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