CodeGenModule.cpp revision c532b502858032f377056dc8cba2fe43cba8702b
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 "TargetInfo.h" 22#include "clang/Frontend/CodeGenOptions.h" 23#include "clang/AST/ASTContext.h" 24#include "clang/AST/CharUnits.h" 25#include "clang/AST/DeclObjC.h" 26#include "clang/AST/DeclCXX.h" 27#include "clang/AST/DeclTemplate.h" 28#include "clang/AST/Mangle.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 GV->setUnnamedAddr(true); 255} 256 257llvm::StringRef CodeGenModule::getMangledName(GlobalDecl GD) { 258 const NamedDecl *ND = cast<NamedDecl>(GD.getDecl()); 259 260 llvm::StringRef &Str = MangledDeclNames[GD.getCanonicalDecl()]; 261 if (!Str.empty()) 262 return Str; 263 264 if (!getCXXABI().getMangleContext().shouldMangleDeclName(ND)) { 265 IdentifierInfo *II = ND->getIdentifier(); 266 assert(II && "Attempt to mangle unnamed decl."); 267 268 Str = II->getName(); 269 return Str; 270 } 271 272 llvm::SmallString<256> Buffer; 273 if (const CXXConstructorDecl *D = dyn_cast<CXXConstructorDecl>(ND)) 274 getCXXABI().getMangleContext().mangleCXXCtor(D, GD.getCtorType(), Buffer); 275 else if (const CXXDestructorDecl *D = dyn_cast<CXXDestructorDecl>(ND)) 276 getCXXABI().getMangleContext().mangleCXXDtor(D, GD.getDtorType(), Buffer); 277 else if (const BlockDecl *BD = dyn_cast<BlockDecl>(ND)) 278 getCXXABI().getMangleContext().mangleBlock(BD, Buffer); 279 else 280 getCXXABI().getMangleContext().mangleName(ND, Buffer); 281 282 // Allocate space for the mangled name. 283 size_t Length = Buffer.size(); 284 char *Name = MangledNamesAllocator.Allocate<char>(Length); 285 std::copy(Buffer.begin(), Buffer.end(), Name); 286 287 Str = llvm::StringRef(Name, Length); 288 289 return Str; 290} 291 292void CodeGenModule::getBlockMangledName(GlobalDecl GD, MangleBuffer &Buffer, 293 const BlockDecl *BD) { 294 MangleContext &MangleCtx = getCXXABI().getMangleContext(); 295 const Decl *D = GD.getDecl(); 296 if (D == 0) 297 MangleCtx.mangleGlobalBlock(BD, Buffer.getBuffer()); 298 else if (const CXXConstructorDecl *CD = dyn_cast<CXXConstructorDecl>(D)) 299 MangleCtx.mangleCtorBlock(CD, GD.getCtorType(), BD, Buffer.getBuffer()); 300 else if (const CXXDestructorDecl *DD = dyn_cast<CXXDestructorDecl>(D)) 301 MangleCtx.mangleDtorBlock(DD, GD.getDtorType(), BD, Buffer.getBuffer()); 302 else 303 MangleCtx.mangleBlock(cast<DeclContext>(D), BD, Buffer.getBuffer()); 304} 305 306llvm::GlobalValue *CodeGenModule::GetGlobalValue(llvm::StringRef Name) { 307 return getModule().getNamedValue(Name); 308} 309 310/// AddGlobalCtor - Add a function to the list that will be called before 311/// main() runs. 312void CodeGenModule::AddGlobalCtor(llvm::Function * Ctor, int Priority) { 313 // FIXME: Type coercion of void()* types. 314 GlobalCtors.push_back(std::make_pair(Ctor, Priority)); 315} 316 317/// AddGlobalDtor - Add a function to the list that will be called 318/// when the module is unloaded. 319void CodeGenModule::AddGlobalDtor(llvm::Function * Dtor, int Priority) { 320 // FIXME: Type coercion of void()* types. 321 GlobalDtors.push_back(std::make_pair(Dtor, Priority)); 322} 323 324void CodeGenModule::EmitCtorList(const CtorList &Fns, const char *GlobalName) { 325 // Ctor function type is void()*. 326 llvm::FunctionType* CtorFTy = 327 llvm::FunctionType::get(llvm::Type::getVoidTy(VMContext), 328 std::vector<const llvm::Type*>(), 329 false); 330 llvm::Type *CtorPFTy = llvm::PointerType::getUnqual(CtorFTy); 331 332 // Get the type of a ctor entry, { i32, void ()* }. 333 llvm::StructType* CtorStructTy = 334 llvm::StructType::get(VMContext, llvm::Type::getInt32Ty(VMContext), 335 llvm::PointerType::getUnqual(CtorFTy), NULL); 336 337 // Construct the constructor and destructor arrays. 338 std::vector<llvm::Constant*> Ctors; 339 for (CtorList::const_iterator I = Fns.begin(), E = Fns.end(); I != E; ++I) { 340 std::vector<llvm::Constant*> S; 341 S.push_back(llvm::ConstantInt::get(llvm::Type::getInt32Ty(VMContext), 342 I->second, false)); 343 S.push_back(llvm::ConstantExpr::getBitCast(I->first, CtorPFTy)); 344 Ctors.push_back(llvm::ConstantStruct::get(CtorStructTy, S)); 345 } 346 347 if (!Ctors.empty()) { 348 llvm::ArrayType *AT = llvm::ArrayType::get(CtorStructTy, Ctors.size()); 349 new llvm::GlobalVariable(TheModule, AT, false, 350 llvm::GlobalValue::AppendingLinkage, 351 llvm::ConstantArray::get(AT, Ctors), 352 GlobalName); 353 } 354} 355 356void CodeGenModule::EmitAnnotations() { 357 if (Annotations.empty()) 358 return; 359 360 // Create a new global variable for the ConstantStruct in the Module. 361 llvm::Constant *Array = 362 llvm::ConstantArray::get(llvm::ArrayType::get(Annotations[0]->getType(), 363 Annotations.size()), 364 Annotations); 365 llvm::GlobalValue *gv = 366 new llvm::GlobalVariable(TheModule, Array->getType(), false, 367 llvm::GlobalValue::AppendingLinkage, Array, 368 "llvm.global.annotations"); 369 gv->setSection("llvm.metadata"); 370} 371 372llvm::GlobalValue::LinkageTypes 373CodeGenModule::getFunctionLinkage(const FunctionDecl *D) { 374 GVALinkage Linkage = getContext().GetGVALinkageForFunction(D); 375 376 if (Linkage == GVA_Internal) 377 return llvm::Function::InternalLinkage; 378 379 if (D->hasAttr<DLLExportAttr>()) 380 return llvm::Function::DLLExportLinkage; 381 382 if (D->hasAttr<WeakAttr>()) 383 return llvm::Function::WeakAnyLinkage; 384 385 // In C99 mode, 'inline' functions are guaranteed to have a strong 386 // definition somewhere else, so we can use available_externally linkage. 387 if (Linkage == GVA_C99Inline) 388 return llvm::Function::AvailableExternallyLinkage; 389 390 // In C++, the compiler has to emit a definition in every translation unit 391 // that references the function. We should use linkonce_odr because 392 // a) if all references in this translation unit are optimized away, we 393 // don't need to codegen it. b) if the function persists, it needs to be 394 // merged with other definitions. c) C++ has the ODR, so we know the 395 // definition is dependable. 396 if (Linkage == GVA_CXXInline || Linkage == GVA_TemplateInstantiation) 397 return llvm::Function::LinkOnceODRLinkage; 398 399 // An explicit instantiation of a template has weak linkage, since 400 // explicit instantiations can occur in multiple translation units 401 // and must all be equivalent. However, we are not allowed to 402 // throw away these explicit instantiations. 403 if (Linkage == GVA_ExplicitTemplateInstantiation) 404 return llvm::Function::WeakODRLinkage; 405 406 // Otherwise, we have strong external linkage. 407 assert(Linkage == GVA_StrongExternal); 408 return llvm::Function::ExternalLinkage; 409} 410 411 412/// SetFunctionDefinitionAttributes - Set attributes for a global. 413/// 414/// FIXME: This is currently only done for aliases and functions, but not for 415/// variables (these details are set in EmitGlobalVarDefinition for variables). 416void CodeGenModule::SetFunctionDefinitionAttributes(const FunctionDecl *D, 417 llvm::GlobalValue *GV) { 418 SetCommonAttributes(D, GV); 419} 420 421void CodeGenModule::SetLLVMFunctionAttributes(const Decl *D, 422 const CGFunctionInfo &Info, 423 llvm::Function *F) { 424 unsigned CallingConv; 425 AttributeListType AttributeList; 426 ConstructAttributeList(Info, D, AttributeList, CallingConv); 427 F->setAttributes(llvm::AttrListPtr::get(AttributeList.begin(), 428 AttributeList.size())); 429 F->setCallingConv(static_cast<llvm::CallingConv::ID>(CallingConv)); 430} 431 432void CodeGenModule::SetLLVMFunctionAttributesForDefinition(const Decl *D, 433 llvm::Function *F) { 434 if (!Features.Exceptions && !Features.ObjCNonFragileABI) 435 F->addFnAttr(llvm::Attribute::NoUnwind); 436 437 if (D->hasAttr<AlwaysInlineAttr>()) 438 F->addFnAttr(llvm::Attribute::AlwaysInline); 439 440 if (D->hasAttr<NakedAttr>()) 441 F->addFnAttr(llvm::Attribute::Naked); 442 443 if (D->hasAttr<NoInlineAttr>()) 444 F->addFnAttr(llvm::Attribute::NoInline); 445 446 if (isa<CXXConstructorDecl>(D) || isa<CXXDestructorDecl>(D)) 447 F->setUnnamedAddr(true); 448 449 if (Features.getStackProtectorMode() == LangOptions::SSPOn) 450 F->addFnAttr(llvm::Attribute::StackProtect); 451 else if (Features.getStackProtectorMode() == LangOptions::SSPReq) 452 F->addFnAttr(llvm::Attribute::StackProtectReq); 453 454 unsigned alignment = D->getMaxAlignment() / Context.getCharWidth(); 455 if (alignment) 456 F->setAlignment(alignment); 457 458 // C++ ABI requires 2-byte alignment for member functions. 