CodeGenModule.cpp revision 87a4ed905e2febe64021dcdfcdc7f00b27e92f32
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" 43using namespace clang; 44using namespace CodeGen; 45 46static 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 58CodeGenModule::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 93CodeGenModule::~CodeGenModule() { 94 delete Runtime; 95 delete &ABI; 96 delete TBAA; 97 delete DebugInfo; 98} 99 100void 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 109void 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 127llvm::MDNode *CodeGenModule::getTBAAInfo(QualType QTy) { 128 if (!TBAA) 129 return 0; 130 return TBAA->getTBAAInfo(QTy); 131} 132 133void CodeGenModule::DecorateInstruction(llvm::Instruction *Inst, 134 llvm::MDNode *TBAAInfo) { 135 Inst->setMetadata(llvm::LLVMContext::MD_tbaa, TBAAInfo); 136} 137 138bool 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. 144void 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. 157void 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 167static llvm::GlobalValue::VisibilityTypes GetLLVMVisibility(Visibility V) { 168 switch (V) { 169 case DefaultVisibility: return llvm::GlobalValue::DefaultVisibility; 170 case HiddenVisibility: return llvm::GlobalValue::HiddenVisibility; 171 case ProtectedVisibility: return llvm::GlobalValue::ProtectedVisibility; 172 } 173 llvm_unreachable("unknown visibility!"); 174 return llvm::GlobalValue::DefaultVisibility; 175} 176 177 178void CodeGenModule::setGlobalVisibility(llvm::GlobalValue *GV, 179 const NamedDecl *D) const { 180 // Internal definitions always have default visibility. 181 if (GV->hasLocalLinkage()) { 182 GV->setVisibility(llvm::GlobalValue::DefaultVisibility); 183 return; 184 } 185 186 GV->setVisibility(GetLLVMVisibility(D->getVisibility())); 187} 188 189/// Set the symbol visibility of type information (vtable and RTTI) 190/// associated with the given type. 191void CodeGenModule::setTypeVisibility(llvm::GlobalValue *GV, 192 const CXXRecordDecl *RD, 193 bool IsForRTTI) const { 194 setGlobalVisibility(GV, RD); 195 196 if (!CodeGenOpts.HiddenWeakVTables) 197 return; 198 199 // We want to drop the visibility to hidden for weak type symbols. 200 // This isn't possible if there might be unresolved references 201 // elsewhere that rely on this symbol being visible. 202 203 // This should be kept roughly in sync with setThunkVisibility 204 // in CGVTables.cpp. 205 206 // Preconditions. 207 if (GV->getLinkage() != llvm::GlobalVariable::WeakODRLinkage || 208 GV->getVisibility() != llvm::GlobalVariable::DefaultVisibility) 209 return; 210 211 // Don't override an explicit visibility attribute. 212 if (RD->hasAttr<VisibilityAttr>()) 213 return; 214 215 switch (RD->getTemplateSpecializationKind()) { 216 // We have to disable the optimization if this is an EI definition 217 // because there might be EI declarations in other shared objects. 218 case TSK_ExplicitInstantiationDefinition: 219 case TSK_ExplicitInstantiationDeclaration: 220 return; 221 222 // Every use of a non-template class's type information has to emit it. 223 case TSK_Undeclared: 224 break; 225 226 // In theory, implicit instantiations can ignore the possibility of 227 // an explicit instantiation declaration because there necessarily 228 // must be an EI definition somewhere with default visibility. In 229 // practice, it's possible to have an explicit instantiation for 230 // an arbitrary template class, and linkers aren't necessarily able 231 // to deal with mixed-visibility symbols. 232 case TSK_ExplicitSpecialization: 233 case TSK_ImplicitInstantiation: 234 if (!CodeGenOpts.HiddenWeakTemplateVTables) 235 return; 236 break; 237 } 238 239 // If there's a key function, there may be translation units 240 // that don't have the key function's definition. But ignore 241 // this if we're emitting RTTI under -fno-rtti. 242 if (!IsForRTTI || Features.RTTI) 243 if (Context.getKeyFunction(RD)) 244 return; 245 246 // Otherwise, drop the visibility to hidden. 247 GV->setVisibility(llvm::GlobalValue::HiddenVisibility); 248} 249 250llvm::StringRef CodeGenModule::getMangledName(GlobalDecl GD) { 251 const NamedDecl *ND = cast<NamedDecl>(GD.getDecl()); 252 253 llvm::StringRef &Str = MangledDeclNames[GD.getCanonicalDecl()]; 254 if (!Str.empty()) 255 return Str; 256 257 if (!getCXXABI().getMangleContext().shouldMangleDeclName(ND)) { 258 IdentifierInfo *II = ND->getIdentifier(); 259 assert(II && "Attempt to mangle unnamed decl."); 260 261 Str = II->getName(); 262 return Str; 263 } 264 265 llvm::SmallString<256> Buffer; 266 if (const CXXConstructorDecl *D = dyn_cast<CXXConstructorDecl>(ND)) 267 getCXXABI().getMangleContext().mangleCXXCtor(D, GD.getCtorType(), Buffer); 268 else if (const CXXDestructorDecl *D = dyn_cast<CXXDestructorDecl>(ND)) 269 getCXXABI().getMangleContext().mangleCXXDtor(D, GD.getDtorType(), Buffer); 270 else if (const BlockDecl *BD = dyn_cast<BlockDecl>(ND)) 271 getCXXABI().getMangleContext().mangleBlock(GD, BD, Buffer); 272 else 273 getCXXABI().getMangleContext().mangleName(ND, Buffer); 274 275 // Allocate space for the mangled name. 276 size_t Length = Buffer.size(); 277 char *Name = MangledNamesAllocator.Allocate<char>(Length); 278 std::copy(Buffer.begin(), Buffer.end(), Name); 279 280 Str = llvm::StringRef(Name, Length); 281 282 return Str; 283} 284 285void CodeGenModule::getMangledName(GlobalDecl GD, MangleBuffer &Buffer, 286 const BlockDecl *BD) { 287 getCXXABI().getMangleContext().mangleBlock(GD, BD, Buffer.getBuffer()); 288} 289 290llvm::GlobalValue *CodeGenModule::GetGlobalValue(llvm::StringRef Name) { 291 return getModule().getNamedValue(Name); 292} 293 294/// AddGlobalCtor - Add a function to the list that will be called before 295/// main() runs. 296void CodeGenModule::AddGlobalCtor(llvm::Function * Ctor, int Priority) { 297 // FIXME: Type coercion of void()* types. 298 GlobalCtors.push_back(std::make_pair(Ctor, Priority)); 299} 300 301/// AddGlobalDtor - Add a function to the list that will be called 302/// when the module is unloaded. 303void CodeGenModule::AddGlobalDtor(llvm::Function * Dtor, int Priority) { 304 // FIXME: Type coercion of void()* types. 305 GlobalDtors.push_back(std::make_pair(Dtor, Priority)); 306} 307 308void CodeGenModule::EmitCtorList(const CtorList &Fns, const char *GlobalName) { 309 // Ctor function type is void()*. 310 llvm::FunctionType* CtorFTy = 311 llvm::FunctionType::get(llvm::Type::getVoidTy(VMContext), 312 std::vector<const llvm::Type*>(), 313 false); 314 llvm::Type *CtorPFTy = llvm::PointerType::getUnqual(CtorFTy); 315 316 // Get the type of a ctor entry, { i32, void ()* }. 317 llvm::StructType* CtorStructTy = 318 llvm::StructType::get(VMContext, llvm::Type::getInt32Ty(VMContext), 319 llvm::PointerType::getUnqual(CtorFTy), NULL); 320 321 // Construct the constructor and destructor arrays. 322 std::vector<llvm::Constant*> Ctors; 323 for (CtorList::const_iterator I = Fns.begin(), E = Fns.end(); I != E; ++I) { 324 std::vector<llvm::Constant*> S; 325 S.push_back(llvm::ConstantInt::get(llvm::Type::getInt32Ty(VMContext), 326 I->second, false)); 327 S.push_back(llvm::ConstantExpr::getBitCast(I->first, CtorPFTy)); 328 Ctors.push_back(llvm::ConstantStruct::get(CtorStructTy, S)); 329 } 330 331 if (!Ctors.empty()) { 332 llvm::ArrayType *AT = llvm::ArrayType::get(CtorStructTy, Ctors.size()); 333 new llvm::GlobalVariable(TheModule, AT, false, 334 llvm::GlobalValue::AppendingLinkage, 335 llvm::ConstantArray::get(AT, Ctors), 336 GlobalName); 337 } 338} 339 340void CodeGenModule::EmitAnnotations() { 341 if (Annotations.empty()) 342 return; 343 344 // Create a new global variable for the ConstantStruct in the Module. 345 llvm::Constant *Array = 346 llvm::ConstantArray::get(llvm::ArrayType::get(Annotations[0]->getType(), 347 Annotations.size()), 348 Annotations); 349 llvm::GlobalValue *gv = 350 new llvm::GlobalVariable(TheModule, Array->getType(), false, 351 llvm::GlobalValue::AppendingLinkage, Array, 352 "llvm.global.annotations"); 353 gv->setSection("llvm.metadata"); 354} 355 356llvm::GlobalValue::LinkageTypes 357CodeGenModule::getFunctionLinkage(const FunctionDecl *D) { 358 GVALinkage Linkage = getContext().GetGVALinkageForFunction(D); 359 360 if (Linkage == GVA_Internal) 361 return llvm::Function::InternalLinkage; 362 363 if (D->hasAttr<DLLExportAttr>()) 364 return llvm::Function::DLLExportLinkage; 365 366 if (D->hasAttr<WeakAttr>()) 367 return llvm::Function::WeakAnyLinkage; 368 369 // In C99 mode, 'inline' functions are guaranteed to have a strong 370 // definition somewhere else, so we can use available_externally linkage. 371 if (Linkage == GVA_C99Inline) 372 return llvm::Function::AvailableExternallyLinkage; 373 374 // In C++, the compiler has to emit a definition in every translation unit 375 // that references the function. We should use linkonce_odr because 376 // a) if all references in this translation unit are optimized away, we 377 // don't need to codegen it. b) if the function persists, it needs to be 378 // merged with other definitions. c) C++ has the ODR, so we know the 379 // definition is dependable. 380 if (Linkage == GVA_CXXInline || Linkage == GVA_TemplateInstantiation) 381 return llvm::Function::LinkOnceODRLinkage; 382 383 // An explicit instantiation of a template has weak linkage, since 384 // explicit instantiations can occur in multiple translation units 385 // and must all be equivalent. However, we are not allowed to 386 // throw away these explicit instantiations. 