/usr/src/gnu/usr.bin/clang/libclangCodeGen/../../../llvm/clang/lib/CodeGen/CGObjCGNU.cpp

Bug Summary

File:	src/gnu/usr.bin/clang/libclangCodeGen/../../../llvm/clang/lib/CodeGen/CGObjCGNU.cpp
Warning:	line 1245, column 43 Called C++ object pointer is null

Annotated Source Code

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clang -cc1 -cc1 -triple amd64-unknown-openbsd7.0 -analyze -disable-free -disable-llvm-verifier -discard-value-names -main-file-name CGObjCGNU.cpp -analyzer-store=region -analyzer-opt-analyze-nested-blocks -analyzer-checker=core -analyzer-checker=apiModeling -analyzer-checker=unix -analyzer-checker=deadcode -analyzer-checker=cplusplus -analyzer-checker=security.insecureAPI.UncheckedReturn -analyzer-checker=security.insecureAPI.getpw -analyzer-checker=security.insecureAPI.gets -analyzer-checker=security.insecureAPI.mktemp -analyzer-checker=security.insecureAPI.mkstemp -analyzer-checker=security.insecureAPI.vfork -analyzer-checker=nullability.NullPassedToNonnull -analyzer-checker=nullability.NullReturnedFromNonnull -analyzer-output plist -w -setup-static-analyzer -mrelocation-model static -mframe-pointer=all -relaxed-aliasing -fno-rounding-math -mconstructor-aliases -munwind-tables -target-cpu x86-64 -tune-cpu generic -debugger-tuning=gdb -fcoverage-compilation-dir=/usr/src/gnu/usr.bin/clang/libclangCodeGen/obj -resource-dir /usr/local/lib/clang/13.0.0 -I /usr/src/gnu/usr.bin/clang/libclangCodeGen/../../../llvm/clang/include -I /usr/src/gnu/usr.bin/clang/libclangCodeGen/../../../llvm/llvm/include -I /usr/src/gnu/usr.bin/clang/libclangCodeGen/../include -I /usr/src/gnu/usr.bin/clang/libclangCodeGen/obj -I /usr/src/gnu/usr.bin/clang/libclangCodeGen/obj/../include -D NDEBUG -D __STDC_LIMIT_MACROS -D __STDC_CONSTANT_MACROS -D __STDC_FORMAT_MACROS -D LLVM_PREFIX="/usr" -internal-isystem /usr/include/c++/v1 -internal-isystem /usr/local/lib/clang/13.0.0/include -internal-externc-isystem /usr/include -O2 -Wno-unused-parameter -Wwrite-strings -Wno-missing-field-initializers -Wno-long-long -Wno-comment -std=c++14 -fdeprecated-macro -fdebug-compilation-dir=/usr/src/gnu/usr.bin/clang/libclangCodeGen/obj -ferror-limit 19 -fvisibility-inlines-hidden -fwrapv -stack-protector 2 -fno-rtti -fgnuc-version=4.2.1 -vectorize-loops -vectorize-slp -fno-builtin-malloc -fno-builtin-calloc -fno-builtin-realloc -fno-builtin-valloc -fno-builtin-free -fno-builtin-strdup -fno-builtin-strndup -analyzer-output=html -faddrsig -D__GCC_HAVE_DWARF2_CFI_ASM=1 -o /home/ben/Projects/vmm/scan-build/2022-01-12-194120-40624-1 -x c++ /usr/src/gnu/usr.bin/clang/libclangCodeGen/../../../llvm/clang/lib/CodeGen/CGObjCGNU.cpp

/usr/src/gnu/usr.bin/clang/libclangCodeGen/../../../llvm/clang/lib/CodeGen/CGObjCGNU.cpp

→

1//===------- CGObjCGNU.cpp - Emit LLVM Code from ASTs for a Module --------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// This provides Objective-C code generation targeting the GNU runtime.  The
10// class in this file generates structures used by the GNU Objective-C runtime
11// library.  These structures are defined in objc/objc.h and objc/objc-api.h in
12// the GNU runtime distribution.
13//
14//===----------------------------------------------------------------------===//

16#include "CGCXXABI.h"
17#include "CGCleanup.h"
18#include "CGObjCRuntime.h"
19#include "CodeGenFunction.h"
20#include "CodeGenModule.h"
21#include "clang/AST/ASTContext.h"
22#include "clang/AST/Attr.h"
23#include "clang/AST/Decl.h"
24#include "clang/AST/DeclObjC.h"
25#include "clang/AST/RecordLayout.h"
26#include "clang/AST/StmtObjC.h"
27#include "clang/Basic/FileManager.h"
28#include "clang/Basic/SourceManager.h"
29#include "clang/CodeGen/ConstantInitBuilder.h"
30#include "llvm/ADT/SmallVector.h"
31#include "llvm/ADT/StringMap.h"
32#include "llvm/IR/DataLayout.h"
33#include "llvm/IR/Intrinsics.h"
34#include "llvm/IR/LLVMContext.h"
35#include "llvm/IR/Module.h"
36#include "llvm/Support/Compiler.h"
37#include "llvm/Support/ConvertUTF.h"
38#include <cctype>

40using namespace clang;
41using namespace CodeGen;

43namespace {

45/// Class that lazily initialises the runtime function.  Avoids inserting the
46/// types and the function declaration into a module if they're not used, and
47/// avoids constructing the type more than once if it's used more than once.
48class LazyRuntimeFunction {
CodeGenModule *CGM;
llvm::FunctionType *FTy;
const char *FunctionName;
llvm::FunctionCallee Function;

54public:
/// Constructor leaves this class uninitialized, because it is intended to
/// be used as a field in another class and not all of the types that are
/// used as arguments will necessarily be available at construction time.
LazyRuntimeFunction()
    : CGM(nullptr), FunctionName(nullptr), Function(nullptr) {}

/// Initialises the lazy function with the name, return type, and the types
/// of the arguments.
template <typename... Tys>
void init(CodeGenModule *Mod, const char *name, llvm::Type *RetTy,
          Tys *... Types) {
  CGM = Mod;
  FunctionName = name;
  Function = nullptr;
  if(sizeof...(Tys)) {
    SmallVector<llvm::Type *, 8> ArgTys({Types...});
    FTy = llvm::FunctionType::get(RetTy, ArgTys, false);
  }
  else {
    FTy = llvm::FunctionType::get(RetTy, None, false);
  }
}

llvm::FunctionType *getType() { return FTy; }

/// Overloaded cast operator, allows the class to be implicitly cast to an
/// LLVM constant.
operator llvm::FunctionCallee() {
  if (!Function) {
    if (!FunctionName)
      return nullptr;
    Function = CGM->CreateRuntimeFunction(FTy, FunctionName);
  }
  return Function;
}
90};