459 if (F->getAlignment() < 2 && isa<CXXMethodDecl>(D)) 460 F->setAlignment(2); 461} 462 463void CodeGenModule::SetCommonAttributes(const Decl *D, 464 llvm::GlobalValue *GV) { 465 if (isa<NamedDecl>(D)) 466 setGlobalVisibility(GV, cast<NamedDecl>(D), /*ForDef*/ true); 467 else 468 GV->setVisibility(llvm::GlobalValue::DefaultVisibility); 469 470 if (D->hasAttr<UsedAttr>()) 471 AddUsedGlobal(GV); 472 473 if (const SectionAttr *SA = D->getAttr<SectionAttr>()) 474 GV->setSection(SA->getName()); 475 476 getTargetCodeGenInfo().SetTargetAttributes(D, GV, *this); 477} 478 479void CodeGenModule::SetInternalFunctionAttributes(const Decl *D, 480 llvm::Function *F, 481 const CGFunctionInfo &FI) { 482 SetLLVMFunctionAttributes(D, FI, F); 483 SetLLVMFunctionAttributesForDefinition(D, F); 484 485 F->setLinkage(llvm::Function::InternalLinkage); 486 487 SetCommonAttributes(D, F); 488} 489 490void CodeGenModule::SetFunctionAttributes(GlobalDecl GD, 491 llvm::Function *F, 492 bool IsIncompleteFunction) { 493 const FunctionDecl *FD = cast<FunctionDecl>(GD.getDecl()); 494 495 if (!IsIncompleteFunction) 496 SetLLVMFunctionAttributes(FD, getTypes().getFunctionInfo(GD), F); 497 498 // Only a few attributes are set on declarations; these may later be 499 // overridden by a definition. 500 501 if (FD->hasAttr<DLLImportAttr>()) { 502 F->setLinkage(llvm::Function::DLLImportLinkage); 503 } else if (FD->hasAttr<WeakAttr>() || 504 FD->hasAttr<WeakImportAttr>()) { 505 // "extern_weak" is overloaded in LLVM; we probably should have 506 // separate linkage types for this. 507 F->setLinkage(llvm::Function::ExternalWeakLinkage); 508 } else { 509 F->setLinkage(llvm::Function::ExternalLinkage); 510 511 NamedDecl::LinkageInfo LV = FD->getLinkageAndVisibility(); 512 if (LV.linkage() == ExternalLinkage && LV.visibilityExplicit()) { 513 F->setVisibility(GetLLVMVisibility(LV.visibility())); 514 } 515 } 516 517 if (const SectionAttr *SA = FD->getAttr<SectionAttr>()) 518 F->setSection(SA->getName()); 519} 520 521void CodeGenModule::AddUsedGlobal(llvm::GlobalValue *GV) { 522 assert(!GV->isDeclaration() && 523 "Only globals with definition can force usage."); 524 LLVMUsed.push_back(GV); 525} 526 527void CodeGenModule::EmitLLVMUsed() { 528 // Don't create llvm.used if there is no need. 529 if (LLVMUsed.empty()) 530 return; 531 532 const llvm::Type *i8PTy = llvm::Type::getInt8PtrTy(VMContext); 533 534 // Convert LLVMUsed to what ConstantArray needs. 535 std::vector<llvm::Constant*> UsedArray; 536 UsedArray.resize(LLVMUsed.size()); 537 for (unsigned i = 0, e = LLVMUsed.size(); i != e; ++i) { 538 UsedArray[i] = 539 llvm::ConstantExpr::getBitCast(cast<llvm::Constant>(&*LLVMUsed[i]), 540 i8PTy); 541 } 542 543 if (UsedArray.empty()) 544 return; 545 llvm::ArrayType *ATy = llvm::ArrayType::get(i8PTy, UsedArray.size()); 546 547 llvm::GlobalVariable *GV = 548 new llvm::GlobalVariable(getModule(), ATy, false, 549 llvm::GlobalValue::AppendingLinkage, 550 llvm::ConstantArray::get(ATy, UsedArray), 551 "llvm.used"); 552 553 GV->setSection("llvm.metadata"); 554} 555 556void CodeGenModule::EmitDeferred() { 557 // Emit code for any potentially referenced deferred decls. Since a 558 // previously unused static decl may become used during the generation of code 559 // for a static function, iterate until no changes are made. 560 561 while (!DeferredDeclsToEmit.empty() || !DeferredVTables.empty()) { 562 if (!DeferredVTables.empty()) { 563 const CXXRecordDecl *RD = DeferredVTables.back(); 564 DeferredVTables.pop_back(); 565 getVTables().GenerateClassData(getVTableLinkage(RD), RD); 566 continue; 567 } 568 569 GlobalDecl D = DeferredDeclsToEmit.back(); 570 DeferredDeclsToEmit.pop_back(); 571 572 // Check to see if we've already emitted this. This is necessary 573 // for a couple of reasons: first, decls can end up in the 574 // deferred-decls queue multiple times, and second, decls can end 575 // up with definitions in unusual ways (e.g. by an extern inline 576 // function acquiring a strong function redefinition). Just 577 // ignore these cases. 578 // 579 // TODO: That said, looking this up multiple times is very wasteful. 580 llvm::StringRef Name = getMangledName(D); 581 llvm::GlobalValue *CGRef = GetGlobalValue(Name); 582 assert(CGRef && "Deferred decl wasn't referenced?"); 583 584 if (!CGRef->isDeclaration()) 585 continue; 586 587 // GlobalAlias::isDeclaration() defers to the aliasee, but for our 588 // purposes an alias counts as a definition. 589 if (isa<llvm::GlobalAlias>(CGRef)) 590 continue; 591 592 // Otherwise, emit the definition and move on to the next one. 593 EmitGlobalDefinition(D); 594 } 595} 596 597/// EmitAnnotateAttr - Generate the llvm::ConstantStruct which contains the 598/// annotation information for a given GlobalValue. The annotation struct is 599/// {i8 *, i8 *, i8 *, i32}. The first field is a constant expression, the 600/// GlobalValue being annotated. The second field is the constant string 601/// created from the AnnotateAttr's annotation. The third field is a constant 602/// string containing the name of the translation unit. The fourth field is 603/// the line number in the file of the annotated value declaration. 604/// 605/// FIXME: this does not unique the annotation string constants, as llvm-gcc 606/// appears to. 607/// 608llvm::Constant *CodeGenModule::EmitAnnotateAttr(llvm::GlobalValue *GV, 609 const AnnotateAttr *AA, 610 unsigned LineNo) { 611 llvm::Module *M = &getModule(); 612 613 // get [N x i8] constants for the annotation string, and the filename string 614 // which are the 2nd and 3rd elements of the global annotation structure. 615 const llvm::Type *SBP = llvm::Type::getInt8PtrTy(VMContext); 616 llvm::Constant *anno = llvm::ConstantArray::get(VMContext, 617 AA->getAnnotation(), true); 618 llvm::Constant *unit = llvm::ConstantArray::get(VMContext, 619 M->getModuleIdentifier(), 620 true); 621 622 // Get the two global values corresponding to the ConstantArrays we just 623 // created to hold the bytes of the strings. 624 llvm::GlobalValue *annoGV = 625 new llvm::GlobalVariable(*M, anno->getType(), false, 626 llvm::GlobalValue::PrivateLinkage, anno, 627 GV->getName()); 628 // translation unit name string, emitted into the llvm.metadata section. 629 llvm::GlobalValue *unitGV = 630 new llvm::GlobalVariable(*M, unit->getType(), false, 631 llvm::GlobalValue::PrivateLinkage, unit, 632 ".str"); 633 unitGV->setUnnamedAddr(true); 634 635 // Create the ConstantStruct for the global annotation. 636 llvm::Constant *Fields[4] = { 637 llvm::ConstantExpr::getBitCast(GV, SBP), 638 llvm::ConstantExpr::getBitCast(annoGV, SBP), 639 llvm::ConstantExpr::getBitCast(unitGV, SBP), 640 llvm::ConstantInt::get(llvm::Type::getInt32Ty(VMContext), LineNo) 641 }; 642 return llvm::ConstantStruct::get(VMContext, Fields, 4, false); 643} 644 645bool CodeGenModule::MayDeferGeneration(const ValueDecl *Global) { 646 // Never defer when EmitAllDecls is specified. 647 if (Features.EmitAllDecls) 648 return false; 649 650 return !getContext().DeclMustBeEmitted(Global); 651} 652 653llvm::Constant *CodeGenModule::GetWeakRefReference(const ValueDecl *VD) { 654 const AliasAttr *AA = VD->getAttr<AliasAttr>(); 655 assert(AA && "No alias?"); 656 657 const llvm::Type *DeclTy = getTypes().ConvertTypeForMem(VD->getType()); 658 659 // See if there is already something with the target's name in the module. 660 llvm::GlobalValue *Entry = GetGlobalValue(AA->getAliasee()); 661 662 llvm::Constant *Aliasee; 663 if (isa<llvm::FunctionType>(DeclTy)) 664 Aliasee = GetOrCreateLLVMFunction(AA->getAliasee(), DeclTy, GlobalDecl()); 665 else 666 Aliasee = GetOrCreateLLVMGlobal(AA->getAliasee(), 667 llvm::PointerType::getUnqual(DeclTy), 0); 668 if (!Entry) { 669 llvm::GlobalValue* F = cast<llvm::GlobalValue>(Aliasee); 670 F->setLinkage(llvm::Function::ExternalWeakLinkage); 671 WeakRefReferences.insert(F); 672 } 673 674 return Aliasee; 675} 676 677void CodeGenModule::EmitGlobal(GlobalDecl GD) { 678 const ValueDecl *Global = cast<ValueDecl>(GD.getDecl()); 679 680 // Weak references don't produce any output by themselves. 