1 //===-- X86AsmPrinter.cpp - Convert X86 LLVM code to AT&T assembly --------===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 // 9 // This file contains a printer that converts from our internal representation 10 // of machine-dependent LLVM code to X86 machine code. 11 // 12 //===----------------------------------------------------------------------===// 13 14 #include "X86AsmPrinter.h" 15 #include "MCTargetDesc/X86ATTInstPrinter.h" 16 #include "MCTargetDesc/X86BaseInfo.h" 17 #include "MCTargetDesc/X86TargetStreamer.h" 18 #include "TargetInfo/X86TargetInfo.h" 19 #include "X86InstrInfo.h" 20 #include "X86MachineFunctionInfo.h" 21 #include "llvm/BinaryFormat/COFF.h" 22 #include "llvm/BinaryFormat/ELF.h" 23 #include "llvm/CodeGen/MachineConstantPool.h" 24 #include "llvm/CodeGen/MachineModuleInfoImpls.h" 25 #include "llvm/CodeGen/TargetLoweringObjectFileImpl.h" 26 #include "llvm/IR/DerivedTypes.h" 27 #include "llvm/IR/InlineAsm.h" 28 #include "llvm/IR/Mangler.h" 29 #include "llvm/IR/Module.h" 30 #include "llvm/IR/Type.h" 31 #include "llvm/MC/MCCodeEmitter.h" 32 #include "llvm/MC/MCContext.h" 33 #include "llvm/MC/MCExpr.h" 34 #include "llvm/MC/MCSectionCOFF.h" 35 #include "llvm/MC/MCSectionELF.h" 36 #include "llvm/MC/MCSectionMachO.h" 37 #include "llvm/MC/MCStreamer.h" 38 #include "llvm/MC/MCSymbol.h" 39 #include "llvm/Support/Debug.h" 40 #include "llvm/Support/ErrorHandling.h" 41 #include "llvm/Support/MachineValueType.h" 42 #include "llvm/Support/TargetRegistry.h" 43 using namespace llvm; 44 45 X86AsmPrinter::X86AsmPrinter(TargetMachine &TM, 46 std::unique_ptr<MCStreamer> Streamer) 47 : AsmPrinter(TM, std::move(Streamer)), SM(*this), FM(*this) {} 48 49 //===----------------------------------------------------------------------===// 50 // Primitive Helper Functions. 51 //===----------------------------------------------------------------------===// 52 53 /// runOnMachineFunction - Emit the function body. 54 /// 55 bool X86AsmPrinter::runOnMachineFunction(MachineFunction &MF) { 56 Subtarget = &MF.getSubtarget<X86Subtarget>(); 57 58 SMShadowTracker.startFunction(MF); 59 CodeEmitter.reset(TM.getTarget().createMCCodeEmitter( 60 *Subtarget->getInstrInfo(), *Subtarget->getRegisterInfo(), 61 MF.getContext())); 62 63 EmitFPOData = 64 Subtarget->isTargetWin32() && MF.getMMI().getModule()->getCodeViewFlag(); 65 66 SetupMachineFunction(MF); 67 68 if (Subtarget->isTargetCOFF()) { 69 bool Local = MF.getFunction().hasLocalLinkage(); 70 OutStreamer->BeginCOFFSymbolDef(CurrentFnSym); 71 OutStreamer->EmitCOFFSymbolStorageClass( 72 Local ? COFF::IMAGE_SYM_CLASS_STATIC : COFF::IMAGE_SYM_CLASS_EXTERNAL); 73 OutStreamer->EmitCOFFSymbolType(COFF::IMAGE_SYM_DTYPE_FUNCTION 74 << COFF::SCT_COMPLEX_TYPE_SHIFT); 75 OutStreamer->EndCOFFSymbolDef(); 76 } 77 78 // Emit the rest of the function body. 79 EmitFunctionBody(); 80 81 // Emit the XRay table for this function. 82 emitXRayTable(); 83 84 EmitFPOData = false; 85 86 // We didn't modify anything. 