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//===------- CGObjCGNU.cpp - Emit LLVM Code from ASTs for a Module --------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This provides Objective-C code generation targeting the GNU runtime. The
// class in this file generates structures used by the GNU Objective-C runtime
// library. These structures are defined in objc/objc.h and objc/objc-api.h in
// the GNU runtime distribution.
//
//===----------------------------------------------------------------------===//
#include "CGCXXABI.h"
#include "CGCleanup.h"
#include "CGObjCRuntime.h"
#include "CodeGenFunction.h"
#include "CodeGenModule.h"
#include "clang/AST/ASTContext.h"
#include "clang/AST/Attr.h"
#include "clang/AST/Decl.h"
#include "clang/AST/DeclObjC.h"
#include "clang/AST/RecordLayout.h"
#include "clang/AST/StmtObjC.h"
#include "clang/Basic/FileManager.h"
#include "clang/Basic/SourceManager.h"
#include "clang/CodeGen/ConstantInitBuilder.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/StringMap.h"
#include "llvm/IR/DataLayout.h"
#include "llvm/IR/Intrinsics.h"
#include "llvm/IR/LLVMContext.h"
#include "llvm/IR/Module.h"
#include "llvm/Support/Compiler.h"
#include "llvm/Support/ConvertUTF.h"
#include <cctype>
using namespace clang;
using namespace CodeGen;
namespace {
/// Class that lazily initialises the runtime function. Avoids inserting the
/// types and the function declaration into a module if they're not used, and
/// avoids constructing the type more than once if it's used more than once.
class LazyRuntimeFunction {
CodeGenModule *CGM;
llvm::FunctionType *FTy;
const char *FunctionName;
llvm::FunctionCallee Function;
public:
/// Constructor leaves this class uninitialized, because it is intended to
/// be used as a field in another class and not all of the types that are
/// used as arguments will necessarily be available at construction time.
LazyRuntimeFunction()
: CGM(nullptr), FunctionName(nullptr), Function(nullptr) {}
/// Initialises the lazy function with the name, return type, and the types
/// of the arguments.
template <typename... Tys>
void init(CodeGenModule *Mod, const char *name, llvm::Type *RetTy,
Tys *... Types) {
CGM = Mod;
FunctionName = name;
Function = nullptr;
if(sizeof...(Tys)) {
SmallVector<llvm::Type *, 8> ArgTys({Types...});
FTy = llvm::FunctionType::get(RetTy, ArgTys, false);
}
else {
FTy = llvm::FunctionType::get(RetTy, None, false);
}
}
llvm::FunctionType *getType() { return FTy; }
/// Overloaded cast operator, allows the class to be implicitly cast to an
/// LLVM constant.
operator llvm::FunctionCallee() {
if (!Function) {
if (!FunctionName)
return nullptr;
Function = CGM->CreateRuntimeFunction(FTy, FunctionName);
}
return Function;
}
};
/// GNU Objective-C runtime code generation. This class implements the parts of
/// Objective-C support that are specific to the GNU family of runtimes (GCC,
/// GNUstep and ObjFW).
class CGObjCGNU : public CGObjCRuntime {
protected:
/// The LLVM module into which output is inserted
llvm::Module &TheModule;
/// strut objc_super. Used for sending messages to super. This structure
/// contains the receiver (object) and the expected class.
llvm::StructType *ObjCSuperTy;
/// struct objc_super*. The type of the argument to the superclass message
/// lookup functions.
llvm::PointerType *PtrToObjCSuperTy;
/// LLVM type for selectors. Opaque pointer (i8*) unless a header declaring
/// SEL is included in a header somewhere, in which case it will be whatever
/// type is declared in that header, most likely {i8*, i8*}.
llvm::PointerType *SelectorTy;
/// LLVM i8 type. Cached here to avoid repeatedly getting it in all of the
/// places where it's used
llvm::IntegerType *Int8Ty;
/// Pointer to i8 - LLVM type of char*, for all of the places where the
/// runtime needs to deal with C strings.
llvm::PointerType *PtrToInt8Ty;
/// struct objc_protocol type
llvm::StructType *ProtocolTy;
/// Protocol * type.
llvm::PointerType *ProtocolPtrTy;
/// Instance Method Pointer type. This is a pointer to a function that takes,
/// at a minimum, an object and a selector, and is the generic type for
/// Objective-C methods. Due to differences between variadic / non-variadic
/// calling conventions, it must always be cast to the correct type before
/// actually being used.
llvm::PointerType *IMPTy;
/// Type of an untyped Objective-C object. Clang treats id as a built-in type
/// when compiling Objective-C code, so this may be an opaque pointer (i8*),
/// but if the runtime header declaring it is included then it may be a
/// pointer to a structure.
llvm::PointerType *IdTy;
/// Pointer to a pointer to an Objective-C object. Used in the new ABI
/// message lookup function and some GC-related functions.
llvm::PointerType *PtrToIdTy;
/// The clang type of id. Used when using the clang CGCall infrastructure to
/// call Objective-C methods.
CanQualType ASTIdTy;
/// LLVM type for C int type.
llvm::IntegerType *IntTy;
/// LLVM type for an opaque pointer. This is identical to PtrToInt8Ty, but is
/// used in the code to document the difference between i8* meaning a pointer
/// to a C string and i8* meaning a pointer to some opaque type.
llvm::PointerType *PtrTy;
/// LLVM type for C long type. The runtime uses this in a lot of places where
/// it should be using intptr_t, but we can't fix this without breaking
/// compatibility with GCC...
llvm::IntegerType *LongTy;
/// LLVM type for C size_t. Used in various runtime data structures.
llvm::IntegerType *SizeTy;
/// LLVM type for C intptr_t.
llvm::IntegerType *IntPtrTy;
/// LLVM type for C ptrdiff_t. Mainly used in property accessor functions.
llvm::IntegerType *PtrDiffTy;
/// LLVM type for C int*. Used for GCC-ABI-compatible non-fragile instance
/// variables.
llvm::PointerType *PtrToIntTy;
/// LLVM type for Objective-C BOOL type.
llvm::Type *BoolTy;
/// 32-bit integer type, to save us needing to look it up every time it's used.
llvm::IntegerType *Int32Ty;
/// 64-bit integer type, to save us needing to look it up every time it's used.
llvm::IntegerType *Int64Ty;
/// The type of struct objc_property.
llvm::StructType *PropertyMetadataTy;
/// Metadata kind used to tie method lookups to message sends. The GNUstep
/// runtime provides some LLVM passes that can use this to do things like
/// automatic IMP caching and speculative inlining.
unsigned msgSendMDKind;
/// Does the current target use SEH-based exceptions? False implies
/// Itanium-style DWARF unwinding.
bool usesSEHExceptions;
/// Helper to check if we are targeting a specific runtime version or later.
bool isRuntime(ObjCRuntime::Kind kind, unsigned major, unsigned minor=0) {
const ObjCRuntime &R = CGM.getLangOpts().ObjCRuntime;
return (R.getKind() == kind) &&
(R.getVersion() >= VersionTuple(major, minor));
}
std::string ManglePublicSymbol(StringRef Name) {
return (StringRef(CGM.getTriple().isOSBinFormatCOFF() ? "$_" : "._") + Name).str();
}
std::string SymbolForProtocol(Twine Name) {
return (ManglePublicSymbol("OBJC_PROTOCOL_") + Name).str();
}
std::string SymbolForProtocolRef(StringRef Name) {
return (ManglePublicSymbol("OBJC_REF_PROTOCOL_") + Name).str();
}
/// Helper function that generates a constant string and returns a pointer to
/// the start of the string. The result of this function can be used anywhere
/// where the C code specifies const char*.
llvm::Constant *MakeConstantString(StringRef Str, const char *Name = "") {
ConstantAddress Array =
CGM.GetAddrOfConstantCString(std::string(Str), Name);
return llvm::ConstantExpr::getGetElementPtr(Array.getElementType(),
Array.getPointer(), Zeros);
}
/// Emits a linkonce_odr string, whose name is the prefix followed by the
/// string value. This allows the linker to combine the strings between
/// different modules. Used for EH typeinfo names, selector strings, and a
/// few other things.
llvm::Constant *ExportUniqueString(const std::string &Str,
const std::string &prefix,
bool Private=false) {
std::string name = prefix + Str;
auto *ConstStr = TheModule.getGlobalVariable(name);
if (!ConstStr) {
llvm::Constant *value = llvm::ConstantDataArray::getString(VMContext,Str);
auto *GV = new llvm::GlobalVariable(TheModule, value->getType(), true,
llvm::GlobalValue::LinkOnceODRLinkage, value, name);
GV->setComdat(TheModule.getOrInsertComdat(name));
if (Private)
GV->setVisibility(llvm::GlobalValue::HiddenVisibility);
ConstStr = GV;
}
return llvm::ConstantExpr::getGetElementPtr(ConstStr->getValueType(),
ConstStr, Zeros);
}
/// Returns a property name and encoding string.
llvm::Constant *MakePropertyEncodingString(const ObjCPropertyDecl *PD,
const Decl *Container) {
assert(!isRuntime(ObjCRuntime::GNUstep, 2));
if (isRuntime(ObjCRuntime::GNUstep, 1, 6)) {
std::string NameAndAttributes;
std::string TypeStr =
CGM.getContext().getObjCEncodingForPropertyDecl(PD, Container);
NameAndAttributes += '\0';
NameAndAttributes += TypeStr.length() + 3;
NameAndAttributes += TypeStr;
NameAndAttributes += '\0';
NameAndAttributes += PD->getNameAsString();
return MakeConstantString(NameAndAttributes);
}
return MakeConstantString(PD->getNameAsString());
}
/// Push the property attributes into two structure fields.
void PushPropertyAttributes(ConstantStructBuilder &Fields,
const ObjCPropertyDecl *property, bool isSynthesized=true, bool
isDynamic=true) {
int attrs = property->getPropertyAttributes();
// For read-only properties, clear the copy and retain flags
if (attrs & ObjCPropertyAttribute::kind_readonly) {
attrs &= ~ObjCPropertyAttribute::kind_copy;
attrs &= ~ObjCPropertyAttribute::kind_retain;
attrs &= ~ObjCPropertyAttribute::kind_weak;
attrs &= ~ObjCPropertyAttribute::kind_strong;
}
// The first flags field has the same attribute values as clang uses internally
Fields.addInt(Int8Ty, attrs & 0xff);
attrs >>= 8;
attrs <<= 2;
// For protocol properties, synthesized and dynamic have no meaning, so we
// reuse these flags to indicate that this is a protocol property (both set
// has no meaning, as a property can't be both synthesized and dynamic)
attrs |= isSynthesized ? (1<<0) : 0;
attrs |= isDynamic ? (1<<1) : 0;
// The second field is the next four fields left shifted by two, with the
// low bit set to indicate whether the field is synthesized or dynamic.
Fields.addInt(Int8Ty, attrs & 0xff);
// Two padding fields
Fields.addInt(Int8Ty, 0);
Fields.addInt(Int8Ty, 0);
}
virtual llvm::Constant *GenerateCategoryProtocolList(const
ObjCCategoryDecl *OCD);
virtual ConstantArrayBuilder PushPropertyListHeader(ConstantStructBuilder &Fields,
int count) {
// int count;
Fields.addInt(IntTy, count);
// int size; (only in GNUstep v2 ABI.
if (isRuntime(ObjCRuntime::GNUstep, 2)) {
llvm::DataLayout td(&TheModule);
Fields.addInt(IntTy, td.getTypeSizeInBits(PropertyMetadataTy) /
CGM.getContext().getCharWidth());
}
// struct objc_property_list *next;
Fields.add(NULLPtr);
// struct objc_property properties[]
return Fields.beginArray(PropertyMetadataTy);
}
virtual void PushProperty(ConstantArrayBuilder &PropertiesArray,
const ObjCPropertyDecl *property,
const Decl *OCD,
bool isSynthesized=true, bool
isDynamic=true) {
auto Fields = PropertiesArray.beginStruct(PropertyMetadataTy);
ASTContext &Context = CGM.getContext();
Fields.add(MakePropertyEncodingString(property, OCD));
PushPropertyAttributes(Fields, property, isSynthesized, isDynamic);
auto addPropertyMethod = [&](const ObjCMethodDecl *accessor) {
if (accessor) {
std::string TypeStr = Context.getObjCEncodingForMethodDecl(accessor);
llvm::Constant *TypeEncoding = MakeConstantString(TypeStr);
Fields.add(MakeConstantString(accessor->getSelector().getAsString()));
Fields.add(TypeEncoding);
} else {
Fields.add(NULLPtr);
Fields.add(NULLPtr);
}
};
addPropertyMethod(property->getGetterMethodDecl());
addPropertyMethod(property->getSetterMethodDecl());
Fields.finishAndAddTo(PropertiesArray);
}
/// Ensures that the value has the required type, by inserting a bitcast if
/// required. This function lets us avoid inserting bitcasts that are
/// redundant.
llvm::Value* EnforceType(CGBuilderTy &B, llvm::Value *V, llvm::Type *Ty) {
if (V->getType() == Ty) return V;
return B.CreateBitCast(V, Ty);
}
Address EnforceType(CGBuilderTy &B, Address V, llvm::Type *Ty) {
if (V.getType() == Ty) return V;
return B.CreateBitCast(V, Ty);
}
// Some zeros used for GEPs in lots of places.
llvm::Constant *Zeros[2];
/// Null pointer value. Mainly used as a terminator in various arrays.
llvm::Constant *NULLPtr;
/// LLVM context.
llvm::LLVMContext &VMContext;
protected:
/// Placeholder for the class. Lots of things refer to the class before we've
/// actually emitted it. We use this alias as a placeholder, and then replace
/// it with a pointer to the class structure before finally emitting the
/// module.
llvm::GlobalAlias *ClassPtrAlias;
/// Placeholder for the metaclass. Lots of things refer to the class before
/// we've / actually emitted it. We use this alias as a placeholder, and then
/// replace / it with a pointer to the metaclass structure before finally
/// emitting the / module.
llvm::GlobalAlias *MetaClassPtrAlias;
/// All of the classes that have been generated for this compilation units.
std::vector<llvm::Constant*> Classes;
/// All of the categories that have been generated for this compilation units.
std::vector<llvm::Constant*> Categories;
/// All of the Objective-C constant strings that have been generated for this
/// compilation units.
std::vector<llvm::Constant*> ConstantStrings;
/// Map from string values to Objective-C constant strings in the output.
