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