CodeGenModule.cpp revision 7a536907da776bdc47a704e7cafd641e8150e653
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 "CGCall.h" 18#include "CGObjCRuntime.h" 19#include "Mangle.h" 20#include "TargetInfo.h" 21#include "clang/Frontend/CodeGenOptions.h" 22#include "clang/AST/ASTContext.h" 23#include "clang/AST/CharUnits.h" 24#include "clang/AST/DeclObjC.h" 25#include "clang/AST/DeclCXX.h" 26#include "clang/AST/DeclTemplate.h" 27#include "clang/AST/RecordLayout.h" 28#include "clang/Basic/Builtins.h" 29#include "clang/Basic/Diagnostic.h" 30#include "clang/Basic/SourceManager.h" 31#include "clang/Basic/TargetInfo.h" 32#include "clang/Basic/ConvertUTF.h" 33#include "llvm/CallingConv.h" 34#include "llvm/Module.h" 35#include "llvm/Intrinsics.h" 36#include "llvm/LLVMContext.h" 37#include "llvm/ADT/Triple.h" 38#include "llvm/Target/TargetData.h" 39#include "llvm/Support/CallSite.h" 40#include "llvm/Support/ErrorHandling.h" 41using namespace clang; 42using namespace CodeGen; 43 44 45CodeGenModule::CodeGenModule(ASTContext &C, const CodeGenOptions &CGO, 46 llvm::Module &M, const llvm::TargetData &TD, 47 Diagnostic &diags) 48 : BlockModule(C, M, TD, Types, *this), Context(C), 49 Features(C.getLangOptions()), CodeGenOpts(CGO), TheModule(M), 50 TheTargetData(TD), TheTargetCodeGenInfo(0), Diags(diags), 51 Types(C, M, TD, getTargetCodeGenInfo().getABIInfo()), 52 VTables(*this), Runtime(0), ABI(0), 53 CFConstantStringClassRef(0), NSConstantStringClassRef(0), 54 VMContext(M.getContext()), 55 NSConcreteGlobalBlockDecl(0), NSConcreteStackBlockDecl(0), 56 NSConcreteGlobalBlock(0), NSConcreteStackBlock(0), 57 BlockObjectAssignDecl(0), BlockObjectDisposeDecl(0), 58 BlockObjectAssign(0), BlockObjectDispose(0){ 59 60 if (!Features.ObjC1) 61 Runtime = 0; 62 else if (!Features.NeXTRuntime) 63 Runtime = CreateGNUObjCRuntime(*this); 64 else if (Features.ObjCNonFragileABI) 65 Runtime = CreateMacNonFragileABIObjCRuntime(*this); 66 else 67 Runtime = CreateMacObjCRuntime(*this); 68 69 if (!Features.CPlusPlus) 70 ABI = 0; 71 else createCXXABI(); 72 73 // If debug info generation is enabled, create the CGDebugInfo object. 74 DebugInfo = CodeGenOpts.DebugInfo ? new CGDebugInfo(*this) : 0; 75} 76 77CodeGenModule::~CodeGenModule() { 78 delete Runtime; 79 delete ABI; 80 delete DebugInfo; 81} 82 83void CodeGenModule::createObjCRuntime() { 84 if (!Features.NeXTRuntime) 85 Runtime = CreateGNUObjCRuntime(*this); 86 else if (Features.ObjCNonFragileABI) 87 Runtime = CreateMacNonFragileABIObjCRuntime(*this); 88 else 89 Runtime = CreateMacObjCRuntime(*this); 90} 91 92void CodeGenModule::createCXXABI() { 93 if (Context.Target.getCXXABI() == "microsoft") 94 ABI = CreateMicrosoftCXXABI(*this); 95 else 96 ABI = CreateItaniumCXXABI(*this); 97} 98 99void CodeGenModule::Release() { 100 EmitDeferred(); 101 EmitCXXGlobalInitFunc(); 102 EmitCXXGlobalDtorFunc(); 103 if (Runtime) 104 if (llvm::Function *ObjCInitFunction = Runtime->ModuleInitFunction()) 105 AddGlobalCtor(ObjCInitFunction); 106 EmitCtorList(GlobalCtors, "llvm.global_ctors"); 107 EmitCtorList(GlobalDtors, "llvm.global_dtors"); 108 EmitAnnotations(); 109 EmitLLVMUsed(); 110 111 if (getCodeGenOpts().EmitDeclMetadata) 112 EmitDeclMetadata(); 113} 114 115bool CodeGenModule::isTargetDarwin() const { 116 return getContext().Target.getTriple().getOS() == llvm::Triple::Darwin; 117} 118 119/// ErrorUnsupported - Print out an error that codegen doesn't support the 120/// specified stmt yet. 121void CodeGenModule::ErrorUnsupported(const Stmt *S, const char *Type, 122 bool OmitOnError) { 123 if (OmitOnError && getDiags().hasErrorOccurred()) 124 return; 125 unsigned DiagID = getDiags().getCustomDiagID(Diagnostic::Error, 126 "cannot compile this %0 yet"); 127 std::string Msg = Type; 128 getDiags().Report(Context.getFullLoc(S->getLocStart()), DiagID) 129 << Msg << S->getSourceRange(); 130} 131 132/// ErrorUnsupported - Print out an error that codegen doesn't support the 133/// specified decl yet. 134void CodeGenModule::ErrorUnsupported(const Decl *D, const char *Type, 135 bool OmitOnError) { 136 if (OmitOnError && getDiags().hasErrorOccurred()) 137 return; 138 unsigned DiagID = getDiags().getCustomDiagID(Diagnostic::Error, 139 "cannot compile this %0 yet"); 140 std::string Msg = Type; 141 getDiags().Report(Context.getFullLoc(D->getLocation()), DiagID) << Msg; 142} 143 144LangOptions::VisibilityMode 145CodeGenModule::getDeclVisibilityMode(const Decl *D) const { 146 if (const VarDecl *VD = dyn_cast<VarDecl>(D)) 147 if (VD->getStorageClass() == VarDecl::PrivateExtern) 148 return LangOptions::Hidden; 149 150 if (const VisibilityAttr *attr = D->getAttr<VisibilityAttr>()) { 151 switch (attr->getVisibility()) { 152 default: assert(0 && "Unknown visibility!"); 153 case VisibilityAttr::DefaultVisibility: 154 return LangOptions::Default; 155 case VisibilityAttr::HiddenVisibility: 156 return LangOptions::Hidden; 157 case VisibilityAttr::ProtectedVisibility: 158 return LangOptions::Protected; 159 } 160 } 161 162 if (getLangOptions().CPlusPlus) { 163 // Entities subject to an explicit instantiation declaration get default 164 // visibility. 165 if (const FunctionDecl *Function = dyn_cast<FunctionDecl>(D)) { 166 if (Function->getTemplateSpecializationKind() 167 == TSK_ExplicitInstantiationDeclaration) 168 return LangOptions::Default; 169 } else if (const ClassTemplateSpecializationDecl *ClassSpec 170 = dyn_cast<ClassTemplateSpecializationDecl>(D)) { 171 if (ClassSpec->getSpecializationKind() 172 == TSK_ExplicitInstantiationDeclaration) 173 return LangOptions::Default; 174 } else if (const CXXRecordDecl *Record = dyn_cast<CXXRecordDecl>(D)) { 175 if (Record->getTemplateSpecializationKind() 176 == TSK_ExplicitInstantiationDeclaration) 177 return LangOptions::Default; 178 } else if (const VarDecl *Var = dyn_cast<VarDecl>(D)) { 179 if (Var->isStaticDataMember() && 180 (Var->getTemplateSpecializationKind() 181 == TSK_ExplicitInstantiationDeclaration)) 182 return LangOptions::Default; 183 } 184 185 // If -fvisibility-inlines-hidden was provided, then inline C++ member 186 // functions get "hidden" visibility by default. 187 if (getLangOptions().InlineVisibilityHidden) 188 if (const CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(D)) 189 if (Method->isInlined()) 190 return LangOptions::Hidden; 191 } 192 193 // If this decl is contained in a class, it should have the same visibility 194 // as the parent class. 195 if (const DeclContext *DC = D->getDeclContext()) 196 if (DC->isRecord()) 197 return getDeclVisibilityMode(cast<Decl>(DC)); 198 199 return getLangOptions().getVisibilityMode(); 200} 201 202void CodeGenModule::setGlobalVisibility(llvm::GlobalValue *GV, 203 const Decl *D) const { 204 // Internal definitions always have default visibility. 205 if (GV->hasLocalLinkage()) { 206 GV->setVisibility(llvm::GlobalValue::DefaultVisibility); 207 return; 208 } 209 210 switch (getDeclVisibilityMode(D)) { 211 default: assert(0 && "Unknown visibility!"); 212 case LangOptions::Default: 213 return GV->setVisibility(llvm::GlobalValue::DefaultVisibility); 214 case LangOptions::Hidden: 215 return GV->setVisibility(llvm::GlobalValue::HiddenVisibility); 216 case LangOptions::Protected: 217 return GV->setVisibility(llvm::GlobalValue::ProtectedVisibility); 218 } 219} 220 221/// Set the symbol visibility of type information (vtable and RTTI) 222/// associated with the given type. 223void CodeGenModule::setTypeVisibility(llvm::GlobalValue *GV, 224 const CXXRecordDecl *RD, 225 bool IsForRTTI) const { 226 setGlobalVisibility(GV, RD); 227 228 // We want to drop the visibility to hidden for weak type symbols. 229 // This isn't possible if there might be unresolved references 230 // elsewhere that rely on this symbol being visible. 231 232 // This should be kept roughly in sync with setThunkVisibility 233 // in CGVTables.cpp. 234 235 // Preconditions. 236 if (GV->getLinkage() != llvm::GlobalVariable::WeakODRLinkage || 237 GV->getVisibility() != llvm::GlobalVariable::DefaultVisibility) 238 return; 239 240 // Don't override an explicit visibility attribute. 241 if (RD->hasAttr<VisibilityAttr>()) 242 return; 243 244 switch (RD->getTemplateSpecializationKind()) { 245 // We have to disable the optimization if this is an EI definition 246 // because there might be EI declarations in other shared objects. 247 case TSK_ExplicitInstantiationDefinition: 248 case TSK_ExplicitInstantiationDeclaration: 249 return; 250 251 // Every use of a non-template class's type information has to emit it. 252 case TSK_Undeclared: 253 break; 254 255 // In theory, implicit instantiations can ignore the possibility of 256 // an explicit instantiation declaration because there necessarily 257 // must be an EI definition somewhere with default visibility. In 258 // practice, it's possible to have an explicit instantiation for 259 // an arbitrary template class, and linkers aren't necessarily able 260 // to deal with mixed-visibility symbols. 261 case TSK_ExplicitSpecialization: 262 case TSK_ImplicitInstantiation: 263 if (!CodeGenOpts.EmitWeakTemplatesHidden) 264 return; 265 break; 266 } 267 268 // If there's a key function, there may be translation units 269 // that don't have the key function's definition. But ignore 270 // this if we're emitting RTTI under -fno-rtti. 271 if (!IsForRTTI || Features.RTTI) 272 if (Context.getKeyFunction(RD)) 273 return; 274 275 // Otherwise, drop the visibility to hidden. 