TargetLoweringObjectFileImpl.cpp revision f8597eb0d94c66c8b4f3dc3b1ccf175417707776
1//===-- llvm/CodeGen/TargetLoweringObjectFileImpl.cpp - Object File Info --===// 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 classes used to handle lowerings specific to common 11// object file formats. 12// 13//===----------------------------------------------------------------------===// 14 15#include "llvm/CodeGen/TargetLoweringObjectFileImpl.h" 16#include "llvm/Constants.h" 17#include "llvm/DerivedTypes.h" 18#include "llvm/Function.h" 19#include "llvm/GlobalVariable.h" 20#include "llvm/CodeGen/MachineModuleInfoImpls.h" 21#include "llvm/MC/MCContext.h" 22#include "llvm/MC/MCExpr.h" 23#include "llvm/MC/MCSectionMachO.h" 24#include "llvm/MC/MCSectionELF.h" 25#include "llvm/MC/MCSectionCOFF.h" 26#include "llvm/MC/MCSymbol.h" 27#include "llvm/Target/Mangler.h" 28#include "llvm/Target/TargetData.h" 29#include "llvm/Target/TargetMachine.h" 30#include "llvm/Target/TargetOptions.h" 31#include "llvm/Support/Dwarf.h" 32#include "llvm/Support/ELF.h" 33#include "llvm/Support/ErrorHandling.h" 34#include "llvm/Support/raw_ostream.h" 35#include "llvm/ADT/SmallString.h" 36#include "llvm/ADT/StringExtras.h" 37#include "llvm/ADT/Triple.h" 38using namespace llvm; 39using namespace dwarf; 40 41//===----------------------------------------------------------------------===// 42// ELF 43//===----------------------------------------------------------------------===// 44 45void TargetLoweringObjectFileELF::Initialize(MCContext &Ctx, 46 const TargetMachine &TM) { 47 TargetLoweringObjectFile::Initialize(Ctx, TM); 48 49 BSSSection = 50 getContext().getELFSection(".bss", ELF::SHT_NOBITS, 51 ELF::SHF_WRITE |ELF::SHF_ALLOC, 52 SectionKind::getBSS()); 53 54 TextSection = 55 getContext().getELFSection(".text", ELF::SHT_PROGBITS, 56 ELF::SHF_EXECINSTR | 57 ELF::SHF_ALLOC, 58 SectionKind::getText()); 59 60 DataSection = 61 getContext().getELFSection(".data", ELF::SHT_PROGBITS, 62 ELF::SHF_WRITE |ELF::SHF_ALLOC, 63 SectionKind::getDataRel()); 64 65 ReadOnlySection = 66 getContext().getELFSection(".rodata", ELF::SHT_PROGBITS, 67 ELF::SHF_ALLOC, 68 SectionKind::getReadOnly()); 69 70 TLSDataSection = 71 getContext().getELFSection(".tdata", ELF::SHT_PROGBITS, 72 ELF::SHF_ALLOC | ELF::SHF_TLS | 73 ELF::SHF_WRITE, 74 SectionKind::getThreadData()); 75 76 TLSBSSSection = 77 getContext().getELFSection(".tbss", ELF::SHT_NOBITS, 78 ELF::SHF_ALLOC | ELF::SHF_TLS | 79 ELF::SHF_WRITE, 80 SectionKind::getThreadBSS()); 81 82 DataRelSection = 83 getContext().getELFSection(".data.rel", ELF::SHT_PROGBITS, 84 ELF::SHF_ALLOC |ELF::SHF_WRITE, 85 SectionKind::getDataRel()); 86 87 DataRelLocalSection = 88 getContext().getELFSection(".data.rel.local", ELF::SHT_PROGBITS, 89 ELF::SHF_ALLOC |ELF::SHF_WRITE, 90 SectionKind::getDataRelLocal()); 91 92 DataRelROSection = 93 getContext().getELFSection(".data.rel.ro", ELF::SHT_PROGBITS, 94 ELF::SHF_ALLOC |ELF::SHF_WRITE, 95 SectionKind::getReadOnlyWithRel()); 96 97 DataRelROLocalSection = 98 getContext().getELFSection(".data.rel.ro.local", ELF::SHT_PROGBITS, 99 ELF::SHF_ALLOC |ELF::SHF_WRITE, 100 SectionKind::getReadOnlyWithRelLocal()); 101 102 MergeableConst4Section = 103 getContext().getELFSection(".rodata.cst4", ELF::SHT_PROGBITS, 104 ELF::SHF_ALLOC |ELF::SHF_MERGE, 105 SectionKind::getMergeableConst4()); 106 107 MergeableConst8Section = 108 getContext().getELFSection(".rodata.cst8", ELF::SHT_PROGBITS, 109 ELF::SHF_ALLOC |ELF::SHF_MERGE, 110 SectionKind::getMergeableConst8()); 111 112 MergeableConst16Section = 113 getContext().getELFSection(".rodata.cst16", ELF::SHT_PROGBITS, 114 ELF::SHF_ALLOC |ELF::SHF_MERGE, 115 SectionKind::getMergeableConst16()); 116 117 StaticCtorSection = 118 getContext().getELFSection(".ctors", ELF::SHT_PROGBITS, 119 ELF::SHF_ALLOC |ELF::SHF_WRITE, 120 SectionKind::getDataRel()); 121 122 StaticDtorSection = 123 getContext().getELFSection(".dtors", ELF::SHT_PROGBITS, 124 ELF::SHF_ALLOC |ELF::SHF_WRITE, 125 SectionKind::getDataRel()); 126 127 // Exception Handling Sections. 128 129 // FIXME: We're emitting LSDA info into a readonly section on ELF, even though 130 // it contains relocatable pointers. In PIC mode, this is probably a big 131 // runtime hit for C++ apps. Either the contents of the LSDA need to be 132 // adjusted or this should be a data section. 133 LSDASection = 134 getContext().getELFSection(".gcc_except_table", ELF::SHT_PROGBITS, 135 ELF::SHF_ALLOC, 136 SectionKind::getReadOnly()); 137 // Debug Info Sections. 