1 //===------- CGObjCGNU.cpp - Emit LLVM Code from ASTs for a Module --------===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 // 9 // This provides Objective-C code generation targeting the GNU runtime. The 10 // class in this file generates structures used by the GNU Objective-C runtime 11 // library. These structures are defined in objc/objc.h and objc/objc-api.h in 12 // the GNU runtime distribution. 13 // 14 //===----------------------------------------------------------------------===// 15 16 #include "CGCXXABI.h" 17 #include "CGCleanup.h" 18 #include "CGObjCRuntime.h" 19 #include "CodeGenFunction.h" 20 #include "CodeGenModule.h" 21 #include "clang/AST/ASTContext.h" 22 #include "clang/AST/Attr.h" 23 #include "clang/AST/Decl.h" 24 #include "clang/AST/DeclObjC.h" 25 #include "clang/AST/RecordLayout.h" 26 #include "clang/AST/StmtObjC.h" 27 #include "clang/Basic/FileManager.h" 28 #include "clang/Basic/SourceManager.h" 29 #include "clang/CodeGen/ConstantInitBuilder.h" 30 #include "llvm/ADT/SmallVector.h" 31 #include "llvm/ADT/StringMap.h" 32 #include "llvm/IR/DataLayout.h" 33 #include "llvm/IR/Intrinsics.h" 34 #include "llvm/IR/LLVMContext.h" 35 #include "llvm/IR/Module.h" 36 #include "llvm/Support/Compiler.h" 37 #include "llvm/Support/ConvertUTF.h" 38 #include <cctype> 39 40 using namespace clang; 41 using namespace CodeGen; 42 43 namespace { 44 45 /// Class that lazily initialises the runtime function. Avoids inserting the 46 /// types and the function declaration into a module if they're not used, and 47 /// avoids constructing the type more than once if it's used more than once. 48 class LazyRuntimeFunction { 49 CodeGenModule *CGM; 50 llvm::FunctionType *FTy; 51 const char *FunctionName; 52 llvm::FunctionCallee Function; 53 54 public: 55 /// Constructor leaves this class uninitialized, because it is intended to 56 /// be used as a field in another class and not all of the types that are 57 /// used as arguments will necessarily be available at construction time. 58 LazyRuntimeFunction() 59 : CGM(nullptr), FunctionName(nullptr), Function(nullptr) {} 60 61 /// Initialises the lazy function with the name, return type, and the types 62 /// of the arguments. 63 template <typename... Tys> 64 void init(CodeGenModule *Mod, const char *name, llvm::Type *RetTy, 65 Tys *... Types) { 66 CGM = Mod; 67 FunctionName = name; 68 Function = nullptr; 69 if(sizeof...(Tys)) { 70 SmallVector<llvm::Type *, 8> ArgTys({Types...}); 71 FTy = llvm::FunctionType::get(RetTy, ArgTys, false); 72 } 73 else { 74 FTy = llvm::FunctionType::get(RetTy, None, false); 75 } 76 } 77 78 llvm::FunctionType *getType() { return FTy; } 79 80 /// Overloaded cast operator, allows the class to be implicitly cast to an 81 /// LLVM constant. 82 operator llvm::FunctionCallee() { 83 if (!Function) { 84 if (!FunctionName) 85 return nullptr; 86 Function = CGM->CreateRuntimeFunction(FTy, FunctionName); 87 } 88 return Function; 89 } 90 }; 91 92 93 /// GNU Objective-C runtime code generation. This class implements the parts of 94 /// Objective-C support that are specific to the GNU family of runtimes (GCC, 95 /// GNUstep and ObjFW). 96 class CGObjCGNU : public CGObjCRuntime { 97 protected: 98 /// The LLVM module into which output is inserted 99 llvm::Module &TheModule; 100 /// strut objc_super. Used for sending messages to super. This structure 101 /// contains the receiver (object) and the expected class. 102 llvm::StructType *ObjCSuperTy; 103 /// struct objc_super*. The type of the argument to the superclass message 104 /// lookup functions. 105 llvm::PointerType *PtrToObjCSuperTy; 106 /// LLVM type for selectors. Opaque pointer (i8*) unless a header declaring 107 /// SEL is included in a header somewhere, in which case it will be whatever 108 /// type is declared in that header, most likely {i8*, i8*}. 109 llvm::PointerType *SelectorTy; 110 /// LLVM i8 type. Cached here to avoid repeatedly getting it in all of the 111 /// places where it's used 112 llvm::IntegerType *Int8Ty; 113 /// Pointer to i8 - LLVM type of char*, for all of the places where the 114 /// runtime needs to deal with C strings. 115 llvm::PointerType *PtrToInt8Ty; 116 /// struct objc_protocol type 117 llvm::StructType *ProtocolTy; 118 /// Protocol * type. 119 llvm::PointerType *ProtocolPtrTy; 120 /// Instance Method Pointer type. This is a pointer to a function that takes, 121 /// at a minimum, an object and a selector, and is the generic type for 122 /// Objective-C methods. Due to differences between variadic / non-variadic 123 /// calling conventions, it must always be cast to the correct type before 124 /// actually being used. 125 llvm::PointerType *IMPTy; 126 /// Type of an untyped Objective-C object. Clang treats id as a built-in type 127 /// when compiling Objective-C code, so this may be an opaque pointer (i8*), 128 /// but if the runtime header declaring it is included then it may be a 129 /// pointer to a structure. 130 llvm::PointerType *IdTy; 131 /// Pointer to a pointer to an Objective-C object. Used in the new ABI 132 /// message lookup function and some GC-related functions. 133 llvm::PointerType *PtrToIdTy; 134 /// The clang type of id. Used when using the clang CGCall infrastructure to 135 /// call Objective-C methods. 136 CanQualType ASTIdTy; 137 /// LLVM type for C int type. 138 llvm::IntegerType *IntTy; 139 /// LLVM type for an opaque pointer. This is identical to PtrToInt8Ty, but is 140 /// used in the code to document the difference between i8* meaning a pointer 141 /// to a C string and i8* meaning a pointer to some opaque type. 142 llvm::PointerType *PtrTy; 143 /// LLVM type for C long type. The runtime uses this in a lot of places where 144 /// it should be using intptr_t, but we can't fix this without breaking 145 /// compatibility with GCC... 146 llvm::IntegerType *LongTy; 147 /// LLVM type for C size_t. Used in various runtime data structures. 148 llvm::IntegerType *SizeTy; 149 /// LLVM type for C intptr_t. 150 llvm::IntegerType *IntPtrTy; 151 /// LLVM type for C ptrdiff_t. Mainly used in property accessor functions. 152 llvm::IntegerType *PtrDiffTy; 153 /// LLVM type for C int*. Used for GCC-ABI-compatible non-fragile instance 154 /// variables. 155 llvm::PointerType *PtrToIntTy; 156 /// LLVM type for Objective-C BOOL type. 157 llvm::Type *BoolTy; 158 /// 32-bit integer type, to save us needing to look it up every time it's used. 159 llvm::IntegerType *Int32Ty; 160 /// 64-bit integer type, to save us needing to look it up every time it's used. 161 llvm::IntegerType *Int64Ty; 162 /// The type of struct objc_property. 163 llvm::StructType *PropertyMetadataTy; 164 /// Metadata kind used to tie method lookups to message sends. The GNUstep 165 /// runtime provides some LLVM passes that can use this to do things like 166 /// automatic IMP caching and speculative inlining. 167 unsigned msgSendMDKind; 168 /// Does the current target use SEH-based exceptions? False implies 169 /// Itanium-style DWARF unwinding. 170 bool usesSEHExceptions; 171 172 /// Helper to check if we are targeting a specific runtime version or later. 173 bool isRuntime(ObjCRuntime::Kind kind, unsigned major, unsigned minor=0) { 174 const ObjCRuntime &R = CGM.getLangOpts().ObjCRuntime; 175 return (R.getKind() == kind) && 176 (R.getVersion() >= VersionTuple(major, minor)); 177 } 178 179 std::string ManglePublicSymbol(StringRef Name) { 180 return (StringRef(CGM.getTriple().isOSBinFormatCOFF() ? "$_" : "._") + Name).str(); 181 } 182 183 std::string SymbolForProtocol(Twine Name) { 184 return (ManglePublicSymbol("OBJC_PROTOCOL_") + Name).str(); 185 } 186 187 std::string SymbolForProtocolRef(StringRef Name) { 188 return (ManglePublicSymbol("OBJC_REF_PROTOCOL_") + Name).str(); 189 } 190 191 192 /// Helper function that generates a constant string and returns a pointer to 193 /// the start of the string. The result of this function can be used anywhere 194 /// where the C code specifies const char*. 195 llvm::Constant *MakeConstantString(StringRef Str, const char *Name = "") { 196 ConstantAddress Array = 197 CGM.GetAddrOfConstantCString(std::string(Str), Name); 198 return llvm::ConstantExpr::getGetElementPtr(Array.getElementType(), 199 Array.getPointer(), Zeros); 200 } 201 202 /// Emits a linkonce_odr string, whose name is the prefix followed by the 203 /// string value. This allows the linker to combine the strings between 204 /// different modules. Used for EH typeinfo names, selector strings, and a 205 /// few other things. 206 llvm::Constant *ExportUniqueString(const std::string &Str, 207 const std::string &prefix, 208 bool Private=false) { 209 std::string name = prefix + Str; 210 auto *ConstStr = TheModule.getGlobalVariable(name); 211 if (!ConstStr) { 212 llvm::Constant *value = llvm::ConstantDataArray::getString(VMContext,Str); 213 auto *GV = new llvm::GlobalVariable(TheModule, value->getType(), true, 214 llvm::GlobalValue::LinkOnceODRLinkage, value, name); 215 GV->setComdat(TheModule.getOrInsertComdat(name)); 216 if (Private) 217 GV->setVisibility(llvm::GlobalValue::HiddenVisibility); 218 ConstStr = GV; 219 } 220 return llvm::ConstantExpr::getGetElementPtr(ConstStr->getValueType(), 221 ConstStr, Zeros); 222 } 223 224 /// Returns a property name and encoding string. 225 llvm::Constant *MakePropertyEncodingString(const ObjCPropertyDecl *PD, 226 const Decl *Container) { 227 assert(!isRuntime(ObjCRuntime::GNUstep, 2)); 228 if (isRuntime(ObjCRuntime::GNUstep, 1, 6)) { 229 std::string NameAndAttributes; 230 std::string TypeStr = 231 CGM.getContext().getObjCEncodingForPropertyDecl(PD, Container); 232 NameAndAttributes += '\0'; 233 NameAndAttributes += TypeStr.length() + 3; 234 NameAndAttributes += TypeStr; 235 NameAndAttributes += '\0'; 236 NameAndAttributes += PD->getNameAsString(); 237 return MakeConstantString(NameAndAttributes); 238 } 239 return MakeConstantString(PD->getNameAsString()); 240 } 241 242 /// Push the property attributes into two structure fields. 243 void PushPropertyAttributes(ConstantStructBuilder &Fields, 244 const ObjCPropertyDecl *property, bool isSynthesized=true, bool 245 isDynamic=true) { 246 int attrs = property->getPropertyAttributes(); 247 // For read-only properties, clear the copy and retain flags 248 if (attrs & ObjCPropertyAttribute::kind_readonly) { 249 attrs &= ~ObjCPropertyAttribute::kind_copy; 250 attrs &= ~ObjCPropertyAttribute::kind_retain; 251 attrs &= ~ObjCPropertyAttribute::kind_weak; 252 attrs &= ~ObjCPropertyAttribute::kind_strong; 253 } 254 // The first flags field has the same attribute values as clang uses internally 255 Fields.addInt(Int8Ty, attrs & 0xff); 256 attrs >>= 8; 257 attrs <<= 2; 258 // For protocol properties, synthesized and dynamic have no meaning, so we 259 // reuse these flags to indicate that this is a protocol property (both set 260 // has no meaning, as a property can't be both synthesized and dynamic) 261 attrs |= isSynthesized ? (1<<0) : 0; 262 attrs |= isDynamic ? (1<<1) : 0; 263 // The second field is the next four fields left shifted by two, with the 264 // low bit set to indicate whether the field is synthesized or dynamic. 265 Fields.addInt(Int8Ty, attrs & 0xff); 266 // Two padding fields 267 Fields.addInt(Int8Ty, 0); 268 Fields.addInt(Int8Ty, 0); 269 } 270 271 virtual llvm::Constant *GenerateCategoryProtocolList(const 272 ObjCCategoryDecl *OCD); 273 virtual ConstantArrayBuilder PushPropertyListHeader(ConstantStructBuilder &Fields, 274 int count) { 275 // int count; 276 Fields.addInt(IntTy, count); 277 // int size; (only in GNUstep v2 ABI. 278 if (isRuntime(ObjCRuntime::GNUstep, 2)) { 279 llvm::DataLayout td(&TheModule); 280 Fields.addInt(IntTy, td.getTypeSizeInBits(PropertyMetadataTy) / 281 CGM.getContext().getCharWidth()); 282 } 283 // struct objc_property_list *next; 284 Fields.add(NULLPtr); 285 // struct objc_property properties[] 286 return Fields.beginArray(PropertyMetadataTy); 287 } 288 virtual void PushProperty(ConstantArrayBuilder &PropertiesArray, 289 const ObjCPropertyDecl *property, 290 const Decl *OCD, 291 bool isSynthesized=true, bool 292 isDynamic=true) { 293 auto Fields = PropertiesArray.beginStruct(PropertyMetadataTy); 294 ASTContext &Context = CGM.getContext(); 295 Fields.add(MakePropertyEncodingString(property, OCD)); 296 PushPropertyAttributes(Fields, property, isSynthesized, isDynamic); 297 auto addPropertyMethod = [&](const ObjCMethodDecl *accessor) { 298 if (accessor) { 299 std::string TypeStr = Context.getObjCEncodingForMethodDecl(accessor); 300 llvm::Constant *TypeEncoding = MakeConstantString(TypeStr); 301 Fields.add(MakeConstantString(accessor->getSelector().getAsString())); 302 Fields.add(TypeEncoding); 303 } else { 304 Fields.add(NULLPtr); 305 Fields.add(NULLPtr); 306 } 307 }; 308 addPropertyMethod(property->getGetterMethodDecl()); 309 addPropertyMethod(property->getSetterMethodDecl()); 310 Fields.finishAndAddTo(PropertiesArray); 311 } 312 313 /// Ensures that the value has the required type, by inserting a bitcast if 314 /// required. This function lets us avoid inserting bitcasts that are 315 /// redundant. 316 llvm::Value* EnforceType(CGBuilderTy &B, llvm::Value *V, llvm::Type *Ty) { 317 if (V->getType() == Ty) return V; 318 return B.CreateBitCast(V, Ty); 319 } 320 Address EnforceType(CGBuilderTy &B, Address V, llvm::Type *Ty) { 321 if (V.getType() == Ty) return V; 322 return B.CreateBitCast(V, Ty); 323 } 324 325 // Some zeros used for GEPs in lots of places. 326 llvm::Constant *Zeros[2]; 327 /// Null pointer value. Mainly used as a terminator in various arrays. 328 llvm::Constant *NULLPtr; 329 /// LLVM context. 330 llvm::LLVMContext &VMContext; 331 332 protected: 333 334 /// Placeholder for the class. Lots of things refer to the class before we've 335 /// actually emitted it. We use this alias as a placeholder, and then replace 336 /// it with a pointer to the class structure before finally emitting the 337 /// module. 338 llvm::GlobalAlias *ClassPtrAlias; 339 /// Placeholder for the metaclass. Lots of things refer to the class before 340 /// we've / actually emitted it. We use this alias as a placeholder, and then 341 /// replace / it with a pointer to the metaclass structure before finally 342 /// emitting the / module. 343 llvm::GlobalAlias *MetaClassPtrAlias; 344 /// All of the classes that have been generated for this compilation units. 345 std::vector<llvm::Constant*> Classes; 346 /// All of the categories that have been generated for this compilation units. 347 std::vector<llvm::Constant*> Categories; 348 /// All of the Objective-C constant strings that have been generated for this 349 /// compilation units. 350 std::vector<llvm::Constant*> ConstantStrings; 351 /// Map from string values to Objective-C constant strings in the output. 352 /// Used to prevent emitting Objective-C strings more than once. This should 353 /// not be required at all - CodeGenModule should manage this list. 354 llvm::StringMap<llvm::Constant*> ObjCStrings; 355 /// All of the protocols that have been declared. 356 llvm::StringMap<llvm::Constant*> ExistingProtocols; 357 /// For each variant of a selector, we store the type encoding and a 358 /// placeholder value. For an untyped selector, the type will be the empty 359 /// string. Selector references are all done via the module's selector table, 360 /// so we create an alias as a placeholder and then replace it with the real 361 /// value later. 362 typedef std::pair<std::string, llvm::GlobalAlias*> TypedSelector; 363 /// Type of the selector map. This is roughly equivalent to the structure 364 /// used in the GNUstep runtime, which maintains a list of all of the valid 365 /// types for a selector in a table. 366 typedef llvm::DenseMap<Selector, SmallVector<TypedSelector, 2> > 367 SelectorMap; 368 /// A map from selectors to selector types. This allows us to emit all 369 /// selectors of the same name and type together. 370 SelectorMap SelectorTable; 371 372 /// Selectors related to memory management. When compiling in GC mode, we 373 /// omit these. 374 Selector RetainSel, ReleaseSel, AutoreleaseSel; 375 /// Runtime functions used for memory management in GC mode. Note that clang 376 /// supports code generation for calling these functions, but neither GNU 377 /// runtime actually supports this API properly yet. 378 LazyRuntimeFunction IvarAssignFn, StrongCastAssignFn, MemMoveFn, WeakReadFn, 379 WeakAssignFn, GlobalAssignFn; 380 381 typedef std::pair<std::string, std::string> ClassAliasPair; 382 /// All classes that have aliases set for them. 383 std::vector<ClassAliasPair> ClassAliases; 384 385 protected: 386 /// Function used for throwing Objective-C exceptions. 387 LazyRuntimeFunction ExceptionThrowFn; 388 /// Function used for rethrowing exceptions, used at the end of \@finally or 389 /// \@synchronize blocks. 390 LazyRuntimeFunction ExceptionReThrowFn; 391 /// Function called when entering a catch function. This is required for 392 /// differentiating Objective-C exceptions and foreign exceptions. 393 LazyRuntimeFunction EnterCatchFn; 394 /// Function called when exiting from a catch block. Used to do exception 395 /// cleanup. 396 LazyRuntimeFunction ExitCatchFn; 397 /// Function called when entering an \@synchronize block. Acquires the lock. 398 LazyRuntimeFunction SyncEnterFn; 399 /// Function called when exiting an \@synchronize block. Releases the lock. 400 LazyRuntimeFunction SyncExitFn; 401 402 private: 403 /// Function called if fast enumeration detects that the collection is 404 /// modified during the update. 405 LazyRuntimeFunction EnumerationMutationFn; 406 /// Function for implementing synthesized property getters that return an 407 /// object. 408 LazyRuntimeFunction GetPropertyFn; 409 /// Function for implementing synthesized property setters that return an 410 /// object. 411 LazyRuntimeFunction SetPropertyFn; 412 /// Function used for non-object declared property getters. 413 LazyRuntimeFunction GetStructPropertyFn; 414 /// Function used for non-object declared property setters. 415 LazyRuntimeFunction SetStructPropertyFn; 416 417 protected: 418 /// The version of the runtime that this class targets. Must match the 419 /// version in the runtime. 420 int RuntimeVersion; 421 /// The version of the protocol class. Used to differentiate between ObjC1 422 /// and ObjC2 protocols. Objective-C 1 protocols can not contain optional 423 /// components and can not contain declared properties. We always emit 424 /// Objective-C 2 property structures, but we have to pretend that they're 425 /// Objective-C 1 property structures when targeting the GCC runtime or it 426 /// will abort. 427 const int ProtocolVersion; 428 /// The version of the class ABI. This value is used in the class structure 429 /// and indicates how various fields should be interpreted. 430 const int ClassABIVersion; 431 /// Generates an instance variable list structure. This is a structure 432 /// containing a size and an array of structures containing instance variable 433 /// metadata. This is used purely for introspection in the fragile ABI. In 434 /// the non-fragile ABI, it's used for instance variable fixup. 435 virtual llvm::Constant *GenerateIvarList(ArrayRef<llvm::Constant *> IvarNames, 436 ArrayRef<llvm::Constant *> IvarTypes, 437 ArrayRef<llvm::Constant *> IvarOffsets, 438 ArrayRef<llvm::Constant *> IvarAlign, 439 ArrayRef<Qualifiers::ObjCLifetime> IvarOwnership); 440 441 /// Generates a method list structure. This is a structure containing a size 442 /// and an array of structures containing method metadata. 443 /// 444 /// This structure is used by both classes and categories, and contains a next 445 /// pointer allowing them to be chained together in a linked list. 446 llvm::Constant *GenerateMethodList(StringRef ClassName, 447 StringRef CategoryName, 448 ArrayRef<const ObjCMethodDecl*> Methods, 449 bool isClassMethodList); 450 451 /// Emits an empty protocol. This is used for \@protocol() where no protocol 452 /// is found. The runtime will (hopefully) fix up the pointer to refer to the 453 /// real protocol. 454 virtual llvm::Constant *GenerateEmptyProtocol(StringRef ProtocolName); 455 456 /// Generates a list of property metadata structures. This follows the same 457 /// pattern as method and instance variable metadata lists. 458 llvm::Constant *GeneratePropertyList(const Decl *Container, 459 const ObjCContainerDecl *OCD, 460 bool isClassProperty=false, 461 bool protocolOptionalProperties=false); 462 463 /// Generates a list of referenced protocols. Classes, categories, and 464 /// protocols all use this structure. 465 llvm::Constant *GenerateProtocolList(ArrayRef<std::string> Protocols); 466 467 /// To ensure that all protocols are seen by the runtime, we add a category on 468 /// a class defined in the runtime, declaring no methods, but adopting the 469 /// protocols. This is a horribly ugly hack, but it allows us to collect all 470 /// of the protocols without changing the ABI. 471 void GenerateProtocolHolderCategory(); 472 473 /// Generates a class structure. 474 llvm::Constant *GenerateClassStructure( 475 llvm::Constant *MetaClass, 476 llvm::Constant *SuperClass, 477 unsigned info, 478 const char *Name, 479 llvm::Constant *Version, 480 llvm::Constant *InstanceSize, 481 llvm::Constant *IVars, 482 llvm::Constant *Methods, 483 llvm::Constant *Protocols, 484 llvm::Constant *IvarOffsets, 485 llvm::Constant *Properties, 486 llvm::Constant *StrongIvarBitmap, 487 llvm::Constant *WeakIvarBitmap, 488 bool isMeta=false); 489 490 /// Generates a method list. This is used by protocols to define the required 491 /// and optional methods. 