()->needsUnwindTableEntry()) 744 return CFI_M_EH; 745 746 if (MMI->hasDebugInfo()) 747 return CFI_M_Debug; 748 749 return CFI_M_None; 750 } 751 752 bool AsmPrinter::needsSEHMoves() { 753 return MAI->usesWindowsCFI() && MF->getFunction()->needsUnwindTableEntry(); 754 } 755 756 void AsmPrinter::emitCFIInstruction(const MachineInstr &MI) { 757 ExceptionHandling ExceptionHandlingType = MAI->getExceptionHandlingType(); 758 if (ExceptionHandlingType != ExceptionHandling::DwarfCFI && 759 ExceptionHandlingType != ExceptionHandling::ARM) 760 return; 761 762 if (needsCFIMoves() == CFI_M_None) 763 return; 764 765 const MachineModuleInfo &MMI = MF->getMMI(); 766 const std::vector<MCCFIInstruction> &Instrs = MMI.getFrameInstructions(); 767 unsigned CFIIndex = MI.getOperand(0).getCFIIndex(); 768 const MCCFIInstruction &CFI = Instrs[CFIIndex]; 769 emitCFIInstruction(CFI); 770 } 771 772 void AsmPrinter::emitFrameAlloc(const MachineInstr &MI) { 773 // The operands are the MCSymbol and the frame offset of the allocation. 774 MCSymbol *FrameAllocSym = MI.getOperand(0).getMCSymbol(); 775 int FrameOffset = MI.getOperand(1).getImm(); 776 777 // Emit a symbol assignment. 778 OutStreamer.EmitAssignment(FrameAllocSym, 779 MCConstantExpr::Create(FrameOffset, OutContext)); 780 } 781 782 /// EmitFunctionBody - This method emits the body and trailer for a 783 /// function. 784 void AsmPrinter::EmitFunctionBody() { 785 EmitFunctionHeader(); 786 787 // Emit target-specific gunk before the function body. 788 EmitFunctionBodyStart(); 789 790 bool ShouldPrintDebugScopes = MMI->hasDebugInfo(); 791 792 // Print out code for the function. 793 bool HasAnyRealCode = false; 794 for (auto &MBB : *MF) { 795 // Print a label for the basic block. 796 EmitBasicBlockStart(MBB); 797 for (auto &MI : MBB) { 798 799 // Print the assembly for the instruction. 800 if (!MI.isPosition() && !MI.isImplicitDef() && !MI.isKill() && 801 !MI.isDebugValue()) { 802 HasAnyRealCode = true; 803 ++EmittedInsts; 804 } 805 806 if (ShouldPrintDebugScopes) { 807 for (const HandlerInfo &HI : Handlers) { 808 NamedRegionTimer T(HI.TimerName, HI.TimerGroupName, 809 TimePassesIsEnabled); 810 HI.Handler->beginInstruction(&MI); 811 } 812 } 813 814 if (isVerbose()) 815 emitComments(MI, OutStreamer.GetCommentOS()); 816 817 switch (MI.getOpcode()) { 818 case TargetOpcode::CFI_INSTRUCTION: 819 emitCFIInstruction(MI); 820 break; 821 822 case TargetOpcode::FRAME_ALLOC: 823 emitFrameAlloc(MI); 824 break; 825 826 case TargetOpcode::EH_LABEL: 827 case TargetOpcode::GC_LABEL: 828 OutStreamer.EmitLabel(MI.getOperand(0).getMCSymbol()); 829 break; 830 case TargetOpcode::INLINEASM: 831 EmitInlineAsm(&MI); 832 break; 833 case TargetOpcode::DBG_VALUE: 834 if (isVerbose()) { 835 if (!emitDebugValueComment(&MI, *this)) 836 EmitInstruction(&MI); 837 } 838 break; 839 case TargetOpcode::IMPLICIT_DEF: 840 if (isVerbose()) emitImplicitDef(&MI); 841 break; 842 case TargetOpcode::KILL: 843 if (isVerbose()) emitKill(&MI, *this); 844 break; 845 default: 846 EmitInstruction(&MI); 847 break; 848 } 849 850 if (ShouldPrintDebugScopes) { 851 for (const HandlerInfo &HI : Handlers) { 852 NamedRegionTimer T(HI.TimerName, HI.TimerGroupName, 853 TimePassesIsEnabled); 854 HI.Handler->endInstruction(); 855 } 856 } 857 } 858 859 EmitBasicBlockEnd(MBB); 860 } 861 862 // If the function is empty and the object file uses .subsections_via_symbols, 863 // then we need to emit *something* to the function body to prevent the 864 // labels from collapsing together. Just emit a noop. 865 if ((MAI->hasSubsectionsViaSymbols() && !HasAnyRealCode)) { 866 MCInst Noop; 867 MF->getSubtarget().getInstrInfo()->getNoopForMachoTarget(Noop); 868 OutStreamer.AddComment("avoids zero-length function"); 869 870 // Targets can opt-out of emitting the noop here by leaving the opcode 871 // unspecified. 872 if (Noop.getOpcode()) 873 OutStreamer.EmitInstruction(Noop, getSubtargetInfo()); 874 } 875 876 const Function *F = MF->getFunction(); 877 for (const auto &BB : *F) { 878 if (!BB.hasAddressTaken()) 879 continue; 880 MCSymbol *Sym = GetBlockAddressSymbol(&BB); 881 if (Sym->isDefined()) 882 continue; 883 OutStreamer.AddComment("Address of block that was removed by CodeGen"); 884 OutStreamer.EmitLabel(Sym); 885 } 886 887 // Emit target-specific gunk after the function body. 888 EmitFunctionBodyEnd(); 889 890 if (!MMI->getLandingPads().empty() || MMI->hasDebugInfo() || 891 MAI->hasDotTypeDotSizeDirective()) { 892 // Create a symbol for the end of function. 893 CurrentFnEnd = createTempSymbol("func_end"); 894 OutStreamer.EmitLabel(CurrentFnEnd); 895 } 896 897 // If the target wants a .size directive for the size of the function, emit 898 // it. 899 if (MAI->hasDotTypeDotSizeDirective()) { 900 // We can get the size as difference between the function label and the 901 // temp label. 902 const MCExpr *SizeExp = 903 MCBinaryExpr::CreateSub(MCSymbolRefExpr::Create(CurrentFnEnd, OutContext), 904 MCSymbolRefExpr::Create(CurrentFnSymForSize, 905 OutContext), 906 OutContext); 907 OutStreamer.EmitELFSize(CurrentFnSym, SizeExp); 908 } 909 910 for (const HandlerInfo &HI : Handlers) { 911 NamedRegionTimer T(HI.TimerName, HI.TimerGroupName, TimePassesIsEnabled); 912 HI.Handler->markFunctionEnd(); 913 } 914 915 // Print out jump tables referenced by the function. 916 EmitJumpTableInfo(); 917 918 // Emit post-function debug and/or EH information. 919 for (const HandlerInfo &HI : Handlers) { 920 NamedRegionTimer T(HI.TimerName, HI.TimerGroupName, TimePassesIsEnabled); 921 HI.Handler->endFunction(MF); 922 } 923 MMI->EndFunction(); 924 925 OutStreamer.AddBlankLine(); 926 } 927 928 /// \brief Compute the number of Global Variables that uses a Constant. 929 static unsigned getNumGlobalVariableUses(const Constant *C) { 930 if (!C) 931 return 0; 932 933 if (isa<GlobalVariable>(C)) 934 return 1; 935 936 unsigned NumUses = 0; 937 for (auto *CU : C->users()) 938 NumUses += getNumGlobalVariableUses(dyn_cast<Constant>(CU)); 939 940 return NumUses; 941 } 942 943 /// \brief Only consider global GOT equivalents if at least one user is a 944 /// cstexpr inside an initializer of another global variables. Also, don't 945 /// handle cstexpr inside instructions. During global variable emission, 946 /// candidates are skipped and are emitted later in case at least one cstexpr 947 /// isn't replaced by a PC relative GOT entry access. 948 static bool isGOTEquivalentCandidate(const GlobalVariable *GV, 949 unsigned &NumGOTEquivUsers) { 950 // Global GOT equivalents are unnamed private globals with a constant 951 // pointer initializer to another global symbol. They must point to a 952 // GlobalVariable or Function, i.e., as GlobalValue. 953 if (!GV->hasUnnamedAddr() || !GV->hasInitializer() || !GV->isConstant() || 954 !GV->isDiscardableIfUnused() || !dyn_cast<GlobalValue>(GV->getOperand(0))) 955 return false; 956 957 // To be a got equivalent, at least one of its users need to be a constant 958 // expression used by another global variable. 959 for (auto *U : GV->users()) 960 NumGOTEquivUsers += getNumGlobalVariableUses(dyn_cast<Constant>(U)); 961 962 return NumGOTEquivUsers > 0; 963 } 964 965 /// \brief Unnamed constant global variables solely contaning a pointer to 966 /// another globals variable is equivalent to a GOT table entry; it contains the 967 /// the address of another symbol. Optimize it and replace accesses to these 968 /// "GOT equivalents" by using the GOT entry for the final global instead. 969 /// Compute GOT equivalent candidates among all global variables to avoid 970 /// emitting them if possible later on, after it use is replaced by a GOT entry 971 /// access. 972 void AsmPrinter::computeGlobalGOTEquivs(Module &M) { 973 if (!getObjFileLowering().supportIndirectSymViaGOTPCRel()) 974 return; 975 976 for (const auto &G : M.globals()) { 977 unsigned NumGOTEquivUsers = 0; 978 if (!isGOTEquivalentCandidate(&G, NumGOTEquivUsers)) 979 continue; 980 981 const MCSymbol *GOTEquivSym = getSymbol(&G); 982 GlobalGOTEquivs[GOTEquivSym] = std::make_pair(&G, NumGOTEquivUsers); 983 } 984 } 985 986 /// \brief Constant expressions using GOT equivalent globals may not be eligible 987 /// for PC relative GOT entry conversion, in such cases we need to emit such 988 /// globals we previously omitted in EmitGlobalVariable. 