138 DwarfAbbrevSection = 139 getContext().getELFSection(".debug_abbrev", ELF::SHT_PROGBITS, 0, 140 SectionKind::getMetadata()); 141 DwarfInfoSection = 142 getContext().getELFSection(".debug_info", ELF::SHT_PROGBITS, 0, 143 SectionKind::getMetadata()); 144 DwarfLineSection = 145 getContext().getELFSection(".debug_line", ELF::SHT_PROGBITS, 0, 146 SectionKind::getMetadata()); 147 DwarfFrameSection = 148 getContext().getELFSection(".debug_frame", ELF::SHT_PROGBITS, 0, 149 SectionKind::getMetadata()); 150 DwarfPubNamesSection = 151 getContext().getELFSection(".debug_pubnames", ELF::SHT_PROGBITS, 0, 152 SectionKind::getMetadata()); 153 DwarfPubTypesSection = 154 getContext().getELFSection(".debug_pubtypes", ELF::SHT_PROGBITS, 0, 155 SectionKind::getMetadata()); 156 DwarfStrSection = 157 getContext().getELFSection(".debug_str", ELF::SHT_PROGBITS, 0, 158 SectionKind::getMetadata()); 159 DwarfLocSection = 160 getContext().getELFSection(".debug_loc", ELF::SHT_PROGBITS, 0, 161 SectionKind::getMetadata()); 162 DwarfARangesSection = 163 getContext().getELFSection(".debug_aranges", ELF::SHT_PROGBITS, 0, 164 SectionKind::getMetadata()); 165 DwarfRangesSection = 166 getContext().getELFSection(".debug_ranges", ELF::SHT_PROGBITS, 0, 167 SectionKind::getMetadata()); 168 DwarfMacroInfoSection = 169 getContext().getELFSection(".debug_macinfo", ELF::SHT_PROGBITS, 0, 170 SectionKind::getMetadata()); 171} 172 173const MCSection *TargetLoweringObjectFileELF::getEHFrameSection() const { 174 return getContext().getELFSection(".eh_frame", ELF::SHT_PROGBITS, 175 ELF::SHF_ALLOC, 176 SectionKind::getDataRel()); 177} 178 179static SectionKind 180getELFKindForNamedSection(StringRef Name, SectionKind K) { 181 if (Name.empty() || Name[0] != '.') return K; 182 183 // Some lame default implementation based on some magic section names. 184 if (Name == ".bss" || 185 Name.startswith(".bss.") || 186 Name.startswith(".gnu.linkonce.b.") || 187 Name.startswith(".llvm.linkonce.b.") || 188 Name == ".sbss" || 189 Name.startswith(".sbss.") || 190 Name.startswith(".gnu.linkonce.sb.") || 191 Name.startswith(".llvm.linkonce.sb.")) 192 return SectionKind::getBSS(); 193 194 if (Name == ".tdata" || 195 Name.startswith(".tdata.") || 196 Name.startswith(".gnu.linkonce.td.") || 197 Name.startswith(".llvm.linkonce.td.")) 198 return SectionKind::getThreadData(); 199 200 if (Name == ".tbss" || 201 Name.startswith(".tbss.") || 202 Name.startswith(".gnu.linkonce.tb.") || 203 Name.startswith(".llvm.linkonce.tb.")) 204 return SectionKind::getThreadBSS(); 205 206 return K; 207} 208 209 210static unsigned getELFSectionType(StringRef Name, SectionKind K) { 211 212 if (Name == ".init_array") 213 return ELF::SHT_INIT_ARRAY; 214 215 if (Name == ".fini_array") 216 return ELF::SHT_FINI_ARRAY; 217 218 if (Name == ".preinit_array") 219 return ELF::SHT_PREINIT_ARRAY; 220 221 if (K.isBSS() || K.isThreadBSS()) 222 return ELF::SHT_NOBITS; 223 224 return ELF::SHT_PROGBITS; 225} 226 227 228static unsigned 229getELFSectionFlags(SectionKind K) { 230 unsigned Flags = 0; 231 232 if (!K.isMetadata()) 233 Flags |= ELF::SHF_ALLOC; 234 235 if (K.isText()) 236 Flags |= ELF::SHF_EXECINSTR; 237 238 if (K.isWriteable()) 239 Flags |= ELF::SHF_WRITE; 240 241 if (K.isThreadLocal()) 242 Flags |= ELF::SHF_TLS; 243 244 // K.isMergeableConst() is left out to honour PR4650 245 if (K.isMergeableCString() || K.isMergeableConst4() || 246 K.isMergeableConst8() || K.isMergeableConst16()) 247 Flags |= ELF::SHF_MERGE; 248 249 if (K.isMergeableCString()) 250 Flags |= ELF::SHF_STRINGS; 251 252 return Flags; 253} 254 255 256const MCSection *TargetLoweringObjectFileELF:: 257getExplicitSectionGlobal(const GlobalValue *GV, SectionKind Kind, 258 Mangler *Mang, const TargetMachine &TM) const { 259 StringRef SectionName = GV->getSection(); 260 261 // Infer section flags from the section name if we can. 262 Kind = getELFKindForNamedSection(SectionName, Kind); 263 264 return getContext().getELFSection(SectionName, 265 getELFSectionType(SectionName, Kind), 266 getELFSectionFlags(Kind), Kind); 267} 268 269/// getSectionPrefixForGlobal - Return the section prefix name used by options 270/// FunctionsSections and DataSections. 