492 virtual llvm::Constant *GenerateProtocolMethodList( 493 ArrayRef<const ObjCMethodDecl*> Methods); 494 /// Emits optional and required method lists. 495 template<class T> 496 void EmitProtocolMethodList(T &&Methods, llvm::Constant *&Required, 497 llvm::Constant *&Optional) { 498 SmallVector<const ObjCMethodDecl*, 16> RequiredMethods; 499 SmallVector<const ObjCMethodDecl*, 16> OptionalMethods; 500 for (const auto *I : Methods) 501 if (I->isOptional()) 502 OptionalMethods.push_back(I); 503 else 504 RequiredMethods.push_back(I); 505 Required = GenerateProtocolMethodList(RequiredMethods); 506 Optional = GenerateProtocolMethodList(OptionalMethods); 507 } 508 509 /// Returns a selector with the specified type encoding. An empty string is 510 /// used to return an untyped selector (with the types field set to NULL). 511 virtual llvm::Value *GetTypedSelector(CodeGenFunction &CGF, Selector Sel, 512 const std::string &TypeEncoding); 513 514 /// Returns the name of ivar offset variables. In the GNUstep v1 ABI, this 515 /// contains the class and ivar names, in the v2 ABI this contains the type 516 /// encoding as well. 517 virtual std::string GetIVarOffsetVariableName(const ObjCInterfaceDecl *ID, 518 const ObjCIvarDecl *Ivar) { 519 const std::string Name = "__objc_ivar_offset_" + ID->getNameAsString() 520 + '.' + Ivar->getNameAsString(); 521 return Name; 522 } 523 /// Returns the variable used to store the offset of an instance variable. 524 llvm::GlobalVariable *ObjCIvarOffsetVariable(const ObjCInterfaceDecl *ID, 525 const ObjCIvarDecl *Ivar); 526 /// Emits a reference to a class. This allows the linker to object if there 527 /// is no class of the matching name. 528 void EmitClassRef(const std::string &className); 529 530 /// Emits a pointer to the named class 531 virtual llvm::Value *GetClassNamed(CodeGenFunction &CGF, 532 const std::string &Name, bool isWeak); 533 534 /// Looks up the method for sending a message to the specified object. This 535 /// mechanism differs between the GCC and GNU runtimes, so this method must be 536 /// overridden in subclasses. 537 virtual llvm::Value *LookupIMP(CodeGenFunction &CGF, 538 llvm::Value *&Receiver, 539 llvm::Value *cmd, 540 llvm::MDNode *node, 541 MessageSendInfo &MSI) = 0; 542 543 /// Looks up the method for sending a message to a superclass. This 544 /// mechanism differs between the GCC and GNU runtimes, so this method must 545 /// be overridden in subclasses. 546 virtual llvm::Value *LookupIMPSuper(CodeGenFunction &CGF, 547 Address ObjCSuper, 548 llvm::Value *cmd, 549 MessageSendInfo &MSI) = 0; 550 551 /// Libobjc2 uses a bitfield representation where small(ish) bitfields are 552 /// stored in a 64-bit value with the low bit set to 1 and the remaining 63 553 /// bits set to their values, LSB first, while larger ones are stored in a 554 /// structure of this / form: 555 /// 556 /// struct { int32_t length; int32_t values[length]; }; 557 /// 558 /// The values in the array are stored in host-endian format, with the least 559 /// significant bit being assumed to come first in the bitfield. Therefore, 560 /// a bitfield with the 64th bit set will be (int64_t)&{ 2, [0, 1<<31] }, 561 /// while a bitfield / with the 63rd bit set will be 1<<64. 562 llvm::Constant *MakeBitField(ArrayRef<bool> bits); 563 564 public: 565 CGObjCGNU(CodeGenModule &cgm, unsigned runtimeABIVersion, 566 unsigned protocolClassVersion, unsigned classABI=1); 567 568 ConstantAddress GenerateConstantString(const StringLiteral *) override; 569 570 RValue 571 GenerateMessageSend(CodeGenFunction &CGF, ReturnValueSlot Return, 572 QualType ResultType, Selector Sel, 573 llvm::Value *Receiver, const CallArgList &CallArgs, 574 const ObjCInterfaceDecl *Class, 575 const ObjCMethodDecl *Method) override; 576 RValue 577 GenerateMessageSendSuper(CodeGenFunction &CGF, ReturnValueSlot Return, 578 QualType ResultType, Selector Sel, 579 const ObjCInterfaceDecl *Class, 580 bool isCategoryImpl, llvm::Value *Receiver, 581 bool IsClassMessage, const CallArgList &CallArgs, 582 const ObjCMethodDecl *Method) override; 583 llvm::Value *GetClass(CodeGenFunction &CGF, 584 const ObjCInterfaceDecl *OID) override; 585 llvm::Value *GetSelector(CodeGenFunction &CGF, Selector Sel) override; 586 Address GetAddrOfSelector(CodeGenFunction &CGF, Selector Sel) override; 587 llvm::Value *GetSelector(CodeGenFunction &CGF, 588 const ObjCMethodDecl *Method) override; 589 virtual llvm::Constant *GetConstantSelector(Selector Sel, 590 const std::string &TypeEncoding) { 591 llvm_unreachable("Runtime unable to generate constant selector"); 592 } 593 llvm::Constant *GetConstantSelector(const ObjCMethodDecl *M) { 594 return GetConstantSelector(M->getSelector(), 595 CGM.getContext().getObjCEncodingForMethodDecl(M)); 596 } 597 llvm::Constant *GetEHType(QualType T) override; 598 599 llvm::Function *GenerateMethod(const ObjCMethodDecl *OMD, 600 const ObjCContainerDecl *CD) override; 601 void GenerateDirectMethodPrologue(CodeGenFunction &CGF, llvm::Function *Fn, 602 const ObjCMethodDecl *OMD, 603 const ObjCContainerDecl *CD) override; 604 void GenerateCategory(const ObjCCategoryImplDecl *CMD) override; 605 void GenerateClass(const ObjCImplementationDecl *ClassDecl) override; 606 void RegisterAlias(const ObjCCompatibleAliasDecl *OAD) override; 607 llvm::Value *GenerateProtocolRef(CodeGenFunction &CGF, 608 const ObjCProtocolDecl *PD) override; 609 void GenerateProtocol(const ObjCProtocolDecl *PD) override; 610 611 virtual llvm::Constant *GenerateProtocolRef(const ObjCProtocolDecl *PD); 612 613 llvm::Constant *GetOrEmitProtocol(const ObjCProtocolDecl *PD) override { 614 return GenerateProtocolRef(PD); 615 } 616 617 llvm::Function *ModuleInitFunction() override; 618 llvm::FunctionCallee GetPropertyGetFunction() override; 619 llvm::FunctionCallee GetPropertySetFunction() override; 620 llvm::FunctionCallee GetOptimizedPropertySetFunction(bool atomic, 621 bool copy) override; 622 llvm::FunctionCallee GetSetStructFunction() override; 623 llvm::FunctionCallee GetGetStructFunction() override; 624 llvm::FunctionCallee GetCppAtomicObjectGetFunction() override; 625 llvm::FunctionCallee GetCppAtomicObjectSetFunction() override; 626 llvm::FunctionCallee EnumerationMutationFunction() override; 627 628 void EmitTryStmt(CodeGenFunction &CGF, 629 const ObjCAtTryStmt &S) override; 630 void EmitSynchronizedStmt(CodeGenFunction &CGF, 631 const ObjCAtSynchronizedStmt &S) override; 632 void EmitThrowStmt(CodeGenFunction &CGF, 633 const ObjCAtThrowStmt &S, 634 bool ClearInsertionPoint=true) override; 635 llvm::Value * EmitObjCWeakRead(CodeGenFunction &CGF, 636 Address AddrWeakObj) override; 637 void EmitObjCWeakAssign(CodeGenFunction &CGF, 638 llvm::Value *src, Address dst) override; 639 void EmitObjCGlobalAssign(CodeGenFunction &CGF, 640 llvm::Value *src, Address dest, 641 bool threadlocal=false) override; 642 void EmitObjCIvarAssign(CodeGenFunction &CGF, llvm::Value *src, 643 Address dest, llvm::Value *ivarOffset) override; 644 void EmitObjCStrongCastAssign(CodeGenFunction &CGF, 645 llvm::Value *src, Address dest) override; 646 void EmitGCMemmoveCollectable(CodeGenFunction &CGF, Address DestPtr, 647 Address SrcPtr, 648 llvm::Value *Size) override; 649 LValue EmitObjCValueForIvar(CodeGenFunction &CGF, QualType ObjectTy, 650 llvm::Value *BaseValue, const ObjCIvarDecl *Ivar, 651 unsigned CVRQualifiers) override; 652 llvm::Value *EmitIvarOffset(CodeGenFunction &CGF, 653 const ObjCInterfaceDecl *Interface, 654 const ObjCIvarDecl *Ivar) override; 655 llvm::Value *EmitNSAutoreleasePoolClassRef(CodeGenFunction &CGF) override; 656 llvm::Constant *BuildGCBlockLayout(CodeGenModule &CGM, 657 const CGBlockInfo &blockInfo) override { 658 return NULLPtr; 659 } 660 llvm::Constant *BuildRCBlockLayout(CodeGenModule &CGM, 661 const CGBlockInfo &blockInfo) override { 662 return NULLPtr; 663 } 664 665 llvm::Constant *BuildByrefLayout(CodeGenModule &CGM, QualType T) override { 666 return NULLPtr; 667 } 668 }; 669 670 /// Class representing the legacy GCC Objective-C ABI. This is the default when 671 /// -fobjc-nonfragile-abi is not specified. 672 /// 673 /// The GCC ABI target actually generates code that is approximately compatible 674 /// with the new GNUstep runtime ABI, but refrains from using any features that 675 /// would not work with the GCC runtime. For example, clang always generates 676 /// the extended form of the class structure, and the extra fields are simply 677 /// ignored by GCC libobjc. 678 class CGObjCGCC : public CGObjCGNU { 679 /// The GCC ABI message lookup function. Returns an IMP pointing to the 680 /// method implementation for this message. 681 LazyRuntimeFunction MsgLookupFn; 682 /// The GCC ABI superclass message lookup function. Takes a pointer to a 683 /// structure describing the receiver and the class, and a selector as 684 /// arguments. Returns the IMP for the corresponding method. 685 LazyRuntimeFunction MsgLookupSuperFn; 686 687 protected: 688 llvm::Value *LookupIMP(CodeGenFunction &CGF, llvm::Value *&Receiver, 689 llvm::Value *cmd, llvm::MDNode *node, 690 MessageSendInfo &MSI) override { 691 CGBuilderTy &Builder = CGF.Builder; 692 llvm::Value *args[] = { 693 EnforceType(Builder, Receiver, IdTy), 694 EnforceType(Builder, cmd, SelectorTy) }; 695 llvm::CallBase *imp = CGF.EmitRuntimeCallOrInvoke(MsgLookupFn, args); 696 imp->setMetadata(msgSendMDKind, node); 697 return imp; 698 } 699 700 llvm::Value *LookupIMPSuper(CodeGenFunction &CGF, Address ObjCSuper, 701 llvm::Value *cmd, MessageSendInfo &MSI) override { 702 CGBuilderTy &Builder = CGF.Builder; 703 llvm::Value *lookupArgs[] = {EnforceType(Builder, ObjCSuper, 704 PtrToObjCSuperTy).getPointer(), cmd}; 705 return CGF.EmitNounwindRuntimeCall(MsgLookupSuperFn, lookupArgs); 706 } 707 708 public: 709 CGObjCGCC(CodeGenModule &Mod) : CGObjCGNU(Mod, 8, 2) { 710 // IMP objc_msg_lookup(id, SEL); 711 MsgLookupFn.init(&CGM, "objc_msg_lookup", IMPTy, IdTy, SelectorTy); 712 // IMP objc_msg_lookup_super(struct objc_super*, SEL); 713 MsgLookupSuperFn.init(&CGM, "objc_msg_lookup_super", IMPTy, 714 PtrToObjCSuperTy, SelectorTy); 715 } 716 }; 717 718 /// Class used when targeting the new GNUstep runtime ABI. 719 class CGObjCGNUstep : public CGObjCGNU { 720 /// The slot lookup function. Returns a pointer to a cacheable structure 721 /// that contains (among other things) the IMP. 722 LazyRuntimeFunction SlotLookupFn; 723 /// The GNUstep ABI superclass message lookup function. Takes a pointer to 724 /// a structure describing the receiver and the class, and a selector as 725 /// arguments. Returns the slot for the corresponding method. Superclass 726 /// message lookup rarely changes, so this is a good caching opportunity. 727 LazyRuntimeFunction SlotLookupSuperFn; 728 /// Specialised function for setting atomic retain properties 729 LazyRuntimeFunction SetPropertyAtomic; 730 /// Specialised function for setting atomic copy properties 731 LazyRuntimeFunction SetPropertyAtomicCopy; 732 /// Specialised function for setting nonatomic retain properties 733 LazyRuntimeFunction SetPropertyNonAtomic; 734 /// Specialised function for setting nonatomic copy properties 735 LazyRuntimeFunction SetPropertyNonAtomicCopy; 736 /// Function to perform atomic copies of C++ objects with nontrivial copy 737 /// constructors from Objective-C ivars. 738 LazyRuntimeFunction CxxAtomicObjectGetFn; 739 /// Function to perform atomic copies of C++ objects with nontrivial copy 740 /// constructors to Objective-C ivars. 741 LazyRuntimeFunction CxxAtomicObjectSetFn; 742 /// Type of a slot structure pointer. This is returned by the various 743 /// lookup functions. 744 llvm::Type *SlotTy; 745 /// Type of a slot structure. 746 llvm::Type *SlotStructTy; 747 748 public: 749 llvm::Constant *GetEHType(QualType T) override; 750 751 protected: 752 llvm::Value *LookupIMP(CodeGenFunction &CGF, llvm::Value *&Receiver, 753 llvm::Value *cmd, llvm::MDNode *node, 754 MessageSendInfo &MSI) override { 755 CGBuilderTy &Builder = CGF.Builder; 756 llvm::FunctionCallee LookupFn = SlotLookupFn; 757 758 // Store the receiver on the stack so that we can reload it later 759 Address ReceiverPtr = 760 CGF.CreateTempAlloca(Receiver->getType(), CGF.getPointerAlign()); 761 Builder.CreateStore(Receiver, ReceiverPtr); 762 763 llvm::Value *self; 764 765 if (isa<ObjCMethodDecl>(CGF.CurCodeDecl)) { 766 self = CGF.LoadObjCSelf(); 767 } else { 768 self = llvm::ConstantPointerNull::get(IdTy); 769 } 770 771 // The lookup function is guaranteed not to capture the receiver pointer. 772 if (auto *LookupFn2 = dyn_cast<llvm::Function>(LookupFn.getCallee())) 773 LookupFn2->addParamAttr(0, llvm::Attribute::NoCapture); 774 775 llvm::Value *args[] = { 776 EnforceType(Builder, ReceiverPtr.getPointer(), PtrToIdTy), 777 EnforceType(Builder, cmd, SelectorTy), 778 EnforceType(Builder, self, IdTy) }; 779 llvm::CallBase *slot = CGF.EmitRuntimeCallOrInvoke(LookupFn, args); 780 slot->setOnlyReadsMemory(); 781 slot->setMetadata(msgSendMDKind, node); 782 783 // Load the imp from the slot 784 llvm::Value *imp = Builder.CreateAlignedLoad( 785 IMPTy, Builder.CreateStructGEP(SlotStructTy, slot, 4), 786 CGF.getPointerAlign()); 787 788 // The lookup function may have changed the receiver, so make sure we use 789 // the new one. 790 Receiver = Builder.CreateLoad(ReceiverPtr, true); 791 return imp; 792 } 793 794 llvm::Value *LookupIMPSuper(CodeGenFunction &CGF, Address ObjCSuper, 795 llvm::Value *cmd, 796 MessageSendInfo &MSI) override { 797 CGBuilderTy &Builder = CGF.Builder; 798 llvm::Value *lookupArgs[] = {ObjCSuper.getPointer(), cmd}; 799 800 llvm::CallInst *slot = 801 CGF.EmitNounwindRuntimeCall(SlotLookupSuperFn, lookupArgs); 802 slot->setOnlyReadsMemory(); 803 804 return Builder.CreateAlignedLoad( 805 IMPTy, Builder.CreateStructGEP(SlotStructTy, slot, 4), 806 CGF.getPointerAlign()); 807 } 808 809 public: 810 CGObjCGNUstep(CodeGenModule &Mod) : CGObjCGNUstep(Mod, 9, 3, 1) {} 811 CGObjCGNUstep(CodeGenModule &Mod, unsigned ABI, unsigned ProtocolABI, 812 unsigned ClassABI) : 813 CGObjCGNU(Mod, ABI, ProtocolABI, ClassABI) { 814 const ObjCRuntime &R = CGM.getLangOpts().ObjCRuntime; 815 816 SlotStructTy = llvm::StructType::get(PtrTy, PtrTy, PtrTy, IntTy, IMPTy); 817 SlotTy = llvm::PointerType::getUnqual(SlotStructTy); 818 // Slot_t objc_msg_lookup_sender(id *receiver, SEL selector, id sender); 819 SlotLookupFn.init(&CGM, "objc_msg_lookup_sender", SlotTy, PtrToIdTy, 820 SelectorTy, IdTy); 821 // Slot_t objc_slot_lookup_super(struct objc_super*, SEL); 822 SlotLookupSuperFn.init(&CGM, "objc_slot_lookup_super", SlotTy, 823 PtrToObjCSuperTy, SelectorTy); 824 // If we're in ObjC++ mode, then we want to make 825 if (usesSEHExceptions) { 826 llvm::Type *VoidTy = llvm::Type::getVoidTy(VMContext); 827 // void objc_exception_rethrow(void) 828 ExceptionReThrowFn.init(&CGM, "objc_exception_rethrow", VoidTy); 829 } else if (CGM.getLangOpts().CPlusPlus) { 830 llvm::Type *VoidTy = llvm::Type::getVoidTy(VMContext); 831 // void *__cxa_begin_catch(void *e) 832 EnterCatchFn.init(&CGM, "__cxa_begin_catch", PtrTy, PtrTy); 833 // void __cxa_end_catch(void) 834 ExitCatchFn.init(&CGM, "__cxa_end_catch", VoidTy); 835 // void _Unwind_Resume_or_Rethrow(void*) 836 ExceptionReThrowFn.init(&CGM, "_Unwind_Resume_or_Rethrow", VoidTy, 837 PtrTy); 838 } else if (R.getVersion() >= VersionTuple(1, 7)) { 839 llvm::Type *VoidTy = llvm::Type::getVoidTy(VMContext); 840 // id objc_begin_catch(void *e) 841 EnterCatchFn.init(&CGM, "objc_begin_catch", IdTy, PtrTy); 842 // void objc_end_catch(void) 843 ExitCatchFn.init(&CGM, "objc_end_catch", VoidTy); 844 // void _Unwind_Resume_or_Rethrow(void*) 845 ExceptionReThrowFn.init(&CGM, "objc_exception_rethrow", VoidTy, PtrTy); 846 } 847 llvm::Type *VoidTy = llvm::Type::getVoidTy(VMContext); 848 SetPropertyAtomic.init(&CGM, "objc_setProperty_atomic", VoidTy, IdTy, 849 SelectorTy, IdTy, PtrDiffTy); 850 SetPropertyAtomicCopy.init(&CGM, "objc_setProperty_atomic_copy", VoidTy, 851 IdTy, SelectorTy, IdTy, PtrDiffTy); 852 SetPropertyNonAtomic.init(&CGM, "objc_setProperty_nonatomic", VoidTy, 853 IdTy, SelectorTy, IdTy, PtrDiffTy); 854 SetPropertyNonAtomicCopy.init(&CGM, "objc_setProperty_nonatomic_copy", 855 VoidTy, IdTy, SelectorTy, IdTy, PtrDiffTy); 856 // void objc_setCppObjectAtomic(void *dest, const void *src, void 857 // *helper); 858 CxxAtomicObjectSetFn.init(&CGM, "objc_setCppObjectAtomic", VoidTy, PtrTy, 859 PtrTy, PtrTy); 860 // void objc_getCppObjectAtomic(void *dest, const void *src, void 861 // *helper); 862 CxxAtomicObjectGetFn.init(&CGM, "objc_getCppObjectAtomic", VoidTy, PtrTy, 863 PtrTy, PtrTy); 864 } 865 866 llvm::FunctionCallee GetCppAtomicObjectGetFunction() override { 867 // The optimised functions were added in version 1.7 of the GNUstep 868 // runtime. 869 assert (CGM.getLangOpts().ObjCRuntime.getVersion() >= 870 VersionTuple(1, 7)); 871 return CxxAtomicObjectGetFn; 872 } 873 874 llvm::FunctionCallee GetCppAtomicObjectSetFunction() override { 875 // The optimised functions were added in version 1.7 of the GNUstep 876 // runtime. 877 assert (CGM.getLangOpts().ObjCRuntime.getVersion() >= 878 VersionTuple(1, 7)); 879 return CxxAtomicObjectSetFn; 880 } 881 882 llvm::FunctionCallee GetOptimizedPropertySetFunction(bool atomic, 883 bool copy) override { 884 // The optimised property functions omit the GC check, and so are not 885 // safe to use in GC mode. The standard functions are fast in GC mode, 886 // so there is less advantage in using them. 887 assert ((CGM.getLangOpts().getGC() == LangOptions::NonGC)); 888 // The optimised functions were added in version 1.7 of the GNUstep 889 // runtime. 890 assert (CGM.getLangOpts().ObjCRuntime.getVersion() >= 891 VersionTuple(1, 7)); 892 893 if (atomic) { 894 if (copy) return SetPropertyAtomicCopy; 895 return SetPropertyAtomic; 896 } 897 898 return copy ? SetPropertyNonAtomicCopy : SetPropertyNonAtomic; 899 } 900 }; 901 902 /// GNUstep Objective-C ABI version 2 implementation. 903 /// This is the ABI that provides a clean break with the legacy GCC ABI and 904 /// cleans up a number of things that were added to work around 1980s linkers. 905 class CGObjCGNUstep2 : public CGObjCGNUstep { 906 enum SectionKind 907 { 908 SelectorSection = 0, 909 ClassSection, 910 ClassReferenceSection, 911 CategorySection, 912 ProtocolSection, 913 ProtocolReferenceSection, 914 ClassAliasSection, 915 ConstantStringSection 916 }; 917 static const char *const SectionsBaseNames[8]; 918 static const char *const PECOFFSectionsBaseNames[8]; 919 template<SectionKind K> 920 std::string sectionName() { 921 if (CGM.getTriple().isOSBinFormatCOFF()) { 922 std::string name(PECOFFSectionsBaseNames[K]); 923 name += "$m"; 924 return name; 925 } 926 return SectionsBaseNames[K]; 927 } 928 /// The GCC ABI superclass message lookup function. Takes a pointer to a 929 /// structure describing the receiver and the class, and a selector as 930 /// arguments. Returns the IMP for the corresponding method. 931 LazyRuntimeFunction MsgLookupSuperFn; 932 /// A flag indicating if we've emitted at least one protocol. 933 /// If we haven't, then we need to emit an empty protocol, to ensure that the 934 /// __start__objc_protocols and __stop__objc_protocols sections exist. 935 bool EmittedProtocol = false; 936 /// A flag indicating if we've emitted at least one protocol reference. 937 /// If we haven't, then we need to emit an empty protocol, to ensure that the 938 /// __start__objc_protocol_refs and __stop__objc_protocol_refs sections 939 /// exist. 940 bool EmittedProtocolRef = false; 941 /// A flag indicating if we've emitted at least one class. 942 /// If we haven't, then we need to emit an empty protocol, to ensure that the 943 /// __start__objc_classes and __stop__objc_classes sections / exist. 944 bool EmittedClass = false; 945 /// Generate the name of a symbol for a reference to a class. Accesses to 946 /// classes should be indirected via this. 947 948 typedef std::pair<std::string, std::pair<llvm::GlobalVariable*, int>> 949 EarlyInitPair; 950 std::vector<EarlyInitPair> EarlyInitList; 951 952 std::string SymbolForClassRef(StringRef Name, bool isWeak) { 953 if (isWeak) 954 return (ManglePublicSymbol("OBJC_WEAK_REF_CLASS_") + Name).str(); 955 else 956 return (ManglePublicSymbol("OBJC_REF_CLASS_") + Name).str(); 957 } 958 /// Generate the name of a class symbol. 959 std::string SymbolForClass(StringRef Name) { 960 return (ManglePublicSymbol("OBJC_CLASS_") + Name).str(); 961 } 962 void CallRuntimeFunction(CGBuilderTy &B, StringRef FunctionName, 963 ArrayRef<llvm::Value*> Args) { 964 SmallVector<llvm::Type *,8> Types; 965 for (auto *Arg : Args) 966 Types.push_back(Arg->getType()); 967 llvm::FunctionType *FT = llvm::FunctionType::get(B.getVoidTy(), Types, 968 false); 969 llvm::FunctionCallee Fn = CGM.CreateRuntimeFunction(FT, FunctionName); 970 B.CreateCall(Fn, Args); 971 } 972 973 ConstantAddress GenerateConstantString(const StringLiteral *SL) override { 974 975 auto Str = SL->getString(); 976 CharUnits Align = CGM.getPointerAlign(); 977 978 // Look for an existing one 979 llvm::StringMap<llvm::Constant*>::iterator old = ObjCStrings.find(Str); 980 if (old != ObjCStrings.end()) 981 return ConstantAddress(old->getValue(), Align); 982 983 bool isNonASCII = SL->containsNonAscii(); 984 985 auto LiteralLength = SL->getLength(); 986 987 if ((CGM.getTarget().getPointerWidth(0) == 64) && 988 (LiteralLength < 9) && !isNonASCII) { 989 // Tiny strings are only used on 64-bit platforms. They store 8 7-bit 990 // ASCII characters in the high 56 bits, followed by a 4-bit length and a 991 // 3-bit tag (which is always 4). 