AsmPrinter.cpp revision 5e94a08f3ca2123d63bd7c72561702f1f188b5de
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 96const TargetLoweringObjectFile &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()); 231 232 // If the alignment is specified, we *must* obey it. Overaligning a global 233 // with a specified alignment is a prompt way to break globals emitted to 234 // sections and expected to be contiguous (e.g. ObjC metadata). 235 unsigned AlignLog; 236 if (unsigned GVAlign = GV->getAlignment()) 237 AlignLog = Log2_32(GVAlign); 238 else 239 AlignLog = TD->getPreferredAlignmentLog(GV); 240 241 // Handle common and BSS local symbols (.lcomm). 242 if (GVKind.isCommon() || GVKind.isBSSLocal()) { 243 if (Size == 0) Size = 1; // .comm Foo, 0 is undefined, avoid it. 244 245 if (isVerbose()) { 246 WriteAsOperand(OutStreamer.GetCommentOS(), GV, 247 /*PrintType=*/false, GV->getParent()); 248 OutStreamer.GetCommentOS() << '\n'; 249 } 250 251 // Handle common symbols. 252 if (GVKind.isCommon()) { 253 // .comm _foo, 42, 4 254 OutStreamer.EmitCommonSymbol(GVSym, Size, 1 << AlignLog); 255 return; 256 } 257 258 // Handle local BSS symbols. 259 if (MAI->hasMachoZeroFillDirective()) { 260 const MCSection *TheSection = 261 getObjFileLowering().SectionForGlobal(GV, GVKind, Mang, TM); 262 // .zerofill __DATA, __bss, _foo, 400, 5 263 OutStreamer.EmitZerofill(TheSection, GVSym, Size, 1 << AlignLog); 264 return; 265 } 266 267 if (MAI->hasLCOMMDirective()) { 268 // .lcomm _foo, 42 269 OutStreamer.EmitLocalCommonSymbol(GVSym, Size); 270 return; 271 } 272 273 // .local _foo 274 OutStreamer.EmitSymbolAttribute(GVSym, MCSA_Local); 275 // .comm _foo, 42, 4 276 OutStreamer.EmitCommonSymbol(GVSym, Size, 1 << AlignLog); 277 return; 278 } 279 280 const MCSection *TheSection = 281 getObjFileLowering().SectionForGlobal(GV, GVKind, Mang, TM); 282 283 // Handle the zerofill directive on darwin, which is a special form of BSS 284 // emission. 285 if (GVKind.isBSSExtern() && MAI->hasMachoZeroFillDirective()) { 286 // .globl _foo 287 OutStreamer.EmitSymbolAttribute(GVSym, MCSA_Global); 288 // .zerofill __DATA, __common, _foo, 400, 5 289 OutStreamer.EmitZerofill(TheSection, GVSym, Size, 1 << AlignLog); 290 return; 291 } 292 293 OutStreamer.SwitchSection(TheSection); 294 295 EmitLinkage(GV->getLinkage(), GVSym); 296 EmitAlignment(AlignLog, GV); 297 298 if (isVerbose()) { 299 WriteAsOperand(OutStreamer.GetCommentOS(), GV, 300 /*PrintType=*/false, GV->getParent()); 301 OutStreamer.GetCommentOS() << '\n'; 302 } 303 OutStreamer.EmitLabel(GVSym); 304 305 EmitGlobalConstant(GV->getInitializer()); 306 307 if (MAI->hasDotTypeDotSizeDirective()) 308 // .size foo, 42 309 OutStreamer.EmitELFSize(GVSym, MCConstantExpr::Create(Size, OutContext)); 310 311 OutStreamer.AddBlankLine(); 312} 313 314/// EmitFunctionHeader - This method emits the header for the current 315/// function. 316void AsmPrinter::EmitFunctionHeader() { 317 // Print out constants referenced by the function 318 EmitConstantPool(); 319 320 // Print the 'header' of function. 321 const Function *F = MF->getFunction(); 322 323 OutStreamer.SwitchSection(getObjFileLowering().SectionForGlobal(F, Mang, TM)); 324 EmitVisibility(CurrentFnSym, F->getVisibility()); 325 326 EmitLinkage(F->getLinkage(), CurrentFnSym); 327 EmitAlignment(MF->getAlignment(), F); 328 329 if (MAI->hasDotTypeDotSizeDirective()) 330 OutStreamer.EmitSymbolAttribute(CurrentFnSym, MCSA_ELF_TypeFunction); 331 332 if (isVerbose()) { 333 WriteAsOperand(OutStreamer.GetCommentOS(), F, 334 /*PrintType=*/false, F->getParent()); 335 OutStreamer.GetCommentOS() << '\n'; 336 } 337 338 // Emit the CurrentFnSym. This is a virtual function to allow targets to 339 // do their wild and crazy things as required. 340 EmitFunctionEntryLabel(); 341 342 // If the function had address-taken blocks that got deleted, then we have 343 // references to the dangling symbols. Emit them at the start of the function 344 // so that we don't get references to undefined symbols. 345 std::vector<MCSymbol*> DeadBlockSyms; 346 MMI->takeDeletedSymbolsForFunction(F, DeadBlockSyms); 347 for (unsigned i = 0, e = DeadBlockSyms.size(); i != e; ++i) { 348 OutStreamer.AddComment("Address taken block that was later removed"); 349 OutStreamer.EmitLabel(DeadBlockSyms[i]); 350 } 351 352 // Add some workaround for linkonce linkage on Cygwin\MinGW. 353 if (MAI->getLinkOnceDirective() != 0 && 354 (F->hasLinkOnceLinkage() || F->hasWeakLinkage())) { 355 // FIXME: What is this? 356 MCSymbol *FakeStub = 357 OutContext.GetOrCreateSymbol(Twine("Lllvm$workaround$fake$stub$")+ 358 CurrentFnSym->getName()); 359 OutStreamer.EmitLabel(FakeStub); 360 } 361 362 // Emit pre-function debug and/or EH information. 363 if (DE) { 364 if (TimePassesIsEnabled) { 365 NamedRegionTimer T(EHTimerName, DWARFGroupName); 366 DE->BeginFunction(MF); 367 } else { 368 DE->BeginFunction(MF); 369 } 370 } 371 if (DD) { 372 if (TimePassesIsEnabled) { 373 NamedRegionTimer T(DbgTimerName, DWARFGroupName); 374 DD->beginFunction(MF); 375 } else { 376 DD->beginFunction(MF); 377 } 378 } 379} 380 381/// EmitFunctionEntryLabel - Emit the label that is the entrypoint for the 382/// function. This can be overridden by targets as required to do custom stuff. 383void AsmPrinter::EmitFunctionEntryLabel() { 384 OutStreamer.EmitLabel(CurrentFnSym); 385} 386 387 388/// EmitComments - Pretty-print comments for instructions. 389static void EmitComments(const MachineInstr &MI, raw_ostream &CommentOS) { 390 const MachineFunction *MF = MI.getParent()->getParent(); 391 const TargetMachine &TM = MF->getTarget(); 392 393 DebugLoc DL = MI.getDebugLoc(); 394 if (!DL.isUnknown()) { // Print source line info. 395 DIScope Scope(DL.getScope(MF->getFunction()->getContext())); 396 // Omit the directory, because it's likely to be long and uninteresting. 397 if (Scope.Verify()) 398 CommentOS << Scope.getFilename(); 399 else 400 CommentOS << "<unknown>"; 401 CommentOS << ':' << DL.getLine(); 402 if (DL.getCol() != 0) 403 CommentOS << ':' << DL.getCol(); 404 CommentOS << '\n'; 405 } 406 407 // Check for spills and reloads 408 int FI; 409 410 const MachineFrameInfo *FrameInfo = MF->getFrameInfo(); 411 412 // We assume a single instruction only has a spill or reload, not 413 // both. 414 const MachineMemOperand *MMO; 415 if (TM.getInstrInfo()->isLoadFromStackSlotPostFE(&MI, FI)) { 416 if (FrameInfo->isSpillSlotObjectIndex(FI)) { 417 MMO = *MI.memoperands_begin(); 418 CommentOS << MMO->getSize() << "-byte Reload\n"; 419 } 420 } else if (TM.getInstrInfo()->hasLoadFromStackSlot(&MI, MMO, FI)) { 421 if (FrameInfo->isSpillSlotObjectIndex(FI)) 422 CommentOS << MMO->getSize() << "-byte Folded Reload\n"; 423 } else if (TM.getInstrInfo()->isStoreToStackSlotPostFE(&MI, FI)) { 424 if (FrameInfo->isSpillSlotObjectIndex(FI)) { 425 MMO = *MI.memoperands_begin(); 426 CommentOS << MMO->getSize() << "-byte Spill\n"; 427 } 428 } else if (TM.getInstrInfo()->hasStoreToStackSlot(&MI, MMO, FI)) { 429 if (FrameInfo->isSpillSlotObjectIndex(FI)) 430 CommentOS << MMO->getSize() << "-byte Folded Spill\n"; 431 } 432 433 // Check for spill-induced copies 434 unsigned SrcReg, DstReg, SrcSubIdx, DstSubIdx; 435 if (TM.getInstrInfo()->isMoveInstr(MI, SrcReg, DstReg, 436 SrcSubIdx, DstSubIdx)) { 437 if (MI.getAsmPrinterFlag(MachineInstr::ReloadReuse)) 