AsmPrinter.cpp revision 266715
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#define DEBUG_TYPE "asm-printer" 15#include "llvm/CodeGen/AsmPrinter.h" 16#include "DwarfDebug.h" 17#include "DwarfException.h" 18#include "llvm/ADT/SmallString.h" 19#include "llvm/ADT/Statistic.h" 20#include "llvm/Analysis/ConstantFolding.h" 21#include "llvm/Assembly/Writer.h" 22#include "llvm/CodeGen/GCMetadataPrinter.h" 23#include "llvm/CodeGen/MachineConstantPool.h" 24#include "llvm/CodeGen/MachineFrameInfo.h" 25#include "llvm/CodeGen/MachineFunction.h" 26#include "llvm/CodeGen/MachineInstrBundle.h" 27#include "llvm/CodeGen/MachineJumpTableInfo.h" 28#include "llvm/CodeGen/MachineLoopInfo.h" 29#include "llvm/CodeGen/MachineModuleInfo.h" 30#include "llvm/DebugInfo.h" 31#include "llvm/IR/DataLayout.h" 32#include "llvm/IR/Module.h" 33#include "llvm/IR/Operator.h" 34#include "llvm/MC/MCAsmInfo.h" 35#include "llvm/MC/MCContext.h" 36#include "llvm/MC/MCExpr.h" 37#include "llvm/MC/MCInst.h" 38#include "llvm/MC/MCSection.h" 39#include "llvm/MC/MCStreamer.h" 40#include "llvm/MC/MCSymbol.h" 41#include "llvm/Support/ErrorHandling.h" 42#include "llvm/Support/Format.h" 43#include "llvm/Support/MathExtras.h" 44#include "llvm/Support/Timer.h" 45#include "llvm/Target/Mangler.h" 46#include "llvm/Target/TargetFrameLowering.h" 47#include "llvm/Target/TargetInstrInfo.h" 48#include "llvm/Target/TargetLowering.h" 49#include "llvm/Target/TargetLoweringObjectFile.h" 50#include "llvm/Target/TargetOptions.h" 51#include "llvm/Target/TargetRegisterInfo.h" 52#include "llvm/Transforms/Utils/GlobalStatus.h" 53using namespace llvm; 54 55static const char *const DWARFGroupName = "DWARF Emission"; 56static const char *const DbgTimerName = "DWARF Debug Writer"; 57static const char *const EHTimerName = "DWARF Exception Writer"; 58 59STATISTIC(EmittedInsts, "Number of machine instrs printed"); 60 61char AsmPrinter::ID = 0; 62 63typedef DenseMap<GCStrategy*,GCMetadataPrinter*> gcp_map_type; 64static gcp_map_type &getGCMap(void *&P) { 65 if (P == 0) 66 P = new gcp_map_type(); 67 return *(gcp_map_type*)P; 68} 69 70 71/// getGVAlignmentLog2 - Return the alignment to use for the specified global 72/// value in log2 form. This rounds up to the preferred alignment if possible 73/// and legal. 74static unsigned getGVAlignmentLog2(const GlobalValue *GV, const DataLayout &TD, 75 unsigned InBits = 0) { 76 unsigned NumBits = 0; 77 if (const GlobalVariable *GVar = dyn_cast<GlobalVariable>(GV)) 78 NumBits = TD.getPreferredAlignmentLog(GVar); 79 80 // If InBits is specified, round it to it. 81 if (InBits > NumBits) 82 NumBits = InBits; 83 84 // If the GV has a specified alignment, take it into account. 85 if (GV->getAlignment() == 0) 86 return NumBits; 87 88 unsigned GVAlign = Log2_32(GV->getAlignment()); 89 90 // If the GVAlign is larger than NumBits, or if we are required to obey 91 // NumBits because the GV has an assigned section, obey it. 92 if (GVAlign > NumBits || GV->hasSection()) 93 NumBits = GVAlign; 94 return NumBits; 95} 96 97AsmPrinter::AsmPrinter(TargetMachine &tm, MCStreamer &Streamer) 98 : MachineFunctionPass(ID), 99 TM(tm), MAI(tm.getMCAsmInfo()), MII(tm.getInstrInfo()), 100 OutContext(Streamer.getContext()), 101 OutStreamer(Streamer), 102 LastMI(0), LastFn(0), Counter(~0U), SetCounter(0) { 103 DD = 0; DE = 0; MMI = 0; LI = 0; MF = 0; 104 CurrentFnSym = CurrentFnSymForSize = 0; 105 GCMetadataPrinters = 0; 106 VerboseAsm = Streamer.isVerboseAsm(); 107} 108 109AsmPrinter::~AsmPrinter() { 110 assert(DD == 0 && DE == 0 && "Debug/EH info didn't get finalized"); 111 112 if (GCMetadataPrinters != 0) { 113 gcp_map_type &GCMap = getGCMap(GCMetadataPrinters); 114 115 for (gcp_map_type::iterator I = GCMap.begin(), E = GCMap.end(); I != E; ++I) 116 delete I->second; 117 delete &GCMap; 118 GCMetadataPrinters = 0; 119 } 120 121 delete &OutStreamer; 122} 123 124/// getFunctionNumber - Return a unique ID for the current function. 125/// 126unsigned AsmPrinter::getFunctionNumber() const { 127 return MF->getFunctionNumber(); 128} 129 130const TargetLoweringObjectFile &AsmPrinter::getObjFileLowering() const { 131 return TM.getTargetLowering()->getObjFileLowering(); 132} 133 134/// getDataLayout - Return information about data layout. 135const DataLayout &AsmPrinter::getDataLayout() const { 136 return *TM.getDataLayout(); 137} 138 139StringRef AsmPrinter::getTargetTriple() const { 140 return TM.getTargetTriple(); 141} 142 143/// getCurrentSection() - Return the current section we are emitting to. 144const MCSection *AsmPrinter::getCurrentSection() const { 145 return OutStreamer.getCurrentSection().first; 146} 147 148 149 150void AsmPrinter::getAnalysisUsage(AnalysisUsage &AU) const { 151 AU.setPreservesAll(); 152 MachineFunctionPass::getAnalysisUsage(AU); 153 AU.addRequired<MachineModuleInfo>(); 154 AU.addRequired<GCModuleInfo>(); 155 if (isVerbose()) 156 AU.addRequired<MachineLoopInfo>(); 157} 158 159bool AsmPrinter::doInitialization(Module &M) { 160 MMI = getAnalysisIfAvailable<MachineModuleInfo>(); 161 MMI->AnalyzeModule(M); 162 163 // Initialize TargetLoweringObjectFile. 164 const_cast<TargetLoweringObjectFile&>(getObjFileLowering()) 165 .Initialize(OutContext, TM); 166 167 OutStreamer.InitStreamer(); 168 169 Mang = new Mangler(&TM); 170 171 // Allow the target to emit any magic that it wants at the start of the file. 172 EmitStartOfAsmFile(M); 173 174 // Very minimal debug info. It is ignored if we emit actual debug info. If we 175 // don't, this at least helps the user find where a global came from. 176 if (MAI->hasSingleParameterDotFile()) { 177 // .file "foo.c" 178 OutStreamer.EmitFileDirective(M.getModuleIdentifier()); 179 } 180 181 GCModuleInfo *MI = getAnalysisIfAvailable<GCModuleInfo>(); 182 assert(MI && "AsmPrinter didn't require GCModuleInfo?"); 183 for (GCModuleInfo::iterator I = MI->begin(), E = MI->end(); I != E; ++I) 184 if (GCMetadataPrinter *MP = GetOrCreateGCPrinter(*I)) 185 MP->beginAssembly(*this); 186 187 // Emit module-level inline asm if it exists. 188 if (!M.getModuleInlineAsm().empty()) { 189 OutStreamer.AddComment("Start of file scope inline assembly"); 190 OutStreamer.AddBlankLine(); 191 EmitInlineAsm(M.getModuleInlineAsm()+"\n"); 192 OutStreamer.AddComment("End of file scope inline assembly"); 193 OutStreamer.AddBlankLine(); 194 } 195 196 if (MAI->doesSupportDebugInformation()) 197 DD = new DwarfDebug(this, &M); 198 199 switch (MAI->getExceptionHandlingType()) { 200 case ExceptionHandling::None: 201 return false; 202 case ExceptionHandling::SjLj: 203 case ExceptionHandling::DwarfCFI: 204 DE = new DwarfCFIException(this); 205 return false; 206 case ExceptionHandling::ARM: 207 DE = new ARMException(this); 208 return false; 209 case ExceptionHandling::Win64: 210 DE = new Win64Exception(this); 211 return false; 212 } 213 214 llvm_unreachable("Unknown exception type."); 215} 216 217void AsmPrinter::EmitLinkage(const GlobalValue *GV, MCSymbol *GVSym) const { 218 GlobalValue::LinkageTypes Linkage = GV->getLinkage(); 219 switch (Linkage) { 220 case GlobalValue::CommonLinkage: 221 case GlobalValue::LinkOnceAnyLinkage: 222 case GlobalValue::LinkOnceODRLinkage: 223 case GlobalValue::WeakAnyLinkage: 224 case GlobalValue::WeakODRLinkage: 225 case GlobalValue::LinkerPrivateWeakLinkage: 226 if (MAI->hasWeakDefDirective()) { 227 // .globl _foo 228 OutStreamer.EmitSymbolAttribute(GVSym, MCSA_Global); 229 230 bool CanBeHidden = false; 231 232 if (Linkage == GlobalValue::LinkOnceODRLinkage && 233 MAI->hasWeakDefCanBeHiddenDirective()) { 234 if (GV->hasUnnamedAddr()) { 235 CanBeHidden = true; 236 } else { 237 GlobalStatus GS; 238 if (!GlobalStatus::analyzeGlobal(GV, GS) && !GS.IsCompared) 239 CanBeHidden = true; 240 } 241 } 242 243 if (!CanBeHidden) 244 // .weak_definition _foo 245 OutStreamer.EmitSymbolAttribute(GVSym, MCSA_WeakDefinition); 246 else 247 OutStreamer.EmitSymbolAttribute(GVSym, MCSA_WeakDefAutoPrivate); 248 } else if (MAI->hasLinkOnceDirective()) { 249 // .globl _foo 250 OutStreamer.EmitSymbolAttribute(GVSym, MCSA_Global); 251 //NOTE: linkonce is handled by the section the symbol was assigned to. 252 } else { 253 // .weak _foo 254 OutStreamer.EmitSymbolAttribute(GVSym, MCSA_Weak); 255 } 256 return; 257 case GlobalValue::DLLExportLinkage: 258 case GlobalValue::AppendingLinkage: 259 // FIXME: appending linkage variables should go into a section of 260 // their name or something. For now, just emit them as external. 261 case GlobalValue::ExternalLinkage: 262 // If external or appending, declare as a global symbol. 263 // .globl _foo 264 OutStreamer.EmitSymbolAttribute(GVSym, MCSA_Global); 265 return; 266 case GlobalValue::PrivateLinkage: 267 case GlobalValue::InternalLinkage: 268 case GlobalValue::LinkerPrivateLinkage: 269 return; 270 case GlobalValue::AvailableExternallyLinkage: 271 llvm_unreachable("Should never emit this"); 272 case GlobalValue::DLLImportLinkage: 273 case GlobalValue::ExternalWeakLinkage: 274 llvm_unreachable("Don't know how to emit these"); 275 } 276 llvm_unreachable("Unknown linkage type!"); 277} 278 279MCSymbol *AsmPrinter::getSymbol(const GlobalValue *GV) const { 280 return getObjFileLowering().getSymbol(*Mang, GV); 281} 282 283/// EmitGlobalVariable - Emit the specified global variable to the .s file. 284void AsmPrinter::EmitGlobalVariable(const GlobalVariable *GV) { 285 if (GV->hasInitializer()) { 286 // Check to see if this is a special global used by LLVM, if so, emit it. 287 if (EmitSpecialLLVMGlobal(GV)) 288 return; 289 290 if (isVerbose()) { 291 WriteAsOperand(OutStreamer.GetCommentOS(), GV, 292 /*PrintType=*/false, GV->getParent()); 293 OutStreamer.GetCommentOS() << '\n'; 294 } 295 } 296 297 MCSymbol *GVSym = getSymbol(GV); 298 EmitVisibility(GVSym, GV->getVisibility(), !GV->isDeclaration()); 299 300 if (!GV->hasInitializer()) // External globals require no extra code. 301 return; 302 303 if (MAI->hasDotTypeDotSizeDirective()) 304 OutStreamer.EmitSymbolAttribute(GVSym, MCSA_ELF_TypeObject); 305 306 SectionKind GVKind = TargetLoweringObjectFile::getKindForGlobal(GV, TM); 307 308 const DataLayout *DL = TM.getDataLayout(); 309 uint64_t Size = DL->getTypeAllocSize(GV->getType()->getElementType()); 310 311 // If the alignment is specified, we *must* obey it. Overaligning a global 312 // with a specified alignment is a prompt way to break globals emitted to 313 // sections and expected to be contiguous (e.g. ObjC metadata). 314 unsigned AlignLog = getGVAlignmentLog2(GV, *DL); 315 316 if (DD) 317 DD->setSymbolSize(GVSym, Size); 318 319 // Handle common and BSS local symbols (.lcomm). 