AsmPrinter.cpp revision f2548caaa8b290aa598bf49c27dff72f7751ba5c
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/Module.h" 19#include "llvm/CodeGen/GCMetadataPrinter.h" 20#include "llvm/CodeGen/MachineConstantPool.h" 21#include "llvm/CodeGen/MachineFrameInfo.h" 22#include "llvm/CodeGen/MachineFunction.h" 23#include "llvm/CodeGen/MachineJumpTableInfo.h" 24#include "llvm/CodeGen/MachineLoopInfo.h" 25#include "llvm/CodeGen/MachineModuleInfo.h" 26#include "llvm/Analysis/ConstantFolding.h" 27#include "llvm/Analysis/DebugInfo.h" 28#include "llvm/MC/MCAsmInfo.h" 29#include "llvm/MC/MCContext.h" 30#include "llvm/MC/MCExpr.h" 31#include "llvm/MC/MCInst.h" 32#include "llvm/MC/MCSection.h" 33#include "llvm/MC/MCStreamer.h" 34#include "llvm/MC/MCSymbol.h" 35#include "llvm/Target/Mangler.h" 36#include "llvm/Target/TargetData.h" 37#include "llvm/Target/TargetInstrInfo.h" 38#include "llvm/Target/TargetLowering.h" 39#include "llvm/Target/TargetLoweringObjectFile.h" 40#include "llvm/Target/TargetRegisterInfo.h" 41#include "llvm/ADT/SmallString.h" 42#include "llvm/ADT/Statistic.h" 43#include "llvm/Support/ErrorHandling.h" 44#include "llvm/Support/Format.h" 45#include "llvm/Support/Timer.h" 46using namespace llvm; 47 48static const char *DWARFGroupName = "DWARF Emission"; 49static const char *DbgTimerName = "DWARF Debug Writer"; 50static const char *EHTimerName = "DWARF Exception Writer"; 51 52STATISTIC(EmittedInsts, "Number of machine instrs printed"); 53 54char AsmPrinter::ID = 0; 55 56typedef DenseMap<GCStrategy*,GCMetadataPrinter*> gcp_map_type; 57static gcp_map_type &getGCMap(void *&P) { 58 if (P == 0) 59 P = new gcp_map_type(); 60 return *(gcp_map_type*)P; 61} 62 63 64AsmPrinter::AsmPrinter(TargetMachine &tm, MCStreamer &Streamer) 65 : MachineFunctionPass(&ID), 66 TM(tm), MAI(tm.getMCAsmInfo()), 67 OutContext(Streamer.getContext()), 68 OutStreamer(Streamer), 69 LastMI(0), LastFn(0), Counter(~0U), SetCounter(0) { 70 DD = 0; DE = 0; MMI = 0; LI = 0; 71 GCMetadataPrinters = 0; 72 VerboseAsm = Streamer.isVerboseAsm(); 73} 74 75AsmPrinter::~AsmPrinter() { 76 assert(DD == 0 && DE == 0 && "Debug/EH info didn't get finalized"); 77 78 if (GCMetadataPrinters != 0) { 79 gcp_map_type &GCMap = getGCMap(GCMetadataPrinters); 80 81 for (gcp_map_type::iterator I = GCMap.begin(), E = GCMap.end(); I != E; ++I) 82 delete I->second; 83 delete &GCMap; 84 GCMetadataPrinters = 0; 85 } 86 87 delete &OutStreamer; 88} 89 90/// getFunctionNumber - Return a unique ID for the current function. 91/// 92unsigned AsmPrinter::getFunctionNumber() const { 93 return MF->getFunctionNumber(); 94} 95 96TargetLoweringObjectFile &AsmPrinter::getObjFileLowering() const { 97 return TM.getTargetLowering()->getObjFileLowering(); 98} 99 100 101/// getTargetData - Return information about data layout. 102const TargetData &AsmPrinter::getTargetData() const { 103 return *TM.getTargetData(); 104} 105 106/// getCurrentSection() - Return the current section we are emitting to. 107const MCSection *AsmPrinter::getCurrentSection() const { 108 return OutStreamer.getCurrentSection(); 109} 110 111 112 113void AsmPrinter::getAnalysisUsage(AnalysisUsage &AU) const { 114 AU.setPreservesAll(); 115 MachineFunctionPass::getAnalysisUsage(AU); 116 AU.addRequired<MachineModuleInfo>(); 117 AU.addRequired<GCModuleInfo>(); 118 if (isVerbose()) 119 AU.addRequired<MachineLoopInfo>(); 120} 121 122bool AsmPrinter::doInitialization(Module &M) { 123 MMI = getAnalysisIfAvailable<MachineModuleInfo>(); 124 MMI->AnalyzeModule(M); 125 126 // Initialize TargetLoweringObjectFile. 127 const_cast<TargetLoweringObjectFile&>(getObjFileLowering()) 128 .Initialize(OutContext, TM); 129 130 Mang = new Mangler(OutContext, *TM.getTargetData()); 131 132 // Allow the target to emit any magic that it wants at the start of the file. 133 EmitStartOfAsmFile(M); 134 135 // Very minimal debug info. It is ignored if we emit actual debug info. If we 136 // don't, this at least helps the user find where a global came from. 137 if (MAI->hasSingleParameterDotFile()) { 138 // .file "foo.c" 139 OutStreamer.EmitFileDirective(M.getModuleIdentifier()); 140 } 141 142 GCModuleInfo *MI = getAnalysisIfAvailable<GCModuleInfo>(); 143 assert(MI && "AsmPrinter didn't require GCModuleInfo?"); 144 for (GCModuleInfo::iterator I = MI->begin(), E = MI->end(); I != E; ++I) 145 if (GCMetadataPrinter *MP = GetOrCreateGCPrinter(*I)) 146 MP->beginAssembly(*this); 147 148 // Emit module-level inline asm if it exists. 149 if (!M.getModuleInlineAsm().empty()) { 150 OutStreamer.AddComment("Start of file scope inline assembly"); 151 OutStreamer.AddBlankLine(); 152 EmitInlineAsm(M.getModuleInlineAsm(), 0/*no loc cookie*/); 153 OutStreamer.AddComment("End of file scope inline assembly"); 154 OutStreamer.AddBlankLine(); 155 } 156 157 if (MAI->doesSupportDebugInformation()) 158 DD = new DwarfDebug(this, &M); 159 160 if (MAI->doesSupportExceptionHandling()) 161 DE = new DwarfException(this); 162 163 return false; 164} 165 166void AsmPrinter::EmitLinkage(unsigned Linkage, MCSymbol *GVSym) const { 167 switch ((GlobalValue::LinkageTypes)Linkage) { 168 case GlobalValue::CommonLinkage: 169 case GlobalValue::LinkOnceAnyLinkage: 170 case GlobalValue::LinkOnceODRLinkage: 171 case GlobalValue::WeakAnyLinkage: 172 case GlobalValue::WeakODRLinkage: 173 case GlobalValue::LinkerPrivateLinkage: 174 if (MAI->getWeakDefDirective() != 0) { 175 // .globl _foo 176 OutStreamer.EmitSymbolAttribute(GVSym, MCSA_Global); 177 // .weak_definition _foo 178 OutStreamer.EmitSymbolAttribute(GVSym, MCSA_WeakDefinition); 179 } else if (const char *LinkOnce = MAI->getLinkOnceDirective()) { 180 // .globl _foo 181 OutStreamer.EmitSymbolAttribute(GVSym, MCSA_Global); 182 // FIXME: linkonce should be a section attribute, handled by COFF Section 183 // assignment. 184 // http://sourceware.org/binutils/docs-2.20/as/Linkonce.html#Linkonce 185 // .linkonce discard 186 // FIXME: It would be nice to use .linkonce samesize for non-common 187 // globals. 188 OutStreamer.EmitRawText(StringRef(LinkOnce)); 189 } else { 190 // .weak _foo 191 OutStreamer.EmitSymbolAttribute(GVSym, MCSA_Weak); 192 } 193 break; 194 case GlobalValue::DLLExportLinkage: 195 case GlobalValue::AppendingLinkage: 196 // FIXME: appending linkage variables should go into a section of 197 // their name or something. For now, just emit them as external. 198 case GlobalValue::ExternalLinkage: 199 // If external or appending, declare as a global symbol. 200 // .globl _foo 201 OutStreamer.EmitSymbolAttribute(GVSym, MCSA_Global); 202 break; 203 case GlobalValue::PrivateLinkage: 204 case GlobalValue::InternalLinkage: 205 break; 206 default: 207 llvm_unreachable("Unknown linkage type!"); 208 } 209} 210 211 212/// EmitGlobalVariable - Emit the specified global variable to the .s file. 213void AsmPrinter::EmitGlobalVariable(const GlobalVariable *GV) { 214 if (!GV->hasInitializer()) // External globals require no code. 215 return; 216 217 // Check to see if this is a special global used by LLVM, if so, emit it. 218 if (EmitSpecialLLVMGlobal(GV)) 219 return; 220 221 MCSymbol *GVSym = Mang->getSymbol(GV); 222 EmitVisibility(GVSym, GV->getVisibility()); 223 224 if (MAI->hasDotTypeDotSizeDirective()) 225 OutStreamer.EmitSymbolAttribute(GVSym, MCSA_ELF_TypeObject); 226 227 SectionKind GVKind = TargetLoweringObjectFile::getKindForGlobal(GV, TM); 228 229 const TargetData *TD = TM.getTargetData(); 230 unsigned Size = TD->getTypeAllocSize(GV->getType()->getElementType()); 231 unsigned AlignLog = TD->getPreferredAlignmentLog(GV); 232 233 // Handle common and BSS local symbols (.lcomm). 234 if (GVKind.isCommon() || GVKind.isBSSLocal()) { 235 if (Size == 0) Size = 1; // .comm Foo, 0 is undefined, avoid it. 236 237 if (isVerbose()) { 238 WriteAsOperand(OutStreamer.GetCommentOS(), GV, 239 /*PrintType=*/false, GV->getParent()); 240 OutStreamer.GetCommentOS() << '\n'; 241 } 242 243 // Handle common symbols. 244 if (GVKind.isCommon()) { 245 // .comm _foo, 42, 4 246 OutStreamer.EmitCommonSymbol(GVSym, Size, 1 << AlignLog); 247 return; 248 } 249 250 // Handle local BSS symbols. 