387 if (Linkage == GVA_ExplicitTemplateInstantiation) 388 return llvm::Function::WeakODRLinkage; 389 390 // Otherwise, we have strong external linkage. 391 assert(Linkage == GVA_StrongExternal); 392 return llvm::Function::ExternalLinkage; 393} 394 395 396/// SetFunctionDefinitionAttributes - Set attributes for a global. 397/// 398/// FIXME: This is currently only done for aliases and functions, but not for 399/// variables (these details are set in EmitGlobalVarDefinition for variables). 400void CodeGenModule::SetFunctionDefinitionAttributes(const FunctionDecl *D, 401 llvm::GlobalValue *GV) { 402 SetCommonAttributes(D, GV); 403} 404 405void CodeGenModule::SetLLVMFunctionAttributes(const Decl *D, 406 const CGFunctionInfo &Info, 407 llvm::Function *F) { 408 unsigned CallingConv; 409 AttributeListType AttributeList; 410 ConstructAttributeList(Info, D, AttributeList, CallingConv); 411 F->setAttributes(llvm::AttrListPtr::get(AttributeList.begin(), 412 AttributeList.size())); 413 F->setCallingConv(static_cast<llvm::CallingConv::ID>(CallingConv)); 414} 415 416void CodeGenModule::SetLLVMFunctionAttributesForDefinition(const Decl *D, 417 llvm::Function *F) { 418 if (!Features.Exceptions && !Features.ObjCNonFragileABI) 419 F->addFnAttr(llvm::Attribute::NoUnwind); 420 421 if (D->hasAttr<AlwaysInlineAttr>()) 422 F->addFnAttr(llvm::Attribute::AlwaysInline); 423 424 if (D->hasAttr<NakedAttr>()) 425 F->addFnAttr(llvm::Attribute::Naked); 426 427 if (D->hasAttr<NoInlineAttr>()) 428 F->addFnAttr(llvm::Attribute::NoInline); 429 430 if (Features.getStackProtectorMode() == LangOptions::SSPOn) 431 F->addFnAttr(llvm::Attribute::StackProtect); 432 else if (Features.getStackProtectorMode() == LangOptions::SSPReq) 433 F->addFnAttr(llvm::Attribute::StackProtectReq); 434 435 unsigned alignment = D->getMaxAlignment() / Context.getCharWidth(); 436 if (alignment) 437 F->setAlignment(alignment); 438 439 // C++ ABI requires 2-byte alignment for member functions. 440 if (F->getAlignment() < 2 && isa<CXXMethodDecl>(D)) 441 F->setAlignment(2); 442} 443 444void CodeGenModule::SetCommonAttributes(const Decl *D, 445 llvm::GlobalValue *GV) { 446 if (isa<NamedDecl>(D)) 447 setGlobalVisibility(GV, cast<NamedDecl>(D)); 448 else 449 GV->setVisibility(llvm::GlobalValue::DefaultVisibility); 450 451 if (D->hasAttr<UsedAttr>()) 452 AddUsedGlobal(GV); 453 454 if (const SectionAttr *SA = D->getAttr<SectionAttr>()) 455 GV->setSection(SA->getName()); 456 457 getTargetCodeGenInfo().SetTargetAttributes(D, GV, *this); 458} 459 460void CodeGenModule::SetInternalFunctionAttributes(const Decl *D, 461 llvm::Function *F, 462 const CGFunctionInfo &FI) { 463 SetLLVMFunctionAttributes(D, FI, F); 464 SetLLVMFunctionAttributesForDefinition(D, F); 465 466 F->setLinkage(llvm::Function::InternalLinkage); 467 468 SetCommonAttributes(D, F); 469} 470 471void CodeGenModule::SetFunctionAttributes(GlobalDecl GD, 472 llvm::Function *F, 473 bool IsIncompleteFunction) { 474 const FunctionDecl *FD = cast<FunctionDecl>(GD.getDecl()); 475 476 if (!IsIncompleteFunction) 477 SetLLVMFunctionAttributes(FD, getTypes().getFunctionInfo(GD), F); 478 479 // Only a few attributes are set on declarations; these may later be 480 // overridden by a definition. 481 482 if (FD->hasAttr<DLLImportAttr>()) { 483 F->setLinkage(llvm::Function::DLLImportLinkage); 484 } else if (FD->hasAttr<WeakAttr>() || 485 FD->hasAttr<WeakImportAttr>()) { 486 // "extern_weak" is overloaded in LLVM; we probably should have 487 // separate linkage types for this. 488 F->setLinkage(llvm::Function::ExternalWeakLinkage); 489 } else { 490 F->setLinkage(llvm::Function::ExternalLinkage); 491 } 492 493 if (const SectionAttr *SA = FD->getAttr<SectionAttr>()) 494 F->setSection(SA->getName()); 495} 496 497void CodeGenModule::AddUsedGlobal(llvm::GlobalValue *GV) { 498 assert(!GV->isDeclaration() && 499 "Only globals with definition can force usage."); 500 LLVMUsed.push_back(GV); 501} 502 503void CodeGenModule::EmitLLVMUsed() { 504 // Don't create llvm.used if there is no need. 505 if (LLVMUsed.empty()) 506 return; 507 508 const llvm::Type *i8PTy = llvm::Type::getInt8PtrTy(VMContext); 509 510 // Convert LLVMUsed to what ConstantArray needs. 511 std::vector<llvm::Constant*> UsedArray; 512 UsedArray.resize(LLVMUsed.size()); 513 for (unsigned i = 0, e = LLVMUsed.size(); i != e; ++i) { 514 UsedArray[i] = 515 llvm::ConstantExpr::getBitCast(cast<llvm::Constant>(&*LLVMUsed[i]), 516 i8PTy); 517 } 518 519 if (UsedArray.empty()) 520 return; 521 llvm::ArrayType *ATy = llvm::ArrayType::get(i8PTy, UsedArray.size()); 522 523 llvm::GlobalVariable *GV = 524 new llvm::GlobalVariable(getModule(), ATy, false, 525 llvm::GlobalValue::AppendingLinkage, 526 llvm::ConstantArray::get(ATy, UsedArray), 527 "llvm.used"); 528 529 GV->setSection("llvm.metadata"); 530} 531 532void CodeGenModule::EmitDeferred() { 533 // Emit code for any potentially referenced deferred decls. Since a 534 // previously unused static decl may become used during the generation of code 535 // for a static function, iterate until no changes are made. 536 537 while (!DeferredDeclsToEmit.empty() || !DeferredVTables.empty()) { 538 if (!DeferredVTables.empty()) { 539 const CXXRecordDecl *RD = DeferredVTables.back(); 540 DeferredVTables.pop_back(); 541 getVTables().GenerateClassData(getVTableLinkage(RD), RD); 542 continue; 543 } 544 545 GlobalDecl D = DeferredDeclsToEmit.back(); 546 DeferredDeclsToEmit.pop_back(); 547 548 // Check to see if we've already emitted this. This is necessary 549 // for a couple of reasons: first, decls can end up in the 550 // deferred-decls queue multiple times, and second, decls can end 551 // up with definitions in unusual ways (e.g. by an extern inline 552 // function acquiring a strong function redefinition). Just 553 // ignore these cases. 554 // 555 // TODO: That said, looking this up multiple times is very wasteful. 556 llvm::StringRef Name = getMangledName(D); 557 llvm::GlobalValue *CGRef = GetGlobalValue(Name); 558 assert(CGRef && "Deferred decl wasn't referenced?"); 559 560 if (!CGRef->isDeclaration()) 561 continue; 562 563 // GlobalAlias::isDeclaration() defers to the aliasee, but for our 564 // purposes an alias counts as a definition. 565 if (isa<llvm::GlobalAlias>(CGRef)) 566 continue; 567 568 // Otherwise, emit the definition and move on to the next one. 569 EmitGlobalDefinition(D); 570 } 571} 572 573/// EmitAnnotateAttr - Generate the llvm::ConstantStruct which contains the 574/// annotation information for a given GlobalValue. The annotation struct is 575/// {i8 *, i8 *, i8 *, i32}. The first field is a constant expression, the 576/// GlobalValue being annotated. The second field is the constant string 577/// created from the AnnotateAttr's annotation. The third field is a constant 578/// string containing the name of the translation unit. The fourth field is 579/// the line number in the file of the annotated value declaration. 580/// 581/// FIXME: this does not unique the annotation string constants, as llvm-gcc 582/// appears to. 583/// 584llvm::Constant *CodeGenModule::EmitAnnotateAttr(llvm::GlobalValue *GV, 585 const AnnotateAttr *AA, 586 unsigned LineNo) { 587 llvm::Module *M = &getModule(); 588 589 // get [N x i8] constants for the annotation string, and the filename string 590 // which are the 2nd and 3rd elements of the global annotation structure. 591 const llvm::Type *SBP = llvm::Type::getInt8PtrTy(VMContext); 592 llvm::Constant *anno = llvm::ConstantArray::get(VMContext, 593 AA->getAnnotation(), true); 594 llvm::Constant *unit = llvm::ConstantArray::get(VMContext, 595 M->getModuleIdentifier(), 596 true); 597 598 // Get the two global values corresponding to the ConstantArrays we just 599 // created to hold the bytes of the strings. 600 llvm::GlobalValue *annoGV = 601 new llvm::GlobalVariable(*M, anno->getType(), false, 602 llvm::GlobalValue::PrivateLinkage, anno, 603 GV->getName()); 604 // translation unit name string, emitted into the llvm.metadata section. 605 llvm::GlobalValue *unitGV = 606 new llvm::GlobalVariable(*M, unit->getType(), false, 607 llvm::GlobalValue::PrivateLinkage, unit, 608 ".str"); 609 610 // Create the ConstantStruct for the global annotation. 611 llvm::Constant *Fields[4] = { 612 llvm::ConstantExpr::getBitCast(GV, SBP), 613 llvm::ConstantExpr::getBitCast(annoGV, SBP), 614 llvm::ConstantExpr::getBitCast(unitGV, SBP), 615 llvm::ConstantInt::get(llvm::Type::getInt32Ty(VMContext), LineNo) 616 }; 617 return llvm::ConstantStruct::get(VMContext, Fields, 4, false); 618} 619 620bool CodeGenModule::MayDeferGeneration(const ValueDecl *Global) { 621 // Never defer when EmitAllDecls is specified. 622 if (Features.EmitAllDecls) 623 return false; 624 625 return !getContext().DeclMustBeEmitted(Global); 626} 627 628llvm::Constant *CodeGenModule::GetWeakRefReference(const ValueDecl *VD) { 629 const AliasAttr *AA = VD->getAttr<AliasAttr>(); 630 assert(AA && "No alias?"); 631 632 const llvm::Type *DeclTy = getTypes().ConvertTypeForMem(VD->getType()); 633 634 // See if there is already something with the target's name in the module. 