1 //===--- CodeGenModule.cpp - Emit LLVM Code from ASTs for a Module --------===// 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 coordinates the per-module state used while generating code. 11 // 12 //===----------------------------------------------------------------------===// 13 14 #include "CodeGenModule.h" 15 #include "CGDebugInfo.h" 16 #include "CodeGenFunction.h" 17 #include "CodeGenTBAA.h" 18 #include "CGCall.h" 19 #include "CGCXXABI.h" 20 #include "CGObjCRuntime.h" 21 #include "Mangle.h" 22 #include "TargetInfo.h" 23 #include "clang/Frontend/CodeGenOptions.h" 24 #include "clang/AST/ASTContext.h" 25 #include "clang/AST/CharUnits.h" 26 #include "clang/AST/DeclObjC.h" 27 #include "clang/AST/DeclCXX.h" 28 #include "clang/AST/DeclTemplate.h" 29 #include "clang/AST/RecordLayout.h" 30 #include "clang/Basic/Builtins.h" 31 #include "clang/Basic/Diagnostic.h" 32 #include "clang/Basic/SourceManager.h" 33 #include "clang/Basic/TargetInfo.h" 34 #include "clang/Basic/ConvertUTF.h" 35 #include "llvm/CallingConv.h" 36 #include "llvm/Module.h" 37 #include "llvm/Intrinsics.h" 38 #include "llvm/LLVMContext.h" 39 #include "llvm/ADT/Triple.h" 40 #include "llvm/Target/TargetData.h" 41 #include "llvm/Support/CallSite.h" 42 #include "llvm/Support/ErrorHandling.h" 43 using namespace clang; 44 using namespace CodeGen; 45 46 static CGCXXABI &createCXXABI(CodeGenModule &CGM) { 47 switch (CGM.getContext().Target.getCXXABI()) { 48 case CXXABI_ARM: return *CreateARMCXXABI(CGM); 49 case CXXABI_Itanium: return *CreateItaniumCXXABI(CGM); 50 case CXXABI_Microsoft: return *CreateMicrosoftCXXABI(CGM); 51 } 52 53 llvm_unreachable("invalid C++ ABI kind"); 54 return *CreateItaniumCXXABI(CGM); 55 } 56 57 58 CodeGenModule::CodeGenModule(ASTContext &C, const CodeGenOptions &CGO, 59 llvm::Module &M, const llvm::TargetData &TD, 60 Diagnostic &diags) 61 : BlockModule(C, M, TD, Types, *this), Context(C), 62 Features(C.getLangOptions()), CodeGenOpts(CGO), TheModule(M), 63 TheTargetData(TD), TheTargetCodeGenInfo(0), Diags(diags), 64 ABI(createCXXABI(*this)), 65 Types(C, M, TD, getTargetCodeGenInfo().getABIInfo(), ABI), 66 TBAA(0), 67 VTables(*this), Runtime(0), 68 CFConstantStringClassRef(0), ConstantStringClassRef(0), 69 VMContext(M.getContext()), 70 NSConcreteGlobalBlockDecl(0), NSConcreteStackBlockDecl(0), 71 NSConcreteGlobalBlock(0), NSConcreteStackBlock(0), 72 BlockObjectAssignDecl(0), BlockObjectDisposeDecl(0), 73 BlockObjectAssign(0), BlockObjectDispose(0){ 74 75 if (!Features.ObjC1) 76 Runtime = 0; 77 else if (!Features.NeXTRuntime) 78 Runtime = CreateGNUObjCRuntime(*this); 79 else if (Features.ObjCNonFragileABI) 80 Runtime = CreateMacNonFragileABIObjCRuntime(*this); 81 else 82 Runtime = CreateMacObjCRuntime(*this); 83 84 // Enable TBAA unless it's suppressed. 85 if (!CodeGenOpts.RelaxedAliasing && CodeGenOpts.OptimizationLevel > 0) 86 TBAA = new CodeGenTBAA(Context, VMContext, getLangOptions(), 87 ABI.getMangleContext()); 88 89 // If debug info generation is enabled, create the CGDebugInfo object. 90 DebugInfo = CodeGenOpts.DebugInfo ? new CGDebugInfo(*this) : 0; 91 } 92 93 CodeGenModule::~CodeGenModule() { 94 delete Runtime; 95 delete &ABI; 96 delete TBAA; 97 delete DebugInfo; 98 } 99 100 void CodeGenModule::createObjCRuntime() { 101 if (!Features.NeXTRuntime) 102 Runtime = CreateGNUObjCRuntime(*this); 103 else if (Features.ObjCNonFragileABI) 104 Runtime = CreateMacNonFragileABIObjCRuntime(*this); 105 else 106 Runtime = CreateMacObjCRuntime(*this); 107 } 108 109 void CodeGenModule::Release() { 110 EmitDeferred(); 111 EmitCXXGlobalInitFunc(); 112 EmitCXXGlobalDtorFunc(); 113 if (Runtime) 114 if (llvm::Function *ObjCInitFunction = Runtime->ModuleInitFunction()) 115 AddGlobalCtor(ObjCInitFunction); 116 EmitCtorList(GlobalCtors, "llvm.global_ctors"); 117 EmitCtorList(GlobalDtors, "llvm.global_dtors"); 118 EmitAnnotations(); 119 EmitLLVMUsed(); 120 121 SimplifyPersonality(); 122 123 if (getCodeGenOpts().EmitDeclMetadata) 124 EmitDeclMetadata(); 125 } 126 127 llvm::MDNode *CodeGenModule::getTBAAInfo(QualType QTy) { 128 if (!TBAA) 129 return 0; 130 return TBAA->getTBAAInfo(QTy); 131 } 132 133 void CodeGenModule::DecorateInstruction(llvm::Instruction *Inst, 134 llvm::MDNode *TBAAInfo) { 135 Inst->setMetadata(llvm::LLVMContext::MD_tbaa, TBAAInfo); 136 } 137 138 bool CodeGenModule::isTargetDarwin() const { 139 return getContext().Target.getTriple().getOS() == llvm::Triple::Darwin; 140 } 141 142 /// ErrorUnsupported - Print out an error that codegen doesn't support the 143 /// specified stmt yet. 144 void CodeGenModule::ErrorUnsupported(const Stmt *S, const char *Type, 145 bool OmitOnError) { 146 if (OmitOnError && getDiags().hasErrorOccurred()) 147 return; 148 unsigned DiagID = getDiags().getCustomDiagID(Diagnostic::Error, 149 "cannot compile this %0 yet"); 150 std::string Msg = Type; 151 getDiags().Report(Context.getFullLoc(S->getLocStart()), DiagID) 152 << Msg << S->getSourceRange(); 153 } 154 155 /// ErrorUnsupported - Print out an error that codegen doesn't support the 156 /// specified decl yet. 157 void CodeGenModule::ErrorUnsupported(const Decl *D, const char *Type, 158 bool OmitOnError) { 159 if (OmitOnError && getDiags().hasErrorOccurred()) 160 return; 161 unsigned DiagID = getDiags().getCustomDiagID(Diagnostic::Error, 162 "cannot compile this %0 yet"); 163 std::string Msg = Type; 164 getDiags().Report(Context.getFullLoc(D->getLocation()), DiagID) << Msg; 165 } 166 167 static llvm::GlobalValue::VisibilityTypes GetLLVMVisibility(Visibility V) { 168 switch (V) { 169 case DefaultVisibility: return llvm::GlobalValue::DefaultVisibility; 170 case HiddenVisibility: return llvm::GlobalValue::HiddenVisibility; 171 case ProtectedVisibility: return llvm::GlobalValue::ProtectedVisibility; 172 } 173 llvm_unreachable("unknown visibility!"); 174 return llvm::GlobalValue::DefaultVisibility; 175 } 176 177 178 void CodeGenModule::setGlobalVisibility(llvm::GlobalValue *GV, 179 const NamedDecl *D, 180 bool IsForDefinition) const { 181 // Internal definitions always have default visibility. 182 if (GV->hasLocalLinkage()) { 183 GV->setVisibility(llvm::GlobalValue::DefaultVisibility); 184 return; 185 } 186 187 // Set visibility for definitions. 188 NamedDecl::LinkageInfo LV = D->getLinkageAndVisibility(); 189 if (LV.visibilityExplicit() || 190 (IsForDefinition && !GV->hasAvailableExternallyLinkage())) 191 GV->setVisibility(GetLLVMVisibility(LV.visibility())); 192 } 193 194 /// Set the symbol visibility of type information (vtable and RTTI) 195 /// associated with the given type. 196 void CodeGenModule::setTypeVisibility(llvm::GlobalValue *GV, 197 const CXXRecordDecl *RD, 198 bool IsForRTTI, 199 bool IsForDefinition) const { 200 setGlobalVisibility(GV, RD, IsForDefinition); 201 202 if (!CodeGenOpts.HiddenWeakVTables) 203 return; 204 205 // We want to drop the visibility to hidden for weak type symbols. 206 // This isn't possible if there might be unresolved references 207 // elsewhere that rely on this symbol being visible. 208 209 // This should be kept roughly in sync with setThunkVisibility 210 // in CGVTables.cpp. 211 212 // Preconditions. 213 if (GV->getLinkage() != llvm::GlobalVariable::WeakODRLinkage || 214 GV->getVisibility() != llvm::GlobalVariable::DefaultVisibility) 215 return; 216 217 // Don't override an explicit visibility attribute. 218 if (RD->hasAttr<VisibilityAttr>()) 219 return; 220 221 switch (RD->getTemplateSpecializationKind()) { 222 // We have to disable the optimization if this is an EI definition 223 // because there might be EI declarations in other shared objects. 224 case TSK_ExplicitInstantiationDefinition: 225 case TSK_ExplicitInstantiationDeclaration: 226 return; 227 228 // Every use of a non-template class's type information has to emit it. 229 case TSK_Undeclared: 230 break; 231 232 // In theory, implicit instantiations can ignore the possibility of 233 // an explicit instantiation declaration because there necessarily 234 // must be an EI definition somewhere with default visibility. In 235 // practice, it's possible to have an explicit instantiation for 236 // an arbitrary template class, and linkers aren't necessarily able 237 // to deal with mixed-visibility symbols. 238 case TSK_ExplicitSpecialization: 239 case TSK_ImplicitInstantiation: 240 if (!CodeGenOpts.HiddenWeakTemplateVTables) 241 return; 242 break; 243 } 244 245 // If there's a key function, there may be translation units 246 // that don't have the key function's definition. But ignore 247 // this if we're emitting RTTI under -fno-rtti. 248 if (!IsForRTTI || Features.RTTI) 249 if (Context.getKeyFunction(RD)) 250 return; 251 252 // Otherwise, drop the visibility to hidden. 253 GV->setVisibility(llvm::GlobalValue::HiddenVisibility); 254 } 255 256 llvm::StringRef CodeGenModule::getMangledName(GlobalDecl GD) { 257 const NamedDecl *ND = cast<NamedDecl>(GD.getDecl()); 258 259 llvm::StringRef &Str = MangledDeclNames[GD.getCanonicalDecl()]; 260 if (!Str.empty()) 261 return Str; 262 263 if (!getCXXABI().getMangleContext().shouldMangleDeclName(ND)) { 264 IdentifierInfo *II = ND->getIdentifier(); 265 assert(II && "Attempt to mangle unnamed decl."); 266 267 Str = II->getName(); 268 return Str; 269 } 270 271 llvm::SmallString<256> Buffer; 272 if (const CXXConstructorDecl *D = dyn_cast<CXXConstructorDecl>(ND)) 273 getCXXABI().getMangleContext().mangleCXXCtor(D, GD.getCtorType(), Buffer); 274 else if (const CXXDestructorDecl *D = dyn_cast<CXXDestructorDecl>(ND)) 275 getCXXABI().getMangleContext().mangleCXXDtor(D, GD.getDtorType(), Buffer); 276 else if (const BlockDecl *BD = dyn_cast<BlockDecl>(ND)) 277 getCXXABI().getMangleContext().mangleBlock(GD, BD, Buffer); 278 else 279 getCXXABI().getMangleContext().mangleName(ND, Buffer); 280 281 // Allocate space for the mangled name. 282 size_t Length = Buffer.size(); 283 char *Name = MangledNamesAllocator.Allocate<char>(Length); 284 std::copy(Buffer.begin(), Buffer.end(), Name); 285 286 Str = llvm::StringRef(Name, Length); 287 288 return Str; 289 } 290 291 void CodeGenModule::getMangledName(GlobalDecl GD, MangleBuffer &Buffer, 292 const BlockDecl *BD) { 293 getCXXABI().getMangleContext().mangleBlock(GD, BD, Buffer.getBuffer()); 294 } 295 296 llvm::GlobalValue *CodeGenModule::GetGlobalValue(llvm::StringRef Name) { 297 return getModule().getNamedValue(Name); 298 } 299 300 /// AddGlobalCtor - Add a function to the list that will be called before 301 /// main() runs. 302 void CodeGenModule::AddGlobalCtor(llvm::Function * Ctor, int Priority) { 303 // FIXME: Type coercion of void()* types. 