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