992 uint64_t str = 0; 993 // Fill in the characters 994 for (unsigned i=0 ; i<LiteralLength ; i++) 995 str |= ((uint64_t)SL->getCodeUnit(i)) << ((64 - 4 - 3) - (i*7)); 996 // Fill in the length 997 str |= LiteralLength << 3; 998 // Set the tag 999 str |= 4; 1000 auto *ObjCStr = llvm::ConstantExpr::getIntToPtr( 1001 llvm::ConstantInt::get(Int64Ty, str), IdTy); 1002 ObjCStrings[Str] = ObjCStr; 1003 return ConstantAddress(ObjCStr, Align); 1004 } 1005 1006 StringRef StringClass = CGM.getLangOpts().ObjCConstantStringClass; 1007 1008 if (StringClass.empty()) StringClass = "NSConstantString"; 1009 1010 std::string Sym = SymbolForClass(StringClass); 1011 1012 llvm::Constant *isa = TheModule.getNamedGlobal(Sym); 1013 1014 if (!isa) { 1015 isa = new llvm::GlobalVariable(TheModule, IdTy, /* isConstant */false, 1016 llvm::GlobalValue::ExternalLinkage, nullptr, Sym); 1017 if (CGM.getTriple().isOSBinFormatCOFF()) { 1018 cast<llvm::GlobalValue>(isa)->setDLLStorageClass(llvm::GlobalValue::DLLImportStorageClass); 1019 } 1020 } else if (isa->getType() != PtrToIdTy) 1021 isa = llvm::ConstantExpr::getBitCast(isa, PtrToIdTy); 1022 1023 // struct 1024 // { 1025 // Class isa; 1026 // uint32_t flags; 1027 // uint32_t length; // Number of codepoints 1028 // uint32_t size; // Number of bytes 1029 // uint32_t hash; 1030 // const char *data; 1031 // }; 1032 1033 ConstantInitBuilder Builder(CGM); 1034 auto Fields = Builder.beginStruct(); 1035 if (!CGM.getTriple().isOSBinFormatCOFF()) { 1036 Fields.add(isa); 1037 } else { 1038 Fields.addNullPointer(PtrTy); 1039 } 1040 // For now, all non-ASCII strings are represented as UTF-16. As such, the 1041 // number of bytes is simply double the number of UTF-16 codepoints. In 1042 // ASCII strings, the number of bytes is equal to the number of non-ASCII 1043 // codepoints. 1044 if (isNonASCII) { 1045 unsigned NumU8CodeUnits = Str.size(); 1046 // A UTF-16 representation of a unicode string contains at most the same 1047 // number of code units as a UTF-8 representation. Allocate that much 1048 // space, plus one for the final null character. 1049 SmallVector<llvm::UTF16, 128> ToBuf(NumU8CodeUnits + 1); 1050 const llvm::UTF8 *FromPtr = (const llvm::UTF8 *)Str.data(); 1051 llvm::UTF16 *ToPtr = &ToBuf[0]; 1052 (void)llvm::ConvertUTF8toUTF16(&FromPtr, FromPtr + NumU8CodeUnits, 1053 &ToPtr, ToPtr + NumU8CodeUnits, llvm::strictConversion); 1054 uint32_t StringLength = ToPtr - &ToBuf[0]; 1055 // Add null terminator 1056 *ToPtr = 0; 1057 // Flags: 2 indicates UTF-16 encoding 1058 Fields.addInt(Int32Ty, 2); 1059 // Number of UTF-16 codepoints 1060 Fields.addInt(Int32Ty, StringLength); 1061 // Number of bytes 1062 Fields.addInt(Int32Ty, StringLength * 2); 1063 // Hash. Not currently initialised by the compiler. 1064 Fields.addInt(Int32Ty, 0); 1065 // pointer to the data string. 1066 auto Arr = llvm::makeArrayRef(&ToBuf[0], ToPtr+1); 1067 auto *C = llvm::ConstantDataArray::get(VMContext, Arr); 1068 auto *Buffer = new llvm::GlobalVariable(TheModule, C->getType(), 1069 /*isConstant=*/true, llvm::GlobalValue::PrivateLinkage, C, ".str"); 1070 Buffer->setUnnamedAddr(llvm::GlobalValue::UnnamedAddr::Global); 1071 Fields.add(Buffer); 1072 } else { 1073 // Flags: 0 indicates ASCII encoding 1074 Fields.addInt(Int32Ty, 0); 1075 // Number of UTF-16 codepoints, each ASCII byte is a UTF-16 codepoint 1076 Fields.addInt(Int32Ty, Str.size()); 1077 // Number of bytes 1078 Fields.addInt(Int32Ty, Str.size()); 1079 // Hash. Not currently initialised by the compiler. 1080 Fields.addInt(Int32Ty, 0); 1081 // Data pointer 1082 Fields.add(MakeConstantString(Str)); 1083 } 1084 std::string StringName; 1085 bool isNamed = !isNonASCII; 1086 if (isNamed) { 1087 StringName = ".objc_str_"; 1088 for (int i=0,e=Str.size() ; i<e ; ++i) { 1089 unsigned char c = Str[i]; 1090 if (isalnum(c)) 1091 StringName += c; 1092 else if (c == ' ') 1093 StringName += '_'; 1094 else { 1095 isNamed = false; 1096 break; 1097 } 1098 } 1099 } 1100 llvm::GlobalVariable *ObjCStrGV = 1101 Fields.finishAndCreateGlobal( 1102 isNamed ? StringRef(StringName) : ".objc_string", 1103 Align, false, isNamed ? llvm::GlobalValue::LinkOnceODRLinkage 1104 : llvm::GlobalValue::PrivateLinkage); 1105 ObjCStrGV->setSection(sectionName<ConstantStringSection>()); 1106 if (isNamed) { 1107 ObjCStrGV->setComdat(TheModule.getOrInsertComdat(StringName)); 1108 ObjCStrGV->setVisibility(llvm::GlobalValue::HiddenVisibility); 1109 } 1110 if (CGM.getTriple().isOSBinFormatCOFF()) { 1111 std::pair<llvm::GlobalVariable*, int> v{ObjCStrGV, 0}; 1112 EarlyInitList.emplace_back(Sym, v); 1113 } 1114 llvm::Constant *ObjCStr = llvm::ConstantExpr::getBitCast(ObjCStrGV, IdTy); 1115 ObjCStrings[Str] = ObjCStr; 1116 ConstantStrings.push_back(ObjCStr); 1117 return ConstantAddress(ObjCStr, Align); 1118 } 1119 1120 void PushProperty(ConstantArrayBuilder &PropertiesArray, 1121 const ObjCPropertyDecl *property, 1122 const Decl *OCD, 1123 bool isSynthesized=true, bool 1124 isDynamic=true) override { 1125 // struct objc_property 1126 // { 1127 // const char *name; 1128 // const char *attributes; 1129 // const char *type; 1130 // SEL getter; 1131 // SEL setter; 1132 // }; 1133 auto Fields = PropertiesArray.beginStruct(PropertyMetadataTy); 1134 ASTContext &Context = CGM.getContext(); 1135 Fields.add(MakeConstantString(property->getNameAsString())); 1136 std::string TypeStr = 1137 CGM.getContext().getObjCEncodingForPropertyDecl(property, OCD); 1138 Fields.add(MakeConstantString(TypeStr)); 1139 std::string typeStr; 1140 Context.getObjCEncodingForType(property->getType(), typeStr); 1141 Fields.add(MakeConstantString(typeStr)); 1142 auto addPropertyMethod = [&](const ObjCMethodDecl *accessor) { 1143 if (accessor) { 1144 std::string TypeStr = Context.getObjCEncodingForMethodDecl(accessor); 1145 Fields.add(GetConstantSelector(accessor->getSelector(), TypeStr)); 1146 } else { 1147 Fields.add(NULLPtr); 1148 } 1149 }; 1150 addPropertyMethod(property->getGetterMethodDecl()); 1151 addPropertyMethod(property->getSetterMethodDecl()); 1152 Fields.finishAndAddTo(PropertiesArray); 1153 } 1154 1155 llvm::Constant * 1156 GenerateProtocolMethodList(ArrayRef<const ObjCMethodDecl*> Methods) override { 1157 // struct objc_protocol_method_description 1158 // { 1159 // SEL selector; 1160 // const char *types; 1161 // }; 1162 llvm::StructType *ObjCMethodDescTy = 1163 llvm::StructType::get(CGM.getLLVMContext(), 1164 { PtrToInt8Ty, PtrToInt8Ty }); 1165 ASTContext &Context = CGM.getContext(); 1166 ConstantInitBuilder Builder(CGM); 1167 // struct objc_protocol_method_description_list 1168 // { 1169 // int count; 1170 // int size; 1171 // struct objc_protocol_method_description methods[]; 1172 // }; 1173 auto MethodList = Builder.beginStruct(); 1174 // int count; 1175 MethodList.addInt(IntTy, Methods.size()); 1176 // int size; // sizeof(struct objc_method_description) 1177 llvm::DataLayout td(&TheModule); 1178 MethodList.addInt(IntTy, td.getTypeSizeInBits(ObjCMethodDescTy) / 1179 CGM.getContext().getCharWidth()); 1180 // struct objc_method_description[] 1181 auto MethodArray = MethodList.beginArray(ObjCMethodDescTy); 1182 for (auto *M : Methods) { 1183 auto Method = MethodArray.beginStruct(ObjCMethodDescTy); 1184 Method.add(CGObjCGNU::GetConstantSelector(M)); 1185 Method.add(GetTypeString(Context.getObjCEncodingForMethodDecl(M, true))); 1186 Method.finishAndAddTo(MethodArray); 1187 } 1188 MethodArray.finishAndAddTo(MethodList); 1189 return MethodList.finishAndCreateGlobal(".objc_protocol_method_list", 1190 CGM.getPointerAlign()); 1191 } 1192 llvm::Constant *GenerateCategoryProtocolList(const ObjCCategoryDecl *OCD) 1193 override { 1194 const auto &ReferencedProtocols = OCD->getReferencedProtocols(); 1195 auto RuntimeProtocols = GetRuntimeProtocolList(ReferencedProtocols.begin(), 1196 ReferencedProtocols.end()); 1197 SmallVector<llvm::Constant *, 16> Protocols; 1198 for (const auto *PI : RuntimeProtocols) 1199 Protocols.push_back( 1200 llvm::ConstantExpr::getBitCast(GenerateProtocolRef(PI), 1201 ProtocolPtrTy)); 1202 return GenerateProtocolList(Protocols); 1203 } 1204 1205 llvm::Value *LookupIMPSuper(CodeGenFunction &CGF, Address ObjCSuper, 1206 llvm::Value *cmd, MessageSendInfo &MSI) override { 1207 // Don't access the slot unless we're trying to cache the result. 1208 CGBuilderTy &Builder = CGF.Builder; 1209 llvm::Value *lookupArgs[] = {CGObjCGNU::EnforceType(Builder, ObjCSuper, 1210 PtrToObjCSuperTy).getPointer(), cmd}; 1211 return CGF.EmitNounwindRuntimeCall(MsgLookupSuperFn, lookupArgs); 1212 } 1213 1214 llvm::GlobalVariable *GetClassVar(StringRef Name, bool isWeak=false) { 1215 std::string SymbolName = SymbolForClassRef(Name, isWeak); 1216 auto *ClassSymbol = TheModule.getNamedGlobal(SymbolName); 1217 if (ClassSymbol) 1218 return ClassSymbol; 1219 ClassSymbol = new llvm::GlobalVariable(TheModule, 1220 IdTy, false, llvm::GlobalValue::ExternalLinkage, 1221 nullptr, SymbolName); 1222 // If this is a weak symbol, then we are creating a valid definition for 1223 // the symbol, pointing to a weak definition of the real class pointer. If 1224 // this is not a weak reference, then we are expecting another compilation 1225 // unit to provide the real indirection symbol. 1226 if (isWeak) 1227 ClassSymbol->setInitializer(new llvm::GlobalVariable(TheModule, 1228 Int8Ty, false, llvm::GlobalValue::ExternalWeakLinkage, 1229 nullptr, SymbolForClass(Name))); 1230 else { 1231 if (CGM.getTriple().isOSBinFormatCOFF()) { 1232 IdentifierInfo &II = CGM.getContext().Idents.get(Name); 1233 TranslationUnitDecl *TUDecl = CGM.getContext().getTranslationUnitDecl(); 1234 DeclContext *DC = TranslationUnitDecl::castToDeclContext(TUDecl); 1235 1236 const ObjCInterfaceDecl *OID = nullptr; 1237 for (const auto *Result : DC->lookup(&II)) 1238 if ((OID = dyn_cast<ObjCInterfaceDecl>(Result))) 1239 break; 1240 1241 // The first Interface we find may be a @class, 1242 // which should only be treated as the source of 1243 // truth in the absence of a true declaration. 1244 assert(OID && "Failed to find ObjCInterfaceDecl"); 1245 const ObjCInterfaceDecl *OIDDef = OID->getDefinition(); 1246 if (OIDDef != nullptr) 1247 OID = OIDDef; 1248 1249 auto Storage = llvm::GlobalValue::DefaultStorageClass; 1250 if (OID->hasAttr<DLLImportAttr>()) 1251 Storage = llvm::GlobalValue::DLLImportStorageClass; 1252 else if (OID->hasAttr<DLLExportAttr>()) 1253 Storage = llvm::GlobalValue::DLLExportStorageClass; 1254 1255 cast<llvm::GlobalValue>(ClassSymbol)->setDLLStorageClass(Storage); 1256 } 1257 } 1258 assert(ClassSymbol->getName() == SymbolName); 1259 return ClassSymbol; 1260 } 1261 llvm::Value *GetClassNamed(CodeGenFunction &CGF, 1262 const std::string &Name, 1263 bool isWeak) override { 1264 return CGF.Builder.CreateLoad(Address(GetClassVar(Name, isWeak), 1265 CGM.getPointerAlign())); 1266 } 1267 int32_t FlagsForOwnership(Qualifiers::ObjCLifetime Ownership) { 1268 // typedef enum { 1269 // ownership_invalid = 0, 1270 // ownership_strong = 1, 1271 // ownership_weak = 2, 1272 // ownership_unsafe = 3 1273 // } ivar_ownership; 1274 int Flag; 1275 switch (Ownership) { 1276 case Qualifiers::OCL_Strong: 1277 Flag = 1; 1278 break; 1279 case Qualifiers::OCL_Weak: 1280 Flag = 2; 1281 break; 1282 case Qualifiers::OCL_ExplicitNone: 1283 Flag = 3; 1284 break; 1285 case Qualifiers::OCL_None: 1286 case Qualifiers::OCL_Autoreleasing: 1287 assert(Ownership != Qualifiers::OCL_Autoreleasing); 1288 Flag = 0; 1289 } 1290 return Flag; 1291 } 1292 llvm::Constant *GenerateIvarList(ArrayRef<llvm::Constant *> IvarNames, 1293 ArrayRef<llvm::Constant *> IvarTypes, 1294 ArrayRef<llvm::Constant *> IvarOffsets, 1295 ArrayRef<llvm::Constant *> IvarAlign, 1296 ArrayRef<Qualifiers::ObjCLifetime> IvarOwnership) override { 1297 llvm_unreachable("Method should not be called!"); 1298 } 1299 1300 llvm::Constant *GenerateEmptyProtocol(StringRef ProtocolName) override { 1301 std::string Name = SymbolForProtocol(ProtocolName); 1302 auto *GV = TheModule.getGlobalVariable(Name); 1303 if (!GV) { 1304 // Emit a placeholder symbol. 1305 GV = new llvm::GlobalVariable(TheModule, ProtocolTy, false, 1306 llvm::GlobalValue::ExternalLinkage, nullptr, Name); 1307 GV->setAlignment(CGM.getPointerAlign().getAsAlign()); 1308 } 1309 return llvm::ConstantExpr::getBitCast(GV, ProtocolPtrTy); 1310 } 1311 1312 /// Existing protocol references. 1313 llvm::StringMap<llvm::Constant*> ExistingProtocolRefs; 1314 1315 llvm::Value *GenerateProtocolRef(CodeGenFunction &CGF, 1316 const ObjCProtocolDecl *PD) override { 1317 auto Name = PD->getNameAsString(); 1318 auto *&Ref = ExistingProtocolRefs[Name]; 1319 if (!Ref) { 1320 auto *&Protocol = ExistingProtocols[Name]; 1321 if (!Protocol) 1322 Protocol = GenerateProtocolRef(PD); 1323 std::string RefName = SymbolForProtocolRef(Name); 1324 assert(!TheModule.getGlobalVariable(RefName)); 1325 // Emit a reference symbol. 1326 auto GV = new llvm::GlobalVariable(TheModule, ProtocolPtrTy, 1327 false, llvm::GlobalValue::LinkOnceODRLinkage, 1328 llvm::ConstantExpr::getBitCast(Protocol, ProtocolPtrTy), RefName); 1329 GV->setComdat(TheModule.getOrInsertComdat(RefName)); 1330 GV->setSection(sectionName<ProtocolReferenceSection>()); 1331 GV->setAlignment(CGM.getPointerAlign().getAsAlign()); 1332 Ref = GV; 1333 } 1334 EmittedProtocolRef = true; 1335 return CGF.Builder.CreateAlignedLoad(ProtocolPtrTy, Ref, 1336 CGM.getPointerAlign()); 1337 } 1338 1339 llvm::Constant *GenerateProtocolList(ArrayRef<llvm::Constant*> Protocols) { 1340 llvm::ArrayType *ProtocolArrayTy = llvm::ArrayType::get(ProtocolPtrTy, 1341 Protocols.size()); 1342 llvm::Constant * ProtocolArray = llvm::ConstantArray::get(ProtocolArrayTy, 1343 Protocols); 1344 ConstantInitBuilder builder(CGM); 1345 auto ProtocolBuilder = builder.beginStruct(); 1346 ProtocolBuilder.addNullPointer(PtrTy); 1347 ProtocolBuilder.addInt(SizeTy, Protocols.size()); 1348 ProtocolBuilder.add(ProtocolArray); 1349 return ProtocolBuilder.finishAndCreateGlobal(".objc_protocol_list", 1350 CGM.getPointerAlign(), false, llvm::GlobalValue::InternalLinkage); 1351 } 1352 1353 void GenerateProtocol(const ObjCProtocolDecl *PD) override { 1354 // Do nothing - we only emit referenced protocols. 1355 } 1356 llvm::Constant *GenerateProtocolRef(const ObjCProtocolDecl *PD) override { 1357 std::string ProtocolName = PD->getNameAsString(); 1358 auto *&Protocol = ExistingProtocols[ProtocolName]; 1359 if (Protocol) 1360 return Protocol; 1361 1362 EmittedProtocol = true; 1363 1364 auto SymName = SymbolForProtocol(ProtocolName); 1365 auto *OldGV = TheModule.getGlobalVariable(SymName); 1366 1367 // Use the protocol definition, if there is one. 1368 if (const ObjCProtocolDecl *Def = PD->getDefinition()) 1369 PD = Def; 1370 else { 1371 // If there is no definition, then create an external linkage symbol and 1372 // hope that someone else fills it in for us (and fail to link if they 1373 // don't). 1374 assert(!OldGV); 1375 Protocol = new llvm::GlobalVariable(TheModule, ProtocolTy, 1376 /*isConstant*/false, 1377 llvm::GlobalValue::ExternalLinkage, nullptr, SymName); 1378 return Protocol; 1379 } 1380 1381 SmallVector<llvm::Constant*, 16> Protocols; 1382 auto RuntimeProtocols = 1383 GetRuntimeProtocolList(PD->protocol_begin(), PD->protocol_end()); 1384 for (const auto *PI : RuntimeProtocols) 1385 Protocols.push_back( 1386 llvm::ConstantExpr::getBitCast(GenerateProtocolRef(PI), 1387 ProtocolPtrTy)); 1388 llvm::Constant *ProtocolList = GenerateProtocolList(Protocols); 1389 1390 // Collect information about methods 1391 llvm::Constant *InstanceMethodList, *OptionalInstanceMethodList; 1392 llvm::Constant *ClassMethodList, *OptionalClassMethodList; 1393 EmitProtocolMethodList(PD->instance_methods(), InstanceMethodList, 1394 OptionalInstanceMethodList); 1395 EmitProtocolMethodList(PD->class_methods(), ClassMethodList, 1396 OptionalClassMethodList); 1397 1398 // The isa pointer must be set to a magic number so the runtime knows it's 1399 // the correct layout. 1400 ConstantInitBuilder builder(CGM); 1401 auto ProtocolBuilder = builder.beginStruct(); 1402 ProtocolBuilder.add(llvm::ConstantExpr::getIntToPtr( 1403 llvm::ConstantInt::get(Int32Ty, ProtocolVersion), IdTy)); 1404 ProtocolBuilder.add(MakeConstantString(ProtocolName)); 1405 ProtocolBuilder.add(ProtocolList); 1406 ProtocolBuilder.add(InstanceMethodList); 1407 ProtocolBuilder.add(ClassMethodList); 1408 ProtocolBuilder.add(OptionalInstanceMethodList); 1409 ProtocolBuilder.add(OptionalClassMethodList); 1410 // Required instance properties 1411 ProtocolBuilder.add(GeneratePropertyList(nullptr, PD, false, false)); 1412 // Optional instance properties 1413 ProtocolBuilder.add(GeneratePropertyList(nullptr, PD, false, true)); 1414 // Required class properties 1415 ProtocolBuilder.add(GeneratePropertyList(nullptr, PD, true, false)); 1416 // Optional class properties 1417 ProtocolBuilder.add(GeneratePropertyList(nullptr, PD, true, true)); 1418 1419 auto *GV = ProtocolBuilder.finishAndCreateGlobal(SymName, 1420 CGM.getPointerAlign(), false, llvm::GlobalValue::ExternalLinkage); 1421 GV->setSection(sectionName<ProtocolSection>()); 1422 GV->setComdat(TheModule.getOrInsertComdat(SymName)); 1423 if (OldGV) { 1424 OldGV->replaceAllUsesWith(llvm::ConstantExpr::getBitCast(GV, 1425 OldGV->getType())); 1426 OldGV->removeFromParent(); 1427 GV->setName(SymName); 1428 } 1429 Protocol = GV; 1430 return GV; 1431 } 1432 llvm::Constant *EnforceType(llvm::Constant *Val, llvm::Type *Ty) { 1433 if (Val->getType() == Ty) 1434 return Val; 1435 return llvm::ConstantExpr::getBitCast(Val, Ty); 1436 } 1437 llvm::Value *GetTypedSelector(CodeGenFunction &CGF, Selector Sel, 1438 const std::string &TypeEncoding) override { 1439 return GetConstantSelector(Sel, TypeEncoding); 1440 } 1441 llvm::Constant *GetTypeString(llvm::StringRef TypeEncoding) { 1442 if (TypeEncoding.empty()) 1443 return NULLPtr; 1444 std::string MangledTypes = std::string(TypeEncoding); 1445 std::replace(MangledTypes.begin(), MangledTypes.end(), 1446 '@', '\1'); 1447 std::string TypesVarName = ".objc_sel_types_" + MangledTypes; 1448 auto *TypesGlobal = TheModule.getGlobalVariable(TypesVarName); 1449 if (!TypesGlobal) { 1450 llvm::Constant *Init = llvm::ConstantDataArray::getString(VMContext, 1451 TypeEncoding); 1452 auto *GV = new llvm::GlobalVariable(TheModule, Init->getType(), 1453 true, llvm::GlobalValue::LinkOnceODRLinkage, Init, TypesVarName); 1454 GV->setComdat(TheModule.getOrInsertComdat(TypesVarName)); 1455 GV->setVisibility(llvm::GlobalValue::HiddenVisibility); 1456 TypesGlobal = GV; 1457 } 1458 return llvm::ConstantExpr::getGetElementPtr(TypesGlobal->getValueType(), 1459 TypesGlobal, Zeros); 1460 } 1461 llvm::Constant *GetConstantSelector(Selector Sel, 1462 const std::string &TypeEncoding) override { 1463 // @ is used as a special character in symbol names (used for symbol 1464 // versioning), so mangle the name to not include it. Replace it with a 1465 // character that is not a valid type encoding character (and, being 1466 // non-printable, never will be!) 1467 std::string MangledTypes = TypeEncoding; 1468 std::replace(MangledTypes.begin(), MangledTypes.end(), 1469 '@', '\1'); 1470 auto SelVarName = (StringRef(".objc_selector_") + Sel.getAsString() + "_" + 1471 MangledTypes).str(); 1472 if (auto *GV = TheModule.getNamedGlobal(SelVarName)) 1473 return EnforceType(GV, SelectorTy); 1474 ConstantInitBuilder builder(CGM); 1475 auto SelBuilder = builder.beginStruct(); 1476 SelBuilder.add(ExportUniqueString(Sel.getAsString(), ".objc_sel_name_", 1477 true)); 1478 SelBuilder.add(GetTypeString(TypeEncoding)); 1479 auto *GV = SelBuilder.finishAndCreateGlobal(SelVarName, 1480 CGM.getPointerAlign(), false, llvm::GlobalValue::LinkOnceODRLinkage); 1481 GV->setComdat(TheModule.getOrInsertComdat(SelVarName)); 1482 GV->setVisibility(llvm::GlobalValue::HiddenVisibility); 1483 GV->setSection(sectionName<SelectorSection>()); 1484 auto *SelVal = EnforceType(GV, SelectorTy); 1485 return SelVal; 1486 } 1487 llvm::StructType *emptyStruct = nullptr; 1488 1489 /// Return pointers to the start and end of a section. On ELF platforms, we 1490 /// use the __start_ and __stop_ symbols that GNU-compatible linkers will set 1491 /// to the start and end of section names, as long as those section names are 1492 /// valid identifiers and the symbols are referenced but not defined. On 1493 /// Windows, we use the fact that MSVC-compatible linkers will lexically sort 1494 /// by subsections and place everything that we want to reference in a middle 1495 /// subsection and then insert zero-sized symbols in subsections a and z. 1496 std::pair<llvm::Constant*,llvm::Constant*> 1497 GetSectionBounds(StringRef Section) { 1498 if (CGM.getTriple().isOSBinFormatCOFF()) { 1499 if (emptyStruct == nullptr) { 1500 emptyStruct = llvm::StructType::create(VMContext, ".objc_section_sentinel"); 1501 emptyStruct->setBody({}, /*isPacked*/true); 1502 } 1503 auto ZeroInit = llvm::Constant::getNullValue(emptyStruct); 1504 auto Sym = [&](StringRef Prefix, StringRef SecSuffix) { 1505 auto *Sym = new llvm::GlobalVariable(TheModule, emptyStruct, 1506 /*isConstant*/false, 1507 llvm::GlobalValue::LinkOnceODRLinkage, ZeroInit, Prefix + 1508 Section); 1509 Sym->setVisibility(llvm::GlobalValue::HiddenVisibility); 1510 Sym->setSection((Section + SecSuffix).str()); 1511 Sym->setComdat(TheModule.getOrInsertComdat((Prefix + 1512 Section).str())); 1513 Sym->setAlignment(CGM.getPointerAlign().getAsAlign()); 1514 return Sym; 1515 }; 1516 return { Sym("__start_", "$a"), Sym("__stop", "$z") }; 1517 } 1518 auto *Start = new llvm::GlobalVariable(TheModule, PtrTy, 1519 /*isConstant*/false, 1520 llvm::GlobalValue::ExternalLinkage, nullptr, StringRef("__start_") + 1521 Section); 1522 Start->setVisibility(llvm::GlobalValue::HiddenVisibility); 1523 auto *Stop = new llvm::GlobalVariable(TheModule, PtrTy, 1524 /*isConstant*/false, 1525 llvm::GlobalValue::ExternalLinkage, nullptr, StringRef("__stop_") + 1526 Section); 1527 Stop->setVisibility(llvm::GlobalValue::HiddenVisibility); 1528 return { Start, Stop }; 1529 } 1530 CatchTypeInfo getCatchAllTypeInfo() override { 1531 return CGM.getCXXABI().getCatchAllTypeInfo(); 1532 } 1533 llvm::Function *ModuleInitFunction() override { 1534 llvm::Function *LoadFunction = llvm::Function::Create( 1535 llvm::FunctionType::get(llvm::Type::getVoidTy(VMContext), false), 1536 llvm::GlobalValue::LinkOnceODRLinkage, ".objcv2_load_function", 1537 &TheModule); 1538 LoadFunction->setVisibility(llvm::GlobalValue::HiddenVisibility); 1539 LoadFunction->setComdat(TheModule.getOrInsertComdat(".objcv2_load_function")); 1540 1541 llvm::BasicBlock *EntryBB = 1542 llvm::BasicBlock::Create(VMContext, "entry", LoadFunction); 1543 CGBuilderTy B(CGM, VMContext); 1544 B.SetInsertPoint(EntryBB); 1545 ConstantInitBuilder builder(CGM); 1546 auto InitStructBuilder = builder.beginStruct(); 1547 InitStructBuilder.addInt(Int64Ty, 0); 1548 auto §ionVec = CGM.getTriple().isOSBinFormatCOFF() ? PECOFFSectionsBaseNames : SectionsBaseNames; 1549 for (auto *s : sectionVec) { 1550 auto bounds = GetSectionBounds(s); 1551 InitStructBuilder.add(bounds.first); 1552 InitStructBuilder.add(bounds.second); 1553 } 1554 auto *InitStruct = InitStructBuilder.finishAndCreateGlobal(".objc_init", 1555 CGM.getPointerAlign(), false, llvm::GlobalValue::LinkOnceODRLinkage); 1556 InitStruct->setVisibility(llvm::GlobalValue::HiddenVisibility); 1557 InitStruct->setComdat(TheModule.getOrInsertComdat(".objc_init")); 1558 1559 CallRuntimeFunction(B, "__objc_load", {InitStruct});; 1560 B.CreateRetVoid(); 1561 // Make sure that the optimisers don't delete this function. 