635 llvm::GlobalValue *Entry = GetGlobalValue(AA->getAliasee()); 636 637 llvm::Constant *Aliasee; 638 if (isa<llvm::FunctionType>(DeclTy)) 639 Aliasee = GetOrCreateLLVMFunction(AA->getAliasee(), DeclTy, GlobalDecl()); 640 else 641 Aliasee = GetOrCreateLLVMGlobal(AA->getAliasee(), 642 llvm::PointerType::getUnqual(DeclTy), 0); 643 if (!Entry) { 644 llvm::GlobalValue* F = cast<llvm::GlobalValue>(Aliasee); 645 F->setLinkage(llvm::Function::ExternalWeakLinkage); 646 WeakRefReferences.insert(F); 647 } 648 649 return Aliasee; 650} 651 652void CodeGenModule::EmitGlobal(GlobalDecl GD) { 653 const ValueDecl *Global = cast<ValueDecl>(GD.getDecl()); 654 655 // Weak references don't produce any output by themselves. 656 if (Global->hasAttr<WeakRefAttr>()) 657 return; 658 659 // If this is an alias definition (which otherwise looks like a declaration) 660 // emit it now. 661 if (Global->hasAttr<AliasAttr>()) 662 return EmitAliasDefinition(GD); 663 664 // Ignore declarations, they will be emitted on their first use. 665 if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(Global)) { 666 if (FD->getIdentifier()) { 667 llvm::StringRef Name = FD->getName(); 668 if (Name == "_Block_object_assign") { 669 BlockObjectAssignDecl = FD; 670 } else if (Name == "_Block_object_dispose") { 671 BlockObjectDisposeDecl = FD; 672 } 673 } 674 675 // Forward declarations are emitted lazily on first use. 676 if (!FD->isThisDeclarationADefinition()) 677 return; 678 } else { 679 const VarDecl *VD = cast<VarDecl>(Global); 680 assert(VD->isFileVarDecl() && "Cannot emit local var decl as global."); 681 682 if (VD->getIdentifier()) { 683 llvm::StringRef Name = VD->getName(); 684 if (Name == "_NSConcreteGlobalBlock") { 685 NSConcreteGlobalBlockDecl = VD; 686 } else if (Name == "_NSConcreteStackBlock") { 687 NSConcreteStackBlockDecl = VD; 688 } 689 } 690 691 692 if (VD->isThisDeclarationADefinition() != VarDecl::Definition) 693 return; 694 } 695 696 // Defer code generation when possible if this is a static definition, inline 697 // function etc. These we only want to emit if they are used. 698 if (!MayDeferGeneration(Global)) { 699 // Emit the definition if it can't be deferred. 700 EmitGlobalDefinition(GD); 701 return; 702 } 703 704 // If we're deferring emission of a C++ variable with an 705 // initializer, remember the order in which it appeared in the file. 706 if (getLangOptions().CPlusPlus && isa<VarDecl>(Global) && 707 cast<VarDecl>(Global)->hasInit()) { 708 DelayedCXXInitPosition[Global] = CXXGlobalInits.size(); 709 CXXGlobalInits.push_back(0); 710 } 711 712 // If the value has already been used, add it directly to the 713 // DeferredDeclsToEmit list. 714 llvm::StringRef MangledName = getMangledName(GD); 715 if (GetGlobalValue(MangledName)) 716 DeferredDeclsToEmit.push_back(GD); 717 else { 718 // Otherwise, remember that we saw a deferred decl with this name. The 719 // first use of the mangled name will cause it to move into 720 // DeferredDeclsToEmit. 721 DeferredDecls[MangledName] = GD; 722 } 723} 724 725void CodeGenModule::EmitGlobalDefinition(GlobalDecl GD) { 726 const ValueDecl *D = cast<ValueDecl>(GD.getDecl()); 727 728 PrettyStackTraceDecl CrashInfo(const_cast<ValueDecl *>(D), D->getLocation(), 729 Context.getSourceManager(), 730 "Generating code for declaration"); 731 732 if (const FunctionDecl *Function = dyn_cast<FunctionDecl>(D)) { 733 // At -O0, don't generate IR for functions with available_externally 734 // linkage. 735 if (CodeGenOpts.OptimizationLevel == 0 && 736 !Function->hasAttr<AlwaysInlineAttr>() && 737 getFunctionLinkage(Function) 738 == llvm::Function::AvailableExternallyLinkage) 739 return; 740 741 if (const CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(D)) { 742 if (Method->isVirtual()) 743 getVTables().EmitThunks(GD); 744 745 if (const CXXConstructorDecl *CD = dyn_cast<CXXConstructorDecl>(Method)) 746 return EmitCXXConstructor(CD, GD.getCtorType()); 747 748 if (const CXXDestructorDecl *DD = dyn_cast<CXXDestructorDecl>(Method)) 749 return EmitCXXDestructor(DD, GD.getDtorType()); 750 } 751 752 return EmitGlobalFunctionDefinition(GD); 753 } 754 755 if (const VarDecl *VD = dyn_cast<VarDecl>(D)) 756 return EmitGlobalVarDefinition(VD); 757 758 assert(0 && "Invalid argument to EmitGlobalDefinition()"); 759} 760 761/// GetOrCreateLLVMFunction - If the specified mangled name is not in the 762/// module, create and return an llvm Function with the specified type. If there 763/// is something in the module with the specified name, return it potentially 764/// bitcasted to the right type. 765/// 766/// If D is non-null, it specifies a decl that correspond to this. This is used 767/// to set the attributes on the function when it is first created. 768llvm::Constant * 769CodeGenModule::GetOrCreateLLVMFunction(llvm::StringRef MangledName, 770 const llvm::Type *Ty, 771 GlobalDecl D) { 772 // Lookup the entry, lazily creating it if necessary. 773 llvm::GlobalValue *Entry = GetGlobalValue(MangledName); 774 if (Entry) { 775 if (WeakRefReferences.count(Entry)) { 776 const FunctionDecl *FD = cast_or_null<FunctionDecl>(D.getDecl()); 777 if (FD && !FD->hasAttr<WeakAttr>()) 778 Entry->setLinkage(llvm::Function::ExternalLinkage); 779 780 WeakRefReferences.erase(Entry); 781 } 782 783 if (Entry->getType()->getElementType() == Ty) 784 return Entry; 785 786 // Make sure the result is of the correct type. 787 const llvm::Type *PTy = llvm::PointerType::getUnqual(Ty); 788 return llvm::ConstantExpr::getBitCast(Entry, PTy); 789 } 790 791 // This function doesn't have a complete type (for example, the return 792 // type is an incomplete struct). Use a fake type instead, and make 793 // sure not to try to set attributes. 794 bool IsIncompleteFunction = false; 795 796 const llvm::FunctionType *FTy; 797 if (isa<llvm::FunctionType>(Ty)) { 798 FTy = cast<llvm::FunctionType>(Ty); 799 } else { 800 FTy = llvm::FunctionType::get(llvm::Type::getVoidTy(VMContext), 801 std::vector<const llvm::Type*>(), false); 802 IsIncompleteFunction = true; 803 } 804 805 llvm::Function *F = llvm::Function::Create(FTy, 806 llvm::Function::ExternalLinkage, 807 MangledName, &getModule()); 808 assert(F->getName() == MangledName && "name was uniqued!"); 809 if (D.getDecl()) 810 SetFunctionAttributes(D, F, IsIncompleteFunction); 811 812 // This is the first use or definition of a mangled name. If there is a 813 // deferred decl with this name, remember that we need to emit it at the end 814 // of the file. 815 llvm::StringMap<GlobalDecl>::iterator DDI = DeferredDecls.find(MangledName); 816 if (DDI != DeferredDecls.end()) { 817 // Move the potentially referenced deferred decl to the DeferredDeclsToEmit 818 // list, and remove it from DeferredDecls (since we don't need it anymore). 819 DeferredDeclsToEmit.push_back(DDI->second); 820 DeferredDecls.erase(DDI); 821 } else if (const FunctionDecl *FD = cast_or_null<FunctionDecl>(D.getDecl())) { 822 // If this the first reference to a C++ inline function in a class, queue up 823 // the deferred function body for emission. These are not seen as 824 // top-level declarations. 825 if (FD->isThisDeclarationADefinition() && MayDeferGeneration(FD)) 826 DeferredDeclsToEmit.push_back(D); 827 // A called constructor which has no definition or declaration need be 828 // synthesized. 829 else if (const CXXConstructorDecl *CD = dyn_cast<CXXConstructorDecl>(FD)) { 830 if (CD->isImplicit()) { 831 assert(CD->isUsed() && "Sema doesn't consider constructor as used."); 832 DeferredDeclsToEmit.push_back(D); 833 } 834 } else if (const CXXDestructorDecl *DD = dyn_cast<CXXDestructorDecl>(FD)) { 835 if (DD->isImplicit()) { 836 assert(DD->isUsed() && "Sema doesn't consider destructor as used."); 837 DeferredDeclsToEmit.push_back(D); 838 } 839 } else if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(FD)) { 840 if (MD->isImplicit() && MD->isCopyAssignmentOperator()) { 841 assert(MD->isUsed() && "Sema doesn't consider CopyAssignment as used."); 842 DeferredDeclsToEmit.push_back(D); 843 } 844 } 845 } 846 847 // Make sure the result is of the requested type. 848 if (!IsIncompleteFunction) { 849 assert(F->getType()->getElementType() == Ty); 850 return F; 851 } 852 853 const llvm::Type *PTy = llvm::PointerType::getUnqual(Ty); 854 return llvm::ConstantExpr::getBitCast(F, PTy); 855} 856 857/// GetAddrOfFunction - Return the address of the given function. If Ty is 858/// non-null, then this function will use the specified type if it has to 859/// create it (this occurs when we see a definition of the function). 860llvm::Constant *CodeGenModule::GetAddrOfFunction(GlobalDecl GD, 861 const llvm::Type *Ty) { 862 // If there was no specific requested type, just convert it now. 863 if (!Ty) 864 Ty = getTypes().ConvertType(cast<ValueDecl>(GD.getDecl())->getType()); 865 866 llvm::StringRef MangledName = getMangledName(GD); 867 return GetOrCreateLLVMFunction(MangledName, Ty, GD); 868} 869 870/// CreateRuntimeFunction - Create a new runtime function with the specified 871/// type and name. 872llvm::Constant * 873CodeGenModule::CreateRuntimeFunction(const llvm::FunctionType *FTy, 874 llvm::StringRef Name) { 875 return GetOrCreateLLVMFunction(Name, FTy, GlobalDecl()); 876} 877 878static bool DeclIsConstantGlobal(ASTContext &Context, const VarDecl *D) { 879 if (!D->getType().isConstant(Context) && !D->getType()->isReferenceType()) 880 return false; 881 if (Context.getLangOptions().CPlusPlus && 882 Context.getBaseElementType(D->getType())->getAs<RecordType>()) { 883 // FIXME: We should do something fancier here! 884 return false; 885 } 886 return true; 887} 888 889/// GetOrCreateLLVMGlobal - If the specified mangled name is not in the module, 890/// create and return an llvm GlobalVariable with the specified type. If there 891/// is something in the module with the specified name, return it potentially 892/// bitcasted to the right type. 893/// 894/// If D is non-null, it specifies a decl that correspond to this. This is used 895/// to set the attributes on the global when it is first created. 