271static const char *getSectionPrefixForGlobal(SectionKind Kind) { 272 if (Kind.isText()) return ".text."; 273 if (Kind.isReadOnly()) return ".rodata."; 274 275 if (Kind.isThreadData()) return ".tdata."; 276 if (Kind.isThreadBSS()) return ".tbss."; 277 278 if (Kind.isDataNoRel()) return ".data."; 279 if (Kind.isDataRelLocal()) return ".data.rel.local."; 280 if (Kind.isDataRel()) return ".data.rel."; 281 if (Kind.isReadOnlyWithRelLocal()) return ".data.rel.ro.local."; 282 283 assert(Kind.isReadOnlyWithRel() && "Unknown section kind"); 284 return ".data.rel.ro."; 285} 286 287 288const MCSection *TargetLoweringObjectFileELF:: 289SelectSectionForGlobal(const GlobalValue *GV, SectionKind Kind, 290 Mangler *Mang, const TargetMachine &TM) const { 291 // If we have -ffunction-section or -fdata-section then we should emit the 292 // global value to a uniqued section specifically for it. 293 bool EmitUniquedSection; 294 if (Kind.isText()) 295 EmitUniquedSection = TM.getFunctionSections(); 296 else 297 EmitUniquedSection = TM.getDataSections(); 298 299 // If this global is linkonce/weak and the target handles this by emitting it 300 // into a 'uniqued' section name, create and return the section now. 301 if ((GV->isWeakForLinker() || EmitUniquedSection) && 302 !Kind.isCommon() && !Kind.isBSS()) { 303 const char *Prefix; 304 Prefix = getSectionPrefixForGlobal(Kind); 305 306 SmallString<128> Name(Prefix, Prefix+strlen(Prefix)); 307 MCSymbol *Sym = Mang->getSymbol(GV); 308 Name.append(Sym->getName().begin(), Sym->getName().end()); 309 StringRef Group = ""; 310 unsigned Flags = getELFSectionFlags(Kind); 311 if (GV->isWeakForLinker()) { 312 Group = Sym->getName(); 313 Flags |= ELF::SHF_GROUP; 314 } 315 316 return getContext().getELFSection(Name.str(), 317 getELFSectionType(Name.str(), Kind), 318 Flags, Kind, 0, Group); 319 } 320 321 if (Kind.isText()) return TextSection; 322 323 if (Kind.isMergeable1ByteCString() || 324 Kind.isMergeable2ByteCString() || 325 Kind.isMergeable4ByteCString()) { 326 327 // We also need alignment here. 328 // FIXME: this is getting the alignment of the character, not the 329 // alignment of the global! 330 unsigned Align = 331 TM.getTargetData()->getPreferredAlignment(cast<GlobalVariable>(GV)); 332 333 const char *SizeSpec = ".rodata.str1."; 334 if (Kind.isMergeable2ByteCString()) 335 SizeSpec = ".rodata.str2."; 336 else if (Kind.isMergeable4ByteCString()) 337 SizeSpec = ".rodata.str4."; 338 else 339 assert(Kind.isMergeable1ByteCString() && "unknown string width"); 340 341 342 std::string Name = SizeSpec + utostr(Align); 343 return getContext().getELFSection(Name, ELF::SHT_PROGBITS, 344 ELF::SHF_ALLOC | 345 ELF::SHF_MERGE | 346 ELF::SHF_STRINGS, 347 Kind); 348 } 349 350 if (Kind.isMergeableConst()) { 351 if (Kind.isMergeableConst4() && MergeableConst4Section) 352 return MergeableConst4Section; 353 if (Kind.isMergeableConst8() && MergeableConst8Section) 354 return MergeableConst8Section; 355 if (Kind.isMergeableConst16() && MergeableConst16Section) 356 return MergeableConst16Section; 357 return ReadOnlySection; // .const 358 } 359 360 if (Kind.isReadOnly()) return ReadOnlySection; 361 362 if (Kind.isThreadData()) return TLSDataSection; 363 if (Kind.isThreadBSS()) return TLSBSSSection; 364 365 // Note: we claim that common symbols are put in BSSSection, but they are 366 // really emitted with the magic .comm directive, which creates a symbol table 367 // entry but not a section. 368 if (Kind.isBSS() || Kind.isCommon()) return BSSSection; 369 370 if (Kind.isDataNoRel()) return DataSection; 371 if (Kind.isDataRelLocal()) return DataRelLocalSection; 372 if (Kind.isDataRel()) return DataRelSection; 373 if (Kind.isReadOnlyWithRelLocal()) return DataRelROLocalSection; 374 375 assert(Kind.isReadOnlyWithRel() && "Unknown section kind"); 376 return DataRelROSection; 377} 378 379/// getSectionForConstant - Given a mergeable constant with the 380/// specified size and relocation information, return a section that it 381/// should be placed in. 382const MCSection *TargetLoweringObjectFileELF:: 383getSectionForConstant(SectionKind Kind) const { 384 if (Kind.isMergeableConst4() && MergeableConst4Section) 385 return MergeableConst4Section; 386 if (Kind.isMergeableConst8() && MergeableConst8Section) 387 return MergeableConst8Section; 388 if (Kind.isMergeableConst16() && MergeableConst16Section) 389 return MergeableConst16Section; 390 if (Kind.isReadOnly()) 391 return ReadOnlySection; 392 393 if (Kind.isReadOnlyWithRelLocal()) return DataRelROLocalSection; 394 assert(Kind.isReadOnlyWithRel() && "Unknown section kind"); 395 return DataRelROSection; 396} 397 398const MCExpr *TargetLoweringObjectFileELF:: 399getExprForDwarfGlobalReference(const GlobalValue *GV, Mangler *Mang, 400 MachineModuleInfo *MMI, 401 unsigned Encoding, MCStreamer &Streamer) const { 402 403 if (Encoding & dwarf::DW_EH_PE_indirect) { 404 MachineModuleInfoELF &ELFMMI = MMI->getObjFileInfo<MachineModuleInfoELF>(); 405 406 SmallString<128> Name; 407 Mang->getNameWithPrefix(Name, GV, true); 408 Name += ".DW.stub"; 409 410 // Add information about the stub reference to ELFMMI so that the stub 411 // gets emitted by the asmprinter. 