1562 CGM.addCompilerUsedGlobal(LoadFunction); 1563 // FIXME: Currently ELF only! 1564 // We have to do this by hand, rather than with @llvm.ctors, so that the 1565 // linker can remove the duplicate invocations. 1566 auto *InitVar = new llvm::GlobalVariable(TheModule, LoadFunction->getType(), 1567 /*isConstant*/false, llvm::GlobalValue::LinkOnceAnyLinkage, 1568 LoadFunction, ".objc_ctor"); 1569 // Check that this hasn't been renamed. This shouldn't happen, because 1570 // this function should be called precisely once. 1571 assert(InitVar->getName() == ".objc_ctor"); 1572 // In Windows, initialisers are sorted by the suffix. XCL is for library 1573 // initialisers, which run before user initialisers. We are running 1574 // Objective-C loads at the end of library load. This means +load methods 1575 // will run before any other static constructors, but that static 1576 // constructors can see a fully initialised Objective-C state. 1577 if (CGM.getTriple().isOSBinFormatCOFF()) 1578 InitVar->setSection(".CRT$XCLz"); 1579 else 1580 { 1581 if (CGM.getCodeGenOpts().UseInitArray) 1582 InitVar->setSection(".init_array"); 1583 else 1584 InitVar->setSection(".ctors"); 1585 } 1586 InitVar->setVisibility(llvm::GlobalValue::HiddenVisibility); 1587 InitVar->setComdat(TheModule.getOrInsertComdat(".objc_ctor")); 1588 CGM.addUsedGlobal(InitVar); 1589 for (auto *C : Categories) { 1590 auto *Cat = cast<llvm::GlobalVariable>(C->stripPointerCasts()); 1591 Cat->setSection(sectionName<CategorySection>()); 1592 CGM.addUsedGlobal(Cat); 1593 } 1594 auto createNullGlobal = [&](StringRef Name, ArrayRef<llvm::Constant*> Init, 1595 StringRef Section) { 1596 auto nullBuilder = builder.beginStruct(); 1597 for (auto *F : Init) 1598 nullBuilder.add(F); 1599 auto GV = nullBuilder.finishAndCreateGlobal(Name, CGM.getPointerAlign(), 1600 false, llvm::GlobalValue::LinkOnceODRLinkage); 1601 GV->setSection(Section); 1602 GV->setComdat(TheModule.getOrInsertComdat(Name)); 1603 GV->setVisibility(llvm::GlobalValue::HiddenVisibility); 1604 CGM.addUsedGlobal(GV); 1605 return GV; 1606 }; 1607 for (auto clsAlias : ClassAliases) 1608 createNullGlobal(std::string(".objc_class_alias") + 1609 clsAlias.second, { MakeConstantString(clsAlias.second), 1610 GetClassVar(clsAlias.first) }, sectionName<ClassAliasSection>()); 1611 // On ELF platforms, add a null value for each special section so that we 1612 // can always guarantee that the _start and _stop symbols will exist and be 1613 // meaningful. This is not required on COFF platforms, where our start and 1614 // stop symbols will create the section. 1615 if (!CGM.getTriple().isOSBinFormatCOFF()) { 1616 createNullGlobal(".objc_null_selector", {NULLPtr, NULLPtr}, 1617 sectionName<SelectorSection>()); 1618 if (Categories.empty()) 1619 createNullGlobal(".objc_null_category", {NULLPtr, NULLPtr, 1620 NULLPtr, NULLPtr, NULLPtr, NULLPtr, NULLPtr}, 1621 sectionName<CategorySection>()); 1622 if (!EmittedClass) { 1623 createNullGlobal(".objc_null_cls_init_ref", NULLPtr, 1624 sectionName<ClassSection>()); 1625 createNullGlobal(".objc_null_class_ref", { NULLPtr, NULLPtr }, 1626 sectionName<ClassReferenceSection>()); 1627 } 1628 if (!EmittedProtocol) 1629 createNullGlobal(".objc_null_protocol", {NULLPtr, NULLPtr, NULLPtr, 1630 NULLPtr, NULLPtr, NULLPtr, NULLPtr, NULLPtr, NULLPtr, NULLPtr, 1631 NULLPtr}, sectionName<ProtocolSection>()); 1632 if (!EmittedProtocolRef) 1633 createNullGlobal(".objc_null_protocol_ref", {NULLPtr}, 1634 sectionName<ProtocolReferenceSection>()); 1635 if (ClassAliases.empty()) 1636 createNullGlobal(".objc_null_class_alias", { NULLPtr, NULLPtr }, 1637 sectionName<ClassAliasSection>()); 1638 if (ConstantStrings.empty()) { 1639 auto i32Zero = llvm::ConstantInt::get(Int32Ty, 0); 1640 createNullGlobal(".objc_null_constant_string", { NULLPtr, i32Zero, 1641 i32Zero, i32Zero, i32Zero, NULLPtr }, 1642 sectionName<ConstantStringSection>()); 1643 } 1644 } 1645 ConstantStrings.clear(); 1646 Categories.clear(); 1647 Classes.clear(); 1648 1649 if (EarlyInitList.size() > 0) { 1650 auto *Init = llvm::Function::Create(llvm::FunctionType::get(CGM.VoidTy, 1651 {}), llvm::GlobalValue::InternalLinkage, ".objc_early_init", 1652 &CGM.getModule()); 1653 llvm::IRBuilder<> b(llvm::BasicBlock::Create(CGM.getLLVMContext(), "entry", 1654 Init)); 1655 for (const auto &lateInit : EarlyInitList) { 1656 auto *global = TheModule.getGlobalVariable(lateInit.first); 1657 if (global) { 1658 llvm::GlobalVariable *GV = lateInit.second.first; 1659 b.CreateAlignedStore( 1660 global, 1661 b.CreateStructGEP(GV->getValueType(), GV, lateInit.second.second), 1662 CGM.getPointerAlign().getAsAlign()); 1663 } 1664 } 1665 b.CreateRetVoid(); 1666 // We can't use the normal LLVM global initialisation array, because we 1667 // need to specify that this runs early in library initialisation. 1668 auto *InitVar = new llvm::GlobalVariable(CGM.getModule(), Init->getType(), 1669 /*isConstant*/true, llvm::GlobalValue::InternalLinkage, 1670 Init, ".objc_early_init_ptr"); 1671 InitVar->setSection(".CRT$XCLb"); 1672 CGM.addUsedGlobal(InitVar); 1673 } 1674 return nullptr; 1675 } 1676 /// In the v2 ABI, ivar offset variables use the type encoding in their name 1677 /// to trigger linker failures if the types don't match. 1678 std::string GetIVarOffsetVariableName(const ObjCInterfaceDecl *ID, 1679 const ObjCIvarDecl *Ivar) override { 1680 std::string TypeEncoding; 1681 CGM.getContext().getObjCEncodingForType(Ivar->getType(), TypeEncoding); 1682 // Prevent the @ from being interpreted as a symbol version. 1683 std::replace(TypeEncoding.begin(), TypeEncoding.end(), 1684 '@', '\1'); 1685 const std::string Name = "__objc_ivar_offset_" + ID->getNameAsString() 1686 + '.' + Ivar->getNameAsString() + '.' + TypeEncoding; 1687 return Name; 1688 } 1689 llvm::Value *EmitIvarOffset(CodeGenFunction &CGF, 1690 const ObjCInterfaceDecl *Interface, 1691 const ObjCIvarDecl *Ivar) override { 1692 const std::string Name = GetIVarOffsetVariableName(Ivar->getContainingInterface(), Ivar); 1693 llvm::GlobalVariable *IvarOffsetPointer = TheModule.getNamedGlobal(Name); 1694 if (!IvarOffsetPointer) 1695 IvarOffsetPointer = new llvm::GlobalVariable(TheModule, IntTy, false, 1696 llvm::GlobalValue::ExternalLinkage, nullptr, Name); 1697 CharUnits Align = CGM.getIntAlign(); 1698 llvm::Value *Offset = 1699 CGF.Builder.CreateAlignedLoad(IntTy, IvarOffsetPointer, Align); 1700 if (Offset->getType() != PtrDiffTy) 1701 Offset = CGF.Builder.CreateZExtOrBitCast(Offset, PtrDiffTy); 1702 return Offset; 1703 } 1704 void GenerateClass(const ObjCImplementationDecl *OID) override { 1705 ASTContext &Context = CGM.getContext(); 1706 bool IsCOFF = CGM.getTriple().isOSBinFormatCOFF(); 1707 1708 // Get the class name 1709 ObjCInterfaceDecl *classDecl = 1710 const_cast<ObjCInterfaceDecl *>(OID->getClassInterface()); 1711 std::string className = classDecl->getNameAsString(); 1712 auto *classNameConstant = MakeConstantString(className); 1713 1714 ConstantInitBuilder builder(CGM); 1715 auto metaclassFields = builder.beginStruct(); 1716 // struct objc_class *isa; 1717 metaclassFields.addNullPointer(PtrTy); 1718 // struct objc_class *super_class; 1719 metaclassFields.addNullPointer(PtrTy); 1720 // const char *name; 1721 metaclassFields.add(classNameConstant); 1722 // long version; 1723 metaclassFields.addInt(LongTy, 0); 1724 // unsigned long info; 1725 // objc_class_flag_meta 1726 metaclassFields.addInt(LongTy, 1); 1727 // long instance_size; 1728 // Setting this to zero is consistent with the older ABI, but it might be 1729 // more sensible to set this to sizeof(struct objc_class) 1730 metaclassFields.addInt(LongTy, 0); 1731 // struct objc_ivar_list *ivars; 1732 metaclassFields.addNullPointer(PtrTy); 1733 // struct objc_method_list *methods 1734 // FIXME: Almost identical code is copied and pasted below for the 1735 // class, but refactoring it cleanly requires C++14 generic lambdas. 1736 if (OID->classmeth_begin() == OID->classmeth_end()) 1737 metaclassFields.addNullPointer(PtrTy); 1738 else { 1739 SmallVector<ObjCMethodDecl*, 16> ClassMethods; 1740 ClassMethods.insert(ClassMethods.begin(), OID->classmeth_begin(), 1741 OID->classmeth_end()); 1742 metaclassFields.addBitCast( 1743 GenerateMethodList(className, "", ClassMethods, true), 1744 PtrTy); 1745 } 1746 // void *dtable; 1747 metaclassFields.addNullPointer(PtrTy); 1748 // IMP cxx_construct; 1749 metaclassFields.addNullPointer(PtrTy); 1750 // IMP cxx_destruct; 1751 metaclassFields.addNullPointer(PtrTy); 1752 // struct objc_class *subclass_list 1753 metaclassFields.addNullPointer(PtrTy); 1754 // struct objc_class *sibling_class 1755 metaclassFields.addNullPointer(PtrTy); 1756 // struct objc_protocol_list *protocols; 1757 metaclassFields.addNullPointer(PtrTy); 1758 // struct reference_list *extra_data; 1759 metaclassFields.addNullPointer(PtrTy); 1760 // long abi_version; 1761 metaclassFields.addInt(LongTy, 0); 1762 // struct objc_property_list *properties 1763 metaclassFields.add(GeneratePropertyList(OID, classDecl, /*isClassProperty*/true)); 1764 1765 auto *metaclass = metaclassFields.finishAndCreateGlobal( 1766 ManglePublicSymbol("OBJC_METACLASS_") + className, 1767 CGM.getPointerAlign()); 1768 1769 auto classFields = builder.beginStruct(); 1770 // struct objc_class *isa; 1771 classFields.add(metaclass); 1772 // struct objc_class *super_class; 1773 // Get the superclass name. 1774 const ObjCInterfaceDecl * SuperClassDecl = 1775 OID->getClassInterface()->getSuperClass(); 1776 llvm::Constant *SuperClass = nullptr; 1777 if (SuperClassDecl) { 1778 auto SuperClassName = SymbolForClass(SuperClassDecl->getNameAsString()); 1779 SuperClass = TheModule.getNamedGlobal(SuperClassName); 1780 if (!SuperClass) 1781 { 1782 SuperClass = new llvm::GlobalVariable(TheModule, PtrTy, false, 1783 llvm::GlobalValue::ExternalLinkage, nullptr, SuperClassName); 1784 if (IsCOFF) { 1785 auto Storage = llvm::GlobalValue::DefaultStorageClass; 1786 if (SuperClassDecl->hasAttr<DLLImportAttr>()) 1787 Storage = llvm::GlobalValue::DLLImportStorageClass; 1788 else if (SuperClassDecl->hasAttr<DLLExportAttr>()) 1789 Storage = llvm::GlobalValue::DLLExportStorageClass; 1790 1791 cast<llvm::GlobalValue>(SuperClass)->setDLLStorageClass(Storage); 1792 } 1793 } 1794 if (!IsCOFF) 1795 classFields.add(llvm::ConstantExpr::getBitCast(SuperClass, PtrTy)); 1796 else 1797 classFields.addNullPointer(PtrTy); 1798 } else 1799 classFields.addNullPointer(PtrTy); 1800 // const char *name; 1801 classFields.add(classNameConstant); 1802 // long version; 1803 classFields.addInt(LongTy, 0); 1804 // unsigned long info; 1805 // !objc_class_flag_meta 1806 classFields.addInt(LongTy, 0); 1807 // long instance_size; 1808 int superInstanceSize = !SuperClassDecl ? 0 : 1809 Context.getASTObjCInterfaceLayout(SuperClassDecl).getSize().getQuantity(); 1810 // Instance size is negative for classes that have not yet had their ivar 1811 // layout calculated. 1812 classFields.addInt(LongTy, 1813 0 - (Context.getASTObjCImplementationLayout(OID).getSize().getQuantity() - 1814 superInstanceSize)); 1815 1816 if (classDecl->all_declared_ivar_begin() == nullptr) 1817 classFields.addNullPointer(PtrTy); 1818 else { 1819 int ivar_count = 0; 1820 for (const ObjCIvarDecl *IVD = classDecl->all_declared_ivar_begin(); IVD; 1821 IVD = IVD->getNextIvar()) ivar_count++; 1822 llvm::DataLayout td(&TheModule); 1823 // struct objc_ivar_list *ivars; 1824 ConstantInitBuilder b(CGM); 1825 auto ivarListBuilder = b.beginStruct(); 1826 // int count; 1827 ivarListBuilder.addInt(IntTy, ivar_count); 1828 // size_t size; 1829 llvm::StructType *ObjCIvarTy = llvm::StructType::get( 1830 PtrToInt8Ty, 1831 PtrToInt8Ty, 1832 PtrToInt8Ty, 1833 Int32Ty, 1834 Int32Ty); 1835 ivarListBuilder.addInt(SizeTy, td.getTypeSizeInBits(ObjCIvarTy) / 1836 CGM.getContext().getCharWidth()); 1837 // struct objc_ivar ivars[] 1838 auto ivarArrayBuilder = ivarListBuilder.beginArray(); 1839 for (const ObjCIvarDecl *IVD = classDecl->all_declared_ivar_begin(); IVD; 1840 IVD = IVD->getNextIvar()) { 1841 auto ivarTy = IVD->getType(); 1842 auto ivarBuilder = ivarArrayBuilder.beginStruct(); 1843 // const char *name; 1844 ivarBuilder.add(MakeConstantString(IVD->getNameAsString())); 1845 // const char *type; 1846 std::string TypeStr; 1847 //Context.getObjCEncodingForType(ivarTy, TypeStr, IVD, true); 1848 Context.getObjCEncodingForMethodParameter(Decl::OBJC_TQ_None, ivarTy, TypeStr, true); 1849 ivarBuilder.add(MakeConstantString(TypeStr)); 1850 // int *offset; 1851 uint64_t BaseOffset = ComputeIvarBaseOffset(CGM, OID, IVD); 1852 uint64_t Offset = BaseOffset - superInstanceSize; 1853 llvm::Constant *OffsetValue = llvm::ConstantInt::get(IntTy, Offset); 1854 std::string OffsetName = GetIVarOffsetVariableName(classDecl, IVD); 1855 llvm::GlobalVariable *OffsetVar = TheModule.getGlobalVariable(OffsetName); 1856 if (OffsetVar) 1857 OffsetVar->setInitializer(OffsetValue); 1858 else 1859 OffsetVar = new llvm::GlobalVariable(TheModule, IntTy, 1860 false, llvm::GlobalValue::ExternalLinkage, 1861 OffsetValue, OffsetName); 1862 auto ivarVisibility = 1863 (IVD->getAccessControl() == ObjCIvarDecl::Private || 1864 IVD->getAccessControl() == ObjCIvarDecl::Package || 1865 classDecl->getVisibility() == HiddenVisibility) ? 1866 llvm::GlobalValue::HiddenVisibility : 1867 llvm::GlobalValue::DefaultVisibility; 1868 OffsetVar->setVisibility(ivarVisibility); 1869 ivarBuilder.add(OffsetVar); 1870 // Ivar size 1871 ivarBuilder.addInt(Int32Ty, 1872 CGM.getContext().getTypeSizeInChars(ivarTy).getQuantity()); 1873 // Alignment will be stored as a base-2 log of the alignment. 1874 unsigned align = 1875 llvm::Log2_32(Context.getTypeAlignInChars(ivarTy).getQuantity()); 1876 // Objects that require more than 2^64-byte alignment should be impossible! 1877 assert(align < 64); 1878 // uint32_t flags; 1879 // Bits 0-1 are ownership. 1880 // Bit 2 indicates an extended type encoding 1881 // Bits 3-8 contain log2(aligment) 1882 ivarBuilder.addInt(Int32Ty, 1883 (align << 3) | (1<<2) | 1884 FlagsForOwnership(ivarTy.getQualifiers().getObjCLifetime())); 1885 ivarBuilder.finishAndAddTo(ivarArrayBuilder); 1886 } 1887 ivarArrayBuilder.finishAndAddTo(ivarListBuilder); 1888 auto ivarList = ivarListBuilder.finishAndCreateGlobal(".objc_ivar_list", 1889 CGM.getPointerAlign(), /*constant*/ false, 1890 llvm::GlobalValue::PrivateLinkage); 1891 classFields.add(ivarList); 1892 } 1893 // struct objc_method_list *methods 1894 SmallVector<const ObjCMethodDecl*, 16> InstanceMethods; 1895 InstanceMethods.insert(InstanceMethods.begin(), OID->instmeth_begin(), 1896 OID->instmeth_end()); 1897 for (auto *propImpl : OID->property_impls()) 1898 if (propImpl->getPropertyImplementation() == 1899 ObjCPropertyImplDecl::Synthesize) { 1900 auto addIfExists = [&](const ObjCMethodDecl *OMD) { 1901 if (OMD && OMD->hasBody()) 1902 InstanceMethods.push_back(OMD); 1903 }; 1904 addIfExists(propImpl->getGetterMethodDecl()); 1905 addIfExists(propImpl->getSetterMethodDecl()); 1906 } 1907 1908 if (InstanceMethods.size() == 0) 1909 classFields.addNullPointer(PtrTy); 1910 else 1911 classFields.addBitCast( 1912 GenerateMethodList(className, "", InstanceMethods, false), 1913 PtrTy); 1914 // void *dtable; 1915 classFields.addNullPointer(PtrTy); 1916 // IMP cxx_construct; 1917 classFields.addNullPointer(PtrTy); 1918 // IMP cxx_destruct; 1919 classFields.addNullPointer(PtrTy); 1920 // struct objc_class *subclass_list 1921 classFields.addNullPointer(PtrTy); 1922 // struct objc_class *sibling_class 1923 classFields.addNullPointer(PtrTy); 1924 // struct objc_protocol_list *protocols; 1925 auto RuntimeProtocols = GetRuntimeProtocolList(classDecl->protocol_begin(), 1926 classDecl->protocol_end()); 1927 SmallVector<llvm::Constant *, 16> Protocols; 1928 for (const auto *I : RuntimeProtocols) 1929 Protocols.push_back( 1930 llvm::ConstantExpr::getBitCast(GenerateProtocolRef(I), 1931 ProtocolPtrTy)); 1932 if (Protocols.empty()) 1933 classFields.addNullPointer(PtrTy); 1934 else 1935 classFields.add(GenerateProtocolList(Protocols)); 1936 // struct reference_list *extra_data; 1937 classFields.addNullPointer(PtrTy); 1938 // long abi_version; 1939 classFields.addInt(LongTy, 0); 1940 // struct objc_property_list *properties 1941 classFields.add(GeneratePropertyList(OID, classDecl)); 1942 1943 llvm::GlobalVariable *classStruct = 1944 classFields.finishAndCreateGlobal(SymbolForClass(className), 1945 CGM.getPointerAlign(), false, llvm::GlobalValue::ExternalLinkage); 1946 1947 auto *classRefSymbol = GetClassVar(className); 1948 classRefSymbol->setSection(sectionName<ClassReferenceSection>()); 1949 classRefSymbol->setInitializer(llvm::ConstantExpr::getBitCast(classStruct, IdTy)); 1950 1951 if (IsCOFF) { 1952 // we can't import a class struct. 1953 if (OID->getClassInterface()->hasAttr<DLLExportAttr>()) { 1954 classStruct->setDLLStorageClass(llvm::GlobalValue::DLLExportStorageClass); 1955 cast<llvm::GlobalValue>(classRefSymbol)->setDLLStorageClass(llvm::GlobalValue::DLLExportStorageClass); 1956 } 1957 1958 if (SuperClass) { 1959 std::pair<llvm::GlobalVariable*, int> v{classStruct, 1}; 1960 EarlyInitList.emplace_back(std::string(SuperClass->getName()), 1961 std::move(v)); 1962 } 1963 1964 } 1965 1966 1967 // Resolve the class aliases, if they exist. 1968 // FIXME: Class pointer aliases shouldn't exist! 1969 if (ClassPtrAlias) { 1970 ClassPtrAlias->replaceAllUsesWith( 1971 llvm::ConstantExpr::getBitCast(classStruct, IdTy)); 1972 ClassPtrAlias->eraseFromParent(); 1973 ClassPtrAlias = nullptr; 1974 } 1975 if (auto Placeholder = 1976 TheModule.getNamedGlobal(SymbolForClass(className))) 1977 if (Placeholder != classStruct) { 1978 Placeholder->replaceAllUsesWith( 1979 llvm::ConstantExpr::getBitCast(classStruct, Placeholder->getType())); 1980 Placeholder->eraseFromParent(); 1981 classStruct->setName(SymbolForClass(className)); 1982 } 1983 if (MetaClassPtrAlias) { 1984 MetaClassPtrAlias->replaceAllUsesWith( 1985 llvm::ConstantExpr::getBitCast(metaclass, IdTy)); 1986 MetaClassPtrAlias->eraseFromParent(); 1987 MetaClassPtrAlias = nullptr; 1988 } 1989 assert(classStruct->getName() == SymbolForClass(className)); 1990 1991 auto classInitRef = new llvm::GlobalVariable(TheModule, 1992 classStruct->getType(), false, llvm::GlobalValue::ExternalLinkage, 1993 classStruct, ManglePublicSymbol("OBJC_INIT_CLASS_") + className); 1994 classInitRef->setSection(sectionName<ClassSection>()); 1995 CGM.addUsedGlobal(classInitRef); 1996 1997 EmittedClass = true; 1998 } 1999 public: 2000 CGObjCGNUstep2(CodeGenModule &Mod) : CGObjCGNUstep(Mod, 10, 4, 2) { 2001 MsgLookupSuperFn.init(&CGM, "objc_msg_lookup_super", IMPTy, 2002 PtrToObjCSuperTy, SelectorTy); 2003 // struct objc_property 2004 // { 2005 // const char *name; 2006 // const char *attributes; 2007 // const char *type; 2008 // SEL getter; 2009 // SEL setter; 2010 // } 2011 PropertyMetadataTy = 2012 llvm::StructType::get(CGM.getLLVMContext(), 2013 { PtrToInt8Ty, PtrToInt8Ty, PtrToInt8Ty, PtrToInt8Ty, PtrToInt8Ty }); 2014 } 2015 2016 }; 2017 2018 const char *const CGObjCGNUstep2::SectionsBaseNames[8] = 2019 { 2020 "__objc_selectors", 2021 "__objc_classes", 2022 "__objc_class_refs", 2023 "__objc_cats", 2024 "__objc_protocols", 2025 "__objc_protocol_refs", 2026 "__objc_class_aliases", 2027 "__objc_constant_string" 2028 }; 2029 2030 const char *const CGObjCGNUstep2::PECOFFSectionsBaseNames[8] = 2031 { 2032 ".objcrt$SEL", 2033 ".objcrt$CLS", 2034 ".objcrt$CLR", 2035 ".objcrt$CAT", 2036 ".objcrt$PCL", 2037 ".objcrt$PCR", 2038 ".objcrt$CAL", 2039 ".objcrt$STR" 2040 }; 2041 2042 /// Support for the ObjFW runtime. 