896llvm::Constant * 897CodeGenModule::GetOrCreateLLVMGlobal(llvm::StringRef MangledName, 898 const llvm::PointerType *Ty, 899 const VarDecl *D) { 900 // Lookup the entry, lazily creating it if necessary. 901 llvm::GlobalValue *Entry = GetGlobalValue(MangledName); 902 if (Entry) { 903 if (WeakRefReferences.count(Entry)) { 904 if (D && !D->hasAttr<WeakAttr>()) 905 Entry->setLinkage(llvm::Function::ExternalLinkage); 906 907 WeakRefReferences.erase(Entry); 908 } 909 910 if (Entry->getType() == Ty) 911 return Entry; 912 913 // Make sure the result is of the correct type. 914 return llvm::ConstantExpr::getBitCast(Entry, Ty); 915 } 916 917 // This is the first use or definition of a mangled name. If there is a 918 // deferred decl with this name, remember that we need to emit it at the end 919 // of the file. 920 llvm::StringMap<GlobalDecl>::iterator DDI = DeferredDecls.find(MangledName); 921 if (DDI != DeferredDecls.end()) { 922 // Move the potentially referenced deferred decl to the DeferredDeclsToEmit 923 // list, and remove it from DeferredDecls (since we don't need it anymore). 924 DeferredDeclsToEmit.push_back(DDI->second); 925 DeferredDecls.erase(DDI); 926 } 927 928 llvm::GlobalVariable *GV = 929 new llvm::GlobalVariable(getModule(), Ty->getElementType(), false, 930 llvm::GlobalValue::ExternalLinkage, 931 0, MangledName, 0, 932 false, Ty->getAddressSpace()); 933 934 // Handle things which are present even on external declarations. 935 if (D) { 936 // FIXME: This code is overly simple and should be merged with other global 937 // handling. 938 GV->setConstant(DeclIsConstantGlobal(Context, D)); 939 940 // Set linkage and visibility in case we never see a definition. 941 std::pair<Linkage,Visibility> LV = D->getLinkageAndVisibility(); 942 if (LV.first != ExternalLinkage) { 943 GV->setLinkage(llvm::GlobalValue::InternalLinkage); 944 } else { 945 if (D->hasAttr<DLLImportAttr>()) 946 GV->setLinkage(llvm::GlobalValue::DLLImportLinkage); 947 else if (D->hasAttr<WeakAttr>() || D->hasAttr<WeakImportAttr>()) 948 GV->setLinkage(llvm::GlobalValue::ExternalWeakLinkage); 949 950 GV->setVisibility(GetLLVMVisibility(LV.second)); 951 } 952 953 GV->setThreadLocal(D->isThreadSpecified()); 954 } 955 956 return GV; 957} 958 959 960/// GetAddrOfGlobalVar - Return the llvm::Constant for the address of the 961/// given global variable. If Ty is non-null and if the global doesn't exist, 962/// then it will be greated with the specified type instead of whatever the 963/// normal requested type would be. 964llvm::Constant *CodeGenModule::GetAddrOfGlobalVar(const VarDecl *D, 965 const llvm::Type *Ty) { 966 assert(D->hasGlobalStorage() && "Not a global variable"); 967 QualType ASTTy = D->getType(); 968 if (Ty == 0) 969 Ty = getTypes().ConvertTypeForMem(ASTTy); 970 971 const llvm::PointerType *PTy = 972 llvm::PointerType::get(Ty, ASTTy.getAddressSpace()); 973 974 llvm::StringRef MangledName = getMangledName(D); 975 return GetOrCreateLLVMGlobal(MangledName, PTy, D); 976} 977 978/// CreateRuntimeVariable - Create a new runtime global variable with the 979/// specified type and name. 980llvm::Constant * 981CodeGenModule::CreateRuntimeVariable(const llvm::Type *Ty, 982 llvm::StringRef Name) { 983 return GetOrCreateLLVMGlobal(Name, llvm::PointerType::getUnqual(Ty), 0); 984} 985 986void CodeGenModule::EmitTentativeDefinition(const VarDecl *D) { 987 assert(!D->getInit() && "Cannot emit definite definitions here!"); 988 989 if (MayDeferGeneration(D)) { 990 // If we have not seen a reference to this variable yet, place it 991 // into the deferred declarations table to be emitted if needed 992 // later. 993 llvm::StringRef MangledName = getMangledName(D); 994 if (!GetGlobalValue(MangledName)) { 995 DeferredDecls[MangledName] = D; 996 return; 997 } 998 } 999 1000 // The tentative definition is the only definition. 1001 EmitGlobalVarDefinition(D); 1002} 1003 1004void CodeGenModule::EmitVTable(CXXRecordDecl *Class, bool DefinitionRequired) { 1005 if (DefinitionRequired) 1006 getVTables().GenerateClassData(getVTableLinkage(Class), Class); 1007} 1008 1009llvm::GlobalVariable::LinkageTypes 1010CodeGenModule::getVTableLinkage(const CXXRecordDecl *RD) { 1011 if (RD->isInAnonymousNamespace() || !RD->hasLinkage()) 1012 return llvm::GlobalVariable::InternalLinkage; 1013 1014 if (const CXXMethodDecl *KeyFunction 1015 = RD->getASTContext().getKeyFunction(RD)) { 1016 // If this class has a key function, use that to determine the linkage of 1017 // the vtable. 1018 const FunctionDecl *Def = 0; 1019 if (KeyFunction->hasBody(Def)) 1020 KeyFunction = cast<CXXMethodDecl>(Def); 1021 1022 switch (KeyFunction->getTemplateSpecializationKind()) { 1023 case TSK_Undeclared: 1024 case TSK_ExplicitSpecialization: 1025 if (KeyFunction->isInlined()) 1026 return llvm::GlobalVariable::WeakODRLinkage; 1027 1028 return llvm::GlobalVariable::ExternalLinkage; 1029 1030 case TSK_ImplicitInstantiation: 1031 case TSK_ExplicitInstantiationDefinition: 1032 return llvm::GlobalVariable::WeakODRLinkage; 1033 1034 case TSK_ExplicitInstantiationDeclaration: 1035 // FIXME: Use available_externally linkage. However, this currently 1036 // breaks LLVM's build due to undefined symbols. 1037 // return llvm::GlobalVariable::AvailableExternallyLinkage; 1038 return llvm::GlobalVariable::WeakODRLinkage; 1039 } 1040 } 1041 1042 switch (RD->getTemplateSpecializationKind()) { 1043 case TSK_Undeclared: 1044 case TSK_ExplicitSpecialization: 1045 case TSK_ImplicitInstantiation: 1046 case TSK_ExplicitInstantiationDefinition: 1047 return llvm::GlobalVariable::WeakODRLinkage; 1048 1049 case TSK_ExplicitInstantiationDeclaration: 1050 // FIXME: Use available_externally linkage. However, this currently 1051 // breaks LLVM's build due to undefined symbols. 1052 // return llvm::GlobalVariable::AvailableExternallyLinkage; 1053 return llvm::GlobalVariable::WeakODRLinkage; 1054 } 1055 1056 // Silence GCC warning. 1057 return llvm::GlobalVariable::WeakODRLinkage; 1058} 1059 1060CharUnits CodeGenModule::GetTargetTypeStoreSize(const llvm::Type *Ty) const { 1061 return CharUnits::fromQuantity( 1062 TheTargetData.getTypeStoreSizeInBits(Ty) / Context.getCharWidth()); 1063} 1064 1065void CodeGenModule::EmitGlobalVarDefinition(const VarDecl *D) { 1066 llvm::Constant *Init = 0; 1067 QualType ASTTy = D->getType(); 1068 bool NonConstInit = false; 1069 1070 const Expr *InitExpr = D->getAnyInitializer(); 1071 1072 if (!InitExpr) { 1073 // This is a tentative definition; tentative definitions are 1074 // implicitly initialized with { 0 }. 1075 // 1076 // Note that tentative definitions are only emitted at the end of 1077 // a translation unit, so they should never have incomplete 1078 // type. In addition, EmitTentativeDefinition makes sure that we 1079 // never attempt to emit a tentative definition if a real one 1080 // exists. A use may still exists, however, so we still may need 1081 // to do a RAUW. 1082 assert(!ASTTy->isIncompleteType() && "Unexpected incomplete type"); 1083 Init = EmitNullConstant(D->getType()); 1084 } else { 1085 Init = EmitConstantExpr(InitExpr, D->getType()); 1086 if (!Init) { 1087 QualType T = InitExpr->getType(); 1088 if (D->getType()->isReferenceType()) 1089 T = D->getType(); 1090 1091 if (getLangOptions().CPlusPlus) { 1092 EmitCXXGlobalVarDeclInitFunc(D); 1093 Init = EmitNullConstant(T); 1094 NonConstInit = true; 1095 } else { 1096 ErrorUnsupported(D, "static initializer"); 1097 Init = llvm::UndefValue::get(getTypes().ConvertType(T)); 1098 } 1099 } else { 1100 // We don't need an initializer, so remove the entry for the delayed 1101 // initializer position (just in case this entry was delayed). 1102 if (getLangOptions().CPlusPlus) 1103 DelayedCXXInitPosition.erase(D); 1104 } 1105 } 1106 1107 const llvm::Type* InitType = Init->getType(); 1108 llvm::Constant *Entry = GetAddrOfGlobalVar(D, InitType); 1109 1110 // Strip off a bitcast if we got one back. 1111 if (llvm::ConstantExpr *CE = dyn_cast<llvm::ConstantExpr>(Entry)) { 1112 assert(CE->getOpcode() == llvm::Instruction::BitCast || 1113 // all zero index gep. 1114 CE->getOpcode() == llvm::Instruction::GetElementPtr); 1115 Entry = CE->getOperand(0); 1116 } 1117 1118 // Entry is now either a Function or GlobalVariable. 1119 llvm::GlobalVariable *GV = dyn_cast<llvm::GlobalVariable>(Entry); 1120 1121 // We have a definition after a declaration with the wrong type. 1122 // We must make a new GlobalVariable* and update everything that used OldGV 1123 // (a declaration or tentative definition) with the new GlobalVariable* 1124 // (which will be a definition). 1125 // 1126 // This happens if there is a prototype for a global (e.g. 1127 // "extern int x[];") and then a definition of a different type (e.g. 1128 // "int x[10];"). This also happens when an initializer has a different type 1129 // from the type of the global (this happens with unions). 