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//===------- CGObjCGNU.cpp - Emit LLVM Code from ASTs for a Module --------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// 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 "CGObjCRuntime.h"
#include "CGCleanup.h"
#include "CodeGenFunction.h"
#include "CodeGenModule.h"
#include "CGCXXABI.h"
#include "clang/CodeGen/ConstantInitBuilder.h"
#include "clang/AST/ASTContext.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 "llvm/ADT/SmallVector.h"
#include "llvm/ADT/StringMap.h"
#include "llvm/IR/CallSite.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 {
std::string SymbolNameForMethod( StringRef ClassName,
StringRef CategoryName, const Selector MethodName,
bool isClassMethod) {
std::string MethodNameColonStripped = MethodName.getAsString();
std::replace(MethodNameColonStripped.begin(), MethodNameColonStripped.end(),
':', '_');
return (Twine(isClassMethod ? "_c_" : "_i_") + ClassName + "_" +
CategoryName + "_" + MethodNameColonStripped).str();
}
/// 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::Constant *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::Constant *() {
if (!Function) {
if (!FunctionName)
return nullptr;
Function = CGM->CreateRuntimeFunction(FTy, FunctionName);
}
return Function;
}
operator llvm::Function *() {
return cast<llvm::Function>((llvm::Constant *)*this);
}
};
/// 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 SymbolForProtocol(StringRef Name) {
return (StringRef("._OBJC_PROTOCOL_") + Name).str();
}
std::string SymbolForProtocolRef(StringRef Name) {
return (StringRef("._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(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 & ObjCPropertyDecl::OBJC_PR_readonly) {
attrs &= ~ObjCPropertyDecl::OBJC_PR_copy;
attrs &= ~ObjCPropertyDecl::OBJC_PR_retain;
attrs &= ~ObjCPropertyDecl::OBJC_PR_weak;
attrs &= ~ObjCPropertyDecl::OBJC_PR_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 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 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;
llvm::Function *ModuleInitFunction() override;
llvm::Constant *GetPropertyGetFunction() override;
llvm::Constant *GetPropertySetFunction() override;
llvm::Constant *GetOptimizedPropertySetFunction(bool atomic,
bool copy) override;
llvm::Constant *GetSetStructFunction() override;
llvm::Constant *GetGetStructFunction() override;
llvm::Constant *GetCppAtomicObjectGetFunction() override;
llvm::Constant *GetCppAtomicObjectSetFunction() override;
llvm::Constant *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::CallSite imp = CGF.EmitRuntimeCallOrInvoke(MsgLookupFn, args);
imp->setMetadata(msgSendMDKind, node);
return imp.getInstruction();
}
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::Function *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.
LookupFn->addParamAttr(0, llvm::Attribute::NoCapture);
llvm::Value *args[] = {
EnforceType(Builder, ReceiverPtr.getPointer(), PtrToIdTy),
EnforceType(Builder, cmd, SelectorTy),
EnforceType(Builder, self, IdTy) };
llvm::CallSite slot = CGF.EmitRuntimeCallOrInvoke(LookupFn, args);
slot.setOnlyReadsMemory();
slot->setMetadata(msgSendMDKind, node);
// Load the imp from the slot
llvm::Value *imp = Builder.CreateAlignedLoad(
Builder.CreateStructGEP(nullptr, slot.getInstruction(), 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(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::Constant *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::Constant *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::Constant *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];
template<SectionKind K>
std::string sectionName() {
std::string name(SectionsBaseNames[K]);
if (CGM.getTriple().isOSBinFormatCOFF())
name += "$m";
return name;
}
/// 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.
std::string SymbolForClassRef(StringRef Name, bool isWeak) {
if (isWeak)
return (StringRef("._OBJC_WEAK_REF_CLASS_") + Name).str();
else
return (StringRef("._OBJC_REF_CLASS_") + Name).str();
}
/// Generate the name of a class symbol.
std::string SymbolForClass(StringRef Name) {
return (StringRef("._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::Value *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);
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();
Fields.add(isa);
// 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);
}
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::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)));
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().getQuantity());
}
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().getQuantity());
Ref = GV;
}
EmittedProtocolRef = true;
return CGF.Builder.CreateAlignedLoad(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) {
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;
for (const auto *PI : PD->protocols())
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 = 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(1);
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);
for (auto *s : SectionsBaseNames) {
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*/true, 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
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<ClassReferenceSection>());
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();
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(IvarOffsetPointer, Align);
if (Offset->getType() != PtrDiffTy)
Offset = CGF.Builder.CreateZExtOrBitCast(Offset, PtrDiffTy);
return Offset;
}
void GenerateClass(const ObjCImplementationDecl *OID) override {
ASTContext &Context = CGM.getContext();
// 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("._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();
if (SuperClassDecl) {
auto SuperClassName = SymbolForClass(SuperClassDecl->getNameAsString());
llvm::Constant *SuperClass = TheModule.getNamedGlobal(SuperClassName);
if (!SuperClass)
{
SuperClass = new llvm::GlobalVariable(TheModule, PtrTy, false,
llvm::GlobalValue::ExternalLinkage, nullptr, SuperClassName);
}
classFields.add(llvm::ConstantExpr::getBitCast(SuperClass, 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();
CodeGenTypes &Types = CGM.getTypes();
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,
td.getTypeSizeInBits(Types.ConvertType(ivarTy)) /
CGM.getContext().getCharWidth());
// Alignment will be stored as a base-2 log of the alignment.
int 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) {
ObjCPropertyDecl *prop = propImpl->getPropertyDecl();
auto addIfExists = [&](const ObjCMethodDecl* OMD) {
if (OMD)
InstanceMethods.push_back(OMD);
};
addIfExists(prop->getGetterMethodDecl());
addIfExists(prop->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;
SmallVector<llvm::Constant*, 16> Protocols;
for (const auto *I : classDecl->protocols())
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);
if (CGM.getTriple().isOSBinFormatCOFF()) {
auto Storage = llvm::GlobalValue::DefaultStorageClass;
if (OID->getClassInterface()->hasAttr<DLLImportAttr>())
Storage = llvm::GlobalValue::DLLImportStorageClass;
else if (OID->getClassInterface()->hasAttr<DLLExportAttr>())
Storage = llvm::GlobalValue::DLLExportStorageClass;
cast<llvm::GlobalValue>(classStruct)->setDLLStorageClass(Storage);
}
auto *classRefSymbol = GetClassVar(className);
classRefSymbol->setSection(sectionName<ClassReferenceSection>());
classRefSymbol->setInitializer(llvm::ConstantExpr::getBitCast(classStruct, IdTy));
// 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, "._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"
};
/// 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::CallSite imp;
if (CGM.ReturnTypeUsesSRet(MSI.CallInfo))
imp = CGF.EmitRuntimeCallOrInvoke(MsgLookupFnSRet, args);
else
imp = CGF.EmitRuntimeCallOrInvoke(MsgLookupFn, args);
imp->setMetadata(msgSendMDKind, node);
return imp.getInstruction();
}
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::Constant *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 *CGObjCGNU::GetEHType(QualType T) {
if (T->isObjCIdType() || T->isObjCQualifiedIdType()) {
// With the old ABI, there was only one kind of catchall, which broke
// foreign exceptions. With the new ABI, we use __objc_id_typeinfo as
// a pointer indicating object catchalls, and NULL to indicate real
// catchalls
if (CGM.getLangOpts().ObjCRuntime.isNonFragile()) {
return MakeConstantString("@id");
} else {
return nullptr;
}
}
// All other types should be Objective-C interface pointer types.
const ObjCObjectPointerType *OPT = T->getAs<ObjCObjectPointerType>();
assert(OPT && "Invalid @catch type.");
const ObjCInterfaceDecl *IDecl = OPT->getObjectType()->getInterface();
assert(IDecl && "Invalid @catch type.");
return MakeConstantString(IDecl->getIdentifier()->getName());
}
llvm::Constant *CGObjCGNUstep::GetEHType(QualType T) {
if (usesSEHExceptions)
return CGM.getCXXABI().getAddrOfRTTIDescriptor(T);
if (!CGM.getLangOpts().CPlusPlus)
return CGObjCGNU::GetEHType(T);
// For Objective-C++, we want to provide the ability to catch both C++ and
// Objective-C objects in the same function.
// There's a particular fixed type info for 'id'.
if (T->isObjCIdType() ||
T->isObjCQualifiedIdType()) {
llvm::Constant *IDEHType =
CGM.getModule().getGlobalVariable("__objc_id_type_info");
if (!IDEHType)
IDEHType =
new llvm::GlobalVariable(CGM.getModule(), PtrToInt8Ty,
false,
llvm::GlobalValue::ExternalLinkage,
nullptr, "__objc_id_type_info");
return llvm::ConstantExpr::getBitCast(IDEHType, PtrToInt8Ty);
}
const ObjCObjectPointerType *PT =
T->getAs<ObjCObjectPointerType>();
assert(PT && "Invalid @catch type.");
const ObjCInterfaceType *IT = PT->getInterfaceType();
assert(IT && "Invalid @catch type.");
std::string className = IT->getDecl()->getIdentifier()->getName();
std::string typeinfoName = "__objc_eh_typeinfo_" + className;
// Return the existing typeinfo if it exists
llvm::Constant *typeinfo = TheModule.getGlobalVariable(typeinfoName);
if (typeinfo)
return llvm::ConstantExpr::getBitCast(typeinfo, PtrToInt8Ty);
// Otherwise create it.
