1 //===-- llvm/Target/TargetLoweringObjectFile.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/Target/TargetLoweringObjectFile.h" 16 #include "llvm/Constants.h" 17 #include "llvm/DerivedTypes.h" 18 #include "llvm/GlobalVariable.h" 19 #include "llvm/MC/MCContext.h" 20 #include "llvm/MC/MCSection.h" 21 #include "llvm/Target/TargetMachine.h" 22 #include "llvm/Target/TargetData.h" 23 #include "llvm/Target/TargetOptions.h" 24 #include "llvm/Support/Mangler.h" 25 #include "llvm/ADT/StringExtras.h" 26 using namespace llvm; 27 28 //===----------------------------------------------------------------------===// 29 // Generic Code 30 //===----------------------------------------------------------------------===// 31 32 TargetLoweringObjectFile::TargetLoweringObjectFile() : Ctx(0) { 33 TextSection = 0; 34 DataSection = 0; 35 BSSSection = 0; 36 ReadOnlySection = 0; 37 } 38 39 TargetLoweringObjectFile::~TargetLoweringObjectFile() { 40 } 41 42 static bool isSuitableForBSS(const GlobalVariable *GV) { 43 Constant *C = GV->getInitializer(); 44 45 // Must have zero initializer. 46 if (!C->isNullValue()) 47 return false; 48 49 // Leave constant zeros in readonly constant sections, so they can be shared. 50 if (GV->isConstant()) 51 return false; 52 53 // If the global has an explicit section specified, don't put it in BSS. 54 if (!GV->getSection().empty()) 55 return false; 56 57 // If -nozero-initialized-in-bss is specified, don't ever use BSS. 58 if (NoZerosInBSS) 59 return false; 60 61 // Otherwise, put it in BSS! 62 return true; 63 } 64 65 static bool isConstantString(const Constant *C) { 66 // First check: is we have constant array of i8 terminated with zero 67 const ConstantArray *CVA = dyn_cast<ConstantArray>(C); 68 // Check, if initializer is a null-terminated string 69 if (CVA && CVA->isCString()) 70 return true; 71 72 // Another possibility: [1 x i8] zeroinitializer 73 if (isa<ConstantAggregateZero>(C)) 74 if (const ArrayType *Ty = dyn_cast<ArrayType>(C->getType())) 75 return (Ty->getElementType() == Type::Int8Ty && 76 Ty->getNumElements() == 1); 77 78 return false; 79 } 80 81 /// SectionKindForGlobal - This is a top-level target-independent classifier for 82 /// a global variable. Given an global variable and information from TM, it 83 /// classifies the global in a variety of ways that make various target 84 /// implementations simpler. The target implementation is free to ignore this 85 /// extra info of course. 86 static SectionKind SectionKindForGlobal(const GlobalValue *GV, 87 const TargetMachine &TM) { 88 Reloc::Model ReloModel = TM.getRelocationModel(); 89 90 // Early exit - functions should be always in text sections. 91 const GlobalVariable *GVar = dyn_cast<GlobalVariable>(GV); 92 if (GVar == 0) 93 return SectionKind::getText(); 94 95 96 // Handle thread-local data first. 97 if (GVar->isThreadLocal()) { 98 if (isSuitableForBSS(GVar)) 99 return SectionKind::getThreadBSS(); 100 return SectionKind::getThreadData(); 101 } 102 103 // Variable can be easily put to BSS section. 104 if (isSuitableForBSS(GVar)) 105 return SectionKind::getBSS(); 106 107 Constant *C = GVar->getInitializer(); 108 109 // If the global is marked constant, we can put it into a mergable section, 110 // a mergable string section, or general .data if it contains relocations. 111 if (GVar->isConstant()) { 112 // If the initializer for the global contains something that requires a 113 // relocation, then we may have to drop this into a wriable data section 114 // even though it is marked const. 