1130 if (GV == 0 || 1131 GV->getType()->getElementType() != InitType || 1132 GV->getType()->getAddressSpace() != ASTTy.getAddressSpace()) { 1133 1134 // Move the old entry aside so that we'll create a new one. 1135 Entry->setName(llvm::StringRef()); 1136 1137 // Make a new global with the correct type, this is now guaranteed to work. 1138 GV = cast<llvm::GlobalVariable>(GetAddrOfGlobalVar(D, InitType)); 1139 1140 // Replace all uses of the old global with the new global 1141 llvm::Constant *NewPtrForOldDecl = 1142 llvm::ConstantExpr::getBitCast(GV, Entry->getType()); 1143 Entry->replaceAllUsesWith(NewPtrForOldDecl); 1144 1145 // Erase the old global, since it is no longer used. 1146 cast<llvm::GlobalValue>(Entry)->eraseFromParent(); 1147 } 1148 1149 if (const AnnotateAttr *AA = D->getAttr<AnnotateAttr>()) { 1150 SourceManager &SM = Context.getSourceManager(); 1151 AddAnnotation(EmitAnnotateAttr(GV, AA, 1152 SM.getInstantiationLineNumber(D->getLocation()))); 1153 } 1154 1155 GV->setInitializer(Init); 1156 1157 // If it is safe to mark the global 'constant', do so now. 1158 GV->setConstant(false); 1159 if (!NonConstInit && DeclIsConstantGlobal(Context, D)) 1160 GV->setConstant(true); 1161 1162 GV->setAlignment(getContext().getDeclAlign(D).getQuantity()); 1163 1164 // Set the llvm linkage type as appropriate. 1165 llvm::GlobalValue::LinkageTypes Linkage = 1166 GetLLVMLinkageVarDefinition(D, GV); 1167 GV->setLinkage(Linkage); 1168 if (Linkage == llvm::GlobalVariable::CommonLinkage) 1169 // common vars aren't constant even if declared const. 1170 GV->setConstant(false); 1171 1172 SetCommonAttributes(D, GV); 1173 1174 // Emit global variable debug information. 1175 if (CGDebugInfo *DI = getDebugInfo()) { 1176 DI->setLocation(D->getLocation()); 1177 DI->EmitGlobalVariable(GV, D); 1178 } 1179} 1180 1181llvm::GlobalValue::LinkageTypes 1182CodeGenModule::GetLLVMLinkageVarDefinition(const VarDecl *D, 1183 llvm::GlobalVariable *GV) { 1184 GVALinkage Linkage = getContext().GetGVALinkageForVariable(D); 1185 if (Linkage == GVA_Internal) 1186 return llvm::Function::InternalLinkage; 1187 else if (D->hasAttr<DLLImportAttr>()) 1188 return llvm::Function::DLLImportLinkage; 1189 else if (D->hasAttr<DLLExportAttr>()) 1190 return llvm::Function::DLLExportLinkage; 1191 else if (D->hasAttr<WeakAttr>()) { 1192 if (GV->isConstant()) 1193 return llvm::GlobalVariable::WeakODRLinkage; 1194 else 1195 return llvm::GlobalVariable::WeakAnyLinkage; 1196 } else if (Linkage == GVA_TemplateInstantiation || 1197 Linkage == GVA_ExplicitTemplateInstantiation) 1198 // FIXME: It seems like we can provide more specific linkage here 1199 // (LinkOnceODR, WeakODR). 1200 return llvm::GlobalVariable::WeakAnyLinkage; 1201 else if (!getLangOptions().CPlusPlus && !CodeGenOpts.NoCommon && 1202 !D->hasExternalStorage() && !D->getInit() && 1203 !D->getAttr<SectionAttr>() && !D->isThreadSpecified()) { 1204 // Thread local vars aren't considered common linkage. 1205 return llvm::GlobalVariable::CommonLinkage; 1206 } 1207 return llvm::GlobalVariable::ExternalLinkage; 1208} 1209 1210/// ReplaceUsesOfNonProtoTypeWithRealFunction - This function is called when we 1211/// implement a function with no prototype, e.g. "int foo() {}". If there are 1212/// existing call uses of the old function in the module, this adjusts them to 1213/// call the new function directly. 1214/// 1215/// This is not just a cleanup: the always_inline pass requires direct calls to 1216/// functions to be able to inline them. If there is a bitcast in the way, it 1217/// won't inline them. Instcombine normally deletes these calls, but it isn't 1218/// run at -O0. 1219static void ReplaceUsesOfNonProtoTypeWithRealFunction(llvm::GlobalValue *Old, 1220 llvm::Function *NewFn) { 1221 // If we're redefining a global as a function, don't transform it. 1222 llvm::Function *OldFn = dyn_cast<llvm::Function>(Old); 1223 if (OldFn == 0) return; 1224 1225 const llvm::Type *NewRetTy = NewFn->getReturnType(); 1226 llvm::SmallVector<llvm::Value*, 4> ArgList; 1227 1228 for (llvm::Value::use_iterator UI = OldFn->use_begin(), E = OldFn->use_end(); 1229 UI != E; ) { 1230 // TODO: Do invokes ever occur in C code? If so, we should handle them too. 1231 llvm::Value::use_iterator I = UI++; // Increment before the CI is erased. 1232 llvm::CallInst *CI = dyn_cast<llvm::CallInst>(*I); 1233 if (!CI) continue; // FIXME: when we allow Invoke, just do CallSite CS(*I) 1234 llvm::CallSite CS(CI); 1235 if (!CI || !CS.isCallee(I)) continue; 1236 1237 // If the return types don't match exactly, and if the call isn't dead, then 1238 // we can't transform this call. 1239 if (CI->getType() != NewRetTy && !CI->use_empty()) 1240 continue; 1241 1242 // If the function was passed too few arguments, don't transform. If extra 1243 // arguments were passed, we silently drop them. If any of the types 1244 // mismatch, we don't transform. 1245 unsigned ArgNo = 0; 1246 bool DontTransform = false; 1247 for (llvm::Function::arg_iterator AI = NewFn->arg_begin(), 1248 E = NewFn->arg_end(); AI != E; ++AI, ++ArgNo) { 1249 if (CS.arg_size() == ArgNo || 1250 CS.getArgument(ArgNo)->getType() != AI->getType()) { 1251 DontTransform = true; 1252 break; 1253 } 1254 } 1255 if (DontTransform) 1256 continue; 1257 1258 // Okay, we can transform this. Create the new call instruction and copy 1259 // over the required information. 1260 ArgList.append(CS.arg_begin(), CS.arg_begin() + ArgNo); 1261 llvm::CallInst *NewCall = llvm::CallInst::Create(NewFn, ArgList.begin(), 1262 ArgList.end(), "", CI); 1263 ArgList.clear(); 1264 if (!NewCall->getType()->isVoidTy()) 1265 NewCall->takeName(CI); 1266 NewCall->setAttributes(CI->getAttributes()); 1267 NewCall->setCallingConv(CI->getCallingConv()); 1268 1269 // Finally, remove the old call, replacing any uses with the new one. 1270 if (!CI->use_empty()) 1271 CI->replaceAllUsesWith(NewCall); 1272 1273 // Copy debug location attached to CI. 1274 if (!CI->getDebugLoc().isUnknown()) 1275 NewCall->setDebugLoc(CI->getDebugLoc()); 1276 CI->eraseFromParent(); 1277 } 1278} 1279 1280 1281void CodeGenModule::EmitGlobalFunctionDefinition(GlobalDecl GD) { 1282 const FunctionDecl *D = cast<FunctionDecl>(GD.getDecl()); 1283 const llvm::FunctionType *Ty = getTypes().GetFunctionType(GD); 1284 getCXXABI().getMangleContext().mangleInitDiscriminator(); 1285 // Get or create the prototype for the function. 1286 llvm::Constant *Entry = GetAddrOfFunction(GD, Ty); 1287 1288 // Strip off a bitcast if we got one back. 1289 if (llvm::ConstantExpr *CE = dyn_cast<llvm::ConstantExpr>(Entry)) { 1290 assert(CE->getOpcode() == llvm::Instruction::BitCast); 1291 Entry = CE->getOperand(0); 1292 } 1293 1294 1295 if (cast<llvm::GlobalValue>(Entry)->getType()->getElementType() != Ty) { 1296 llvm::GlobalValue *OldFn = cast<llvm::GlobalValue>(Entry); 1297 1298 // If the types mismatch then we have to rewrite the definition. 1299 assert(OldFn->isDeclaration() && 1300 "Shouldn't replace non-declaration"); 1301 1302 // F is the Function* for the one with the wrong type, we must make a new 1303 // Function* and update everything that used F (a declaration) with the new 1304 // Function* (which will be a definition). 1305 // 1306 // This happens if there is a prototype for a function 1307 // (e.g. "int f()") and then a definition of a different type 1308 // (e.g. "int f(int x)"). Move the old function aside so that it 1309 // doesn't interfere with GetAddrOfFunction. 1310 OldFn->setName(llvm::StringRef()); 1311 llvm::Function *NewFn = cast<llvm::Function>(GetAddrOfFunction(GD, Ty)); 1312 1313 // If this is an implementation of a function without a prototype, try to 1314 // replace any existing uses of the function (which may be calls) with uses 1315 // of the new function 1316 if (D->getType()->isFunctionNoProtoType()) { 1317 ReplaceUsesOfNonProtoTypeWithRealFunction(OldFn, NewFn); 1318 OldFn->removeDeadConstantUsers(); 1319 } 1320 1321 // Replace uses of F with the Function we will endow with a body. 1322 if (!Entry->use_empty()) { 1323 llvm::Constant *NewPtrForOldDecl = 1324 llvm::ConstantExpr::getBitCast(NewFn, Entry->getType()); 1325 Entry->replaceAllUsesWith(NewPtrForOldDecl); 1326 } 1327 1328 // Ok, delete the old function now, which is dead. 1329 OldFn->eraseFromParent(); 1330 1331 Entry = NewFn; 1332 } 1333 1334 llvm::Function *Fn = cast<llvm::Function>(Entry); 1335 setFunctionLinkage(D, Fn); 1336 1337 CodeGenFunction(*this).GenerateCode(D, Fn); 1338 1339 SetFunctionDefinitionAttributes(D, Fn); 1340 SetLLVMFunctionAttributesForDefinition(D, Fn); 1341 1342 if (const ConstructorAttr *CA = D->getAttr<ConstructorAttr>()) 1343 AddGlobalCtor(Fn, CA->getPriority()); 1344 if (const DestructorAttr *DA = D->getAttr<DestructorAttr>()) 1345 AddGlobalDtor(Fn, DA->getPriority()); 1346} 1347 1348void CodeGenModule::EmitAliasDefinition(GlobalDecl GD) { 1349 const ValueDecl *D = cast<ValueDecl>(GD.getDecl()); 1350 const AliasAttr *AA = D->getAttr<AliasAttr>(); 1351 assert(AA && "Not an alias?"); 1352 1353 llvm::StringRef MangledName = getMangledName(GD); 1354 1355 // If there is a definition in the module, then it wins over the alias. 1356 // This is dubious, but allow it to be safe. Just ignore the alias. 