93/// GNU Objective-C runtime code generation.  This class implements the parts of
94/// Objective-C support that are specific to the GNU family of runtimes (GCC,
95/// GNUstep and ObjFW).
96class CGObjCGNU : public CGObjCRuntime {
97protected:
/// The LLVM module into which output is inserted
llvm::Module &TheModule;
/// strut objc_super.  Used for sending messages to super.  This structure
/// contains the receiver (object) and the expected class.
llvm::StructType *ObjCSuperTy;
/// struct objc_super*.  The type of the argument to the superclass message
/// lookup functions.
llvm::PointerType *PtrToObjCSuperTy;
/// LLVM type for selectors.  Opaque pointer (i8*) unless a header declaring
/// SEL is included in a header somewhere, in which case it will be whatever
/// type is declared in that header, most likely {i8*, i8*}.
llvm::PointerType *SelectorTy;
/// LLVM i8 type.  Cached here to avoid repeatedly getting it in all of the
/// places where it's used
llvm::IntegerType *Int8Ty;
/// Pointer to i8 - LLVM type of char*, for all of the places where the
/// runtime needs to deal with C strings.
llvm::PointerType *PtrToInt8Ty;
/// struct objc_protocol type
llvm::StructType *ProtocolTy;
/// Protocol * type.
llvm::PointerType *ProtocolPtrTy;
/// Instance Method Pointer type.  This is a pointer to a function that takes,
/// at a minimum, an object and a selector, and is the generic type for
/// Objective-C methods.  Due to differences between variadic / non-variadic
/// calling conventions, it must always be cast to the correct type before
/// actually being used.
llvm::PointerType *IMPTy;
/// Type of an untyped Objective-C object.  Clang treats id as a built-in type
/// when compiling Objective-C code, so this may be an opaque pointer (i8*),
/// but if the runtime header declaring it is included then it may be a
/// pointer to a structure.
llvm::PointerType *IdTy;
/// Pointer to a pointer to an Objective-C object.  Used in the new ABI
/// message lookup function and some GC-related functions.
llvm::PointerType *PtrToIdTy;
/// The clang type of id.  Used when using the clang CGCall infrastructure to
/// call Objective-C methods.
CanQualType ASTIdTy;
/// LLVM type for C int type.
llvm::IntegerType *IntTy;
/// LLVM type for an opaque pointer.  This is identical to PtrToInt8Ty, but is
/// used in the code to document the difference between i8* meaning a pointer
/// to a C string and i8* meaning a pointer to some opaque type.
llvm::PointerType *PtrTy;
/// LLVM type for C long type.  The runtime uses this in a lot of places where
/// it should be using intptr_t, but we can't fix this without breaking
/// compatibility with GCC...
llvm::IntegerType *LongTy;
/// LLVM type for C size_t.  Used in various runtime data structures.
llvm::IntegerType *SizeTy;
/// LLVM type for C intptr_t.
llvm::IntegerType *IntPtrTy;
/// LLVM type for C ptrdiff_t.  Mainly used in property accessor functions.
llvm::IntegerType *PtrDiffTy;
/// LLVM type for C int*.  Used for GCC-ABI-compatible non-fragile instance
/// variables.
llvm::PointerType *PtrToIntTy;
/// LLVM type for Objective-C BOOL type.
llvm::Type *BoolTy;
/// 32-bit integer type, to save us needing to look it up every time it's used.
llvm::IntegerType *Int32Ty;
/// 64-bit integer type, to save us needing to look it up every time it's used.
llvm::IntegerType *Int64Ty;
/// The type of struct objc_property.
llvm::StructType *PropertyMetadataTy;
/// Metadata kind used to tie method lookups to message sends.  The GNUstep
/// runtime provides some LLVM passes that can use this to do things like
/// automatic IMP caching and speculative inlining.
unsigned msgSendMDKind;
/// Does the current target use SEH-based exceptions? False implies
/// Itanium-style DWARF unwinding.
bool usesSEHExceptions;

/// Helper to check if we are targeting a specific runtime version or later.
bool isRuntime(ObjCRuntime::Kind kind, unsigned major, unsigned minor=0) {
  const ObjCRuntime &R = CGM.getLangOpts().ObjCRuntime;
  return (R.getKind() == kind) &&
    (R.getVersion() >= VersionTuple(major, minor));
}

std::string ManglePublicSymbol(StringRef Name) {
  return (StringRef(CGM.getTriple().isOSBinFormatCOFF() ? "$_" : "._") + Name).str();
}

std::string SymbolForProtocol(Twine Name) {
  return (ManglePublicSymbol("OBJC_PROTOCOL_") + Name).str();
}

std::string SymbolForProtocolRef(StringRef Name) {
  return (ManglePublicSymbol("OBJC_REF_PROTOCOL_") + Name).str();
}


/// Helper function that generates a constant string and returns a pointer to
/// the start of the string.  The result of this function can be used anywhere
/// where the C code specifies const char*.
llvm::Constant *MakeConstantString(StringRef Str, const char *Name = "") {
  ConstantAddress Array =
      CGM.GetAddrOfConstantCString(std::string(Str), Name);
  return llvm::ConstantExpr::getGetElementPtr(Array.getElementType(),
                                              Array.getPointer(), Zeros);
}

/// Emits a linkonce_odr string, whose name is the prefix followed by the
/// string value.  This allows the linker to combine the strings between
/// different modules.  Used for EH typeinfo names, selector strings, and a
/// few other things.
llvm::Constant *ExportUniqueString(const std::string &Str,
                                   const std::string &prefix,
                                   bool Private=false) {
  std::string name = prefix + Str;
  auto *ConstStr = TheModule.getGlobalVariable(name);
  if (!ConstStr) {
    llvm::Constant *value = llvm::ConstantDataArray::getString(VMContext,Str);
    auto *GV = new llvm::GlobalVariable(TheModule, value->getType(), true,
            llvm::GlobalValue::LinkOnceODRLinkage, value, name);
    GV->setComdat(TheModule.getOrInsertComdat(name));
    if (Private)
      GV->setVisibility(llvm::GlobalValue::HiddenVisibility);
    ConstStr = GV;
  }
  return llvm::ConstantExpr::getGetElementPtr(ConstStr->getValueType(),
                                              ConstStr, Zeros);
}

/// Returns a property name and encoding string.
llvm::Constant *MakePropertyEncodingString(const ObjCPropertyDecl *PD,
                                           const Decl *Container) {
  assert(!isRuntime(ObjCRuntime::GNUstep, 2))((void)0);
  if (isRuntime(ObjCRuntime::GNUstep, 1, 6)) {
    std::string NameAndAttributes;
    std::string TypeStr =
      CGM.getContext().getObjCEncodingForPropertyDecl(PD, Container);
    NameAndAttributes += '\0';
    NameAndAttributes += TypeStr.length() + 3;
    NameAndAttributes += TypeStr;
    NameAndAttributes += '\0';
    NameAndAttributes += PD->getNameAsString();
    return MakeConstantString(NameAndAttributes);
  }
  return MakeConstantString(PD->getNameAsString());
}

/// Push the property attributes into two structure fields.
void PushPropertyAttributes(ConstantStructBuilder &Fields,
    const ObjCPropertyDecl *property, bool isSynthesized=true, bool
    isDynamic=true) {
  int attrs = property->getPropertyAttributes();
  // For read-only properties, clear the copy and retain flags
  if (attrs & ObjCPropertyAttribute::kind_readonly) {
    attrs &= ~ObjCPropertyAttribute::kind_copy;
    attrs &= ~ObjCPropertyAttribute::kind_retain;
    attrs &= ~ObjCPropertyAttribute::kind_weak;
    attrs &= ~ObjCPropertyAttribute::kind_strong;
  }
  // The first flags field has the same attribute values as clang uses internally
  Fields.addInt(Int8Ty, attrs & 0xff);
  attrs >>= 8;
  attrs <<= 2;
  // For protocol properties, synthesized and dynamic have no meaning, so we
  // reuse these flags to indicate that this is a protocol property (both set
  // has no meaning, as a property can't be both synthesized and dynamic)
  attrs |= isSynthesized ? (1<<0) : 0;
  attrs |= isDynamic ? (1<<1) : 0;
  // The second field is the next four fields left shifted by two, with the
  // low bit set to indicate whether the field is synthesized or dynamic.
  Fields.addInt(Int8Ty, attrs & 0xff);
  // Two padding fields
  Fields.addInt(Int8Ty, 0);
  Fields.addInt(Int8Ty, 0);
}

virtual llvm::Constant *GenerateCategoryProtocolList(const
    ObjCCategoryDecl *OCD);
virtual ConstantArrayBuilder PushPropertyListHeader(ConstantStructBuilder &Fields,
    int count) {
    // int count;
    Fields.addInt(IntTy, count);
    // int size; (only in GNUstep v2 ABI.
    if (isRuntime(ObjCRuntime::GNUstep, 2)) {
      llvm::DataLayout td(&TheModule);
      Fields.addInt(IntTy, td.getTypeSizeInBits(PropertyMetadataTy) /
          CGM.getContext().getCharWidth());
    }
    // struct objc_property_list *next;
    Fields.add(NULLPtr);
    // struct objc_property properties[]
    return Fields.beginArray(PropertyMetadataTy);
}
virtual void PushProperty(ConstantArrayBuilder &PropertiesArray,
          const ObjCPropertyDecl *property,
          const Decl *OCD,
          bool isSynthesized=true, bool
          isDynamic=true) {
  auto Fields = PropertiesArray.beginStruct(PropertyMetadataTy);
  ASTContext &Context = CGM.getContext();
  Fields.add(MakePropertyEncodingString(property, OCD));
  PushPropertyAttributes(Fields, property, isSynthesized, isDynamic);
  auto addPropertyMethod = [&](const ObjCMethodDecl *accessor) {
    if (accessor) {
      std::string TypeStr = Context.getObjCEncodingForMethodDecl(accessor);
      llvm::Constant *TypeEncoding = MakeConstantString(TypeStr);
      Fields.add(MakeConstantString(accessor->getSelector().getAsString()));
      Fields.add(TypeEncoding);
    } else {
      Fields.add(NULLPtr);
      Fields.add(NULLPtr);
    }
  };
  addPropertyMethod(property->getGetterMethodDecl());
  addPropertyMethod(property->getSetterMethodDecl());
  Fields.finishAndAddTo(PropertiesArray);
}