// vtable for gnustep::libobjc::__objc_class_type_info
// It's quite ugly hard-coding this. Ideally we'd generate it using the host
// platform's name mangling.
const char *vtableName = "_ZTVN7gnustep7libobjc22__objc_class_type_infoE";
auto *Vtable = TheModule.getGlobalVariable(vtableName);
if (!Vtable) {
Vtable = new llvm::GlobalVariable(TheModule, PtrToInt8Ty, true,
llvm::GlobalValue::ExternalLinkage,
nullptr, vtableName);
}
llvm::Constant *Two = llvm::ConstantInt::get(IntTy, 2);
auto *BVtable = llvm::ConstantExpr::getBitCast(
llvm::ConstantExpr::getGetElementPtr(Vtable->getValueType(), Vtable, Two),
PtrToInt8Ty);
llvm::Constant *typeName =
ExportUniqueString(className, "__objc_eh_typename_");
ConstantInitBuilder builder(CGM);
auto fields = builder.beginStruct();
fields.add(BVtable);
fields.add(typeName);
llvm::Constant *TI =
fields.finishAndCreateGlobal("__objc_eh_typeinfo_" + className,
CGM.getPointerAlign(),
/*constant*/ false,
llvm::GlobalValue::LinkOnceODRLinkage);
return llvm::ConstantExpr::getBitCast(TI, PtrToInt8Ty);
}
/// Generate an NSConstantString object.
ConstantAddress CGObjCGNU::GenerateConstantString(const StringLiteral *SL) {
std::string Str = SL->getString().str();
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);
StringRef StringClass = CGM.getLangOpts().ObjCConstantStringClass;
if (StringClass.empty()) StringClass = "NSConstantString";
std::string Sym = "_OBJC_CLASS_";
Sym += StringClass;
llvm::Constant *isa = TheModule.getNamedGlobal(Sym);
if (!isa)
isa = new llvm::GlobalVariable(TheModule, IdTy, /* isConstant */false,
llvm::GlobalValue::ExternalWeakLinkage, nullptr, Sym);
else if (isa->getType() != PtrToIdTy)
isa = llvm::ConstantExpr::getBitCast(isa, PtrToIdTy);
ConstantInitBuilder Builder(CGM);
auto Fields = Builder.beginStruct();
Fields.add(isa);
Fields.add(MakeConstantString(Str));
Fields.addInt(IntTy, Str.size());
llvm::Constant *ObjCStr =
Fields.finishAndCreateGlobal(".objc_str", Align);
ObjCStr = llvm::ConstantExpr::getBitCast(ObjCStr, PtrToInt8Ty);
ObjCStrings[Str] = ObjCStr;
ConstantStrings.push_back(ObjCStr);
return ConstantAddress(ObjCStr, Align);
}
///Generates a message send where the super is the receiver. This is a message
///send to self with special delivery semantics indicating which class's method
///should be called.
RValue
CGObjCGNU::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) {
CGBuilderTy &Builder = CGF.Builder;
if (CGM.getLangOpts().getGC() == LangOptions::GCOnly) {
if (Sel == RetainSel || Sel == AutoreleaseSel) {
return RValue::get(EnforceType(Builder, Receiver,
CGM.getTypes().ConvertType(ResultType)));
}
if (Sel == ReleaseSel) {
return RValue::get(nullptr);
}
}
llvm::Value *cmd = GetSelector(CGF, Sel);
CallArgList ActualArgs;
ActualArgs.add(RValue::get(EnforceType(Builder, Receiver, IdTy)), ASTIdTy);
ActualArgs.add(RValue::get(cmd), CGF.getContext().getObjCSelType());
ActualArgs.addFrom(CallArgs);
MessageSendInfo MSI = getMessageSendInfo(Method, ResultType, ActualArgs);
llvm::Value *ReceiverClass = nullptr;
bool isV2ABI = isRuntime(ObjCRuntime::GNUstep, 2);
if (isV2ABI) {
ReceiverClass = GetClassNamed(CGF,
Class->getSuperClass()->getNameAsString(), /*isWeak*/false);
if (IsClassMessage) {
// Load the isa pointer of the superclass is this is a class method.
ReceiverClass = Builder.CreateBitCast(ReceiverClass,
llvm::PointerType::getUnqual(IdTy));
ReceiverClass =
Builder.CreateAlignedLoad(ReceiverClass, CGF.getPointerAlign());
}
ReceiverClass = EnforceType(Builder, ReceiverClass, IdTy);
} else {
if (isCategoryImpl) {
llvm::Constant *classLookupFunction = nullptr;
if (IsClassMessage) {
classLookupFunction = CGM.CreateRuntimeFunction(llvm::FunctionType::get(
IdTy, PtrTy, true), "objc_get_meta_class");
} else {
classLookupFunction = CGM.CreateRuntimeFunction(llvm::FunctionType::get(
IdTy, PtrTy, true), "objc_get_class");
}
ReceiverClass = Builder.CreateCall(classLookupFunction,
MakeConstantString(Class->getNameAsString()));
} else {
// Set up global aliases for the metaclass or class pointer if they do not
// already exist. These will are forward-references which will be set to
// pointers to the class and metaclass structure created for the runtime
// load function. To send a message to super, we look up the value of the
// super_class pointer from either the class or metaclass structure.
if (IsClassMessage) {
if (!MetaClassPtrAlias) {
MetaClassPtrAlias = llvm::GlobalAlias::create(
IdTy->getElementType(), 0, llvm::GlobalValue::InternalLinkage,
".objc_metaclass_ref" + Class->getNameAsString(), &TheModule);
}
ReceiverClass = MetaClassPtrAlias;
} else {
if (!ClassPtrAlias) {
ClassPtrAlias = llvm::GlobalAlias::create(
IdTy->getElementType(), 0, llvm::GlobalValue::InternalLinkage,
".objc_class_ref" + Class->getNameAsString(), &TheModule);
}
ReceiverClass = ClassPtrAlias;
}
}
// Cast the pointer to a simplified version of the class structure
llvm::Type *CastTy = llvm::StructType::get(IdTy, IdTy);
ReceiverClass = Builder.CreateBitCast(ReceiverClass,
llvm::PointerType::getUnqual(CastTy));
// Get the superclass pointer
ReceiverClass = Builder.CreateStructGEP(CastTy, ReceiverClass, 1);
// Load the superclass pointer
ReceiverClass =
Builder.CreateAlignedLoad(ReceiverClass, CGF.getPointerAlign());
}
// Construct the structure used to look up the IMP
llvm::StructType *ObjCSuperTy =
llvm::StructType::get(Receiver->getType(), IdTy);
Address ObjCSuper = CGF.CreateTempAlloca(ObjCSuperTy,
CGF.getPointerAlign());
Builder.CreateStore(Receiver,
Builder.CreateStructGEP(ObjCSuper, 0, CharUnits::Zero()));
Builder.CreateStore(ReceiverClass,
Builder.CreateStructGEP(ObjCSuper, 1, CGF.getPointerSize()));
ObjCSuper = EnforceType(Builder, ObjCSuper, PtrToObjCSuperTy);
// Get the IMP
llvm::Value *imp = LookupIMPSuper(CGF, ObjCSuper, cmd, MSI);
imp = EnforceType(Builder, imp, MSI.MessengerType);
llvm::Metadata *impMD[] = {
llvm::MDString::get(VMContext, Sel.getAsString()),
llvm::MDString::get(VMContext, Class->getSuperClass()->getNameAsString()),
llvm::ConstantAsMetadata::get(llvm::ConstantInt::get(
llvm::Type::getInt1Ty(VMContext), IsClassMessage))};
llvm::MDNode *node = llvm::MDNode::get(VMContext, impMD);
CGCallee callee(CGCalleeInfo(), imp);
llvm::Instruction *call;
RValue msgRet = CGF.EmitCall(MSI.CallInfo, callee, Return, ActualArgs, &call);
call->setMetadata(msgSendMDKind, node);
return msgRet;
}
/// Generate code for a message send expression.
RValue
CGObjCGNU::GenerateMessageSend(CodeGenFunction &CGF,
ReturnValueSlot Return,
QualType ResultType,
Selector Sel,
llvm::Value *Receiver,
const CallArgList &CallArgs,
const ObjCInterfaceDecl *Class,
const ObjCMethodDecl *Method) {
CGBuilderTy &Builder = CGF.Builder;
// Strip out message sends to retain / release in GC mode
if (CGM.getLangOpts().getGC() == LangOptions::GCOnly) {
if (Sel == RetainSel || Sel == AutoreleaseSel) {
return RValue::get(EnforceType(Builder, Receiver,
CGM.getTypes().ConvertType(ResultType)));
}
if (Sel == ReleaseSel) {
return RValue::get(nullptr);
}
}
// If the return type is something that goes in an integer register, the
// runtime will handle 0 returns. For other cases, we fill in the 0 value
// ourselves.
//
// The language spec says the result of this kind of message send is
// undefined, but lots of people seem to have forgotten to read that
// paragraph and insist on sending messages to nil that have structure
// returns. With GCC, this generates a random return value (whatever happens
// to be on the stack / in those registers at the time) on most platforms,
// and generates an illegal instruction trap on SPARC. With LLVM it corrupts
// the stack.