251 if (MAI->hasMachoZeroFillDirective()) { 252 const MCSection *TheSection = 253 getObjFileLowering().SectionForGlobal(GV, GVKind, Mang, TM); 254 // .zerofill __DATA, __bss, _foo, 400, 5 255 OutStreamer.EmitZerofill(TheSection, GVSym, Size, 1 << AlignLog); 256 return; 257 } 258 259 if (MAI->hasLCOMMDirective()) { 260 // .lcomm _foo, 42 261 OutStreamer.EmitLocalCommonSymbol(GVSym, Size); 262 return; 263 } 264 265 // .local _foo 266 OutStreamer.EmitSymbolAttribute(GVSym, MCSA_Local); 267 // .comm _foo, 42, 4 268 OutStreamer.EmitCommonSymbol(GVSym, Size, 1 << AlignLog); 269 return; 270 } 271 272 const MCSection *TheSection = 273 getObjFileLowering().SectionForGlobal(GV, GVKind, Mang, TM); 274 275 // Handle the zerofill directive on darwin, which is a special form of BSS 276 // emission. 277 if (GVKind.isBSSExtern() && MAI->hasMachoZeroFillDirective()) { 278 // .globl _foo 279 OutStreamer.EmitSymbolAttribute(GVSym, MCSA_Global); 280 // .zerofill __DATA, __common, _foo, 400, 5 281 OutStreamer.EmitZerofill(TheSection, GVSym, Size, 1 << AlignLog); 282 return; 283 } 284 285 OutStreamer.SwitchSection(TheSection); 286 287 EmitLinkage(GV->getLinkage(), GVSym); 288 EmitAlignment(AlignLog, GV); 289 290 if (isVerbose()) { 291 WriteAsOperand(OutStreamer.GetCommentOS(), GV, 292 /*PrintType=*/false, GV->getParent()); 293 OutStreamer.GetCommentOS() << '\n'; 294 } 295 OutStreamer.EmitLabel(GVSym); 296 297 EmitGlobalConstant(GV->getInitializer()); 298 299 if (MAI->hasDotTypeDotSizeDirective()) 300 // .size foo, 42 301 OutStreamer.EmitELFSize(GVSym, MCConstantExpr::Create(Size, OutContext)); 302 303 OutStreamer.AddBlankLine(); 304} 305 306/// EmitFunctionHeader - This method emits the header for the current 307/// function. 308void AsmPrinter::EmitFunctionHeader() { 309 // Print out constants referenced by the function 310 EmitConstantPool(); 311 312 // Print the 'header' of function. 313 const Function *F = MF->getFunction(); 314 315 OutStreamer.SwitchSection(getObjFileLowering().SectionForGlobal(F, Mang, TM)); 316 EmitVisibility(CurrentFnSym, F->getVisibility()); 317 318 EmitLinkage(F->getLinkage(), CurrentFnSym); 319 EmitAlignment(MF->getAlignment(), F); 320 321 if (MAI->hasDotTypeDotSizeDirective()) 322 OutStreamer.EmitSymbolAttribute(CurrentFnSym, MCSA_ELF_TypeFunction); 323 324 if (isVerbose()) { 325 WriteAsOperand(OutStreamer.GetCommentOS(), F, 326 /*PrintType=*/false, F->getParent()); 327 OutStreamer.GetCommentOS() << '\n'; 328 } 329 330 // Emit the CurrentFnSym. This is a virtual function to allow targets to 331 // do their wild and crazy things as required. 332 EmitFunctionEntryLabel(); 333 334 // If the function had address-taken blocks that got deleted, then we have 335 // references to the dangling symbols. Emit them at the start of the function 336 // so that we don't get references to undefined symbols. 337 std::vector<MCSymbol*> DeadBlockSyms; 338 MMI->takeDeletedSymbolsForFunction(F, DeadBlockSyms); 339 for (unsigned i = 0, e = DeadBlockSyms.size(); i != e; ++i) { 340 OutStreamer.AddComment("Address taken block that was later removed"); 341 OutStreamer.EmitLabel(DeadBlockSyms[i]); 342 } 343 344 // Add some workaround for linkonce linkage on Cygwin\MinGW. 345 if (MAI->getLinkOnceDirective() != 0 && 346 (F->hasLinkOnceLinkage() || F->hasWeakLinkage())) { 347 // FIXME: What is this? 348 MCSymbol *FakeStub = 349 OutContext.GetOrCreateSymbol(Twine("Lllvm$workaround$fake$stub$")+ 350 CurrentFnSym->getName()); 351 OutStreamer.EmitLabel(FakeStub); 352 } 353 354 // Emit pre-function debug and/or EH information. 355 if (DE) { 356 if (TimePassesIsEnabled) { 357 NamedRegionTimer T(EHTimerName, DWARFGroupName); 358 DE->BeginFunction(MF); 359 } else { 360 DE->BeginFunction(MF); 361 } 362 } 363 if (DD) { 364 if (TimePassesIsEnabled) { 365 NamedRegionTimer T(DbgTimerName, DWARFGroupName); 366 DD->beginFunction(MF); 367 } else { 368 DD->beginFunction(MF); 369 } 370 } 371} 372 373/// EmitFunctionEntryLabel - Emit the label that is the entrypoint for the 374/// function. This can be overridden by targets as required to do custom stuff. 375void AsmPrinter::EmitFunctionEntryLabel() { 376 OutStreamer.EmitLabel(CurrentFnSym); 377} 378 379 380/// EmitComments - Pretty-print comments for instructions. 381static void EmitComments(const MachineInstr &MI, raw_ostream &CommentOS) { 382 const MachineFunction *MF = MI.getParent()->getParent(); 383 const TargetMachine &TM = MF->getTarget(); 384 385 DebugLoc DL = MI.getDebugLoc(); 386 if (!DL.isUnknown()) { // Print source line info. 387 DIScope Scope(DL.getScope(MF->getFunction()->getContext())); 388 // Omit the directory, because it's likely to be long and uninteresting. 389 if (Scope.Verify()) 390 CommentOS << Scope.getFilename(); 391 else 392 CommentOS << "<unknown>"; 393 CommentOS << ':' << DL.getLine(); 394 if (DL.getCol() != 0) 395 CommentOS << ':' << DL.getCol(); 396 CommentOS << '\n'; 397 } 398 399 // Check for spills and reloads 400 int FI; 401 402 const MachineFrameInfo *FrameInfo = MF->getFrameInfo(); 403 404 // We assume a single instruction only has a spill or reload, not 405 // both. 406 const MachineMemOperand *MMO; 407 if (TM.getInstrInfo()->isLoadFromStackSlotPostFE(&MI, FI)) { 408 if (FrameInfo->isSpillSlotObjectIndex(FI)) { 409 MMO = *MI.memoperands_begin(); 410 CommentOS << MMO->getSize() << "-byte Reload\n"; 411 } 412 } else if (TM.getInstrInfo()->hasLoadFromStackSlot(&MI, MMO, FI)) { 413 if (FrameInfo->isSpillSlotObjectIndex(FI)) 414 CommentOS << MMO->getSize() << "-byte Folded Reload\n"; 415 } else if (TM.getInstrInfo()->isStoreToStackSlotPostFE(&MI, FI)) { 416 if (FrameInfo->isSpillSlotObjectIndex(FI)) { 417 MMO = *MI.memoperands_begin(); 418 CommentOS << MMO->getSize() << "-byte Spill\n"; 419 } 420 } else if (TM.getInstrInfo()->hasStoreToStackSlot(&MI, MMO, FI)) { 421 if (FrameInfo->isSpillSlotObjectIndex(FI)) 422 CommentOS << MMO->getSize() << "-byte Folded Spill\n"; 423 } 424 425 // Check for spill-induced copies 426 unsigned SrcReg, DstReg, SrcSubIdx, DstSubIdx; 427 if (TM.getInstrInfo()->isMoveInstr(MI, SrcReg, DstReg, 428 SrcSubIdx, DstSubIdx)) { 429 if (MI.getAsmPrinterFlag(MachineInstr::ReloadReuse)) 430 CommentOS << " Reload Reuse\n"; 431 } 432} 433 434/// EmitImplicitDef - This method emits the specified machine instruction 435/// that is an implicit def. 436static void EmitImplicitDef(const MachineInstr *MI, AsmPrinter &AP) { 437 unsigned RegNo = MI->getOperand(0).getReg(); 438 AP.OutStreamer.AddComment(Twine("implicit-def: ") + 439 AP.TM.getRegisterInfo()->getName(RegNo)); 440 AP.OutStreamer.AddBlankLine(); 441} 442 443static void EmitKill(const MachineInstr *MI, AsmPrinter &AP) { 444 std::string Str = "kill:"; 445 for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) { 446 const MachineOperand &Op = MI->getOperand(i); 447 assert(Op.isReg() && "KILL instruction must have only register operands"); 448 Str += ' '; 449 Str += AP.TM.getRegisterInfo()->getName(Op.getReg()); 450 Str += (Op.isDef() ? "<def>" : "<kill>"); 451 } 452 AP.OutStreamer.AddComment(Str); 453 AP.OutStreamer.AddBlankLine(); 454} 455 456/// EmitDebugValueComment - This method handles the target-independent form 457/// of DBG_VALUE, returning true if it was able to do so. A false return 458/// means the target will need to handle MI in EmitInstruction. 459static bool EmitDebugValueComment(const MachineInstr *MI, AsmPrinter &AP) { 460 // This code handles only the 3-operand target-independent form. 461 if (MI->getNumOperands() != 3) 462 return false; 463 464 SmallString<128> Str; 465 raw_svector_ostream OS(Str); 466 OS << '\t' << AP.MAI->getCommentString() << "DEBUG_VALUE: "; 467 468 // cast away const; DIetc do not take const operands for some reason. 469 DIVariable V(const_cast<MDNode*>(MI->getOperand(2).getMetadata())); 470 OS << V.getName() << " <- "; 471 472 // Register or immediate value. Register 0 means undef. 