AsmPrinter.cpp revision fbd947e63c59e0d8012b8358102e6f344b482c04
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" 45using namespace llvm; 46 47STATISTIC(EmittedInsts, "Number of machine instrs printed"); 48 49char AsmPrinter::ID = 0; 50 51typedef DenseMap<GCStrategy*,GCMetadataPrinter*> gcp_map_type; 52static gcp_map_type &getGCMap(void *&P) { 53 if (P == 0) 54 P = new gcp_map_type(); 55 return *(gcp_map_type*)P; 56} 57 58 59AsmPrinter::AsmPrinter(TargetMachine &tm, MCStreamer &Streamer) 60 : MachineFunctionPass(&ID), 61 TM(tm), MAI(tm.getMCAsmInfo()), 62 OutContext(Streamer.getContext()), 63 OutStreamer(Streamer), 64 LastMI(0), LastFn(0), Counter(~0U), SetCounter(0) { 65 DD = 0; DE = 0; MMI = 0; LI = 0; 66 GCMetadataPrinters = 0; 67 VerboseAsm = Streamer.isVerboseAsm(); 68} 69 70AsmPrinter::~AsmPrinter() { 71 assert(DD == 0 && DE == 0 && "Debug/EH info didn't get finalized"); 72 73 if (GCMetadataPrinters != 0) { 74 gcp_map_type &GCMap = getGCMap(GCMetadataPrinters); 75 76 for (gcp_map_type::iterator I = GCMap.begin(), E = GCMap.end(); I != E; ++I) 77 delete I->second; 78 delete &GCMap; 79 GCMetadataPrinters = 0; 80 } 81 82 delete &OutStreamer; 83} 84 85/// getFunctionNumber - Return a unique ID for the current function. 86/// 87unsigned AsmPrinter::getFunctionNumber() const { 88 return MF->getFunctionNumber(); 89} 90 91TargetLoweringObjectFile &AsmPrinter::getObjFileLowering() const { 92 return TM.getTargetLowering()->getObjFileLowering(); 93} 94 95 96/// getTargetData - Return information about data layout. 97const TargetData &AsmPrinter::getTargetData() const { 98 return *TM.getTargetData(); 99} 100 101/// getCurrentSection() - Return the current section we are emitting to. 102const MCSection *AsmPrinter::getCurrentSection() const { 103 return OutStreamer.getCurrentSection(); 104} 105 106 107 108void AsmPrinter::getAnalysisUsage(AnalysisUsage &AU) const { 109 AU.setPreservesAll(); 110 MachineFunctionPass::getAnalysisUsage(AU); 111 AU.addRequired<MachineModuleInfo>(); 112 AU.addRequired<GCModuleInfo>(); 113 if (isVerbose()) 114 AU.addRequired<MachineLoopInfo>(); 115} 116 117bool AsmPrinter::doInitialization(Module &M) { 118 MMI = getAnalysisIfAvailable<MachineModuleInfo>(); 119 MMI->AnalyzeModule(M); 120 121 // Initialize TargetLoweringObjectFile. 122 const_cast<TargetLoweringObjectFile&>(getObjFileLowering()) 123 .Initialize(OutContext, TM); 124 125 Mang = new Mangler(OutContext, *TM.getTargetData()); 126 127 // Allow the target to emit any magic that it wants at the start of the file. 128 EmitStartOfAsmFile(M); 129 130 // Very minimal debug info. It is ignored if we emit actual debug info. If we 131 // don't, this at least helps the user find where a global came from. 132 if (MAI->hasSingleParameterDotFile()) { 133 // .file "foo.c" 134 OutStreamer.EmitFileDirective(M.getModuleIdentifier()); 135 } 136 137 GCModuleInfo *MI = getAnalysisIfAvailable<GCModuleInfo>(); 138 assert(MI && "AsmPrinter didn't require GCModuleInfo?"); 139 for (GCModuleInfo::iterator I = MI->begin(), E = MI->end(); I != E; ++I) 140 if (GCMetadataPrinter *MP = GetOrCreateGCPrinter(*I)) 141 MP->beginAssembly(*this); 142 143 // Emit module-level inline asm if it exists. 144 if (!M.getModuleInlineAsm().empty()) { 145 OutStreamer.AddComment("Start of file scope inline assembly"); 146 OutStreamer.AddBlankLine(); 147 EmitInlineAsm(M.getModuleInlineAsm(), 0/*no loc cookie*/); 148 OutStreamer.AddComment("End of file scope inline assembly"); 149 OutStreamer.AddBlankLine(); 150 } 151 152 if (MAI->doesSupportDebugInformation()) 153 DD = new DwarfDebug(this, &M); 154 155 if (MAI->doesSupportExceptionHandling()) 156 DE = new DwarfException(this); 157 158 return false; 159} 160 161void AsmPrinter::EmitLinkage(unsigned Linkage, MCSymbol *GVSym) const { 162 switch ((GlobalValue::LinkageTypes)Linkage) { 163 case GlobalValue::CommonLinkage: 164 case GlobalValue::LinkOnceAnyLinkage: 165 case GlobalValue::LinkOnceODRLinkage: 166 case GlobalValue::WeakAnyLinkage: 167 case GlobalValue::WeakODRLinkage: 168 case GlobalValue::LinkerPrivateLinkage: 169 if (MAI->getWeakDefDirective() != 0) { 170 // .globl _foo 171 OutStreamer.EmitSymbolAttribute(GVSym, MCSA_Global); 172 // .weak_definition _foo 173 OutStreamer.EmitSymbolAttribute(GVSym, MCSA_WeakDefinition); 174 } else if (const char *LinkOnce = MAI->getLinkOnceDirective()) { 175 // .globl _foo 176 OutStreamer.EmitSymbolAttribute(GVSym, MCSA_Global); 177 // FIXME: linkonce should be a section attribute, handled by COFF Section 178 // assignment. 179 // http://sourceware.org/binutils/docs-2.20/as/Linkonce.html#Linkonce 180 // .linkonce discard 181 // FIXME: It would be nice to use .linkonce samesize for non-common 182 // globals. 183 OutStreamer.EmitRawText(StringRef(LinkOnce)); 184 } else { 185 // .weak _foo 186 OutStreamer.EmitSymbolAttribute(GVSym, MCSA_Weak); 187 } 188 break; 189 case GlobalValue::DLLExportLinkage: 190 case GlobalValue::AppendingLinkage: 191 // FIXME: appending linkage variables should go into a section of 192 // their name or something. For now, just emit them as external. 193 case GlobalValue::ExternalLinkage: 194 // If external or appending, declare as a global symbol. 195 // .globl _foo 196 OutStreamer.EmitSymbolAttribute(GVSym, MCSA_Global); 197 break; 198 case GlobalValue::PrivateLinkage: 199 case GlobalValue::InternalLinkage: 200 break; 201 default: 202 llvm_unreachable("Unknown linkage type!"); 203 } 204} 205 206 207/// EmitGlobalVariable - Emit the specified global variable to the .s file. 208void AsmPrinter::EmitGlobalVariable(const GlobalVariable *GV) { 209 if (!GV->hasInitializer()) // External globals require no code. 210 return; 211 212 // Check to see if this is a special global used by LLVM, if so, emit it. 213 if (EmitSpecialLLVMGlobal(GV)) 214 return; 215 216 MCSymbol *GVSym = Mang->getSymbol(GV); 217 EmitVisibility(GVSym, GV->getVisibility()); 218 219 if (MAI->hasDotTypeDotSizeDirective()) 220 OutStreamer.EmitSymbolAttribute(GVSym, MCSA_ELF_TypeObject); 221 222 SectionKind GVKind = TargetLoweringObjectFile::getKindForGlobal(GV, TM); 223 224 const TargetData *TD = TM.getTargetData(); 225 unsigned Size = TD->getTypeAllocSize(GV->getType()->getElementType()); 226 unsigned AlignLog = TD->getPreferredAlignmentLog(GV); 227 228 // Handle common and BSS local symbols (.lcomm). 229 if (GVKind.isCommon() || GVKind.isBSSLocal()) { 230 if (Size == 0) Size = 1; // .comm Foo, 0 is undefined, avoid it. 231 232 if (isVerbose()) { 233 WriteAsOperand(OutStreamer.GetCommentOS(), GV, 234 /*PrintType=*/false, GV->getParent()); 235 OutStreamer.GetCommentOS() << '\n'; 236 } 237 238 // Handle common symbols. 239 if (GVKind.isCommon()) { 240 // .comm _foo, 42, 4 241 OutStreamer.EmitCommonSymbol(GVSym, Size, 1 << AlignLog); 242 return; 243 } 244 245 // Handle local BSS symbols. 246 if (MAI->hasMachoZeroFillDirective()) { 247 const MCSection *TheSection = 248 getObjFileLowering().SectionForGlobal(GV, GVKind, Mang, TM); 249 // .zerofill __DATA, __bss, _foo, 400, 5 250 OutStreamer.EmitZerofill(TheSection, GVSym, Size, 1 << AlignLog); 251 return; 252 } 253 254 if (MAI->hasLCOMMDirective()) { 255 // .lcomm _foo, 42 256 OutStreamer.EmitLocalCommonSymbol(GVSym, Size); 257 return; 258 } 259 260 // .local _foo 261 OutStreamer.EmitSymbolAttribute(GVSym, MCSA_Local); 262 // .comm _foo, 42, 4 263 OutStreamer.EmitCommonSymbol(GVSym, Size, 1 << AlignLog); 264 return; 265 } 266 267 const MCSection *TheSection = 268 getObjFileLowering().SectionForGlobal(GV, GVKind, Mang, TM); 269 270 // Handle the zerofill directive on darwin, which is a special form of BSS 271 // emission. 