87 return false; 88 } 89 90 void X86AsmPrinter::EmitFunctionBodyStart() { 91 if (EmitFPOData) { 92 if (auto *XTS = 93 static_cast<X86TargetStreamer *>(OutStreamer->getTargetStreamer())) 94 XTS->emitFPOProc( 95 CurrentFnSym, 96 MF->getInfo<X86MachineFunctionInfo>()->getArgumentStackSize()); 97 } 98 } 99 100 void X86AsmPrinter::EmitFunctionBodyEnd() { 101 if (EmitFPOData) { 102 if (auto *XTS = 103 static_cast<X86TargetStreamer *>(OutStreamer->getTargetStreamer())) 104 XTS->emitFPOEndProc(); 105 } 106 } 107 108 /// PrintSymbolOperand - Print a raw symbol reference operand. This handles 109 /// jump tables, constant pools, global address and external symbols, all of 110 /// which print to a label with various suffixes for relocation types etc. 111 void X86AsmPrinter::PrintSymbolOperand(const MachineOperand &MO, 112 raw_ostream &O) { 113 switch (MO.getType()) { 114 default: llvm_unreachable("unknown symbol type!"); 115 case MachineOperand::MO_ConstantPoolIndex: 116 GetCPISymbol(MO.getIndex())->print(O, MAI); 117 printOffset(MO.getOffset(), O); 118 break; 119 case MachineOperand::MO_GlobalAddress: { 120 const GlobalValue *GV = MO.getGlobal(); 121 122 MCSymbol *GVSym; 123 if (MO.getTargetFlags() == X86II::MO_DARWIN_NONLAZY || 124 MO.getTargetFlags() == X86II::MO_DARWIN_NONLAZY_PIC_BASE) 125 GVSym = getSymbolWithGlobalValueBase(GV, "$non_lazy_ptr"); 126 else 127 GVSym = getSymbol(GV); 128 129 // Handle dllimport linkage. 130 if (MO.getTargetFlags() == X86II::MO_DLLIMPORT) 131 GVSym = OutContext.getOrCreateSymbol(Twine("__imp_") + GVSym->getName()); 132 else if (MO.getTargetFlags() == X86II::MO_COFFSTUB) 133 GVSym = 134 OutContext.getOrCreateSymbol(Twine(".refptr.") + GVSym->getName()); 135 136 if (MO.getTargetFlags() == X86II::MO_DARWIN_NONLAZY || 137 MO.getTargetFlags() == X86II::MO_DARWIN_NONLAZY_PIC_BASE) { 138 MCSymbol *Sym = getSymbolWithGlobalValueBase(GV, "$non_lazy_ptr"); 139 MachineModuleInfoImpl::StubValueTy &StubSym = 140 MMI->getObjFileInfo<MachineModuleInfoMachO>().getGVStubEntry(Sym); 141 if (!StubSym.getPointer()) 142 StubSym = MachineModuleInfoImpl::StubValueTy(getSymbol(GV), 143 !GV->hasInternalLinkage()); 144 } 145 146 // If the name begins with a dollar-sign, enclose it in parens. We do this 147 // to avoid having it look like an integer immediate to the assembler. 148 if (GVSym->getName()[0] != '$') 149 GVSym->print(O, MAI); 150 else { 151 O << '('; 152 GVSym->print(O, MAI); 153 O << ')'; 154 } 155 printOffset(MO.getOffset(), O); 156 break; 157 } 158 } 159 160 switch (MO.getTargetFlags()) { 161 default: 162 llvm_unreachable("Unknown target flag on GV operand"); 163 case X86II::MO_NO_FLAG: // No flag. 164 break; 165 case X86II::MO_DARWIN_NONLAZY: 166 case X86II::MO_DLLIMPORT: 167 case X86II::MO_COFFSTUB: 168 // These affect the name of the symbol, not any suffix. 169 break; 170 case X86II::MO_GOT_ABSOLUTE_ADDRESS: 171 O << " + [.