989 void AsmPrinter::emitGlobalGOTEquivs() { 990 if (!getObjFileLowering().supportIndirectSymViaGOTPCRel()) 991 return; 992 993 SmallVector<const GlobalVariable *, 8> FailedCandidates; 994 for (auto &I : GlobalGOTEquivs) { 995 const GlobalVariable *GV = I.second.first; 996 unsigned Cnt = I.second.second; 997 if (Cnt) 998 FailedCandidates.push_back(GV); 999 } 1000 GlobalGOTEquivs.clear(); 1001 1002 for (auto *GV : FailedCandidates) 1003 EmitGlobalVariable(GV); 1004 } 1005 1006 bool AsmPrinter::doFinalization(Module &M) { 1007 // Set the MachineFunction to nullptr so that we can catch attempted 1008 // accesses to MF specific features at the module level and so that 1009 // we can conditionalize accesses based on whether or not it is nullptr. 1010 MF = nullptr; 1011 1012 // Gather all GOT equivalent globals in the module. We really need two 1013 // passes over the globals: one to compute and another to avoid its emission 1014 // in EmitGlobalVariable, otherwise we would not be able to handle cases 1015 // where the got equivalent shows up before its use. 1016 computeGlobalGOTEquivs(M); 1017 1018 // Emit global variables. 1019 for (const auto &G : M.globals()) 1020 EmitGlobalVariable(&G); 1021 1022 // Emit remaining GOT equivalent globals. 1023 emitGlobalGOTEquivs(); 1024 1025 // Emit visibility info for declarations 1026 for (const Function &F : M) { 1027 if (!F.isDeclaration()) 1028 continue; 1029 GlobalValue::VisibilityTypes V = F.getVisibility(); 1030 if (V == GlobalValue::DefaultVisibility) 1031 continue; 1032 1033 MCSymbol *Name = getSymbol(&F); 1034 EmitVisibility(Name, V, false); 1035 } 1036 1037 const TargetLoweringObjectFile &TLOF = getObjFileLowering(); 1038 1039 // Emit module flags. 1040 SmallVector<Module::ModuleFlagEntry, 8> ModuleFlags; 1041 M.getModuleFlagsMetadata(ModuleFlags); 1042 if (!ModuleFlags.empty()) 1043 TLOF.emitModuleFlags(OutStreamer, ModuleFlags, *Mang, TM); 1044 1045 Triple TT(TM.getTargetTriple()); 1046 if (TT.isOSBinFormatELF()) { 1047 MachineModuleInfoELF &MMIELF = MMI->getObjFileInfo<MachineModuleInfoELF>(); 1048 1049 // Output stubs for external and common global variables. 1050 MachineModuleInfoELF::SymbolListTy Stubs = MMIELF.GetGVStubList(); 1051 if (!Stubs.empty()) { 1052 OutStreamer.SwitchSection(TLOF.getDataRelSection()); 1053 const DataLayout *DL = TM.getDataLayout(); 1054 1055 for (const auto &Stub : Stubs) { 1056 OutStreamer.EmitLabel(Stub.first); 1057 OutStreamer.EmitSymbolValue(Stub.second.getPointer(), 1058 DL->getPointerSize()); 1059 } 1060 } 1061 } 1062 1063 // Make sure we wrote out everything we need. 1064 OutStreamer.Flush(); 1065 1066 // Finalize debug and EH information. 1067 for (const HandlerInfo &HI : Handlers) { 1068 NamedRegionTimer T(HI.TimerName, HI.TimerGroupName, 1069 TimePassesIsEnabled); 1070 HI.Handler->endModule(); 1071 delete HI.Handler; 1072 } 1073 Handlers.clear(); 1074 DD = nullptr; 1075 1076 // If the target wants to know about weak references, print them all. 1077 if (MAI->getWeakRefDirective()) { 1078 // FIXME: This is not lazy, it would be nice to only print weak references 1079 // to stuff that is actually used. Note that doing so would require targets 1080 // to notice uses in operands (due to constant exprs etc). This should 1081 // happen with the MC stuff eventually. 1082 1083 // Print out module-level global variables here. 1084 for (const auto &G : M.globals()) { 1085 if (!G.hasExternalWeakLinkage()) 1086 continue; 1087 OutStreamer.EmitSymbolAttribute(getSymbol(&G), MCSA_WeakReference); 1088 } 1089 1090 for (const auto &F : M) { 1091 if (!F.hasExternalWeakLinkage()) 1092 continue; 1093 OutStreamer.EmitSymbolAttribute(getSymbol(&F), MCSA_WeakReference); 1094 } 1095 } 1096 1097 OutStreamer.AddBlankLine(); 1098 for (const auto &Alias : M.aliases()) { 1099 MCSymbol *Name = getSymbol(&Alias); 1100 1101 if (Alias.hasExternalLinkage() || !MAI->getWeakRefDirective()) 1102 OutStreamer.EmitSymbolAttribute(Name, MCSA_Global); 1103 else if (Alias.hasWeakLinkage() || Alias.hasLinkOnceLinkage()) 1104 OutStreamer.EmitSymbolAttribute(Name, MCSA_WeakReference); 1105 else 1106 assert(Alias.hasLocalLinkage() && "Invalid alias linkage"); 1107 1108 EmitVisibility(Name, Alias.getVisibility()); 1109 1110 // Emit the directives as assignments aka .set: 1111 OutStreamer.EmitAssignment(Name, lowerConstant(Alias.getAliasee())); 1112 } 1113 1114 GCModuleInfo *MI = getAnalysisIfAvailable<GCModuleInfo>(); 1115 assert(MI && "AsmPrinter didn't require GCModuleInfo?"); 1116 for (GCModuleInfo::iterator I = MI->end(), E = MI->begin(); I != E; ) 1117 if (GCMetadataPrinter *MP = GetOrCreateGCPrinter(**--I)) 1118 MP->finishAssembly(M, *MI, *this); 1119 1120 // Emit llvm.ident metadata in an '.ident' directive. 1121 EmitModuleIdents(M); 1122 1123 // Emit __morestack address if needed for indirect calls. 1124 if (MMI->usesMorestackAddr()) { 1125 const MCSection *ReadOnlySection = 1126 getObjFileLowering().getSectionForConstant(SectionKind::getReadOnly(), 1127 /*C=*/nullptr); 1128 OutStreamer.SwitchSection(ReadOnlySection); 1129 1130 MCSymbol *AddrSymbol = 1131 OutContext.GetOrCreateSymbol(StringRef("__morestack_addr")); 1132 OutStreamer.EmitLabel(AddrSymbol); 1133 1134 unsigned PtrSize = TM.getDataLayout()->getPointerSize(0); 1135 OutStreamer.EmitSymbolValue(GetExternalSymbolSymbol("__morestack"), 1136 PtrSize); 1137 } 1138 1139 // If we don't have any trampolines, then we don't require stack memory 1140 // to be executable. Some targets have a directive to declare this. 1141 Function *InitTrampolineIntrinsic = M.getFunction("llvm.init.trampoline"); 1142 if (!InitTrampolineIntrinsic || InitTrampolineIntrinsic->use_empty()) 1143 if (const MCSection *S = MAI->getNonexecutableStackSection(OutContext)) 1144 OutStreamer.SwitchSection(S); 1145 1146 // Allow the target to emit any magic that it wants at the end of the file, 1147 // after everything else has gone out. 1148 EmitEndOfAsmFile(M); 1149 1150 delete Mang; Mang = nullptr; 1151 MMI = nullptr; 1152 1153 OutStreamer.Finish(); 1154 OutStreamer.reset(); 1155 1156 return false; 1157 } 1158 1159 MCSymbol *AsmPrinter::getCurExceptionSym() { 1160 if (!CurExceptionSym) 1161 CurExceptionSym = createTempSymbol("exception"); 1162 return CurExceptionSym; 1163 } 1164 1165 void AsmPrinter::SetupMachineFunction(MachineFunction &MF) { 1166 this->MF = &MF; 1167 // Get the function symbol. 1168 CurrentFnSym = getSymbol(MF.getFunction()); 1169 CurrentFnSymForSize = CurrentFnSym; 1170 CurrentFnBegin = nullptr; 1171 CurExceptionSym = nullptr; 1172 bool NeedsLocalForSize = MAI->needsLocalForSize(); 1173 if (!MMI->getLandingPads().empty() || MMI->hasDebugInfo() || 1174 NeedsLocalForSize) { 1175 CurrentFnBegin = createTempSymbol("func_begin"); 1176 if (NeedsLocalForSize) 1177 CurrentFnSymForSize = CurrentFnBegin; 1178 } 1179 1180 if (isVerbose()) 1181 LI = &getAnalysis<MachineLoopInfo>(); 1182 } 1183 1184 namespace { 1185 // SectionCPs - Keep track the alignment, constpool entries per Section. 1186 struct SectionCPs { 1187 const MCSection *S; 1188 unsigned Alignment; 1189 SmallVector<unsigned, 4> CPEs; 1190 SectionCPs(const MCSection *s, unsigned a) : S(s), Alignment(a) {} 1191 }; 1192 } 1193 1194 /// EmitConstantPool - Print to the current output stream assembly 1195 /// representations of the constants in the constant pool MCP. This is 1196 /// used to print out constants which have been "spilled to memory" by 1197 /// the code generator. 1198 /// 1199 void AsmPrinter::EmitConstantPool() { 1200 const MachineConstantPool *MCP = MF->getConstantPool(); 1201 const std::vector<MachineConstantPoolEntry> &CP = MCP->getConstants(); 1202 if (CP.empty()) return; 1203 1204 // Calculate sections for constant pool entries. We collect entries to go into 1205 // the same section together to reduce amount of section switch statements. 1206 SmallVector<SectionCPs, 4> CPSections; 1207 for (unsigned i = 0, e = CP.size(); i != e; ++i) { 1208 const MachineConstantPoolEntry &CPE = CP[i]; 1209 unsigned Align = CPE.getAlignment(); 1210 1211 SectionKind Kind = 1212 CPE.getSectionKind(TM.getDataLayout()); 1213 1214 const Constant *C = nullptr; 1215 if (!CPE.isMachineConstantPoolEntry()) 1216 C = CPE.Val.ConstVal; 1217 1218 const MCSection *S = getObjFileLowering().getSectionForConstant(Kind, C); 1219 1220 // The number of sections are small, just do a linear search from the 1221 // last section to the first. 