272 if (GVKind.isBSSExtern() && MAI->hasMachoZeroFillDirective()) { 273 // .globl _foo 274 OutStreamer.EmitSymbolAttribute(GVSym, MCSA_Global); 275 // .zerofill __DATA, __common, _foo, 400, 5 276 OutStreamer.EmitZerofill(TheSection, GVSym, Size, 1 << AlignLog); 277 return; 278 } 279 280 OutStreamer.SwitchSection(TheSection); 281 282 EmitLinkage(GV->getLinkage(), GVSym); 283 EmitAlignment(AlignLog, GV); 284 285 if (isVerbose()) { 286 WriteAsOperand(OutStreamer.GetCommentOS(), GV, 287 /*PrintType=*/false, GV->getParent()); 288 OutStreamer.GetCommentOS() << '\n'; 289 } 290 OutStreamer.EmitLabel(GVSym); 291 292 EmitGlobalConstant(GV->getInitializer()); 293 294 if (MAI->hasDotTypeDotSizeDirective()) 295 // .size foo, 42 296 OutStreamer.EmitELFSize(GVSym, MCConstantExpr::Create(Size, OutContext)); 297 298 OutStreamer.AddBlankLine(); 299} 300 301/// EmitFunctionHeader - This method emits the header for the current 302/// function. 303void AsmPrinter::EmitFunctionHeader() { 304 // Print out constants referenced by the function 305 EmitConstantPool(); 306 307 // Print the 'header' of function. 308 const Function *F = MF->getFunction(); 309 310 OutStreamer.SwitchSection(getObjFileLowering().SectionForGlobal(F, Mang, TM)); 311 EmitVisibility(CurrentFnSym, F->getVisibility()); 312 313 EmitLinkage(F->getLinkage(), CurrentFnSym); 314 EmitAlignment(MF->getAlignment(), F); 315 316 if (MAI->hasDotTypeDotSizeDirective()) 317 OutStreamer.EmitSymbolAttribute(CurrentFnSym, MCSA_ELF_TypeFunction); 318 319 if (isVerbose()) { 320 WriteAsOperand(OutStreamer.GetCommentOS(), F, 321 /*PrintType=*/false, F->getParent()); 322 OutStreamer.GetCommentOS() << '\n'; 323 } 324 325 // Emit the CurrentFnSym. This is a virtual function to allow targets to 326 // do their wild and crazy things as required. 327 EmitFunctionEntryLabel(); 328 329 // If the function had address-taken blocks that got deleted, then we have 330 // references to the dangling symbols. Emit them at the start of the function 331 // so that we don't get references to undefined symbols. 332 std::vector<MCSymbol*> DeadBlockSyms; 333 MMI->takeDeletedSymbolsForFunction(F, DeadBlockSyms); 334 for (unsigned i = 0, e = DeadBlockSyms.size(); i != e; ++i) { 335 OutStreamer.AddComment("Address taken block that was later removed"); 336 OutStreamer.EmitLabel(DeadBlockSyms[i]); 337 } 338 339 // Add some workaround for linkonce linkage on Cygwin\MinGW. 340 if (MAI->getLinkOnceDirective() != 0 && 341 (F->hasLinkOnceLinkage() || F->hasWeakLinkage())) { 342 // FIXME: What is this? 343 MCSymbol *FakeStub = 344 OutContext.GetOrCreateSymbol(Twine("Lllvm$workaround$fake$stub$")+ 345 CurrentFnSym->getName()); 346 OutStreamer.EmitLabel(FakeStub); 347 } 348 349 // Emit pre-function debug and/or EH information. 350 if (DE) DE->BeginFunction(MF); 351 if (DD) DD->beginFunction(MF); 352} 353 354/// EmitFunctionEntryLabel - Emit the label that is the entrypoint for the 355/// function. This can be overridden by targets as required to do custom stuff. 356void AsmPrinter::EmitFunctionEntryLabel() { 357 OutStreamer.EmitLabel(CurrentFnSym); 358} 359 360 361/// EmitComments - Pretty-print comments for instructions. 362static void EmitComments(const MachineInstr &MI, raw_ostream &CommentOS) { 363 const MachineFunction *MF = MI.getParent()->getParent(); 364 const TargetMachine &TM = MF->getTarget(); 365 366 DebugLoc DL = MI.getDebugLoc(); 367 if (!DL.isUnknown()) { // Print source line info. 368 DIScope Scope(DL.getScope(MF->getFunction()->getContext())); 369 // Omit the directory, because it's likely to be long and uninteresting. 370 if (Scope.Verify()) 371 CommentOS << Scope.getFilename(); 372 else 373 CommentOS << "<unknown>"; 374 CommentOS << ':' << DL.getLine(); 375 if (DL.getCol() != 0) 376 CommentOS << ':' << DL.getCol(); 377 CommentOS << '\n'; 378 } 379 380 // Check for spills and reloads 381 int FI; 382 383 const MachineFrameInfo *FrameInfo = MF->getFrameInfo(); 384 385 // We assume a single instruction only has a spill or reload, not 386 // both. 387 const MachineMemOperand *MMO; 388 if (TM.getInstrInfo()->isLoadFromStackSlotPostFE(&MI, FI)) { 389 if (FrameInfo->isSpillSlotObjectIndex(FI)) { 390 MMO = *MI.memoperands_begin(); 391 CommentOS << MMO->getSize() << "-byte Reload\n"; 392 } 393 } else if (TM.getInstrInfo()->hasLoadFromStackSlot(&MI, MMO, FI)) { 394 if (FrameInfo->isSpillSlotObjectIndex(FI)) 395 CommentOS << MMO->getSize() << "-byte Folded Reload\n"; 396 } else if (TM.getInstrInfo()->isStoreToStackSlotPostFE(&MI, FI)) { 397 if (FrameInfo->isSpillSlotObjectIndex(FI)) { 398 MMO = *MI.memoperands_begin(); 399 CommentOS << MMO->getSize() << "-byte Spill\n"; 400 } 401 } else if (TM.getInstrInfo()->hasStoreToStackSlot(&MI, MMO, FI)) { 402 if (FrameInfo->isSpillSlotObjectIndex(FI)) 403 CommentOS << MMO->getSize() << "-byte Folded Spill\n"; 404 } 405 406 // Check for spill-induced copies 407 unsigned SrcReg, DstReg, SrcSubIdx, DstSubIdx; 408 if (TM.getInstrInfo()->isMoveInstr(MI, SrcReg, DstReg, 409 SrcSubIdx, DstSubIdx)) { 410 if (MI.getAsmPrinterFlag(MachineInstr::ReloadReuse)) 411 CommentOS << " Reload Reuse\n"; 412 } 413} 414 415/// EmitImplicitDef - This method emits the specified machine instruction 416/// that is an implicit def. 417static void EmitImplicitDef(const MachineInstr *MI, AsmPrinter &AP) { 418 unsigned RegNo = MI->getOperand(0).getReg(); 419 AP.OutStreamer.AddComment(Twine("implicit-def: ") + 420 AP.TM.getRegisterInfo()->getName(RegNo)); 421 AP.OutStreamer.AddBlankLine(); 422} 423 424static void EmitKill(const MachineInstr *MI, AsmPrinter &AP) { 425 std::string Str = "kill:"; 426 for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) { 427 const MachineOperand &Op = MI->getOperand(i); 428 assert(Op.isReg() && "KILL instruction must have only register operands"); 429 Str += ' '; 430 Str += AP.TM.getRegisterInfo()->getName(Op.getReg()); 431 Str += (Op.isDef() ? "<def>" : "<kill>"); 432 } 433 AP.OutStreamer.AddComment(Str); 434 AP.OutStreamer.AddBlankLine(); 435} 436 437/// EmitDebugValueComment - This method handles the target-independent form 438/// of DBG_VALUE, returning true if it was able to do so. A false return 439/// means the target will need to handle MI in EmitInstruction. 440static bool EmitDebugValueComment(const MachineInstr *MI, AsmPrinter &AP) { 441 char buf[100]; 442 std::string Str = "\t"; 443 Str += AP.MAI->getCommentString(); 444 Str += "DEBUG_VALUE: "; 445 // This code handles only the 3-operand target-independent form. 446 if (MI->getNumOperands() != 3) 447 return false; 448 449 // cast away const; DIetc do not take const operands for some reason. 450 DIVariable V((MDNode*)(MI->getOperand(2).getMetadata())); 451 Str += V.getName(); 452 Str += " <- "; 453 454 // Register or immediate value. Register 0 means undef. 455 if (MI->getOperand(0).isFPImm()) { 456 APFloat APF = APFloat(MI->getOperand(0).getFPImm()->getValueAPF()); 457 if (MI->getOperand(0).getFPImm()->getType()->isFloatTy()) { 458 sprintf(buf, "%e", APF.convertToFloat()); 459 Str += buf; 460 } else if (MI->getOperand(0).getFPImm()->getType()->isDoubleTy()) { 461 sprintf(buf, "%e", APF.convertToDouble()); 462 Str += buf; 463 } else { 464 // There is no good way to print long double. Convert a copy to 465 // double. Ah well, it's only a comment. 466 bool ignored; 467 APF.convert(APFloat::IEEEdouble, APFloat::rmNearestTiesToEven, 468 &ignored); 469 Str += "(long double) "; 470 sprintf(buf, "%e", APF.convertToDouble()); 471 Str += buf; 472 } 473 } else if (MI->getOperand(0).isImm()) { 474 sprintf(buf, "%lld", MI->getOperand(0).getImm()); 475 Str += buf; 476 } else if (MI->getOperand(0).isReg()) { 477 if (MI->getOperand(0).getReg() == 0) { 478 // Suppress offset, it is not meaningful here. 479 Str += "undef"; 480 // NOTE: Want this comment at start of line, don't emit with AddComment. 