276 GV->setVisibility(llvm::GlobalValue::HiddenVisibility); 277} 278 279llvm::StringRef CodeGenModule::getMangledName(GlobalDecl GD) { 280 const NamedDecl *ND = cast<NamedDecl>(GD.getDecl()); 281 282 llvm::StringRef &Str = MangledDeclNames[GD.getCanonicalDecl()]; 283 if (!Str.empty()) 284 return Str; 285 286 if (!getMangleContext().shouldMangleDeclName(ND)) { 287 IdentifierInfo *II = ND->getIdentifier(); 288 assert(II && "Attempt to mangle unnamed decl."); 289 290 Str = II->getName(); 291 return Str; 292 } 293 294 llvm::SmallString<256> Buffer; 295 if (const CXXConstructorDecl *D = dyn_cast<CXXConstructorDecl>(ND)) 296 getMangleContext().mangleCXXCtor(D, GD.getCtorType(), Buffer); 297 else if (const CXXDestructorDecl *D = dyn_cast<CXXDestructorDecl>(ND)) 298 getMangleContext().mangleCXXDtor(D, GD.getDtorType(), Buffer); 299 else if (const BlockDecl *BD = dyn_cast<BlockDecl>(ND)) 300 getMangleContext().mangleBlock(GD, BD, Buffer); 301 else 302 getMangleContext().mangleName(ND, Buffer); 303 304 // Allocate space for the mangled name. 305 size_t Length = Buffer.size(); 306 char *Name = MangledNamesAllocator.Allocate<char>(Length); 307 std::copy(Buffer.begin(), Buffer.end(), Name); 308 309 Str = llvm::StringRef(Name, Length); 310 311 return Str; 312} 313 314void CodeGenModule::getMangledName(GlobalDecl GD, MangleBuffer &Buffer, 315 const BlockDecl *BD) { 316 getMangleContext().mangleBlock(GD, BD, Buffer.getBuffer()); 317} 318 319llvm::GlobalValue *CodeGenModule::GetGlobalValue(llvm::StringRef Name) { 320 return getModule().getNamedValue(Name); 321} 322 323/// AddGlobalCtor - Add a function to the list that will be called before 324/// main() runs. 325void CodeGenModule::AddGlobalCtor(llvm::Function * Ctor, int Priority) { 326 // FIXME: Type coercion of void()* types. 327 GlobalCtors.push_back(std::make_pair(Ctor, Priority)); 328} 329 330/// AddGlobalDtor - Add a function to the list that will be called 331/// when the module is unloaded. 332void CodeGenModule::AddGlobalDtor(llvm::Function * Dtor, int Priority) { 333 // FIXME: Type coercion of void()* types. 334 GlobalDtors.push_back(std::make_pair(Dtor, Priority)); 335} 336 337void CodeGenModule::EmitCtorList(const CtorList &Fns, const char *GlobalName) { 338 // Ctor function type is void()*. 339 llvm::FunctionType* CtorFTy = 340 llvm::FunctionType::get(llvm::Type::getVoidTy(VMContext), 341 std::vector<const llvm::Type*>(), 342 false); 343 llvm::Type *CtorPFTy = llvm::PointerType::getUnqual(CtorFTy); 344 345 // Get the type of a ctor entry, { i32, void ()* }. 346 llvm::StructType* CtorStructTy = 347 llvm::StructType::get(VMContext, llvm::Type::getInt32Ty(VMContext), 348 llvm::PointerType::getUnqual(CtorFTy), NULL); 349 350 // Construct the constructor and destructor arrays. 351 std::vector<llvm::Constant*> Ctors; 352 for (CtorList::const_iterator I = Fns.begin(), E = Fns.end(); I != E; ++I) { 353 std::vector<llvm::Constant*> S; 354 S.push_back(llvm::ConstantInt::get(llvm::Type::getInt32Ty(VMContext), 355 I->second, false)); 356 S.push_back(llvm::ConstantExpr::getBitCast(I->first, CtorPFTy)); 357 Ctors.push_back(llvm::ConstantStruct::get(CtorStructTy, S)); 358 } 359 360 if (!Ctors.empty()) { 361 llvm::ArrayType *AT = llvm::ArrayType::get(CtorStructTy, Ctors.size()); 362 new llvm::GlobalVariable(TheModule, AT, false, 363 llvm::GlobalValue::AppendingLinkage, 364 llvm::ConstantArray::get(AT, Ctors), 365 GlobalName); 366 } 367} 368 369void CodeGenModule::EmitAnnotations() { 370 if (Annotations.empty()) 371 return; 372 373 // Create a new global variable for the ConstantStruct in the Module. 374 llvm::Constant *Array = 375 llvm::ConstantArray::get(llvm::ArrayType::get(Annotations[0]->getType(), 376 Annotations.size()), 377 Annotations); 378 llvm::GlobalValue *gv = 379 new llvm::GlobalVariable(TheModule, Array->getType(), false, 380 llvm::GlobalValue::AppendingLinkage, Array, 381 "llvm.global.annotations"); 382 gv->setSection("llvm.metadata"); 383} 384 385llvm::GlobalValue::LinkageTypes 386CodeGenModule::getFunctionLinkage(const FunctionDecl *D) { 387 GVALinkage Linkage = getContext().GetGVALinkageForFunction(D); 388 389 if (Linkage == GVA_Internal) 390 return llvm::Function::InternalLinkage; 391 392 if (D->hasAttr<DLLExportAttr>()) 393 return llvm::Function::DLLExportLinkage; 394 395 if (D->hasAttr<WeakAttr>()) 396 return llvm::Function::WeakAnyLinkage; 397 398 // In C99 mode, 'inline' functions are guaranteed to have a strong 399 // definition somewhere else, so we can use available_externally linkage. 400 if (Linkage == GVA_C99Inline) 401 return llvm::Function::AvailableExternallyLinkage; 402 403 // In C++, the compiler has to emit a definition in every translation unit 404 // that references the function. We should use linkonce_odr because 405 // a) if all references in this translation unit are optimized away, we 406 // don't need to codegen it. b) if the function persists, it needs to be 407 // merged with other definitions. c) C++ has the ODR, so we know the 408 // definition is dependable. 409 if (Linkage == GVA_CXXInline || Linkage == GVA_TemplateInstantiation) 410 return llvm::Function::LinkOnceODRLinkage; 411 412 // An explicit instantiation of a template has weak linkage, since 413 // explicit instantiations can occur in multiple translation units 414 // and must all be equivalent. However, we are not allowed to 415 // throw away these explicit instantiations. 416 if (Linkage == GVA_ExplicitTemplateInstantiation) 417 return llvm::Function::WeakODRLinkage; 418 419 // Otherwise, we have strong external linkage. 420 assert(Linkage == GVA_StrongExternal); 421 return llvm::Function::ExternalLinkage; 422} 423 424 425/// SetFunctionDefinitionAttributes - Set attributes for a global. 426/// 427/// FIXME: This is currently only done for aliases and functions, but not for 428/// variables (these details are set in EmitGlobalVarDefinition for variables). 429void CodeGenModule::SetFunctionDefinitionAttributes(const FunctionDecl *D, 430 llvm::GlobalValue *GV) { 431 SetCommonAttributes(D, GV); 432} 433 434void CodeGenModule::SetLLVMFunctionAttributes(const Decl *D, 435 const CGFunctionInfo &Info, 436 llvm::Function *F) { 437 unsigned CallingConv; 438 AttributeListType AttributeList; 439 ConstructAttributeList(Info, D, AttributeList, CallingConv); 440 F->setAttributes(llvm::AttrListPtr::get(AttributeList.begin(), 441 AttributeList.size())); 442 F->setCallingConv(static_cast<llvm::CallingConv::ID>(CallingConv)); 443} 444 445void CodeGenModule::SetLLVMFunctionAttributesForDefinition(const Decl *D, 446 llvm::Function *F) { 447 if (!Features.Exceptions && !Features.ObjCNonFragileABI) 448 F->addFnAttr(llvm::Attribute::NoUnwind); 449 450 if (D->hasAttr<AlwaysInlineAttr>()) 451 F->addFnAttr(llvm::Attribute::AlwaysInline); 452 453 if (D->hasAttr<NoInlineAttr>()) 454 F->addFnAttr(llvm::Attribute::NoInline); 455 456 if (Features.getStackProtectorMode() == LangOptions::SSPOn) 457 F->addFnAttr(llvm::Attribute::StackProtect); 458 else if (Features.getStackProtectorMode() == LangOptions::SSPReq) 459 F->addFnAttr(llvm::Attribute::StackProtectReq); 460 461 if (const AlignedAttr *AA = D->getAttr<AlignedAttr>()) { 462 unsigned width = Context.Target.getCharWidth(); 463 F->setAlignment(AA->getAlignment() / width); 464 while ((AA = AA->getNext<AlignedAttr>())) 465 F->setAlignment(std::max(F->getAlignment(), AA->getAlignment() / width)); 466 } 467 // C++ ABI requires 2-byte alignment for member functions. 468 if (F->getAlignment() < 2 && isa<CXXMethodDecl>(D)) 469 F->setAlignment(2); 470} 471 472void CodeGenModule::SetCommonAttributes(const Decl *D, 473 llvm::GlobalValue *GV) { 474 setGlobalVisibility(GV, D); 475 476 if (D->hasAttr<UsedAttr>()) 477 AddUsedGlobal(GV); 478 479 if (const SectionAttr *SA = D->getAttr<SectionAttr>()) 480 GV->setSection(SA->getName()); 481 482 getTargetCodeGenInfo().SetTargetAttributes(D, GV, *this); 483} 484 485void CodeGenModule::SetInternalFunctionAttributes(const Decl *D, 486 llvm::Function *F, 487 const CGFunctionInfo &FI) { 488 SetLLVMFunctionAttributes(D, FI, F); 489 SetLLVMFunctionAttributesForDefinition(D, F); 490 491 F->setLinkage(llvm::Function::InternalLinkage); 492 493 SetCommonAttributes(D, F); 494} 495 496void CodeGenModule::SetFunctionAttributes(GlobalDecl GD, 497 llvm::Function *F, 498 bool IsIncompleteFunction) { 499 const FunctionDecl *FD = cast<FunctionDecl>(GD.getDecl()); 500 501 if (!IsIncompleteFunction) 502 SetLLVMFunctionAttributes(FD, getTypes().getFunctionInfo(GD), F); 503 504 // Only a few attributes are set on declarations; these may later be 505 // overridden by a definition. 506 507 if (FD->hasAttr<DLLImportAttr>()) { 508 F->setLinkage(llvm::Function::DLLImportLinkage); 509 } else if (FD->hasAttr<WeakAttr>() || 510 FD->hasAttr<WeakImportAttr>()) { 511 // "extern_weak" is overloaded in LLVM; we probably should have 512 // separate linkage types for this. 513 F->setLinkage(llvm::Function::ExternalWeakLinkage); 514 } else { 515 F->setLinkage(llvm::Function::ExternalLinkage); 516 } 517 518 if (const SectionAttr *SA = FD->getAttr<SectionAttr>()) 519 F->setSection(SA->getName()); 520} 521 522void CodeGenModule::AddUsedGlobal(llvm::GlobalValue *GV) { 523 assert(!GV->isDeclaration() && 524 "Only globals with definition can force usage."); 525 LLVMUsed.push_back(GV); 526} 527 528void CodeGenModule::EmitLLVMUsed() { 529 // Don't create llvm.used if there is no need. 530 if (LLVMUsed.empty()) 531 return; 532 533 const llvm::Type *i8PTy = llvm::Type::getInt8PtrTy(VMContext); 534 535 // Convert LLVMUsed to what ConstantArray needs. 536 std::vector<llvm::Constant*> UsedArray; 537 UsedArray.resize(LLVMUsed.size()); 538 for (unsigned i = 0, e = LLVMUsed.size(); i != e; ++i) { 539 UsedArray[i] = 540 llvm::ConstantExpr::getBitCast(cast<llvm::Constant>(&*LLVMUsed[i]), 541 i8PTy); 542 } 543 544 if (UsedArray.empty()) 545 return; 546 llvm::ArrayType *ATy = llvm::ArrayType::get(i8PTy, UsedArray.size()); 547 548 llvm::GlobalVariable *GV = 549 new llvm::GlobalVariable(getModule(), ATy, false, 550 llvm::GlobalValue::AppendingLinkage, 551 llvm::ConstantArray::get(ATy, UsedArray), 552 "llvm.used"); 553 554 GV->setSection("llvm.metadata"); 555} 556 557void CodeGenModule::EmitDeferred() { 558 // Emit code for any potentially referenced deferred decls. Since a 559 // previously unused static decl may become used during the generation of code 560 // for a static function, iterate until no changes are made. 561 562 while (!DeferredDeclsToEmit.empty() || !DeferredVTables.empty()) { 563 if (!DeferredVTables.empty()) { 564 const CXXRecordDecl *RD = DeferredVTables.back(); 565 DeferredVTables.pop_back(); 566 getVTables().GenerateClassData(getVTableLinkage(RD), RD); 567 continue; 568 } 569 570 GlobalDecl D = DeferredDeclsToEmit.back(); 571 DeferredDeclsToEmit.pop_back(); 572 573 // Check to see if we've already emitted this. This is necessary 574 // for a couple of reasons: first, decls can end up in the 575 // deferred-decls queue multiple times, and second, decls can end 576 // up with definitions in unusual ways (e.g. by an extern inline 577 // function acquiring a strong function redefinition). Just 578 // ignore these cases. 