/// Ensures that the value has the required type, by inserting a bitcast if
/// required.  This function lets us avoid inserting bitcasts that are
/// redundant.
llvm::Value* EnforceType(CGBuilderTy &B, llvm::Value *V, llvm::Type *Ty) {
  if (V->getType() == Ty) return V;
  return B.CreateBitCast(V, Ty);
}
Address EnforceType(CGBuilderTy &B, Address V, llvm::Type *Ty) {
  if (V.getType() == Ty) return V;
  return B.CreateBitCast(V, Ty);
}

// Some zeros used for GEPs in lots of places.
llvm::Constant *Zeros[2];
/// Null pointer value.  Mainly used as a terminator in various arrays.
llvm::Constant *NULLPtr;
/// LLVM context.
llvm::LLVMContext &VMContext;

332protected:

/// 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;

385protected:
/// 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;

402private:
/// 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;

417protected:
/// 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);

564public:
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")__builtin_unreachable();
}
llvm::Constant *GetConstantSelector(const ObjCMethodDecl *M) {
  return GetConstantSelector(M->getSelector(),
      CGM.getContext().getObjCEncodingForMethodDecl(M));
}
llvm::Constant *GetEHType(QualType T) override;

llvm::Function *GenerateMethod(const ObjCMethodDecl *OMD,
                               const ObjCContainerDecl *CD) override;
void GenerateDirectMethodPrologue(CodeGenFunction &CGF, llvm::Function *Fn,
                                  const ObjCMethodDecl *OMD,
                                  const ObjCContainerDecl *CD) override;
void GenerateCategory(const ObjCCategoryImplDecl *CMD) override;
void GenerateClass(const ObjCImplementationDecl *ClassDecl) override;
void RegisterAlias(const ObjCCompatibleAliasDecl *OAD) override;
llvm::Value *GenerateProtocolRef(CodeGenFunction &CGF,
                                 const ObjCProtocolDecl *PD) override;
void GenerateProtocol(const ObjCProtocolDecl *PD) override;

virtual llvm::Constant *GenerateProtocolRef(const ObjCProtocolDecl *PD);

llvm::Constant *GetOrEmitProtocol(const ObjCProtocolDecl *PD) override {
  return GenerateProtocolRef(PD);
}

llvm::Function *ModuleInitFunction() override;
llvm::FunctionCallee GetPropertyGetFunction() override;
llvm::FunctionCallee GetPropertySetFunction() override;
llvm::FunctionCallee GetOptimizedPropertySetFunction(bool atomic,
                                                     bool copy) override;
llvm::FunctionCallee GetSetStructFunction() override;
llvm::FunctionCallee GetGetStructFunction() override;
llvm::FunctionCallee GetCppAtomicObjectGetFunction() override;
llvm::FunctionCallee GetCppAtomicObjectSetFunction() override;
llvm::FunctionCallee EnumerationMutationFunction() override;

void EmitTryStmt(CodeGenFunction &CGF,
                 const ObjCAtTryStmt &S) override;
void EmitSynchronizedStmt(CodeGenFunction &CGF,
                          const ObjCAtSynchronizedStmt &S) override;
void EmitThrowStmt(CodeGenFunction &CGF,
                   const ObjCAtThrowStmt &S,
                   bool ClearInsertionPoint=true) override;
llvm::Value * EmitObjCWeakRead(CodeGenFunction &CGF,
                               Address AddrWeakObj) override;
void EmitObjCWeakAssign(CodeGenFunction &CGF,
                        llvm::Value *src, Address dst) override;
void EmitObjCGlobalAssign(CodeGenFunction &CGF,
                          llvm::Value *src, Address dest,
                          bool threadlocal=false) override;
void EmitObjCIvarAssign(CodeGenFunction &CGF, llvm::Value *src,
                        Address dest, llvm::Value *ivarOffset) override;
void EmitObjCStrongCastAssign(CodeGenFunction &CGF,
                              llvm::Value *src, Address dest) override;
void EmitGCMemmoveCollectable(CodeGenFunction &CGF, Address DestPtr,
                              Address SrcPtr,
                              llvm::Value *Size) override;
LValue EmitObjCValueForIvar(CodeGenFunction &CGF, QualType ObjectTy,
                            llvm::Value *BaseValue, const ObjCIvarDecl *Ivar,
                            unsigned CVRQualifiers) override;
llvm::Value *EmitIvarOffset(CodeGenFunction &CGF,
                            const ObjCInterfaceDecl *Interface,
                            const ObjCIvarDecl *Ivar) override;
llvm::Value *EmitNSAutoreleasePoolClassRef(CodeGenFunction &CGF) override;
llvm::Constant *BuildGCBlockLayout(CodeGenModule &CGM,
                                   const CGBlockInfo &blockInfo) override {
  return NULLPtr;
}
llvm::Constant *BuildRCBlockLayout(CodeGenModule &CGM,
                                   const CGBlockInfo &blockInfo) override {
  return NULLPtr;
}

llvm::Constant *BuildByrefLayout(CodeGenModule &CGM, QualType T) override {
  return NULLPtr;
}
668};

670/// Class representing the legacy GCC Objective-C ABI.  This is the default when
671/// -fobjc-nonfragile-abi is not specified.
672///
673/// The GCC ABI target actually generates code that is approximately compatible
674/// with the new GNUstep runtime ABI, but refrains from using any features that
675/// would not work with the GCC runtime.  For example, clang always generates
676/// the extended form of the class structure, and the extra fields are simply
677/// ignored by GCC libobjc.
678class 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;

687protected:
llvm::Value *LookupIMP(CodeGenFunction &CGF, llvm::Value *&Receiver,
                       llvm::Value *cmd, llvm::MDNode *node,
                       MessageSendInfo &MSI) override {
  CGBuilderTy &Builder = CGF.Builder;
  llvm::Value *args[] = {
          EnforceType(Builder, Receiver, IdTy),
          EnforceType(Builder, cmd, SelectorTy) };
  llvm::CallBase *imp = CGF.EmitRuntimeCallOrInvoke(MsgLookupFn, args);
  imp->setMetadata(msgSendMDKind, node);
  return imp;
}

llvm::Value *LookupIMPSuper(CodeGenFunction &CGF, Address ObjCSuper,
                            llvm::Value *cmd, MessageSendInfo &MSI) override {
  CGBuilderTy &Builder = CGF.Builder;
  llvm::Value *lookupArgs[] = {EnforceType(Builder, ObjCSuper,
      PtrToObjCSuperTy).getPointer(), cmd};
  return CGF.EmitNounwindRuntimeCall(MsgLookupSuperFn, lookupArgs);
}

708public:
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);
}
716};

718/// Class used when targeting the new GNUstep runtime ABI.
719class 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 a slot structure pointer.  This is returned by the various
  /// lookup functions.
  llvm::Type *SlotTy;
  /// Type of a slot structure.
  llvm::Type *SlotStructTy;

public:
  llvm::Constant *GetEHType(QualType T) override;

protected:
  llvm::Value *LookupIMP(CodeGenFunction &CGF, llvm::Value *&Receiver,
                         llvm::Value *cmd, llvm::MDNode *node,
                         MessageSendInfo &MSI) override {
    CGBuilderTy &Builder = CGF.Builder;
    llvm::FunctionCallee LookupFn = SlotLookupFn;

    // Store the receiver on the stack so that we can reload it later
    Address ReceiverPtr =
      CGF.CreateTempAlloca(Receiver->getType(), CGF.getPointerAlign());
    Builder.CreateStore(Receiver, ReceiverPtr);

    llvm::Value *self;

    if (isa<ObjCMethodDecl>(CGF.CurCodeDecl)) {
      self = CGF.LoadObjCSelf();
    } else {
      self = llvm::ConstantPointerNull::get(IdTy);
    }