481 AP.OutStreamer.EmitRawText(Twine(Str)); 482 return true; 483 } 484 Str += AP.TM.getRegisterInfo()->getName(MI->getOperand(0).getReg()); 485 } else 486 llvm_unreachable("Unknown operand type"); 487 488 Str += '+'; 489 sprintf(buf, "%lld", MI->getOperand(1).getImm()); 490 Str += buf; 491 // NOTE: Want this comment at start of line, don't emit with AddComment. 492 AP.OutStreamer.EmitRawText(Twine(Str)); 493 return true; 494} 495 496/// EmitFunctionBody - This method emits the body and trailer for a 497/// function. 498void AsmPrinter::EmitFunctionBody() { 499 // Emit target-specific gunk before the function body. 500 EmitFunctionBodyStart(); 501 502 bool ShouldPrintDebugScopes = DD && MMI->hasDebugInfo(); 503 504 // Print out code for the function. 505 bool HasAnyRealCode = false; 506 for (MachineFunction::const_iterator I = MF->begin(), E = MF->end(); 507 I != E; ++I) { 508 // Print a label for the basic block. 509 EmitBasicBlockStart(I); 510 for (MachineBasicBlock::const_iterator II = I->begin(), IE = I->end(); 511 II != IE; ++II) { 512 // Print the assembly for the instruction. 513 if (!II->isLabel()) 514 HasAnyRealCode = true; 515 516 ++EmittedInsts; 517 518 if (ShouldPrintDebugScopes) 519 DD->beginScope(II); 520 521 if (isVerbose()) 522 EmitComments(*II, OutStreamer.GetCommentOS()); 523 524 switch (II->getOpcode()) { 525 case TargetOpcode::DBG_LABEL: 526 case TargetOpcode::EH_LABEL: 527 case TargetOpcode::GC_LABEL: 528 OutStreamer.EmitLabel(II->getOperand(0).getMCSymbol()); 529 break; 530 case TargetOpcode::INLINEASM: 531 EmitInlineAsm(II); 532 break; 533 case TargetOpcode::DBG_VALUE: 534 if (isVerbose()) { 535 if (!EmitDebugValueComment(II, *this)) 536 EmitInstruction(II); 537 } 538 break; 539 case TargetOpcode::IMPLICIT_DEF: 540 if (isVerbose()) EmitImplicitDef(II, *this); 541 break; 542 case TargetOpcode::KILL: 543 if (isVerbose()) EmitKill(II, *this); 544 break; 545 default: 546 EmitInstruction(II); 547 break; 548 } 549 550 if (ShouldPrintDebugScopes) 551 DD->endScope(II); 552 } 553 } 554 555 // If the function is empty and the object file uses .subsections_via_symbols, 556 // then we need to emit *something* to the function body to prevent the 557 // labels from collapsing together. Just emit a 0 byte. 558 if (MAI->hasSubsectionsViaSymbols() && !HasAnyRealCode) 559 OutStreamer.EmitIntValue(0, 1, 0/*addrspace*/); 560 561 // Emit target-specific gunk after the function body. 562 EmitFunctionBodyEnd(); 563 564 // If the target wants a .size directive for the size of the function, emit 565 // it. 566 if (MAI->hasDotTypeDotSizeDirective()) { 567 // Create a symbol for the end of function, so we can get the size as 568 // difference between the function label and the temp label. 569 MCSymbol *FnEndLabel = OutContext.CreateTempSymbol(); 570 OutStreamer.EmitLabel(FnEndLabel); 571 572 const MCExpr *SizeExp = 573 MCBinaryExpr::CreateSub(MCSymbolRefExpr::Create(FnEndLabel, OutContext), 574 MCSymbolRefExpr::Create(CurrentFnSym, OutContext), 575 OutContext); 576 OutStreamer.EmitELFSize(CurrentFnSym, SizeExp); 577 } 578 579 // Emit post-function debug information. 580 if (DD) DD->endFunction(MF); 581 if (DE) DE->EndFunction(); 582 MMI->EndFunction(); 583 584 // Print out jump tables referenced by the function. 585 EmitJumpTableInfo(); 586 587 OutStreamer.AddBlankLine(); 588} 589 590 591bool AsmPrinter::doFinalization(Module &M) { 592 // Emit global variables. 593 for (Module::const_global_iterator I = M.global_begin(), E = M.global_end(); 594 I != E; ++I) 595 EmitGlobalVariable(I); 596 597 // Finalize debug and EH information. 598 if (DE) { 599 DE->EndModule(); 600 delete DE; DE = 0; 601 } 602 if (DD) { 603 DD->endModule(); 604 delete DD; DD = 0; 605 } 606 607 // If the target wants to know about weak references, print them all. 608 if (MAI->getWeakRefDirective()) { 609 // FIXME: This is not lazy, it would be nice to only print weak references 610 // to stuff that is actually used. Note that doing so would require targets 611 // to notice uses in operands (due to constant exprs etc). This should 612 // happen with the MC stuff eventually. 613 614 // Print out module-level global variables here. 615 for (Module::const_global_iterator I = M.global_begin(), E = M.global_end(); 616 I != E; ++I) { 617 if (!I->hasExternalWeakLinkage()) continue; 618 OutStreamer.EmitSymbolAttribute(Mang->getSymbol(I), MCSA_WeakReference); 619 } 620 621 for (Module::const_iterator I = M.begin(), E = M.end(); I != E; ++I) { 622 if (!I->hasExternalWeakLinkage()) continue; 623 OutStreamer.EmitSymbolAttribute(Mang->getSymbol(I), MCSA_WeakReference); 624 } 625 } 626 627 if (MAI->hasSetDirective()) { 628 OutStreamer.AddBlankLine(); 629 for (Module::const_alias_iterator I = M.alias_begin(), E = M.alias_end(); 630 I != E; ++I) { 631 MCSymbol *Name = Mang->getSymbol(I); 632 633 const GlobalValue *GV = cast<GlobalValue>(I->getAliasedGlobal()); 634 MCSymbol *Target = Mang->getSymbol(GV); 635 636 if (I->hasExternalLinkage() || !MAI->getWeakRefDirective()) 637 OutStreamer.EmitSymbolAttribute(Name, MCSA_Global); 638 else if (I->hasWeakLinkage()) 639 OutStreamer.EmitSymbolAttribute(Name, MCSA_WeakReference); 640 else 641 assert(I->hasLocalLinkage() && "Invalid alias linkage"); 642 643 EmitVisibility(Name, I->getVisibility()); 644 645 // Emit the directives as assignments aka .set: 646 OutStreamer.EmitAssignment(Name, 647 MCSymbolRefExpr::Create(Target, OutContext)); 648 } 649 } 650 651 GCModuleInfo *MI = getAnalysisIfAvailable<GCModuleInfo>(); 652 assert(MI && "AsmPrinter didn't require GCModuleInfo?"); 653 for (GCModuleInfo::iterator I = MI->end(), E = MI->begin(); I != E; ) 654 if (GCMetadataPrinter *MP = GetOrCreateGCPrinter(*--I)) 655 MP->finishAssembly(*this); 656 657 // If we don't have any trampolines, then we don't require stack memory 658 // to be executable. Some targets have a directive to declare this. 659 Function *InitTrampolineIntrinsic = M.getFunction("llvm.init.trampoline"); 660 if (!InitTrampolineIntrinsic || InitTrampolineIntrinsic->use_empty()) 661 if (MCSection *S = MAI->getNonexecutableStackSection(OutContext)) 662 OutStreamer.SwitchSection(S); 663 664 // Allow the target to emit any magic that it wants at the end of the file, 665 // after everything else has gone out. 666 EmitEndOfAsmFile(M); 667 668 delete Mang; Mang = 0; 669 MMI = 0; 670 671 OutStreamer.Finish(); 672 return false; 673} 674 675void AsmPrinter::SetupMachineFunction(MachineFunction &MF) { 676 this->MF = &MF; 677 // Get the function symbol. 678 CurrentFnSym = Mang->getSymbol(MF.getFunction()); 679 680 if (isVerbose()) 681 LI = &getAnalysis<MachineLoopInfo>(); 682} 683 684namespace { 685 // SectionCPs - Keep track the alignment, constpool entries per Section. 686 struct SectionCPs { 687 const MCSection *S; 688 unsigned Alignment; 689 SmallVector<unsigned, 4> CPEs; 690 SectionCPs(const MCSection *s, unsigned a) : S(s), Alignment(a) {} 691 }; 692} 693 694/// EmitConstantPool - Print to the current output stream assembly 695/// representations of the constants in the constant pool MCP. This is 696/// used to print out constants which have been "spilled to memory" by 697/// the code generator. 698/// 699void AsmPrinter::EmitConstantPool() { 700 const MachineConstantPool *MCP = MF->getConstantPool(); 701 const std::vector<MachineConstantPoolEntry> &CP = MCP->getConstants(); 702 if (CP.empty()) return; 703 704 // Calculate sections for constant pool entries. We collect entries to go into 705 // the same section together to reduce amount of section switch statements. 