579 // 580 // TODO: That said, looking this up multiple times is very wasteful. 581 llvm::StringRef Name = getMangledName(D); 582 llvm::GlobalValue *CGRef = GetGlobalValue(Name); 583 assert(CGRef && "Deferred decl wasn't referenced?"); 584 585 if (!CGRef->isDeclaration()) 586 continue; 587 588 // GlobalAlias::isDeclaration() defers to the aliasee, but for our 589 // purposes an alias counts as a definition. 590 if (isa<llvm::GlobalAlias>(CGRef)) 591 continue; 592 593 // Otherwise, emit the definition and move on to the next one. 594 EmitGlobalDefinition(D); 595 } 596} 597 598/// EmitAnnotateAttr - Generate the llvm::ConstantStruct which contains the 599/// annotation information for a given GlobalValue. The annotation struct is 600/// {i8 *, i8 *, i8 *, i32}. The first field is a constant expression, the 601/// GlobalValue being annotated. The second field is the constant string 602/// created from the AnnotateAttr's annotation. The third field is a constant 603/// string containing the name of the translation unit. The fourth field is 604/// the line number in the file of the annotated value declaration. 605/// 606/// FIXME: this does not unique the annotation string constants, as llvm-gcc 607/// appears to. 608/// 609llvm::Constant *CodeGenModule::EmitAnnotateAttr(llvm::GlobalValue *GV, 610 const AnnotateAttr *AA, 611 unsigned LineNo) { 612 llvm::Module *M = &getModule(); 613 614 // get [N x i8] constants for the annotation string, and the filename string 615 // which are the 2nd and 3rd elements of the global annotation structure. 616 const llvm::Type *SBP = llvm::Type::getInt8PtrTy(VMContext); 617 llvm::Constant *anno = llvm::ConstantArray::get(VMContext, 618 AA->getAnnotation(), true); 619 llvm::Constant *unit = llvm::ConstantArray::get(VMContext, 620 M->getModuleIdentifier(), 621 true); 622 623 // Get the two global values corresponding to the ConstantArrays we just 624 // created to hold the bytes of the strings. 625 llvm::GlobalValue *annoGV = 626 new llvm::GlobalVariable(*M, anno->getType(), false, 627 llvm::GlobalValue::PrivateLinkage, anno, 628 GV->getName()); 629 // translation unit name string, emitted into the llvm.metadata section. 630 llvm::GlobalValue *unitGV = 631 new llvm::GlobalVariable(*M, unit->getType(), false, 632 llvm::GlobalValue::PrivateLinkage, unit, 633 ".str"); 634 635 // Create the ConstantStruct for the global annotation. 636 llvm::Constant *Fields[4] = { 637 llvm::ConstantExpr::getBitCast(GV, SBP), 638 llvm::ConstantExpr::getBitCast(annoGV, SBP), 639 llvm::ConstantExpr::getBitCast(unitGV, SBP), 640 llvm::ConstantInt::get(llvm::Type::getInt32Ty(VMContext), LineNo) 641 }; 642 return llvm::ConstantStruct::get(VMContext, Fields, 4, false); 643} 644 645bool CodeGenModule::MayDeferGeneration(const ValueDecl *Global) { 646 // Never defer when EmitAllDecls is specified. 647 if (Features.EmitAllDecls) 648 return false; 649 650 return !getContext().DeclMustBeEmitted(Global); 651} 652 653llvm::Constant *CodeGenModule::GetWeakRefReference(const ValueDecl *VD) { 654 const AliasAttr *AA = VD->getAttr<AliasAttr>(); 655 assert(AA && "No alias?"); 656 657 const llvm::Type *DeclTy = getTypes().ConvertTypeForMem(VD->getType()); 658 659 // See if there is already something with the target's name in the module. 660 llvm::GlobalValue *Entry = GetGlobalValue(AA->getAliasee()); 661 662 llvm::Constant *Aliasee; 663 if (isa<llvm::FunctionType>(DeclTy)) 664 Aliasee = GetOrCreateLLVMFunction(AA->getAliasee(), DeclTy, GlobalDecl()); 665 else 666 Aliasee = GetOrCreateLLVMGlobal(AA->getAliasee(), 667 llvm::PointerType::getUnqual(DeclTy), 0); 668 if (!Entry) { 669 llvm::GlobalValue* F = cast<llvm::GlobalValue>(Aliasee); 670 F->setLinkage(llvm::Function::ExternalWeakLinkage); 671 WeakRefReferences.insert(F); 672 } 673 674 return Aliasee; 675} 676 677void CodeGenModule::EmitGlobal(GlobalDecl GD) { 678 const ValueDecl *Global = cast<ValueDecl>(GD.getDecl()); 679 680 // Weak references don't produce any output by themselves. 681 if (Global->hasAttr<WeakRefAttr>()) 682 return; 683 684 // If this is an alias definition (which otherwise looks like a declaration) 685 // emit it now. 686 if (Global->hasAttr<AliasAttr>()) 687 return EmitAliasDefinition(GD); 688 689 // Ignore declarations, they will be emitted on their first use. 690 if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(Global)) { 691 if (FD->getIdentifier()) { 692 llvm::StringRef Name = FD->getName(); 693 if (Name == "_Block_object_assign") { 694 BlockObjectAssignDecl = FD; 695 } else if (Name == "_Block_object_dispose") { 696 BlockObjectDisposeDecl = FD; 697 } 698 } 699 700 // Forward declarations are emitted lazily on first use. 701 if (!FD->isThisDeclarationADefinition()) 702 return; 703 } else { 704 const VarDecl *VD = cast<VarDecl>(Global); 705 assert(VD->isFileVarDecl() && "Cannot emit local var decl as global."); 706 707 if (VD->getIdentifier()) { 708 llvm::StringRef Name = VD->getName(); 709 if (Name == "_NSConcreteGlobalBlock") { 710 NSConcreteGlobalBlockDecl = VD; 711 } else if (Name == "_NSConcreteStackBlock") { 712 NSConcreteStackBlockDecl = VD; 713 } 714 } 715 716 717 if (VD->isThisDeclarationADefinition() != VarDecl::Definition) 718 return; 719 } 720 721 // Defer code generation when possible if this is a static definition, inline 722 // function etc. These we only want to emit if they are used. 723 if (!MayDeferGeneration(Global)) { 724 // Emit the definition if it can't be deferred. 725 EmitGlobalDefinition(GD); 726 return; 727 } 728 729 // If we're deferring emission of a C++ variable with an 730 // initializer, remember the order in which it appeared in the file. 731 if (getLangOptions().CPlusPlus && isa<VarDecl>(Global) && 732 cast<VarDecl>(Global)->hasInit()) { 733 DelayedCXXInitPosition[Global] = CXXGlobalInits.size(); 734 CXXGlobalInits.push_back(0); 735 } 736 737 // If the value has already been used, add it directly to the 738 // DeferredDeclsToEmit list. 739 llvm::StringRef MangledName = getMangledName(GD); 740 if (GetGlobalValue(MangledName)) 741 DeferredDeclsToEmit.push_back(GD); 742 else { 743 // Otherwise, remember that we saw a deferred decl with this name. The 744 // first use of the mangled name will cause it to move into 745 // DeferredDeclsToEmit. 746 DeferredDecls[MangledName] = GD; 747 } 748} 749 750void CodeGenModule::EmitGlobalDefinition(GlobalDecl GD) { 751 const ValueDecl *D = cast<ValueDecl>(GD.getDecl()); 752 753 PrettyStackTraceDecl CrashInfo(const_cast<ValueDecl *>(D), D->getLocation(), 754 Context.getSourceManager(), 755 "Generating code for declaration"); 756 757 if (const FunctionDecl *Function = dyn_cast<FunctionDecl>(D)) { 758 // At -O0, don't generate IR for functions with available_externally 759 // linkage. 760 if (CodeGenOpts.OptimizationLevel == 0 && 761 !Function->hasAttr<AlwaysInlineAttr>() && 762 getFunctionLinkage(Function) 763 == llvm::Function::AvailableExternallyLinkage) 764 return; 765 766 if (const CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(D)) { 767 if (Method->isVirtual()) 768 getVTables().EmitThunks(GD); 769 770 if (const CXXConstructorDecl *CD = dyn_cast<CXXConstructorDecl>(Method)) 771 return EmitCXXConstructor(CD, GD.getCtorType()); 772 773 if (const CXXDestructorDecl *DD = dyn_cast<CXXDestructorDecl>(Method)) 774 return EmitCXXDestructor(DD, GD.getDtorType()); 775 } 776 777 return EmitGlobalFunctionDefinition(GD); 778 } 779 780 if (const VarDecl *VD = dyn_cast<VarDecl>(D)) 781 return EmitGlobalVarDefinition(VD); 782 783 assert(0 && "Invalid argument to EmitGlobalDefinition()"); 784} 785 786/// GetOrCreateLLVMFunction - If the specified mangled name is not in the 787/// module, create and return an llvm Function with the specified type. If there 788/// is something in the module with the specified name, return it potentially 789/// bitcasted to the right type. 790/// 791/// If D is non-null, it specifies a decl that correspond to this. This is used 792/// to set the attributes on the function when it is first created. 793llvm::Constant * 794CodeGenModule::GetOrCreateLLVMFunction(llvm::StringRef MangledName, 795 const llvm::Type *Ty, 796 GlobalDecl D) { 797 // Lookup the entry, lazily creating it if necessary. 798 llvm::GlobalValue *Entry = GetGlobalValue(MangledName); 799 if (Entry) { 800 if (WeakRefReferences.count(Entry)) { 801 const FunctionDecl *FD = cast_or_null<FunctionDecl>(D.getDecl()); 802 if (FD && !FD->hasAttr<WeakAttr>()) 803 Entry->setLinkage(llvm::Function::ExternalLinkage); 804 805 WeakRefReferences.erase(Entry); 806 } 807 808 if (Entry->getType()->getElementType() == Ty) 809 return Entry; 810 811 // Make sure the result is of the correct type. 812 const llvm::Type *PTy = llvm::PointerType::getUnqual(Ty); 813 return llvm::ConstantExpr::getBitCast(Entry, PTy); 814 } 815 816 // This function doesn't have a complete type (for example, the return 817 // type is an incomplete struct). Use a fake type instead, and make 818 // sure not to try to set attributes. 