438 CommentOS << " Reload Reuse\n"; 439 } 440} 441 442/// EmitImplicitDef - This method emits the specified machine instruction 443/// that is an implicit def. 444static void EmitImplicitDef(const MachineInstr *MI, AsmPrinter &AP) { 445 unsigned RegNo = MI->getOperand(0).getReg(); 446 AP.OutStreamer.AddComment(Twine("implicit-def: ") + 447 AP.TM.getRegisterInfo()->getName(RegNo)); 448 AP.OutStreamer.AddBlankLine(); 449} 450 451static void EmitKill(const MachineInstr *MI, AsmPrinter &AP) { 452 std::string Str = "kill:"; 453 for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) { 454 const MachineOperand &Op = MI->getOperand(i); 455 assert(Op.isReg() && "KILL instruction must have only register operands"); 456 Str += ' '; 457 Str += AP.TM.getRegisterInfo()->getName(Op.getReg()); 458 Str += (Op.isDef() ? "<def>" : "<kill>"); 459 } 460 AP.OutStreamer.AddComment(Str); 461 AP.OutStreamer.AddBlankLine(); 462} 463 464/// EmitDebugValueComment - This method handles the target-independent form 465/// of DBG_VALUE, returning true if it was able to do so. A false return 466/// means the target will need to handle MI in EmitInstruction. 467static bool EmitDebugValueComment(const MachineInstr *MI, AsmPrinter &AP) { 468 // This code handles only the 3-operand target-independent form. 469 if (MI->getNumOperands() != 3) 470 return false; 471 472 SmallString<128> Str; 473 raw_svector_ostream OS(Str); 474 OS << '\t' << AP.MAI->getCommentString() << "DEBUG_VALUE: "; 475 476 // cast away const; DIetc do not take const operands for some reason. 477 DIVariable V(const_cast<MDNode*>(MI->getOperand(2).getMetadata())); 478 OS << V.getName() << " <- "; 479 480 // Register or immediate value. Register 0 means undef. 481 if (MI->getOperand(0).isFPImm()) { 482 APFloat APF = APFloat(MI->getOperand(0).getFPImm()->getValueAPF()); 483 if (MI->getOperand(0).getFPImm()->getType()->isFloatTy()) { 484 OS << (double)APF.convertToFloat(); 485 } else if (MI->getOperand(0).getFPImm()->getType()->isDoubleTy()) { 486 OS << APF.convertToDouble(); 487 } else { 488 // There is no good way to print long double. Convert a copy to 489 // double. Ah well, it's only a comment. 490 bool ignored; 491 APF.convert(APFloat::IEEEdouble, APFloat::rmNearestTiesToEven, 492 &ignored); 493 OS << "(long double) " << APF.convertToDouble(); 494 } 495 } else if (MI->getOperand(0).isImm()) { 496 OS << MI->getOperand(0).getImm(); 497 } else { 498 assert(MI->getOperand(0).isReg() && "Unknown operand type"); 499 if (MI->getOperand(0).getReg() == 0) { 500 // Suppress offset, it is not meaningful here. 501 OS << "undef"; 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 OS << AP.TM.getRegisterInfo()->getName(MI->getOperand(0).getReg()); 507 } 508 509 OS << '+' << MI->getOperand(1).getImm(); 510 // NOTE: Want this comment at start of line, don't emit with AddComment. 511 AP.OutStreamer.EmitRawText(OS.str()); 512 return true; 513} 514 515/// EmitFunctionBody - This method emits the body and trailer for a 516/// function. 517void AsmPrinter::EmitFunctionBody() { 518 // Emit target-specific gunk before the function body. 519 EmitFunctionBodyStart(); 520 521 bool ShouldPrintDebugScopes = DD && MMI->hasDebugInfo(); 522 523 // Print out code for the function. 524 bool HasAnyRealCode = false; 525 for (MachineFunction::const_iterator I = MF->begin(), E = MF->end(); 526 I != E; ++I) { 527 // Print a label for the basic block. 528 EmitBasicBlockStart(I); 529 for (MachineBasicBlock::const_iterator II = I->begin(), IE = I->end(); 530 II != IE; ++II) { 531 // Print the assembly for the instruction. 532 if (!II->isLabel()) 533 HasAnyRealCode = true; 534 535 ++EmittedInsts; 536 537 if (ShouldPrintDebugScopes) { 538 if (TimePassesIsEnabled) { 539 NamedRegionTimer T(DbgTimerName, DWARFGroupName); 540 DD->beginScope(II); 541 } else { 542 DD->beginScope(II); 543 } 544 } 545 546 if (isVerbose()) 547 EmitComments(*II, OutStreamer.GetCommentOS()); 548 549 switch (II->getOpcode()) { 550 case TargetOpcode::DBG_LABEL: 551 case TargetOpcode::EH_LABEL: 552 case TargetOpcode::GC_LABEL: 553 OutStreamer.EmitLabel(II->getOperand(0).getMCSymbol()); 554 break; 555 case TargetOpcode::INLINEASM: 556 EmitInlineAsm(II); 557 break; 558 case TargetOpcode::DBG_VALUE: 559 if (isVerbose()) { 560 if (!EmitDebugValueComment(II, *this)) 561 EmitInstruction(II); 562 } 563 break; 564 case TargetOpcode::IMPLICIT_DEF: 565 if (isVerbose()) EmitImplicitDef(II, *this); 566 break; 567 case TargetOpcode::KILL: 568 if (isVerbose()) EmitKill(II, *this); 569 break; 570 default: 571 EmitInstruction(II); 572 break; 573 } 574 575 if (ShouldPrintDebugScopes) { 576 if (TimePassesIsEnabled) { 577 NamedRegionTimer T(DbgTimerName, DWARFGroupName); 578 DD->endScope(II); 579 } else { 580 DD->endScope(II); 581 } 582 } 583 } 584 } 585 586 // If the function is empty and the object file uses .subsections_via_symbols, 587 // then we need to emit *something* to the function body to prevent the 588 // labels from collapsing together. Just emit a 0 byte. 589 if (MAI->hasSubsectionsViaSymbols() && !HasAnyRealCode) 590 OutStreamer.EmitIntValue(0, 1, 0/*addrspace*/); 591 592 // Emit target-specific gunk after the function body. 593 EmitFunctionBodyEnd(); 594 595 // If the target wants a .size directive for the size of the function, emit 596 // it. 597 if (MAI->hasDotTypeDotSizeDirective()) { 598 // Create a symbol for the end of function, so we can get the size as 599 // difference between the function label and the temp label. 600 MCSymbol *FnEndLabel = OutContext.CreateTempSymbol(); 601 OutStreamer.EmitLabel(FnEndLabel); 602 603 const MCExpr *SizeExp = 604 MCBinaryExpr::CreateSub(MCSymbolRefExpr::Create(FnEndLabel, OutContext), 605 MCSymbolRefExpr::Create(CurrentFnSym, OutContext), 606 OutContext); 607 OutStreamer.EmitELFSize(CurrentFnSym, SizeExp); 608 } 609 610 // Emit post-function debug information. 611 if (DD) { 612 if (TimePassesIsEnabled) { 613 NamedRegionTimer T(DbgTimerName, DWARFGroupName); 614 DD->endFunction(MF); 615 } else { 616 DD->endFunction(MF); 617 } 618 } 619 if (DE) { 620 if (TimePassesIsEnabled) { 621 NamedRegionTimer T(EHTimerName, DWARFGroupName); 622 DE->EndFunction(); 623 } else { 624 DE->EndFunction(); 625 } 626 } 627 MMI->EndFunction(); 628 629 // Print out jump tables referenced by the function. 630 EmitJumpTableInfo(); 631 632 OutStreamer.AddBlankLine(); 633} 634 635 636bool AsmPrinter::doFinalization(Module &M) { 637 // Emit global variables. 638 for (Module::const_global_iterator I = M.global_begin(), E = M.global_end(); 639 I != E; ++I) 640 EmitGlobalVariable(I); 641 642 // Finalize debug and EH information. 643 if (DE) { 644 if (TimePassesIsEnabled) { 645 NamedRegionTimer T(EHTimerName, DWARFGroupName); 646 DE->EndModule(); 647 } else { 648 DE->EndModule(); 649 } 650 delete DE; DE = 0; 651 } 652 if (DD) { 653 if (TimePassesIsEnabled) { 654 NamedRegionTimer T(DbgTimerName, DWARFGroupName); 655 DD->endModule(); 656 } else { 657 DD->endModule(); 658 } 659 delete DD; DD = 0; 660 } 661 662 // If the target wants to know about weak references, print them all. 663 if (MAI->getWeakRefDirective()) { 664 // FIXME: This is not lazy, it would be nice to only print weak references 665 // to stuff that is actually used. Note that doing so would require targets 666 // to notice uses in operands (due to constant exprs etc). This should 667 // happen with the MC stuff eventually. 