706 SmallVector<SectionCPs, 4> CPSections; 707 for (unsigned i = 0, e = CP.size(); i != e; ++i) { 708 const MachineConstantPoolEntry &CPE = CP[i]; 709 unsigned Align = CPE.getAlignment(); 710 711 SectionKind Kind; 712 switch (CPE.getRelocationInfo()) { 713 default: llvm_unreachable("Unknown section kind"); 714 case 2: Kind = SectionKind::getReadOnlyWithRel(); break; 715 case 1: 716 Kind = SectionKind::getReadOnlyWithRelLocal(); 717 break; 718 case 0: 719 switch (TM.getTargetData()->getTypeAllocSize(CPE.getType())) { 720 case 4: Kind = SectionKind::getMergeableConst4(); break; 721 case 8: Kind = SectionKind::getMergeableConst8(); break; 722 case 16: Kind = SectionKind::getMergeableConst16();break; 723 default: Kind = SectionKind::getMergeableConst(); break; 724 } 725 } 726 727 const MCSection *S = getObjFileLowering().getSectionForConstant(Kind); 728 729 // The number of sections are small, just do a linear search from the 730 // last section to the first. 731 bool Found = false; 732 unsigned SecIdx = CPSections.size(); 733 while (SecIdx != 0) { 734 if (CPSections[--SecIdx].S == S) { 735 Found = true; 736 break; 737 } 738 } 739 if (!Found) { 740 SecIdx = CPSections.size(); 741 CPSections.push_back(SectionCPs(S, Align)); 742 } 743 744 if (Align > CPSections[SecIdx].Alignment) 745 CPSections[SecIdx].Alignment = Align; 746 CPSections[SecIdx].CPEs.push_back(i); 747 } 748 749 // Now print stuff into the calculated sections. 750 for (unsigned i = 0, e = CPSections.size(); i != e; ++i) { 751 OutStreamer.SwitchSection(CPSections[i].S); 752 EmitAlignment(Log2_32(CPSections[i].Alignment)); 753 754 unsigned Offset = 0; 755 for (unsigned j = 0, ee = CPSections[i].CPEs.size(); j != ee; ++j) { 756 unsigned CPI = CPSections[i].CPEs[j]; 757 MachineConstantPoolEntry CPE = CP[CPI]; 758 759 // Emit inter-object padding for alignment. 760 unsigned AlignMask = CPE.getAlignment() - 1; 761 unsigned NewOffset = (Offset + AlignMask) & ~AlignMask; 762 OutStreamer.EmitFill(NewOffset - Offset, 0/*fillval*/, 0/*addrspace*/); 763 764 const Type *Ty = CPE.getType(); 765 Offset = NewOffset + TM.getTargetData()->getTypeAllocSize(Ty); 766 767 // Emit the label with a comment on it. 768 if (isVerbose()) { 769 OutStreamer.GetCommentOS() << "constant pool "; 770 WriteTypeSymbolic(OutStreamer.GetCommentOS(), CPE.getType(), 771 MF->getFunction()->getParent()); 772 OutStreamer.GetCommentOS() << '\n'; 773 } 774 OutStreamer.EmitLabel(GetCPISymbol(CPI)); 775 776 if (CPE.isMachineConstantPoolEntry()) 777 EmitMachineConstantPoolValue(CPE.Val.MachineCPVal); 778 else 779 EmitGlobalConstant(CPE.Val.ConstVal); 780 } 781 } 782} 783 784/// EmitJumpTableInfo - Print assembly representations of the jump tables used 785/// by the current function to the current output stream. 786/// 787void AsmPrinter::EmitJumpTableInfo() { 788 const MachineJumpTableInfo *MJTI = MF->getJumpTableInfo(); 789 if (MJTI == 0) return; 790 if (MJTI->getEntryKind() == MachineJumpTableInfo::EK_Inline) return; 791 const std::vector<MachineJumpTableEntry> &JT = MJTI->getJumpTables(); 792 if (JT.empty()) return; 793 794 // Pick the directive to use to print the jump table entries, and switch to 795 // the appropriate section. 796 const Function *F = MF->getFunction(); 797 bool JTInDiffSection = false; 798 if (// In PIC mode, we need to emit the jump table to the same section as the 799 // function body itself, otherwise the label differences won't make sense. 800 // FIXME: Need a better predicate for this: what about custom entries? 801 MJTI->getEntryKind() == MachineJumpTableInfo::EK_LabelDifference32 || 802 // We should also do if the section name is NULL or function is declared 803 // in discardable section 804 // FIXME: this isn't the right predicate, should be based on the MCSection 805 // for the function. 806 F->isWeakForLinker()) { 807 OutStreamer.SwitchSection(getObjFileLowering().SectionForGlobal(F,Mang,TM)); 808 } else { 809 // Otherwise, drop it in the readonly section. 810 const MCSection *ReadOnlySection = 811 getObjFileLowering().getSectionForConstant(SectionKind::getReadOnly()); 812 OutStreamer.SwitchSection(ReadOnlySection); 813 JTInDiffSection = true; 814 } 815 816 EmitAlignment(Log2_32(MJTI->getEntryAlignment(*TM.getTargetData()))); 817 818 for (unsigned JTI = 0, e = JT.size(); JTI != e; ++JTI) { 819 const std::vector<MachineBasicBlock*> &JTBBs = JT[JTI].MBBs; 820 821 // If this jump table was deleted, ignore it. 822 if (JTBBs.empty()) continue; 823 824 // For the EK_LabelDifference32 entry, if the target supports .set, emit a 825 // .set directive for each unique entry. This reduces the number of 826 // relocations the assembler will generate for the jump table. 827 if (MJTI->getEntryKind() == MachineJumpTableInfo::EK_LabelDifference32 && 828 MAI->hasSetDirective()) { 829 SmallPtrSet<const MachineBasicBlock*, 16> EmittedSets; 830 const TargetLowering *TLI = TM.getTargetLowering(); 831 const MCExpr *Base = TLI->getPICJumpTableRelocBaseExpr(MF,JTI,OutContext); 832 for (unsigned ii = 0, ee = JTBBs.size(); ii != ee; ++ii) { 833 const MachineBasicBlock *MBB = JTBBs[ii]; 834 if (!EmittedSets.insert(MBB)) continue; 835 836 // .set LJTSet, LBB32-base 837 const MCExpr *LHS = 838 MCSymbolRefExpr::Create(MBB->getSymbol(), OutContext); 839 OutStreamer.EmitAssignment(GetJTSetSymbol(JTI, MBB->getNumber()), 840 MCBinaryExpr::CreateSub(LHS, Base, OutContext)); 841 } 842 } 843 844 // On some targets (e.g. Darwin) we want to emit two consequtive labels 845 // before each jump table. The first label is never referenced, but tells 846 // the assembler and linker the extents of the jump table object. The 847 // second label is actually referenced by the code. 848 if (JTInDiffSection && MAI->getLinkerPrivateGlobalPrefix()[0]) 849 // FIXME: This doesn't have to have any specific name, just any randomly 850 // named and numbered 'l' label would work. Simplify GetJTISymbol. 851 OutStreamer.EmitLabel(GetJTISymbol(JTI, true)); 852 853 OutStreamer.EmitLabel(GetJTISymbol(JTI)); 854 855 for (unsigned ii = 0, ee = JTBBs.size(); ii != ee; ++ii) 856 EmitJumpTableEntry(MJTI, JTBBs[ii], JTI); 857 } 858} 859 860/// EmitJumpTableEntry - Emit a jump table entry for the specified MBB to the 861/// current stream. 862void AsmPrinter::EmitJumpTableEntry(const MachineJumpTableInfo *MJTI, 863 const MachineBasicBlock *MBB, 864 unsigned UID) const { 865 const MCExpr *Value = 0; 866 switch (MJTI->getEntryKind()) { 867 case MachineJumpTableInfo::EK_Inline: 868 llvm_unreachable("Cannot emit EK_Inline jump table entry"); break; 869 case MachineJumpTableInfo::EK_Custom32: 870 Value = TM.getTargetLowering()->LowerCustomJumpTableEntry(MJTI, MBB, UID, 871 OutContext); 872 break; 873 case MachineJumpTableInfo::EK_BlockAddress: 874 // EK_BlockAddress - Each entry is a plain address of block, e.g.: 875 // .word LBB123 876 Value = MCSymbolRefExpr::Create(MBB->getSymbol(), OutContext); 877 break; 878 case MachineJumpTableInfo::EK_GPRel32BlockAddress: { 879 // EK_GPRel32BlockAddress - Each entry is an address of block, encoded 880 // with a relocation as gp-relative, e.g.: 881 // .gprel32 LBB123 882 MCSymbol *MBBSym = MBB->getSymbol(); 883 OutStreamer.EmitGPRel32Value(MCSymbolRefExpr::Create(MBBSym, OutContext)); 884 return; 885 } 886 887 case MachineJumpTableInfo::EK_LabelDifference32: { 888 // EK_LabelDifference32 - Each entry is the address of the block minus 889 // the address of the jump table. This is used for PIC jump tables where 890 // gprel32 is not supported. e.g.: 891 // .word LBB123 - LJTI1_2 892 // If the .set directive is supported, this is emitted as: 893 // .set L4_5_set_123, LBB123 - LJTI1_2 894 // .word L4_5_set_123 895 896 // If we have emitted set directives for the jump table entries, print 897 // them rather than the entries themselves. If we're emitting PIC, then 898 // emit the table entries as differences between two text section labels. 