304 GlobalCtors.push_back(std::make_pair(Ctor, Priority)); 305 } 306 307 /// AddGlobalDtor - Add a function to the list that will be called 308 /// when the module is unloaded. 309 void CodeGenModule::AddGlobalDtor(llvm::Function * Dtor, int Priority) { 310 // FIXME: Type coercion of void()* types. 311 GlobalDtors.push_back(std::make_pair(Dtor, Priority)); 312 } 313 314 void CodeGenModule::EmitCtorList(const CtorList &Fns, const char *GlobalName) { 315 // Ctor function type is void()*. 316 llvm::FunctionType* CtorFTy = 317 llvm::FunctionType::get(llvm::Type::getVoidTy(VMContext), 318 std::vector<const llvm::Type*>(), 319 false); 320 llvm::Type *CtorPFTy = llvm::PointerType::getUnqual(CtorFTy); 321 322 // Get the type of a ctor entry, { i32, void ()* }. 323 llvm::StructType* CtorStructTy = 324 llvm::StructType::get(VMContext, llvm::Type::getInt32Ty(VMContext), 325 llvm::PointerType::getUnqual(CtorFTy), NULL); 326 327 // Construct the constructor and destructor arrays. 328 std::vector<llvm::Constant*> Ctors; 329 for (CtorList::const_iterator I = Fns.begin(), E = Fns.end(); I != E; ++I) { 330 std::vector<llvm::Constant*> S; 331 S.push_back(llvm::ConstantInt::get(llvm::Type::getInt32Ty(VMContext), 332 I->second, false)); 333 S.push_back(llvm::ConstantExpr::getBitCast(I->first, CtorPFTy)); 334 Ctors.push_back(llvm::ConstantStruct::get(CtorStructTy, S)); 335 } 336 337 if (!Ctors.empty()) { 338 llvm::ArrayType *AT = llvm::ArrayType::get(CtorStructTy, Ctors.size()); 339 new llvm::GlobalVariable(TheModule, AT, false, 340 llvm::GlobalValue::AppendingLinkage, 341 llvm::ConstantArray::get(AT, Ctors), 342 GlobalName); 343 } 344 } 345 346 void CodeGenModule::EmitAnnotations() { 347 if (Annotations.empty()) 348 return; 349 350 // Create a new global variable for the ConstantStruct in the Module. 351 llvm::Constant *Array = 352 llvm::ConstantArray::get(llvm::ArrayType::get(Annotations[0]->getType(), 353 Annotations.size()), 354 Annotations); 355 llvm::GlobalValue *gv = 356 new llvm::GlobalVariable(TheModule, Array->getType(), false, 357 llvm::GlobalValue::AppendingLinkage, Array, 358 "llvm.global.annotations"); 359 gv->setSection("llvm.metadata"); 360 } 361 362 llvm::GlobalValue::LinkageTypes 363 CodeGenModule::getFunctionLinkage(const FunctionDecl *D) { 364 GVALinkage Linkage = getContext().GetGVALinkageForFunction(D); 365 366 if (Linkage == GVA_Internal) 367 return llvm::Function::InternalLinkage; 368 369 if (D->hasAttr<DLLExportAttr>()) 370 return llvm::Function::DLLExportLinkage; 371 372 if (D->hasAttr<WeakAttr>()) 373 return llvm::Function::WeakAnyLinkage; 374 375 // In C99 mode, 'inline' functions are guaranteed to have a strong 376 // definition somewhere else, so we can use available_externally linkage. 377 if (Linkage == GVA_C99Inline) 378 return llvm::Function::AvailableExternallyLinkage; 379 380 // In C++, the compiler has to emit a definition in every translation unit 381 // that references the function. We should use linkonce_odr because 382 // a) if all references in this translation unit are optimized away, we 383 // don't need to codegen it. b) if the function persists, it needs to be 384 // merged with other definitions. c) C++ has the ODR, so we know the 385 // definition is dependable. 386 if (Linkage == GVA_CXXInline || Linkage == GVA_TemplateInstantiation) 387 return llvm::Function::LinkOnceODRLinkage; 388 389 // An explicit instantiation of a template has weak linkage, since 390 // explicit instantiations can occur in multiple translation units 391 // and must all be equivalent. However, we are not allowed to 392 // throw away these explicit instantiations. 393 if (Linkage == GVA_ExplicitTemplateInstantiation) 394 return llvm::Function::WeakODRLinkage; 395 396 // Otherwise, we have strong external linkage. 397 assert(Linkage == GVA_StrongExternal); 398 return llvm::Function::ExternalLinkage; 399 } 400 401 402 /// SetFunctionDefinitionAttributes - Set attributes for a global. 403 /// 404 /// FIXME: This is currently only done for aliases and functions, but not for 405 /// variables (these details are set in EmitGlobalVarDefinition for variables). 406 void CodeGenModule::SetFunctionDefinitionAttributes(const FunctionDecl *D, 407 llvm::GlobalValue *GV) { 408 SetCommonAttributes(D, GV); 409 } 410 411 void CodeGenModule::SetLLVMFunctionAttributes(const Decl *D, 412 const CGFunctionInfo &Info, 413 llvm::Function *F) { 414 unsigned CallingConv; 415 AttributeListType AttributeList; 416 ConstructAttributeList(Info, D, AttributeList, CallingConv); 417 F->setAttributes(llvm::AttrListPtr::get(AttributeList.begin(), 418 AttributeList.size())); 419 F->setCallingConv(static_cast<llvm::CallingConv::ID>(CallingConv)); 420 } 421 422 void CodeGenModule::SetLLVMFunctionAttributesForDefinition(const Decl *D, 423 llvm::Function *F) { 424 if (!Features.Exceptions && !Features.ObjCNonFragileABI) 425 F->addFnAttr(llvm::Attribute::NoUnwind); 426 427 if (D->hasAttr<AlwaysInlineAttr>()) 428 F->addFnAttr(llvm::Attribute::AlwaysInline); 429 430 if (D->hasAttr<NakedAttr>()) 431 F->addFnAttr(llvm::Attribute::Naked); 432 433 if (D->hasAttr<NoInlineAttr>()) 434 F->addFnAttr(llvm::Attribute::NoInline); 435 436 if (Features.getStackProtectorMode() == LangOptions::SSPOn) 437 F->addFnAttr(llvm::Attribute::StackProtect); 438 else if (Features.getStackProtectorMode() == LangOptions::SSPReq) 439 F->addFnAttr(llvm::Attribute::StackProtectReq); 440 441 unsigned alignment = D->getMaxAlignment() / Context.getCharWidth(); 442 if (alignment) 443 F->setAlignment(alignment); 444 445 // C++ ABI requires 2-byte alignment for member functions. 446 if (F->getAlignment() < 2 && isa<CXXMethodDecl>(D)) 447 F->setAlignment(2); 448 } 449 450 void CodeGenModule::SetCommonAttributes(const Decl *D, 451 llvm::GlobalValue *GV) { 452 if (isa<NamedDecl>(D)) 453 setGlobalVisibility(GV, cast<NamedDecl>(D), /*ForDef*/ true); 454 else 455 GV->setVisibility(llvm::GlobalValue::DefaultVisibility); 456 457 if (D->hasAttr<UsedAttr>()) 458 AddUsedGlobal(GV); 459 460 if (const SectionAttr *SA = D->getAttr<SectionAttr>()) 461 GV->setSection(SA->getName()); 462 463 getTargetCodeGenInfo().SetTargetAttributes(D, GV, *this); 464 } 465 466 void CodeGenModule::SetInternalFunctionAttributes(const Decl *D, 467 llvm::Function *F, 468 const CGFunctionInfo &FI) { 469 SetLLVMFunctionAttributes(D, FI, F); 470 SetLLVMFunctionAttributesForDefinition(D, F); 471 472 F->setLinkage(llvm::Function::InternalLinkage); 473 474 SetCommonAttributes(D, F); 475 } 476 477 void CodeGenModule::SetFunctionAttributes(GlobalDecl GD, 478 llvm::Function *F, 479 bool IsIncompleteFunction) { 480 const FunctionDecl *FD = cast<FunctionDecl>(GD.getDecl()); 481 482 if (!IsIncompleteFunction) 483 SetLLVMFunctionAttributes(FD, getTypes().getFunctionInfo(GD), F); 484 485 // Only a few attributes are set on declarations; these may later be 486 // overridden by a definition. 487 488 if (FD->hasAttr<DLLImportAttr>()) { 489 F->setLinkage(llvm::Function::DLLImportLinkage); 490 } else if (FD->hasAttr<WeakAttr>() || 491 FD->hasAttr<WeakImportAttr>()) { 492 // "extern_weak" is overloaded in LLVM; we probably should have 493 // separate linkage types for this. 494 F->setLinkage(llvm::Function::ExternalWeakLinkage); 495 } else { 496 F->setLinkage(llvm::Function::ExternalLinkage); 497 498 NamedDecl::LinkageInfo LV = FD->getLinkageAndVisibility(); 499 if (LV.linkage() == ExternalLinkage && LV.visibilityExplicit()) { 500 F->setVisibility(GetLLVMVisibility(LV.visibility())); 501 } 502 } 503 504 if (const SectionAttr *SA = FD->getAttr<SectionAttr>()) 505 F->setSection(SA->getName()); 506 } 507 508 void CodeGenModule::AddUsedGlobal(llvm::GlobalValue *GV) { 509 assert(!GV->isDeclaration() && 510 "Only globals with definition can force usage."); 511 LLVMUsed.push_back(GV); 512 } 513 514 void CodeGenModule::EmitLLVMUsed() { 515 // Don't create llvm.used if there is no need. 516 if (LLVMUsed.empty()) 517 return; 518 519 const llvm::Type *i8PTy = llvm::Type::getInt8PtrTy(VMContext); 520 521 // Convert LLVMUsed to what ConstantArray needs. 522 std::vector<llvm::Constant*> UsedArray; 523 UsedArray.resize(LLVMUsed.size()); 524 for (unsigned i = 0, e = LLVMUsed.size(); i != e; ++i) { 525 UsedArray[i] = 526 llvm::ConstantExpr::getBitCast(cast<llvm::Constant>(&*LLVMUsed[i]), 527 i8PTy); 528 } 529 530 if (UsedArray.empty()) 531 return; 532 llvm::ArrayType *ATy = llvm::ArrayType::get(i8PTy, UsedArray.size()); 533 534 llvm::GlobalVariable *GV = 535 new llvm::GlobalVariable(getModule(), ATy, false, 536 llvm::GlobalValue::AppendingLinkage, 537 llvm::ConstantArray::get(ATy, UsedArray), 538 "llvm.used"); 539 540 GV->setSection("llvm.metadata"); 541 } 542 543 void CodeGenModule::EmitDeferred() { 544 // Emit code for any potentially referenced deferred decls. Since a 545 // previously unused static decl may become used during the generation of code 546 // for a static function, iterate until no changes are made. 547 548 while (!DeferredDeclsToEmit.empty() || !DeferredVTables.empty()) { 549 if (!DeferredVTables.empty()) { 550 const CXXRecordDecl *RD = DeferredVTables.back(); 551 DeferredVTables.pop_back(); 552 getVTables().GenerateClassData(getVTableLinkage(RD), RD); 553 continue; 554 } 555 556 GlobalDecl D = DeferredDeclsToEmit.back(); 557 DeferredDeclsToEmit.pop_back(); 558 559 // Check to see if we've already emitted this. This is necessary 560 // for a couple of reasons: first, decls can end up in the 561 // deferred-decls queue multiple times, and second, decls can end 562 // up with definitions in unusual ways (e.g. by an extern inline 563 // function acquiring a strong function redefinition). Just 564 // ignore these cases. 