681 if (Global->hasAttr<WeakRefAttr>()) 682 return; 683 684 // If this is an alias definition (which otherwise looks like a declaration) 685 // emit it now. 686 if (Global->hasAttr<AliasAttr>()) 687 return EmitAliasDefinition(GD); 688 689 // Ignore declarations, they will be emitted on their first use. 690 if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(Global)) { 691 if (FD->getIdentifier()) { 692 llvm::StringRef Name = FD->getName(); 693 if (Name == "_Block_object_assign") { 694 BlockObjectAssignDecl = FD; 695 } else if (Name == "_Block_object_dispose") { 696 BlockObjectDisposeDecl = FD; 697 } 698 } 699 700 // Forward declarations are emitted lazily on first use. 701 if (!FD->isThisDeclarationADefinition()) 702 return; 703 } else { 704 const VarDecl *VD = cast<VarDecl>(Global); 705 assert(VD->isFileVarDecl() && "Cannot emit local var decl as global."); 706 707 if (VD->getIdentifier()) { 708 llvm::StringRef Name = VD->getName(); 709 if (Name == "_NSConcreteGlobalBlock") { 710 NSConcreteGlobalBlockDecl = VD; 711 } else if (Name == "_NSConcreteStackBlock") { 712 NSConcreteStackBlockDecl = VD; 713 } 714 } 715 716 717 if (VD->isThisDeclarationADefinition() != VarDecl::Definition) 718 return; 719 } 720 721 // Defer code generation when possible if this is a static definition, inline 722 // function etc. These we only want to emit if they are used. 723 if (!MayDeferGeneration(Global)) { 724 // Emit the definition if it can't be deferred. 725 EmitGlobalDefinition(GD); 726 return; 727 } 728 729 // If we're deferring emission of a C++ variable with an 730 // initializer, remember the order in which it appeared in the file. 731 if (getLangOptions().CPlusPlus && isa<VarDecl>(Global) && 732 cast<VarDecl>(Global)->hasInit()) { 733 DelayedCXXInitPosition[Global] = CXXGlobalInits.size(); 734 CXXGlobalInits.push_back(0); 735 } 736 737 // If the value has already been used, add it directly to the 738 // DeferredDeclsToEmit list. 739 llvm::StringRef MangledName = getMangledName(GD); 740 if (GetGlobalValue(MangledName)) 741 DeferredDeclsToEmit.push_back(GD); 742 else { 743 // Otherwise, remember that we saw a deferred decl with this name. The 744 // first use of the mangled name will cause it to move into 745 // DeferredDeclsToEmit. 746 DeferredDecls[MangledName] = GD; 747 } 748} 749 750void CodeGenModule::EmitGlobalDefinition(GlobalDecl GD) { 751 const ValueDecl *D = cast<ValueDecl>(GD.getDecl()); 752 753 PrettyStackTraceDecl CrashInfo(const_cast<ValueDecl *>(D), D->getLocation(), 754 Context.getSourceManager(), 755 "Generating code for declaration"); 756 757 if (const FunctionDecl *Function = dyn_cast<FunctionDecl>(D)) { 758 // At -O0, don't generate IR for functions with available_externally 759 // linkage. 760 if (CodeGenOpts.OptimizationLevel == 0 && 761 !Function->hasAttr<AlwaysInlineAttr>() && 762 getFunctionLinkage(Function) 763 == llvm::Function::AvailableExternallyLinkage) 764 return; 765 766 if (const CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(D)) { 767 if (Method->isVirtual()) 768 getVTables().EmitThunks(GD); 769 770 if (const CXXConstructorDecl *CD = dyn_cast<CXXConstructorDecl>(Method)) 771 return EmitCXXConstructor(CD, GD.getCtorType()); 772 773 if (const CXXDestructorDecl *DD = dyn_cast<CXXDestructorDecl>(Method)) 774 return EmitCXXDestructor(DD, GD.getDtorType()); 775 } 776 777 return EmitGlobalFunctionDefinition(GD); 778 } 779 780 if (const VarDecl *VD = dyn_cast<VarDecl>(D)) 781 return EmitGlobalVarDefinition(VD); 782 783 assert(0 && "Invalid argument to EmitGlobalDefinition()"); 784} 785 786/// GetOrCreateLLVMFunction - If the specified mangled name is not in the 787/// module, create and return an llvm Function with the specified type. If there 788/// is something in the module with the specified name, return it potentially 789/// bitcasted to the right type. 790/// 791/// If D is non-null, it specifies a decl that correspond to this. This is used 792/// to set the attributes on the function when it is first created. 793llvm::Constant * 794CodeGenModule::GetOrCreateLLVMFunction(llvm::StringRef MangledName, 795 const llvm::Type *Ty, 796 GlobalDecl D) { 797 // Lookup the entry, lazily creating it if necessary. 798 llvm::GlobalValue *Entry = GetGlobalValue(MangledName); 799 if (Entry) { 800 if (WeakRefReferences.count(Entry)) { 801 const FunctionDecl *FD = cast_or_null<FunctionDecl>(D.getDecl()); 802 if (FD && !FD->hasAttr<WeakAttr>()) 803 Entry->setLinkage(llvm::Function::ExternalLinkage); 804 805 WeakRefReferences.erase(Entry); 806 } 807 808 if (Entry->getType()->getElementType() == Ty) 809 return Entry; 810 811 // Make sure the result is of the correct type. 812 const llvm::Type *PTy = llvm::PointerType::getUnqual(Ty); 813 return llvm::ConstantExpr::getBitCast(Entry, PTy); 814 } 815 816 // This function doesn't have a complete type (for example, the return 817 // type is an incomplete struct). Use a fake type instead, and make 818 // sure not to try to set attributes. 819 bool IsIncompleteFunction = false; 820 821 const llvm::FunctionType *FTy; 822 if (isa<llvm::FunctionType>(Ty)) { 823 FTy = cast<llvm::FunctionType>(Ty); 824 } else { 825 FTy = llvm::FunctionType::get(llvm::Type::getVoidTy(VMContext), 826 std::vector<const llvm::Type*>(), false); 827 IsIncompleteFunction = true; 828 } 829 830 llvm::Function *F = llvm::Function::Create(FTy, 831 llvm::Function::ExternalLinkage, 832 MangledName, &getModule()); 833 assert(F->getName() == MangledName && "name was uniqued!"); 834 if (D.getDecl()) 835 SetFunctionAttributes(D, F, IsIncompleteFunction); 836 837 // This is the first use or definition of a mangled name. If there is a 838 // deferred decl with this name, remember that we need to emit it at the end 839 // of the file. 840 llvm::StringMap<GlobalDecl>::iterator DDI = DeferredDecls.find(MangledName); 841 if (DDI != DeferredDecls.end()) { 842 // Move the potentially referenced deferred decl to the DeferredDeclsToEmit 843 // list, and remove it from DeferredDecls (since we don't need it anymore). 844 DeferredDeclsToEmit.push_back(DDI->second); 845 DeferredDecls.erase(DDI); 846 847 // Otherwise, there are cases we have to worry about where we're 848 // using a declaration for which we must emit a definition but where 849 // we might not find a top-level definition: 850 // - member functions defined inline in their classes 851 // - friend functions defined inline in some class 852 // - special member functions with implicit definitions 853 // If we ever change our AST traversal to walk into class methods, 854 // this will be unnecessary. 855 } else if (getLangOptions().CPlusPlus && D.getDecl()) { 856 // Look for a declaration that's lexically in a record. 857 const FunctionDecl *FD = cast<FunctionDecl>(D.getDecl()); 858 do { 859 if (isa<CXXRecordDecl>(FD->getLexicalDeclContext())) { 860 if (FD->isImplicit()) { 861 assert(FD->isUsed() && "Sema didn't mark implicit function as used!"); 862 DeferredDeclsToEmit.push_back(D); 863 break; 864 } else if (FD->isThisDeclarationADefinition()) { 865 DeferredDeclsToEmit.push_back(D); 866 break; 867 } 868 } 869 FD = FD->getPreviousDeclaration(); 870 } while (FD); 871 } 872 873 // Make sure the result is of the requested type. 874 if (!IsIncompleteFunction) { 875 assert(F->getType()->getElementType() == Ty); 876 return F; 877 } 878 879 const llvm::Type *PTy = llvm::PointerType::getUnqual(Ty); 880 return llvm::ConstantExpr::getBitCast(F, PTy); 881} 882 883/// GetAddrOfFunction - Return the address of the given function. If Ty is 884/// non-null, then this function will use the specified type if it has to 885/// create it (this occurs when we see a definition of the function). 886llvm::Constant *CodeGenModule::GetAddrOfFunction(GlobalDecl GD, 887 const llvm::Type *Ty) { 888 // If there was no specific requested type, just convert it now. 889 if (!Ty) 890 Ty = getTypes().ConvertType(cast<ValueDecl>(GD.getDecl())->getType()); 891 892 llvm::StringRef MangledName = getMangledName(GD); 893 return GetOrCreateLLVMFunction(MangledName, Ty, GD); 894} 895 896/// CreateRuntimeFunction - Create a new runtime function with the specified 897/// type and name. 898llvm::Constant * 899CodeGenModule::CreateRuntimeFunction(const llvm::FunctionType *FTy, 900 llvm::StringRef Name) { 901 return GetOrCreateLLVMFunction(Name, FTy, GlobalDecl()); 902} 903 904static bool DeclIsConstantGlobal(ASTContext &Context, const VarDecl *D) { 905 if (!D->getType().isConstant(Context) && !D->getType()->isReferenceType()) 906 return false; 907 if (Context.getLangOptions().CPlusPlus && 908 Context.getBaseElementType(D->getType())->getAs<RecordType>()) { 909 // FIXME: We should do something fancier here! 910 return false; 911 } 912 return true; 913} 914 915/// GetOrCreateLLVMGlobal - If the specified mangled name is not in the module, 916/// create and return an llvm GlobalVariable with the specified type. If there 917/// is something in the module with the specified name, return it potentially 918/// bitcasted to the right type. 919/// 920/// If D is non-null, it specifies a decl that correspond to this. This is used 921/// to set the attributes on the global when it is first created. 