/// Used to prevent emitting Objective-C strings more than once. This should
/// not be required at all - CodeGenModule should manage this list.
llvm::StringMap<llvm::Constant*> ObjCStrings;
/// All of the protocols that have been declared.
llvm::StringMap<llvm::Constant*> ExistingProtocols;
/// For each variant of a selector, we store the type encoding and a
/// placeholder value. For an untyped selector, the type will be the empty
/// string. Selector references are all done via the module's selector table,
/// so we create an alias as a placeholder and then replace it with the real
/// value later.
typedef std::pair<std::string, llvm::GlobalAlias*> TypedSelector;
/// Type of the selector map. This is roughly equivalent to the structure
/// used in the GNUstep runtime, which maintains a list of all of the valid
/// types for a selector in a table.
typedef llvm::DenseMap<Selector, SmallVector<TypedSelector, 2> >
SelectorMap;
/// A map from selectors to selector types. This allows us to emit all
/// selectors of the same name and type together.
SelectorMap SelectorTable;
/// Selectors related to memory management. When compiling in GC mode, we
/// omit these.
Selector RetainSel, ReleaseSel, AutoreleaseSel;
/// Runtime functions used for memory management in GC mode. Note that clang
/// supports code generation for calling these functions, but neither GNU
/// runtime actually supports this API properly yet.
LazyRuntimeFunction IvarAssignFn, StrongCastAssignFn, MemMoveFn, WeakReadFn,
WeakAssignFn, GlobalAssignFn;
typedef std::pair<std::string, std::string> ClassAliasPair;
/// All classes that have aliases set for them.
std::vector<ClassAliasPair> ClassAliases;
protected:
/// Function used for throwing Objective-C exceptions.
LazyRuntimeFunction ExceptionThrowFn;
/// Function used for rethrowing exceptions, used at the end of \@finally or
/// \@synchronize blocks.
LazyRuntimeFunction ExceptionReThrowFn;
/// Function called when entering a catch function. This is required for
/// differentiating Objective-C exceptions and foreign exceptions.
LazyRuntimeFunction EnterCatchFn;
/// Function called when exiting from a catch block. Used to do exception
/// cleanup.
LazyRuntimeFunction ExitCatchFn;
/// Function called when entering an \@synchronize block. Acquires the lock.
LazyRuntimeFunction SyncEnterFn;
/// Function called when exiting an \@synchronize block. Releases the lock.
LazyRuntimeFunction SyncExitFn;
private:
/// Function called if fast enumeration detects that the collection is
/// modified during the update.
LazyRuntimeFunction EnumerationMutationFn;
/// Function for implementing synthesized property getters that return an
/// object.
LazyRuntimeFunction GetPropertyFn;
/// Function for implementing synthesized property setters that return an
/// object.
LazyRuntimeFunction SetPropertyFn;
/// Function used for non-object declared property getters.
LazyRuntimeFunction GetStructPropertyFn;
/// Function used for non-object declared property setters.
LazyRuntimeFunction SetStructPropertyFn;
protected:
/// The version of the runtime that this class targets. Must match the
/// version in the runtime.
int RuntimeVersion;
/// The version of the protocol class. Used to differentiate between ObjC1
/// and ObjC2 protocols. Objective-C 1 protocols can not contain optional
/// components and can not contain declared properties. We always emit
/// Objective-C 2 property structures, but we have to pretend that they're
/// Objective-C 1 property structures when targeting the GCC runtime or it
/// will abort.
const int ProtocolVersion;
/// The version of the class ABI. This value is used in the class structure
/// and indicates how various fields should be interpreted.
const int ClassABIVersion;
/// Generates an instance variable list structure. This is a structure
/// containing a size and an array of structures containing instance variable
/// metadata. This is used purely for introspection in the fragile ABI. In
/// the non-fragile ABI, it's used for instance variable fixup.
virtual llvm::Constant *GenerateIvarList(ArrayRef<llvm::Constant *> IvarNames,
ArrayRef<llvm::Constant *> IvarTypes,
ArrayRef<llvm::Constant *> IvarOffsets,
ArrayRef<llvm::Constant *> IvarAlign,
ArrayRef<Qualifiers::ObjCLifetime> IvarOwnership);
/// Generates a method list structure. This is a structure containing a size
/// and an array of structures containing method metadata.
///
/// This structure is used by both classes and categories, and contains a next
/// pointer allowing them to be chained together in a linked list.
llvm::Constant *GenerateMethodList(StringRef ClassName,
StringRef CategoryName,
ArrayRef<const ObjCMethodDecl*> Methods,
bool isClassMethodList);
/// Emits an empty protocol. This is used for \@protocol() where no protocol
/// is found. The runtime will (hopefully) fix up the pointer to refer to the
/// real protocol.
virtual llvm::Constant *GenerateEmptyProtocol(StringRef ProtocolName);
/// Generates a list of property metadata structures. This follows the same
/// pattern as method and instance variable metadata lists.
llvm::Constant *GeneratePropertyList(const Decl *Container,
const ObjCContainerDecl *OCD,
bool isClassProperty=false,
bool protocolOptionalProperties=false);
/// Generates a list of referenced protocols. Classes, categories, and
/// protocols all use this structure.
llvm::Constant *GenerateProtocolList(ArrayRef<std::string> Protocols);
/// To ensure that all protocols are seen by the runtime, we add a category on
/// a class defined in the runtime, declaring no methods, but adopting the
/// protocols. This is a horribly ugly hack, but it allows us to collect all
/// of the protocols without changing the ABI.
void GenerateProtocolHolderCategory();
/// Generates a class structure.
llvm::Constant *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=false);
/// Generates a method list. This is used by protocols to define the required
/// and optional methods.
virtual llvm::Constant *GenerateProtocolMethodList(
ArrayRef<const ObjCMethodDecl*> Methods);
/// Emits optional and required method lists.
template<class T>
void EmitProtocolMethodList(T &&Methods, llvm::Constant *&Required,
llvm::Constant *&Optional) {
SmallVector<const ObjCMethodDecl*, 16> RequiredMethods;
SmallVector<const ObjCMethodDecl*, 16> OptionalMethods;
for (const auto *I : Methods)
if (I->isOptional())
OptionalMethods.push_back(I);
else
RequiredMethods.push_back(I);
Required = GenerateProtocolMethodList(RequiredMethods);
Optional = GenerateProtocolMethodList(OptionalMethods);
}
/// Returns a selector with the specified type encoding. An empty string is
/// used to return an untyped selector (with the types field set to NULL).
virtual llvm::Value *GetTypedSelector(CodeGenFunction &CGF, Selector Sel,
const std::string &TypeEncoding);
/// Returns the name of ivar offset variables. In the GNUstep v1 ABI, this
/// contains the class and ivar names, in the v2 ABI this contains the type
/// encoding as well.
virtual std::string GetIVarOffsetVariableName(const ObjCInterfaceDecl *ID,
const ObjCIvarDecl *Ivar) {
const std::string Name = "__objc_ivar_offset_" + ID->getNameAsString()
+ '.' + Ivar->getNameAsString();
return Name;
}
/// Returns the variable used to store the offset of an instance variable.
llvm::GlobalVariable *ObjCIvarOffsetVariable(const ObjCInterfaceDecl *ID,
const ObjCIvarDecl *Ivar);
/// Emits a reference to a class. This allows the linker to object if there
/// is no class of the matching name.
void EmitClassRef(const std::string &className);
/// Emits a pointer to the named class
virtual llvm::Value *GetClassNamed(CodeGenFunction &CGF,
const std::string &Name, bool isWeak);
/// Looks up the method for sending a message to the specified object. This
/// mechanism differs between the GCC and GNU runtimes, so this method must be
/// overridden in subclasses.
virtual llvm::Value *LookupIMP(CodeGenFunction &CGF,
llvm::Value *&Receiver,
llvm::Value *cmd,
llvm::MDNode *node,
MessageSendInfo &MSI) = 0;
/// Looks up the method for sending a message to a superclass. This
/// mechanism differs between the GCC and GNU runtimes, so this method must
/// be overridden in subclasses.
virtual llvm::Value *LookupIMPSuper(CodeGenFunction &CGF,
Address ObjCSuper,
llvm::Value *cmd,
MessageSendInfo &MSI) = 0;
/// Libobjc2 uses a bitfield representation where small(ish) bitfields are
/// stored in a 64-bit value with the low bit set to 1 and the remaining 63
/// bits set to their values, LSB first, while larger ones are stored in a
/// structure of this / form:
///
/// struct { int32_t length; int32_t values[length]; };
///
/// The values in the array are stored in host-endian format, with the least
/// significant bit being assumed to come first in the bitfield. Therefore,
/// a bitfield with the 64th bit set will be (int64_t)&{ 2, [0, 1<<31] },
/// while a bitfield / with the 63rd bit set will be 1<<64.
llvm::Constant *MakeBitField(ArrayRef<bool> bits);
public:
CGObjCGNU(CodeGenModule &cgm, unsigned runtimeABIVersion,
unsigned protocolClassVersion, unsigned classABI=1);
ConstantAddress GenerateConstantString(const StringLiteral *) override;
RValue
GenerateMessageSend(CodeGenFunction &CGF, ReturnValueSlot Return,
QualType ResultType, Selector Sel,
llvm::Value *Receiver, const CallArgList &CallArgs,
const ObjCInterfaceDecl *Class,
const ObjCMethodDecl *Method) override;
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) override;
llvm::Value *GetClass(CodeGenFunction &CGF,
const ObjCInterfaceDecl *OID) override;
llvm::Value *GetSelector(CodeGenFunction &CGF, Selector Sel) override;
Address GetAddrOfSelector(CodeGenFunction &CGF, Selector Sel) override;
llvm::Value *GetSelector(CodeGenFunction &CGF,
const ObjCMethodDecl *Method) override;
virtual llvm::Constant *GetConstantSelector(Selector Sel,
const std::string &TypeEncoding) {
llvm_unreachable("Runtime unable to generate constant selector");
}
llvm::Constant *GetConstantSelector(const ObjCMethodDecl *M) {
return GetConstantSelector(M->getSelector(),
CGM.getContext().getObjCEncodingForMethodDecl(M));
}
llvm::Constant *GetEHType(QualType T) override;
llvm::Function *GenerateMethod(const ObjCMethodDecl *OMD,
const ObjCContainerDecl *CD) override;
void GenerateDirectMethodPrologue(CodeGenFunction &CGF, llvm::Function *Fn,
const ObjCMethodDecl *OMD,
const ObjCContainerDecl *CD) override;
void GenerateCategory(const ObjCCategoryImplDecl *CMD) override;
void GenerateClass(const ObjCImplementationDecl *ClassDecl) override;
void RegisterAlias(const ObjCCompatibleAliasDecl *OAD) override;
llvm::Value *GenerateProtocolRef(CodeGenFunction &CGF,
const ObjCProtocolDecl *PD) override;
void GenerateProtocol(const ObjCProtocolDecl *PD) override;
virtual llvm::Constant *GenerateProtocolRef(const ObjCProtocolDecl *PD);
llvm::Constant *GetOrEmitProtocol(const ObjCProtocolDecl *PD) override {
return GenerateProtocolRef(PD);
}
llvm::Function *ModuleInitFunction() override;
llvm::FunctionCallee GetPropertyGetFunction() override;
llvm::FunctionCallee GetPropertySetFunction() override;
llvm::FunctionCallee GetOptimizedPropertySetFunction(bool atomic,
bool copy) override;
llvm::FunctionCallee GetSetStructFunction() override;
llvm::FunctionCallee GetGetStructFunction() override;
llvm::FunctionCallee GetCppAtomicObjectGetFunction() override;
llvm::FunctionCallee GetCppAtomicObjectSetFunction() override;
llvm::FunctionCallee EnumerationMutationFunction() override;
void EmitTryStmt(CodeGenFunction &CGF,
const ObjCAtTryStmt &S) override;
void EmitSynchronizedStmt(CodeGenFunction &CGF,
const ObjCAtSynchronizedStmt &S) override;
void EmitThrowStmt(CodeGenFunction &CGF,
const ObjCAtThrowStmt &S,
bool ClearInsertionPoint=true) override;
llvm::Value * EmitObjCWeakRead(CodeGenFunction &CGF,
Address AddrWeakObj) override;
void EmitObjCWeakAssign(CodeGenFunction &CGF,
llvm::Value *src, Address dst) override;
void EmitObjCGlobalAssign(CodeGenFunction &CGF,
llvm::Value *src, Address dest,
bool threadlocal=false) override;
void EmitObjCIvarAssign(CodeGenFunction &CGF, llvm::Value *src,
Address dest, llvm::Value *ivarOffset) override;
void EmitObjCStrongCastAssign(CodeGenFunction &CGF,
llvm::Value *src, Address dest) override;
void EmitGCMemmoveCollectable(CodeGenFunction &CGF, Address DestPtr,
Address SrcPtr,
llvm::Value *Size) override;
LValue EmitObjCValueForIvar(CodeGenFunction &CGF, QualType ObjectTy,
llvm::Value *BaseValue, const ObjCIvarDecl *Ivar,
unsigned CVRQualifiers) override;
llvm::Value *EmitIvarOffset(CodeGenFunction &CGF,
const ObjCInterfaceDecl *Interface,
const ObjCIvarDecl *Ivar) override;
llvm::Value *EmitNSAutoreleasePoolClassRef(CodeGenFunction &CGF) override;
llvm::Constant *BuildGCBlockLayout(CodeGenModule &CGM,
const CGBlockInfo &blockInfo) override {
return NULLPtr;
}
llvm::Constant *BuildRCBlockLayout(CodeGenModule &CGM,
const CGBlockInfo &blockInfo) override {
return NULLPtr;
}
llvm::Constant *BuildByrefLayout(CodeGenModule &CGM, QualType T) override {
return NULLPtr;
}
};
/// Class representing the legacy GCC Objective-C ABI. This is the default when
/// -fobjc-nonfragile-abi is not specified.