1357 llvm::GlobalValue *Entry = GetGlobalValue(MangledName); 1358 if (Entry && !Entry->isDeclaration()) 1359 return; 1360 1361 const llvm::Type *DeclTy = getTypes().ConvertTypeForMem(D->getType()); 1362 1363 // Create a reference to the named value. This ensures that it is emitted 1364 // if a deferred decl. 1365 llvm::Constant *Aliasee; 1366 if (isa<llvm::FunctionType>(DeclTy)) 1367 Aliasee = GetOrCreateLLVMFunction(AA->getAliasee(), DeclTy, GlobalDecl()); 1368 else 1369 Aliasee = GetOrCreateLLVMGlobal(AA->getAliasee(), 1370 llvm::PointerType::getUnqual(DeclTy), 0); 1371 1372 // Create the new alias itself, but don't set a name yet. 1373 llvm::GlobalValue *GA = 1374 new llvm::GlobalAlias(Aliasee->getType(), 1375 llvm::Function::ExternalLinkage, 1376 "", Aliasee, &getModule()); 1377 1378 if (Entry) { 1379 assert(Entry->isDeclaration()); 1380 1381 // If there is a declaration in the module, then we had an extern followed 1382 // by the alias, as in: 1383 // extern int test6(); 1384 // ... 1385 // int test6() __attribute__((alias("test7"))); 1386 // 1387 // Remove it and replace uses of it with the alias. 1388 GA->takeName(Entry); 1389 1390 Entry->replaceAllUsesWith(llvm::ConstantExpr::getBitCast(GA, 1391 Entry->getType())); 1392 Entry->eraseFromParent(); 1393 } else { 1394 GA->setName(MangledName); 1395 } 1396 1397 // Set attributes which are particular to an alias; this is a 1398 // specialization of the attributes which may be set on a global 1399 // variable/function. 1400 if (D->hasAttr<DLLExportAttr>()) { 1401 if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) { 1402 // The dllexport attribute is ignored for undefined symbols. 1403 if (FD->hasBody()) 1404 GA->setLinkage(llvm::Function::DLLExportLinkage); 1405 } else { 1406 GA->setLinkage(llvm::Function::DLLExportLinkage); 1407 } 1408 } else if (D->hasAttr<WeakAttr>() || 1409 D->hasAttr<WeakRefAttr>() || 1410 D->hasAttr<WeakImportAttr>()) { 1411 GA->setLinkage(llvm::Function::WeakAnyLinkage); 1412 } 1413 1414 SetCommonAttributes(D, GA); 1415} 1416 1417/// getBuiltinLibFunction - Given a builtin id for a function like 1418/// "__builtin_fabsf", return a Function* for "fabsf". 1419llvm::Value *CodeGenModule::getBuiltinLibFunction(const FunctionDecl *FD, 1420 unsigned BuiltinID) { 1421 assert((Context.BuiltinInfo.isLibFunction(BuiltinID) || 1422 Context.BuiltinInfo.isPredefinedLibFunction(BuiltinID)) && 1423 "isn't a lib fn"); 1424 1425 // Get the name, skip over the __builtin_ prefix (if necessary). 1426 const char *Name = Context.BuiltinInfo.GetName(BuiltinID); 1427 if (Context.BuiltinInfo.isLibFunction(BuiltinID)) 1428 Name += 10; 1429 1430 const llvm::FunctionType *Ty = 1431 cast<llvm::FunctionType>(getTypes().ConvertType(FD->getType())); 1432 1433 return GetOrCreateLLVMFunction(Name, Ty, GlobalDecl(FD)); 1434} 1435 1436llvm::Function *CodeGenModule::getIntrinsic(unsigned IID,const llvm::Type **Tys, 1437 unsigned NumTys) { 1438 return llvm::Intrinsic::getDeclaration(&getModule(), 1439 (llvm::Intrinsic::ID)IID, Tys, NumTys); 1440} 1441 1442 1443llvm::Function *CodeGenModule::getMemCpyFn(const llvm::Type *DestType, 1444 const llvm::Type *SrcType, 1445 const llvm::Type *SizeType) { 1446 const llvm::Type *ArgTypes[3] = {DestType, SrcType, SizeType }; 1447 return getIntrinsic(llvm::Intrinsic::memcpy, ArgTypes, 3); 1448} 1449 1450llvm::Function *CodeGenModule::getMemMoveFn(const llvm::Type *DestType, 1451 const llvm::Type *SrcType, 1452 const llvm::Type *SizeType) { 1453 const llvm::Type *ArgTypes[3] = {DestType, SrcType, SizeType }; 1454 return getIntrinsic(llvm::Intrinsic::memmove, ArgTypes, 3); 1455} 1456 1457llvm::Function *CodeGenModule::getMemSetFn(const llvm::Type *DestType, 1458 const llvm::Type *SizeType) { 1459 const llvm::Type *ArgTypes[2] = { DestType, SizeType }; 1460 return getIntrinsic(llvm::Intrinsic::memset, ArgTypes, 2); 1461} 1462 1463static llvm::StringMapEntry<llvm::Constant*> & 1464GetConstantCFStringEntry(llvm::StringMap<llvm::Constant*> &Map, 1465 const StringLiteral *Literal, 1466 bool TargetIsLSB, 1467 bool &IsUTF16, 1468 unsigned &StringLength) { 1469 llvm::StringRef String = Literal->getString(); 1470 unsigned NumBytes = String.size(); 1471 1472 // Check for simple case. 1473 if (!Literal->containsNonAsciiOrNull()) { 1474 StringLength = NumBytes; 1475 return Map.GetOrCreateValue(String); 1476 } 1477 1478 // Otherwise, convert the UTF8 literals into a byte string. 1479 llvm::SmallVector<UTF16, 128> ToBuf(NumBytes); 1480 const UTF8 *FromPtr = (UTF8 *)String.data(); 1481 UTF16 *ToPtr = &ToBuf[0]; 1482 1483 (void)ConvertUTF8toUTF16(&FromPtr, FromPtr + NumBytes, 1484 &ToPtr, ToPtr + NumBytes, 1485 strictConversion); 1486 1487 // ConvertUTF8toUTF16 returns the length in ToPtr. 1488 StringLength = ToPtr - &ToBuf[0]; 1489 1490 // Render the UTF-16 string into a byte array and convert to the target byte 1491 // order. 1492 // 1493 // FIXME: This isn't something we should need to do here. 1494 llvm::SmallString<128> AsBytes; 1495 AsBytes.reserve(StringLength * 2); 1496 for (unsigned i = 0; i != StringLength; ++i) { 1497 unsigned short Val = ToBuf[i]; 1498 if (TargetIsLSB) { 1499 AsBytes.push_back(Val & 0xFF); 1500 AsBytes.push_back(Val >> 8); 1501 } else { 1502 AsBytes.push_back(Val >> 8); 1503 AsBytes.push_back(Val & 0xFF); 1504 } 1505 } 1506 // Append one extra null character, the second is automatically added by our 1507 // caller. 1508 AsBytes.push_back(0); 1509 1510 IsUTF16 = true; 1511 return Map.GetOrCreateValue(llvm::StringRef(AsBytes.data(), AsBytes.size())); 1512} 1513 1514llvm::Constant * 1515CodeGenModule::GetAddrOfConstantCFString(const StringLiteral *Literal) { 1516 unsigned StringLength = 0; 1517 bool isUTF16 = false; 1518 llvm::StringMapEntry<llvm::Constant*> &Entry = 1519 GetConstantCFStringEntry(CFConstantStringMap, Literal, 1520 getTargetData().isLittleEndian(), 1521 isUTF16, StringLength); 1522 1523 if (llvm::Constant *C = Entry.getValue()) 1524 return C; 1525 1526 llvm::Constant *Zero = 1527 llvm::Constant::getNullValue(llvm::Type::getInt32Ty(VMContext)); 1528 llvm::Constant *Zeros[] = { Zero, Zero }; 1529 1530 // If we don't already have it, get __CFConstantStringClassReference. 1531 if (!CFConstantStringClassRef) { 1532 const llvm::Type *Ty = getTypes().ConvertType(getContext().IntTy); 1533 Ty = llvm::ArrayType::get(Ty, 0); 1534 llvm::Constant *GV = CreateRuntimeVariable(Ty, 1535 "__CFConstantStringClassReference"); 1536 // Decay array -> ptr 1537 CFConstantStringClassRef = 1538 llvm::ConstantExpr::getGetElementPtr(GV, Zeros, 2); 1539 } 1540 1541 QualType CFTy = getContext().getCFConstantStringType(); 1542 1543 const llvm::StructType *STy = 1544 cast<llvm::StructType>(getTypes().ConvertType(CFTy)); 1545 1546 std::vector<llvm::Constant*> Fields(4); 1547 1548 // Class pointer. 1549 Fields[0] = CFConstantStringClassRef; 1550 1551 // Flags. 1552 const llvm::Type *Ty = getTypes().ConvertType(getContext().UnsignedIntTy); 1553 Fields[1] = isUTF16 ? llvm::ConstantInt::get(Ty, 0x07d0) : 1554 llvm::ConstantInt::get(Ty, 0x07C8); 1555 1556 // String pointer. 1557 llvm::Constant *C = llvm::ConstantArray::get(VMContext, Entry.getKey().str()); 1558 1559 llvm::GlobalValue::LinkageTypes Linkage; 1560 bool isConstant; 1561 if (isUTF16) { 1562 // FIXME: why do utf strings get "_" labels instead of "L" labels? 1563 Linkage = llvm::GlobalValue::InternalLinkage; 1564 // Note: -fwritable-strings doesn't make unicode CFStrings writable, but 1565 // does make plain ascii ones writable. 1566 isConstant = true; 1567 } else { 1568 Linkage = llvm::GlobalValue::PrivateLinkage; 1569 isConstant = !Features.WritableStrings; 1570 } 1571 1572 llvm::GlobalVariable *GV = 1573 new llvm::GlobalVariable(getModule(), C->getType(), isConstant, Linkage, C, 1574 ".str"); 1575 if (isUTF16) { 1576 CharUnits Align = getContext().getTypeAlignInChars(getContext().ShortTy); 1577 GV->setAlignment(Align.getQuantity()); 1578 } 1579 Fields[2] = llvm::ConstantExpr::getGetElementPtr(GV, Zeros, 2); 1580 1581 // String length. 1582 Ty = getTypes().ConvertType(getContext().LongTy); 1583 Fields[3] = llvm::ConstantInt::get(Ty, StringLength); 1584 1585 // The struct. 1586 C = llvm::ConstantStruct::get(STy, Fields); 1587 GV = new llvm::GlobalVariable(getModule(), C->getType(), true, 1588 llvm::GlobalVariable::PrivateLinkage, C, 1589 "_unnamed_cfstring_"); 1590 if (const char *Sect = getContext().Target.getCFStringSection()) 1591 GV->setSection(Sect); 1592 Entry.setValue(GV); 1593 1594 return GV; 1595} 1596 1597llvm::Constant * 1598CodeGenModule::GetAddrOfConstantString(const StringLiteral *Literal) { 1599 unsigned StringLength = 0; 1600 bool isUTF16 = false; 1601 llvm::StringMapEntry<llvm::Constant*> &Entry = 1602 GetConstantCFStringEntry(CFConstantStringMap, Literal, 1603 getTargetData().isLittleEndian(), 1604 isUTF16, StringLength); 1605 1606 if (llvm::Constant *C = Entry.getValue()) 1607 return C; 1608 1609 llvm::Constant *Zero = 1610 llvm::Constant::getNullValue(llvm::Type::getInt32Ty(VMContext)); 1611 llvm::Constant *Zeros[] = { Zero, Zero }; 1612 1613 // If we don't already have it, get _NSConstantStringClassReference. 1614 if (!ConstantStringClassRef) { 1615 std::string StringClass(getLangOptions().ObjCConstantStringClass); 1616 const llvm::Type *Ty = getTypes().ConvertType(getContext().IntTy); 1617 Ty = llvm::ArrayType::get(Ty, 0); 1618 llvm::Constant *GV; 1619 if (StringClass.empty()) 1620 GV = CreateRuntimeVariable(Ty, 1621 Features.ObjCNonFragileABI ? 