922llvm::Constant * 923CodeGenModule::GetOrCreateLLVMGlobal(llvm::StringRef MangledName, 924 const llvm::PointerType *Ty, 925 const VarDecl *D, 926 bool UnnamedAddr) { 927 // Lookup the entry, lazily creating it if necessary. 928 llvm::GlobalValue *Entry = GetGlobalValue(MangledName); 929 if (Entry) { 930 if (WeakRefReferences.count(Entry)) { 931 if (D && !D->hasAttr<WeakAttr>()) 932 Entry->setLinkage(llvm::Function::ExternalLinkage); 933 934 WeakRefReferences.erase(Entry); 935 } 936 937 if (UnnamedAddr) 938 Entry->setUnnamedAddr(true); 939 940 if (Entry->getType() == Ty) 941 return Entry; 942 943 // Make sure the result is of the correct type. 944 return llvm::ConstantExpr::getBitCast(Entry, Ty); 945 } 946 947 // This is the first use or definition of a mangled name. If there is a 948 // deferred decl with this name, remember that we need to emit it at the end 949 // of the file. 950 llvm::StringMap<GlobalDecl>::iterator DDI = DeferredDecls.find(MangledName); 951 if (DDI != DeferredDecls.end()) { 952 // Move the potentially referenced deferred decl to the DeferredDeclsToEmit 953 // list, and remove it from DeferredDecls (since we don't need it anymore). 954 DeferredDeclsToEmit.push_back(DDI->second); 955 DeferredDecls.erase(DDI); 956 } 957 958 llvm::GlobalVariable *GV = 959 new llvm::GlobalVariable(getModule(), Ty->getElementType(), false, 960 llvm::GlobalValue::ExternalLinkage, 961 0, MangledName, 0, 962 false, Ty->getAddressSpace()); 963 964 // Handle things which are present even on external declarations. 965 if (D) { 966 // FIXME: This code is overly simple and should be merged with other global 967 // handling. 968 GV->setConstant(DeclIsConstantGlobal(Context, D)); 969 970 // Set linkage and visibility in case we never see a definition. 971 NamedDecl::LinkageInfo LV = D->getLinkageAndVisibility(); 972 if (LV.linkage() != ExternalLinkage) { 973 GV->setLinkage(llvm::GlobalValue::InternalLinkage); 974 } else { 975 if (D->hasAttr<DLLImportAttr>()) 976 GV->setLinkage(llvm::GlobalValue::DLLImportLinkage); 977 else if (D->hasAttr<WeakAttr>() || D->hasAttr<WeakImportAttr>()) 978 GV->setLinkage(llvm::GlobalValue::ExternalWeakLinkage); 979 980 // Set visibility on a declaration only if it's explicit. 981 if (LV.visibilityExplicit()) 982 GV->setVisibility(GetLLVMVisibility(LV.visibility())); 983 } 984 985 GV->setThreadLocal(D->isThreadSpecified()); 986 } 987 988 return GV; 989} 990 991 992/// GetAddrOfGlobalVar - Return the llvm::Constant for the address of the 993/// given global variable. If Ty is non-null and if the global doesn't exist, 994/// then it will be greated with the specified type instead of whatever the 995/// normal requested type would be. 996llvm::Constant *CodeGenModule::GetAddrOfGlobalVar(const VarDecl *D, 997 const llvm::Type *Ty) { 998 assert(D->hasGlobalStorage() && "Not a global variable"); 999 QualType ASTTy = D->getType(); 1000 if (Ty == 0) 1001 Ty = getTypes().ConvertTypeForMem(ASTTy); 1002 1003 const llvm::PointerType *PTy = 1004 llvm::PointerType::get(Ty, ASTTy.getAddressSpace()); 1005 1006 llvm::StringRef MangledName = getMangledName(D); 1007 return GetOrCreateLLVMGlobal(MangledName, PTy, D); 1008} 1009 1010/// CreateRuntimeVariable - Create a new runtime global variable with the 1011/// specified type and name. 1012llvm::Constant * 1013CodeGenModule::CreateRuntimeVariable(const llvm::Type *Ty, 1014 llvm::StringRef Name) { 1015 return GetOrCreateLLVMGlobal(Name, llvm::PointerType::getUnqual(Ty), 0, 1016 true); 1017} 1018 1019void CodeGenModule::EmitTentativeDefinition(const VarDecl *D) { 1020 assert(!D->getInit() && "Cannot emit definite definitions here!"); 1021 1022 if (MayDeferGeneration(D)) { 1023 // If we have not seen a reference to this variable yet, place it 1024 // into the deferred declarations table to be emitted if needed 1025 // later. 1026 llvm::StringRef MangledName = getMangledName(D); 1027 if (!GetGlobalValue(MangledName)) { 1028 DeferredDecls[MangledName] = D; 1029 return; 1030 } 1031 } 1032 1033 // The tentative definition is the only definition. 1034 EmitGlobalVarDefinition(D); 1035} 1036 1037void CodeGenModule::EmitVTable(CXXRecordDecl *Class, bool DefinitionRequired) { 1038 if (DefinitionRequired) 1039 getVTables().GenerateClassData(getVTableLinkage(Class), Class); 1040} 1041 1042llvm::GlobalVariable::LinkageTypes 1043CodeGenModule::getVTableLinkage(const CXXRecordDecl *RD) { 1044 if (RD->isInAnonymousNamespace() || !RD->hasLinkage()) 1045 return llvm::GlobalVariable::InternalLinkage; 1046 1047 if (const CXXMethodDecl *KeyFunction 1048 = RD->getASTContext().getKeyFunction(RD)) { 1049 // If this class has a key function, use that to determine the linkage of 1050 // the vtable. 1051 const FunctionDecl *Def = 0; 1052 if (KeyFunction->hasBody(Def)) 1053 KeyFunction = cast<CXXMethodDecl>(Def); 1054 1055 switch (KeyFunction->getTemplateSpecializationKind()) { 1056 case TSK_Undeclared: 1057 case TSK_ExplicitSpecialization: 1058 if (KeyFunction->isInlined()) 1059 return llvm::GlobalVariable::WeakODRLinkage; 1060 1061 return llvm::GlobalVariable::ExternalLinkage; 1062 1063 case TSK_ImplicitInstantiation: 1064 case TSK_ExplicitInstantiationDefinition: 1065 return llvm::GlobalVariable::WeakODRLinkage; 1066 1067 case TSK_ExplicitInstantiationDeclaration: 1068 // FIXME: Use available_externally linkage. However, this currently 1069 // breaks LLVM's build due to undefined symbols. 1070 // return llvm::GlobalVariable::AvailableExternallyLinkage; 1071 return llvm::GlobalVariable::WeakODRLinkage; 1072 } 1073 } 1074 1075 switch (RD->getTemplateSpecializationKind()) { 1076 case TSK_Undeclared: 1077 case TSK_ExplicitSpecialization: 1078 case TSK_ImplicitInstantiation: 1079 case TSK_ExplicitInstantiationDefinition: 1080 return llvm::GlobalVariable::WeakODRLinkage; 1081 1082 case TSK_ExplicitInstantiationDeclaration: 1083 // FIXME: Use available_externally linkage. However, this currently 1084 // breaks LLVM's build due to undefined symbols. 1085 // return llvm::GlobalVariable::AvailableExternallyLinkage; 1086 return llvm::GlobalVariable::WeakODRLinkage; 1087 } 1088 1089 // Silence GCC warning. 1090 return llvm::GlobalVariable::WeakODRLinkage; 1091} 1092 1093CharUnits CodeGenModule::GetTargetTypeStoreSize(const llvm::Type *Ty) const { 1094 return Context.toCharUnitsFromBits( 1095 TheTargetData.getTypeStoreSizeInBits(Ty)); 1096} 1097 1098void CodeGenModule::EmitGlobalVarDefinition(const VarDecl *D) { 1099 llvm::Constant *Init = 0; 1100 QualType ASTTy = D->getType(); 1101 bool NonConstInit = false; 1102 1103 const Expr *InitExpr = D->getAnyInitializer(); 1104 1105 if (!InitExpr) { 1106 // This is a tentative definition; tentative definitions are 1107 // implicitly initialized with { 0 }. 1108 // 1109 // Note that tentative definitions are only emitted at the end of 1110 // a translation unit, so they should never have incomplete 1111 // type. In addition, EmitTentativeDefinition makes sure that we 1112 // never attempt to emit a tentative definition if a real one 1113 // exists. A use may still exists, however, so we still may need 1114 // to do a RAUW. 1115 assert(!ASTTy->isIncompleteType() && "Unexpected incomplete type"); 1116 Init = EmitNullConstant(D->getType()); 1117 } else { 1118 Init = EmitConstantExpr(InitExpr, D->getType()); 1119 if (!Init) { 1120 QualType T = InitExpr->getType(); 1121 if (D->getType()->isReferenceType()) 1122 T = D->getType(); 1123 1124 if (getLangOptions().CPlusPlus) { 1125 Init = EmitNullConstant(T); 1126 NonConstInit = true; 1127 } else { 1128 ErrorUnsupported(D, "static initializer"); 1129 Init = llvm::UndefValue::get(getTypes().ConvertType(T)); 1130 } 1131 } else { 1132 // We don't need an initializer, so remove the entry for the delayed 1133 // initializer position (just in case this entry was delayed). 1134 if (getLangOptions().CPlusPlus) 1135 DelayedCXXInitPosition.erase(D); 1136 } 1137 } 1138 1139 const llvm::Type* InitType = Init->getType(); 1140 llvm::Constant *Entry = GetAddrOfGlobalVar(D, InitType); 1141 1142 // Strip off a bitcast if we got one back. 1143 if (llvm::ConstantExpr *CE = dyn_cast<llvm::ConstantExpr>(Entry)) { 1144 assert(CE->getOpcode() == llvm::Instruction::BitCast || 1145 // all zero index gep. 1146 CE->getOpcode() == llvm::Instruction::GetElementPtr); 1147 Entry = CE->getOperand(0); 1148 } 1149 1150 // Entry is now either a Function or GlobalVariable. 