bool isPointerSizedReturn = (ResultType->isAnyPointerType() ||
ResultType->isIntegralOrEnumerationType() || ResultType->isVoidType());
llvm::BasicBlock *startBB = nullptr;
llvm::BasicBlock *messageBB = nullptr;
llvm::BasicBlock *continueBB = nullptr;
if (!isPointerSizedReturn) {
startBB = Builder.GetInsertBlock();
messageBB = CGF.createBasicBlock("msgSend");
continueBB = CGF.createBasicBlock("continue");
llvm::Value *isNil = Builder.CreateICmpEQ(Receiver,
llvm::Constant::getNullValue(Receiver->getType()));
Builder.CreateCondBr(isNil, continueBB, messageBB);
CGF.EmitBlock(messageBB);
}
IdTy = cast<llvm::PointerType>(CGM.getTypes().ConvertType(ASTIdTy));
llvm::Value *cmd;
if (Method)
cmd = GetSelector(CGF, Method);
else
cmd = GetSelector(CGF, Sel);
cmd = EnforceType(Builder, cmd, SelectorTy);
Receiver = EnforceType(Builder, Receiver, IdTy);
llvm::Metadata *impMD[] = {
llvm::MDString::get(VMContext, Sel.getAsString()),
llvm::MDString::get(VMContext, Class ? Class->getNameAsString() : ""),
llvm::ConstantAsMetadata::get(llvm::ConstantInt::get(
llvm::Type::getInt1Ty(VMContext), Class != nullptr))};
llvm::MDNode *node = llvm::MDNode::get(VMContext, impMD);
CallArgList ActualArgs;
ActualArgs.add(RValue::get(Receiver), ASTIdTy);
ActualArgs.add(RValue::get(cmd), CGF.getContext().getObjCSelType());
ActualArgs.addFrom(CallArgs);
MessageSendInfo MSI = getMessageSendInfo(Method, ResultType, ActualArgs);
// Get the IMP to call
llvm::Value *imp;
// If we have non-legacy dispatch specified, we try using the objc_msgSend()
// functions. These are not supported on all platforms (or all runtimes on a
// given platform), so we
switch (CGM.getCodeGenOpts().getObjCDispatchMethod()) {
case CodeGenOptions::Legacy:
imp = LookupIMP(CGF, Receiver, cmd, node, MSI);
break;
case CodeGenOptions::Mixed:
case CodeGenOptions::NonLegacy:
if (CGM.ReturnTypeUsesFPRet(ResultType)) {
imp = CGM.CreateRuntimeFunction(llvm::FunctionType::get(IdTy, IdTy, true),
"objc_msgSend_fpret");
} else if (CGM.ReturnTypeUsesSRet(MSI.CallInfo)) {
// The actual types here don't matter - we're going to bitcast the
// function anyway
imp = CGM.CreateRuntimeFunction(llvm::FunctionType::get(IdTy, IdTy, true),
"objc_msgSend_stret");
} else {
imp = CGM.CreateRuntimeFunction(llvm::FunctionType::get(IdTy, IdTy, true),
"objc_msgSend");
}
}
// Reset the receiver in case the lookup modified it
ActualArgs[0] = CallArg(RValue::get(Receiver), ASTIdTy);
imp = EnforceType(Builder, imp, MSI.MessengerType);
llvm::Instruction *call;
CGCallee callee(CGCalleeInfo(), imp);
RValue msgRet = CGF.EmitCall(MSI.CallInfo, callee, Return, ActualArgs, &call);
call->setMetadata(msgSendMDKind, node);
if (!isPointerSizedReturn) {
messageBB = CGF.Builder.GetInsertBlock();
CGF.Builder.CreateBr(continueBB);
CGF.EmitBlock(continueBB);
if (msgRet.isScalar()) {
llvm::Value *v = msgRet.getScalarVal();
llvm::PHINode *phi = Builder.CreatePHI(v->getType(), 2);
phi->addIncoming(v, messageBB);
phi->addIncoming(llvm::Constant::getNullValue(v->getType()), startBB);
msgRet = RValue::get(phi);
} else if (msgRet.isAggregate()) {
Address v = msgRet.getAggregateAddress();
llvm::PHINode *phi = Builder.CreatePHI(v.getType(), 2);
llvm::Type *RetTy = v.getElementType();
Address NullVal = CGF.CreateTempAlloca(RetTy, v.getAlignment(), "null");
CGF.InitTempAlloca(NullVal, llvm::Constant::getNullValue(RetTy));
phi->addIncoming(v.getPointer(), messageBB);
phi->addIncoming(NullVal.getPointer(), startBB);
msgRet = RValue::getAggregate(Address(phi, v.getAlignment()));
} else /* isComplex() */ {
std::pair<llvm::Value*,llvm::Value*> v = msgRet.getComplexVal();
llvm::PHINode *phi = Builder.CreatePHI(v.first->getType(), 2);
phi->addIncoming(v.first, messageBB);
phi->addIncoming(llvm::Constant::getNullValue(v.first->getType()),
startBB);
llvm::PHINode *phi2 = Builder.CreatePHI(v.second->getType(), 2);
phi2->addIncoming(v.second, messageBB);
phi2->addIncoming(llvm::Constant::getNullValue(v.second->getType()),
startBB);
msgRet = RValue::getComplex(phi, phi2);
}
}
return msgRet;
}
/// Generates a MethodList. Used in construction of a objc_class and
/// objc_category structures.
llvm::Constant *CGObjCGNU::
GenerateMethodList(StringRef ClassName,
StringRef CategoryName,
ArrayRef<const ObjCMethodDecl*> Methods,
bool isClassMethodList) {
if (Methods.empty())
return NULLPtr;
ConstantInitBuilder Builder(CGM);
auto MethodList = Builder.beginStruct();
MethodList.addNullPointer(CGM.Int8PtrTy);
MethodList.addInt(Int32Ty, Methods.size());
// Get the method structure type.
llvm::StructType *ObjCMethodTy =
llvm::StructType::get(CGM.getLLVMContext(), {
PtrToInt8Ty, // Really a selector, but the runtime creates it us.
PtrToInt8Ty, // Method types
IMPTy // Method pointer
});
bool isV2ABI = isRuntime(ObjCRuntime::GNUstep, 2);
if (isV2ABI) {
// size_t size;
llvm::DataLayout td(&TheModule);
MethodList.addInt(SizeTy, td.getTypeSizeInBits(ObjCMethodTy) /
CGM.getContext().getCharWidth());
ObjCMethodTy =
llvm::StructType::get(CGM.getLLVMContext(), {
IMPTy, // Method pointer
PtrToInt8Ty, // Selector
PtrToInt8Ty // Extended type encoding
});
} else {
ObjCMethodTy =
llvm::StructType::get(CGM.getLLVMContext(), {
PtrToInt8Ty, // Really a selector, but the runtime creates it us.
PtrToInt8Ty, // Method types
IMPTy // Method pointer
});
}
auto MethodArray = MethodList.beginArray();
ASTContext &Context = CGM.getContext();
for (const auto *OMD : Methods) {
llvm::Constant *FnPtr =
TheModule.getFunction(SymbolNameForMethod(ClassName, CategoryName,
OMD->getSelector(),
isClassMethodList));
assert(FnPtr && "Can't generate metadata for method that doesn't exist");
auto Method = MethodArray.beginStruct(ObjCMethodTy);
if (isV2ABI) {
Method.addBitCast(FnPtr, IMPTy);
Method.add(GetConstantSelector(OMD->getSelector(),
Context.getObjCEncodingForMethodDecl(OMD)));
Method.add(MakeConstantString(Context.getObjCEncodingForMethodDecl(OMD, true)));
} else {
Method.add(MakeConstantString(OMD->getSelector().getAsString()));
Method.add(MakeConstantString(Context.getObjCEncodingForMethodDecl(OMD)));
Method.addBitCast(FnPtr, IMPTy);
}
Method.finishAndAddTo(MethodArray);
}
MethodArray.finishAndAddTo(MethodList);
// Create an instance of the structure
return MethodList.finishAndCreateGlobal(".objc_method_list",
CGM.getPointerAlign());
}
/// Generates an IvarList. Used in construction of a objc_class.
llvm::Constant *CGObjCGNU::
GenerateIvarList(ArrayRef<llvm::Constant *> IvarNames,
ArrayRef<llvm::Constant *> IvarTypes,
ArrayRef<llvm::Constant *> IvarOffsets,
ArrayRef<llvm::Constant *> IvarAlign,
ArrayRef<Qualifiers::ObjCLifetime> IvarOwnership) {
if (IvarNames.empty())
return NULLPtr;
ConstantInitBuilder Builder(CGM);
// Structure containing array count followed by array.
auto IvarList = Builder.beginStruct();
IvarList.addInt(IntTy, (int)IvarNames.size());
// Get the ivar structure type.
llvm::StructType *ObjCIvarTy =
llvm::StructType::get(PtrToInt8Ty, PtrToInt8Ty, IntTy);
// Array of ivar structures.
auto Ivars = IvarList.beginArray(ObjCIvarTy);
for (unsigned int i = 0, e = IvarNames.size() ; i < e ; i++) {
auto Ivar = Ivars.beginStruct(ObjCIvarTy);
Ivar.add(IvarNames[i]);
Ivar.add(IvarTypes[i]);
Ivar.add(IvarOffsets[i]);
Ivar.finishAndAddTo(Ivars);
}
Ivars.finishAndAddTo(IvarList);
// Create an instance of the structure
return IvarList.finishAndCreateGlobal(".objc_ivar_list",
CGM.getPointerAlign());
}
/// Generate a class structure
llvm::Constant *CGObjCGNU::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) {
// Set up the class structure
// Note: Several of these are char*s when they should be ids. This is
// because the runtime performs this translation on load.