1622 "OBJC_CLASS_$_NSConstantString" : 1623 "_NSConstantStringClassReference"); 1624 else { 1625 std::string str; 1626 if (Features.ObjCNonFragileABI) 1627 str = "OBJC_CLASS_$_" + StringClass; 1628 else 1629 str = "_" + StringClass + "ClassReference"; 1630 GV = CreateRuntimeVariable(Ty, str); 1631 } 1632 // Decay array -> ptr 1633 ConstantStringClassRef = 1634 llvm::ConstantExpr::getGetElementPtr(GV, Zeros, 2); 1635 } 1636 1637 QualType NSTy = getContext().getNSConstantStringType(); 1638 1639 const llvm::StructType *STy = 1640 cast<llvm::StructType>(getTypes().ConvertType(NSTy)); 1641 1642 std::vector<llvm::Constant*> Fields(3); 1643 1644 // Class pointer. 1645 Fields[0] = ConstantStringClassRef; 1646 1647 // String pointer. 1648 llvm::Constant *C = llvm::ConstantArray::get(VMContext, Entry.getKey().str()); 1649 1650 llvm::GlobalValue::LinkageTypes Linkage; 1651 bool isConstant; 1652 if (isUTF16) { 1653 // FIXME: why do utf strings get "_" labels instead of "L" labels? 1654 Linkage = llvm::GlobalValue::InternalLinkage; 1655 // Note: -fwritable-strings doesn't make unicode NSStrings writable, but 1656 // does make plain ascii ones writable. 1657 isConstant = true; 1658 } else { 1659 Linkage = llvm::GlobalValue::PrivateLinkage; 1660 isConstant = !Features.WritableStrings; 1661 } 1662 1663 llvm::GlobalVariable *GV = 1664 new llvm::GlobalVariable(getModule(), C->getType(), isConstant, Linkage, C, 1665 ".str"); 1666 if (isUTF16) { 1667 CharUnits Align = getContext().getTypeAlignInChars(getContext().ShortTy); 1668 GV->setAlignment(Align.getQuantity()); 1669 } 1670 Fields[1] = llvm::ConstantExpr::getGetElementPtr(GV, Zeros, 2); 1671 1672 // String length. 1673 const llvm::Type *Ty = getTypes().ConvertType(getContext().UnsignedIntTy); 1674 Fields[2] = llvm::ConstantInt::get(Ty, StringLength); 1675 1676 // The struct. 1677 C = llvm::ConstantStruct::get(STy, Fields); 1678 GV = new llvm::GlobalVariable(getModule(), C->getType(), true, 1679 llvm::GlobalVariable::PrivateLinkage, C, 1680 "_unnamed_nsstring_"); 1681 // FIXME. Fix section. 1682 if (const char *Sect = 1683 Features.ObjCNonFragileABI 1684 ? getContext().Target.getNSStringNonFragileABISection() 1685 : getContext().Target.getNSStringSection()) 1686 GV->setSection(Sect); 1687 Entry.setValue(GV); 1688 1689 return GV; 1690} 1691 1692/// GetStringForStringLiteral - Return the appropriate bytes for a 1693/// string literal, properly padded to match the literal type. 1694std::string CodeGenModule::GetStringForStringLiteral(const StringLiteral *E) { 1695 const ConstantArrayType *CAT = 1696 getContext().getAsConstantArrayType(E->getType()); 1697 assert(CAT && "String isn't pointer or array!"); 1698 1699 // Resize the string to the right size. 1700 uint64_t RealLen = CAT->getSize().getZExtValue(); 1701 1702 if (E->isWide()) 1703 RealLen *= getContext().Target.getWCharWidth()/8; 1704 1705 std::string Str = E->getString().str(); 1706 Str.resize(RealLen, '\0'); 1707 1708 return Str; 1709} 1710 1711/// GetAddrOfConstantStringFromLiteral - Return a pointer to a 1712/// constant array for the given string literal. 1713llvm::Constant * 1714CodeGenModule::GetAddrOfConstantStringFromLiteral(const StringLiteral *S) { 1715 // FIXME: This can be more efficient. 1716 // FIXME: We shouldn't need to bitcast the constant in the wide string case. 1717 llvm::Constant *C = GetAddrOfConstantString(GetStringForStringLiteral(S)); 1718 if (S->isWide()) { 1719 llvm::Type *DestTy = 1720 llvm::PointerType::getUnqual(getTypes().ConvertType(S->getType())); 1721 C = llvm::ConstantExpr::getBitCast(C, DestTy); 1722 } 1723 return C; 1724} 1725 1726/// GetAddrOfConstantStringFromObjCEncode - Return a pointer to a constant 1727/// array for the given ObjCEncodeExpr node. 1728llvm::Constant * 1729CodeGenModule::GetAddrOfConstantStringFromObjCEncode(const ObjCEncodeExpr *E) { 1730 std::string Str; 1731 getContext().getObjCEncodingForType(E->getEncodedType(), Str); 1732 1733 return GetAddrOfConstantCString(Str); 1734} 1735 1736 1737/// GenerateWritableString -- Creates storage for a string literal. 1738static llvm::Constant *GenerateStringLiteral(const std::string &str, 1739 bool constant, 1740 CodeGenModule &CGM, 1741 const char *GlobalName) { 1742 // Create Constant for this string literal. Don't add a '\0'. 1743 llvm::Constant *C = 1744 llvm::ConstantArray::get(CGM.getLLVMContext(), str, false); 1745 1746 // Create a global variable for this string 1747 return new llvm::GlobalVariable(CGM.getModule(), C->getType(), constant, 1748 llvm::GlobalValue::PrivateLinkage, 1749 C, GlobalName); 1750} 1751 1752/// GetAddrOfConstantString - Returns a pointer to a character array 1753/// containing the literal. This contents are exactly that of the 1754/// given string, i.e. it will not be null terminated automatically; 1755/// see GetAddrOfConstantCString. Note that whether the result is 1756/// actually a pointer to an LLVM constant depends on 1757/// Feature.WriteableStrings. 1758/// 1759/// The result has pointer to array type. 1760llvm::Constant *CodeGenModule::GetAddrOfConstantString(const std::string &str, 1761 const char *GlobalName) { 1762 bool IsConstant = !Features.WritableStrings; 1763 1764 // Get the default prefix if a name wasn't specified. 1765 if (!GlobalName) 1766 GlobalName = ".str"; 1767 1768 // Don't share any string literals if strings aren't constant. 1769 if (!IsConstant) 1770 return GenerateStringLiteral(str, false, *this, GlobalName); 1771 1772 llvm::StringMapEntry<llvm::Constant *> &Entry = 1773 ConstantStringMap.GetOrCreateValue(&str[0], &str[str.length()]); 1774 1775 if (Entry.getValue()) 1776 return Entry.getValue(); 1777 1778 // Create a global variable for this. 1779 llvm::Constant *C = GenerateStringLiteral(str, true, *this, GlobalName); 1780 Entry.setValue(C); 1781 return C; 1782} 1783 1784/// GetAddrOfConstantCString - Returns a pointer to a character 1785/// array containing the literal and a terminating '\-' 1786/// character. The result has pointer to array type. 1787llvm::Constant *CodeGenModule::GetAddrOfConstantCString(const std::string &str, 1788 const char *GlobalName){ 1789 return GetAddrOfConstantString(str + '\0', GlobalName); 1790} 1791 1792/// EmitObjCPropertyImplementations - Emit information for synthesized 1793/// properties for an implementation. 1794void CodeGenModule::EmitObjCPropertyImplementations(const 1795 ObjCImplementationDecl *D) { 1796 for (ObjCImplementationDecl::propimpl_iterator 1797 i = D->propimpl_begin(), e = D->propimpl_end(); i != e; ++i) { 1798 ObjCPropertyImplDecl *PID = *i; 1799 1800 // Dynamic is just for type-checking. 1801 if (PID->getPropertyImplementation() == ObjCPropertyImplDecl::Synthesize) { 1802 ObjCPropertyDecl *PD = PID->getPropertyDecl(); 1803 1804 // Determine which methods need to be implemented, some may have 1805 // been overridden. Note that ::isSynthesized is not the method 1806 // we want, that just indicates if the decl came from a 1807 // property. What we want to know is if the method is defined in 1808 // this implementation. 1809 if (!D->getInstanceMethod(PD->getGetterName())) 1810 CodeGenFunction(*this).GenerateObjCGetter( 1811 const_cast<ObjCImplementationDecl *>(D), PID); 1812 if (!PD->isReadOnly() && 1813 !D->getInstanceMethod(PD->getSetterName())) 1814 CodeGenFunction(*this).GenerateObjCSetter( 1815 const_cast<ObjCImplementationDecl *>(D), PID); 1816 } 1817 } 1818} 1819 1820/// EmitObjCIvarInitializations - Emit information for ivar initialization 1821/// for an implementation. 1822void CodeGenModule::EmitObjCIvarInitializations(ObjCImplementationDecl *D) { 1823 if (!Features.NeXTRuntime || D->getNumIvarInitializers() == 0) 1824 return; 1825 DeclContext* DC = const_cast<DeclContext*>(dyn_cast<DeclContext>(D)); 1826 assert(DC && "EmitObjCIvarInitializations - null DeclContext"); 1827 IdentifierInfo *II = &getContext().Idents.get(".cxx_destruct"); 1828 Selector cxxSelector = getContext().Selectors.getSelector(0, &II); 1829 ObjCMethodDecl *DTORMethod = ObjCMethodDecl::Create(getContext(), 1830 D->getLocation(), 1831 D->getLocation(), cxxSelector, 1832 getContext().VoidTy, 0, 1833 DC, true, false, true, false, 1834 ObjCMethodDecl::Required); 1835 D->addInstanceMethod(DTORMethod); 1836 CodeGenFunction(*this).GenerateObjCCtorDtorMethod(D, DTORMethod, false); 1837 1838 II = &getContext().Idents.get(".cxx_construct"); 1839 cxxSelector = getContext().Selectors.getSelector(0, &II); 1840 // The constructor returns 'self'. 1841 ObjCMethodDecl *CTORMethod = ObjCMethodDecl::Create(getContext(), 1842 D->getLocation(), 1843 D->getLocation(), cxxSelector, 1844 getContext().getObjCIdType(), 0, 1845 DC, true, false, true, false, 1846 ObjCMethodDecl::Required); 1847 D->addInstanceMethod(CTORMethod); 1848 CodeGenFunction(*this).GenerateObjCCtorDtorMethod(D, CTORMethod, true); 1849 1850 1851} 1852 1853/// EmitNamespace - Emit all declarations in a namespace. 1854void CodeGenModule::EmitNamespace(const NamespaceDecl *ND) { 1855 for (RecordDecl::decl_iterator I = ND->decls_begin(), E = ND->decls_end(); 1856 I != E; ++I) 1857 EmitTopLevelDecl(*I); 1858} 1859 1860// EmitLinkageSpec - Emit all declarations in a linkage spec. 1861void CodeGenModule::EmitLinkageSpec(const LinkageSpecDecl *LSD) { 1862 if (LSD->getLanguage() != LinkageSpecDecl::lang_c && 1863 LSD->getLanguage() != LinkageSpecDecl::lang_cxx) { 1864 ErrorUnsupported(LSD, "linkage spec"); 1865 return; 1866 } 1867 1868 for (RecordDecl::decl_iterator I = LSD->decls_begin(), E = LSD->decls_end(); 1869 I != E; ++I) 1870 EmitTopLevelDecl(*I); 1871} 1872 1873/// EmitTopLevelDecl - Emit code for a single top level declaration. 