320 if (GVKind.isCommon() || GVKind.isBSSLocal()) { 321 if (Size == 0) Size = 1; // .comm Foo, 0 is undefined, avoid it. 322 unsigned Align = 1 << AlignLog; 323 324 // Handle common symbols. 325 if (GVKind.isCommon()) { 326 if (!getObjFileLowering().getCommDirectiveSupportsAlignment()) 327 Align = 0; 328 329 // .comm _foo, 42, 4 330 OutStreamer.EmitCommonSymbol(GVSym, Size, Align); 331 return; 332 } 333 334 // Handle local BSS symbols. 335 if (MAI->hasMachoZeroFillDirective()) { 336 const MCSection *TheSection = 337 getObjFileLowering().SectionForGlobal(GV, GVKind, Mang, TM); 338 // .zerofill __DATA, __bss, _foo, 400, 5 339 OutStreamer.EmitZerofill(TheSection, GVSym, Size, Align); 340 return; 341 } 342 343 // Use .lcomm only if it supports user-specified alignment. 344 // Otherwise, while it would still be correct to use .lcomm in some 345 // cases (e.g. when Align == 1), the external assembler might enfore 346 // some -unknown- default alignment behavior, which could cause 347 // spurious differences between external and integrated assembler. 348 // Prefer to simply fall back to .local / .comm in this case. 349 if (MAI->getLCOMMDirectiveAlignmentType() != LCOMM::NoAlignment) { 350 // .lcomm _foo, 42 351 OutStreamer.EmitLocalCommonSymbol(GVSym, Size, Align); 352 return; 353 } 354 355 if (!getObjFileLowering().getCommDirectiveSupportsAlignment()) 356 Align = 0; 357 358 // .local _foo 359 OutStreamer.EmitSymbolAttribute(GVSym, MCSA_Local); 360 // .comm _foo, 42, 4 361 OutStreamer.EmitCommonSymbol(GVSym, Size, Align); 362 return; 363 } 364 365 const MCSection *TheSection = 366 getObjFileLowering().SectionForGlobal(GV, GVKind, Mang, TM); 367 368 // Handle the zerofill directive on darwin, which is a special form of BSS 369 // emission. 370 if (GVKind.isBSSExtern() && MAI->hasMachoZeroFillDirective()) { 371 if (Size == 0) Size = 1; // zerofill of 0 bytes is undefined. 372 373 // .globl _foo 374 OutStreamer.EmitSymbolAttribute(GVSym, MCSA_Global); 375 // .zerofill __DATA, __common, _foo, 400, 5 376 OutStreamer.EmitZerofill(TheSection, GVSym, Size, 1 << AlignLog); 377 return; 378 } 379 380 // Handle thread local data for mach-o which requires us to output an 381 // additional structure of data and mangle the original symbol so that we 382 // can reference it later. 383 // 384 // TODO: This should become an "emit thread local global" method on TLOF. 385 // All of this macho specific stuff should be sunk down into TLOFMachO and 386 // stuff like "TLSExtraDataSection" should no longer be part of the parent 387 // TLOF class. This will also make it more obvious that stuff like 388 // MCStreamer::EmitTBSSSymbol is macho specific and only called from macho 389 // specific code. 390 if (GVKind.isThreadLocal() && MAI->hasMachoTBSSDirective()) { 391 // Emit the .tbss symbol 392 MCSymbol *MangSym = 393 OutContext.GetOrCreateSymbol(GVSym->getName() + Twine("$tlv$init")); 394 395 if (GVKind.isThreadBSS()) { 396 TheSection = getObjFileLowering().getTLSBSSSection(); 397 OutStreamer.EmitTBSSSymbol(TheSection, MangSym, Size, 1 << AlignLog); 398 } else if (GVKind.isThreadData()) { 399 OutStreamer.SwitchSection(TheSection); 400 401 EmitAlignment(AlignLog, GV); 402 OutStreamer.EmitLabel(MangSym); 403 404 EmitGlobalConstant(GV->getInitializer()); 405 } 406 407 OutStreamer.AddBlankLine(); 408 409 // Emit the variable struct for the runtime. 410 const MCSection *TLVSect 411 = getObjFileLowering().getTLSExtraDataSection(); 412 413 OutStreamer.SwitchSection(TLVSect); 414 // Emit the linkage here. 415 EmitLinkage(GV, GVSym); 416 OutStreamer.EmitLabel(GVSym); 417 418 // Three pointers in size: 419 // - __tlv_bootstrap - used to make sure support exists 420 // - spare pointer, used when mapped by the runtime 421 // - pointer to mangled symbol above with initializer 422 unsigned PtrSize = DL->getPointerTypeSize(GV->getType()); 423 OutStreamer.EmitSymbolValue(GetExternalSymbolSymbol("_tlv_bootstrap"), 424 PtrSize); 425 OutStreamer.EmitIntValue(0, PtrSize); 426 OutStreamer.EmitSymbolValue(MangSym, PtrSize); 427 428 OutStreamer.AddBlankLine(); 429 return; 430 } 431 432 OutStreamer.SwitchSection(TheSection); 433 434 EmitLinkage(GV, GVSym); 435 EmitAlignment(AlignLog, GV); 436 437 OutStreamer.EmitLabel(GVSym); 438 439 EmitGlobalConstant(GV->getInitializer()); 440 441 if (MAI->hasDotTypeDotSizeDirective()) 442 // .size foo, 42 443 OutStreamer.EmitELFSize(GVSym, MCConstantExpr::Create(Size, OutContext)); 444 445 OutStreamer.AddBlankLine(); 446} 447 448/// EmitFunctionHeader - This method emits the header for the current 449/// function. 450void AsmPrinter::EmitFunctionHeader() { 451 // Print out constants referenced by the function 452 EmitConstantPool(); 453 454 // Print the 'header' of function. 455 const Function *F = MF->getFunction(); 456 457 OutStreamer.SwitchSection(getObjFileLowering().SectionForGlobal(F, Mang, TM)); 458 EmitVisibility(CurrentFnSym, F->getVisibility()); 459 460 EmitLinkage(F, CurrentFnSym); 461 EmitAlignment(MF->getAlignment(), F); 462 463 if (MAI->hasDotTypeDotSizeDirective()) 464 OutStreamer.EmitSymbolAttribute(CurrentFnSym, MCSA_ELF_TypeFunction); 465 466 if (isVerbose()) { 467 WriteAsOperand(OutStreamer.GetCommentOS(), F, 468 /*PrintType=*/false, F->getParent()); 469 OutStreamer.GetCommentOS() << '\n'; 470 } 471 472 // Emit the CurrentFnSym. This is a virtual function to allow targets to 473 // do their wild and crazy things as required. 474 EmitFunctionEntryLabel(); 475 476 // If the function had address-taken blocks that got deleted, then we have 477 // references to the dangling symbols. Emit them at the start of the function 478 // so that we don't get references to undefined symbols. 479 std::vector<MCSymbol*> DeadBlockSyms; 480 MMI->takeDeletedSymbolsForFunction(F, DeadBlockSyms); 481 for (unsigned i = 0, e = DeadBlockSyms.size(); i != e; ++i) { 482 OutStreamer.AddComment("Address taken block that was later removed"); 483 OutStreamer.EmitLabel(DeadBlockSyms[i]); 484 } 485 486 // Emit pre-function debug and/or EH information. 487 if (DE) { 488 NamedRegionTimer T(EHTimerName, DWARFGroupName, TimePassesIsEnabled); 489 DE->BeginFunction(MF); 490 } 491 if (DD) { 492 NamedRegionTimer T(DbgTimerName, DWARFGroupName, TimePassesIsEnabled); 493 DD->beginFunction(MF); 494 } 495 496 // Emit the prefix data. 497 if (F->hasPrefixData()) 498 EmitGlobalConstant(F->getPrefixData()); 499} 500 501/// EmitFunctionEntryLabel - Emit the label that is the entrypoint for the 502/// function. This can be overridden by targets as required to do custom stuff. 503void AsmPrinter::EmitFunctionEntryLabel() { 504 // The function label could have already been emitted if two symbols end up 505 // conflicting due to asm renaming. Detect this and emit an error. 506 if (CurrentFnSym->isUndefined()) 507 return OutStreamer.EmitLabel(CurrentFnSym); 508 509 report_fatal_error("'" + Twine(CurrentFnSym->getName()) + 510 "' label emitted multiple times to assembly file"); 511} 512 513/// emitComments - Pretty-print comments for instructions. 514static void emitComments(const MachineInstr &MI, raw_ostream &CommentOS) { 515 const MachineFunction *MF = MI.getParent()->getParent(); 516 const TargetMachine &TM = MF->getTarget(); 517 518 // Check for spills and reloads 519 int FI; 520 521 const MachineFrameInfo *FrameInfo = MF->getFrameInfo(); 522 523 // We assume a single instruction only has a spill or reload, not 524 // both. 525 const MachineMemOperand *MMO; 526 if (TM.getInstrInfo()->isLoadFromStackSlotPostFE(&MI, FI)) { 527 if (FrameInfo->isSpillSlotObjectIndex(FI)) { 528 MMO = *MI.memoperands_begin(); 529 CommentOS << MMO->getSize() << "-byte Reload\n"; 530 } 531 } else if (TM.getInstrInfo()->hasLoadFromStackSlot(&MI, MMO, FI)) { 532 if (FrameInfo->isSpillSlotObjectIndex(FI)) 533 CommentOS << MMO->getSize() << "-byte Folded Reload\n"; 534 } else if (TM.getInstrInfo()->isStoreToStackSlotPostFE(&MI, FI)) { 535 if (FrameInfo->isSpillSlotObjectIndex(FI)) { 536 MMO = *MI.memoperands_begin(); 537 CommentOS << MMO->getSize() << "-byte Spill\n"; 538 } 539 } else if (TM.getInstrInfo()->hasStoreToStackSlot(&MI, MMO, FI)) { 540 if (FrameInfo->isSpillSlotObjectIndex(FI)) 541 CommentOS << MMO->getSize() << "-byte Folded Spill\n"; 542 } 543 544 // Check for spill-induced copies 545 if (MI.getAsmPrinterFlag(MachineInstr::ReloadReuse)) 546 CommentOS << " Reload Reuse\n"; 547} 548 549/// emitImplicitDef - This method emits the specified machine instruction 550/// that is an implicit def. 551void AsmPrinter::emitImplicitDef(const MachineInstr *MI) const { 552 unsigned RegNo = MI->getOperand(0).getReg(); 553 OutStreamer.AddComment(Twine("implicit-def: ") + 554 TM.getRegisterInfo()->getName(RegNo)); 555 OutStreamer.AddBlankLine(); 556} 557 558static void emitKill(const MachineInstr *MI, AsmPrinter &AP) { 559 std::string Str = "kill:"; 560 for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) { 561 const MachineOperand &Op = MI->getOperand(i); 562 assert(Op.isReg() && "KILL instruction must have only register operands"); 563 Str += ' '; 564 Str += AP.TM.getRegisterInfo()->getName(Op.getReg()); 565 Str += (Op.isDef() ? "<def>" : "<kill>"); 566 } 567 AP.OutStreamer.AddComment(Str); 568 AP.OutStreamer.AddBlankLine(); 569} 570 571/// emitDebugValueComment - This method handles the target-independent form 572/// of DBG_VALUE, returning true if it was able to do so. A false return 573/// means the target will need to handle MI in EmitInstruction. 574static bool emitDebugValueComment(const MachineInstr *MI, AsmPrinter &AP) { 575 // This code handles only the 3-operand target-independent form. 576 if (MI->getNumOperands() != 3) 577 return false; 578 579 SmallString<128> Str; 580 raw_svector_ostream OS(Str); 581 OS << '\t' << AP.MAI->getCommentString() << "DEBUG_VALUE: "; 582 583 // cast away const; DIetc do not take const operands for some reason. 584 DIVariable V(const_cast<MDNode*>(MI->getOperand(2).getMetadata())); 585 if (V.getContext().isSubprogram()) { 586 StringRef Name = DISubprogram(V.getContext()).getDisplayName(); 587 if (!Name.empty()) 588 OS << Name << ":"; 589 } 590 OS << V.getName() << " <- "; 591 592 // The second operand is only an offset if it's an immediate. 593 bool Deref = MI->getOperand(0).isReg() && MI->getOperand(1).isImm(); 594 int64_t Offset = Deref ? MI->getOperand(1).getImm() : 0; 595 596 // Register or immediate value. Register 0 means undef. 