565 // 566 // TODO: That said, looking this up multiple times is very wasteful. 567 llvm::StringRef Name = getMangledName(D); 568 llvm::GlobalValue *CGRef = GetGlobalValue(Name); 569 assert(CGRef && "Deferred decl wasn't referenced?"); 570 571 if (!CGRef->isDeclaration()) 572 continue; 573 574 // GlobalAlias::isDeclaration() defers to the aliasee, but for our 575 // purposes an alias counts as a definition. 576 if (isa<llvm::GlobalAlias>(CGRef)) 577 continue; 578 579 // Otherwise, emit the definition and move on to the next one. 580 EmitGlobalDefinition(D); 581 } 582 } 583 584 /// EmitAnnotateAttr - Generate the llvm::ConstantStruct which contains the 585 /// annotation information for a given GlobalValue. The annotation struct is 586 /// {i8 *, i8 *, i8 *, i32}. The first field is a constant expression, the 587 /// GlobalValue being annotated. The second field is the constant string 588 /// created from the AnnotateAttr's annotation. The third field is a constant 589 /// string containing the name of the translation unit. The fourth field is 590 /// the line number in the file of the annotated value declaration. 591 /// 592 /// FIXME: this does not unique the annotation string constants, as llvm-gcc 593 /// appears to. 594 /// 595 llvm::Constant *CodeGenModule::EmitAnnotateAttr(llvm::GlobalValue *GV, 596 const AnnotateAttr *AA, 597 unsigned LineNo) { 598 llvm::Module *M = &getModule(); 599 600 // get [N x i8] constants for the annotation string, and the filename string 601 // which are the 2nd and 3rd elements of the global annotation structure. 602 const llvm::Type *SBP = llvm::Type::getInt8PtrTy(VMContext); 603 llvm::Constant *anno = llvm::ConstantArray::get(VMContext, 604 AA->getAnnotation(), true); 605 llvm::Constant *unit = llvm::ConstantArray::get(VMContext, 606 M->getModuleIdentifier(), 607 true); 608 609 // Get the two global values corresponding to the ConstantArrays we just 610 // created to hold the bytes of the strings. 611 llvm::GlobalValue *annoGV = 612 new llvm::GlobalVariable(*M, anno->getType(), false, 613 llvm::GlobalValue::PrivateLinkage, anno, 614 GV->getName()); 615 // translation unit name string, emitted into the llvm.metadata section. 616 llvm::GlobalValue *unitGV = 617 new llvm::GlobalVariable(*M, unit->getType(), false, 618 llvm::GlobalValue::PrivateLinkage, unit, 619 ".str"); 620 621 // Create the ConstantStruct for the global annotation. 622 llvm::Constant *Fields[4] = { 623 llvm::ConstantExpr::getBitCast(GV, SBP), 624 llvm::ConstantExpr::getBitCast(annoGV, SBP), 625 llvm::ConstantExpr::getBitCast(unitGV, SBP), 626 llvm::ConstantInt::get(llvm::Type::getInt32Ty(VMContext), LineNo) 627 }; 628 return llvm::ConstantStruct::get(VMContext, Fields, 4, false); 629 } 630 631 bool CodeGenModule::MayDeferGeneration(const ValueDecl *Global) { 632 // Never defer when EmitAllDecls is specified. 633 if (Features.EmitAllDecls) 634 return false; 635 636 return !getContext().DeclMustBeEmitted(Global); 637 } 638 639 llvm::Constant *CodeGenModule::GetWeakRefReference(const ValueDecl *VD) { 640 const AliasAttr *AA = VD->getAttr<AliasAttr>(); 641 assert(AA && "No alias?"); 642 643 const llvm::Type *DeclTy = getTypes().ConvertTypeForMem(VD->getType()); 644 645 // See if there is already something with the target's name in the module. 646 llvm::GlobalValue *Entry = GetGlobalValue(AA->getAliasee()); 647 648 llvm::Constant *Aliasee; 649 if (isa<llvm::FunctionType>(DeclTy)) 650 Aliasee = GetOrCreateLLVMFunction(AA->getAliasee(), DeclTy, GlobalDecl()); 651 else 652 Aliasee = GetOrCreateLLVMGlobal(AA->getAliasee(), 653 llvm::PointerType::getUnqual(DeclTy), 0); 654 if (!Entry) { 655 llvm::GlobalValue* F = cast<llvm::GlobalValue>(Aliasee); 656 F->setLinkage(llvm::Function::ExternalWeakLinkage); 657 WeakRefReferences.insert(F); 658 } 659 660 return Aliasee; 661 } 662 663 void CodeGenModule::EmitGlobal(GlobalDecl GD) { 664 const ValueDecl *Global = cast<ValueDecl>(GD.getDecl()); 665 666 // Weak references don't produce any output by themselves. 667 if (Global->hasAttr<WeakRefAttr>()) 668 return; 669 670 // If this is an alias definition (which otherwise looks like a declaration) 671 // emit it now. 672 if (Global->hasAttr<AliasAttr>()) 673 return EmitAliasDefinition(GD); 674 675 // Ignore declarations, they will be emitted on their first use. 676 if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(Global)) { 677 if (FD->getIdentifier()) { 678 llvm::StringRef Name = FD->getName(); 679 if (Name == "_Block_object_assign") { 680 BlockObjectAssignDecl = FD; 681 } else if (Name == "_Block_object_dispose") { 682 BlockObjectDisposeDecl = FD; 683 } 684 } 685 686 // Forward declarations are emitted lazily on first use. 687 if (!FD->isThisDeclarationADefinition()) 688 return; 689 } else { 690 const VarDecl *VD = cast<VarDecl>(Global); 691 assert(VD->isFileVarDecl() && "Cannot emit local var decl as global."); 692 693 if (VD->getIdentifier()) { 694 llvm::StringRef Name = VD->getName(); 695 if (Name == "_NSConcreteGlobalBlock") { 696 NSConcreteGlobalBlockDecl = VD; 697 } else if (Name == "_NSConcreteStackBlock") { 698 NSConcreteStackBlockDecl = VD; 699 } 700 } 701 702 703 if (VD->isThisDeclarationADefinition() != VarDecl::Definition) 704 return; 705 } 706 707 // Defer code generation when possible if this is a static definition, inline 708 // function etc. These we only want to emit if they are used. 709 if (!MayDeferGeneration(Global)) { 710 // Emit the definition if it can't be deferred. 711 EmitGlobalDefinition(GD); 712 return; 713 } 714 715 // If we're deferring emission of a C++ variable with an 716 // initializer, remember the order in which it appeared in the file. 717 if (getLangOptions().CPlusPlus && isa<VarDecl>(Global) && 718 cast<VarDecl>(Global)->hasInit()) { 719 DelayedCXXInitPosition[Global] = CXXGlobalInits.size(); 720 CXXGlobalInits.push_back(0); 721 } 722 723 // If the value has already been used, add it directly to the 724 // DeferredDeclsToEmit list. 725 llvm::StringRef MangledName = getMangledName(GD); 726 if (GetGlobalValue(MangledName)) 727 DeferredDeclsToEmit.push_back(GD); 728 else { 729 // Otherwise, remember that we saw a deferred decl with this name. The 730 // first use of the mangled name will cause it to move into 731 // DeferredDeclsToEmit. 732 DeferredDecls[MangledName] = GD; 733 } 734 } 735 736 void CodeGenModule::EmitGlobalDefinition(GlobalDecl GD) { 737 const ValueDecl *D = cast<ValueDecl>(GD.getDecl()); 738 739 PrettyStackTraceDecl CrashInfo(const_cast<ValueDecl *>(D), D->getLocation(), 740 Context.getSourceManager(), 741 "Generating code for declaration"); 742 743 if (const FunctionDecl *Function = dyn_cast<FunctionDecl>(D)) { 744 // At -O0, don't generate IR for functions with available_externally 745 // linkage. 746 if (CodeGenOpts.OptimizationLevel == 0 && 747 !Function->hasAttr<AlwaysInlineAttr>() && 748 getFunctionLinkage(Function) 749 == llvm::Function::AvailableExternallyLinkage) 750 return; 751 752 if (const CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(D)) { 753 if (Method->isVirtual()) 754 getVTables().EmitThunks(GD); 755 756 if (const CXXConstructorDecl *CD = dyn_cast<CXXConstructorDecl>(Method)) 757 return EmitCXXConstructor(CD, GD.getCtorType()); 758 759 if (const CXXDestructorDecl *DD = dyn_cast<CXXDestructorDecl>(Method)) 760 return EmitCXXDestructor(DD, GD.getDtorType()); 761 } 762 763 return EmitGlobalFunctionDefinition(GD); 764 } 765 766 if (const VarDecl *VD = dyn_cast<VarDecl>(D)) 767 return EmitGlobalVarDefinition(VD); 768 769 assert(0 && "Invalid argument to EmitGlobalDefinition()"); 770 } 771 772 /// GetOrCreateLLVMFunction - If the specified mangled name is not in the 773 /// module, create and return an llvm Function with the specified type. If there 774 /// is something in the module with the specified name, return it potentially 775 /// bitcasted to the right type. 776 /// 777 /// If D is non-null, it specifies a decl that correspond to this. This is used 778 /// to set the attributes on the function when it is first created. 779 llvm::Constant * 780 CodeGenModule::GetOrCreateLLVMFunction(llvm::StringRef MangledName, 781 const llvm::Type *Ty, 782 GlobalDecl D) { 783 // Lookup the entry, lazily creating it if necessary. 784 llvm::GlobalValue *Entry = GetGlobalValue(MangledName); 785 if (Entry) { 786 if (WeakRefReferences.count(Entry)) { 787 const FunctionDecl *FD = cast_or_null<FunctionDecl>(D.getDecl()); 788 if (FD && !FD->hasAttr<WeakAttr>()) 789 Entry->setLinkage(llvm::Function::ExternalLinkage); 790 791 WeakRefReferences.erase(Entry); 792 } 793 794 if (Entry->getType()->getElementType() == Ty) 795 return Entry; 796 797 // Make sure the result is of the correct type. 798 const llvm::Type *PTy = llvm::PointerType::getUnqual(Ty); 799 return llvm::ConstantExpr::getBitCast(Entry, PTy); 800 } 801 802 // This function doesn't have a complete type (for example, the return 803 // type is an incomplete struct). Use a fake type instead, and make 804 // sure not to try to set attributes. 805 bool IsIncompleteFunction = false; 806 807 const llvm::FunctionType *FTy; 808 if (isa<llvm::FunctionType>(Ty)) { 809 FTy = cast<llvm::FunctionType>(Ty); 810 } else { 811 FTy = llvm::FunctionType::get(llvm::Type::getVoidTy(VMContext), 812 std::vector<const llvm::Type*>(), false); 813 IsIncompleteFunction = true; 814 } 815 816 llvm::Function *F = llvm::Function::Create(FTy, 817 llvm::Function::ExternalLinkage, 818 MangledName, &getModule()); 819 assert(F->getName() == MangledName && "name was uniqued!"); 820 if (D.getDecl()) 821 SetFunctionAttributes(D, F, IsIncompleteFunction); 822 823 // This is the first use or definition of a mangled name. If there is a 824 // deferred decl with this name, remember that we need to emit it at the end 825 // of the file. 826 llvm::StringMap<GlobalDecl>::iterator DDI = DeferredDecls.find(MangledName); 827 if (DDI != DeferredDecls.end()) { 828 // Move the potentially referenced deferred decl to the DeferredDeclsToEmit 829 // list, and remove it from DeferredDecls (since we don't need it anymore). 