1874void CodeGenModule::EmitTopLevelDecl(Decl *D) { 1875 // If an error has occurred, stop code generation, but continue 1876 // parsing and semantic analysis (to ensure all warnings and errors 1877 // are emitted). 1878 if (Diags.hasErrorOccurred()) 1879 return; 1880 1881 // Ignore dependent declarations. 1882 if (D->getDeclContext() && D->getDeclContext()->isDependentContext()) 1883 return; 1884 1885 switch (D->getKind()) { 1886 case Decl::CXXConversion: 1887 case Decl::CXXMethod: 1888 case Decl::Function: 1889 // Skip function templates 1890 if (cast<FunctionDecl>(D)->getDescribedFunctionTemplate()) 1891 return; 1892 1893 EmitGlobal(cast<FunctionDecl>(D)); 1894 break; 1895 1896 case Decl::Var: 1897 EmitGlobal(cast<VarDecl>(D)); 1898 break; 1899 1900 // C++ Decls 1901 case Decl::Namespace: 1902 EmitNamespace(cast<NamespaceDecl>(D)); 1903 break; 1904 // No code generation needed. 1905 case Decl::UsingShadow: 1906 case Decl::Using: 1907 case Decl::UsingDirective: 1908 case Decl::ClassTemplate: 1909 case Decl::FunctionTemplate: 1910 case Decl::NamespaceAlias: 1911 break; 1912 case Decl::CXXConstructor: 1913 // Skip function templates 1914 if (cast<FunctionDecl>(D)->getDescribedFunctionTemplate()) 1915 return; 1916 1917 EmitCXXConstructors(cast<CXXConstructorDecl>(D)); 1918 break; 1919 case Decl::CXXDestructor: 1920 EmitCXXDestructors(cast<CXXDestructorDecl>(D)); 1921 break; 1922 1923 case Decl::StaticAssert: 1924 // Nothing to do. 1925 break; 1926 1927 // Objective-C Decls 1928 1929 // Forward declarations, no (immediate) code generation. 1930 case Decl::ObjCClass: 1931 case Decl::ObjCForwardProtocol: 1932 case Decl::ObjCInterface: 1933 break; 1934 1935 case Decl::ObjCCategory: { 1936 ObjCCategoryDecl *CD = cast<ObjCCategoryDecl>(D); 1937 if (CD->IsClassExtension() && CD->hasSynthBitfield()) 1938 Context.ResetObjCLayout(CD->getClassInterface()); 1939 break; 1940 } 1941 1942 1943 case Decl::ObjCProtocol: 1944 Runtime->GenerateProtocol(cast<ObjCProtocolDecl>(D)); 1945 break; 1946 1947 case Decl::ObjCCategoryImpl: 1948 // Categories have properties but don't support synthesize so we 1949 // can ignore them here. 1950 Runtime->GenerateCategory(cast<ObjCCategoryImplDecl>(D)); 1951 break; 1952 1953 case Decl::ObjCImplementation: { 1954 ObjCImplementationDecl *OMD = cast<ObjCImplementationDecl>(D); 1955 if (Features.ObjCNonFragileABI2 && OMD->hasSynthBitfield()) 1956 Context.ResetObjCLayout(OMD->getClassInterface()); 1957 EmitObjCPropertyImplementations(OMD); 1958 EmitObjCIvarInitializations(OMD); 1959 Runtime->GenerateClass(OMD); 1960 break; 1961 } 1962 case Decl::ObjCMethod: { 1963 ObjCMethodDecl *OMD = cast<ObjCMethodDecl>(D); 1964 // If this is not a prototype, emit the body. 1965 if (OMD->getBody()) 1966 CodeGenFunction(*this).GenerateObjCMethod(OMD); 1967 break; 1968 } 1969 case Decl::ObjCCompatibleAlias: 1970 // compatibility-alias is a directive and has no code gen. 1971 break; 1972 1973 case Decl::LinkageSpec: 1974 EmitLinkageSpec(cast<LinkageSpecDecl>(D)); 1975 break; 1976 1977 case Decl::FileScopeAsm: { 1978 FileScopeAsmDecl *AD = cast<FileScopeAsmDecl>(D); 1979 llvm::StringRef AsmString = AD->getAsmString()->getString(); 1980 1981 const std::string &S = getModule().getModuleInlineAsm(); 1982 if (S.empty()) 1983 getModule().setModuleInlineAsm(AsmString); 1984 else 1985 getModule().setModuleInlineAsm(S + '\n' + AsmString.str()); 1986 break; 1987 } 1988 1989 default: 1990 // Make sure we handled everything we should, every other kind is a 1991 // non-top-level decl. FIXME: Would be nice to have an isTopLevelDeclKind 1992 // function. Need to recode Decl::Kind to do that easily. 1993 assert(isa<TypeDecl>(D) && "Unsupported decl kind"); 1994 } 1995} 1996 1997/// Turns the given pointer into a constant. 1998static llvm::Constant *GetPointerConstant(llvm::LLVMContext &Context, 1999 const void *Ptr) { 2000 uintptr_t PtrInt = reinterpret_cast<uintptr_t>(Ptr); 2001 const llvm::Type *i64 = llvm::Type::getInt64Ty(Context); 2002 return llvm::ConstantInt::get(i64, PtrInt); 2003} 2004 2005static void EmitGlobalDeclMetadata(CodeGenModule &CGM, 2006 llvm::NamedMDNode *&GlobalMetadata, 2007 GlobalDecl D, 2008 llvm::GlobalValue *Addr) { 2009 if (!GlobalMetadata) 2010 GlobalMetadata = 2011 CGM.getModule().getOrInsertNamedMetadata("clang.global.decl.ptrs"); 2012 2013 // TODO: should we report variant information for ctors/dtors? 2014 llvm::Value *Ops[] = { 2015 Addr, 2016 GetPointerConstant(CGM.getLLVMContext(), D.getDecl()) 2017 }; 2018 GlobalMetadata->addOperand(llvm::MDNode::get(CGM.getLLVMContext(), Ops, 2)); 2019} 2020 2021/// Emits metadata nodes associating all the global values in the 2022/// current module with the Decls they came from. This is useful for 2023/// projects using IR gen as a subroutine. 2024/// 2025/// Since there's currently no way to associate an MDNode directly 2026/// with an llvm::GlobalValue, we create a global named metadata 2027/// with the name 'clang.global.decl.ptrs'. 2028void CodeGenModule::EmitDeclMetadata() { 2029 llvm::NamedMDNode *GlobalMetadata = 0; 2030 2031 // StaticLocalDeclMap 2032 for (llvm::DenseMap<GlobalDecl,llvm::StringRef>::iterator 2033 I = MangledDeclNames.begin(), E = MangledDeclNames.end(); 2034 I != E; ++I) { 2035 llvm::GlobalValue *Addr = getModule().getNamedValue(I->second); 2036 EmitGlobalDeclMetadata(*this, GlobalMetadata, I->first, Addr); 2037 } 2038} 2039 2040/// Emits metadata nodes for all the local variables in the current 2041/// function. 2042void CodeGenFunction::EmitDeclMetadata() { 2043 if (LocalDeclMap.empty()) return; 2044 2045 llvm::LLVMContext &Context = getLLVMContext(); 2046 2047 // Find the unique metadata ID for this name. 2048 unsigned DeclPtrKind = Context.getMDKindID("clang.decl.ptr"); 2049 2050 llvm::NamedMDNode *GlobalMetadata = 0; 2051 2052 for (llvm::DenseMap<const Decl*, llvm::Value*>::iterator 2053 I = LocalDeclMap.begin(), E = LocalDeclMap.end(); I != E; ++I) { 2054 const Decl *D = I->first; 2055 llvm::Value *Addr = I->second; 2056 2057 if (llvm::AllocaInst *Alloca = dyn_cast<llvm::AllocaInst>(Addr)) { 2058 llvm::Value *DAddr = GetPointerConstant(getLLVMContext(), D); 2059 Alloca->setMetadata(DeclPtrKind, llvm::MDNode::get(Context, &DAddr, 1)); 2060 } else if (llvm::GlobalValue *GV = dyn_cast<llvm::GlobalValue>(Addr)) { 2061 GlobalDecl GD = GlobalDecl(cast<VarDecl>(D)); 2062 EmitGlobalDeclMetadata(CGM, GlobalMetadata, GD, GV); 2063 } 2064 } 2065} 2066 2067///@name Custom Runtime Function Interfaces 2068///@{ 2069// 2070// FIXME: These can be eliminated once we can have clients just get the required 2071// AST nodes from the builtin tables. 2072 2073llvm::Constant *CodeGenModule::getBlockObjectDispose() { 2074 if (BlockObjectDispose) 2075 return BlockObjectDispose; 2076 2077 // If we saw an explicit decl, use that. 2078 if (BlockObjectDisposeDecl) { 2079 return BlockObjectDispose = GetAddrOfFunction( 2080 BlockObjectDisposeDecl, 2081 getTypes().GetFunctionType(BlockObjectDisposeDecl)); 2082 } 2083 2084 // Otherwise construct the function by hand. 2085 const llvm::FunctionType *FTy; 2086 std::vector<const llvm::Type*> ArgTys; 2087 const llvm::Type *ResultType = llvm::Type::getVoidTy(VMContext); 2088 ArgTys.push_back(PtrToInt8Ty); 2089 ArgTys.push_back(llvm::Type::getInt32Ty(VMContext)); 2090 FTy = llvm::FunctionType::get(ResultType, ArgTys, false); 2091 return BlockObjectDispose = 2092 CreateRuntimeFunction(FTy, "_Block_object_dispose"); 2093} 2094 2095llvm::Constant *CodeGenModule::getBlockObjectAssign() { 2096 if (BlockObjectAssign) 2097 return BlockObjectAssign; 2098 2099 // If we saw an explicit decl, use that. 2100 if (BlockObjectAssignDecl) { 2101 return BlockObjectAssign = GetAddrOfFunction( 2102 BlockObjectAssignDecl, 2103 getTypes().GetFunctionType(BlockObjectAssignDecl)); 2104 } 2105 2106 // Otherwise construct the function by hand. 2107 const llvm::FunctionType *FTy; 2108 std::vector<const llvm::Type*> ArgTys; 2109 const llvm::Type *ResultType = llvm::Type::getVoidTy(VMContext); 2110 ArgTys.push_back(PtrToInt8Ty); 2111 ArgTys.push_back(PtrToInt8Ty); 2112 ArgTys.push_back(llvm::Type::getInt32Ty(VMContext)); 2113 FTy = llvm::FunctionType::get(ResultType, ArgTys, false); 2114 return BlockObjectAssign = 2115 CreateRuntimeFunction(FTy, "_Block_object_assign"); 2116} 2117 2118llvm::Constant *CodeGenModule::getNSConcreteGlobalBlock() { 2119 if (NSConcreteGlobalBlock) 2120 return NSConcreteGlobalBlock; 2121 2122 // If we saw an explicit decl, use that. 2123 if (NSConcreteGlobalBlockDecl) { 2124 return NSConcreteGlobalBlock = GetAddrOfGlobalVar( 2125 NSConcreteGlobalBlockDecl, 2126 getTypes().ConvertType(NSConcreteGlobalBlockDecl->getType())); 2127 } 2128 2129 // Otherwise construct the variable by hand. 2130 return NSConcreteGlobalBlock = CreateRuntimeVariable( 2131 PtrToInt8Ty, "_NSConcreteGlobalBlock"); 2132} 2133 2134llvm::Constant *CodeGenModule::getNSConcreteStackBlock() { 2135 if (NSConcreteStackBlock) 2136 return NSConcreteStackBlock; 2137 2138 // If we saw an explicit decl, use that. 2139 if (NSConcreteStackBlockDecl) { 2140 return NSConcreteStackBlock = GetAddrOfGlobalVar( 2141 NSConcreteStackBlockDecl, 2142 getTypes().ConvertType(NSConcreteStackBlockDecl->getType())); 2143 } 2144 2145 // Otherwise construct the variable by hand. 2146 return NSConcreteStackBlock = CreateRuntimeVariable( 2147 PtrToInt8Ty, "_NSConcreteStackBlock"); 2148} 2149 2150///@} 2151