-"; 172 MF->getPICBaseSymbol()->print(O, MAI); 173 O << ']'; 174 break; 175 case X86II::MO_PIC_BASE_OFFSET: 176 case X86II::MO_DARWIN_NONLAZY_PIC_BASE: 177 O << '-'; 178 MF->getPICBaseSymbol()->print(O, MAI); 179 break; 180 case X86II::MO_TLSGD: O << "@TLSGD"; break; 181 case X86II::MO_TLSLD: O << "@TLSLD"; break; 182 case X86II::MO_TLSLDM: O << "@TLSLDM"; break; 183 case X86II::MO_GOTTPOFF: O << "@GOTTPOFF"; break; 184 case X86II::MO_INDNTPOFF: O << "@INDNTPOFF"; break; 185 case X86II::MO_TPOFF: O << "@TPOFF"; break; 186 case X86II::MO_DTPOFF: O << "@DTPOFF"; break; 187 case X86II::MO_NTPOFF: O << "@NTPOFF"; break; 188 case X86II::MO_GOTNTPOFF: O << "@GOTNTPOFF"; break; 189 case X86II::MO_GOTPCREL: O << "@GOTPCREL"; break; 190 case X86II::MO_GOT: O << "@GOT"; break; 191 case X86II::MO_GOTOFF: O << "@GOTOFF"; break; 192 case X86II::MO_PLT: O << "@PLT"; break; 193 case X86II::MO_TLVP: O << "@TLVP"; break; 194 case X86II::MO_TLVP_PIC_BASE: 195 O << "@TLVP" << '-'; 196 MF->getPICBaseSymbol()->print(O, MAI); 197 break; 198 case X86II::MO_SECREL: O << "@SECREL32"; break; 199 } 200 } 201 202 void X86AsmPrinter::PrintOperand(const MachineInstr *MI, unsigned OpNo, 203 raw_ostream &O) { 204 const MachineOperand &MO = MI->getOperand(OpNo); 205 const bool IsATT = MI->getInlineAsmDialect() == InlineAsm::AD_ATT; 206 switch (MO.getType()) { 207 default: llvm_unreachable("unknown operand type!"); 208 case MachineOperand::MO_Register: { 209 if (IsATT) 210 O << '%'; 211 O << X86ATTInstPrinter::getRegisterName(MO.getReg()); 212 return; 213 } 214 215 case MachineOperand::MO_Immediate: 216 if (IsATT) 217 O << '$'; 218 O << MO.getImm(); 219 return; 220 221 case MachineOperand::MO_GlobalAddress: { 222 if (IsATT) 223 O << '$'; 224 PrintSymbolOperand(MO, O); 225 break; 226 } 227 case MachineOperand::MO_BlockAddress: { 228 MCSymbol *Sym = GetBlockAddressSymbol(MO.getBlockAddress()); 229 Sym->print(O, MAI); 230 break; 231 } 232 } 233 } 234 235 /// PrintModifiedOperand - Print subregisters based on supplied modifier, 236 /// deferring to PrintOperand() if no modifier was supplied or if operand is not 237 /// a register. 238 void X86AsmPrinter::PrintModifiedOperand(const MachineInstr *MI, unsigned OpNo, 239 raw_ostream &O, const char *Modifier) { 240 const MachineOperand &MO = MI->getOperand(OpNo); 241 if (!Modifier || MO.getType() != MachineOperand::MO_Register) 242 return PrintOperand(MI, OpNo, O); 243 if (MI->getInlineAsmDialect() == InlineAsm::AD_ATT) 244 O << '%'; 245 unsigned Reg = MO.getReg(); 246 if (strncmp(Modifier, "subreg", strlen("subreg")) == 0) { 247 unsigned Size = (strcmp(Modifier+6,"64") == 0) ? 64 : 248 (strcmp(Modifier+6,"32") == 0) ? 32 : 249 (strcmp(Modifier+6,"16") == 0) ? 16 : 8; 250 Reg = getX86SubSuperRegister(Reg, Size); 251 } 252 O << X86ATTInstPrinter::getRegisterName(Reg); 253 } 254 255 /// PrintPCRelImm - This is used to print an immediate value that ends up 256 /// being encoded as a pc-relative value. These print slightly differently, for 257 /// example, a $ is not emitted. 258 void X86AsmPrinter::PrintPCRelImm(const MachineInstr *MI, unsigned OpNo, 259 raw_ostream &O) { 260 const MachineOperand &MO = MI->getOperand(OpNo); 261 switch (MO.getType()) { 262 default: llvm_unreachable("Unknown pcrel immediate operand"); 263 case MachineOperand::MO_Register: 264 // pc-relativeness was handled when computing the value in the reg. 265 PrintOperand(MI, OpNo, O); 266 return; 267 case MachineOperand::MO_Immediate: 268 O << MO.getImm(); 269 return; 270 case MachineOperand::MO_GlobalAddress: 271 PrintSymbolOperand(MO, O); 272 return; 