819 bool IsIncompleteFunction = false; 820 821 const llvm::FunctionType *FTy; 822 if (isa<llvm::FunctionType>(Ty)) { 823 FTy = cast<llvm::FunctionType>(Ty); 824 } else { 825 FTy = llvm::FunctionType::get(llvm::Type::getVoidTy(VMContext), 826 std::vector<const llvm::Type*>(), false); 827 IsIncompleteFunction = true; 828 } 829 830 llvm::Function *F = llvm::Function::Create(FTy, 831 llvm::Function::ExternalLinkage, 832 MangledName, &getModule()); 833 assert(F->getName() == MangledName && "name was uniqued!"); 834 if (D.getDecl()) 835 SetFunctionAttributes(D, F, IsIncompleteFunction); 836 837 // This is the first use or definition of a mangled name. If there is a 838 // deferred decl with this name, remember that we need to emit it at the end 839 // of the file. 840 llvm::StringMap<GlobalDecl>::iterator DDI = DeferredDecls.find(MangledName); 841 if (DDI != DeferredDecls.end()) { 842 // Move the potentially referenced deferred decl to the DeferredDeclsToEmit 843 // list, and remove it from DeferredDecls (since we don't need it anymore). 844 DeferredDeclsToEmit.push_back(DDI->second); 845 DeferredDecls.erase(DDI); 846 } else if (const FunctionDecl *FD = cast_or_null<FunctionDecl>(D.getDecl())) { 847 // If this the first reference to a C++ inline function in a class, queue up 848 // the deferred function body for emission. These are not seen as 849 // top-level declarations. 850 if (FD->isThisDeclarationADefinition() && MayDeferGeneration(FD)) 851 DeferredDeclsToEmit.push_back(D); 852 // A called constructor which has no definition or declaration need be 853 // synthesized. 854 else if (const CXXConstructorDecl *CD = dyn_cast<CXXConstructorDecl>(FD)) { 855 if (CD->isImplicit()) { 856 assert(CD->isUsed() && "Sema doesn't consider constructor as used."); 857 DeferredDeclsToEmit.push_back(D); 858 } 859 } else if (const CXXDestructorDecl *DD = dyn_cast<CXXDestructorDecl>(FD)) { 860 if (DD->isImplicit()) { 861 assert(DD->isUsed() && "Sema doesn't consider destructor as used."); 862 DeferredDeclsToEmit.push_back(D); 863 } 864 } else if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(FD)) { 865 if (MD->isCopyAssignment() && MD->isImplicit()) { 866 assert(MD->isUsed() && "Sema doesn't consider CopyAssignment as used."); 867 DeferredDeclsToEmit.push_back(D); 868 } 869 } 870 } 871 872 // Make sure the result is of the requested type. 873 if (!IsIncompleteFunction) { 874 assert(F->getType()->getElementType() == Ty); 875 return F; 876 } 877 878 const llvm::Type *PTy = llvm::PointerType::getUnqual(Ty); 879 return llvm::ConstantExpr::getBitCast(F, PTy); 880} 881 882/// GetAddrOfFunction - Return the address of the given function. If Ty is 883/// non-null, then this function will use the specified type if it has to 884/// create it (this occurs when we see a definition of the function). 885llvm::Constant *CodeGenModule::GetAddrOfFunction(GlobalDecl GD, 886 const llvm::Type *Ty) { 887 // If there was no specific requested type, just convert it now. 888 if (!Ty) 889 Ty = getTypes().ConvertType(cast<ValueDecl>(GD.getDecl())->getType()); 890 891 llvm::StringRef MangledName = getMangledName(GD); 892 return GetOrCreateLLVMFunction(MangledName, Ty, GD); 893} 894 895/// CreateRuntimeFunction - Create a new runtime function with the specified 896/// type and name. 897llvm::Constant * 898CodeGenModule::CreateRuntimeFunction(const llvm::FunctionType *FTy, 899 llvm::StringRef Name) { 900 return GetOrCreateLLVMFunction(Name, FTy, GlobalDecl()); 901} 902 903static bool DeclIsConstantGlobal(ASTContext &Context, const VarDecl *D) { 904 if (!D->getType().isConstant(Context) && !D->getType()->isReferenceType()) 905 return false; 906 if (Context.getLangOptions().CPlusPlus && 907 Context.getBaseElementType(D->getType())->getAs<RecordType>()) { 908 // FIXME: We should do something fancier here! 909 return false; 910 } 911 return true; 912} 913 914/// GetOrCreateLLVMGlobal - If the specified mangled name is not in the module, 915/// create and return an llvm GlobalVariable with the specified type. If there 916/// is something in the module with the specified name, return it potentially 917/// bitcasted to the right type. 918/// 919/// If D is non-null, it specifies a decl that correspond to this. This is used 920/// to set the attributes on the global when it is first created. 921llvm::Constant * 922CodeGenModule::GetOrCreateLLVMGlobal(llvm::StringRef MangledName, 923 const llvm::PointerType *Ty, 924 const VarDecl *D) { 925 // Lookup the entry, lazily creating it if necessary. 926 llvm::GlobalValue *Entry = GetGlobalValue(MangledName); 927 if (Entry) { 928 if (WeakRefReferences.count(Entry)) { 929 if (D && !D->hasAttr<WeakAttr>()) 930 Entry->setLinkage(llvm::Function::ExternalLinkage); 931 932 WeakRefReferences.erase(Entry); 933 } 934 935 if (Entry->getType() == Ty) 936 return Entry; 937 938 // Make sure the result is of the correct type. 939 return llvm::ConstantExpr::getBitCast(Entry, Ty); 940 } 941 942 // This is the first use or definition of a mangled name. If there is a 943 // deferred decl with this name, remember that we need to emit it at the end 944 // of the file. 945 llvm::StringMap<GlobalDecl>::iterator DDI = DeferredDecls.find(MangledName); 946 if (DDI != DeferredDecls.end()) { 947 // Move the potentially referenced deferred decl to the DeferredDeclsToEmit 948 // list, and remove it from DeferredDecls (since we don't need it anymore). 949 DeferredDeclsToEmit.push_back(DDI->second); 950 DeferredDecls.erase(DDI); 951 } 952 953 llvm::GlobalVariable *GV = 954 new llvm::GlobalVariable(getModule(), Ty->getElementType(), false, 955 llvm::GlobalValue::ExternalLinkage, 956 0, MangledName, 0, 957 false, Ty->getAddressSpace()); 958 959 // Handle things which are present even on external declarations. 960 if (D) { 961 // FIXME: This code is overly simple and should be merged with other global 962 // handling. 963 GV->setConstant(DeclIsConstantGlobal(Context, D)); 964 965 // FIXME: Merge with other attribute handling code. 966 if (D->getStorageClass() == VarDecl::PrivateExtern) 967 GV->setVisibility(llvm::GlobalValue::HiddenVisibility); 968 969 if (D->hasAttr<WeakAttr>() || 970 D->hasAttr<WeakImportAttr>()) 971 GV->setLinkage(llvm::GlobalValue::ExternalWeakLinkage); 972 973 GV->setThreadLocal(D->isThreadSpecified()); 974 } 975 976 return GV; 977} 978 979 980/// GetAddrOfGlobalVar - Return the llvm::Constant for the address of the 981/// given global variable. If Ty is non-null and if the global doesn't exist, 982/// then it will be greated with the specified type instead of whatever the 983/// normal requested type would be. 984llvm::Constant *CodeGenModule::GetAddrOfGlobalVar(const VarDecl *D, 985 const llvm::Type *Ty) { 986 assert(D->hasGlobalStorage() && "Not a global variable"); 987 QualType ASTTy = D->getType(); 988 if (Ty == 0) 989 Ty = getTypes().ConvertTypeForMem(ASTTy); 990 991 const llvm::PointerType *PTy = 992 llvm::PointerType::get(Ty, ASTTy.getAddressSpace()); 993 994 llvm::StringRef MangledName = getMangledName(D); 995 return GetOrCreateLLVMGlobal(MangledName, PTy, D); 996} 997 998/// CreateRuntimeVariable - Create a new runtime global variable with the 999/// specified type and name. 1000llvm::Constant * 1001CodeGenModule::CreateRuntimeVariable(const llvm::Type *Ty, 1002 llvm::StringRef Name) { 1003 return GetOrCreateLLVMGlobal(Name, llvm::PointerType::getUnqual(Ty), 0); 1004} 1005 1006void CodeGenModule::EmitTentativeDefinition(const VarDecl *D) { 1007 assert(!D->getInit() && "Cannot emit definite definitions here!"); 1008 1009 if (MayDeferGeneration(D)) { 1010 // If we have not seen a reference to this variable yet, place it 1011 // into the deferred declarations table to be emitted if needed 1012 // later. 1013 llvm::StringRef MangledName = getMangledName(D); 1014 if (!GetGlobalValue(MangledName)) { 1015 DeferredDecls[MangledName] = D; 1016 return; 1017 } 1018 } 1019 1020 // The tentative definition is the only definition. 1021 EmitGlobalVarDefinition(D); 1022} 1023 1024void CodeGenModule::EmitVTable(CXXRecordDecl *Class, bool DefinitionRequired) { 1025 if (DefinitionRequired) 1026 getVTables().GenerateClassData(getVTableLinkage(Class), Class); 1027} 1028 1029llvm::GlobalVariable::LinkageTypes 1030CodeGenModule::getVTableLinkage(const CXXRecordDecl *RD) { 1031 if (RD->isInAnonymousNamespace() || !RD->hasLinkage()) 1032 return llvm::GlobalVariable::InternalLinkage; 1033 1034 if (const CXXMethodDecl *KeyFunction 1035 = RD->getASTContext().getKeyFunction(RD)) { 1036 // If this class has a key function, use that to determine the linkage of 1037 // the vtable. 1038 const FunctionDecl *Def = 0; 1039 if (KeyFunction->hasBody(Def)) 1040 KeyFunction = cast<CXXMethodDecl>(Def); 1041 1042 switch (KeyFunction->getTemplateSpecializationKind()) { 1043 case TSK_Undeclared: 1044 case TSK_ExplicitSpecialization: 1045 if (KeyFunction->isInlined()) 1046 return llvm::GlobalVariable::WeakODRLinkage; 1047 1048 return llvm::GlobalVariable::ExternalLinkage; 1049 1050 case TSK_ImplicitInstantiation: 1051 case TSK_ExplicitInstantiationDefinition: 1052 return llvm::GlobalVariable::WeakODRLinkage; 1053 1054 case TSK_ExplicitInstantiationDeclaration: 1055 // FIXME: Use available_externally linkage. However, this currently 1056 // breaks LLVM's build due to undefined symbols. 1057 // return llvm::GlobalVariable::AvailableExternallyLinkage; 1058 return llvm::GlobalVariable::WeakODRLinkage; 1059 } 1060 } 1061 1062 switch (RD->getTemplateSpecializationKind()) { 1063 case TSK_Undeclared: 1064 case TSK_ExplicitSpecialization: 1065 case TSK_ImplicitInstantiation: 1066 case TSK_ExplicitInstantiationDefinition: 1067 return llvm::GlobalVariable::WeakODRLinkage; 1068 1069 case TSK_ExplicitInstantiationDeclaration: 1070 // FIXME: Use available_externally linkage. However, this currently 1071 // breaks LLVM's build due to undefined symbols. 1072 // return llvm::GlobalVariable::AvailableExternallyLinkage; 1073 return llvm::GlobalVariable::WeakODRLinkage; 1074 } 1075 1076 // Silence GCC warning. 