668 669 // Print out module-level global variables here. 670 for (Module::const_global_iterator I = M.global_begin(), E = M.global_end(); 671 I != E; ++I) { 672 if (!I->hasExternalWeakLinkage()) continue; 673 OutStreamer.EmitSymbolAttribute(Mang->getSymbol(I), MCSA_WeakReference); 674 } 675 676 for (Module::const_iterator I = M.begin(), E = M.end(); I != E; ++I) { 677 if (!I->hasExternalWeakLinkage()) continue; 678 OutStreamer.EmitSymbolAttribute(Mang->getSymbol(I), MCSA_WeakReference); 679 } 680 } 681 682 if (MAI->hasSetDirective()) { 683 OutStreamer.AddBlankLine(); 684 for (Module::const_alias_iterator I = M.alias_begin(), E = M.alias_end(); 685 I != E; ++I) { 686 MCSymbol *Name = Mang->getSymbol(I); 687 688 const GlobalValue *GV = cast<GlobalValue>(I->getAliasedGlobal()); 689 MCSymbol *Target = Mang->getSymbol(GV); 690 691 if (I->hasExternalLinkage() || !MAI->getWeakRefDirective()) 692 OutStreamer.EmitSymbolAttribute(Name, MCSA_Global); 693 else if (I->hasWeakLinkage()) 694 OutStreamer.EmitSymbolAttribute(Name, MCSA_WeakReference); 695 else 696 assert(I->hasLocalLinkage() && "Invalid alias linkage"); 697 698 EmitVisibility(Name, I->getVisibility()); 699 700 // Emit the directives as assignments aka .set: 701 OutStreamer.EmitAssignment(Name, 702 MCSymbolRefExpr::Create(Target, OutContext)); 703 } 704 } 705 706 GCModuleInfo *MI = getAnalysisIfAvailable<GCModuleInfo>(); 707 assert(MI && "AsmPrinter didn't require GCModuleInfo?"); 708 for (GCModuleInfo::iterator I = MI->end(), E = MI->begin(); I != E; ) 709 if (GCMetadataPrinter *MP = GetOrCreateGCPrinter(*--I)) 710 MP->finishAssembly(*this); 711 712 // If we don't have any trampolines, then we don't require stack memory 713 // to be executable. Some targets have a directive to declare this. 714 Function *InitTrampolineIntrinsic = M.getFunction("llvm.init.trampoline"); 715 if (!InitTrampolineIntrinsic || InitTrampolineIntrinsic->use_empty()) 716 if (const MCSection *S = MAI->getNonexecutableStackSection(OutContext)) 717 OutStreamer.SwitchSection(S); 718 719 // Allow the target to emit any magic that it wants at the end of the file, 720 // after everything else has gone out. 721 EmitEndOfAsmFile(M); 722 723 delete Mang; Mang = 0; 724 MMI = 0; 725 726 OutStreamer.Finish(); 727 return false; 728} 729 730void AsmPrinter::SetupMachineFunction(MachineFunction &MF) { 731 this->MF = &MF; 732 // Get the function symbol. 733 CurrentFnSym = Mang->getSymbol(MF.getFunction()); 734 735 if (isVerbose()) 736 LI = &getAnalysis<MachineLoopInfo>(); 737} 738 739namespace { 740 // SectionCPs - Keep track the alignment, constpool entries per Section. 741 struct SectionCPs { 742 const MCSection *S; 743 unsigned Alignment; 744 SmallVector<unsigned, 4> CPEs; 745 SectionCPs(const MCSection *s, unsigned a) : S(s), Alignment(a) {} 746 }; 747} 748 749/// EmitConstantPool - Print to the current output stream assembly 750/// representations of the constants in the constant pool MCP. This is 751/// used to print out constants which have been "spilled to memory" by 752/// the code generator. 753/// 754void AsmPrinter::EmitConstantPool() { 755 const MachineConstantPool *MCP = MF->getConstantPool(); 756 const std::vector<MachineConstantPoolEntry> &CP = MCP->getConstants(); 757 if (CP.empty()) return; 758 759 // Calculate sections for constant pool entries. We collect entries to go into 760 // the same section together to reduce amount of section switch statements. 761 SmallVector<SectionCPs, 4> CPSections; 762 for (unsigned i = 0, e = CP.size(); i != e; ++i) { 763 const MachineConstantPoolEntry &CPE = CP[i]; 764 unsigned Align = CPE.getAlignment(); 765 766 SectionKind Kind; 767 switch (CPE.getRelocationInfo()) { 768 default: llvm_unreachable("Unknown section kind"); 769 case 2: Kind = SectionKind::getReadOnlyWithRel(); break; 770 case 1: 771 Kind = SectionKind::getReadOnlyWithRelLocal(); 772 break; 773 case 0: 774 switch (TM.getTargetData()->getTypeAllocSize(CPE.getType())) { 775 case 4: Kind = SectionKind::getMergeableConst4(); break; 776 case 8: Kind = SectionKind::getMergeableConst8(); break; 777 case 16: Kind = SectionKind::getMergeableConst16();break; 778 default: Kind = SectionKind::getMergeableConst(); break; 779 } 780 } 781 782 const MCSection *S = getObjFileLowering().getSectionForConstant(Kind); 783 784 // The number of sections are small, just do a linear search from the 785 // last section to the first. 786 bool Found = false; 787 unsigned SecIdx = CPSections.size(); 788 while (SecIdx != 0) { 789 if (CPSections[--SecIdx].S == S) { 790 Found = true; 791 break; 792 } 793 } 794 if (!Found) { 795 SecIdx = CPSections.size(); 796 CPSections.push_back(SectionCPs(S, Align)); 797 } 798 799 if (Align > CPSections[SecIdx].Alignment) 800 CPSections[SecIdx].Alignment = Align; 801 CPSections[SecIdx].CPEs.push_back(i); 802 } 803 804 // Now print stuff into the calculated sections. 805 for (unsigned i = 0, e = CPSections.size(); i != e; ++i) { 806 OutStreamer.SwitchSection(CPSections[i].S); 807 EmitAlignment(Log2_32(CPSections[i].Alignment)); 808 809 unsigned Offset = 0; 810 for (unsigned j = 0, ee = CPSections[i].CPEs.size(); j != ee; ++j) { 811 unsigned CPI = CPSections[i].CPEs[j]; 812 MachineConstantPoolEntry CPE = CP[CPI]; 813 814 // Emit inter-object padding for alignment. 815 unsigned AlignMask = CPE.getAlignment() - 1; 816 unsigned NewOffset = (Offset + AlignMask) & ~AlignMask; 817 OutStreamer.EmitFill(NewOffset - Offset, 0/*fillval*/, 0/*addrspace*/); 818 819 const Type *Ty = CPE.getType(); 820 Offset = NewOffset + TM.getTargetData()->getTypeAllocSize(Ty); 821 822 // Emit the label with a comment on it. 823 if (isVerbose()) { 824 OutStreamer.GetCommentOS() << "constant pool "; 825 WriteTypeSymbolic(OutStreamer.GetCommentOS(), CPE.getType(), 826 MF->getFunction()->getParent()); 827 OutStreamer.GetCommentOS() << '\n'; 828 } 829 OutStreamer.EmitLabel(GetCPISymbol(CPI)); 830 831 if (CPE.isMachineConstantPoolEntry()) 832 EmitMachineConstantPoolValue(CPE.Val.MachineCPVal); 833 else 834 EmitGlobalConstant(CPE.Val.ConstVal); 835 } 836 } 837} 838 839/// EmitJumpTableInfo - Print assembly representations of the jump tables used 840/// by the current function to the current output stream. 841/// 842void AsmPrinter::EmitJumpTableInfo() { 843 const MachineJumpTableInfo *MJTI = MF->getJumpTableInfo(); 844 if (MJTI == 0) return; 845 if (MJTI->getEntryKind() == MachineJumpTableInfo::EK_Inline) return; 846 const std::vector<MachineJumpTableEntry> &JT = MJTI->getJumpTables(); 847 if (JT.empty()) return; 848 849 // Pick the directive to use to print the jump table entries, and switch to 850 // the appropriate section. 851 const Function *F = MF->getFunction(); 852 bool JTInDiffSection = false; 853 if (// In PIC mode, we need to emit the jump table to the same section as the 854 // function body itself, otherwise the label differences won't make sense. 855 // FIXME: Need a better predicate for this: what about custom entries? 856 MJTI->getEntryKind() == MachineJumpTableInfo::EK_LabelDifference32 || 857 // We should also do if the section name is NULL or function is declared 858 // in discardable section 859 // FIXME: this isn't the right predicate, should be based on the MCSection 860 // for the function. 