    // The lookup function is guaranteed not to capture the receiver pointer.
    if (auto *LookupFn2 = dyn_cast<llvm::Function>(LookupFn.getCallee()))
      LookupFn2->addParamAttr(0, llvm::Attribute::NoCapture);

    llvm::Value *args[] = {
            EnforceType(Builder, ReceiverPtr.getPointer(), PtrToIdTy),
            EnforceType(Builder, cmd, SelectorTy),
            EnforceType(Builder, self, IdTy) };
    llvm::CallBase *slot = CGF.EmitRuntimeCallOrInvoke(LookupFn, args);
    slot->setOnlyReadsMemory();
    slot->setMetadata(msgSendMDKind, node);

    // Load the imp from the slot
    llvm::Value *imp = Builder.CreateAlignedLoad(
        IMPTy, Builder.CreateStructGEP(SlotStructTy, slot, 4),
        CGF.getPointerAlign());

    // The lookup function may have changed the receiver, so make sure we use
    // the new one.
    Receiver = Builder.CreateLoad(ReceiverPtr, true);
    return imp;
  }

  llvm::Value *LookupIMPSuper(CodeGenFunction &CGF, Address ObjCSuper,
                              llvm::Value *cmd,
                              MessageSendInfo &MSI) override {
    CGBuilderTy &Builder = CGF.Builder;
    llvm::Value *lookupArgs[] = {ObjCSuper.getPointer(), cmd};

    llvm::CallInst *slot =
      CGF.EmitNounwindRuntimeCall(SlotLookupSuperFn, lookupArgs);
    slot->setOnlyReadsMemory();

    return Builder.CreateAlignedLoad(
        IMPTy, Builder.CreateStructGEP(SlotStructTy, 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;

    SlotStructTy = llvm::StructType::get(PtrTy, PtrTy, PtrTy, IntTy, IMPTy);
    SlotTy = llvm::PointerType::getUnqual(SlotStructTy);
    // Slot_t objc_msg_lookup_sender(id *receiver, SEL selector, id sender);
    SlotLookupFn.init(&CGM, "objc_msg_lookup_sender", SlotTy, PtrToIdTy,
                      SelectorTy, IdTy);
    // Slot_t objc_slot_lookup_super(struct objc_super*, SEL);
    SlotLookupSuperFn.init(&CGM, "objc_slot_lookup_super", SlotTy,
                           PtrToObjCSuperTy, SelectorTy);
    // If we're in ObjC++ mode, then we want to make
    if (usesSEHExceptions) {
        llvm::Type *VoidTy = llvm::Type::getVoidTy(VMContext);
        // void objc_exception_rethrow(void)
        ExceptionReThrowFn.init(&CGM, "objc_exception_rethrow", VoidTy);
    } else if (CGM.getLangOpts().CPlusPlus) {
      llvm::Type *VoidTy = llvm::Type::getVoidTy(VMContext);
      // void *__cxa_begin_catch(void *e)
      EnterCatchFn.init(&CGM, "__cxa_begin_catch", PtrTy, PtrTy);
      // void __cxa_end_catch(void)
      ExitCatchFn.init(&CGM, "__cxa_end_catch", VoidTy);
      // void _Unwind_Resume_or_Rethrow(void*)
      ExceptionReThrowFn.init(&CGM, "_Unwind_Resume_or_Rethrow", VoidTy,
                              PtrTy);
    } else if (R.getVersion() >= VersionTuple(1, 7)) {
      llvm::Type *VoidTy = llvm::Type::getVoidTy(VMContext);
      // id objc_begin_catch(void *e)
      EnterCatchFn.init(&CGM, "objc_begin_catch", IdTy, PtrTy);
      // void objc_end_catch(void)
      ExitCatchFn.init(&CGM, "objc_end_catch", VoidTy);
      // void _Unwind_Resume_or_Rethrow(void*)
      ExceptionReThrowFn.init(&CGM, "objc_exception_rethrow", VoidTy, PtrTy);
    }
    llvm::Type *VoidTy = llvm::Type::getVoidTy(VMContext);
    SetPropertyAtomic.init(&CGM, "objc_setProperty_atomic", VoidTy, IdTy,
                           SelectorTy, IdTy, PtrDiffTy);
    SetPropertyAtomicCopy.init(&CGM, "objc_setProperty_atomic_copy", VoidTy,
                               IdTy, SelectorTy, IdTy, PtrDiffTy);
    SetPropertyNonAtomic.init(&CGM, "objc_setProperty_nonatomic", VoidTy,
                              IdTy, SelectorTy, IdTy, PtrDiffTy);
    SetPropertyNonAtomicCopy.init(&CGM, "objc_setProperty_nonatomic_copy",
                                  VoidTy, IdTy, SelectorTy, IdTy, PtrDiffTy);
    // void objc_setCppObjectAtomic(void *dest, const void *src, void
    // *helper);
    CxxAtomicObjectSetFn.init(&CGM, "objc_setCppObjectAtomic", VoidTy, PtrTy,
                              PtrTy, PtrTy);
    // void objc_getCppObjectAtomic(void *dest, const void *src, void
    // *helper);
    CxxAtomicObjectGetFn.init(&CGM, "objc_getCppObjectAtomic", VoidTy, PtrTy,
                              PtrTy, PtrTy);
  }

  llvm::FunctionCallee GetCppAtomicObjectGetFunction() override {
    // The optimised functions were added in version 1.7 of the GNUstep
    // runtime.
    assert (CGM.getLangOpts().ObjCRuntime.getVersion() >=((void)0)
        VersionTuple(1, 7))((void)0);
    return CxxAtomicObjectGetFn;
  }

  llvm::FunctionCallee GetCppAtomicObjectSetFunction() override {
    // The optimised functions were added in version 1.7 of the GNUstep
    // runtime.
    assert (CGM.getLangOpts().ObjCRuntime.getVersion() >=((void)0)
        VersionTuple(1, 7))((void)0);
    return CxxAtomicObjectSetFn;
  }

  llvm::FunctionCallee GetOptimizedPropertySetFunction(bool atomic,
                                                       bool copy) override {
    // The optimised property functions omit the GC check, and so are not
    // safe to use in GC mode.  The standard functions are fast in GC mode,
    // so there is less advantage in using them.
    assert ((CGM.getLangOpts().getGC() == LangOptions::NonGC))((void)0);
    // The optimised functions were added in version 1.7 of the GNUstep
    // runtime.
    assert (CGM.getLangOpts().ObjCRuntime.getVersion() >=((void)0)
        VersionTuple(1, 7))((void)0);

    if (atomic) {
      if (copy) return SetPropertyAtomicCopy;
      return SetPropertyAtomic;
    }

    return copy ? SetPropertyNonAtomicCopy : SetPropertyNonAtomic;
  }
900};

902/// GNUstep Objective-C ABI version 2 implementation.
903/// This is the ABI that provides a clean break with the legacy GCC ABI and
904/// cleans up a number of things that were added to work around 1980s linkers.
905class CGObjCGNUstep2 : public CGObjCGNUstep {
enum SectionKind
{
  SelectorSection = 0,
  ClassSection,
  ClassReferenceSection,
  CategorySection,
  ProtocolSection,
  ProtocolReferenceSection,
  ClassAliasSection,
  ConstantStringSection
};
static const char *const SectionsBaseNames[8];
static const char *const PECOFFSectionsBaseNames[8];
template<SectionKind K>
std::string sectionName() {
  if (CGM.getTriple().isOSBinFormatCOFF()) {
    std::string name(PECOFFSectionsBaseNames[K]);
    name += "$m";
    return name;
  }
  return SectionsBaseNames[K];
}
/// The GCC ABI superclass message lookup function.  Takes a pointer to a
/// structure describing the receiver and the class, and a selector as
/// arguments.  Returns the IMP for the corresponding method.
LazyRuntimeFunction MsgLookupSuperFn;
/// A flag indicating if we've emitted at least one protocol.
/// If we haven't, then we need to emit an empty protocol, to ensure that the
/// __start__objc_protocols and __stop__objc_protocols sections exist.
bool EmittedProtocol = false;
/// A flag indicating if we've emitted at least one protocol reference.
/// If we haven't, then we need to emit an empty protocol, to ensure that the
/// __start__objc_protocol_refs and __stop__objc_protocol_refs sections
/// exist.
bool EmittedProtocolRef = false;
/// A flag indicating if we've emitted at least one class.
/// If we haven't, then we need to emit an empty protocol, to ensure that the
/// __start__objc_classes and __stop__objc_classes sections / exist.
bool EmittedClass = false;
/// Generate the name of a symbol for a reference to a class.  Accesses to
/// classes should be indirected via this.