2043 class CGObjCObjFW: public CGObjCGNU { 2044 protected: 2045 /// The GCC ABI message lookup function. Returns an IMP pointing to the 2046 /// method implementation for this message. 2047 LazyRuntimeFunction MsgLookupFn; 2048 /// stret lookup function. While this does not seem to make sense at the 2049 /// first look, this is required to call the correct forwarding function. 2050 LazyRuntimeFunction MsgLookupFnSRet; 2051 /// The GCC ABI superclass message lookup function. Takes a pointer to a 2052 /// structure describing the receiver and the class, and a selector as 2053 /// arguments. Returns the IMP for the corresponding method. 2054 LazyRuntimeFunction MsgLookupSuperFn, MsgLookupSuperFnSRet; 2055 2056 llvm::Value *LookupIMP(CodeGenFunction &CGF, llvm::Value *&Receiver, 2057 llvm::Value *cmd, llvm::MDNode *node, 2058 MessageSendInfo &MSI) override { 2059 CGBuilderTy &Builder = CGF.Builder; 2060 llvm::Value *args[] = { 2061 EnforceType(Builder, Receiver, IdTy), 2062 EnforceType(Builder, cmd, SelectorTy) }; 2063 2064 llvm::CallBase *imp; 2065 if (CGM.ReturnTypeUsesSRet(MSI.CallInfo)) 2066 imp = CGF.EmitRuntimeCallOrInvoke(MsgLookupFnSRet, args); 2067 else 2068 imp = CGF.EmitRuntimeCallOrInvoke(MsgLookupFn, args); 2069 2070 imp->setMetadata(msgSendMDKind, node); 2071 return imp; 2072 } 2073 2074 llvm::Value *LookupIMPSuper(CodeGenFunction &CGF, Address ObjCSuper, 2075 llvm::Value *cmd, MessageSendInfo &MSI) override { 2076 CGBuilderTy &Builder = CGF.Builder; 2077 llvm::Value *lookupArgs[] = { 2078 EnforceType(Builder, ObjCSuper.getPointer(), PtrToObjCSuperTy), cmd, 2079 }; 2080 2081 if (CGM.ReturnTypeUsesSRet(MSI.CallInfo)) 2082 return CGF.EmitNounwindRuntimeCall(MsgLookupSuperFnSRet, lookupArgs); 2083 else 2084 return CGF.EmitNounwindRuntimeCall(MsgLookupSuperFn, lookupArgs); 2085 } 2086 2087 llvm::Value *GetClassNamed(CodeGenFunction &CGF, const std::string &Name, 2088 bool isWeak) override { 2089 if (isWeak) 2090 return CGObjCGNU::GetClassNamed(CGF, Name, isWeak); 2091 2092 EmitClassRef(Name); 2093 std::string SymbolName = "_OBJC_CLASS_" + Name; 2094 llvm::GlobalVariable *ClassSymbol = TheModule.getGlobalVariable(SymbolName); 2095 if (!ClassSymbol) 2096 ClassSymbol = new llvm::GlobalVariable(TheModule, LongTy, false, 2097 llvm::GlobalValue::ExternalLinkage, 2098 nullptr, SymbolName); 2099 return ClassSymbol; 2100 } 2101 2102 public: 2103 CGObjCObjFW(CodeGenModule &Mod): CGObjCGNU(Mod, 9, 3) { 2104 // IMP objc_msg_lookup(id, SEL); 2105 MsgLookupFn.init(&CGM, "objc_msg_lookup", IMPTy, IdTy, SelectorTy); 2106 MsgLookupFnSRet.init(&CGM, "objc_msg_lookup_stret", IMPTy, IdTy, 2107 SelectorTy); 2108 // IMP objc_msg_lookup_super(struct objc_super*, SEL); 2109 MsgLookupSuperFn.init(&CGM, "objc_msg_lookup_super", IMPTy, 2110 PtrToObjCSuperTy, SelectorTy); 2111 MsgLookupSuperFnSRet.init(&CGM, "objc_msg_lookup_super_stret", IMPTy, 2112 PtrToObjCSuperTy, SelectorTy); 2113 } 2114 }; 2115 } // end anonymous namespace 2116 2117 /// Emits a reference to a dummy variable which is emitted with each class. 2118 /// This ensures that a linker error will be generated when trying to link 2119 /// together modules where a referenced class is not defined. 2120 void CGObjCGNU::EmitClassRef(const std::string &className) { 2121 std::string symbolRef = "__objc_class_ref_" + className; 2122 // Don't emit two copies of the same symbol 2123 if (TheModule.getGlobalVariable(symbolRef)) 2124 return; 2125 std::string symbolName = "__objc_class_name_" + className; 2126 llvm::GlobalVariable *ClassSymbol = TheModule.getGlobalVariable(symbolName); 2127 if (!ClassSymbol) { 2128 ClassSymbol = new llvm::GlobalVariable(TheModule, LongTy, false, 2129 llvm::GlobalValue::ExternalLinkage, 2130 nullptr, symbolName); 2131 } 2132 new llvm::GlobalVariable(TheModule, ClassSymbol->getType(), true, 2133 llvm::GlobalValue::WeakAnyLinkage, ClassSymbol, symbolRef); 2134 } 2135 2136 CGObjCGNU::CGObjCGNU(CodeGenModule &cgm, unsigned runtimeABIVersion, 2137 unsigned protocolClassVersion, unsigned classABI) 2138 : CGObjCRuntime(cgm), TheModule(CGM.getModule()), 2139 VMContext(cgm.getLLVMContext()), ClassPtrAlias(nullptr), 2140 MetaClassPtrAlias(nullptr), RuntimeVersion(runtimeABIVersion), 2141 ProtocolVersion(protocolClassVersion), ClassABIVersion(classABI) { 2142 2143 msgSendMDKind = VMContext.getMDKindID("GNUObjCMessageSend"); 2144 usesSEHExceptions = 2145 cgm.getContext().getTargetInfo().getTriple().isWindowsMSVCEnvironment(); 2146 2147 CodeGenTypes &Types = CGM.getTypes(); 2148 IntTy = cast<llvm::IntegerType>( 2149 Types.ConvertType(CGM.getContext().IntTy)); 2150 LongTy = cast<llvm::IntegerType>( 2151 Types.ConvertType(CGM.getContext().LongTy)); 2152 SizeTy = cast<llvm::IntegerType>( 2153 Types.ConvertType(CGM.getContext().getSizeType())); 2154 PtrDiffTy = cast<llvm::IntegerType>( 2155 Types.ConvertType(CGM.getContext().getPointerDiffType())); 2156 BoolTy = CGM.getTypes().ConvertType(CGM.getContext().BoolTy); 2157 2158 Int8Ty = llvm::Type::getInt8Ty(VMContext); 2159 // C string type. Used in lots of places. 2160 PtrToInt8Ty = llvm::PointerType::getUnqual(Int8Ty); 2161 ProtocolPtrTy = llvm::PointerType::getUnqual( 2162 Types.ConvertType(CGM.getContext().getObjCProtoType())); 2163 2164 Zeros[0] = llvm::ConstantInt::get(LongTy, 0); 2165 Zeros[1] = Zeros[0]; 2166 NULLPtr = llvm::ConstantPointerNull::get(PtrToInt8Ty); 2167 // Get the selector Type. 2168 QualType selTy = CGM.getContext().getObjCSelType(); 2169 if (QualType() == selTy) { 2170 SelectorTy = PtrToInt8Ty; 2171 } else { 2172 SelectorTy = cast<llvm::PointerType>(CGM.getTypes().ConvertType(selTy)); 2173 } 2174 2175 PtrToIntTy = llvm::PointerType::getUnqual(IntTy); 2176 PtrTy = PtrToInt8Ty; 2177 2178 Int32Ty = llvm::Type::getInt32Ty(VMContext); 2179 Int64Ty = llvm::Type::getInt64Ty(VMContext); 2180 2181 IntPtrTy = 2182 CGM.getDataLayout().getPointerSizeInBits() == 32 ? Int32Ty : Int64Ty; 2183 2184 // Object type 2185 QualType UnqualIdTy = CGM.getContext().getObjCIdType(); 2186 ASTIdTy = CanQualType(); 2187 if (UnqualIdTy != QualType()) { 2188 ASTIdTy = CGM.getContext().getCanonicalType(UnqualIdTy); 2189 IdTy = cast<llvm::PointerType>(CGM.getTypes().ConvertType(ASTIdTy)); 2190 } else { 2191 IdTy = PtrToInt8Ty; 2192 } 2193 PtrToIdTy = llvm::PointerType::getUnqual(IdTy); 2194 ProtocolTy = llvm::StructType::get(IdTy, 2195 PtrToInt8Ty, // name 2196 PtrToInt8Ty, // protocols 2197 PtrToInt8Ty, // instance methods 2198 PtrToInt8Ty, // class methods 2199 PtrToInt8Ty, // optional instance methods 2200 PtrToInt8Ty, // optional class methods 2201 PtrToInt8Ty, // properties 2202 PtrToInt8Ty);// optional properties 2203 2204 // struct objc_property_gsv1 2205 // { 2206 // const char *name; 2207 // char attributes; 2208 // char attributes2; 2209 // char unused1; 2210 // char unused2; 2211 // const char *getter_name; 2212 // const char *getter_types; 2213 // const char *setter_name; 2214 // const char *setter_types; 2215 // } 2216 PropertyMetadataTy = llvm::StructType::get(CGM.getLLVMContext(), { 2217 PtrToInt8Ty, Int8Ty, Int8Ty, Int8Ty, Int8Ty, PtrToInt8Ty, PtrToInt8Ty, 2218 PtrToInt8Ty, PtrToInt8Ty }); 2219 2220 ObjCSuperTy = llvm::StructType::get(IdTy, IdTy); 2221 PtrToObjCSuperTy = llvm::PointerType::getUnqual(ObjCSuperTy); 2222 2223 llvm::Type *VoidTy = llvm::Type::getVoidTy(VMContext); 2224 2225 // void objc_exception_throw(id); 2226 ExceptionThrowFn.init(&CGM, "objc_exception_throw", VoidTy, IdTy); 2227 ExceptionReThrowFn.init(&CGM, "objc_exception_throw", VoidTy, IdTy); 2228 // int objc_sync_enter(id); 2229 SyncEnterFn.init(&CGM, "objc_sync_enter", IntTy, IdTy); 2230 // int objc_sync_exit(id); 2231 SyncExitFn.init(&CGM, "objc_sync_exit", IntTy, IdTy); 2232 2233 // void objc_enumerationMutation (id) 2234 EnumerationMutationFn.init(&CGM, "objc_enumerationMutation", VoidTy, IdTy); 2235 2236 // id objc_getProperty(id, SEL, ptrdiff_t, BOOL) 2237 GetPropertyFn.init(&CGM, "objc_getProperty", IdTy, IdTy, SelectorTy, 2238 PtrDiffTy, BoolTy); 2239 // void objc_setProperty(id, SEL, ptrdiff_t, id, BOOL, BOOL) 2240 SetPropertyFn.init(&CGM, "objc_setProperty", VoidTy, IdTy, SelectorTy, 2241 PtrDiffTy, IdTy, BoolTy, BoolTy); 2242 // void objc_setPropertyStruct(void*, void*, ptrdiff_t, BOOL, BOOL) 2243 GetStructPropertyFn.init(&CGM, "objc_getPropertyStruct", VoidTy, PtrTy, PtrTy, 2244 PtrDiffTy, BoolTy, BoolTy); 2245 // void objc_setPropertyStruct(void*, void*, ptrdiff_t, BOOL, BOOL) 2246 SetStructPropertyFn.init(&CGM, "objc_setPropertyStruct", VoidTy, PtrTy, PtrTy, 2247 PtrDiffTy, BoolTy, BoolTy); 2248 2249 // IMP type 2250 llvm::Type *IMPArgs[] = { IdTy, SelectorTy }; 2251 IMPTy = llvm::PointerType::getUnqual(llvm::FunctionType::get(IdTy, IMPArgs, 2252 true)); 2253 2254 const LangOptions &Opts = CGM.getLangOpts(); 2255 if ((Opts.getGC() != LangOptions::NonGC) || Opts.ObjCAutoRefCount) 2256 RuntimeVersion = 10; 2257 2258 // Don't bother initialising the GC stuff unless we're compiling in GC mode 2259 if (Opts.getGC() != LangOptions::NonGC) { 2260 // This is a bit of an hack. We should sort this out by having a proper 2261 // CGObjCGNUstep subclass for GC, but we may want to really support the old 2262 // ABI and GC added in ObjectiveC2.framework, so we fudge it a bit for now 2263 // Get selectors needed in GC mode 2264 RetainSel = GetNullarySelector("retain", CGM.getContext()); 2265 ReleaseSel = GetNullarySelector("release", CGM.getContext()); 2266 AutoreleaseSel = GetNullarySelector("autorelease", CGM.getContext()); 2267 2268 // Get functions needed in GC mode 2269 2270 // id objc_assign_ivar(id, id, ptrdiff_t); 2271 IvarAssignFn.init(&CGM, "objc_assign_ivar", IdTy, IdTy, IdTy, PtrDiffTy); 2272 // id objc_assign_strongCast (id, id*) 2273 StrongCastAssignFn.init(&CGM, "objc_assign_strongCast", IdTy, IdTy, 2274 PtrToIdTy); 2275 // id objc_assign_global(id, id*); 2276 GlobalAssignFn.init(&CGM, "objc_assign_global", IdTy, IdTy, PtrToIdTy); 2277 // id objc_assign_weak(id, id*); 2278 WeakAssignFn.init(&CGM, "objc_assign_weak", IdTy, IdTy, PtrToIdTy); 2279 // id objc_read_weak(id*); 2280 WeakReadFn.init(&CGM, "objc_read_weak", IdTy, PtrToIdTy); 2281 // void *objc_memmove_collectable(void*, void *, size_t); 2282 MemMoveFn.init(&CGM, "objc_memmove_collectable", PtrTy, PtrTy, PtrTy, 2283 SizeTy); 2284 } 2285 } 2286 2287 llvm::Value *CGObjCGNU::GetClassNamed(CodeGenFunction &CGF, 2288 const std::string &Name, bool isWeak) { 2289 llvm::Constant *ClassName = MakeConstantString(Name); 2290 // With the incompatible ABI, this will need to be replaced with a direct 2291 // reference to the class symbol. For the compatible nonfragile ABI we are 2292 // still performing this lookup at run time but emitting the symbol for the 2293 // class externally so that we can make the switch later. 2294 // 2295 // Libobjc2 contains an LLVM pass that replaces calls to objc_lookup_class 2296 // with memoized versions or with static references if it's safe to do so. 2297 if (!isWeak) 2298 EmitClassRef(Name); 2299 2300 llvm::FunctionCallee ClassLookupFn = CGM.CreateRuntimeFunction( 2301 llvm::FunctionType::get(IdTy, PtrToInt8Ty, true), "objc_lookup_class"); 2302 return CGF.EmitNounwindRuntimeCall(ClassLookupFn, ClassName); 2303 } 2304 2305 // This has to perform the lookup every time, since posing and related 2306 // techniques can modify the name -> class mapping. 2307 llvm::Value *CGObjCGNU::GetClass(CodeGenFunction &CGF, 2308 const ObjCInterfaceDecl *OID) { 2309 auto *Value = 2310 GetClassNamed(CGF, OID->getNameAsString(), OID->isWeakImported()); 2311 if (auto *ClassSymbol = dyn_cast<llvm::GlobalVariable>(Value)) 2312 CGM.setGVProperties(ClassSymbol, OID); 2313 return Value; 2314 } 2315 2316 llvm::Value *CGObjCGNU::EmitNSAutoreleasePoolClassRef(CodeGenFunction &CGF) { 2317 auto *Value = GetClassNamed(CGF, "NSAutoreleasePool", false); 2318 if (CGM.getTriple().isOSBinFormatCOFF()) { 2319 if (auto *ClassSymbol = dyn_cast<llvm::GlobalVariable>(Value)) { 2320 IdentifierInfo &II = CGF.CGM.getContext().Idents.get("NSAutoreleasePool"); 2321 TranslationUnitDecl *TUDecl = CGM.getContext().getTranslationUnitDecl(); 2322 DeclContext *DC = TranslationUnitDecl::castToDeclContext(TUDecl); 2323 2324 const VarDecl *VD = nullptr; 2325 for (const auto *Result : DC->lookup(&II)) 2326 if ((VD = dyn_cast<VarDecl>(Result))) 2327 break; 2328 2329 CGM.setGVProperties(ClassSymbol, VD); 2330 } 2331 } 2332 return Value; 2333 } 2334 2335 llvm::Value *CGObjCGNU::GetTypedSelector(CodeGenFunction &CGF, Selector Sel, 2336 const std::string &TypeEncoding) { 2337 SmallVectorImpl<TypedSelector> &Types = SelectorTable[Sel]; 2338 llvm::GlobalAlias *SelValue = nullptr; 2339 2340 for (SmallVectorImpl<TypedSelector>::iterator i = Types.begin(), 2341 e = Types.end() ; i!=e ; i++) { 2342 if (i->first == TypeEncoding) { 2343 SelValue = i->second; 2344 break; 2345 } 2346 } 2347 if (!SelValue) { 2348 SelValue = llvm::GlobalAlias::create( 2349 SelectorTy->getElementType(), 0, llvm::GlobalValue::PrivateLinkage, 2350 ".objc_selector_" + Sel.getAsString(), &TheModule); 2351 Types.emplace_back(TypeEncoding, SelValue); 2352 } 2353 2354 return SelValue; 2355 } 2356 2357 Address CGObjCGNU::GetAddrOfSelector(CodeGenFunction &CGF, Selector Sel) { 2358 llvm::Value *SelValue = GetSelector(CGF, Sel); 2359 2360 // Store it to a temporary. Does this satisfy the semantics of 2361 // GetAddrOfSelector? Hopefully. 2362 Address tmp = CGF.CreateTempAlloca(SelValue->getType(), 2363 CGF.getPointerAlign()); 2364 CGF.Builder.CreateStore(SelValue, tmp); 2365 return tmp; 2366 } 2367 2368 llvm::Value *CGObjCGNU::GetSelector(CodeGenFunction &CGF, Selector Sel) { 2369 return GetTypedSelector(CGF, Sel, std::string()); 2370 } 2371 2372 llvm::Value *CGObjCGNU::GetSelector(CodeGenFunction &CGF, 2373 const ObjCMethodDecl *Method) { 2374 std::string SelTypes = CGM.getContext().getObjCEncodingForMethodDecl(Method); 2375 return GetTypedSelector(CGF, Method->getSelector(), SelTypes); 2376 } 2377 2378 llvm::Constant *CGObjCGNU::GetEHType(QualType T) { 2379 if (T->isObjCIdType() || T->isObjCQualifiedIdType()) { 2380 // With the old ABI, there was only one kind of catchall, which broke 2381 // foreign exceptions. With the new ABI, we use __objc_id_typeinfo as 2382 // a pointer indicating object catchalls, and NULL to indicate real 2383 // catchalls 2384 if (CGM.getLangOpts().ObjCRuntime.isNonFragile()) { 2385 return MakeConstantString("@id"); 2386 } else { 2387 return nullptr; 2388 } 2389 } 2390 2391 // All other types should be Objective-C interface pointer types. 2392 const ObjCObjectPointerType *OPT = T->getAs<ObjCObjectPointerType>(); 2393 assert(OPT && "Invalid @catch type."); 2394 const ObjCInterfaceDecl *IDecl = OPT->getObjectType()->getInterface(); 2395 assert(IDecl && "Invalid @catch type."); 2396 return MakeConstantString(IDecl->getIdentifier()->getName()); 2397 } 2398 2399 llvm::Constant *CGObjCGNUstep::GetEHType(QualType T) { 2400 if (usesSEHExceptions) 2401 return CGM.getCXXABI().getAddrOfRTTIDescriptor(T); 2402 2403 if (!CGM.getLangOpts().CPlusPlus) 2404 return CGObjCGNU::GetEHType(T); 2405 2406 // For Objective-C++, we want to provide the ability to catch both C++ and 2407 // Objective-C objects in the same function. 2408 2409 // There's a particular fixed type info for 'id'. 2410 if (T->isObjCIdType() || 2411 T->isObjCQualifiedIdType()) { 2412 llvm::Constant *IDEHType = 2413 CGM.getModule().getGlobalVariable("__objc_id_type_info"); 2414 if (!IDEHType) 2415 IDEHType = 2416 new llvm::GlobalVariable(CGM.getModule(), PtrToInt8Ty, 2417 false, 2418 llvm::GlobalValue::ExternalLinkage, 2419 nullptr, "__objc_id_type_info"); 2420 return llvm::ConstantExpr::getBitCast(IDEHType, PtrToInt8Ty); 2421 } 2422 2423 const ObjCObjectPointerType *PT = 2424 T->getAs<ObjCObjectPointerType>(); 2425 assert(PT && "Invalid @catch type."); 2426 const ObjCInterfaceType *IT = PT->getInterfaceType(); 2427 assert(IT && "Invalid @catch type."); 2428 std::string className = 2429 std::string(IT->getDecl()->getIdentifier()->getName()); 2430 2431 std::string typeinfoName = "__objc_eh_typeinfo_" + className; 2432 2433 // Return the existing typeinfo if it exists 2434 llvm::Constant *typeinfo = TheModule.getGlobalVariable(typeinfoName); 2435 if (typeinfo) 2436 return llvm::ConstantExpr::getBitCast(typeinfo, PtrToInt8Ty); 2437 2438 // Otherwise create it. 2439 2440 // vtable for gnustep::libobjc::__objc_class_type_info 2441 // It's quite ugly hard-coding this. Ideally we'd generate it using the host 2442 // platform's name mangling. 2443 const char *vtableName = "_ZTVN7gnustep7libobjc22__objc_class_type_infoE"; 2444 auto *Vtable = TheModule.getGlobalVariable(vtableName); 2445 if (!Vtable) { 2446 Vtable = new llvm::GlobalVariable(TheModule, PtrToInt8Ty, true, 2447 llvm::GlobalValue::ExternalLinkage, 2448 nullptr, vtableName); 2449 } 2450 llvm::Constant *Two = llvm::ConstantInt::get(IntTy, 2); 2451 auto *BVtable = llvm::ConstantExpr::getBitCast( 2452 llvm::ConstantExpr::getGetElementPtr(Vtable->getValueType(), Vtable, Two), 2453 PtrToInt8Ty); 2454 2455 llvm::Constant *typeName = 2456 ExportUniqueString(className, "__objc_eh_typename_"); 2457 2458 ConstantInitBuilder builder(CGM); 2459 auto fields = builder.beginStruct(); 2460 fields.add(BVtable); 2461 fields.add(typeName); 2462 llvm::Constant *TI = 2463 fields.finishAndCreateGlobal("__objc_eh_typeinfo_" + className, 2464 CGM.getPointerAlign(), 2465 /*constant*/ false, 2466 llvm::GlobalValue::LinkOnceODRLinkage); 2467 return llvm::ConstantExpr::getBitCast(TI, PtrToInt8Ty); 2468 } 2469 2470 /// Generate an NSConstantString object. 2471 ConstantAddress CGObjCGNU::GenerateConstantString(const StringLiteral *SL) { 2472 2473 std::string Str = SL->getString().str(); 2474 CharUnits Align = CGM.getPointerAlign(); 2475 2476 // Look for an existing one 2477 llvm::StringMap<llvm::Constant*>::iterator old = ObjCStrings.find(Str); 2478 if (old != ObjCStrings.end()) 2479 return ConstantAddress(old->getValue(), Align); 2480 2481 StringRef StringClass = CGM.getLangOpts().ObjCConstantStringClass; 2482 2483 if (StringClass.empty()) StringClass = "NSConstantString"; 2484 2485 std::string Sym = "_OBJC_CLASS_"; 2486 Sym += StringClass; 2487 2488 llvm::Constant *isa = TheModule.getNamedGlobal(Sym); 2489 2490 if (!isa) 2491 isa = new llvm::GlobalVariable(TheModule, IdTy, /* isConstant */false, 2492 llvm::GlobalValue::ExternalWeakLinkage, nullptr, Sym); 2493 else if (isa->getType() != PtrToIdTy) 2494 isa = llvm::ConstantExpr::getBitCast(isa, PtrToIdTy); 2495 2496 ConstantInitBuilder Builder(CGM); 2497 auto Fields = Builder.beginStruct(); 2498 Fields.add(isa); 2499 Fields.add(MakeConstantString(Str)); 2500 Fields.addInt(IntTy, Str.size()); 2501 llvm::Constant *ObjCStr = 2502 Fields.finishAndCreateGlobal(".objc_str", Align); 2503 ObjCStr = llvm::ConstantExpr::getBitCast(ObjCStr, PtrToInt8Ty); 2504 ObjCStrings[Str] = ObjCStr; 2505 ConstantStrings.push_back(ObjCStr); 2506 return ConstantAddress(ObjCStr, Align); 2507 } 2508 2509 ///Generates a message send where the super is the receiver. This is a message 2510 ///send to self with special delivery semantics indicating which class's method 2511 ///should be called. 2512 RValue 2513 CGObjCGNU::GenerateMessageSendSuper(CodeGenFunction &CGF, 2514 ReturnValueSlot Return, 2515 QualType ResultType, 2516 Selector Sel, 2517 const ObjCInterfaceDecl *Class, 2518 bool isCategoryImpl, 2519 llvm::Value *Receiver, 2520 bool IsClassMessage, 2521 const CallArgList &CallArgs, 2522 const ObjCMethodDecl *Method) { 2523 CGBuilderTy &Builder = CGF.Builder; 2524 if (CGM.getLangOpts().getGC() == LangOptions::GCOnly) { 2525 if (Sel == RetainSel || Sel == AutoreleaseSel) { 2526 return RValue::get(EnforceType(Builder, Receiver, 2527 CGM.getTypes().ConvertType(ResultType))); 2528 } 2529 if (Sel == ReleaseSel) { 2530 return RValue::get(nullptr); 2531 } 2532 } 2533 2534 llvm::Value *cmd = GetSelector(CGF, Sel); 2535 CallArgList ActualArgs; 2536 2537 ActualArgs.add(RValue::get(EnforceType(Builder, Receiver, IdTy)), ASTIdTy); 2538 ActualArgs.add(RValue::get(cmd), CGF.getContext().getObjCSelType()); 2539 ActualArgs.addFrom(CallArgs); 2540 2541 MessageSendInfo MSI = getMessageSendInfo(Method, ResultType, ActualArgs); 2542 2543 llvm::Value *ReceiverClass = nullptr; 2544 bool isV2ABI = isRuntime(ObjCRuntime::GNUstep, 2); 2545 if (isV2ABI) { 2546 ReceiverClass = GetClassNamed(CGF, 2547 Class->getSuperClass()->getNameAsString(), /*isWeak*/false); 2548 if (IsClassMessage) { 2549 // Load the isa pointer of the superclass is this is a class method. 2550 ReceiverClass = Builder.CreateBitCast(ReceiverClass, 2551 llvm::PointerType::getUnqual(IdTy)); 2552 ReceiverClass = 2553 Builder.CreateAlignedLoad(IdTy, ReceiverClass, CGF.getPointerAlign()); 2554 } 2555 ReceiverClass = EnforceType(Builder, ReceiverClass, IdTy); 2556 } else { 2557 if (isCategoryImpl) { 2558 llvm::FunctionCallee classLookupFunction = nullptr; 2559 if (IsClassMessage) { 2560 classLookupFunction = CGM.CreateRuntimeFunction(llvm::FunctionType::get( 2561 IdTy, PtrTy, true), "objc_get_meta_class"); 2562 } else { 2563 classLookupFunction = CGM.CreateRuntimeFunction(llvm::FunctionType::get( 2564 IdTy, PtrTy, true), "objc_get_class"); 2565 } 2566 ReceiverClass = Builder.CreateCall(classLookupFunction, 2567 MakeConstantString(Class->getNameAsString())); 2568 } else { 2569 // Set up global aliases for the metaclass or class pointer if they do not 2570 // already exist. These will are forward-references which will be set to 2571 // pointers to the class and metaclass structure created for the runtime 2572 // load function. To send a message to super, we look up the value of the 2573 // super_class pointer from either the class or metaclass structure. 