861 F->isWeakForLinker()) { 862 OutStreamer.SwitchSection(getObjFileLowering().SectionForGlobal(F,Mang,TM)); 863 } else { 864 // Otherwise, drop it in the readonly section. 865 const MCSection *ReadOnlySection = 866 getObjFileLowering().getSectionForConstant(SectionKind::getReadOnly()); 867 OutStreamer.SwitchSection(ReadOnlySection); 868 JTInDiffSection = true; 869 } 870 871 EmitAlignment(Log2_32(MJTI->getEntryAlignment(*TM.getTargetData()))); 872 873 for (unsigned JTI = 0, e = JT.size(); JTI != e; ++JTI) { 874 const std::vector<MachineBasicBlock*> &JTBBs = JT[JTI].MBBs; 875 876 // If this jump table was deleted, ignore it. 877 if (JTBBs.empty()) continue; 878 879 // For the EK_LabelDifference32 entry, if the target supports .set, emit a 880 // .set directive for each unique entry. This reduces the number of 881 // relocations the assembler will generate for the jump table. 882 if (MJTI->getEntryKind() == MachineJumpTableInfo::EK_LabelDifference32 && 883 MAI->hasSetDirective()) { 884 SmallPtrSet<const MachineBasicBlock*, 16> EmittedSets; 885 const TargetLowering *TLI = TM.getTargetLowering(); 886 const MCExpr *Base = TLI->getPICJumpTableRelocBaseExpr(MF,JTI,OutContext); 887 for (unsigned ii = 0, ee = JTBBs.size(); ii != ee; ++ii) { 888 const MachineBasicBlock *MBB = JTBBs[ii]; 889 if (!EmittedSets.insert(MBB)) continue; 890 891 // .set LJTSet, LBB32-base 892 const MCExpr *LHS = 893 MCSymbolRefExpr::Create(MBB->getSymbol(), OutContext); 894 OutStreamer.EmitAssignment(GetJTSetSymbol(JTI, MBB->getNumber()), 895 MCBinaryExpr::CreateSub(LHS, Base, OutContext)); 896 } 897 } 898 899 // On some targets (e.g. Darwin) we want to emit two consequtive labels 900 // before each jump table. The first label is never referenced, but tells 901 // the assembler and linker the extents of the jump table object. The 902 // second label is actually referenced by the code. 903 if (JTInDiffSection && MAI->getLinkerPrivateGlobalPrefix()[0]) 904 // FIXME: This doesn't have to have any specific name, just any randomly 905 // named and numbered 'l' label would work. Simplify GetJTISymbol. 906 OutStreamer.EmitLabel(GetJTISymbol(JTI, true)); 907 908 OutStreamer.EmitLabel(GetJTISymbol(JTI)); 909 910 for (unsigned ii = 0, ee = JTBBs.size(); ii != ee; ++ii) 911 EmitJumpTableEntry(MJTI, JTBBs[ii], JTI); 912 } 913} 914 915/// EmitJumpTableEntry - Emit a jump table entry for the specified MBB to the 916/// current stream. 917void AsmPrinter::EmitJumpTableEntry(const MachineJumpTableInfo *MJTI, 918 const MachineBasicBlock *MBB, 919 unsigned UID) const { 920 const MCExpr *Value = 0; 921 switch (MJTI->getEntryKind()) { 922 case MachineJumpTableInfo::EK_Inline: 923 llvm_unreachable("Cannot emit EK_Inline jump table entry"); break; 924 case MachineJumpTableInfo::EK_Custom32: 925 Value = TM.getTargetLowering()->LowerCustomJumpTableEntry(MJTI, MBB, UID, 926 OutContext); 927 break; 928 case MachineJumpTableInfo::EK_BlockAddress: 929 // EK_BlockAddress - Each entry is a plain address of block, e.g.: 930 // .word LBB123 931 Value = MCSymbolRefExpr::Create(MBB->getSymbol(), OutContext); 932 break; 933 case MachineJumpTableInfo::EK_GPRel32BlockAddress: { 934 // EK_GPRel32BlockAddress - Each entry is an address of block, encoded 935 // with a relocation as gp-relative, e.g.: 936 // .gprel32 LBB123 937 MCSymbol *MBBSym = MBB->getSymbol(); 938 OutStreamer.EmitGPRel32Value(MCSymbolRefExpr::Create(MBBSym, OutContext)); 939 return; 940 } 941 942 case MachineJumpTableInfo::EK_LabelDifference32: { 943 // EK_LabelDifference32 - Each entry is the address of the block minus 944 // the address of the jump table. This is used for PIC jump tables where 945 // gprel32 is not supported. e.g.: 946 // .word LBB123 - LJTI1_2 947 // If the .set directive is supported, this is emitted as: 948 // .set L4_5_set_123, LBB123 - LJTI1_2 949 // .word L4_5_set_123 950 951 // If we have emitted set directives for the jump table entries, print 952 // them rather than the entries themselves. If we're emitting PIC, then 953 // emit the table entries as differences between two text section labels. 954 if (MAI->hasSetDirective()) { 955 // If we used .set, reference the .set's symbol. 956 Value = MCSymbolRefExpr::Create(GetJTSetSymbol(UID, MBB->getNumber()), 957 OutContext); 958 break; 959 } 960 // Otherwise, use the difference as the jump table entry. 961 Value = MCSymbolRefExpr::Create(MBB->getSymbol(), OutContext); 962 const MCExpr *JTI = MCSymbolRefExpr::Create(GetJTISymbol(UID), OutContext); 963 Value = MCBinaryExpr::CreateSub(Value, JTI, OutContext); 964 break; 965 } 966 } 967 968 assert(Value && "Unknown entry kind!"); 969 970 unsigned EntrySize = MJTI->getEntrySize(*TM.getTargetData()); 971 OutStreamer.EmitValue(Value, EntrySize, /*addrspace*/0); 972} 973 974 975/// EmitSpecialLLVMGlobal - Check to see if the specified global is a 976/// special global used by LLVM. If so, emit it and return true, otherwise 977/// do nothing and return false. 978bool AsmPrinter::EmitSpecialLLVMGlobal(const GlobalVariable *GV) { 979 if (GV->getName() == "llvm.used") { 980 if (MAI->hasNoDeadStrip()) // No need to emit this at all. 981 EmitLLVMUsedList(GV->getInitializer()); 982 return true; 983 } 984 985 // Ignore debug and non-emitted data. This handles llvm.compiler.used. 986 if (GV->getSection() == "llvm.metadata" || 987 GV->hasAvailableExternallyLinkage()) 988 return true; 989 990 if (!GV->hasAppendingLinkage()) return false; 991 992 assert(GV->hasInitializer() && "Not a special LLVM global!"); 993 994 const TargetData *TD = TM.getTargetData(); 995 unsigned Align = Log2_32(TD->getPointerPrefAlignment()); 996 if (GV->getName() == "llvm.global_ctors") { 997 OutStreamer.SwitchSection(getObjFileLowering().getStaticCtorSection()); 998 EmitAlignment(Align, 0); 999 EmitXXStructorList(GV->getInitializer()); 1000 1001 if (TM.getRelocationModel() == Reloc::Static && 1002 MAI->hasStaticCtorDtorReferenceInStaticMode()) { 1003 StringRef Sym(".constructors_used"); 1004 OutStreamer.EmitSymbolAttribute(OutContext.GetOrCreateSymbol(Sym), 1005 MCSA_Reference); 1006 } 1007 return true; 1008 } 1009 1010 if (GV->getName() == "llvm.global_dtors") { 1011 OutStreamer.SwitchSection(getObjFileLowering().getStaticDtorSection()); 1012 EmitAlignment(Align, 0); 1013 EmitXXStructorList(GV->getInitializer()); 1014 1015 if (TM.getRelocationModel() == Reloc::Static && 1016 MAI->hasStaticCtorDtorReferenceInStaticMode()) { 1017 StringRef Sym(".destructors_used"); 1018 OutStreamer.EmitSymbolAttribute(OutContext.GetOrCreateSymbol(Sym), 1019 MCSA_Reference); 1020 } 1021 return true; 1022 } 1023 1024 return false; 1025} 1026 1027/// EmitLLVMUsedList - For targets that define a MAI::UsedDirective, mark each 1028/// global in the specified llvm.used list for which emitUsedDirectiveFor 1029/// is true, as being used with this directive. 1030void AsmPrinter::EmitLLVMUsedList(Constant *List) { 1031 // Should be an array of 'i8*'. 1032 ConstantArray *InitList = dyn_cast<ConstantArray>(List); 1033 if (InitList == 0) return; 1034 1035 for (unsigned i = 0, e = InitList->getNumOperands(); i != e; ++i) { 1036 const GlobalValue *GV = 1037 dyn_cast<GlobalValue>(InitList->getOperand(i)->stripPointerCasts()); 1038 if (GV && getObjFileLowering().shouldEmitUsedDirectiveFor(GV, Mang)) 1039 OutStreamer.EmitSymbolAttribute(Mang->getSymbol(GV), MCSA_NoDeadStrip); 1040 } 1041} 1042 1043/// EmitXXStructorList - Emit the ctor or dtor list. This just prints out the 1044/// function pointers, ignoring the init priority. 