///
/// The GCC ABI target actually generates code that is approximately compatible
/// with the new GNUstep runtime ABI, but refrains from using any features that
/// would not work with the GCC runtime. For example, clang always generates
/// the extended form of the class structure, and the extra fields are simply
/// ignored by GCC libobjc.
class CGObjCGCC : public CGObjCGNU {
/// The GCC ABI message lookup function. Returns an IMP pointing to the
/// method implementation for this message.
LazyRuntimeFunction MsgLookupFn;
/// The GCC ABI superclass message lookup function. Takes a pointer to a
/// structure describing the receiver and the class, and a selector as
/// arguments. Returns the IMP for the corresponding method.
LazyRuntimeFunction MsgLookupSuperFn;
protected:
llvm::Value *LookupIMP(CodeGenFunction &CGF, llvm::Value *&Receiver,
llvm::Value *cmd, llvm::MDNode *node,
MessageSendInfo &MSI) override {
CGBuilderTy &Builder = CGF.Builder;
llvm::Value *args[] = {
EnforceType(Builder, Receiver, IdTy),
EnforceType(Builder, cmd, SelectorTy) };
llvm::CallBase *imp = CGF.EmitRuntimeCallOrInvoke(MsgLookupFn, args);
imp->setMetadata(msgSendMDKind, node);
return imp;
}
llvm::Value *LookupIMPSuper(CodeGenFunction &CGF, Address ObjCSuper,
llvm::Value *cmd, MessageSendInfo &MSI) override {
CGBuilderTy &Builder = CGF.Builder;
llvm::Value *lookupArgs[] = {EnforceType(Builder, ObjCSuper,
PtrToObjCSuperTy).getPointer(), cmd};
return CGF.EmitNounwindRuntimeCall(MsgLookupSuperFn, lookupArgs);
}
public:
CGObjCGCC(CodeGenModule &Mod) : CGObjCGNU(Mod, 8, 2) {
// IMP objc_msg_lookup(id, SEL);
MsgLookupFn.init(&CGM, "objc_msg_lookup", IMPTy, IdTy, SelectorTy);
// IMP objc_msg_lookup_super(struct objc_super*, SEL);
MsgLookupSuperFn.init(&CGM, "objc_msg_lookup_super", IMPTy,
PtrToObjCSuperTy, SelectorTy);
}
};
/// Class used when targeting the new GNUstep runtime ABI.
class CGObjCGNUstep : public CGObjCGNU {
/// The slot lookup function. Returns a pointer to a cacheable structure
/// that contains (among other things) the IMP.
LazyRuntimeFunction SlotLookupFn;
/// The GNUstep ABI superclass message lookup function. Takes a pointer to
/// a structure describing the receiver and the class, and a selector as
/// arguments. Returns the slot for the corresponding method. Superclass
/// message lookup rarely changes, so this is a good caching opportunity.
LazyRuntimeFunction SlotLookupSuperFn;
/// Specialised function for setting atomic retain properties
LazyRuntimeFunction SetPropertyAtomic;
/// Specialised function for setting atomic copy properties
LazyRuntimeFunction SetPropertyAtomicCopy;
/// Specialised function for setting nonatomic retain properties
LazyRuntimeFunction SetPropertyNonAtomic;
/// Specialised function for setting nonatomic copy properties
LazyRuntimeFunction SetPropertyNonAtomicCopy;
/// Function to perform atomic copies of C++ objects with nontrivial copy
/// constructors from Objective-C ivars.
LazyRuntimeFunction CxxAtomicObjectGetFn;
/// Function to perform atomic copies of C++ objects with nontrivial copy
/// constructors to Objective-C ivars.
LazyRuntimeFunction CxxAtomicObjectSetFn;
/// Type of an slot structure pointer. This is returned by the various
/// lookup functions.
llvm::Type *SlotTy;
public:
llvm::Constant *GetEHType(QualType T) override;
protected:
llvm::Value *LookupIMP(CodeGenFunction &CGF, llvm::Value *&Receiver,
llvm::Value *cmd, llvm::MDNode *node,
MessageSendInfo &MSI) override {
CGBuilderTy &Builder = CGF.Builder;
llvm::FunctionCallee LookupFn = SlotLookupFn;
// Store the receiver on the stack so that we can reload it later
Address ReceiverPtr =
CGF.CreateTempAlloca(Receiver->getType(), CGF.getPointerAlign());
Builder.CreateStore(Receiver, ReceiverPtr);
llvm::Value *self;
if (isa<ObjCMethodDecl>(CGF.CurCodeDecl)) {
self = CGF.LoadObjCSelf();
} else {
self = llvm::ConstantPointerNull::get(IdTy);
}
// The lookup function is guaranteed not to capture the receiver pointer.
if (auto *LookupFn2 = dyn_cast<llvm::Function>(LookupFn.getCallee()))
LookupFn2->addParamAttr(0, llvm::Attribute::NoCapture);
llvm::Value *args[] = {
EnforceType(Builder, ReceiverPtr.getPointer(), PtrToIdTy),
EnforceType(Builder, cmd, SelectorTy),
EnforceType(Builder, self, IdTy) };
llvm::CallBase *slot = CGF.EmitRuntimeCallOrInvoke(LookupFn, args);
slot->setOnlyReadsMemory();
slot->setMetadata(msgSendMDKind, node);
// Load the imp from the slot
llvm::Value *imp = Builder.CreateAlignedLoad(
IMPTy, Builder.CreateStructGEP(nullptr, slot, 4),
CGF.getPointerAlign());
// The lookup function may have changed the receiver, so make sure we use
// the new one.
Receiver = Builder.CreateLoad(ReceiverPtr, true);
return imp;
}
llvm::Value *LookupIMPSuper(CodeGenFunction &CGF, Address ObjCSuper,
llvm::Value *cmd,
MessageSendInfo &MSI) override {
CGBuilderTy &Builder = CGF.Builder;
llvm::Value *lookupArgs[] = {ObjCSuper.getPointer(), cmd};
llvm::CallInst *slot =
CGF.EmitNounwindRuntimeCall(SlotLookupSuperFn, lookupArgs);
slot->setOnlyReadsMemory();
return Builder.CreateAlignedLoad(
IMPTy, Builder.CreateStructGEP(nullptr, slot, 4),
CGF.getPointerAlign());
}
public:
CGObjCGNUstep(CodeGenModule &Mod) : CGObjCGNUstep(Mod, 9, 3, 1) {}
CGObjCGNUstep(CodeGenModule &Mod, unsigned ABI, unsigned ProtocolABI,
unsigned ClassABI) :
CGObjCGNU(Mod, ABI, ProtocolABI, ClassABI) {
const ObjCRuntime &R = CGM.getLangOpts().ObjCRuntime;
llvm::StructType *SlotStructTy =
llvm::StructType::get(PtrTy, PtrTy, PtrTy, IntTy, IMPTy);
SlotTy = llvm::PointerType::getUnqual(SlotStructTy);
// Slot_t objc_msg_lookup_sender(id *receiver, SEL selector, id sender);
SlotLookupFn.init(&CGM, "objc_msg_lookup_sender", SlotTy, PtrToIdTy,
SelectorTy, IdTy);
// Slot_t objc_slot_lookup_super(struct objc_super*, SEL);
SlotLookupSuperFn.init(&CGM, "objc_slot_lookup_super", SlotTy,
PtrToObjCSuperTy, SelectorTy);
// If we're in ObjC++ mode, then we want to make
if (usesSEHExceptions) {
llvm::Type *VoidTy = llvm::Type::getVoidTy(VMContext);
// void objc_exception_rethrow(void)
ExceptionReThrowFn.init(&CGM, "objc_exception_rethrow", VoidTy);
} else if (CGM.getLangOpts().CPlusPlus) {
llvm::Type *VoidTy = llvm::Type::getVoidTy(VMContext);
// void *__cxa_begin_catch(void *e)
EnterCatchFn.init(&CGM, "__cxa_begin_catch", PtrTy, PtrTy);
// void __cxa_end_catch(void)
ExitCatchFn.init(&CGM, "__cxa_end_catch", VoidTy);
// void _Unwind_Resume_or_Rethrow(void*)
ExceptionReThrowFn.init(&CGM, "_Unwind_Resume_or_Rethrow", VoidTy,
PtrTy);
} else if (R.getVersion() >= VersionTuple(1, 7)) {
llvm::Type *VoidTy = llvm::Type::getVoidTy(VMContext);
// id objc_begin_catch(void *e)
EnterCatchFn.init(&CGM, "objc_begin_catch", IdTy, PtrTy);
// void objc_end_catch(void)
ExitCatchFn.init(&CGM, "objc_end_catch", VoidTy);
// void _Unwind_Resume_or_Rethrow(void*)
ExceptionReThrowFn.init(&CGM, "objc_exception_rethrow", VoidTy, PtrTy);
}
llvm::Type *VoidTy = llvm::Type::getVoidTy(VMContext);
SetPropertyAtomic.init(&CGM, "objc_setProperty_atomic", VoidTy, IdTy,
SelectorTy, IdTy, PtrDiffTy);
SetPropertyAtomicCopy.init(&CGM, "objc_setProperty_atomic_copy", VoidTy,
IdTy, SelectorTy, IdTy, PtrDiffTy);
SetPropertyNonAtomic.init(&CGM, "objc_setProperty_nonatomic", VoidTy,
IdTy, SelectorTy, IdTy, PtrDiffTy);
SetPropertyNonAtomicCopy.init(&CGM, "objc_setProperty_nonatomic_copy",
VoidTy, IdTy, SelectorTy, IdTy, PtrDiffTy);
// void objc_setCppObjectAtomic(void *dest, const void *src, void
// *helper);
CxxAtomicObjectSetFn.init(&CGM, "objc_setCppObjectAtomic", VoidTy, PtrTy,
PtrTy, PtrTy);
// void objc_getCppObjectAtomic(void *dest, const void *src, void
// *helper);
CxxAtomicObjectGetFn.init(&CGM, "objc_getCppObjectAtomic", VoidTy, PtrTy,
PtrTy, PtrTy);
}
llvm::FunctionCallee GetCppAtomicObjectGetFunction() override {
// The optimised functions were added in version 1.7 of the GNUstep
// runtime.
assert (CGM.getLangOpts().ObjCRuntime.getVersion() >=
VersionTuple(1, 7));
return CxxAtomicObjectGetFn;
}
llvm::FunctionCallee GetCppAtomicObjectSetFunction() override {
// The optimised functions were added in version 1.7 of the GNUstep
// runtime.
assert (CGM.getLangOpts().ObjCRuntime.getVersion() >=
VersionTuple(1, 7));
return CxxAtomicObjectSetFn;
}
llvm::FunctionCallee GetOptimizedPropertySetFunction(bool atomic,
bool copy) override {
// The optimised property functions omit the GC check, and so are not
// safe to use in GC mode. The standard functions are fast in GC mode,
// so there is less advantage in using them.
assert ((CGM.getLangOpts().getGC() == LangOptions::NonGC));
// The optimised functions were added in version 1.7 of the GNUstep
// runtime.
assert (CGM.getLangOpts().ObjCRuntime.getVersion() >=
VersionTuple(1, 7));
if (atomic) {
if (copy) return SetPropertyAtomicCopy;
return SetPropertyAtomic;
}
return copy ? SetPropertyNonAtomicCopy : SetPropertyNonAtomic;
}
};
/// GNUstep Objective-C ABI version 2 implementation.