899 if (MAI->hasSetDirective()) { 900 // If we used .set, reference the .set's symbol. 901 Value = MCSymbolRefExpr::Create(GetJTSetSymbol(UID, MBB->getNumber()), 902 OutContext); 903 break; 904 } 905 // Otherwise, use the difference as the jump table entry. 906 Value = MCSymbolRefExpr::Create(MBB->getSymbol(), OutContext); 907 const MCExpr *JTI = MCSymbolRefExpr::Create(GetJTISymbol(UID), OutContext); 908 Value = MCBinaryExpr::CreateSub(Value, JTI, OutContext); 909 break; 910 } 911 } 912 913 assert(Value && "Unknown entry kind!"); 914 915 unsigned EntrySize = MJTI->getEntrySize(*TM.getTargetData()); 916 OutStreamer.EmitValue(Value, EntrySize, /*addrspace*/0); 917} 918 919 920/// EmitSpecialLLVMGlobal - Check to see if the specified global is a 921/// special global used by LLVM. If so, emit it and return true, otherwise 922/// do nothing and return false. 923bool AsmPrinter::EmitSpecialLLVMGlobal(const GlobalVariable *GV) { 924 if (GV->getName() == "llvm.used") { 925 if (MAI->hasNoDeadStrip()) // No need to emit this at all. 926 EmitLLVMUsedList(GV->getInitializer()); 927 return true; 928 } 929 930 // Ignore debug and non-emitted data. This handles llvm.compiler.used. 931 if (GV->getSection() == "llvm.metadata" || 932 GV->hasAvailableExternallyLinkage()) 933 return true; 934 935 if (!GV->hasAppendingLinkage()) return false; 936 937 assert(GV->hasInitializer() && "Not a special LLVM global!"); 938 939 const TargetData *TD = TM.getTargetData(); 940 unsigned Align = Log2_32(TD->getPointerPrefAlignment()); 941 if (GV->getName() == "llvm.global_ctors") { 942 OutStreamer.SwitchSection(getObjFileLowering().getStaticCtorSection()); 943 EmitAlignment(Align, 0); 944 EmitXXStructorList(GV->getInitializer()); 945 946 if (TM.getRelocationModel() == Reloc::Static && 947 MAI->hasStaticCtorDtorReferenceInStaticMode()) { 948 StringRef Sym(".constructors_used"); 949 OutStreamer.EmitSymbolAttribute(OutContext.GetOrCreateSymbol(Sym), 950 MCSA_Reference); 951 } 952 return true; 953 } 954 955 if (GV->getName() == "llvm.global_dtors") { 956 OutStreamer.SwitchSection(getObjFileLowering().getStaticDtorSection()); 957 EmitAlignment(Align, 0); 958 EmitXXStructorList(GV->getInitializer()); 959 960 if (TM.getRelocationModel() == Reloc::Static && 961 MAI->hasStaticCtorDtorReferenceInStaticMode()) { 962 StringRef Sym(".destructors_used"); 963 OutStreamer.EmitSymbolAttribute(OutContext.GetOrCreateSymbol(Sym), 964 MCSA_Reference); 965 } 966 return true; 967 } 968 969 return false; 970} 971 972/// EmitLLVMUsedList - For targets that define a MAI::UsedDirective, mark each 973/// global in the specified llvm.used list for which emitUsedDirectiveFor 974/// is true, as being used with this directive. 975void AsmPrinter::EmitLLVMUsedList(Constant *List) { 976 // Should be an array of 'i8*'. 977 ConstantArray *InitList = dyn_cast<ConstantArray>(List); 978 if (InitList == 0) return; 979 980 for (unsigned i = 0, e = InitList->getNumOperands(); i != e; ++i) { 981 const GlobalValue *GV = 982 dyn_cast<GlobalValue>(InitList->getOperand(i)->stripPointerCasts()); 983 if (GV && getObjFileLowering().shouldEmitUsedDirectiveFor(GV, Mang)) 984 OutStreamer.EmitSymbolAttribute(Mang->getSymbol(GV), MCSA_NoDeadStrip); 985 } 986} 987 988/// EmitXXStructorList - Emit the ctor or dtor list. This just prints out the 989/// function pointers, ignoring the init priority. 990void AsmPrinter::EmitXXStructorList(Constant *List) { 991 // Should be an array of '{ int, void ()* }' structs. The first value is the 992 // init priority, which we ignore. 993 if (!isa<ConstantArray>(List)) return; 994 ConstantArray *InitList = cast<ConstantArray>(List); 995 for (unsigned i = 0, e = InitList->getNumOperands(); i != e; ++i) 996 if (ConstantStruct *CS = dyn_cast<ConstantStruct>(InitList->getOperand(i))){ 997 if (CS->getNumOperands() != 2) return; // Not array of 2-element structs. 998 999 if (CS->getOperand(1)->isNullValue()) 1000 return; // Found a null terminator, exit printing. 1001 // Emit the function pointer. 1002 EmitGlobalConstant(CS->getOperand(1)); 1003 } 1004} 1005 1006//===--------------------------------------------------------------------===// 1007// Emission and print routines 1008// 1009 1010/// EmitInt8 - Emit a byte directive and value. 1011/// 1012void AsmPrinter::EmitInt8(int Value) const { 1013 OutStreamer.EmitIntValue(Value, 1, 0/*addrspace*/); 1014} 1015 1016/// EmitInt16 - Emit a short directive and value. 1017/// 1018void AsmPrinter::EmitInt16(int Value) const { 1019 OutStreamer.EmitIntValue(Value, 2, 0/*addrspace*/); 1020} 1021 1022/// EmitInt32 - Emit a long directive and value. 1023/// 1024void AsmPrinter::EmitInt32(int Value) const { 1025 OutStreamer.EmitIntValue(Value, 4, 0/*addrspace*/); 1026} 1027 1028/// EmitLabelDifference - Emit something like ".long Hi-Lo" where the size 1029/// in bytes of the directive is specified by Size and Hi/Lo specify the 1030/// labels. This implicitly uses .set if it is available. 1031void AsmPrinter::EmitLabelDifference(const MCSymbol *Hi, const MCSymbol *Lo, 1032 unsigned Size) const { 1033 // Get the Hi-Lo expression. 1034 const MCExpr *Diff = 1035 MCBinaryExpr::CreateSub(MCSymbolRefExpr::Create(Hi, OutContext), 1036 MCSymbolRefExpr::Create(Lo, OutContext), 1037 OutContext); 1038 1039 if (!MAI->hasSetDirective()) { 1040 OutStreamer.EmitValue(Diff, Size, 0/*AddrSpace*/); 1041 return; 1042 } 1043 1044 // Otherwise, emit with .set (aka assignment). 1045 MCSymbol *SetLabel = GetTempSymbol("set", SetCounter++); 1046 OutStreamer.EmitAssignment(SetLabel, Diff); 1047 OutStreamer.EmitSymbolValue(SetLabel, Size, 0/*AddrSpace*/); 1048} 1049 1050 1051//===----------------------------------------------------------------------===// 1052 1053// EmitAlignment - Emit an alignment directive to the specified power of 1054// two boundary. For example, if you pass in 3 here, you will get an 8 1055// byte alignment. If a global value is specified, and if that global has 1056// an explicit alignment requested, it will unconditionally override the 1057// alignment request. However, if ForcedAlignBits is specified, this value 1058// has final say: the ultimate alignment will be the max of ForcedAlignBits 1059// and the alignment computed with NumBits and the global. 1060// 1061// The algorithm is: 1062// Align = NumBits; 1063// if (GV && GV->hasalignment) Align = GV->getalignment(); 1064// Align = std::max(Align, ForcedAlignBits); 1065// 1066void AsmPrinter::EmitAlignment(unsigned NumBits, const GlobalValue *GV, 1067 unsigned ForcedAlignBits, 1068 bool UseFillExpr) const { 1069 if (GV && GV->getAlignment()) 1070 NumBits = Log2_32(GV->getAlignment()); 1071 NumBits = std::max(NumBits, ForcedAlignBits); 1072 1073 if (NumBits == 0) return; // No need to emit alignment. 1074 1075 if (getCurrentSection()->getKind().isText()) 1076 OutStreamer.EmitCodeAlignment(1 << NumBits); 1077 else 1078 OutStreamer.EmitValueToAlignment(1 << NumBits, 0, 1, 0); 1079} 1080 1081/// LowerConstant - Lower the specified LLVM Constant to an MCExpr. 