273 } 274 } 275 276 void X86AsmPrinter::PrintLeaMemReference(const MachineInstr *MI, unsigned OpNo, 277 raw_ostream &O, const char *Modifier) { 278 const MachineOperand &BaseReg = MI->getOperand(OpNo + X86::AddrBaseReg); 279 const MachineOperand &IndexReg = MI->getOperand(OpNo + X86::AddrIndexReg); 280 const MachineOperand &DispSpec = MI->getOperand(OpNo + X86::AddrDisp); 281 282 // If we really don't want to print out (rip), don't. 283 bool HasBaseReg = BaseReg.getReg() != 0; 284 if (HasBaseReg && Modifier && !strcmp(Modifier, "no-rip") && 285 BaseReg.getReg() == X86::RIP) 286 HasBaseReg = false; 287 288 // HasParenPart - True if we will print out the () part of the mem ref. 289 bool HasParenPart = IndexReg.getReg() || HasBaseReg; 290 291 switch (DispSpec.getType()) { 292 default: 293 llvm_unreachable("unknown operand type!"); 294 case MachineOperand::MO_Immediate: { 295 int DispVal = DispSpec.getImm(); 296 if (DispVal || !HasParenPart) 297 O << DispVal; 298 break; 299 } 300 case MachineOperand::MO_GlobalAddress: 301 case MachineOperand::MO_ConstantPoolIndex: 302 PrintSymbolOperand(DispSpec, O); 303 break; 304 } 305 306 if (Modifier && strcmp(Modifier, "H") == 0) 307 O << "+8"; 308 309 if (HasParenPart) { 310 assert(IndexReg.getReg() != X86::ESP && 311 "X86 doesn't allow scaling by ESP"); 312 313 O << '('; 314 if (HasBaseReg) 315 PrintModifiedOperand(MI, OpNo + X86::AddrBaseReg, O, Modifier); 316 317 if (IndexReg.getReg()) { 318 O << ','; 319 PrintModifiedOperand(MI, OpNo + X86::AddrIndexReg, O, Modifier); 320 unsigned ScaleVal = MI->getOperand(OpNo + X86::AddrScaleAmt).getImm(); 321 if (ScaleVal != 1) 322 O << ',' << ScaleVal; 323 } 324 O << ')'; 325 } 326 } 327 328 void X86AsmPrinter::PrintMemReference(const MachineInstr *MI, unsigned OpNo, 329 raw_ostream &O, const char *Modifier) { 330 assert(isMem(*MI, OpNo) && "Invalid memory reference!"); 331 const MachineOperand &Segment = MI->getOperand(OpNo + X86::AddrSegmentReg); 332 if (Segment.getReg()) { 333 PrintModifiedOperand(MI, OpNo + X86::AddrSegmentReg, O, Modifier); 334 O << ':'; 335 } 336 PrintLeaMemReference(MI, OpNo, O, Modifier); 337 } 338 339 void X86AsmPrinter::PrintIntelMemReference(const MachineInstr *MI, 340 unsigned OpNo, raw_ostream &O) { 341 const MachineOperand &BaseReg = MI->getOperand(OpNo + X86::AddrBaseReg); 342 unsigned ScaleVal = MI->getOperand(OpNo + X86::AddrScaleAmt).getImm(); 343 const MachineOperand &IndexReg = MI->getOperand(OpNo + X86::AddrIndexReg); 344 const MachineOperand &DispSpec = MI->getOperand(OpNo + X86::AddrDisp); 345 const MachineOperand &SegReg = MI->getOperand(OpNo + X86::AddrSegmentReg); 346 347 // If this has a segment register, print it. 348 if (SegReg.getReg()) { 349 PrintOperand(MI, OpNo + X86::AddrSegmentReg, O); 350 O << ':'; 351 } 352 353 O << '['; 354 355 bool NeedPlus = false; 356 if (BaseReg.getReg()) { 357 PrintOperand(MI, OpNo + X86::AddrBaseReg, O); 358 NeedPlus = true; 359 } 360 361 if (IndexReg.getReg()) { 362 if (NeedPlus) O << " + "; 363 if (ScaleVal != 1) 364 O << ScaleVal << '*'; 365 PrintOperand(MI, OpNo + X86::AddrIndexReg, O); 366 NeedPlus = true; 367 } 368 369 if (!DispSpec.isImm()) { 