/// This is the ABI that provides a clean break with the legacy GCC ABI and
/// cleans up a number of things that were added to work around 1980s linkers.
class CGObjCGNUstep2 : public CGObjCGNUstep {
enum SectionKind
{
SelectorSection = 0,
ClassSection,
ClassReferenceSection,
CategorySection,
ProtocolSection,
ProtocolReferenceSection,
ClassAliasSection,
ConstantStringSection
};
static const char *const SectionsBaseNames[8];
static const char *const PECOFFSectionsBaseNames[8];
template<SectionKind K>
std::string sectionName() {
if (CGM.getTriple().isOSBinFormatCOFF()) {
std::string name(PECOFFSectionsBaseNames[K]);
name += "$m";
return name;
}
return SectionsBaseNames[K];
}
/// The GCC ABI superclass message lookup function. Takes a pointer to a
/// structure describing the receiver and the class, and a selector as
/// arguments. Returns the IMP for the corresponding method.
LazyRuntimeFunction MsgLookupSuperFn;
/// A flag indicating if we've emitted at least one protocol.
/// If we haven't, then we need to emit an empty protocol, to ensure that the
/// __start__objc_protocols and __stop__objc_protocols sections exist.
bool EmittedProtocol = false;
/// A flag indicating if we've emitted at least one protocol reference.
/// If we haven't, then we need to emit an empty protocol, to ensure that the
/// __start__objc_protocol_refs and __stop__objc_protocol_refs sections
/// exist.
bool EmittedProtocolRef = false;
/// A flag indicating if we've emitted at least one class.
/// If we haven't, then we need to emit an empty protocol, to ensure that the
/// __start__objc_classes and __stop__objc_classes sections / exist.
bool EmittedClass = false;
/// Generate the name of a symbol for a reference to a class. Accesses to
/// classes should be indirected via this.
typedef std::pair<std::string, std::pair<llvm::Constant*, int>> EarlyInitPair;
std::vector<EarlyInitPair> EarlyInitList;
std::string SymbolForClassRef(StringRef Name, bool isWeak) {
if (isWeak)
return (ManglePublicSymbol("OBJC_WEAK_REF_CLASS_") + Name).str();
else
return (ManglePublicSymbol("OBJC_REF_CLASS_") + Name).str();
}
/// Generate the name of a class symbol.
std::string SymbolForClass(StringRef Name) {
return (ManglePublicSymbol("OBJC_CLASS_") + Name).str();
}
void CallRuntimeFunction(CGBuilderTy &B, StringRef FunctionName,
ArrayRef<llvm::Value*> Args) {
SmallVector<llvm::Type *,8> Types;
for (auto *Arg : Args)
Types.push_back(Arg->getType());
llvm::FunctionType *FT = llvm::FunctionType::get(B.getVoidTy(), Types,
false);
llvm::FunctionCallee Fn = CGM.CreateRuntimeFunction(FT, FunctionName);
B.CreateCall(Fn, Args);
}
ConstantAddress GenerateConstantString(const StringLiteral *SL) override {
auto Str = SL->getString();
CharUnits Align = CGM.getPointerAlign();
// Look for an existing one
llvm::StringMap<llvm::Constant*>::iterator old = ObjCStrings.find(Str);
if (old != ObjCStrings.end())
return ConstantAddress(old->getValue(), Align);
bool isNonASCII = SL->containsNonAscii();
auto LiteralLength = SL->getLength();
if ((CGM.getTarget().getPointerWidth(0) == 64) &&
(LiteralLength < 9) && !isNonASCII) {
// Tiny strings are only used on 64-bit platforms. They store 8 7-bit
// ASCII characters in the high 56 bits, followed by a 4-bit length and a
// 3-bit tag (which is always 4).
uint64_t str = 0;
// Fill in the characters
for (unsigned i=0 ; i<LiteralLength ; i++)
str |= ((uint64_t)SL->getCodeUnit(i)) << ((64 - 4 - 3) - (i*7));
// Fill in the length
str |= LiteralLength << 3;
// Set the tag
str |= 4;
auto *ObjCStr = llvm::ConstantExpr::getIntToPtr(
llvm::ConstantInt::get(Int64Ty, str), IdTy);
ObjCStrings[Str] = ObjCStr;
return ConstantAddress(ObjCStr, Align);
}
StringRef StringClass = CGM.getLangOpts().ObjCConstantStringClass;
if (StringClass.empty()) StringClass = "NSConstantString";
std::string Sym = SymbolForClass(StringClass);
llvm::Constant *isa = TheModule.getNamedGlobal(Sym);
if (!isa) {
isa = new llvm::GlobalVariable(TheModule, IdTy, /* isConstant */false,
llvm::GlobalValue::ExternalLinkage, nullptr, Sym);
if (CGM.getTriple().isOSBinFormatCOFF()) {
cast<llvm::GlobalValue>(isa)->setDLLStorageClass(llvm::GlobalValue::DLLImportStorageClass);
}
} else if (isa->getType() != PtrToIdTy)
isa = llvm::ConstantExpr::getBitCast(isa, PtrToIdTy);
// struct
// {
// Class isa;
// uint32_t flags;
// uint32_t length; // Number of codepoints
// uint32_t size; // Number of bytes
// uint32_t hash;
// const char *data;
// };
ConstantInitBuilder Builder(CGM);
auto Fields = Builder.beginStruct();
if (!CGM.getTriple().isOSBinFormatCOFF()) {
Fields.add(isa);
} else {
Fields.addNullPointer(PtrTy);
}
// For now, all non-ASCII strings are represented as UTF-16. As such, the
// number of bytes is simply double the number of UTF-16 codepoints. In
// ASCII strings, the number of bytes is equal to the number of non-ASCII
// codepoints.
if (isNonASCII) {
unsigned NumU8CodeUnits = Str.size();
// A UTF-16 representation of a unicode string contains at most the same
// number of code units as a UTF-8 representation. Allocate that much
// space, plus one for the final null character.
SmallVector<llvm::UTF16, 128> ToBuf(NumU8CodeUnits + 1);
const llvm::UTF8 *FromPtr = (const llvm::UTF8 *)Str.data();
llvm::UTF16 *ToPtr = &ToBuf[0];
(void)llvm::ConvertUTF8toUTF16(&FromPtr, FromPtr + NumU8CodeUnits,
&ToPtr, ToPtr + NumU8CodeUnits, llvm::strictConversion);
uint32_t StringLength = ToPtr - &ToBuf[0];
// Add null terminator
*ToPtr = 0;
// Flags: 2 indicates UTF-16 encoding
Fields.addInt(Int32Ty, 2);
// Number of UTF-16 codepoints
Fields.addInt(Int32Ty, StringLength);
// Number of bytes
Fields.addInt(Int32Ty, StringLength * 2);
// Hash. Not currently initialised by the compiler.
Fields.addInt(Int32Ty, 0);
// pointer to the data string.
auto Arr = llvm::makeArrayRef(&ToBuf[0], ToPtr+1);
auto *C = llvm::ConstantDataArray::get(VMContext, Arr);
auto *Buffer = new llvm::GlobalVariable(TheModule, C->getType(),
/*isConstant=*/true, llvm::GlobalValue::PrivateLinkage, C, ".str");
Buffer->setUnnamedAddr(llvm::GlobalValue::UnnamedAddr::Global);
Fields.add(Buffer);
} else {
// Flags: 0 indicates ASCII encoding
Fields.addInt(Int32Ty, 0);
// Number of UTF-16 codepoints, each ASCII byte is a UTF-16 codepoint
Fields.addInt(Int32Ty, Str.size());
// Number of bytes
Fields.addInt(Int32Ty, Str.size());
// Hash. Not currently initialised by the compiler.
Fields.addInt(Int32Ty, 0);
// Data pointer
Fields.add(MakeConstantString(Str));
}
std::string StringName;
bool isNamed = !isNonASCII;
if (isNamed) {
StringName = ".objc_str_";
for (int i=0,e=Str.size() ; i<e ; ++i) {
unsigned char c = Str[i];
if (isalnum(c))
StringName += c;
else if (c == ' ')
StringName += '_';
else {
isNamed = false;
break;
}
}
}
auto *ObjCStrGV =
Fields.finishAndCreateGlobal(
isNamed ? StringRef(StringName) : ".objc_string",
Align, false, isNamed ? llvm::GlobalValue::LinkOnceODRLinkage
: llvm::GlobalValue::PrivateLinkage);
ObjCStrGV->setSection(sectionName<ConstantStringSection>());
if (isNamed) {
ObjCStrGV->setComdat(TheModule.getOrInsertComdat(StringName));
ObjCStrGV->setVisibility(llvm::GlobalValue::HiddenVisibility);
}
if (CGM.getTriple().isOSBinFormatCOFF()) {
std::pair<llvm::Constant*, int> v{ObjCStrGV, 0};
EarlyInitList.emplace_back(Sym, v);
}
llvm::Constant *ObjCStr = llvm::ConstantExpr::getBitCast(ObjCStrGV, IdTy);
ObjCStrings[Str] = ObjCStr;
ConstantStrings.push_back(ObjCStr);
return ConstantAddress(ObjCStr, Align);
}
void PushProperty(ConstantArrayBuilder &PropertiesArray,
const ObjCPropertyDecl *property,
const Decl *OCD,
bool isSynthesized=true, bool
isDynamic=true) override {
// struct objc_property
// {
// const char *name;
// const char *attributes;
// const char *type;
// SEL getter;
// SEL setter;
// };
auto Fields = PropertiesArray.beginStruct(PropertyMetadataTy);
ASTContext &Context = CGM.getContext();
Fields.add(MakeConstantString(property->getNameAsString()));
std::string TypeStr =
CGM.getContext().getObjCEncodingForPropertyDecl(property, OCD);
Fields.add(MakeConstantString(TypeStr));
std::string typeStr;
Context.getObjCEncodingForType(property->getType(), typeStr);
Fields.add(MakeConstantString(typeStr));
auto addPropertyMethod = [&](const ObjCMethodDecl *accessor) {
if (accessor) {
std::string TypeStr = Context.getObjCEncodingForMethodDecl(accessor);
Fields.add(GetConstantSelector(accessor->getSelector(), TypeStr));
} else {
Fields.add(NULLPtr);
}
};
addPropertyMethod(property->getGetterMethodDecl());
addPropertyMethod(property->getSetterMethodDecl());
Fields.finishAndAddTo(PropertiesArray);
}
llvm::Constant *
GenerateProtocolMethodList(ArrayRef<const ObjCMethodDecl*> Methods) override {
// struct objc_protocol_method_description
// {
// SEL selector;
// const char *types;
// };
llvm::StructType *ObjCMethodDescTy =
llvm::StructType::get(CGM.getLLVMContext(),
{ PtrToInt8Ty, PtrToInt8Ty });
ASTContext &Context = CGM.getContext();
ConstantInitBuilder Builder(CGM);
// struct objc_protocol_method_description_list
// {
// int count;
// int size;
// struct objc_protocol_method_description methods[];
// };
auto MethodList = Builder.beginStruct();
// int count;
MethodList.addInt(IntTy, Methods.size());
// int size; // sizeof(struct objc_method_description)
llvm::DataLayout td(&TheModule);
MethodList.addInt(IntTy, td.getTypeSizeInBits(ObjCMethodDescTy) /
CGM.getContext().getCharWidth());
// struct objc_method_description[]
auto MethodArray = MethodList.beginArray(ObjCMethodDescTy);
for (auto *M : Methods) {
auto Method = MethodArray.beginStruct(ObjCMethodDescTy);
Method.add(CGObjCGNU::GetConstantSelector(M));
Method.add(GetTypeString(Context.getObjCEncodingForMethodDecl(M, true)));
Method.finishAndAddTo(MethodArray);
}
MethodArray.finishAndAddTo(MethodList);
return MethodList.finishAndCreateGlobal(".objc_protocol_method_list",
CGM.getPointerAlign());
}
llvm::Constant *GenerateCategoryProtocolList(const ObjCCategoryDecl *OCD)
override {
const auto &ReferencedProtocols = OCD->getReferencedProtocols();
auto RuntimeProtocols = GetRuntimeProtocolList(ReferencedProtocols.begin(),
ReferencedProtocols.end());
SmallVector<llvm::Constant *, 16> Protocols;
for (const auto *PI : RuntimeProtocols)
Protocols.push_back(
llvm::ConstantExpr::getBitCast(GenerateProtocolRef(PI),
ProtocolPtrTy));
return GenerateProtocolList(Protocols);
}
llvm::Value *LookupIMPSuper(CodeGenFunction &CGF, Address ObjCSuper,
llvm::Value *cmd, MessageSendInfo &MSI) override {
// Don't access the slot unless we're trying to cache the result.
