CodeGenModule.cpp revision 3030eb82593097502469a8b3fc26112c79c75605
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, 180 bool IsForDefinition) const { 181 // Internal definitions always have default visibility. 182 if (GV->hasLocalLinkage()) { 183 GV->setVisibility(llvm::GlobalValue::DefaultVisibility); 184 return; 185 } 186 187 // Set visibility for definitions. 188 NamedDecl::LinkageInfo LV = D->getLinkageAndVisibility(); 189 if (LV.visibilityExplicit() || 190 (IsForDefinition && !GV->hasAvailableExternallyLinkage())) 191 GV->setVisibility(GetLLVMVisibility(LV.visibility())); 192} 193 194/// Set the symbol visibility of type information (vtable and RTTI) 195/// associated with the given type. 196void CodeGenModule::setTypeVisibility(llvm::GlobalValue *GV, 197 const CXXRecordDecl *RD, 198 bool IsForRTTI, 199 bool IsForDefinition) const { 200 setGlobalVisibility(GV, RD, IsForDefinition); 201 202 if (!CodeGenOpts.HiddenWeakVTables) 203 return; 204 205 // We want to drop the visibility to hidden for weak type symbols. 206 // This isn't possible if there might be unresolved references 207 // elsewhere that rely on this symbol being visible. 208 209 // This should be kept roughly in sync with setThunkVisibility 210 // in CGVTables.cpp. 211 212 // Preconditions. 213 if (GV->getLinkage() != llvm::GlobalVariable::WeakODRLinkage || 214 GV->getVisibility() != llvm::GlobalVariable::DefaultVisibility) 215 return; 216 217 // Don't override an explicit visibility attribute. 218 if (RD->hasAttr<VisibilityAttr>()) 219 return; 220 221 switch (RD->getTemplateSpecializationKind()) { 222 // We have to disable the optimization if this is an EI definition 223 // because there might be EI declarations in other shared objects. 224 case TSK_ExplicitInstantiationDefinition: 225 case TSK_ExplicitInstantiationDeclaration: 226 return; 227 228 // Every use of a non-template class's type information has to emit it. 229 case TSK_Undeclared: 230 break; 231 232 // In theory, implicit instantiations can ignore the possibility of 233 // an explicit instantiation declaration because there necessarily 234 // must be an EI definition somewhere with default visibility. In 235 // practice, it's possible to have an explicit instantiation for 236 // an arbitrary template class, and linkers aren't necessarily able 237 // to deal with mixed-visibility symbols. 238 case TSK_ExplicitSpecialization: 239 case TSK_ImplicitInstantiation: 240 if (!CodeGenOpts.HiddenWeakTemplateVTables) 241 return; 242 break; 243 } 244 245 // If there's a key function, there may be translation units 246 // that don't have the key function's definition. But ignore 247 // this if we're emitting RTTI under -fno-rtti. 248 if (!IsForRTTI || Features.RTTI) 249 if (Context.getKeyFunction(RD)) 250 return; 251 252 // Otherwise, drop the visibility to hidden. 253 GV->setVisibility(llvm::GlobalValue::HiddenVisibility); 254} 255 256llvm::StringRef CodeGenModule::getMangledName(GlobalDecl GD) { 257 const NamedDecl *ND = cast<NamedDecl>(GD.getDecl()); 258 259 llvm::StringRef &Str = MangledDeclNames[GD.getCanonicalDecl()]; 260 if (!Str.empty()) 261 return Str; 262 263 if (!getCXXABI().getMangleContext().shouldMangleDeclName(ND)) { 264 IdentifierInfo *II = ND->getIdentifier(); 265 assert(II && "Attempt to mangle unnamed decl."); 266 267 Str = II->getName(); 268 return Str; 269 } 270 271 llvm::SmallString<256> Buffer; 272 if (const CXXConstructorDecl *D = dyn_cast<CXXConstructorDecl>(ND)) 273 getCXXABI().getMangleContext().mangleCXXCtor(D, GD.getCtorType(), Buffer); 274 else if (const CXXDestructorDecl *D = dyn_cast<CXXDestructorDecl>(ND)) 275 getCXXABI().getMangleContext().mangleCXXDtor(D, GD.getDtorType(), Buffer); 276 else if (const BlockDecl *BD = dyn_cast<BlockDecl>(ND)) 277 getCXXABI().getMangleContext().mangleBlock(GD, BD, Buffer); 278 else 279 getCXXABI().getMangleContext().mangleName(ND, Buffer); 280 281 // Allocate space for the mangled name. 282 size_t Length = Buffer.size(); 283 char *Name = MangledNamesAllocator.Allocate<char>(Length); 284 std::copy(Buffer.begin(), Buffer.end(), Name); 285 286 Str = llvm::StringRef(Name, Length); 287 288 return Str; 289} 290 291void CodeGenModule::getMangledName(GlobalDecl GD, MangleBuffer &Buffer, 292 const BlockDecl *BD) { 293 getCXXABI().getMangleContext().mangleBlock(GD, BD, Buffer.getBuffer()); 294} 295 296llvm::GlobalValue *CodeGenModule::GetGlobalValue(llvm::StringRef Name) { 297 return getModule().getNamedValue(Name); 298} 299 300/// AddGlobalCtor - Add a function to the list that will be called before 301/// main() runs. 302void CodeGenModule::AddGlobalCtor(llvm::Function * Ctor, int Priority) { 303 // FIXME: Type coercion of void()* types. 304 GlobalCtors.push_back(std::make_pair(Ctor, Priority)); 305} 306 307/// AddGlobalDtor - Add a function to the list that will be called 308/// when the module is unloaded. 309void CodeGenModule::AddGlobalDtor(llvm::Function * Dtor, int Priority) { 310 // FIXME: Type coercion of void()* types. 311 GlobalDtors.push_back(std::make_pair(Dtor, Priority)); 312} 313 314void CodeGenModule::EmitCtorList(const CtorList &Fns, const char *GlobalName) { 315 // Ctor function type is void()*. 316 llvm::FunctionType* CtorFTy = 317 llvm::FunctionType::get(llvm::Type::getVoidTy(VMContext), 318 std::vector<const llvm::Type*>(), 319 false); 320 llvm::Type *CtorPFTy = llvm::PointerType::getUnqual(CtorFTy); 321 322 // Get the type of a ctor entry, { i32, void ()* }. 323 llvm::StructType* CtorStructTy = 324 llvm::StructType::get(VMContext, llvm::Type::getInt32Ty(VMContext), 325 llvm::PointerType::getUnqual(CtorFTy), NULL); 326 327 // Construct the constructor and destructor arrays. 328 std::vector<llvm::Constant*> Ctors; 329 for (CtorList::const_iterator I = Fns.begin(), E = Fns.end(); I != E; ++I) { 330 std::vector<llvm::Constant*> S; 331 S.push_back(llvm::ConstantInt::get(llvm::Type::getInt32Ty(VMContext), 332 I->second, false)); 333 S.push_back(llvm::ConstantExpr::getBitCast(I->first, CtorPFTy)); 334 Ctors.push_back(llvm::ConstantStruct::get(CtorStructTy, S)); 335 } 336 337 if (!Ctors.empty()) { 338 llvm::ArrayType *AT = llvm::ArrayType::get(CtorStructTy, Ctors.size()); 339 new llvm::GlobalVariable(TheModule, AT, false, 340 llvm::GlobalValue::AppendingLinkage, 341 llvm::ConstantArray::get(AT, Ctors), 342 GlobalName); 343 } 344} 345 346void CodeGenModule::EmitAnnotations() { 347 if (Annotations.empty()) 348 return; 349 350 // Create a new global variable for the ConstantStruct in the Module. 351 llvm::Constant *Array = 352 llvm::ConstantArray::get(llvm::ArrayType::get(Annotations[0]->getType(), 353 Annotations.size()), 354 Annotations); 355 llvm::GlobalValue *gv = 356 new llvm::GlobalVariable(TheModule, Array->getType(), false, 357 llvm::GlobalValue::AppendingLinkage, Array, 358 "llvm.global.annotations"); 359 gv->setSection("llvm.metadata"); 360} 361 362llvm::GlobalValue::LinkageTypes 363CodeGenModule::getFunctionLinkage(const FunctionDecl *D) { 364 GVALinkage Linkage = getContext().GetGVALinkageForFunction(D); 365 366 if (Linkage == GVA_Internal) 367 return llvm::Function::InternalLinkage; 368 369 if (D->hasAttr<DLLExportAttr>()) 370 return llvm::Function::DLLExportLinkage; 371 372 if (D->hasAttr<WeakAttr>()) 373 return llvm::Function::WeakAnyLinkage; 374 375 // In C99 mode, 'inline' functions are guaranteed to have a strong 376 // definition somewhere else, so we can use available_externally linkage. 377 if (Linkage == GVA_C99Inline) 378 return llvm::Function::AvailableExternallyLinkage; 379 380 // In C++, the compiler has to emit a definition in every translation unit 381 // that references the function. We should use linkonce_odr because 382 // a) if all references in this translation unit are optimized away, we 383 // don't need to codegen it. b) if the function persists, it needs to be 384 // merged with other definitions. c) C++ has the ODR, so we know the 385 // definition is dependable. 386 if (Linkage == GVA_CXXInline || Linkage == GVA_TemplateInstantiation) 387 return llvm::Function::LinkOnceODRLinkage; 388 389 // An explicit instantiation of a template has weak linkage, since 390 // explicit instantiations can occur in multiple translation units 391 // and must all be equivalent. However, we are not allowed to 392 // throw away these explicit instantiations. 393 if (Linkage == GVA_ExplicitTemplateInstantiation) 394 return llvm::Function::WeakODRLinkage; 395 396 // Otherwise, we have strong external linkage. 397 assert(Linkage == GVA_StrongExternal); 398 return llvm::Function::ExternalLinkage; 399} 400 401 402/// SetFunctionDefinitionAttributes - Set attributes for a global. 403/// 404/// FIXME: This is currently only done for aliases and functions, but not for 405/// variables (these details are set in EmitGlobalVarDefinition for variables). 