1222 bool Found = false; 1223 unsigned SecIdx = CPSections.size(); 1224 while (SecIdx != 0) { 1225 if (CPSections[--SecIdx].S == S) { 1226 Found = true; 1227 break; 1228 } 1229 } 1230 if (!Found) { 1231 SecIdx = CPSections.size(); 1232 CPSections.push_back(SectionCPs(S, Align)); 1233 } 1234 1235 if (Align > CPSections[SecIdx].Alignment) 1236 CPSections[SecIdx].Alignment = Align; 1237 CPSections[SecIdx].CPEs.push_back(i); 1238 } 1239 1240 // Now print stuff into the calculated sections. 1241 const MCSection *CurSection = nullptr; 1242 unsigned Offset = 0; 1243 for (unsigned i = 0, e = CPSections.size(); i != e; ++i) { 1244 for (unsigned j = 0, ee = CPSections[i].CPEs.size(); j != ee; ++j) { 1245 unsigned CPI = CPSections[i].CPEs[j]; 1246 MCSymbol *Sym = GetCPISymbol(CPI); 1247 if (!Sym->isUndefined()) 1248 continue; 1249 1250 if (CurSection != CPSections[i].S) { 1251 OutStreamer.SwitchSection(CPSections[i].S); 1252 EmitAlignment(Log2_32(CPSections[i].Alignment)); 1253 CurSection = CPSections[i].S; 1254 Offset = 0; 1255 } 1256 1257 MachineConstantPoolEntry CPE = CP[CPI]; 1258 1259 // Emit inter-object padding for alignment. 1260 unsigned AlignMask = CPE.getAlignment() - 1; 1261 unsigned NewOffset = (Offset + AlignMask) & ~AlignMask; 1262 OutStreamer.EmitZeros(NewOffset - Offset); 1263 1264 Type *Ty = CPE.getType(); 1265 Offset = NewOffset + 1266 TM.getDataLayout()->getTypeAllocSize(Ty); 1267 1268 OutStreamer.EmitLabel(Sym); 1269 if (CPE.isMachineConstantPoolEntry()) 1270 EmitMachineConstantPoolValue(CPE.Val.MachineCPVal); 1271 else 1272 EmitGlobalConstant(CPE.Val.ConstVal); 1273 } 1274 } 1275 } 1276 1277 /// EmitJumpTableInfo - Print assembly representations of the jump tables used 1278 /// by the current function to the current output stream. 1279 /// 1280 void AsmPrinter::EmitJumpTableInfo() { 1281 const DataLayout *DL = MF->getTarget().getDataLayout(); 1282 const MachineJumpTableInfo *MJTI = MF->getJumpTableInfo(); 1283 if (!MJTI) return; 1284 if (MJTI->getEntryKind() == MachineJumpTableInfo::EK_Inline) return; 1285 const std::vector<MachineJumpTableEntry> &JT = MJTI->getJumpTables(); 1286 if (JT.empty()) return; 1287 1288 // Pick the directive to use to print the jump table entries, and switch to 1289 // the appropriate section. 1290 const Function *F = MF->getFunction(); 1291 const TargetLoweringObjectFile &TLOF = getObjFileLowering(); 1292 bool JTInDiffSection = !TLOF.shouldPutJumpTableInFunctionSection( 1293 MJTI->getEntryKind() == MachineJumpTableInfo::EK_LabelDifference32, 1294 *F); 1295 if (JTInDiffSection) { 1296 // Drop it in the readonly section. 1297 const MCSection *ReadOnlySection = 1298 TLOF.getSectionForJumpTable(*F, *Mang, TM); 1299 OutStreamer.SwitchSection(ReadOnlySection); 1300 } 1301 1302 EmitAlignment(Log2_32( 1303 MJTI->getEntryAlignment(*TM.getDataLayout()))); 1304 1305 // Jump tables in code sections are marked with a data_region directive 1306 // where that's supported. 1307 if (!JTInDiffSection) 1308 OutStreamer.EmitDataRegion(MCDR_DataRegionJT32); 1309 1310 for (unsigned JTI = 0, e = JT.size(); JTI != e; ++JTI) { 1311 const std::vector<MachineBasicBlock*> &JTBBs = JT[JTI].MBBs; 1312 1313 // If this jump table was deleted, ignore it. 1314 if (JTBBs.empty()) continue; 1315 1316 // For the EK_LabelDifference32 entry, if using .set avoids a relocation, 1317 /// emit a .set directive for each unique entry. 1318 if (MJTI->getEntryKind() == MachineJumpTableInfo::EK_LabelDifference32 && 1319 MAI->doesSetDirectiveSuppressesReloc()) { 1320 SmallPtrSet<const MachineBasicBlock*, 16> EmittedSets; 1321 const TargetLowering *TLI = MF->getSubtarget().getTargetLowering(); 1322 const MCExpr *Base = TLI->getPICJumpTableRelocBaseExpr(MF,JTI,OutContext); 1323 for (unsigned ii = 0, ee = JTBBs.size(); ii != ee; ++ii) { 1324 const MachineBasicBlock *MBB = JTBBs[ii]; 1325 if (!EmittedSets.insert(MBB).second) 1326 continue; 1327 1328 // .set LJTSet, LBB32-base 1329 const MCExpr *LHS = 1330 MCSymbolRefExpr::Create(MBB->getSymbol(), OutContext); 1331 OutStreamer.EmitAssignment(GetJTSetSymbol(JTI, MBB->getNumber()), 1332 MCBinaryExpr::CreateSub(LHS, Base, OutContext)); 1333 } 1334 } 1335 1336 // On some targets (e.g. Darwin) we want to emit two consecutive labels 1337 // before each jump table. The first label is never referenced, but tells 1338 // the assembler and linker the extents of the jump table object. The 1339 // second label is actually referenced by the code. 1340 if (JTInDiffSection && DL->hasLinkerPrivateGlobalPrefix()) 1341 // FIXME: This doesn't have to have any specific name, just any randomly 1342 // named and numbered 'l' label would work. Simplify GetJTISymbol. 1343 OutStreamer.EmitLabel(GetJTISymbol(JTI, true)); 1344 1345 OutStreamer.EmitLabel(GetJTISymbol(JTI)); 1346 1347 for (unsigned ii = 0, ee = JTBBs.size(); ii != ee; ++ii) 1348 EmitJumpTableEntry(MJTI, JTBBs[ii], JTI); 1349 } 1350 if (!JTInDiffSection) 1351 OutStreamer.EmitDataRegion(MCDR_DataRegionEnd); 1352 } 1353 1354 /// EmitJumpTableEntry - Emit a jump table entry for the specified MBB to the 1355 /// current stream. 1356 void AsmPrinter::EmitJumpTableEntry(const MachineJumpTableInfo *MJTI, 1357 const MachineBasicBlock *MBB, 1358 unsigned UID) const { 1359 assert(MBB && MBB->getNumber() >= 0 && "Invalid basic block"); 1360 const MCExpr *Value = nullptr; 1361 switch (MJTI->getEntryKind()) { 1362 case MachineJumpTableInfo::EK_Inline: 1363 llvm_unreachable("Cannot emit EK_Inline jump table entry"); 1364 case MachineJumpTableInfo::EK_Custom32: 1365 Value = MF->getSubtarget().getTargetLowering()->LowerCustomJumpTableEntry( 1366 MJTI, MBB, UID, OutContext); 1367 break; 1368 case MachineJumpTableInfo::EK_BlockAddress: 1369 // EK_BlockAddress - Each entry is a plain address of block, e.g.: 1370 // .word LBB123 1371 Value = MCSymbolRefExpr::Create(MBB->getSymbol(), OutContext); 1372 break; 1373 case MachineJumpTableInfo::EK_GPRel32BlockAddress: { 1374 // EK_GPRel32BlockAddress - Each entry is an address of block, encoded 1375 // with a relocation as gp-relative, e.g.: 1376 // .gprel32 LBB123 1377 MCSymbol *MBBSym = MBB->getSymbol(); 1378 OutStreamer.EmitGPRel32Value(MCSymbolRefExpr::Create(MBBSym, OutContext)); 1379 return; 1380 } 1381 1382 case MachineJumpTableInfo::EK_GPRel64BlockAddress: { 1383 // EK_GPRel64BlockAddress - Each entry is an address of block, encoded 1384 // with a relocation as gp-relative, e.g.: 1385 // .gpdword LBB123 1386 MCSymbol *MBBSym = MBB->getSymbol(); 1387 OutStreamer.EmitGPRel64Value(MCSymbolRefExpr::Create(MBBSym, OutContext)); 1388 return; 1389 } 1390 1391 case MachineJumpTableInfo::EK_LabelDifference32: { 1392 // Each entry is the address of the block minus the address of the jump 1393 // table. This is used for PIC jump tables where gprel32 is not supported. 1394 // e.g.: 1395 // .word LBB123 - LJTI1_2 1396 // If the .set directive avoids relocations, this is emitted as: 1397 // .set L4_5_set_123, LBB123 - LJTI1_2 1398 // .word L4_5_set_123 1399 if (MAI->doesSetDirectiveSuppressesReloc()) { 1400 Value = MCSymbolRefExpr::Create(GetJTSetSymbol(UID, MBB->getNumber()), 1401 OutContext); 1402 break; 1403 } 1404 Value = MCSymbolRefExpr::Create(MBB->getSymbol(), OutContext); 1405 const TargetLowering *TLI = MF->getSubtarget().getTargetLowering(); 1406 const MCExpr *Base = TLI->getPICJumpTableRelocBaseExpr(MF, UID, OutContext); 1407 Value = MCBinaryExpr::CreateSub(Value, Base, OutContext); 1408 break; 1409 } 1410 } 1411 1412 assert(Value && "Unknown entry kind!"); 1413 1414 unsigned EntrySize = 1415 MJTI->getEntrySize(*TM.getDataLayout()); 1416 OutStreamer.EmitValue(Value, EntrySize); 1417 } 1418 1419 1420 /// EmitSpecialLLVMGlobal - Check to see if the specified global is a 1421 /// special global used by LLVM. If so, emit it and return true, otherwise 1422 /// do nothing and return false. 