1082/// 1083static const MCExpr *LowerConstant(const Constant *CV, AsmPrinter &AP) { 1084 MCContext &Ctx = AP.OutContext; 1085 1086 if (CV->isNullValue() || isa<UndefValue>(CV)) 1087 return MCConstantExpr::Create(0, Ctx); 1088 1089 if (const ConstantInt *CI = dyn_cast<ConstantInt>(CV)) 1090 return MCConstantExpr::Create(CI->getZExtValue(), Ctx); 1091 1092 if (const GlobalValue *GV = dyn_cast<GlobalValue>(CV)) 1093 return MCSymbolRefExpr::Create(AP.Mang->getSymbol(GV), Ctx); 1094 if (const BlockAddress *BA = dyn_cast<BlockAddress>(CV)) 1095 return MCSymbolRefExpr::Create(AP.GetBlockAddressSymbol(BA), Ctx); 1096 1097 const ConstantExpr *CE = dyn_cast<ConstantExpr>(CV); 1098 if (CE == 0) { 1099 llvm_unreachable("Unknown constant value to lower!"); 1100 return MCConstantExpr::Create(0, Ctx); 1101 } 1102 1103 switch (CE->getOpcode()) { 1104 default: 1105 // If the code isn't optimized, there may be outstanding folding 1106 // opportunities. Attempt to fold the expression using TargetData as a 1107 // last resort before giving up. 1108 if (Constant *C = 1109 ConstantFoldConstantExpression(CE, AP.TM.getTargetData())) 1110 if (C != CE) 1111 return LowerConstant(C, AP); 1112#ifndef NDEBUG 1113 CE->dump(); 1114#endif 1115 llvm_unreachable("FIXME: Don't support this constant expr"); 1116 case Instruction::GetElementPtr: { 1117 const TargetData &TD = *AP.TM.getTargetData(); 1118 // Generate a symbolic expression for the byte address 1119 const Constant *PtrVal = CE->getOperand(0); 1120 SmallVector<Value*, 8> IdxVec(CE->op_begin()+1, CE->op_end()); 1121 int64_t Offset = TD.getIndexedOffset(PtrVal->getType(), &IdxVec[0], 1122 IdxVec.size()); 1123 1124 const MCExpr *Base = LowerConstant(CE->getOperand(0), AP); 1125 if (Offset == 0) 1126 return Base; 1127 1128 // Truncate/sext the offset to the pointer size. 1129 if (TD.getPointerSizeInBits() != 64) { 1130 int SExtAmount = 64-TD.getPointerSizeInBits(); 1131 Offset = (Offset << SExtAmount) >> SExtAmount; 1132 } 1133 1134 return MCBinaryExpr::CreateAdd(Base, MCConstantExpr::Create(Offset, Ctx), 1135 Ctx); 1136 } 1137 1138 case Instruction::Trunc: 1139 // We emit the value and depend on the assembler to truncate the generated 1140 // expression properly. This is important for differences between 1141 // blockaddress labels. Since the two labels are in the same function, it 1142 // is reasonable to treat their delta as a 32-bit value. 1143 // FALL THROUGH. 1144 case Instruction::BitCast: 1145 return LowerConstant(CE->getOperand(0), AP); 1146 1147 case Instruction::IntToPtr: { 1148 const TargetData &TD = *AP.TM.getTargetData(); 1149 // Handle casts to pointers by changing them into casts to the appropriate 1150 // integer type. This promotes constant folding and simplifies this code. 1151 Constant *Op = CE->getOperand(0); 1152 Op = ConstantExpr::getIntegerCast(Op, TD.getIntPtrType(CV->getContext()), 1153 false/*ZExt*/); 1154 return LowerConstant(Op, AP); 1155 } 1156 1157 case Instruction::PtrToInt: { 1158 const TargetData &TD = *AP.TM.getTargetData(); 1159 // Support only foldable casts to/from pointers that can be eliminated by 1160 // changing the pointer to the appropriately sized integer type. 1161 Constant *Op = CE->getOperand(0); 1162 const Type *Ty = CE->getType(); 1163 1164 const MCExpr *OpExpr = LowerConstant(Op, AP); 1165 1166 // We can emit the pointer value into this slot if the slot is an 1167 // integer slot equal to the size of the pointer. 1168 if (TD.getTypeAllocSize(Ty) == TD.getTypeAllocSize(Op->getType())) 1169 return OpExpr; 1170 1171 // Otherwise the pointer is smaller than the resultant integer, mask off 1172 // the high bits so we are sure to get a proper truncation if the input is 1173 // a constant expr. 1174 unsigned InBits = TD.getTypeAllocSizeInBits(Op->getType()); 1175 const MCExpr *MaskExpr = MCConstantExpr::Create(~0ULL >> (64-InBits), Ctx); 1176 return MCBinaryExpr::CreateAnd(OpExpr, MaskExpr, Ctx); 1177 } 1178 1179 // The MC library also has a right-shift operator, but it isn't consistently 1180 // signed or unsigned between different targets. 1181 case Instruction::Add: 1182 case Instruction::Sub: 1183 case Instruction::Mul: 1184 case Instruction::SDiv: 1185 case Instruction::SRem: 1186 case Instruction::Shl: 1187 case Instruction::And: 1188 case Instruction::Or: 1189 case Instruction::Xor: { 1190 const MCExpr *LHS = LowerConstant(CE->getOperand(0), AP); 1191 const MCExpr *RHS = LowerConstant(CE->getOperand(1), AP); 1192 switch (CE->getOpcode()) { 1193 default: llvm_unreachable("Unknown binary operator constant cast expr"); 1194 case Instruction::Add: return MCBinaryExpr::CreateAdd(LHS, RHS, Ctx); 1195 case Instruction::Sub: return MCBinaryExpr::CreateSub(LHS, RHS, Ctx); 1196 case Instruction::Mul: return MCBinaryExpr::CreateMul(LHS, RHS, Ctx); 1197 case Instruction::SDiv: return MCBinaryExpr::CreateDiv(LHS, RHS, Ctx); 1198 case Instruction::SRem: return MCBinaryExpr::CreateMod(LHS, RHS, Ctx); 1199 case Instruction::Shl: return MCBinaryExpr::CreateShl(LHS, RHS, Ctx); 1200 case Instruction::And: return MCBinaryExpr::CreateAnd(LHS, RHS, Ctx); 1201 case Instruction::Or: return MCBinaryExpr::CreateOr (LHS, RHS, Ctx); 1202 case Instruction::Xor: return MCBinaryExpr::CreateXor(LHS, RHS, Ctx); 1203 } 1204 } 1205 } 1206} 1207 1208static void EmitGlobalConstantArray(const ConstantArray *CA, unsigned AddrSpace, 1209 AsmPrinter &AP) { 1210 if (AddrSpace != 0 || !CA->isString()) { 1211 // Not a string. Print the values in successive locations 1212 for (unsigned i = 0, e = CA->getNumOperands(); i != e; ++i) 1213 AP.EmitGlobalConstant(CA->getOperand(i), AddrSpace); 1214 return; 1215 } 1216 1217 // Otherwise, it can be emitted as .ascii. 1218 SmallVector<char, 128> TmpVec; 1219 TmpVec.reserve(CA->getNumOperands()); 1220 for (unsigned i = 0, e = CA->getNumOperands(); i != e; ++i) 1221 TmpVec.push_back(cast<ConstantInt>(CA->getOperand(i))->getZExtValue()); 1222 1223 AP.OutStreamer.EmitBytes(StringRef(TmpVec.data(), TmpVec.size()), AddrSpace); 1224} 1225 1226static void EmitGlobalConstantVector(const ConstantVector *CV, 1227 unsigned AddrSpace, AsmPrinter &AP) { 1228 for (unsigned i = 0, e = CV->getType()->getNumElements(); i != e; ++i) 1229 AP.EmitGlobalConstant(CV->getOperand(i), AddrSpace); 1230} 1231 1232static void EmitGlobalConstantStruct(const ConstantStruct *CS, 1233 unsigned AddrSpace, AsmPrinter &AP) { 1234 // Print the fields in successive locations. Pad to align if needed! 1235 const TargetData *TD = AP.TM.getTargetData(); 1236 unsigned Size = TD->getTypeAllocSize(CS->getType()); 1237 const StructLayout *Layout = TD->getStructLayout(CS->getType()); 1238 uint64_t SizeSoFar = 0; 1239 for (unsigned i = 0, e = CS->getNumOperands(); i != e; ++i) { 1240 const Constant *Field = CS->getOperand(i); 1241 1242 // Check if padding is needed and insert one or more 0s. 1243 uint64_t FieldSize = TD->getTypeAllocSize(Field->getType()); 1244 uint64_t PadSize = ((i == e-1 ? Size : Layout->getElementOffset(i+1)) 1245 - Layout->getElementOffset(i)) - FieldSize; 1246 SizeSoFar += FieldSize + PadSize; 1247 1248 // Now print the actual field value. 1249 AP.EmitGlobalConstant(Field, AddrSpace); 1250 1251 // Insert padding - this may include padding to increase the size of the 1252 // current field up to the ABI size (if the struct is not packed) as well 1253 // as padding to ensure that the next field starts at the right offset. 1254 AP.OutStreamer.EmitZeros(PadSize, AddrSpace); 1255 } 1256 assert(SizeSoFar == Layout->getSizeInBytes() && 1257 "Layout of constant struct may be incorrect!"); 1258} 1259 1260static void EmitGlobalConstantUnion(const ConstantUnion *CU, 1261 unsigned AddrSpace, AsmPrinter &AP) { 1262 const TargetData *TD = AP.TM.getTargetData(); 1263 unsigned Size = TD->getTypeAllocSize(CU->getType()); 1264 1265 const Constant *Contents = CU->getOperand(0); 1266 unsigned FilledSize = TD->getTypeAllocSize(Contents->getType()); 1267 1268 // Print the actually filled part 1269 AP.EmitGlobalConstant(Contents, AddrSpace); 1270 1271 // And pad with enough zeroes 1272 AP.OutStreamer.EmitZeros(Size-FilledSize, AddrSpace); 1273} 1274 1275static void EmitGlobalConstantFP(const ConstantFP *CFP, unsigned AddrSpace, 1276 AsmPrinter &AP) { 1277 // FP Constants are printed as integer constants to avoid losing 1278 // precision. 