llvm/clang/lib/CodeGen/CGObjCMac.cpp

//===------- CGObjCMac.cpp - Interface to Apple Objective-C Runtime -------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This provides Objective-C code generation targeting the Apple runtime.
//
//===----------------------------------------------------------------------===//

#include "CGBlocks.h"
#include "CGCleanup.h"
#include "CGObjCRuntime.h"
#include "CGRecordLayout.h"
#include "CodeGenFunction.h"
#include "CodeGenModule.h"
#include "clang/AST/ASTContext.h"
#include "clang/AST/Attr.h"
#include "clang/AST/Decl.h"
#include "clang/AST/DeclObjC.h"
#include "clang/AST/Mangle.h"
#include "clang/AST/RecordLayout.h"
#include "clang/AST/StmtObjC.h"
#include "clang/Basic/CodeGenOptions.h"
#include "clang/Basic/LangOptions.h"
#include "clang/CodeGen/CGFunctionInfo.h"
#include "clang/CodeGen/ConstantInitBuilder.h"
#include "llvm/ADT/CachedHashString.h"
#include "llvm/ADT/DenseSet.h"
#include "llvm/ADT/SetVector.h"
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/ADT/UniqueVector.h"
#include "llvm/IR/DataLayout.h"
#include "llvm/IR/InlineAsm.h"
#include "llvm/IR/IntrinsicInst.h"
#include "llvm/IR/LLVMContext.h"
#include "llvm/IR/Module.h"
#include "llvm/Support/ScopedPrinter.h"
#include "llvm/Support/raw_ostream.h"
#include <cstdio>

usingnamespaceclang;
usingnamespaceCodeGen;

namespace {

// FIXME: We should find a nicer way to make the labels for metadata, string
// concatenation is lame.

class ObjCCommonTypesHelper { … };

/// ObjCTypesHelper - Helper class that encapsulates lazy
/// construction of varies types used during ObjC generation.
class ObjCTypesHelper : public ObjCCommonTypesHelper { … };

/// ObjCNonFragileABITypesHelper - will have all types needed by objective-c's
/// modern abi
class ObjCNonFragileABITypesHelper : public ObjCCommonTypesHelper { … };

enum class ObjCLabelType { … };

class CGObjCCommonMac : public CodeGen::CGObjCRuntime { … };

namespace {

enum class MethodListType { … };

/// A convenience class for splitting the methods of a protocol into
/// the four interesting groups.
class ProtocolMethodLists { … };

} // end anonymous namespace

class CGObjCMac : public CGObjCCommonMac { … };

class CGObjCNonFragileABIMac : public CGObjCCommonMac { … };

/// A helper class for performing the null-initialization of a return
/// value.
struct NullReturnState { … };

} // end anonymous namespace

/* *** Helper Functions *** */

/// getConstantGEP() - Help routine to construct simple GEPs.
static llvm::Constant *getConstantGEP(llvm::LLVMContext &VMContext,
                                      llvm::GlobalVariable *C, unsigned idx0,
                                      unsigned idx1) { … }

/// hasObjCExceptionAttribute - Return true if this class or any super
/// class has the __objc_exception__ attribute.
static bool hasObjCExceptionAttribute(ASTContext &Context,
                                      const ObjCInterfaceDecl *OID) { … }

static llvm::GlobalValue::LinkageTypes
getLinkageTypeForObjCMetadata(CodeGenModule &CGM, StringRef Section) { … }

/// A helper function to create an internal or private global variable.
static llvm::GlobalVariable *
finishAndCreateGlobal(ConstantInitBuilder::StructBuilder &Builder,
                     const llvm::Twine &Name, CodeGenModule &CGM) { … }

/* *** CGObjCMac Public Interface *** */

CGObjCMac::CGObjCMac(CodeGen::CodeGenModule &cgm) : … { … }

/// GetClass - Return a reference to the class for the given interface
/// decl.
llvm::Value *CGObjCMac::GetClass(CodeGenFunction &CGF,
                                 const ObjCInterfaceDecl *ID) { … }

/// GetSelector - Return the pointer to the unique'd string for this selector.
llvm::Value *CGObjCMac::GetSelector(CodeGenFunction &CGF, Selector Sel) { … }
Address CGObjCMac::GetAddrOfSelector(CodeGenFunction &CGF, Selector Sel) { … }
llvm::Value *CGObjCMac::GetSelector(CodeGenFunction &CGF, const ObjCMethodDecl
                                    *Method) { … }

llvm::Constant *CGObjCMac::GetEHType(QualType T) { … }

/// Generate a constant CFString object.
/*
  struct __builtin_CFString {
  const int *isa; // point to __CFConstantStringClassReference
  int flags;
  const char *str;
  long length;
  };
*/

/// or Generate a constant NSString object.
/*
   struct __builtin_NSString {
     const int *isa; // point to __NSConstantStringClassReference
     const char *str;
     unsigned int length;
   };
*/

ConstantAddress
CGObjCCommonMac::GenerateConstantString(const StringLiteral *SL) { … }

static llvm::StringMapEntry<llvm::GlobalVariable *> &
GetConstantStringEntry(llvm::StringMap<llvm::GlobalVariable *> &Map,
                       const StringLiteral *Literal, unsigned &StringLength) { … }

llvm::Constant *CGObjCMac::getNSConstantStringClassRef() { … }

llvm::Constant *CGObjCNonFragileABIMac::getNSConstantStringClassRef() { … }

ConstantAddress
CGObjCCommonMac::GenerateConstantNSString(const StringLiteral *Literal) { … }

enum { … };

/// 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.
CodeGen::RValue
CGObjCMac::GenerateMessageSendSuper(CodeGen::CodeGenFunction &CGF,
                                    ReturnValueSlot Return,
                                    QualType ResultType,
                                    Selector Sel,
                                    const ObjCInterfaceDecl *Class,
                                    bool isCategoryImpl,
                                    llvm::Value *Receiver,
                                    bool IsClassMessage,
                                    const CodeGen::CallArgList &CallArgs,
                                    const ObjCMethodDecl *Method) { … }