370 if (NeedPlus) O << " + "; 371 PrintOperand(MI, OpNo + X86::AddrDisp, O); 372 } else { 373 int64_t DispVal = DispSpec.getImm(); 374 if (DispVal || (!IndexReg.getReg() && !BaseReg.getReg())) { 375 if (NeedPlus) { 376 if (DispVal > 0) 377 O << " + "; 378 else { 379 O << " - "; 380 DispVal = -DispVal; 381 } 382 } 383 O << DispVal; 384 } 385 } 386 O << ']'; 387 } 388 389 static bool printAsmMRegister(X86AsmPrinter &P, const MachineOperand &MO, 390 char Mode, raw_ostream &O) { 391 unsigned Reg = MO.getReg(); 392 bool EmitPercent = true; 393 394 if (!X86::GR8RegClass.contains(Reg) && 395 !X86::GR16RegClass.contains(Reg) && 396 !X86::GR32RegClass.contains(Reg) && 397 !X86::GR64RegClass.contains(Reg)) 398 return true; 399 400 switch (Mode) { 401 default: return true; // Unknown mode. 402 case 'b': // Print QImode register 403 Reg = getX86SubSuperRegister(Reg, 8); 404 break; 405 case 'h': // Print QImode high register 406 Reg = getX86SubSuperRegister(Reg, 8, true); 407 break; 408 case 'w': // Print HImode register 409 Reg = getX86SubSuperRegister(Reg, 16); 410 break; 411 case 'k': // Print SImode register 412 Reg = getX86SubSuperRegister(Reg, 32); 413 break; 414 case 'V': 415 EmitPercent = false; 416 LLVM_FALLTHROUGH; 417 case 'q': 418 // Print 64-bit register names if 64-bit integer registers are available. 419 // Otherwise, print 32-bit register names. 420 Reg = getX86SubSuperRegister(Reg, P.getSubtarget().is64Bit() ? 64 : 32); 421 break; 422 } 423 424 if (EmitPercent) 425 O << '%'; 426 427 O << X86ATTInstPrinter::getRegisterName(Reg); 428 return false; 429 } 430 431 /// PrintAsmOperand - Print out an operand for an inline asm expression. 432 /// 433 bool X86AsmPrinter::PrintAsmOperand(const MachineInstr *MI, unsigned OpNo, 434 const char *ExtraCode, raw_ostream &O) { 435 // Does this asm operand have a single letter operand modifier? 436 if (ExtraCode && ExtraCode[0]) { 437 if (ExtraCode[1] != 0) return true; // Unknown modifier. 438 439 const MachineOperand &MO = MI->getOperand(OpNo); 440 441 switch (ExtraCode[0]) { 442 default: 443 // See if this is a generic print operand 444 return AsmPrinter::PrintAsmOperand(MI, OpNo, ExtraCode, O); 445 case 'a': // This is an address. Currently only 'i' and 'r' are expected. 446 switch (MO.getType()) { 447 default: 448 return true; 449 case MachineOperand::MO_Immediate: 450 O << MO.getImm(); 451 return false; 452 case MachineOperand::MO_ConstantPoolIndex: 453 case MachineOperand::MO_JumpTableIndex: 454 case MachineOperand::MO_ExternalSymbol: 455 llvm_unreachable("unexpected operand type!"); 456 case MachineOperand::MO_GlobalAddress: 457 PrintSymbolOperand(MO, O); 458 if (Subtarget->isPICStyleRIPRel()) 459 O << "(%rip)"; 460 return false; 461 case MachineOperand::MO_Register: 462 O << '('; 463 PrintOperand(MI, OpNo, O); 464 O << ')'; 465 return false; 466 } 467 468 case 'c': // Don't print "$" before a global var name or constant. 