CGBuilderTy &Builder = CGF.Builder;
llvm::Value *lookupArgs[] = {CGObjCGNU::EnforceType(Builder, ObjCSuper,
PtrToObjCSuperTy).getPointer(), cmd};
return CGF.EmitNounwindRuntimeCall(MsgLookupSuperFn, lookupArgs);
}
llvm::GlobalVariable *GetClassVar(StringRef Name, bool isWeak=false) {
std::string SymbolName = SymbolForClassRef(Name, isWeak);
auto *ClassSymbol = TheModule.getNamedGlobal(SymbolName);
if (ClassSymbol)
return ClassSymbol;
ClassSymbol = new llvm::GlobalVariable(TheModule,
IdTy, false, llvm::GlobalValue::ExternalLinkage,
nullptr, SymbolName);
// If this is a weak symbol, then we are creating a valid definition for
// the symbol, pointing to a weak definition of the real class pointer. If
// this is not a weak reference, then we are expecting another compilation
// unit to provide the real indirection symbol.
if (isWeak)
ClassSymbol->setInitializer(new llvm::GlobalVariable(TheModule,
Int8Ty, false, llvm::GlobalValue::ExternalWeakLinkage,
nullptr, SymbolForClass(Name)));
else {
if (CGM.getTriple().isOSBinFormatCOFF()) {
IdentifierInfo &II = CGM.getContext().Idents.get(Name);
TranslationUnitDecl *TUDecl = CGM.getContext().getTranslationUnitDecl();
DeclContext *DC = TranslationUnitDecl::castToDeclContext(TUDecl);
const ObjCInterfaceDecl *OID = nullptr;
for (const auto &Result : DC->lookup(&II))
if ((OID = dyn_cast<ObjCInterfaceDecl>(Result)))
break;
// The first Interface we find may be a @class,
// which should only be treated as the source of
// truth in the absence of a true declaration.
assert(OID && "Failed to find ObjCInterfaceDecl");
const ObjCInterfaceDecl *OIDDef = OID->getDefinition();
if (OIDDef != nullptr)
OID = OIDDef;
auto Storage = llvm::GlobalValue::DefaultStorageClass;
if (OID->hasAttr<DLLImportAttr>())
Storage = llvm::GlobalValue::DLLImportStorageClass;
else if (OID->hasAttr<DLLExportAttr>())
Storage = llvm::GlobalValue::DLLExportStorageClass;
cast<llvm::GlobalValue>(ClassSymbol)->setDLLStorageClass(Storage);
}
}
assert(ClassSymbol->getName() == SymbolName);
return ClassSymbol;
}
llvm::Value *GetClassNamed(CodeGenFunction &CGF,
const std::string &Name,
bool isWeak) override {
return CGF.Builder.CreateLoad(Address(GetClassVar(Name, isWeak),
CGM.getPointerAlign()));
}
int32_t FlagsForOwnership(Qualifiers::ObjCLifetime Ownership) {
// typedef enum {
// ownership_invalid = 0,
// ownership_strong = 1,
// ownership_weak = 2,
// ownership_unsafe = 3
// } ivar_ownership;
int Flag;
switch (Ownership) {
case Qualifiers::OCL_Strong:
Flag = 1;
break;
case Qualifiers::OCL_Weak:
Flag = 2;
break;
case Qualifiers::OCL_ExplicitNone:
Flag = 3;
break;
case Qualifiers::OCL_None:
case Qualifiers::OCL_Autoreleasing:
assert(Ownership != Qualifiers::OCL_Autoreleasing);
Flag = 0;
}
return Flag;
}
llvm::Constant *GenerateIvarList(ArrayRef<llvm::Constant *> IvarNames,
ArrayRef<llvm::Constant *> IvarTypes,
ArrayRef<llvm::Constant *> IvarOffsets,
ArrayRef<llvm::Constant *> IvarAlign,
ArrayRef<Qualifiers::ObjCLifetime> IvarOwnership) override {
llvm_unreachable("Method should not be called!");
}
llvm::Constant *GenerateEmptyProtocol(StringRef ProtocolName) override {
std::string Name = SymbolForProtocol(ProtocolName);
auto *GV = TheModule.getGlobalVariable(Name);
if (!GV) {
// Emit a placeholder symbol.
GV = new llvm::GlobalVariable(TheModule, ProtocolTy, false,
llvm::GlobalValue::ExternalLinkage, nullptr, Name);
GV->setAlignment(CGM.getPointerAlign().getAsAlign());
}
return llvm::ConstantExpr::getBitCast(GV, ProtocolPtrTy);
}
/// Existing protocol references.
llvm::StringMap<llvm::Constant*> ExistingProtocolRefs;
llvm::Value *GenerateProtocolRef(CodeGenFunction &CGF,
const ObjCProtocolDecl *PD) override {
auto Name = PD->getNameAsString();
auto *&Ref = ExistingProtocolRefs[Name];
if (!Ref) {
auto *&Protocol = ExistingProtocols[Name];
if (!Protocol)
Protocol = GenerateProtocolRef(PD);
std::string RefName = SymbolForProtocolRef(Name);
assert(!TheModule.getGlobalVariable(RefName));
// Emit a reference symbol.
auto GV = new llvm::GlobalVariable(TheModule, ProtocolPtrTy,
false, llvm::GlobalValue::LinkOnceODRLinkage,
llvm::ConstantExpr::getBitCast(Protocol, ProtocolPtrTy), RefName);
GV->setComdat(TheModule.getOrInsertComdat(RefName));
GV->setSection(sectionName<ProtocolReferenceSection>());
GV->setAlignment(CGM.getPointerAlign().getAsAlign());
Ref = GV;
}
EmittedProtocolRef = true;
return CGF.Builder.CreateAlignedLoad(ProtocolPtrTy, Ref,
CGM.getPointerAlign());
}
llvm::Constant *GenerateProtocolList(ArrayRef<llvm::Constant*> Protocols) {
llvm::ArrayType *ProtocolArrayTy = llvm::ArrayType::get(ProtocolPtrTy,
Protocols.size());
llvm::Constant * ProtocolArray = llvm::ConstantArray::get(ProtocolArrayTy,
Protocols);
ConstantInitBuilder builder(CGM);
auto ProtocolBuilder = builder.beginStruct();
ProtocolBuilder.addNullPointer(PtrTy);
ProtocolBuilder.addInt(SizeTy, Protocols.size());
ProtocolBuilder.add(ProtocolArray);
return ProtocolBuilder.finishAndCreateGlobal(".objc_protocol_list",
CGM.getPointerAlign(), false, llvm::GlobalValue::InternalLinkage);
}
void GenerateProtocol(const ObjCProtocolDecl *PD) override {
// Do nothing - we only emit referenced protocols.
}
llvm::Constant *GenerateProtocolRef(const ObjCProtocolDecl *PD) override {
std::string ProtocolName = PD->getNameAsString();
auto *&Protocol = ExistingProtocols[ProtocolName];
if (Protocol)
return Protocol;
EmittedProtocol = true;
auto SymName = SymbolForProtocol(ProtocolName);
auto *OldGV = TheModule.getGlobalVariable(SymName);
// Use the protocol definition, if there is one.
if (const ObjCProtocolDecl *Def = PD->getDefinition())
PD = Def;
else {
// If there is no definition, then create an external linkage symbol and
// hope that someone else fills it in for us (and fail to link if they
// don't).
assert(!OldGV);
Protocol = new llvm::GlobalVariable(TheModule, ProtocolTy,
/*isConstant*/false,
llvm::GlobalValue::ExternalLinkage, nullptr, SymName);
return Protocol;
}
SmallVector<llvm::Constant*, 16> Protocols;
auto RuntimeProtocols =
GetRuntimeProtocolList(PD->protocol_begin(), PD->protocol_end());
for (const auto *PI : RuntimeProtocols)
Protocols.push_back(
llvm::ConstantExpr::getBitCast(GenerateProtocolRef(PI),
ProtocolPtrTy));
llvm::Constant *ProtocolList = GenerateProtocolList(Protocols);
// Collect information about methods
llvm::Constant *InstanceMethodList, *OptionalInstanceMethodList;
llvm::Constant *ClassMethodList, *OptionalClassMethodList;
EmitProtocolMethodList(PD->instance_methods(), InstanceMethodList,
OptionalInstanceMethodList);
EmitProtocolMethodList(PD->class_methods(), ClassMethodList,
OptionalClassMethodList);
// The isa pointer must be set to a magic number so the runtime knows it's
// the correct layout.
ConstantInitBuilder builder(CGM);
auto ProtocolBuilder = builder.beginStruct();
ProtocolBuilder.add(llvm::ConstantExpr::getIntToPtr(
llvm::ConstantInt::get(Int32Ty, ProtocolVersion), IdTy));
ProtocolBuilder.add(MakeConstantString(ProtocolName));
ProtocolBuilder.add(ProtocolList);
ProtocolBuilder.add(InstanceMethodList);
ProtocolBuilder.add(ClassMethodList);
ProtocolBuilder.add(OptionalInstanceMethodList);
ProtocolBuilder.add(OptionalClassMethodList);
// Required instance properties
ProtocolBuilder.add(GeneratePropertyList(nullptr, PD, false, false));
// Optional instance properties
ProtocolBuilder.add(GeneratePropertyList(nullptr, PD, false, true));
// Required class properties
ProtocolBuilder.add(GeneratePropertyList(nullptr, PD, true, false));
// Optional class properties
ProtocolBuilder.add(GeneratePropertyList(nullptr, PD, true, true));
auto *GV = ProtocolBuilder.finishAndCreateGlobal(SymName,
CGM.getPointerAlign(), false, llvm::GlobalValue::ExternalLinkage);
GV->setSection(sectionName<ProtocolSection>());
GV->setComdat(TheModule.getOrInsertComdat(SymName));
if (OldGV) {
OldGV->replaceAllUsesWith(llvm::ConstantExpr::getBitCast(GV,
OldGV->getType()));
OldGV->removeFromParent();
GV->setName(SymName);
}
Protocol = GV;
return GV;
}
llvm::Constant *EnforceType(llvm::Constant *Val, llvm::Type *Ty) {
if (Val->getType() == Ty)
return Val;
return llvm::ConstantExpr::getBitCast(Val, Ty);
}
llvm::Value *GetTypedSelector(CodeGenFunction &CGF, Selector Sel,
const std::string &TypeEncoding) override {
return GetConstantSelector(Sel, TypeEncoding);
}
llvm::Constant *GetTypeString(llvm::StringRef TypeEncoding) {
if (TypeEncoding.empty())
return NULLPtr;
std::string MangledTypes = std::string(TypeEncoding);
std::replace(MangledTypes.begin(), MangledTypes.end(),
'@', '\1');
std::string TypesVarName = ".objc_sel_types_" + MangledTypes;
auto *TypesGlobal = TheModule.getGlobalVariable(TypesVarName);
if (!TypesGlobal) {
llvm::Constant *Init = llvm::ConstantDataArray::getString(VMContext,
TypeEncoding);
auto *GV = new llvm::GlobalVariable(TheModule, Init->getType(),
true, llvm::GlobalValue::LinkOnceODRLinkage, Init, TypesVarName);
GV->setComdat(TheModule.getOrInsertComdat(TypesVarName));
GV->setVisibility(llvm::GlobalValue::HiddenVisibility);
TypesGlobal = GV;
}
return llvm::ConstantExpr::getGetElementPtr(TypesGlobal->getValueType(),
TypesGlobal, Zeros);
}
llvm::Constant *GetConstantSelector(Selector Sel,
const std::string &TypeEncoding) override {
// @ is used as a special character in symbol names (used for symbol
// versioning), so mangle the name to not include it. Replace it with a
// character that is not a valid type encoding character (and, being
// non-printable, never will be!)
std::string MangledTypes = TypeEncoding;
std::replace(MangledTypes.begin(), MangledTypes.end(),
'@', '\1');
auto SelVarName = (StringRef(".objc_selector_") + Sel.getAsString() + "_" +
MangledTypes).str();
if (auto *GV = TheModule.getNamedGlobal(SelVarName))
return EnforceType(GV, SelectorTy);
ConstantInitBuilder builder(CGM);
auto SelBuilder = builder.beginStruct();
SelBuilder.add(ExportUniqueString(Sel.getAsString(), ".objc_sel_name_",
true));
SelBuilder.add(GetTypeString(TypeEncoding));
auto *GV = SelBuilder.finishAndCreateGlobal(SelVarName,
CGM.getPointerAlign(), false, llvm::GlobalValue::LinkOnceODRLinkage);
GV->setComdat(TheModule.getOrInsertComdat(SelVarName));
GV->setVisibility(llvm::GlobalValue::HiddenVisibility);
GV->setSection(sectionName<SelectorSection>());
auto *SelVal = EnforceType(GV, SelectorTy);
return SelVal;
}
llvm::StructType *emptyStruct = nullptr;
/// Return pointers to the start and end of a section. On ELF platforms, we
/// use the __start_ and __stop_ symbols that GNU-compatible linkers will set
/// to the start and end of section names, as long as those section names are
/// valid identifiers and the symbols are referenced but not defined. On
/// Windows, we use the fact that MSVC-compatible linkers will lexically sort
/// by subsections and place everything that we want to reference in a middle
/// subsection and then insert zero-sized symbols in subsections a and z.