2574 if (IsClassMessage) { 2575 if (!MetaClassPtrAlias) { 2576 MetaClassPtrAlias = llvm::GlobalAlias::create( 2577 IdTy->getElementType(), 0, llvm::GlobalValue::InternalLinkage, 2578 ".objc_metaclass_ref" + Class->getNameAsString(), &TheModule); 2579 } 2580 ReceiverClass = MetaClassPtrAlias; 2581 } else { 2582 if (!ClassPtrAlias) { 2583 ClassPtrAlias = llvm::GlobalAlias::create( 2584 IdTy->getElementType(), 0, llvm::GlobalValue::InternalLinkage, 2585 ".objc_class_ref" + Class->getNameAsString(), &TheModule); 2586 } 2587 ReceiverClass = ClassPtrAlias; 2588 } 2589 } 2590 // Cast the pointer to a simplified version of the class structure 2591 llvm::Type *CastTy = llvm::StructType::get(IdTy, IdTy); 2592 ReceiverClass = Builder.CreateBitCast(ReceiverClass, 2593 llvm::PointerType::getUnqual(CastTy)); 2594 // Get the superclass pointer 2595 ReceiverClass = Builder.CreateStructGEP(CastTy, ReceiverClass, 1); 2596 // Load the superclass pointer 2597 ReceiverClass = 2598 Builder.CreateAlignedLoad(IdTy, ReceiverClass, CGF.getPointerAlign()); 2599 } 2600 // Construct the structure used to look up the IMP 2601 llvm::StructType *ObjCSuperTy = 2602 llvm::StructType::get(Receiver->getType(), IdTy); 2603 2604 Address ObjCSuper = CGF.CreateTempAlloca(ObjCSuperTy, 2605 CGF.getPointerAlign()); 2606 2607 Builder.CreateStore(Receiver, Builder.CreateStructGEP(ObjCSuper, 0)); 2608 Builder.CreateStore(ReceiverClass, Builder.CreateStructGEP(ObjCSuper, 1)); 2609 2610 ObjCSuper = EnforceType(Builder, ObjCSuper, PtrToObjCSuperTy); 2611 2612 // Get the IMP 2613 llvm::Value *imp = LookupIMPSuper(CGF, ObjCSuper, cmd, MSI); 2614 imp = EnforceType(Builder, imp, MSI.MessengerType); 2615 2616 llvm::Metadata *impMD[] = { 2617 llvm::MDString::get(VMContext, Sel.getAsString()), 2618 llvm::MDString::get(VMContext, Class->getSuperClass()->getNameAsString()), 2619 llvm::ConstantAsMetadata::get(llvm::ConstantInt::get( 2620 llvm::Type::getInt1Ty(VMContext), IsClassMessage))}; 2621 llvm::MDNode *node = llvm::MDNode::get(VMContext, impMD); 2622 2623 CGCallee callee(CGCalleeInfo(), imp); 2624 2625 llvm::CallBase *call; 2626 RValue msgRet = CGF.EmitCall(MSI.CallInfo, callee, Return, ActualArgs, &call); 2627 call->setMetadata(msgSendMDKind, node); 2628 return msgRet; 2629 } 2630 2631 /// Generate code for a message send expression. 2632 RValue 2633 CGObjCGNU::GenerateMessageSend(CodeGenFunction &CGF, 2634 ReturnValueSlot Return, 2635 QualType ResultType, 2636 Selector Sel, 2637 llvm::Value *Receiver, 2638 const CallArgList &CallArgs, 2639 const ObjCInterfaceDecl *Class, 2640 const ObjCMethodDecl *Method) { 2641 CGBuilderTy &Builder = CGF.Builder; 2642 2643 // Strip out message sends to retain / release in GC mode 2644 if (CGM.getLangOpts().getGC() == LangOptions::GCOnly) { 2645 if (Sel == RetainSel || Sel == AutoreleaseSel) { 2646 return RValue::get(EnforceType(Builder, Receiver, 2647 CGM.getTypes().ConvertType(ResultType))); 2648 } 2649 if (Sel == ReleaseSel) { 2650 return RValue::get(nullptr); 2651 } 2652 } 2653 2654 IdTy = cast<llvm::PointerType>(CGM.getTypes().ConvertType(ASTIdTy)); 2655 llvm::Value *cmd; 2656 if (Method) 2657 cmd = GetSelector(CGF, Method); 2658 else 2659 cmd = GetSelector(CGF, Sel); 2660 cmd = EnforceType(Builder, cmd, SelectorTy); 2661 Receiver = EnforceType(Builder, Receiver, IdTy); 2662 2663 llvm::Metadata *impMD[] = { 2664 llvm::MDString::get(VMContext, Sel.getAsString()), 2665 llvm::MDString::get(VMContext, Class ? Class->getNameAsString() : ""), 2666 llvm::ConstantAsMetadata::get(llvm::ConstantInt::get( 2667 llvm::Type::getInt1Ty(VMContext), Class != nullptr))}; 2668 llvm::MDNode *node = llvm::MDNode::get(VMContext, impMD); 2669 2670 CallArgList ActualArgs; 2671 ActualArgs.add(RValue::get(Receiver), ASTIdTy); 2672 ActualArgs.add(RValue::get(cmd), CGF.getContext().getObjCSelType()); 2673 ActualArgs.addFrom(CallArgs); 2674 2675 MessageSendInfo MSI = getMessageSendInfo(Method, ResultType, ActualArgs); 2676 2677 // Message sends are expected to return a zero value when the 2678 // receiver is nil. At one point, this was only guaranteed for 2679 // simple integer and pointer types, but expectations have grown 2680 // over time. 2681 // 2682 // Given a nil receiver, the GNU runtime's message lookup will 2683 // return a stub function that simply sets various return-value 2684 // registers to zero and then returns. That's good enough for us 2685 // if and only if (1) the calling conventions of that stub are 2686 // compatible with the signature we're using and (2) the registers 2687 // it sets are sufficient to produce a zero value of the return type. 2688 // Rather than doing a whole target-specific analysis, we assume it 2689 // only works for void, integer, and pointer types, and in all 2690 // other cases we do an explicit nil check is emitted code. In 2691 // addition to ensuring we produe a zero value for other types, this 2692 // sidesteps the few outright CC incompatibilities we know about that 2693 // could otherwise lead to crashes, like when a method is expected to 2694 // return on the x87 floating point stack or adjust the stack pointer 2695 // because of an indirect return. 2696 bool hasParamDestroyedInCallee = false; 2697 bool requiresExplicitZeroResult = false; 2698 bool requiresNilReceiverCheck = [&] { 2699 // We never need a check if we statically know the receiver isn't nil. 2700 if (!canMessageReceiverBeNull(CGF, Method, /*IsSuper*/ false, 2701 Class, Receiver)) 2702 return false; 2703 2704 // If there's a consumed argument, we need a nil check. 2705 if (Method && Method->hasParamDestroyedInCallee()) { 2706 hasParamDestroyedInCallee = true; 2707 } 2708 2709 // If the return value isn't flagged as unused, and the result 2710 // type isn't in our narrow set where we assume compatibility, 2711 // we need a nil check to ensure a nil value. 2712 if (!Return.isUnused()) { 2713 if (ResultType->isVoidType()) { 2714 // void results are definitely okay. 2715 } else if (ResultType->hasPointerRepresentation() && 2716 CGM.getTypes().isZeroInitializable(ResultType)) { 2717 // Pointer types should be fine as long as they have 2718 // bitwise-zero null pointers. But do we need to worry 2719 // about unusual address spaces? 2720 } else if (ResultType->isIntegralOrEnumerationType()) { 2721 // Bitwise zero should always be zero for integral types. 2722 // FIXME: we probably need a size limit here, but we've 2723 // never imposed one before 2724 } else { 2725 // Otherwise, use an explicit check just to be sure. 2726 requiresExplicitZeroResult = true; 2727 } 2728 } 2729 2730 return hasParamDestroyedInCallee || requiresExplicitZeroResult; 2731 }(); 2732 2733 // We will need to explicitly zero-initialize an aggregate result slot 2734 // if we generally require explicit zeroing and we have an aggregate 2735 // result. 2736 bool requiresExplicitAggZeroing = 2737 requiresExplicitZeroResult && CGF.hasAggregateEvaluationKind(ResultType); 2738 2739 // The block we're going to end up in after any message send or nil path. 2740 llvm::BasicBlock *continueBB = nullptr; 2741 // The block that eventually branched to continueBB along the nil path. 2742 llvm::BasicBlock *nilPathBB = nullptr; 2743 // The block to do explicit work in along the nil path, if necessary. 2744 llvm::BasicBlock *nilCleanupBB = nullptr; 2745 2746 // Emit the nil-receiver check. 2747 if (requiresNilReceiverCheck) { 2748 llvm::BasicBlock *messageBB = CGF.createBasicBlock("msgSend"); 2749 continueBB = CGF.createBasicBlock("continue"); 2750 2751 // If we need to zero-initialize an aggregate result or destroy 2752 // consumed arguments, we'll need a separate cleanup block. 2753 // Otherwise we can just branch directly to the continuation block. 2754 if (requiresExplicitAggZeroing || hasParamDestroyedInCallee) { 2755 nilCleanupBB = CGF.createBasicBlock("nilReceiverCleanup"); 2756 } else { 2757 nilPathBB = Builder.GetInsertBlock(); 2758 } 2759 2760 llvm::Value *isNil = Builder.CreateICmpEQ(Receiver, 2761 llvm::Constant::getNullValue(Receiver->getType())); 2762 Builder.CreateCondBr(isNil, nilCleanupBB ? nilCleanupBB : continueBB, 2763 messageBB); 2764 CGF.EmitBlock(messageBB); 2765 } 2766 2767 // Get the IMP to call 2768 llvm::Value *imp; 2769 2770 // If we have non-legacy dispatch specified, we try using the objc_msgSend() 2771 // functions. These are not supported on all platforms (or all runtimes on a 2772 // given platform), so we 2773 switch (CGM.getCodeGenOpts().getObjCDispatchMethod()) { 2774 case CodeGenOptions::Legacy: 2775 imp = LookupIMP(CGF, Receiver, cmd, node, MSI); 2776 break; 2777 case CodeGenOptions::Mixed: 2778 case CodeGenOptions::NonLegacy: 2779 if (CGM.ReturnTypeUsesFPRet(ResultType)) { 2780 imp = 2781 CGM.CreateRuntimeFunction(llvm::FunctionType::get(IdTy, IdTy, true), 2782 "objc_msgSend_fpret") 2783 .getCallee(); 2784 } else if (CGM.ReturnTypeUsesSRet(MSI.CallInfo)) { 2785 // The actual types here don't matter - we're going to bitcast the 2786 // function anyway 2787 imp = 2788 CGM.CreateRuntimeFunction(llvm::FunctionType::get(IdTy, IdTy, true), 2789 "objc_msgSend_stret") 2790 .getCallee(); 2791 } else { 2792 imp = CGM.CreateRuntimeFunction( 2793 llvm::FunctionType::get(IdTy, IdTy, true), "objc_msgSend") 2794 .getCallee(); 2795 } 2796 } 2797 2798 // Reset the receiver in case the lookup modified it 2799 ActualArgs[0] = CallArg(RValue::get(Receiver), ASTIdTy); 2800 2801 imp = EnforceType(Builder, imp, MSI.MessengerType); 2802 2803 llvm::CallBase *call; 2804 CGCallee callee(CGCalleeInfo(), imp); 2805 RValue msgRet = CGF.EmitCall(MSI.CallInfo, callee, Return, ActualArgs, &call); 2806 call->setMetadata(msgSendMDKind, node); 2807 2808 if (requiresNilReceiverCheck) { 2809 llvm::BasicBlock *nonNilPathBB = CGF.Builder.GetInsertBlock(); 2810 CGF.Builder.CreateBr(continueBB); 2811 2812 // Emit the nil path if we decided it was necessary above. 2813 if (nilCleanupBB) { 2814 CGF.EmitBlock(nilCleanupBB); 2815 2816 if (hasParamDestroyedInCallee) { 2817 destroyCalleeDestroyedArguments(CGF, Method, CallArgs); 2818 } 2819 2820 if (requiresExplicitAggZeroing) { 2821 assert(msgRet.isAggregate()); 2822 Address addr = msgRet.getAggregateAddress(); 2823 CGF.EmitNullInitialization(addr, ResultType); 2824 } 2825 2826 nilPathBB = CGF.Builder.GetInsertBlock(); 2827 CGF.Builder.CreateBr(continueBB); 2828 } 2829 2830 // Enter the continuation block and emit a phi if required. 2831 CGF.EmitBlock(continueBB); 2832 if (msgRet.isScalar()) { 2833 llvm::Value *v = msgRet.getScalarVal(); 2834 llvm::PHINode *phi = Builder.CreatePHI(v->getType(), 2); 2835 phi->addIncoming(v, nonNilPathBB); 2836 phi->addIncoming(CGM.EmitNullConstant(ResultType), nilPathBB); 2837 msgRet = RValue::get(phi); 2838 } else if (msgRet.isAggregate()) { 2839 // Aggregate zeroing is handled in nilCleanupBB when it's required. 2840 } else /* isComplex() */ { 2841 std::pair<llvm::Value*,llvm::Value*> v = msgRet.getComplexVal(); 2842 llvm::PHINode *phi = Builder.CreatePHI(v.first->getType(), 2); 2843 phi->addIncoming(v.first, nonNilPathBB); 2844 phi->addIncoming(llvm::Constant::getNullValue(v.first->getType()), 2845 nilPathBB); 2846 llvm::PHINode *phi2 = Builder.CreatePHI(v.second->getType(), 2); 2847 phi2->addIncoming(v.second, nonNilPathBB); 2848 phi2->addIncoming(llvm::Constant::getNullValue(v.second->getType()), 2849 nilPathBB); 2850 msgRet = RValue::getComplex(phi, phi2); 2851 } 2852 } 2853 return msgRet; 2854 } 2855 2856 /// Generates a MethodList. Used in construction of a objc_class and 2857 /// objc_category structures. 2858 llvm::Constant *CGObjCGNU:: 2859 GenerateMethodList(StringRef ClassName, 2860 StringRef CategoryName, 2861 ArrayRef<const ObjCMethodDecl*> Methods, 2862 bool isClassMethodList) { 2863 if (Methods.empty()) 2864 return NULLPtr; 2865 2866 ConstantInitBuilder Builder(CGM); 2867 2868 auto MethodList = Builder.beginStruct(); 2869 MethodList.addNullPointer(CGM.Int8PtrTy); 2870 MethodList.addInt(Int32Ty, Methods.size()); 2871 2872 // Get the method structure type. 2873 llvm::StructType *ObjCMethodTy = 2874 llvm::StructType::get(CGM.getLLVMContext(), { 2875 PtrToInt8Ty, // Really a selector, but the runtime creates it us. 2876 PtrToInt8Ty, // Method types 2877 IMPTy // Method pointer 2878 }); 2879 bool isV2ABI = isRuntime(ObjCRuntime::GNUstep, 2); 2880 if (isV2ABI) { 2881 // size_t size; 2882 llvm::DataLayout td(&TheModule); 2883 MethodList.addInt(SizeTy, td.getTypeSizeInBits(ObjCMethodTy) / 2884 CGM.getContext().getCharWidth()); 2885 ObjCMethodTy = 2886 llvm::StructType::get(CGM.getLLVMContext(), { 2887 IMPTy, // Method pointer 2888 PtrToInt8Ty, // Selector 2889 PtrToInt8Ty // Extended type encoding 2890 }); 2891 } else { 2892 ObjCMethodTy = 2893 llvm::StructType::get(CGM.getLLVMContext(), { 2894 PtrToInt8Ty, // Really a selector, but the runtime creates it us. 2895 PtrToInt8Ty, // Method types 2896 IMPTy // Method pointer 2897 }); 2898 } 2899 auto MethodArray = MethodList.beginArray(); 2900 ASTContext &Context = CGM.getContext(); 2901 for (const auto *OMD : Methods) { 2902 llvm::Constant *FnPtr = 2903 TheModule.getFunction(getSymbolNameForMethod(OMD)); 2904 assert(FnPtr && "Can't generate metadata for method that doesn't exist"); 2905 auto Method = MethodArray.beginStruct(ObjCMethodTy); 2906 if (isV2ABI) { 2907 Method.addBitCast(FnPtr, IMPTy); 2908 Method.add(GetConstantSelector(OMD->getSelector(), 2909 Context.getObjCEncodingForMethodDecl(OMD))); 2910 Method.add(MakeConstantString(Context.getObjCEncodingForMethodDecl(OMD, true))); 2911 } else { 2912 Method.add(MakeConstantString(OMD->getSelector().getAsString())); 2913 Method.add(MakeConstantString(Context.getObjCEncodingForMethodDecl(OMD))); 2914 Method.addBitCast(FnPtr, IMPTy); 2915 } 2916 Method.finishAndAddTo(MethodArray); 2917 } 2918 MethodArray.finishAndAddTo(MethodList); 2919 2920 // Create an instance of the structure 2921 return MethodList.finishAndCreateGlobal(".objc_method_list", 2922 CGM.getPointerAlign()); 2923 } 2924 2925 /// Generates an IvarList. Used in construction of a objc_class. 2926 llvm::Constant *CGObjCGNU:: 2927 GenerateIvarList(ArrayRef<llvm::Constant *> IvarNames, 2928 ArrayRef<llvm::Constant *> IvarTypes, 2929 ArrayRef<llvm::Constant *> IvarOffsets, 2930 ArrayRef<llvm::Constant *> IvarAlign, 2931 ArrayRef<Qualifiers::ObjCLifetime> IvarOwnership) { 2932 if (IvarNames.empty()) 2933 return NULLPtr; 2934 2935 ConstantInitBuilder Builder(CGM); 2936 2937 // Structure containing array count followed by array. 2938 auto IvarList = Builder.beginStruct(); 2939 IvarList.addInt(IntTy, (int)IvarNames.size()); 2940 2941 // Get the ivar structure type. 2942 llvm::StructType *ObjCIvarTy = 2943 llvm::StructType::get(PtrToInt8Ty, PtrToInt8Ty, IntTy); 2944 2945 // Array of ivar structures. 2946 auto Ivars = IvarList.beginArray(ObjCIvarTy); 2947 for (unsigned int i = 0, e = IvarNames.size() ; i < e ; i++) { 2948 auto Ivar = Ivars.beginStruct(ObjCIvarTy); 2949 Ivar.add(IvarNames[i]); 2950 Ivar.add(IvarTypes[i]); 2951 Ivar.add(IvarOffsets[i]); 2952 Ivar.finishAndAddTo(Ivars); 2953 } 2954 Ivars.finishAndAddTo(IvarList); 2955 2956 // Create an instance of the structure 2957 return IvarList.finishAndCreateGlobal(".objc_ivar_list", 2958 CGM.getPointerAlign()); 2959 } 2960 2961 /// Generate a class structure 2962 llvm::Constant *CGObjCGNU::GenerateClassStructure( 2963 llvm::Constant *MetaClass, 2964 llvm::Constant *SuperClass, 2965 unsigned info, 2966 const char *Name, 2967 llvm::Constant *Version, 2968 llvm::Constant *InstanceSize, 2969 llvm::Constant *IVars, 2970 llvm::Constant *Methods, 2971 llvm::Constant *Protocols, 2972 llvm::Constant *IvarOffsets, 2973 llvm::Constant *Properties, 2974 llvm::Constant *StrongIvarBitmap, 2975 llvm::Constant *WeakIvarBitmap, 2976 bool isMeta) { 2977 // Set up the class structure 2978 // Note: Several of these are char*s when they should be ids. This is 2979 // because the runtime performs this translation on load. 2980 // 2981 // Fields marked New ABI are part of the GNUstep runtime. We emit them 2982 // anyway; the classes will still work with the GNU runtime, they will just 2983 // be ignored. 2984 llvm::StructType *ClassTy = llvm::StructType::get( 2985 PtrToInt8Ty, // isa 2986 PtrToInt8Ty, // super_class 2987 PtrToInt8Ty, // name 2988 LongTy, // version 2989 LongTy, // info 2990 LongTy, // instance_size 2991 IVars->getType(), // ivars 2992 Methods->getType(), // methods 2993 // These are all filled in by the runtime, so we pretend 2994 PtrTy, // dtable 2995 PtrTy, // subclass_list 2996 PtrTy, // sibling_class 2997 PtrTy, // protocols 2998 PtrTy, // gc_object_type 2999 // New ABI: 3000 LongTy, // abi_version 3001 IvarOffsets->getType(), // ivar_offsets 3002 Properties->getType(), // properties 3003 IntPtrTy, // strong_pointers 3004 IntPtrTy // weak_pointers 3005 ); 3006 3007 ConstantInitBuilder Builder(CGM); 3008 auto Elements = Builder.beginStruct(ClassTy); 3009 3010 // Fill in the structure 3011 3012 // isa 3013 Elements.addBitCast(MetaClass, PtrToInt8Ty); 3014 // super_class 3015 Elements.add(SuperClass); 3016 // name 3017 Elements.add(MakeConstantString(Name, ".class_name")); 3018 // version 3019 Elements.addInt(LongTy, 0); 3020 // info 3021 Elements.addInt(LongTy, info); 3022 // instance_size 3023 if (isMeta) { 3024 llvm::DataLayout td(&TheModule); 3025 Elements.addInt(LongTy, 3026 td.getTypeSizeInBits(ClassTy) / 3027 CGM.getContext().getCharWidth()); 3028 } else 3029 Elements.add(InstanceSize); 3030 // ivars 3031 Elements.add(IVars); 3032 // methods 3033 Elements.add(Methods); 3034 // These are all filled in by the runtime, so we pretend 3035 // dtable 3036 Elements.add(NULLPtr); 3037 // subclass_list 3038 Elements.add(NULLPtr); 3039 // sibling_class 3040 Elements.add(NULLPtr); 3041 // protocols 3042 Elements.addBitCast(Protocols, PtrTy); 3043 // gc_object_type 3044 Elements.add(NULLPtr); 3045 // abi_version 3046 Elements.addInt(LongTy, ClassABIVersion); 3047 // ivar_offsets 3048 Elements.add(IvarOffsets); 3049 // properties 3050 Elements.add(Properties); 3051 // strong_pointers 3052 Elements.add(StrongIvarBitmap); 3053 // weak_pointers 3054 Elements.add(WeakIvarBitmap); 3055 // Create an instance of the structure 3056 // This is now an externally visible symbol, so that we can speed up class 3057 // messages in the next ABI. We may already have some weak references to 3058 // this, so check and fix them properly. 3059 std::string ClassSym((isMeta ? "_OBJC_METACLASS_": "_OBJC_CLASS_") + 3060 std::string(Name)); 3061 llvm::GlobalVariable *ClassRef = TheModule.getNamedGlobal(ClassSym); 3062 llvm::Constant *Class = 3063 Elements.finishAndCreateGlobal(ClassSym, CGM.getPointerAlign(), false, 3064 llvm::GlobalValue::ExternalLinkage); 3065 if (ClassRef) { 3066 ClassRef->replaceAllUsesWith(llvm::ConstantExpr::getBitCast(Class, 3067 ClassRef->getType())); 3068 ClassRef->removeFromParent(); 3069 Class->setName(ClassSym); 3070 } 3071 return Class; 3072 } 3073 3074 llvm::Constant *CGObjCGNU:: 3075 GenerateProtocolMethodList(ArrayRef<const ObjCMethodDecl*> Methods) { 3076 // Get the method structure type. 3077 llvm::StructType *ObjCMethodDescTy = 3078 llvm::StructType::get(CGM.getLLVMContext(), { PtrToInt8Ty, PtrToInt8Ty }); 3079 ASTContext &Context = CGM.getContext(); 3080 ConstantInitBuilder Builder(CGM); 3081 auto MethodList = Builder.beginStruct(); 3082 MethodList.addInt(IntTy, Methods.size()); 3083 auto MethodArray = MethodList.beginArray(ObjCMethodDescTy); 3084 for (auto *M : Methods) { 3085 auto Method = MethodArray.beginStruct(ObjCMethodDescTy); 3086 Method.add(MakeConstantString(M->getSelector().getAsString())); 3087 Method.add(MakeConstantString(Context.getObjCEncodingForMethodDecl(M))); 3088 Method.finishAndAddTo(MethodArray); 3089 } 3090 MethodArray.finishAndAddTo(MethodList); 3091 return MethodList.finishAndCreateGlobal(".objc_method_list", 3092 CGM.getPointerAlign()); 3093 } 3094 3095 // Create the protocol list structure used in classes, categories and so on 3096 llvm::Constant * 3097 CGObjCGNU::GenerateProtocolList(ArrayRef<std::string> Protocols) { 3098 3099 ConstantInitBuilder Builder(CGM); 3100 auto ProtocolList = Builder.beginStruct(); 3101 ProtocolList.add(NULLPtr); 3102 ProtocolList.addInt(LongTy, Protocols.size()); 3103 3104 auto Elements = ProtocolList.beginArray(PtrToInt8Ty); 3105 for (const std::string *iter = Protocols.begin(), *endIter = Protocols.end(); 3106 iter != endIter ; iter++) { 3107 llvm::Constant *protocol = nullptr; 3108 llvm::StringMap<llvm::Constant*>::iterator value = 3109 ExistingProtocols.find(*iter); 3110 if (value == ExistingProtocols.end()) { 3111 protocol = GenerateEmptyProtocol(*iter); 3112 } else { 3113 protocol = value->getValue(); 3114 } 3115 Elements.addBitCast(protocol, PtrToInt8Ty); 3116 } 3117 Elements.finishAndAddTo(ProtocolList); 3118 return ProtocolList.finishAndCreateGlobal(".objc_protocol_list", 3119 CGM.getPointerAlign()); 3120 } 3121 3122 llvm::Value *CGObjCGNU::GenerateProtocolRef(CodeGenFunction &CGF, 3123 const ObjCProtocolDecl *PD) { 3124 auto protocol = GenerateProtocolRef(PD); 3125 llvm::Type *T = 3126 CGM.getTypes().ConvertType(CGM.getContext().getObjCProtoType()); 3127 return CGF.Builder.CreateBitCast(protocol, llvm::PointerType::getUnqual(T)); 3128 } 3129 3130 llvm::Constant *CGObjCGNU::GenerateProtocolRef(const ObjCProtocolDecl *PD) { 3131 llvm::Constant *&protocol = ExistingProtocols[PD->getNameAsString()]; 3132 if (!protocol) 3133 GenerateProtocol(PD); 3134 assert(protocol && "Unknown protocol"); 3135 return protocol; 3136 } 3137 3138 llvm::Constant * 3139 CGObjCGNU::GenerateEmptyProtocol(StringRef ProtocolName) { 3140 llvm::Constant *ProtocolList = GenerateProtocolList({}); 3141 llvm::Constant *MethodList = GenerateProtocolMethodList({}); 3142 MethodList = llvm::ConstantExpr::getBitCast(MethodList, PtrToInt8Ty); 3143 // Protocols are objects containing lists of the methods implemented and 3144 // protocols adopted. 