473 if (MI->getOperand(0).isFPImm()) { 474 APFloat APF = APFloat(MI->getOperand(0).getFPImm()->getValueAPF()); 475 if (MI->getOperand(0).getFPImm()->getType()->isFloatTy()) { 476 OS << (double)APF.convertToFloat(); 477 } else if (MI->getOperand(0).getFPImm()->getType()->isDoubleTy()) { 478 OS << APF.convertToDouble(); 479 } else { 480 // There is no good way to print long double. Convert a copy to 481 // double. Ah well, it's only a comment. 482 bool ignored; 483 APF.convert(APFloat::IEEEdouble, APFloat::rmNearestTiesToEven, 484 &ignored); 485 OS << "(long double) " << APF.convertToDouble(); 486 } 487 } else if (MI->getOperand(0).isImm()) { 488 OS << MI->getOperand(0).getImm(); 489 } else { 490 assert(MI->getOperand(0).isReg() && "Unknown operand type"); 491 if (MI->getOperand(0).getReg() == 0) { 492 // Suppress offset, it is not meaningful here. 493 OS << "undef"; 494 // NOTE: Want this comment at start of line, don't emit with AddComment. 495 AP.OutStreamer.EmitRawText(OS.str()); 496 return true; 497 } 498 OS << AP.TM.getRegisterInfo()->getName(MI->getOperand(0).getReg()); 499 } 500 501 OS << '+' << MI->getOperand(1).getImm(); 502 // NOTE: Want this comment at start of line, don't emit with AddComment. 503 AP.OutStreamer.EmitRawText(OS.str()); 504 return true; 505} 506 507/// EmitFunctionBody - This method emits the body and trailer for a 508/// function. 509void AsmPrinter::EmitFunctionBody() { 510 // Emit target-specific gunk before the function body. 511 EmitFunctionBodyStart(); 512 513 bool ShouldPrintDebugScopes = DD && MMI->hasDebugInfo(); 514 515 // Print out code for the function. 516 bool HasAnyRealCode = false; 517 for (MachineFunction::const_iterator I = MF->begin(), E = MF->end(); 518 I != E; ++I) { 519 // Print a label for the basic block. 520 EmitBasicBlockStart(I); 521 for (MachineBasicBlock::const_iterator II = I->begin(), IE = I->end(); 522 II != IE; ++II) { 523 // Print the assembly for the instruction. 524 if (!II->isLabel()) 525 HasAnyRealCode = true; 526 527 ++EmittedInsts; 528 529 if (ShouldPrintDebugScopes) { 530 if (TimePassesIsEnabled) { 531 NamedRegionTimer T(DbgTimerName, DWARFGroupName); 532 DD->beginScope(II); 533 } else { 534 DD->beginScope(II); 535 } 536 } 537 538 if (isVerbose()) 539 EmitComments(*II, OutStreamer.GetCommentOS()); 540 541 switch (II->getOpcode()) { 542 case TargetOpcode::DBG_LABEL: 543 case TargetOpcode::EH_LABEL: 544 case TargetOpcode::GC_LABEL: 545 OutStreamer.EmitLabel(II->getOperand(0).getMCSymbol()); 546 break; 547 case TargetOpcode::INLINEASM: 548 EmitInlineAsm(II); 549 break; 550 case TargetOpcode::DBG_VALUE: 551 if (isVerbose()) { 552 if (!EmitDebugValueComment(II, *this)) 553 EmitInstruction(II); 554 } 555 break; 556 case TargetOpcode::IMPLICIT_DEF: 557 if (isVerbose()) EmitImplicitDef(II, *this); 558 break; 559 case TargetOpcode::KILL: 560 if (isVerbose()) EmitKill(II, *this); 561 break; 562 default: 563 EmitInstruction(II); 564 break; 565 } 566 567 if (ShouldPrintDebugScopes) { 568 if (TimePassesIsEnabled) { 569 NamedRegionTimer T(DbgTimerName, DWARFGroupName); 570 DD->endScope(II); 571 } else { 572 DD->endScope(II); 573 } 574 } 575 } 576 } 577 578 // If the function is empty and the object file uses .subsections_via_symbols, 579 // then we need to emit *something* to the function body to prevent the 580 // labels from collapsing together. Just emit a 0 byte. 581 if (MAI->hasSubsectionsViaSymbols() && !HasAnyRealCode) 582 OutStreamer.EmitIntValue(0, 1, 0/*addrspace*/); 583 584 // Emit target-specific gunk after the function body. 585 EmitFunctionBodyEnd(); 586 587 // If the target wants a .size directive for the size of the function, emit 588 // it. 589 if (MAI->hasDotTypeDotSizeDirective()) { 590 // Create a symbol for the end of function, so we can get the size as 591 // difference between the function label and the temp label. 592 MCSymbol *FnEndLabel = OutContext.CreateTempSymbol(); 593 OutStreamer.EmitLabel(FnEndLabel); 594 595 const MCExpr *SizeExp = 596 MCBinaryExpr::CreateSub(MCSymbolRefExpr::Create(FnEndLabel, OutContext), 597 MCSymbolRefExpr::Create(CurrentFnSym, OutContext), 598 OutContext); 599 OutStreamer.EmitELFSize(CurrentFnSym, SizeExp); 600 } 601 602 // Emit post-function debug information. 603 if (DD) { 604 if (TimePassesIsEnabled) { 605 NamedRegionTimer T(DbgTimerName, DWARFGroupName); 606 DD->endFunction(MF); 607 } else { 608 DD->endFunction(MF); 609 } 610 } 611 if (DE) { 612 if (TimePassesIsEnabled) { 613 NamedRegionTimer T(EHTimerName, DWARFGroupName); 614 DE->EndFunction(); 615 } else { 616 DE->EndFunction(); 617 } 618 } 619 MMI->EndFunction(); 620 621 // Print out jump tables referenced by the function. 622 EmitJumpTableInfo(); 623 624 OutStreamer.AddBlankLine(); 625} 626 627 628bool AsmPrinter::doFinalization(Module &M) { 629 // Emit global variables. 630 for (Module::const_global_iterator I = M.global_begin(), E = M.global_end(); 631 I != E; ++I) 632 EmitGlobalVariable(I); 633 634 // Finalize debug and EH information. 635 if (DE) { 636 if (TimePassesIsEnabled) { 637 NamedRegionTimer T(EHTimerName, DWARFGroupName); 638 DE->EndModule(); 639 } else { 640 DE->EndModule(); 641 } 642 delete DE; DE = 0; 643 } 644 if (DD) { 645 if (TimePassesIsEnabled) { 646 NamedRegionTimer T(DbgTimerName, DWARFGroupName); 647 DD->endModule(); 648 } else { 649 DD->endModule(); 650 } 651 delete DD; DD = 0; 652 } 653 654 // If the target wants to know about weak references, print them all. 655 if (MAI->getWeakRefDirective()) { 656 // FIXME: This is not lazy, it would be nice to only print weak references 657 // to stuff that is actually used. Note that doing so would require targets 658 // to notice uses in operands (due to constant exprs etc). This should 659 // happen with the MC stuff eventually. 660 661 // Print out module-level global variables here. 662 for (Module::const_global_iterator I = M.global_begin(), E = M.global_end(); 663 I != E; ++I) { 664 if (!I->hasExternalWeakLinkage()) continue; 665 OutStreamer.EmitSymbolAttribute(Mang->getSymbol(I), MCSA_WeakReference); 666 } 667 668 for (Module::const_iterator I = M.begin(), E = M.end(); I != E; ++I) { 669 if (!I->hasExternalWeakLinkage()) continue; 670 OutStreamer.EmitSymbolAttribute(Mang->getSymbol(I), MCSA_WeakReference); 671 } 672 } 673 674 if (MAI->hasSetDirective()) { 675 OutStreamer.AddBlankLine(); 676 for (Module::const_alias_iterator I = M.alias_begin(), E = M.alias_end(); 677 I != E; ++I) { 678 MCSymbol *Name = Mang->getSymbol(I); 679 680 const GlobalValue *GV = cast<GlobalValue>(I->getAliasedGlobal()); 681 MCSymbol *Target = Mang->getSymbol(GV); 682 683 if (I->hasExternalLinkage() || !MAI->getWeakRefDirective()) 684 OutStreamer.EmitSymbolAttribute(Name, MCSA_Global); 685 else if (I->hasWeakLinkage()) 686 OutStreamer.EmitSymbolAttribute(Name, MCSA_WeakReference); 687 else 688 assert(I->hasLocalLinkage() && "Invalid alias linkage"); 689 690 EmitVisibility(Name, I->getVisibility()); 691 692 // Emit the directives as assignments aka .set: 693 OutStreamer.EmitAssignment(Name, 694 MCSymbolRefExpr::Create(Target, OutContext)); 695 } 696 } 697 698 GCModuleInfo *MI = getAnalysisIfAvailable<GCModuleInfo>(); 699 assert(MI && "AsmPrinter didn't require GCModuleInfo?"); 700 for (GCModuleInfo::iterator I = MI->end(), E = MI->begin(); I != E; ) 701 if (GCMetadataPrinter *MP = GetOrCreateGCPrinter(*--I)) 702 MP->finishAssembly(*this); 703 704 // If we don't have any trampolines, then we don't require stack memory 705 // to be executable. Some targets have a directive to declare this. 706 Function *InitTrampolineIntrinsic = M.getFunction("llvm.init.trampoline"); 707 if (!InitTrampolineIntrinsic || InitTrampolineIntrinsic->use_empty()) 708 if (const MCSection *S = MAI->getNonexecutableStackSection(OutContext)) 709 OutStreamer.SwitchSection(S); 710 711 // Allow the target to emit any magic that it wants at the end of the file, 712 // after everything else has gone out. 713 EmitEndOfAsmFile(M); 714 715 delete Mang; Mang = 0; 716 MMI = 0; 717 718 OutStreamer.Finish(); 719 return false; 720} 721 722void AsmPrinter::SetupMachineFunction(MachineFunction &MF) { 723 this->MF = &MF; 724 // Get the function symbol. 725 CurrentFnSym = Mang->getSymbol(MF.getFunction()); 726 727 if (isVerbose()) 728 LI = &getAnalysis<MachineLoopInfo>(); 729} 730 731namespace { 732 // SectionCPs - Keep track the alignment, constpool entries per Section. 