597 if (MI->getOperand(0).isFPImm()) { 598 APFloat APF = APFloat(MI->getOperand(0).getFPImm()->getValueAPF()); 599 if (MI->getOperand(0).getFPImm()->getType()->isFloatTy()) { 600 OS << (double)APF.convertToFloat(); 601 } else if (MI->getOperand(0).getFPImm()->getType()->isDoubleTy()) { 602 OS << APF.convertToDouble(); 603 } else { 604 // There is no good way to print long double. Convert a copy to 605 // double. Ah well, it's only a comment. 606 bool ignored; 607 APF.convert(APFloat::IEEEdouble, APFloat::rmNearestTiesToEven, 608 &ignored); 609 OS << "(long double) " << APF.convertToDouble(); 610 } 611 } else if (MI->getOperand(0).isImm()) { 612 OS << MI->getOperand(0).getImm(); 613 } else if (MI->getOperand(0).isCImm()) { 614 MI->getOperand(0).getCImm()->getValue().print(OS, false /*isSigned*/); 615 } else { 616 unsigned Reg; 617 if (MI->getOperand(0).isReg()) { 618 Reg = MI->getOperand(0).getReg(); 619 } else { 620 assert(MI->getOperand(0).isFI() && "Unknown operand type"); 621 const TargetFrameLowering *TFI = AP.TM.getFrameLowering(); 622 Offset += TFI->getFrameIndexReference(*AP.MF, 623 MI->getOperand(0).getIndex(), Reg); 624 Deref = true; 625 } 626 if (Reg == 0) { 627 // Suppress offset, it is not meaningful here. 628 OS << "undef"; 629 // NOTE: Want this comment at start of line, don't emit with AddComment. 630 AP.OutStreamer.EmitRawText(OS.str()); 631 return true; 632 } 633 if (Deref) 634 OS << '['; 635 OS << AP.TM.getRegisterInfo()->getName(Reg); 636 } 637 638 if (Deref) 639 OS << '+' << Offset << ']'; 640 641 // NOTE: Want this comment at start of line, don't emit with AddComment. 642 AP.OutStreamer.EmitRawText(OS.str()); 643 return true; 644} 645 646AsmPrinter::CFIMoveType AsmPrinter::needsCFIMoves() { 647 if (MAI->getExceptionHandlingType() == ExceptionHandling::DwarfCFI && 648 MF->getFunction()->needsUnwindTableEntry()) 649 return CFI_M_EH; 650 651 if (MMI->hasDebugInfo()) 652 return CFI_M_Debug; 653 654 return CFI_M_None; 655} 656 657bool AsmPrinter::needsSEHMoves() { 658 return MAI->getExceptionHandlingType() == ExceptionHandling::Win64 && 659 MF->getFunction()->needsUnwindTableEntry(); 660} 661 662bool AsmPrinter::needsRelocationsForDwarfStringPool() const { 663 return MAI->doesDwarfUseRelocationsAcrossSections(); 664} 665 666void AsmPrinter::emitPrologLabel(const MachineInstr &MI) { 667 const MCSymbol *Label = MI.getOperand(0).getMCSymbol(); 668 669 if (MAI->getExceptionHandlingType() != ExceptionHandling::DwarfCFI) 670 return; 671 672 if (needsCFIMoves() == CFI_M_None) 673 return; 674 675 if (MMI->getCompactUnwindEncoding() != 0) 676 OutStreamer.EmitCompactUnwindEncoding(MMI->getCompactUnwindEncoding()); 677 678 const MachineModuleInfo &MMI = MF->getMMI(); 679 const std::vector<MCCFIInstruction> &Instrs = MMI.getFrameInstructions(); 680 bool FoundOne = false; 681 (void)FoundOne; 682 for (std::vector<MCCFIInstruction>::const_iterator I = Instrs.begin(), 683 E = Instrs.end(); I != E; ++I) { 684 if (I->getLabel() == Label) { 685 emitCFIInstruction(*I); 686 FoundOne = true; 687 } 688 } 689 assert(FoundOne); 690} 691 692/// EmitFunctionBody - This method emits the body and trailer for a 693/// function. 694void AsmPrinter::EmitFunctionBody() { 695 // Emit target-specific gunk before the function body. 696 EmitFunctionBodyStart(); 697 698 bool ShouldPrintDebugScopes = DD && MMI->hasDebugInfo(); 699 700 // Print out code for the function. 701 bool HasAnyRealCode = false; 702 const MachineInstr *LastMI = 0; 703 for (MachineFunction::const_iterator I = MF->begin(), E = MF->end(); 704 I != E; ++I) { 705 // Print a label for the basic block. 706 EmitBasicBlockStart(I); 707 for (MachineBasicBlock::const_iterator II = I->begin(), IE = I->end(); 708 II != IE; ++II) { 709 LastMI = II; 710 711 // Print the assembly for the instruction. 712 if (!II->isLabel() && !II->isImplicitDef() && !II->isKill() && 713 !II->isDebugValue()) { 714 HasAnyRealCode = true; 715 ++EmittedInsts; 716 } 717 718 if (ShouldPrintDebugScopes) { 719 NamedRegionTimer T(DbgTimerName, DWARFGroupName, TimePassesIsEnabled); 720 DD->beginInstruction(II); 721 } 722 723 if (isVerbose()) 724 emitComments(*II, OutStreamer.GetCommentOS()); 725 726 switch (II->getOpcode()) { 727 case TargetOpcode::PROLOG_LABEL: 728 emitPrologLabel(*II); 729 break; 730 731 case TargetOpcode::EH_LABEL: 732 case TargetOpcode::GC_LABEL: 733 OutStreamer.EmitLabel(II->getOperand(0).getMCSymbol()); 734 break; 735 case TargetOpcode::INLINEASM: 736 EmitInlineAsm(II); 737 break; 738 case TargetOpcode::DBG_VALUE: 739 if (isVerbose()) { 740 if (!emitDebugValueComment(II, *this)) 741 EmitInstruction(II); 742 } 743 break; 744 case TargetOpcode::IMPLICIT_DEF: 745 if (isVerbose()) emitImplicitDef(II); 746 break; 747 case TargetOpcode::KILL: 748 if (isVerbose()) emitKill(II, *this); 749 break; 750 default: 751 if (!TM.hasMCUseLoc()) 752 MCLineEntry::Make(&OutStreamer, getCurrentSection()); 753 754 EmitInstruction(II); 755 break; 756 } 757 758 if (ShouldPrintDebugScopes) { 759 NamedRegionTimer T(DbgTimerName, DWARFGroupName, TimePassesIsEnabled); 760 DD->endInstruction(II); 761 } 762 } 763 } 764 765 // If the last instruction was a prolog label, then we have a situation where 766 // we emitted a prolog but no function body. This results in the ending prolog 767 // label equaling the end of function label and an invalid "row" in the 768 // FDE. We need to emit a noop in this situation so that the FDE's rows are 769 // valid. 770 bool RequiresNoop = LastMI && LastMI->isPrologLabel(); 771 772 // If the function is empty and the object file uses .subsections_via_symbols, 773 // then we need to emit *something* to the function body to prevent the 774 // labels from collapsing together. Just emit a noop. 775 if ((MAI->hasSubsectionsViaSymbols() && !HasAnyRealCode) || RequiresNoop) { 776 MCInst Noop; 777 TM.getInstrInfo()->getNoopForMachoTarget(Noop); 778 if (Noop.getOpcode()) { 779 OutStreamer.AddComment("avoids zero-length function"); 780 OutStreamer.EmitInstruction(Noop); 781 } else // Target not mc-ized yet. 782 OutStreamer.EmitRawText(StringRef("\tnop\n")); 783 } 784 785 const Function *F = MF->getFunction(); 786 for (Function::const_iterator i = F->begin(), e = F->end(); i != e; ++i) { 787 const BasicBlock *BB = i; 788 if (!BB->hasAddressTaken()) 789 continue; 790 MCSymbol *Sym = GetBlockAddressSymbol(BB); 791 if (Sym->isDefined()) 792 continue; 793 OutStreamer.AddComment("Address of block that was removed by CodeGen"); 794 OutStreamer.EmitLabel(Sym); 795 } 796 797 // Emit target-specific gunk after the function body. 798 EmitFunctionBodyEnd(); 799 800 // If the target wants a .size directive for the size of the function, emit 801 // it. 802 if (MAI->hasDotTypeDotSizeDirective()) { 803 // Create a symbol for the end of function, so we can get the size as 804 // difference between the function label and the temp label. 805 MCSymbol *FnEndLabel = OutContext.CreateTempSymbol(); 806 OutStreamer.EmitLabel(FnEndLabel); 807 808 const MCExpr *SizeExp = 809 MCBinaryExpr::CreateSub(MCSymbolRefExpr::Create(FnEndLabel, OutContext), 810 MCSymbolRefExpr::Create(CurrentFnSymForSize, 811 OutContext), 812 OutContext); 813 OutStreamer.EmitELFSize(CurrentFnSym, SizeExp); 814 } 815 816 // Emit post-function debug information. 817 if (DD) { 818 NamedRegionTimer T(DbgTimerName, DWARFGroupName, TimePassesIsEnabled); 819 DD->endFunction(MF); 820 } 821 if (DE) { 822 NamedRegionTimer T(EHTimerName, DWARFGroupName, TimePassesIsEnabled); 823 DE->EndFunction(); 824 } 825 MMI->EndFunction(); 826 827 // Print out jump tables referenced by the function. 828 EmitJumpTableInfo(); 829 830 OutStreamer.AddBlankLine(); 831} 832 833/// EmitDwarfRegOp - Emit dwarf register operation. 834void AsmPrinter::EmitDwarfRegOp(const MachineLocation &MLoc, 835 bool Indirect) const { 836 const TargetRegisterInfo *TRI = TM.getRegisterInfo(); 837 int Reg = TRI->getDwarfRegNum(MLoc.getReg(), false); 838 839 for (MCSuperRegIterator SR(MLoc.getReg(), TRI); SR.isValid() && Reg < 0; 840 ++SR) { 841 Reg = TRI->getDwarfRegNum(*SR, false); 842 // FIXME: Get the bit range this register uses of the superregister 843 // so that we can produce a DW_OP_bit_piece 844 } 845 846 // FIXME: Handle cases like a super register being encoded as 847 // DW_OP_reg 32 DW_OP_piece 4 DW_OP_reg 33 848 849 // FIXME: We have no reasonable way of handling errors in here. The 850 // caller might be in the middle of an dwarf expression. We should 851 // probably assert that Reg >= 0 once debug info generation is more mature. 852 853 if (MLoc.isIndirect() || Indirect) { 854 if (Reg < 32) { 855 OutStreamer.AddComment( 856 dwarf::OperationEncodingString(dwarf::DW_OP_breg0 + Reg)); 857 EmitInt8(dwarf::DW_OP_breg0 + Reg); 858 } else { 859 OutStreamer.AddComment("DW_OP_bregx"); 860 EmitInt8(dwarf::DW_OP_bregx); 861 OutStreamer.AddComment(Twine(Reg)); 862 EmitULEB128(Reg); 863 } 864 EmitSLEB128(!MLoc.isIndirect() ? 0 : MLoc.getOffset()); 865 if (MLoc.isIndirect() && Indirect) 866 EmitInt8(dwarf::DW_OP_deref); 867 } else { 868 if (Reg < 32) { 869 OutStreamer.AddComment( 870 dwarf::OperationEncodingString(dwarf::DW_OP_reg0 + Reg)); 871 EmitInt8(dwarf::DW_OP_reg0 + Reg); 872 } else { 873 OutStreamer.AddComment("DW_OP_regx"); 874 EmitInt8(dwarf::DW_OP_regx); 875 OutStreamer.AddComment(Twine(Reg)); 876 EmitULEB128(Reg); 877 } 878 } 879 880 // FIXME: Produce a DW_OP_bit_piece if we used a superregister 881} 882 883bool AsmPrinter::doFinalization(Module &M) { 884 // Emit global variables. 885 for (Module::const_global_iterator I = M.global_begin(), E = M.global_end(); 886 I != E; ++I) 887 EmitGlobalVariable(I); 888 889 // Emit visibility info for declarations 890 for (Module::const_iterator I = M.begin(), E = M.end(); I != E; ++I) { 891 const Function &F = *I; 892 if (!F.isDeclaration()) 893 continue; 894 GlobalValue::VisibilityTypes V = F.getVisibility(); 895 if (V == GlobalValue::DefaultVisibility) 896 continue; 897 898 MCSymbol *Name = getSymbol(&F); 899 EmitVisibility(Name, V, false); 900 } 901 902 // Emit module flags. 903 SmallVector<Module::ModuleFlagEntry, 8> ModuleFlags; 904 M.getModuleFlagsMetadata(ModuleFlags); 905 if (!ModuleFlags.empty()) 906 getObjFileLowering().emitModuleFlags(OutStreamer, ModuleFlags, Mang, TM); 907 908 // Make sure we wrote out everything we need. 909 OutStreamer.Flush(); 910 911 // Finalize debug and EH information. 