115 switch (C->getRelocationInfo()) { 116 default: llvm_unreachable("unknown relocation info kind"); 117 case Constant::NoRelocation: 118 // If initializer is a null-terminated string, put it in a "cstring" 119 // section if the target has it. 120 if (isConstantString(C)) 121 return SectionKind::getMergeableCString(); 122 123 // Otherwise, just drop it into a mergable constant section. If we have 124 // a section for this size, use it, otherwise use the arbitrary sized 125 // mergable section. 126 switch (TM.getTargetData()->getTypeAllocSize(C->getType())) { 127 case 4: return SectionKind::getMergeableConst4(); 128 case 8: return SectionKind::getMergeableConst8(); 129 case 16: return SectionKind::getMergeableConst16(); 130 default: return SectionKind::getMergeableConst(); 131 } 132 133 case Constant::LocalRelocation: 134 // In static relocation model, the linker will resolve all addresses, so 135 // the relocation entries will actually be constants by the time the app 136 // starts up. However, we can't put this into a mergable section, because 137 // the linker doesn't take relocations into consideration when it tries to 138 // merge entries in the section. 139 if (ReloModel == Reloc::Static) 140 return SectionKind::getReadOnly(); 141 142 // Otherwise, the dynamic linker needs to fix it up, put it in the 143 // writable data.rel.local section. 144 return SectionKind::getReadOnlyWithRelLocal(); 145 146 case Constant::GlobalRelocations: 147 // In static relocation model, the linker will resolve all addresses, so 148 // the relocation entries will actually be constants by the time the app 149 // starts up. However, we can't put this into a mergable section, because 150 // the linker doesn't take relocations into consideration when it tries to 151 // merge entries in the section. 152 if (ReloModel == Reloc::Static) 153 return SectionKind::getReadOnly(); 154 155 // Otherwise, the dynamic linker needs to fix it up, put it in the 156 // writable data.rel section. 157 return SectionKind::getReadOnlyWithRel(); 158 } 159 } 160 161 // Okay, this isn't a constant. If the initializer for the global is going 162 // to require a runtime relocation by the dynamic linker, put it into a more 163 // specific section to improve startup time of the app. This coalesces these 164 // globals together onto fewer pages, improving the locality of the dynamic 165 // linker. 166 if (ReloModel == Reloc::Static) 167 return SectionKind::getDataNoRel(); 168 169 switch (C->getRelocationInfo()) { 170 default: llvm_unreachable("unknown relocation info kind"); 171 case Constant::NoRelocation: 172 return SectionKind::getDataNoRel(); 173 case Constant::LocalRelocation: 174 return SectionKind::getDataRelLocal(); 175 case Constant::GlobalRelocations: 176 return SectionKind::getDataRel(); 177 } 178 } 179 180 /// SectionForGlobal - This method computes the appropriate section to emit 181 /// the specified global variable or function definition. This should not 182 /// be passed external (or available externally) globals. 