830 DeferredDeclsToEmit.push_back(DDI->second); 831 DeferredDecls.erase(DDI); 832 833 // Otherwise, there are cases we have to worry about where we're 834 // using a declaration for which we must emit a definition but where 835 // we might not find a top-level definition: 836 // - member functions defined inline in their classes 837 // - friend functions defined inline in some class 838 // - special member functions with implicit definitions 839 // If we ever change our AST traversal to walk into class methods, 840 // this will be unnecessary. 841 } else if (getLangOptions().CPlusPlus && D.getDecl()) { 842 // Look for a declaration that's lexically in a record. 843 const FunctionDecl *FD = cast<FunctionDecl>(D.getDecl()); 844 do { 845 if (isa<CXXRecordDecl>(FD->getLexicalDeclContext())) { 846 if (FD->isImplicit()) { 847 assert(FD->isUsed() && "Sema didn't mark implicit function as used!"); 848 DeferredDeclsToEmit.push_back(D); 849 break; 850 } else if (FD->isThisDeclarationADefinition()) { 851 DeferredDeclsToEmit.push_back(D); 852 break; 853 } 854 } 855 FD = FD->getPreviousDeclaration(); 856 } while (FD); 857 } 858 859 // Make sure the result is of the requested type. 860 if (!IsIncompleteFunction) { 861 assert(F->getType()->getElementType() == Ty); 862 return F; 863 } 864 865 const llvm::Type *PTy = llvm::PointerType::getUnqual(Ty); 866 return llvm::ConstantExpr::getBitCast(F, PTy); 867 } 868 869 /// GetAddrOfFunction - Return the address of the given function. If Ty is 870 /// non-null, then this function will use the specified type if it has to 871 /// create it (this occurs when we see a definition of the function). 872 llvm::Constant *CodeGenModule::GetAddrOfFunction(GlobalDecl GD, 873 const llvm::Type *Ty) { 874 // If there was no specific requested type, just convert it now. 875 if (!Ty) 876 Ty = getTypes().ConvertType(cast<ValueDecl>(GD.getDecl())->getType()); 877 878 llvm::StringRef MangledName = getMangledName(GD); 879 return GetOrCreateLLVMFunction(MangledName, Ty, GD); 880 } 881 882 /// CreateRuntimeFunction - Create a new runtime function with the specified 883 /// type and name. 884 llvm::Constant * 885 CodeGenModule::CreateRuntimeFunction(const llvm::FunctionType *FTy, 886 llvm::StringRef Name) { 887 return GetOrCreateLLVMFunction(Name, FTy, GlobalDecl()); 888 } 889 890 static bool DeclIsConstantGlobal(ASTContext &Context, const VarDecl *D) { 891 if (!D->getType().isConstant(Context) && !D->getType()->isReferenceType()) 892 return false; 893 if (Context.getLangOptions().CPlusPlus && 894 Context.getBaseElementType(D->getType())->getAs<RecordType>()) { 895 // FIXME: We should do something fancier here! 896 return false; 897 } 898 return true; 899 } 900 901 /// GetOrCreateLLVMGlobal - If the specified mangled name is not in the module, 902 /// create and return an llvm GlobalVariable with the specified type. If there 903 /// is something in the module with the specified name, return it potentially 904 /// bitcasted to the right type. 905 /// 906 /// If D is non-null, it specifies a decl that correspond to this. This is used 907 /// to set the attributes on the global when it is first created. 908 llvm::Constant * 909 CodeGenModule::GetOrCreateLLVMGlobal(llvm::StringRef MangledName, 910 const llvm::PointerType *Ty, 911 const VarDecl *D) { 912 // Lookup the entry, lazily creating it if necessary. 913 llvm::GlobalValue *Entry = GetGlobalValue(MangledName); 914 if (Entry) { 915 if (WeakRefReferences.count(Entry)) { 916 if (D && !D->hasAttr<WeakAttr>()) 917 Entry->setLinkage(llvm::Function::ExternalLinkage); 918 919 WeakRefReferences.erase(Entry); 920 } 921 922 if (Entry->getType() == Ty) 923 return Entry; 924 925 // Make sure the result is of the correct type. 926 return llvm::ConstantExpr::getBitCast(Entry, Ty); 927 } 928 929 // This is the first use or definition of a mangled name. If there is a 930 // deferred decl with this name, remember that we need to emit it at the end 931 // of the file. 932 llvm::StringMap<GlobalDecl>::iterator DDI = DeferredDecls.find(MangledName); 933 if (DDI != DeferredDecls.end()) { 934 // Move the potentially referenced deferred decl to the DeferredDeclsToEmit 935 // list, and remove it from DeferredDecls (since we don't need it anymore). 936 DeferredDeclsToEmit.push_back(DDI->second); 937 DeferredDecls.erase(DDI); 938 } 939 940 llvm::GlobalVariable *GV = 941 new llvm::GlobalVariable(getModule(), Ty->getElementType(), false, 942 llvm::GlobalValue::ExternalLinkage, 943 0, MangledName, 0, 944 false, Ty->getAddressSpace()); 945 946 // Handle things which are present even on external declarations. 947 if (D) { 948 // FIXME: This code is overly simple and should be merged with other global 949 // handling. 950 GV->setConstant(DeclIsConstantGlobal(Context, D)); 951 952 // Set linkage and visibility in case we never see a definition. 953 NamedDecl::LinkageInfo LV = D->getLinkageAndVisibility(); 954 if (LV.linkage() != ExternalLinkage) { 955 GV->setLinkage(llvm::GlobalValue::InternalLinkage); 956 } else { 957 if (D->hasAttr<DLLImportAttr>()) 958 GV->setLinkage(llvm::GlobalValue::DLLImportLinkage); 959 else if (D->hasAttr<WeakAttr>() || D->hasAttr<WeakImportAttr>()) 960 GV->setLinkage(llvm::GlobalValue::ExternalWeakLinkage); 961 962 // Set visibility on a declaration only if it's explicit. 963 if (LV.visibilityExplicit()) 964 GV->setVisibility(GetLLVMVisibility(LV.visibility())); 965 } 966 967 GV->setThreadLocal(D->isThreadSpecified()); 968 } 969 970 return GV; 971 } 972 973 974 /// GetAddrOfGlobalVar - Return the llvm::Constant for the address of the 975 /// given global variable. If Ty is non-null and if the global doesn't exist, 976 /// then it will be greated with the specified type instead of whatever the 977 /// normal requested type would be. 978 llvm::Constant *CodeGenModule::GetAddrOfGlobalVar(const VarDecl *D, 979 const llvm::Type *Ty) { 980 assert(D->hasGlobalStorage() && "Not a global variable"); 981 QualType ASTTy = D->getType(); 982 if (Ty == 0) 983 Ty = getTypes().ConvertTypeForMem(ASTTy); 984 985 const llvm::PointerType *PTy = 986 llvm::PointerType::get(Ty, ASTTy.getAddressSpace()); 987 988 llvm::StringRef MangledName = getMangledName(D); 989 return GetOrCreateLLVMGlobal(MangledName, PTy, D); 990 } 991 992 /// CreateRuntimeVariable - Create a new runtime global variable with the 993 /// specified type and name. 994 llvm::Constant * 995 CodeGenModule::CreateRuntimeVariable(const llvm::Type *Ty, 996 llvm::StringRef Name) { 997 return GetOrCreateLLVMGlobal(Name, llvm::PointerType::getUnqual(Ty), 0); 998 } 999 1000 void CodeGenModule::EmitTentativeDefinition(const VarDecl *D) { 1001 assert(!D->getInit() && "Cannot emit definite definitions here!"); 1002 1003 if (MayDeferGeneration(D)) { 1004 // If we have not seen a reference to this variable yet, place it 1005 // into the deferred declarations table to be emitted if needed 1006 // later. 1007 llvm::StringRef MangledName = getMangledName(D); 1008 if (!GetGlobalValue(MangledName)) { 1009 DeferredDecls[MangledName] = D; 1010 return; 1011 } 1012 } 1013 1014 // The tentative definition is the only definition. 1015 EmitGlobalVarDefinition(D); 1016 } 1017 1018 void CodeGenModule::EmitVTable(CXXRecordDecl *Class, bool DefinitionRequired) { 1019 if (DefinitionRequired) 1020 getVTables().GenerateClassData(getVTableLinkage(Class), Class); 1021 } 1022 1023 llvm::GlobalVariable::LinkageTypes 1024 CodeGenModule::getVTableLinkage(const CXXRecordDecl *RD) { 1025 if (RD->isInAnonymousNamespace() || !RD->hasLinkage()) 1026 return llvm::GlobalVariable::InternalLinkage; 1027 1028 if (const CXXMethodDecl *KeyFunction 1029 = RD->getASTContext().getKeyFunction(RD)) { 1030 // If this class has a key function, use that to determine the linkage of 1031 // the vtable. 1032 const FunctionDecl *Def = 0; 1033 if (KeyFunction->hasBody(Def)) 1034 KeyFunction = cast<CXXMethodDecl>(Def); 1035 1036 switch (KeyFunction->getTemplateSpecializationKind()) { 1037 case TSK_Undeclared: 1038 case TSK_ExplicitSpecialization: 1039 if (KeyFunction->isInlined()) 1040 return llvm::GlobalVariable::WeakODRLinkage; 1041 1042 return llvm::GlobalVariable::ExternalLinkage; 1043 1044 case TSK_ImplicitInstantiation: 1045 case TSK_ExplicitInstantiationDefinition: 1046 return llvm::GlobalVariable::WeakODRLinkage; 1047 1048 case TSK_ExplicitInstantiationDeclaration: 1049 // FIXME: Use available_externally linkage. However, this currently 1050 // breaks LLVM's build due to undefined symbols. 1051 // return llvm::GlobalVariable::AvailableExternallyLinkage; 1052 return llvm::GlobalVariable::WeakODRLinkage; 1053 } 1054 } 1055 1056 switch (RD->getTemplateSpecializationKind()) { 1057 case TSK_Undeclared: 1058 case TSK_ExplicitSpecialization: 1059 case TSK_ImplicitInstantiation: 1060 case TSK_ExplicitInstantiationDefinition: 1061 return llvm::GlobalVariable::WeakODRLinkage; 1062 1063 case TSK_ExplicitInstantiationDeclaration: 1064 // FIXME: Use available_externally linkage. However, this currently 1065 // breaks LLVM's build due to undefined symbols. 1066 // return llvm::GlobalVariable::AvailableExternallyLinkage; 1067 return llvm::GlobalVariable::WeakODRLinkage; 1068 } 1069 1070 // Silence GCC warning. 1071 return llvm::GlobalVariable::WeakODRLinkage; 1072 } 1073 1074 CharUnits CodeGenModule::GetTargetTypeStoreSize(const llvm::Type *Ty) const { 1075 return CharUnits::fromQuantity( 1076 TheTargetData.getTypeStoreSizeInBits(Ty) / Context.getCharWidth()); 1077 } 1078 1079 void CodeGenModule::EmitGlobalVarDefinition(const VarDecl *D) { 1080 llvm::Constant *Init = 0; 1081 QualType ASTTy = D->getType(); 1082 bool NonConstInit = false; 1083 1084 const Expr *InitExpr = D->getAnyInitializer(); 1085 1086 if (!InitExpr) { 1087 // This is a tentative definition; tentative definitions are 1088 // implicitly initialized with { 0 }. 