1151 llvm::GlobalVariable *GV = dyn_cast<llvm::GlobalVariable>(Entry); 1152 1153 // We have a definition after a declaration with the wrong type. 1154 // We must make a new GlobalVariable* and update everything that used OldGV 1155 // (a declaration or tentative definition) with the new GlobalVariable* 1156 // (which will be a definition). 1157 // 1158 // This happens if there is a prototype for a global (e.g. 1159 // "extern int x[];") and then a definition of a different type (e.g. 1160 // "int x[10];"). This also happens when an initializer has a different type 1161 // from the type of the global (this happens with unions). 1162 if (GV == 0 || 1163 GV->getType()->getElementType() != InitType || 1164 GV->getType()->getAddressSpace() != ASTTy.getAddressSpace()) { 1165 1166 // Move the old entry aside so that we'll create a new one. 1167 Entry->setName(llvm::StringRef()); 1168 1169 // Make a new global with the correct type, this is now guaranteed to work. 1170 GV = cast<llvm::GlobalVariable>(GetAddrOfGlobalVar(D, InitType)); 1171 1172 // Replace all uses of the old global with the new global 1173 llvm::Constant *NewPtrForOldDecl = 1174 llvm::ConstantExpr::getBitCast(GV, Entry->getType()); 1175 Entry->replaceAllUsesWith(NewPtrForOldDecl); 1176 1177 // Erase the old global, since it is no longer used. 1178 cast<llvm::GlobalValue>(Entry)->eraseFromParent(); 1179 } 1180 1181 if (const AnnotateAttr *AA = D->getAttr<AnnotateAttr>()) { 1182 SourceManager &SM = Context.getSourceManager(); 1183 AddAnnotation(EmitAnnotateAttr(GV, AA, 1184 SM.getInstantiationLineNumber(D->getLocation()))); 1185 } 1186 1187 GV->setInitializer(Init); 1188 1189 // If it is safe to mark the global 'constant', do so now. 1190 GV->setConstant(false); 1191 if (!NonConstInit && DeclIsConstantGlobal(Context, D)) 1192 GV->setConstant(true); 1193 1194 GV->setAlignment(getContext().getDeclAlign(D).getQuantity()); 1195 1196 // Set the llvm linkage type as appropriate. 1197 llvm::GlobalValue::LinkageTypes Linkage = 1198 GetLLVMLinkageVarDefinition(D, GV); 1199 GV->setLinkage(Linkage); 1200 if (Linkage == llvm::GlobalVariable::CommonLinkage) 1201 // common vars aren't constant even if declared const. 1202 GV->setConstant(false); 1203 1204 SetCommonAttributes(D, GV); 1205 1206 // Emit the initializer function if necessary. 1207 if (NonConstInit) 1208 EmitCXXGlobalVarDeclInitFunc(D, GV); 1209 1210 // Emit global variable debug information. 1211 if (CGDebugInfo *DI = getDebugInfo()) { 1212 DI->setLocation(D->getLocation()); 1213 DI->EmitGlobalVariable(GV, D); 1214 } 1215} 1216 1217llvm::GlobalValue::LinkageTypes 1218CodeGenModule::GetLLVMLinkageVarDefinition(const VarDecl *D, 1219 llvm::GlobalVariable *GV) { 1220 GVALinkage Linkage = getContext().GetGVALinkageForVariable(D); 1221 if (Linkage == GVA_Internal) 1222 return llvm::Function::InternalLinkage; 1223 else if (D->hasAttr<DLLImportAttr>()) 1224 return llvm::Function::DLLImportLinkage; 1225 else if (D->hasAttr<DLLExportAttr>()) 1226 return llvm::Function::DLLExportLinkage; 1227 else if (D->hasAttr<WeakAttr>()) { 1228 if (GV->isConstant()) 1229 return llvm::GlobalVariable::WeakODRLinkage; 1230 else 1231 return llvm::GlobalVariable::WeakAnyLinkage; 1232 } else if (Linkage == GVA_TemplateInstantiation || 1233 Linkage == GVA_ExplicitTemplateInstantiation) 1234 // FIXME: It seems like we can provide more specific linkage here 1235 // (LinkOnceODR, WeakODR). 1236 return llvm::GlobalVariable::WeakAnyLinkage; 1237 else if (!getLangOptions().CPlusPlus && 1238 ((!CodeGenOpts.NoCommon && !D->getAttr<NoCommonAttr>()) || 1239 D->getAttr<CommonAttr>()) && 1240 !D->hasExternalStorage() && !D->getInit() && 1241 !D->getAttr<SectionAttr>() && !D->isThreadSpecified()) { 1242 // Thread local vars aren't considered common linkage. 1243 return llvm::GlobalVariable::CommonLinkage; 1244 } 1245 return llvm::GlobalVariable::ExternalLinkage; 1246} 1247 1248/// ReplaceUsesOfNonProtoTypeWithRealFunction - This function is called when we 1249/// implement a function with no prototype, e.g. "int foo() {}". If there are 1250/// existing call uses of the old function in the module, this adjusts them to 1251/// call the new function directly. 1252/// 1253/// This is not just a cleanup: the always_inline pass requires direct calls to 1254/// functions to be able to inline them. If there is a bitcast in the way, it 1255/// won't inline them. Instcombine normally deletes these calls, but it isn't 1256/// run at -O0. 1257static void ReplaceUsesOfNonProtoTypeWithRealFunction(llvm::GlobalValue *Old, 1258 llvm::Function *NewFn) { 1259 // If we're redefining a global as a function, don't transform it. 1260 llvm::Function *OldFn = dyn_cast<llvm::Function>(Old); 1261 if (OldFn == 0) return; 1262 1263 const llvm::Type *NewRetTy = NewFn->getReturnType(); 1264 llvm::SmallVector<llvm::Value*, 4> ArgList; 1265 1266 for (llvm::Value::use_iterator UI = OldFn->use_begin(), E = OldFn->use_end(); 1267 UI != E; ) { 1268 // TODO: Do invokes ever occur in C code? If so, we should handle them too. 1269 llvm::Value::use_iterator I = UI++; // Increment before the CI is erased. 1270 llvm::CallInst *CI = dyn_cast<llvm::CallInst>(*I); 1271 if (!CI) continue; // FIXME: when we allow Invoke, just do CallSite CS(*I) 1272 llvm::CallSite CS(CI); 1273 if (!CI || !CS.isCallee(I)) continue; 1274 1275 // If the return types don't match exactly, and if the call isn't dead, then 1276 // we can't transform this call. 1277 if (CI->getType() != NewRetTy && !CI->use_empty()) 1278 continue; 1279 1280 // If the function was passed too few arguments, don't transform. If extra 1281 // arguments were passed, we silently drop them. If any of the types 1282 // mismatch, we don't transform. 1283 unsigned ArgNo = 0; 1284 bool DontTransform = false; 1285 for (llvm::Function::arg_iterator AI = NewFn->arg_begin(), 1286 E = NewFn->arg_end(); AI != E; ++AI, ++ArgNo) { 1287 if (CS.arg_size() == ArgNo || 1288 CS.getArgument(ArgNo)->getType() != AI->getType()) { 1289 DontTransform = true; 1290 break; 1291 } 1292 } 1293 if (DontTransform) 1294 continue; 1295 1296 // Okay, we can transform this. Create the new call instruction and copy 1297 // over the required information. 1298 ArgList.append(CS.arg_begin(), CS.arg_begin() + ArgNo); 1299 llvm::CallInst *NewCall = llvm::CallInst::Create(NewFn, ArgList.begin(), 1300 ArgList.end(), "", CI); 1301 ArgList.clear(); 1302 if (!NewCall->getType()->isVoidTy()) 1303 NewCall->takeName(CI); 1304 NewCall->setAttributes(CI->getAttributes()); 1305 NewCall->setCallingConv(CI->getCallingConv()); 1306 1307 // Finally, remove the old call, replacing any uses with the new one. 1308 if (!CI->use_empty()) 1309 CI->replaceAllUsesWith(NewCall); 1310 1311 // Copy debug location attached to CI. 1312 if (!CI->getDebugLoc().isUnknown()) 1313 NewCall->setDebugLoc(CI->getDebugLoc()); 1314 CI->eraseFromParent(); 1315 } 1316} 1317 1318 1319void CodeGenModule::EmitGlobalFunctionDefinition(GlobalDecl GD) { 1320 const FunctionDecl *D = cast<FunctionDecl>(GD.getDecl()); 1321 const llvm::FunctionType *Ty = getTypes().GetFunctionType(GD); 1322 // Get or create the prototype for the function. 1323 llvm::Constant *Entry = GetAddrOfFunction(GD, Ty); 1324 1325 // Strip off a bitcast if we got one back. 1326 if (llvm::ConstantExpr *CE = dyn_cast<llvm::ConstantExpr>(Entry)) { 1327 assert(CE->getOpcode() == llvm::Instruction::BitCast); 1328 Entry = CE->getOperand(0); 1329 } 1330 1331 1332 if (cast<llvm::GlobalValue>(Entry)->getType()->getElementType() != Ty) { 1333 llvm::GlobalValue *OldFn = cast<llvm::GlobalValue>(Entry); 1334 1335 // If the types mismatch then we have to rewrite the definition. 1336 assert(OldFn->isDeclaration() && 1337 "Shouldn't replace non-declaration"); 1338 1339 // F is the Function* for the one with the wrong type, we must make a new 1340 // Function* and update everything that used F (a declaration) with the new 1341 // Function* (which will be a definition). 1342 // 1343 // This happens if there is a prototype for a function 1344 // (e.g. "int f()") and then a definition of a different type 1345 // (e.g. "int f(int x)"). Move the old function aside so that it 1346 // doesn't interfere with GetAddrOfFunction. 