1077 return llvm::GlobalVariable::WeakODRLinkage; 1078} 1079 1080CharUnits CodeGenModule::GetTargetTypeStoreSize(const llvm::Type *Ty) const { 1081 return CharUnits::fromQuantity( 1082 TheTargetData.getTypeStoreSizeInBits(Ty) / Context.getCharWidth()); 1083} 1084 1085void CodeGenModule::EmitGlobalVarDefinition(const VarDecl *D) { 1086 llvm::Constant *Init = 0; 1087 QualType ASTTy = D->getType(); 1088 bool NonConstInit = false; 1089 1090 const Expr *InitExpr = D->getAnyInitializer(); 1091 1092 if (!InitExpr) { 1093 // This is a tentative definition; tentative definitions are 1094 // implicitly initialized with { 0 }. 1095 // 1096 // Note that tentative definitions are only emitted at the end of 1097 // a translation unit, so they should never have incomplete 1098 // type. In addition, EmitTentativeDefinition makes sure that we 1099 // never attempt to emit a tentative definition if a real one 1100 // exists. A use may still exists, however, so we still may need 1101 // to do a RAUW. 1102 assert(!ASTTy->isIncompleteType() && "Unexpected incomplete type"); 1103 Init = EmitNullConstant(D->getType()); 1104 } else { 1105 Init = EmitConstantExpr(InitExpr, D->getType()); 1106 if (!Init) { 1107 QualType T = InitExpr->getType(); 1108 if (D->getType()->isReferenceType()) 1109 T = D->getType(); 1110 1111 if (getLangOptions().CPlusPlus) { 1112 EmitCXXGlobalVarDeclInitFunc(D); 1113 Init = EmitNullConstant(T); 1114 NonConstInit = true; 1115 } else { 1116 ErrorUnsupported(D, "static initializer"); 1117 Init = llvm::UndefValue::get(getTypes().ConvertType(T)); 1118 } 1119 } else { 1120 // We don't need an initializer, so remove the entry for the delayed 1121 // initializer position (just in case this entry was delayed). 1122 if (getLangOptions().CPlusPlus) 1123 DelayedCXXInitPosition.erase(D); 1124 } 1125 } 1126 1127 const llvm::Type* InitType = Init->getType(); 1128 llvm::Constant *Entry = GetAddrOfGlobalVar(D, InitType); 1129 1130 // Strip off a bitcast if we got one back. 1131 if (llvm::ConstantExpr *CE = dyn_cast<llvm::ConstantExpr>(Entry)) { 1132 assert(CE->getOpcode() == llvm::Instruction::BitCast || 1133 // all zero index gep. 1134 CE->getOpcode() == llvm::Instruction::GetElementPtr); 1135 Entry = CE->getOperand(0); 1136 } 1137 1138 // Entry is now either a Function or GlobalVariable. 1139 llvm::GlobalVariable *GV = dyn_cast<llvm::GlobalVariable>(Entry); 1140 1141 // We have a definition after a declaration with the wrong type. 1142 // We must make a new GlobalVariable* and update everything that used OldGV 1143 // (a declaration or tentative definition) with the new GlobalVariable* 1144 // (which will be a definition). 1145 // 1146 // This happens if there is a prototype for a global (e.g. 1147 // "extern int x[];") and then a definition of a different type (e.g. 1148 // "int x[10];"). This also happens when an initializer has a different type 1149 // from the type of the global (this happens with unions). 1150 if (GV == 0 || 1151 GV->getType()->getElementType() != InitType || 1152 GV->getType()->getAddressSpace() != ASTTy.getAddressSpace()) { 1153 1154 // Move the old entry aside so that we'll create a new one. 1155 Entry->setName(llvm::StringRef()); 1156 1157 // Make a new global with the correct type, this is now guaranteed to work. 1158 GV = cast<llvm::GlobalVariable>(GetAddrOfGlobalVar(D, InitType)); 1159 1160 // Replace all uses of the old global with the new global 1161 llvm::Constant *NewPtrForOldDecl = 1162 llvm::ConstantExpr::getBitCast(GV, Entry->getType()); 1163 Entry->replaceAllUsesWith(NewPtrForOldDecl); 1164 1165 // Erase the old global, since it is no longer used. 1166 cast<llvm::GlobalValue>(Entry)->eraseFromParent(); 1167 } 1168 1169 if (const AnnotateAttr *AA = D->getAttr<AnnotateAttr>()) { 1170 SourceManager &SM = Context.getSourceManager(); 1171 AddAnnotation(EmitAnnotateAttr(GV, AA, 1172 SM.getInstantiationLineNumber(D->getLocation()))); 1173 } 1174 1175 GV->setInitializer(Init); 1176 1177 // If it is safe to mark the global 'constant', do so now. 1178 GV->setConstant(false); 1179 if (!NonConstInit && DeclIsConstantGlobal(Context, D)) 1180 GV->setConstant(true); 1181 1182 GV->setAlignment(getContext().getDeclAlign(D).getQuantity()); 1183 1184 // Set the llvm linkage type as appropriate. 1185 GVALinkage Linkage = getContext().GetGVALinkageForVariable(D); 1186 if (Linkage == GVA_Internal) 1187 GV->setLinkage(llvm::Function::InternalLinkage); 1188 else if (D->hasAttr<DLLImportAttr>()) 1189 GV->setLinkage(llvm::Function::DLLImportLinkage); 1190 else if (D->hasAttr<DLLExportAttr>()) 1191 GV->setLinkage(llvm::Function::DLLExportLinkage); 1192 else if (D->hasAttr<WeakAttr>()) { 1193 if (GV->isConstant()) 1194 GV->setLinkage(llvm::GlobalVariable::WeakODRLinkage); 1195 else 1196 GV->setLinkage(llvm::GlobalVariable::WeakAnyLinkage); 1197 } else if (Linkage == GVA_TemplateInstantiation || 1198 Linkage == GVA_ExplicitTemplateInstantiation) 1199 // FIXME: It seems like we can provide more specific linkage here 1200 // (LinkOnceODR, WeakODR). 1201 GV->setLinkage(llvm::GlobalVariable::WeakAnyLinkage); 1202 else if (!getLangOptions().CPlusPlus && !CodeGenOpts.NoCommon && 1203 !D->hasExternalStorage() && !D->getInit() && 1204 !D->getAttr<SectionAttr>()) { 1205 GV->setLinkage(llvm::GlobalVariable::CommonLinkage); 1206 // common vars aren't constant even if declared const. 1207 GV->setConstant(false); 1208 } else 1209 GV->setLinkage(llvm::GlobalVariable::ExternalLinkage); 1210 1211 SetCommonAttributes(D, GV); 1212 1213 // Emit global variable debug information. 1214 if (CGDebugInfo *DI = getDebugInfo()) { 1215 DI->setLocation(D->getLocation()); 1216 DI->EmitGlobalVariable(GV, D); 1217 } 1218} 1219 1220/// ReplaceUsesOfNonProtoTypeWithRealFunction - This function is called when we 1221/// implement a function with no prototype, e.g. "int foo() {}". If there are 1222/// existing call uses of the old function in the module, this adjusts them to 1223/// call the new function directly. 1224/// 1225/// This is not just a cleanup: the always_inline pass requires direct calls to 1226/// functions to be able to inline them. If there is a bitcast in the way, it 1227/// won't inline them. Instcombine normally deletes these calls, but it isn't 1228/// run at -O0. 1229static void ReplaceUsesOfNonProtoTypeWithRealFunction(llvm::GlobalValue *Old, 1230 llvm::Function *NewFn) { 1231 // If we're redefining a global as a function, don't transform it. 1232 llvm::Function *OldFn = dyn_cast<llvm::Function>(Old); 1233 if (OldFn == 0) return; 1234 1235 const llvm::Type *NewRetTy = NewFn->getReturnType(); 1236 llvm::SmallVector<llvm::Value*, 4> ArgList; 1237 1238 for (llvm::Value::use_iterator UI = OldFn->use_begin(), E = OldFn->use_end(); 1239 UI != E; ) { 1240 // TODO: Do invokes ever occur in C code? If so, we should handle them too. 1241 llvm::Value::use_iterator I = UI++; // Increment before the CI is erased. 1242 llvm::CallInst *CI = dyn_cast<llvm::CallInst>(*I); 1243 if (!CI) continue; // FIXME: when we allow Invoke, just do CallSite CS(*I) 1244 llvm::CallSite CS(CI); 1245 if (!CI || !CS.isCallee(I)) continue; 1246 1247 // If the return types don't match exactly, and if the call isn't dead, then 1248 // we can't transform this call. 1249 if (CI->getType() != NewRetTy && !CI->use_empty()) 1250 continue; 1251 1252 // If the function was passed too few arguments, don't transform. If extra 1253 // arguments were passed, we silently drop them. If any of the types 1254 // mismatch, we don't transform. 1255 unsigned ArgNo = 0; 1256 bool DontTransform = false; 1257 for (llvm::Function::arg_iterator AI = NewFn->arg_begin(), 1258 E = NewFn->arg_end(); AI != E; ++AI, ++ArgNo) { 1259 if (CS.arg_size() == ArgNo || 1260 CS.getArgument(ArgNo)->getType() != AI->getType()) { 1261 DontTransform = true; 1262 break; 1263 } 1264 } 1265 if (DontTransform) 1266 continue; 1267 1268 // Okay, we can transform this. Create the new call instruction and copy 1269 // over the required information. 1270 ArgList.append(CS.arg_begin(), CS.arg_begin() + ArgNo); 1271 llvm::CallInst *NewCall = llvm::CallInst::Create(NewFn, ArgList.begin(), 1272 ArgList.end(), "", CI); 1273 ArgList.clear(); 1274 if (!NewCall->getType()->isVoidTy()) 1275 NewCall->takeName(CI); 1276 NewCall->setAttributes(CI->getAttributes()); 1277 NewCall->setCallingConv(CI->getCallingConv()); 1278 1279 // Finally, remove the old call, replacing any uses with the new one. 1280 if (!CI->use_empty()) 1281 CI->replaceAllUsesWith(NewCall); 1282 1283 // Copy debug location attached to CI. 1284 if (!CI->getDebugLoc().isUnknown()) 1285 NewCall->setDebugLoc(CI->getDebugLoc()); 1286 CI->eraseFromParent(); 1287 } 1288} 1289 1290 1291void CodeGenModule::EmitGlobalFunctionDefinition(GlobalDecl GD) { 1292 const FunctionDecl *D = cast<FunctionDecl>(GD.getDecl()); 1293 const llvm::FunctionType *Ty = getTypes().GetFunctionType(GD); 1294 getMangleContext().mangleInitDiscriminator(); 1295 // Get or create the prototype for the function. 1296 llvm::Constant *Entry = GetAddrOfFunction(GD, Ty); 1297 1298 // Strip off a bitcast if we got one back. 1299 if (llvm::ConstantExpr *CE = dyn_cast<llvm::ConstantExpr>(Entry)) { 1300 assert(CE->getOpcode() == llvm::Instruction::BitCast); 1301 Entry = CE->getOperand(0); 1302 } 1303 1304 1305 if (cast<llvm::GlobalValue>(Entry)->getType()->getElementType() != Ty) { 1306 llvm::GlobalValue *OldFn = cast<llvm::GlobalValue>(Entry); 1307 1308 // If the types mismatch then we have to rewrite the definition. 1309 assert(OldFn->isDeclaration() && 1310 "Shouldn't replace non-declaration"); 1311 1312 // F is the Function* for the one with the wrong type, we must make a new 1313 // Function* and update everything that used F (a declaration) with the new 1314 // Function* (which will be a definition). 1315 // 1316 // This happens if there is a prototype for a function 1317 // (e.g. "int f()") and then a definition of a different type 1318 // (e.g. "int f(int x)"). Move the old function aside so that it 1319 // doesn't interfere with GetAddrOfFunction. 