912 if (DE) { 913 { 914 NamedRegionTimer T(EHTimerName, DWARFGroupName, TimePassesIsEnabled); 915 DE->EndModule(); 916 } 917 delete DE; DE = 0; 918 } 919 if (DD) { 920 { 921 NamedRegionTimer T(DbgTimerName, DWARFGroupName, TimePassesIsEnabled); 922 DD->endModule(); 923 } 924 delete DD; DD = 0; 925 } 926 927 // If the target wants to know about weak references, print them all. 928 if (MAI->getWeakRefDirective()) { 929 // FIXME: This is not lazy, it would be nice to only print weak references 930 // to stuff that is actually used. Note that doing so would require targets 931 // to notice uses in operands (due to constant exprs etc). This should 932 // happen with the MC stuff eventually. 933 934 // Print out module-level global variables here. 935 for (Module::const_global_iterator I = M.global_begin(), E = M.global_end(); 936 I != E; ++I) { 937 if (!I->hasExternalWeakLinkage()) continue; 938 OutStreamer.EmitSymbolAttribute(getSymbol(I), MCSA_WeakReference); 939 } 940 941 for (Module::const_iterator I = M.begin(), E = M.end(); I != E; ++I) { 942 if (!I->hasExternalWeakLinkage()) continue; 943 OutStreamer.EmitSymbolAttribute(getSymbol(I), MCSA_WeakReference); 944 } 945 } 946 947 if (MAI->hasSetDirective()) { 948 OutStreamer.AddBlankLine(); 949 for (Module::const_alias_iterator I = M.alias_begin(), E = M.alias_end(); 950 I != E; ++I) { 951 MCSymbol *Name = getSymbol(I); 952 953 const GlobalValue *GV = I->getAliasedGlobal(); 954 if (GV->isDeclaration()) { 955 report_fatal_error(Name->getName() + 956 ": Target doesn't support aliases to declarations"); 957 } 958 959 MCSymbol *Target = getSymbol(GV); 960 961 if (I->hasExternalLinkage() || !MAI->getWeakRefDirective()) 962 OutStreamer.EmitSymbolAttribute(Name, MCSA_Global); 963 else if (I->hasWeakLinkage() || I->hasLinkOnceLinkage()) 964 OutStreamer.EmitSymbolAttribute(Name, MCSA_WeakReference); 965 else 966 assert(I->hasLocalLinkage() && "Invalid alias linkage"); 967 968 EmitVisibility(Name, I->getVisibility()); 969 970 // Emit the directives as assignments aka .set: 971 OutStreamer.EmitAssignment(Name, 972 MCSymbolRefExpr::Create(Target, OutContext)); 973 } 974 } 975 976 GCModuleInfo *MI = getAnalysisIfAvailable<GCModuleInfo>(); 977 assert(MI && "AsmPrinter didn't require GCModuleInfo?"); 978 for (GCModuleInfo::iterator I = MI->end(), E = MI->begin(); I != E; ) 979 if (GCMetadataPrinter *MP = GetOrCreateGCPrinter(*--I)) 980 MP->finishAssembly(*this); 981 982 // Emit llvm.ident metadata in an '.ident' directive. 983 EmitModuleIdents(M); 984 985 // If we don't have any trampolines, then we don't require stack memory 986 // to be executable. Some targets have a directive to declare this. 987 Function *InitTrampolineIntrinsic = M.getFunction("llvm.init.trampoline"); 988 if (!InitTrampolineIntrinsic || InitTrampolineIntrinsic->use_empty()) 989 if (const MCSection *S = MAI->getNonexecutableStackSection(OutContext)) 990 OutStreamer.SwitchSection(S); 991 992 // Allow the target to emit any magic that it wants at the end of the file, 993 // after everything else has gone out. 994 EmitEndOfAsmFile(M); 995 996 delete Mang; Mang = 0; 997 MMI = 0; 998 999 OutStreamer.Finish(); 1000 OutStreamer.reset(); 1001 1002 return false; 1003} 1004 1005void AsmPrinter::SetupMachineFunction(MachineFunction &MF) { 1006 this->MF = &MF; 1007 // Get the function symbol. 1008 CurrentFnSym = getSymbol(MF.getFunction()); 1009 CurrentFnSymForSize = CurrentFnSym; 1010 1011 if (isVerbose()) 1012 LI = &getAnalysis<MachineLoopInfo>(); 1013} 1014 1015namespace { 1016 // SectionCPs - Keep track the alignment, constpool entries per Section. 1017 struct SectionCPs { 1018 const MCSection *S; 1019 unsigned Alignment; 1020 SmallVector<unsigned, 4> CPEs; 1021 SectionCPs(const MCSection *s, unsigned a) : S(s), Alignment(a) {} 1022 }; 1023} 1024 1025/// EmitConstantPool - Print to the current output stream assembly 1026/// representations of the constants in the constant pool MCP. This is 1027/// used to print out constants which have been "spilled to memory" by 1028/// the code generator. 1029/// 1030void AsmPrinter::EmitConstantPool() { 1031 const MachineConstantPool *MCP = MF->getConstantPool(); 1032 const std::vector<MachineConstantPoolEntry> &CP = MCP->getConstants(); 1033 if (CP.empty()) return; 1034 1035 // Calculate sections for constant pool entries. We collect entries to go into 1036 // the same section together to reduce amount of section switch statements. 1037 SmallVector<SectionCPs, 4> CPSections; 1038 for (unsigned i = 0, e = CP.size(); i != e; ++i) { 1039 const MachineConstantPoolEntry &CPE = CP[i]; 1040 unsigned Align = CPE.getAlignment(); 1041 1042 SectionKind Kind; 1043 switch (CPE.getRelocationInfo()) { 1044 default: llvm_unreachable("Unknown section kind"); 1045 case 2: Kind = SectionKind::getReadOnlyWithRel(); break; 1046 case 1: 1047 Kind = SectionKind::getReadOnlyWithRelLocal(); 1048 break; 1049 case 0: 1050 switch (TM.getDataLayout()->getTypeAllocSize(CPE.getType())) { 1051 case 4: Kind = SectionKind::getMergeableConst4(); break; 1052 case 8: Kind = SectionKind::getMergeableConst8(); break; 1053 case 16: Kind = SectionKind::getMergeableConst16();break; 1054 default: Kind = SectionKind::getMergeableConst(); break; 1055 } 1056 } 1057 1058 const MCSection *S = getObjFileLowering().getSectionForConstant(Kind); 1059 1060 // The number of sections are small, just do a linear search from the 1061 // last section to the first. 1062 bool Found = false; 1063 unsigned SecIdx = CPSections.size(); 1064 while (SecIdx != 0) { 1065 if (CPSections[--SecIdx].S == S) { 1066 Found = true; 1067 break; 1068 } 1069 } 1070 if (!Found) { 1071 SecIdx = CPSections.size(); 1072 CPSections.push_back(SectionCPs(S, Align)); 1073 } 1074 1075 if (Align > CPSections[SecIdx].Alignment) 1076 CPSections[SecIdx].Alignment = Align; 1077 CPSections[SecIdx].CPEs.push_back(i); 1078 } 1079 1080 // Now print stuff into the calculated sections. 1081 for (unsigned i = 0, e = CPSections.size(); i != e; ++i) { 1082 OutStreamer.SwitchSection(CPSections[i].S); 1083 EmitAlignment(Log2_32(CPSections[i].Alignment)); 1084 1085 unsigned Offset = 0; 1086 for (unsigned j = 0, ee = CPSections[i].CPEs.size(); j != ee; ++j) { 1087 unsigned CPI = CPSections[i].CPEs[j]; 1088 MachineConstantPoolEntry CPE = CP[CPI]; 1089 1090 // Emit inter-object padding for alignment. 1091 unsigned AlignMask = CPE.getAlignment() - 1; 1092 unsigned NewOffset = (Offset + AlignMask) & ~AlignMask; 1093 OutStreamer.EmitZeros(NewOffset - Offset); 1094 1095 Type *Ty = CPE.getType(); 1096 Offset = NewOffset + TM.getDataLayout()->getTypeAllocSize(Ty); 1097 OutStreamer.EmitLabel(GetCPISymbol(CPI)); 1098 1099 if (CPE.isMachineConstantPoolEntry()) 1100 EmitMachineConstantPoolValue(CPE.Val.MachineCPVal); 1101 else 1102 EmitGlobalConstant(CPE.Val.ConstVal); 1103 } 1104 } 1105} 1106 1107/// EmitJumpTableInfo - Print assembly representations of the jump tables used 1108/// by the current function to the current output stream. 1109/// 1110void AsmPrinter::EmitJumpTableInfo() { 1111 const MachineJumpTableInfo *MJTI = MF->getJumpTableInfo(); 1112 if (MJTI == 0) return; 1113 if (MJTI->getEntryKind() == MachineJumpTableInfo::EK_Inline) return; 1114 const std::vector<MachineJumpTableEntry> &JT = MJTI->getJumpTables(); 1115 if (JT.empty()) return; 1116 1117 // Pick the directive to use to print the jump table entries, and switch to 1118 // the appropriate section. 1119 const Function *F = MF->getFunction(); 1120 bool JTInDiffSection = false; 1121 if (// In PIC mode, we need to emit the jump table to the same section as the 1122 // function body itself, otherwise the label differences won't make sense. 1123 // FIXME: Need a better predicate for this: what about custom entries? 1124 MJTI->getEntryKind() == MachineJumpTableInfo::EK_LabelDifference32 || 1125 // We should also do if the section name is NULL or function is declared 1126 // in discardable section 1127 // FIXME: this isn't the right predicate, should be based on the MCSection 1128 // for the function. 1129 F->isWeakForLinker()) { 1130 OutStreamer.SwitchSection(getObjFileLowering().SectionForGlobal(F,Mang,TM)); 1131 } else { 1132 // Otherwise, drop it in the readonly section. 1133 const MCSection *ReadOnlySection = 1134 getObjFileLowering().getSectionForConstant(SectionKind::getReadOnly()); 1135 OutStreamer.SwitchSection(ReadOnlySection); 1136 JTInDiffSection = true; 1137 } 1138 1139 EmitAlignment(Log2_32(MJTI->getEntryAlignment(*TM.getDataLayout()))); 1140 1141 // Jump tables in code sections are marked with a data_region directive 1142 // where that's supported. 1143 if (!JTInDiffSection) 1144 OutStreamer.EmitDataRegion(MCDR_DataRegionJT32); 1145 1146 for (unsigned JTI = 0, e = JT.size(); JTI != e; ++JTI) { 1147 const std::vector<MachineBasicBlock*> &JTBBs = JT[JTI].MBBs; 1148 1149 // If this jump table was deleted, ignore it. 1150 if (JTBBs.empty()) continue; 1151 1152 // For the EK_LabelDifference32 entry, if the target supports .set, emit a 1153 // .set directive for each unique entry. This reduces the number of 1154 // relocations the assembler will generate for the jump table. 1155 if (MJTI->getEntryKind() == MachineJumpTableInfo::EK_LabelDifference32 && 1156 MAI->hasSetDirective()) { 1157 SmallPtrSet<const MachineBasicBlock*, 16> EmittedSets; 1158 const TargetLowering *TLI = TM.getTargetLowering(); 1159 const MCExpr *Base = TLI->getPICJumpTableRelocBaseExpr(MF,JTI,OutContext); 1160 for (unsigned ii = 0, ee = JTBBs.size(); ii != ee; ++ii) { 1161 const MachineBasicBlock *MBB = JTBBs[ii]; 1162 if (!EmittedSets.insert(MBB)) continue; 1163 1164 // .set LJTSet, LBB32-base 1165 const MCExpr *LHS = 1166 MCSymbolRefExpr::Create(MBB->getSymbol(), OutContext); 1167 OutStreamer.EmitAssignment(GetJTSetSymbol(JTI, MBB->getNumber()), 1168 MCBinaryExpr::CreateSub(LHS, Base, OutContext)); 1169 } 1170 } 1171 1172 // On some targets (e.g. Darwin) we want to emit two consecutive labels 1173 // before each jump table. The first label is never referenced, but tells 1174 // the assembler and linker the extents of the jump table object. The 1175 // second label is actually referenced by the code. 1176 if (JTInDiffSection && MAI->getLinkerPrivateGlobalPrefix()[0]) 1177 // FIXME: This doesn't have to have any specific name, just any randomly 1178 // named and numbered 'l' label would work. Simplify GetJTISymbol. 1179 OutStreamer.EmitLabel(GetJTISymbol(JTI, true)); 1180 1181 OutStreamer.EmitLabel(GetJTISymbol(JTI)); 1182 1183 for (unsigned ii = 0, ee = JTBBs.size(); ii != ee; ++ii) 1184 EmitJumpTableEntry(MJTI, JTBBs[ii], JTI); 1185 } 1186 if (!JTInDiffSection) 1187 OutStreamer.EmitDataRegion(MCDR_DataRegionEnd); 1188} 1189 1190/// EmitJumpTableEntry - Emit a jump table entry for the specified MBB to the 1191/// current stream. 