/// Generate code for a message send expression.
CodeGen::RValue CGObjCMac::GenerateMessageSend(CodeGen::CodeGenFunction &CGF,
                                               ReturnValueSlot Return,
                                               QualType ResultType,
                                               Selector Sel,
                                               llvm::Value *Receiver,
                                               const CallArgList &CallArgs,
                                               const ObjCInterfaceDecl *Class,
                                               const ObjCMethodDecl *Method) { … }

CodeGen::RValue
CGObjCCommonMac::EmitMessageSend(CodeGen::CodeGenFunction &CGF,
                                 ReturnValueSlot Return,
                                 QualType ResultType,
                                 Selector Sel,
                                 llvm::Value *Arg0,
                                 QualType Arg0Ty,
                                 bool IsSuper,
                                 const CallArgList &CallArgs,
                                 const ObjCMethodDecl *Method,
                                 const ObjCInterfaceDecl *ClassReceiver,
                                 const ObjCCommonTypesHelper &ObjCTypes) { … }

static Qualifiers::GC GetGCAttrTypeForType(ASTContext &Ctx, QualType FQT,
                                           bool pointee = false) { … }

namespace {
  struct IvarInfo { … };

  /// A helper class for building GC layout strings.
  class IvarLayoutBuilder { … };
} // end anonymous namespace

llvm::Constant *CGObjCCommonMac::BuildGCBlockLayout(CodeGenModule &CGM,
                                                const CGBlockInfo &blockInfo) { … }

void IvarLayoutBuilder::visitBlock(const CGBlockInfo &blockInfo) { … }

/// getBlockCaptureLifetime - This routine returns life time of the captured
/// block variable for the purpose of block layout meta-data generation. FQT is
/// the type of the variable captured in the block.
Qualifiers::ObjCLifetime CGObjCCommonMac::getBlockCaptureLifetime(QualType FQT,
                                                                  bool ByrefLayout) { … }

void CGObjCCommonMac::UpdateRunSkipBlockVars(bool IsByref,
                                             Qualifiers::ObjCLifetime LifeTime,
                                             CharUnits FieldOffset,
                                             CharUnits FieldSize) { … }

void CGObjCCommonMac::BuildRCRecordLayout(const llvm::StructLayout *RecLayout,
                                          const RecordDecl *RD,
                                          ArrayRef<const FieldDecl*> RecFields,
                                          CharUnits BytePos, bool &HasUnion,
                                          bool ByrefLayout) { … }

void CGObjCCommonMac::BuildRCBlockVarRecordLayout(const RecordType *RT,
                                                  CharUnits BytePos,
                                                  bool &HasUnion,
                                                  bool ByrefLayout) { … }

/// InlineLayoutInstruction - This routine produce an inline instruction for the
/// block variable layout if it can. If not, it returns 0. Rules are as follow:
/// If ((uintptr_t) layout) < (1 << 12), the layout is inline. In the 64bit world,
/// an inline layout of value 0x0000000000000xyz is interpreted as follows:
/// x captured object pointers of BLOCK_LAYOUT_STRONG. Followed by
/// y captured object of BLOCK_LAYOUT_BYREF. Followed by
/// z captured object of BLOCK_LAYOUT_WEAK. If any of the above is missing, zero
/// replaces it. For example, 0x00000x00 means x BLOCK_LAYOUT_STRONG and no
/// BLOCK_LAYOUT_BYREF and no BLOCK_LAYOUT_WEAK objects are captured.
uint64_t CGObjCCommonMac::InlineLayoutInstruction(
                                    SmallVectorImpl<unsigned char> &Layout) { … }

llvm::Constant *CGObjCCommonMac::getBitmapBlockLayout(bool ComputeByrefLayout) { … }

static std::string getBlockLayoutInfoString(
    const SmallVectorImpl<CGObjCCommonMac::RUN_SKIP> &RunSkipBlockVars,
    bool HasCopyDisposeHelpers) { … }

void CGObjCCommonMac::fillRunSkipBlockVars(CodeGenModule &CGM,
                                           const CGBlockInfo &blockInfo) { … }

llvm::Constant *
CGObjCCommonMac::BuildRCBlockLayout(CodeGenModule &CGM,
                                    const CGBlockInfo &blockInfo) { … }

std::string CGObjCCommonMac::getRCBlockLayoutStr(CodeGenModule &CGM,
                                                 const CGBlockInfo &blockInfo) { … }

llvm::Constant *CGObjCCommonMac::BuildByrefLayout(CodeGen::CodeGenModule &CGM,
                                                  QualType T) { … }

llvm::Value *CGObjCMac::GenerateProtocolRef(CodeGenFunction &CGF,
                                            const ObjCProtocolDecl *PD) { … }

void CGObjCCommonMac::GenerateProtocol(const ObjCProtocolDecl *PD) { … }

llvm::Constant *CGObjCCommonMac::GetProtocolRef(const ObjCProtocolDecl *PD) { … }

llvm::Value *CGObjCCommonMac::EmitClassRefViaRuntime(
               CodeGenFunction &CGF,
               const ObjCInterfaceDecl *ID,
               ObjCCommonTypesHelper &ObjCTypes) { … }

/*
// Objective-C 1.0 extensions
struct _objc_protocol {
struct _objc_protocol_extension *isa;
char *protocol_name;
struct _objc_protocol_list *protocol_list;
struct _objc__method_prototype_list *instance_methods;
struct _objc__method_prototype_list *class_methods
};

See EmitProtocolExtension().
*/
llvm::Constant *CGObjCMac::GetOrEmitProtocol(const ObjCProtocolDecl *PD) { … }

llvm::Constant *CGObjCMac::GetOrEmitProtocolRef(const ObjCProtocolDecl *PD) { … }