1045void AsmPrinter::EmitXXStructorList(Constant *List) { 1046 // Should be an array of '{ int, void ()* }' structs. The first value is the 1047 // init priority, which we ignore. 1048 if (!isa<ConstantArray>(List)) return; 1049 ConstantArray *InitList = cast<ConstantArray>(List); 1050 for (unsigned i = 0, e = InitList->getNumOperands(); i != e; ++i) 1051 if (ConstantStruct *CS = dyn_cast<ConstantStruct>(InitList->getOperand(i))){ 1052 if (CS->getNumOperands() != 2) return; // Not array of 2-element structs. 1053 1054 if (CS->getOperand(1)->isNullValue()) 1055 return; // Found a null terminator, exit printing. 1056 // Emit the function pointer. 1057 EmitGlobalConstant(CS->getOperand(1)); 1058 } 1059} 1060 1061//===--------------------------------------------------------------------===// 1062// Emission and print routines 1063// 1064 1065/// EmitInt8 - Emit a byte directive and value. 1066/// 1067void AsmPrinter::EmitInt8(int Value) const { 1068 OutStreamer.EmitIntValue(Value, 1, 0/*addrspace*/); 1069} 1070 1071/// EmitInt16 - Emit a short directive and value. 1072/// 1073void AsmPrinter::EmitInt16(int Value) const { 1074 OutStreamer.EmitIntValue(Value, 2, 0/*addrspace*/); 1075} 1076 1077/// EmitInt32 - Emit a long directive and value. 1078/// 1079void AsmPrinter::EmitInt32(int Value) const { 1080 OutStreamer.EmitIntValue(Value, 4, 0/*addrspace*/); 1081} 1082 1083/// EmitLabelDifference - Emit something like ".long Hi-Lo" where the size 1084/// in bytes of the directive is specified by Size and Hi/Lo specify the 1085/// labels. This implicitly uses .set if it is available. 1086void AsmPrinter::EmitLabelDifference(const MCSymbol *Hi, const MCSymbol *Lo, 1087 unsigned Size) const { 1088 // Get the Hi-Lo expression. 1089 const MCExpr *Diff = 1090 MCBinaryExpr::CreateSub(MCSymbolRefExpr::Create(Hi, OutContext), 1091 MCSymbolRefExpr::Create(Lo, OutContext), 1092 OutContext); 1093 1094 if (!MAI->hasSetDirective()) { 1095 OutStreamer.EmitValue(Diff, Size, 0/*AddrSpace*/); 1096 return; 1097 } 1098 1099 // Otherwise, emit with .set (aka assignment). 1100 MCSymbol *SetLabel = GetTempSymbol("set", SetCounter++); 1101 OutStreamer.EmitAssignment(SetLabel, Diff); 1102 OutStreamer.EmitSymbolValue(SetLabel, Size, 0/*AddrSpace*/); 1103} 1104 1105/// EmitLabelOffsetDifference - Emit something like ".long Hi+Offset-Lo" 1106/// where the size in bytes of the directive is specified by Size and Hi/Lo 1107/// specify the labels. This implicitly uses .set if it is available. 1108void AsmPrinter::EmitLabelOffsetDifference(const MCSymbol *Hi, uint64_t Offset, 1109 const MCSymbol *Lo, unsigned Size) 1110 const { 1111 1112 // Emit Hi+Offset - Lo 1113 // Get the Hi+Offset expression. 1114 const MCExpr *Plus = 1115 MCBinaryExpr::CreateAdd(MCSymbolRefExpr::Create(Hi, OutContext), 1116 MCConstantExpr::Create(Offset, OutContext), 1117 OutContext); 1118 1119 // Get the Hi+Offset-Lo expression. 1120 const MCExpr *Diff = 1121 MCBinaryExpr::CreateSub(Plus, 1122 MCSymbolRefExpr::Create(Lo, OutContext), 1123 OutContext); 1124 1125 if (!MAI->hasSetDirective()) 1126 OutStreamer.EmitValue(Diff, 4, 0/*AddrSpace*/); 1127 else { 1128 // Otherwise, emit with .set (aka assignment). 1129 MCSymbol *SetLabel = GetTempSymbol("set", SetCounter++); 1130 OutStreamer.EmitAssignment(SetLabel, Diff); 1131 OutStreamer.EmitSymbolValue(SetLabel, 4, 0/*AddrSpace*/); 1132 } 1133} 1134 1135 1136//===----------------------------------------------------------------------===// 1137 1138// EmitAlignment - Emit an alignment directive to the specified power of 1139// two boundary. For example, if you pass in 3 here, you will get an 8 1140// byte alignment. If a global value is specified, and if that global has 1141// an explicit alignment requested, it will unconditionally override the 1142// alignment request. However, if ForcedAlignBits is specified, this value 1143// has final say: the ultimate alignment will be the max of ForcedAlignBits 1144// and the alignment computed with NumBits and the global. 1145// 1146// The algorithm is: 1147// Align = NumBits; 1148// if (GV && GV->hasalignment) Align = GV->getalignment(); 1149// Align = std::max(Align, ForcedAlignBits); 1150// 1151void AsmPrinter::EmitAlignment(unsigned NumBits, const GlobalValue *GV, 1152 unsigned ForcedAlignBits, 1153 bool UseFillExpr) const { 1154 if (GV && GV->getAlignment()) 1155 NumBits = Log2_32(GV->getAlignment()); 1156 NumBits = std::max(NumBits, ForcedAlignBits); 1157 1158 if (NumBits == 0) return; // No need to emit alignment. 1159 1160 if (getCurrentSection()->getKind().isText()) 1161 OutStreamer.EmitCodeAlignment(1 << NumBits); 1162 else 1163 OutStreamer.EmitValueToAlignment(1 << NumBits, 0, 1, 0); 1164} 1165 1166//===----------------------------------------------------------------------===// 1167// Constant emission. 1168//===----------------------------------------------------------------------===// 1169 1170/// LowerConstant - Lower the specified LLVM Constant to an MCExpr. 1171/// 1172static const MCExpr *LowerConstant(const Constant *CV, AsmPrinter &AP) { 1173 MCContext &Ctx = AP.OutContext; 1174 1175 if (CV->isNullValue() || isa<UndefValue>(CV)) 1176 return MCConstantExpr::Create(0, Ctx); 1177 1178 if (const ConstantInt *CI = dyn_cast<ConstantInt>(CV)) 1179 return MCConstantExpr::Create(CI->getZExtValue(), Ctx); 1180 1181 if (const GlobalValue *GV = dyn_cast<GlobalValue>(CV)) 1182 return MCSymbolRefExpr::Create(AP.Mang->getSymbol(GV), Ctx); 1183 if (const BlockAddress *BA = dyn_cast<BlockAddress>(CV)) 1184 return MCSymbolRefExpr::Create(AP.GetBlockAddressSymbol(BA), Ctx); 1185 1186 const ConstantExpr *CE = dyn_cast<ConstantExpr>(CV); 1187 if (CE == 0) { 1188 llvm_unreachable("Unknown constant value to lower!"); 1189 return MCConstantExpr::Create(0, Ctx); 1190 } 1191 1192 switch (CE->getOpcode()) { 1193 default: 1194 // If the code isn't optimized, there may be outstanding folding 1195 // opportunities. Attempt to fold the expression using TargetData as a 1196 // last resort before giving up. 1197 if (Constant *C = 1198 ConstantFoldConstantExpression(CE, AP.TM.getTargetData())) 1199 if (C != CE) 1200 return LowerConstant(C, AP); 1201#ifndef NDEBUG 1202 CE->dump(); 1203#endif 1204 llvm_unreachable("FIXME: Don't support this constant expr"); 1205 case Instruction::GetElementPtr: { 1206 const TargetData &TD = *AP.TM.getTargetData(); 1207 // Generate a symbolic expression for the byte address 1208 const Constant *PtrVal = CE->getOperand(0); 1209 SmallVector<Value*, 8> IdxVec(CE->op_begin()+1, CE->op_end()); 1210 int64_t Offset = TD.getIndexedOffset(PtrVal->getType(), &IdxVec[0], 1211 IdxVec.size()); 1212 1213 const MCExpr *Base = LowerConstant(CE->getOperand(0), AP); 1214 if (Offset == 0) 1215 return Base; 1216 1217 // Truncate/sext the offset to the pointer size. 1218 if (TD.getPointerSizeInBits() != 64) { 1219 int SExtAmount = 64-TD.getPointerSizeInBits(); 1220 Offset = (Offset << SExtAmount) >> SExtAmount; 1221 } 1222 1223 return MCBinaryExpr::CreateAdd(Base, MCConstantExpr::Create(Offset, Ctx), 1224 Ctx); 1225 } 1226 1227 case Instruction::Trunc: 1228 // We emit the value and depend on the assembler to truncate the generated 1229 // expression properly. This is important for differences between 1230 // blockaddress labels. Since the two labels are in the same function, it 1231 // is reasonable to treat their delta as a 32-bit value. 