1192void AsmPrinter::EmitJumpTableEntry(const MachineJumpTableInfo *MJTI, 1193 const MachineBasicBlock *MBB, 1194 unsigned UID) const { 1195 assert(MBB && MBB->getNumber() >= 0 && "Invalid basic block"); 1196 const MCExpr *Value = 0; 1197 switch (MJTI->getEntryKind()) { 1198 case MachineJumpTableInfo::EK_Inline: 1199 llvm_unreachable("Cannot emit EK_Inline jump table entry"); 1200 case MachineJumpTableInfo::EK_Custom32: 1201 Value = TM.getTargetLowering()->LowerCustomJumpTableEntry(MJTI, MBB, UID, 1202 OutContext); 1203 break; 1204 case MachineJumpTableInfo::EK_BlockAddress: 1205 // EK_BlockAddress - Each entry is a plain address of block, e.g.: 1206 // .word LBB123 1207 Value = MCSymbolRefExpr::Create(MBB->getSymbol(), OutContext); 1208 break; 1209 case MachineJumpTableInfo::EK_GPRel32BlockAddress: { 1210 // EK_GPRel32BlockAddress - Each entry is an address of block, encoded 1211 // with a relocation as gp-relative, e.g.: 1212 // .gprel32 LBB123 1213 MCSymbol *MBBSym = MBB->getSymbol(); 1214 OutStreamer.EmitGPRel32Value(MCSymbolRefExpr::Create(MBBSym, OutContext)); 1215 return; 1216 } 1217 1218 case MachineJumpTableInfo::EK_GPRel64BlockAddress: { 1219 // EK_GPRel64BlockAddress - Each entry is an address of block, encoded 1220 // with a relocation as gp-relative, e.g.: 1221 // .gpdword LBB123 1222 MCSymbol *MBBSym = MBB->getSymbol(); 1223 OutStreamer.EmitGPRel64Value(MCSymbolRefExpr::Create(MBBSym, OutContext)); 1224 return; 1225 } 1226 1227 case MachineJumpTableInfo::EK_LabelDifference32: { 1228 // EK_LabelDifference32 - Each entry is the address of the block minus 1229 // the address of the jump table. This is used for PIC jump tables where 1230 // gprel32 is not supported. e.g.: 1231 // .word LBB123 - LJTI1_2 1232 // If the .set directive is supported, this is emitted as: 1233 // .set L4_5_set_123, LBB123 - LJTI1_2 1234 // .word L4_5_set_123 1235 1236 // If we have emitted set directives for the jump table entries, print 1237 // them rather than the entries themselves. If we're emitting PIC, then 1238 // emit the table entries as differences between two text section labels. 1239 if (MAI->hasSetDirective()) { 1240 // If we used .set, reference the .set's symbol. 1241 Value = MCSymbolRefExpr::Create(GetJTSetSymbol(UID, MBB->getNumber()), 1242 OutContext); 1243 break; 1244 } 1245 // Otherwise, use the difference as the jump table entry. 1246 Value = MCSymbolRefExpr::Create(MBB->getSymbol(), OutContext); 1247 const MCExpr *JTI = MCSymbolRefExpr::Create(GetJTISymbol(UID), OutContext); 1248 Value = MCBinaryExpr::CreateSub(Value, JTI, OutContext); 1249 break; 1250 } 1251 } 1252 1253 assert(Value && "Unknown entry kind!"); 1254 1255 unsigned EntrySize = MJTI->getEntrySize(*TM.getDataLayout()); 1256 OutStreamer.EmitValue(Value, EntrySize); 1257} 1258 1259 1260/// EmitSpecialLLVMGlobal - Check to see if the specified global is a 1261/// special global used by LLVM. If so, emit it and return true, otherwise 1262/// do nothing and return false. 1263bool AsmPrinter::EmitSpecialLLVMGlobal(const GlobalVariable *GV) { 1264 if (GV->getName() == "llvm.used") { 1265 if (MAI->hasNoDeadStrip()) // No need to emit this at all. 1266 EmitLLVMUsedList(cast<ConstantArray>(GV->getInitializer())); 1267 return true; 1268 } 1269 1270 // Ignore debug and non-emitted data. This handles llvm.compiler.used. 1271 if (GV->getSection() == "llvm.metadata" || 1272 GV->hasAvailableExternallyLinkage()) 1273 return true; 1274 1275 if (!GV->hasAppendingLinkage()) return false; 1276 1277 assert(GV->hasInitializer() && "Not a special LLVM global!"); 1278 1279 if (GV->getName() == "llvm.global_ctors") { 1280 EmitXXStructorList(GV->getInitializer(), /* isCtor */ true); 1281 1282 if (TM.getRelocationModel() == Reloc::Static && 1283 MAI->hasStaticCtorDtorReferenceInStaticMode()) { 1284 StringRef Sym(".constructors_used"); 1285 OutStreamer.EmitSymbolAttribute(OutContext.GetOrCreateSymbol(Sym), 1286 MCSA_Reference); 1287 } 1288 return true; 1289 } 1290 1291 if (GV->getName() == "llvm.global_dtors") { 1292 EmitXXStructorList(GV->getInitializer(), /* isCtor */ false); 1293 1294 if (TM.getRelocationModel() == Reloc::Static && 1295 MAI->hasStaticCtorDtorReferenceInStaticMode()) { 1296 StringRef Sym(".destructors_used"); 1297 OutStreamer.EmitSymbolAttribute(OutContext.GetOrCreateSymbol(Sym), 1298 MCSA_Reference); 1299 } 1300 return true; 1301 } 1302 1303 return false; 1304} 1305 1306/// EmitLLVMUsedList - For targets that define a MAI::UsedDirective, mark each 1307/// global in the specified llvm.used list for which emitUsedDirectiveFor 1308/// is true, as being used with this directive. 1309void AsmPrinter::EmitLLVMUsedList(const ConstantArray *InitList) { 1310 // Should be an array of 'i8*'. 1311 for (unsigned i = 0, e = InitList->getNumOperands(); i != e; ++i) { 1312 const GlobalValue *GV = 1313 dyn_cast<GlobalValue>(InitList->getOperand(i)->stripPointerCasts()); 1314 if (GV && getObjFileLowering().shouldEmitUsedDirectiveFor(GV, Mang)) 1315 OutStreamer.EmitSymbolAttribute(getSymbol(GV), MCSA_NoDeadStrip); 1316 } 1317} 1318 1319/// EmitXXStructorList - Emit the ctor or dtor list taking into account the init 1320/// priority. 1321void AsmPrinter::EmitXXStructorList(const Constant *List, bool isCtor) { 1322 // Should be an array of '{ int, void ()* }' structs. The first value is the 1323 // init priority. 1324 if (!isa<ConstantArray>(List)) return; 1325 1326 // Sanity check the structors list. 1327 const ConstantArray *InitList = dyn_cast<ConstantArray>(List); 1328 if (!InitList) return; // Not an array! 1329 StructType *ETy = dyn_cast<StructType>(InitList->getType()->getElementType()); 1330 if (!ETy || ETy->getNumElements() != 2) return; // Not an array of pairs! 1331 if (!isa<IntegerType>(ETy->getTypeAtIndex(0U)) || 1332 !isa<PointerType>(ETy->getTypeAtIndex(1U))) return; // Not (int, ptr). 1333 1334 // Gather the structors in a form that's convenient for sorting by priority. 1335 typedef std::pair<unsigned, Constant *> Structor; 1336 SmallVector<Structor, 8> Structors; 1337 for (unsigned i = 0, e = InitList->getNumOperands(); i != e; ++i) { 1338 ConstantStruct *CS = dyn_cast<ConstantStruct>(InitList->getOperand(i)); 1339 if (!CS) continue; // Malformed. 1340 if (CS->getOperand(1)->isNullValue()) 1341 break; // Found a null terminator, skip the rest. 1342 ConstantInt *Priority = dyn_cast<ConstantInt>(CS->getOperand(0)); 1343 if (!Priority) continue; // Malformed. 1344 Structors.push_back(std::make_pair(Priority->getLimitedValue(65535), 1345 CS->getOperand(1))); 1346 } 1347 1348 // Emit the function pointers in the target-specific order 1349 const DataLayout *DL = TM.getDataLayout(); 1350 unsigned Align = Log2_32(DL->getPointerPrefAlignment()); 1351 std::stable_sort(Structors.begin(), Structors.end(), less_first()); 1352 for (unsigned i = 0, e = Structors.size(); i != e; ++i) { 1353 const MCSection *OutputSection = 1354 (isCtor ? 1355 getObjFileLowering().getStaticCtorSection(Structors[i].first) : 1356 getObjFileLowering().getStaticDtorSection(Structors[i].first)); 1357 OutStreamer.SwitchSection(OutputSection); 1358 if (OutStreamer.getCurrentSection() != OutStreamer.getPreviousSection()) 1359 EmitAlignment(Align); 1360 EmitXXStructor(Structors[i].second); 1361 } 1362} 1363 1364void AsmPrinter::EmitModuleIdents(Module &M) { 1365 if (!MAI->hasIdentDirective()) 1366 return; 1367 1368 if (const NamedMDNode *NMD = M.getNamedMetadata("llvm.ident")) { 1369 for (unsigned i = 0, e = NMD->getNumOperands(); i != e; ++i) { 1370 const MDNode *N = NMD->getOperand(i); 1371 assert(N->getNumOperands() == 1 && 1372 "llvm.ident metadata entry can have only one operand"); 1373 const MDString *S = cast<MDString>(N->getOperand(0)); 1374 OutStreamer.EmitIdent(S->getString()); 1375 } 1376 } 1377} 1378 1379//===--------------------------------------------------------------------===// 1380// Emission and print routines 1381// 1382 1383/// EmitInt8 - Emit a byte directive and value. 1384/// 1385void AsmPrinter::EmitInt8(int Value) const { 1386 OutStreamer.EmitIntValue(Value, 1); 1387} 1388 1389/// EmitInt16 - Emit a short directive and value. 1390/// 1391void AsmPrinter::EmitInt16(int Value) const { 1392 OutStreamer.EmitIntValue(Value, 2); 1393} 1394 1395/// EmitInt32 - Emit a long directive and value. 1396/// 1397void AsmPrinter::EmitInt32(int Value) const { 1398 OutStreamer.EmitIntValue(Value, 4); 1399} 1400 1401/// EmitLabelDifference - Emit something like ".long Hi-Lo" where the size 1402/// in bytes of the directive is specified by Size and Hi/Lo specify the 1403/// labels. This implicitly uses .set if it is available. 1404void AsmPrinter::EmitLabelDifference(const MCSymbol *Hi, const MCSymbol *Lo, 1405 unsigned Size) const { 1406 // Get the Hi-Lo expression. 1407 const MCExpr *Diff = 1408 MCBinaryExpr::CreateSub(MCSymbolRefExpr::Create(Hi, OutContext), 1409 MCSymbolRefExpr::Create(Lo, OutContext), 1410 OutContext); 1411 1412 if (!MAI->hasSetDirective()) { 1413 OutStreamer.EmitValue(Diff, Size); 1414 return; 1415 } 1416 1417 // Otherwise, emit with .set (aka assignment). 1418 MCSymbol *SetLabel = GetTempSymbol("set", SetCounter++); 1419 OutStreamer.EmitAssignment(SetLabel, Diff); 1420 OutStreamer.EmitSymbolValue(SetLabel, Size); 1421} 1422 1423/// EmitLabelOffsetDifference - Emit something like ".long Hi+Offset-Lo" 1424/// where the size in bytes of the directive is specified by Size and Hi/Lo 1425/// specify the labels. This implicitly uses .set if it is available. 1426void AsmPrinter::EmitLabelOffsetDifference(const MCSymbol *Hi, uint64_t Offset, 1427 const MCSymbol *Lo, unsigned Size) 1428 const { 1429 1430 // Emit Hi+Offset - Lo 1431 // Get the Hi+Offset expression. 1432 const MCExpr *Plus = 1433 MCBinaryExpr::CreateAdd(MCSymbolRefExpr::Create(Hi, OutContext), 1434 MCConstantExpr::Create(Offset, OutContext), 1435 OutContext); 1436 1437 // Get the Hi+Offset-Lo expression. 1438 const MCExpr *Diff = 1439 MCBinaryExpr::CreateSub(Plus, 1440 MCSymbolRefExpr::Create(Lo, OutContext), 1441 OutContext); 1442 1443 if (!MAI->hasSetDirective()) 1444 OutStreamer.EmitValue(Diff, Size); 1445 else { 1446 // Otherwise, emit with .set (aka assignment). 1447 MCSymbol *SetLabel = GetTempSymbol("set", SetCounter++); 1448 OutStreamer.EmitAssignment(SetLabel, Diff); 1449 OutStreamer.EmitSymbolValue(SetLabel, Size); 1450 } 1451} 1452 1453/// EmitLabelPlusOffset - Emit something like ".long Label+Offset" 1454/// where the size in bytes of the directive is specified by Size and Label 1455/// specifies the label. This implicitly uses .set if it is available. 