406void CodeGenModule::SetFunctionDefinitionAttributes(const FunctionDecl *D, 407 llvm::GlobalValue *GV) { 408 SetCommonAttributes(D, GV); 409} 410 411void CodeGenModule::SetLLVMFunctionAttributes(const Decl *D, 412 const CGFunctionInfo &Info, 413 llvm::Function *F) { 414 unsigned CallingConv; 415 AttributeListType AttributeList; 416 ConstructAttributeList(Info, D, AttributeList, CallingConv); 417 F->setAttributes(llvm::AttrListPtr::get(AttributeList.begin(), 418 AttributeList.size())); 419 F->setCallingConv(static_cast<llvm::CallingConv::ID>(CallingConv)); 420} 421 422void CodeGenModule::SetLLVMFunctionAttributesForDefinition(const Decl *D, 423 llvm::Function *F) { 424 if (!Features.Exceptions && !Features.ObjCNonFragileABI) 425 F->addFnAttr(llvm::Attribute::NoUnwind); 426 427 if (D->hasAttr<AlwaysInlineAttr>()) 428 F->addFnAttr(llvm::Attribute::AlwaysInline); 429 430 if (D->hasAttr<NakedAttr>()) 431 F->addFnAttr(llvm::Attribute::Naked); 432 433 if (D->hasAttr<NoInlineAttr>()) 434 F->addFnAttr(llvm::Attribute::NoInline); 435 436 if (Features.getStackProtectorMode() == LangOptions::SSPOn) 437 F->addFnAttr(llvm::Attribute::StackProtect); 438 else if (Features.getStackProtectorMode() == LangOptions::SSPReq) 439 F->addFnAttr(llvm::Attribute::StackProtectReq); 440 441 unsigned alignment = D->getMaxAlignment() / Context.getCharWidth(); 442 if (alignment) 443 F->setAlignment(alignment); 444 445 // C++ ABI requires 2-byte alignment for member functions. 446 if (F->getAlignment() < 2 && isa<CXXMethodDecl>(D)) 447 F->setAlignment(2); 448} 449 450void CodeGenModule::SetCommonAttributes(const Decl *D, 451 llvm::GlobalValue *GV) { 452 if (isa<NamedDecl>(D)) 453 setGlobalVisibility(GV, cast<NamedDecl>(D), /*ForDef*/ true); 454 else 455 GV->setVisibility(llvm::GlobalValue::DefaultVisibility); 456 457 if (D->hasAttr<UsedAttr>()) 458 AddUsedGlobal(GV); 459 460 if (const SectionAttr *SA = D->getAttr<SectionAttr>()) 461 GV->setSection(SA->getName()); 462 463 getTargetCodeGenInfo().SetTargetAttributes(D, GV, *this); 464} 465 466void CodeGenModule::SetInternalFunctionAttributes(const Decl *D, 467 llvm::Function *F, 468 const CGFunctionInfo &FI) { 469 SetLLVMFunctionAttributes(D, FI, F); 470 SetLLVMFunctionAttributesForDefinition(D, F); 471 472 F->setLinkage(llvm::Function::InternalLinkage); 473 474 SetCommonAttributes(D, F); 475} 476 477void CodeGenModule::SetFunctionAttributes(GlobalDecl GD, 478 llvm::Function *F, 479 bool IsIncompleteFunction) { 480 const FunctionDecl *FD = cast<FunctionDecl>(GD.getDecl()); 481 482 if (!IsIncompleteFunction) 483 SetLLVMFunctionAttributes(FD, getTypes().getFunctionInfo(GD), F); 484 485 // Only a few attributes are set on declarations; these may later be 486 // overridden by a definition. 487 488 if (FD->hasAttr<DLLImportAttr>()) { 489 F->setLinkage(llvm::Function::DLLImportLinkage); 490 } else if (FD->hasAttr<WeakAttr>() || 491 FD->hasAttr<WeakImportAttr>()) { 492 // "extern_weak" is overloaded in LLVM; we probably should have 493 // separate linkage types for this. 494 F->setLinkage(llvm::Function::ExternalWeakLinkage); 495 } else { 496 F->setLinkage(llvm::Function::ExternalLinkage); 497 498 NamedDecl::LinkageInfo LV = FD->getLinkageAndVisibility(); 499 if (LV.linkage() == ExternalLinkage && LV.visibilityExplicit()) { 500 F->setVisibility(GetLLVMVisibility(LV.visibility())); 501 } 502 } 503 504 if (const SectionAttr *SA = FD->getAttr<SectionAttr>()) 505 F->setSection(SA->getName()); 506} 507 508void CodeGenModule::AddUsedGlobal(llvm::GlobalValue *GV) { 509 assert(!GV->isDeclaration() && 510 "Only globals with definition can force usage."); 511 LLVMUsed.push_back(GV); 512} 513 514void CodeGenModule::EmitLLVMUsed() { 515 // Don't create llvm.used if there is no need. 516 if (LLVMUsed.empty()) 517 return; 518 519 const llvm::Type *i8PTy = llvm::Type::getInt8PtrTy(VMContext); 520 521 // Convert LLVMUsed to what ConstantArray needs. 522 std::vector<llvm::Constant*> UsedArray; 523 UsedArray.resize(LLVMUsed.size()); 524 for (unsigned i = 0, e = LLVMUsed.size(); i != e; ++i) { 525 UsedArray[i] = 526 llvm::ConstantExpr::getBitCast(cast<llvm::Constant>(&*LLVMUsed[i]), 527 i8PTy); 528 } 529 530 if (UsedArray.empty()) 531 return; 532 llvm::ArrayType *ATy = llvm::ArrayType::get(i8PTy, UsedArray.size()); 533 534 llvm::GlobalVariable *GV = 535 new llvm::GlobalVariable(getModule(), ATy, false, 536 llvm::GlobalValue::AppendingLinkage, 537 llvm::ConstantArray::get(ATy, UsedArray), 538 "llvm.used"); 539 540 GV->setSection("llvm.metadata"); 541} 542 543void CodeGenModule::EmitDeferred() { 544 // Emit code for any potentially referenced deferred decls. Since a 545 // previously unused static decl may become used during the generation of code 546 // for a static function, iterate until no changes are made. 547 548 while (!DeferredDeclsToEmit.empty() || !DeferredVTables.empty()) { 549 if (!DeferredVTables.empty()) { 550 const CXXRecordDecl *RD = DeferredVTables.back(); 551 DeferredVTables.pop_back(); 552 getVTables().GenerateClassData(getVTableLinkage(RD), RD); 553 continue; 554 } 555 556 GlobalDecl D = DeferredDeclsToEmit.back(); 557 DeferredDeclsToEmit.pop_back(); 558 559 // Check to see if we've already emitted this. This is necessary 560 // for a couple of reasons: first, decls can end up in the 561 // deferred-decls queue multiple times, and second, decls can end 562 // up with definitions in unusual ways (e.g. by an extern inline 563 // function acquiring a strong function redefinition). Just 564 // ignore these cases. 565 // 566 // TODO: That said, looking this up multiple times is very wasteful. 567 llvm::StringRef Name = getMangledName(D); 568 llvm::GlobalValue *CGRef = GetGlobalValue(Name); 569 assert(CGRef && "Deferred decl wasn't referenced?"); 570 571 if (!CGRef->isDeclaration()) 572 continue; 573 574 // GlobalAlias::isDeclaration() defers to the aliasee, but for our 575 // purposes an alias counts as a definition. 576 if (isa<llvm::GlobalAlias>(CGRef)) 577 continue; 578 579 // Otherwise, emit the definition and move on to the next one. 580 EmitGlobalDefinition(D); 581 } 582} 583 584/// EmitAnnotateAttr - Generate the llvm::ConstantStruct which contains the 585/// annotation information for a given GlobalValue. The annotation struct is 586/// {i8 *, i8 *, i8 *, i32}. The first field is a constant expression, the 587/// GlobalValue being annotated. The second field is the constant string 588/// created from the AnnotateAttr's annotation. The third field is a constant 589/// string containing the name of the translation unit. The fourth field is 590/// the line number in the file of the annotated value declaration. 591/// 592/// FIXME: this does not unique the annotation string constants, as llvm-gcc 593/// appears to. 594/// 595llvm::Constant *CodeGenModule::EmitAnnotateAttr(llvm::GlobalValue *GV, 596 const AnnotateAttr *AA, 597 unsigned LineNo) { 598 llvm::Module *M = &getModule(); 599 600 // get [N x i8] constants for the annotation string, and the filename string 601 // which are the 2nd and 3rd elements of the global annotation structure. 602 const llvm::Type *SBP = llvm::Type::getInt8PtrTy(VMContext); 603 llvm::Constant *anno = llvm::ConstantArray::get(VMContext, 604 AA->getAnnotation(), true); 605 llvm::Constant *unit = llvm::ConstantArray::get(VMContext, 606 M->getModuleIdentifier(), 607 true); 608 609 // Get the two global values corresponding to the ConstantArrays we just 610 // created to hold the bytes of the strings. 611 llvm::GlobalValue *annoGV = 612 new llvm::GlobalVariable(*M, anno->getType(), false, 613 llvm::GlobalValue::PrivateLinkage, anno, 614 GV->getName()); 615 // translation unit name string, emitted into the llvm.metadata section. 616 llvm::GlobalValue *unitGV = 617 new llvm::GlobalVariable(*M, unit->getType(), false, 618 llvm::GlobalValue::PrivateLinkage, unit, 619 ".str"); 620 621 // Create the ConstantStruct for the global annotation. 622 llvm::Constant *Fields[4] = { 623 llvm::ConstantExpr::getBitCast(GV, SBP), 624 llvm::ConstantExpr::getBitCast(annoGV, SBP), 625 llvm::ConstantExpr::getBitCast(unitGV, SBP), 626 llvm::ConstantInt::get(llvm::Type::getInt32Ty(VMContext), LineNo) 627 }; 628 return llvm::ConstantStruct::get(VMContext, Fields, 4, false); 629} 630 631bool CodeGenModule::MayDeferGeneration(const ValueDecl *Global) { 632 // Never defer when EmitAllDecls is specified. 633 if (Features.EmitAllDecls) 634 return false; 635 636 return !getContext().DeclMustBeEmitted(Global); 637} 638 639llvm::Constant *CodeGenModule::GetWeakRefReference(const ValueDecl *VD) { 640 const AliasAttr *AA = VD->getAttr<AliasAttr>(); 641 assert(AA && "No alias?"); 642 643 const llvm::Type *DeclTy = getTypes().ConvertTypeForMem(VD->getType()); 644 645 // See if there is already something with the target's name in the module. 646 llvm::GlobalValue *Entry = GetGlobalValue(AA->getAliasee()); 647 648 llvm::Constant *Aliasee; 649 if (isa<llvm::FunctionType>(DeclTy)) 650 Aliasee = GetOrCreateLLVMFunction(AA->getAliasee(), DeclTy, GlobalDecl()); 651 else 652 Aliasee = GetOrCreateLLVMGlobal(AA->getAliasee(), 653 llvm::PointerType::getUnqual(DeclTy), 0); 654 if (!Entry) { 655 llvm::GlobalValue* F = cast<llvm::GlobalValue>(Aliasee); 656 F->setLinkage(llvm::Function::ExternalWeakLinkage); 657 WeakRefReferences.insert(F); 658 } 659 660 return Aliasee; 661} 662 663void CodeGenModule::EmitGlobal(GlobalDecl GD) { 664 const ValueDecl *Global = cast<ValueDecl>(GD.getDecl()); 665 666 // Weak references don't produce any output by themselves. 