1089 // 1090 // Note that tentative definitions are only emitted at the end of 1091 // a translation unit, so they should never have incomplete 1092 // type. In addition, EmitTentativeDefinition makes sure that we 1093 // never attempt to emit a tentative definition if a real one 1094 // exists. A use may still exists, however, so we still may need 1095 // to do a RAUW. 1096 assert(!ASTTy->isIncompleteType() && "Unexpected incomplete type"); 1097 Init = EmitNullConstant(D->getType()); 1098 } else { 1099 Init = EmitConstantExpr(InitExpr, D->getType()); 1100 if (!Init) { 1101 QualType T = InitExpr->getType(); 1102 if (D->getType()->isReferenceType()) 1103 T = D->getType(); 1104 1105 if (getLangOptions().CPlusPlus) { 1106 Init = EmitNullConstant(T); 1107 NonConstInit = true; 1108 } else { 1109 ErrorUnsupported(D, "static initializer"); 1110 Init = llvm::UndefValue::get(getTypes().ConvertType(T)); 1111 } 1112 } else { 1113 // We don't need an initializer, so remove the entry for the delayed 1114 // initializer position (just in case this entry was delayed). 1115 if (getLangOptions().CPlusPlus) 1116 DelayedCXXInitPosition.erase(D); 1117 } 1118 } 1119 1120 const llvm::Type* InitType = Init->getType(); 1121 llvm::Constant *Entry = GetAddrOfGlobalVar(D, InitType); 1122 1123 // Strip off a bitcast if we got one back. 1124 if (llvm::ConstantExpr *CE = dyn_cast<llvm::ConstantExpr>(Entry)) { 1125 assert(CE->getOpcode() == llvm::Instruction::BitCast || 1126 // all zero index gep. 1127 CE->getOpcode() == llvm::Instruction::GetElementPtr); 1128 Entry = CE->getOperand(0); 1129 } 1130 1131 // Entry is now either a Function or GlobalVariable. 1132 llvm::GlobalVariable *GV = dyn_cast<llvm::GlobalVariable>(Entry); 1133 1134 // We have a definition after a declaration with the wrong type. 1135 // We must make a new GlobalVariable* and update everything that used OldGV 1136 // (a declaration or tentative definition) with the new GlobalVariable* 1137 // (which will be a definition). 1138 // 1139 // This happens if there is a prototype for a global (e.g. 1140 // "extern int x[];") and then a definition of a different type (e.g. 1141 // "int x[10];"). This also happens when an initializer has a different type 1142 // from the type of the global (this happens with unions). 1143 if (GV == 0 || 1144 GV->getType()->getElementType() != InitType || 1145 GV->getType()->getAddressSpace() != ASTTy.getAddressSpace()) { 1146 1147 // Move the old entry aside so that we'll create a new one. 1148 Entry->setName(llvm::StringRef()); 1149 1150 // Make a new global with the correct type, this is now guaranteed to work. 1151 GV = cast<llvm::GlobalVariable>(GetAddrOfGlobalVar(D, InitType)); 1152 1153 // Replace all uses of the old global with the new global 1154 llvm::Constant *NewPtrForOldDecl = 1155 llvm::ConstantExpr::getBitCast(GV, Entry->getType()); 1156 Entry->replaceAllUsesWith(NewPtrForOldDecl); 1157 1158 // Erase the old global, since it is no longer used. 1159 cast<llvm::GlobalValue>(Entry)->eraseFromParent(); 1160 } 1161 1162 if (const AnnotateAttr *AA = D->getAttr<AnnotateAttr>()) { 1163 SourceManager &SM = Context.getSourceManager(); 1164 AddAnnotation(EmitAnnotateAttr(GV, AA, 1165 SM.getInstantiationLineNumber(D->getLocation()))); 1166 } 1167 1168 GV->setInitializer(Init); 1169 1170 // If it is safe to mark the global 'constant', do so now. 1171 GV->setConstant(false); 1172 if (!NonConstInit && DeclIsConstantGlobal(Context, D)) 1173 GV->setConstant(true); 1174 1175 GV->setAlignment(getContext().getDeclAlign(D).getQuantity()); 1176 1177 // Set the llvm linkage type as appropriate. 1178 llvm::GlobalValue::LinkageTypes Linkage = 1179 GetLLVMLinkageVarDefinition(D, GV); 1180 GV->setLinkage(Linkage); 1181 if (Linkage == llvm::GlobalVariable::CommonLinkage) 1182 // common vars aren't constant even if declared const. 1183 GV->setConstant(false); 1184 1185 SetCommonAttributes(D, GV); 1186 1187 // Emit the initializer function if necessary. 1188 if (NonConstInit) 1189 EmitCXXGlobalVarDeclInitFunc(D, GV); 1190 1191 // Emit global variable debug information. 1192 if (CGDebugInfo *DI = getDebugInfo()) { 1193 DI->setLocation(D->getLocation()); 1194 DI->EmitGlobalVariable(GV, D); 1195 } 1196 } 1197 1198 llvm::GlobalValue::LinkageTypes 1199 CodeGenModule::GetLLVMLinkageVarDefinition(const VarDecl *D, 1200 llvm::GlobalVariable *GV) { 1201 GVALinkage Linkage = getContext().GetGVALinkageForVariable(D); 1202 if (Linkage == GVA_Internal) 1203 return llvm::Function::InternalLinkage; 1204 else if (D->hasAttr<DLLImportAttr>()) 1205 return llvm::Function::DLLImportLinkage; 1206 else if (D->hasAttr<DLLExportAttr>()) 1207 return llvm::Function::DLLExportLinkage; 1208 else if (D->hasAttr<WeakAttr>()) { 1209 if (GV->isConstant()) 1210 return llvm::GlobalVariable::WeakODRLinkage; 1211 else 1212 return llvm::GlobalVariable::WeakAnyLinkage; 1213 } else if (Linkage == GVA_TemplateInstantiation || 1214 Linkage == GVA_ExplicitTemplateInstantiation) 1215 // FIXME: It seems like we can provide more specific linkage here 1216 // (LinkOnceODR, WeakODR). 1217 return llvm::GlobalVariable::WeakAnyLinkage; 1218 else if (!getLangOptions().CPlusPlus && 1219 ((!CodeGenOpts.NoCommon && !D->getAttr<NoCommonAttr>()) || 1220 D->getAttr<CommonAttr>()) && 1221 !D->hasExternalStorage() && !D->getInit() && 1222 !D->getAttr<SectionAttr>() && !D->isThreadSpecified()) { 1223 // Thread local vars aren't considered common linkage. 1224 return llvm::GlobalVariable::CommonLinkage; 1225 } 1226 return llvm::GlobalVariable::ExternalLinkage; 1227 } 1228 1229 /// ReplaceUsesOfNonProtoTypeWithRealFunction - This function is called when we 1230 /// implement a function with no prototype, e.g. "int foo() {}". If there are 1231 /// existing call uses of the old function in the module, this adjusts them to 1232 /// call the new function directly. 1233 /// 1234 /// This is not just a cleanup: the always_inline pass requires direct calls to 1235 /// functions to be able to inline them. If there is a bitcast in the way, it 1236 /// won't inline them. Instcombine normally deletes these calls, but it isn't 1237 /// run at -O0. 1238 static void ReplaceUsesOfNonProtoTypeWithRealFunction(llvm::GlobalValue *Old, 1239 llvm::Function *NewFn) { 1240 // If we're redefining a global as a function, don't transform it. 1241 llvm::Function *OldFn = dyn_cast<llvm::Function>(Old); 1242 if (OldFn == 0) return; 1243 1244 const llvm::Type *NewRetTy = NewFn->getReturnType(); 1245 llvm::SmallVector<llvm::Value*, 4> ArgList; 1246 1247 for (llvm::Value::use_iterator UI = OldFn->use_begin(), E = OldFn->use_end(); 1248 UI != E; ) { 1249 // TODO: Do invokes ever occur in C code? If so, we should handle them too. 1250 llvm::Value::use_iterator I = UI++; // Increment before the CI is erased. 1251 llvm::CallInst *CI = dyn_cast<llvm::CallInst>(*I); 1252 if (!CI) continue; // FIXME: when we allow Invoke, just do CallSite CS(*I) 1253 llvm::CallSite CS(CI); 1254 if (!CI || !CS.isCallee(I)) continue; 1255 1256 // If the return types don't match exactly, and if the call isn't dead, then 1257 // we can't transform this call. 1258 if (CI->getType() != NewRetTy && !CI->use_empty()) 1259 continue; 1260 1261 // If the function was passed too few arguments, don't transform. If extra 1262 // arguments were passed, we silently drop them. If any of the types 1263 // mismatch, we don't transform. 1264 unsigned ArgNo = 0; 1265 bool DontTransform = false; 1266 for (llvm::Function::arg_iterator AI = NewFn->arg_begin(), 1267 E = NewFn->arg_end(); AI != E; ++AI, ++ArgNo) { 1268 if (CS.arg_size() == ArgNo || 1269 CS.getArgument(ArgNo)->getType() != AI->getType()) { 1270 DontTransform = true; 1271 break; 1272 } 1273 } 1274 if (DontTransform) 1275 continue; 1276 1277 // Okay, we can transform this. Create the new call instruction and copy 1278 // over the required information. 1279 ArgList.append(CS.arg_begin(), CS.arg_begin() + ArgNo); 1280 llvm::CallInst *NewCall = llvm::CallInst::Create(NewFn, ArgList.begin(), 1281 ArgList.end(), "", CI); 1282 ArgList.clear(); 1283 if (!NewCall->getType()->isVoidTy()) 1284 NewCall->takeName(CI); 1285 NewCall->setAttributes(CI->getAttributes()); 1286 NewCall->setCallingConv(CI->getCallingConv()); 1287 1288 // Finally, remove the old call, replacing any uses with the new one. 1289 if (!CI->use_empty()) 1290 CI->replaceAllUsesWith(NewCall); 1291 1292 // Copy debug location attached to CI. 1293 if (!CI->getDebugLoc().isUnknown()) 1294 NewCall->setDebugLoc(CI->getDebugLoc()); 1295 CI->eraseFromParent(); 1296 } 1297 } 1298 1299 1300 void CodeGenModule::EmitGlobalFunctionDefinition(GlobalDecl GD) { 1301 const FunctionDecl *D = cast<FunctionDecl>(GD.getDecl()); 1302 const llvm::FunctionType *Ty = getTypes().GetFunctionType(GD); 1303 getCXXABI().getMangleContext().mangleInitDiscriminator(); 1304 // Get or create the prototype for the function. 1305 llvm::Constant *Entry = GetAddrOfFunction(GD, Ty); 1306 1307 // Strip off a bitcast if we got one back. 1308 if (llvm::ConstantExpr *CE = dyn_cast<llvm::ConstantExpr>(Entry)) { 1309 assert(CE->getOpcode() == llvm::Instruction::BitCast); 1310 Entry = CE->getOperand(0); 1311 } 1312 1313 1314 if (cast<llvm::GlobalValue>(Entry)->getType()->getElementType() != Ty) { 1315 llvm::GlobalValue *OldFn = cast<llvm::GlobalValue>(Entry); 1316 1317 // If the types mismatch then we have to rewrite the definition. 1318 assert(OldFn->isDeclaration() && 1319 "Shouldn't replace non-declaration"); 1320 1321 // F is the Function* for the one with the wrong type, we must make a new 1322 // Function* and update everything that used F (a declaration) with the new 1323 // Function* (which will be a definition). 1324 // 1325 // This happens if there is a prototype for a function 1326 // (e.g. "int f()") and then a definition of a different type 1327 // (e.g. "int f(int x)"). Move the old function aside so that it 1328 // doesn't interfere with GetAddrOfFunction. 