1232 // FALL THROUGH. 1233 case Instruction::BitCast: 1234 return LowerConstant(CE->getOperand(0), AP); 1235 1236 case Instruction::IntToPtr: { 1237 const TargetData &TD = *AP.TM.getTargetData(); 1238 // Handle casts to pointers by changing them into casts to the appropriate 1239 // integer type. This promotes constant folding and simplifies this code. 1240 Constant *Op = CE->getOperand(0); 1241 Op = ConstantExpr::getIntegerCast(Op, TD.getIntPtrType(CV->getContext()), 1242 false/*ZExt*/); 1243 return LowerConstant(Op, AP); 1244 } 1245 1246 case Instruction::PtrToInt: { 1247 const TargetData &TD = *AP.TM.getTargetData(); 1248 // Support only foldable casts to/from pointers that can be eliminated by 1249 // changing the pointer to the appropriately sized integer type. 1250 Constant *Op = CE->getOperand(0); 1251 const Type *Ty = CE->getType(); 1252 1253 const MCExpr *OpExpr = LowerConstant(Op, AP); 1254 1255 // We can emit the pointer value into this slot if the slot is an 1256 // integer slot equal to the size of the pointer. 1257 if (TD.getTypeAllocSize(Ty) == TD.getTypeAllocSize(Op->getType())) 1258 return OpExpr; 1259 1260 // Otherwise the pointer is smaller than the resultant integer, mask off 1261 // the high bits so we are sure to get a proper truncation if the input is 1262 // a constant expr. 1263 unsigned InBits = TD.getTypeAllocSizeInBits(Op->getType()); 1264 const MCExpr *MaskExpr = MCConstantExpr::Create(~0ULL >> (64-InBits), Ctx); 1265 return MCBinaryExpr::CreateAnd(OpExpr, MaskExpr, Ctx); 1266 } 1267 1268 // The MC library also has a right-shift operator, but it isn't consistently 1269 // signed or unsigned between different targets. 1270 case Instruction::Add: 1271 case Instruction::Sub: 1272 case Instruction::Mul: 1273 case Instruction::SDiv: 1274 case Instruction::SRem: 1275 case Instruction::Shl: 1276 case Instruction::And: 1277 case Instruction::Or: 1278 case Instruction::Xor: { 1279 const MCExpr *LHS = LowerConstant(CE->getOperand(0), AP); 1280 const MCExpr *RHS = LowerConstant(CE->getOperand(1), AP); 1281 switch (CE->getOpcode()) { 1282 default: llvm_unreachable("Unknown binary operator constant cast expr"); 1283 case Instruction::Add: return MCBinaryExpr::CreateAdd(LHS, RHS, Ctx); 1284 case Instruction::Sub: return MCBinaryExpr::CreateSub(LHS, RHS, Ctx); 1285 case Instruction::Mul: return MCBinaryExpr::CreateMul(LHS, RHS, Ctx); 1286 case Instruction::SDiv: return MCBinaryExpr::CreateDiv(LHS, RHS, Ctx); 1287 case Instruction::SRem: return MCBinaryExpr::CreateMod(LHS, RHS, Ctx); 1288 case Instruction::Shl: return MCBinaryExpr::CreateShl(LHS, RHS, Ctx); 1289 case Instruction::And: return MCBinaryExpr::CreateAnd(LHS, RHS, Ctx); 1290 case Instruction::Or: return MCBinaryExpr::CreateOr (LHS, RHS, Ctx); 1291 case Instruction::Xor: return MCBinaryExpr::CreateXor(LHS, RHS, Ctx); 1292 } 1293 } 1294 } 1295} 1296 1297static void EmitGlobalConstantImpl(const Constant *C, unsigned AddrSpace, 1298 AsmPrinter &AP); 1299 1300static void EmitGlobalConstantArray(const ConstantArray *CA, unsigned AddrSpace, 1301 AsmPrinter &AP) { 1302 if (AddrSpace != 0 || !CA->isString()) { 1303 // Not a string. Print the values in successive locations 1304 for (unsigned i = 0, e = CA->getNumOperands(); i != e; ++i) 1305 EmitGlobalConstantImpl(CA->getOperand(i), AddrSpace, AP); 1306 return; 1307 } 1308 1309 // Otherwise, it can be emitted as .ascii. 1310 SmallVector<char, 128> TmpVec; 1311 TmpVec.reserve(CA->getNumOperands()); 1312 for (unsigned i = 0, e = CA->getNumOperands(); i != e; ++i) 1313 TmpVec.push_back(cast<ConstantInt>(CA->getOperand(i))->getZExtValue()); 1314 1315 AP.OutStreamer.EmitBytes(StringRef(TmpVec.data(), TmpVec.size()), AddrSpace); 1316} 1317 1318static void EmitGlobalConstantVector(const ConstantVector *CV, 1319 unsigned AddrSpace, AsmPrinter &AP) { 1320 for (unsigned i = 0, e = CV->getType()->getNumElements(); i != e; ++i) 1321 EmitGlobalConstantImpl(CV->getOperand(i), AddrSpace, AP); 1322} 1323 1324static void EmitGlobalConstantStruct(const ConstantStruct *CS, 1325 unsigned AddrSpace, AsmPrinter &AP) { 1326 // Print the fields in successive locations. Pad to align if needed! 1327 const TargetData *TD = AP.TM.getTargetData(); 1328 unsigned Size = TD->getTypeAllocSize(CS->getType()); 1329 const StructLayout *Layout = TD->getStructLayout(CS->getType()); 1330 uint64_t SizeSoFar = 0; 1331 for (unsigned i = 0, e = CS->getNumOperands(); i != e; ++i) { 1332 const Constant *Field = CS->getOperand(i); 1333 1334 // Check if padding is needed and insert one or more 0s. 1335 uint64_t FieldSize = TD->getTypeAllocSize(Field->getType()); 1336 uint64_t PadSize = ((i == e-1 ? Size : Layout->getElementOffset(i+1)) 1337 - Layout->getElementOffset(i)) - FieldSize; 1338 SizeSoFar += FieldSize + PadSize; 1339 1340 // Now print the actual field value. 1341 EmitGlobalConstantImpl(Field, AddrSpace, AP); 1342 1343 // Insert padding - this may include padding to increase the size of the 1344 // current field up to the ABI size (if the struct is not packed) as well 1345 // as padding to ensure that the next field starts at the right offset. 1346 AP.OutStreamer.EmitZeros(PadSize, AddrSpace); 1347 } 1348 assert(SizeSoFar == Layout->getSizeInBytes() && 1349 "Layout of constant struct may be incorrect!"); 1350} 1351 1352static void EmitGlobalConstantUnion(const ConstantUnion *CU, 1353 unsigned AddrSpace, AsmPrinter &AP) { 1354 const TargetData *TD = AP.TM.getTargetData(); 1355 unsigned Size = TD->getTypeAllocSize(CU->getType()); 1356 1357 const Constant *Contents = CU->getOperand(0); 1358 unsigned FilledSize = TD->getTypeAllocSize(Contents->getType()); 1359 1360 // Print the actually filled part 1361 EmitGlobalConstantImpl(Contents, AddrSpace, AP); 1362 1363 // And pad with enough zeroes 1364 AP.OutStreamer.EmitZeros(Size-FilledSize, AddrSpace); 1365} 1366 1367static void EmitGlobalConstantFP(const ConstantFP *CFP, unsigned AddrSpace, 1368 AsmPrinter &AP) { 1369 // FP Constants are printed as integer constants to avoid losing 1370 // precision. 1371 if (CFP->getType()->isDoubleTy()) { 1372 if (AP.isVerbose()) { 1373 double Val = CFP->getValueAPF().convertToDouble(); 1374 AP.OutStreamer.GetCommentOS() << "double " << Val << '\n'; 1375 } 1376 1377 uint64_t Val = CFP->getValueAPF().bitcastToAPInt().getZExtValue(); 1378 AP.OutStreamer.EmitIntValue(Val, 8, AddrSpace); 1379 return; 1380 } 1381 1382 if (CFP->getType()->isFloatTy()) { 1383 if (AP.isVerbose()) { 1384 float Val = CFP->getValueAPF().convertToFloat(); 1385 AP.OutStreamer.GetCommentOS() << "float " << Val << '\n'; 1386 } 1387 uint64_t Val = CFP->getValueAPF().bitcastToAPInt().getZExtValue(); 1388 AP.OutStreamer.EmitIntValue(Val, 4, AddrSpace); 1389 return; 1390 } 1391 1392 if (CFP->getType()->isX86_FP80Ty()) { 1393 // all long double variants are printed as hex 1394 // API needed to prevent premature destruction 1395 APInt API = CFP->getValueAPF().bitcastToAPInt(); 1396 const uint64_t *p = API.getRawData(); 1397 if (AP.isVerbose()) { 1398 // Convert to double so we can print the approximate val as a comment. 