//
// Fields marked New ABI are part of the GNUstep runtime. We emit them
// anyway; the classes will still work with the GNU runtime, they will just
// be ignored.
llvm::StructType *ClassTy = llvm::StructType::get(
PtrToInt8Ty, // isa
PtrToInt8Ty, // super_class
PtrToInt8Ty, // name
LongTy, // version
LongTy, // info
LongTy, // instance_size
IVars->getType(), // ivars
Methods->getType(), // methods
// These are all filled in by the runtime, so we pretend
PtrTy, // dtable
PtrTy, // subclass_list
PtrTy, // sibling_class
PtrTy, // protocols
PtrTy, // gc_object_type
// New ABI:
LongTy, // abi_version
IvarOffsets->getType(), // ivar_offsets
Properties->getType(), // properties
IntPtrTy, // strong_pointers
IntPtrTy // weak_pointers
);
ConstantInitBuilder Builder(CGM);
auto Elements = Builder.beginStruct(ClassTy);
// Fill in the structure
// isa
Elements.addBitCast(MetaClass, PtrToInt8Ty);
// super_class
Elements.add(SuperClass);
// name
Elements.add(MakeConstantString(Name, ".class_name"));
// version
Elements.addInt(LongTy, 0);
// info
Elements.addInt(LongTy, info);
// instance_size
if (isMeta) {
llvm::DataLayout td(&TheModule);
Elements.addInt(LongTy,
td.getTypeSizeInBits(ClassTy) /
CGM.getContext().getCharWidth());
} else
Elements.add(InstanceSize);
// ivars
Elements.add(IVars);
// methods
Elements.add(Methods);
// These are all filled in by the runtime, so we pretend
// dtable
Elements.add(NULLPtr);
// subclass_list
Elements.add(NULLPtr);
// sibling_class
Elements.add(NULLPtr);
// protocols
Elements.addBitCast(Protocols, PtrTy);
// gc_object_type
Elements.add(NULLPtr);
// abi_version
Elements.addInt(LongTy, ClassABIVersion);
// ivar_offsets
Elements.add(IvarOffsets);
// properties
Elements.add(Properties);
// strong_pointers
Elements.add(StrongIvarBitmap);
// weak_pointers
Elements.add(WeakIvarBitmap);
// Create an instance of the structure
// This is now an externally visible symbol, so that we can speed up class
// messages in the next ABI. We may already have some weak references to
// this, so check and fix them properly.
std::string ClassSym((isMeta ? "_OBJC_METACLASS_": "_OBJC_CLASS_") +
std::string(Name));
llvm::GlobalVariable *ClassRef = TheModule.getNamedGlobal(ClassSym);
llvm::Constant *Class =
Elements.finishAndCreateGlobal(ClassSym, CGM.getPointerAlign(), false,
llvm::GlobalValue::ExternalLinkage);
if (ClassRef) {
ClassRef->replaceAllUsesWith(llvm::ConstantExpr::getBitCast(Class,
ClassRef->getType()));
ClassRef->removeFromParent();
Class->setName(ClassSym);
}
return Class;
}
llvm::Constant *CGObjCGNU::
GenerateProtocolMethodList(ArrayRef<const ObjCMethodDecl*> Methods) {
// Get the method structure type.
llvm::StructType *ObjCMethodDescTy =
llvm::StructType::get(CGM.getLLVMContext(), { PtrToInt8Ty, PtrToInt8Ty });
ASTContext &Context = CGM.getContext();
ConstantInitBuilder Builder(CGM);
auto MethodList = Builder.beginStruct();
MethodList.addInt(IntTy, Methods.size());
auto MethodArray = MethodList.beginArray(ObjCMethodDescTy);
for (auto *M : Methods) {
auto Method = MethodArray.beginStruct(ObjCMethodDescTy);
Method.add(MakeConstantString(M->getSelector().getAsString()));
Method.add(MakeConstantString(Context.getObjCEncodingForMethodDecl(M)));
Method.finishAndAddTo(MethodArray);
}
MethodArray.finishAndAddTo(MethodList);
return MethodList.finishAndCreateGlobal(".objc_method_list",
CGM.getPointerAlign());
}
// Create the protocol list structure used in classes, categories and so on
llvm::Constant *
CGObjCGNU::GenerateProtocolList(ArrayRef<std::string> Protocols) {
ConstantInitBuilder Builder(CGM);
auto ProtocolList = Builder.beginStruct();
ProtocolList.add(NULLPtr);
ProtocolList.addInt(LongTy, Protocols.size());
auto Elements = ProtocolList.beginArray(PtrToInt8Ty);
for (const std::string *iter = Protocols.begin(), *endIter = Protocols.end();
iter != endIter ; iter++) {
llvm::Constant *protocol = nullptr;
llvm::StringMap<llvm::Constant*>::iterator value =
ExistingProtocols.find(*iter);
if (value == ExistingProtocols.end()) {
protocol = GenerateEmptyProtocol(*iter);
} else {
protocol = value->getValue();
}
Elements.addBitCast(protocol, PtrToInt8Ty);
}
Elements.finishAndAddTo(ProtocolList);
return ProtocolList.finishAndCreateGlobal(".objc_protocol_list",
CGM.getPointerAlign());
}
llvm::Value *CGObjCGNU::GenerateProtocolRef(CodeGenFunction &CGF,
const ObjCProtocolDecl *PD) {
llvm::Constant *&protocol = ExistingProtocols[PD->getNameAsString()];
if (!protocol)
GenerateProtocol(PD);
llvm::Type *T =
CGM.getTypes().ConvertType(CGM.getContext().getObjCProtoType());
return CGF.Builder.CreateBitCast(protocol, llvm::PointerType::getUnqual(T));
}
llvm::Constant *
CGObjCGNU::GenerateEmptyProtocol(StringRef ProtocolName) {
llvm::Constant *ProtocolList = GenerateProtocolList({});
llvm::Constant *MethodList = GenerateProtocolMethodList({});
MethodList = llvm::ConstantExpr::getBitCast(MethodList, PtrToInt8Ty);
// Protocols are objects containing lists of the methods implemented and
// protocols adopted.
ConstantInitBuilder Builder(CGM);
auto Elements = Builder.beginStruct();
// The isa pointer must be set to a magic number so the runtime knows it's
// the correct layout.
Elements.add(llvm::ConstantExpr::getIntToPtr(
llvm::ConstantInt::get(Int32Ty, ProtocolVersion), IdTy));
Elements.add(MakeConstantString(ProtocolName, ".objc_protocol_name"));
Elements.add(ProtocolList); /* .protocol_list */
Elements.add(MethodList); /* .instance_methods */
Elements.add(MethodList); /* .class_methods */
Elements.add(MethodList); /* .optional_instance_methods */
Elements.add(MethodList); /* .optional_class_methods */
Elements.add(NULLPtr); /* .properties */
Elements.add(NULLPtr); /* .optional_properties */
return Elements.finishAndCreateGlobal(SymbolForProtocol(ProtocolName),
CGM.getPointerAlign());
}
void CGObjCGNU::GenerateProtocol(const ObjCProtocolDecl *PD) {
std::string ProtocolName = PD->getNameAsString();
// Use the protocol definition, if there is one.
if (const ObjCProtocolDecl *Def = PD->getDefinition())
PD = Def;
SmallVector<std::string, 16> Protocols;
for (const auto *PI : PD->protocols())
Protocols.push_back(PI->getNameAsString());
SmallVector<const ObjCMethodDecl*, 16> InstanceMethods;
SmallVector<const ObjCMethodDecl*, 16> OptionalInstanceMethods;
for (const auto *I : PD->instance_methods())
if (I->isOptional())
OptionalInstanceMethods.push_back(I);
else
InstanceMethods.push_back(I);
// Collect information about class methods:
SmallVector<const ObjCMethodDecl*, 16> ClassMethods;
SmallVector<const ObjCMethodDecl*, 16> OptionalClassMethods;
for (const auto *I : PD->class_methods())
if (I->isOptional())
OptionalClassMethods.push_back(I);
else
ClassMethods.push_back(I);
llvm::Constant *ProtocolList = GenerateProtocolList(Protocols);
llvm::Constant *InstanceMethodList =
GenerateProtocolMethodList(InstanceMethods);
llvm::Constant *ClassMethodList =
GenerateProtocolMethodList(ClassMethods);
llvm::Constant *OptionalInstanceMethodList =
GenerateProtocolMethodList(OptionalInstanceMethods);
llvm::Constant *OptionalClassMethodList =
GenerateProtocolMethodList(OptionalClassMethods);
// Property metadata: name, attributes, isSynthesized, setter name, setter
// types, getter name, getter types.
// The isSynthesized value is always set to 0 in a protocol. It exists to
// simplify the runtime library by allowing it to use the same data
// structures for protocol metadata everywhere.
llvm::Constant *PropertyList =
GeneratePropertyList(nullptr, PD, false, false);
llvm::Constant *OptionalPropertyList =
GeneratePropertyList(nullptr, PD, false, true);
// Protocols are objects containing lists of the methods implemented and
// protocols adopted.
// The isa pointer must be set to a magic number so the runtime knows it's
// the correct layout.