183 const MCSection *TargetLoweringObjectFile:: 184 SectionForGlobal(const GlobalValue *GV, Mangler *Mang, 185 const TargetMachine &TM) const { 186 assert(!GV->isDeclaration() && !GV->hasAvailableExternallyLinkage() && 187 "Can only be used for global definitions"); 188 189 SectionKind Kind = SectionKindForGlobal(GV, TM); 190 191 // Select section name. 192 if (GV->hasSection()) { 193 // If the target has special section hacks for specifically named globals, 194 // return them now. 195 if (const MCSection *TS = getSpecialCasedSectionGlobals(GV, Mang, Kind)) 196 return TS; 197 198 // If the target has magic semantics for certain section names, make sure to 199 // pick up the flags. This allows the user to write things with attribute 200 // section and still get the appropriate section flags printed. 201 Kind = getKindForNamedSection(GV->getSection().c_str(), Kind); 202 203 return getOrCreateSection(GV->getSection().c_str(), false, Kind); 204 } 205 206 207 // Use default section depending on the 'type' of global 208 return SelectSectionForGlobal(GV, Kind, Mang, TM); 209 } 210 211 // Lame default implementation. Calculate the section name for global. 212 const MCSection * 213 TargetLoweringObjectFile::SelectSectionForGlobal(const GlobalValue *GV, 214 SectionKind Kind, 215 Mangler *Mang, 216 const TargetMachine &TM) const{ 217 assert(!Kind.isThreadLocal() && "Doesn't support TLS"); 218 219 if (Kind.isText()) 220 return getTextSection(); 221 222 if (Kind.isBSS() && BSSSection != 0) 223 return BSSSection; 224 225 if (Kind.isReadOnly() && ReadOnlySection != 0) 226 return ReadOnlySection; 227 228 return getDataSection(); 229 } 230 231 /// getSectionForConstant - Given a mergable constant with the 232 /// specified size and relocation information, return a section that it 233 /// should be placed in. 234 const MCSection * 235 TargetLoweringObjectFile::getSectionForConstant(SectionKind Kind) const { 236 if (Kind.isReadOnly() && ReadOnlySection != 0) 237 return ReadOnlySection; 238 239 return DataSection; 240 } 241 242 243 const MCSection *TargetLoweringObjectFile:: 244 getOrCreateSection(const char *Name, bool isDirective, SectionKind Kind) const { 245 if (MCSection *S = Ctx->GetSection(Name)) 246 return S; 247 return MCSection::Create(Name, isDirective, Kind, *Ctx); 248 } 249 250 251 252 //===----------------------------------------------------------------------===// 253 // ELF 254 //===----------------------------------------------------------------------===// 255 256 void TargetLoweringObjectFileELF::Initialize(MCContext &Ctx, 257 const TargetMachine &TM) { 258 TargetLoweringObjectFile::Initialize(Ctx, TM); 259 if (!HasCrazyBSS) 260 BSSSection = getOrCreateSection("\t.bss", true, SectionKind::getBSS()); 261 else 262 // PPC/Linux doesn't support the .bss directive, it needs .section .bss. 263 // FIXME: Does .section .bss work everywhere?? 264 // FIXME2: this should just be handle by the section printer. We should get 265 // away from syntactic view of the sections and MCSection should just be a 266 // semantic view. 267 BSSSection = getOrCreateSection("\t.bss", false, SectionKind::getBSS()); 268 269 270 TextSection = getOrCreateSection("\t.text", true, SectionKind::getText()); 271 DataSection = getOrCreateSection("\t.data", true, SectionKind::getDataRel()); 272 ReadOnlySection = 273 getOrCreateSection("\t.rodata", false, SectionKind::getReadOnly()); 274 TLSDataSection = 275 getOrCreateSection("\t.tdata", false, SectionKind::getThreadData()); 276 CStringSection = getOrCreateSection("\t.rodata.str", true, 277 SectionKind::getMergeableCString()); 278 279 TLSBSSSection = getOrCreateSection("\t.tbss", false, 280 SectionKind::getThreadBSS()); 281 282 DataRelSection = getOrCreateSection("\t.data.rel", false, 283 SectionKind::getDataRel()); 