std::pair<llvm::Constant*,llvm::Constant*>
GetSectionBounds(StringRef Section) {
if (CGM.getTriple().isOSBinFormatCOFF()) {
if (emptyStruct == nullptr) {
emptyStruct = llvm::StructType::create(VMContext, ".objc_section_sentinel");
emptyStruct->setBody({}, /*isPacked*/true);
}
auto ZeroInit = llvm::Constant::getNullValue(emptyStruct);
auto Sym = [&](StringRef Prefix, StringRef SecSuffix) {
auto *Sym = new llvm::GlobalVariable(TheModule, emptyStruct,
/*isConstant*/false,
llvm::GlobalValue::LinkOnceODRLinkage, ZeroInit, Prefix +
Section);
Sym->setVisibility(llvm::GlobalValue::HiddenVisibility);
Sym->setSection((Section + SecSuffix).str());
Sym->setComdat(TheModule.getOrInsertComdat((Prefix +
Section).str()));
Sym->setAlignment(CGM.getPointerAlign().getAsAlign());
return Sym;
};
return { Sym("__start_", "$a"), Sym("__stop", "$z") };
}
auto *Start = new llvm::GlobalVariable(TheModule, PtrTy,
/*isConstant*/false,
llvm::GlobalValue::ExternalLinkage, nullptr, StringRef("__start_") +
Section);
Start->setVisibility(llvm::GlobalValue::HiddenVisibility);
auto *Stop = new llvm::GlobalVariable(TheModule, PtrTy,
/*isConstant*/false,
llvm::GlobalValue::ExternalLinkage, nullptr, StringRef("__stop_") +
Section);
Stop->setVisibility(llvm::GlobalValue::HiddenVisibility);
return { Start, Stop };
}
CatchTypeInfo getCatchAllTypeInfo() override {
return CGM.getCXXABI().getCatchAllTypeInfo();
}
llvm::Function *ModuleInitFunction() override {
llvm::Function *LoadFunction = llvm::Function::Create(
llvm::FunctionType::get(llvm::Type::getVoidTy(VMContext), false),
llvm::GlobalValue::LinkOnceODRLinkage, ".objcv2_load_function",
&TheModule);
LoadFunction->setVisibility(llvm::GlobalValue::HiddenVisibility);
LoadFunction->setComdat(TheModule.getOrInsertComdat(".objcv2_load_function"));
llvm::BasicBlock *EntryBB =
llvm::BasicBlock::Create(VMContext, "entry", LoadFunction);
CGBuilderTy B(CGM, VMContext);
B.SetInsertPoint(EntryBB);
ConstantInitBuilder builder(CGM);
auto InitStructBuilder = builder.beginStruct();
InitStructBuilder.addInt(Int64Ty, 0);
auto &sectionVec = CGM.getTriple().isOSBinFormatCOFF() ? PECOFFSectionsBaseNames : SectionsBaseNames;
for (auto *s : sectionVec) {
auto bounds = GetSectionBounds(s);
InitStructBuilder.add(bounds.first);
InitStructBuilder.add(bounds.second);
}
auto *InitStruct = InitStructBuilder.finishAndCreateGlobal(".objc_init",
CGM.getPointerAlign(), false, llvm::GlobalValue::LinkOnceODRLinkage);
InitStruct->setVisibility(llvm::GlobalValue::HiddenVisibility);
InitStruct->setComdat(TheModule.getOrInsertComdat(".objc_init"));
CallRuntimeFunction(B, "__objc_load", {InitStruct});;
B.CreateRetVoid();
// Make sure that the optimisers don't delete this function.
CGM.addCompilerUsedGlobal(LoadFunction);
// FIXME: Currently ELF only!
// We have to do this by hand, rather than with @llvm.ctors, so that the
// linker can remove the duplicate invocations.
auto *InitVar = new llvm::GlobalVariable(TheModule, LoadFunction->getType(),
/*isConstant*/false, llvm::GlobalValue::LinkOnceAnyLinkage,
LoadFunction, ".objc_ctor");
// Check that this hasn't been renamed. This shouldn't happen, because
// this function should be called precisely once.
assert(InitVar->getName() == ".objc_ctor");
// In Windows, initialisers are sorted by the suffix. XCL is for library
// initialisers, which run before user initialisers. We are running
// Objective-C loads at the end of library load. This means +load methods
// will run before any other static constructors, but that static
// constructors can see a fully initialised Objective-C state.
if (CGM.getTriple().isOSBinFormatCOFF())
InitVar->setSection(".CRT$XCLz");
else
{
if (CGM.getCodeGenOpts().UseInitArray)
InitVar->setSection(".init_array");
else
InitVar->setSection(".ctors");
}
InitVar->setVisibility(llvm::GlobalValue::HiddenVisibility);
InitVar->setComdat(TheModule.getOrInsertComdat(".objc_ctor"));
CGM.addUsedGlobal(InitVar);
for (auto *C : Categories) {
auto *Cat = cast<llvm::GlobalVariable>(C->stripPointerCasts());
Cat->setSection(sectionName<CategorySection>());
CGM.addUsedGlobal(Cat);
}
auto createNullGlobal = [&](StringRef Name, ArrayRef<llvm::Constant*> Init,
StringRef Section) {
auto nullBuilder = builder.beginStruct();
for (auto *F : Init)
nullBuilder.add(F);
auto GV = nullBuilder.finishAndCreateGlobal(Name, CGM.getPointerAlign(),
false, llvm::GlobalValue::LinkOnceODRLinkage);
GV->setSection(Section);
GV->setComdat(TheModule.getOrInsertComdat(Name));
GV->setVisibility(llvm::GlobalValue::HiddenVisibility);
CGM.addUsedGlobal(GV);
return GV;
};
for (auto clsAlias : ClassAliases)
createNullGlobal(std::string(".objc_class_alias") +
clsAlias.second, { MakeConstantString(clsAlias.second),
GetClassVar(clsAlias.first) }, sectionName<ClassAliasSection>());
// On ELF platforms, add a null value for each special section so that we
// can always guarantee that the _start and _stop symbols will exist and be
// meaningful. This is not required on COFF platforms, where our start and
// stop symbols will create the section.
if (!CGM.getTriple().isOSBinFormatCOFF()) {
createNullGlobal(".objc_null_selector", {NULLPtr, NULLPtr},
sectionName<SelectorSection>());
if (Categories.empty())
createNullGlobal(".objc_null_category", {NULLPtr, NULLPtr,
NULLPtr, NULLPtr, NULLPtr, NULLPtr, NULLPtr},
sectionName<CategorySection>());
if (!EmittedClass) {
createNullGlobal(".objc_null_cls_init_ref", NULLPtr,
sectionName<ClassSection>());
createNullGlobal(".objc_null_class_ref", { NULLPtr, NULLPtr },
sectionName<ClassReferenceSection>());
}
if (!EmittedProtocol)
createNullGlobal(".objc_null_protocol", {NULLPtr, NULLPtr, NULLPtr,
NULLPtr, NULLPtr, NULLPtr, NULLPtr, NULLPtr, NULLPtr, NULLPtr,
NULLPtr}, sectionName<ProtocolSection>());
if (!EmittedProtocolRef)
createNullGlobal(".objc_null_protocol_ref", {NULLPtr},
sectionName<ProtocolReferenceSection>());
if (ClassAliases.empty())
createNullGlobal(".objc_null_class_alias", { NULLPtr, NULLPtr },
sectionName<ClassAliasSection>());
if (ConstantStrings.empty()) {
auto i32Zero = llvm::ConstantInt::get(Int32Ty, 0);
createNullGlobal(".objc_null_constant_string", { NULLPtr, i32Zero,
i32Zero, i32Zero, i32Zero, NULLPtr },
sectionName<ConstantStringSection>());
}
}
ConstantStrings.clear();
Categories.clear();
Classes.clear();
if (EarlyInitList.size() > 0) {
auto *Init = llvm::Function::Create(llvm::FunctionType::get(CGM.VoidTy,
{}), llvm::GlobalValue::InternalLinkage, ".objc_early_init",
&CGM.getModule());
llvm::IRBuilder<> b(llvm::BasicBlock::Create(CGM.getLLVMContext(), "entry",
Init));
for (const auto &lateInit : EarlyInitList) {
auto *global = TheModule.getGlobalVariable(lateInit.first);
if (global) {
b.CreateAlignedStore(
global,
b.CreateStructGEP(lateInit.second.first, lateInit.second.second),
CGM.getPointerAlign().getAsAlign());
}
}
b.CreateRetVoid();
// We can't use the normal LLVM global initialisation array, because we
// need to specify that this runs early in library initialisation.
auto *InitVar = new llvm::GlobalVariable(CGM.getModule(), Init->getType(),
/*isConstant*/true, llvm::GlobalValue::InternalLinkage,
Init, ".objc_early_init_ptr");
InitVar->setSection(".CRT$XCLb");
CGM.addUsedGlobal(InitVar);
}
return nullptr;
}
/// In the v2 ABI, ivar offset variables use the type encoding in their name
/// to trigger linker failures if the types don't match.
std::string GetIVarOffsetVariableName(const ObjCInterfaceDecl *ID,
const ObjCIvarDecl *Ivar) override {
std::string TypeEncoding;
CGM.getContext().getObjCEncodingForType(Ivar->getType(), TypeEncoding);
// Prevent the @ from being interpreted as a symbol version.
std::replace(TypeEncoding.begin(), TypeEncoding.end(),
'@', '\1');
const std::string Name = "__objc_ivar_offset_" + ID->getNameAsString()
+ '.' + Ivar->getNameAsString() + '.' + TypeEncoding;
return Name;
}
llvm::Value *EmitIvarOffset(CodeGenFunction &CGF,
const ObjCInterfaceDecl *Interface,
const ObjCIvarDecl *Ivar) override {
const std::string Name = GetIVarOffsetVariableName(Ivar->getContainingInterface(), Ivar);
llvm::GlobalVariable *IvarOffsetPointer = TheModule.getNamedGlobal(Name);
if (!IvarOffsetPointer)
IvarOffsetPointer = new llvm::GlobalVariable(TheModule, IntTy, false,
llvm::GlobalValue::ExternalLinkage, nullptr, Name);
CharUnits Align = CGM.getIntAlign();
llvm::Value *Offset =
CGF.Builder.CreateAlignedLoad(IntTy, IvarOffsetPointer, Align);
if (Offset->getType() != PtrDiffTy)
Offset = CGF.Builder.CreateZExtOrBitCast(Offset, PtrDiffTy);
return Offset;
}
void GenerateClass(const ObjCImplementationDecl *OID) override {
ASTContext &Context = CGM.getContext();
bool IsCOFF = CGM.getTriple().isOSBinFormatCOFF();
// Get the class name
ObjCInterfaceDecl *classDecl =
const_cast<ObjCInterfaceDecl *>(OID->getClassInterface());
std::string className = classDecl->getNameAsString();
auto *classNameConstant = MakeConstantString(className);
ConstantInitBuilder builder(CGM);
auto metaclassFields = builder.beginStruct();
// struct objc_class *isa;
metaclassFields.addNullPointer(PtrTy);
// struct objc_class *super_class;
metaclassFields.addNullPointer(PtrTy);
// const char *name;
metaclassFields.add(classNameConstant);
// long version;
metaclassFields.addInt(LongTy, 0);
// unsigned long info;
// objc_class_flag_meta
metaclassFields.addInt(LongTy, 1);
// long instance_size;
// Setting this to zero is consistent with the older ABI, but it might be
// more sensible to set this to sizeof(struct objc_class)
metaclassFields.addInt(LongTy, 0);
// struct objc_ivar_list *ivars;
metaclassFields.addNullPointer(PtrTy);
// struct objc_method_list *methods
// FIXME: Almost identical code is copied and pasted below for the
// class, but refactoring it cleanly requires C++14 generic lambdas.
if (OID->classmeth_begin() == OID->classmeth_end())
metaclassFields.addNullPointer(PtrTy);
else {
SmallVector<ObjCMethodDecl*, 16> ClassMethods;
ClassMethods.insert(ClassMethods.begin(), OID->classmeth_begin(),
OID->classmeth_end());
metaclassFields.addBitCast(
GenerateMethodList(className, "", ClassMethods, true),
PtrTy);
}
// void *dtable;
metaclassFields.addNullPointer(PtrTy);
// IMP cxx_construct;
metaclassFields.addNullPointer(PtrTy);
// IMP cxx_destruct;
metaclassFields.addNullPointer(PtrTy);
// struct objc_class *subclass_list
metaclassFields.addNullPointer(PtrTy);
// struct objc_class *sibling_class
metaclassFields.addNullPointer(PtrTy);
// struct objc_protocol_list *protocols;
metaclassFields.addNullPointer(PtrTy);
// struct reference_list *extra_data;
metaclassFields.addNullPointer(PtrTy);
// long abi_version;
metaclassFields.addInt(LongTy, 0);
// struct objc_property_list *properties
metaclassFields.add(GeneratePropertyList(OID, classDecl, /*isClassProperty*/true));
auto *metaclass = metaclassFields.finishAndCreateGlobal(
ManglePublicSymbol("OBJC_METACLASS_") + className,
CGM.getPointerAlign());
auto classFields = builder.beginStruct();
// struct objc_class *isa;
classFields.add(metaclass);
// struct objc_class *super_class;
// Get the superclass name.
const ObjCInterfaceDecl * SuperClassDecl =
OID->getClassInterface()->getSuperClass();
llvm::Constant *SuperClass = nullptr;
if (SuperClassDecl) {
auto SuperClassName = SymbolForClass(SuperClassDecl->getNameAsString());
SuperClass = TheModule.getNamedGlobal(SuperClassName);
if (!SuperClass)
{
SuperClass = new llvm::GlobalVariable(TheModule, PtrTy, false,
llvm::GlobalValue::ExternalLinkage, nullptr, SuperClassName);
if (IsCOFF) {
auto Storage = llvm::GlobalValue::DefaultStorageClass;
if (SuperClassDecl->hasAttr<DLLImportAttr>())
Storage = llvm::GlobalValue::DLLImportStorageClass;
else if (SuperClassDecl->hasAttr<DLLExportAttr>())
Storage = llvm::GlobalValue::DLLExportStorageClass;
cast<llvm::GlobalValue>(SuperClass)->setDLLStorageClass(Storage);
}
}
if (!IsCOFF)
classFields.add(llvm::ConstantExpr::getBitCast(SuperClass, PtrTy));
else
classFields.addNullPointer(PtrTy);
} else
classFields.addNullPointer(PtrTy);
// const char *name;
classFields.add(classNameConstant);
// long version;
classFields.addInt(LongTy, 0);
// unsigned long info;
// !objc_class_flag_meta
classFields.addInt(LongTy, 0);
// long instance_size;
int superInstanceSize = !SuperClassDecl ? 0 :
Context.getASTObjCInterfaceLayout(SuperClassDecl).getSize().getQuantity();
// Instance size is negative for classes that have not yet had their ivar
// layout calculated.