412 MCSymbol *SSym = getContext().GetOrCreateSymbol(Name.str()); 413 MachineModuleInfoImpl::StubValueTy &StubSym = ELFMMI.getGVStubEntry(SSym); 414 if (StubSym.getPointer() == 0) { 415 MCSymbol *Sym = Mang->getSymbol(GV); 416 StubSym = MachineModuleInfoImpl::StubValueTy(Sym, !GV->hasLocalLinkage()); 417 } 418 419 return TargetLoweringObjectFile:: 420 getExprForDwarfReference(SSym, Mang, MMI, 421 Encoding & ~dwarf::DW_EH_PE_indirect, Streamer); 422 } 423 424 return TargetLoweringObjectFile:: 425 getExprForDwarfGlobalReference(GV, Mang, MMI, Encoding, Streamer); 426} 427 428//===----------------------------------------------------------------------===// 429// MachO 430//===----------------------------------------------------------------------===// 431 432void TargetLoweringObjectFileMachO::Initialize(MCContext &Ctx, 433 const TargetMachine &TM) { 434 // _foo.eh symbols are currently always exported so that the linker knows 435 // about them. This is not necessary on 10.6 and later, but it 436 // doesn't hurt anything. 437 // FIXME: I need to get this from Triple. 438 IsFunctionEHSymbolGlobal = true; 439 IsFunctionEHFrameSymbolPrivate = false; 440 SupportsWeakOmittedEHFrame = false; 441 442 Triple T(((LLVMTargetMachine&)TM).getTargetTriple()); 443 if (T.getOS() == Triple::Darwin) { 444 switch (T.getDarwinMajorNumber()) { 445 case 7: // 10.3 Panther. 446 case 8: // 10.4 Tiger. 447 CommDirectiveSupportsAlignment = false; 448 break; 449 case 9: // 10.5 Leopard. 450 case 10: // 10.6 SnowLeopard. 451 break; 452 } 453 } 454 455 TargetLoweringObjectFile::Initialize(Ctx, TM); 456 457 TextSection // .text 458 = getContext().getMachOSection("__TEXT", "__text", 459 MCSectionMachO::S_ATTR_PURE_INSTRUCTIONS, 460 SectionKind::getText()); 461 DataSection // .data 462 = getContext().getMachOSection("__DATA", "__data", 0, 463 SectionKind::getDataRel()); 464 465 TLSDataSection // .tdata 466 = getContext().getMachOSection("__DATA", "__thread_data", 467 MCSectionMachO::S_THREAD_LOCAL_REGULAR, 468 SectionKind::getDataRel()); 469 TLSBSSSection // .tbss 470 = getContext().getMachOSection("__DATA", "__thread_bss", 471 MCSectionMachO::S_THREAD_LOCAL_ZEROFILL, 472 SectionKind::getThreadBSS()); 473 474 // TODO: Verify datarel below. 475 TLSTLVSection // .tlv 476 = getContext().getMachOSection("__DATA", "__thread_vars", 477 MCSectionMachO::S_THREAD_LOCAL_VARIABLES, 478 SectionKind::getDataRel()); 479 480 TLSThreadInitSection 481 = getContext().getMachOSection("__DATA", "__thread_init", 482 MCSectionMachO::S_THREAD_LOCAL_INIT_FUNCTION_POINTERS, 483 SectionKind::getDataRel()); 484 485 CStringSection // .cstring 486 = getContext().getMachOSection("__TEXT", "__cstring", 487 MCSectionMachO::S_CSTRING_LITERALS, 488 SectionKind::getMergeable1ByteCString()); 489 UStringSection 490 = getContext().getMachOSection("__TEXT","__ustring", 0, 491 SectionKind::getMergeable2ByteCString()); 492 FourByteConstantSection // .literal4 493 = getContext().getMachOSection("__TEXT", "__literal4", 494 MCSectionMachO::S_4BYTE_LITERALS, 495 SectionKind::getMergeableConst4()); 496 EightByteConstantSection // .literal8 497 = getContext().getMachOSection("__TEXT", "__literal8", 498 MCSectionMachO::S_8BYTE_LITERALS, 499 SectionKind::getMergeableConst8()); 500 501 // ld_classic doesn't support .literal16 in 32-bit mode, and ld64 falls back 502 // to using it in -static mode. 503 SixteenByteConstantSection = 0; 504 if (TM.getRelocationModel() != Reloc::Static && 505 TM.getTargetData()->getPointerSize() == 32) 506 SixteenByteConstantSection = // .literal16 507 getContext().getMachOSection("__TEXT", "__literal16", 508 MCSectionMachO::S_16BYTE_LITERALS, 509 SectionKind::getMergeableConst16()); 510 511 ReadOnlySection // .const 512 = getContext().getMachOSection("__TEXT", "__const", 0, 513 SectionKind::getReadOnly()); 514 515 TextCoalSection 516 = getContext().getMachOSection("__TEXT", "__textcoal_nt", 517 MCSectionMachO::S_COALESCED | 518 MCSectionMachO::S_ATTR_PURE_INSTRUCTIONS, 519 SectionKind::getText()); 520 ConstTextCoalSection 521 = getContext().getMachOSection("__TEXT", "__const_coal", 522 MCSectionMachO::S_COALESCED, 