469 switch (MO.getType()) { 470 default: 471 PrintOperand(MI, OpNo, O); 472 break; 473 case MachineOperand::MO_Immediate: 474 O << MO.getImm(); 475 break; 476 case MachineOperand::MO_ConstantPoolIndex: 477 case MachineOperand::MO_JumpTableIndex: 478 case MachineOperand::MO_ExternalSymbol: 479 llvm_unreachable("unexpected operand type!"); 480 case MachineOperand::MO_GlobalAddress: 481 PrintSymbolOperand(MO, O); 482 break; 483 } 484 return false; 485 486 case 'A': // Print '*' before a register (it must be a register) 487 if (MO.isReg()) { 488 O << '*'; 489 PrintOperand(MI, OpNo, O); 490 return false; 491 } 492 return true; 493 494 case 'b': // Print QImode register 495 case 'h': // Print QImode high register 496 case 'w': // Print HImode register 497 case 'k': // Print SImode register 498 case 'q': // Print DImode register 499 case 'V': // Print native register without '%' 500 if (MO.isReg()) 501 return printAsmMRegister(*this, MO, ExtraCode[0], O); 502 PrintOperand(MI, OpNo, O); 503 return false; 504 505 case 'P': // This is the operand of a call, treat specially. 506 PrintPCRelImm(MI, OpNo, O); 507 return false; 508 509 case 'n': // Negate the immediate or print a '-' before the operand. 510 // Note: this is a temporary solution. It should be handled target 511 // independently as part of the 'MC' work. 512 if (MO.isImm()) { 513 O << -MO.getImm(); 514 return false; 515 } 516 O << '-'; 517 } 518 } 519 520 PrintOperand(MI, OpNo, O); 521 return false; 522 } 523 524 bool X86AsmPrinter::PrintAsmMemoryOperand(const MachineInstr *MI, unsigned OpNo, 525 const char *ExtraCode, 526 raw_ostream &O) { 527 if (MI->getInlineAsmDialect() == InlineAsm::AD_Intel) { 528 PrintIntelMemReference(MI, OpNo, O); 529 return false; 530 } 531 532 if (ExtraCode && ExtraCode[0]) { 533 if (ExtraCode[1] != 0) return true; // Unknown modifier. 534 535 switch (ExtraCode[0]) { 536 default: return true; // Unknown modifier. 537 case 'b': // Print QImode register 538 case 'h': // Print QImode high register 539 case 'w': // Print HImode register 540 case 'k': // Print SImode register 541 case 'q': // Print SImode register 542 // These only apply to registers, ignore on mem. 543 break; 544 case 'H': 545 PrintMemReference(MI, OpNo, O, "H"); 546 return false; 547 case 'P': // Don't print @PLT, but do print as memory. 548 PrintMemReference(MI, OpNo, O, "no-rip"); 549 return false; 550 } 551 } 552 PrintMemReference(MI, OpNo, O, nullptr); 553 return false; 554 } 555 556 void X86AsmPrinter::EmitStartOfAsmFile(Module &M) { 557 const Triple &TT = TM.getTargetTriple(); 558 559 if (TT.isOSBinFormatELF()) { 560 // Assemble feature flags that may require creation of a note section. 561 unsigned FeatureFlagsAnd = 0; 562 if (M.getModuleFlag("cf-protection-branch")) 563 FeatureFlagsAnd |= ELF::GNU_PROPERTY_X86_FEATURE_1_IBT; 564 if (M.getModuleFlag("cf-protection-return")) 565 FeatureFlagsAnd |= ELF::GNU_PROPERTY_X86_FEATURE_1_SHSTK; 566 567 if (FeatureFlagsAnd) { 568 // Emit a .note.gnu.property section with the flags. 569 if (!TT.isArch32Bit() && !TT.isArch64Bit()) 570 llvm_unreachable("CFProtection used on invalid architecture!"); 571 MCSection *Cur = OutStreamer->getCurrentSectionOnly(); 572 MCSection *Nt = MMI->getContext().getELFSection( 573 ".note.gnu.property", ELF::SHT_NOTE, ELF::SHF_ALLOC); 574 OutStreamer->SwitchSection(Nt); 575 576 // Emitting note header. 