733 struct SectionCPs { 734 const MCSection *S; 735 unsigned Alignment; 736 SmallVector<unsigned, 4> CPEs; 737 SectionCPs(const MCSection *s, unsigned a) : S(s), Alignment(a) {} 738 }; 739} 740 741/// EmitConstantPool - Print to the current output stream assembly 742/// representations of the constants in the constant pool MCP. This is 743/// used to print out constants which have been "spilled to memory" by 744/// the code generator. 745/// 746void AsmPrinter::EmitConstantPool() { 747 const MachineConstantPool *MCP = MF->getConstantPool(); 748 const std::vector<MachineConstantPoolEntry> &CP = MCP->getConstants(); 749 if (CP.empty()) return; 750 751 // Calculate sections for constant pool entries. We collect entries to go into 752 // the same section together to reduce amount of section switch statements. 753 SmallVector<SectionCPs, 4> CPSections; 754 for (unsigned i = 0, e = CP.size(); i != e; ++i) { 755 const MachineConstantPoolEntry &CPE = CP[i]; 756 unsigned Align = CPE.getAlignment(); 757 758 SectionKind Kind; 759 switch (CPE.getRelocationInfo()) { 760 default: llvm_unreachable("Unknown section kind"); 761 case 2: Kind = SectionKind::getReadOnlyWithRel(); break; 762 case 1: 763 Kind = SectionKind::getReadOnlyWithRelLocal(); 764 break; 765 case 0: 766 switch (TM.getTargetData()->getTypeAllocSize(CPE.getType())) { 767 case 4: Kind = SectionKind::getMergeableConst4(); break; 768 case 8: Kind = SectionKind::getMergeableConst8(); break; 769 case 16: Kind = SectionKind::getMergeableConst16();break; 770 default: Kind = SectionKind::getMergeableConst(); break; 771 } 772 } 773 774 const MCSection *S = getObjFileLowering().getSectionForConstant(Kind); 775 776 // The number of sections are small, just do a linear search from the 777 // last section to the first. 778 bool Found = false; 779 unsigned SecIdx = CPSections.size(); 780 while (SecIdx != 0) { 781 if (CPSections[--SecIdx].S == S) { 782 Found = true; 783 break; 784 } 785 } 786 if (!Found) { 787 SecIdx = CPSections.size(); 788 CPSections.push_back(SectionCPs(S, Align)); 789 } 790 791 if (Align > CPSections[SecIdx].Alignment) 792 CPSections[SecIdx].Alignment = Align; 793 CPSections[SecIdx].CPEs.push_back(i); 794 } 795 796 // Now print stuff into the calculated sections. 797 for (unsigned i = 0, e = CPSections.size(); i != e; ++i) { 798 OutStreamer.SwitchSection(CPSections[i].S); 799 EmitAlignment(Log2_32(CPSections[i].Alignment)); 800 801 unsigned Offset = 0; 802 for (unsigned j = 0, ee = CPSections[i].CPEs.size(); j != ee; ++j) { 803 unsigned CPI = CPSections[i].CPEs[j]; 804 MachineConstantPoolEntry CPE = CP[CPI]; 805 806 // Emit inter-object padding for alignment. 807 unsigned AlignMask = CPE.getAlignment() - 1; 808 unsigned NewOffset = (Offset + AlignMask) & ~AlignMask; 809 OutStreamer.EmitFill(NewOffset - Offset, 0/*fillval*/, 0/*addrspace*/); 810 811 const Type *Ty = CPE.getType(); 812 Offset = NewOffset + TM.getTargetData()->getTypeAllocSize(Ty); 813 814 // Emit the label with a comment on it. 815 if (isVerbose()) { 816 OutStreamer.GetCommentOS() << "constant pool "; 817 WriteTypeSymbolic(OutStreamer.GetCommentOS(), CPE.getType(), 818 MF->getFunction()->getParent()); 819 OutStreamer.GetCommentOS() << '\n'; 820 } 821 OutStreamer.EmitLabel(GetCPISymbol(CPI)); 822 823 if (CPE.isMachineConstantPoolEntry()) 824 EmitMachineConstantPoolValue(CPE.Val.MachineCPVal); 825 else 826 EmitGlobalConstant(CPE.Val.ConstVal); 827 } 828 } 829} 830 831/// EmitJumpTableInfo - Print assembly representations of the jump tables used 832/// by the current function to the current output stream. 833/// 834void AsmPrinter::EmitJumpTableInfo() { 835 const MachineJumpTableInfo *MJTI = MF->getJumpTableInfo(); 836 if (MJTI == 0) return; 837 if (MJTI->getEntryKind() == MachineJumpTableInfo::EK_Inline) return; 838 const std::vector<MachineJumpTableEntry> &JT = MJTI->getJumpTables(); 839 if (JT.empty()) return; 840 841 // Pick the directive to use to print the jump table entries, and switch to 842 // the appropriate section. 843 const Function *F = MF->getFunction(); 844 bool JTInDiffSection = false; 845 if (// In PIC mode, we need to emit the jump table to the same section as the 846 // function body itself, otherwise the label differences won't make sense. 847 // FIXME: Need a better predicate for this: what about custom entries? 848 MJTI->getEntryKind() == MachineJumpTableInfo::EK_LabelDifference32 || 849 // We should also do if the section name is NULL or function is declared 850 // in discardable section 851 // FIXME: this isn't the right predicate, should be based on the MCSection 852 // for the function. 853 F->isWeakForLinker()) { 854 OutStreamer.SwitchSection(getObjFileLowering().SectionForGlobal(F,Mang,TM)); 855 } else { 856 // Otherwise, drop it in the readonly section. 857 const MCSection *ReadOnlySection = 858 getObjFileLowering().getSectionForConstant(SectionKind::getReadOnly()); 859 OutStreamer.SwitchSection(ReadOnlySection); 860 JTInDiffSection = true; 861 } 862 863 EmitAlignment(Log2_32(MJTI->getEntryAlignment(*TM.getTargetData()))); 864 865 for (unsigned JTI = 0, e = JT.size(); JTI != e; ++JTI) { 866 const std::vector<MachineBasicBlock*> &JTBBs = JT[JTI].MBBs; 867 868 // If this jump table was deleted, ignore it. 869 if (JTBBs.empty()) continue; 870 871 // For the EK_LabelDifference32 entry, if the target supports .set, emit a 872 // .set directive for each unique entry. This reduces the number of 873 // relocations the assembler will generate for the jump table. 874 if (MJTI->getEntryKind() == MachineJumpTableInfo::EK_LabelDifference32 && 875 MAI->hasSetDirective()) { 876 SmallPtrSet<const MachineBasicBlock*, 16> EmittedSets; 877 const TargetLowering *TLI = TM.getTargetLowering(); 878 const MCExpr *Base = TLI->getPICJumpTableRelocBaseExpr(MF,JTI,OutContext); 879 for (unsigned ii = 0, ee = JTBBs.size(); ii != ee; ++ii) { 880 const MachineBasicBlock *MBB = JTBBs[ii]; 881 if (!EmittedSets.insert(MBB)) continue; 882 883 // .set LJTSet, LBB32-base 884 const MCExpr *LHS = 885 MCSymbolRefExpr::Create(MBB->getSymbol(), OutContext); 886 OutStreamer.EmitAssignment(GetJTSetSymbol(JTI, MBB->getNumber()), 887 MCBinaryExpr::CreateSub(LHS, Base, OutContext)); 888 } 889 } 890 891 // On some targets (e.g. Darwin) we want to emit two consequtive labels 892 // before each jump table. The first label is never referenced, but tells 893 // the assembler and linker the extents of the jump table object. The 894 // second label is actually referenced by the code. 895 if (JTInDiffSection && MAI->getLinkerPrivateGlobalPrefix()[0]) 896 // FIXME: This doesn't have to have any specific name, just any randomly 897 // named and numbered 'l' label would work. Simplify GetJTISymbol. 898 OutStreamer.EmitLabel(GetJTISymbol(JTI, true)); 899 900 OutStreamer.EmitLabel(GetJTISymbol(JTI)); 901 902 for (unsigned ii = 0, ee = JTBBs.size(); ii != ee; ++ii) 903 EmitJumpTableEntry(MJTI, JTBBs[ii], JTI); 904 } 905} 906 907/// EmitJumpTableEntry - Emit a jump table entry for the specified MBB to the 908/// current stream. 909void AsmPrinter::EmitJumpTableEntry(const MachineJumpTableInfo *MJTI, 910 const MachineBasicBlock *MBB, 911 unsigned UID) const { 912 const MCExpr *Value = 0; 913 switch (MJTI->getEntryKind()) { 914 case MachineJumpTableInfo::EK_Inline: 915 llvm_unreachable("Cannot emit EK_Inline jump table entry"); break; 916 case MachineJumpTableInfo::EK_Custom32: 917 Value = TM.getTargetLowering()->LowerCustomJumpTableEntry(MJTI, MBB, UID, 918 OutContext); 919 break; 920 case MachineJumpTableInfo::EK_BlockAddress: 921 // EK_BlockAddress - Each entry is a plain address of block, e.g.: 922 // .word LBB123 923 Value = MCSymbolRefExpr::Create(MBB->getSymbol(), OutContext); 924 break; 925 case MachineJumpTableInfo::EK_GPRel32BlockAddress: { 926 // EK_GPRel32BlockAddress - Each entry is an address of block, encoded 927 // with a relocation as gp-relative, e.g.: 928 // .gprel32 LBB123 929 MCSymbol *MBBSym = MBB->getSymbol(); 930 OutStreamer.EmitGPRel32Value(MCSymbolRefExpr::Create(MBBSym, OutContext)); 931 return; 932 } 933 934 case MachineJumpTableInfo::EK_LabelDifference32: { 935 // EK_LabelDifference32 - Each entry is the address of the block minus 936 // the address of the jump table. This is used for PIC jump tables where 937 // gprel32 is not supported. e.g.: 938 // .word LBB123 - LJTI1_2 939 // If the .set directive is supported, this is emitted as: 940 // .set L4_5_set_123, LBB123 - LJTI1_2 941 // .word L4_5_set_123 942 943 // If we have emitted set directives for the jump table entries, print 944 // them rather than the entries themselves. If we're emitting PIC, then 945 // emit the table entries as differences between two text section labels. 