523 SectionKind::getReadOnly()); 524 ConstDataSection // .const_data 525 = getContext().getMachOSection("__DATA", "__const", 0, 526 SectionKind::getReadOnlyWithRel()); 527 DataCoalSection 528 = getContext().getMachOSection("__DATA","__datacoal_nt", 529 MCSectionMachO::S_COALESCED, 530 SectionKind::getDataRel()); 531 DataCommonSection 532 = getContext().getMachOSection("__DATA","__common", 533 MCSectionMachO::S_ZEROFILL, 534 SectionKind::getBSS()); 535 DataBSSSection 536 = getContext().getMachOSection("__DATA","__bss", MCSectionMachO::S_ZEROFILL, 537 SectionKind::getBSS()); 538 539 540 LazySymbolPointerSection 541 = getContext().getMachOSection("__DATA", "__la_symbol_ptr", 542 MCSectionMachO::S_LAZY_SYMBOL_POINTERS, 543 SectionKind::getMetadata()); 544 NonLazySymbolPointerSection 545 = getContext().getMachOSection("__DATA", "__nl_symbol_ptr", 546 MCSectionMachO::S_NON_LAZY_SYMBOL_POINTERS, 547 SectionKind::getMetadata()); 548 549 if (TM.getRelocationModel() == Reloc::Static) { 550 StaticCtorSection 551 = getContext().getMachOSection("__TEXT", "__constructor", 0, 552 SectionKind::getDataRel()); 553 StaticDtorSection 554 = getContext().getMachOSection("__TEXT", "__destructor", 0, 555 SectionKind::getDataRel()); 556 } else { 557 StaticCtorSection 558 = getContext().getMachOSection("__DATA", "__mod_init_func", 559 MCSectionMachO::S_MOD_INIT_FUNC_POINTERS, 560 SectionKind::getDataRel()); 561 StaticDtorSection 562 = getContext().getMachOSection("__DATA", "__mod_term_func", 563 MCSectionMachO::S_MOD_TERM_FUNC_POINTERS, 564 SectionKind::getDataRel()); 565 } 566 567 // Exception Handling. 568 LSDASection = getContext().getMachOSection("__TEXT", "__gcc_except_tab", 0, 569 SectionKind::getReadOnlyWithRel()); 570 // Debug Information. 571 DwarfAbbrevSection = 572 getContext().getMachOSection("__DWARF", "__debug_abbrev", 573 MCSectionMachO::S_ATTR_DEBUG, 574 SectionKind::getMetadata()); 575 DwarfInfoSection = 576 getContext().getMachOSection("__DWARF", "__debug_info", 577 MCSectionMachO::S_ATTR_DEBUG, 578 SectionKind::getMetadata()); 579 DwarfLineSection = 580 getContext().getMachOSection("__DWARF", "__debug_line", 581 MCSectionMachO::S_ATTR_DEBUG, 582 SectionKind::getMetadata()); 583 DwarfFrameSection = 584 getContext().getMachOSection("__DWARF", "__debug_frame", 585 MCSectionMachO::S_ATTR_DEBUG, 586 SectionKind::getMetadata()); 587 DwarfPubNamesSection = 588 getContext().getMachOSection("__DWARF", "__debug_pubnames", 589 MCSectionMachO::S_ATTR_DEBUG, 590 SectionKind::getMetadata()); 591 DwarfPubTypesSection = 592 getContext().getMachOSection("__DWARF", "__debug_pubtypes", 593 MCSectionMachO::S_ATTR_DEBUG, 594 SectionKind::getMetadata()); 595 DwarfStrSection = 596 getContext().getMachOSection("__DWARF", "__debug_str", 597 MCSectionMachO::S_ATTR_DEBUG, 598 SectionKind::getMetadata()); 599 DwarfLocSection = 600 getContext().getMachOSection("__DWARF", "__debug_loc", 601 MCSectionMachO::S_ATTR_DEBUG, 602 SectionKind::getMetadata()); 603 DwarfARangesSection = 604 getContext().getMachOSection("__DWARF", "__debug_aranges", 605 MCSectionMachO::S_ATTR_DEBUG, 606 SectionKind::getMetadata()); 607 DwarfRangesSection = 608 getContext().getMachOSection("__DWARF", "__debug_ranges", 609 MCSectionMachO::S_ATTR_DEBUG, 610 SectionKind::getMetadata()); 611 DwarfMacroInfoSection = 612 getContext().getMachOSection("__DWARF", "__debug_macinfo", 613 MCSectionMachO::S_ATTR_DEBUG, 614 SectionKind::getMetadata()); 615 DwarfDebugInlineSection = 616 getContext().getMachOSection("__DWARF", "__debug_inlined", 617 MCSectionMachO::S_ATTR_DEBUG, 618 SectionKind::getMetadata()); 619 620 TLSExtraDataSection = TLSTLVSection; 621} 622 623const MCSection *TargetLoweringObjectFileMachO::getEHFrameSection() const { 624 return getContext().getMachOSection("__TEXT", "__eh_frame", 625 MCSectionMachO::S_COALESCED | 626 MCSectionMachO::S_ATTR_NO_TOC | 627 MCSectionMachO::S_ATTR_STRIP_STATIC_SYMS | 628 MCSectionMachO::S_ATTR_LIVE_SUPPORT, 629 SectionKind::getReadOnly()); 630} 631 632const MCSection *TargetLoweringObjectFileMachO:: 633getExplicitSectionGlobal(const GlobalValue *GV, SectionKind Kind, 634 Mangler *Mang, const TargetMachine &TM) const { 635 // Parse the section specifier and create it if valid. 636 StringRef Segment, Section; 637 unsigned TAA = (unsigned)MCSectionMachO::SECTION_ATTRIBUTES, StubSize = 0; 638 std::string ErrorCode = 639 MCSectionMachO::ParseSectionSpecifier(GV->getSection(), Segment, Section, 640 TAA, StubSize); 641 if (!ErrorCode.empty()) { 642 // If invalid, report the error with report_fatal_error. 