/*
  struct _objc_protocol_extension {
  uint32_t size;
  struct objc_method_description_list *optional_instance_methods;
  struct objc_method_description_list *optional_class_methods;
  struct objc_property_list *instance_properties;
  const char ** extendedMethodTypes;
  struct objc_property_list *class_properties;
  };
*/
llvm::Constant *
CGObjCMac::EmitProtocolExtension(const ObjCProtocolDecl *PD,
                                 const ProtocolMethodLists &methodLists) { … }

/*
  struct objc_protocol_list {
    struct objc_protocol_list *next;
    long count;
    Protocol *list[];
  };
*/
llvm::Constant *
CGObjCMac::EmitProtocolList(Twine name,
                            ObjCProtocolDecl::protocol_iterator begin,
                            ObjCProtocolDecl::protocol_iterator end) { … }

static void
PushProtocolProperties(llvm::SmallPtrSet<const IdentifierInfo*,16> &PropertySet,
                       SmallVectorImpl<const ObjCPropertyDecl *> &Properties,
                       const ObjCProtocolDecl *Proto,
                       bool IsClassProperty) { … }

/*
  struct _objc_property {
    const char * const name;
    const char * const attributes;
  };

  struct _objc_property_list {
    uint32_t entsize; // sizeof (struct _objc_property)
    uint32_t prop_count;
    struct _objc_property[prop_count];
  };
*/
llvm::Constant *CGObjCCommonMac::EmitPropertyList(Twine Name,
                                       const Decl *Container,
                                       const ObjCContainerDecl *OCD,
                                       const ObjCCommonTypesHelper &ObjCTypes,
                                       bool IsClassProperty) { … }

llvm::Constant *
CGObjCCommonMac::EmitProtocolMethodTypes(Twine Name,
                                         ArrayRef<llvm::Constant*> MethodTypes,
                                         const ObjCCommonTypesHelper &ObjCTypes) { … }

/*
  struct _objc_category {
  char *category_name;
  char *class_name;
  struct _objc_method_list *instance_methods;
  struct _objc_method_list *class_methods;
  struct _objc_protocol_list *protocols;
  uint32_t size; // sizeof(struct _objc_category)
  struct _objc_property_list *instance_properties;
  struct _objc_property_list *class_properties;
  };
*/
void CGObjCMac::GenerateCategory(const ObjCCategoryImplDecl *OCD) { … }

enum FragileClassFlags { … };

enum NonFragileClassFlags { … };

static bool hasWeakMember(QualType type) { … }

/// For compatibility, we only want to set the "HasMRCWeakIvars" flag
/// (and actually fill in a layout string) if we really do have any
/// __weak ivars.
static bool hasMRCWeakIvars(CodeGenModule &CGM,
                            const ObjCImplementationDecl *ID) { … }

/*
  struct _objc_class {
  Class isa;
  Class super_class;
  const char *name;
  long version;
  long info;
  long instance_size;
  struct _objc_ivar_list *ivars;
  struct _objc_method_list *methods;
  struct _objc_cache *cache;
  struct _objc_protocol_list *protocols;
  // Objective-C 1.0 extensions (<rdr://4585769>)
  const char *ivar_layout;
  struct _objc_class_ext *ext;
  };

  See EmitClassExtension();
*/
void CGObjCMac::GenerateClass(const ObjCImplementationDecl *ID) { … }

llvm::Constant *CGObjCMac::EmitMetaClass(const ObjCImplementationDecl *ID,
                                         llvm::Constant *Protocols,
                                ArrayRef<const ObjCMethodDecl*> Methods) { … }

llvm::Constant *CGObjCMac::EmitMetaClassRef(const ObjCInterfaceDecl *ID) { … }

llvm::Value *CGObjCMac::EmitSuperClassRef(const ObjCInterfaceDecl *ID) { … }

/*
  Emit a "class extension", which in this specific context means extra
  data that doesn't fit in the normal fragile-ABI class structure, and
  has nothing to do with the language concept of a class extension.

  struct objc_class_ext {
  uint32_t size;
  const char *weak_ivar_layout;
  struct _objc_property_list *properties;
  };
*/
llvm::Constant *
CGObjCMac::EmitClassExtension(const ObjCImplementationDecl *ID,
                              CharUnits InstanceSize, bool hasMRCWeakIvars,
                              bool isMetaclass) { … }

/*
  struct objc_ivar {
    char *ivar_name;
    char *ivar_type;
    int ivar_offset;
  };

  struct objc_ivar_list {
    int ivar_count;
    struct objc_ivar list[count];
  };
*/
llvm::Constant *CGObjCMac::EmitIvarList(const ObjCImplementationDecl *ID,
                                        bool ForClass) { … }

/// Build a struct objc_method_description constant for the given method.
///
/// struct objc_method_description {
///   SEL method_name;
///   char *method_types;
/// };
void CGObjCMac::emitMethodDescriptionConstant(ConstantArrayBuilder &builder,
                                              const ObjCMethodDecl *MD) { … }

/// Build a struct objc_method constant for the given method.
///
/// struct objc_method {
///   SEL method_name;
///   char *method_types;
///   void *method;
/// };
void CGObjCMac::emitMethodConstant(ConstantArrayBuilder &builder,
                                   const ObjCMethodDecl *MD) { … }

/// Build a struct objc_method_list or struct objc_method_description_list,
/// as appropriate.
///
/// struct objc_method_list {
///   struct objc_method_list *obsolete;
///   int count;
///   struct objc_method methods_list[count];
/// };
///
/// struct objc_method_description_list {
///   int count;
///   struct objc_method_description list[count];
/// };
llvm::Constant *CGObjCMac::emitMethodList(Twine name, MethodListType MLT,
                                 ArrayRef<const ObjCMethodDecl *> methods) { … }

llvm::Function *CGObjCCommonMac::GenerateMethod(const ObjCMethodDecl *OMD,
                                                const ObjCContainerDecl *CD) { … }

llvm::Function *
CGObjCCommonMac::GenerateDirectMethod(const ObjCMethodDecl *OMD,
                                      const ObjCContainerDecl *CD) { … }

void CGObjCCommonMac::GenerateDirectMethodPrologue(
    CodeGenFunction &CGF, llvm::Function *Fn, const ObjCMethodDecl *OMD,
    const ObjCContainerDecl *CD) { … }