ConstantInitBuilder Builder(CGM);
auto Elements = Builder.beginStruct();
Elements.add(
llvm::ConstantExpr::getIntToPtr(
llvm::ConstantInt::get(Int32Ty, ProtocolVersion), IdTy));
Elements.add(MakeConstantString(ProtocolName));
Elements.add(ProtocolList);
Elements.add(InstanceMethodList);
Elements.add(ClassMethodList);
Elements.add(OptionalInstanceMethodList);
Elements.add(OptionalClassMethodList);
Elements.add(PropertyList);
Elements.add(OptionalPropertyList);
ExistingProtocols[ProtocolName] =
llvm::ConstantExpr::getBitCast(
Elements.finishAndCreateGlobal(".objc_protocol", CGM.getPointerAlign()),
IdTy);
}
void CGObjCGNU::GenerateProtocolHolderCategory() {
// Collect information about instance methods
ConstantInitBuilder Builder(CGM);
auto Elements = Builder.beginStruct();
const std::string ClassName = "__ObjC_Protocol_Holder_Ugly_Hack";
const std::string CategoryName = "AnotherHack";
Elements.add(MakeConstantString(CategoryName));
Elements.add(MakeConstantString(ClassName));
// Instance method list
Elements.addBitCast(GenerateMethodList(
ClassName, CategoryName, {}, false), PtrTy);
// Class method list
Elements.addBitCast(GenerateMethodList(
ClassName, CategoryName, {}, true), PtrTy);
// Protocol list
ConstantInitBuilder ProtocolListBuilder(CGM);
auto ProtocolList = ProtocolListBuilder.beginStruct();
ProtocolList.add(NULLPtr);
ProtocolList.addInt(LongTy, ExistingProtocols.size());
auto ProtocolElements = ProtocolList.beginArray(PtrTy);
for (auto iter = ExistingProtocols.begin(), endIter = ExistingProtocols.end();
iter != endIter ; iter++) {
ProtocolElements.addBitCast(iter->getValue(), PtrTy);
}
ProtocolElements.finishAndAddTo(ProtocolList);
Elements.addBitCast(
ProtocolList.finishAndCreateGlobal(".objc_protocol_list",
CGM.getPointerAlign()),
PtrTy);
Categories.push_back(llvm::ConstantExpr::getBitCast(
Elements.finishAndCreateGlobal("", CGM.getPointerAlign()),
PtrTy));
}
/// 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 *CGObjCGNU::MakeBitField(ArrayRef<bool> bits) {
int bitCount = bits.size();
int ptrBits = CGM.getDataLayout().getPointerSizeInBits();
if (bitCount < ptrBits) {
uint64_t val = 1;
for (int i=0 ; i<bitCount ; ++i) {
if (bits[i]) val |= 1ULL<<(i+1);
}
return llvm::ConstantInt::get(IntPtrTy, val);
}
SmallVector<llvm::Constant *, 8> values;
int v=0;
while (v < bitCount) {
int32_t word = 0;
for (int i=0 ; (i<32) && (v<bitCount) ; ++i) {
if (bits[v]) word |= 1<<i;
v++;
}
values.push_back(llvm::ConstantInt::get(Int32Ty, word));
}
ConstantInitBuilder builder(CGM);
auto fields = builder.beginStruct();
fields.addInt(Int32Ty, values.size());
auto array = fields.beginArray();
for (auto v : values) array.add(v);
array.finishAndAddTo(fields);
llvm::Constant *GS =
fields.finishAndCreateGlobal("", CharUnits::fromQuantity(4));
llvm::Constant *ptr = llvm::ConstantExpr::getPtrToInt(GS, IntPtrTy);
return ptr;
}
void CGObjCGNU::GenerateCategory(const ObjCCategoryImplDecl *OCD) {
const ObjCInterfaceDecl *Class = OCD->getClassInterface();
std::string ClassName = Class->getNameAsString();
std::string CategoryName = OCD->getNameAsString();
// Collect the names of referenced protocols
SmallVector<std::string, 16> Protocols;
const ObjCCategoryDecl *CatDecl = OCD->getCategoryDecl();
const ObjCList<ObjCProtocolDecl> &Protos = CatDecl->getReferencedProtocols();
for (ObjCList<ObjCProtocolDecl>::iterator I = Protos.begin(),
E = Protos.end(); I != E; ++I)
Protocols.push_back((*I)->getNameAsString());
ConstantInitBuilder Builder(CGM);
auto Elements = Builder.beginStruct();
Elements.add(MakeConstantString(CategoryName));
Elements.add(MakeConstantString(ClassName));
// Instance method list
SmallVector<ObjCMethodDecl*, 16> InstanceMethods;
InstanceMethods.insert(InstanceMethods.begin(), OCD->instmeth_begin(),
OCD->instmeth_end());
Elements.addBitCast(
GenerateMethodList(ClassName, CategoryName, InstanceMethods, false),
PtrTy);
// Class method list
SmallVector<ObjCMethodDecl*, 16> ClassMethods;
ClassMethods.insert(ClassMethods.begin(), OCD->classmeth_begin(),
OCD->classmeth_end());
Elements.addBitCast(
GenerateMethodList(ClassName, CategoryName, ClassMethods, true),
PtrTy);
// Protocol list
Elements.addBitCast(GenerateProtocolList(Protocols), PtrTy);
if (isRuntime(ObjCRuntime::GNUstep, 2)) {
const ObjCCategoryDecl *Category =
Class->FindCategoryDeclaration(OCD->getIdentifier());
if (Category) {
// Instance properties
Elements.addBitCast(GeneratePropertyList(OCD, Category, false), PtrTy);
// Class properties
Elements.addBitCast(GeneratePropertyList(OCD, Category, true), PtrTy);
} else {
Elements.addNullPointer(PtrTy);
Elements.addNullPointer(PtrTy);
}
}
Categories.push_back(llvm::ConstantExpr::getBitCast(
Elements.finishAndCreateGlobal(
std::string(".objc_category_")+ClassName+CategoryName,
CGM.getPointerAlign()),
PtrTy));
}
llvm::Constant *CGObjCGNU::GeneratePropertyList(const Decl *Container,
const ObjCContainerDecl *OCD,
bool isClassProperty,
bool protocolOptionalProperties) {
SmallVector<const ObjCPropertyDecl *, 16> Properties;
llvm::SmallPtrSet<const IdentifierInfo*, 16> PropertySet;
bool isProtocol = isa<ObjCProtocolDecl>(OCD);
ASTContext &Context = CGM.getContext();
std::function<void(const ObjCProtocolDecl *Proto)> collectProtocolProperties
= [&](const ObjCProtocolDecl *Proto) {
for (const auto *P : Proto->protocols())
collectProtocolProperties(P);
for (const auto *PD : Proto->properties()) {
if (isClassProperty != PD->isClassProperty())
continue;
// Skip any properties that are declared in protocols that this class
// conforms to but are not actually implemented by this class.
if (!isProtocol && !Context.getObjCPropertyImplDeclForPropertyDecl(PD, Container))
continue;
if (!PropertySet.insert(PD->getIdentifier()).second)
continue;
Properties.push_back(PD);
}
};
if (const ObjCInterfaceDecl *OID = dyn_cast<ObjCInterfaceDecl>(OCD))
for (const ObjCCategoryDecl *ClassExt : OID->known_extensions())
for (auto *PD : ClassExt->properties()) {
if (isClassProperty != PD->isClassProperty())
continue;
PropertySet.insert(PD->getIdentifier());
Properties.push_back(PD);
}
for (const auto *PD : OCD->properties()) {
if (isClassProperty != PD->isClassProperty())
continue;
// If we're generating a list for a protocol, skip optional / required ones
// when generating the other list.
if (isProtocol && (protocolOptionalProperties != PD->isOptional()))
continue;
// Don't emit duplicate metadata for properties that were already in a
// class extension.
if (!PropertySet.insert(PD->getIdentifier()).second)
continue;
Properties.push_back(PD);
}
if (const ObjCInterfaceDecl *OID = dyn_cast<ObjCInterfaceDecl>(OCD))
for (const auto *P : OID->all_referenced_protocols())
collectProtocolProperties(P);
else if (const ObjCCategoryDecl *CD = dyn_cast<ObjCCategoryDecl>(OCD))
for (const auto *P : CD->protocols())
collectProtocolProperties(P);
auto numProperties = Properties.size();
if (numProperties == 0)
return NULLPtr;
ConstantInitBuilder builder(CGM);
auto propertyList = builder.beginStruct();
auto properties = PushPropertyListHeader(propertyList, numProperties);
// Add all of the property methods need adding to the method list and to the
// property metadata list.
for (auto *property : Properties) {
bool isSynthesized = false;
bool isDynamic = false;
if (!isProtocol) {
auto *propertyImpl = Context.getObjCPropertyImplDeclForPropertyDecl(property, Container);
if (propertyImpl) {
isSynthesized = (propertyImpl->getPropertyImplementation() ==
ObjCPropertyImplDecl::Synthesize);
isDynamic = (propertyImpl->getPropertyImplementation() ==
ObjCPropertyImplDecl::Dynamic);
}
}
PushProperty(properties, property, Container, isSynthesized, isDynamic);
}
properties.finishAndAddTo(propertyList);
return propertyList.finishAndCreateGlobal(".objc_property_list",
CGM.getPointerAlign());
}
void CGObjCGNU::RegisterAlias(const ObjCCompatibleAliasDecl *OAD) {
// Get the class declaration for which the alias is specified.
ObjCInterfaceDecl *ClassDecl =
const_cast<ObjCInterfaceDecl *>(OAD->getClassInterface());
ClassAliases.emplace_back(ClassDecl->getNameAsString(),
OAD->getNameAsString());
}
void CGObjCGNU::GenerateClass(const ObjCImplementationDecl *OID) {
ASTContext &Context = CGM.getContext();
// Get the superclass name.
const ObjCInterfaceDecl * SuperClassDecl =
OID->getClassInterface()->getSuperClass();
std::string SuperClassName;
if (SuperClassDecl) {
SuperClassName = SuperClassDecl->getNameAsString();
EmitClassRef(SuperClassName);
}
// Get the class name
ObjCInterfaceDecl *ClassDecl =
const_cast<ObjCInterfaceDecl *>(OID->getClassInterface());
std::string ClassName = ClassDecl->getNameAsString();
// Emit the symbol that is used to generate linker errors if this class is
// referenced in other modules but not declared.
std::string classSymbolName = "__objc_class_name_" + ClassName;
if (auto *symbol = TheModule.getGlobalVariable(classSymbolName)) {
symbol->setInitializer(llvm::ConstantInt::get(LongTy, 0));
} else {
new llvm::GlobalVariable(TheModule, LongTy, false,
llvm::GlobalValue::ExternalLinkage,
llvm::ConstantInt::get(LongTy, 0),
classSymbolName);
}
// Get the size of instances.
int instanceSize =
Context.getASTObjCImplementationLayout(OID).getSize().getQuantity();
// Collect information about instance variables.