643 report_fatal_error("Global variable '" + GV->getNameStr() + 644 "' has an invalid section specifier '" + GV->getSection()+ 645 "': " + ErrorCode + "."); 646 // Fall back to dropping it into the data section. 647 return DataSection; 648 } 649 650 bool TAAWasSet = (TAA != MCSectionMachO::SECTION_ATTRIBUTES); 651 if (!TAAWasSet) 652 TAA = 0; // Sensible default if this is a new section. 653 654 // Get the section. 655 const MCSectionMachO *S = 656 getContext().getMachOSection(Segment, Section, TAA, StubSize, Kind); 657 658 // If TAA wasn't set by ParseSectionSpecifier() above, 659 // use the value returned by getMachOSection() as a default. 660 if (!TAAWasSet) 661 TAA = S->getTypeAndAttributes(); 662 663 // Okay, now that we got the section, verify that the TAA & StubSize agree. 664 // If the user declared multiple globals with different section flags, we need 665 // to reject it here. 666 if (S->getTypeAndAttributes() != TAA || S->getStubSize() != StubSize) { 667 // If invalid, report the error with report_fatal_error. 668 report_fatal_error("Global variable '" + GV->getNameStr() + 669 "' section type or attributes does not match previous" 670 " section specifier"); 671 } 672 673 return S; 674} 675 676const MCSection *TargetLoweringObjectFileMachO:: 677SelectSectionForGlobal(const GlobalValue *GV, SectionKind Kind, 678 Mangler *Mang, const TargetMachine &TM) const { 679 680 // Handle thread local data. 681 if (Kind.isThreadBSS()) return TLSBSSSection; 682 if (Kind.isThreadData()) return TLSDataSection; 683 684 if (Kind.isText()) 685 return GV->isWeakForLinker() ? TextCoalSection : TextSection; 686 687 // If this is weak/linkonce, put this in a coalescable section, either in text 688 // or data depending on if it is writable. 689 if (GV->isWeakForLinker()) { 690 if (Kind.isReadOnly()) 691 return ConstTextCoalSection; 692 return DataCoalSection; 693 } 694 695 // FIXME: Alignment check should be handled by section classifier. 696 if (Kind.isMergeable1ByteCString() && 697 TM.getTargetData()->getPreferredAlignment(cast<GlobalVariable>(GV)) < 32) 698 return CStringSection; 699 700 // Do not put 16-bit arrays in the UString section if they have an 701 // externally visible label, this runs into issues with certain linker 702 // versions. 703 if (Kind.isMergeable2ByteCString() && !GV->hasExternalLinkage() && 704 TM.getTargetData()->getPreferredAlignment(cast<GlobalVariable>(GV)) < 32) 705 return UStringSection; 706 707 if (Kind.isMergeableConst()) { 708 if (Kind.isMergeableConst4()) 709 return FourByteConstantSection; 710 if (Kind.isMergeableConst8()) 711 return EightByteConstantSection; 712 if (Kind.isMergeableConst16() && SixteenByteConstantSection) 713 return SixteenByteConstantSection; 714 } 715 716 // Otherwise, if it is readonly, but not something we can specially optimize, 717 // just drop it in .const. 718 if (Kind.isReadOnly()) 719 return ReadOnlySection; 720 721 // If this is marked const, put it into a const section. But if the dynamic 722 // linker needs to write to it, put it in the data segment. 723 if (Kind.isReadOnlyWithRel()) 724 return ConstDataSection; 725 726 // Put zero initialized globals with strong external linkage in the 727 // DATA, __common section with the .zerofill directive. 728 if (Kind.isBSSExtern()) 729 return DataCommonSection; 730 731 // Put zero initialized globals with local linkage in __DATA,__bss directive 732 // with the .zerofill directive (aka .lcomm). 733 if (Kind.isBSSLocal()) 734 return DataBSSSection; 735 736 // Otherwise, just drop the variable in the normal data section. 737 return DataSection; 738} 739 740const MCSection * 741TargetLoweringObjectFileMachO::getSectionForConstant(SectionKind Kind) const { 742 // If this constant requires a relocation, we have to put it in the data 743 // segment, not in the text segment. 744 if (Kind.isDataRel() || Kind.isReadOnlyWithRel()) 745 return ConstDataSection; 746 747 if (Kind.isMergeableConst4()) 748 return FourByteConstantSection; 749 if (Kind.isMergeableConst8()) 750 return EightByteConstantSection; 751 if (Kind.isMergeableConst16() && SixteenByteConstantSection) 752 return SixteenByteConstantSection; 753 return ReadOnlySection; // .const 754} 755 756/// shouldEmitUsedDirectiveFor - This hook allows targets to selectively decide 757/// not to emit the UsedDirective for some symbols in llvm.used. 758// FIXME: REMOVE this (rdar://7071300) 759bool TargetLoweringObjectFileMachO:: 760shouldEmitUsedDirectiveFor(const GlobalValue *GV, Mangler *Mang) const { 761 /// On Darwin, internally linked data beginning with "L" or "l" does not have 762 /// the directive emitted (this occurs in ObjC metadata). 