1423 bool AsmPrinter::EmitSpecialLLVMGlobal(const GlobalVariable *GV) { 1424 if (GV->getName() == "llvm.used") { 1425 if (MAI->hasNoDeadStrip()) // No need to emit this at all. 1426 EmitLLVMUsedList(cast<ConstantArray>(GV->getInitializer())); 1427 return true; 1428 } 1429 1430 // Ignore debug and non-emitted data. This handles llvm.compiler.used. 1431 if (StringRef(GV->getSection()) == "llvm.metadata" || 1432 GV->hasAvailableExternallyLinkage()) 1433 return true; 1434 1435 if (!GV->hasAppendingLinkage()) return false; 1436 1437 assert(GV->hasInitializer() && "Not a special LLVM global!"); 1438 1439 if (GV->getName() == "llvm.global_ctors") { 1440 EmitXXStructorList(GV->getInitializer(), /* isCtor */ true); 1441 1442 if (TM.getRelocationModel() == Reloc::Static && 1443 MAI->hasStaticCtorDtorReferenceInStaticMode()) { 1444 StringRef Sym(".constructors_used"); 1445 OutStreamer.EmitSymbolAttribute(OutContext.GetOrCreateSymbol(Sym), 1446 MCSA_Reference); 1447 } 1448 return true; 1449 } 1450 1451 if (GV->getName() == "llvm.global_dtors") { 1452 EmitXXStructorList(GV->getInitializer(), /* isCtor */ false); 1453 1454 if (TM.getRelocationModel() == Reloc::Static && 1455 MAI->hasStaticCtorDtorReferenceInStaticMode()) { 1456 StringRef Sym(".destructors_used"); 1457 OutStreamer.EmitSymbolAttribute(OutContext.GetOrCreateSymbol(Sym), 1458 MCSA_Reference); 1459 } 1460 return true; 1461 } 1462 1463 return false; 1464 } 1465 1466 /// EmitLLVMUsedList - For targets that define a MAI::UsedDirective, mark each 1467 /// global in the specified llvm.used list for which emitUsedDirectiveFor 1468 /// is true, as being used with this directive. 1469 void AsmPrinter::EmitLLVMUsedList(const ConstantArray *InitList) { 1470 // Should be an array of 'i8*'. 1471 for (unsigned i = 0, e = InitList->getNumOperands(); i != e; ++i) { 1472 const GlobalValue *GV = 1473 dyn_cast<GlobalValue>(InitList->getOperand(i)->stripPointerCasts()); 1474 if (GV) 1475 OutStreamer.EmitSymbolAttribute(getSymbol(GV), MCSA_NoDeadStrip); 1476 } 1477 } 1478 1479 namespace { 1480 struct Structor { 1481 Structor() : Priority(0), Func(nullptr), ComdatKey(nullptr) {} 1482 int Priority; 1483 llvm::Constant *Func; 1484 llvm::GlobalValue *ComdatKey; 1485 }; 1486 } // end namespace 1487 1488 /// EmitXXStructorList - Emit the ctor or dtor list taking into account the init 1489 /// priority. 1490 void AsmPrinter::EmitXXStructorList(const Constant *List, bool isCtor) { 1491 // Should be an array of '{ int, void ()* }' structs. The first value is the 1492 // init priority. 1493 if (!isa<ConstantArray>(List)) return; 1494 1495 // Sanity check the structors list. 1496 const ConstantArray *InitList = dyn_cast<ConstantArray>(List); 1497 if (!InitList) return; // Not an array! 1498 StructType *ETy = dyn_cast<StructType>(InitList->getType()->getElementType()); 1499 // FIXME: Only allow the 3-field form in LLVM 4.0. 1500 if (!ETy || ETy->getNumElements() < 2 || ETy->getNumElements() > 3) 1501 return; // Not an array of two or three elements! 1502 if (!isa<IntegerType>(ETy->getTypeAtIndex(0U)) || 1503 !isa<PointerType>(ETy->getTypeAtIndex(1U))) return; // Not (int, ptr). 1504 if (ETy->getNumElements() == 3 && !isa<PointerType>(ETy->getTypeAtIndex(2U))) 1505 return; // Not (int, ptr, ptr). 1506 1507 // Gather the structors in a form that's convenient for sorting by priority. 1508 SmallVector<Structor, 8> Structors; 1509 for (Value *O : InitList->operands()) { 1510 ConstantStruct *CS = dyn_cast<ConstantStruct>(O); 1511 if (!CS) continue; // Malformed. 1512 if (CS->getOperand(1)->isNullValue()) 1513 break; // Found a null terminator, skip the rest. 1514 ConstantInt *Priority = dyn_cast<ConstantInt>(CS->getOperand(0)); 1515 if (!Priority) continue; // Malformed. 1516 Structors.push_back(Structor()); 1517 Structor &S = Structors.back(); 1518 S.Priority = Priority->getLimitedValue(65535); 1519 S.Func = CS->getOperand(1); 1520 if (ETy->getNumElements() == 3 && !CS->getOperand(2)->isNullValue()) 1521 S.ComdatKey = dyn_cast<GlobalValue>(CS->getOperand(2)->stripPointerCasts()); 1522 } 1523 1524 // Emit the function pointers in the target-specific order 1525 const DataLayout *DL = TM.getDataLayout(); 1526 unsigned Align = Log2_32(DL->getPointerPrefAlignment()); 1527 std::stable_sort(Structors.begin(), Structors.end(), 1528 [](const Structor &L, 1529 const Structor &R) { return L.Priority < R.Priority; }); 1530 for (Structor &S : Structors) { 1531 const TargetLoweringObjectFile &Obj = getObjFileLowering(); 1532 const MCSymbol *KeySym = nullptr; 1533 if (GlobalValue *GV = S.ComdatKey) { 1534 if (GV->hasAvailableExternallyLinkage()) 1535 // If the associated variable is available_externally, some other TU 1536 // will provide its dynamic initializer. 1537 continue; 1538 1539 KeySym = getSymbol(GV); 1540 } 1541 const MCSection *OutputSection = 1542 (isCtor ? Obj.getStaticCtorSection(S.Priority, KeySym) 1543 : Obj.getStaticDtorSection(S.Priority, KeySym)); 1544 OutStreamer.SwitchSection(OutputSection); 1545 if (OutStreamer.getCurrentSection() != OutStreamer.getPreviousSection()) 1546 EmitAlignment(Align); 1547 EmitXXStructor(S.Func); 1548 } 1549 } 1550 1551 void AsmPrinter::EmitModuleIdents(Module &M) { 1552 if (!MAI->hasIdentDirective()) 1553 return; 1554 1555 if (const NamedMDNode *NMD = M.getNamedMetadata("llvm.ident")) { 1556 for (unsigned i = 0, e = NMD->getNumOperands(); i != e; ++i) { 1557 const MDNode *N = NMD->getOperand(i); 1558 assert(N->getNumOperands() == 1 && 1559 "llvm.ident metadata entry can have only one operand"); 1560 const MDString *S = cast<MDString>(N->getOperand(0)); 1561 OutStreamer.EmitIdent(S->getString()); 1562 } 1563 } 1564 } 1565 1566 //===--------------------------------------------------------------------===// 1567 // Emission and print routines 1568 // 1569 1570 /// EmitInt8 - Emit a byte directive and value. 1571 /// 1572 void AsmPrinter::EmitInt8(int Value) const { 1573 OutStreamer.EmitIntValue(Value, 1); 1574 } 1575 1576 /// EmitInt16 - Emit a short directive and value. 1577 /// 1578 void AsmPrinter::EmitInt16(int Value) const { 1579 OutStreamer.EmitIntValue(Value, 2); 1580 } 1581 1582 /// EmitInt32 - Emit a long directive and value. 1583 /// 1584 void AsmPrinter::EmitInt32(int Value) const { 1585 OutStreamer.EmitIntValue(Value, 4); 1586 } 1587 1588 /// Emit something like ".long Hi-Lo" where the size in bytes of the directive 1589 /// is specified by Size and Hi/Lo specify the labels. This implicitly uses 1590 /// .set if it avoids relocations. 1591 void AsmPrinter::EmitLabelDifference(const MCSymbol *Hi, const MCSymbol *Lo, 1592 unsigned Size) const { 1593 // Get the Hi-Lo expression. 1594 const MCExpr *Diff = 1595 MCBinaryExpr::CreateSub(MCSymbolRefExpr::Create(Hi, OutContext), 1596 MCSymbolRefExpr::Create(Lo, OutContext), 1597 OutContext); 1598 1599 if (!MAI->doesSetDirectiveSuppressesReloc()) { 1600 OutStreamer.EmitValue(Diff, Size); 1601 return; 1602 } 1603 1604 // Otherwise, emit with .set (aka assignment). 1605 MCSymbol *SetLabel = createTempSymbol("set"); 1606 OutStreamer.EmitAssignment(SetLabel, Diff); 1607 OutStreamer.EmitSymbolValue(SetLabel, Size); 1608 } 1609 1610 /// EmitLabelPlusOffset - Emit something like ".long Label+Offset" 1611 /// where the size in bytes of the directive is specified by Size and Label 1612 /// specifies the label. This implicitly uses .set if it is available. 1613 void AsmPrinter::EmitLabelPlusOffset(const MCSymbol *Label, uint64_t Offset, 1614 unsigned Size, 1615 bool IsSectionRelative) const { 1616 if (MAI->needsDwarfSectionOffsetDirective() && IsSectionRelative) { 1617 OutStreamer.EmitCOFFSecRel32(Label); 1618 return; 1619 } 1620 1621 // Emit Label+Offset (or just Label if Offset is zero) 1622 const MCExpr *Expr = MCSymbolRefExpr::Create(Label, OutContext); 1623 if (Offset) 1624 Expr = MCBinaryExpr::CreateAdd( 1625 Expr, MCConstantExpr::Create(Offset, OutContext), OutContext); 1626 1627 OutStreamer.EmitValue(Expr, Size); 1628 } 1629 1630 //===----------------------------------------------------------------------===// 1631 1632 // EmitAlignment - Emit an alignment directive to the specified power of 1633 // two boundary. For example, if you pass in 3 here, you will get an 8 1634 // byte alignment. If a global value is specified, and if that global has 1635 // an explicit alignment requested, it will override the alignment request 1636 // if required for correctness. 1637 // 1638 void AsmPrinter::EmitAlignment(unsigned NumBits, const GlobalObject *GV) const { 1639 if (GV) 1640 NumBits = getGVAlignmentLog2(GV, *TM.getDataLayout(), 1641 NumBits); 1642 1643 if (NumBits == 0) return; // 1-byte aligned: no need to emit alignment. 1644 1645 assert(NumBits < 1646 static_cast<unsigned>(std::numeric_limits<unsigned>::digits) && 1647 "undefined behavior"); 1648 if (getCurrentSection()->getKind().isText()) 1649 OutStreamer.EmitCodeAlignment(1u << NumBits); 1650 else 1651 OutStreamer.EmitValueToAlignment(1u << NumBits); 1652 } 1653 1654 //===----------------------------------------------------------------------===// 1655 // Constant emission. 