1347 OldFn->setName(llvm::StringRef()); 1348 llvm::Function *NewFn = cast<llvm::Function>(GetAddrOfFunction(GD, Ty)); 1349 1350 // If this is an implementation of a function without a prototype, try to 1351 // replace any existing uses of the function (which may be calls) with uses 1352 // of the new function 1353 if (D->getType()->isFunctionNoProtoType()) { 1354 ReplaceUsesOfNonProtoTypeWithRealFunction(OldFn, NewFn); 1355 OldFn->removeDeadConstantUsers(); 1356 } 1357 1358 // Replace uses of F with the Function we will endow with a body. 1359 if (!Entry->use_empty()) { 1360 llvm::Constant *NewPtrForOldDecl = 1361 llvm::ConstantExpr::getBitCast(NewFn, Entry->getType()); 1362 Entry->replaceAllUsesWith(NewPtrForOldDecl); 1363 } 1364 1365 // Ok, delete the old function now, which is dead. 1366 OldFn->eraseFromParent(); 1367 1368 Entry = NewFn; 1369 } 1370 1371 // We need to set linkage and visibility on the function before 1372 // generating code for it because various parts of IR generation 1373 // want to propagate this information down (e.g. to local static 1374 // declarations). 1375 llvm::Function *Fn = cast<llvm::Function>(Entry); 1376 setFunctionLinkage(D, Fn); 1377 1378 // FIXME: this is redundant with part of SetFunctionDefinitionAttributes 1379 setGlobalVisibility(Fn, D, /*ForDef*/ true); 1380 1381 CodeGenFunction(*this).GenerateCode(D, Fn); 1382 1383 SetFunctionDefinitionAttributes(D, Fn); 1384 SetLLVMFunctionAttributesForDefinition(D, Fn); 1385 1386 if (const ConstructorAttr *CA = D->getAttr<ConstructorAttr>()) 1387 AddGlobalCtor(Fn, CA->getPriority()); 1388 if (const DestructorAttr *DA = D->getAttr<DestructorAttr>()) 1389 AddGlobalDtor(Fn, DA->getPriority()); 1390} 1391 1392void CodeGenModule::EmitAliasDefinition(GlobalDecl GD) { 1393 const ValueDecl *D = cast<ValueDecl>(GD.getDecl()); 1394 const AliasAttr *AA = D->getAttr<AliasAttr>(); 1395 assert(AA && "Not an alias?"); 1396 1397 llvm::StringRef MangledName = getMangledName(GD); 1398 1399 // If there is a definition in the module, then it wins over the alias. 1400 // This is dubious, but allow it to be safe. Just ignore the alias. 1401 llvm::GlobalValue *Entry = GetGlobalValue(MangledName); 1402 if (Entry && !Entry->isDeclaration()) 1403 return; 1404 1405 const llvm::Type *DeclTy = getTypes().ConvertTypeForMem(D->getType()); 1406 1407 // Create a reference to the named value. This ensures that it is emitted 1408 // if a deferred decl. 1409 llvm::Constant *Aliasee; 1410 if (isa<llvm::FunctionType>(DeclTy)) 1411 Aliasee = GetOrCreateLLVMFunction(AA->getAliasee(), DeclTy, GlobalDecl()); 1412 else 1413 Aliasee = GetOrCreateLLVMGlobal(AA->getAliasee(), 1414 llvm::PointerType::getUnqual(DeclTy), 0); 1415 1416 // Create the new alias itself, but don't set a name yet. 1417 llvm::GlobalValue *GA = 1418 new llvm::GlobalAlias(Aliasee->getType(), 1419 llvm::Function::ExternalLinkage, 1420 "", Aliasee, &getModule()); 1421 1422 if (Entry) { 1423 assert(Entry->isDeclaration()); 1424 1425 // If there is a declaration in the module, then we had an extern followed 1426 // by the alias, as in: 1427 // extern int test6(); 1428 // ... 1429 // int test6() __attribute__((alias("test7"))); 1430 // 1431 // Remove it and replace uses of it with the alias. 1432 GA->takeName(Entry); 1433 1434 Entry->replaceAllUsesWith(llvm::ConstantExpr::getBitCast(GA, 1435 Entry->getType())); 1436 Entry->eraseFromParent(); 1437 } else { 1438 GA->setName(MangledName); 1439 } 1440 1441 // Set attributes which are particular to an alias; this is a 1442 // specialization of the attributes which may be set on a global 1443 // variable/function. 1444 if (D->hasAttr<DLLExportAttr>()) { 1445 if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) { 1446 // The dllexport attribute is ignored for undefined symbols. 1447 if (FD->hasBody()) 1448 GA->setLinkage(llvm::Function::DLLExportLinkage); 1449 } else { 1450 GA->setLinkage(llvm::Function::DLLExportLinkage); 1451 } 1452 } else if (D->hasAttr<WeakAttr>() || 1453 D->hasAttr<WeakRefAttr>() || 1454 D->hasAttr<WeakImportAttr>()) { 1455 GA->setLinkage(llvm::Function::WeakAnyLinkage); 1456 } 1457 1458 SetCommonAttributes(D, GA); 1459} 1460 1461/// getBuiltinLibFunction - Given a builtin id for a function like 1462/// "__builtin_fabsf", return a Function* for "fabsf". 1463llvm::Value *CodeGenModule::getBuiltinLibFunction(const FunctionDecl *FD, 1464 unsigned BuiltinID) { 1465 assert((Context.BuiltinInfo.isLibFunction(BuiltinID) || 1466 Context.BuiltinInfo.isPredefinedLibFunction(BuiltinID)) && 1467 "isn't a lib fn"); 1468 1469 // Get the name, skip over the __builtin_ prefix (if necessary). 1470 const char *Name = Context.BuiltinInfo.GetName(BuiltinID); 1471 if (Context.BuiltinInfo.isLibFunction(BuiltinID)) 1472 Name += 10; 1473 1474 const llvm::FunctionType *Ty = 1475 cast<llvm::FunctionType>(getTypes().ConvertType(FD->getType())); 1476 1477 return GetOrCreateLLVMFunction(Name, Ty, GlobalDecl(FD)); 1478} 1479 1480llvm::Function *CodeGenModule::getIntrinsic(unsigned IID,const llvm::Type **Tys, 1481 unsigned NumTys) { 1482 return llvm::Intrinsic::getDeclaration(&getModule(), 1483 (llvm::Intrinsic::ID)IID, Tys, NumTys); 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 GV->setUnnamedAddr(true); 1599 if (isUTF16) { 1600 CharUnits Align = getContext().getTypeAlignInChars(getContext().ShortTy); 1601 GV->setAlignment(Align.getQuantity()); 1602 } 1603 Fields[2] = llvm::ConstantExpr::getGetElementPtr(GV, Zeros, 2); 1604 1605 // String length. 1606 Ty = getTypes().ConvertType(getContext().LongTy); 1607 Fields[3] = llvm::ConstantInt::get(Ty, StringLength); 1608 1609 // The struct. 1610 C = llvm::ConstantStruct::get(STy, Fields); 1611 GV = new llvm::GlobalVariable(getModule(), C->getType(), true, 1612 llvm::GlobalVariable::PrivateLinkage, C, 1613 "_unnamed_cfstring_"); 1614 if (const char *Sect = getContext().Target.getCFStringSection()) 1615 GV->setSection(Sect); 1616 Entry.setValue(GV); 1617 1618 return GV; 1619} 1620 1621llvm::Constant * 1622CodeGenModule::GetAddrOfConstantString(const StringLiteral *Literal) { 1623 unsigned StringLength = 0; 1624 bool isUTF16 = false; 1625 llvm::StringMapEntry<llvm::Constant*> &Entry = 1626 GetConstantCFStringEntry(CFConstantStringMap, Literal, 1627 getTargetData().isLittleEndian(), 1628 isUTF16, StringLength); 1629 1630 if (llvm::Constant *C = Entry.getValue()) 1631 return C; 1632 1633 llvm::Constant *Zero = 1634 llvm::Constant::getNullValue(llvm::Type::getInt32Ty(VMContext)); 1635 llvm::Constant *Zeros[] = { Zero, Zero }; 1636 1637 // If we don't already have it, get _NSConstantStringClassReference. 1638 if (!ConstantStringClassRef) { 1639 std::string StringClass(getLangOptions().ObjCConstantStringClass); 1640 const llvm::Type *Ty = getTypes().ConvertType(getContext().IntTy); 1641 Ty = llvm::ArrayType::get(Ty, 0); 1642 llvm::Constant *GV; 1643 if (StringClass.empty()) 1644 GV = CreateRuntimeVariable(Ty, 1645 Features.ObjCNonFragileABI ? 1646 "OBJC_CLASS_$_NSConstantString" : 1647 "_NSConstantStringClassReference"); 1648 else { 1649 std::string str; 1650 if (Features.ObjCNonFragileABI) 1651 str = "OBJC_CLASS_$_" + StringClass; 1652 else 1653 str = "_" + StringClass + "ClassReference"; 1654 GV = CreateRuntimeVariable(Ty, str); 1655 } 1656 // Decay array -> ptr 1657 ConstantStringClassRef = 1658 llvm::ConstantExpr::getGetElementPtr(GV, Zeros, 2); 1659 } 1660 1661 QualType NSTy = getContext().getNSConstantStringType(); 1662 1663 const llvm::StructType *STy = 1664 cast<llvm::StructType>(getTypes().ConvertType(NSTy)); 1665 1666 std::vector<llvm::Constant*> Fields(3); 1667 1668 // Class pointer. 1669 Fields[0] = ConstantStringClassRef; 1670 1671 // String pointer. 1672 llvm::Constant *C = llvm::ConstantArray::get(VMContext, Entry.getKey().str()); 1673 1674 llvm::GlobalValue::LinkageTypes Linkage; 1675 bool isConstant; 1676 if (isUTF16) { 1677 // FIXME: why do utf strings get "_" labels instead of "L" labels? 1678 Linkage = llvm::GlobalValue::InternalLinkage; 1679 // Note: -fwritable-strings doesn't make unicode NSStrings writable, but 1680 // does make plain ascii ones writable. 1681 isConstant = true; 1682 } else { 1683 Linkage = llvm::GlobalValue::PrivateLinkage; 1684 isConstant = !Features.WritableStrings; 1685 } 1686 1687 llvm::GlobalVariable *GV = 1688 new llvm::GlobalVariable(getModule(), C->getType(), isConstant, Linkage, C, 1689 ".str"); 1690 GV->setUnnamedAddr(true); 1691 if (isUTF16) { 1692 CharUnits Align = getContext().getTypeAlignInChars(getContext().ShortTy); 1693 GV->setAlignment(Align.getQuantity()); 1694 } 1695 Fields[1] = llvm::ConstantExpr::getGetElementPtr(GV, Zeros, 2); 1696 1697 // String length. 1698 const llvm::Type *Ty = getTypes().ConvertType(getContext().UnsignedIntTy); 1699 Fields[2] = llvm::ConstantInt::get(Ty, StringLength); 1700 1701 // The struct. 1702 C = llvm::ConstantStruct::get(STy, Fields); 1703 GV = new llvm::GlobalVariable(getModule(), C->getType(), true, 1704 llvm::GlobalVariable::PrivateLinkage, C, 1705 "_unnamed_nsstring_"); 1706 // FIXME. Fix section. 