typedef std::pair<std::string, std::pair<llvm::GlobalVariable*, int>>
    EarlyInitPair;
std::vector<EarlyInitPair> EarlyInitList;

std::string SymbolForClassRef(StringRef Name, bool isWeak) {
  if (isWeak)
    return (ManglePublicSymbol("OBJC_WEAK_REF_CLASS_") + Name).str();
  else
    return (ManglePublicSymbol("OBJC_REF_CLASS_") + Name).str();
}
/// Generate the name of a class symbol.
std::string SymbolForClass(StringRef Name) {
  return (ManglePublicSymbol("OBJC_CLASS_") + Name).str();
}
void CallRuntimeFunction(CGBuilderTy &B, StringRef FunctionName,
    ArrayRef<llvm::Value*> Args) {
  SmallVector<llvm::Type *,8> Types;
  for (auto *Arg : Args)
    Types.push_back(Arg->getType());
  llvm::FunctionType *FT = llvm::FunctionType::get(B.getVoidTy(), Types,
      false);
  llvm::FunctionCallee Fn = CGM.CreateRuntimeFunction(FT, FunctionName);
  B.CreateCall(Fn, Args);
}

ConstantAddress GenerateConstantString(const StringLiteral *SL) override {

  auto Str = SL->getString();
  CharUnits Align = CGM.getPointerAlign();

  // Look for an existing one
  llvm::StringMap<llvm::Constant*>::iterator old = ObjCStrings.find(Str);
  if (old != ObjCStrings.end())
    return ConstantAddress(old->getValue(), Align);

  bool isNonASCII = SL->containsNonAscii();

  auto LiteralLength = SL->getLength();

  if ((CGM.getTarget().getPointerWidth(0) == 64) &&
      (LiteralLength < 9) && !isNonASCII) {
    // Tiny strings are only used on 64-bit platforms.  They store 8 7-bit
    // ASCII characters in the high 56 bits, followed by a 4-bit length and a
    // 3-bit tag (which is always 4).
    uint64_t str = 0;
    // Fill in the characters
    for (unsigned i=0 ; i<LiteralLength ; i++)
      str |= ((uint64_t)SL->getCodeUnit(i)) << ((64 - 4 - 3) - (i*7));
    // Fill in the length
    str |= LiteralLength << 3;
    // Set the tag
    str |= 4;
    auto *ObjCStr = llvm::ConstantExpr::getIntToPtr(
        llvm::ConstantInt::get(Int64Ty, str), IdTy);
    ObjCStrings[Str] = ObjCStr;
    return ConstantAddress(ObjCStr, Align);
  }

  StringRef StringClass = CGM.getLangOpts().ObjCConstantStringClass;

  if (StringClass.empty()) StringClass = "NSConstantString";

  std::string Sym = SymbolForClass(StringClass);

  llvm::Constant *isa = TheModule.getNamedGlobal(Sym);

  if (!isa) {
    isa = new llvm::GlobalVariable(TheModule, IdTy, /* isConstant */false,
            llvm::GlobalValue::ExternalLinkage, nullptr, Sym);
    if (CGM.getTriple().isOSBinFormatCOFF()) {
      cast<llvm::GlobalValue>(isa)->setDLLStorageClass(llvm::GlobalValue::DLLImportStorageClass);
    }
  } else if (isa->getType() != PtrToIdTy)
    isa = llvm::ConstantExpr::getBitCast(isa, PtrToIdTy);

  //  struct
  //  {
  //    Class isa;
  //    uint32_t flags;
  //    uint32_t length; // Number of codepoints
  //    uint32_t size; // Number of bytes
  //    uint32_t hash;
  //    const char *data;
  //  };

  ConstantInitBuilder Builder(CGM);
  auto Fields = Builder.beginStruct();
  if (!CGM.getTriple().isOSBinFormatCOFF()) {
    Fields.add(isa);
  } else {
    Fields.addNullPointer(PtrTy);
  }
  // For now, all non-ASCII strings are represented as UTF-16.  As such, the
  // number of bytes is simply double the number of UTF-16 codepoints.  In
  // ASCII strings, the number of bytes is equal to the number of non-ASCII
  // codepoints.
  if (isNonASCII) {
    unsigned NumU8CodeUnits = Str.size();
    // A UTF-16 representation of a unicode string contains at most the same
    // number of code units as a UTF-8 representation.  Allocate that much
    // space, plus one for the final null character.
    SmallVector<llvm::UTF16, 128> ToBuf(NumU8CodeUnits + 1);
    const llvm::UTF8 *FromPtr = (const llvm::UTF8 *)Str.data();
    llvm::UTF16 *ToPtr = &ToBuf[0];
    (void)llvm::ConvertUTF8toUTF16(&FromPtr, FromPtr + NumU8CodeUnits,
        &ToPtr, ToPtr + NumU8CodeUnits, llvm::strictConversion);
    uint32_t StringLength = ToPtr - &ToBuf[0];
    // Add null terminator
    *ToPtr = 0;
    // Flags: 2 indicates UTF-16 encoding
    Fields.addInt(Int32Ty, 2);
    // Number of UTF-16 codepoints
    Fields.addInt(Int32Ty, StringLength);
    // Number of bytes
    Fields.addInt(Int32Ty, StringLength * 2);
    // Hash.  Not currently initialised by the compiler.
    Fields.addInt(Int32Ty, 0);
    // pointer to the data string.
    auto Arr = llvm::makeArrayRef(&ToBuf[0], ToPtr+1);
    auto *C = llvm::ConstantDataArray::get(VMContext, Arr);
    auto *Buffer = new llvm::GlobalVariable(TheModule, C->getType(),
        /*isConstant=*/true, llvm::GlobalValue::PrivateLinkage, C, ".str");
    Buffer->setUnnamedAddr(llvm::GlobalValue::UnnamedAddr::Global);
    Fields.add(Buffer);
  } else {
    // Flags: 0 indicates ASCII encoding
    Fields.addInt(Int32Ty, 0);
    // Number of UTF-16 codepoints, each ASCII byte is a UTF-16 codepoint
    Fields.addInt(Int32Ty, Str.size());
    // Number of bytes
    Fields.addInt(Int32Ty, Str.size());
    // Hash.  Not currently initialised by the compiler.
    Fields.addInt(Int32Ty, 0);
    // Data pointer
    Fields.add(MakeConstantString(Str));
  }
  std::string StringName;
  bool isNamed = !isNonASCII;
  if (isNamed) {
    StringName = ".objc_str_";
    for (int i=0,e=Str.size() ; i<e ; ++i) {
      unsigned char c = Str[i];
      if (isalnum(c))
        StringName += c;
      else if (c == ' ')
        StringName += '_';
      else {
        isNamed = false;
        break;
      }
    }
  }
  llvm::GlobalVariable *ObjCStrGV =
    Fields.finishAndCreateGlobal(
        isNamed ? StringRef(StringName) : ".objc_string",
        Align, false, isNamed ? llvm::GlobalValue::LinkOnceODRLinkage
                              : llvm::GlobalValue::PrivateLinkage);
  ObjCStrGV->setSection(sectionName<ConstantStringSection>());
  if (isNamed) {
    ObjCStrGV->setComdat(TheModule.getOrInsertComdat(StringName));
    ObjCStrGV->setVisibility(llvm::GlobalValue::HiddenVisibility);
  }
  if (CGM.getTriple().isOSBinFormatCOFF()) {
    std::pair<llvm::GlobalVariable*, int> v{ObjCStrGV, 0};
    EarlyInitList.emplace_back(Sym, v);
  }
  llvm::Constant *ObjCStr = llvm::ConstantExpr::getBitCast(ObjCStrGV, IdTy);
  ObjCStrings[Str] = ObjCStr;
  ConstantStrings.push_back(ObjCStr);
  return ConstantAddress(ObjCStr, Align);
}