284 DataRelLocalSection = getOrCreateSection("\t.data.rel.local", false, 285 SectionKind::getDataRelLocal()); 286 DataRelROSection = getOrCreateSection("\t.data.rel.ro", false, 287 SectionKind::getReadOnlyWithRel()); 288 DataRelROLocalSection = 289 getOrCreateSection("\t.data.rel.ro.local", false, 290 SectionKind::getReadOnlyWithRelLocal()); 291 292 MergeableConst4Section = getOrCreateSection(".rodata.cst4", false, 293 SectionKind::getMergeableConst4()); 294 MergeableConst8Section = getOrCreateSection(".rodata.cst8", false, 295 SectionKind::getMergeableConst8()); 296 MergeableConst16Section = getOrCreateSection(".rodata.cst16", false, 297 SectionKind::getMergeableConst16()); 298 } 299 300 301 SectionKind TargetLoweringObjectFileELF:: 302 getKindForNamedSection(const char *Name, SectionKind K) const { 303 if (Name[0] != '.') return K; 304 305 // Some lame default implementation based on some magic section names. 306 if (strncmp(Name, ".gnu.linkonce.b.", 16) == 0 || 307 strncmp(Name, ".llvm.linkonce.b.", 17) == 0 || 308 strncmp(Name, ".gnu.linkonce.sb.", 17) == 0 || 309 strncmp(Name, ".llvm.linkonce.sb.", 18) == 0) 310 return SectionKind::getBSS(); 311 312 if (strcmp(Name, ".tdata") == 0 || 313 strncmp(Name, ".tdata.", 7) == 0 || 314 strncmp(Name, ".gnu.linkonce.td.", 17) == 0 || 315 strncmp(Name, ".llvm.linkonce.td.", 18) == 0) 316 return SectionKind::getThreadData(); 317 318 if (strcmp(Name, ".tbss") == 0 || 319 strncmp(Name, ".tbss.", 6) == 0 || 320 strncmp(Name, ".gnu.linkonce.tb.", 17) == 0 || 321 strncmp(Name, ".llvm.linkonce.tb.", 18) == 0) 322 return SectionKind::getThreadBSS(); 323 324 return K; 325 } 326 327 void TargetLoweringObjectFileELF:: 328 getSectionFlagsAsString(SectionKind Kind, SmallVectorImpl<char> &Str) const { 329 Str.push_back(','); 330 Str.push_back('"'); 331 332 if (!Kind.isMetadata()) 333 Str.push_back('a'); 334 if (Kind.isText()) 335 Str.push_back('x'); 336 if (Kind.isWriteable()) 337 Str.push_back('w'); 338 if (Kind.isMergeableCString() || 339 Kind.isMergeableConst4() || 340 Kind.isMergeableConst8() || 341 Kind.isMergeableConst16()) 342 Str.push_back('M'); 343 if (Kind.isMergeableCString()) 344 Str.push_back('S'); 345 if (Kind.isThreadLocal()) 346 Str.push_back('T'); 347 348 Str.push_back('"'); 349 Str.push_back(','); 350 351 // If comment string is '@', e.g. as on ARM - use '%' instead 352 if (AtIsCommentChar) 353 Str.push_back('%'); 354 else 355 Str.push_back('@'); 356 357 const char *KindStr; 358 if (Kind.isBSS() || Kind.isThreadBSS()) 359 KindStr = "nobits"; 360 else 361 KindStr = "progbits"; 362 363 Str.append(KindStr, KindStr+strlen(KindStr)); 364 365 if (Kind.isMergeableCString()) { 366 // TODO: Eventually handle multiple byte character strings. For now, all 367 // mergable C strings are single byte. 368 Str.push_back(','); 369 Str.push_back('1'); 370 } else if (Kind.isMergeableConst4()) { 371 Str.push_back(','); 372 Str.push_back('4'); 373 } else if (Kind.isMergeableConst8()) { 374 Str.push_back(','); 375 Str.push_back('8'); 376 } else if (Kind.isMergeableConst16()) { 377 Str.push_back(','); 378 Str.push_back('1'); 379 Str.push_back('6'); 380 } 381 } 382 383 384 static const char *getSectionPrefixForUniqueGlobal(SectionKind Kind) { 385 if (Kind.isText()) return ".gnu.linkonce.t."; 386 if (Kind.isReadOnly()) return ".gnu.linkonce.r."; 387 388 if (Kind.isThreadData()) return ".gnu.linkonce.td."; 389 if (Kind.isThreadBSS()) return ".gnu.linkonce.tb."; 