SmallVector<llvm::Constant*, 16> IvarNames;
SmallVector<llvm::Constant*, 16> IvarTypes;
SmallVector<llvm::Constant*, 16> IvarOffsets;
SmallVector<llvm::Constant*, 16> IvarAligns;
SmallVector<Qualifiers::ObjCLifetime, 16> IvarOwnership;
ConstantInitBuilder IvarOffsetBuilder(CGM);
auto IvarOffsetValues = IvarOffsetBuilder.beginArray(PtrToIntTy);
SmallVector<bool, 16> WeakIvars;
SmallVector<bool, 16> StrongIvars;
int superInstanceSize = !SuperClassDecl ? 0 :
Context.getASTObjCInterfaceLayout(SuperClassDecl).getSize().getQuantity();
// For non-fragile ivars, set the instance size to 0 - {the size of just this
// class}. The runtime will then set this to the correct value on load.
if (CGM.getLangOpts().ObjCRuntime.isNonFragile()) {
instanceSize = 0 - (instanceSize - superInstanceSize);
}
for (const ObjCIvarDecl *IVD = ClassDecl->all_declared_ivar_begin(); IVD;
IVD = IVD->getNextIvar()) {
// Store the name
IvarNames.push_back(MakeConstantString(IVD->getNameAsString()));
// Get the type encoding for this ivar
std::string TypeStr;
Context.getObjCEncodingForType(IVD->getType(), TypeStr, IVD);
IvarTypes.push_back(MakeConstantString(TypeStr));
IvarAligns.push_back(llvm::ConstantInt::get(IntTy,
Context.getTypeSize(IVD->getType())));
// Get the offset
uint64_t BaseOffset = ComputeIvarBaseOffset(CGM, OID, IVD);
uint64_t Offset = BaseOffset;
if (CGM.getLangOpts().ObjCRuntime.isNonFragile()) {
Offset = BaseOffset - superInstanceSize;
}
llvm::Constant *OffsetValue = llvm::ConstantInt::get(IntTy, Offset);
// Create the direct offset value
std::string OffsetName = "__objc_ivar_offset_value_" + ClassName +"." +
IVD->getNameAsString();
llvm::GlobalVariable *OffsetVar = TheModule.getGlobalVariable(OffsetName);
if (OffsetVar) {
OffsetVar->setInitializer(OffsetValue);
// If this is the real definition, change its linkage type so that
// different modules will use this one, rather than their private
// copy.
OffsetVar->setLinkage(llvm::GlobalValue::ExternalLinkage);
} else
OffsetVar = new llvm::GlobalVariable(TheModule, Int32Ty,
false, llvm::GlobalValue::ExternalLinkage,
OffsetValue, OffsetName);
IvarOffsets.push_back(OffsetValue);
IvarOffsetValues.add(OffsetVar);
Qualifiers::ObjCLifetime lt = IVD->getType().getQualifiers().getObjCLifetime();
IvarOwnership.push_back(lt);
switch (lt) {
case Qualifiers::OCL_Strong:
StrongIvars.push_back(true);
WeakIvars.push_back(false);
break;
case Qualifiers::OCL_Weak:
StrongIvars.push_back(false);
WeakIvars.push_back(true);
break;
default:
StrongIvars.push_back(false);
WeakIvars.push_back(false);
}
}
llvm::Constant *StrongIvarBitmap = MakeBitField(StrongIvars);
llvm::Constant *WeakIvarBitmap = MakeBitField(WeakIvars);
llvm::GlobalVariable *IvarOffsetArray =
IvarOffsetValues.finishAndCreateGlobal(".ivar.offsets",
CGM.getPointerAlign());
// Collect information about instance methods
SmallVector<const ObjCMethodDecl*, 16> InstanceMethods;
InstanceMethods.insert(InstanceMethods.begin(), OID->instmeth_begin(),
OID->instmeth_end());
SmallVector<const ObjCMethodDecl*, 16> ClassMethods;
ClassMethods.insert(ClassMethods.begin(), OID->classmeth_begin(),
OID->classmeth_end());
// Collect the same information about synthesized properties, which don't
// show up in the instance method lists.
for (auto *propertyImpl : OID->property_impls())
if (propertyImpl->getPropertyImplementation() ==
ObjCPropertyImplDecl::Synthesize) {
ObjCPropertyDecl *property = propertyImpl->getPropertyDecl();
auto addPropertyMethod = [&](const ObjCMethodDecl *accessor) {
if (accessor)
InstanceMethods.push_back(accessor);
};
addPropertyMethod(property->getGetterMethodDecl());
addPropertyMethod(property->getSetterMethodDecl());
}
llvm::Constant *Properties = GeneratePropertyList(OID, ClassDecl);
// Collect the names of referenced protocols
SmallVector<std::string, 16> Protocols;
for (const auto *I : ClassDecl->protocols())
Protocols.push_back(I->getNameAsString());
// Get the superclass pointer.
llvm::Constant *SuperClass;
if (!SuperClassName.empty()) {
SuperClass = MakeConstantString(SuperClassName, ".super_class_name");
} else {
SuperClass = llvm::ConstantPointerNull::get(PtrToInt8Ty);
}
// Empty vector used to construct empty method lists
SmallVector<llvm::Constant*, 1> empty;
// Generate the method and instance variable lists
llvm::Constant *MethodList = GenerateMethodList(ClassName, "",
InstanceMethods, false);
llvm::Constant *ClassMethodList = GenerateMethodList(ClassName, "",
ClassMethods, true);
llvm::Constant *IvarList = GenerateIvarList(IvarNames, IvarTypes,
IvarOffsets, IvarAligns, IvarOwnership);
// Irrespective of whether we are compiling for a fragile or non-fragile ABI,
// we emit a symbol containing the offset for each ivar in the class. This
// allows code compiled for the non-Fragile ABI to inherit from code compiled
// for the legacy ABI, without causing problems. The converse is also
// possible, but causes all ivar accesses to be fragile.
// Offset pointer for getting at the correct field in the ivar list when
// setting up the alias. These are: The base address for the global, the
// ivar array (second field), the ivar in this list (set for each ivar), and
// the offset (third field in ivar structure)
llvm::Type *IndexTy = Int32Ty;
llvm::Constant *offsetPointerIndexes[] = {Zeros[0],
llvm::ConstantInt::get(IndexTy, ClassABIVersion > 1 ? 2 : 1), nullptr,
llvm::ConstantInt::get(IndexTy, ClassABIVersion > 1 ? 3 : 2) };
unsigned ivarIndex = 0;
for (const ObjCIvarDecl *IVD = ClassDecl->all_declared_ivar_begin(); IVD;
IVD = IVD->getNextIvar()) {
const std::string Name = GetIVarOffsetVariableName(ClassDecl, IVD);
offsetPointerIndexes[2] = llvm::ConstantInt::get(IndexTy, ivarIndex);
// Get the correct ivar field
llvm::Constant *offsetValue = llvm::ConstantExpr::getGetElementPtr(
cast<llvm::GlobalVariable>(IvarList)->getValueType(), IvarList,
offsetPointerIndexes);
// Get the existing variable, if one exists.
llvm::GlobalVariable *offset = TheModule.getNamedGlobal(Name);
if (offset) {
offset->setInitializer(offsetValue);
// If this is the real definition, change its linkage type so that
// different modules will use this one, rather than their private
// copy.
offset->setLinkage(llvm::GlobalValue::ExternalLinkage);
} else
// Add a new alias if there isn't one already.
new llvm::GlobalVariable(TheModule, offsetValue->getType(),
false, llvm::GlobalValue::ExternalLinkage, offsetValue, Name);
++ivarIndex;
}
llvm::Constant *ZeroPtr = llvm::ConstantInt::get(IntPtrTy, 0);
//Generate metaclass for class methods
llvm::Constant *MetaClassStruct = GenerateClassStructure(
NULLPtr, NULLPtr, 0x12L, ClassName.c_str(), nullptr, Zeros[0],
NULLPtr, ClassMethodList, NULLPtr, NULLPtr,
GeneratePropertyList(OID, ClassDecl, true), ZeroPtr, ZeroPtr, true);
CGM.setGVProperties(cast<llvm::GlobalValue>(MetaClassStruct),
OID->getClassInterface());
// Generate the class structure
llvm::Constant *ClassStruct = GenerateClassStructure(
MetaClassStruct, SuperClass, 0x11L, ClassName.c_str(), nullptr,
llvm::ConstantInt::get(LongTy, instanceSize), IvarList, MethodList,
GenerateProtocolList(Protocols), IvarOffsetArray, Properties,
StrongIvarBitmap, WeakIvarBitmap);
CGM.setGVProperties(cast<llvm::GlobalValue>(ClassStruct),
OID->getClassInterface());
// Resolve the class aliases, if they exist.
if (ClassPtrAlias) {
ClassPtrAlias->replaceAllUsesWith(
llvm::ConstantExpr::getBitCast(ClassStruct, IdTy));
ClassPtrAlias->eraseFromParent();
ClassPtrAlias = nullptr;
}
if (MetaClassPtrAlias) {
MetaClassPtrAlias->replaceAllUsesWith(
llvm::ConstantExpr::getBitCast(MetaClassStruct, IdTy));
MetaClassPtrAlias->eraseFromParent();
MetaClassPtrAlias = nullptr;
}
// Add class structure to list to be added to the symtab later
ClassStruct = llvm::ConstantExpr::getBitCast(ClassStruct, PtrToInt8Ty);
Classes.push_back(ClassStruct);
}
llvm::Function *CGObjCGNU::ModuleInitFunction() {
// Only emit an ObjC load function if no Objective-C stuff has been called
if (Classes.empty() && Categories.empty() && ConstantStrings.empty() &&
ExistingProtocols.empty() && SelectorTable.empty())
return nullptr;
// Add all referenced protocols to a category.
GenerateProtocolHolderCategory();
llvm::StructType *selStructTy =
dyn_cast<llvm::StructType>(SelectorTy->getElementType());
llvm::Type *selStructPtrTy = SelectorTy;
if (!selStructTy) {
selStructTy = llvm::StructType::get(CGM.getLLVMContext(),
{ PtrToInt8Ty, PtrToInt8Ty });
selStructPtrTy = llvm::PointerType::getUnqual(selStructTy);
}
// Generate statics list:
llvm::Constant *statics = NULLPtr;
if (!ConstantStrings.empty()) {
llvm::GlobalVariable *fileStatics = [&] {
ConstantInitBuilder builder(CGM);
auto staticsStruct = builder.beginStruct();
StringRef stringClass = CGM.getLangOpts().ObjCConstantStringClass;
if (stringClass.empty()) stringClass = "NXConstantString";
staticsStruct.add(MakeConstantString(stringClass,
".objc_static_class_name"));
auto array = staticsStruct.beginArray();
array.addAll(ConstantStrings);
array.add(NULLPtr);
array.finishAndAddTo(staticsStruct);
return staticsStruct.finishAndCreateGlobal(".objc_statics",
CGM.getPointerAlign());
}();
ConstantInitBuilder builder(CGM);
auto allStaticsArray = builder.beginArray(fileStatics->getType());
allStaticsArray.add(fileStatics);
allStaticsArray.addNullPointer(fileStatics->getType());
statics = allStaticsArray.finishAndCreateGlobal(".objc_statics_ptr",
CGM.getPointerAlign());
statics = llvm::ConstantExpr::getBitCast(statics, PtrTy);
}
// Array of classes, categories, and constant objects.
