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