llvm::GlobalVariable *CGObjCCommonMac::CreateMetadataVar(Twine Name,
                                               ConstantStructBuilder &Init,
                                                         StringRef Section,
                                                         CharUnits Align,
                                                         bool AddToUsed) { … }

llvm::GlobalVariable *CGObjCCommonMac::CreateMetadataVar(Twine Name,
                                                         llvm::Constant *Init,
                                                         StringRef Section,
                                                         CharUnits Align,
                                                         bool AddToUsed) { … }

llvm::GlobalVariable *
CGObjCCommonMac::CreateCStringLiteral(StringRef Name, ObjCLabelType Type,
                                      bool ForceNonFragileABI,
                                      bool NullTerminate) { … }

llvm::Function *CGObjCMac::ModuleInitFunction() { … }

llvm::FunctionCallee CGObjCMac::GetPropertyGetFunction() { … }

llvm::FunctionCallee CGObjCMac::GetPropertySetFunction() { … }

llvm::FunctionCallee CGObjCMac::GetOptimizedPropertySetFunction(bool atomic,
                                                                bool copy) { … }

llvm::FunctionCallee CGObjCMac::GetGetStructFunction() { … }

llvm::FunctionCallee CGObjCMac::GetSetStructFunction() { … }

llvm::FunctionCallee CGObjCMac::GetCppAtomicObjectGetFunction() { … }

llvm::FunctionCallee CGObjCMac::GetCppAtomicObjectSetFunction() { … }

llvm::FunctionCallee CGObjCMac::EnumerationMutationFunction() { … }

void CGObjCMac::EmitTryStmt(CodeGenFunction &CGF, const ObjCAtTryStmt &S) { … }

void CGObjCMac::EmitSynchronizedStmt(CodeGenFunction &CGF,
                                     const ObjCAtSynchronizedStmt &S) { … }

namespace {
  struct PerformFragileFinally final : EHScopeStack::Cleanup { … };

  class FragileHazards { … };
} // end anonymous namespace

/// Create the fragile-ABI read and write hazards based on the current
/// state of the function, which is presumed to be immediately prior
/// to a @try block.  These hazards are used to maintain correct
/// semantics in the face of optimization and the fragile ABI's
/// cavalier use of setjmp/longjmp.
FragileHazards::FragileHazards(CodeGenFunction &CGF) : … { … }

/// Emit a write hazard at the current location.
void FragileHazards::emitWriteHazard() { … }

void FragileHazards::emitReadHazard(CGBuilderTy &Builder) { … }

/// Emit read hazards in all the protected blocks, i.e. all the blocks
/// which have been inserted since the beginning of the try.
void FragileHazards::emitHazardsInNewBlocks() { … }

static void addIfPresent(llvm::DenseSet<llvm::Value*> &S, Address V) { … }

void FragileHazards::collectLocals() { … }

llvm::FunctionType *FragileHazards::GetAsmFnType() { … }

/*

  Objective-C setjmp-longjmp (sjlj) Exception Handling
  --

  A catch buffer is a setjmp buffer plus:
    - a pointer to the exception that was caught
    - a pointer to the previous exception data buffer
    - two pointers of reserved storage
  Therefore catch buffers form a stack, with a pointer to the top
  of the stack kept in thread-local storage.

  objc_exception_try_enter pushes a catch buffer onto the EH stack.
  objc_exception_try_exit pops the given catch buffer, which is
    required to be the top of the EH stack.
  objc_exception_throw pops the top of the EH stack, writes the
    thrown exception into the appropriate field, and longjmps
    to the setjmp buffer.  It crashes the process (with a printf
    and an abort()) if there are no catch buffers on the stack.
  objc_exception_extract just reads the exception pointer out of the
    catch buffer.

  There's no reason an implementation couldn't use a light-weight
  setjmp here --- something like __builtin_setjmp, but API-compatible
  with the heavyweight setjmp.  This will be more important if we ever
  want to implement correct ObjC/C++ exception interactions for the
  fragile ABI.

  Note that for this use of setjmp/longjmp to be correct in the presence of
  optimization, we use inline assembly on the set of local variables to force
  flushing locals to memory immediately before any protected calls and to
  inhibit optimizing locals across the setjmp->catch edge.

  The basic framework for a @try-catch-finally is as follows:
  {
  objc_exception_data d;
  id _rethrow = null;
  bool _call_try_exit = true;

  objc_exception_try_enter(&d);
  if (!setjmp(d.jmp_buf)) {
  ... try body ...
  } else {
  // exception path
  id _caught = objc_exception_extract(&d);

  // enter new try scope for handlers
  if (!setjmp(d.jmp_buf)) {
  ... match exception and execute catch blocks ...

  // fell off end, rethrow.
  _rethrow = _caught;
  ... jump-through-finally to finally_rethrow ...
  } else {
  // exception in catch block
  _rethrow = objc_exception_extract(&d);
  _call_try_exit = false;
  ... jump-through-finally to finally_rethrow ...
  }
  }
  ... jump-through-finally to finally_end ...

  finally:
  if (_call_try_exit)
  objc_exception_try_exit(&d);

  ... finally block ....
  ... dispatch to finally destination ...

  finally_rethrow:
  objc_exception_throw(_rethrow);

  finally_end:
  }

  This framework differs slightly from the one gcc uses, in that gcc
  uses _rethrow to determine if objc_exception_try_exit should be called
  and if the object should be rethrown. This breaks in the face of
  throwing nil and introduces unnecessary branches.

  We specialize this framework for a few particular circumstances:

  - If there are no catch blocks, then we avoid emitting the second
  exception handling context.

  - If there is a catch-all catch block (i.e. @catch(...) or @catch(id
  e)) we avoid emitting the code to rethrow an uncaught exception.

  - FIXME: If there is no @finally block we can do a few more
  simplifications.

  Rethrows and Jumps-Through-Finally
  --

  '@throw;' is supported by pushing the currently-caught exception
  onto ObjCEHStack while the @catch blocks are emitted.