577 int WordSize = TT.isArch64Bit() ? 8 : 4; 578 EmitAlignment(WordSize == 4 ? 2 : 3); 579 OutStreamer->EmitIntValue(4, 4 /*size*/); // data size for "GNU\0" 580 OutStreamer->EmitIntValue(8 + WordSize, 4 /*size*/); // Elf_Prop size 581 OutStreamer->EmitIntValue(ELF::NT_GNU_PROPERTY_TYPE_0, 4 /*size*/); 582 OutStreamer->EmitBytes(StringRef("GNU", 4)); // note name 583 584 // Emitting an Elf_Prop for the CET properties. 585 OutStreamer->EmitIntValue(ELF::GNU_PROPERTY_X86_FEATURE_1_AND, 4); 586 OutStreamer->EmitIntValue(4, 4); // data size 587 OutStreamer->EmitIntValue(FeatureFlagsAnd, 4); // data 588 EmitAlignment(WordSize == 4 ? 2 : 3); // padding 589 590 OutStreamer->endSection(Nt); 591 OutStreamer->SwitchSection(Cur); 592 } 593 } 594 595 if (TT.isOSBinFormatMachO()) 596 OutStreamer->SwitchSection(getObjFileLowering().getTextSection()); 597 598 if (TT.isOSBinFormatCOFF()) { 599 // Emit an absolute @feat.00 symbol. This appears to be some kind of 600 // compiler features bitfield read by link.exe. 601 MCSymbol *S = MMI->getContext().getOrCreateSymbol(StringRef("@feat.00")); 602 OutStreamer->BeginCOFFSymbolDef(S); 603 OutStreamer->EmitCOFFSymbolStorageClass(COFF::IMAGE_SYM_CLASS_STATIC); 604 OutStreamer->EmitCOFFSymbolType(COFF::IMAGE_SYM_DTYPE_NULL); 605 OutStreamer->EndCOFFSymbolDef(); 606 int64_t Feat00Flags = 0; 607 608 if (TT.getArch() == Triple::x86) { 609 // According to the PE-COFF spec, the LSB of this value marks the object 610 // for "registered SEH". This means that all SEH handler entry points 611 // must be registered in .sxdata. Use of any unregistered handlers will 612 // cause the process to terminate immediately. LLVM does not know how to 613 // register any SEH handlers, so its object files should be safe. 614 Feat00Flags |= 1; 615 } 616 617 if (M.getModuleFlag("cfguardtable")) 618 Feat00Flags |= 0x800; // Object is CFG-aware. 619 620 OutStreamer->EmitSymbolAttribute(S, MCSA_Global); 621 OutStreamer->EmitAssignment( 622 S, MCConstantExpr::create(Feat00Flags, MMI->getContext())); 623 } 624 OutStreamer->EmitSyntaxDirective(); 625 626 // If this is not inline asm and we're in 16-bit 627 // mode prefix assembly with .code16. 628 bool is16 = TT.getEnvironment() == Triple::CODE16; 629 if (M.getModuleInlineAsm().empty() && is16) 630 OutStreamer->EmitAssemblerFlag(MCAF_Code16); 631 } 632 633 static void 634 emitNonLazySymbolPointer(MCStreamer &OutStreamer, MCSymbol *StubLabel, 635 MachineModuleInfoImpl::StubValueTy &MCSym) { 636 // L_foo$stub: 637 OutStreamer.EmitLabel(StubLabel); 638 // .indirect_symbol _foo 639 OutStreamer.EmitSymbolAttribute(MCSym.getPointer(), MCSA_IndirectSymbol); 640 641 if (MCSym.getInt()) 642 // External to current translation unit. 643 OutStreamer.EmitIntValue(0, 4/*size*/); 644 else 645 // Internal to current translation unit. 646 // 647 // When we place the LSDA into the TEXT section, the type info 648 // pointers need to be indirect and pc-rel. We accomplish this by 649 // using NLPs; however, sometimes the types are local to the file. 650 // We need to fill in the value for the NLP in those cases. 