946 if (MAI->hasSetDirective()) { 947 // If we used .set, reference the .set's symbol. 948 Value = MCSymbolRefExpr::Create(GetJTSetSymbol(UID, MBB->getNumber()), 949 OutContext); 950 break; 951 } 952 // Otherwise, use the difference as the jump table entry. 953 Value = MCSymbolRefExpr::Create(MBB->getSymbol(), OutContext); 954 const MCExpr *JTI = MCSymbolRefExpr::Create(GetJTISymbol(UID), OutContext); 955 Value = MCBinaryExpr::CreateSub(Value, JTI, OutContext); 956 break; 957 } 958 } 959 960 assert(Value && "Unknown entry kind!"); 961 962 unsigned EntrySize = MJTI->getEntrySize(*TM.getTargetData()); 963 OutStreamer.EmitValue(Value, EntrySize, /*addrspace*/0); 964} 965 966 967/// EmitSpecialLLVMGlobal - Check to see if the specified global is a 968/// special global used by LLVM. If so, emit it and return true, otherwise 969/// do nothing and return false. 970bool AsmPrinter::EmitSpecialLLVMGlobal(const GlobalVariable *GV) { 971 if (GV->getName() == "llvm.used") { 972 if (MAI->hasNoDeadStrip()) // No need to emit this at all. 973 EmitLLVMUsedList(GV->getInitializer()); 974 return true; 975 } 976 977 // Ignore debug and non-emitted data. This handles llvm.compiler.used. 978 if (GV->getSection() == "llvm.metadata" || 979 GV->hasAvailableExternallyLinkage()) 980 return true; 981 982 if (!GV->hasAppendingLinkage()) return false; 983 984 assert(GV->hasInitializer() && "Not a special LLVM global!"); 985 986 const TargetData *TD = TM.getTargetData(); 987 unsigned Align = Log2_32(TD->getPointerPrefAlignment()); 988 if (GV->getName() == "llvm.global_ctors") { 989 OutStreamer.SwitchSection(getObjFileLowering().getStaticCtorSection()); 990 EmitAlignment(Align, 0); 991 EmitXXStructorList(GV->getInitializer()); 992 993 if (TM.getRelocationModel() == Reloc::Static && 994 MAI->hasStaticCtorDtorReferenceInStaticMode()) { 995 StringRef Sym(".constructors_used"); 996 OutStreamer.EmitSymbolAttribute(OutContext.GetOrCreateSymbol(Sym), 997 MCSA_Reference); 998 } 999 return true; 1000 } 1001 1002 if (GV->getName() == "llvm.global_dtors") { 1003 OutStreamer.SwitchSection(getObjFileLowering().getStaticDtorSection()); 1004 EmitAlignment(Align, 0); 1005 EmitXXStructorList(GV->getInitializer()); 1006 1007 if (TM.getRelocationModel() == Reloc::Static && 1008 MAI->hasStaticCtorDtorReferenceInStaticMode()) { 1009 StringRef Sym(".destructors_used"); 1010 OutStreamer.EmitSymbolAttribute(OutContext.GetOrCreateSymbol(Sym), 1011 MCSA_Reference); 1012 } 1013 return true; 1014 } 1015 1016 return false; 1017} 1018 1019/// EmitLLVMUsedList - For targets that define a MAI::UsedDirective, mark each 1020/// global in the specified llvm.used list for which emitUsedDirectiveFor 1021/// is true, as being used with this directive. 1022void AsmPrinter::EmitLLVMUsedList(Constant *List) { 1023 // Should be an array of 'i8*'. 1024 ConstantArray *InitList = dyn_cast<ConstantArray>(List); 1025 if (InitList == 0) return; 1026 1027 for (unsigned i = 0, e = InitList->getNumOperands(); i != e; ++i) { 1028 const GlobalValue *GV = 1029 dyn_cast<GlobalValue>(InitList->getOperand(i)->stripPointerCasts()); 1030 if (GV && getObjFileLowering().shouldEmitUsedDirectiveFor(GV, Mang)) 1031 OutStreamer.EmitSymbolAttribute(Mang->getSymbol(GV), MCSA_NoDeadStrip); 1032 } 1033} 1034 1035/// EmitXXStructorList - Emit the ctor or dtor list. This just prints out the 1036/// function pointers, ignoring the init priority. 1037void AsmPrinter::EmitXXStructorList(Constant *List) { 1038 // Should be an array of '{ int, void ()* }' structs. The first value is the 1039 // init priority, which we ignore. 1040 if (!isa<ConstantArray>(List)) return; 1041 ConstantArray *InitList = cast<ConstantArray>(List); 1042 for (unsigned i = 0, e = InitList->getNumOperands(); i != e; ++i) 1043 if (ConstantStruct *CS = dyn_cast<ConstantStruct>(InitList->getOperand(i))){ 1044 if (CS->getNumOperands() != 2) return; // Not array of 2-element structs. 1045 1046 if (CS->getOperand(1)->isNullValue()) 1047 return; // Found a null terminator, exit printing. 1048 // Emit the function pointer. 1049 EmitGlobalConstant(CS->getOperand(1)); 1050 } 1051} 1052 1053//===--------------------------------------------------------------------===// 1054// Emission and print routines 1055// 1056 1057/// EmitInt8 - Emit a byte directive and value. 1058/// 1059void AsmPrinter::EmitInt8(int Value) const { 1060 OutStreamer.EmitIntValue(Value, 1, 0/*addrspace*/); 1061} 1062 1063/// EmitInt16 - Emit a short directive and value. 1064/// 1065void AsmPrinter::EmitInt16(int Value) const { 1066 OutStreamer.EmitIntValue(Value, 2, 0/*addrspace*/); 1067} 1068 1069/// EmitInt32 - Emit a long directive and value. 1070/// 1071void AsmPrinter::EmitInt32(int Value) const { 1072 OutStreamer.EmitIntValue(Value, 4, 0/*addrspace*/); 1073} 1074 1075/// EmitLabelDifference - Emit something like ".long Hi-Lo" where the size 1076/// in bytes of the directive is specified by Size and Hi/Lo specify the 1077/// labels. This implicitly uses .set if it is available. 1078void AsmPrinter::EmitLabelDifference(const MCSymbol *Hi, const MCSymbol *Lo, 1079 unsigned Size) const { 1080 // Get the Hi-Lo expression. 1081 const MCExpr *Diff = 1082 MCBinaryExpr::CreateSub(MCSymbolRefExpr::Create(Hi, OutContext), 1083 MCSymbolRefExpr::Create(Lo, OutContext), 1084 OutContext); 1085 1086 if (!MAI->hasSetDirective()) { 1087 OutStreamer.EmitValue(Diff, Size, 0/*AddrSpace*/); 1088 return; 1089 } 1090 1091 // Otherwise, emit with .set (aka assignment). 1092 MCSymbol *SetLabel = GetTempSymbol("set", SetCounter++); 1093 OutStreamer.EmitAssignment(SetLabel, Diff); 1094 OutStreamer.EmitSymbolValue(SetLabel, Size, 0/*AddrSpace*/); 1095} 1096 1097/// EmitLabelOffsetDifference - Emit something like ".long Hi+Offset-Lo" 1098/// where the size in bytes of the directive is specified by Size and Hi/Lo 1099/// specify the labels. This implicitly uses .set if it is available. 1100void AsmPrinter::EmitLabelOffsetDifference(const MCSymbol *Hi, uint64_t Offset, 1101 const MCSymbol *Lo, unsigned Size) 1102 const { 1103 1104 // Emit Hi+Offset - Lo 1105 // Get the Hi+Offset expression. 1106 const MCExpr *Plus = 1107 MCBinaryExpr::CreateAdd(MCSymbolRefExpr::Create(Hi, OutContext), 1108 MCConstantExpr::Create(Offset, OutContext), 1109 OutContext); 1110 1111 // Get the Hi+Offset-Lo expression. 1112 const MCExpr *Diff = 1113 MCBinaryExpr::CreateSub(Plus, 1114 MCSymbolRefExpr::Create(Lo, OutContext), 1115 OutContext); 1116 1117 if (!MAI->hasSetDirective()) 1118 OutStreamer.EmitValue(Diff, 4, 0/*AddrSpace*/); 1119 else { 1120 // Otherwise, emit with .set (aka assignment). 1121 MCSymbol *SetLabel = GetTempSymbol("set", SetCounter++); 1122 OutStreamer.EmitAssignment(SetLabel, Diff); 1123 OutStreamer.EmitSymbolValue(SetLabel, 4, 0/*AddrSpace*/); 1124 } 1125} 1126 1127 1128//===----------------------------------------------------------------------===// 1129 1130// EmitAlignment - Emit an alignment directive to the specified power of 1131// two boundary. For example, if you pass in 3 here, you will get an 8 1132// byte alignment. If a global value is specified, and if that global has 1133// an explicit alignment requested, it will unconditionally override the 1134// alignment request. However, if ForcedAlignBits is specified, this value 1135// has final say: the ultimate alignment will be the max of ForcedAlignBits 1136// and the alignment computed with NumBits and the global. 