390 391 if (Kind.isBSS()) return ".gnu.linkonce.b."; 392 if (Kind.isDataNoRel()) return ".gnu.linkonce.d."; 393 if (Kind.isDataRelLocal()) return ".gnu.linkonce.d.rel.local."; 394 if (Kind.isDataRel()) return ".gnu.linkonce.d.rel."; 395 if (Kind.isReadOnlyWithRelLocal()) return ".gnu.linkonce.d.rel.ro.local."; 396 397 assert(Kind.isReadOnlyWithRel() && "Unknown section kind"); 398 return ".gnu.linkonce.d.rel.ro."; 399 } 400 401 const MCSection *TargetLoweringObjectFileELF:: 402 SelectSectionForGlobal(const GlobalValue *GV, SectionKind Kind, 403 Mangler *Mang, const TargetMachine &TM) const { 404 405 // If this global is linkonce/weak and the target handles this by emitting it 406 // into a 'uniqued' section name, create and return the section now. 407 if (GV->isWeakForLinker()) { 408 const char *Prefix = getSectionPrefixForUniqueGlobal(Kind); 409 std::string Name = Mang->makeNameProper(GV->getNameStr()); 410 return getOrCreateSection((Prefix+Name).c_str(), false, Kind); 411 } 412 413 if (Kind.isText()) return TextSection; 414 415 if (Kind.isMergeableCString()) { 416 assert(CStringSection && "Should have string section prefix"); 417 418 // We also need alignment here. 419 // FIXME: this is getting the alignment of the character, not the 420 // alignment of the global! 421 unsigned Align = 422 TM.getTargetData()->getPreferredAlignment(cast<GlobalVariable>(GV)); 423 424 std::string Name = CStringSection->getName() + "1." + utostr(Align); 425 return getOrCreateSection(Name.c_str(), false, 426 SectionKind::getMergeableCString()); 427 } 428 429 if (Kind.isMergeableConst()) { 430 if (Kind.isMergeableConst4()) 431 return MergeableConst4Section; 432 if (Kind.isMergeableConst8()) 433 return MergeableConst8Section; 434 if (Kind.isMergeableConst16()) 435 return MergeableConst16Section; 436 return ReadOnlySection; // .const 437 } 438 439 if (Kind.isReadOnly()) return ReadOnlySection; 440 441 if (Kind.isThreadData()) return TLSDataSection; 442 if (Kind.isThreadBSS()) return TLSBSSSection; 443 444 if (Kind.isBSS()) return BSSSection; 445 446 if (Kind.isDataNoRel()) return DataSection; 447 if (Kind.isDataRelLocal()) return DataRelLocalSection; 448 if (Kind.isDataRel()) return DataRelSection; 449 if (Kind.isReadOnlyWithRelLocal()) return DataRelROLocalSection; 450 451 assert(Kind.isReadOnlyWithRel() && "Unknown section kind"); 452 return DataRelROSection; 453 } 454 455 /// getSectionForConstant - Given a mergeable constant with the 456 /// specified size and relocation information, return a section that it 457 /// should be placed in. 458 const MCSection *TargetLoweringObjectFileELF:: 459 getSectionForConstant(SectionKind Kind) const { 460 if (Kind.isMergeableConst4()) 461 return MergeableConst4Section; 462 if (Kind.isMergeableConst8()) 463 return MergeableConst8Section; 464 if (Kind.isMergeableConst16()) 465 return MergeableConst16Section; 466 if (Kind.isReadOnly()) 467 return ReadOnlySection; 468 469 if (Kind.isReadOnlyWithRelLocal()) return DataRelROLocalSection; 470 assert(Kind.isReadOnlyWithRel() && "Unknown section kind"); 471 return DataRelROSection; 472 } 473 474 //===----------------------------------------------------------------------===// 475 // MachO 476 //===----------------------------------------------------------------------===// 477 478 void TargetLoweringObjectFileMachO::Initialize(MCContext &Ctx, 479 const TargetMachine &TM) { 480 TargetLoweringObjectFile::Initialize(Ctx, TM); 481 