1456void AsmPrinter::EmitLabelPlusOffset(const MCSymbol *Label, uint64_t Offset, 1457 unsigned Size, bool IsSectionRelative) 1458 const { 1459 if (MAI->needsDwarfSectionOffsetDirective() && IsSectionRelative) { 1460 OutStreamer.EmitCOFFSecRel32(Label); 1461 return; 1462 } 1463 1464 // Emit Label+Offset (or just Label if Offset is zero) 1465 const MCExpr *Expr = MCSymbolRefExpr::Create(Label, OutContext); 1466 if (Offset) 1467 Expr = MCBinaryExpr::CreateAdd(Expr, 1468 MCConstantExpr::Create(Offset, OutContext), 1469 OutContext); 1470 1471 OutStreamer.EmitValue(Expr, Size); 1472} 1473 1474 1475//===----------------------------------------------------------------------===// 1476 1477// EmitAlignment - Emit an alignment directive to the specified power of 1478// two boundary. For example, if you pass in 3 here, you will get an 8 1479// byte alignment. If a global value is specified, and if that global has 1480// an explicit alignment requested, it will override the alignment request 1481// if required for correctness. 1482// 1483void AsmPrinter::EmitAlignment(unsigned NumBits, const GlobalValue *GV) const { 1484 if (GV) NumBits = getGVAlignmentLog2(GV, *TM.getDataLayout(), NumBits); 1485 1486 if (NumBits == 0) return; // 1-byte aligned: no need to emit alignment. 1487 1488 if (getCurrentSection()->getKind().isText()) 1489 OutStreamer.EmitCodeAlignment(1 << NumBits); 1490 else 1491 OutStreamer.EmitValueToAlignment(1 << NumBits, 0, 1, 0); 1492} 1493 1494//===----------------------------------------------------------------------===// 1495// Constant emission. 1496//===----------------------------------------------------------------------===// 1497 1498/// lowerConstant - Lower the specified LLVM Constant to an MCExpr. 1499/// 1500static const MCExpr *lowerConstant(const Constant *CV, AsmPrinter &AP) { 1501 MCContext &Ctx = AP.OutContext; 1502 1503 if (CV->isNullValue() || isa<UndefValue>(CV)) 1504 return MCConstantExpr::Create(0, Ctx); 1505 1506 if (const ConstantInt *CI = dyn_cast<ConstantInt>(CV)) 1507 return MCConstantExpr::Create(CI->getZExtValue(), Ctx); 1508 1509 if (const GlobalValue *GV = dyn_cast<GlobalValue>(CV)) 1510 return MCSymbolRefExpr::Create(AP.getSymbol(GV), Ctx); 1511 1512 if (const BlockAddress *BA = dyn_cast<BlockAddress>(CV)) 1513 return MCSymbolRefExpr::Create(AP.GetBlockAddressSymbol(BA), Ctx); 1514 1515 const ConstantExpr *CE = dyn_cast<ConstantExpr>(CV); 1516 if (CE == 0) { 1517 llvm_unreachable("Unknown constant value to lower!"); 1518 } 1519 1520 switch (CE->getOpcode()) { 1521 default: 1522 // If the code isn't optimized, there may be outstanding folding 1523 // opportunities. Attempt to fold the expression using DataLayout as a 1524 // last resort before giving up. 1525 if (Constant *C = 1526 ConstantFoldConstantExpression(CE, AP.TM.getDataLayout())) 1527 if (C != CE) 1528 return lowerConstant(C, AP); 1529 1530 // Otherwise report the problem to the user. 1531 { 1532 std::string S; 1533 raw_string_ostream OS(S); 1534 OS << "Unsupported expression in static initializer: "; 1535 WriteAsOperand(OS, CE, /*PrintType=*/false, 1536 !AP.MF ? 0 : AP.MF->getFunction()->getParent()); 1537 report_fatal_error(OS.str()); 1538 } 1539 case Instruction::GetElementPtr: { 1540 const DataLayout &DL = *AP.TM.getDataLayout(); 1541 // Generate a symbolic expression for the byte address 1542 APInt OffsetAI(DL.getPointerTypeSizeInBits(CE->getType()), 0); 1543 cast<GEPOperator>(CE)->accumulateConstantOffset(DL, OffsetAI); 1544 1545 const MCExpr *Base = lowerConstant(CE->getOperand(0), AP); 1546 if (!OffsetAI) 1547 return Base; 1548 1549 int64_t Offset = OffsetAI.getSExtValue(); 1550 return MCBinaryExpr::CreateAdd(Base, MCConstantExpr::Create(Offset, Ctx), 1551 Ctx); 1552 } 1553 1554 case Instruction::Trunc: 1555 // We emit the value and depend on the assembler to truncate the generated 1556 // expression properly. This is important for differences between 1557 // blockaddress labels. Since the two labels are in the same function, it 1558 // is reasonable to treat their delta as a 32-bit value. 1559 // FALL THROUGH. 1560 case Instruction::BitCast: 1561 return lowerConstant(CE->getOperand(0), AP); 1562 1563 case Instruction::IntToPtr: { 1564 const DataLayout &DL = *AP.TM.getDataLayout(); 1565 // Handle casts to pointers by changing them into casts to the appropriate 1566 // integer type. This promotes constant folding and simplifies this code. 1567 Constant *Op = CE->getOperand(0); 1568 Op = ConstantExpr::getIntegerCast(Op, DL.getIntPtrType(CV->getType()), 1569 false/*ZExt*/); 1570 return lowerConstant(Op, AP); 1571 } 1572 1573 case Instruction::PtrToInt: { 1574 const DataLayout &DL = *AP.TM.getDataLayout(); 1575 // Support only foldable casts to/from pointers that can be eliminated by 1576 // changing the pointer to the appropriately sized integer type. 1577 Constant *Op = CE->getOperand(0); 1578 Type *Ty = CE->getType(); 1579 1580 const MCExpr *OpExpr = lowerConstant(Op, AP); 1581 1582 // We can emit the pointer value into this slot if the slot is an 1583 // integer slot equal to the size of the pointer. 1584 if (DL.getTypeAllocSize(Ty) == DL.getTypeAllocSize(Op->getType())) 1585 return OpExpr; 1586 1587 // Otherwise the pointer is smaller than the resultant integer, mask off 1588 // the high bits so we are sure to get a proper truncation if the input is 1589 // a constant expr. 1590 unsigned InBits = DL.getTypeAllocSizeInBits(Op->getType()); 1591 const MCExpr *MaskExpr = MCConstantExpr::Create(~0ULL >> (64-InBits), Ctx); 1592 return MCBinaryExpr::CreateAnd(OpExpr, MaskExpr, Ctx); 1593 } 1594 1595 // The MC library also has a right-shift operator, but it isn't consistently 1596 // signed or unsigned between different targets. 1597 case Instruction::Add: 1598 case Instruction::Sub: 1599 case Instruction::Mul: 1600 case Instruction::SDiv: 1601 case Instruction::SRem: 1602 case Instruction::Shl: 1603 case Instruction::And: 1604 case Instruction::Or: 1605 case Instruction::Xor: { 1606 const MCExpr *LHS = lowerConstant(CE->getOperand(0), AP); 1607 const MCExpr *RHS = lowerConstant(CE->getOperand(1), AP); 1608 switch (CE->getOpcode()) { 1609 default: llvm_unreachable("Unknown binary operator constant cast expr"); 1610 case Instruction::Add: return MCBinaryExpr::CreateAdd(LHS, RHS, Ctx); 1611 case Instruction::Sub: return MCBinaryExpr::CreateSub(LHS, RHS, Ctx); 1612 case Instruction::Mul: return MCBinaryExpr::CreateMul(LHS, RHS, Ctx); 1613 case Instruction::SDiv: return MCBinaryExpr::CreateDiv(LHS, RHS, Ctx); 1614 case Instruction::SRem: return MCBinaryExpr::CreateMod(LHS, RHS, Ctx); 1615 case Instruction::Shl: return MCBinaryExpr::CreateShl(LHS, RHS, Ctx); 1616 case Instruction::And: return MCBinaryExpr::CreateAnd(LHS, RHS, Ctx); 1617 case Instruction::Or: return MCBinaryExpr::CreateOr (LHS, RHS, Ctx); 1618 case Instruction::Xor: return MCBinaryExpr::CreateXor(LHS, RHS, Ctx); 1619 } 1620 } 1621 } 1622} 1623 1624static void emitGlobalConstantImpl(const Constant *C, AsmPrinter &AP); 1625 1626/// isRepeatedByteSequence - Determine whether the given value is 1627/// composed of a repeated sequence of identical bytes and return the 1628/// byte value. If it is not a repeated sequence, return -1. 1629static int isRepeatedByteSequence(const ConstantDataSequential *V) { 1630 StringRef Data = V->getRawDataValues(); 1631 assert(!Data.empty() && "Empty aggregates should be CAZ node"); 1632 char C = Data[0]; 1633 for (unsigned i = 1, e = Data.size(); i != e; ++i) 1634 if (Data[i] != C) return -1; 1635 return static_cast<uint8_t>(C); // Ensure 255 is not returned as -1. 1636} 1637 1638 1639/// isRepeatedByteSequence - Determine whether the given value is 1640/// composed of a repeated sequence of identical bytes and return the 1641/// byte value. If it is not a repeated sequence, return -1. 1642static int isRepeatedByteSequence(const Value *V, TargetMachine &TM) { 1643 1644 if (const ConstantInt *CI = dyn_cast<ConstantInt>(V)) { 1645 if (CI->getBitWidth() > 64) return -1; 1646 1647 uint64_t Size = TM.getDataLayout()->getTypeAllocSize(V->getType()); 1648 uint64_t Value = CI->getZExtValue(); 1649 1650 // Make sure the constant is at least 8 bits long and has a power 1651 // of 2 bit width. This guarantees the constant bit width is 1652 // always a multiple of 8 bits, avoiding issues with padding out 1653 // to Size and other such corner cases. 1654 if (CI->getBitWidth() < 8 || !isPowerOf2_64(CI->getBitWidth())) return -1; 1655 1656 uint8_t Byte = static_cast<uint8_t>(Value); 1657 1658 for (unsigned i = 1; i < Size; ++i) { 1659 Value >>= 8; 1660 if (static_cast<uint8_t>(Value) != Byte) return -1; 1661 } 1662 return Byte; 1663 } 1664 if (const ConstantArray *CA = dyn_cast<ConstantArray>(V)) { 1665 // Make sure all array elements are sequences of the same repeated 1666 // byte. 1667 assert(CA->getNumOperands() != 0 && "Should be a CAZ"); 1668 int Byte = isRepeatedByteSequence(CA->getOperand(0), TM); 1669 if (Byte == -1) return -1; 1670 1671 for (unsigned i = 1, e = CA->getNumOperands(); i != e; ++i) { 1672 int ThisByte = isRepeatedByteSequence(CA->getOperand(i), TM); 1673 if (ThisByte == -1) return -1; 1674 if (Byte != ThisByte) return -1; 1675 } 1676 return Byte; 1677 } 1678 1679 if (const ConstantDataSequential *CDS = dyn_cast<ConstantDataSequential>(V)) 1680 return isRepeatedByteSequence(CDS); 1681 1682 return -1; 1683} 1684 1685static void emitGlobalConstantDataSequential(const ConstantDataSequential *CDS, 1686 AsmPrinter &AP){ 1687 1688 // See if we can aggregate this into a .fill, if so, emit it as such. 1689 int Value = isRepeatedByteSequence(CDS, AP.TM); 1690 if (Value != -1) { 1691 uint64_t Bytes = AP.TM.getDataLayout()->getTypeAllocSize(CDS->getType()); 1692 // Don't emit a 1-byte object as a .fill. 1693 if (Bytes > 1) 1694 return AP.OutStreamer.EmitFill(Bytes, Value); 1695 } 1696 1697 // If this can be emitted with .ascii/.asciz, emit it as such. 1698 if (CDS->isString()) 1699 return AP.OutStreamer.EmitBytes(CDS->getAsString()); 1700 1701 // Otherwise, emit the values in successive locations. 1702 unsigned ElementByteSize = CDS->getElementByteSize(); 1703 if (isa<IntegerType>(CDS->getElementType())) { 1704 for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i) { 1705 if (AP.isVerbose()) 1706 AP.OutStreamer.GetCommentOS() << format("0x%" PRIx64 "\n", 1707 CDS->getElementAsInteger(i)); 1708 AP.OutStreamer.EmitIntValue(CDS->getElementAsInteger(i), 1709 ElementByteSize); 1710 } 1711 } else if (ElementByteSize == 4) { 1712 // FP Constants are printed as integer constants to avoid losing 1713 // precision. 