classFields.addInt(LongTy,
0 - (Context.getASTObjCImplementationLayout(OID).getSize().getQuantity() -
superInstanceSize));
if (classDecl->all_declared_ivar_begin() == nullptr)
classFields.addNullPointer(PtrTy);
else {
int ivar_count = 0;
for (const ObjCIvarDecl *IVD = classDecl->all_declared_ivar_begin(); IVD;
IVD = IVD->getNextIvar()) ivar_count++;
llvm::DataLayout td(&TheModule);
// struct objc_ivar_list *ivars;
ConstantInitBuilder b(CGM);
auto ivarListBuilder = b.beginStruct();
// int count;
ivarListBuilder.addInt(IntTy, ivar_count);
// size_t size;
llvm::StructType *ObjCIvarTy = llvm::StructType::get(
PtrToInt8Ty,
PtrToInt8Ty,
PtrToInt8Ty,
Int32Ty,
Int32Ty);
ivarListBuilder.addInt(SizeTy, td.getTypeSizeInBits(ObjCIvarTy) /
CGM.getContext().getCharWidth());
// struct objc_ivar ivars[]
auto ivarArrayBuilder = ivarListBuilder.beginArray();
for (const ObjCIvarDecl *IVD = classDecl->all_declared_ivar_begin(); IVD;
IVD = IVD->getNextIvar()) {
auto ivarTy = IVD->getType();
auto ivarBuilder = ivarArrayBuilder.beginStruct();
// const char *name;
ivarBuilder.add(MakeConstantString(IVD->getNameAsString()));
// const char *type;
std::string TypeStr;
//Context.getObjCEncodingForType(ivarTy, TypeStr, IVD, true);
Context.getObjCEncodingForMethodParameter(Decl::OBJC_TQ_None, ivarTy, TypeStr, true);
ivarBuilder.add(MakeConstantString(TypeStr));
// int *offset;
uint64_t BaseOffset = ComputeIvarBaseOffset(CGM, OID, IVD);
uint64_t Offset = BaseOffset - superInstanceSize;
llvm::Constant *OffsetValue = llvm::ConstantInt::get(IntTy, Offset);
std::string OffsetName = GetIVarOffsetVariableName(classDecl, IVD);
llvm::GlobalVariable *OffsetVar = TheModule.getGlobalVariable(OffsetName);
if (OffsetVar)
OffsetVar->setInitializer(OffsetValue);
else
OffsetVar = new llvm::GlobalVariable(TheModule, IntTy,
false, llvm::GlobalValue::ExternalLinkage,
OffsetValue, OffsetName);
auto ivarVisibility =
(IVD->getAccessControl() == ObjCIvarDecl::Private ||
IVD->getAccessControl() == ObjCIvarDecl::Package ||
classDecl->getVisibility() == HiddenVisibility) ?
llvm::GlobalValue::HiddenVisibility :
llvm::GlobalValue::DefaultVisibility;
OffsetVar->setVisibility(ivarVisibility);
ivarBuilder.add(OffsetVar);
// Ivar size
ivarBuilder.addInt(Int32Ty,
CGM.getContext().getTypeSizeInChars(ivarTy).getQuantity());
// Alignment will be stored as a base-2 log of the alignment.
unsigned align =
llvm::Log2_32(Context.getTypeAlignInChars(ivarTy).getQuantity());
// Objects that require more than 2^64-byte alignment should be impossible!
assert(align < 64);
// uint32_t flags;
// Bits 0-1 are ownership.
// Bit 2 indicates an extended type encoding
// Bits 3-8 contain log2(aligment)
ivarBuilder.addInt(Int32Ty,
(align << 3) | (1<<2) |
FlagsForOwnership(ivarTy.getQualifiers().getObjCLifetime()));
ivarBuilder.finishAndAddTo(ivarArrayBuilder);
}
ivarArrayBuilder.finishAndAddTo(ivarListBuilder);
auto ivarList = ivarListBuilder.finishAndCreateGlobal(".objc_ivar_list",
CGM.getPointerAlign(), /*constant*/ false,
llvm::GlobalValue::PrivateLinkage);
classFields.add(ivarList);
}
// struct objc_method_list *methods
SmallVector<const ObjCMethodDecl*, 16> InstanceMethods;
InstanceMethods.insert(InstanceMethods.begin(), OID->instmeth_begin(),
OID->instmeth_end());
for (auto *propImpl : OID->property_impls())
if (propImpl->getPropertyImplementation() ==
ObjCPropertyImplDecl::Synthesize) {
auto addIfExists = [&](const ObjCMethodDecl *OMD) {
if (OMD && OMD->hasBody())
InstanceMethods.push_back(OMD);
};
addIfExists(propImpl->getGetterMethodDecl());
addIfExists(propImpl->getSetterMethodDecl());
}
if (InstanceMethods.size() == 0)
classFields.addNullPointer(PtrTy);
else
classFields.addBitCast(
GenerateMethodList(className, "", InstanceMethods, false),
PtrTy);
// void *dtable;
classFields.addNullPointer(PtrTy);
// IMP cxx_construct;
classFields.addNullPointer(PtrTy);
// IMP cxx_destruct;
classFields.addNullPointer(PtrTy);
// struct objc_class *subclass_list
classFields.addNullPointer(PtrTy);
// struct objc_class *sibling_class
classFields.addNullPointer(PtrTy);
// struct objc_protocol_list *protocols;
auto RuntimeProtocols = GetRuntimeProtocolList(classDecl->protocol_begin(),
classDecl->protocol_end());
SmallVector<llvm::Constant *, 16> Protocols;
for (const auto *I : RuntimeProtocols)
Protocols.push_back(
llvm::ConstantExpr::getBitCast(GenerateProtocolRef(I),
ProtocolPtrTy));
if (Protocols.empty())
classFields.addNullPointer(PtrTy);
else
classFields.add(GenerateProtocolList(Protocols));
// struct reference_list *extra_data;
classFields.addNullPointer(PtrTy);
// long abi_version;
classFields.addInt(LongTy, 0);
// struct objc_property_list *properties
classFields.add(GeneratePropertyList(OID, classDecl));
auto *classStruct =
classFields.finishAndCreateGlobal(SymbolForClass(className),
CGM.getPointerAlign(), false, llvm::GlobalValue::ExternalLinkage);
auto *classRefSymbol = GetClassVar(className);
classRefSymbol->setSection(sectionName<ClassReferenceSection>());
classRefSymbol->setInitializer(llvm::ConstantExpr::getBitCast(classStruct, IdTy));
if (IsCOFF) {
// we can't import a class struct.
if (OID->getClassInterface()->hasAttr<DLLExportAttr>()) {
cast<llvm::GlobalValue>(classStruct)->setDLLStorageClass(llvm::GlobalValue::DLLExportStorageClass);
cast<llvm::GlobalValue>(classRefSymbol)->setDLLStorageClass(llvm::GlobalValue::DLLExportStorageClass);
}
if (SuperClass) {
std::pair<llvm::Constant*, int> v{classStruct, 1};
EarlyInitList.emplace_back(std::string(SuperClass->getName()),
std::move(v));
}
}
// Resolve the class aliases, if they exist.
// FIXME: Class pointer aliases shouldn't exist!
if (ClassPtrAlias) {
ClassPtrAlias->replaceAllUsesWith(
llvm::ConstantExpr::getBitCast(classStruct, IdTy));
ClassPtrAlias->eraseFromParent();
ClassPtrAlias = nullptr;
}
if (auto Placeholder =
TheModule.getNamedGlobal(SymbolForClass(className)))
if (Placeholder != classStruct) {
Placeholder->replaceAllUsesWith(
llvm::ConstantExpr::getBitCast(classStruct, Placeholder->getType()));
Placeholder->eraseFromParent();
classStruct->setName(SymbolForClass(className));
}
if (MetaClassPtrAlias) {
MetaClassPtrAlias->replaceAllUsesWith(
llvm::ConstantExpr::getBitCast(metaclass, IdTy));
MetaClassPtrAlias->eraseFromParent();
MetaClassPtrAlias = nullptr;
}
assert(classStruct->getName() == SymbolForClass(className));
auto classInitRef = new llvm::GlobalVariable(TheModule,
classStruct->getType(), false, llvm::GlobalValue::ExternalLinkage,
classStruct, ManglePublicSymbol("OBJC_INIT_CLASS_") + className);
classInitRef->setSection(sectionName<ClassSection>());
CGM.addUsedGlobal(classInitRef);
EmittedClass = true;
}
public:
CGObjCGNUstep2(CodeGenModule &Mod) : CGObjCGNUstep(Mod, 10, 4, 2) {
MsgLookupSuperFn.init(&CGM, "objc_msg_lookup_super", IMPTy,
PtrToObjCSuperTy, SelectorTy);
// struct objc_property
// {
// const char *name;
// const char *attributes;
// const char *type;
// SEL getter;
// SEL setter;
// }
PropertyMetadataTy =
llvm::StructType::get(CGM.getLLVMContext(),
{ PtrToInt8Ty, PtrToInt8Ty, PtrToInt8Ty, PtrToInt8Ty, PtrToInt8Ty });
}
};
const char *const CGObjCGNUstep2::SectionsBaseNames[8] =
{
"__objc_selectors",
"__objc_classes",
"__objc_class_refs",
"__objc_cats",
"__objc_protocols",
"__objc_protocol_refs",
"__objc_class_aliases",
"__objc_constant_string"
};
const char *const CGObjCGNUstep2::PECOFFSectionsBaseNames[8] =
{
".objcrt$SEL",
".objcrt$CLS",
".objcrt$CLR",
".objcrt$CAT",
".objcrt$PCL",
".objcrt$PCR",
".objcrt$CAL",
".objcrt$STR"
};
/// Support for the ObjFW runtime.
class CGObjCObjFW: public CGObjCGNU {
protected:
/// The GCC ABI message lookup function. Returns an IMP pointing to the
/// method implementation for this message.
LazyRuntimeFunction MsgLookupFn;
/// stret lookup function. While this does not seem to make sense at the
/// first look, this is required to call the correct forwarding function.
LazyRuntimeFunction MsgLookupFnSRet;
/// The GCC ABI superclass message lookup function. Takes a pointer to a
/// structure describing the receiver and the class, and a selector as
/// arguments. Returns the IMP for the corresponding method.
LazyRuntimeFunction MsgLookupSuperFn, MsgLookupSuperFnSRet;
llvm::Value *LookupIMP(CodeGenFunction &CGF, llvm::Value *&Receiver,
llvm::Value *cmd, llvm::MDNode *node,
MessageSendInfo &MSI) override {
CGBuilderTy &Builder = CGF.Builder;
llvm::Value *args[] = {
EnforceType(Builder, Receiver, IdTy),
EnforceType(Builder, cmd, SelectorTy) };
llvm::CallBase *imp;
if (CGM.ReturnTypeUsesSRet(MSI.CallInfo))
imp = CGF.EmitRuntimeCallOrInvoke(MsgLookupFnSRet, args);
else
imp = CGF.EmitRuntimeCallOrInvoke(MsgLookupFn, args);
imp->setMetadata(msgSendMDKind, node);
return imp;
}
llvm::Value *LookupIMPSuper(CodeGenFunction &CGF, Address ObjCSuper,
llvm::Value *cmd, MessageSendInfo &MSI) override {
CGBuilderTy &Builder = CGF.Builder;
llvm::Value *lookupArgs[] = {
EnforceType(Builder, ObjCSuper.getPointer(), PtrToObjCSuperTy), cmd,
};
if (CGM.ReturnTypeUsesSRet(MSI.CallInfo))
return CGF.EmitNounwindRuntimeCall(MsgLookupSuperFnSRet, lookupArgs);
else
return CGF.EmitNounwindRuntimeCall(MsgLookupSuperFn, lookupArgs);
}
llvm::Value *GetClassNamed(CodeGenFunction &CGF, const std::string &Name,
bool isWeak) override {
if (isWeak)
return CGObjCGNU::GetClassNamed(CGF, Name, isWeak);
EmitClassRef(Name);
std::string SymbolName = "_OBJC_CLASS_" + Name;
llvm::GlobalVariable *ClassSymbol = TheModule.getGlobalVariable(SymbolName);
if (!ClassSymbol)
ClassSymbol = new llvm::GlobalVariable(TheModule, LongTy, false,
llvm::GlobalValue::ExternalLinkage,
nullptr, SymbolName);
return ClassSymbol;
}
public:
CGObjCObjFW(CodeGenModule &Mod): CGObjCGNU(Mod, 9, 3) {
// IMP objc_msg_lookup(id, SEL);
MsgLookupFn.init(&CGM, "objc_msg_lookup", IMPTy, IdTy, SelectorTy);
MsgLookupFnSRet.init(&CGM, "objc_msg_lookup_stret", IMPTy, IdTy,
SelectorTy);
// IMP objc_msg_lookup_super(struct objc_super*, SEL);
MsgLookupSuperFn.init(&CGM, "objc_msg_lookup_super", IMPTy,
PtrToObjCSuperTy, SelectorTy);
MsgLookupSuperFnSRet.init(&CGM, "objc_msg_lookup_super_stret", IMPTy,
PtrToObjCSuperTy, SelectorTy);
}
};
} // end anonymous namespace
/// Emits a reference to a dummy variable which is emitted with each class.