1656 //===----------------------------------------------------------------------===// 1657 1658 const MCExpr *AsmPrinter::lowerConstant(const Constant *CV) { 1659 MCContext &Ctx = OutContext; 1660 1661 if (CV->isNullValue() || isa<UndefValue>(CV)) 1662 return MCConstantExpr::Create(0, Ctx); 1663 1664 if (const ConstantInt *CI = dyn_cast<ConstantInt>(CV)) 1665 return MCConstantExpr::Create(CI->getZExtValue(), Ctx); 1666 1667 if (const GlobalValue *GV = dyn_cast<GlobalValue>(CV)) 1668 return MCSymbolRefExpr::Create(getSymbol(GV), Ctx); 1669 1670 if (const BlockAddress *BA = dyn_cast<BlockAddress>(CV)) 1671 return MCSymbolRefExpr::Create(GetBlockAddressSymbol(BA), Ctx); 1672 1673 const ConstantExpr *CE = dyn_cast<ConstantExpr>(CV); 1674 if (!CE) { 1675 llvm_unreachable("Unknown constant value to lower!"); 1676 } 1677 1678 if (const MCExpr *RelocExpr 1679 = getObjFileLowering().getExecutableRelativeSymbol(CE, *Mang, TM)) 1680 return RelocExpr; 1681 1682 switch (CE->getOpcode()) { 1683 default: 1684 // If the code isn't optimized, there may be outstanding folding 1685 // opportunities. Attempt to fold the expression using DataLayout as a 1686 // last resort before giving up. 1687 if (Constant *C = ConstantFoldConstantExpression(CE, *TM.getDataLayout())) 1688 if (C != CE) 1689 return lowerConstant(C); 1690 1691 // Otherwise report the problem to the user. 1692 { 1693 std::string S; 1694 raw_string_ostream OS(S); 1695 OS << "Unsupported expression in static initializer: "; 1696 CE->printAsOperand(OS, /*PrintType=*/false, 1697 !MF ? nullptr : MF->getFunction()->getParent()); 1698 report_fatal_error(OS.str()); 1699 } 1700 case Instruction::GetElementPtr: { 1701 const DataLayout &DL = *TM.getDataLayout(); 1702 1703 // Generate a symbolic expression for the byte address 1704 APInt OffsetAI(DL.getPointerTypeSizeInBits(CE->getType()), 0); 1705 cast<GEPOperator>(CE)->accumulateConstantOffset(DL, OffsetAI); 1706 1707 const MCExpr *Base = lowerConstant(CE->getOperand(0)); 1708 if (!OffsetAI) 1709 return Base; 1710 1711 int64_t Offset = OffsetAI.getSExtValue(); 1712 return MCBinaryExpr::CreateAdd(Base, MCConstantExpr::Create(Offset, Ctx), 1713 Ctx); 1714 } 1715 1716 case Instruction::Trunc: 1717 // We emit the value and depend on the assembler to truncate the generated 1718 // expression properly. This is important for differences between 1719 // blockaddress labels. Since the two labels are in the same function, it 1720 // is reasonable to treat their delta as a 32-bit value. 1721 // FALL THROUGH. 1722 case Instruction::BitCast: 1723 return lowerConstant(CE->getOperand(0)); 1724 1725 case Instruction::IntToPtr: { 1726 const DataLayout &DL = *TM.getDataLayout(); 1727 1728 // Handle casts to pointers by changing them into casts to the appropriate 1729 // integer type. This promotes constant folding and simplifies this code. 1730 Constant *Op = CE->getOperand(0); 1731 Op = ConstantExpr::getIntegerCast(Op, DL.getIntPtrType(CV->getType()), 1732 false/*ZExt*/); 1733 return lowerConstant(Op); 1734 } 1735 1736 case Instruction::PtrToInt: { 1737 const DataLayout &DL = *TM.getDataLayout(); 1738 1739 // Support only foldable casts to/from pointers that can be eliminated by 1740 // changing the pointer to the appropriately sized integer type. 1741 Constant *Op = CE->getOperand(0); 1742 Type *Ty = CE->getType(); 1743 1744 const MCExpr *OpExpr = lowerConstant(Op); 1745 1746 // We can emit the pointer value into this slot if the slot is an 1747 // integer slot equal to the size of the pointer. 1748 if (DL.getTypeAllocSize(Ty) == DL.getTypeAllocSize(Op->getType())) 1749 return OpExpr; 1750 1751 // Otherwise the pointer is smaller than the resultant integer, mask off 1752 // the high bits so we are sure to get a proper truncation if the input is 1753 // a constant expr. 1754 unsigned InBits = DL.getTypeAllocSizeInBits(Op->getType()); 1755 const MCExpr *MaskExpr = MCConstantExpr::Create(~0ULL >> (64-InBits), Ctx); 1756 return MCBinaryExpr::CreateAnd(OpExpr, MaskExpr, Ctx); 1757 } 1758 1759 // The MC library also has a right-shift operator, but it isn't consistently 1760 // signed or unsigned between different targets. 1761 case Instruction::Add: 1762 case Instruction::Sub: 1763 case Instruction::Mul: 1764 case Instruction::SDiv: 1765 case Instruction::SRem: 1766 case Instruction::Shl: 1767 case Instruction::And: 1768 case Instruction::Or: 1769 case Instruction::Xor: { 1770 const MCExpr *LHS = lowerConstant(CE->getOperand(0)); 1771 const MCExpr *RHS = lowerConstant(CE->getOperand(1)); 1772 switch (CE->getOpcode()) { 1773 default: llvm_unreachable("Unknown binary operator constant cast expr"); 1774 case Instruction::Add: return MCBinaryExpr::CreateAdd(LHS, RHS, Ctx); 1775 case Instruction::Sub: return MCBinaryExpr::CreateSub(LHS, RHS, Ctx); 1776 case Instruction::Mul: return MCBinaryExpr::CreateMul(LHS, RHS, Ctx); 1777 case Instruction::SDiv: return MCBinaryExpr::CreateDiv(LHS, RHS, Ctx); 1778 case Instruction::SRem: return MCBinaryExpr::CreateMod(LHS, RHS, Ctx); 1779 case Instruction::Shl: return MCBinaryExpr::CreateShl(LHS, RHS, Ctx); 1780 case Instruction::And: return MCBinaryExpr::CreateAnd(LHS, RHS, Ctx); 1781 case Instruction::Or: return MCBinaryExpr::CreateOr (LHS, RHS, Ctx); 1782 case Instruction::Xor: return MCBinaryExpr::CreateXor(LHS, RHS, Ctx); 1783 } 1784 } 1785 } 1786 } 1787 1788 static void emitGlobalConstantImpl(const Constant *C, AsmPrinter &AP, 1789 const Constant *BaseCV = nullptr, 1790 uint64_t Offset = 0); 1791 1792 /// isRepeatedByteSequence - Determine whether the given value is 1793 /// composed of a repeated sequence of identical bytes and return the 1794 /// byte value. If it is not a repeated sequence, return -1. 1795 static int isRepeatedByteSequence(const ConstantDataSequential *V) { 1796 StringRef Data = V->getRawDataValues(); 1797 assert(!Data.empty() && "Empty aggregates should be CAZ node"); 1798 char C = Data[0]; 1799 for (unsigned i = 1, e = Data.size(); i != e; ++i) 1800 if (Data[i] != C) return -1; 1801 return static_cast<uint8_t>(C); // Ensure 255 is not returned as -1. 1802 } 1803 1804 1805 /// isRepeatedByteSequence - Determine whether the given value is 1806 /// composed of a repeated sequence of identical bytes and return the 1807 /// byte value. If it is not a repeated sequence, return -1. 1808 static int isRepeatedByteSequence(const Value *V, TargetMachine &TM) { 1809 1810 if (const ConstantInt *CI = dyn_cast<ConstantInt>(V)) { 1811 if (CI->getBitWidth() > 64) return -1; 1812 1813 uint64_t Size = 1814 TM.getDataLayout()->getTypeAllocSize(V->getType()); 1815 uint64_t Value = CI->getZExtValue(); 1816 1817 // Make sure the constant is at least 8 bits long and has a power 1818 // of 2 bit width. This guarantees the constant bit width is 1819 // always a multiple of 8 bits, avoiding issues with padding out 1820 // to Size and other such corner cases. 1821 if (CI->getBitWidth() < 8 || !isPowerOf2_64(CI->getBitWidth())) return -1; 1822 1823 uint8_t Byte = static_cast<uint8_t>(Value); 1824 1825 for (unsigned i = 1; i < Size; ++i) { 1826 Value >>= 8; 1827 if (static_cast<uint8_t>(Value) != Byte) return -1; 1828 } 1829 return Byte; 1830 } 1831 if (const ConstantArray *CA = dyn_cast<ConstantArray>(V)) { 1832 // Make sure all array elements are sequences of the same repeated 1833 // byte. 1834 assert(CA->getNumOperands() != 0 && "Should be a CAZ"); 1835 int Byte = isRepeatedByteSequence(CA->getOperand(0), TM); 1836 if (Byte == -1) return -1; 1837 1838 for (unsigned i = 1, e = CA->getNumOperands(); i != e; ++i) { 1839 int ThisByte = isRepeatedByteSequence(CA->getOperand(i), TM); 1840 if (ThisByte == -1) return -1; 1841 if (Byte != ThisByte) return -1; 1842 } 1843 return Byte; 1844 } 1845 1846 if (const ConstantDataSequential *CDS = dyn_cast<ConstantDataSequential>(V)) 1847 return isRepeatedByteSequence(CDS); 1848 1849 return -1; 1850 } 1851 1852 static void emitGlobalConstantDataSequential(const ConstantDataSequential *CDS, 1853 AsmPrinter &AP){ 1854 1855 // See if we can aggregate this into a .fill, if so, emit it as such. 1856 int Value = isRepeatedByteSequence(CDS, AP.TM); 1857 if (Value != -1) { 1858 uint64_t Bytes = 1859 AP.TM.getDataLayout()->getTypeAllocSize( 1860 CDS->getType()); 1861 // Don't emit a 1-byte object as a .fill. 1862 if (Bytes > 1) 1863 return AP.OutStreamer.EmitFill(Bytes, Value); 1864 } 1865 1866 // If this can be emitted with .ascii/.asciz, emit it as such. 1867 if (CDS->isString()) 1868 return AP.OutStreamer.EmitBytes(CDS->getAsString()); 1869 1870 // Otherwise, emit the values in successive locations. 