1320 OldFn->setName(llvm::StringRef()); 1321 llvm::Function *NewFn = cast<llvm::Function>(GetAddrOfFunction(GD, Ty)); 1322 1323 // If this is an implementation of a function without a prototype, try to 1324 // replace any existing uses of the function (which may be calls) with uses 1325 // of the new function 1326 if (D->getType()->isFunctionNoProtoType()) { 1327 ReplaceUsesOfNonProtoTypeWithRealFunction(OldFn, NewFn); 1328 OldFn->removeDeadConstantUsers(); 1329 } 1330 1331 // Replace uses of F with the Function we will endow with a body. 1332 if (!Entry->use_empty()) { 1333 llvm::Constant *NewPtrForOldDecl = 1334 llvm::ConstantExpr::getBitCast(NewFn, Entry->getType()); 1335 Entry->replaceAllUsesWith(NewPtrForOldDecl); 1336 } 1337 1338 // Ok, delete the old function now, which is dead. 1339 OldFn->eraseFromParent(); 1340 1341 Entry = NewFn; 1342 } 1343 1344 llvm::Function *Fn = cast<llvm::Function>(Entry); 1345 setFunctionLinkage(D, Fn); 1346 1347 CodeGenFunction(*this).GenerateCode(D, Fn); 1348 1349 SetFunctionDefinitionAttributes(D, Fn); 1350 SetLLVMFunctionAttributesForDefinition(D, Fn); 1351 1352 if (const ConstructorAttr *CA = D->getAttr<ConstructorAttr>()) 1353 AddGlobalCtor(Fn, CA->getPriority()); 1354 if (const DestructorAttr *DA = D->getAttr<DestructorAttr>()) 1355 AddGlobalDtor(Fn, DA->getPriority()); 1356} 1357 1358void CodeGenModule::EmitAliasDefinition(GlobalDecl GD) { 1359 const ValueDecl *D = cast<ValueDecl>(GD.getDecl()); 1360 const AliasAttr *AA = D->getAttr<AliasAttr>(); 1361 assert(AA && "Not an alias?"); 1362 1363 llvm::StringRef MangledName = getMangledName(GD); 1364 1365 // If there is a definition in the module, then it wins over the alias. 1366 // This is dubious, but allow it to be safe. Just ignore the alias. 1367 llvm::GlobalValue *Entry = GetGlobalValue(MangledName); 1368 if (Entry && !Entry->isDeclaration()) 1369 return; 1370 1371 const llvm::Type *DeclTy = getTypes().ConvertTypeForMem(D->getType()); 1372 1373 // Create a reference to the named value. This ensures that it is emitted 1374 // if a deferred decl. 1375 llvm::Constant *Aliasee; 1376 if (isa<llvm::FunctionType>(DeclTy)) 1377 Aliasee = GetOrCreateLLVMFunction(AA->getAliasee(), DeclTy, GlobalDecl()); 1378 else 1379 Aliasee = GetOrCreateLLVMGlobal(AA->getAliasee(), 1380 llvm::PointerType::getUnqual(DeclTy), 0); 1381 1382 // Create the new alias itself, but don't set a name yet. 1383 llvm::GlobalValue *GA = 1384 new llvm::GlobalAlias(Aliasee->getType(), 1385 llvm::Function::ExternalLinkage, 1386 "", Aliasee, &getModule()); 1387 1388 if (Entry) { 1389 assert(Entry->isDeclaration()); 1390 1391 // If there is a declaration in the module, then we had an extern followed 1392 // by the alias, as in: 1393 // extern int test6(); 1394 // ... 1395 // int test6() __attribute__((alias("test7"))); 1396 // 1397 // Remove it and replace uses of it with the alias. 1398 GA->takeName(Entry); 1399 1400 Entry->replaceAllUsesWith(llvm::ConstantExpr::getBitCast(GA, 1401 Entry->getType())); 1402 Entry->eraseFromParent(); 1403 } else { 1404 GA->setName(MangledName); 1405 } 1406 1407 // Set attributes which are particular to an alias; this is a 1408 // specialization of the attributes which may be set on a global 1409 // variable/function. 1410 if (D->hasAttr<DLLExportAttr>()) { 1411 if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) { 1412 // The dllexport attribute is ignored for undefined symbols. 1413 if (FD->hasBody()) 1414 GA->setLinkage(llvm::Function::DLLExportLinkage); 1415 } else { 1416 GA->setLinkage(llvm::Function::DLLExportLinkage); 1417 } 1418 } else if (D->hasAttr<WeakAttr>() || 1419 D->hasAttr<WeakRefAttr>() || 1420 D->hasAttr<WeakImportAttr>()) { 1421 GA->setLinkage(llvm::Function::WeakAnyLinkage); 1422 } 1423 1424 SetCommonAttributes(D, GA); 1425} 1426 1427/// getBuiltinLibFunction - Given a builtin id for a function like 1428/// "__builtin_fabsf", return a Function* for "fabsf". 1429llvm::Value *CodeGenModule::getBuiltinLibFunction(const FunctionDecl *FD, 1430 unsigned BuiltinID) { 1431 assert((Context.BuiltinInfo.isLibFunction(BuiltinID) || 1432 Context.BuiltinInfo.isPredefinedLibFunction(BuiltinID)) && 1433 "isn't a lib fn"); 1434 1435 // Get the name, skip over the __builtin_ prefix (if necessary). 1436 const char *Name = Context.BuiltinInfo.GetName(BuiltinID); 1437 if (Context.BuiltinInfo.isLibFunction(BuiltinID)) 1438 Name += 10; 1439 1440 const llvm::FunctionType *Ty = 1441 cast<llvm::FunctionType>(getTypes().ConvertType(FD->getType())); 1442 1443 return GetOrCreateLLVMFunction(Name, Ty, GlobalDecl(FD)); 1444} 1445 1446llvm::Function *CodeGenModule::getIntrinsic(unsigned IID,const llvm::Type **Tys, 1447 unsigned NumTys) { 1448 return llvm::Intrinsic::getDeclaration(&getModule(), 1449 (llvm::Intrinsic::ID)IID, Tys, NumTys); 1450} 1451 1452 1453llvm::Function *CodeGenModule::getMemCpyFn(const llvm::Type *DestType, 1454 const llvm::Type *SrcType, 1455 const llvm::Type *SizeType) { 1456 const llvm::Type *ArgTypes[3] = {DestType, SrcType, SizeType }; 1457 return getIntrinsic(llvm::Intrinsic::memcpy, ArgTypes, 3); 1458} 1459 1460llvm::Function *CodeGenModule::getMemMoveFn(const llvm::Type *DestType, 1461 const llvm::Type *SrcType, 1462 const llvm::Type *SizeType) { 1463 const llvm::Type *ArgTypes[3] = {DestType, SrcType, SizeType }; 1464 return getIntrinsic(llvm::Intrinsic::memmove, ArgTypes, 3); 1465} 1466 1467llvm::Function *CodeGenModule::getMemSetFn(const llvm::Type *DestType, 1468 const llvm::Type *SizeType) { 1469 const llvm::Type *ArgTypes[2] = { DestType, SizeType }; 1470 return getIntrinsic(llvm::Intrinsic::memset, ArgTypes, 2); 1471} 1472 1473static llvm::StringMapEntry<llvm::Constant*> & 1474GetConstantCFStringEntry(llvm::StringMap<llvm::Constant*> &Map, 1475 const StringLiteral *Literal, 1476 bool TargetIsLSB, 1477 bool &IsUTF16, 1478 unsigned &StringLength) { 1479 unsigned NumBytes = Literal->getByteLength(); 1480 1481 // Check for simple case. 1482 if (!Literal->containsNonAsciiOrNull()) { 1483 StringLength = NumBytes; 1484 return Map.GetOrCreateValue(llvm::StringRef(Literal->getStrData(), 1485 StringLength)); 1486 } 1487 1488 // Otherwise, convert the UTF8 literals into a byte string. 1489 llvm::SmallVector<UTF16, 128> ToBuf(NumBytes); 1490 const UTF8 *FromPtr = (UTF8 *)Literal->getStrData(); 1491 UTF16 *ToPtr = &ToBuf[0]; 1492 1493 ConversionResult Result = ConvertUTF8toUTF16(&FromPtr, FromPtr + NumBytes, 1494 &ToPtr, ToPtr + NumBytes, 1495 strictConversion); 1496 1497 // Check for conversion failure. 1498 if (Result != conversionOK) { 1499 // FIXME: Have Sema::CheckObjCString() validate the UTF-8 string and remove 1500 // this duplicate code. 1501 assert(Result == sourceIllegal && "UTF-8 to UTF-16 conversion failed"); 1502 StringLength = NumBytes; 1503 return Map.GetOrCreateValue(llvm::StringRef(Literal->getStrData(), 1504 StringLength)); 1505 } 1506 1507 // ConvertUTF8toUTF16 returns the length in ToPtr. 1508 StringLength = ToPtr - &ToBuf[0]; 1509 1510 // Render the UTF-16 string into a byte array and convert to the target byte 1511 // order. 1512 // 1513 // FIXME: This isn't something we should need to do here. 1514 llvm::SmallString<128> AsBytes; 1515 AsBytes.reserve(StringLength * 2); 1516 for (unsigned i = 0; i != StringLength; ++i) { 1517 unsigned short Val = ToBuf[i]; 1518 if (TargetIsLSB) { 1519 AsBytes.push_back(Val & 0xFF); 1520 AsBytes.push_back(Val >> 8); 1521 } else { 1522 AsBytes.push_back(Val >> 8); 1523 AsBytes.push_back(Val & 0xFF); 1524 } 1525 } 1526 // Append one extra null character, the second is automatically added by our 1527 // caller. 1528 AsBytes.push_back(0); 1529 1530 IsUTF16 = true; 1531 return Map.GetOrCreateValue(llvm::StringRef(AsBytes.data(), AsBytes.size())); 1532} 1533 1534llvm::Constant * 1535CodeGenModule::GetAddrOfConstantCFString(const StringLiteral *Literal) { 1536 unsigned StringLength = 0; 1537 bool isUTF16 = false; 1538 llvm::StringMapEntry<llvm::Constant*> &Entry = 1539 GetConstantCFStringEntry(CFConstantStringMap, Literal, 1540 getTargetData().isLittleEndian(), 1541 isUTF16, StringLength); 1542 1543 if (llvm::Constant *C = Entry.getValue()) 1544 return C; 1545 1546 llvm::Constant *Zero = 1547 llvm::Constant::getNullValue(llvm::Type::getInt32Ty(VMContext)); 1548 llvm::Constant *Zeros[] = { Zero, Zero }; 1549 1550 // If we don't already have it, get __CFConstantStringClassReference. 1551 if (!CFConstantStringClassRef) { 1552 const llvm::Type *Ty = getTypes().ConvertType(getContext().IntTy); 1553 Ty = llvm::ArrayType::get(Ty, 0); 1554 llvm::Constant *GV = CreateRuntimeVariable(Ty, 1555 "__CFConstantStringClassReference"); 1556 // Decay array -> ptr 1557 CFConstantStringClassRef = 1558 llvm::ConstantExpr::getGetElementPtr(GV, Zeros, 2); 1559 } 1560 1561 QualType CFTy = getContext().getCFConstantStringType(); 1562 1563 const llvm::StructType *STy = 1564 cast<llvm::StructType>(getTypes().ConvertType(CFTy)); 1565 1566 std::vector<llvm::Constant*> Fields(4); 1567 1568 // Class pointer. 1569 Fields[0] = CFConstantStringClassRef; 1570 1571 // Flags. 1572 const llvm::Type *Ty = getTypes().ConvertType(getContext().UnsignedIntTy); 1573 Fields[1] = isUTF16 ? llvm::ConstantInt::get(Ty, 0x07d0) : 1574 llvm::ConstantInt::get(Ty, 0x07C8); 1575 1576 // String pointer. 1577 llvm::Constant *C = llvm::ConstantArray::get(VMContext, Entry.getKey().str()); 1578 1579 llvm::GlobalValue::LinkageTypes Linkage; 1580 bool isConstant; 1581 if (isUTF16) { 1582 // FIXME: why do utf strings get "_" labels instead of "L" labels? 1583 Linkage = llvm::GlobalValue::InternalLinkage; 1584 // Note: -fwritable-strings doesn't make unicode CFStrings writable, but 1585 // does make plain ascii ones writable. 1586 isConstant = true; 1587 } else { 1588 Linkage = llvm::GlobalValue::PrivateLinkage; 1589 isConstant = !Features.WritableStrings; 1590 } 1591 1592 llvm::GlobalVariable *GV = 1593 new llvm::GlobalVariable(getModule(), C->getType(), isConstant, Linkage, C, 1594 ".str"); 1595 if (isUTF16) { 1596 CharUnits Align = getContext().getTypeAlignInChars(getContext().ShortTy); 1597 GV->setAlignment(Align.getQuantity()); 1598 } 1599 Fields[2] = llvm::ConstantExpr::getGetElementPtr(GV, Zeros, 2); 1600 1601 // String length. 