  Branches through the @finally block are handled with an ordinary
  normal cleanup.  We do not register an EH cleanup; fragile-ABI ObjC
  exceptions are not compatible with C++ exceptions, and this is
  hardly the only place where this will go wrong.

  @synchronized(expr) { stmt; } is emitted as if it were:
    id synch_value = expr;
    objc_sync_enter(synch_value);
    @try { stmt; } @finally { objc_sync_exit(synch_value); }
*/

void CGObjCMac::EmitTryOrSynchronizedStmt(CodeGen::CodeGenFunction &CGF,
                                          const Stmt &S) { … }

void CGObjCMac::EmitThrowStmt(CodeGen::CodeGenFunction &CGF,
                              const ObjCAtThrowStmt &S,
                              bool ClearInsertionPoint) { … }

/// EmitObjCWeakRead - Code gen for loading value of a __weak
/// object: objc_read_weak (id *src)
///
llvm::Value * CGObjCMac::EmitObjCWeakRead(CodeGen::CodeGenFunction &CGF,
                                          Address AddrWeakObj) { … }

/// EmitObjCWeakAssign - Code gen for assigning to a __weak object.
/// objc_assign_weak (id src, id *dst)
///
void CGObjCMac::EmitObjCWeakAssign(CodeGen::CodeGenFunction &CGF,
                                   llvm::Value *src, Address dst) { … }

/// EmitObjCGlobalAssign - Code gen for assigning to a __strong object.
/// objc_assign_global (id src, id *dst)
///
void CGObjCMac::EmitObjCGlobalAssign(CodeGen::CodeGenFunction &CGF,
                                     llvm::Value *src, Address dst,
                                     bool threadlocal) { … }

/// EmitObjCIvarAssign - Code gen for assigning to a __strong object.
/// objc_assign_ivar (id src, id *dst, ptrdiff_t ivaroffset)
///
void CGObjCMac::EmitObjCIvarAssign(CodeGen::CodeGenFunction &CGF,
                                   llvm::Value *src, Address dst,
                                   llvm::Value *ivarOffset) { … }

/// EmitObjCStrongCastAssign - Code gen for assigning to a __strong cast object.
/// objc_assign_strongCast (id src, id *dst)
///
void CGObjCMac::EmitObjCStrongCastAssign(CodeGen::CodeGenFunction &CGF,
                                         llvm::Value *src, Address dst) { … }

void CGObjCMac::EmitGCMemmoveCollectable(CodeGen::CodeGenFunction &CGF,
                                         Address DestPtr, Address SrcPtr,
                                         llvm::Value *size) { … }

/// EmitObjCValueForIvar - Code Gen for ivar reference.
///
LValue CGObjCMac::EmitObjCValueForIvar(CodeGen::CodeGenFunction &CGF,
                                       QualType ObjectTy,
                                       llvm::Value *BaseValue,
                                       const ObjCIvarDecl *Ivar,
                                       unsigned CVRQualifiers) { … }

llvm::Value *CGObjCMac::EmitIvarOffset(CodeGen::CodeGenFunction &CGF,
                                       const ObjCInterfaceDecl *Interface,
                                       const ObjCIvarDecl *Ivar) { … }

/* *** Private Interface *** */

std::string CGObjCCommonMac::GetSectionName(StringRef Section,
                                            StringRef MachOAttributes) { … }

/// EmitImageInfo - Emit the image info marker used to encode some module
/// level information.
///
/// See: <rdr://4810609&4810587&4810587>
/// struct IMAGE_INFO {
///   unsigned version;
///   unsigned flags;
/// };
enum ImageInfoFlags { … };

void CGObjCCommonMac::EmitImageInfo() { … }

// struct objc_module {
//   unsigned long version;
//   unsigned long size;
//   const char *name;
//   Symtab symtab;
// };

// FIXME: Get from somewhere
static const int ModuleVersion = …;

void CGObjCMac::EmitModuleInfo() { … }

llvm::Constant *CGObjCMac::EmitModuleSymbols() { … }

llvm::Value *CGObjCMac::EmitClassRefFromId(CodeGenFunction &CGF,
                                           IdentifierInfo *II) { … }

llvm::Value *CGObjCMac::EmitClassRef(CodeGenFunction &CGF,
                                     const ObjCInterfaceDecl *ID) { … }

llvm::Value *CGObjCMac::EmitNSAutoreleasePoolClassRef(CodeGenFunction &CGF) { … }

llvm::Value *CGObjCMac::EmitSelector(CodeGenFunction &CGF, Selector Sel) { … }

ConstantAddress CGObjCMac::EmitSelectorAddr(Selector Sel) { … }

llvm::Constant *CGObjCCommonMac::GetClassName(StringRef RuntimeName) { … }

llvm::Function *CGObjCCommonMac::GetMethodDefinition(const ObjCMethodDecl *MD) { … }

/// GetIvarLayoutName - Returns a unique constant for the given
/// ivar layout bitmap.
llvm::Constant *CGObjCCommonMac::GetIvarLayoutName(IdentifierInfo *Ident,
                                       const ObjCCommonTypesHelper &ObjCTypes) { … }

void IvarLayoutBuilder::visitRecord(const RecordType *RT,
                                    CharUnits offset) { … }

template <class Iterator, class GetOffsetFn>
void IvarLayoutBuilder::visitAggregate(Iterator begin, Iterator end,
                                       CharUnits aggregateOffset,
                                       const GetOffsetFn &getOffset) { … }

/// Collect layout information for the given fields into IvarsInfo.
void IvarLayoutBuilder::visitField(const FieldDecl *field,
                                   CharUnits fieldOffset) { … }

/// buildBitmap - This routine does the horsework of taking the offsets of
/// strong/weak references and creating a bitmap.  The bitmap is also
/// returned in the given buffer, suitable for being passed to \c dump().
llvm::Constant *IvarLayoutBuilder::buildBitmap(CGObjCCommonMac &CGObjC,
                                llvm::SmallVectorImpl<unsigned char> &buffer) { … }