763 if (!GV) return false; 764 765 // Check whether the mangled name has the "Private" or "LinkerPrivate" prefix. 766 if (GV->hasLocalLinkage() && !isa<Function>(GV)) { 767 // FIXME: ObjC metadata is currently emitted as internal symbols that have 768 // \1L and \0l prefixes on them. Fix them to be Private/LinkerPrivate and 769 // this horrible hack can go away. 770 MCSymbol *Sym = Mang->getSymbol(GV); 771 if (Sym->getName()[0] == 'L' || Sym->getName()[0] == 'l') 772 return false; 773 } 774 775 return true; 776} 777 778const MCExpr *TargetLoweringObjectFileMachO:: 779getExprForDwarfGlobalReference(const GlobalValue *GV, Mangler *Mang, 780 MachineModuleInfo *MMI, unsigned Encoding, 781 MCStreamer &Streamer) const { 782 // The mach-o version of this method defaults to returning a stub reference. 783 784 if (Encoding & DW_EH_PE_indirect) { 785 MachineModuleInfoMachO &MachOMMI = 786 MMI->getObjFileInfo<MachineModuleInfoMachO>(); 787 788 SmallString<128> Name; 789 Mang->getNameWithPrefix(Name, GV, true); 790 Name += "$non_lazy_ptr"; 791 792 // Add information about the stub reference to MachOMMI so that the stub 793 // gets emitted by the asmprinter. 794 MCSymbol *SSym = getContext().GetOrCreateSymbol(Name.str()); 795 MachineModuleInfoImpl::StubValueTy &StubSym = MachOMMI.getGVStubEntry(SSym); 796 if (StubSym.getPointer() == 0) { 797 MCSymbol *Sym = Mang->getSymbol(GV); 798 StubSym = MachineModuleInfoImpl::StubValueTy(Sym, !GV->hasLocalLinkage()); 799 } 800 801 return TargetLoweringObjectFile:: 802 getExprForDwarfReference(SSym, Mang, MMI, 803 Encoding & ~dwarf::DW_EH_PE_indirect, Streamer); 804 } 805 806 return TargetLoweringObjectFile:: 807 getExprForDwarfGlobalReference(GV, Mang, MMI, Encoding, Streamer); 808} 809 810unsigned TargetLoweringObjectFileMachO::getPersonalityEncoding() const { 811 return DW_EH_PE_indirect | DW_EH_PE_pcrel | DW_EH_PE_sdata4; 812} 813 814unsigned TargetLoweringObjectFileMachO::getLSDAEncoding() const { 815 return DW_EH_PE_pcrel; 816} 817 818unsigned TargetLoweringObjectFileMachO::getFDEEncoding() const { 819 return DW_EH_PE_pcrel; 820} 821 822unsigned TargetLoweringObjectFileMachO::getTTypeEncoding() const { 823 return DW_EH_PE_indirect | DW_EH_PE_pcrel | DW_EH_PE_sdata4; 824} 825 826//===----------------------------------------------------------------------===// 827// COFF 828//===----------------------------------------------------------------------===// 829 830void TargetLoweringObjectFileCOFF::Initialize(MCContext &Ctx, 831 const TargetMachine &TM) { 832 TargetLoweringObjectFile::Initialize(Ctx, TM); 833 TextSection = 834 getContext().getCOFFSection(".text", 835 COFF::IMAGE_SCN_CNT_CODE | 836 COFF::IMAGE_SCN_MEM_EXECUTE | 837 COFF::IMAGE_SCN_MEM_READ, 838 SectionKind::getText()); 839 DataSection = 840 getContext().getCOFFSection(".data", 841 COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | 842 COFF::IMAGE_SCN_MEM_READ | 843 COFF::IMAGE_SCN_MEM_WRITE, 844 SectionKind::getDataRel()); 845 ReadOnlySection = 846 getContext().getCOFFSection(".rdata", 847 COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | 848 COFF::IMAGE_SCN_MEM_READ, 849 SectionKind::getReadOnly()); 850 StaticCtorSection = 851 getContext().getCOFFSection(".ctors", 852 COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | 853 COFF::IMAGE_SCN_MEM_READ | 854 COFF::IMAGE_SCN_MEM_WRITE, 855 SectionKind::getDataRel()); 856 StaticDtorSection = 857 getContext().getCOFFSection(".dtors", 858 COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | 859 COFF::IMAGE_SCN_MEM_READ | 860 COFF::IMAGE_SCN_MEM_WRITE, 861 SectionKind::getDataRel()); 862 863 // FIXME: We're emitting LSDA info into a readonly section on COFF, even 864 // though it contains relocatable pointers. In PIC mode, this is probably a 865 // big runtime hit for C++ apps. Either the contents of the LSDA need to be 866 // adjusted or this should be a data section. 