667 if (Global->hasAttr<WeakRefAttr>()) 668 return; 669 670 // If this is an alias definition (which otherwise looks like a declaration) 671 // emit it now. 672 if (Global->hasAttr<AliasAttr>()) 673 return EmitAliasDefinition(GD); 674 675 // Ignore declarations, they will be emitted on their first use. 676 if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(Global)) { 677 if (FD->getIdentifier()) { 678 llvm::StringRef Name = FD->getName(); 679 if (Name == "_Block_object_assign") { 680 BlockObjectAssignDecl = FD; 681 } else if (Name == "_Block_object_dispose") { 682 BlockObjectDisposeDecl = FD; 683 } 684 } 685 686 // Forward declarations are emitted lazily on first use. 687 if (!FD->isThisDeclarationADefinition()) 688 return; 689 } else { 690 const VarDecl *VD = cast<VarDecl>(Global); 691 assert(VD->isFileVarDecl() && "Cannot emit local var decl as global."); 692 693 if (VD->getIdentifier()) { 694 llvm::StringRef Name = VD->getName(); 695 if (Name == "_NSConcreteGlobalBlock") { 696 NSConcreteGlobalBlockDecl = VD; 697 } else if (Name == "_NSConcreteStackBlock") { 698 NSConcreteStackBlockDecl = VD; 699 } 700 } 701 702 703 if (VD->isThisDeclarationADefinition() != VarDecl::Definition) 704 return; 705 } 706 707 // Defer code generation when possible if this is a static definition, inline 708 // function etc. These we only want to emit if they are used. 709 if (!MayDeferGeneration(Global)) { 710 // Emit the definition if it can't be deferred. 711 EmitGlobalDefinition(GD); 712 return; 713 } 714 715 // If we're deferring emission of a C++ variable with an 716 // initializer, remember the order in which it appeared in the file. 717 if (getLangOptions().CPlusPlus && isa<VarDecl>(Global) && 718 cast<VarDecl>(Global)->hasInit()) { 719 DelayedCXXInitPosition[Global] = CXXGlobalInits.size(); 720 CXXGlobalInits.push_back(0); 721 } 722 723 // If the value has already been used, add it directly to the 724 // DeferredDeclsToEmit list. 725 llvm::StringRef MangledName = getMangledName(GD); 726 if (GetGlobalValue(MangledName)) 727 DeferredDeclsToEmit.push_back(GD); 728 else { 729 // Otherwise, remember that we saw a deferred decl with this name. The 730 // first use of the mangled name will cause it to move into 731 // DeferredDeclsToEmit. 732 DeferredDecls[MangledName] = GD; 733 } 734} 735 736void CodeGenModule::EmitGlobalDefinition(GlobalDecl GD) { 737 const ValueDecl *D = cast<ValueDecl>(GD.getDecl()); 738 739 PrettyStackTraceDecl CrashInfo(const_cast<ValueDecl *>(D), D->getLocation(), 740 Context.getSourceManager(), 741 "Generating code for declaration"); 742 743 if (const FunctionDecl *Function = dyn_cast<FunctionDecl>(D)) { 744 // At -O0, don't generate IR for functions with available_externally 745 // linkage. 746 if (CodeGenOpts.OptimizationLevel == 0 && 747 !Function->hasAttr<AlwaysInlineAttr>() && 748 getFunctionLinkage(Function) 749 == llvm::Function::AvailableExternallyLinkage) 750 return; 751 752 if (const CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(D)) { 753 if (Method->isVirtual()) 754 getVTables().EmitThunks(GD); 755 756 if (const CXXConstructorDecl *CD = dyn_cast<CXXConstructorDecl>(Method)) 757 return EmitCXXConstructor(CD, GD.getCtorType()); 758 759 if (const CXXDestructorDecl *DD = dyn_cast<CXXDestructorDecl>(Method)) 760 return EmitCXXDestructor(DD, GD.getDtorType()); 761 } 762 763 return EmitGlobalFunctionDefinition(GD); 764 } 765 766 if (const VarDecl *VD = dyn_cast<VarDecl>(D)) 767 return EmitGlobalVarDefinition(VD); 768 769 assert(0 && "Invalid argument to EmitGlobalDefinition()"); 770} 771 772/// GetOrCreateLLVMFunction - If the specified mangled name is not in the 773/// module, create and return an llvm Function with the specified type. If there 774/// is something in the module with the specified name, return it potentially 775/// bitcasted to the right type. 776/// 777/// If D is non-null, it specifies a decl that correspond to this. This is used 778/// to set the attributes on the function when it is first created. 779llvm::Constant * 780CodeGenModule::GetOrCreateLLVMFunction(llvm::StringRef MangledName, 781 const llvm::Type *Ty, 782 GlobalDecl D) { 783 // Lookup the entry, lazily creating it if necessary. 784 llvm::GlobalValue *Entry = GetGlobalValue(MangledName); 785 if (Entry) { 786 if (WeakRefReferences.count(Entry)) { 787 const FunctionDecl *FD = cast_or_null<FunctionDecl>(D.getDecl()); 788 if (FD && !FD->hasAttr<WeakAttr>()) 789 Entry->setLinkage(llvm::Function::ExternalLinkage); 790 791 WeakRefReferences.erase(Entry); 792 } 793 794 if (Entry->getType()->getElementType() == Ty) 795 return Entry; 796 797 // Make sure the result is of the correct type. 798 const llvm::Type *PTy = llvm::PointerType::getUnqual(Ty); 799 return llvm::ConstantExpr::getBitCast(Entry, PTy); 800 } 801 802 // This function doesn't have a complete type (for example, the return 803 // type is an incomplete struct). Use a fake type instead, and make 804 // sure not to try to set attributes. 805 bool IsIncompleteFunction = false; 806 807 const llvm::FunctionType *FTy; 808 if (isa<llvm::FunctionType>(Ty)) { 809 FTy = cast<llvm::FunctionType>(Ty); 810 } else { 811 FTy = llvm::FunctionType::get(llvm::Type::getVoidTy(VMContext), 812 std::vector<const llvm::Type*>(), false); 813 IsIncompleteFunction = true; 814 } 815 816 llvm::Function *F = llvm::Function::Create(FTy, 817 llvm::Function::ExternalLinkage, 818 MangledName, &getModule()); 819 assert(F->getName() == MangledName && "name was uniqued!"); 820 if (D.getDecl()) 821 SetFunctionAttributes(D, F, IsIncompleteFunction); 822 823 // This is the first use or definition of a mangled name. If there is a 824 // deferred decl with this name, remember that we need to emit it at the end 825 // of the file. 826 llvm::StringMap<GlobalDecl>::iterator DDI = DeferredDecls.find(MangledName); 827 if (DDI != DeferredDecls.end()) { 828 // Move the potentially referenced deferred decl to the DeferredDeclsToEmit 829 // list, and remove it from DeferredDecls (since we don't need it anymore). 830 DeferredDeclsToEmit.push_back(DDI->second); 831 DeferredDecls.erase(DDI); 832 } else if (const FunctionDecl *FD = cast_or_null<FunctionDecl>(D.getDecl())) { 833 // If this the first reference to a C++ inline function in a class, queue up 834 // the deferred function body for emission. These are not seen as 835 // top-level declarations. 836 if (FD->isThisDeclarationADefinition() && MayDeferGeneration(FD)) { 837 DeferredDeclsToEmit.push_back(D); 838 // A called constructor which has no definition or declaration need be 839 // synthesized. 840 } else if (const CXXConstructorDecl *CD = dyn_cast<CXXConstructorDecl>(FD)) { 841 if (CD->isImplicit()) { 842 assert(CD->isUsed() && "Sema doesn't consider constructor as used."); 843 DeferredDeclsToEmit.push_back(D); 844 } 845 } else if (const CXXDestructorDecl *DD = dyn_cast<CXXDestructorDecl>(FD)) { 846 if (DD->isImplicit()) { 847 assert(DD->isUsed() && "Sema doesn't consider destructor as used."); 848 DeferredDeclsToEmit.push_back(D); 849 } 850 } else if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(FD)) { 851 if (MD->isImplicit() && MD->isCopyAssignmentOperator()) { 852 assert(MD->isUsed() && "Sema doesn't consider CopyAssignment as used."); 853 DeferredDeclsToEmit.push_back(D); 854 } 855 } 856 } 857 858 // Make sure the result is of the requested type. 859 if (!IsIncompleteFunction) { 860 assert(F->getType()->getElementType() == Ty); 861 return F; 862 } 863 864 const llvm::Type *PTy = llvm::PointerType::getUnqual(Ty); 865 return llvm::ConstantExpr::getBitCast(F, PTy); 866} 867 868/// GetAddrOfFunction - Return the address of the given function. If Ty is 869/// non-null, then this function will use the specified type if it has to 870/// create it (this occurs when we see a definition of the function). 871llvm::Constant *CodeGenModule::GetAddrOfFunction(GlobalDecl GD, 872 const llvm::Type *Ty) { 873 // If there was no specific requested type, just convert it now. 874 if (!Ty) 875 Ty = getTypes().ConvertType(cast<ValueDecl>(GD.getDecl())->getType()); 876 877 llvm::StringRef MangledName = getMangledName(GD); 878 return GetOrCreateLLVMFunction(MangledName, Ty, GD); 879} 880 881/// CreateRuntimeFunction - Create a new runtime function with the specified 882/// type and name. 883llvm::Constant * 884CodeGenModule::CreateRuntimeFunction(const llvm::FunctionType *FTy, 885 llvm::StringRef Name) { 886 return GetOrCreateLLVMFunction(Name, FTy, GlobalDecl()); 887} 888 889static bool DeclIsConstantGlobal(ASTContext &Context, const VarDecl *D) { 890 if (!D->getType().isConstant(Context) && !D->getType()->isReferenceType()) 891 return false; 892 if (Context.getLangOptions().CPlusPlus && 893 Context.getBaseElementType(D->getType())->getAs<RecordType>()) { 894 // FIXME: We should do something fancier here! 895 return false; 896 } 897 return true; 898} 899 900/// GetOrCreateLLVMGlobal - If the specified mangled name is not in the module, 901/// create and return an llvm GlobalVariable with the specified type. If there 902/// is something in the module with the specified name, return it potentially 903/// bitcasted to the right type. 904/// 905/// If D is non-null, it specifies a decl that correspond to this. This is used 906/// to set the attributes on the global when it is first created. 907llvm::Constant * 908CodeGenModule::GetOrCreateLLVMGlobal(llvm::StringRef MangledName, 909 const llvm::PointerType *Ty, 910 const VarDecl *D) { 911 // Lookup the entry, lazily creating it if necessary. 