1602 Ty = getTypes().ConvertType(getContext().LongTy); 1603 Fields[3] = llvm::ConstantInt::get(Ty, StringLength); 1604 1605 // The struct. 1606 C = llvm::ConstantStruct::get(STy, Fields); 1607 GV = new llvm::GlobalVariable(getModule(), C->getType(), true, 1608 llvm::GlobalVariable::PrivateLinkage, C, 1609 "_unnamed_cfstring_"); 1610 if (const char *Sect = getContext().Target.getCFStringSection()) 1611 GV->setSection(Sect); 1612 Entry.setValue(GV); 1613 1614 return GV; 1615} 1616 1617llvm::Constant * 1618CodeGenModule::GetAddrOfConstantNSString(const StringLiteral *Literal) { 1619 unsigned StringLength = 0; 1620 bool isUTF16 = false; 1621 llvm::StringMapEntry<llvm::Constant*> &Entry = 1622 GetConstantCFStringEntry(CFConstantStringMap, Literal, 1623 getTargetData().isLittleEndian(), 1624 isUTF16, StringLength); 1625 1626 if (llvm::Constant *C = Entry.getValue()) 1627 return C; 1628 1629 llvm::Constant *Zero = 1630 llvm::Constant::getNullValue(llvm::Type::getInt32Ty(VMContext)); 1631 llvm::Constant *Zeros[] = { Zero, Zero }; 1632 1633 // If we don't already have it, get _NSConstantStringClassReference. 1634 if (!NSConstantStringClassRef) { 1635 const llvm::Type *Ty = getTypes().ConvertType(getContext().IntTy); 1636 Ty = llvm::ArrayType::get(Ty, 0); 1637 llvm::Constant *GV = CreateRuntimeVariable(Ty, 1638 Features.ObjCNonFragileABI ? 1639 "OBJC_CLASS_$_NSConstantString" : 1640 "_NSConstantStringClassReference"); 1641 // Decay array -> ptr 1642 NSConstantStringClassRef = 1643 llvm::ConstantExpr::getGetElementPtr(GV, Zeros, 2); 1644 } 1645 1646 QualType NSTy = getContext().getNSConstantStringType(); 1647 1648 const llvm::StructType *STy = 1649 cast<llvm::StructType>(getTypes().ConvertType(NSTy)); 1650 1651 std::vector<llvm::Constant*> Fields(3); 1652 1653 // Class pointer. 1654 Fields[0] = NSConstantStringClassRef; 1655 1656 // String pointer. 1657 llvm::Constant *C = llvm::ConstantArray::get(VMContext, Entry.getKey().str()); 1658 1659 llvm::GlobalValue::LinkageTypes Linkage; 1660 bool isConstant; 1661 if (isUTF16) { 1662 // FIXME: why do utf strings get "_" labels instead of "L" labels? 1663 Linkage = llvm::GlobalValue::InternalLinkage; 1664 // Note: -fwritable-strings doesn't make unicode NSStrings writable, but 1665 // does make plain ascii ones writable. 1666 isConstant = true; 1667 } else { 1668 Linkage = llvm::GlobalValue::PrivateLinkage; 1669 isConstant = !Features.WritableStrings; 1670 } 1671 1672 llvm::GlobalVariable *GV = 1673 new llvm::GlobalVariable(getModule(), C->getType(), isConstant, Linkage, C, 1674 ".str"); 1675 if (isUTF16) { 1676 CharUnits Align = getContext().getTypeAlignInChars(getContext().ShortTy); 1677 GV->setAlignment(Align.getQuantity()); 1678 } 1679 Fields[1] = llvm::ConstantExpr::getGetElementPtr(GV, Zeros, 2); 1680 1681 // String length. 1682 const llvm::Type *Ty = getTypes().ConvertType(getContext().UnsignedIntTy); 1683 Fields[2] = llvm::ConstantInt::get(Ty, StringLength); 1684 1685 // The struct. 1686 C = llvm::ConstantStruct::get(STy, Fields); 1687 GV = new llvm::GlobalVariable(getModule(), C->getType(), true, 1688 llvm::GlobalVariable::PrivateLinkage, C, 1689 "_unnamed_nsstring_"); 1690 // FIXME. Fix section. 1691 if (const char *Sect = 1692 Features.ObjCNonFragileABI 1693 ? getContext().Target.getNSStringNonFragileABISection() 1694 : getContext().Target.getNSStringSection()) 1695 GV->setSection(Sect); 1696 Entry.setValue(GV); 1697 1698 return GV; 1699} 1700 1701/// GetStringForStringLiteral - Return the appropriate bytes for a 1702/// string literal, properly padded to match the literal type. 1703std::string CodeGenModule::GetStringForStringLiteral(const StringLiteral *E) { 1704 const char *StrData = E->getStrData(); 1705 unsigned Len = E->getByteLength(); 1706 1707 const ConstantArrayType *CAT = 1708 getContext().getAsConstantArrayType(E->getType()); 1709 assert(CAT && "String isn't pointer or array!"); 1710 1711 // Resize the string to the right size. 1712 std::string Str(StrData, StrData+Len); 1713 uint64_t RealLen = CAT->getSize().getZExtValue(); 1714 1715 if (E->isWide()) 1716 RealLen *= getContext().Target.getWCharWidth()/8; 1717 1718 Str.resize(RealLen, '\0'); 1719 1720 return Str; 1721} 1722 1723/// GetAddrOfConstantStringFromLiteral - Return a pointer to a 1724/// constant array for the given string literal. 1725llvm::Constant * 1726CodeGenModule::GetAddrOfConstantStringFromLiteral(const StringLiteral *S) { 1727 // FIXME: This can be more efficient. 1728 // FIXME: We shouldn't need to bitcast the constant in the wide string case. 1729 llvm::Constant *C = GetAddrOfConstantString(GetStringForStringLiteral(S)); 1730 if (S->isWide()) { 1731 llvm::Type *DestTy = 1732 llvm::PointerType::getUnqual(getTypes().ConvertType(S->getType())); 1733 C = llvm::ConstantExpr::getBitCast(C, DestTy); 1734 } 1735 return C; 1736} 1737 1738/// GetAddrOfConstantStringFromObjCEncode - Return a pointer to a constant 1739/// array for the given ObjCEncodeExpr node. 1740llvm::Constant * 1741CodeGenModule::GetAddrOfConstantStringFromObjCEncode(const ObjCEncodeExpr *E) { 1742 std::string Str; 1743 getContext().getObjCEncodingForType(E->getEncodedType(), Str); 1744 1745 return GetAddrOfConstantCString(Str); 1746} 1747 1748 1749/// GenerateWritableString -- Creates storage for a string literal. 1750static llvm::Constant *GenerateStringLiteral(const std::string &str, 1751 bool constant, 1752 CodeGenModule &CGM, 1753 const char *GlobalName) { 1754 // Create Constant for this string literal. Don't add a '\0'. 1755 llvm::Constant *C = 1756 llvm::ConstantArray::get(CGM.getLLVMContext(), str, false); 1757 1758 // Create a global variable for this string 1759 return new llvm::GlobalVariable(CGM.getModule(), C->getType(), constant, 1760 llvm::GlobalValue::PrivateLinkage, 1761 C, GlobalName); 1762} 1763 1764/// GetAddrOfConstantString - Returns a pointer to a character array 1765/// containing the literal. This contents are exactly that of the 1766/// given string, i.e. it will not be null terminated automatically; 1767/// see GetAddrOfConstantCString. Note that whether the result is 1768/// actually a pointer to an LLVM constant depends on 1769/// Feature.WriteableStrings. 1770/// 1771/// The result has pointer to array type. 1772llvm::Constant *CodeGenModule::GetAddrOfConstantString(const std::string &str, 1773 const char *GlobalName) { 1774 bool IsConstant = !Features.WritableStrings; 1775 1776 // Get the default prefix if a name wasn't specified. 1777 if (!GlobalName) 1778 GlobalName = ".str"; 1779 1780 // Don't share any string literals if strings aren't constant. 1781 if (!IsConstant) 1782 return GenerateStringLiteral(str, false, *this, GlobalName); 1783 1784 llvm::StringMapEntry<llvm::Constant *> &Entry = 1785 ConstantStringMap.GetOrCreateValue(&str[0], &str[str.length()]); 1786 1787 if (Entry.getValue()) 1788 return Entry.getValue(); 1789 1790 // Create a global variable for this. 1791 llvm::Constant *C = GenerateStringLiteral(str, true, *this, GlobalName); 1792 Entry.setValue(C); 1793 return C; 1794} 1795 1796/// GetAddrOfConstantCString - Returns a pointer to a character 1797/// array containing the literal and a terminating '\-' 1798/// character. The result has pointer to array type. 1799llvm::Constant *CodeGenModule::GetAddrOfConstantCString(const std::string &str, 1800 const char *GlobalName){ 1801 return GetAddrOfConstantString(str + '\0', GlobalName); 1802} 1803 1804/// EmitObjCPropertyImplementations - Emit information for synthesized 1805/// properties for an implementation. 1806void CodeGenModule::EmitObjCPropertyImplementations(const 1807 ObjCImplementationDecl *D) { 1808 for (ObjCImplementationDecl::propimpl_iterator 1809 i = D->propimpl_begin(), e = D->propimpl_end(); i != e; ++i) { 1810 ObjCPropertyImplDecl *PID = *i; 1811 1812 // Dynamic is just for type-checking. 1813 if (PID->getPropertyImplementation() == ObjCPropertyImplDecl::Synthesize) { 1814 ObjCPropertyDecl *PD = PID->getPropertyDecl(); 1815 1816 // Determine which methods need to be implemented, some may have 1817 // been overridden. Note that ::isSynthesized is not the method 1818 // we want, that just indicates if the decl came from a 1819 // property. What we want to know is if the method is defined in 1820 // this implementation. 1821 if (!D->getInstanceMethod(PD->getGetterName())) 1822 CodeGenFunction(*this).GenerateObjCGetter( 1823 const_cast<ObjCImplementationDecl *>(D), PID); 1824 if (!PD->isReadOnly() && 1825 !D->getInstanceMethod(PD->getSetterName())) 1826 CodeGenFunction(*this).GenerateObjCSetter( 1827 const_cast<ObjCImplementationDecl *>(D), PID); 1828 } 1829 } 1830} 1831 1832/// EmitObjCIvarInitializations - Emit information for ivar initialization 1833/// for an implementation. 1834void CodeGenModule::EmitObjCIvarInitializations(ObjCImplementationDecl *D) { 1835 if (!Features.NeXTRuntime || D->getNumIvarInitializers() == 0) 1836 return; 1837 DeclContext* DC = const_cast<DeclContext*>(dyn_cast<DeclContext>(D)); 1838 assert(DC && "EmitObjCIvarInitializations - null DeclContext"); 1839 IdentifierInfo *II = &getContext().Idents.get(".cxx_destruct"); 1840 Selector cxxSelector = getContext().Selectors.getSelector(0, &II); 1841 ObjCMethodDecl *DTORMethod = ObjCMethodDecl::Create(getContext(), 1842 D->getLocation(), 1843 D->getLocation(), cxxSelector, 1844 getContext().VoidTy, 0, 1845 DC, true, false, true, false, 1846 ObjCMethodDecl::Required); 1847 D->addInstanceMethod(DTORMethod); 1848 CodeGenFunction(*this).GenerateObjCCtorDtorMethod(D, DTORMethod, false); 1849 1850 II = &getContext().Idents.get(".cxx_construct"); 1851 cxxSelector = getContext().Selectors.getSelector(0, &II); 1852 // The constructor returns 'self'. 1853 ObjCMethodDecl *CTORMethod = ObjCMethodDecl::Create(getContext(), 1854 D->getLocation(), 1855 D->getLocation(), cxxSelector, 1856 getContext().getObjCIdType(), 0, 1857 DC, true, false, true, false, 1858 ObjCMethodDecl::Required); 1859 D->addInstanceMethod(CTORMethod); 1860 CodeGenFunction(*this).GenerateObjCCtorDtorMethod(D, CTORMethod, true); 1861 1862 1863} 1864 1865/// EmitNamespace - Emit all declarations in a namespace. 