1137// 1138// The algorithm is: 1139// Align = NumBits; 1140// if (GV && GV->hasalignment) Align = GV->getalignment(); 1141// Align = std::max(Align, ForcedAlignBits); 1142// 1143void AsmPrinter::EmitAlignment(unsigned NumBits, const GlobalValue *GV, 1144 unsigned ForcedAlignBits, 1145 bool UseFillExpr) const { 1146 if (GV && GV->getAlignment()) 1147 NumBits = Log2_32(GV->getAlignment()); 1148 NumBits = std::max(NumBits, ForcedAlignBits); 1149 1150 if (NumBits == 0) return; // No need to emit alignment. 1151 1152 if (getCurrentSection()->getKind().isText()) 1153 OutStreamer.EmitCodeAlignment(1 << NumBits); 1154 else 1155 OutStreamer.EmitValueToAlignment(1 << NumBits, 0, 1, 0); 1156} 1157 1158/// LowerConstant - Lower the specified LLVM Constant to an MCExpr. 1159/// 1160static const MCExpr *LowerConstant(const Constant *CV, AsmPrinter &AP) { 1161 MCContext &Ctx = AP.OutContext; 1162 1163 if (CV->isNullValue() || isa<UndefValue>(CV)) 1164 return MCConstantExpr::Create(0, Ctx); 1165 1166 if (const ConstantInt *CI = dyn_cast<ConstantInt>(CV)) 1167 return MCConstantExpr::Create(CI->getZExtValue(), Ctx); 1168 1169 if (const GlobalValue *GV = dyn_cast<GlobalValue>(CV)) 1170 return MCSymbolRefExpr::Create(AP.Mang->getSymbol(GV), Ctx); 1171 if (const BlockAddress *BA = dyn_cast<BlockAddress>(CV)) 1172 return MCSymbolRefExpr::Create(AP.GetBlockAddressSymbol(BA), Ctx); 1173 1174 const ConstantExpr *CE = dyn_cast<ConstantExpr>(CV); 1175 if (CE == 0) { 1176 llvm_unreachable("Unknown constant value to lower!"); 1177 return MCConstantExpr::Create(0, Ctx); 1178 } 1179 1180 switch (CE->getOpcode()) { 1181 default: 1182 // If the code isn't optimized, there may be outstanding folding 1183 // opportunities. Attempt to fold the expression using TargetData as a 1184 // last resort before giving up. 1185 if (Constant *C = 1186 ConstantFoldConstantExpression(CE, AP.TM.getTargetData())) 1187 if (C != CE) 1188 return LowerConstant(C, AP); 1189#ifndef NDEBUG 1190 CE->dump(); 1191#endif 1192 llvm_unreachable("FIXME: Don't support this constant expr"); 1193 case Instruction::GetElementPtr: { 1194 const TargetData &TD = *AP.TM.getTargetData(); 1195 // Generate a symbolic expression for the byte address 1196 const Constant *PtrVal = CE->getOperand(0); 1197 SmallVector<Value*, 8> IdxVec(CE->op_begin()+1, CE->op_end()); 1198 int64_t Offset = TD.getIndexedOffset(PtrVal->getType(), &IdxVec[0], 1199 IdxVec.size()); 1200 1201 const MCExpr *Base = LowerConstant(CE->getOperand(0), AP); 1202 if (Offset == 0) 1203 return Base; 1204 1205 // Truncate/sext the offset to the pointer size. 1206 if (TD.getPointerSizeInBits() != 64) { 1207 int SExtAmount = 64-TD.getPointerSizeInBits(); 1208 Offset = (Offset << SExtAmount) >> SExtAmount; 1209 } 1210 1211 return MCBinaryExpr::CreateAdd(Base, MCConstantExpr::Create(Offset, Ctx), 1212 Ctx); 1213 } 1214 1215 case Instruction::Trunc: 1216 // We emit the value and depend on the assembler to truncate the generated 1217 // expression properly. This is important for differences between 1218 // blockaddress labels. Since the two labels are in the same function, it 1219 // is reasonable to treat their delta as a 32-bit value. 1220 // FALL THROUGH. 1221 case Instruction::BitCast: 1222 return LowerConstant(CE->getOperand(0), AP); 1223 1224 case Instruction::IntToPtr: { 1225 const TargetData &TD = *AP.TM.getTargetData(); 1226 // Handle casts to pointers by changing them into casts to the appropriate 1227 // integer type. This promotes constant folding and simplifies this code. 1228 Constant *Op = CE->getOperand(0); 1229 Op = ConstantExpr::getIntegerCast(Op, TD.getIntPtrType(CV->getContext()), 1230 false/*ZExt*/); 1231 return LowerConstant(Op, AP); 1232 } 1233 1234 case Instruction::PtrToInt: { 1235 const TargetData &TD = *AP.TM.getTargetData(); 1236 // Support only foldable casts to/from pointers that can be eliminated by 1237 // changing the pointer to the appropriately sized integer type. 1238 Constant *Op = CE->getOperand(0); 1239 const Type *Ty = CE->getType(); 1240 1241 const MCExpr *OpExpr = LowerConstant(Op, AP); 1242 1243 // We can emit the pointer value into this slot if the slot is an 1244 // integer slot equal to the size of the pointer. 1245 if (TD.getTypeAllocSize(Ty) == TD.getTypeAllocSize(Op->getType())) 1246 return OpExpr; 1247 1248 // Otherwise the pointer is smaller than the resultant integer, mask off 1249 // the high bits so we are sure to get a proper truncation if the input is 1250 // a constant expr. 1251 unsigned InBits = TD.getTypeAllocSizeInBits(Op->getType()); 1252 const MCExpr *MaskExpr = MCConstantExpr::Create(~0ULL >> (64-InBits), Ctx); 1253 return MCBinaryExpr::CreateAnd(OpExpr, MaskExpr, Ctx); 1254 } 1255 1256 // The MC library also has a right-shift operator, but it isn't consistently 1257 // signed or unsigned between different targets. 1258 case Instruction::Add: 1259 case Instruction::Sub: 1260 case Instruction::Mul: 1261 case Instruction::SDiv: 1262 case Instruction::SRem: 1263 case Instruction::Shl: 1264 case Instruction::And: 1265 case Instruction::Or: 1266 case Instruction::Xor: { 1267 const MCExpr *LHS = LowerConstant(CE->getOperand(0), AP); 1268 const MCExpr *RHS = LowerConstant(CE->getOperand(1), AP); 1269 switch (CE->getOpcode()) { 1270 default: llvm_unreachable("Unknown binary operator constant cast expr"); 1271 case Instruction::Add: return MCBinaryExpr::CreateAdd(LHS, RHS, Ctx); 1272 case Instruction::Sub: return MCBinaryExpr::CreateSub(LHS, RHS, Ctx); 1273 case Instruction::Mul: return MCBinaryExpr::CreateMul(LHS, RHS, Ctx); 1274 case Instruction::SDiv: return MCBinaryExpr::CreateDiv(LHS, RHS, Ctx); 1275 case Instruction::SRem: return MCBinaryExpr::CreateMod(LHS, RHS, Ctx); 1276 case Instruction::Shl: return MCBinaryExpr::CreateShl(LHS, RHS, Ctx); 1277 case Instruction::And: return MCBinaryExpr::CreateAnd(LHS, RHS, Ctx); 1278 case Instruction::Or: return MCBinaryExpr::CreateOr (LHS, RHS, Ctx); 1279 case Instruction::Xor: return MCBinaryExpr::CreateXor(LHS, RHS, Ctx); 1280 } 1281 } 1282 } 1283} 1284 1285static void EmitGlobalConstantArray(const ConstantArray *CA, unsigned AddrSpace, 1286 AsmPrinter &AP) { 1287 if (AddrSpace != 0 || !CA->isString()) { 1288 // Not a string. Print the values in successive locations 1289 for (unsigned i = 0, e = CA->getNumOperands(); i != e; ++i) 1290 AP.EmitGlobalConstant(CA->getOperand(i), AddrSpace); 1291 return; 1292 } 1293 1294 // Otherwise, it can be emitted as .ascii. 1295 SmallVector<char, 128> TmpVec; 1296 TmpVec.reserve(CA->getNumOperands()); 1297 for (unsigned i = 0, e = CA->getNumOperands(); i != e; ++i) 1298 TmpVec.push_back(cast<ConstantInt>(CA->getOperand(i))->getZExtValue()); 1299 1300 AP.OutStreamer.EmitBytes(StringRef(TmpVec.data(), TmpVec.size()), AddrSpace); 1301} 1302 1303static void EmitGlobalConstantVector(const ConstantVector *CV, 1304 unsigned AddrSpace, AsmPrinter &AP) { 1305 for (unsigned i = 0, e = CV->getType()->getNumElements(); i != e; ++i) 1306 AP.EmitGlobalConstant(CV->getOperand(i), AddrSpace); 1307} 1308 1309static void EmitGlobalConstantStruct(const ConstantStruct *CS, 1310 unsigned AddrSpace, AsmPrinter &AP) { 1311 // Print the fields in successive locations. Pad to align if needed! 1312 const TargetData *TD = AP.TM.getTargetData(); 1313 unsigned Size = TD->getTypeAllocSize(CS->getType()); 1314 const StructLayout *Layout = TD->getStructLayout(CS->getType()); 1315 uint64_t SizeSoFar = 0; 1316 for (unsigned i = 0, e = CS->getNumOperands(); i != e; ++i) { 1317 const Constant *Field = CS->getOperand(i); 1318 1319 // Check if padding is needed and insert one or more 0s. 1320 uint64_t FieldSize = TD->getTypeAllocSize(Field->getType()); 1321 uint64_t PadSize = ((i == e-1 ? Size : Layout->getElementOffset(i+1)) 1322 - Layout->getElementOffset(i)) - FieldSize; 1323 SizeSoFar += FieldSize + PadSize; 1324 1325 // Now print the actual field value. 1326 AP.EmitGlobalConstant(Field, AddrSpace); 1327 1328 // Insert padding - this may include padding to increase the size of the 1329 // current field up to the ABI size (if the struct is not packed) as well 1330 // as padding to ensure that the next field starts at the right offset. 