1871 unsigned ElementByteSize = CDS->getElementByteSize(); 1872 if (isa<IntegerType>(CDS->getElementType())) { 1873 for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i) { 1874 if (AP.isVerbose()) 1875 AP.OutStreamer.GetCommentOS() << format("0x%" PRIx64 "\n", 1876 CDS->getElementAsInteger(i)); 1877 AP.OutStreamer.EmitIntValue(CDS->getElementAsInteger(i), 1878 ElementByteSize); 1879 } 1880 } else if (ElementByteSize == 4) { 1881 // FP Constants are printed as integer constants to avoid losing 1882 // precision. 1883 assert(CDS->getElementType()->isFloatTy()); 1884 for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i) { 1885 union { 1886 float F; 1887 uint32_t I; 1888 }; 1889 1890 F = CDS->getElementAsFloat(i); 1891 if (AP.isVerbose()) 1892 AP.OutStreamer.GetCommentOS() << "float " << F << '\n'; 1893 AP.OutStreamer.EmitIntValue(I, 4); 1894 } 1895 } else { 1896 assert(CDS->getElementType()->isDoubleTy()); 1897 for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i) { 1898 union { 1899 double F; 1900 uint64_t I; 1901 }; 1902 1903 F = CDS->getElementAsDouble(i); 1904 if (AP.isVerbose()) 1905 AP.OutStreamer.GetCommentOS() << "double " << F << '\n'; 1906 AP.OutStreamer.EmitIntValue(I, 8); 1907 } 1908 } 1909 1910 const DataLayout &DL = *AP.TM.getDataLayout(); 1911 unsigned Size = DL.getTypeAllocSize(CDS->getType()); 1912 unsigned EmittedSize = DL.getTypeAllocSize(CDS->getType()->getElementType()) * 1913 CDS->getNumElements(); 1914 if (unsigned Padding = Size - EmittedSize) 1915 AP.OutStreamer.EmitZeros(Padding); 1916 1917 } 1918 1919 static void emitGlobalConstantArray(const ConstantArray *CA, AsmPrinter &AP, 1920 const Constant *BaseCV, uint64_t Offset) { 1921 // See if we can aggregate some values. Make sure it can be 1922 // represented as a series of bytes of the constant value. 1923 int Value = isRepeatedByteSequence(CA, AP.TM); 1924 const DataLayout &DL = *AP.TM.getDataLayout(); 1925 1926 if (Value != -1) { 1927 uint64_t Bytes = DL.getTypeAllocSize(CA->getType()); 1928 AP.OutStreamer.EmitFill(Bytes, Value); 1929 } 1930 else { 1931 for (unsigned i = 0, e = CA->getNumOperands(); i != e; ++i) { 1932 emitGlobalConstantImpl(CA->getOperand(i), AP, BaseCV, Offset); 1933 Offset += DL.getTypeAllocSize(CA->getOperand(i)->getType()); 1934 } 1935 } 1936 } 1937 1938 static void emitGlobalConstantVector(const ConstantVector *CV, AsmPrinter &AP) { 1939 for (unsigned i = 0, e = CV->getType()->getNumElements(); i != e; ++i) 1940 emitGlobalConstantImpl(CV->getOperand(i), AP); 1941 1942 const DataLayout &DL = *AP.TM.getDataLayout(); 1943 unsigned Size = DL.getTypeAllocSize(CV->getType()); 1944 unsigned EmittedSize = DL.getTypeAllocSize(CV->getType()->getElementType()) * 1945 CV->getType()->getNumElements(); 1946 if (unsigned Padding = Size - EmittedSize) 1947 AP.OutStreamer.EmitZeros(Padding); 1948 } 1949 1950 static void emitGlobalConstantStruct(const ConstantStruct *CS, AsmPrinter &AP, 1951 const Constant *BaseCV, uint64_t Offset) { 1952 // Print the fields in successive locations. Pad to align if needed! 1953 const DataLayout *DL = AP.TM.getDataLayout(); 1954 unsigned Size = DL->getTypeAllocSize(CS->getType()); 1955 const StructLayout *Layout = DL->getStructLayout(CS->getType()); 1956 uint64_t SizeSoFar = 0; 1957 for (unsigned i = 0, e = CS->getNumOperands(); i != e; ++i) { 1958 const Constant *Field = CS->getOperand(i); 1959 1960 // Print the actual field value. 1961 emitGlobalConstantImpl(Field, AP, BaseCV, Offset+SizeSoFar); 1962 1963 // Check if padding is needed and insert one or more 0s. 1964 uint64_t FieldSize = DL->getTypeAllocSize(Field->getType()); 1965 uint64_t PadSize = ((i == e-1 ? Size : Layout->getElementOffset(i+1)) 1966 - Layout->getElementOffset(i)) - FieldSize; 1967 SizeSoFar += FieldSize + PadSize; 1968 1969 // Insert padding - this may include padding to increase the size of the 1970 // current field up to the ABI size (if the struct is not packed) as well 1971 // as padding to ensure that the next field starts at the right offset. 1972 AP.OutStreamer.EmitZeros(PadSize); 1973 } 1974 assert(SizeSoFar == Layout->getSizeInBytes() && 1975 "Layout of constant struct may be incorrect!"); 1976 } 1977 1978 static void emitGlobalConstantFP(const ConstantFP *CFP, AsmPrinter &AP) { 1979 APInt API = CFP->getValueAPF().bitcastToAPInt(); 1980 1981 // First print a comment with what we think the original floating-point value 1982 // should have been. 1983 if (AP.isVerbose()) { 1984 SmallString<8> StrVal; 1985 CFP->getValueAPF().toString(StrVal); 1986 1987 if (CFP->getType()) 1988 CFP->getType()->print(AP.OutStreamer.GetCommentOS()); 1989 else 1990 AP.OutStreamer.GetCommentOS() << "Printing <null> Type"; 1991 AP.OutStreamer.GetCommentOS() << ' ' << StrVal << '\n'; 1992 } 1993 1994 // Now iterate through the APInt chunks, emitting them in endian-correct 1995 // order, possibly with a smaller chunk at beginning/end (e.g. for x87 80-bit 1996 // floats). 1997 unsigned NumBytes = API.getBitWidth() / 8; 1998 unsigned TrailingBytes = NumBytes % sizeof(uint64_t); 1999 const uint64_t *p = API.getRawData(); 2000 2001 // PPC's long double has odd notions of endianness compared to how LLVM 2002 // handles it: p[0] goes first for *big* endian on PPC. 2003 if (AP.TM.getDataLayout()->isBigEndian() && 2004 !CFP->getType()->isPPC_FP128Ty()) { 2005 int Chunk = API.getNumWords() - 1; 2006 2007 if (TrailingBytes) 2008 AP.OutStreamer.EmitIntValue(p[Chunk--], TrailingBytes); 2009 2010 for (; Chunk >= 0; --Chunk) 2011 AP.OutStreamer.EmitIntValue(p[Chunk], sizeof(uint64_t)); 2012 } else { 2013 unsigned Chunk; 2014 for (Chunk = 0; Chunk < NumBytes / sizeof(uint64_t); ++Chunk) 2015 AP.OutStreamer.EmitIntValue(p[Chunk], sizeof(uint64_t)); 2016 2017 if (TrailingBytes) 2018 AP.OutStreamer.EmitIntValue(p[Chunk], TrailingBytes); 2019 } 2020 2021 // Emit the tail padding for the long double. 2022 const DataLayout &DL = *AP.TM.getDataLayout(); 2023 AP.OutStreamer.EmitZeros(DL.getTypeAllocSize(CFP->getType()) - 2024 DL.getTypeStoreSize(CFP->getType())); 2025 } 2026 2027 static void emitGlobalConstantLargeInt(const ConstantInt *CI, AsmPrinter &AP) { 2028 const DataLayout *DL = AP.TM.getDataLayout(); 2029 unsigned BitWidth = CI->getBitWidth(); 2030 2031 // Copy the value as we may massage the layout for constants whose bit width 2032 // is not a multiple of 64-bits. 2033 APInt Realigned(CI->getValue()); 2034 uint64_t ExtraBits = 0; 2035 unsigned ExtraBitsSize = BitWidth & 63; 2036 2037 if (ExtraBitsSize) { 2038 // The bit width of the data is not a multiple of 64-bits. 2039 // The extra bits are expected to be at the end of the chunk of the memory. 2040 // Little endian: 2041 // * Nothing to be done, just record the extra bits to emit. 2042 // Big endian: 2043 // * Record the extra bits to emit. 2044 // * Realign the raw data to emit the chunks of 64-bits. 2045 if (DL->isBigEndian()) { 2046 // Basically the structure of the raw data is a chunk of 64-bits cells: 2047 // 0 1 BitWidth / 64 2048 // [chunk1][chunk2] ... [chunkN]. 2049 // The most significant chunk is chunkN and it should be emitted first. 2050 // However, due to the alignment issue chunkN contains useless bits. 2051 // Realign the chunks so that they contain only useless information: 2052 // ExtraBits 0 1 (BitWidth / 64) - 1 2053 // chu[nk1 chu][nk2 chu] ... [nkN-1 chunkN] 2054 ExtraBits = Realigned.getRawData()[0] & 2055 (((uint64_t)-1) >> (64 - ExtraBitsSize)); 2056 Realigned = Realigned.lshr(ExtraBitsSize); 2057 } else 2058 ExtraBits = Realigned.getRawData()[BitWidth / 64]; 2059 } 2060 2061 // We don't expect assemblers to support integer data directives 2062 // for more than 64 bits, so we emit the data in at most 64-bit 2063 // quantities at a time. 2064 const uint64_t *RawData = Realigned.getRawData(); 2065 for (unsigned i = 0, e = BitWidth / 64; i != e; ++i) { 2066 uint64_t Val = DL->isBigEndian() ? RawData[e - i - 1] : RawData[i]; 2067 AP.OutStreamer.EmitIntValue(Val, 8); 2068 } 2069 2070 if (ExtraBitsSize) { 2071 // Emit the extra bits after the 64-bits chunks. 