TextSection = getOrCreateSection("\t.text", true, 482 SectionKind::getText()); 483 DataSection = getOrCreateSection("\t.data", true, 484 SectionKind::getDataRel()); 485 486 CStringSection = getOrCreateSection("\t.cstring", true, 487 SectionKind::getMergeableCString()); 488 FourByteConstantSection = getOrCreateSection("\t.literal4\n", true, 489 SectionKind::getMergeableConst4()); 490 EightByteConstantSection = getOrCreateSection("\t.literal8\n", true, 491 SectionKind::getMergeableConst8()); 492 493 // ld_classic doesn't support .literal16 in 32-bit mode, and ld64 falls back 494 // to using it in -static mode. 495 if (TM.getRelocationModel() != Reloc::Static && 496 TM.getTargetData()->getPointerSize() == 32) 497 SixteenByteConstantSection = 498 getOrCreateSection("\t.literal16\n", true, 499 SectionKind::getMergeableConst16()); 500 else 501 SixteenByteConstantSection = 0; 502 503 ReadOnlySection = getOrCreateSection("\t.const", true, 504 SectionKind::getReadOnly()); 505 506 TextCoalSection = 507 getOrCreateSection("\t__TEXT,__textcoal_nt,coalesced,pure_instructions", 508 false, SectionKind::getText()); 509 ConstTextCoalSection = getOrCreateSection("\t__TEXT,__const_coal,coalesced", 510 false, 511 SectionKind::getText()); 512 ConstDataCoalSection = getOrCreateSection("\t__DATA,__const_coal,coalesced", 513 false, 514 SectionKind::getText()); 515 ConstDataSection = getOrCreateSection("\t.const_data", true, 516 SectionKind::getReadOnlyWithRel()); 517 DataCoalSection = getOrCreateSection("\t__DATA,__datacoal_nt,coalesced", 518 false, 519 SectionKind::getDataRel()); 520 } 521 522 const MCSection *TargetLoweringObjectFileMachO:: 523 SelectSectionForGlobal(const GlobalValue *GV, SectionKind Kind, 524 Mangler *Mang, const TargetMachine &TM) const { 525 assert(!Kind.isThreadLocal() && "Darwin doesn't support TLS"); 526 527 if (Kind.isText()) 528 return GV->isWeakForLinker() ? TextCoalSection : TextSection; 529 530 // If this is weak/linkonce, put this in a coalescable section, either in text 531 // or data depending on if it is writable. 532 if (GV->isWeakForLinker()) { 533 if (Kind.isReadOnly()) 534 return ConstTextCoalSection; 535 return DataCoalSection; 536 } 537 538 // FIXME: Alignment check should be handled by section classifier. 539 if (Kind.isMergeableCString()) { 540 Constant *C = cast<GlobalVariable>(GV)->getInitializer(); 541 const Type *Ty = cast<ArrayType>(C->getType())->getElementType(); 542 const TargetData &TD = *TM.getTargetData(); 543 unsigned Size = TD.getTypeAllocSize(Ty); 544 if (Size) { 545 unsigned Align = TD.getPreferredAlignment(cast<GlobalVariable>(GV)); 546 if (Align <= 32) 547 return CStringSection; 548 } 549 550 return ReadOnlySection; 551 } 552 553 if (Kind.isMergeableConst()) { 554 if (Kind.isMergeableConst4()) 555 return FourByteConstantSection; 556 if (Kind.isMergeableConst8()) 557 return EightByteConstantSection; 558 if (Kind.isMergeableConst16() && SixteenByteConstantSection) 559 return SixteenByteConstantSection; 560 return ReadOnlySection; // .const 561 } 562 563 // FIXME: ROData -> const in -static mode that is relocatable but they happen 564 // by the static linker. Why not mergeable? 565 if (Kind.isReadOnly()) 566 return ReadOnlySection; 567 568 // If this is marked const, put it into a const section. But if the dynamic 569 // linker needs to write to it, put it in the data segment. 570 if (Kind.isReadOnlyWithRel()) 571 return ConstDataSection; 572 573 // Otherwise, just drop the variable in the normal data section. 