/// BuildIvarLayout - Builds ivar layout bitmap for the class
/// implementation for the __strong or __weak case.
/// The layout map displays which words in ivar list must be skipped
/// and which must be scanned by GC (see below). String is built of bytes.
/// Each byte is divided up in two nibbles (4-bit each). Left nibble is count
/// of words to skip and right nibble is count of words to scan. So, each
/// nibble represents up to 15 workds to skip or scan. Skipping the rest is
/// represented by a 0x00 byte which also ends the string.
/// 1. when ForStrongLayout is true, following ivars are scanned:
/// - id, Class
/// - object *
/// - __strong anything
///
/// 2. When ForStrongLayout is false, following ivars are scanned:
/// - __weak anything
///
llvm::Constant *
CGObjCCommonMac::BuildIvarLayout(const ObjCImplementationDecl *OMD,
                                 CharUnits beginOffset, CharUnits endOffset,
                                 bool ForStrongLayout, bool HasMRCWeakIvars) { … }

llvm::Constant *CGObjCCommonMac::GetMethodVarName(Selector Sel) { … }

// FIXME: Merge into a single cstring creation function.
llvm::Constant *CGObjCCommonMac::GetMethodVarName(IdentifierInfo *ID) { … }

llvm::Constant *CGObjCCommonMac::GetMethodVarType(const FieldDecl *Field) { … }

llvm::Constant *CGObjCCommonMac::GetMethodVarType(const ObjCMethodDecl *D,
                                                  bool Extended) { … }

// FIXME: Merge into a single cstring creation function.
llvm::Constant *CGObjCCommonMac::GetPropertyName(IdentifierInfo *Ident) { … }

// FIXME: Merge into a single cstring creation function.
// FIXME: This Decl should be more precise.
llvm::Constant *
CGObjCCommonMac::GetPropertyTypeString(const ObjCPropertyDecl *PD,
                                       const Decl *Container) { … }

void CGObjCMac::FinishModule() { … }

CGObjCNonFragileABIMac::CGObjCNonFragileABIMac(CodeGen::CodeGenModule &cgm)
    : … { … }

/* *** */

ObjCCommonTypesHelper::ObjCCommonTypesHelper(CodeGen::CodeGenModule &cgm)
  : … { … }

ObjCTypesHelper::ObjCTypesHelper(CodeGen::CodeGenModule &cgm)
  : … { … }

ObjCNonFragileABITypesHelper::ObjCNonFragileABITypesHelper(CodeGen::CodeGenModule &cgm)
  : … { … }

llvm::Function *CGObjCNonFragileABIMac::ModuleInitFunction() { … }

void CGObjCNonFragileABIMac::AddModuleClassList(
    ArrayRef<llvm::GlobalValue *> Container, StringRef SymbolName,
    StringRef SectionName) { … }

void CGObjCNonFragileABIMac::FinishNonFragileABIModule() { … }

/// isVTableDispatchedSelector - Returns true if SEL is not in the list of
/// VTableDispatchMethods; false otherwise. What this means is that
/// except for the 19 selectors in the list, we generate 32bit-style
/// message dispatch call for all the rest.
bool CGObjCNonFragileABIMac::isVTableDispatchedSelector(Selector Sel) { … }

/// BuildClassRoTInitializer - generate meta-data for:
/// struct _class_ro_t {
///   uint32_t const flags;
///   uint32_t const instanceStart;
///   uint32_t const instanceSize;
///   uint32_t const reserved;  // only when building for 64bit targets
///   const uint8_t * const ivarLayout;
///   const char *const name;
///   const struct _method_list_t * const baseMethods;
///   const struct _protocol_list_t *const baseProtocols;
///   const struct _ivar_list_t *const ivars;
///   const uint8_t * const weakIvarLayout;
///   const struct _prop_list_t * const properties;
/// }
///
llvm::GlobalVariable * CGObjCNonFragileABIMac::BuildClassRoTInitializer(
  unsigned flags,
  unsigned InstanceStart,
  unsigned InstanceSize,
  const ObjCImplementationDecl *ID) { … }

/// Build the metaclass object for a class.
///
/// struct _class_t {
///   struct _class_t *isa;
///   struct _class_t * const superclass;
///   void *cache;
///   IMP *vtable;
///   struct class_ro_t *ro;
/// }
///
llvm::GlobalVariable *
CGObjCNonFragileABIMac::BuildClassObject(const ObjCInterfaceDecl *CI,
                                         bool isMetaclass,
                                         llvm::Constant *IsAGV,
                                         llvm::Constant *SuperClassGV,
                                         llvm::Constant *ClassRoGV,
                                         bool HiddenVisibility) { … }

bool CGObjCNonFragileABIMac::ImplementationIsNonLazy(
    const ObjCImplDecl *OD) const { … }

void CGObjCNonFragileABIMac::GetClassSizeInfo(const ObjCImplementationDecl *OID,
                                              uint32_t &InstanceStart,
                                              uint32_t &InstanceSize) { … }

static llvm::GlobalValue::DLLStorageClassTypes getStorage(CodeGenModule &CGM,
                                                          StringRef Name) { … }

void CGObjCNonFragileABIMac::GenerateClass(const ObjCImplementationDecl *ID) { … }

/// GenerateProtocolRef - This routine is called to generate code for
/// a protocol reference expression; as in:
/// @code
///   @protocol(Proto1);
/// @endcode
/// It generates a weak reference to l_OBJC_PROTOCOL_REFERENCE_$_Proto1
/// which will hold address of the protocol meta-data.
///
llvm::Value *CGObjCNonFragileABIMac::GenerateProtocolRef(CodeGenFunction &CGF,
                                                         const ObjCProtocolDecl *PD) { … }

/// GenerateCategory - Build metadata for a category implementation.
/// struct _category_t {
///   const char * const name;
///   struct _class_t *const cls;
///   const struct _method_list_t * const instance_methods;
///   const struct _method_list_t * const class_methods;
///   const struct _protocol_list_t * const protocols;
///   const struct _prop_list_t * const properties;
///   const struct _prop_list_t * const class_properties;
///   const uint32_t size;
/// }
///
void CGObjCNonFragileABIMac::GenerateCategory(const ObjCCategoryImplDecl *OCD) { … }