/// This ensures that a linker error will be generated when trying to link
/// together modules where a referenced class is not defined.
void CGObjCGNU::EmitClassRef(const std::string &className) {
std::string symbolRef = "__objc_class_ref_" + className;
// Don't emit two copies of the same symbol
if (TheModule.getGlobalVariable(symbolRef))
return;
std::string symbolName = "__objc_class_name_" + className;
llvm::GlobalVariable *ClassSymbol = TheModule.getGlobalVariable(symbolName);
if (!ClassSymbol) {
ClassSymbol = new llvm::GlobalVariable(TheModule, LongTy, false,
llvm::GlobalValue::ExternalLinkage,
nullptr, symbolName);
}
new llvm::GlobalVariable(TheModule, ClassSymbol->getType(), true,
llvm::GlobalValue::WeakAnyLinkage, ClassSymbol, symbolRef);
}
CGObjCGNU::CGObjCGNU(CodeGenModule &cgm, unsigned runtimeABIVersion,
unsigned protocolClassVersion, unsigned classABI)
: CGObjCRuntime(cgm), TheModule(CGM.getModule()),
VMContext(cgm.getLLVMContext()), ClassPtrAlias(nullptr),
MetaClassPtrAlias(nullptr), RuntimeVersion(runtimeABIVersion),
ProtocolVersion(protocolClassVersion), ClassABIVersion(classABI) {
msgSendMDKind = VMContext.getMDKindID("GNUObjCMessageSend");
usesSEHExceptions =
cgm.getContext().getTargetInfo().getTriple().isWindowsMSVCEnvironment();
CodeGenTypes &Types = CGM.getTypes();
IntTy = cast<llvm::IntegerType>(
Types.ConvertType(CGM.getContext().IntTy));
LongTy = cast<llvm::IntegerType>(
Types.ConvertType(CGM.getContext().LongTy));
SizeTy = cast<llvm::IntegerType>(
Types.ConvertType(CGM.getContext().getSizeType()));
PtrDiffTy = cast<llvm::IntegerType>(
Types.ConvertType(CGM.getContext().getPointerDiffType()));
BoolTy = CGM.getTypes().ConvertType(CGM.getContext().BoolTy);
Int8Ty = llvm::Type::getInt8Ty(VMContext);
// C string type. Used in lots of places.
PtrToInt8Ty = llvm::PointerType::getUnqual(Int8Ty);
ProtocolPtrTy = llvm::PointerType::getUnqual(
Types.ConvertType(CGM.getContext().getObjCProtoType()));
Zeros[0] = llvm::ConstantInt::get(LongTy, 0);
Zeros[1] = Zeros[0];
NULLPtr = llvm::ConstantPointerNull::get(PtrToInt8Ty);
// Get the selector Type.
QualType selTy = CGM.getContext().getObjCSelType();
if (QualType() == selTy) {
SelectorTy = PtrToInt8Ty;
} else {
SelectorTy = cast<llvm::PointerType>(CGM.getTypes().ConvertType(selTy));
}
PtrToIntTy = llvm::PointerType::getUnqual(IntTy);
PtrTy = PtrToInt8Ty;
Int32Ty = llvm::Type::getInt32Ty(VMContext);
Int64Ty = llvm::Type::getInt64Ty(VMContext);
IntPtrTy =
CGM.getDataLayout().getPointerSizeInBits() == 32 ? Int32Ty : Int64Ty;
// Object type
QualType UnqualIdTy = CGM.getContext().getObjCIdType();
ASTIdTy = CanQualType();
if (UnqualIdTy != QualType()) {
ASTIdTy = CGM.getContext().getCanonicalType(UnqualIdTy);
IdTy = cast<llvm::PointerType>(CGM.getTypes().ConvertType(ASTIdTy));
} else {
IdTy = PtrToInt8Ty;
}
PtrToIdTy = llvm::PointerType::getUnqual(IdTy);
ProtocolTy = llvm::StructType::get(IdTy,
PtrToInt8Ty, // name
PtrToInt8Ty, // protocols
PtrToInt8Ty, // instance methods
PtrToInt8Ty, // class methods
PtrToInt8Ty, // optional instance methods
PtrToInt8Ty, // optional class methods
PtrToInt8Ty, // properties
PtrToInt8Ty);// optional properties
// struct objc_property_gsv1
// {
// const char *name;
// char attributes;
// char attributes2;
// char unused1;
// char unused2;
// const char *getter_name;
// const char *getter_types;
// const char *setter_name;
// const char *setter_types;
// }
PropertyMetadataTy = llvm::StructType::get(CGM.getLLVMContext(), {
PtrToInt8Ty, Int8Ty, Int8Ty, Int8Ty, Int8Ty, PtrToInt8Ty, PtrToInt8Ty,
PtrToInt8Ty, PtrToInt8Ty });
ObjCSuperTy = llvm::StructType::get(IdTy, IdTy);
PtrToObjCSuperTy = llvm::PointerType::getUnqual(ObjCSuperTy);
llvm::Type *VoidTy = llvm::Type::getVoidTy(VMContext);
// void objc_exception_throw(id);
ExceptionThrowFn.init(&CGM, "objc_exception_throw", VoidTy, IdTy);
ExceptionReThrowFn.init(&CGM, "objc_exception_throw", VoidTy, IdTy);
// int objc_sync_enter(id);
SyncEnterFn.init(&CGM, "objc_sync_enter", IntTy, IdTy);
// int objc_sync_exit(id);
SyncExitFn.init(&CGM, "objc_sync_exit", IntTy, IdTy);
// void objc_enumerationMutation (id)
EnumerationMutationFn.init(&CGM, "objc_enumerationMutation", VoidTy, IdTy);
// id objc_getProperty(id, SEL, ptrdiff_t, BOOL)
GetPropertyFn.init(&CGM, "objc_getProperty", IdTy, IdTy, SelectorTy,
PtrDiffTy, BoolTy);
// void objc_setProperty(id, SEL, ptrdiff_t, id, BOOL, BOOL)
SetPropertyFn.init(&CGM, "objc_setProperty", VoidTy, IdTy, SelectorTy,
PtrDiffTy, IdTy, BoolTy, BoolTy);
// void objc_setPropertyStruct(void*, void*, ptrdiff_t, BOOL, BOOL)
GetStructPropertyFn.init(&CGM, "objc_getPropertyStruct", VoidTy, PtrTy, PtrTy,
PtrDiffTy, BoolTy, BoolTy);
// void objc_setPropertyStruct(void*, void*, ptrdiff_t, BOOL, BOOL)
SetStructPropertyFn.init(&CGM, "objc_setPropertyStruct", VoidTy, PtrTy, PtrTy,
PtrDiffTy, BoolTy, BoolTy);
// IMP type
llvm::Type *IMPArgs[] = { IdTy, SelectorTy };
IMPTy = llvm::PointerType::getUnqual(llvm::FunctionType::get(IdTy, IMPArgs,
true));
const LangOptions &Opts = CGM.getLangOpts();
if ((Opts.getGC() != LangOptions::NonGC) || Opts.ObjCAutoRefCount)
RuntimeVersion = 10;
// Don't bother initialising the GC stuff unless we're compiling in GC mode
if (Opts.getGC() != LangOptions::NonGC) {
// This is a bit of an hack. We should sort this out by having a proper
// CGObjCGNUstep subclass for GC, but we may want to really support the old
// ABI and GC added in ObjectiveC2.framework, so we fudge it a bit for now
// Get selectors needed in GC mode
RetainSel = GetNullarySelector("retain", CGM.getContext());
ReleaseSel = GetNullarySelector("release", CGM.getContext());
AutoreleaseSel = GetNullarySelector("autorelease", CGM.getContext());
// Get functions needed in GC mode
// id objc_assign_ivar(id, id, ptrdiff_t);
IvarAssignFn.init(&CGM, "objc_assign_ivar", IdTy, IdTy, IdTy, PtrDiffTy);
// id objc_assign_strongCast (id, id*)
StrongCastAssignFn.init(&CGM, "objc_assign_strongCast", IdTy, IdTy,
PtrToIdTy);
// id objc_assign_global(id, id*);
GlobalAssignFn.init(&CGM, "objc_assign_global", IdTy, IdTy, PtrToIdTy);
// id objc_assign_weak(id, id*);
WeakAssignFn.init(&CGM, "objc_assign_weak", IdTy, IdTy, PtrToIdTy);
// id objc_read_weak(id*);
WeakReadFn.init(&CGM, "objc_read_weak", IdTy, PtrToIdTy);
// void *objc_memmove_collectable(void*, void *, size_t);
MemMoveFn.init(&CGM, "objc_memmove_collectable", PtrTy, PtrTy, PtrTy,
SizeTy);
}
}
llvm::Value *CGObjCGNU::GetClassNamed(CodeGenFunction &CGF,
const std::string &Name, bool isWeak) {
llvm::Constant *ClassName = MakeConstantString(Name);
// With the incompatible ABI, this will need to be replaced with a direct
// reference to the class symbol. For the compatible nonfragile ABI we are
// still performing this lookup at run time but emitting the symbol for the
// class externally so that we can make the switch later.
//
// Libobjc2 contains an LLVM pass that replaces calls to objc_lookup_class
// with memoized versions or with static references if it's safe to do so.
if (!isWeak)
EmitClassRef(Name);
llvm::FunctionCallee ClassLookupFn = CGM.CreateRuntimeFunction(
llvm::FunctionType::get(IdTy, PtrToInt8Ty, true), "objc_lookup_class");
return CGF.EmitNounwindRuntimeCall(ClassLookupFn, ClassName);
}
// This has to perform the lookup every time, since posing and related
// techniques can modify the name -> class mapping.
llvm::Value *CGObjCGNU::GetClass(CodeGenFunction &CGF,
const ObjCInterfaceDecl *OID) {
auto *Value =
GetClassNamed(CGF, OID->getNameAsString(), OID->isWeakImported());
if (auto *ClassSymbol = dyn_cast<llvm::GlobalVariable>(Value))
CGM.setGVProperties(ClassSymbol, OID);
return Value;
}
llvm::Value *CGObjCGNU::EmitNSAutoreleasePoolClassRef(CodeGenFunction &CGF) {
auto *Value = GetClassNamed(CGF, "NSAutoreleasePool", false);
if (CGM.getTriple().isOSBinFormatCOFF()) {
if (auto *ClassSymbol = dyn_cast<llvm::GlobalVariable>(Value)) {
IdentifierInfo &II = CGF.CGM.getContext().Idents.get("NSAutoreleasePool");
TranslationUnitDecl *TUDecl = CGM.getContext().getTranslationUnitDecl();
DeclContext *DC = TranslationUnitDecl::castToDeclContext(TUDecl);
const VarDecl *VD = nullptr;
for (const auto &Result : DC->lookup(&II))
if ((VD = dyn_cast<VarDecl>(Result)))
break;
CGM.setGVProperties(ClassSymbol, VD);
}
}
return Value;
}
llvm::Value *CGObjCGNU::GetTypedSelector(CodeGenFunction &CGF, Selector Sel,
const std::string &TypeEncoding) {
SmallVectorImpl<TypedSelector> &Types = SelectorTable[Sel];
llvm::GlobalAlias *SelValue = nullptr;
for (SmallVectorImpl<TypedSelector>::iterator i = Types.begin(),
e = Types.end() ; i!=e ; i++) {
if (i->first == TypeEncoding) {
SelValue = i->second;
break;
}
}
if (!SelValue) {
SelValue = llvm::GlobalAlias::create(
SelectorTy->getElementType(), 0, llvm::GlobalValue::PrivateLinkage,
".objc_selector_" + Sel.getAsString(), &TheModule);
Types.emplace_back(TypeEncoding, SelValue);
}
return SelValue;
}
Address CGObjCGNU::GetAddrOfSelector(CodeGenFunction &CGF, Selector Sel) {
llvm::Value *SelValue = GetSelector(CGF, Sel);
// Store it to a temporary. Does this satisfy the semantics of
// GetAddrOfSelector? Hopefully.
Address tmp = CGF.CreateTempAlloca(SelValue->getType(),
CGF.getPointerAlign());
CGF.Builder.CreateStore(SelValue, tmp);
return tmp;
}
llvm::Value *CGObjCGNU::GetSelector(CodeGenFunction &CGF, Selector Sel) {
return GetTypedSelector(CGF, Sel, std::string());
}
llvm::Value *CGObjCGNU::GetSelector(CodeGenFunction &CGF,
const ObjCMethodDecl *Method) {
std::string SelTypes = CGM.getContext().getObjCEncodingForMethodDecl(Method);
return GetTypedSelector(CGF, Method->getSelector(), SelTypes);
}
llvm::Constant