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