1279 if (CFP->getType()->isDoubleTy()) { 1280 if (AP.isVerbose()) { 1281 double Val = CFP->getValueAPF().convertToDouble(); 1282 AP.OutStreamer.GetCommentOS() << "double " << Val << '\n'; 1283 } 1284 1285 uint64_t Val = CFP->getValueAPF().bitcastToAPInt().getZExtValue(); 1286 AP.OutStreamer.EmitIntValue(Val, 8, AddrSpace); 1287 return; 1288 } 1289 1290 if (CFP->getType()->isFloatTy()) { 1291 if (AP.isVerbose()) { 1292 float Val = CFP->getValueAPF().convertToFloat(); 1293 AP.OutStreamer.GetCommentOS() << "float " << Val << '\n'; 1294 } 1295 uint64_t Val = CFP->getValueAPF().bitcastToAPInt().getZExtValue(); 1296 AP.OutStreamer.EmitIntValue(Val, 4, AddrSpace); 1297 return; 1298 } 1299 1300 if (CFP->getType()->isX86_FP80Ty()) { 1301 // all long double variants are printed as hex 1302 // API needed to prevent premature destruction 1303 APInt API = CFP->getValueAPF().bitcastToAPInt(); 1304 const uint64_t *p = API.getRawData(); 1305 if (AP.isVerbose()) { 1306 // Convert to double so we can print the approximate val as a comment. 1307 APFloat DoubleVal = CFP->getValueAPF(); 1308 bool ignored; 1309 DoubleVal.convert(APFloat::IEEEdouble, APFloat::rmNearestTiesToEven, 1310 &ignored); 1311 AP.OutStreamer.GetCommentOS() << "x86_fp80 ~= " 1312 << DoubleVal.convertToDouble() << '\n'; 1313 } 1314 1315 if (AP.TM.getTargetData()->isBigEndian()) { 1316 AP.OutStreamer.EmitIntValue(p[1], 2, AddrSpace); 1317 AP.OutStreamer.EmitIntValue(p[0], 8, AddrSpace); 1318 } else { 1319 AP.OutStreamer.EmitIntValue(p[0], 8, AddrSpace); 1320 AP.OutStreamer.EmitIntValue(p[1], 2, AddrSpace); 1321 } 1322 1323 // Emit the tail padding for the long double. 1324 const TargetData &TD = *AP.TM.getTargetData(); 1325 AP.OutStreamer.EmitZeros(TD.getTypeAllocSize(CFP->getType()) - 1326 TD.getTypeStoreSize(CFP->getType()), AddrSpace); 1327 return; 1328 } 1329 1330 assert(CFP->getType()->isPPC_FP128Ty() && 1331 "Floating point constant type not handled"); 1332 // All long double variants are printed as hex 1333 // API needed to prevent premature destruction. 1334 APInt API = CFP->getValueAPF().bitcastToAPInt(); 1335 const uint64_t *p = API.getRawData(); 1336 if (AP.TM.getTargetData()->isBigEndian()) { 1337 AP.OutStreamer.EmitIntValue(p[0], 8, AddrSpace); 1338 AP.OutStreamer.EmitIntValue(p[1], 8, AddrSpace); 1339 } else { 1340 AP.OutStreamer.EmitIntValue(p[1], 8, AddrSpace); 1341 AP.OutStreamer.EmitIntValue(p[0], 8, AddrSpace); 1342 } 1343} 1344 1345static void EmitGlobalConstantLargeInt(const ConstantInt *CI, 1346 unsigned AddrSpace, AsmPrinter &AP) { 1347 const TargetData *TD = AP.TM.getTargetData(); 1348 unsigned BitWidth = CI->getBitWidth(); 1349 assert((BitWidth & 63) == 0 && "only support multiples of 64-bits"); 1350 1351 // We don't expect assemblers to support integer data directives 1352 // for more than 64 bits, so we emit the data in at most 64-bit 1353 // quantities at a time. 1354 const uint64_t *RawData = CI->getValue().getRawData(); 1355 for (unsigned i = 0, e = BitWidth / 64; i != e; ++i) { 1356 uint64_t Val = TD->isBigEndian() ? RawData[e - i - 1] : RawData[i]; 1357 AP.OutStreamer.EmitIntValue(Val, 8, AddrSpace); 1358 } 1359} 1360 1361/// EmitGlobalConstant - Print a general LLVM constant to the .s file. 1362void AsmPrinter::EmitGlobalConstant(const Constant *CV, unsigned AddrSpace) { 1363 if (isa<ConstantAggregateZero>(CV) || isa<UndefValue>(CV)) { 1364 uint64_t Size = TM.getTargetData()->getTypeAllocSize(CV->getType()); 1365 if (Size == 0) Size = 1; // An empty "_foo:" followed by a section is undef. 1366 return OutStreamer.EmitZeros(Size, AddrSpace); 1367 } 1368 1369 if (const ConstantInt *CI = dyn_cast<ConstantInt>(CV)) { 1370 unsigned Size = TM.getTargetData()->getTypeAllocSize(CV->getType()); 1371 switch (Size) { 1372 case 1: 1373 case 2: 1374 case 4: 1375 case 8: 1376 if (isVerbose()) 1377 OutStreamer.GetCommentOS() << format("0x%llx\n", CI->getZExtValue()); 1378 OutStreamer.EmitIntValue(CI->getZExtValue(), Size, AddrSpace); 1379 return; 1380 default: 1381 EmitGlobalConstantLargeInt(CI, AddrSpace, *this); 1382 return; 1383 } 1384 } 1385 1386 if (const ConstantArray *CVA = dyn_cast<ConstantArray>(CV)) 1387 return EmitGlobalConstantArray(CVA, AddrSpace, *this); 1388 1389 if (const ConstantStruct *CVS = dyn_cast<ConstantStruct>(CV)) 1390 return EmitGlobalConstantStruct(CVS, AddrSpace, *this); 1391 1392 if (const ConstantFP *CFP = dyn_cast<ConstantFP>(CV)) 1393 return EmitGlobalConstantFP(CFP, AddrSpace, *this); 1394 1395 if (isa<ConstantPointerNull>(CV)) { 1396 unsigned Size = TM.getTargetData()->getTypeAllocSize(CV->getType()); 1397 OutStreamer.EmitIntValue(0, Size, AddrSpace); 1398 return; 1399 } 1400 1401 if (const ConstantUnion *CVU = dyn_cast<ConstantUnion>(CV)) 1402 return EmitGlobalConstantUnion(CVU, AddrSpace, *this); 1403 1404 if (const ConstantVector *V = dyn_cast<ConstantVector>(CV)) 1405 return EmitGlobalConstantVector(V, AddrSpace, *this); 1406 1407 // Otherwise, it must be a ConstantExpr. Lower it to an MCExpr, then emit it 1408 // thread the streamer with EmitValue. 1409 OutStreamer.EmitValue(LowerConstant(CV, *this), 1410 TM.getTargetData()->getTypeAllocSize(CV->getType()), 1411 AddrSpace); 1412} 1413 1414void AsmPrinter::EmitMachineConstantPoolValue(MachineConstantPoolValue *MCPV) { 1415 // Target doesn't support this yet! 1416 llvm_unreachable("Target does not support EmitMachineConstantPoolValue"); 1417} 1418 1419void AsmPrinter::printOffset(int64_t Offset, raw_ostream &OS) const { 1420 if (Offset > 0) 1421 OS << '+' << Offset; 1422 else if (Offset < 0) 1423 OS << Offset; 1424} 1425 1426//===----------------------------------------------------------------------===// 1427// Symbol Lowering Routines. 1428//===----------------------------------------------------------------------===// 1429 1430/// GetTempSymbol - Return the MCSymbol corresponding to the assembler 1431/// temporary label with the specified stem and unique ID. 1432MCSymbol *AsmPrinter::GetTempSymbol(StringRef Name, unsigned ID) const { 1433 return OutContext.GetOrCreateSymbol(Twine(MAI->getPrivateGlobalPrefix()) + 1434 Name + Twine(ID)); 1435} 1436 1437/// GetTempSymbol - Return an assembler temporary label with the specified 1438/// stem. 1439MCSymbol *AsmPrinter::GetTempSymbol(StringRef Name) const { 1440 return OutContext.GetOrCreateSymbol(Twine(MAI->getPrivateGlobalPrefix())+ 1441 Name); 1442} 1443 1444 1445MCSymbol *AsmPrinter::GetBlockAddressSymbol(const BlockAddress *BA) const { 1446 return MMI->getAddrLabelSymbol(BA->getBasicBlock()); 1447} 1448 1449MCSymbol *AsmPrinter::GetBlockAddressSymbol(const BasicBlock *BB) const { 1450 return MMI->getAddrLabelSymbol(BB); 1451} 1452 1453/// GetCPISymbol - Return the symbol for the specified constant pool entry. 1454MCSymbol *AsmPrinter::GetCPISymbol(unsigned CPID) const { 1455 return OutContext.GetOrCreateSymbol 1456 (Twine(MAI->getPrivateGlobalPrefix()) + "CPI" + Twine(getFunctionNumber()) 1457 + "_" + Twine(CPID)); 1458} 1459 1460/// GetJTISymbol - Return the symbol for the specified jump table entry. 1461MCSymbol *AsmPrinter::GetJTISymbol(unsigned JTID, bool isLinkerPrivate) const { 1462 return MF->getJTISymbol(JTID, OutContext, isLinkerPrivate); 1463} 1464 1465/// GetJTSetSymbol - Return the symbol for the specified jump table .set 1466/// FIXME: privatize to AsmPrinter. 