3145 ConstantInitBuilder Builder(CGM); 3146 auto Elements = Builder.beginStruct(); 3147 3148 // The isa pointer must be set to a magic number so the runtime knows it's 3149 // the correct layout. 3150 Elements.add(llvm::ConstantExpr::getIntToPtr( 3151 llvm::ConstantInt::get(Int32Ty, ProtocolVersion), IdTy)); 3152 3153 Elements.add(MakeConstantString(ProtocolName, ".objc_protocol_name")); 3154 Elements.add(ProtocolList); /* .protocol_list */ 3155 Elements.add(MethodList); /* .instance_methods */ 3156 Elements.add(MethodList); /* .class_methods */ 3157 Elements.add(MethodList); /* .optional_instance_methods */ 3158 Elements.add(MethodList); /* .optional_class_methods */ 3159 Elements.add(NULLPtr); /* .properties */ 3160 Elements.add(NULLPtr); /* .optional_properties */ 3161 return Elements.finishAndCreateGlobal(SymbolForProtocol(ProtocolName), 3162 CGM.getPointerAlign()); 3163 } 3164 3165 void CGObjCGNU::GenerateProtocol(const ObjCProtocolDecl *PD) { 3166 if (PD->isNonRuntimeProtocol()) 3167 return; 3168 3169 std::string ProtocolName = PD->getNameAsString(); 3170 3171 // Use the protocol definition, if there is one. 3172 if (const ObjCProtocolDecl *Def = PD->getDefinition()) 3173 PD = Def; 3174 3175 SmallVector<std::string, 16> Protocols; 3176 for (const auto *PI : PD->protocols()) 3177 Protocols.push_back(PI->getNameAsString()); 3178 SmallVector<const ObjCMethodDecl*, 16> InstanceMethods; 3179 SmallVector<const ObjCMethodDecl*, 16> OptionalInstanceMethods; 3180 for (const auto *I : PD->instance_methods()) 3181 if (I->isOptional()) 3182 OptionalInstanceMethods.push_back(I); 3183 else 3184 InstanceMethods.push_back(I); 3185 // Collect information about class methods: 3186 SmallVector<const ObjCMethodDecl*, 16> ClassMethods; 3187 SmallVector<const ObjCMethodDecl*, 16> OptionalClassMethods; 3188 for (const auto *I : PD->class_methods()) 3189 if (I->isOptional()) 3190 OptionalClassMethods.push_back(I); 3191 else 3192 ClassMethods.push_back(I); 3193 3194 llvm::Constant *ProtocolList = GenerateProtocolList(Protocols); 3195 llvm::Constant *InstanceMethodList = 3196 GenerateProtocolMethodList(InstanceMethods); 3197 llvm::Constant *ClassMethodList = 3198 GenerateProtocolMethodList(ClassMethods); 3199 llvm::Constant *OptionalInstanceMethodList = 3200 GenerateProtocolMethodList(OptionalInstanceMethods); 3201 llvm::Constant *OptionalClassMethodList = 3202 GenerateProtocolMethodList(OptionalClassMethods); 3203 3204 // Property metadata: name, attributes, isSynthesized, setter name, setter 3205 // types, getter name, getter types. 3206 // The isSynthesized value is always set to 0 in a protocol. It exists to 3207 // simplify the runtime library by allowing it to use the same data 3208 // structures for protocol metadata everywhere. 3209 3210 llvm::Constant *PropertyList = 3211 GeneratePropertyList(nullptr, PD, false, false); 3212 llvm::Constant *OptionalPropertyList = 3213 GeneratePropertyList(nullptr, PD, false, true); 3214 3215 // Protocols are objects containing lists of the methods implemented and 3216 // protocols adopted. 3217 // The isa pointer must be set to a magic number so the runtime knows it's 3218 // the correct layout. 3219 ConstantInitBuilder Builder(CGM); 3220 auto Elements = Builder.beginStruct(); 3221 Elements.add( 3222 llvm::ConstantExpr::getIntToPtr( 3223 llvm::ConstantInt::get(Int32Ty, ProtocolVersion), IdTy)); 3224 Elements.add(MakeConstantString(ProtocolName)); 3225 Elements.add(ProtocolList); 3226 Elements.add(InstanceMethodList); 3227 Elements.add(ClassMethodList); 3228 Elements.add(OptionalInstanceMethodList); 3229 Elements.add(OptionalClassMethodList); 3230 Elements.add(PropertyList); 3231 Elements.add(OptionalPropertyList); 3232 ExistingProtocols[ProtocolName] = 3233 llvm::ConstantExpr::getBitCast( 3234 Elements.finishAndCreateGlobal(".objc_protocol", CGM.getPointerAlign()), 3235 IdTy); 3236 } 3237 void CGObjCGNU::GenerateProtocolHolderCategory() { 3238 // Collect information about instance methods 3239 3240 ConstantInitBuilder Builder(CGM); 3241 auto Elements = Builder.beginStruct(); 3242 3243 const std::string ClassName = "__ObjC_Protocol_Holder_Ugly_Hack"; 3244 const std::string CategoryName = "AnotherHack"; 3245 Elements.add(MakeConstantString(CategoryName)); 3246 Elements.add(MakeConstantString(ClassName)); 3247 // Instance method list 3248 Elements.addBitCast(GenerateMethodList( 3249 ClassName, CategoryName, {}, false), PtrTy); 3250 // Class method list 3251 Elements.addBitCast(GenerateMethodList( 3252 ClassName, CategoryName, {}, true), PtrTy); 3253 3254 // Protocol list 3255 ConstantInitBuilder ProtocolListBuilder(CGM); 3256 auto ProtocolList = ProtocolListBuilder.beginStruct(); 3257 ProtocolList.add(NULLPtr); 3258 ProtocolList.addInt(LongTy, ExistingProtocols.size()); 3259 auto ProtocolElements = ProtocolList.beginArray(PtrTy); 3260 for (auto iter = ExistingProtocols.begin(), endIter = ExistingProtocols.end(); 3261 iter != endIter ; iter++) { 3262 ProtocolElements.addBitCast(iter->getValue(), PtrTy); 3263 } 3264 ProtocolElements.finishAndAddTo(ProtocolList); 3265 Elements.addBitCast( 3266 ProtocolList.finishAndCreateGlobal(".objc_protocol_list", 3267 CGM.getPointerAlign()), 3268 PtrTy); 3269 Categories.push_back(llvm::ConstantExpr::getBitCast( 3270 Elements.finishAndCreateGlobal("", CGM.getPointerAlign()), 3271 PtrTy)); 3272 } 3273 3274 /// Libobjc2 uses a bitfield representation where small(ish) bitfields are 3275 /// stored in a 64-bit value with the low bit set to 1 and the remaining 63 3276 /// bits set to their values, LSB first, while larger ones are stored in a 3277 /// structure of this / form: 3278 /// 3279 /// struct { int32_t length; int32_t values[length]; }; 3280 /// 3281 /// The values in the array are stored in host-endian format, with the least 3282 /// significant bit being assumed to come first in the bitfield. Therefore, a 3283 /// bitfield with the 64th bit set will be (int64_t)&{ 2, [0, 1<<31] }, while a 3284 /// bitfield / with the 63rd bit set will be 1<<64. 3285 llvm::Constant *CGObjCGNU::MakeBitField(ArrayRef<bool> bits) { 3286 int bitCount = bits.size(); 3287 int ptrBits = CGM.getDataLayout().getPointerSizeInBits(); 3288 if (bitCount < ptrBits) { 3289 uint64_t val = 1; 3290 for (int i=0 ; i<bitCount ; ++i) { 3291 if (bits[i]) val |= 1ULL<<(i+1); 3292 } 3293 return llvm::ConstantInt::get(IntPtrTy, val); 3294 } 3295 SmallVector<llvm::Constant *, 8> values; 3296 int v=0; 3297 while (v < bitCount) { 3298 int32_t word = 0; 3299 for (int i=0 ; (i<32) && (v<bitCount) ; ++i) { 3300 if (bits[v]) word |= 1<<i; 3301 v++; 3302 } 3303 values.push_back(llvm::ConstantInt::get(Int32Ty, word)); 3304 } 3305 3306 ConstantInitBuilder builder(CGM); 3307 auto fields = builder.beginStruct(); 3308 fields.addInt(Int32Ty, values.size()); 3309 auto array = fields.beginArray(); 3310 for (auto v : values) array.add(v); 3311 array.finishAndAddTo(fields); 3312 3313 llvm::Constant *GS = 3314 fields.finishAndCreateGlobal("", CharUnits::fromQuantity(4)); 3315 llvm::Constant *ptr = llvm::ConstantExpr::getPtrToInt(GS, IntPtrTy); 3316 return ptr; 3317 } 3318 3319 llvm::Constant *CGObjCGNU::GenerateCategoryProtocolList(const 3320 ObjCCategoryDecl *OCD) { 3321 const auto &RefPro = OCD->getReferencedProtocols(); 3322 const auto RuntimeProtos = 3323 GetRuntimeProtocolList(RefPro.begin(), RefPro.end()); 3324 SmallVector<std::string, 16> Protocols; 3325 for (const auto *PD : RuntimeProtos) 3326 Protocols.push_back(PD->getNameAsString()); 3327 return GenerateProtocolList(Protocols); 3328 } 3329 3330 void CGObjCGNU::GenerateCategory(const ObjCCategoryImplDecl *OCD) { 3331 const ObjCInterfaceDecl *Class = OCD->getClassInterface(); 3332 std::string ClassName = Class->getNameAsString(); 3333 std::string CategoryName = OCD->getNameAsString(); 3334 3335 // Collect the names of referenced protocols 3336 const ObjCCategoryDecl *CatDecl = OCD->getCategoryDecl(); 3337 3338 ConstantInitBuilder Builder(CGM); 3339 auto Elements = Builder.beginStruct(); 3340 Elements.add(MakeConstantString(CategoryName)); 3341 Elements.add(MakeConstantString(ClassName)); 3342 // Instance method list 3343 SmallVector<ObjCMethodDecl*, 16> InstanceMethods; 3344 InstanceMethods.insert(InstanceMethods.begin(), OCD->instmeth_begin(), 3345 OCD->instmeth_end()); 3346 Elements.addBitCast( 3347 GenerateMethodList(ClassName, CategoryName, InstanceMethods, false), 3348 PtrTy); 3349 // Class method list 3350 3351 SmallVector<ObjCMethodDecl*, 16> ClassMethods; 3352 ClassMethods.insert(ClassMethods.begin(), OCD->classmeth_begin(), 3353 OCD->classmeth_end()); 3354 Elements.addBitCast( 3355 GenerateMethodList(ClassName, CategoryName, ClassMethods, true), 3356 PtrTy); 3357 // Protocol list 3358 Elements.addBitCast(GenerateCategoryProtocolList(CatDecl), PtrTy); 3359 if (isRuntime(ObjCRuntime::GNUstep, 2)) { 3360 const ObjCCategoryDecl *Category = 3361 Class->FindCategoryDeclaration(OCD->getIdentifier()); 3362 if (Category) { 3363 // Instance properties 3364 Elements.addBitCast(GeneratePropertyList(OCD, Category, false), PtrTy); 3365 // Class properties 3366 Elements.addBitCast(GeneratePropertyList(OCD, Category, true), PtrTy); 3367 } else { 3368 Elements.addNullPointer(PtrTy); 3369 Elements.addNullPointer(PtrTy); 3370 } 3371 } 3372 3373 Categories.push_back(llvm::ConstantExpr::getBitCast( 3374 Elements.finishAndCreateGlobal( 3375 std::string(".objc_category_")+ClassName+CategoryName, 3376 CGM.getPointerAlign()), 3377 PtrTy)); 3378 } 3379 3380 llvm::Constant *CGObjCGNU::GeneratePropertyList(const Decl *Container, 3381 const ObjCContainerDecl *OCD, 3382 bool isClassProperty, 3383 bool protocolOptionalProperties) { 3384 3385 SmallVector<const ObjCPropertyDecl *, 16> Properties; 3386 llvm::SmallPtrSet<const IdentifierInfo*, 16> PropertySet; 3387 bool isProtocol = isa<ObjCProtocolDecl>(OCD); 3388 ASTContext &Context = CGM.getContext(); 3389 3390 std::function<void(const ObjCProtocolDecl *Proto)> collectProtocolProperties 3391 = [&](const ObjCProtocolDecl *Proto) { 3392 for (const auto *P : Proto->protocols()) 3393 collectProtocolProperties(P); 3394 for (const auto *PD : Proto->properties()) { 3395 if (isClassProperty != PD->isClassProperty()) 3396 continue; 3397 // Skip any properties that are declared in protocols that this class 3398 // conforms to but are not actually implemented by this class. 3399 if (!isProtocol && !Context.getObjCPropertyImplDeclForPropertyDecl(PD, Container)) 3400 continue; 3401 if (!PropertySet.insert(PD->getIdentifier()).second) 3402 continue; 3403 Properties.push_back(PD); 3404 } 3405 }; 3406 3407 if (const ObjCInterfaceDecl *OID = dyn_cast<ObjCInterfaceDecl>(OCD)) 3408 for (const ObjCCategoryDecl *ClassExt : OID->known_extensions()) 3409 for (auto *PD : ClassExt->properties()) { 3410 if (isClassProperty != PD->isClassProperty()) 3411 continue; 3412 PropertySet.insert(PD->getIdentifier()); 3413 Properties.push_back(PD); 3414 } 3415 3416 for (const auto *PD : OCD->properties()) { 3417 if (isClassProperty != PD->isClassProperty()) 3418 continue; 3419 // If we're generating a list for a protocol, skip optional / required ones 3420 // when generating the other list. 3421 if (isProtocol && (protocolOptionalProperties != PD->isOptional())) 3422 continue; 3423 // Don't emit duplicate metadata for properties that were already in a 3424 // class extension. 3425 if (!PropertySet.insert(PD->getIdentifier()).second) 3426 continue; 3427 3428 Properties.push_back(PD); 3429 } 3430 3431 if (const ObjCInterfaceDecl *OID = dyn_cast<ObjCInterfaceDecl>(OCD)) 3432 for (const auto *P : OID->all_referenced_protocols()) 3433 collectProtocolProperties(P); 3434 else if (const ObjCCategoryDecl *CD = dyn_cast<ObjCCategoryDecl>(OCD)) 3435 for (const auto *P : CD->protocols()) 3436 collectProtocolProperties(P); 3437 3438 auto numProperties = Properties.size(); 3439 3440 if (numProperties == 0) 3441 return NULLPtr; 3442 3443 ConstantInitBuilder builder(CGM); 3444 auto propertyList = builder.beginStruct(); 3445 auto properties = PushPropertyListHeader(propertyList, numProperties); 3446 3447 // Add all of the property methods need adding to the method list and to the 3448 // property metadata list. 3449 for (auto *property : Properties) { 3450 bool isSynthesized = false; 3451 bool isDynamic = false; 3452 if (!isProtocol) { 3453 auto *propertyImpl = Context.getObjCPropertyImplDeclForPropertyDecl(property, Container); 3454 if (propertyImpl) { 3455 isSynthesized = (propertyImpl->getPropertyImplementation() == 3456 ObjCPropertyImplDecl::Synthesize); 3457 isDynamic = (propertyImpl->getPropertyImplementation() == 3458 ObjCPropertyImplDecl::Dynamic); 3459 } 3460 } 3461 PushProperty(properties, property, Container, isSynthesized, isDynamic); 3462 } 3463 properties.finishAndAddTo(propertyList); 3464 3465 return propertyList.finishAndCreateGlobal(".objc_property_list", 3466 CGM.getPointerAlign()); 3467 } 3468 3469 void CGObjCGNU::RegisterAlias(const ObjCCompatibleAliasDecl *OAD) { 3470 // Get the class declaration for which the alias is specified. 3471 ObjCInterfaceDecl *ClassDecl = 3472 const_cast<ObjCInterfaceDecl *>(OAD->getClassInterface()); 3473 ClassAliases.emplace_back(ClassDecl->getNameAsString(), 3474 OAD->getNameAsString()); 3475 } 3476 3477 void CGObjCGNU::GenerateClass(const ObjCImplementationDecl *OID) { 3478 ASTContext &Context = CGM.getContext(); 3479 3480 // Get the superclass name. 3481 const ObjCInterfaceDecl * SuperClassDecl = 3482 OID->getClassInterface()->getSuperClass(); 3483 std::string SuperClassName; 3484 if (SuperClassDecl) { 3485 SuperClassName = SuperClassDecl->getNameAsString(); 3486 EmitClassRef(SuperClassName); 3487 } 3488 3489 // Get the class name 3490 ObjCInterfaceDecl *ClassDecl = 3491 const_cast<ObjCInterfaceDecl *>(OID->getClassInterface()); 3492 std::string ClassName = ClassDecl->getNameAsString(); 3493 3494 // Emit the symbol that is used to generate linker errors if this class is 3495 // referenced in other modules but not declared. 3496 std::string classSymbolName = "__objc_class_name_" + ClassName; 3497 if (auto *symbol = TheModule.getGlobalVariable(classSymbolName)) { 3498 symbol->setInitializer(llvm::ConstantInt::get(LongTy, 0)); 3499 } else { 3500 new llvm::GlobalVariable(TheModule, LongTy, false, 3501 llvm::GlobalValue::ExternalLinkage, 3502 llvm::ConstantInt::get(LongTy, 0), 3503 classSymbolName); 3504 } 3505 3506 // Get the size of instances. 3507 int instanceSize = 3508 Context.getASTObjCImplementationLayout(OID).getSize().getQuantity(); 3509 3510 // Collect information about instance variables. 3511 SmallVector<llvm::Constant*, 16> IvarNames; 3512 SmallVector<llvm::Constant*, 16> IvarTypes; 3513 SmallVector<llvm::Constant*, 16> IvarOffsets; 3514 SmallVector<llvm::Constant*, 16> IvarAligns; 3515 SmallVector<Qualifiers::ObjCLifetime, 16> IvarOwnership; 3516 3517 ConstantInitBuilder IvarOffsetBuilder(CGM); 3518 auto IvarOffsetValues = IvarOffsetBuilder.beginArray(PtrToIntTy); 3519 SmallVector<bool, 16> WeakIvars; 3520 SmallVector<bool, 16> StrongIvars; 3521 3522 int superInstanceSize = !SuperClassDecl ? 0 : 3523 Context.getASTObjCInterfaceLayout(SuperClassDecl).getSize().getQuantity(); 3524 // For non-fragile ivars, set the instance size to 0 - {the size of just this 3525 // class}. The runtime will then set this to the correct value on load. 3526 if (CGM.getLangOpts().ObjCRuntime.isNonFragile()) { 3527 instanceSize = 0 - (instanceSize - superInstanceSize); 3528 } 3529 3530 for (const ObjCIvarDecl *IVD = ClassDecl->all_declared_ivar_begin(); IVD; 3531 IVD = IVD->getNextIvar()) { 3532 // Store the name 3533 IvarNames.push_back(MakeConstantString(IVD->getNameAsString())); 3534 // Get the type encoding for this ivar 3535 std::string TypeStr; 3536 Context.getObjCEncodingForType(IVD->getType(), TypeStr, IVD); 3537 IvarTypes.push_back(MakeConstantString(TypeStr)); 3538 IvarAligns.push_back(llvm::ConstantInt::get(IntTy, 3539 Context.getTypeSize(IVD->getType()))); 3540 // Get the offset 3541 uint64_t BaseOffset = ComputeIvarBaseOffset(CGM, OID, IVD); 3542 uint64_t Offset = BaseOffset; 3543 if (CGM.getLangOpts().ObjCRuntime.isNonFragile()) { 3544 Offset = BaseOffset - superInstanceSize; 3545 } 3546 llvm::Constant *OffsetValue = llvm::ConstantInt::get(IntTy, Offset); 3547 // Create the direct offset value 3548 std::string OffsetName = "__objc_ivar_offset_value_" + ClassName +"." + 3549 IVD->getNameAsString(); 3550 3551 llvm::GlobalVariable *OffsetVar = TheModule.getGlobalVariable(OffsetName); 3552 if (OffsetVar) { 3553 OffsetVar->setInitializer(OffsetValue); 3554 // If this is the real definition, change its linkage type so that 3555 // different modules will use this one, rather than their private 3556 // copy. 3557 OffsetVar->setLinkage(llvm::GlobalValue::ExternalLinkage); 3558 } else 3559 OffsetVar = new llvm::GlobalVariable(TheModule, Int32Ty, 3560 false, llvm::GlobalValue::ExternalLinkage, 3561 OffsetValue, OffsetName); 3562 IvarOffsets.push_back(OffsetValue); 3563 IvarOffsetValues.add(OffsetVar); 3564 Qualifiers::ObjCLifetime lt = IVD->getType().getQualifiers().getObjCLifetime(); 3565 IvarOwnership.push_back(lt); 3566 switch (lt) { 3567 case Qualifiers::OCL_Strong: 3568 StrongIvars.push_back(true); 3569 WeakIvars.push_back(false); 3570 break; 3571 case Qualifiers::OCL_Weak: 3572 StrongIvars.push_back(false); 3573 WeakIvars.push_back(true); 3574 break; 3575 default: 3576 StrongIvars.push_back(false); 3577 WeakIvars.push_back(false); 3578 } 3579 } 3580 llvm::Constant *StrongIvarBitmap = MakeBitField(StrongIvars); 3581 llvm::Constant *WeakIvarBitmap = MakeBitField(WeakIvars); 3582 llvm::GlobalVariable *IvarOffsetArray = 3583 IvarOffsetValues.finishAndCreateGlobal(".ivar.offsets", 3584 CGM.getPointerAlign()); 3585 3586 // Collect information about instance methods 3587 SmallVector<const ObjCMethodDecl*, 16> InstanceMethods; 3588 InstanceMethods.insert(InstanceMethods.begin(), OID->instmeth_begin(), 3589 OID->instmeth_end()); 3590 3591 SmallVector<const ObjCMethodDecl*, 16> ClassMethods; 3592 ClassMethods.insert(ClassMethods.begin(), OID->classmeth_begin(), 3593 OID->classmeth_end()); 3594 3595 llvm::Constant *Properties = GeneratePropertyList(OID, ClassDecl); 3596 3597 // Collect the names of referenced protocols 3598 auto RefProtocols = ClassDecl->protocols(); 3599 auto RuntimeProtocols = 3600 GetRuntimeProtocolList(RefProtocols.begin(), RefProtocols.end()); 3601 SmallVector<std::string, 16> Protocols; 3602 for (const auto *I : RuntimeProtocols) 3603 Protocols.push_back(I->getNameAsString()); 3604 3605 // Get the superclass pointer. 3606 llvm::Constant *SuperClass; 3607 if (!SuperClassName.empty()) { 3608 SuperClass = MakeConstantString(SuperClassName, ".super_class_name"); 3609 } else { 3610 SuperClass = llvm::ConstantPointerNull::get(PtrToInt8Ty); 3611 } 3612 // Empty vector used to construct empty method lists 3613 SmallVector<llvm::Constant*, 1> empty; 3614 // Generate the method and instance variable lists 3615 llvm::Constant *MethodList = GenerateMethodList(ClassName, "", 3616 InstanceMethods, false); 3617 llvm::Constant *ClassMethodList = GenerateMethodList(ClassName, "", 3618 ClassMethods, true); 3619 llvm::Constant *IvarList = GenerateIvarList(IvarNames, IvarTypes, 3620 IvarOffsets, IvarAligns, IvarOwnership); 3621 // Irrespective of whether we are compiling for a fragile or non-fragile ABI, 3622 // we emit a symbol containing the offset for each ivar in the class. This 3623 // allows code compiled for the non-Fragile ABI to inherit from code compiled 3624 // for the legacy ABI, without causing problems. The converse is also 3625 // possible, but causes all ivar accesses to be fragile. 3626 3627 // Offset pointer for getting at the correct field in the ivar list when 3628 // setting up the alias. These are: The base address for the global, the 3629 // ivar array (second field), the ivar in this list (set for each ivar), and 3630 // the offset (third field in ivar structure) 3631 llvm::Type *IndexTy = Int32Ty; 3632 llvm::Constant *offsetPointerIndexes[] = {Zeros[0], 3633 llvm::ConstantInt::get(IndexTy, ClassABIVersion > 1 ? 2 : 1), nullptr, 3634 llvm::ConstantInt::get(IndexTy, ClassABIVersion > 1 ? 3 : 2) }; 3635 3636 unsigned ivarIndex = 0; 3637 for (const ObjCIvarDecl *IVD = ClassDecl->all_declared_ivar_begin(); IVD; 3638 IVD = IVD->getNextIvar()) { 3639 const std::string Name = GetIVarOffsetVariableName(ClassDecl, IVD); 3640 offsetPointerIndexes[2] = llvm::ConstantInt::get(IndexTy, ivarIndex); 3641 // Get the correct ivar field 3642 llvm::Constant *offsetValue = llvm::ConstantExpr::getGetElementPtr( 3643 cast<llvm::GlobalVariable>(IvarList)->getValueType(), IvarList, 3644 offsetPointerIndexes); 3645 // Get the existing variable, if one exists. 3646 llvm::GlobalVariable *offset = TheModule.getNamedGlobal(Name); 3647 if (offset) { 3648 offset->setInitializer(offsetValue); 3649 // If this is the real definition, change its linkage type so that 3650 // different modules will use this one, rather than their private 3651 // copy. 3652 offset->setLinkage(llvm::GlobalValue::ExternalLinkage); 3653 } else 3654 // Add a new alias if there isn't one already. 