1714 assert(CDS->getElementType()->isFloatTy()); 1715 for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i) { 1716 union { 1717 float F; 1718 uint32_t I; 1719 }; 1720 1721 F = CDS->getElementAsFloat(i); 1722 if (AP.isVerbose()) 1723 AP.OutStreamer.GetCommentOS() << "float " << F << '\n'; 1724 AP.OutStreamer.EmitIntValue(I, 4); 1725 } 1726 } else { 1727 assert(CDS->getElementType()->isDoubleTy()); 1728 for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i) { 1729 union { 1730 double F; 1731 uint64_t I; 1732 }; 1733 1734 F = CDS->getElementAsDouble(i); 1735 if (AP.isVerbose()) 1736 AP.OutStreamer.GetCommentOS() << "double " << F << '\n'; 1737 AP.OutStreamer.EmitIntValue(I, 8); 1738 } 1739 } 1740 1741 const DataLayout &DL = *AP.TM.getDataLayout(); 1742 unsigned Size = DL.getTypeAllocSize(CDS->getType()); 1743 unsigned EmittedSize = DL.getTypeAllocSize(CDS->getType()->getElementType()) * 1744 CDS->getNumElements(); 1745 if (unsigned Padding = Size - EmittedSize) 1746 AP.OutStreamer.EmitZeros(Padding); 1747 1748} 1749 1750static void emitGlobalConstantArray(const ConstantArray *CA, AsmPrinter &AP) { 1751 // See if we can aggregate some values. Make sure it can be 1752 // represented as a series of bytes of the constant value. 1753 int Value = isRepeatedByteSequence(CA, AP.TM); 1754 1755 if (Value != -1) { 1756 uint64_t Bytes = AP.TM.getDataLayout()->getTypeAllocSize(CA->getType()); 1757 AP.OutStreamer.EmitFill(Bytes, Value); 1758 } 1759 else { 1760 for (unsigned i = 0, e = CA->getNumOperands(); i != e; ++i) 1761 emitGlobalConstantImpl(CA->getOperand(i), AP); 1762 } 1763} 1764 1765static void emitGlobalConstantVector(const ConstantVector *CV, AsmPrinter &AP) { 1766 for (unsigned i = 0, e = CV->getType()->getNumElements(); i != e; ++i) 1767 emitGlobalConstantImpl(CV->getOperand(i), AP); 1768 1769 const DataLayout &DL = *AP.TM.getDataLayout(); 1770 unsigned Size = DL.getTypeAllocSize(CV->getType()); 1771 unsigned EmittedSize = DL.getTypeAllocSize(CV->getType()->getElementType()) * 1772 CV->getType()->getNumElements(); 1773 if (unsigned Padding = Size - EmittedSize) 1774 AP.OutStreamer.EmitZeros(Padding); 1775} 1776 1777static void emitGlobalConstantStruct(const ConstantStruct *CS, AsmPrinter &AP) { 1778 // Print the fields in successive locations. Pad to align if needed! 1779 const DataLayout *DL = AP.TM.getDataLayout(); 1780 unsigned Size = DL->getTypeAllocSize(CS->getType()); 1781 const StructLayout *Layout = DL->getStructLayout(CS->getType()); 1782 uint64_t SizeSoFar = 0; 1783 for (unsigned i = 0, e = CS->getNumOperands(); i != e; ++i) { 1784 const Constant *Field = CS->getOperand(i); 1785 1786 // Check if padding is needed and insert one or more 0s. 1787 uint64_t FieldSize = DL->getTypeAllocSize(Field->getType()); 1788 uint64_t PadSize = ((i == e-1 ? Size : Layout->getElementOffset(i+1)) 1789 - Layout->getElementOffset(i)) - FieldSize; 1790 SizeSoFar += FieldSize + PadSize; 1791 1792 // Now print the actual field value. 1793 emitGlobalConstantImpl(Field, AP); 1794 1795 // Insert padding - this may include padding to increase the size of the 1796 // current field up to the ABI size (if the struct is not packed) as well 1797 // as padding to ensure that the next field starts at the right offset. 1798 AP.OutStreamer.EmitZeros(PadSize); 1799 } 1800 assert(SizeSoFar == Layout->getSizeInBytes() && 1801 "Layout of constant struct may be incorrect!"); 1802} 1803 1804static void emitGlobalConstantFP(const ConstantFP *CFP, AsmPrinter &AP) { 1805 APInt API = CFP->getValueAPF().bitcastToAPInt(); 1806 1807 // First print a comment with what we think the original floating-point value 1808 // should have been. 1809 if (AP.isVerbose()) { 1810 SmallString<8> StrVal; 1811 CFP->getValueAPF().toString(StrVal); 1812 1813 CFP->getType()->print(AP.OutStreamer.GetCommentOS()); 1814 AP.OutStreamer.GetCommentOS() << ' ' << StrVal << '\n'; 1815 } 1816 1817 // Now iterate through the APInt chunks, emitting them in endian-correct 1818 // order, possibly with a smaller chunk at beginning/end (e.g. for x87 80-bit 1819 // floats). 1820 unsigned NumBytes = API.getBitWidth() / 8; 1821 unsigned TrailingBytes = NumBytes % sizeof(uint64_t); 1822 const uint64_t *p = API.getRawData(); 1823 1824 // PPC's long double has odd notions of endianness compared to how LLVM 1825 // handles it: p[0] goes first for *big* endian on PPC. 1826 if (AP.TM.getDataLayout()->isBigEndian() != CFP->getType()->isPPC_FP128Ty()) { 1827 int Chunk = API.getNumWords() - 1; 1828 1829 if (TrailingBytes) 1830 AP.OutStreamer.EmitIntValue(p[Chunk--], TrailingBytes); 1831 1832 for (; Chunk >= 0; --Chunk) 1833 AP.OutStreamer.EmitIntValue(p[Chunk], sizeof(uint64_t)); 1834 } else { 1835 unsigned Chunk; 1836 for (Chunk = 0; Chunk < NumBytes / sizeof(uint64_t); ++Chunk) 1837 AP.OutStreamer.EmitIntValue(p[Chunk], sizeof(uint64_t)); 1838 1839 if (TrailingBytes) 1840 AP.OutStreamer.EmitIntValue(p[Chunk], TrailingBytes); 1841 } 1842 1843 // Emit the tail padding for the long double. 1844 const DataLayout &DL = *AP.TM.getDataLayout(); 1845 AP.OutStreamer.EmitZeros(DL.getTypeAllocSize(CFP->getType()) - 1846 DL.getTypeStoreSize(CFP->getType())); 1847} 1848 1849static void emitGlobalConstantLargeInt(const ConstantInt *CI, AsmPrinter &AP) { 1850 const DataLayout *DL = AP.TM.getDataLayout(); 1851 unsigned BitWidth = CI->getBitWidth(); 1852 1853 // Copy the value as we may massage the layout for constants whose bit width 1854 // is not a multiple of 64-bits. 1855 APInt Realigned(CI->getValue()); 1856 uint64_t ExtraBits = 0; 1857 unsigned ExtraBitsSize = BitWidth & 63; 1858 1859 if (ExtraBitsSize) { 1860 // The bit width of the data is not a multiple of 64-bits. 1861 // The extra bits are expected to be at the end of the chunk of the memory. 1862 // Little endian: 1863 // * Nothing to be done, just record the extra bits to emit. 1864 // Big endian: 1865 // * Record the extra bits to emit. 1866 // * Realign the raw data to emit the chunks of 64-bits. 1867 if (DL->isBigEndian()) { 1868 // Basically the structure of the raw data is a chunk of 64-bits cells: 1869 // 0 1 BitWidth / 64 1870 // [chunk1][chunk2] ... [chunkN]. 1871 // The most significant chunk is chunkN and it should be emitted first. 1872 // However, due to the alignment issue chunkN contains useless bits. 1873 // Realign the chunks so that they contain only useless information: 1874 // ExtraBits 0 1 (BitWidth / 64) - 1 1875 // chu[nk1 chu][nk2 chu] ... [nkN-1 chunkN] 1876 ExtraBits = Realigned.getRawData()[0] & 1877 (((uint64_t)-1) >> (64 - ExtraBitsSize)); 1878 Realigned = Realigned.lshr(ExtraBitsSize); 1879 } else 1880 ExtraBits = Realigned.getRawData()[BitWidth / 64]; 1881 } 1882 1883 // We don't expect assemblers to support integer data directives 1884 // for more than 64 bits, so we emit the data in at most 64-bit 1885 // quantities at a time. 1886 const uint64_t *RawData = Realigned.getRawData(); 1887 for (unsigned i = 0, e = BitWidth / 64; i != e; ++i) { 1888 uint64_t Val = DL->isBigEndian() ? RawData[e - i - 1] : RawData[i]; 1889 AP.OutStreamer.EmitIntValue(Val, 8); 1890 } 1891 1892 if (ExtraBitsSize) { 1893 // Emit the extra bits after the 64-bits chunks. 1894 1895 // Emit a directive that fills the expected size. 1896 uint64_t Size = AP.TM.getDataLayout()->getTypeAllocSize(CI->getType()); 1897 Size -= (BitWidth / 64) * 8; 1898 assert(Size && Size * 8 >= ExtraBitsSize && 1899 (ExtraBits & (((uint64_t)-1) >> (64 - ExtraBitsSize))) 1900 == ExtraBits && "Directive too small for extra bits."); 1901 AP.OutStreamer.EmitIntValue(ExtraBits, Size); 1902 } 1903} 1904 1905static void emitGlobalConstantImpl(const Constant *CV, AsmPrinter &AP) { 1906 const DataLayout *DL = AP.TM.getDataLayout(); 1907 uint64_t Size = DL->getTypeAllocSize(CV->getType()); 1908 if (isa<ConstantAggregateZero>(CV) || isa<UndefValue>(CV)) 1909 return AP.OutStreamer.EmitZeros(Size); 1910 1911 if (const ConstantInt *CI = dyn_cast<ConstantInt>(CV)) { 1912 switch (Size) { 1913 case 1: 1914 case 2: 1915 case 4: 1916 case 8: 1917 if (AP.isVerbose()) 1918 AP.OutStreamer.GetCommentOS() << format("0x%" PRIx64 "\n", 1919 CI->getZExtValue()); 1920 AP.OutStreamer.EmitIntValue(CI->getZExtValue(), Size); 1921 return; 1922 default: 1923 emitGlobalConstantLargeInt(CI, AP); 1924 return; 1925 } 1926 } 1927 1928 if (const ConstantFP *CFP = dyn_cast<ConstantFP>(CV)) 1929 return emitGlobalConstantFP(CFP, AP); 1930 1931 if (isa<ConstantPointerNull>(CV)) { 1932 AP.OutStreamer.EmitIntValue(0, Size); 1933 return; 1934 } 1935 1936 if (const ConstantDataSequential *CDS = dyn_cast<ConstantDataSequential>(CV)) 1937 return emitGlobalConstantDataSequential(CDS, AP); 1938 1939 if (const ConstantArray *CVA = dyn_cast<ConstantArray>(CV)) 1940 return emitGlobalConstantArray(CVA, AP); 1941 1942 if (const ConstantStruct *CVS = dyn_cast<ConstantStruct>(CV)) 1943 return emitGlobalConstantStruct(CVS, AP); 1944 1945 if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(CV)) { 1946 // Look through bitcasts, which might not be able to be MCExpr'ized (e.g. of 1947 // vectors). 1948 if (CE->getOpcode() == Instruction::BitCast) 1949 return emitGlobalConstantImpl(CE->getOperand(0), AP); 1950 1951 if (Size > 8) { 1952 // If the constant expression's size is greater than 64-bits, then we have 1953 // to emit the value in chunks. Try to constant fold the value and emit it 1954 // that way. 1955 Constant *New = ConstantFoldConstantExpression(CE, DL); 1956 if (New && New != CE) 1957 return emitGlobalConstantImpl(New, AP); 1958 } 1959 } 1960 1961 if (const ConstantVector *V = dyn_cast<ConstantVector>(CV)) 1962 return emitGlobalConstantVector(V, AP); 1963 1964 // Otherwise, it must be a ConstantExpr. Lower it to an MCExpr, then emit it 1965 // thread the streamer with EmitValue. 1966 AP.OutStreamer.EmitValue(lowerConstant(CV, AP), Size); 1967} 1968 1969/// EmitGlobalConstant - Print a general LLVM constant to the .s file. 1970void AsmPrinter::EmitGlobalConstant(const Constant *CV) { 1971 uint64_t Size = TM.getDataLayout()->getTypeAllocSize(CV->getType()); 1972 if (Size) 1973 emitGlobalConstantImpl(CV, *this); 1974 else if (MAI->hasSubsectionsViaSymbols()) { 1975 // If the global has zero size, emit a single byte so that two labels don't 1976 // look like they are at the same location. 