867 LSDASection = 868 getContext().getCOFFSection(".gcc_except_table", 869 COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | 870 COFF::IMAGE_SCN_MEM_READ, 871 SectionKind::getReadOnly()); 872 // Debug info. 873 DwarfAbbrevSection = 874 getContext().getCOFFSection(".debug_abbrev", 875 COFF::IMAGE_SCN_MEM_DISCARDABLE | 876 COFF::IMAGE_SCN_MEM_READ, 877 SectionKind::getMetadata()); 878 DwarfInfoSection = 879 getContext().getCOFFSection(".debug_info", 880 COFF::IMAGE_SCN_MEM_DISCARDABLE | 881 COFF::IMAGE_SCN_MEM_READ, 882 SectionKind::getMetadata()); 883 DwarfLineSection = 884 getContext().getCOFFSection(".debug_line", 885 COFF::IMAGE_SCN_MEM_DISCARDABLE | 886 COFF::IMAGE_SCN_MEM_READ, 887 SectionKind::getMetadata()); 888 DwarfFrameSection = 889 getContext().getCOFFSection(".debug_frame", 890 COFF::IMAGE_SCN_MEM_DISCARDABLE | 891 COFF::IMAGE_SCN_MEM_READ, 892 SectionKind::getMetadata()); 893 DwarfPubNamesSection = 894 getContext().getCOFFSection(".debug_pubnames", 895 COFF::IMAGE_SCN_MEM_DISCARDABLE | 896 COFF::IMAGE_SCN_MEM_READ, 897 SectionKind::getMetadata()); 898 DwarfPubTypesSection = 899 getContext().getCOFFSection(".debug_pubtypes", 900 COFF::IMAGE_SCN_MEM_DISCARDABLE | 901 COFF::IMAGE_SCN_MEM_READ, 902 SectionKind::getMetadata()); 903 DwarfStrSection = 904 getContext().getCOFFSection(".debug_str", 905 COFF::IMAGE_SCN_MEM_DISCARDABLE | 906 COFF::IMAGE_SCN_MEM_READ, 907 SectionKind::getMetadata()); 908 DwarfLocSection = 909 getContext().getCOFFSection(".debug_loc", 910 COFF::IMAGE_SCN_MEM_DISCARDABLE | 911 COFF::IMAGE_SCN_MEM_READ, 912 SectionKind::getMetadata()); 913 DwarfARangesSection = 914 getContext().getCOFFSection(".debug_aranges", 915 COFF::IMAGE_SCN_MEM_DISCARDABLE | 916 COFF::IMAGE_SCN_MEM_READ, 917 SectionKind::getMetadata()); 918 DwarfRangesSection = 919 getContext().getCOFFSection(".debug_ranges", 920 COFF::IMAGE_SCN_MEM_DISCARDABLE | 921 COFF::IMAGE_SCN_MEM_READ, 922 SectionKind::getMetadata()); 923 DwarfMacroInfoSection = 924 getContext().getCOFFSection(".debug_macinfo", 925 COFF::IMAGE_SCN_MEM_DISCARDABLE | 926 COFF::IMAGE_SCN_MEM_READ, 927 SectionKind::getMetadata()); 928 929 DrectveSection = 930 getContext().getCOFFSection(".drectve", 931 COFF::IMAGE_SCN_LNK_INFO, 932 SectionKind::getMetadata()); 933} 934 935const MCSection *TargetLoweringObjectFileCOFF::getEHFrameSection() const { 936 return getContext().getCOFFSection(".eh_frame", 937 COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | 938 COFF::IMAGE_SCN_MEM_READ | 939 COFF::IMAGE_SCN_MEM_WRITE, 940 SectionKind::getDataRel()); 941} 942 943 944static unsigned 945getCOFFSectionFlags(SectionKind K) { 946 unsigned Flags = 0; 947 948 if (K.isMetadata()) 949 Flags |= 950 COFF::IMAGE_SCN_MEM_DISCARDABLE; 951 else if (K.isText()) 952 Flags |= 953 COFF::IMAGE_SCN_MEM_EXECUTE | 954 COFF::IMAGE_SCN_MEM_READ | 955 COFF::IMAGE_SCN_CNT_CODE; 956 else if (K.isBSS ()) 957 Flags |= 958 COFF::IMAGE_SCN_CNT_UNINITIALIZED_DATA | 959 COFF::IMAGE_SCN_MEM_READ | 960 COFF::IMAGE_SCN_MEM_WRITE; 961 else if (K.isReadOnly()) 962 Flags |= 963 COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | 964 COFF::IMAGE_SCN_MEM_READ; 965 else if (K.isWriteable()) 966 Flags |= 967 COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | 968 COFF::IMAGE_SCN_MEM_READ | 969 COFF::IMAGE_SCN_MEM_WRITE; 970 971 return Flags; 972} 973 974const MCSection *TargetLoweringObjectFileCOFF:: 975getExplicitSectionGlobal(const GlobalValue *GV, SectionKind Kind, 976 Mangler *Mang, const TargetMachine &TM) const { 977 return getContext().getCOFFSection(GV->getSection(), 978 getCOFFSectionFlags(Kind), 979 Kind); 980} 981 982static const char *getCOFFSectionPrefixForUniqueGlobal(SectionKind Kind) { 983 if (Kind.isText()) 984 return ".text$"; 985 if (Kind.isBSS ()) 986 return ".bss$"; 987 if (Kind.isWriteable()) 988 return ".data$"; 989 return ".rdata$"; 990} 991 992 993const MCSection *TargetLoweringObjectFileCOFF:: 994SelectSectionForGlobal(const GlobalValue *GV, SectionKind Kind, 995 Mangler *Mang, const TargetMachine &TM) const { 996 assert(!Kind.isThreadLocal() && "Doesn't support TLS"); 997 998 // If this global is linkonce/weak and the target handles this by emitting it 999 // into a 'uniqued' section name, create and return the section now. 1000 if (GV->isWeakForLinker()) { 1001 const char *Prefix = getCOFFSectionPrefixForUniqueGlobal(Kind); 1002 SmallString<128> Name(Prefix, Prefix+strlen(Prefix)); 1003 MCSymbol *Sym = Mang->getSymbol(GV); 1004 Name.append(Sym->getName().begin() + 1, Sym->getName().end()); 1005 1006 unsigned Characteristics = getCOFFSectionFlags(Kind); 1007 1008 Characteristics |= COFF::IMAGE_SCN_LNK_COMDAT; 1009 1010 return getContext().getCOFFSection(Name.str(), Characteristics, 1011 COFF::IMAGE_COMDAT_SELECT_ANY, Kind); 1012 } 1013 1014 if (Kind.isText()) 1015 return getTextSection(); 1016 1017 return getDataSection(); 1018} 1019 1020