SmallVector<llvm::GlobalAlias*, 16> selectorAliases;
unsigned selectorCount;
// Pointer to an array of selectors used in this module.
llvm::GlobalVariable *selectorList = [&] {
ConstantInitBuilder builder(CGM);
auto selectors = builder.beginArray(selStructTy);
auto &table = SelectorTable; // MSVC workaround
for (auto &entry : table) {
std::string selNameStr = entry.first.getAsString();
llvm::Constant *selName = ExportUniqueString(selNameStr, ".objc_sel_name");
for (TypedSelector &sel : entry.second) {
llvm::Constant *selectorTypeEncoding = NULLPtr;
if (!sel.first.empty())
selectorTypeEncoding =
MakeConstantString(sel.first, ".objc_sel_types");
auto selStruct = selectors.beginStruct(selStructTy);
selStruct.add(selName);
selStruct.add(selectorTypeEncoding);
selStruct.finishAndAddTo(selectors);
// Store the selector alias for later replacement
selectorAliases.push_back(sel.second);
}
}
// Remember the number of entries in the selector table.
selectorCount = selectors.size();
// NULL-terminate the selector list. This should not actually be required,
// because the selector list has a length field. Unfortunately, the GCC
// runtime decides to ignore the length field and expects a NULL terminator,
// and GCC cooperates with this by always setting the length to 0.
auto selStruct = selectors.beginStruct(selStructTy);
selStruct.add(NULLPtr);
selStruct.add(NULLPtr);
selStruct.finishAndAddTo(selectors);
return selectors.finishAndCreateGlobal(".objc_selector_list",
CGM.getPointerAlign());
}();
// Now that all of the static selectors exist, create pointers to them.
for (unsigned i = 0; i < selectorCount; ++i) {
llvm::Constant *idxs[] = {
Zeros[0],
llvm::ConstantInt::get(Int32Ty, i)
};
// FIXME: We're generating redundant loads and stores here!
llvm::Constant *selPtr = llvm::ConstantExpr::getGetElementPtr(
selectorList->getValueType(), selectorList, idxs);
// If selectors are defined as an opaque type, cast the pointer to this
// type.
selPtr = llvm::ConstantExpr::getBitCast(selPtr, SelectorTy);
selectorAliases[i]->replaceAllUsesWith(selPtr);
selectorAliases[i]->eraseFromParent();
}
llvm::GlobalVariable *symtab = [&] {
ConstantInitBuilder builder(CGM);
auto symtab = builder.beginStruct();
// Number of static selectors
symtab.addInt(LongTy, selectorCount);
symtab.addBitCast(selectorList, selStructPtrTy);
// Number of classes defined.
symtab.addInt(CGM.Int16Ty, Classes.size());
// Number of categories defined
symtab.addInt(CGM.Int16Ty, Categories.size());
// Create an array of classes, then categories, then static object instances
auto classList = symtab.beginArray(PtrToInt8Ty);
classList.addAll(Classes);
classList.addAll(Categories);
// NULL-terminated list of static object instances (mainly constant strings)
classList.add(statics);
classList.add(NULLPtr);
classList.finishAndAddTo(symtab);
// Construct the symbol table.
return symtab.finishAndCreateGlobal("", CGM.getPointerAlign());
}();
// The symbol table is contained in a module which has some version-checking
// constants
llvm::Constant *module = [&] {
llvm::Type *moduleEltTys[] = {
LongTy, LongTy, PtrToInt8Ty, symtab->getType(), IntTy
};
llvm::StructType *moduleTy =
llvm::StructType::get(CGM.getLLVMContext(),
makeArrayRef(moduleEltTys).drop_back(unsigned(RuntimeVersion < 10)));
ConstantInitBuilder builder(CGM);
auto module = builder.beginStruct(moduleTy);
// Runtime version, used for ABI compatibility checking.
module.addInt(LongTy, RuntimeVersion);
// sizeof(ModuleTy)
module.addInt(LongTy, CGM.getDataLayout().getTypeStoreSize(moduleTy));
// The path to the source file where this module was declared
SourceManager &SM = CGM.getContext().getSourceManager();
const FileEntry *mainFile = SM.getFileEntryForID(SM.getMainFileID());
std::string path =
(Twine(mainFile->getDir()->getName()) + "/" + mainFile->getName()).str();
module.add(MakeConstantString(path, ".objc_source_file_name"));
module.add(symtab);
if (RuntimeVersion >= 10) {
switch (CGM.getLangOpts().getGC()) {
case LangOptions::GCOnly:
module.addInt(IntTy, 2);
break;
case LangOptions::NonGC:
if (CGM.getLangOpts().ObjCAutoRefCount)
module.addInt(IntTy, 1);
else
module.addInt(IntTy, 0);
break;
case LangOptions::HybridGC:
module.addInt(IntTy, 1);
break;
}
}
return module.finishAndCreateGlobal("", CGM.getPointerAlign());
}();
// Create the load function calling the runtime entry point with the module
// structure
llvm::Function * LoadFunction = llvm::Function::Create(
llvm::FunctionType::get(llvm::Type::getVoidTy(VMContext), false),
llvm::GlobalValue::InternalLinkage, ".objc_load_function",
&TheModule);
llvm::BasicBlock *EntryBB =
llvm::BasicBlock::Create(VMContext, "entry", LoadFunction);
CGBuilderTy Builder(CGM, VMContext);
Builder.SetInsertPoint(EntryBB);
llvm::FunctionType *FT =
llvm::FunctionType::get(Builder.getVoidTy(), module->getType(), true);
llvm::Value *Register = CGM.CreateRuntimeFunction(FT, "__objc_exec_class");
Builder.CreateCall(Register, module);
if (!ClassAliases.empty()) {
llvm::Type *ArgTypes[2] = {PtrTy, PtrToInt8Ty};
llvm::FunctionType *RegisterAliasTy =
llvm::FunctionType::get(Builder.getVoidTy(),
ArgTypes, false);
llvm::Function *RegisterAlias = llvm::Function::Create(
RegisterAliasTy,
llvm::GlobalValue::ExternalWeakLinkage, "class_registerAlias_np",
&TheModule);
llvm::BasicBlock *AliasBB =
llvm::BasicBlock::Create(VMContext, "alias", LoadFunction);
llvm::BasicBlock *NoAliasBB =
llvm::BasicBlock::Create(VMContext, "no_alias", LoadFunction);
// Branch based on whether the runtime provided class_registerAlias_np()
llvm::Value *HasRegisterAlias = Builder.CreateICmpNE(RegisterAlias,
llvm::Constant::getNullValue(RegisterAlias->getType()));
Builder.CreateCondBr(HasRegisterAlias, AliasBB, NoAliasBB);
// The true branch (has alias registration function):
Builder.SetInsertPoint(AliasBB);
// Emit alias registration calls:
for (std::vector<ClassAliasPair>::iterator iter = ClassAliases.begin();
iter != ClassAliases.end(); ++iter) {
llvm::Constant *TheClass =
TheModule.getGlobalVariable("_OBJC_CLASS_" + iter->first, true);
if (TheClass) {
TheClass = llvm::ConstantExpr::getBitCast(TheClass, PtrTy);
Builder.CreateCall(RegisterAlias,
{TheClass, MakeConstantString(iter->second)});
}
}
// Jump to end:
Builder.CreateBr(NoAliasBB);
// Missing alias registration function, just return from the function:
Builder.SetInsertPoint(NoAliasBB);
}
Builder.CreateRetVoid();
return LoadFunction;
}
llvm::Function *CGObjCGNU::GenerateMethod(const ObjCMethodDecl *OMD,
const ObjCContainerDecl *CD) {
const ObjCCategoryImplDecl *OCD =
dyn_cast<ObjCCategoryImplDecl>(OMD->getDeclContext());
StringRef CategoryName = OCD ? OCD->getName() : "";
StringRef ClassName = CD->getName();
Selector MethodName = OMD->getSelector();
bool isClassMethod = !OMD->isInstanceMethod();
CodeGenTypes &Types = CGM.getTypes();
llvm::FunctionType *MethodTy =
Types.GetFunctionType(Types.arrangeObjCMethodDeclaration(OMD));
std::string FunctionName = SymbolNameForMethod(ClassName, CategoryName,
MethodName, isClassMethod);
llvm::Function *Method
= llvm::Function::Create(MethodTy,
llvm::GlobalValue::InternalLinkage,
FunctionName,
&TheModule);
return Method;
}
llvm::Constant *CGObjCGNU::GetPropertyGetFunction() {
return GetPropertyFn;
}
llvm::Constant *CGObjCGNU::GetPropertySetFunction() {
return SetPropertyFn;
}
llvm::Constant *CGObjCGNU::GetOptimizedPropertySetFunction(bool atomic,
bool copy) {
return nullptr;
}
llvm::Constant *CGObjCGNU::GetGetStructFunction() {
return GetStructPropertyFn;
}
llvm::Constant *CGObjCGNU::GetSetStructFunction() {
return SetStructPropertyFn;
}
llvm::Constant *CGObjCGNU::GetCppAtomicObjectGetFunction() {
return nullptr;
}
llvm::Constant *CGObjCGNU::GetCppAtomicObjectSetFunction() {
return nullptr;
}
llvm::Constant *CGObjCGNU::EnumerationMutationFunction() {
return EnumerationMutationFn;
}
void CGObjCGNU::EmitSynchronizedStmt(CodeGenFunction &CGF,
const ObjCAtSynchronizedStmt &S) {
EmitAtSynchronizedStmt(CGF, S, SyncEnterFn, SyncExitFn);
}
void CGObjCGNU::EmitTryStmt(CodeGenFunction &CGF,
const ObjCAtTryStmt &S) {
// Unlike the Apple non-fragile runtimes, which also uses
// unwind-based zero cost exceptions, the GNU Objective C runtime's
// EH support isn't a veneer over C++ EH. Instead, exception
// objects are created by objc_exception_throw and destroyed by
// the personality function; this avoids the need for bracketing
// catch handlers with calls to __blah_begin_catch/__blah_end_catch
// (or even _Unwind_DeleteException), but probably doesn't
// interoperate very well with foreign exceptions.