1331 AP.OutStreamer.EmitZeros(PadSize, AddrSpace); 1332 } 1333 assert(SizeSoFar == Layout->getSizeInBytes() && 1334 "Layout of constant struct may be incorrect!"); 1335} 1336 1337static void EmitGlobalConstantUnion(const ConstantUnion *CU, 1338 unsigned AddrSpace, AsmPrinter &AP) { 1339 const TargetData *TD = AP.TM.getTargetData(); 1340 unsigned Size = TD->getTypeAllocSize(CU->getType()); 1341 1342 const Constant *Contents = CU->getOperand(0); 1343 unsigned FilledSize = TD->getTypeAllocSize(Contents->getType()); 1344 1345 // Print the actually filled part 1346 AP.EmitGlobalConstant(Contents, AddrSpace); 1347 1348 // And pad with enough zeroes 1349 AP.OutStreamer.EmitZeros(Size-FilledSize, AddrSpace); 1350} 1351 1352static void EmitGlobalConstantFP(const ConstantFP *CFP, unsigned AddrSpace, 1353 AsmPrinter &AP) { 1354 // FP Constants are printed as integer constants to avoid losing 1355 // precision. 1356 if (CFP->getType()->isDoubleTy()) { 1357 if (AP.isVerbose()) { 1358 double Val = CFP->getValueAPF().convertToDouble(); 1359 AP.OutStreamer.GetCommentOS() << "double " << Val << '\n'; 1360 } 1361 1362 uint64_t Val = CFP->getValueAPF().bitcastToAPInt().getZExtValue(); 1363 AP.OutStreamer.EmitIntValue(Val, 8, AddrSpace); 1364 return; 1365 } 1366 1367 if (CFP->getType()->isFloatTy()) { 1368 if (AP.isVerbose()) { 1369 float Val = CFP->getValueAPF().convertToFloat(); 1370 AP.OutStreamer.GetCommentOS() << "float " << Val << '\n'; 1371 } 1372 uint64_t Val = CFP->getValueAPF().bitcastToAPInt().getZExtValue(); 1373 AP.OutStreamer.EmitIntValue(Val, 4, AddrSpace); 1374 return; 1375 } 1376 1377 if (CFP->getType()->isX86_FP80Ty()) { 1378 // all long double variants are printed as hex 1379 // API needed to prevent premature destruction 1380 APInt API = CFP->getValueAPF().bitcastToAPInt(); 1381 const uint64_t *p = API.getRawData(); 1382 if (AP.isVerbose()) { 1383 // Convert to double so we can print the approximate val as a comment. 1384 APFloat DoubleVal = CFP->getValueAPF(); 1385 bool ignored; 1386 DoubleVal.convert(APFloat::IEEEdouble, APFloat::rmNearestTiesToEven, 1387 &ignored); 1388 AP.OutStreamer.GetCommentOS() << "x86_fp80 ~= " 1389 << DoubleVal.convertToDouble() << '\n'; 1390 } 1391 1392 if (AP.TM.getTargetData()->isBigEndian()) { 1393 AP.OutStreamer.EmitIntValue(p[1], 2, AddrSpace); 1394 AP.OutStreamer.EmitIntValue(p[0], 8, AddrSpace); 1395 } else { 1396 AP.OutStreamer.EmitIntValue(p[0], 8, AddrSpace); 1397 AP.OutStreamer.EmitIntValue(p[1], 2, AddrSpace); 1398 } 1399 1400 // Emit the tail padding for the long double. 1401 const TargetData &TD = *AP.TM.getTargetData(); 1402 AP.OutStreamer.EmitZeros(TD.getTypeAllocSize(CFP->getType()) - 1403 TD.getTypeStoreSize(CFP->getType()), AddrSpace); 1404 return; 1405 } 1406 1407 assert(CFP->getType()->isPPC_FP128Ty() && 1408 "Floating point constant type not handled"); 1409 // All long double variants are printed as hex 1410 // API needed to prevent premature destruction. 1411 APInt API = CFP->getValueAPF().bitcastToAPInt(); 1412 const uint64_t *p = API.getRawData(); 1413 if (AP.TM.getTargetData()->isBigEndian()) { 1414 AP.OutStreamer.EmitIntValue(p[0], 8, AddrSpace); 1415 AP.OutStreamer.EmitIntValue(p[1], 8, AddrSpace); 1416 } else { 1417 AP.OutStreamer.EmitIntValue(p[1], 8, AddrSpace); 1418 AP.OutStreamer.EmitIntValue(p[0], 8, AddrSpace); 1419 } 1420} 1421 1422static void EmitGlobalConstantLargeInt(const ConstantInt *CI, 1423 unsigned AddrSpace, AsmPrinter &AP) { 1424 const TargetData *TD = AP.TM.getTargetData(); 1425 unsigned BitWidth = CI->getBitWidth(); 1426 assert((BitWidth & 63) == 0 && "only support multiples of 64-bits"); 1427 1428 // We don't expect assemblers to support integer data directives 1429 // for more than 64 bits, so we emit the data in at most 64-bit 1430 // quantities at a time. 1431 const uint64_t *RawData = CI->getValue().getRawData(); 1432 for (unsigned i = 0, e = BitWidth / 64; i != e; ++i) { 1433 uint64_t Val = TD->isBigEndian() ? RawData[e - i - 1] : RawData[i]; 1434 AP.OutStreamer.EmitIntValue(Val, 8, AddrSpace); 1435 } 1436} 1437 1438/// EmitGlobalConstant - Print a general LLVM constant to the .s file. 1439void AsmPrinter::EmitGlobalConstant(const Constant *CV, unsigned AddrSpace) { 1440 if (isa<ConstantAggregateZero>(CV) || isa<UndefValue>(CV)) { 1441 uint64_t Size = TM.getTargetData()->getTypeAllocSize(CV->getType()); 1442 if (Size == 0) Size = 1; // An empty "_foo:" followed by a section is undef. 1443 return OutStreamer.EmitZeros(Size, AddrSpace); 1444 } 1445 1446 if (const ConstantInt *CI = dyn_cast<ConstantInt>(CV)) { 1447 unsigned Size = TM.getTargetData()->getTypeAllocSize(CV->getType()); 1448 switch (Size) { 1449 case 1: 1450 case 2: 1451 case 4: 1452 case 8: 1453 if (isVerbose()) 1454 OutStreamer.GetCommentOS() << format("0x%llx\n", CI->getZExtValue()); 1455 OutStreamer.EmitIntValue(CI->getZExtValue(), Size, AddrSpace); 1456 return; 1457 default: 1458 EmitGlobalConstantLargeInt(CI, AddrSpace, *this); 1459 return; 1460 } 1461 } 1462 1463 if (const ConstantArray *CVA = dyn_cast<ConstantArray>(CV)) 1464 return EmitGlobalConstantArray(CVA, AddrSpace, *this); 1465 1466 if (const ConstantStruct *CVS = dyn_cast<ConstantStruct>(CV)) 1467 return EmitGlobalConstantStruct(CVS, AddrSpace, *this); 1468 1469 if (const ConstantFP *CFP = dyn_cast<ConstantFP>(CV)) 1470 return EmitGlobalConstantFP(CFP, AddrSpace, *this); 1471 1472 if (isa<ConstantPointerNull>(CV)) { 1473 unsigned Size = TM.getTargetData()->getTypeAllocSize(CV->getType()); 1474 OutStreamer.EmitIntValue(0, Size, AddrSpace); 1475 return; 1476 } 1477 1478 if (const ConstantUnion *CVU = dyn_cast<ConstantUnion>(CV)) 1479 return EmitGlobalConstantUnion(CVU, AddrSpace, *this); 1480 1481 if (const ConstantVector *V = dyn_cast<ConstantVector>(CV)) 1482 return EmitGlobalConstantVector(V, AddrSpace, *this); 1483 1484 // Otherwise, it must be a ConstantExpr. Lower it to an MCExpr, then emit it 1485 // thread the streamer with EmitValue. 1486 OutStreamer.EmitValue(LowerConstant(CV, *this), 1487 TM.getTargetData()->getTypeAllocSize(CV->getType()), 1488 AddrSpace); 1489} 1490 1491void AsmPrinter::EmitMachineConstantPoolValue(MachineConstantPoolValue *MCPV) { 1492 // Target doesn't support this yet! 1493 llvm_unreachable("Target does not support EmitMachineConstantPoolValue"); 1494} 1495 1496void AsmPrinter::printOffset(int64_t Offset, raw_ostream &OS) const { 1497 if (Offset > 0) 1498 OS << '+' << Offset; 1499 else if (Offset < 0) 1500 OS << Offset; 1501} 1502 1503//===----------------------------------------------------------------------===// 1504// Symbol Lowering Routines. 1505//===----------------------------------------------------------------------===// 1506 1507/// GetTempSymbol - Return the MCSymbol corresponding to the assembler 1508/// temporary label with the specified stem and unique ID. 1509MCSymbol *AsmPrinter::GetTempSymbol(StringRef Name, unsigned ID) const { 1510 return OutContext.GetOrCreateSymbol(Twine(MAI->getPrivateGlobalPrefix()) + 1511 Name + Twine(ID)); 1512} 1513 1514/// GetTempSymbol - Return an assembler temporary label with the specified 1515/// stem. 1516MCSymbol *AsmPrinter::GetTempSymbol(StringRef Name) const { 1517 return OutContext.GetOrCreateSymbol(Twine(MAI->getPrivateGlobalPrefix())+ 1518 Name); 1519} 1520 1521 1522MCSymbol *AsmPrinter::GetBlockAddressSymbol(const BlockAddress *BA) const { 1523 return MMI->getAddrLabelSymbol(BA->getBasicBlock()); 1524} 1525 1526MCSymbol *AsmPrinter::GetBlockAddressSymbol(const BasicBlock *BB) const { 1527 return MMI->getAddrLabelSymbol(BB); 1528} 1529 1530/// GetCPISymbol - Return the symbol for the specified constant pool entry. 1531MCSymbol *AsmPrinter::GetCPISymbol(unsigned CPID) const { 1532 return OutContext.GetOrCreateSymbol 1533 (Twine(MAI->getPrivateGlobalPrefix()) + "CPI" + Twine(getFunctionNumber()) 1534 + "_" + Twine(CPID)); 1535} 1536 1537/// GetJTISymbol - Return the symbol for the specified jump table entry. 