1399 APFloat DoubleVal = CFP->getValueAPF(); 1400 bool ignored; 1401 DoubleVal.convert(APFloat::IEEEdouble, APFloat::rmNearestTiesToEven, 1402 &ignored); 1403 AP.OutStreamer.GetCommentOS() << "x86_fp80 ~= " 1404 << DoubleVal.convertToDouble() << '\n'; 1405 } 1406 1407 if (AP.TM.getTargetData()->isBigEndian()) { 1408 AP.OutStreamer.EmitIntValue(p[1], 2, AddrSpace); 1409 AP.OutStreamer.EmitIntValue(p[0], 8, AddrSpace); 1410 } else { 1411 AP.OutStreamer.EmitIntValue(p[0], 8, AddrSpace); 1412 AP.OutStreamer.EmitIntValue(p[1], 2, AddrSpace); 1413 } 1414 1415 // Emit the tail padding for the long double. 1416 const TargetData &TD = *AP.TM.getTargetData(); 1417 AP.OutStreamer.EmitZeros(TD.getTypeAllocSize(CFP->getType()) - 1418 TD.getTypeStoreSize(CFP->getType()), AddrSpace); 1419 return; 1420 } 1421 1422 assert(CFP->getType()->isPPC_FP128Ty() && 1423 "Floating point constant type not handled"); 1424 // All long double variants are printed as hex 1425 // API needed to prevent premature destruction. 1426 APInt API = CFP->getValueAPF().bitcastToAPInt(); 1427 const uint64_t *p = API.getRawData(); 1428 if (AP.TM.getTargetData()->isBigEndian()) { 1429 AP.OutStreamer.EmitIntValue(p[0], 8, AddrSpace); 1430 AP.OutStreamer.EmitIntValue(p[1], 8, AddrSpace); 1431 } else { 1432 AP.OutStreamer.EmitIntValue(p[1], 8, AddrSpace); 1433 AP.OutStreamer.EmitIntValue(p[0], 8, AddrSpace); 1434 } 1435} 1436 1437static void EmitGlobalConstantLargeInt(const ConstantInt *CI, 1438 unsigned AddrSpace, AsmPrinter &AP) { 1439 const TargetData *TD = AP.TM.getTargetData(); 1440 unsigned BitWidth = CI->getBitWidth(); 1441 assert((BitWidth & 63) == 0 && "only support multiples of 64-bits"); 1442 1443 // We don't expect assemblers to support integer data directives 1444 // for more than 64 bits, so we emit the data in at most 64-bit 1445 // quantities at a time. 1446 const uint64_t *RawData = CI->getValue().getRawData(); 1447 for (unsigned i = 0, e = BitWidth / 64; i != e; ++i) { 1448 uint64_t Val = TD->isBigEndian() ? RawData[e - i - 1] : RawData[i]; 1449 AP.OutStreamer.EmitIntValue(Val, 8, AddrSpace); 1450 } 1451} 1452 1453static void EmitGlobalConstantImpl(const Constant *CV, unsigned AddrSpace, 1454 AsmPrinter &AP) { 1455 if (isa<ConstantAggregateZero>(CV) || isa<UndefValue>(CV)) { 1456 uint64_t Size = AP.TM.getTargetData()->getTypeAllocSize(CV->getType()); 1457 return AP.OutStreamer.EmitZeros(Size, AddrSpace); 1458 } 1459 1460 if (const ConstantInt *CI = dyn_cast<ConstantInt>(CV)) { 1461 unsigned Size = AP.TM.getTargetData()->getTypeAllocSize(CV->getType()); 1462 switch (Size) { 1463 case 1: 1464 case 2: 1465 case 4: 1466 case 8: 1467 if (AP.isVerbose()) 1468 AP.OutStreamer.GetCommentOS() << format("0x%llx\n", CI->getZExtValue()); 1469 AP.OutStreamer.EmitIntValue(CI->getZExtValue(), Size, AddrSpace); 1470 return; 1471 default: 1472 EmitGlobalConstantLargeInt(CI, AddrSpace, AP); 1473 return; 1474 } 1475 } 1476 1477 if (const ConstantArray *CVA = dyn_cast<ConstantArray>(CV)) 1478 return EmitGlobalConstantArray(CVA, AddrSpace, AP); 1479 1480 if (const ConstantStruct *CVS = dyn_cast<ConstantStruct>(CV)) 1481 return EmitGlobalConstantStruct(CVS, AddrSpace, AP); 1482 1483 if (const ConstantFP *CFP = dyn_cast<ConstantFP>(CV)) 1484 return EmitGlobalConstantFP(CFP, AddrSpace, AP); 1485 1486 if (isa<ConstantPointerNull>(CV)) { 1487 unsigned Size = AP.TM.getTargetData()->getTypeAllocSize(CV->getType()); 1488 AP.OutStreamer.EmitIntValue(0, Size, AddrSpace); 1489 return; 1490 } 1491 1492 if (const ConstantUnion *CVU = dyn_cast<ConstantUnion>(CV)) 1493 return EmitGlobalConstantUnion(CVU, AddrSpace, AP); 1494 1495 if (const ConstantVector *V = dyn_cast<ConstantVector>(CV)) 1496 return EmitGlobalConstantVector(V, AddrSpace, AP); 1497 1498 // Otherwise, it must be a ConstantExpr. Lower it to an MCExpr, then emit it 1499 // thread the streamer with EmitValue. 1500 AP.OutStreamer.EmitValue(LowerConstant(CV, AP), 1501 AP.TM.getTargetData()->getTypeAllocSize(CV->getType()), 1502 AddrSpace); 1503} 1504 1505/// EmitGlobalConstant - Print a general LLVM constant to the .s file. 1506void AsmPrinter::EmitGlobalConstant(const Constant *CV, unsigned AddrSpace) { 1507 uint64_t Size = TM.getTargetData()->getTypeAllocSize(CV->getType()); 1508 if (Size) 1509 EmitGlobalConstantImpl(CV, AddrSpace, *this); 1510 else if (MAI->hasSubsectionsViaSymbols()) { 1511 // If the global has zero size, emit a single byte so that two labels don't 1512 // look like they are at the same location. 1513 OutStreamer.EmitIntValue(0, 1, AddrSpace); 1514 } 1515} 1516 1517void AsmPrinter::EmitMachineConstantPoolValue(MachineConstantPoolValue *MCPV) { 1518 // Target doesn't support this yet! 1519 llvm_unreachable("Target does not support EmitMachineConstantPoolValue"); 1520} 1521 1522void AsmPrinter::printOffset(int64_t Offset, raw_ostream &OS) const { 1523 if (Offset > 0) 1524 OS << '+' << Offset; 1525 else if (Offset < 0) 1526 OS << Offset; 1527} 1528 1529//===----------------------------------------------------------------------===// 1530// Symbol Lowering Routines. 1531//===----------------------------------------------------------------------===// 1532 1533/// GetTempSymbol - Return the MCSymbol corresponding to the assembler 1534/// temporary label with the specified stem and unique ID. 1535MCSymbol *AsmPrinter::GetTempSymbol(StringRef Name, unsigned ID) const { 1536 return OutContext.GetOrCreateSymbol(Twine(MAI->getPrivateGlobalPrefix()) + 1537 Name + Twine(ID)); 1538} 1539 1540/// GetTempSymbol - Return an assembler temporary label with the specified 1541/// stem. 1542MCSymbol *AsmPrinter::GetTempSymbol(StringRef Name) const { 1543 return OutContext.GetOrCreateSymbol(Twine(MAI->getPrivateGlobalPrefix())+ 1544 Name); 1545} 1546 1547 1548MCSymbol *AsmPrinter::GetBlockAddressSymbol(const BlockAddress *BA) const { 1549 return MMI->getAddrLabelSymbol(BA->getBasicBlock()); 1550} 1551 1552MCSymbol *AsmPrinter::GetBlockAddressSymbol(const BasicBlock *BB) const { 1553 return MMI->getAddrLabelSymbol(BB); 1554} 1555 1556/// GetCPISymbol - Return the symbol for the specified constant pool entry. 1557MCSymbol *AsmPrinter::GetCPISymbol(unsigned CPID) const { 1558 return OutContext.GetOrCreateSymbol 1559 (Twine(MAI->getPrivateGlobalPrefix()) + "CPI" + Twine(getFunctionNumber()) 1560 + "_" + Twine(CPID)); 1561} 1562 1563/// GetJTISymbol - Return the symbol for the specified jump table entry. 1564MCSymbol *AsmPrinter::GetJTISymbol(unsigned JTID, bool isLinkerPrivate) const { 1565 return MF->getJTISymbol(JTID, OutContext, isLinkerPrivate); 1566} 1567 1568/// GetJTSetSymbol - Return the symbol for the specified jump table .set 1569/// FIXME: privatize to AsmPrinter. 1570MCSymbol *AsmPrinter::GetJTSetSymbol(unsigned UID, unsigned MBBID) const { 1571 return OutContext.GetOrCreateSymbol 1572 (Twine(MAI->getPrivateGlobalPrefix()) + Twine(getFunctionNumber()) + "_" + 1573 Twine(UID) + "_set_" + Twine(MBBID)); 1574} 1575 1576/// GetSymbolWithGlobalValueBase - Return the MCSymbol for a symbol with 1577/// global value name as its base, with the specified suffix, and where the 1578/// symbol is forced to have private linkage if ForcePrivate is true. 1579MCSymbol *AsmPrinter::GetSymbolWithGlobalValueBase(const GlobalValue *GV, 1580 StringRef Suffix, 1581 bool ForcePrivate) const { 1582 SmallString<60> NameStr; 1583 Mang->getNameWithPrefix(NameStr, GV, ForcePrivate); 1584 NameStr.append(Suffix.begin(), Suffix.end()); 1585 return OutContext.GetOrCreateSymbol(NameStr.str()); 1586} 1587 1588/// GetExternalSymbolSymbol - Return the MCSymbol for the specified 1589/// ExternalSymbol. 