/// emitMethodConstant - Return a struct objc_method constant.  If
/// forProtocol is true, the implementation will be null; otherwise,
/// the method must have a definition registered with the runtime.
///
/// struct _objc_method {
///   SEL _cmd;
///   char *method_type;
///   char *_imp;
/// }
void CGObjCNonFragileABIMac::emitMethodConstant(ConstantArrayBuilder &builder,
                                                const ObjCMethodDecl *MD,
                                                bool forProtocol) { … }

/// Build meta-data for method declarations.
///
/// struct _method_list_t {
///   uint32_t entsize;  // sizeof(struct _objc_method)
///   uint32_t method_count;
///   struct _objc_method method_list[method_count];
/// }
///
llvm::Constant *
CGObjCNonFragileABIMac::emitMethodList(Twine name, MethodListType kind,
                              ArrayRef<const ObjCMethodDecl *> methods) { … }

/// ObjCIvarOffsetVariable - Returns the ivar offset variable for
/// the given ivar.
llvm::GlobalVariable *
CGObjCNonFragileABIMac::ObjCIvarOffsetVariable(const ObjCInterfaceDecl *ID,
                                               const ObjCIvarDecl *Ivar) { … }

llvm::Constant *
CGObjCNonFragileABIMac::EmitIvarOffsetVar(const ObjCInterfaceDecl *ID,
                                          const ObjCIvarDecl *Ivar,
                                          unsigned long int Offset) { … }

/// EmitIvarList - Emit the ivar list for the given
/// implementation. The return value has type
/// IvarListnfABIPtrTy.
///  struct _ivar_t {
///   unsigned [long] int *offset;  // pointer to ivar offset location
///   char *name;
///   char *type;
///   uint32_t alignment;
///   uint32_t size;
/// }
/// struct _ivar_list_t {
///   uint32 entsize;  // sizeof(struct _ivar_t)
///   uint32 count;
///   struct _iver_t list[count];
/// }
///

llvm::Constant *CGObjCNonFragileABIMac::EmitIvarList(
  const ObjCImplementationDecl *ID) { … }

llvm::Constant *CGObjCNonFragileABIMac::GetOrEmitProtocolRef(
  const ObjCProtocolDecl *PD) { … }

/// GetOrEmitProtocol - Generate the protocol meta-data:
/// @code
/// struct _protocol_t {
///   id isa;  // NULL
///   const char * const protocol_name;
///   const struct _protocol_list_t * protocol_list; // super protocols
///   const struct method_list_t * const instance_methods;
///   const struct method_list_t * const class_methods;
///   const struct method_list_t *optionalInstanceMethods;
///   const struct method_list_t *optionalClassMethods;
///   const struct _prop_list_t * properties;
///   const uint32_t size;  // sizeof(struct _protocol_t)
///   const uint32_t flags;  // = 0
///   const char ** extendedMethodTypes;
///   const char *demangledName;
///   const struct _prop_list_t * class_properties;
/// }
/// @endcode
///

llvm::Constant *CGObjCNonFragileABIMac::GetOrEmitProtocol(
  const ObjCProtocolDecl *PD) { … }

/// EmitProtocolList - Generate protocol list meta-data:
/// @code
/// struct _protocol_list_t {
///   long protocol_count;   // Note, this is 32/64 bit
///   struct _protocol_t[protocol_count];
/// }
/// @endcode
///
llvm::Constant *
CGObjCNonFragileABIMac::EmitProtocolList(Twine Name,
                                      ObjCProtocolDecl::protocol_iterator begin,
                                      ObjCProtocolDecl::protocol_iterator end) { … }

/// EmitObjCValueForIvar - Code Gen for nonfragile ivar reference.
/// This code gen. amounts to generating code for:
/// @code
/// (type *)((char *)base + _OBJC_IVAR_$_.ivar;
/// @encode
///
LValue CGObjCNonFragileABIMac::EmitObjCValueForIvar(
                                               CodeGen::CodeGenFunction &CGF,
                                               QualType ObjectTy,
                                               llvm::Value *BaseValue,
                                               const ObjCIvarDecl *Ivar,
                                               unsigned CVRQualifiers) { … }

llvm::Value *
CGObjCNonFragileABIMac::EmitIvarOffset(CodeGen::CodeGenFunction &CGF,
                                       const ObjCInterfaceDecl *Interface,
                                       const ObjCIvarDecl *Ivar) { … }

static void appendSelectorForMessageRefTable(std::string &buffer,
                                             Selector selector) { … }

/// Emit a "vtable" message send.  We emit a weak hidden-visibility
/// struct, initially containing the selector pointer and a pointer to
/// a "fixup" variant of the appropriate objc_msgSend.  To call, we
/// load and call the function pointer, passing the address of the
/// struct as the second parameter.  The runtime determines whether
/// the selector is currently emitted using vtable dispatch; if so, it
/// substitutes a stub function which simply tail-calls through the
/// appropriate vtable slot, and if not, it substitues a stub function
/// which tail-calls objc_msgSend.  Both stubs adjust the selector
/// argument to correctly point to the selector.
RValue
CGObjCNonFragileABIMac::EmitVTableMessageSend(CodeGenFunction &CGF,
                                              ReturnValueSlot returnSlot,
                                              QualType resultType,
                                              Selector selector,
                                              llvm::Value *arg0,
                                              QualType arg0Type,
                                              bool isSuper,
                                              const CallArgList &formalArgs,
                                              const ObjCMethodDecl *method) { … }