void PushProperty(ConstantArrayBuilder &PropertiesArray,
          const ObjCPropertyDecl *property,
          const Decl *OCD,
          bool isSynthesized=true, bool
          isDynamic=true) override {
  // struct objc_property
  // {
  //   const char *name;
  //   const char *attributes;
  //   const char *type;
  //   SEL getter;
  //   SEL setter;
  // };
  auto Fields = PropertiesArray.beginStruct(PropertyMetadataTy);
  ASTContext &Context = CGM.getContext();
  Fields.add(MakeConstantString(property->getNameAsString()));
  std::string TypeStr =
    CGM.getContext().getObjCEncodingForPropertyDecl(property, OCD);
  Fields.add(MakeConstantString(TypeStr));
  std::string typeStr;
  Context.getObjCEncodingForType(property->getType(), typeStr);
  Fields.add(MakeConstantString(typeStr));
  auto addPropertyMethod = [&](const ObjCMethodDecl *accessor) {
    if (accessor) {
      std::string TypeStr = Context.getObjCEncodingForMethodDecl(accessor);
      Fields.add(GetConstantSelector(accessor->getSelector(), TypeStr));
    } else {
      Fields.add(NULLPtr);
    }
  };
  addPropertyMethod(property->getGetterMethodDecl());
  addPropertyMethod(property->getSetterMethodDecl());
  Fields.finishAndAddTo(PropertiesArray);
}

llvm::Constant *
GenerateProtocolMethodList(ArrayRef<const ObjCMethodDecl*> Methods) override {
  // struct objc_protocol_method_description
  // {
  //   SEL selector;
  //   const char *types;
  // };
  llvm::StructType *ObjCMethodDescTy =
    llvm::StructType::get(CGM.getLLVMContext(),
        { PtrToInt8Ty, PtrToInt8Ty });
  ASTContext &Context = CGM.getContext();
  ConstantInitBuilder Builder(CGM);
  // struct objc_protocol_method_description_list
  // {
  //   int count;
  //   int size;
  //   struct objc_protocol_method_description methods[];
  // };
  auto MethodList = Builder.beginStruct();
  // int count;
  MethodList.addInt(IntTy, Methods.size());
  // int size; // sizeof(struct objc_method_description)
  llvm::DataLayout td(&TheModule);
  MethodList.addInt(IntTy, td.getTypeSizeInBits(ObjCMethodDescTy) /
      CGM.getContext().getCharWidth());
  // struct objc_method_description[]
  auto MethodArray = MethodList.beginArray(ObjCMethodDescTy);
  for (auto *M : Methods) {
    auto Method = MethodArray.beginStruct(ObjCMethodDescTy);
    Method.add(CGObjCGNU::GetConstantSelector(M));
    Method.add(GetTypeString(Context.getObjCEncodingForMethodDecl(M, true)));
    Method.finishAndAddTo(MethodArray);
  }
  MethodArray.finishAndAddTo(MethodList);
  return MethodList.finishAndCreateGlobal(".objc_protocol_method_list",
                                          CGM.getPointerAlign());
}
llvm::Constant *GenerateCategoryProtocolList(const ObjCCategoryDecl *OCD)
  override {
  const auto &ReferencedProtocols = OCD->getReferencedProtocols();
  auto RuntimeProtocols = GetRuntimeProtocolList(ReferencedProtocols.begin(),
                                                 ReferencedProtocols.end());
  SmallVector<llvm::Constant *, 16> Protocols;
  for (const auto *PI : RuntimeProtocols)
    Protocols.push_back(
        llvm::ConstantExpr::getBitCast(GenerateProtocolRef(PI),
          ProtocolPtrTy));
  return GenerateProtocolList(Protocols);
}

llvm::Value *LookupIMPSuper(CodeGenFunction &CGF, Address ObjCSuper,
                            llvm::Value *cmd, MessageSendInfo &MSI) override {
  // Don't access the slot unless we're trying to cache the result.
  CGBuilderTy &Builder = CGF.Builder;
  llvm::Value *lookupArgs[] = {CGObjCGNU::EnforceType(Builder, ObjCSuper,
      PtrToObjCSuperTy).getPointer(), cmd};
  return CGF.EmitNounwindRuntimeCall(MsgLookupSuperFn, lookupArgs);
}

llvm::GlobalVariable *GetClassVar(StringRef Name, bool isWeak=false) {
  std::string SymbolName = SymbolForClassRef(Name, isWeak);
  auto *ClassSymbol = TheModule.getNamedGlobal(SymbolName);
  if (ClassSymbol)
13
←
Assuming 'ClassSymbol' is null→
14
←
Taking false branch→
    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 (isWeak14.1
'isWeak' is false
1
'isWeak' is false
)
15
←
Taking false branch→
    ClassSymbol->setInitializer(new llvm::GlobalVariable(TheModule,
        Int8Ty, false, llvm::GlobalValue::ExternalWeakLinkage,
        nullptr, SymbolForClass(Name)));
  else {
    if (CGM.getTriple().isOSBinFormatCOFF()) {
16
←
Calling 'Triple::isOSBinFormatCOFF'→
18
←
Returning from 'Triple::isOSBinFormatCOFF'→
19
←
Taking true branch→
      IdentifierInfo &II = CGM.getContext().Idents.get(Name);
      TranslationUnitDecl *TUDecl = CGM.getContext().getTranslationUnitDecl();
      DeclContext *DC = TranslationUnitDecl::castToDeclContext(TUDecl);

      const ObjCInterfaceDecl *OID = nullptr;
20
←
'OID' initialized to a null pointer value→
      for (const auto *Result : DC->lookup(&II))
        if ((OID = dyn_cast<ObjCInterfaceDecl>(Result)))
          break;

      // The first Interface we find may be a @class,
      // which should only be treated as the source of
      // truth in the absence of a true declaration.
      assert(OID && "Failed to find ObjCInterfaceDecl")((void)0);
      const ObjCInterfaceDecl *OIDDef = OID->getDefinition();
21
←
Called C++ object pointer is null
      if (OIDDef != nullptr)
        OID = OIDDef;

      auto Storage = llvm::GlobalValue::DefaultStorageClass;
      if (OID->hasAttr<DLLImportAttr>())
        Storage = llvm::GlobalValue::DLLImportStorageClass;
      else if (OID->hasAttr<DLLExportAttr>())
        Storage = llvm::GlobalValue::DLLExportStorageClass;

      cast<llvm::GlobalValue>(ClassSymbol)->setDLLStorageClass(Storage);
    }
  }
  assert(ClassSymbol->getName() == SymbolName)((void)0);
  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)((void)0);
      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!")__builtin_unreachable();
}

llvm::Constant *GenerateEmptyProtocol(StringRef ProtocolName) override {
  std::string Name = SymbolForProtocol(ProtocolName);
  auto *GV = TheModule.getGlobalVariable(Name);
  if (!GV) {
    // Emit a placeholder symbol.
    GV = new llvm::GlobalVariable(TheModule, ProtocolTy, false,
        llvm::GlobalValue::ExternalLinkage, nullptr, Name);
    GV->setAlignment(CGM.getPointerAlign().getAsAlign());
  }
  return llvm::ConstantExpr::getBitCast(GV, ProtocolPtrTy);
}