912 llvm::GlobalValue *Entry = GetGlobalValue(MangledName); 913 if (Entry) { 914 if (WeakRefReferences.count(Entry)) { 915 if (D && !D->hasAttr<WeakAttr>()) 916 Entry->setLinkage(llvm::Function::ExternalLinkage); 917 918 WeakRefReferences.erase(Entry); 919 } 920 921 if (Entry->getType() == Ty) 922 return Entry; 923 924 // Make sure the result is of the correct type. 925 return llvm::ConstantExpr::getBitCast(Entry, Ty); 926 } 927 928 // This is the first use or definition of a mangled name. If there is a 929 // deferred decl with this name, remember that we need to emit it at the end 930 // of the file. 931 llvm::StringMap<GlobalDecl>::iterator DDI = DeferredDecls.find(MangledName); 932 if (DDI != DeferredDecls.end()) { 933 // Move the potentially referenced deferred decl to the DeferredDeclsToEmit 934 // list, and remove it from DeferredDecls (since we don't need it anymore). 935 DeferredDeclsToEmit.push_back(DDI->second); 936 DeferredDecls.erase(DDI); 937 } 938 939 llvm::GlobalVariable *GV = 940 new llvm::GlobalVariable(getModule(), Ty->getElementType(), false, 941 llvm::GlobalValue::ExternalLinkage, 942 0, MangledName, 0, 943 false, Ty->getAddressSpace()); 944 945 // Handle things which are present even on external declarations. 946 if (D) { 947 // FIXME: This code is overly simple and should be merged with other global 948 // handling. 949 GV->setConstant(DeclIsConstantGlobal(Context, D)); 950 951 // Set linkage and visibility in case we never see a definition. 952 NamedDecl::LinkageInfo LV = D->getLinkageAndVisibility(); 953 if (LV.linkage() != ExternalLinkage) { 954 GV->setLinkage(llvm::GlobalValue::InternalLinkage); 955 } else { 956 if (D->hasAttr<DLLImportAttr>()) 957 GV->setLinkage(llvm::GlobalValue::DLLImportLinkage); 958 else if (D->hasAttr<WeakAttr>() || D->hasAttr<WeakImportAttr>()) 959 GV->setLinkage(llvm::GlobalValue::ExternalWeakLinkage); 960 961 // Set visibility on a declaration only if it's explicit. 962 if (LV.visibilityExplicit()) 963 GV->setVisibility(GetLLVMVisibility(LV.visibility())); 964 } 965 966 GV->setThreadLocal(D->isThreadSpecified()); 967 } 968 969 return GV; 970} 971 972 973/// GetAddrOfGlobalVar - Return the llvm::Constant for the address of the 974/// given global variable. If Ty is non-null and if the global doesn't exist, 975/// then it will be greated with the specified type instead of whatever the 976/// normal requested type would be. 977llvm::Constant *CodeGenModule::GetAddrOfGlobalVar(const VarDecl *D, 978 const llvm::Type *Ty) { 979 assert(D->hasGlobalStorage() && "Not a global variable"); 980 QualType ASTTy = D->getType(); 981 if (Ty == 0) 982 Ty = getTypes().ConvertTypeForMem(ASTTy); 983 984 const llvm::PointerType *PTy = 985 llvm::PointerType::get(Ty, ASTTy.getAddressSpace()); 986 987 llvm::StringRef MangledName = getMangledName(D); 988 return GetOrCreateLLVMGlobal(MangledName, PTy, D); 989} 990 991/// CreateRuntimeVariable - Create a new runtime global variable with the 992/// specified type and name. 993llvm::Constant * 994CodeGenModule::CreateRuntimeVariable(const llvm::Type *Ty, 995 llvm::StringRef Name) { 996 return GetOrCreateLLVMGlobal(Name, llvm::PointerType::getUnqual(Ty), 0); 997} 998 999void CodeGenModule::EmitTentativeDefinition(const VarDecl *D) { 1000 assert(!D->getInit() && "Cannot emit definite definitions here!"); 1001 1002 if (MayDeferGeneration(D)) { 1003 // If we have not seen a reference to this variable yet, place it 1004 // into the deferred declarations table to be emitted if needed 1005 // later. 1006 llvm::StringRef MangledName = getMangledName(D); 1007 if (!GetGlobalValue(MangledName)) { 1008 DeferredDecls[MangledName] = D; 1009 return; 1010 } 1011 } 1012 1013 // The tentative definition is the only definition. 1014 EmitGlobalVarDefinition(D); 1015} 1016 1017void CodeGenModule::EmitVTable(CXXRecordDecl *Class, bool DefinitionRequired) { 1018 if (DefinitionRequired) 1019 getVTables().GenerateClassData(getVTableLinkage(Class), Class); 1020} 1021 1022llvm::GlobalVariable::LinkageTypes 1023CodeGenModule::getVTableLinkage(const CXXRecordDecl *RD) { 1024 if (RD->isInAnonymousNamespace() || !RD->hasLinkage()) 1025 return llvm::GlobalVariable::InternalLinkage; 1026 1027 if (const CXXMethodDecl *KeyFunction 1028 = RD->getASTContext().getKeyFunction(RD)) { 1029 // If this class has a key function, use that to determine the linkage of 1030 // the vtable. 1031 const FunctionDecl *Def = 0; 1032 if (KeyFunction->hasBody(Def)) 1033 KeyFunction = cast<CXXMethodDecl>(Def); 1034 1035 switch (KeyFunction->getTemplateSpecializationKind()) { 1036 case TSK_Undeclared: 1037 case TSK_ExplicitSpecialization: 1038 if (KeyFunction->isInlined()) 1039 return llvm::GlobalVariable::WeakODRLinkage; 1040 1041 return llvm::GlobalVariable::ExternalLinkage; 1042 1043 case TSK_ImplicitInstantiation: 1044 case TSK_ExplicitInstantiationDefinition: 1045 return llvm::GlobalVariable::WeakODRLinkage; 1046 1047 case TSK_ExplicitInstantiationDeclaration: 1048 // FIXME: Use available_externally linkage. However, this currently 1049 // breaks LLVM's build due to undefined symbols. 1050 // return llvm::GlobalVariable::AvailableExternallyLinkage; 1051 return llvm::GlobalVariable::WeakODRLinkage; 1052 } 1053 } 1054 1055 switch (RD->getTemplateSpecializationKind()) { 1056 case TSK_Undeclared: 1057 case TSK_ExplicitSpecialization: 1058 case TSK_ImplicitInstantiation: 1059 case TSK_ExplicitInstantiationDefinition: 1060 return llvm::GlobalVariable::WeakODRLinkage; 1061 1062 case TSK_ExplicitInstantiationDeclaration: 1063 // FIXME: Use available_externally linkage. However, this currently 1064 // breaks LLVM's build due to undefined symbols. 1065 // return llvm::GlobalVariable::AvailableExternallyLinkage; 1066 return llvm::GlobalVariable::WeakODRLinkage; 1067 } 1068 1069 // Silence GCC warning. 1070 return llvm::GlobalVariable::WeakODRLinkage; 1071} 1072 1073CharUnits CodeGenModule::GetTargetTypeStoreSize(const llvm::Type *Ty) const { 1074 return CharUnits::fromQuantity( 1075 TheTargetData.getTypeStoreSizeInBits(Ty) / Context.getCharWidth()); 1076} 1077 1078void CodeGenModule::EmitGlobalVarDefinition(const VarDecl *D) { 1079 llvm::Constant *Init = 0; 1080 QualType ASTTy = D->getType(); 1081 bool NonConstInit = false; 1082 1083 const Expr *InitExpr = D->getAnyInitializer(); 1084 1085 if (!InitExpr) { 1086 // This is a tentative definition; tentative definitions are 1087 // implicitly initialized with { 0 }. 1088 // 1089 // Note that tentative definitions are only emitted at the end of 1090 // a translation unit, so they should never have incomplete 1091 // type. In addition, EmitTentativeDefinition makes sure that we 1092 // never attempt to emit a tentative definition if a real one 1093 // exists. A use may still exists, however, so we still may need 1094 // to do a RAUW. 1095 assert(!ASTTy->isIncompleteType() && "Unexpected incomplete type"); 1096 Init = EmitNullConstant(D->getType()); 1097 } else { 1098 Init = EmitConstantExpr(InitExpr, D->getType()); 1099 if (!Init) { 1100 QualType T = InitExpr->getType(); 1101 if (D->getType()->isReferenceType()) 1102 T = D->getType(); 1103 1104 if (getLangOptions().CPlusPlus) { 1105 Init = EmitNullConstant(T); 1106 NonConstInit = true; 1107 } else { 1108 ErrorUnsupported(D, "static initializer"); 1109 Init = llvm::UndefValue::get(getTypes().ConvertType(T)); 1110 } 1111 } else { 1112 // We don't need an initializer, so remove the entry for the delayed 1113 // initializer position (just in case this entry was delayed). 1114 if (getLangOptions().CPlusPlus) 1115 DelayedCXXInitPosition.erase(D); 1116 } 1117 } 1118 1119 const llvm::Type* InitType = Init->getType(); 1120 llvm::Constant *Entry = GetAddrOfGlobalVar(D, InitType); 1121 1122 // Strip off a bitcast if we got one back. 1123 if (llvm::ConstantExpr *CE = dyn_cast<llvm::ConstantExpr>(Entry)) { 1124 assert(CE->getOpcode() == llvm::Instruction::BitCast || 1125 // all zero index gep. 1126 CE->getOpcode() == llvm::Instruction::GetElementPtr); 1127 Entry = CE->getOperand(0); 1128 } 1129 1130 // Entry is now either a Function or GlobalVariable. 1131 llvm::GlobalVariable *GV = dyn_cast<llvm::GlobalVariable>(Entry); 1132 1133 // We have a definition after a declaration with the wrong type. 1134 // We must make a new GlobalVariable* and update everything that used OldGV 1135 // (a declaration or tentative definition) with the new GlobalVariable* 1136 // (which will be a definition). 1137 // 1138 // This happens if there is a prototype for a global (e.g. 1139 // "extern int x[];") and then a definition of a different type (e.g. 1140 // "int x[10];"). This also happens when an initializer has a different type 1141 // from the type of the global (this happens with unions). 1142 if (GV == 0 || 1143 GV->getType()->getElementType() != InitType || 1144 GV->getType()->getAddressSpace() != ASTTy.getAddressSpace()) { 1145 1146 // Move the old entry aside so that we'll create a new one. 1147 Entry->setName(llvm::StringRef()); 1148 1149 // Make a new global with the correct type, this is now guaranteed to work. 1150 GV = cast<llvm::GlobalVariable>(GetAddrOfGlobalVar(D, InitType)); 1151 1152 // Replace all uses of the old global with the new global 1153 llvm::Constant *NewPtrForOldDecl = 1154 llvm::ConstantExpr::getBitCast(GV, Entry->getType()); 1155 Entry->replaceAllUsesWith(NewPtrForOldDecl); 1156 1157 // Erase the old global, since it is no longer used. 1158 cast<llvm::GlobalValue>(Entry)->eraseFromParent(); 1159 } 1160 1161 if (const AnnotateAttr *AA = D->getAttr<AnnotateAttr>()) { 1162 SourceManager &SM = Context.getSourceManager(); 1163 AddAnnotation(EmitAnnotateAttr(GV, AA, 1164 SM.getInstantiationLineNumber(D->getLocation()))); 1165 } 1166 1167 GV->setInitializer(Init); 1168 1169 // If it is safe to mark the global 'constant', do so now. 1170 GV->setConstant(false); 1171 if (!NonConstInit && DeclIsConstantGlobal(Context, D)) 1172 GV->setConstant(true); 1173 1174 GV->setAlignment(getContext().getDeclAlign(D).getQuantity()); 1175 1176 // Set the llvm linkage type as appropriate. 