/// Generate code for a message send expression in the nonfragile abi.
CodeGen::RValue
CGObjCNonFragileABIMac::GenerateMessageSend(CodeGen::CodeGenFunction &CGF,
                                            ReturnValueSlot Return,
                                            QualType ResultType,
                                            Selector Sel,
                                            llvm::Value *Receiver,
                                            const CallArgList &CallArgs,
                                            const ObjCInterfaceDecl *Class,
                                            const ObjCMethodDecl *Method) { … }

llvm::Constant *
CGObjCNonFragileABIMac::GetClassGlobal(const ObjCInterfaceDecl *ID,
                                       bool metaclass,
                                       ForDefinition_t isForDefinition) { … }

llvm::Constant *
CGObjCNonFragileABIMac::GetClassGlobal(StringRef Name,
                                       ForDefinition_t IsForDefinition,
                                       bool Weak, bool DLLImport) { … }

llvm::Constant *
CGObjCNonFragileABIMac::GetClassGlobalForClassRef(const ObjCInterfaceDecl *ID) { … }

llvm::Value *
CGObjCNonFragileABIMac::EmitLoadOfClassRef(CodeGenFunction &CGF,
                                           const ObjCInterfaceDecl *ID,
                                           llvm::GlobalVariable *Entry) { … }

llvm::Value *
CGObjCNonFragileABIMac::EmitClassRefFromId(CodeGenFunction &CGF,
                                           IdentifierInfo *II,
                                           const ObjCInterfaceDecl *ID) { … }

llvm::Value *CGObjCNonFragileABIMac::EmitClassRef(CodeGenFunction &CGF,
                                                  const ObjCInterfaceDecl *ID) { … }

llvm::Value *CGObjCNonFragileABIMac::EmitNSAutoreleasePoolClassRef(
                                                    CodeGenFunction &CGF) { … }

llvm::Value *
CGObjCNonFragileABIMac::EmitSuperClassRef(CodeGenFunction &CGF,
                                          const ObjCInterfaceDecl *ID) { … }

/// EmitMetaClassRef - Return a Value * of the address of _class_t
/// meta-data
///
llvm::Value *CGObjCNonFragileABIMac::EmitMetaClassRef(CodeGenFunction &CGF,
                                                      const ObjCInterfaceDecl *ID,
                                                      bool Weak) { … }

/// GetClass - Return a reference to the class for the given interface
/// decl.
llvm::Value *CGObjCNonFragileABIMac::GetClass(CodeGenFunction &CGF,
                                              const ObjCInterfaceDecl *ID) { … }

/// 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.
CodeGen::RValue
CGObjCNonFragileABIMac::GenerateMessageSendSuper(CodeGen::CodeGenFunction &CGF,
                                                 ReturnValueSlot Return,
                                                 QualType ResultType,
                                                 Selector Sel,
                                                 const ObjCInterfaceDecl *Class,
                                                 bool isCategoryImpl,
                                                 llvm::Value *Receiver,
                                                 bool IsClassMessage,
                                                 const CodeGen::CallArgList &CallArgs,
                                                 const ObjCMethodDecl *Method) { … }

llvm::Value *CGObjCNonFragileABIMac::EmitSelector(CodeGenFunction &CGF,
                                                  Selector Sel) { … }

ConstantAddress CGObjCNonFragileABIMac::EmitSelectorAddr(Selector Sel) { … }

/// EmitObjCIvarAssign - Code gen for assigning to a __strong object.
/// objc_assign_ivar (id src, id *dst, ptrdiff_t)
///
void CGObjCNonFragileABIMac::EmitObjCIvarAssign(CodeGen::CodeGenFunction &CGF,
                                                llvm::Value *src,
                                                Address dst,
                                                llvm::Value *ivarOffset) { … }

/// EmitObjCStrongCastAssign - Code gen for assigning to a __strong cast object.
/// objc_assign_strongCast (id src, id *dst)
///
void CGObjCNonFragileABIMac::EmitObjCStrongCastAssign(
  CodeGen::CodeGenFunction &CGF,
  llvm::Value *src, Address dst) { … }

void CGObjCNonFragileABIMac::EmitGCMemmoveCollectable(
    CodeGen::CodeGenFunction &CGF, Address DestPtr, Address SrcPtr,
    llvm::Value *Size) { … }

/// EmitObjCWeakRead - Code gen for loading value of a __weak
/// object: objc_read_weak (id *src)
///
llvm::Value * CGObjCNonFragileABIMac::EmitObjCWeakRead(
  CodeGen::CodeGenFunction &CGF,
  Address AddrWeakObj) { … }

/// EmitObjCWeakAssign - Code gen for assigning to a __weak object.
/// objc_assign_weak (id src, id *dst)
///
void CGObjCNonFragileABIMac::EmitObjCWeakAssign(CodeGen::CodeGenFunction &CGF,
                                                llvm::Value *src, Address dst) { … }

/// EmitObjCGlobalAssign - Code gen for assigning to a __strong object.
/// objc_assign_global (id src, id *dst)
///
void CGObjCNonFragileABIMac::EmitObjCGlobalAssign(CodeGen::CodeGenFunction &CGF,
                                          llvm::Value *src, Address dst,
                                          bool threadlocal) { … }

void
CGObjCNonFragileABIMac::EmitSynchronizedStmt(CodeGen::CodeGenFunction &CGF,
                                             const ObjCAtSynchronizedStmt &S) { … }

llvm::Constant *
CGObjCNonFragileABIMac::GetEHType(QualType T) { … }

void CGObjCNonFragileABIMac::EmitTryStmt(CodeGen::CodeGenFunction &CGF,
                                         const ObjCAtTryStmt &S) { … }

/// EmitThrowStmt - Generate code for a throw statement.
void CGObjCNonFragileABIMac::EmitThrowStmt(CodeGen::CodeGenFunction &CGF,
                                           const ObjCAtThrowStmt &S,
                                           bool ClearInsertionPoint) { … }

llvm::Constant *
CGObjCNonFragileABIMac::GetInterfaceEHType(const ObjCInterfaceDecl *ID,
                                           ForDefinition_t IsForDefinition) { … }

/* *** */

CodeGen::CGObjCRuntime *
CodeGen::CreateMacObjCRuntime(CodeGen::CodeGenModule &CGM) { … }