/// Existing protocol references.
llvm::StringMap<llvm::Constant*> ExistingProtocolRefs;

llvm::Value *GenerateProtocolRef(CodeGenFunction &CGF,
                                 const ObjCProtocolDecl *PD) override {
  auto Name = PD->getNameAsString();
  auto *&Ref = ExistingProtocolRefs[Name];
  if (!Ref) {
    auto *&Protocol = ExistingProtocols[Name];
    if (!Protocol)
      Protocol = GenerateProtocolRef(PD);
    std::string RefName = SymbolForProtocolRef(Name);
    assert(!TheModule.getGlobalVariable(RefName))((void)0);
    // Emit a reference symbol.
    auto GV = new llvm::GlobalVariable(TheModule, ProtocolPtrTy,
        false, llvm::GlobalValue::LinkOnceODRLinkage,
        llvm::ConstantExpr::getBitCast(Protocol, ProtocolPtrTy), RefName);
    GV->setComdat(TheModule.getOrInsertComdat(RefName));
    GV->setSection(sectionName<ProtocolReferenceSection>());
    GV->setAlignment(CGM.getPointerAlign().getAsAlign());
    Ref = GV;
  }
  EmittedProtocolRef = true;
  return CGF.Builder.CreateAlignedLoad(ProtocolPtrTy, Ref,
                                       CGM.getPointerAlign());
}

llvm::Constant *GenerateProtocolList(ArrayRef<llvm::Constant*> Protocols) {
  llvm::ArrayType *ProtocolArrayTy = llvm::ArrayType::get(ProtocolPtrTy,
      Protocols.size());
  llvm::Constant * ProtocolArray = llvm::ConstantArray::get(ProtocolArrayTy,
      Protocols);
  ConstantInitBuilder builder(CGM);
  auto ProtocolBuilder = builder.beginStruct();
  ProtocolBuilder.addNullPointer(PtrTy);
  ProtocolBuilder.addInt(SizeTy, Protocols.size());
  ProtocolBuilder.add(ProtocolArray);
  return ProtocolBuilder.finishAndCreateGlobal(".objc_protocol_list",
      CGM.getPointerAlign(), false, llvm::GlobalValue::InternalLinkage);
}

void GenerateProtocol(const ObjCProtocolDecl *PD) override {
  // Do nothing - we only emit referenced protocols.
}
llvm::Constant *GenerateProtocolRef(const ObjCProtocolDecl *PD) override {
  std::string ProtocolName = PD->getNameAsString();
  auto *&Protocol = ExistingProtocols[ProtocolName];
  if (Protocol)
    return Protocol;

  EmittedProtocol = true;

  auto SymName = SymbolForProtocol(ProtocolName);
  auto *OldGV = TheModule.getGlobalVariable(SymName);

  // Use the protocol definition, if there is one.
  if (const ObjCProtocolDecl *Def = PD->getDefinition())
    PD = Def;
  else {
    // If there is no definition, then create an external linkage symbol and
    // hope that someone else fills it in for us (and fail to link if they
    // don't).
    assert(!OldGV)((void)0);
    Protocol = new llvm::GlobalVariable(TheModule, ProtocolTy,
      /*isConstant*/false,
      llvm::GlobalValue::ExternalLinkage, nullptr, SymName);
    return Protocol;
  }

  SmallVector<llvm::Constant*, 16> Protocols;
  auto RuntimeProtocols =
      GetRuntimeProtocolList(PD->protocol_begin(), PD->protocol_end());
  for (const auto *PI : RuntimeProtocols)
    Protocols.push_back(
        llvm::ConstantExpr::getBitCast(GenerateProtocolRef(PI),
          ProtocolPtrTy));
  llvm::Constant *ProtocolList = GenerateProtocolList(Protocols);

  // Collect information about methods
  llvm::Constant *InstanceMethodList, *OptionalInstanceMethodList;
  llvm::Constant *ClassMethodList, *OptionalClassMethodList;
  EmitProtocolMethodList(PD->instance_methods(), InstanceMethodList,
      OptionalInstanceMethodList);
  EmitProtocolMethodList(PD->class_methods(), ClassMethodList,
      OptionalClassMethodList);

  // The isa pointer must be set to a magic number so the runtime knows it's
  // the correct layout.
  ConstantInitBuilder builder(CGM);
  auto ProtocolBuilder = builder.beginStruct();
  ProtocolBuilder.add(llvm::ConstantExpr::getIntToPtr(
        llvm::ConstantInt::get(Int32Ty, ProtocolVersion), IdTy));
  ProtocolBuilder.add(MakeConstantString(ProtocolName));
  ProtocolBuilder.add(ProtocolList);
  ProtocolBuilder.add(InstanceMethodList);
  ProtocolBuilder.add(ClassMethodList);
  ProtocolBuilder.add(OptionalInstanceMethodList);
  ProtocolBuilder.add(OptionalClassMethodList);
  // Required instance properties
  ProtocolBuilder.add(GeneratePropertyList(nullptr, PD, false, false));
  // Optional instance properties
  ProtocolBuilder.add(GeneratePropertyList(nullptr, PD, false, true));
  // Required class properties
  ProtocolBuilder.add(GeneratePropertyList(nullptr, PD, true, false));
  // Optional class properties
  ProtocolBuilder.add(GeneratePropertyList(nullptr, PD, true, true));

  auto *GV = ProtocolBuilder.finishAndCreateGlobal(SymName,
      CGM.getPointerAlign(), false, llvm::GlobalValue::ExternalLinkage);
  GV->setSection(sectionName<ProtocolSection>());
  GV->setComdat(TheModule.getOrInsertComdat(SymName));
  if (OldGV) {
    OldGV->replaceAllUsesWith(llvm::ConstantExpr::getBitCast(GV,
          OldGV->getType()));
    OldGV->removeFromParent();
    GV->setName(SymName);
  }
  Protocol = GV;
  return GV;
}
llvm::Constant *EnforceType(llvm::Constant *Val, llvm::Type *Ty) {
  if (Val->getType() == Ty)
    return Val;
  return llvm::ConstantExpr::getBitCast(Val, Ty);
}
llvm::Value *GetTypedSelector(CodeGenFunction &CGF, Selector Sel,
                              const std::string &TypeEncoding) override {
  return GetConstantSelector(Sel, TypeEncoding);
}
llvm::Constant  *GetTypeString(llvm::StringRef TypeEncoding) {
  if (TypeEncoding.empty())
    return NULLPtr;
  std::string MangledTypes = std::string(TypeEncoding);
  std::replace(MangledTypes.begin(), MangledTypes.end(),
    '@', '\1');
  std::string TypesVarName = ".objc_sel_types_" + MangledTypes;
  auto *TypesGlobal = TheModule.getGlobalVariable(TypesVarName);
  if (!TypesGlobal) {
    llvm::Constant *Init = llvm::ConstantDataArray::getString(VMContext,
        TypeEncoding);
    auto *GV = new llvm::GlobalVariable(TheModule, Init->getType(),
        true, llvm::GlobalValue::LinkOnceODRLinkage, Init, TypesVarName);
    GV->setComdat(TheModule.getOrInsertComdat(TypesVarName));
    GV->setVisibility(llvm::GlobalValue::HiddenVisibility);
    TypesGlobal = GV;
  }
  return llvm::ConstantExpr::getGetElementPtr(TypesGlobal->getValueType(),
      TypesGlobal, Zeros);
}
llvm::Constant *GetConstantSelector(Selector Sel,
                                    const std::string &TypeEncoding) override {
  // @ is used as a special character in symbol names (used for symbol
  // versioning), so mangle the name to not include it.  Replace it with a
  // character that is not a valid type encoding character (and, being
  // non-printable, never will be!)
  std::string MangledTypes = TypeEncoding;
  std::replace(MangledTypes.begin(), MangledTypes.end(),
    '@', '\1');
  auto SelVarName = (StringRef(".objc_selector_") + Sel.getAsString() + "_" +
    MangledTypes).str();
  if (auto *GV = TheModule.getNamedGlobal(SelVarName))
    return EnforceType(GV, SelectorTy);
  ConstantInitBuilder builder(CGM);
  auto SelBuilder = builder.beginStruct();
  SelBuilder.add(ExportUniqueString(Sel.getAsString(), ".objc_sel_name_",
        true));
  SelBuilder.add(GetTypeString(TypeEncoding));
  auto *GV = SelBuilder.finishAndCreateGlobal(SelVarName,
      CGM.getPointerAlign(), false, llvm::GlobalValue::LinkOnceODRLinkage);
  GV->setComdat(TheModule.getOrInsertComdat(SelVarName));
  GV->setVisibility(llvm::GlobalValue::HiddenVisibility);
  GV->setSection(sectionName<SelectorSection>());
  auto *SelVal = EnforceType(GV, SelectorTy);
  return SelVal;
}
llvm::StructType *emptyStruct = nullptr;