1177 llvm::GlobalValue::LinkageTypes Linkage = 1178 GetLLVMLinkageVarDefinition(D, GV); 1179 GV->setLinkage(Linkage); 1180 if (Linkage == llvm::GlobalVariable::CommonLinkage) 1181 // common vars aren't constant even if declared const. 1182 GV->setConstant(false); 1183 1184 SetCommonAttributes(D, GV); 1185 1186 // Emit the initializer function if necessary. 1187 if (NonConstInit) 1188 EmitCXXGlobalVarDeclInitFunc(D, GV); 1189 1190 // Emit global variable debug information. 1191 if (CGDebugInfo *DI = getDebugInfo()) { 1192 DI->setLocation(D->getLocation()); 1193 DI->EmitGlobalVariable(GV, D); 1194 } 1195} 1196 1197llvm::GlobalValue::LinkageTypes 1198CodeGenModule::GetLLVMLinkageVarDefinition(const VarDecl *D, 1199 llvm::GlobalVariable *GV) { 1200 GVALinkage Linkage = getContext().GetGVALinkageForVariable(D); 1201 if (Linkage == GVA_Internal) 1202 return llvm::Function::InternalLinkage; 1203 else if (D->hasAttr<DLLImportAttr>()) 1204 return llvm::Function::DLLImportLinkage; 1205 else if (D->hasAttr<DLLExportAttr>()) 1206 return llvm::Function::DLLExportLinkage; 1207 else if (D->hasAttr<WeakAttr>()) { 1208 if (GV->isConstant()) 1209 return llvm::GlobalVariable::WeakODRLinkage; 1210 else 1211 return llvm::GlobalVariable::WeakAnyLinkage; 1212 } else if (Linkage == GVA_TemplateInstantiation || 1213 Linkage == GVA_ExplicitTemplateInstantiation) 1214 // FIXME: It seems like we can provide more specific linkage here 1215 // (LinkOnceODR, WeakODR). 1216 return llvm::GlobalVariable::WeakAnyLinkage; 1217 else if (!getLangOptions().CPlusPlus && !CodeGenOpts.NoCommon && 1218 !D->hasExternalStorage() && !D->getInit() && 1219 !D->getAttr<SectionAttr>() && !D->isThreadSpecified()) { 1220 // Thread local vars aren't considered common linkage. 1221 return llvm::GlobalVariable::CommonLinkage; 1222 } 1223 return llvm::GlobalVariable::ExternalLinkage; 1224} 1225 1226/// ReplaceUsesOfNonProtoTypeWithRealFunction - This function is called when we 1227/// implement a function with no prototype, e.g. "int foo() {}". If there are 1228/// existing call uses of the old function in the module, this adjusts them to 1229/// call the new function directly. 1230/// 1231/// This is not just a cleanup: the always_inline pass requires direct calls to 1232/// functions to be able to inline them. If there is a bitcast in the way, it 1233/// won't inline them. Instcombine normally deletes these calls, but it isn't 1234/// run at -O0. 1235static void ReplaceUsesOfNonProtoTypeWithRealFunction(llvm::GlobalValue *Old, 1236 llvm::Function *NewFn) { 1237 // If we're redefining a global as a function, don't transform it. 1238 llvm::Function *OldFn = dyn_cast<llvm::Function>(Old); 1239 if (OldFn == 0) return; 1240 1241 const llvm::Type *NewRetTy = NewFn->getReturnType(); 1242 llvm::SmallVector<llvm::Value*, 4> ArgList; 1243 1244 for (llvm::Value::use_iterator UI = OldFn->use_begin(), E = OldFn->use_end(); 1245 UI != E; ) { 1246 // TODO: Do invokes ever occur in C code? If so, we should handle them too. 1247 llvm::Value::use_iterator I = UI++; // Increment before the CI is erased. 1248 llvm::CallInst *CI = dyn_cast<llvm::CallInst>(*I); 1249 if (!CI) continue; // FIXME: when we allow Invoke, just do CallSite CS(*I) 1250 llvm::CallSite CS(CI); 1251 if (!CI || !CS.isCallee(I)) continue; 1252 1253 // If the return types don't match exactly, and if the call isn't dead, then 1254 // we can't transform this call. 1255 if (CI->getType() != NewRetTy && !CI->use_empty()) 1256 continue; 1257 1258 // If the function was passed too few arguments, don't transform. If extra 1259 // arguments were passed, we silently drop them. If any of the types 1260 // mismatch, we don't transform. 1261 unsigned ArgNo = 0; 1262 bool DontTransform = false; 1263 for (llvm::Function::arg_iterator AI = NewFn->arg_begin(), 1264 E = NewFn->arg_end(); AI != E; ++AI, ++ArgNo) { 1265 if (CS.arg_size() == ArgNo || 1266 CS.getArgument(ArgNo)->getType() != AI->getType()) { 1267 DontTransform = true; 1268 break; 1269 } 1270 } 1271 if (DontTransform) 1272 continue; 1273 1274 // Okay, we can transform this. Create the new call instruction and copy 1275 // over the required information. 1276 ArgList.append(CS.arg_begin(), CS.arg_begin() + ArgNo); 1277 llvm::CallInst *NewCall = llvm::CallInst::Create(NewFn, ArgList.begin(), 1278 ArgList.end(), "", CI); 1279 ArgList.clear(); 1280 if (!NewCall->getType()->isVoidTy()) 1281 NewCall->takeName(CI); 1282 NewCall->setAttributes(CI->getAttributes()); 1283 NewCall->setCallingConv(CI->getCallingConv()); 1284 1285 // Finally, remove the old call, replacing any uses with the new one. 1286 if (!CI->use_empty()) 1287 CI->replaceAllUsesWith(NewCall); 1288 1289 // Copy debug location attached to CI. 1290 if (!CI->getDebugLoc().isUnknown()) 1291 NewCall->setDebugLoc(CI->getDebugLoc()); 1292 CI->eraseFromParent(); 1293 } 1294} 1295 1296 1297void CodeGenModule::EmitGlobalFunctionDefinition(GlobalDecl GD) { 1298 const FunctionDecl *D = cast<FunctionDecl>(GD.getDecl()); 1299 const llvm::FunctionType *Ty = getTypes().GetFunctionType(GD); 1300 getCXXABI().getMangleContext().mangleInitDiscriminator(); 1301 // Get or create the prototype for the function. 1302 llvm::Constant *Entry = GetAddrOfFunction(GD, Ty); 1303 1304 // Strip off a bitcast if we got one back. 1305 if (llvm::ConstantExpr *CE = dyn_cast<llvm::ConstantExpr>(Entry)) { 1306 assert(CE->getOpcode() == llvm::Instruction::BitCast); 1307 Entry = CE->getOperand(0); 1308 } 1309 1310 1311 if (cast<llvm::GlobalValue>(Entry)->getType()->getElementType() != Ty) { 1312 llvm::GlobalValue *OldFn = cast<llvm::GlobalValue>(Entry); 1313 1314 // If the types mismatch then we have to rewrite the definition. 1315 assert(OldFn->isDeclaration() && 1316 "Shouldn't replace non-declaration"); 1317 1318 // F is the Function* for the one with the wrong type, we must make a new 1319 // Function* and update everything that used F (a declaration) with the new 1320 // Function* (which will be a definition). 1321 // 1322 // This happens if there is a prototype for a function 1323 // (e.g. "int f()") and then a definition of a different type 1324 // (e.g. "int f(int x)"). Move the old function aside so that it 1325 // doesn't interfere with GetAddrOfFunction. 1326 OldFn->setName(llvm::StringRef()); 1327 llvm::Function *NewFn = cast<llvm::Function>(GetAddrOfFunction(GD, Ty)); 1328 1329 // If this is an implementation of a function without a prototype, try to 1330 // replace any existing uses of the function (which may be calls) with uses 1331 // of the new function 1332 if (D->getType()->isFunctionNoProtoType()) { 1333 ReplaceUsesOfNonProtoTypeWithRealFunction(OldFn, NewFn); 1334 OldFn->removeDeadConstantUsers(); 1335 } 1336 1337 // Replace uses of F with the Function we will endow with a body. 1338 if (!Entry->use_empty()) { 1339 llvm::Constant *NewPtrForOldDecl = 1340 llvm::ConstantExpr::getBitCast(NewFn, Entry->getType()); 1341 Entry->replaceAllUsesWith(NewPtrForOldDecl); 1342 } 1343 1344 // Ok, delete the old function now, which is dead. 1345 OldFn->eraseFromParent(); 1346 1347 Entry = NewFn; 1348 } 1349 1350 // We need to set linkage and visibility on the function before 1351 // generating code for it because various parts of IR generation 1352 // want to propagate this information down (e.g. to local static 1353 // declarations). 1354 llvm::Function *Fn = cast<llvm::Function>(Entry); 1355 setFunctionLinkage(D, Fn); 1356 1357 // FIXME: this is redundant with part of SetFunctionDefinitionAttributes 1358 setGlobalVisibility(Fn, D, /*ForDef*/ true); 1359 1360 CodeGenFunction(*this).GenerateCode(D, Fn); 1361 1362 SetFunctionDefinitionAttributes(D, Fn); 1363 SetLLVMFunctionAttributesForDefinition(D, Fn); 1364 1365 if (const ConstructorAttr *CA = D->getAttr<ConstructorAttr>()) 1366 AddGlobalCtor(Fn, CA->getPriority()); 1367 if (const DestructorAttr *DA = D->getAttr<DestructorAttr>()) 1368 AddGlobalDtor(Fn, DA->getPriority()); 1369} 1370 1371void CodeGenModule::EmitAliasDefinition(GlobalDecl GD) { 1372 const ValueDecl *D = cast<ValueDecl>(GD.getDecl()); 1373 const AliasAttr *AA = D->getAttr<AliasAttr>(); 1374 assert(AA && "Not an alias?"); 1375 1376 llvm::StringRef MangledName = getMangledName(GD); 1377 1378 // If there is a definition in the module, then it wins over the alias. 1379 // This is dubious, but allow it to be safe. Just ignore the alias. 