1866void CodeGenModule::EmitNamespace(const NamespaceDecl *ND) { 1867 for (RecordDecl::decl_iterator I = ND->decls_begin(), E = ND->decls_end(); 1868 I != E; ++I) 1869 EmitTopLevelDecl(*I); 1870} 1871 1872// EmitLinkageSpec - Emit all declarations in a linkage spec. 1873void CodeGenModule::EmitLinkageSpec(const LinkageSpecDecl *LSD) { 1874 if (LSD->getLanguage() != LinkageSpecDecl::lang_c && 1875 LSD->getLanguage() != LinkageSpecDecl::lang_cxx) { 1876 ErrorUnsupported(LSD, "linkage spec"); 1877 return; 1878 } 1879 1880 for (RecordDecl::decl_iterator I = LSD->decls_begin(), E = LSD->decls_end(); 1881 I != E; ++I) 1882 EmitTopLevelDecl(*I); 1883} 1884 1885/// EmitTopLevelDecl - Emit code for a single top level declaration. 1886void CodeGenModule::EmitTopLevelDecl(Decl *D) { 1887 // If an error has occurred, stop code generation, but continue 1888 // parsing and semantic analysis (to ensure all warnings and errors 1889 // are emitted). 1890 if (Diags.hasErrorOccurred()) 1891 return; 1892 1893 // Ignore dependent declarations. 1894 if (D->getDeclContext() && D->getDeclContext()->isDependentContext()) 1895 return; 1896 1897 switch (D->getKind()) { 1898 case Decl::CXXConversion: 1899 case Decl::CXXMethod: 1900 case Decl::Function: 1901 // Skip function templates 1902 if (cast<FunctionDecl>(D)->getDescribedFunctionTemplate()) 1903 return; 1904 1905 EmitGlobal(cast<FunctionDecl>(D)); 1906 break; 1907 1908 case Decl::Var: 1909 EmitGlobal(cast<VarDecl>(D)); 1910 break; 1911 1912 // C++ Decls 1913 case Decl::Namespace: 1914 EmitNamespace(cast<NamespaceDecl>(D)); 1915 break; 1916 // No code generation needed. 1917 case Decl::UsingShadow: 1918 case Decl::Using: 1919 case Decl::UsingDirective: 1920 case Decl::ClassTemplate: 1921 case Decl::FunctionTemplate: 1922 case Decl::NamespaceAlias: 1923 break; 1924 case Decl::CXXConstructor: 1925 // Skip function templates 1926 if (cast<FunctionDecl>(D)->getDescribedFunctionTemplate()) 1927 return; 1928 1929 EmitCXXConstructors(cast<CXXConstructorDecl>(D)); 1930 break; 1931 case Decl::CXXDestructor: 1932 EmitCXXDestructors(cast<CXXDestructorDecl>(D)); 1933 break; 1934 1935 case Decl::StaticAssert: 1936 // Nothing to do. 1937 break; 1938 1939 // Objective-C Decls 1940 1941 // Forward declarations, no (immediate) code generation. 1942 case Decl::ObjCClass: 1943 case Decl::ObjCForwardProtocol: 1944 case Decl::ObjCCategory: 1945 case Decl::ObjCInterface: 1946 break; 1947 1948 case Decl::ObjCProtocol: 1949 Runtime->GenerateProtocol(cast<ObjCProtocolDecl>(D)); 1950 break; 1951 1952 case Decl::ObjCCategoryImpl: 1953 // Categories have properties but don't support synthesize so we 1954 // can ignore them here. 1955 Runtime->GenerateCategory(cast<ObjCCategoryImplDecl>(D)); 1956 break; 1957 1958 case Decl::ObjCImplementation: { 1959 ObjCImplementationDecl *OMD = cast<ObjCImplementationDecl>(D); 1960 EmitObjCPropertyImplementations(OMD); 1961 EmitObjCIvarInitializations(OMD); 1962 Runtime->GenerateClass(OMD); 1963 break; 1964 } 1965 case Decl::ObjCMethod: { 1966 ObjCMethodDecl *OMD = cast<ObjCMethodDecl>(D); 1967 // If this is not a prototype, emit the body. 1968 if (OMD->getBody()) 1969 CodeGenFunction(*this).GenerateObjCMethod(OMD); 1970 break; 1971 } 1972 case Decl::ObjCCompatibleAlias: 1973 // compatibility-alias is a directive and has no code gen. 1974 break; 1975 1976 case Decl::LinkageSpec: 1977 EmitLinkageSpec(cast<LinkageSpecDecl>(D)); 1978 break; 1979 1980 case Decl::FileScopeAsm: { 1981 FileScopeAsmDecl *AD = cast<FileScopeAsmDecl>(D); 1982 llvm::StringRef AsmString = AD->getAsmString()->getString(); 1983 1984 const std::string &S = getModule().getModuleInlineAsm(); 1985 if (S.empty()) 1986 getModule().setModuleInlineAsm(AsmString); 1987 else 1988 getModule().setModuleInlineAsm(S + '\n' + AsmString.str()); 1989 break; 1990 } 1991 1992 default: 1993 // Make sure we handled everything we should, every other kind is a 1994 // non-top-level decl. FIXME: Would be nice to have an isTopLevelDeclKind 1995 // function. Need to recode Decl::Kind to do that easily. 1996 assert(isa<TypeDecl>(D) && "Unsupported decl kind"); 1997 } 1998} 1999 2000/// Turns the given pointer into a constant. 2001static llvm::Constant *GetPointerConstant(llvm::LLVMContext &Context, 2002 const void *Ptr) { 2003 uintptr_t PtrInt = reinterpret_cast<uintptr_t>(Ptr); 2004 const llvm::Type *i64 = llvm::Type::getInt64Ty(Context); 2005 return llvm::ConstantInt::get(i64, PtrInt); 2006} 2007 2008static void EmitGlobalDeclMetadata(CodeGenModule &CGM, 2009 llvm::NamedMDNode *&GlobalMetadata, 2010 GlobalDecl D, 2011 llvm::GlobalValue *Addr) { 2012 if (!GlobalMetadata) 2013 GlobalMetadata = 2014 CGM.getModule().getOrInsertNamedMetadata("clang.global.decl.ptrs"); 2015 2016 // TODO: should we report variant information for ctors/dtors? 2017 llvm::Value *Ops[] = { 2018 Addr, 2019 GetPointerConstant(CGM.getLLVMContext(), D.getDecl()) 2020 }; 2021 GlobalMetadata->addOperand(llvm::MDNode::get(CGM.getLLVMContext(), Ops, 2)); 2022} 2023 2024/// Emits metadata nodes associating all the global values in the 2025/// current module with the Decls they came from. This is useful for 2026/// projects using IR gen as a subroutine. 2027/// 2028/// Since there's currently no way to associate an MDNode directly 2029/// with an llvm::GlobalValue, we create a global named metadata 2030/// with the name 'clang.global.decl.ptrs'. 2031void CodeGenModule::EmitDeclMetadata() { 2032 llvm::NamedMDNode *GlobalMetadata = 0; 2033 2034 // StaticLocalDeclMap 2035 for (llvm::DenseMap<GlobalDecl,llvm::StringRef>::iterator 2036 I = MangledDeclNames.begin(), E = MangledDeclNames.end(); 2037 I != E; ++I) { 2038 llvm::GlobalValue *Addr = getModule().getNamedValue(I->second); 2039 EmitGlobalDeclMetadata(*this, GlobalMetadata, I->first, Addr); 2040 } 2041} 2042 2043/// Emits metadata nodes for all the local variables in the current 2044/// function. 2045void CodeGenFunction::EmitDeclMetadata() { 2046 if (LocalDeclMap.empty()) return; 2047 2048 llvm::LLVMContext &Context = getLLVMContext(); 2049 2050 // Find the unique metadata ID for this name. 2051 unsigned DeclPtrKind = Context.getMDKindID("clang.decl.ptr"); 2052 2053 llvm::NamedMDNode *GlobalMetadata = 0; 2054 2055 for (llvm::DenseMap<const Decl*, llvm::Value*>::iterator 2056 I = LocalDeclMap.begin(), E = LocalDeclMap.end(); I != E; ++I) { 2057 const Decl *D = I->first; 2058 llvm::Value *Addr = I->second; 2059 2060 if (llvm::AllocaInst *Alloca = dyn_cast<llvm::AllocaInst>(Addr)) { 2061 llvm::Value *DAddr = GetPointerConstant(getLLVMContext(), D); 2062 Alloca->setMetadata(DeclPtrKind, llvm::MDNode::get(Context, &DAddr, 1)); 2063 } else if (llvm::GlobalValue *GV = dyn_cast<llvm::GlobalValue>(Addr)) { 2064 GlobalDecl GD = GlobalDecl(cast<VarDecl>(D)); 2065 EmitGlobalDeclMetadata(CGM, GlobalMetadata, GD, GV); 2066 } 2067 } 2068} 2069 2070///@name Custom Runtime Function Interfaces 2071///@{ 2072// 2073// FIXME: These can be eliminated once we can have clients just get the required 2074// AST nodes from the builtin tables. 2075 2076llvm::Constant *CodeGenModule::getBlockObjectDispose() { 2077 if (BlockObjectDispose) 2078 return BlockObjectDispose; 2079 2080 // If we saw an explicit decl, use that. 2081 if (BlockObjectDisposeDecl) { 2082 return BlockObjectDispose = GetAddrOfFunction( 2083 BlockObjectDisposeDecl, 2084 getTypes().GetFunctionType(BlockObjectDisposeDecl)); 2085 } 2086 2087 // Otherwise construct the function by hand. 2088 const llvm::FunctionType *FTy; 2089 std::vector<const llvm::Type*> ArgTys; 2090 const llvm::Type *ResultType = llvm::Type::getVoidTy(VMContext); 2091 ArgTys.push_back(PtrToInt8Ty); 2092 ArgTys.push_back(llvm::Type::getInt32Ty(VMContext)); 2093 FTy = llvm::FunctionType::get(ResultType, ArgTys, false); 2094 return BlockObjectDispose = 2095 CreateRuntimeFunction(FTy, "_Block_object_dispose"); 2096} 2097 2098llvm::Constant *CodeGenModule::getBlockObjectAssign() { 2099 if (BlockObjectAssign) 2100 return BlockObjectAssign; 2101 2102 // If we saw an explicit decl, use that. 2103 if (BlockObjectAssignDecl) { 2104 return BlockObjectAssign = GetAddrOfFunction( 2105 BlockObjectAssignDecl, 2106 getTypes().GetFunctionType(BlockObjectAssignDecl)); 2107 } 2108 2109 // Otherwise construct the function by hand. 2110 const llvm::FunctionType *FTy; 2111 std::vector<const llvm::Type*> ArgTys; 2112 const llvm::Type *ResultType = llvm::Type::getVoidTy(VMContext); 2113 ArgTys.push_back(PtrToInt8Ty); 2114 ArgTys.push_back(PtrToInt8Ty); 2115 ArgTys.push_back(llvm::Type::getInt32Ty(VMContext)); 2116 FTy = llvm::FunctionType::get(ResultType, ArgTys, false); 2117 return BlockObjectAssign = 2118 CreateRuntimeFunction(FTy, "_Block_object_assign"); 2119} 2120 2121llvm::Constant *CodeGenModule::getNSConcreteGlobalBlock() { 2122 if (NSConcreteGlobalBlock) 2123 return NSConcreteGlobalBlock; 2124 2125 // If we saw an explicit decl, use that. 2126 if (NSConcreteGlobalBlockDecl) { 2127 return NSConcreteGlobalBlock = GetAddrOfGlobalVar( 2128 NSConcreteGlobalBlockDecl, 2129 getTypes().ConvertType(NSConcreteGlobalBlockDecl->getType())); 2130 } 2131 2132 // Otherwise construct the variable by hand. 2133 return NSConcreteGlobalBlock = CreateRuntimeVariable( 2134 PtrToInt8Ty, "_NSConcreteGlobalBlock"); 2135} 2136 2137llvm::Constant *CodeGenModule::getNSConcreteStackBlock() { 2138 if (NSConcreteStackBlock) 2139 return NSConcreteStackBlock; 2140 2141 // If we saw an explicit decl, use that. 2142 if (NSConcreteStackBlockDecl) { 2143 return NSConcreteStackBlock = GetAddrOfGlobalVar( 2144 NSConcreteStackBlockDecl, 2145 getTypes().ConvertType(NSConcreteStackBlockDecl->getType())); 2146 } 2147 2148 // Otherwise construct the variable by hand. 2149 return NSConcreteStackBlock = CreateRuntimeVariable( 2150 PtrToInt8Ty, "_NSConcreteStackBlock"); 2151} 2152 2153///@} 2154