1329 OldFn->setName(llvm::StringRef()); 1330 llvm::Function *NewFn = cast<llvm::Function>(GetAddrOfFunction(GD, Ty)); 1331 1332 // If this is an implementation of a function without a prototype, try to 1333 // replace any existing uses of the function (which may be calls) with uses 1334 // of the new function 1335 if (D->getType()->isFunctionNoProtoType()) { 1336 ReplaceUsesOfNonProtoTypeWithRealFunction(OldFn, NewFn); 1337 OldFn->removeDeadConstantUsers(); 1338 } 1339 1340 // Replace uses of F with the Function we will endow with a body. 1341 if (!Entry->use_empty()) { 1342 llvm::Constant *NewPtrForOldDecl = 1343 llvm::ConstantExpr::getBitCast(NewFn, Entry->getType()); 1344 Entry->replaceAllUsesWith(NewPtrForOldDecl); 1345 } 1346 1347 // Ok, delete the old function now, which is dead. 1348 OldFn->eraseFromParent(); 1349 1350 Entry = NewFn; 1351 } 1352 1353 // We need to set linkage and visibility on the function before 1354 // generating code for it because various parts of IR generation 1355 // want to propagate this information down (e.g. to local static 1356 // declarations). 1357 llvm::Function *Fn = cast<llvm::Function>(Entry); 1358 setFunctionLinkage(D, Fn); 1359 1360 // FIXME: this is redundant with part of SetFunctionDefinitionAttributes 1361 setGlobalVisibility(Fn, D, /*ForDef*/ true); 1362 1363 CodeGenFunction(*this).GenerateCode(D, Fn); 1364 1365 SetFunctionDefinitionAttributes(D, Fn); 1366 SetLLVMFunctionAttributesForDefinition(D, Fn); 1367 1368 if (const ConstructorAttr *CA = D->getAttr<ConstructorAttr>()) 1369 AddGlobalCtor(Fn, CA->getPriority()); 1370 if (const DestructorAttr *DA = D->getAttr<DestructorAttr>()) 1371 AddGlobalDtor(Fn, DA->getPriority()); 1372 } 1373 1374 void CodeGenModule::EmitAliasDefinition(GlobalDecl GD) { 1375 const ValueDecl *D = cast<ValueDecl>(GD.getDecl()); 1376 const AliasAttr *AA = D->getAttr<AliasAttr>(); 1377 assert(AA && "Not an alias?"); 1378 1379 llvm::StringRef MangledName = getMangledName(GD); 1380 1381 // If there is a definition in the module, then it wins over the alias. 1382 // This is dubious, but allow it to be safe. Just ignore the alias. 1383 llvm::GlobalValue *Entry = GetGlobalValue(MangledName); 1384 if (Entry && !Entry->isDeclaration()) 1385 return; 1386 1387 const llvm::Type *DeclTy = getTypes().ConvertTypeForMem(D->getType()); 1388 1389 // Create a reference to the named value. This ensures that it is emitted 1390 // if a deferred decl. 1391 llvm::Constant *Aliasee; 1392 if (isa<llvm::FunctionType>(DeclTy)) 1393 Aliasee = GetOrCreateLLVMFunction(AA->getAliasee(), DeclTy, GlobalDecl()); 1394 else 1395 Aliasee = GetOrCreateLLVMGlobal(AA->getAliasee(), 1396 llvm::PointerType::getUnqual(DeclTy), 0); 1397 1398 // Create the new alias itself, but don't set a name yet. 1399 llvm::GlobalValue *GA = 1400 new llvm::GlobalAlias(Aliasee->getType(), 1401 llvm::Function::ExternalLinkage, 1402 "", Aliasee, &getModule()); 1403 1404 if (Entry) { 1405 assert(Entry->isDeclaration()); 1406 1407 // If there is a declaration in the module, then we had an extern followed 1408 // by the alias, as in: 1409 // extern int test6(); 1410 // ... 1411 // int test6() __attribute__((alias("test7"))); 1412 // 1413 // Remove it and replace uses of it with the alias. 1414 GA->takeName(Entry); 1415 1416 Entry->replaceAllUsesWith(llvm::ConstantExpr::getBitCast(GA, 1417 Entry->getType())); 1418 Entry->eraseFromParent(); 1419 } else { 1420 GA->setName(MangledName); 1421 } 1422 1423 // Set attributes which are particular to an alias; this is a 1424 // specialization of the attributes which may be set on a global 1425 // variable/function. 1426 if (D->hasAttr<DLLExportAttr>()) { 1427 if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) { 1428 // The dllexport attribute is ignored for undefined symbols. 1429 if (FD->hasBody()) 1430 GA->setLinkage(llvm::Function::DLLExportLinkage); 1431 } else { 1432 GA->setLinkage(llvm::Function::DLLExportLinkage); 1433 } 1434 } else if (D->hasAttr<WeakAttr>() || 1435 D->hasAttr<WeakRefAttr>() || 1436 D->hasAttr<WeakImportAttr>()) { 1437 GA->setLinkage(llvm::Function::WeakAnyLinkage); 1438 } 1439 1440 SetCommonAttributes(D, GA); 1441 } 1442 1443 /// getBuiltinLibFunction - Given a builtin id for a function like 1444 /// "__builtin_fabsf", return a Function* for "fabsf". 1445 llvm::Value *CodeGenModule::getBuiltinLibFunction(const FunctionDecl *FD, 1446 unsigned BuiltinID) { 1447 assert((Context.BuiltinInfo.isLibFunction(BuiltinID) || 1448 Context.BuiltinInfo.isPredefinedLibFunction(BuiltinID)) && 1449 "isn't a lib fn"); 1450 1451 // Get the name, skip over the __builtin_ prefix (if necessary). 1452 const char *Name = Context.BuiltinInfo.GetName(BuiltinID); 1453 if (Context.BuiltinInfo.isLibFunction(BuiltinID)) 1454 Name += 10; 1455 1456 const llvm::FunctionType *Ty = 1457 cast<llvm::FunctionType>(getTypes().ConvertType(FD->getType())); 1458 1459 return GetOrCreateLLVMFunction(Name, Ty, GlobalDecl(FD)); 1460 } 1461 1462 llvm::Function *CodeGenModule::getIntrinsic(unsigned IID,const llvm::Type **Tys, 1463 unsigned NumTys) { 1464 return llvm::Intrinsic::getDeclaration(&getModule(), 1465 (llvm::Intrinsic::ID)IID, Tys, NumTys); 1466 } 1467 1468 static llvm::StringMapEntry<llvm::Constant*> & 1469 GetConstantCFStringEntry(llvm::StringMap<llvm::Constant*> &Map, 1470 const StringLiteral *Literal, 1471 bool TargetIsLSB, 1472 bool &IsUTF16, 1473 unsigned &StringLength) { 1474 llvm::StringRef String = Literal->getString(); 1475 unsigned NumBytes = String.size(); 1476 1477 // Check for simple case. 1478 if (!Literal->containsNonAsciiOrNull()) { 1479 StringLength = NumBytes; 1480 return Map.GetOrCreateValue(String); 1481 } 1482 1483 // Otherwise, convert the UTF8 literals into a byte string. 1484 llvm::SmallVector<UTF16, 128> ToBuf(NumBytes); 1485 const UTF8 *FromPtr = (UTF8 *)String.data(); 1486 UTF16 *ToPtr = &ToBuf[0]; 1487 1488 (void)ConvertUTF8toUTF16(&FromPtr, FromPtr + NumBytes, 1489 &ToPtr, ToPtr + NumBytes, 1490 strictConversion); 1491 1492 // ConvertUTF8toUTF16 returns the length in ToPtr. 1493 StringLength = ToPtr - &ToBuf[0]; 1494 1495 // Render the UTF-16 string into a byte array and convert to the target byte 1496 // order. 1497 // 1498 // FIXME: This isn't something we should need to do here. 1499 llvm::SmallString<128> AsBytes; 1500 AsBytes.reserve(StringLength * 2); 1501 for (unsigned i = 0; i != StringLength; ++i) { 1502 unsigned short Val = ToBuf[i]; 1503 if (TargetIsLSB) { 1504 AsBytes.push_back(Val & 0xFF); 1505 AsBytes.push_back(Val >> 8); 1506 } else { 1507 AsBytes.push_back(Val >> 8); 1508 AsBytes.push_back(Val & 0xFF); 1509 } 1510 } 1511 // Append one extra null character, the second is automatically added by our 1512 // caller. 1513 AsBytes.push_back(0); 1514 1515 IsUTF16 = true; 1516 return Map.GetOrCreateValue(llvm::StringRef(AsBytes.data(), AsBytes.size())); 1517 } 1518 1519 llvm::Constant * 1520 CodeGenModule::GetAddrOfConstantCFString(const StringLiteral *Literal) { 1521 unsigned StringLength = 0; 1522 bool isUTF16 = false; 1523 llvm::StringMapEntry<llvm::Constant*> &Entry = 1524 GetConstantCFStringEntry(CFConstantStringMap, Literal, 1525 getTargetData().isLittleEndian(), 1526 isUTF16, StringLength); 1527 1528 if (llvm::Constant *C = Entry.getValue()) 1529 return C; 1530 1531 llvm::Constant *Zero = 1532 llvm::Constant::getNullValue(llvm::Type::getInt32Ty(VMContext)); 1533 llvm::Constant *Zeros[] = { Zero, Zero }; 1534 1535 // If we don't already have it, get __CFConstantStringClassReference. 1536 if (!CFConstantStringClassRef) { 1537 const llvm::Type *Ty = getTypes().ConvertType(getContext().IntTy); 1538 Ty = llvm::ArrayType::get(Ty, 0); 1539 llvm::Constant *GV = CreateRuntimeVariable(Ty, 1540 "__CFConstantStringClassReference"); 1541 // Decay array -> ptr 1542 CFConstantStringClassRef = 1543 llvm::ConstantExpr::getGetElementPtr(GV, Zeros, 2); 1544 } 1545 1546 QualType CFTy = getContext().getCFConstantStringType(); 1547 1548 const llvm::StructType *STy = 1549 cast<llvm::StructType>(getTypes().ConvertType(CFTy)); 1550 1551 std::vector<llvm::Constant*> Fields(4); 1552 1553 // Class pointer. 1554 Fields[0] = CFConstantStringClassRef; 1555 1556 // Flags. 1557 const llvm::Type *Ty = getTypes().ConvertType(getContext().UnsignedIntTy); 1558 Fields[1] = isUTF16 ? llvm::ConstantInt::get(Ty, 0x07d0) : 1559 llvm::ConstantInt::get(Ty, 0x07C8); 1560 1561 // String pointer. 1562 llvm::Constant *C = llvm::ConstantArray::get(VMContext, Entry.getKey().str()); 1563 1564 llvm::GlobalValue::LinkageTypes Linkage; 1565 bool isConstant; 1566 if (isUTF16) { 1567 // FIXME: why do utf strings get "_" labels instead of "L" labels? 1568 Linkage = llvm::GlobalValue::InternalLinkage; 1569 // Note: -fwritable-strings doesn't make unicode CFStrings writable, but 1570 // does make plain ascii ones writable. 1571 isConstant = true; 1572 } else { 1573 Linkage = llvm::GlobalValue::PrivateLinkage; 1574 isConstant = !Features.WritableStrings; 1575 } 1576 1577 llvm::GlobalVariable *GV = 1578 new llvm::GlobalVariable(getModule(), C->getType(), isConstant, Linkage, C, 1579 ".str"); 1580 if (isUTF16) { 1581 CharUnits Align = getContext().getTypeAlignInChars(getContext().ShortTy); 1582 GV->setAlignment(Align.getQuantity()); 1583 } 1584 Fields[2] = llvm::ConstantExpr::getGetElementPtr(GV, Zeros, 2); 1585 1586 // String length. 1587 Ty = getTypes().ConvertType(getContext().LongTy); 1588 Fields[3] = llvm::ConstantInt::get(Ty, StringLength); 1589 1590 // The struct. 1591 C = llvm::ConstantStruct::get(STy, Fields); 1592 GV = new llvm::GlobalVariable(getModule(), C->getType(), true, 1593 llvm::GlobalVariable::PrivateLinkage, C, 1594 "_unnamed_cfstring_"); 1595 if (const char *Sect = getContext().Target.getCFStringSection()) 1596 GV->setSection(Sect); 1597 Entry.setValue(GV); 1598 1599 return GV; 1600 } 1601 1602 llvm::Constant * 1603 CodeGenModule::GetAddrOfConstantString(const StringLiteral *Literal) { 1604 unsigned StringLength = 0; 1605 bool isUTF16 = false; 1606 llvm::StringMapEntry<llvm::Constant*> &Entry = 1607 GetConstantCFStringEntry(CFConstantStringMap, Literal, 1608 getTargetData().isLittleEndian(), 1609 isUTF16, StringLength); 1610 1611 if (llvm::Constant *C = Entry.getValue()) 1612 return C; 1613 1614 llvm::Constant *Zero = 1615 llvm::Constant::getNullValue(llvm::Type::getInt32Ty(VMContext)); 1616 llvm::Constant *Zeros[] = { Zero, Zero }; 1617 1618 // If we don't already have it, get _NSConstantStringClassReference. 