1707 if (const char *Sect = 1708 Features.ObjCNonFragileABI 1709 ? getContext().Target.getNSStringNonFragileABISection() 1710 : getContext().Target.getNSStringSection()) 1711 GV->setSection(Sect); 1712 Entry.setValue(GV); 1713 1714 return GV; 1715} 1716 1717/// GetStringForStringLiteral - Return the appropriate bytes for a 1718/// string literal, properly padded to match the literal type. 1719std::string CodeGenModule::GetStringForStringLiteral(const StringLiteral *E) { 1720 const ConstantArrayType *CAT = 1721 getContext().getAsConstantArrayType(E->getType()); 1722 assert(CAT && "String isn't pointer or array!"); 1723 1724 // Resize the string to the right size. 1725 uint64_t RealLen = CAT->getSize().getZExtValue(); 1726 1727 if (E->isWide()) 1728 RealLen *= getContext().Target.getWCharWidth()/8; 1729 1730 std::string Str = E->getString().str(); 1731 Str.resize(RealLen, '\0'); 1732 1733 return Str; 1734} 1735 1736/// GetAddrOfConstantStringFromLiteral - Return a pointer to a 1737/// constant array for the given string literal. 1738llvm::Constant * 1739CodeGenModule::GetAddrOfConstantStringFromLiteral(const StringLiteral *S) { 1740 // FIXME: This can be more efficient. 1741 // FIXME: We shouldn't need to bitcast the constant in the wide string case. 1742 llvm::Constant *C = GetAddrOfConstantString(GetStringForStringLiteral(S)); 1743 if (S->isWide()) { 1744 llvm::Type *DestTy = 1745 llvm::PointerType::getUnqual(getTypes().ConvertType(S->getType())); 1746 C = llvm::ConstantExpr::getBitCast(C, DestTy); 1747 } 1748 return C; 1749} 1750 1751/// GetAddrOfConstantStringFromObjCEncode - Return a pointer to a constant 1752/// array for the given ObjCEncodeExpr node. 1753llvm::Constant * 1754CodeGenModule::GetAddrOfConstantStringFromObjCEncode(const ObjCEncodeExpr *E) { 1755 std::string Str; 1756 getContext().getObjCEncodingForType(E->getEncodedType(), Str); 1757 1758 return GetAddrOfConstantCString(Str); 1759} 1760 1761 1762/// GenerateWritableString -- Creates storage for a string literal. 1763static llvm::Constant *GenerateStringLiteral(const std::string &str, 1764 bool constant, 1765 CodeGenModule &CGM, 1766 const char *GlobalName) { 1767 // Create Constant for this string literal. Don't add a '\0'. 1768 llvm::Constant *C = 1769 llvm::ConstantArray::get(CGM.getLLVMContext(), str, false); 1770 1771 // Create a global variable for this string 1772 llvm::GlobalVariable *GV = 1773 new llvm::GlobalVariable(CGM.getModule(), C->getType(), constant, 1774 llvm::GlobalValue::PrivateLinkage, 1775 C, GlobalName); 1776 GV->setUnnamedAddr(true); 1777 return GV; 1778} 1779 1780/// GetAddrOfConstantString - Returns a pointer to a character array 1781/// containing the literal. This contents are exactly that of the 1782/// given string, i.e. it will not be null terminated automatically; 1783/// see GetAddrOfConstantCString. Note that whether the result is 1784/// actually a pointer to an LLVM constant depends on 1785/// Feature.WriteableStrings. 1786/// 1787/// The result has pointer to array type. 1788llvm::Constant *CodeGenModule::GetAddrOfConstantString(const std::string &str, 1789 const char *GlobalName) { 1790 bool IsConstant = !Features.WritableStrings; 1791 1792 // Get the default prefix if a name wasn't specified. 1793 if (!GlobalName) 1794 GlobalName = ".str"; 1795 1796 // Don't share any string literals if strings aren't constant. 1797 if (!IsConstant) 1798 return GenerateStringLiteral(str, false, *this, GlobalName); 1799 1800 llvm::StringMapEntry<llvm::Constant *> &Entry = 1801 ConstantStringMap.GetOrCreateValue(&str[0], &str[str.length()]); 1802 1803 if (Entry.getValue()) 1804 return Entry.getValue(); 1805 1806 // Create a global variable for this. 1807 llvm::Constant *C = GenerateStringLiteral(str, true, *this, GlobalName); 1808 Entry.setValue(C); 1809 return C; 1810} 1811 1812/// GetAddrOfConstantCString - Returns a pointer to a character 1813/// array containing the literal and a terminating '\-' 1814/// character. The result has pointer to array type. 1815llvm::Constant *CodeGenModule::GetAddrOfConstantCString(const std::string &str, 1816 const char *GlobalName){ 1817 return GetAddrOfConstantString(str + '\0', GlobalName); 1818} 1819 1820/// EmitObjCPropertyImplementations - Emit information for synthesized 1821/// properties for an implementation. 1822void CodeGenModule::EmitObjCPropertyImplementations(const 1823 ObjCImplementationDecl *D) { 1824 for (ObjCImplementationDecl::propimpl_iterator 1825 i = D->propimpl_begin(), e = D->propimpl_end(); i != e; ++i) { 1826 ObjCPropertyImplDecl *PID = *i; 1827 1828 // Dynamic is just for type-checking. 1829 if (PID->getPropertyImplementation() == ObjCPropertyImplDecl::Synthesize) { 1830 ObjCPropertyDecl *PD = PID->getPropertyDecl(); 1831 1832 // Determine which methods need to be implemented, some may have 1833 // been overridden. Note that ::isSynthesized is not the method 1834 // we want, that just indicates if the decl came from a 1835 // property. What we want to know is if the method is defined in 1836 // this implementation. 1837 if (!D->getInstanceMethod(PD->getGetterName())) 1838 CodeGenFunction(*this).GenerateObjCGetter( 1839 const_cast<ObjCImplementationDecl *>(D), PID); 1840 if (!PD->isReadOnly() && 1841 !D->getInstanceMethod(PD->getSetterName())) 1842 CodeGenFunction(*this).GenerateObjCSetter( 1843 const_cast<ObjCImplementationDecl *>(D), PID); 1844 } 1845 } 1846} 1847 1848/// EmitObjCIvarInitializations - Emit information for ivar initialization 1849/// for an implementation. 1850void CodeGenModule::EmitObjCIvarInitializations(ObjCImplementationDecl *D) { 1851 if (!Features.NeXTRuntime || D->getNumIvarInitializers() == 0) 1852 return; 1853 DeclContext* DC = const_cast<DeclContext*>(dyn_cast<DeclContext>(D)); 1854 assert(DC && "EmitObjCIvarInitializations - null DeclContext"); 1855 IdentifierInfo *II = &getContext().Idents.get(".cxx_destruct"); 1856 Selector cxxSelector = getContext().Selectors.getSelector(0, &II); 1857 ObjCMethodDecl *DTORMethod = ObjCMethodDecl::Create(getContext(), 1858 D->getLocation(), 1859 D->getLocation(), cxxSelector, 1860 getContext().VoidTy, 0, 1861 DC, true, false, true, false, 1862 ObjCMethodDecl::Required); 1863 D->addInstanceMethod(DTORMethod); 1864 CodeGenFunction(*this).GenerateObjCCtorDtorMethod(D, DTORMethod, false); 1865 1866 II = &getContext().Idents.get(".cxx_construct"); 1867 cxxSelector = getContext().Selectors.getSelector(0, &II); 1868 // The constructor returns 'self'. 1869 ObjCMethodDecl *CTORMethod = ObjCMethodDecl::Create(getContext(), 1870 D->getLocation(), 1871 D->getLocation(), cxxSelector, 1872 getContext().getObjCIdType(), 0, 1873 DC, true, false, true, false, 1874 ObjCMethodDecl::Required); 1875 D->addInstanceMethod(CTORMethod); 1876 CodeGenFunction(*this).GenerateObjCCtorDtorMethod(D, CTORMethod, true); 1877 1878 1879} 1880 1881/// EmitNamespace - Emit all declarations in a namespace. 1882void CodeGenModule::EmitNamespace(const NamespaceDecl *ND) { 1883 for (RecordDecl::decl_iterator I = ND->decls_begin(), E = ND->decls_end(); 1884 I != E; ++I) 1885 EmitTopLevelDecl(*I); 1886} 1887 1888// EmitLinkageSpec - Emit all declarations in a linkage spec. 1889void CodeGenModule::EmitLinkageSpec(const LinkageSpecDecl *LSD) { 1890 if (LSD->getLanguage() != LinkageSpecDecl::lang_c && 1891 LSD->getLanguage() != LinkageSpecDecl::lang_cxx) { 1892 ErrorUnsupported(LSD, "linkage spec"); 1893 return; 1894 } 1895 1896 for (RecordDecl::decl_iterator I = LSD->decls_begin(), E = LSD->decls_end(); 1897 I != E; ++I) 1898 EmitTopLevelDecl(*I); 1899} 1900 1901/// EmitTopLevelDecl - Emit code for a single top level declaration. 1902void CodeGenModule::EmitTopLevelDecl(Decl *D) { 1903 // If an error has occurred, stop code generation, but continue 1904 // parsing and semantic analysis (to ensure all warnings and errors 1905 // are emitted). 1906 if (Diags.hasErrorOccurred()) 1907 return; 1908 1909 // Ignore dependent declarations. 1910 if (D->getDeclContext() && D->getDeclContext()->isDependentContext()) 1911 return; 1912 1913 switch (D->getKind()) { 1914 case Decl::CXXConversion: 1915 case Decl::CXXMethod: 1916 case Decl::Function: 1917 // Skip function templates 1918 if (cast<FunctionDecl>(D)->getDescribedFunctionTemplate()) 1919 return; 1920 1921 EmitGlobal(cast<FunctionDecl>(D)); 1922 break; 1923 1924 case Decl::Var: 1925 EmitGlobal(cast<VarDecl>(D)); 1926 break; 1927 1928 // C++ Decls 1929 case Decl::Namespace: 1930 EmitNamespace(cast<NamespaceDecl>(D)); 1931 break; 1932 // No code generation needed. 