1467MCSymbol *AsmPrinter::GetJTSetSymbol(unsigned UID, unsigned MBBID) const { 1468 return OutContext.GetOrCreateSymbol 1469 (Twine(MAI->getPrivateGlobalPrefix()) + Twine(getFunctionNumber()) + "_" + 1470 Twine(UID) + "_set_" + Twine(MBBID)); 1471} 1472 1473/// GetSymbolWithGlobalValueBase - Return the MCSymbol for a symbol with 1474/// global value name as its base, with the specified suffix, and where the 1475/// symbol is forced to have private linkage if ForcePrivate is true. 1476MCSymbol *AsmPrinter::GetSymbolWithGlobalValueBase(const GlobalValue *GV, 1477 StringRef Suffix, 1478 bool ForcePrivate) const { 1479 SmallString<60> NameStr; 1480 Mang->getNameWithPrefix(NameStr, GV, ForcePrivate); 1481 NameStr.append(Suffix.begin(), Suffix.end()); 1482 return OutContext.GetOrCreateSymbol(NameStr.str()); 1483} 1484 1485/// GetExternalSymbolSymbol - Return the MCSymbol for the specified 1486/// ExternalSymbol. 1487MCSymbol *AsmPrinter::GetExternalSymbolSymbol(StringRef Sym) const { 1488 SmallString<60> NameStr; 1489 Mang->getNameWithPrefix(NameStr, Sym); 1490 return OutContext.GetOrCreateSymbol(NameStr.str()); 1491} 1492 1493 1494 1495/// PrintParentLoopComment - Print comments about parent loops of this one. 1496static void PrintParentLoopComment(raw_ostream &OS, const MachineLoop *Loop, 1497 unsigned FunctionNumber) { 1498 if (Loop == 0) return; 1499 PrintParentLoopComment(OS, Loop->getParentLoop(), FunctionNumber); 1500 OS.indent(Loop->getLoopDepth()*2) 1501 << "Parent Loop BB" << FunctionNumber << "_" 1502 << Loop->getHeader()->getNumber() 1503 << " Depth=" << Loop->getLoopDepth() << '\n'; 1504} 1505 1506 1507/// PrintChildLoopComment - Print comments about child loops within 1508/// the loop for this basic block, with nesting. 1509static void PrintChildLoopComment(raw_ostream &OS, const MachineLoop *Loop, 1510 unsigned FunctionNumber) { 1511 // Add child loop information 1512 for (MachineLoop::iterator CL = Loop->begin(), E = Loop->end();CL != E; ++CL){ 1513 OS.indent((*CL)->getLoopDepth()*2) 1514 << "Child Loop BB" << FunctionNumber << "_" 1515 << (*CL)->getHeader()->getNumber() << " Depth " << (*CL)->getLoopDepth() 1516 << '\n'; 1517 PrintChildLoopComment(OS, *CL, FunctionNumber); 1518 } 1519} 1520 1521/// EmitBasicBlockLoopComments - Pretty-print comments for basic blocks. 1522static void EmitBasicBlockLoopComments(const MachineBasicBlock &MBB, 1523 const MachineLoopInfo *LI, 1524 const AsmPrinter &AP) { 1525 // Add loop depth information 1526 const MachineLoop *Loop = LI->getLoopFor(&MBB); 1527 if (Loop == 0) return; 1528 1529 MachineBasicBlock *Header = Loop->getHeader(); 1530 assert(Header && "No header for loop"); 1531 1532 // If this block is not a loop header, just print out what is the loop header 1533 // and return. 1534 if (Header != &MBB) { 1535 AP.OutStreamer.AddComment(" in Loop: Header=BB" + 1536 Twine(AP.getFunctionNumber())+"_" + 1537 Twine(Loop->getHeader()->getNumber())+ 1538 " Depth="+Twine(Loop->getLoopDepth())); 1539 return; 1540 } 1541 1542 // Otherwise, it is a loop header. Print out information about child and 1543 // parent loops. 1544 raw_ostream &OS = AP.OutStreamer.GetCommentOS(); 1545 1546 PrintParentLoopComment(OS, Loop->getParentLoop(), AP.getFunctionNumber()); 1547 1548 OS << "=>"; 1549 OS.indent(Loop->getLoopDepth()*2-2); 1550 1551 OS << "This "; 1552 if (Loop->empty()) 1553 OS << "Inner "; 1554 OS << "Loop Header: Depth=" + Twine(Loop->getLoopDepth()) << '\n'; 1555 1556 PrintChildLoopComment(OS, Loop, AP.getFunctionNumber()); 1557} 1558 1559 1560/// EmitBasicBlockStart - This method prints the label for the specified 1561/// MachineBasicBlock, an alignment (if present) and a comment describing 1562/// it if appropriate. 1563void AsmPrinter::EmitBasicBlockStart(const MachineBasicBlock *MBB) const { 1564 // Emit an alignment directive for this block, if needed. 1565 if (unsigned Align = MBB->getAlignment()) 1566 EmitAlignment(Log2_32(Align)); 1567 1568 // If the block has its address taken, emit any labels that were used to 1569 // reference the block. It is possible that there is more than one label 1570 // here, because multiple LLVM BB's may have been RAUW'd to this block after 1571 // the references were generated. 1572 if (MBB->hasAddressTaken()) { 1573 const BasicBlock *BB = MBB->getBasicBlock(); 1574 if (isVerbose()) 1575 OutStreamer.AddComment("Block address taken"); 1576 1577 std::vector<MCSymbol*> Syms = MMI->getAddrLabelSymbolToEmit(BB); 1578 1579 for (unsigned i = 0, e = Syms.size(); i != e; ++i) 1580 OutStreamer.EmitLabel(Syms[i]); 1581 } 1582 1583 // Print the main label for the block. 1584 if (MBB->pred_empty() || isBlockOnlyReachableByFallthrough(MBB)) { 1585 if (isVerbose() && OutStreamer.hasRawTextSupport()) { 1586 if (const BasicBlock *BB = MBB->getBasicBlock()) 1587 if (BB->hasName()) 1588 OutStreamer.AddComment("%" + BB->getName()); 1589 1590 EmitBasicBlockLoopComments(*MBB, LI, *this); 1591 1592 // NOTE: Want this comment at start of line, don't emit with AddComment. 1593 OutStreamer.EmitRawText(Twine(MAI->getCommentString()) + " BB#" + 1594 Twine(MBB->getNumber()) + ":"); 1595 } 1596 } else { 1597 if (isVerbose()) { 1598 if (const BasicBlock *BB = MBB->getBasicBlock()) 1599 if (BB->hasName()) 1600 OutStreamer.AddComment("%" + BB->getName()); 1601 EmitBasicBlockLoopComments(*MBB, LI, *this); 1602 } 1603 1604 OutStreamer.EmitLabel(MBB->getSymbol()); 1605 } 1606} 1607 1608void AsmPrinter::EmitVisibility(MCSymbol *Sym, unsigned Visibility) const { 1609 MCSymbolAttr Attr = MCSA_Invalid; 1610 1611 switch (Visibility) { 1612 default: break; 1613 case GlobalValue::HiddenVisibility: 1614 Attr = MAI->getHiddenVisibilityAttr(); 1615 break; 1616 case GlobalValue::ProtectedVisibility: 1617 Attr = MAI->getProtectedVisibilityAttr(); 1618 break; 1619 } 1620 1621 if (Attr != MCSA_Invalid) 1622 OutStreamer.EmitSymbolAttribute(Sym, Attr); 1623} 1624 1625/// isBlockOnlyReachableByFallthough - Return true if the basic block has 1626/// exactly one predecessor and the control transfer mechanism between 1627/// the predecessor and this block is a fall-through. 1628bool AsmPrinter:: 1629isBlockOnlyReachableByFallthrough(const MachineBasicBlock *MBB) const { 1630 // If this is a landing pad, it isn't a fall through. If it has no preds, 1631 // then nothing falls through to it. 1632 if (MBB->isLandingPad() || MBB->pred_empty()) 1633 return false; 1634 1635 // If there isn't exactly one predecessor, it can't be a fall through. 1636 MachineBasicBlock::const_pred_iterator PI = MBB->pred_begin(), PI2 = PI; 1637 ++PI2; 1638 if (PI2 != MBB->pred_end()) 1639 return false; 1640 1641 // The predecessor has to be immediately before this block. 1642 const MachineBasicBlock *Pred = *PI; 1643 1644 if (!Pred->isLayoutSuccessor(MBB)) 1645 return false; 1646 1647 // If the block is completely empty, then it definitely does fall through. 1648 if (Pred->empty()) 1649 return true; 1650 1651 // Otherwise, check the last instruction. 1652 const MachineInstr &LastInst = Pred->back(); 1653 return !LastInst.getDesc().isBarrier(); 1654} 1655 1656 1657 1658GCMetadataPrinter *AsmPrinter::GetOrCreateGCPrinter(GCStrategy *S) { 1659 if (!S->usesMetadata()) 1660 return 0; 1661 1662 gcp_map_type &GCMap = getGCMap(GCMetadataPrinters); 1663 gcp_map_type::iterator GCPI = GCMap.find(S); 1664 if (GCPI != GCMap.end()) 1665 return GCPI->second; 1666 1667 const char *Name = S->getName().c_str(); 1668 1669 for (GCMetadataPrinterRegistry::iterator 1670 I = GCMetadataPrinterRegistry::begin(), 1671 E = GCMetadataPrinterRegistry::end(); I != E; ++I) 1672 if (strcmp(Name, I->getName()) == 0) { 1673 GCMetadataPrinter *GMP = I->instantiate(); 1674 GMP->S = S; 1675 GCMap.insert(std::make_pair(S, GMP)); 1676 return GMP; 1677 } 1678 1679 llvm_report_error("no GCMetadataPrinter registered for GC: " + Twine(Name)); 1680 return 0; 1681} 1682 1683