3655 new llvm::GlobalVariable(TheModule, offsetValue->getType(), 3656 false, llvm::GlobalValue::ExternalLinkage, offsetValue, Name); 3657 ++ivarIndex; 3658 } 3659 llvm::Constant *ZeroPtr = llvm::ConstantInt::get(IntPtrTy, 0); 3660 3661 //Generate metaclass for class methods 3662 llvm::Constant *MetaClassStruct = GenerateClassStructure( 3663 NULLPtr, NULLPtr, 0x12L, ClassName.c_str(), nullptr, Zeros[0], 3664 NULLPtr, ClassMethodList, NULLPtr, NULLPtr, 3665 GeneratePropertyList(OID, ClassDecl, true), ZeroPtr, ZeroPtr, true); 3666 CGM.setGVProperties(cast<llvm::GlobalValue>(MetaClassStruct), 3667 OID->getClassInterface()); 3668 3669 // Generate the class structure 3670 llvm::Constant *ClassStruct = GenerateClassStructure( 3671 MetaClassStruct, SuperClass, 0x11L, ClassName.c_str(), nullptr, 3672 llvm::ConstantInt::get(LongTy, instanceSize), IvarList, MethodList, 3673 GenerateProtocolList(Protocols), IvarOffsetArray, Properties, 3674 StrongIvarBitmap, WeakIvarBitmap); 3675 CGM.setGVProperties(cast<llvm::GlobalValue>(ClassStruct), 3676 OID->getClassInterface()); 3677 3678 // Resolve the class aliases, if they exist. 3679 if (ClassPtrAlias) { 3680 ClassPtrAlias->replaceAllUsesWith( 3681 llvm::ConstantExpr::getBitCast(ClassStruct, IdTy)); 3682 ClassPtrAlias->eraseFromParent(); 3683 ClassPtrAlias = nullptr; 3684 } 3685 if (MetaClassPtrAlias) { 3686 MetaClassPtrAlias->replaceAllUsesWith( 3687 llvm::ConstantExpr::getBitCast(MetaClassStruct, IdTy)); 3688 MetaClassPtrAlias->eraseFromParent(); 3689 MetaClassPtrAlias = nullptr; 3690 } 3691 3692 // Add class structure to list to be added to the symtab later 3693 ClassStruct = llvm::ConstantExpr::getBitCast(ClassStruct, PtrToInt8Ty); 3694 Classes.push_back(ClassStruct); 3695 } 3696 3697 llvm::Function *CGObjCGNU::ModuleInitFunction() { 3698 // Only emit an ObjC load function if no Objective-C stuff has been called 3699 if (Classes.empty() && Categories.empty() && ConstantStrings.empty() && 3700 ExistingProtocols.empty() && SelectorTable.empty()) 3701 return nullptr; 3702 3703 // Add all referenced protocols to a category. 3704 GenerateProtocolHolderCategory(); 3705 3706 llvm::StructType *selStructTy = 3707 dyn_cast<llvm::StructType>(SelectorTy->getElementType()); 3708 llvm::Type *selStructPtrTy = SelectorTy; 3709 if (!selStructTy) { 3710 selStructTy = llvm::StructType::get(CGM.getLLVMContext(), 3711 { PtrToInt8Ty, PtrToInt8Ty }); 3712 selStructPtrTy = llvm::PointerType::getUnqual(selStructTy); 3713 } 3714 3715 // Generate statics list: 3716 llvm::Constant *statics = NULLPtr; 3717 if (!ConstantStrings.empty()) { 3718 llvm::GlobalVariable *fileStatics = [&] { 3719 ConstantInitBuilder builder(CGM); 3720 auto staticsStruct = builder.beginStruct(); 3721 3722 StringRef stringClass = CGM.getLangOpts().ObjCConstantStringClass; 3723 if (stringClass.empty()) stringClass = "NXConstantString"; 3724 staticsStruct.add(MakeConstantString(stringClass, 3725 ".objc_static_class_name")); 3726 3727 auto array = staticsStruct.beginArray(); 3728 array.addAll(ConstantStrings); 3729 array.add(NULLPtr); 3730 array.finishAndAddTo(staticsStruct); 3731 3732 return staticsStruct.finishAndCreateGlobal(".objc_statics", 3733 CGM.getPointerAlign()); 3734 }(); 3735 3736 ConstantInitBuilder builder(CGM); 3737 auto allStaticsArray = builder.beginArray(fileStatics->getType()); 3738 allStaticsArray.add(fileStatics); 3739 allStaticsArray.addNullPointer(fileStatics->getType()); 3740 3741 statics = allStaticsArray.finishAndCreateGlobal(".objc_statics_ptr", 3742 CGM.getPointerAlign()); 3743 statics = llvm::ConstantExpr::getBitCast(statics, PtrTy); 3744 } 3745 3746 // Array of classes, categories, and constant objects. 3747 3748 SmallVector<llvm::GlobalAlias*, 16> selectorAliases; 3749 unsigned selectorCount; 3750 3751 // Pointer to an array of selectors used in this module. 3752 llvm::GlobalVariable *selectorList = [&] { 3753 ConstantInitBuilder builder(CGM); 3754 auto selectors = builder.beginArray(selStructTy); 3755 auto &table = SelectorTable; // MSVC workaround 3756 std::vector<Selector> allSelectors; 3757 for (auto &entry : table) 3758 allSelectors.push_back(entry.first); 3759 llvm::sort(allSelectors); 3760 3761 for (auto &untypedSel : allSelectors) { 3762 std::string selNameStr = untypedSel.getAsString(); 3763 llvm::Constant *selName = ExportUniqueString(selNameStr, ".objc_sel_name"); 3764 3765 for (TypedSelector &sel : table[untypedSel]) { 3766 llvm::Constant *selectorTypeEncoding = NULLPtr; 3767 if (!sel.first.empty()) 3768 selectorTypeEncoding = 3769 MakeConstantString(sel.first, ".objc_sel_types"); 3770 3771 auto selStruct = selectors.beginStruct(selStructTy); 3772 selStruct.add(selName); 3773 selStruct.add(selectorTypeEncoding); 3774 selStruct.finishAndAddTo(selectors); 3775 3776 // Store the selector alias for later replacement 3777 selectorAliases.push_back(sel.second); 3778 } 3779 } 3780 3781 // Remember the number of entries in the selector table. 3782 selectorCount = selectors.size(); 3783 3784 // NULL-terminate the selector list. This should not actually be required, 3785 // because the selector list has a length field. Unfortunately, the GCC 3786 // runtime decides to ignore the length field and expects a NULL terminator, 3787 // and GCC cooperates with this by always setting the length to 0. 3788 auto selStruct = selectors.beginStruct(selStructTy); 3789 selStruct.add(NULLPtr); 3790 selStruct.add(NULLPtr); 3791 selStruct.finishAndAddTo(selectors); 3792 3793 return selectors.finishAndCreateGlobal(".objc_selector_list", 3794 CGM.getPointerAlign()); 3795 }(); 3796 3797 // Now that all of the static selectors exist, create pointers to them. 3798 for (unsigned i = 0; i < selectorCount; ++i) { 3799 llvm::Constant *idxs[] = { 3800 Zeros[0], 3801 llvm::ConstantInt::get(Int32Ty, i) 3802 }; 3803 // FIXME: We're generating redundant loads and stores here! 3804 llvm::Constant *selPtr = llvm::ConstantExpr::getGetElementPtr( 3805 selectorList->getValueType(), selectorList, idxs); 3806 // If selectors are defined as an opaque type, cast the pointer to this 3807 // type. 3808 selPtr = llvm::ConstantExpr::getBitCast(selPtr, SelectorTy); 3809 selectorAliases[i]->replaceAllUsesWith(selPtr); 3810 selectorAliases[i]->eraseFromParent(); 3811 } 3812 3813 llvm::GlobalVariable *symtab = [&] { 3814 ConstantInitBuilder builder(CGM); 3815 auto symtab = builder.beginStruct(); 3816 3817 // Number of static selectors 3818 symtab.addInt(LongTy, selectorCount); 3819 3820 symtab.addBitCast(selectorList, selStructPtrTy); 3821 3822 // Number of classes defined. 3823 symtab.addInt(CGM.Int16Ty, Classes.size()); 3824 // Number of categories defined 3825 symtab.addInt(CGM.Int16Ty, Categories.size()); 3826 3827 // Create an array of classes, then categories, then static object instances 3828 auto classList = symtab.beginArray(PtrToInt8Ty); 3829 classList.addAll(Classes); 3830 classList.addAll(Categories); 3831 // NULL-terminated list of static object instances (mainly constant strings) 3832 classList.add(statics); 3833 classList.add(NULLPtr); 3834 classList.finishAndAddTo(symtab); 3835 3836 // Construct the symbol table. 3837 return symtab.finishAndCreateGlobal("", CGM.getPointerAlign()); 3838 }(); 3839 3840 // The symbol table is contained in a module which has some version-checking 3841 // constants 3842 llvm::Constant *module = [&] { 3843 llvm::Type *moduleEltTys[] = { 3844 LongTy, LongTy, PtrToInt8Ty, symtab->getType(), IntTy 3845 }; 3846 llvm::StructType *moduleTy = 3847 llvm::StructType::get(CGM.getLLVMContext(), 3848 makeArrayRef(moduleEltTys).drop_back(unsigned(RuntimeVersion < 10))); 3849 3850 ConstantInitBuilder builder(CGM); 3851 auto module = builder.beginStruct(moduleTy); 3852 // Runtime version, used for ABI compatibility checking. 3853 module.addInt(LongTy, RuntimeVersion); 3854 // sizeof(ModuleTy) 3855 module.addInt(LongTy, CGM.getDataLayout().getTypeStoreSize(moduleTy)); 3856 3857 // The path to the source file where this module was declared 3858 SourceManager &SM = CGM.getContext().getSourceManager(); 3859 const FileEntry *mainFile = SM.getFileEntryForID(SM.getMainFileID()); 3860 std::string path = 3861 (Twine(mainFile->getDir()->getName()) + "/" + mainFile->getName()).str(); 3862 module.add(MakeConstantString(path, ".objc_source_file_name")); 3863 module.add(symtab); 3864 3865 if (RuntimeVersion >= 10) { 3866 switch (CGM.getLangOpts().getGC()) { 3867 case LangOptions::GCOnly: 3868 module.addInt(IntTy, 2); 3869 break; 3870 case LangOptions::NonGC: 3871 if (CGM.getLangOpts().ObjCAutoRefCount) 3872 module.addInt(IntTy, 1); 3873 else 3874 module.addInt(IntTy, 0); 3875 break; 3876 case LangOptions::HybridGC: 3877 module.addInt(IntTy, 1); 3878 break; 3879 } 3880 } 3881 3882 return module.finishAndCreateGlobal("", CGM.getPointerAlign()); 3883 }(); 3884 3885 // Create the load function calling the runtime entry point with the module 3886 // structure 3887 llvm::Function * LoadFunction = llvm::Function::Create( 3888 llvm::FunctionType::get(llvm::Type::getVoidTy(VMContext), false), 3889 llvm::GlobalValue::InternalLinkage, ".objc_load_function", 3890 &TheModule); 3891 llvm::BasicBlock *EntryBB = 3892 llvm::BasicBlock::Create(VMContext, "entry", LoadFunction); 3893 CGBuilderTy Builder(CGM, VMContext); 3894 Builder.SetInsertPoint(EntryBB); 3895 3896 llvm::FunctionType *FT = 3897 llvm::FunctionType::get(Builder.getVoidTy(), module->getType(), true); 3898 llvm::FunctionCallee Register = 3899 CGM.CreateRuntimeFunction(FT, "__objc_exec_class"); 3900 Builder.CreateCall(Register, module); 3901 3902 if (!ClassAliases.empty()) { 3903 llvm::Type *ArgTypes[2] = {PtrTy, PtrToInt8Ty}; 3904 llvm::FunctionType *RegisterAliasTy = 3905 llvm::FunctionType::get(Builder.getVoidTy(), 3906 ArgTypes, false); 3907 llvm::Function *RegisterAlias = llvm::Function::Create( 3908 RegisterAliasTy, 3909 llvm::GlobalValue::ExternalWeakLinkage, "class_registerAlias_np", 3910 &TheModule); 3911 llvm::BasicBlock *AliasBB = 3912 llvm::BasicBlock::Create(VMContext, "alias", LoadFunction); 3913 llvm::BasicBlock *NoAliasBB = 3914 llvm::BasicBlock::Create(VMContext, "no_alias", LoadFunction); 3915 3916 // Branch based on whether the runtime provided class_registerAlias_np() 3917 llvm::Value *HasRegisterAlias = Builder.CreateICmpNE(RegisterAlias, 3918 llvm::Constant::getNullValue(RegisterAlias->getType())); 3919 Builder.CreateCondBr(HasRegisterAlias, AliasBB, NoAliasBB); 3920 3921 // The true branch (has alias registration function): 3922 Builder.SetInsertPoint(AliasBB); 3923 // Emit alias registration calls: 3924 for (std::vector<ClassAliasPair>::iterator iter = ClassAliases.begin(); 3925 iter != ClassAliases.end(); ++iter) { 3926 llvm::Constant *TheClass = 3927 TheModule.getGlobalVariable("_OBJC_CLASS_" + iter->first, true); 3928 if (TheClass) { 3929 TheClass = llvm::ConstantExpr::getBitCast(TheClass, PtrTy); 3930 Builder.CreateCall(RegisterAlias, 3931 {TheClass, MakeConstantString(iter->second)}); 3932 } 3933 } 3934 // Jump to end: 3935 Builder.CreateBr(NoAliasBB); 3936 3937 // Missing alias registration function, just return from the function: 3938 Builder.SetInsertPoint(NoAliasBB); 3939 } 3940 Builder.CreateRetVoid(); 3941 3942 return LoadFunction; 3943 } 3944 3945 llvm::Function *CGObjCGNU::GenerateMethod(const ObjCMethodDecl *OMD, 3946 const ObjCContainerDecl *CD) { 3947 CodeGenTypes &Types = CGM.getTypes(); 3948 llvm::FunctionType *MethodTy = 3949 Types.GetFunctionType(Types.arrangeObjCMethodDeclaration(OMD)); 3950 std::string FunctionName = getSymbolNameForMethod(OMD); 3951 3952 llvm::Function *Method 3953 = llvm::Function::Create(MethodTy, 3954 llvm::GlobalValue::InternalLinkage, 3955 FunctionName, 3956 &TheModule); 3957 return Method; 3958 } 3959 3960 void CGObjCGNU::GenerateDirectMethodPrologue(CodeGenFunction &CGF, 3961 llvm::Function *Fn, 3962 const ObjCMethodDecl *OMD, 3963 const ObjCContainerDecl *CD) { 3964 // GNU runtime doesn't support direct calls at this time 3965 } 3966 3967 llvm::FunctionCallee CGObjCGNU::GetPropertyGetFunction() { 3968 return GetPropertyFn; 3969 } 3970 3971 llvm::FunctionCallee CGObjCGNU::GetPropertySetFunction() { 3972 return SetPropertyFn; 3973 } 3974 3975 llvm::FunctionCallee CGObjCGNU::GetOptimizedPropertySetFunction(bool atomic, 3976 bool copy) { 3977 return nullptr; 3978 } 3979 3980 llvm::FunctionCallee CGObjCGNU::GetGetStructFunction() { 3981 return GetStructPropertyFn; 3982 } 3983 3984 llvm::FunctionCallee CGObjCGNU::GetSetStructFunction() { 3985 return SetStructPropertyFn; 3986 } 3987 3988 llvm::FunctionCallee CGObjCGNU::GetCppAtomicObjectGetFunction() { 3989 return nullptr; 3990 } 3991 3992 llvm::FunctionCallee CGObjCGNU::GetCppAtomicObjectSetFunction() { 3993 return nullptr; 3994 } 3995 3996 llvm::FunctionCallee CGObjCGNU::EnumerationMutationFunction() { 3997 return EnumerationMutationFn; 3998 } 3999 4000 void CGObjCGNU::EmitSynchronizedStmt(CodeGenFunction &CGF, 4001 const ObjCAtSynchronizedStmt &S) { 4002 EmitAtSynchronizedStmt(CGF, S, SyncEnterFn, SyncExitFn); 4003 } 4004 4005 4006 void CGObjCGNU::EmitTryStmt(CodeGenFunction &CGF, 4007 const ObjCAtTryStmt &S) { 4008 // Unlike the Apple non-fragile runtimes, which also uses 4009 // unwind-based zero cost exceptions, the GNU Objective C runtime's 4010 // EH support isn't a veneer over C++ EH. Instead, exception 4011 // objects are created by objc_exception_throw and destroyed by 4012 // the personality function; this avoids the need for bracketing 4013 // catch handlers with calls to __blah_begin_catch/__blah_end_catch 4014 // (or even _Unwind_DeleteException), but probably doesn't 4015 // interoperate very well with foreign exceptions. 4016 // 4017 // In Objective-C++ mode, we actually emit something equivalent to the C++ 4018 // exception handler. 4019 EmitTryCatchStmt(CGF, S, EnterCatchFn, ExitCatchFn, ExceptionReThrowFn); 4020 } 4021 4022 void CGObjCGNU::EmitThrowStmt(CodeGenFunction &CGF, 4023 const ObjCAtThrowStmt &S, 4024 bool ClearInsertionPoint) { 4025 llvm::Value *ExceptionAsObject; 4026 bool isRethrow = false; 4027 4028 if (const Expr *ThrowExpr = S.getThrowExpr()) { 4029 llvm::Value *Exception = CGF.EmitObjCThrowOperand(ThrowExpr); 4030 ExceptionAsObject = Exception; 4031 } else { 4032 assert((!CGF.ObjCEHValueStack.empty() && CGF.ObjCEHValueStack.back()) && 4033 "Unexpected rethrow outside @catch block."); 4034 ExceptionAsObject = CGF.ObjCEHValueStack.back(); 4035 isRethrow = true; 4036 } 4037 if (isRethrow && usesSEHExceptions) { 4038 // For SEH, ExceptionAsObject may be undef, because the catch handler is 4039 // not passed it for catchalls and so it is not visible to the catch 4040 // funclet. The real thrown object will still be live on the stack at this 4041 // point and will be rethrown. If we are explicitly rethrowing the object 4042 // that was passed into the `@catch` block, then this code path is not 4043 // reached and we will instead call `objc_exception_throw` with an explicit 4044 // argument. 4045 llvm::CallBase *Throw = CGF.EmitRuntimeCallOrInvoke(ExceptionReThrowFn); 4046 Throw->setDoesNotReturn(); 4047 } 4048 else { 4049 ExceptionAsObject = CGF.Builder.CreateBitCast(ExceptionAsObject, IdTy); 4050 llvm::CallBase *Throw = 4051 CGF.EmitRuntimeCallOrInvoke(ExceptionThrowFn, ExceptionAsObject); 4052 Throw->setDoesNotReturn(); 4053 } 4054 CGF.Builder.CreateUnreachable(); 4055 if (ClearInsertionPoint) 4056 CGF.Builder.ClearInsertionPoint(); 4057 } 4058 4059 llvm::Value * CGObjCGNU::EmitObjCWeakRead(CodeGenFunction &CGF, 4060 Address AddrWeakObj) { 4061 CGBuilderTy &B = CGF.Builder; 4062 AddrWeakObj = EnforceType(B, AddrWeakObj, PtrToIdTy); 4063 return B.CreateCall(WeakReadFn, AddrWeakObj.getPointer()); 4064 } 4065 4066 void CGObjCGNU::EmitObjCWeakAssign(CodeGenFunction &CGF, 4067 llvm::Value *src, Address dst) { 4068 CGBuilderTy &B = CGF.Builder; 4069 src = EnforceType(B, src, IdTy); 4070 dst = EnforceType(B, dst, PtrToIdTy); 4071 B.CreateCall(WeakAssignFn, {src, dst.getPointer()}); 4072 } 4073 4074 void CGObjCGNU::EmitObjCGlobalAssign(CodeGenFunction &CGF, 4075 llvm::Value *src, Address dst, 4076 bool threadlocal) { 4077 CGBuilderTy &B = CGF.Builder; 4078 src = EnforceType(B, src, IdTy); 4079 dst = EnforceType(B, dst, PtrToIdTy); 4080 // FIXME. Add threadloca assign API 4081 assert(!threadlocal && "EmitObjCGlobalAssign - Threal Local API NYI"); 4082 B.CreateCall(GlobalAssignFn, {src, dst.getPointer()}); 4083 } 4084 4085 void CGObjCGNU::EmitObjCIvarAssign(CodeGenFunction &CGF, 4086 llvm::Value *src, Address dst, 4087 llvm::Value *ivarOffset) { 4088 CGBuilderTy &B = CGF.Builder; 4089 src = EnforceType(B, src, IdTy); 4090 dst = EnforceType(B, dst, IdTy); 4091 B.CreateCall(IvarAssignFn, {src, dst.getPointer(), ivarOffset}); 4092 } 4093 4094 void CGObjCGNU::EmitObjCStrongCastAssign(CodeGenFunction &CGF, 4095 llvm::Value *src, Address dst) { 4096 CGBuilderTy &B = CGF.Builder; 4097 src = EnforceType(B, src, IdTy); 4098 dst = EnforceType(B, dst, PtrToIdTy); 4099 B.CreateCall(StrongCastAssignFn, {src, dst.getPointer()}); 4100 } 4101 4102 void CGObjCGNU::EmitGCMemmoveCollectable(CodeGenFunction &CGF, 4103 Address DestPtr, 4104 Address SrcPtr, 4105 llvm::Value *Size) { 4106 CGBuilderTy &B = CGF.Builder; 4107 DestPtr = EnforceType(B, DestPtr, PtrTy); 4108 SrcPtr = EnforceType(B, SrcPtr, PtrTy); 4109 4110 B.CreateCall(MemMoveFn, {DestPtr.getPointer(), SrcPtr.getPointer(), Size}); 4111 } 4112 4113 llvm::GlobalVariable *CGObjCGNU::ObjCIvarOffsetVariable( 4114 const ObjCInterfaceDecl *ID, 4115 const ObjCIvarDecl *Ivar) { 4116 const std::string Name = GetIVarOffsetVariableName(ID, Ivar); 4117 // Emit the variable and initialize it with what we think the correct value 4118 // is. This allows code compiled with non-fragile ivars to work correctly 4119 // when linked against code which isn't (most of the time). 4120 llvm::GlobalVariable *IvarOffsetPointer = TheModule.getNamedGlobal(Name); 4121 if (!IvarOffsetPointer) 4122 IvarOffsetPointer = new llvm::GlobalVariable(TheModule, 4123 llvm::Type::getInt32PtrTy(VMContext), false, 4124 llvm::GlobalValue::ExternalLinkage, nullptr, Name); 4125 return IvarOffsetPointer; 4126 } 4127 4128 LValue CGObjCGNU::EmitObjCValueForIvar(CodeGenFunction &CGF, 4129 QualType ObjectTy, 4130 llvm::Value *BaseValue, 4131 const ObjCIvarDecl *Ivar, 4132 unsigned CVRQualifiers) { 4133 const ObjCInterfaceDecl *ID = 4134 ObjectTy->castAs<ObjCObjectType>()->getInterface(); 4135 return EmitValueForIvarAtOffset(CGF, ID, BaseValue, Ivar, CVRQualifiers, 4136 EmitIvarOffset(CGF, ID, Ivar)); 4137 } 4138 4139 static const ObjCInterfaceDecl *FindIvarInterface(ASTContext &Context, 4140 const ObjCInterfaceDecl *OID, 4141 const ObjCIvarDecl *OIVD) { 4142 for (const ObjCIvarDecl *next = OID->all_declared_ivar_begin(); next; 4143 next = next->getNextIvar()) { 4144 if (OIVD == next) 4145 return OID; 4146 } 4147 4148 // Otherwise check in the super class. 4149 if (const ObjCInterfaceDecl *Super = OID->getSuperClass()) 4150 return FindIvarInterface(Context, Super, OIVD); 4151 4152 return nullptr; 4153 } 4154 4155 llvm::Value *CGObjCGNU::EmitIvarOffset(CodeGenFunction &CGF, 4156 const ObjCInterfaceDecl *Interface, 4157 const ObjCIvarDecl *Ivar) { 4158 if (CGM.getLangOpts().ObjCRuntime.isNonFragile()) { 4159 Interface = FindIvarInterface(CGM.getContext(), Interface, Ivar); 4160 4161 // The MSVC linker cannot have a single global defined as LinkOnceAnyLinkage 4162 // and ExternalLinkage, so create a reference to the ivar global and rely on 4163 // the definition being created as part of GenerateClass. 4164 if (RuntimeVersion < 10 || 4165 CGF.CGM.getTarget().getTriple().isKnownWindowsMSVCEnvironment()) 4166 return CGF.Builder.CreateZExtOrBitCast( 4167 CGF.Builder.CreateAlignedLoad( 4168 Int32Ty, CGF.Builder.CreateAlignedLoad( 4169 llvm::Type::getInt32PtrTy(VMContext), 4170 ObjCIvarOffsetVariable(Interface, Ivar), 4171 CGF.getPointerAlign(), "ivar"), 4172 CharUnits::fromQuantity(4)), 4173 PtrDiffTy); 4174 std::string name = "__objc_ivar_offset_value_" + 4175 Interface->getNameAsString() +"." + Ivar->getNameAsString(); 4176 CharUnits Align = CGM.getIntAlign(); 4177 llvm::Value *Offset = TheModule.getGlobalVariable(name); 4178 if (!Offset) { 4179 auto GV = new llvm::GlobalVariable(TheModule, IntTy, 4180 false, llvm::GlobalValue::LinkOnceAnyLinkage, 4181 llvm::Constant::getNullValue(IntTy), name); 4182 GV->setAlignment(Align.getAsAlign()); 4183 Offset = GV; 4184 } 4185 Offset = CGF.Builder.CreateAlignedLoad(IntTy, Offset, Align); 4186 if (Offset->getType() != PtrDiffTy) 4187 Offset = CGF.Builder.CreateZExtOrBitCast(Offset, PtrDiffTy); 4188 return Offset; 4189 } 4190 uint64_t Offset = ComputeIvarBaseOffset(CGF.CGM, Interface, Ivar); 4191 return llvm::ConstantInt::get(PtrDiffTy, Offset, /*isSigned*/true); 4192 } 4193 4194 CGObjCRuntime * 4195 clang::CodeGen::CreateGNUObjCRuntime(CodeGenModule &CGM) { 4196 auto Runtime = CGM.getLangOpts().ObjCRuntime; 4197 switch (Runtime.getKind()) { 4198 case ObjCRuntime::GNUstep: 4199 if (Runtime.getVersion() >= VersionTuple(2, 0)) 4200 return new CGObjCGNUstep2(CGM); 4201 return new CGObjCGNUstep(CGM); 4202 4203 case ObjCRuntime::GCC: 4204 return new CGObjCGCC(CGM); 4205 4206 case ObjCRuntime::ObjFW: 4207 return new CGObjCObjFW(CGM); 4208 4209 case ObjCRuntime::FragileMacOSX: 4210 case ObjCRuntime::MacOSX: 4211 case ObjCRuntime::iOS: 4212 case ObjCRuntime::WatchOS: 4213 llvm_unreachable("these runtimes are not GNU runtimes"); 4214 } 4215 llvm_unreachable("bad runtime"); 4216 } 4217