1619 if (!ConstantStringClassRef) { 1620 std::string StringClass(getLangOptions().ObjCConstantStringClass); 1621 const llvm::Type *Ty = getTypes().ConvertType(getContext().IntTy); 1622 Ty = llvm::ArrayType::get(Ty, 0); 1623 llvm::Constant *GV; 1624 if (StringClass.empty()) 1625 GV = CreateRuntimeVariable(Ty, 1626 Features.ObjCNonFragileABI ? 1627 "OBJC_CLASS_$_NSConstantString" : 1628 "_NSConstantStringClassReference"); 1629 else { 1630 std::string str; 1631 if (Features.ObjCNonFragileABI) 1632 str = "OBJC_CLASS_$_" + StringClass; 1633 else 1634 str = "_" + StringClass + "ClassReference"; 1635 GV = CreateRuntimeVariable(Ty, str); 1636 } 1637 // Decay array -> ptr 1638 ConstantStringClassRef = 1639 llvm::ConstantExpr::getGetElementPtr(GV, Zeros, 2); 1640 } 1641 1642 QualType NSTy = getContext().getNSConstantStringType(); 1643 1644 const llvm::StructType *STy = 1645 cast<llvm::StructType>(getTypes().ConvertType(NSTy)); 1646 1647 std::vector<llvm::Constant*> Fields(3); 1648 1649 // Class pointer. 1650 Fields[0] = ConstantStringClassRef; 1651 1652 // String pointer. 1653 llvm::Constant *C = llvm::ConstantArray::get(VMContext, Entry.getKey().str()); 1654 1655 llvm::GlobalValue::LinkageTypes Linkage; 1656 bool isConstant; 1657 if (isUTF16) { 1658 // FIXME: why do utf strings get "_" labels instead of "L" labels? 1659 Linkage = llvm::GlobalValue::InternalLinkage; 1660 // Note: -fwritable-strings doesn't make unicode NSStrings writable, but 1661 // does make plain ascii ones writable. 1662 isConstant = true; 1663 } else { 1664 Linkage = llvm::GlobalValue::PrivateLinkage; 1665 isConstant = !Features.WritableStrings; 1666 } 1667 1668 llvm::GlobalVariable *GV = 1669 new llvm::GlobalVariable(getModule(), C->getType(), isConstant, Linkage, C, 1670 ".str"); 1671 if (isUTF16) { 1672 CharUnits Align = getContext().getTypeAlignInChars(getContext().ShortTy); 1673 GV->setAlignment(Align.getQuantity()); 1674 } 1675 Fields[1] = llvm::ConstantExpr::getGetElementPtr(GV, Zeros, 2); 1676 1677 // String length. 1678 const llvm::Type *Ty = getTypes().ConvertType(getContext().UnsignedIntTy); 1679 Fields[2] = llvm::ConstantInt::get(Ty, StringLength); 1680 1681 // The struct. 1682 C = llvm::ConstantStruct::get(STy, Fields); 1683 GV = new llvm::GlobalVariable(getModule(), C->getType(), true, 1684 llvm::GlobalVariable::PrivateLinkage, C, 1685 "_unnamed_nsstring_"); 1686 // FIXME. Fix section. 1687 if (const char *Sect = 1688 Features.ObjCNonFragileABI 1689 ? getContext().Target.getNSStringNonFragileABISection() 1690 : getContext().Target.getNSStringSection()) 1691 GV->setSection(Sect); 1692 Entry.setValue(GV); 1693 1694 return GV; 1695 } 1696 1697 /// GetStringForStringLiteral - Return the appropriate bytes for a 1698 /// string literal, properly padded to match the literal type. 1699 std::string CodeGenModule::GetStringForStringLiteral(const StringLiteral *E) { 1700 const ConstantArrayType *CAT = 1701 getContext().getAsConstantArrayType(E->getType()); 1702 assert(CAT && "String isn't pointer or array!"); 1703 1704 // Resize the string to the right size. 1705 uint64_t RealLen = CAT->getSize().getZExtValue(); 1706 1707 if (E->isWide()) 1708 RealLen *= getContext().Target.getWCharWidth()/8; 1709 1710 std::string Str = E->getString().str(); 1711 Str.resize(RealLen, '\0'); 1712 1713 return Str; 1714 } 1715 1716 /// GetAddrOfConstantStringFromLiteral - Return a pointer to a 1717 /// constant array for the given string literal. 1718 llvm::Constant * 1719 CodeGenModule::GetAddrOfConstantStringFromLiteral(const StringLiteral *S) { 1720 // FIXME: This can be more efficient. 1721 // FIXME: We shouldn't need to bitcast the constant in the wide string case. 1722 llvm::Constant *C = GetAddrOfConstantString(GetStringForStringLiteral(S)); 1723 if (S->isWide()) { 1724 llvm::Type *DestTy = 1725 llvm::PointerType::getUnqual(getTypes().ConvertType(S->getType())); 1726 C = llvm::ConstantExpr::getBitCast(C, DestTy); 1727 } 1728 return C; 1729 } 1730 1731 /// GetAddrOfConstantStringFromObjCEncode - Return a pointer to a constant 1732 /// array for the given ObjCEncodeExpr node. 1733 llvm::Constant * 1734 CodeGenModule::GetAddrOfConstantStringFromObjCEncode(const ObjCEncodeExpr *E) { 1735 std::string Str; 1736 getContext().getObjCEncodingForType(E->getEncodedType(), Str); 1737 1738 return GetAddrOfConstantCString(Str); 1739 } 1740 1741 1742 /// GenerateWritableString -- Creates storage for a string literal. 1743 static llvm::Constant *GenerateStringLiteral(const std::string &str, 1744 bool constant, 1745 CodeGenModule &CGM, 1746 const char *GlobalName) { 1747 // Create Constant for this string literal. Don't add a '\0'. 1748 llvm::Constant *C = 1749 llvm::ConstantArray::get(CGM.getLLVMContext(), str, false); 1750 1751 // Create a global variable for this string 1752 llvm::GlobalVariable *GV = 1753 new llvm::GlobalVariable(CGM.getModule(), C->getType(), constant, 1754 llvm::GlobalValue::PrivateLinkage, 1755 C, GlobalName); 1756 GV->setUnnamedAddr(true); 1757 return GV; 1758 } 1759 1760 /// GetAddrOfConstantString - Returns a pointer to a character array 1761 /// containing the literal. This contents are exactly that of the 1762 /// given string, i.e. it will not be null terminated automatically; 1763 /// see GetAddrOfConstantCString. Note that whether the result is 1764 /// actually a pointer to an LLVM constant depends on 1765 /// Feature.WriteableStrings. 1766 /// 1767 /// The result has pointer to array type. 1768 llvm::Constant *CodeGenModule::GetAddrOfConstantString(const std::string &str, 1769 const char *GlobalName) { 1770 bool IsConstant = !Features.WritableStrings; 1771 1772 // Get the default prefix if a name wasn't specified. 1773 if (!GlobalName) 1774 GlobalName = ".str"; 1775 1776 // Don't share any string literals if strings aren't constant. 1777 if (!IsConstant) 1778 return GenerateStringLiteral(str, false, *this, GlobalName); 1779 1780 llvm::StringMapEntry<llvm::Constant *> &Entry = 1781 ConstantStringMap.GetOrCreateValue(&str[0], &str[str.length()]); 1782 1783 if (Entry.getValue()) 1784 return Entry.getValue(); 1785 1786 // Create a global variable for this. 1787 llvm::Constant *C = GenerateStringLiteral(str, true, *this, GlobalName); 1788 Entry.setValue(C); 1789 return C; 1790 } 1791 1792 /// GetAddrOfConstantCString - Returns a pointer to a character 1793 /// array containing the literal and a terminating '\-' 1794 /// character. The result has pointer to array type. 1795 llvm::Constant *CodeGenModule::GetAddrOfConstantCString(const std::string &str, 1796 const char *GlobalName){ 1797 return GetAddrOfConstantString(str + '\0', GlobalName); 1798 } 1799 1800 /// EmitObjCPropertyImplementations - Emit information for synthesized 1801 /// properties for an implementation. 1802 void CodeGenModule::EmitObjCPropertyImplementations(const 1803 ObjCImplementationDecl *D) { 1804 for (ObjCImplementationDecl::propimpl_iterator 1805 i = D->propimpl_begin(), e = D->propimpl_end(); i != e; ++i) { 1806 ObjCPropertyImplDecl *PID = *i; 1807 1808 // Dynamic is just for type-checking. 1809 if (PID->getPropertyImplementation() == ObjCPropertyImplDecl::Synthesize) { 1810 ObjCPropertyDecl *PD = PID->getPropertyDecl(); 1811 1812 // Determine which methods need to be implemented, some may have 1813 // been overridden. Note that ::isSynthesized is not the method 1814 // we want, that just indicates if the decl came from a 1815 // property. What we want to know is if the method is defined in 1816 // this implementation. 1817 if (!D->getInstanceMethod(PD->getGetterName())) 1818 CodeGenFunction(*this).GenerateObjCGetter( 1819 const_cast<ObjCImplementationDecl *>(D), PID); 1820 if (!PD->isReadOnly() && 1821 !D->getInstanceMethod(PD->getSetterName())) 1822 CodeGenFunction(*this).GenerateObjCSetter( 1823 const_cast<ObjCImplementationDecl *>(D), PID); 1824 } 1825 } 1826 } 1827 1828 /// EmitObjCIvarInitializations - Emit information for ivar initialization 1829 /// for an implementation. 1830 void CodeGenModule::EmitObjCIvarInitializations(ObjCImplementationDecl *D) { 1831 if (!Features.NeXTRuntime || D->getNumIvarInitializers() == 0) 1832 return; 1833 DeclContext* DC = const_cast<DeclContext*>(dyn_cast<DeclContext>(D)); 1834 assert(DC && "EmitObjCIvarInitializations - null DeclContext"); 1835 IdentifierInfo *II = &getContext().Idents.get(".cxx_destruct"); 1836 Selector cxxSelector = getContext().Selectors.getSelector(0, &II); 1837 ObjCMethodDecl *DTORMethod = ObjCMethodDecl::Create(getContext(), 1838 D->getLocation(), 1839 D->getLocation(), cxxSelector, 1840 getContext().VoidTy, 0, 1841 DC, true, false, true, false, 1842 ObjCMethodDecl::Required); 1843 D->addInstanceMethod(DTORMethod); 1844 CodeGenFunction(*this).GenerateObjCCtorDtorMethod(D, DTORMethod, false); 1845 1846 II = &getContext().Idents.get(".cxx_construct"); 1847 cxxSelector = getContext().Selectors.getSelector(0, &II); 1848 // The constructor returns 'self'. 1849 ObjCMethodDecl *CTORMethod = ObjCMethodDecl::Create(getContext(), 1850 D->getLocation(), 1851 D->getLocation(), cxxSelector, 1852 getContext().getObjCIdType(), 0, 1853 DC, true, false, true, false, 1854 ObjCMethodDecl::Required); 1855 D->addInstanceMethod(CTORMethod); 1856 CodeGenFunction(*this).GenerateObjCCtorDtorMethod(D, CTORMethod, true); 1857 1858 1859 } 1860 1861 /// EmitNamespace - Emit all declarations in a namespace. 