1380 llvm::GlobalValue *Entry = GetGlobalValue(MangledName); 1381 if (Entry && !Entry->isDeclaration()) 1382 return; 1383 1384 const llvm::Type *DeclTy = getTypes().ConvertTypeForMem(D->getType()); 1385 1386 // Create a reference to the named value. This ensures that it is emitted 1387 // if a deferred decl. 1388 llvm::Constant *Aliasee; 1389 if (isa<llvm::FunctionType>(DeclTy)) 1390 Aliasee = GetOrCreateLLVMFunction(AA->getAliasee(), DeclTy, GlobalDecl()); 1391 else 1392 Aliasee = GetOrCreateLLVMGlobal(AA->getAliasee(), 1393 llvm::PointerType::getUnqual(DeclTy), 0); 1394 1395 // Create the new alias itself, but don't set a name yet. 1396 llvm::GlobalValue *GA = 1397 new llvm::GlobalAlias(Aliasee->getType(), 1398 llvm::Function::ExternalLinkage, 1399 "", Aliasee, &getModule()); 1400 1401 if (Entry) { 1402 assert(Entry->isDeclaration()); 1403 1404 // If there is a declaration in the module, then we had an extern followed 1405 // by the alias, as in: 1406 // extern int test6(); 1407 // ... 1408 // int test6() __attribute__((alias("test7"))); 1409 // 1410 // Remove it and replace uses of it with the alias. 1411 GA->takeName(Entry); 1412 1413 Entry->replaceAllUsesWith(llvm::ConstantExpr::getBitCast(GA, 1414 Entry->getType())); 1415 Entry->eraseFromParent(); 1416 } else { 1417 GA->setName(MangledName); 1418 } 1419 1420 // Set attributes which are particular to an alias; this is a 1421 // specialization of the attributes which may be set on a global 1422 // variable/function. 1423 if (D->hasAttr<DLLExportAttr>()) { 1424 if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) { 1425 // The dllexport attribute is ignored for undefined symbols. 1426 if (FD->hasBody()) 1427 GA->setLinkage(llvm::Function::DLLExportLinkage); 1428 } else { 1429 GA->setLinkage(llvm::Function::DLLExportLinkage); 1430 } 1431 } else if (D->hasAttr<WeakAttr>() || 1432 D->hasAttr<WeakRefAttr>() || 1433 D->hasAttr<WeakImportAttr>()) { 1434 GA->setLinkage(llvm::Function::WeakAnyLinkage); 1435 } 1436 1437 SetCommonAttributes(D, GA); 1438} 1439 1440/// getBuiltinLibFunction - Given a builtin id for a function like 1441/// "__builtin_fabsf", return a Function* for "fabsf". 1442llvm::Value *CodeGenModule::getBuiltinLibFunction(const FunctionDecl *FD, 1443 unsigned BuiltinID) { 1444 assert((Context.BuiltinInfo.isLibFunction(BuiltinID) || 1445 Context.BuiltinInfo.isPredefinedLibFunction(BuiltinID)) && 1446 "isn't a lib fn"); 1447 1448 // Get the name, skip over the __builtin_ prefix (if necessary). 1449 const char *Name = Context.BuiltinInfo.GetName(BuiltinID); 1450 if (Context.BuiltinInfo.isLibFunction(BuiltinID)) 1451 Name += 10; 1452 1453 const llvm::FunctionType *Ty = 1454 cast<llvm::FunctionType>(getTypes().ConvertType(FD->getType())); 1455 1456 return GetOrCreateLLVMFunction(Name, Ty, GlobalDecl(FD)); 1457} 1458 1459llvm::Function *CodeGenModule::getIntrinsic(unsigned IID,const llvm::Type **Tys, 1460 unsigned NumTys) { 1461 return llvm::Intrinsic::getDeclaration(&getModule(), 1462 (llvm::Intrinsic::ID)IID, Tys, NumTys); 1463} 1464 1465 1466llvm::Function *CodeGenModule::getMemCpyFn(const llvm::Type *DestType, 1467 const llvm::Type *SrcType, 1468 const llvm::Type *SizeType) { 1469 const llvm::Type *ArgTypes[3] = {DestType, SrcType, SizeType }; 1470 return getIntrinsic(llvm::Intrinsic::memcpy, ArgTypes, 3); 1471} 1472 1473llvm::Function *CodeGenModule::getMemMoveFn(const llvm::Type *DestType, 1474 const llvm::Type *SrcType, 1475 const llvm::Type *SizeType) { 1476 const llvm::Type *ArgTypes[3] = {DestType, SrcType, SizeType }; 1477 return getIntrinsic(llvm::Intrinsic::memmove, ArgTypes, 3); 1478} 1479 1480llvm::Function *CodeGenModule::getMemSetFn(const llvm::Type *DestType, 1481 const llvm::Type *SizeType) { 1482 const llvm::Type *ArgTypes[2] = { DestType, SizeType }; 1483 return getIntrinsic(llvm::Intrinsic::memset, ArgTypes, 2); 1484} 1485 1486static llvm::StringMapEntry<llvm::Constant*> & 1487GetConstantCFStringEntry(llvm::StringMap<llvm::Constant*> &Map, 1488 const StringLiteral *Literal, 1489 bool TargetIsLSB, 1490 bool &IsUTF16, 1491 unsigned &StringLength) { 1492 llvm::StringRef String = Literal->getString(); 1493 unsigned NumBytes = String.size(); 1494 1495 // Check for simple case. 1496 if (!Literal->containsNonAsciiOrNull()) { 1497 StringLength = NumBytes; 1498 return Map.GetOrCreateValue(String); 1499 } 1500 1501 // Otherwise, convert the UTF8 literals into a byte string. 1502 llvm::SmallVector<UTF16, 128> ToBuf(NumBytes); 1503 const UTF8 *FromPtr = (UTF8 *)String.data(); 1504 UTF16 *ToPtr = &ToBuf[0]; 1505 1506 (void)ConvertUTF8toUTF16(&FromPtr, FromPtr + NumBytes, 1507 &ToPtr, ToPtr + NumBytes, 1508 strictConversion); 1509 1510 // ConvertUTF8toUTF16 returns the length in ToPtr. 1511 StringLength = ToPtr - &ToBuf[0]; 1512 1513 // Render the UTF-16 string into a byte array and convert to the target byte 1514 // order. 1515 // 1516 // FIXME: This isn't something we should need to do here. 1517 llvm::SmallString<128> AsBytes; 1518 AsBytes.reserve(StringLength * 2); 1519 for (unsigned i = 0; i != StringLength; ++i) { 1520 unsigned short Val = ToBuf[i]; 1521 if (TargetIsLSB) { 1522 AsBytes.push_back(Val & 0xFF); 1523 AsBytes.push_back(Val >> 8); 1524 } else { 1525 AsBytes.push_back(Val >> 8); 1526 AsBytes.push_back(Val & 0xFF); 1527 } 1528 } 1529 // Append one extra null character, the second is automatically added by our 1530 // caller. 1531 AsBytes.push_back(0); 1532 1533 IsUTF16 = true; 1534 return Map.GetOrCreateValue(llvm::StringRef(AsBytes.data(), AsBytes.size())); 1535} 1536 1537llvm::Constant * 1538CodeGenModule::GetAddrOfConstantCFString(const StringLiteral *Literal) { 1539 unsigned StringLength = 0; 1540 bool isUTF16 = false; 1541 llvm::StringMapEntry<llvm::Constant*> &Entry = 1542 GetConstantCFStringEntry(CFConstantStringMap, Literal, 1543 getTargetData().isLittleEndian(), 1544 isUTF16, StringLength); 1545 1546 if (llvm::Constant *C = Entry.getValue()) 1547 return C; 1548 1549 llvm::Constant *Zero = 1550 llvm::Constant::getNullValue(llvm::Type::getInt32Ty(VMContext)); 1551 llvm::Constant *Zeros[] = { Zero, Zero }; 1552 1553 // If we don't already have it, get __CFConstantStringClassReference. 1554 if (!CFConstantStringClassRef) { 1555 const llvm::Type *Ty = getTypes().ConvertType(getContext().IntTy); 1556 Ty = llvm::ArrayType::get(Ty, 0); 1557 llvm::Constant *GV = CreateRuntimeVariable(Ty, 1558 "__CFConstantStringClassReference"); 1559 // Decay array -> ptr 1560 CFConstantStringClassRef = 1561 llvm::ConstantExpr::getGetElementPtr(GV, Zeros, 2); 1562 } 1563 1564 QualType CFTy = getContext().getCFConstantStringType(); 1565 1566 const llvm::StructType *STy = 1567 cast<llvm::StructType>(getTypes().ConvertType(CFTy)); 1568 1569 std::vector<llvm::Constant*> Fields(4); 1570 1571 // Class pointer. 1572 Fields[0] = CFConstantStringClassRef; 1573 1574 // Flags. 1575 const llvm::Type *Ty = getTypes().ConvertType(getContext().UnsignedIntTy); 1576 Fields[1] = isUTF16 ? llvm::ConstantInt::get(Ty, 0x07d0) : 1577 llvm::ConstantInt::get(Ty, 0x07C8); 1578 1579 // String pointer. 1580 llvm::Constant *C = llvm::ConstantArray::get(VMContext, Entry.getKey().str()); 1581 1582 llvm::GlobalValue::LinkageTypes Linkage; 1583 bool isConstant; 1584 if (isUTF16) { 1585 // FIXME: why do utf strings get "_" labels instead of "L" labels? 1586 Linkage = llvm::GlobalValue::InternalLinkage; 1587 // Note: -fwritable-strings doesn't make unicode CFStrings writable, but 1588 // does make plain ascii ones writable. 1589 isConstant = true; 1590 } else { 1591 Linkage = llvm::GlobalValue::PrivateLinkage; 1592 isConstant = !Features.WritableStrings; 1593 } 1594 1595 llvm::GlobalVariable *GV = 1596 new llvm::GlobalVariable(getModule(), C->getType(), isConstant, Linkage, C, 1597 ".str"); 1598 if (isUTF16) { 1599 CharUnits Align = getContext().getTypeAlignInChars(getContext().ShortTy); 1600 GV->setAlignment(Align.getQuantity()); 1601 } 1602 Fields[2] = llvm::ConstantExpr::getGetElementPtr(GV, Zeros, 2); 1603 1604 // String length. 1605 Ty = getTypes().ConvertType(getContext().LongTy); 1606 Fields[3] = llvm::ConstantInt::get(Ty, StringLength); 1607 1608 // The struct. 1609 C = llvm::ConstantStruct::get(STy, Fields); 1610 GV = new llvm::GlobalVariable(getModule(), C->getType(), true, 1611 llvm::GlobalVariable::PrivateLinkage, C, 1612 "_unnamed_cfstring_"); 1613 if (const char *Sect = getContext().Target.getCFStringSection()) 1614 GV->setSection(Sect); 1615 Entry.setValue(GV); 1616 1617 return GV; 1618} 1619 1620llvm::Constant * 1621CodeGenModule::GetAddrOfConstantString(const StringLiteral *Literal) { 1622 unsigned StringLength = 0; 1623 bool isUTF16 = false; 1624 llvm::StringMapEntry<llvm::Constant*> &Entry = 1625 GetConstantCFStringEntry(CFConstantStringMap, Literal, 1626 getTargetData().isLittleEndian(), 1627 isUTF16, StringLength); 1628 1629 if (llvm::Constant *C = Entry.getValue()) 1630 return C; 1631 1632 llvm::Constant *Zero = 1633 llvm::Constant::getNullValue(llvm::Type::getInt32Ty(VMContext)); 1634 llvm::Constant *Zeros[] = { Zero, Zero }; 1635 1636 // If we don't already have it, get _NSConstantStringClassReference. 1637 if (!ConstantStringClassRef) { 1638 std::string StringClass(getLangOptions().ObjCConstantStringClass); 1639 const llvm::Type *Ty = getTypes().ConvertType(getContext().IntTy); 1640 Ty = llvm::ArrayType::get(Ty, 0); 1641 llvm::Constant *GV; 1642 if (StringClass.empty()) 1643 GV = CreateRuntimeVariable(Ty, 1644 Features.ObjCNonFragileABI ? 1645 "OBJC_CLASS_$_NSConstantString" : 1646 "_NSConstantStringClassReference"); 1647 else { 1648 std::string str; 1649 if (Features.ObjCNonFragileABI) 1650 str = "OBJC_CLASS_$_" + StringClass; 1651 else 1652 str = "_" + StringClass + "ClassReference"; 1653 GV = CreateRuntimeVariable(Ty, str); 1654 } 1655 // Decay array -> ptr 1656 ConstantStringClassRef = 1657 llvm::ConstantExpr::getGetElementPtr(GV, Zeros, 2); 1658 } 1659 1660 QualType NSTy = getContext().getNSConstantStringType(); 1661 1662 const llvm::StructType *STy = 1663 cast<llvm::StructType>(getTypes().ConvertType(NSTy)); 1664 1665 std::vector<llvm::Constant*> Fields(3); 1666 1667 // Class pointer. 