1538MCSymbol *AsmPrinter::GetJTISymbol(unsigned JTID, bool isLinkerPrivate) const { 1539 return MF->getJTISymbol(JTID, OutContext, isLinkerPrivate); 1540} 1541 1542/// GetJTSetSymbol - Return the symbol for the specified jump table .set 1543/// FIXME: privatize to AsmPrinter. 1544MCSymbol *AsmPrinter::GetJTSetSymbol(unsigned UID, unsigned MBBID) const { 1545 return OutContext.GetOrCreateSymbol 1546 (Twine(MAI->getPrivateGlobalPrefix()) + Twine(getFunctionNumber()) + "_" + 1547 Twine(UID) + "_set_" + Twine(MBBID)); 1548} 1549 1550/// GetSymbolWithGlobalValueBase - Return the MCSymbol for a symbol with 1551/// global value name as its base, with the specified suffix, and where the 1552/// symbol is forced to have private linkage if ForcePrivate is true. 1553MCSymbol *AsmPrinter::GetSymbolWithGlobalValueBase(const GlobalValue *GV, 1554 StringRef Suffix, 1555 bool ForcePrivate) const { 1556 SmallString<60> NameStr; 1557 Mang->getNameWithPrefix(NameStr, GV, ForcePrivate); 1558 NameStr.append(Suffix.begin(), Suffix.end()); 1559 return OutContext.GetOrCreateSymbol(NameStr.str()); 1560} 1561 1562/// GetExternalSymbolSymbol - Return the MCSymbol for the specified 1563/// ExternalSymbol. 1564MCSymbol *AsmPrinter::GetExternalSymbolSymbol(StringRef Sym) const { 1565 SmallString<60> NameStr; 1566 Mang->getNameWithPrefix(NameStr, Sym); 1567 return OutContext.GetOrCreateSymbol(NameStr.str()); 1568} 1569 1570 1571 1572/// PrintParentLoopComment - Print comments about parent loops of this one. 1573static void PrintParentLoopComment(raw_ostream &OS, const MachineLoop *Loop, 1574 unsigned FunctionNumber) { 1575 if (Loop == 0) return; 1576 PrintParentLoopComment(OS, Loop->getParentLoop(), FunctionNumber); 1577 OS.indent(Loop->getLoopDepth()*2) 1578 << "Parent Loop BB" << FunctionNumber << "_" 1579 << Loop->getHeader()->getNumber() 1580 << " Depth=" << Loop->getLoopDepth() << '\n'; 1581} 1582 1583 1584/// PrintChildLoopComment - Print comments about child loops within 1585/// the loop for this basic block, with nesting. 1586static void PrintChildLoopComment(raw_ostream &OS, const MachineLoop *Loop, 1587 unsigned FunctionNumber) { 1588 // Add child loop information 1589 for (MachineLoop::iterator CL = Loop->begin(), E = Loop->end();CL != E; ++CL){ 1590 OS.indent((*CL)->getLoopDepth()*2) 1591 << "Child Loop BB" << FunctionNumber << "_" 1592 << (*CL)->getHeader()->getNumber() << " Depth " << (*CL)->getLoopDepth() 1593 << '\n'; 1594 PrintChildLoopComment(OS, *CL, FunctionNumber); 1595 } 1596} 1597 1598/// EmitBasicBlockLoopComments - Pretty-print comments for basic blocks. 1599static void EmitBasicBlockLoopComments(const MachineBasicBlock &MBB, 1600 const MachineLoopInfo *LI, 1601 const AsmPrinter &AP) { 1602 // Add loop depth information 1603 const MachineLoop *Loop = LI->getLoopFor(&MBB); 1604 if (Loop == 0) return; 1605 1606 MachineBasicBlock *Header = Loop->getHeader(); 1607 assert(Header && "No header for loop"); 1608 1609 // If this block is not a loop header, just print out what is the loop header 1610 // and return. 1611 if (Header != &MBB) { 1612 AP.OutStreamer.AddComment(" in Loop: Header=BB" + 1613 Twine(AP.getFunctionNumber())+"_" + 1614 Twine(Loop->getHeader()->getNumber())+ 1615 " Depth="+Twine(Loop->getLoopDepth())); 1616 return; 1617 } 1618 1619 // Otherwise, it is a loop header. Print out information about child and 1620 // parent loops. 1621 raw_ostream &OS = AP.OutStreamer.GetCommentOS(); 1622 1623 PrintParentLoopComment(OS, Loop->getParentLoop(), AP.getFunctionNumber()); 1624 1625 OS << "=>"; 1626 OS.indent(Loop->getLoopDepth()*2-2); 1627 1628 OS << "This "; 1629 if (Loop->empty()) 1630 OS << "Inner "; 1631 OS << "Loop Header: Depth=" + Twine(Loop->getLoopDepth()) << '\n'; 1632 1633 PrintChildLoopComment(OS, Loop, AP.getFunctionNumber()); 1634} 1635 1636 1637/// EmitBasicBlockStart - This method prints the label for the specified 1638/// MachineBasicBlock, an alignment (if present) and a comment describing 1639/// it if appropriate. 1640void AsmPrinter::EmitBasicBlockStart(const MachineBasicBlock *MBB) const { 1641 // Emit an alignment directive for this block, if needed. 1642 if (unsigned Align = MBB->getAlignment()) 1643 EmitAlignment(Log2_32(Align)); 1644 1645 // If the block has its address taken, emit any labels that were used to 1646 // reference the block. It is possible that there is more than one label 1647 // here, because multiple LLVM BB's may have been RAUW'd to this block after 1648 // the references were generated. 1649 if (MBB->hasAddressTaken()) { 1650 const BasicBlock *BB = MBB->getBasicBlock(); 1651 if (isVerbose()) 1652 OutStreamer.AddComment("Block address taken"); 1653 1654 std::vector<MCSymbol*> Syms = MMI->getAddrLabelSymbolToEmit(BB); 1655 1656 for (unsigned i = 0, e = Syms.size(); i != e; ++i) 1657 OutStreamer.EmitLabel(Syms[i]); 1658 } 1659 1660 // Print the main label for the block. 1661 if (MBB->pred_empty() || isBlockOnlyReachableByFallthrough(MBB)) { 1662 if (isVerbose() && OutStreamer.hasRawTextSupport()) { 1663 if (const BasicBlock *BB = MBB->getBasicBlock()) 1664 if (BB->hasName()) 1665 OutStreamer.AddComment("%" + BB->getName()); 1666 1667 EmitBasicBlockLoopComments(*MBB, LI, *this); 1668 1669 // NOTE: Want this comment at start of line, don't emit with AddComment. 1670 OutStreamer.EmitRawText(Twine(MAI->getCommentString()) + " BB#" + 1671 Twine(MBB->getNumber()) + ":"); 1672 } 1673 } else { 1674 if (isVerbose()) { 1675 if (const BasicBlock *BB = MBB->getBasicBlock()) 1676 if (BB->hasName()) 1677 OutStreamer.AddComment("%" + BB->getName()); 1678 EmitBasicBlockLoopComments(*MBB, LI, *this); 1679 } 1680 1681 OutStreamer.EmitLabel(MBB->getSymbol()); 1682 } 1683} 1684 1685void AsmPrinter::EmitVisibility(MCSymbol *Sym, unsigned Visibility) const { 1686 MCSymbolAttr Attr = MCSA_Invalid; 1687 1688 switch (Visibility) { 1689 default: break; 1690 case GlobalValue::HiddenVisibility: 1691 Attr = MAI->getHiddenVisibilityAttr(); 1692 break; 1693 case GlobalValue::ProtectedVisibility: 1694 Attr = MAI->getProtectedVisibilityAttr(); 1695 break; 1696 } 1697 1698 if (Attr != MCSA_Invalid) 1699 OutStreamer.EmitSymbolAttribute(Sym, Attr); 1700} 1701 1702/// isBlockOnlyReachableByFallthough - Return true if the basic block has 1703/// exactly one predecessor and the control transfer mechanism between 1704/// the predecessor and this block is a fall-through. 1705bool AsmPrinter:: 1706isBlockOnlyReachableByFallthrough(const MachineBasicBlock *MBB) const { 1707 // If this is a landing pad, it isn't a fall through. If it has no preds, 1708 // then nothing falls through to it. 1709 if (MBB->isLandingPad() || MBB->pred_empty()) 1710 return false; 1711 1712 // If there isn't exactly one predecessor, it can't be a fall through. 1713 MachineBasicBlock::const_pred_iterator PI = MBB->pred_begin(), PI2 = PI; 1714 ++PI2; 1715 if (PI2 != MBB->pred_end()) 1716 return false; 1717 1718 // The predecessor has to be immediately before this block. 1719 const MachineBasicBlock *Pred = *PI; 1720 1721 if (!Pred->isLayoutSuccessor(MBB)) 1722 return false; 1723 1724 // If the block is completely empty, then it definitely does fall through. 1725 if (Pred->empty()) 1726 return true; 1727 1728 // Otherwise, check the last instruction. 1729 const MachineInstr &LastInst = Pred->back(); 1730 return !LastInst.getDesc().isBarrier(); 1731} 1732 1733 1734 1735GCMetadataPrinter *AsmPrinter::GetOrCreateGCPrinter(GCStrategy *S) { 1736 if (!S->usesMetadata()) 1737 return 0; 1738 1739 gcp_map_type &GCMap = getGCMap(GCMetadataPrinters); 1740 gcp_map_type::iterator GCPI = GCMap.find(S); 1741 if (GCPI != GCMap.end()) 1742 return GCPI->second; 1743 1744 const char *Name = S->getName().c_str(); 1745 1746 for (GCMetadataPrinterRegistry::iterator 1747 I = GCMetadataPrinterRegistry::begin(), 1748 E = GCMetadataPrinterRegistry::end(); I != E; ++I) 1749 if (strcmp(Name, I->getName()) == 0) { 1750 GCMetadataPrinter *GMP = I->instantiate(); 1751 GMP->S = S; 1752 GCMap.insert(std::make_pair(S, GMP)); 1753 return GMP; 1754 } 1755 1756 report_fatal_error("no GCMetadataPrinter registered for GC: " + Twine(Name)); 1757 return 0; 1758} 1759 1760