2072 2073 // Emit a directive that fills the expected size. 2074 uint64_t Size = AP.TM.getDataLayout()->getTypeAllocSize( 2075 CI->getType()); 2076 Size -= (BitWidth / 64) * 8; 2077 assert(Size && Size * 8 >= ExtraBitsSize && 2078 (ExtraBits & (((uint64_t)-1) >> (64 - ExtraBitsSize))) 2079 == ExtraBits && "Directive too small for extra bits."); 2080 AP.OutStreamer.EmitIntValue(ExtraBits, Size); 2081 } 2082 } 2083 2084 /// \brief Transform a not absolute MCExpr containing a reference to a GOT 2085 /// equivalent global, by a target specific GOT pc relative access to the 2086 /// final symbol. 2087 static void handleIndirectSymViaGOTPCRel(AsmPrinter &AP, const MCExpr **ME, 2088 const Constant *BaseCst, 2089 uint64_t Offset) { 2090 // The global @foo below illustrates a global that uses a got equivalent. 2091 // 2092 // @bar = global i32 42 2093 // @gotequiv = private unnamed_addr constant i32* @bar 2094 // @foo = i32 trunc (i64 sub (i64 ptrtoint (i32** @gotequiv to i64), 2095 // i64 ptrtoint (i32* @foo to i64)) 2096 // to i32) 2097 // 2098 // The cstexpr in @foo is converted into the MCExpr `ME`, where we actually 2099 // check whether @foo is suitable to use a GOTPCREL. `ME` is usually in the 2100 // form: 2101 // 2102 // foo = cstexpr, where 2103 // cstexpr := <gotequiv> - "." + <cst> 2104 // cstexpr := <gotequiv> - (<foo> - <offset from @foo base>) + <cst> 2105 // 2106 // After canonicalization by EvaluateAsRelocatable `ME` turns into: 2107 // 2108 // cstexpr := <gotequiv> - <foo> + gotpcrelcst, where 2109 // gotpcrelcst := <offset from @foo base> + <cst> 2110 // 2111 MCValue MV; 2112 if (!(*ME)->EvaluateAsRelocatable(MV, nullptr, nullptr) || MV.isAbsolute()) 2113 return; 2114 2115 const MCSymbol *GOTEquivSym = &MV.getSymA()->getSymbol(); 2116 if (!AP.GlobalGOTEquivs.count(GOTEquivSym)) 2117 return; 2118 2119 const GlobalValue *BaseGV = dyn_cast<GlobalValue>(BaseCst); 2120 if (!BaseGV) 2121 return; 2122 2123 const MCSymbol *BaseSym = AP.getSymbol(BaseGV); 2124 if (BaseSym != &MV.getSymB()->getSymbol()) 2125 return; 2126 2127 // Make sure to match: 2128 // 2129 // gotpcrelcst := <offset from @foo base> + <cst> 2130 // 2131 // If gotpcrelcst is positive it means that we can safely fold the pc rel 2132 // displacement into the GOTPCREL. We can also can have an extra offset <cst> 2133 // if the target knows how to encode it. 2134 // 2135 int64_t GOTPCRelCst = Offset + MV.getConstant(); 2136 if (GOTPCRelCst < 0) 2137 return; 2138 if (!AP.getObjFileLowering().supportGOTPCRelWithOffset() && GOTPCRelCst != 0) 2139 return; 2140 2141 // Emit the GOT PC relative to replace the got equivalent global, i.e.: 2142 // 2143 // bar: 2144 // .long 42 2145 // gotequiv: 2146 // .quad bar 2147 // foo: 2148 // .long gotequiv - "." + <cst> 2149 // 2150 // is replaced by the target specific equivalent to: 2151 // 2152 // bar: 2153 // .long 42 2154 // foo: 2155 // .long bar@GOTPCREL+<gotpcrelcst> 2156 // 2157 AsmPrinter::GOTEquivUsePair Result = AP.GlobalGOTEquivs[GOTEquivSym]; 2158 const GlobalVariable *GV = Result.first; 2159 int NumUses = (int)Result.second; 2160 const GlobalValue *FinalGV = dyn_cast<GlobalValue>(GV->getOperand(0)); 2161 const MCSymbol *FinalSym = AP.getSymbol(FinalGV); 2162 *ME = AP.getObjFileLowering().getIndirectSymViaGOTPCRel( 2163 FinalSym, MV, Offset, AP.MMI, AP.OutStreamer); 2164 2165 // Update GOT equivalent usage information 2166 --NumUses; 2167 if (NumUses >= 0) 2168 AP.GlobalGOTEquivs[GOTEquivSym] = std::make_pair(GV, NumUses); 2169 } 2170 2171 static void emitGlobalConstantImpl(const Constant *CV, AsmPrinter &AP, 2172 const Constant *BaseCV, uint64_t Offset) { 2173 const DataLayout *DL = AP.TM.getDataLayout(); 2174 uint64_t Size = DL->getTypeAllocSize(CV->getType()); 2175 2176 // Globals with sub-elements such as combinations of arrays and structs 2177 // are handled recursively by emitGlobalConstantImpl. Keep track of the 2178 // constant symbol base and the current position with BaseCV and Offset. 2179 if (!BaseCV && CV->hasOneUse()) 2180 BaseCV = dyn_cast<Constant>(CV->user_back()); 2181 2182 if (isa<ConstantAggregateZero>(CV) || isa<UndefValue>(CV)) 2183 return AP.OutStreamer.EmitZeros(Size); 2184 2185 if (const ConstantInt *CI = dyn_cast<ConstantInt>(CV)) { 2186 switch (Size) { 2187 case 1: 2188 case 2: 2189 case 4: 2190 case 8: 2191 if (AP.isVerbose()) 2192 AP.OutStreamer.GetCommentOS() << format("0x%" PRIx64 "\n", 2193 CI->getZExtValue()); 2194 AP.OutStreamer.EmitIntValue(CI->getZExtValue(), Size); 2195 return; 2196 default: 2197 emitGlobalConstantLargeInt(CI, AP); 2198 return; 2199 } 2200 } 2201 2202 if (const ConstantFP *CFP = dyn_cast<ConstantFP>(CV)) 2203 return emitGlobalConstantFP(CFP, AP); 2204 2205 if (isa<ConstantPointerNull>(CV)) { 2206 AP.OutStreamer.EmitIntValue(0, Size); 2207 return; 2208 } 2209 2210 if (const ConstantDataSequential *CDS = dyn_cast<ConstantDataSequential>(CV)) 2211 return emitGlobalConstantDataSequential(CDS, AP); 2212 2213 if (const ConstantArray *CVA = dyn_cast<ConstantArray>(CV)) 2214 return emitGlobalConstantArray(CVA, AP, BaseCV, Offset); 2215 2216 if (const ConstantStruct *CVS = dyn_cast<ConstantStruct>(CV)) 2217 return emitGlobalConstantStruct(CVS, AP, BaseCV, Offset); 2218 2219 if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(CV)) { 2220 // Look through bitcasts, which might not be able to be MCExpr'ized (e.g. of 2221 // vectors). 2222 if (CE->getOpcode() == Instruction::BitCast) 2223 return emitGlobalConstantImpl(CE->getOperand(0), AP); 2224 2225 if (Size > 8) { 2226 // If the constant expression's size is greater than 64-bits, then we have 2227 // to emit the value in chunks. Try to constant fold the value and emit it 2228 // that way. 2229 Constant *New = ConstantFoldConstantExpression(CE, *DL); 2230 if (New && New != CE) 2231 return emitGlobalConstantImpl(New, AP); 2232 } 2233 } 2234 2235 if (const ConstantVector *V = dyn_cast<ConstantVector>(CV)) 2236 return emitGlobalConstantVector(V, AP); 2237 2238 // Otherwise, it must be a ConstantExpr. Lower it to an MCExpr, then emit it 2239 // thread the streamer with EmitValue. 2240 const MCExpr *ME = AP.lowerConstant(CV); 2241 2242 // Since lowerConstant already folded and got rid of all IR pointer and 2243 // integer casts, detect GOT equivalent accesses by looking into the MCExpr 2244 // directly. 2245 if (AP.getObjFileLowering().supportIndirectSymViaGOTPCRel()) 2246 handleIndirectSymViaGOTPCRel(AP, &ME, BaseCV, Offset); 2247 2248 AP.OutStreamer.EmitValue(ME, Size); 2249 } 2250 2251 /// EmitGlobalConstant - Print a general LLVM constant to the .s file. 2252 void AsmPrinter::EmitGlobalConstant(const Constant *CV) { 2253 uint64_t Size = 2254 TM.getDataLayout()->getTypeAllocSize(CV->getType()); 2255 if (Size) 2256 emitGlobalConstantImpl(CV, *this); 2257 else if (MAI->hasSubsectionsViaSymbols()) { 2258 // If the global has zero size, emit a single byte so that two labels don't 2259 // look like they are at the same location. 2260 OutStreamer.EmitIntValue(0, 1); 2261 } 2262 } 2263 2264 void AsmPrinter::EmitMachineConstantPoolValue(MachineConstantPoolValue *MCPV) { 2265 // Target doesn't support this yet! 2266 llvm_unreachable("Target does not support EmitMachineConstantPoolValue"); 2267 } 2268 2269 void AsmPrinter::printOffset(int64_t Offset, raw_ostream &OS) const { 2270 if (Offset > 0) 2271 OS << '+' << Offset; 2272 else if (Offset < 0) 2273 OS << Offset; 2274 } 2275 2276 //===----------------------------------------------------------------------===// 2277 // Symbol Lowering Routines. 2278 //===----------------------------------------------------------------------===// 2279 2280 MCSymbol *AsmPrinter::createTempSymbol(const Twine &Name) const { 2281 return OutContext.createTempSymbol(Name, true); 2282 } 2283 2284 MCSymbol *AsmPrinter::GetBlockAddressSymbol(const BlockAddress *BA) const { 2285 return MMI->getAddrLabelSymbol(BA->getBasicBlock()); 2286 } 2287 2288 MCSymbol *AsmPrinter::GetBlockAddressSymbol(const BasicBlock *BB) const { 2289 return MMI->getAddrLabelSymbol(BB); 2290 } 2291 2292 /// GetCPISymbol - Return the symbol for the specified constant pool entry. 2293 MCSymbol *AsmPrinter::GetCPISymbol(unsigned CPID) const { 2294 const DataLayout *DL = TM.getDataLayout(); 2295 return OutContext.GetOrCreateSymbol 2296 (Twine(DL->getPrivateGlobalPrefix()) + "CPI" + Twine(getFunctionNumber()) 2297 + "_" + Twine(CPID)); 2298 } 2299 2300 /// GetJTISymbol - Return the symbol for the specified jump table entry. 2301 MCSymbol *AsmPrinter::GetJTISymbol(unsigned JTID, bool isLinkerPrivate) const { 2302 return MF->getJTISymbol(JTID, OutContext, isLinkerPrivate); 2303 } 2304 2305 /// GetJTSetSymbol - Return the symbol for the specified jump table .set 2306 /// FIXME: privatize to AsmPrinter. 