//
// In Objective-C++ mode, we actually emit something equivalent to the C++
// exception handler.
EmitTryCatchStmt(CGF, S, EnterCatchFn, ExitCatchFn, ExceptionReThrowFn);
}
void CGObjCGNU::EmitThrowStmt(CodeGenFunction &CGF,
const ObjCAtThrowStmt &S,
bool ClearInsertionPoint) {
llvm::Value *ExceptionAsObject;
bool isRethrow = false;
if (const Expr *ThrowExpr = S.getThrowExpr()) {
llvm::Value *Exception = CGF.EmitObjCThrowOperand(ThrowExpr);
ExceptionAsObject = Exception;
} else {
assert((!CGF.ObjCEHValueStack.empty() && CGF.ObjCEHValueStack.back()) &&
"Unexpected rethrow outside @catch block.");
ExceptionAsObject = CGF.ObjCEHValueStack.back();
isRethrow = true;
}
if (isRethrow && usesSEHExceptions) {
// For SEH, ExceptionAsObject may be undef, because the catch handler is
// not passed it for catchalls and so it is not visible to the catch
// funclet. The real thrown object will still be live on the stack at this
// point and will be rethrown. If we are explicitly rethrowing the object
// that was passed into the `@catch` block, then this code path is not
// reached and we will instead call `objc_exception_throw` with an explicit
// argument.
CGF.EmitRuntimeCallOrInvoke(ExceptionReThrowFn).setDoesNotReturn();
}
else {
ExceptionAsObject = CGF.Builder.CreateBitCast(ExceptionAsObject, IdTy);
llvm::CallSite Throw =
CGF.EmitRuntimeCallOrInvoke(ExceptionThrowFn, ExceptionAsObject);
Throw.setDoesNotReturn();
}
CGF.Builder.CreateUnreachable();
if (ClearInsertionPoint)
CGF.Builder.ClearInsertionPoint();
}
llvm::Value * CGObjCGNU::EmitObjCWeakRead(CodeGenFunction &CGF,
Address AddrWeakObj) {
CGBuilderTy &B = CGF.Builder;
AddrWeakObj = EnforceType(B, AddrWeakObj, PtrToIdTy);
return B.CreateCall(WeakReadFn.getType(), WeakReadFn,
AddrWeakObj.getPointer());
}
void CGObjCGNU::EmitObjCWeakAssign(CodeGenFunction &CGF,
llvm::Value *src, Address dst) {
CGBuilderTy &B = CGF.Builder;
src = EnforceType(B, src, IdTy);
dst = EnforceType(B, dst, PtrToIdTy);
B.CreateCall(WeakAssignFn.getType(), WeakAssignFn,
{src, dst.getPointer()});
}
void CGObjCGNU::EmitObjCGlobalAssign(CodeGenFunction &CGF,
llvm::Value *src, Address dst,
bool threadlocal) {
CGBuilderTy &B = CGF.Builder;
src = EnforceType(B, src, IdTy);
dst = EnforceType(B, dst, PtrToIdTy);
// FIXME. Add threadloca assign API
assert(!threadlocal && "EmitObjCGlobalAssign - Threal Local API NYI");
B.CreateCall(GlobalAssignFn.getType(), GlobalAssignFn,
{src, dst.getPointer()});
}
void CGObjCGNU::EmitObjCIvarAssign(CodeGenFunction &CGF,
llvm::Value *src, Address dst,
llvm::Value *ivarOffset) {
CGBuilderTy &B = CGF.Builder;
src = EnforceType(B, src, IdTy);
dst = EnforceType(B, dst, IdTy);
B.CreateCall(IvarAssignFn.getType(), IvarAssignFn,
{src, dst.getPointer(), ivarOffset});
}
void CGObjCGNU::EmitObjCStrongCastAssign(CodeGenFunction &CGF,
llvm::Value *src, Address dst) {
CGBuilderTy &B = CGF.Builder;
src = EnforceType(B, src, IdTy);
dst = EnforceType(B, dst, PtrToIdTy);
B.CreateCall(StrongCastAssignFn.getType(), StrongCastAssignFn,
{src, dst.getPointer()});
}
void CGObjCGNU::EmitGCMemmoveCollectable(CodeGenFunction &CGF,
Address DestPtr,
Address SrcPtr,
llvm::Value *Size) {
CGBuilderTy &B = CGF.Builder;
DestPtr = EnforceType(B, DestPtr, PtrTy);
SrcPtr = EnforceType(B, SrcPtr, PtrTy);
B.CreateCall(MemMoveFn.getType(), MemMoveFn,
{DestPtr.getPointer(), SrcPtr.getPointer(), Size});
}
llvm::GlobalVariable *CGObjCGNU::ObjCIvarOffsetVariable(
const ObjCInterfaceDecl *ID,
const ObjCIvarDecl *Ivar) {
const std::string Name = GetIVarOffsetVariableName(ID, Ivar);
// Emit the variable and initialize it with what we think the correct value
// is. This allows code compiled with non-fragile ivars to work correctly
// when linked against code which isn't (most of the time).
llvm::GlobalVariable *IvarOffsetPointer = TheModule.getNamedGlobal(Name);
if (!IvarOffsetPointer)
IvarOffsetPointer = new llvm::GlobalVariable(TheModule,
llvm::Type::getInt32PtrTy(VMContext), false,
llvm::GlobalValue::ExternalLinkage, nullptr, Name);
return IvarOffsetPointer;
}
LValue CGObjCGNU::EmitObjCValueForIvar(CodeGenFunction &CGF,
QualType ObjectTy,
llvm::Value *BaseValue,
const ObjCIvarDecl *Ivar,
unsigned CVRQualifiers) {
const ObjCInterfaceDecl *ID =
ObjectTy->getAs<ObjCObjectType>()->getInterface();
return EmitValueForIvarAtOffset(CGF, ID, BaseValue, Ivar, CVRQualifiers,
EmitIvarOffset(CGF, ID, Ivar));
}
static const ObjCInterfaceDecl *FindIvarInterface(ASTContext &Context,
const ObjCInterfaceDecl *OID,
const ObjCIvarDecl *OIVD) {
for (const ObjCIvarDecl *next = OID->all_declared_ivar_begin(); next;
next = next->getNextIvar()) {
if (OIVD == next)
return OID;
}
// Otherwise check in the super class.
if (const ObjCInterfaceDecl *Super = OID->getSuperClass())
return FindIvarInterface(Context, Super, OIVD);
return nullptr;
}
llvm::Value *CGObjCGNU::EmitIvarOffset(CodeGenFunction &CGF,
const ObjCInterfaceDecl *Interface,
const ObjCIvarDecl *Ivar) {
if (CGM.getLangOpts().ObjCRuntime.isNonFragile()) {
Interface = FindIvarInterface(CGM.getContext(), Interface, Ivar);
// The MSVC linker cannot have a single global defined as LinkOnceAnyLinkage
// and ExternalLinkage, so create a reference to the ivar global and rely on
// the definition being created as part of GenerateClass.
if (RuntimeVersion < 10 ||
CGF.CGM.getTarget().getTriple().isKnownWindowsMSVCEnvironment())
return CGF.Builder.CreateZExtOrBitCast(
CGF.Builder.CreateAlignedLoad(
Int32Ty, CGF.Builder.CreateAlignedLoad(
ObjCIvarOffsetVariable(Interface, Ivar),
CGF.getPointerAlign(), "ivar"),
CharUnits::fromQuantity(4)),
PtrDiffTy);
std::string name = "__objc_ivar_offset_value_" +
Interface->getNameAsString() +"." + Ivar->getNameAsString();
CharUnits Align = CGM.getIntAlign();
llvm::Value *Offset = TheModule.getGlobalVariable(name);
if (!Offset) {
auto GV = new llvm::GlobalVariable(TheModule, IntTy,
false, llvm::GlobalValue::LinkOnceAnyLinkage,
llvm::Constant::getNullValue(IntTy), name);
GV->setAlignment(Align.getQuantity());
Offset = GV;
}
Offset = CGF.Builder.CreateAlignedLoad(Offset, Align);
if (Offset->getType() != PtrDiffTy)
Offset = CGF.Builder.CreateZExtOrBitCast(Offset, PtrDiffTy);
return Offset;
}
uint64_t Offset = ComputeIvarBaseOffset(CGF.CGM, Interface, Ivar);
return llvm::ConstantInt::get(PtrDiffTy, Offset, /*isSigned*/true);
}
CGObjCRuntime *
clang::CodeGen::CreateGNUObjCRuntime(CodeGenModule &CGM) {
auto Runtime = CGM.getLangOpts().ObjCRuntime;
switch (Runtime.getKind()) {
case ObjCRuntime::GNUstep:
if (Runtime.getVersion() >= VersionTuple(2, 0))
return new CGObjCGNUstep2(CGM);
return new CGObjCGNUstep(CGM);
case ObjCRuntime::GCC:
return new CGObjCGCC(CGM);
case ObjCRuntime::ObjFW:
return new CGObjCObjFW(CGM);
case ObjCRuntime::FragileMacOSX:
case ObjCRuntime::MacOSX:
case ObjCRuntime::iOS:
case ObjCRuntime::WatchOS:
llvm_unreachable("these runtimes are not GNU runtimes");
}
llvm_unreachable("bad runtime");
}