1933 case Decl::UsingShadow: 1934 case Decl::Using: 1935 case Decl::UsingDirective: 1936 case Decl::ClassTemplate: 1937 case Decl::FunctionTemplate: 1938 case Decl::NamespaceAlias: 1939 break; 1940 case Decl::CXXConstructor: 1941 // Skip function templates 1942 if (cast<FunctionDecl>(D)->getDescribedFunctionTemplate()) 1943 return; 1944 1945 EmitCXXConstructors(cast<CXXConstructorDecl>(D)); 1946 break; 1947 case Decl::CXXDestructor: 1948 EmitCXXDestructors(cast<CXXDestructorDecl>(D)); 1949 break; 1950 1951 case Decl::StaticAssert: 1952 // Nothing to do. 1953 break; 1954 1955 // Objective-C Decls 1956 1957 // Forward declarations, no (immediate) code generation. 1958 case Decl::ObjCClass: 1959 case Decl::ObjCForwardProtocol: 1960 case Decl::ObjCInterface: 1961 break; 1962 1963 case Decl::ObjCCategory: { 1964 ObjCCategoryDecl *CD = cast<ObjCCategoryDecl>(D); 1965 if (CD->IsClassExtension() && CD->hasSynthBitfield()) 1966 Context.ResetObjCLayout(CD->getClassInterface()); 1967 break; 1968 } 1969 1970 1971 case Decl::ObjCProtocol: 1972 Runtime->GenerateProtocol(cast<ObjCProtocolDecl>(D)); 1973 break; 1974 1975 case Decl::ObjCCategoryImpl: 1976 // Categories have properties but don't support synthesize so we 1977 // can ignore them here. 1978 Runtime->GenerateCategory(cast<ObjCCategoryImplDecl>(D)); 1979 break; 1980 1981 case Decl::ObjCImplementation: { 1982 ObjCImplementationDecl *OMD = cast<ObjCImplementationDecl>(D); 1983 if (Features.ObjCNonFragileABI2 && OMD->hasSynthBitfield()) 1984 Context.ResetObjCLayout(OMD->getClassInterface()); 1985 EmitObjCPropertyImplementations(OMD); 1986 EmitObjCIvarInitializations(OMD); 1987 Runtime->GenerateClass(OMD); 1988 break; 1989 } 1990 case Decl::ObjCMethod: { 1991 ObjCMethodDecl *OMD = cast<ObjCMethodDecl>(D); 1992 // If this is not a prototype, emit the body. 1993 if (OMD->getBody()) 1994 CodeGenFunction(*this).GenerateObjCMethod(OMD); 1995 break; 1996 } 1997 case Decl::ObjCCompatibleAlias: 1998 // compatibility-alias is a directive and has no code gen. 1999 break; 2000 2001 case Decl::LinkageSpec: 2002 EmitLinkageSpec(cast<LinkageSpecDecl>(D)); 2003 break; 2004 2005 case Decl::FileScopeAsm: { 2006 FileScopeAsmDecl *AD = cast<FileScopeAsmDecl>(D); 2007 llvm::StringRef AsmString = AD->getAsmString()->getString(); 2008 2009 const std::string &S = getModule().getModuleInlineAsm(); 2010 if (S.empty()) 2011 getModule().setModuleInlineAsm(AsmString); 2012 else 2013 getModule().setModuleInlineAsm(S + '\n' + AsmString.str()); 2014 break; 2015 } 2016 2017 default: 2018 // Make sure we handled everything we should, every other kind is a 2019 // non-top-level decl. FIXME: Would be nice to have an isTopLevelDeclKind 2020 // function. Need to recode Decl::Kind to do that easily. 2021 assert(isa<TypeDecl>(D) && "Unsupported decl kind"); 2022 } 2023} 2024 2025/// Turns the given pointer into a constant. 2026static llvm::Constant *GetPointerConstant(llvm::LLVMContext &Context, 2027 const void *Ptr) { 2028 uintptr_t PtrInt = reinterpret_cast<uintptr_t>(Ptr); 2029 const llvm::Type *i64 = llvm::Type::getInt64Ty(Context); 2030 return llvm::ConstantInt::get(i64, PtrInt); 2031} 2032 2033static void EmitGlobalDeclMetadata(CodeGenModule &CGM, 2034 llvm::NamedMDNode *&GlobalMetadata, 2035 GlobalDecl D, 2036 llvm::GlobalValue *Addr) { 2037 if (!GlobalMetadata) 2038 GlobalMetadata = 2039 CGM.getModule().getOrInsertNamedMetadata("clang.global.decl.ptrs"); 2040 2041 // TODO: should we report variant information for ctors/dtors? 2042 llvm::Value *Ops[] = { 2043 Addr, 2044 GetPointerConstant(CGM.getLLVMContext(), D.getDecl()) 2045 }; 2046 GlobalMetadata->addOperand(llvm::MDNode::get(CGM.getLLVMContext(), Ops, 2)); 2047} 2048 2049/// Emits metadata nodes associating all the global values in the 2050/// current module with the Decls they came from. This is useful for 2051/// projects using IR gen as a subroutine. 2052/// 2053/// Since there's currently no way to associate an MDNode directly 2054/// with an llvm::GlobalValue, we create a global named metadata 2055/// with the name 'clang.global.decl.ptrs'. 2056void CodeGenModule::EmitDeclMetadata() { 2057 llvm::NamedMDNode *GlobalMetadata = 0; 2058 2059 // StaticLocalDeclMap 2060 for (llvm::DenseMap<GlobalDecl,llvm::StringRef>::iterator 2061 I = MangledDeclNames.begin(), E = MangledDeclNames.end(); 2062 I != E; ++I) { 2063 llvm::GlobalValue *Addr = getModule().getNamedValue(I->second); 2064 EmitGlobalDeclMetadata(*this, GlobalMetadata, I->first, Addr); 2065 } 2066} 2067 2068/// Emits metadata nodes for all the local variables in the current 2069/// function. 2070void CodeGenFunction::EmitDeclMetadata() { 2071 if (LocalDeclMap.empty()) return; 2072 2073 llvm::LLVMContext &Context = getLLVMContext(); 2074 2075 // Find the unique metadata ID for this name. 2076 unsigned DeclPtrKind = Context.getMDKindID("clang.decl.ptr"); 2077 2078 llvm::NamedMDNode *GlobalMetadata = 0; 2079 2080 for (llvm::DenseMap<const Decl*, llvm::Value*>::iterator 2081 I = LocalDeclMap.begin(), E = LocalDeclMap.end(); I != E; ++I) { 2082 const Decl *D = I->first; 2083 llvm::Value *Addr = I->second; 2084 2085 if (llvm::AllocaInst *Alloca = dyn_cast<llvm::AllocaInst>(Addr)) { 2086 llvm::Value *DAddr = GetPointerConstant(getLLVMContext(), D); 2087 Alloca->setMetadata(DeclPtrKind, llvm::MDNode::get(Context, &DAddr, 1)); 2088 } else if (llvm::GlobalValue *GV = dyn_cast<llvm::GlobalValue>(Addr)) { 2089 GlobalDecl GD = GlobalDecl(cast<VarDecl>(D)); 2090 EmitGlobalDeclMetadata(CGM, GlobalMetadata, GD, GV); 2091 } 2092 } 2093} 2094 2095///@name Custom Runtime Function Interfaces 2096///@{ 2097// 2098// FIXME: These can be eliminated once we can have clients just get the required 2099// AST nodes from the builtin tables. 2100 2101llvm::Constant *CodeGenModule::getBlockObjectDispose() { 2102 if (BlockObjectDispose) 2103 return BlockObjectDispose; 2104 2105 // If we saw an explicit decl, use that. 2106 if (BlockObjectDisposeDecl) { 2107 return BlockObjectDispose = GetAddrOfFunction( 2108 BlockObjectDisposeDecl, 2109 getTypes().GetFunctionType(BlockObjectDisposeDecl)); 2110 } 2111 2112 // Otherwise construct the function by hand. 2113 const llvm::FunctionType *FTy; 2114 std::vector<const llvm::Type*> ArgTys; 2115 const llvm::Type *ResultType = llvm::Type::getVoidTy(VMContext); 2116 ArgTys.push_back(PtrToInt8Ty); 2117 ArgTys.push_back(llvm::Type::getInt32Ty(VMContext)); 2118 FTy = llvm::FunctionType::get(ResultType, ArgTys, false); 2119 return BlockObjectDispose = 2120 CreateRuntimeFunction(FTy, "_Block_object_dispose"); 2121} 2122 2123llvm::Constant *CodeGenModule::getBlockObjectAssign() { 2124 if (BlockObjectAssign) 2125 return BlockObjectAssign; 2126 2127 // If we saw an explicit decl, use that. 2128 if (BlockObjectAssignDecl) { 2129 return BlockObjectAssign = GetAddrOfFunction( 2130 BlockObjectAssignDecl, 2131 getTypes().GetFunctionType(BlockObjectAssignDecl)); 2132 } 2133 2134 // Otherwise construct the function by hand. 2135 const llvm::FunctionType *FTy; 2136 std::vector<const llvm::Type*> ArgTys; 2137 const llvm::Type *ResultType = llvm::Type::getVoidTy(VMContext); 2138 ArgTys.push_back(PtrToInt8Ty); 2139 ArgTys.push_back(PtrToInt8Ty); 2140 ArgTys.push_back(llvm::Type::getInt32Ty(VMContext)); 2141 FTy = llvm::FunctionType::get(ResultType, ArgTys, false); 2142 return BlockObjectAssign = 2143 CreateRuntimeFunction(FTy, "_Block_object_assign"); 2144} 2145 2146llvm::Constant *CodeGenModule::getNSConcreteGlobalBlock() { 2147 if (NSConcreteGlobalBlock) 2148 return NSConcreteGlobalBlock; 2149 2150 // If we saw an explicit decl, use that. 2151 if (NSConcreteGlobalBlockDecl) { 2152 return NSConcreteGlobalBlock = GetAddrOfGlobalVar( 2153 NSConcreteGlobalBlockDecl, 2154 getTypes().ConvertType(NSConcreteGlobalBlockDecl->getType())); 2155 } 2156 2157 // Otherwise construct the variable by hand. 2158 return NSConcreteGlobalBlock = CreateRuntimeVariable( 2159 PtrToInt8Ty, "_NSConcreteGlobalBlock"); 2160} 2161 2162llvm::Constant *CodeGenModule::getNSConcreteStackBlock() { 2163 if (NSConcreteStackBlock) 2164 return NSConcreteStackBlock; 2165 2166 // If we saw an explicit decl, use that. 2167 if (NSConcreteStackBlockDecl) { 2168 return NSConcreteStackBlock = GetAddrOfGlobalVar( 2169 NSConcreteStackBlockDecl, 2170 getTypes().ConvertType(NSConcreteStackBlockDecl->getType())); 2171 } 2172 2173 // Otherwise construct the variable by hand. 2174 return NSConcreteStackBlock = CreateRuntimeVariable( 2175 PtrToInt8Ty, "_NSConcreteStackBlock"); 2176} 2177 2178///@} 2179