651 OutStreamer.EmitValue( 652 MCSymbolRefExpr::create(MCSym.getPointer(), OutStreamer.getContext()), 653 4 /*size*/); 654 } 655 656 static void emitNonLazyStubs(MachineModuleInfo *MMI, MCStreamer &OutStreamer) { 657 658 MachineModuleInfoMachO &MMIMacho = 659 MMI->getObjFileInfo<MachineModuleInfoMachO>(); 660 661 // Output stubs for dynamically-linked functions. 662 MachineModuleInfoMachO::SymbolListTy Stubs; 663 664 // Output stubs for external and common global variables. 665 Stubs = MMIMacho.GetGVStubList(); 666 if (!Stubs.empty()) { 667 OutStreamer.SwitchSection(MMI->getContext().getMachOSection( 668 "__IMPORT", "__pointers", MachO::S_NON_LAZY_SYMBOL_POINTERS, 669 SectionKind::getMetadata())); 670 671 for (auto &Stub : Stubs) 672 emitNonLazySymbolPointer(OutStreamer, Stub.first, Stub.second); 673 674 Stubs.clear(); 675 OutStreamer.AddBlankLine(); 676 } 677 } 678 679 void X86AsmPrinter::EmitEndOfAsmFile(Module &M) { 680 const Triple &TT = TM.getTargetTriple(); 681 682 if (TT.isOSBinFormatMachO()) { 683 // Mach-O uses non-lazy symbol stubs to encode per-TU information into 684 // global table for symbol lookup. 685 emitNonLazyStubs(MMI, *OutStreamer); 686 687 // Emit stack and fault map information. 688 emitStackMaps(SM); 689 FM.serializeToFaultMapSection(); 690 691 // This flag tells the linker that no global symbols contain code that fall 692 // through to other global symbols (e.g. an implementation of multiple entry 693 // points). If this doesn't occur, the linker can safely perform dead code 694 // stripping. Since LLVM never generates code that does this, it is always 695 // safe to set. 696 OutStreamer->EmitAssemblerFlag(MCAF_SubsectionsViaSymbols); 697 } else if (TT.isOSBinFormatCOFF()) { 698 if (MMI->usesMSVCFloatingPoint()) { 699 // In Windows' libcmt.lib, there is a file which is linked in only if the 700 // symbol _fltused is referenced. Linking this in causes some 701 // side-effects: 702 // 703 // 1. For x86-32, it will set the x87 rounding mode to 53-bit instead of 704 // 64-bit mantissas at program start. 705 // 706 // 2. It links in support routines for floating-point in scanf and printf. 707 // 708 // MSVC emits an undefined reference to _fltused when there are any 709 // floating point operations in the program (including calls). A program 710 // that only has: `scanf("%f", &global_float);` may fail to trigger this, 711 // but oh well...that's a documented issue. 712 StringRef SymbolName = 713 (TT.getArch() == Triple::x86) ? "__fltused" : "_fltused"; 714 MCSymbol *S = MMI->getContext().getOrCreateSymbol(SymbolName); 715 OutStreamer->EmitSymbolAttribute(S, MCSA_Global); 716 return; 717 } 718 emitStackMaps(SM); 719 } else if (TT.isOSBinFormatELF()) { 720 emitStackMaps(SM); 721 FM.serializeToFaultMapSection(); 722 } 723 } 724 725 //===----------------------------------------------------------------------===// 726 // Target Registry Stuff 727 //===----------------------------------------------------------------------===// 728 729 // Force static initialization. 730 extern "C" void LLVMInitializeX86AsmPrinter() { 731 RegisterAsmPrinter<X86AsmPrinter> X(getTheX86_32Target()); 732 RegisterAsmPrinter<X86AsmPrinter> Y(getTheX86_64Target()); 733 } 734