1668 Fields[0] = ConstantStringClassRef; 1669 1670 // String pointer. 1671 llvm::Constant *C = llvm::ConstantArray::get(VMContext, Entry.getKey().str()); 1672 1673 llvm::GlobalValue::LinkageTypes Linkage; 1674 bool isConstant; 1675 if (isUTF16) { 1676 // FIXME: why do utf strings get "_" labels instead of "L" labels? 1677 Linkage = llvm::GlobalValue::InternalLinkage; 1678 // Note: -fwritable-strings doesn't make unicode NSStrings writable, but 1679 // does make plain ascii ones writable. 1680 isConstant = true; 1681 } else { 1682 Linkage = llvm::GlobalValue::PrivateLinkage; 1683 isConstant = !Features.WritableStrings; 1684 } 1685 1686 llvm::GlobalVariable *GV = 1687 new llvm::GlobalVariable(getModule(), C->getType(), isConstant, Linkage, C, 1688 ".str"); 1689 if (isUTF16) { 1690 CharUnits Align = getContext().getTypeAlignInChars(getContext().ShortTy); 1691 GV->setAlignment(Align.getQuantity()); 1692 } 1693 Fields[1] = llvm::ConstantExpr::getGetElementPtr(GV, Zeros, 2); 1694 1695 // String length. 1696 const llvm::Type *Ty = getTypes().ConvertType(getContext().UnsignedIntTy); 1697 Fields[2] = llvm::ConstantInt::get(Ty, StringLength); 1698 1699 // The struct. 1700 C = llvm::ConstantStruct::get(STy, Fields); 1701 GV = new llvm::GlobalVariable(getModule(), C->getType(), true, 1702 llvm::GlobalVariable::PrivateLinkage, C, 1703 "_unnamed_nsstring_"); 1704 // FIXME. Fix section. 1705 if (const char *Sect = 1706 Features.ObjCNonFragileABI 1707 ? getContext().Target.getNSStringNonFragileABISection() 1708 : getContext().Target.getNSStringSection()) 1709 GV->setSection(Sect); 1710 Entry.setValue(GV); 1711 1712 return GV; 1713} 1714 1715/// GetStringForStringLiteral - Return the appropriate bytes for a 1716/// string literal, properly padded to match the literal type. 1717std::string CodeGenModule::GetStringForStringLiteral(const StringLiteral *E) { 1718 const ConstantArrayType *CAT = 1719 getContext().getAsConstantArrayType(E->getType()); 1720 assert(CAT && "String isn't pointer or array!"); 1721 1722 // Resize the string to the right size. 1723 uint64_t RealLen = CAT->getSize().getZExtValue(); 1724 1725 if (E->isWide()) 1726 RealLen *= getContext().Target.getWCharWidth()/8; 1727 1728 std::string Str = E->getString().str(); 1729 Str.resize(RealLen, '\0'); 1730 1731 return Str; 1732} 1733 1734/// GetAddrOfConstantStringFromLiteral - Return a pointer to a 1735/// constant array for the given string literal. 1736llvm::Constant * 1737CodeGenModule::GetAddrOfConstantStringFromLiteral(const StringLiteral *S) { 1738 // FIXME: This can be more efficient. 1739 // FIXME: We shouldn't need to bitcast the constant in the wide string case. 1740 llvm::Constant *C = GetAddrOfConstantString(GetStringForStringLiteral(S)); 1741 if (S->isWide()) { 1742 llvm::Type *DestTy = 1743 llvm::PointerType::getUnqual(getTypes().ConvertType(S->getType())); 1744 C = llvm::ConstantExpr::getBitCast(C, DestTy); 1745 } 1746 return C; 1747} 1748 1749/// GetAddrOfConstantStringFromObjCEncode - Return a pointer to a constant 1750/// array for the given ObjCEncodeExpr node. 1751llvm::Constant * 1752CodeGenModule::GetAddrOfConstantStringFromObjCEncode(const ObjCEncodeExpr *E) { 1753 std::string Str; 1754 getContext().getObjCEncodingForType(E->getEncodedType(), Str); 1755 1756 return GetAddrOfConstantCString(Str); 1757} 1758 1759 1760/// GenerateWritableString -- Creates storage for a string literal. 1761static llvm::Constant *GenerateStringLiteral(const std::string &str, 1762 bool constant, 1763 CodeGenModule &CGM, 1764 const char *GlobalName) { 1765 // Create Constant for this string literal. Don't add a '\0'. 1766 llvm::Constant *C = 1767 llvm::ConstantArray::get(CGM.getLLVMContext(), str, false); 1768 1769 // Create a global variable for this string 1770 return new llvm::GlobalVariable(CGM.getModule(), C->getType(), constant, 1771 llvm::GlobalValue::PrivateLinkage, 1772 C, GlobalName); 1773} 1774 1775/// GetAddrOfConstantString - Returns a pointer to a character array 1776/// containing the literal. This contents are exactly that of the 1777/// given string, i.e. it will not be null terminated automatically; 1778/// see GetAddrOfConstantCString. Note that whether the result is 1779/// actually a pointer to an LLVM constant depends on 1780/// Feature.WriteableStrings. 1781/// 1782/// The result has pointer to array type. 1783llvm::Constant *CodeGenModule::GetAddrOfConstantString(const std::string &str, 1784 const char *GlobalName) { 1785 bool IsConstant = !Features.WritableStrings; 1786 1787 // Get the default prefix if a name wasn't specified. 1788 if (!GlobalName) 1789 GlobalName = ".str"; 1790 1791 // Don't share any string literals if strings aren't constant. 1792 if (!IsConstant) 1793 return GenerateStringLiteral(str, false, *this, GlobalName); 1794 1795 llvm::StringMapEntry<llvm::Constant *> &Entry = 1796 ConstantStringMap.GetOrCreateValue(&str[0], &str[str.length()]); 1797 1798 if (Entry.getValue()) 1799 return Entry.getValue(); 1800 1801 // Create a global variable for this. 1802 llvm::Constant *C = GenerateStringLiteral(str, true, *this, GlobalName); 1803 Entry.setValue(C); 1804 return C; 1805} 1806 1807/// GetAddrOfConstantCString - Returns a pointer to a character 1808/// array containing the literal and a terminating '\-' 1809/// character. The result has pointer to array type. 1810llvm::Constant *CodeGenModule::GetAddrOfConstantCString(const std::string &str, 1811 const char *GlobalName){ 1812 return GetAddrOfConstantString(str + '\0', GlobalName); 1813} 1814 1815/// EmitObjCPropertyImplementations - Emit information for synthesized 1816/// properties for an implementation. 1817void CodeGenModule::EmitObjCPropertyImplementations(const 1818 ObjCImplementationDecl *D) { 1819 for (ObjCImplementationDecl::propimpl_iterator 1820 i = D->propimpl_begin(), e = D->propimpl_end(); i != e; ++i) { 1821 ObjCPropertyImplDecl *PID = *i; 1822 1823 // Dynamic is just for type-checking. 1824 if (PID->getPropertyImplementation() == ObjCPropertyImplDecl::Synthesize) { 1825 ObjCPropertyDecl *PD = PID->getPropertyDecl(); 1826 1827 // Determine which methods need to be implemented, some may have 1828 // been overridden. Note that ::isSynthesized is not the method 1829 // we want, that just indicates if the decl came from a 1830 // property. What we want to know is if the method is defined in 1831 // this implementation. 1832 if (!D->getInstanceMethod(PD->getGetterName())) 1833 CodeGenFunction(*this).GenerateObjCGetter( 1834 const_cast<ObjCImplementationDecl *>(D), PID); 1835 if (!PD->isReadOnly() && 1836 !D->getInstanceMethod(PD->getSetterName())) 1837 CodeGenFunction(*this).GenerateObjCSetter( 1838 const_cast<ObjCImplementationDecl *>(D), PID); 1839 } 1840 } 1841} 1842 1843/// EmitObjCIvarInitializations - Emit information for ivar initialization 1844/// for an implementation. 1845void CodeGenModule::EmitObjCIvarInitializations(ObjCImplementationDecl *D) { 1846 if (!Features.NeXTRuntime || D->getNumIvarInitializers() == 0) 1847 return; 1848 DeclContext* DC = const_cast<DeclContext*>(dyn_cast<DeclContext>(D)); 1849 assert(DC && "EmitObjCIvarInitializations - null DeclContext"); 1850 IdentifierInfo *II = &getContext().Idents.get(".cxx_destruct"); 1851 Selector cxxSelector = getContext().Selectors.getSelector(0, &II); 1852 ObjCMethodDecl *DTORMethod = ObjCMethodDecl::Create(getContext(), 1853 D->getLocation(), 1854 D->getLocation(), cxxSelector, 1855 getContext().VoidTy, 0, 1856 DC, true, false, true, false, 1857 ObjCMethodDecl::Required); 1858 D->addInstanceMethod(DTORMethod); 1859 CodeGenFunction(*this).GenerateObjCCtorDtorMethod(D, DTORMethod, false); 1860 1861 II = &getContext().Idents.get(".cxx_construct"); 1862 cxxSelector = getContext().Selectors.getSelector(0, &II); 1863 // The constructor returns 'self'. 1864 ObjCMethodDecl *CTORMethod = ObjCMethodDecl::Create(getContext(), 1865 D->getLocation(), 1866 D->getLocation(), cxxSelector, 1867 getContext().getObjCIdType(), 0, 1868 DC, true, false, true, false, 1869 ObjCMethodDecl::Required); 1870 D->addInstanceMethod(CTORMethod); 1871 CodeGenFunction(*this).GenerateObjCCtorDtorMethod(D, CTORMethod, true); 1872 1873 1874} 1875 1876/// EmitNamespace - Emit all declarations in a namespace. 1877void CodeGenModule::EmitNamespace(const NamespaceDecl *ND) { 1878 for (RecordDecl::decl_iterator I = ND->decls_begin(), E = ND->decls_end(); 1879 I != E; ++I) 1880 EmitTopLevelDecl(*I); 1881} 1882 1883// EmitLinkageSpec - Emit all declarations in a linkage spec. 1884void CodeGenModule::EmitLinkageSpec(const LinkageSpecDecl *LSD) { 1885 if (LSD->getLanguage() != LinkageSpecDecl::lang_c && 1886 LSD->getLanguage() != LinkageSpecDecl::lang_cxx) { 1887 ErrorUnsupported(LSD, "linkage spec"); 1888 return; 1889 } 1890 1891 for (RecordDecl::decl_iterator I = LSD->decls_begin(), E = LSD->decls_end(); 1892 I != E; ++I) 1893 EmitTopLevelDecl(*I); 1894} 1895 1896/// EmitTopLevelDecl - Emit code for a single top level declaration. 