2307 MCSymbol *AsmPrinter::GetJTSetSymbol(unsigned UID, unsigned MBBID) const { 2308 const DataLayout *DL = TM.getDataLayout(); 2309 return OutContext.GetOrCreateSymbol 2310 (Twine(DL->getPrivateGlobalPrefix()) + Twine(getFunctionNumber()) + "_" + 2311 Twine(UID) + "_set_" + Twine(MBBID)); 2312 } 2313 2314 MCSymbol *AsmPrinter::getSymbolWithGlobalValueBase(const GlobalValue *GV, 2315 StringRef Suffix) const { 2316 return getObjFileLowering().getSymbolWithGlobalValueBase(GV, Suffix, *Mang, 2317 TM); 2318 } 2319 2320 /// GetExternalSymbolSymbol - Return the MCSymbol for the specified 2321 /// ExternalSymbol. 2322 MCSymbol *AsmPrinter::GetExternalSymbolSymbol(StringRef Sym) const { 2323 SmallString<60> NameStr; 2324 Mang->getNameWithPrefix(NameStr, Sym); 2325 return OutContext.GetOrCreateSymbol(NameStr); 2326 } 2327 2328 2329 2330 /// PrintParentLoopComment - Print comments about parent loops of this one. 2331 static void PrintParentLoopComment(raw_ostream &OS, const MachineLoop *Loop, 2332 unsigned FunctionNumber) { 2333 if (!Loop) return; 2334 PrintParentLoopComment(OS, Loop->getParentLoop(), FunctionNumber); 2335 OS.indent(Loop->getLoopDepth()*2) 2336 << "Parent Loop BB" << FunctionNumber << "_" 2337 << Loop->getHeader()->getNumber() 2338 << " Depth=" << Loop->getLoopDepth() << '\n'; 2339 } 2340 2341 2342 /// PrintChildLoopComment - Print comments about child loops within 2343 /// the loop for this basic block, with nesting. 2344 static void PrintChildLoopComment(raw_ostream &OS, const MachineLoop *Loop, 2345 unsigned FunctionNumber) { 2346 // Add child loop information 2347 for (const MachineLoop *CL : *Loop) { 2348 OS.indent(CL->getLoopDepth()*2) 2349 << "Child Loop BB" << FunctionNumber << "_" 2350 << CL->getHeader()->getNumber() << " Depth " << CL->getLoopDepth() 2351 << '\n'; 2352 PrintChildLoopComment(OS, CL, FunctionNumber); 2353 } 2354 } 2355 2356 /// emitBasicBlockLoopComments - Pretty-print comments for basic blocks. 2357 static void emitBasicBlockLoopComments(const MachineBasicBlock &MBB, 2358 const MachineLoopInfo *LI, 2359 const AsmPrinter &AP) { 2360 // Add loop depth information 2361 const MachineLoop *Loop = LI->getLoopFor(&MBB); 2362 if (!Loop) return; 2363 2364 MachineBasicBlock *Header = Loop->getHeader(); 2365 assert(Header && "No header for loop"); 2366 2367 // If this block is not a loop header, just print out what is the loop header 2368 // and return. 2369 if (Header != &MBB) { 2370 AP.OutStreamer.AddComment(" in Loop: Header=BB" + 2371 Twine(AP.getFunctionNumber())+"_" + 2372 Twine(Loop->getHeader()->getNumber())+ 2373 " Depth="+Twine(Loop->getLoopDepth())); 2374 return; 2375 } 2376 2377 // Otherwise, it is a loop header. Print out information about child and 2378 // parent loops. 2379 raw_ostream &OS = AP.OutStreamer.GetCommentOS(); 2380 2381 PrintParentLoopComment(OS, Loop->getParentLoop(), AP.getFunctionNumber()); 2382 2383 OS << "=>"; 2384 OS.indent(Loop->getLoopDepth()*2-2); 2385 2386 OS << "This "; 2387 if (Loop->empty()) 2388 OS << "Inner "; 2389 OS << "Loop Header: Depth=" + Twine(Loop->getLoopDepth()) << '\n'; 2390 2391 PrintChildLoopComment(OS, Loop, AP.getFunctionNumber()); 2392 } 2393 2394 2395 /// EmitBasicBlockStart - This method prints the label for the specified 2396 /// MachineBasicBlock, an alignment (if present) and a comment describing 2397 /// it if appropriate. 2398 void AsmPrinter::EmitBasicBlockStart(const MachineBasicBlock &MBB) const { 2399 // Emit an alignment directive for this block, if needed. 2400 if (unsigned Align = MBB.getAlignment()) 2401 EmitAlignment(Align); 2402 2403 // If the block has its address taken, emit any labels that were used to 2404 // reference the block. It is possible that there is more than one label 2405 // here, because multiple LLVM BB's may have been RAUW'd to this block after 2406 // the references were generated. 2407 if (MBB.hasAddressTaken()) { 2408 const BasicBlock *BB = MBB.getBasicBlock(); 2409 if (isVerbose()) 2410 OutStreamer.AddComment("Block address taken"); 2411 2412 std::vector<MCSymbol*> Symbols = MMI->getAddrLabelSymbolToEmit(BB); 2413 for (auto *Sym : Symbols) 2414 OutStreamer.EmitLabel(Sym); 2415 } 2416 2417 // Print some verbose block comments. 2418 if (isVerbose()) { 2419 if (const BasicBlock *BB = MBB.getBasicBlock()) 2420 if (BB->hasName()) 2421 OutStreamer.AddComment("%" + BB->getName()); 2422 emitBasicBlockLoopComments(MBB, LI, *this); 2423 } 2424 2425 // Print the main label for the block. 2426 if (MBB.pred_empty() || isBlockOnlyReachableByFallthrough(&MBB)) { 2427 if (isVerbose()) { 2428 // NOTE: Want this comment at start of line, don't emit with AddComment. 2429 OutStreamer.emitRawComment(" BB#" + Twine(MBB.getNumber()) + ":", false); 2430 } 2431 } else { 2432 OutStreamer.EmitLabel(MBB.getSymbol()); 2433 } 2434 } 2435 2436 void AsmPrinter::EmitVisibility(MCSymbol *Sym, unsigned Visibility, 2437 bool IsDefinition) const { 2438 MCSymbolAttr Attr = MCSA_Invalid; 2439 2440 switch (Visibility) { 2441 default: break; 2442 case GlobalValue::HiddenVisibility: 2443 if (IsDefinition) 2444 Attr = MAI->getHiddenVisibilityAttr(); 2445 else 2446 Attr = MAI->getHiddenDeclarationVisibilityAttr(); 2447 break; 2448 case GlobalValue::ProtectedVisibility: 2449 Attr = MAI->getProtectedVisibilityAttr(); 2450 break; 2451 } 2452 2453 if (Attr != MCSA_Invalid) 2454 OutStreamer.EmitSymbolAttribute(Sym, Attr); 2455 } 2456 2457 /// isBlockOnlyReachableByFallthough - Return true if the basic block has 2458 /// exactly one predecessor and the control transfer mechanism between 2459 /// the predecessor and this block is a fall-through. 2460 bool AsmPrinter:: 2461 isBlockOnlyReachableByFallthrough(const MachineBasicBlock *MBB) const { 2462 // If this is a landing pad, it isn't a fall through. If it has no preds, 2463 // then nothing falls through to it. 2464 if (MBB->isLandingPad() || MBB->pred_empty()) 2465 return false; 2466 2467 // If there isn't exactly one predecessor, it can't be a fall through. 2468 if (MBB->pred_size() > 1) 2469 return false; 2470 2471 // The predecessor has to be immediately before this block. 2472 MachineBasicBlock *Pred = *MBB->pred_begin(); 2473 if (!Pred->isLayoutSuccessor(MBB)) 2474 return false; 2475 2476 // If the block is completely empty, then it definitely does fall through. 2477 if (Pred->empty()) 2478 return true; 2479 2480 // Check the terminators in the previous blocks 2481 for (const auto &MI : Pred->terminators()) { 2482 // If it is not a simple branch, we are in a table somewhere. 2483 if (!MI.isBranch() || MI.isIndirectBranch()) 2484 return false; 2485 2486 // If we are the operands of one of the branches, this is not a fall 2487 // through. Note that targets with delay slots will usually bundle 2488 // terminators with the delay slot instruction. 2489 for (ConstMIBundleOperands OP(&MI); OP.isValid(); ++OP) { 2490 if (OP->isJTI()) 2491 return false; 2492 if (OP->isMBB() && OP->getMBB() == MBB) 2493 return false; 2494 } 2495 } 2496 2497 return true; 2498 } 2499 2500 2501 2502 GCMetadataPrinter *AsmPrinter::GetOrCreateGCPrinter(GCStrategy &S) { 2503 if (!S.usesMetadata()) 2504 return nullptr; 2505 2506 assert(!S.useStatepoints() && "statepoints do not currently support custom" 2507 " stackmap formats, please see the documentation for a description of" 2508 " the default format. If you really need a custom serialized format," 2509 " please file a bug"); 2510 2511 gcp_map_type &GCMap = getGCMap(GCMetadataPrinters); 2512 gcp_map_type::iterator GCPI = GCMap.find(&S); 2513 if (GCPI != GCMap.end()) 2514 return GCPI->second.get(); 2515 2516 const char *Name = S.getName().c_str(); 2517 2518 for (GCMetadataPrinterRegistry::iterator 2519 I = GCMetadataPrinterRegistry::begin(), 2520 E = GCMetadataPrinterRegistry::end(); I != E; ++I) 2521 if (strcmp(Name, I->getName()) == 0) { 2522 std::unique_ptr<GCMetadataPrinter> GMP = I->instantiate(); 2523 GMP->S = &S; 2524 auto IterBool = GCMap.insert(std::make_pair(&S, std::move(GMP))); 2525 return IterBool.first->second.get(); 2526 } 2527 2528 report_fatal_error("no GCMetadataPrinter registered for GC: " + Twine(Name)); 2529 } 2530 2531 /// Pin vtable to this file. 2532 AsmPrinterHandler::~AsmPrinterHandler() {} 2533 2534 void AsmPrinterHandler::markFunctionEnd() {} 2535