574 return DataSection; 575 } 576 577 const MCSection * 578 TargetLoweringObjectFileMachO::getSectionForConstant(SectionKind Kind) const { 579 // If this constant requires a relocation, we have to put it in the data 580 // segment, not in the text segment. 581 if (Kind.isDataRel()) 582 return ConstDataSection; 583 584 if (Kind.isMergeableConst4()) 585 return FourByteConstantSection; 586 if (Kind.isMergeableConst8()) 587 return EightByteConstantSection; 588 if (Kind.isMergeableConst16() && SixteenByteConstantSection) 589 return SixteenByteConstantSection; 590 return ReadOnlySection; // .const 591 } 592 593 /// shouldEmitUsedDirectiveFor - This hook allows targets to selectively decide 594 /// not to emit the UsedDirective for some symbols in llvm.used. 595 // FIXME: REMOVE this (rdar://7071300) 596 bool TargetLoweringObjectFileMachO:: 597 shouldEmitUsedDirectiveFor(const GlobalValue *GV, Mangler *Mang) const { 598 /// On Darwin, internally linked data beginning with "L" or "l" does not have 599 /// the directive emitted (this occurs in ObjC metadata). 600 if (!GV) return false; 601 602 // Check whether the mangled name has the "Private" or "LinkerPrivate" prefix. 603 if (GV->hasLocalLinkage() && !isa<Function>(GV)) { 604 // FIXME: ObjC metadata is currently emitted as internal symbols that have 605 // \1L and \0l prefixes on them. Fix them to be Private/LinkerPrivate and 606 // this horrible hack can go away. 607 const std::string &Name = Mang->getMangledName(GV); 608 if (Name[0] == 'L' || Name[0] == 'l') 609 return false; 610 } 611 612 return true; 613 } 614 615 616 //===----------------------------------------------------------------------===// 617 // COFF 618 //===----------------------------------------------------------------------===// 619 620 void TargetLoweringObjectFileCOFF::Initialize(MCContext &Ctx, 621 const TargetMachine &TM) { 622 TargetLoweringObjectFile::Initialize(Ctx, TM); 623 TextSection = getOrCreateSection("\t.text", true, 624 SectionKind::getText()); 625 DataSection = getOrCreateSection("\t.data", true, 626 SectionKind::getDataRel()); 627 } 628 629 void TargetLoweringObjectFileCOFF:: 630 getSectionFlagsAsString(SectionKind Kind, SmallVectorImpl<char> &Str) const { 631 // FIXME: Inefficient. 632 std::string Res = ",\""; 633 if (Kind.isText()) 634 Res += 'x'; 635 if (Kind.isWriteable()) 636 Res += 'w'; 637 Res += "\""; 638 639 Str.append(Res.begin(), Res.end()); 640 } 641 642 static const char *getCOFFSectionPrefixForUniqueGlobal(SectionKind Kind) { 643 if (Kind.isText()) 644 return ".text$linkonce"; 645 if (Kind.isWriteable()) 646 return ".data$linkonce"; 647 return ".rdata$linkonce"; 648 } 649 650 651 const MCSection *TargetLoweringObjectFileCOFF:: 652 SelectSectionForGlobal(const GlobalValue *GV, SectionKind Kind, 653 Mangler *Mang, const TargetMachine &TM) const { 654 assert(!Kind.isThreadLocal() && "Doesn't support TLS"); 655 656 // If this global is linkonce/weak and the target handles this by emitting it 657 // into a 'uniqued' section name, create and return the section now. 658 if (GV->isWeakForLinker()) { 659 const char *Prefix = getCOFFSectionPrefixForUniqueGlobal(Kind); 660 std::string Name = Mang->makeNameProper(GV->getNameStr()); 661 return getOrCreateSection((Prefix+Name).c_str(), false, Kind); 662 } 663 664 if (Kind.isText()) 665 return getTextSection(); 666 667 return getDataSection(); 668 } 669 670