1897void CodeGenModule::EmitTopLevelDecl(Decl *D) { 1898 // If an error has occurred, stop code generation, but continue 1899 // parsing and semantic analysis (to ensure all warnings and errors 1900 // are emitted). 1901 if (Diags.hasErrorOccurred()) 1902 return; 1903 1904 // Ignore dependent declarations. 1905 if (D->getDeclContext() && D->getDeclContext()->isDependentContext()) 1906 return; 1907 1908 switch (D->getKind()) { 1909 case Decl::CXXConversion: 1910 case Decl::CXXMethod: 1911 case Decl::Function: 1912 // Skip function templates 1913 if (cast<FunctionDecl>(D)->getDescribedFunctionTemplate()) 1914 return; 1915 1916 EmitGlobal(cast<FunctionDecl>(D)); 1917 break; 1918 1919 case Decl::Var: 1920 EmitGlobal(cast<VarDecl>(D)); 1921 break; 1922 1923 // C++ Decls 1924 case Decl::Namespace: 1925 EmitNamespace(cast<NamespaceDecl>(D)); 1926 break; 1927 // No code generation needed. 1928 case Decl::UsingShadow: 1929 case Decl::Using: 1930 case Decl::UsingDirective: 1931 case Decl::ClassTemplate: 1932 case Decl::FunctionTemplate: 1933 case Decl::NamespaceAlias: 1934 break; 1935 case Decl::CXXConstructor: 1936 // Skip function templates 1937 if (cast<FunctionDecl>(D)->getDescribedFunctionTemplate()) 1938 return; 1939 1940 EmitCXXConstructors(cast<CXXConstructorDecl>(D)); 1941 break; 1942 case Decl::CXXDestructor: 1943 EmitCXXDestructors(cast<CXXDestructorDecl>(D)); 1944 break; 1945 1946 case Decl::StaticAssert: 1947 // Nothing to do. 1948 break; 1949 1950 // Objective-C Decls 1951 1952 // Forward declarations, no (immediate) code generation. 1953 case Decl::ObjCClass: 1954 case Decl::ObjCForwardProtocol: 1955 case Decl::ObjCInterface: 1956 break; 1957 1958 case Decl::ObjCCategory: { 1959 ObjCCategoryDecl *CD = cast<ObjCCategoryDecl>(D); 1960 if (CD->IsClassExtension() && CD->hasSynthBitfield()) 1961 Context.ResetObjCLayout(CD->getClassInterface()); 1962 break; 1963 } 1964 1965 1966 case Decl::ObjCProtocol: 1967 Runtime->GenerateProtocol(cast<ObjCProtocolDecl>(D)); 1968 break; 1969 1970 case Decl::ObjCCategoryImpl: 1971 // Categories have properties but don't support synthesize so we 1972 // can ignore them here. 1973 Runtime->GenerateCategory(cast<ObjCCategoryImplDecl>(D)); 1974 break; 1975 1976 case Decl::ObjCImplementation: { 1977 ObjCImplementationDecl *OMD = cast<ObjCImplementationDecl>(D); 1978 if (Features.ObjCNonFragileABI2 && OMD->hasSynthBitfield()) 1979 Context.ResetObjCLayout(OMD->getClassInterface()); 1980 EmitObjCPropertyImplementations(OMD); 1981 EmitObjCIvarInitializations(OMD); 1982 Runtime->GenerateClass(OMD); 1983 break; 1984 } 1985 case Decl::ObjCMethod: { 1986 ObjCMethodDecl *OMD = cast<ObjCMethodDecl>(D); 1987 // If this is not a prototype, emit the body. 1988 if (OMD->getBody()) 1989 CodeGenFunction(*this).GenerateObjCMethod(OMD); 1990 break; 1991 } 1992 case Decl::ObjCCompatibleAlias: 1993 // compatibility-alias is a directive and has no code gen. 1994 break; 1995 1996 case Decl::LinkageSpec: 1997 EmitLinkageSpec(cast<LinkageSpecDecl>(D)); 1998 break; 1999 2000 case Decl::FileScopeAsm: { 2001 FileScopeAsmDecl *AD = cast<FileScopeAsmDecl>(D); 2002 llvm::StringRef AsmString = AD->getAsmString()->getString(); 2003 2004 const std::string &S = getModule().getModuleInlineAsm(); 2005 if (S.empty()) 2006 getModule().setModuleInlineAsm(AsmString); 2007 else 2008 getModule().setModuleInlineAsm(S + '\n' + AsmString.str()); 2009 break; 2010 } 2011 2012 default: 2013 // Make sure we handled everything we should, every other kind is a 2014 // non-top-level decl. FIXME: Would be nice to have an isTopLevelDeclKind 2015 // function. Need to recode Decl::Kind to do that easily. 2016 assert(isa<TypeDecl>(D) && "Unsupported decl kind"); 2017 } 2018} 2019 2020/// Turns the given pointer into a constant. 2021static llvm::Constant *GetPointerConstant(llvm::LLVMContext &Context, 2022 const void *Ptr) { 2023 uintptr_t PtrInt = reinterpret_cast<uintptr_t>(Ptr); 2024 const llvm::Type *i64 = llvm::Type::getInt64Ty(Context); 2025 return llvm::ConstantInt::get(i64, PtrInt); 2026} 2027 2028static void EmitGlobalDeclMetadata(CodeGenModule &CGM, 2029 llvm::NamedMDNode *&GlobalMetadata, 2030 GlobalDecl D, 2031 llvm::GlobalValue *Addr) { 2032 if (!GlobalMetadata) 2033 GlobalMetadata = 2034 CGM.getModule().getOrInsertNamedMetadata("clang.global.decl.ptrs"); 2035 2036 // TODO: should we report variant information for ctors/dtors? 2037 llvm::Value *Ops[] = { 2038 Addr, 2039 GetPointerConstant(CGM.getLLVMContext(), D.getDecl()) 2040 }; 2041 GlobalMetadata->addOperand(llvm::MDNode::get(CGM.getLLVMContext(), Ops, 2)); 2042} 2043 2044/// Emits metadata nodes associating all the global values in the 2045/// current module with the Decls they came from. This is useful for 2046/// projects using IR gen as a subroutine. 2047/// 2048/// Since there's currently no way to associate an MDNode directly 2049/// with an llvm::GlobalValue, we create a global named metadata 2050/// with the name 'clang.global.decl.ptrs'. 2051void CodeGenModule::EmitDeclMetadata() { 2052 llvm::NamedMDNode *GlobalMetadata = 0; 2053 2054 // StaticLocalDeclMap 2055 for (llvm::DenseMap<GlobalDecl,llvm::StringRef>::iterator 2056 I = MangledDeclNames.begin(), E = MangledDeclNames.end(); 2057 I != E; ++I) { 2058 llvm::GlobalValue *Addr = getModule().getNamedValue(I->second); 2059 EmitGlobalDeclMetadata(*this, GlobalMetadata, I->first, Addr); 2060 } 2061} 2062 2063/// Emits metadata nodes for all the local variables in the current 2064/// function. 2065void CodeGenFunction::EmitDeclMetadata() { 2066 if (LocalDeclMap.empty()) return; 2067 2068 llvm::LLVMContext &Context = getLLVMContext(); 2069 2070 // Find the unique metadata ID for this name. 2071 unsigned DeclPtrKind = Context.getMDKindID("clang.decl.ptr"); 2072 2073 llvm::NamedMDNode *GlobalMetadata = 0; 2074 2075 for (llvm::DenseMap<const Decl*, llvm::Value*>::iterator 2076 I = LocalDeclMap.begin(), E = LocalDeclMap.end(); I != E; ++I) { 2077 const Decl *D = I->first; 2078 llvm::Value *Addr = I->second; 2079 2080 if (llvm::AllocaInst *Alloca = dyn_cast<llvm::AllocaInst>(Addr)) { 2081 llvm::Value *DAddr = GetPointerConstant(getLLVMContext(), D); 2082 Alloca->setMetadata(DeclPtrKind, llvm::MDNode::get(Context, &DAddr, 1)); 2083 } else if (llvm::GlobalValue *GV = dyn_cast<llvm::GlobalValue>(Addr)) { 2084 GlobalDecl GD = GlobalDecl(cast<VarDecl>(D)); 2085 EmitGlobalDeclMetadata(CGM, GlobalMetadata, GD, GV); 2086 } 2087 } 2088} 2089 2090///@name Custom Runtime Function Interfaces 2091///@{ 2092// 2093// FIXME: These can be eliminated once we can have clients just get the required 2094// AST nodes from the builtin tables. 2095 2096llvm::Constant *CodeGenModule::getBlockObjectDispose() { 2097 if (BlockObjectDispose) 2098 return BlockObjectDispose; 2099 2100 // If we saw an explicit decl, use that. 2101 if (BlockObjectDisposeDecl) { 2102 return BlockObjectDispose = GetAddrOfFunction( 2103 BlockObjectDisposeDecl, 2104 getTypes().GetFunctionType(BlockObjectDisposeDecl)); 2105 } 2106 2107 // Otherwise construct the function by hand. 2108 const llvm::FunctionType *FTy; 2109 std::vector<const llvm::Type*> ArgTys; 2110 const llvm::Type *ResultType = llvm::Type::getVoidTy(VMContext); 2111 ArgTys.push_back(PtrToInt8Ty); 2112 ArgTys.push_back(llvm::Type::getInt32Ty(VMContext)); 2113 FTy = llvm::FunctionType::get(ResultType, ArgTys, false); 2114 return BlockObjectDispose = 2115 CreateRuntimeFunction(FTy, "_Block_object_dispose"); 2116} 2117 2118llvm::Constant *CodeGenModule::getBlockObjectAssign() { 2119 if (BlockObjectAssign) 2120 return BlockObjectAssign; 2121 2122 // If we saw an explicit decl, use that. 2123 if (BlockObjectAssignDecl) { 2124 return BlockObjectAssign = GetAddrOfFunction( 2125 BlockObjectAssignDecl, 2126 getTypes().GetFunctionType(BlockObjectAssignDecl)); 2127 } 2128 2129 // Otherwise construct the function by hand. 2130 const llvm::FunctionType *FTy; 2131 std::vector<const llvm::Type*> ArgTys; 2132 const llvm::Type *ResultType = llvm::Type::getVoidTy(VMContext); 2133 ArgTys.push_back(PtrToInt8Ty); 2134 ArgTys.push_back(PtrToInt8Ty); 2135 ArgTys.push_back(llvm::Type::getInt32Ty(VMContext)); 2136 FTy = llvm::FunctionType::get(ResultType, ArgTys, false); 2137 return BlockObjectAssign = 2138 CreateRuntimeFunction(FTy, "_Block_object_assign"); 2139} 2140 2141llvm::Constant *CodeGenModule::getNSConcreteGlobalBlock() { 2142 if (NSConcreteGlobalBlock) 2143 return NSConcreteGlobalBlock; 2144 2145 // If we saw an explicit decl, use that. 2146 if (NSConcreteGlobalBlockDecl) { 2147 return NSConcreteGlobalBlock = GetAddrOfGlobalVar( 2148 NSConcreteGlobalBlockDecl, 2149 getTypes().ConvertType(NSConcreteGlobalBlockDecl->getType())); 2150 } 2151 2152 // Otherwise construct the variable by hand. 2153 return NSConcreteGlobalBlock = CreateRuntimeVariable( 2154 PtrToInt8Ty, "_NSConcreteGlobalBlock"); 2155} 2156 2157llvm::Constant *CodeGenModule::getNSConcreteStackBlock() { 2158 if (NSConcreteStackBlock) 2159 return NSConcreteStackBlock; 2160 2161 // If we saw an explicit decl, use that. 2162 if (NSConcreteStackBlockDecl) { 2163 return NSConcreteStackBlock = GetAddrOfGlobalVar( 2164 NSConcreteStackBlockDecl, 2165 getTypes().ConvertType(NSConcreteStackBlockDecl->getType())); 2166 } 2167 2168 // Otherwise construct the variable by hand. 2169 return NSConcreteStackBlock = CreateRuntimeVariable( 2170 PtrToInt8Ty, "_NSConcreteStackBlock"); 2171} 2172 2173///@} 2174