1590MCSymbol *AsmPrinter::GetExternalSymbolSymbol(StringRef Sym) const { 1591 SmallString<60> NameStr; 1592 Mang->getNameWithPrefix(NameStr, Sym); 1593 return OutContext.GetOrCreateSymbol(NameStr.str()); 1594} 1595 1596 1597 1598/// PrintParentLoopComment - Print comments about parent loops of this one. 1599static void PrintParentLoopComment(raw_ostream &OS, const MachineLoop *Loop, 1600 unsigned FunctionNumber) { 1601 if (Loop == 0) return; 1602 PrintParentLoopComment(OS, Loop->getParentLoop(), FunctionNumber); 1603 OS.indent(Loop->getLoopDepth()*2) 1604 << "Parent Loop BB" << FunctionNumber << "_" 1605 << Loop->getHeader()->getNumber() 1606 << " Depth=" << Loop->getLoopDepth() << '\n'; 1607} 1608 1609 1610/// PrintChildLoopComment - Print comments about child loops within 1611/// the loop for this basic block, with nesting. 1612static void PrintChildLoopComment(raw_ostream &OS, const MachineLoop *Loop, 1613 unsigned FunctionNumber) { 1614 // Add child loop information 1615 for (MachineLoop::iterator CL = Loop->begin(), E = Loop->end();CL != E; ++CL){ 1616 OS.indent((*CL)->getLoopDepth()*2) 1617 << "Child Loop BB" << FunctionNumber << "_" 1618 << (*CL)->getHeader()->getNumber() << " Depth " << (*CL)->getLoopDepth() 1619 << '\n'; 1620 PrintChildLoopComment(OS, *CL, FunctionNumber); 1621 } 1622} 1623 1624/// EmitBasicBlockLoopComments - Pretty-print comments for basic blocks. 1625static void EmitBasicBlockLoopComments(const MachineBasicBlock &MBB, 1626 const MachineLoopInfo *LI, 1627 const AsmPrinter &AP) { 1628 // Add loop depth information 1629 const MachineLoop *Loop = LI->getLoopFor(&MBB); 1630 if (Loop == 0) return; 1631 1632 MachineBasicBlock *Header = Loop->getHeader(); 1633 assert(Header && "No header for loop"); 1634 1635 // If this block is not a loop header, just print out what is the loop header 1636 // and return. 1637 if (Header != &MBB) { 1638 AP.OutStreamer.AddComment(" in Loop: Header=BB" + 1639 Twine(AP.getFunctionNumber())+"_" + 1640 Twine(Loop->getHeader()->getNumber())+ 1641 " Depth="+Twine(Loop->getLoopDepth())); 1642 return; 1643 } 1644 1645 // Otherwise, it is a loop header. Print out information about child and 1646 // parent loops. 1647 raw_ostream &OS = AP.OutStreamer.GetCommentOS(); 1648 1649 PrintParentLoopComment(OS, Loop->getParentLoop(), AP.getFunctionNumber()); 1650 1651 OS << "=>"; 1652 OS.indent(Loop->getLoopDepth()*2-2); 1653 1654 OS << "This "; 1655 if (Loop->empty()) 1656 OS << "Inner "; 1657 OS << "Loop Header: Depth=" + Twine(Loop->getLoopDepth()) << '\n'; 1658 1659 PrintChildLoopComment(OS, Loop, AP.getFunctionNumber()); 1660} 1661 1662 1663/// EmitBasicBlockStart - This method prints the label for the specified 1664/// MachineBasicBlock, an alignment (if present) and a comment describing 1665/// it if appropriate. 1666void AsmPrinter::EmitBasicBlockStart(const MachineBasicBlock *MBB) const { 1667 // Emit an alignment directive for this block, if needed. 1668 if (unsigned Align = MBB->getAlignment()) 1669 EmitAlignment(Log2_32(Align)); 1670 1671 // If the block has its address taken, emit any labels that were used to 1672 // reference the block. It is possible that there is more than one label 1673 // here, because multiple LLVM BB's may have been RAUW'd to this block after 1674 // the references were generated. 1675 if (MBB->hasAddressTaken()) { 1676 const BasicBlock *BB = MBB->getBasicBlock(); 1677 if (isVerbose()) 1678 OutStreamer.AddComment("Block address taken"); 1679 1680 std::vector<MCSymbol*> Syms = MMI->getAddrLabelSymbolToEmit(BB); 1681 1682 for (unsigned i = 0, e = Syms.size(); i != e; ++i) 1683 OutStreamer.EmitLabel(Syms[i]); 1684 } 1685 1686 // Print the main label for the block. 1687 if (MBB->pred_empty() || isBlockOnlyReachableByFallthrough(MBB)) { 1688 if (isVerbose() && OutStreamer.hasRawTextSupport()) { 1689 if (const BasicBlock *BB = MBB->getBasicBlock()) 1690 if (BB->hasName()) 1691 OutStreamer.AddComment("%" + BB->getName()); 1692 1693 EmitBasicBlockLoopComments(*MBB, LI, *this); 1694 1695 // NOTE: Want this comment at start of line, don't emit with AddComment. 1696 OutStreamer.EmitRawText(Twine(MAI->getCommentString()) + " BB#" + 1697 Twine(MBB->getNumber()) + ":"); 1698 } 1699 } else { 1700 if (isVerbose()) { 1701 if (const BasicBlock *BB = MBB->getBasicBlock()) 1702 if (BB->hasName()) 1703 OutStreamer.AddComment("%" + BB->getName()); 1704 EmitBasicBlockLoopComments(*MBB, LI, *this); 1705 } 1706 1707 OutStreamer.EmitLabel(MBB->getSymbol()); 1708 } 1709} 1710 1711void AsmPrinter::EmitVisibility(MCSymbol *Sym, unsigned Visibility) const { 1712 MCSymbolAttr Attr = MCSA_Invalid; 1713 1714 switch (Visibility) { 1715 default: break; 1716 case GlobalValue::HiddenVisibility: 1717 Attr = MAI->getHiddenVisibilityAttr(); 1718 break; 1719 case GlobalValue::ProtectedVisibility: 1720 Attr = MAI->getProtectedVisibilityAttr(); 1721 break; 1722 } 1723 1724 if (Attr != MCSA_Invalid) 1725 OutStreamer.EmitSymbolAttribute(Sym, Attr); 1726} 1727 1728/// isBlockOnlyReachableByFallthough - Return true if the basic block has 1729/// exactly one predecessor and the control transfer mechanism between 1730/// the predecessor and this block is a fall-through. 1731bool AsmPrinter:: 1732isBlockOnlyReachableByFallthrough(const MachineBasicBlock *MBB) const { 1733 // If this is a landing pad, it isn't a fall through. If it has no preds, 1734 // then nothing falls through to it. 1735 if (MBB->isLandingPad() || MBB->pred_empty()) 1736 return false; 1737 1738 // If there isn't exactly one predecessor, it can't be a fall through. 1739 MachineBasicBlock::const_pred_iterator PI = MBB->pred_begin(), PI2 = PI; 1740 ++PI2; 1741 if (PI2 != MBB->pred_end()) 1742 return false; 1743 1744 // The predecessor has to be immediately before this block. 1745 const MachineBasicBlock *Pred = *PI; 1746 1747 if (!Pred->isLayoutSuccessor(MBB)) 1748 return false; 1749 1750 // If the block is completely empty, then it definitely does fall through. 1751 if (Pred->empty()) 1752 return true; 1753 1754 // Otherwise, check the last instruction. 1755 const MachineInstr &LastInst = Pred->back(); 1756 return !LastInst.getDesc().isBarrier(); 1757} 1758 1759 1760 1761GCMetadataPrinter *AsmPrinter::GetOrCreateGCPrinter(GCStrategy *S) { 1762 if (!S->usesMetadata()) 1763 return 0; 1764 1765 gcp_map_type &GCMap = getGCMap(GCMetadataPrinters); 1766 gcp_map_type::iterator GCPI = GCMap.find(S); 1767 if (GCPI != GCMap.end()) 1768 return GCPI->second; 1769 1770 const char *Name = S->getName().c_str(); 1771 1772 for (GCMetadataPrinterRegistry::iterator 1773 I = GCMetadataPrinterRegistry::begin(), 1774 E = GCMetadataPrinterRegistry::end(); I != E; ++I) 1775 if (strcmp(Name, I->getName()) == 0) { 1776 GCMetadataPrinter *GMP = I->instantiate(); 1777 GMP->S = S; 1778 GCMap.insert(std::make_pair(S, GMP)); 1779 return GMP; 1780 } 1781 1782 report_fatal_error("no GCMetadataPrinter registered for GC: " + Twine(Name)); 1783 return 0; 1784} 1785 1786