1862 void CodeGenModule::EmitNamespace(const NamespaceDecl *ND) { 1863 for (RecordDecl::decl_iterator I = ND->decls_begin(), E = ND->decls_end(); 1864 I != E; ++I) 1865 EmitTopLevelDecl(*I); 1866 } 1867 1868 // EmitLinkageSpec - Emit all declarations in a linkage spec. 1869 void CodeGenModule::EmitLinkageSpec(const LinkageSpecDecl *LSD) { 1870 if (LSD->getLanguage() != LinkageSpecDecl::lang_c && 1871 LSD->getLanguage() != LinkageSpecDecl::lang_cxx) { 1872 ErrorUnsupported(LSD, "linkage spec"); 1873 return; 1874 } 1875 1876 for (RecordDecl::decl_iterator I = LSD->decls_begin(), E = LSD->decls_end(); 1877 I != E; ++I) 1878 EmitTopLevelDecl(*I); 1879 } 1880 1881 /// EmitTopLevelDecl - Emit code for a single top level declaration. 1882 void CodeGenModule::EmitTopLevelDecl(Decl *D) { 1883 // If an error has occurred, stop code generation, but continue 1884 // parsing and semantic analysis (to ensure all warnings and errors 1885 // are emitted). 1886 if (Diags.hasErrorOccurred()) 1887 return; 1888 1889 // Ignore dependent declarations. 1890 if (D->getDeclContext() && D->getDeclContext()->isDependentContext()) 1891 return; 1892 1893 switch (D->getKind()) { 1894 case Decl::CXXConversion: 1895 case Decl::CXXMethod: 1896 case Decl::Function: 1897 // Skip function templates 1898 if (cast<FunctionDecl>(D)->getDescribedFunctionTemplate()) 1899 return; 1900 1901 EmitGlobal(cast<FunctionDecl>(D)); 1902 break; 1903 1904 case Decl::Var: 1905 EmitGlobal(cast<VarDecl>(D)); 1906 break; 1907 1908 // C++ Decls 1909 case Decl::Namespace: 1910 EmitNamespace(cast<NamespaceDecl>(D)); 1911 break; 1912 // No code generation needed. 1913 case Decl::UsingShadow: 1914 case Decl::Using: 1915 case Decl::UsingDirective: 1916 case Decl::ClassTemplate: 1917 case Decl::FunctionTemplate: 1918 case Decl::NamespaceAlias: 1919 break; 1920 case Decl::CXXConstructor: 1921 // Skip function templates 1922 if (cast<FunctionDecl>(D)->getDescribedFunctionTemplate()) 1923 return; 1924 1925 EmitCXXConstructors(cast<CXXConstructorDecl>(D)); 1926 break; 1927 case Decl::CXXDestructor: 1928 EmitCXXDestructors(cast<CXXDestructorDecl>(D)); 1929 break; 1930 1931 case Decl::StaticAssert: 1932 // Nothing to do. 1933 break; 1934 1935 // Objective-C Decls 1936 1937 // Forward declarations, no (immediate) code generation. 1938 case Decl::ObjCClass: 1939 case Decl::ObjCForwardProtocol: 1940 case Decl::ObjCInterface: 1941 break; 1942 1943 case Decl::ObjCCategory: { 1944 ObjCCategoryDecl *CD = cast<ObjCCategoryDecl>(D); 1945 if (CD->IsClassExtension() && CD->hasSynthBitfield()) 1946 Context.ResetObjCLayout(CD->getClassInterface()); 1947 break; 1948 } 1949 1950 1951 case Decl::ObjCProtocol: 1952 Runtime->GenerateProtocol(cast<ObjCProtocolDecl>(D)); 1953 break; 1954 1955 case Decl::ObjCCategoryImpl: 1956 // Categories have properties but don't support synthesize so we 1957 // can ignore them here. 1958 Runtime->GenerateCategory(cast<ObjCCategoryImplDecl>(D)); 1959 break; 1960 1961 case Decl::ObjCImplementation: { 1962 ObjCImplementationDecl *OMD = cast<ObjCImplementationDecl>(D); 1963 if (Features.ObjCNonFragileABI2 && OMD->hasSynthBitfield()) 1964 Context.ResetObjCLayout(OMD->getClassInterface()); 1965 EmitObjCPropertyImplementations(OMD); 1966 EmitObjCIvarInitializations(OMD); 1967 Runtime->GenerateClass(OMD); 1968 break; 1969 } 1970 case Decl::ObjCMethod: { 1971 ObjCMethodDecl *OMD = cast<ObjCMethodDecl>(D); 1972 // If this is not a prototype, emit the body. 1973 if (OMD->getBody()) 1974 CodeGenFunction(*this).GenerateObjCMethod(OMD); 1975 break; 1976 } 1977 case Decl::ObjCCompatibleAlias: 1978 // compatibility-alias is a directive and has no code gen. 1979 break; 1980 1981 case Decl::LinkageSpec: 1982 EmitLinkageSpec(cast<LinkageSpecDecl>(D)); 1983 break; 1984 1985 case Decl::FileScopeAsm: { 1986 FileScopeAsmDecl *AD = cast<FileScopeAsmDecl>(D); 1987 llvm::StringRef AsmString = AD->getAsmString()->getString(); 1988 1989 const std::string &S = getModule().getModuleInlineAsm(); 1990 if (S.empty()) 1991 getModule().setModuleInlineAsm(AsmString); 1992 else 1993 getModule().setModuleInlineAsm(S + '\n' + AsmString.str()); 1994 break; 1995 } 1996 1997 default: 1998 // Make sure we handled everything we should, every other kind is a 1999 // non-top-level decl. FIXME: Would be nice to have an isTopLevelDeclKind 2000 // function. Need to recode Decl::Kind to do that easily. 2001 assert(isa<TypeDecl>(D) && "Unsupported decl kind"); 2002 } 2003 } 2004 2005 /// Turns the given pointer into a constant. 2006 static llvm::Constant *GetPointerConstant(llvm::LLVMContext &Context, 2007 const void *Ptr) { 2008 uintptr_t PtrInt = reinterpret_cast<uintptr_t>(Ptr); 2009 const llvm::Type *i64 = llvm::Type::getInt64Ty(Context); 2010 return llvm::ConstantInt::get(i64, PtrInt); 2011 } 2012 2013 static void EmitGlobalDeclMetadata(CodeGenModule &CGM, 2014 llvm::NamedMDNode *&GlobalMetadata, 2015 GlobalDecl D, 2016 llvm::GlobalValue *Addr) { 2017 if (!GlobalMetadata) 2018 GlobalMetadata = 2019 CGM.getModule().getOrInsertNamedMetadata("clang.global.decl.ptrs"); 2020 2021 // TODO: should we report variant information for ctors/dtors? 2022 llvm::Value *Ops[] = { 2023 Addr, 2024 GetPointerConstant(CGM.getLLVMContext(), D.getDecl()) 2025 }; 2026 GlobalMetadata->addOperand(llvm::MDNode::get(CGM.getLLVMContext(), Ops, 2)); 2027 } 2028 2029 /// Emits metadata nodes associating all the global values in the 2030 /// current module with the Decls they came from. This is useful for 2031 /// projects using IR gen as a subroutine. 2032 /// 2033 /// Since there's currently no way to associate an MDNode directly 2034 /// with an llvm::GlobalValue, we create a global named metadata 2035 /// with the name 'clang.global.decl.ptrs'. 2036 void CodeGenModule::EmitDeclMetadata() { 2037 llvm::NamedMDNode *GlobalMetadata = 0; 2038 2039 // StaticLocalDeclMap 2040 for (llvm::DenseMap<GlobalDecl,llvm::StringRef>::iterator 2041 I = MangledDeclNames.begin(), E = MangledDeclNames.end(); 2042 I != E; ++I) { 2043 llvm::GlobalValue *Addr = getModule().getNamedValue(I->second); 2044 EmitGlobalDeclMetadata(*this, GlobalMetadata, I->first, Addr); 2045 } 2046 } 2047 2048 /// Emits metadata nodes for all the local variables in the current 2049 /// function. 2050 void CodeGenFunction::EmitDeclMetadata() { 2051 if (LocalDeclMap.empty()) return; 2052 2053 llvm::LLVMContext &Context = getLLVMContext(); 2054 2055 // Find the unique metadata ID for this name. 2056 unsigned DeclPtrKind = Context.getMDKindID("clang.decl.ptr"); 2057 2058 llvm::NamedMDNode *GlobalMetadata = 0; 2059 2060 for (llvm::DenseMap<const Decl*, llvm::Value*>::iterator 2061 I = LocalDeclMap.begin(), E = LocalDeclMap.end(); I != E; ++I) { 2062 const Decl *D = I->first; 2063 llvm::Value *Addr = I->second; 2064 2065 if (llvm::AllocaInst *Alloca = dyn_cast<llvm::AllocaInst>(Addr)) { 2066 llvm::Value *DAddr = GetPointerConstant(getLLVMContext(), D); 2067 Alloca->setMetadata(DeclPtrKind, llvm::MDNode::get(Context, &DAddr, 1)); 2068 } else if (llvm::GlobalValue *GV = dyn_cast<llvm::GlobalValue>(Addr)) { 2069 GlobalDecl GD = GlobalDecl(cast<VarDecl>(D)); 2070 EmitGlobalDeclMetadata(CGM, GlobalMetadata, GD, GV); 2071 } 2072 } 2073 } 2074 2075 ///@name Custom Runtime Function Interfaces 2076 ///@{ 2077 // 2078 // FIXME: These can be eliminated once we can have clients just get the required 2079 // AST nodes from the builtin tables. 2080 2081 llvm::Constant *CodeGenModule::getBlockObjectDispose() { 2082 if (BlockObjectDispose) 2083 return BlockObjectDispose; 2084 2085 // If we saw an explicit decl, use that. 2086 if (BlockObjectDisposeDecl) { 2087 return BlockObjectDispose = GetAddrOfFunction( 2088 BlockObjectDisposeDecl, 2089 getTypes().GetFunctionType(BlockObjectDisposeDecl)); 2090 } 2091 2092 // Otherwise construct the function by hand. 2093 const llvm::FunctionType *FTy; 2094 std::vector<const llvm::Type*> ArgTys; 2095 const llvm::Type *ResultType = llvm::Type::getVoidTy(VMContext); 2096 ArgTys.push_back(PtrToInt8Ty); 2097 ArgTys.push_back(llvm::Type::getInt32Ty(VMContext)); 2098 FTy = llvm::FunctionType::get(ResultType, ArgTys, false); 2099 return BlockObjectDispose = 2100 CreateRuntimeFunction(FTy, "_Block_object_dispose"); 2101 } 2102 2103 llvm::Constant *CodeGenModule::getBlockObjectAssign() { 2104 if (BlockObjectAssign) 2105 return BlockObjectAssign; 2106 2107 // If we saw an explicit decl, use that. 2108 if (BlockObjectAssignDecl) { 2109 return BlockObjectAssign = GetAddrOfFunction( 2110 BlockObjectAssignDecl, 2111 getTypes().GetFunctionType(BlockObjectAssignDecl)); 2112 } 2113 2114 // Otherwise construct the function by hand. 2115 const llvm::FunctionType *FTy; 2116 std::vector<const llvm::Type*> ArgTys; 2117 const llvm::Type *ResultType = llvm::Type::getVoidTy(VMContext); 2118 ArgTys.push_back(PtrToInt8Ty); 2119 ArgTys.push_back(PtrToInt8Ty); 2120 ArgTys.push_back(llvm::Type::getInt32Ty(VMContext)); 2121 FTy = llvm::FunctionType::get(ResultType, ArgTys, false); 2122 return BlockObjectAssign = 2123 CreateRuntimeFunction(FTy, "_Block_object_assign"); 2124 } 2125 2126 llvm::Constant *CodeGenModule::getNSConcreteGlobalBlock() { 2127 if (NSConcreteGlobalBlock) 2128 return NSConcreteGlobalBlock; 2129 2130 // If we saw an explicit decl, use that. 2131 if (NSConcreteGlobalBlockDecl) { 2132 return NSConcreteGlobalBlock = GetAddrOfGlobalVar( 2133 NSConcreteGlobalBlockDecl, 2134 getTypes().ConvertType(NSConcreteGlobalBlockDecl->getType())); 2135 } 2136 2137 // Otherwise construct the variable by hand. 2138 return NSConcreteGlobalBlock = CreateRuntimeVariable( 2139 PtrToInt8Ty, "_NSConcreteGlobalBlock"); 2140 } 2141 2142 llvm::Constant *CodeGenModule::getNSConcreteStackBlock() { 2143 if (NSConcreteStackBlock) 2144 return NSConcreteStackBlock; 2145 2146 // If we saw an explicit decl, use that. 2147 if (NSConcreteStackBlockDecl) { 2148 return NSConcreteStackBlock = GetAddrOfGlobalVar( 2149 NSConcreteStackBlockDecl, 2150 getTypes().ConvertType(NSConcreteStackBlockDecl->getType())); 2151 } 2152 2153 // Otherwise construct the variable by hand. 2154 return NSConcreteStackBlock = CreateRuntimeVariable( 2155 PtrToInt8Ty, "_NSConcreteStackBlock"); 2156 } 2157 2158 ///@} 2159