1977 OutStreamer.EmitIntValue(0, 1); 1978 } 1979} 1980 1981void AsmPrinter::EmitMachineConstantPoolValue(MachineConstantPoolValue *MCPV) { 1982 // Target doesn't support this yet! 1983 llvm_unreachable("Target does not support EmitMachineConstantPoolValue"); 1984} 1985 1986void AsmPrinter::printOffset(int64_t Offset, raw_ostream &OS) const { 1987 if (Offset > 0) 1988 OS << '+' << Offset; 1989 else if (Offset < 0) 1990 OS << Offset; 1991} 1992 1993//===----------------------------------------------------------------------===// 1994// Symbol Lowering Routines. 1995//===----------------------------------------------------------------------===// 1996 1997/// GetTempSymbol - Return the MCSymbol corresponding to the assembler 1998/// temporary label with the specified stem and unique ID. 1999MCSymbol *AsmPrinter::GetTempSymbol(StringRef Name, unsigned ID) const { 2000 return OutContext.GetOrCreateSymbol(Twine(MAI->getPrivateGlobalPrefix()) + 2001 Name + Twine(ID)); 2002} 2003 2004/// GetTempSymbol - Return an assembler temporary label with the specified 2005/// stem. 2006MCSymbol *AsmPrinter::GetTempSymbol(StringRef Name) const { 2007 return OutContext.GetOrCreateSymbol(Twine(MAI->getPrivateGlobalPrefix())+ 2008 Name); 2009} 2010 2011 2012MCSymbol *AsmPrinter::GetBlockAddressSymbol(const BlockAddress *BA) const { 2013 return MMI->getAddrLabelSymbol(BA->getBasicBlock()); 2014} 2015 2016MCSymbol *AsmPrinter::GetBlockAddressSymbol(const BasicBlock *BB) const { 2017 return MMI->getAddrLabelSymbol(BB); 2018} 2019 2020/// GetCPISymbol - Return the symbol for the specified constant pool entry. 2021MCSymbol *AsmPrinter::GetCPISymbol(unsigned CPID) const { 2022 return OutContext.GetOrCreateSymbol 2023 (Twine(MAI->getPrivateGlobalPrefix()) + "CPI" + Twine(getFunctionNumber()) 2024 + "_" + Twine(CPID)); 2025} 2026 2027/// GetJTISymbol - Return the symbol for the specified jump table entry. 2028MCSymbol *AsmPrinter::GetJTISymbol(unsigned JTID, bool isLinkerPrivate) const { 2029 return MF->getJTISymbol(JTID, OutContext, isLinkerPrivate); 2030} 2031 2032/// GetJTSetSymbol - Return the symbol for the specified jump table .set 2033/// FIXME: privatize to AsmPrinter. 2034MCSymbol *AsmPrinter::GetJTSetSymbol(unsigned UID, unsigned MBBID) const { 2035 return OutContext.GetOrCreateSymbol 2036 (Twine(MAI->getPrivateGlobalPrefix()) + Twine(getFunctionNumber()) + "_" + 2037 Twine(UID) + "_set_" + Twine(MBBID)); 2038} 2039 2040/// GetSymbolWithGlobalValueBase - Return the MCSymbol for a symbol with 2041/// global value name as its base, with the specified suffix, and where the 2042/// symbol is forced to have private linkage if ForcePrivate is true. 2043MCSymbol *AsmPrinter::GetSymbolWithGlobalValueBase(const GlobalValue *GV, 2044 StringRef Suffix, 2045 bool ForcePrivate) const { 2046 SmallString<60> NameStr; 2047 Mang->getNameWithPrefix(NameStr, GV, ForcePrivate); 2048 NameStr.append(Suffix.begin(), Suffix.end()); 2049 return OutContext.GetOrCreateSymbol(NameStr.str()); 2050} 2051 2052/// GetExternalSymbolSymbol - Return the MCSymbol for the specified 2053/// ExternalSymbol. 2054MCSymbol *AsmPrinter::GetExternalSymbolSymbol(StringRef Sym) const { 2055 SmallString<60> NameStr; 2056 Mang->getNameWithPrefix(NameStr, Sym); 2057 return OutContext.GetOrCreateSymbol(NameStr.str()); 2058} 2059 2060 2061 2062/// PrintParentLoopComment - Print comments about parent loops of this one. 2063static void PrintParentLoopComment(raw_ostream &OS, const MachineLoop *Loop, 2064 unsigned FunctionNumber) { 2065 if (Loop == 0) return; 2066 PrintParentLoopComment(OS, Loop->getParentLoop(), FunctionNumber); 2067 OS.indent(Loop->getLoopDepth()*2) 2068 << "Parent Loop BB" << FunctionNumber << "_" 2069 << Loop->getHeader()->getNumber() 2070 << " Depth=" << Loop->getLoopDepth() << '\n'; 2071} 2072 2073 2074/// PrintChildLoopComment - Print comments about child loops within 2075/// the loop for this basic block, with nesting. 2076static void PrintChildLoopComment(raw_ostream &OS, const MachineLoop *Loop, 2077 unsigned FunctionNumber) { 2078 // Add child loop information 2079 for (MachineLoop::iterator CL = Loop->begin(), E = Loop->end();CL != E; ++CL){ 2080 OS.indent((*CL)->getLoopDepth()*2) 2081 << "Child Loop BB" << FunctionNumber << "_" 2082 << (*CL)->getHeader()->getNumber() << " Depth " << (*CL)->getLoopDepth() 2083 << '\n'; 2084 PrintChildLoopComment(OS, *CL, FunctionNumber); 2085 } 2086} 2087 2088/// emitBasicBlockLoopComments - Pretty-print comments for basic blocks. 2089static void emitBasicBlockLoopComments(const MachineBasicBlock &MBB, 2090 const MachineLoopInfo *LI, 2091 const AsmPrinter &AP) { 2092 // Add loop depth information 2093 const MachineLoop *Loop = LI->getLoopFor(&MBB); 2094 if (Loop == 0) return; 2095 2096 MachineBasicBlock *Header = Loop->getHeader(); 2097 assert(Header && "No header for loop"); 2098 2099 // If this block is not a loop header, just print out what is the loop header 2100 // and return. 2101 if (Header != &MBB) { 2102 AP.OutStreamer.AddComment(" in Loop: Header=BB" + 2103 Twine(AP.getFunctionNumber())+"_" + 2104 Twine(Loop->getHeader()->getNumber())+ 2105 " Depth="+Twine(Loop->getLoopDepth())); 2106 return; 2107 } 2108 2109 // Otherwise, it is a loop header. Print out information about child and 2110 // parent loops. 2111 raw_ostream &OS = AP.OutStreamer.GetCommentOS(); 2112 2113 PrintParentLoopComment(OS, Loop->getParentLoop(), AP.getFunctionNumber()); 2114 2115 OS << "=>"; 2116 OS.indent(Loop->getLoopDepth()*2-2); 2117 2118 OS << "This "; 2119 if (Loop->empty()) 2120 OS << "Inner "; 2121 OS << "Loop Header: Depth=" + Twine(Loop->getLoopDepth()) << '\n'; 2122 2123 PrintChildLoopComment(OS, Loop, AP.getFunctionNumber()); 2124} 2125 2126 2127/// EmitBasicBlockStart - This method prints the label for the specified 2128/// MachineBasicBlock, an alignment (if present) and a comment describing 2129/// it if appropriate. 2130void AsmPrinter::EmitBasicBlockStart(const MachineBasicBlock *MBB) const { 2131 // Emit an alignment directive for this block, if needed. 2132 if (unsigned Align = MBB->getAlignment()) 2133 EmitAlignment(Align); 2134 2135 // If the block has its address taken, emit any labels that were used to 2136 // reference the block. It is possible that there is more than one label 2137 // here, because multiple LLVM BB's may have been RAUW'd to this block after 2138 // the references were generated. 2139 if (MBB->hasAddressTaken()) { 2140 const BasicBlock *BB = MBB->getBasicBlock(); 2141 if (isVerbose()) 2142 OutStreamer.AddComment("Block address taken"); 2143 2144 std::vector<MCSymbol*> Syms = MMI->getAddrLabelSymbolToEmit(BB); 2145 2146 for (unsigned i = 0, e = Syms.size(); i != e; ++i) 2147 OutStreamer.EmitLabel(Syms[i]); 2148 } 2149 2150 // Print some verbose block comments. 2151 if (isVerbose()) { 2152 if (const BasicBlock *BB = MBB->getBasicBlock()) 2153 if (BB->hasName()) 2154 OutStreamer.AddComment("%" + BB->getName()); 2155 emitBasicBlockLoopComments(*MBB, LI, *this); 2156 } 2157 2158 // Print the main label for the block. 2159 if (MBB->pred_empty() || isBlockOnlyReachableByFallthrough(MBB)) { 2160 if (isVerbose() && OutStreamer.hasRawTextSupport()) { 2161 // NOTE: Want this comment at start of line, don't emit with AddComment. 2162 OutStreamer.EmitRawText(Twine(MAI->getCommentString()) + " BB#" + 2163 Twine(MBB->getNumber()) + ":"); 2164 } 2165 } else { 2166 OutStreamer.EmitLabel(MBB->getSymbol()); 2167 } 2168} 2169 2170void AsmPrinter::EmitVisibility(MCSymbol *Sym, unsigned Visibility, 2171 bool IsDefinition) const { 2172 MCSymbolAttr Attr = MCSA_Invalid; 2173 2174 switch (Visibility) { 2175 default: break; 2176 case GlobalValue::HiddenVisibility: 2177 if (IsDefinition) 2178 Attr = MAI->getHiddenVisibilityAttr(); 2179 else 2180 Attr = MAI->getHiddenDeclarationVisibilityAttr(); 2181 break; 2182 case GlobalValue::ProtectedVisibility: 2183 Attr = MAI->getProtectedVisibilityAttr(); 2184 break; 2185 } 2186 2187 if (Attr != MCSA_Invalid) 2188 OutStreamer.EmitSymbolAttribute(Sym, Attr); 2189} 2190 2191/// isBlockOnlyReachableByFallthough - Return true if the basic block has 2192/// exactly one predecessor and the control transfer mechanism between 2193/// the predecessor and this block is a fall-through. 2194bool AsmPrinter:: 2195isBlockOnlyReachableByFallthrough(const MachineBasicBlock *MBB) const { 2196 // If this is a landing pad, it isn't a fall through. If it has no preds, 2197 // then nothing falls through to it. 2198 if (MBB->isLandingPad() || MBB->pred_empty()) 2199 return false; 2200 2201 // If there isn't exactly one predecessor, it can't be a fall through. 2202 MachineBasicBlock::const_pred_iterator PI = MBB->pred_begin(), PI2 = PI; 2203 ++PI2; 2204 if (PI2 != MBB->pred_end()) 2205 return false; 2206 2207 // The predecessor has to be immediately before this block. 2208 MachineBasicBlock *Pred = *PI; 2209 2210 if (!Pred->isLayoutSuccessor(MBB)) 2211 return false; 2212 2213 // If the block is completely empty, then it definitely does fall through. 2214 if (Pred->empty()) 2215 return true; 2216 2217 // Check the terminators in the previous blocks 2218 for (MachineBasicBlock::iterator II = Pred->getFirstTerminator(), 2219 IE = Pred->end(); II != IE; ++II) { 2220 MachineInstr &MI = *II; 2221 2222 // If it is not a simple branch, we are in a table somewhere. 2223 if (!MI.isBranch() || MI.isIndirectBranch()) 2224 return false; 2225 2226 // If we are the operands of one of the branches, this is not a fall 2227 // through. Note that targets with delay slots will usually bundle 2228 // terminators with the delay slot instruction. 2229 for (ConstMIBundleOperands OP(&MI); OP.isValid(); ++OP) { 2230 if (OP->isJTI()) 2231 return false; 2232 if (OP->isMBB() && OP->getMBB() == MBB) 2233 return false; 2234 } 2235 } 2236 2237 return true; 2238} 2239 2240 2241 2242GCMetadataPrinter *AsmPrinter::GetOrCreateGCPrinter(GCStrategy *S) { 2243 if (!S->usesMetadata()) 2244 return 0; 2245 2246 gcp_map_type &GCMap = getGCMap(GCMetadataPrinters); 2247 gcp_map_type::iterator GCPI = GCMap.find(S); 2248 if (GCPI != GCMap.end()) 2249 return GCPI->second; 2250 2251 const char *Name = S->getName().c_str(); 2252 2253 for (GCMetadataPrinterRegistry::iterator 2254 I = GCMetadataPrinterRegistry::begin(), 2255 E = GCMetadataPrinterRegistry::end(); I != E; ++I) 2256 if (strcmp(Name, I->getName()) == 0) { 2257 GCMetadataPrinter *GMP = I->instantiate(); 2258 GMP->S = S; 2259 GCMap.insert(std::make_pair(S, GMP)); 2260 return GMP; 2261 } 2262 2263 report_fatal_error("no GCMetadataPrinter registered for GC: " + Twine(Name)); 2264} 2265