/// Return pointers to the start and end of a section.  On ELF platforms, we
/// use the __start_ and __stop_ symbols that GNU-compatible linkers will set
/// to the start and end of section names, as long as those section names are
/// valid identifiers and the symbols are referenced but not defined.  On
/// Windows, we use the fact that MSVC-compatible linkers will lexically sort
/// by subsections and place everything that we want to reference in a middle
/// subsection and then insert zero-sized symbols in subsections a and z.
std::pair<llvm::Constant*,llvm::Constant*>
GetSectionBounds(StringRef Section) {
  if (CGM.getTriple().isOSBinFormatCOFF()) {
    if (emptyStruct == nullptr) {
      emptyStruct = llvm::StructType::create(VMContext, ".objc_section_sentinel");
      emptyStruct->setBody({}, /*isPacked*/true);
    }
    auto ZeroInit = llvm::Constant::getNullValue(emptyStruct);
    auto Sym = [&](StringRef Prefix, StringRef SecSuffix) {
      auto *Sym = new llvm::GlobalVariable(TheModule, emptyStruct,
          /*isConstant*/false,
          llvm::GlobalValue::LinkOnceODRLinkage, ZeroInit, Prefix +
          Section);
      Sym->setVisibility(llvm::GlobalValue::HiddenVisibility);
      Sym->setSection((Section + SecSuffix).str());
      Sym->setComdat(TheModule.getOrInsertComdat((Prefix +
          Section).str()));
      Sym->setAlignment(CGM.getPointerAlign().getAsAlign());
      return Sym;
    };
    return { Sym("__start_", "$a"), Sym("__stop", "$z") };
  }
  auto *Start = new llvm::GlobalVariable(TheModule, PtrTy,
      /*isConstant*/false,
      llvm::GlobalValue::ExternalLinkage, nullptr, StringRef("__start_") +
      Section);
  Start->setVisibility(llvm::GlobalValue::HiddenVisibility);
  auto *Stop = new llvm::GlobalVariable(TheModule, PtrTy,
      /*isConstant*/false,
      llvm::GlobalValue::ExternalLinkage, nullptr, StringRef("__stop_") +
      Section);
  Stop->setVisibility(llvm::GlobalValue::HiddenVisibility);
  return { Start, Stop };
}
CatchTypeInfo getCatchAllTypeInfo() override {
  return CGM.getCXXABI().getCatchAllTypeInfo();
}
llvm::Function *ModuleInitFunction() override {
  llvm::Function *LoadFunction = llvm::Function::Create(
    llvm::FunctionType::get(llvm::Type::getVoidTy(VMContext), false),
    llvm::GlobalValue::LinkOnceODRLinkage, ".objcv2_load_function",
    &TheModule);
  LoadFunction->setVisibility(llvm::GlobalValue::HiddenVisibility);
  LoadFunction->setComdat(TheModule.getOrInsertComdat(".objcv2_load_function"));

  llvm::BasicBlock *EntryBB =
      llvm::BasicBlock::Create(VMContext, "entry", LoadFunction);
  CGBuilderTy B(CGM, VMContext);
  B.SetInsertPoint(EntryBB);
  ConstantInitBuilder builder(CGM);
  auto InitStructBuilder = builder.beginStruct();
  InitStructBuilder.addInt(Int64Ty, 0);
  auto &sectionVec = CGM.getTriple().isOSBinFormatCOFF() ? PECOFFSectionsBaseNames : SectionsBaseNames;
  for (auto *s : sectionVec) {
    auto bounds = GetSectionBounds(s);
    InitStructBuilder.add(bounds.first);
    InitStructBuilder.add(bounds.second);
  }
  auto *InitStruct = InitStructBuilder.finishAndCreateGlobal(".objc_init",
      CGM.getPointerAlign(), false, llvm::GlobalValue::LinkOnceODRLinkage);
  InitStruct->setVisibility(llvm::GlobalValue::HiddenVisibility);
  InitStruct->setComdat(TheModule.getOrInsertComdat(".objc_init"));

  CallRuntimeFunction(B, "__objc_load", {InitStruct});;
  B.CreateRetVoid();
  // Make sure that the optimisers don't delete this function.
  CGM.addCompilerUsedGlobal(LoadFunction);
  // FIXME: Currently ELF only!
  // We have to do this by hand, rather than with @llvm.ctors, so that the
  // linker can remove the duplicate invocations.
  auto *InitVar = new llvm::GlobalVariable(TheModule, LoadFunction->getType(),
      /*isConstant*/false, llvm::GlobalValue::LinkOnceAnyLinkage,
      LoadFunction, ".objc_ctor");
  // Check that this hasn't been renamed.  This shouldn't happen, because
  // this function should be called precisely once.
  assert(InitVar->getName() == ".objc_ctor")((void)0);
  // In Windows, initialisers are sorted by the suffix.  XCL is for library
  // initialisers, which run before user initialisers.  We are running
  // Objective-C loads at the end of library load.  This means +load methods
  // will run before any other static constructors, but that static
  // constructors can see a fully initialised Objective-C state.
  if (CGM.getTriple().isOSBinFormatCOFF())
      InitVar->setSection(".CRT$XCLz");
  else
  {
    if (CGM.getCodeGenOpts().UseInitArray)
      InitVar->setSection(".init_array");
    else
      InitVar->setSection(".ctors");
  }
  InitVar->setVisibility(llvm::GlobalValue::HiddenVisibility);
  InitVar->setComdat(TheModule.getOrInsertComdat(".objc_ctor"));
  CGM.addUsedGlobal(InitVar);
  for (auto *C : Categories) {
    auto *Cat = cast<llvm::GlobalVariable>(C->stripPointerCasts());
    Cat->setSection(sectionName<CategorySection>());
    CGM.addUsedGlobal(Cat);
  }
  auto createNullGlobal = [&](StringRef Name, ArrayRef<llvm::Constant*> Init,
      StringRef Section) {
    auto nullBuilder = builder.beginStruct();
    for (auto *F : Init)
      nullBuilder.add(F);
    auto GV = nullBuilder.finishAndCreateGlobal(Name, CGM.getPointerAlign(),
        false, llvm::GlobalValue::LinkOnceODRLinkage);
    GV->setSection(Section);
    GV->setComdat(TheModule.getOrInsertComdat(Name));
    GV->setVisibility(llvm::GlobalValue::HiddenVisibility);
    CGM.addUsedGlobal(GV);
    return GV;
  };
  for (auto clsAlias : ClassAliases)
    createNullGlobal(std::string(".objc_class_alias") +
        clsAlias.second, { MakeConstantString(clsAlias.second),
        GetClassVar(clsAlias.first) }, sectionName<ClassAliasSection>());
  // On ELF platforms, add a null value for each special section so that we
  // can always guarantee that the _start and _stop symbols will exist and be
  // meaningful.  This is not required on COFF platforms, where our start and
  // stop symbols will create the section.
  if (!CGM.getTriple().isOSBinFormatCOFF()) {
    createNullGlobal(".objc_null_selector", {NULLPtr, NULLPtr},
        sectionName<SelectorSection>());
    if (Categories.empty())
      createNullGlobal(".objc_null_category", {NULLPtr, NULLPtr,
                    NULLPtr, NULLPtr, NULLPtr, NULLPtr, NULLPtr},
          sectionName<CategorySection>());
    if (!EmittedClass) {
      createNullGlobal(".objc_null_cls_init_ref", NULLPtr,
          sectionName<ClassSection>());
      createNullGlobal(".objc_null_class_ref", { NULLPtr, NULLPtr },
          sectionName<ClassReferenceSection>());
    }
    if (!EmittedProtocol)
      createNullGlobal(".objc_null_protocol", {NULLPtr, NULLPtr, NULLPtr,
          NULLPtr, NULLPtr, NULLPtr, NULLPtr, NULLPtr, NULLPtr, NULLPtr,
          NULLPtr}, sectionName<ProtocolSection>());
    if (!EmittedProtocolRef)
      createNullGlobal(".objc_null_protocol_ref", {NULLPtr},
          sectionName<ProtocolReferenceSection>());
    if (ClassAliases.empty())
      createNullGlobal(".objc_null_class_alias", { NULLPtr, NULLPtr },
          sectionName<ClassAliasSection>());
    if (ConstantStrings.empty()) {
      auto i32Zero = llvm::ConstantInt::get(Int32Ty, 0);
      createNullGlobal(".objc_null_constant_string", { NULLPtr, i32Zero,
          i32Zero, i32Zero, i32Zero, NULLPtr },
          sectionName<ConstantStringSection>());
    }
  }
  ConstantStrings.clear();
  Categories.clear();
  Classes.clear();

  if (EarlyInitList.size() > 0) {
    auto *Init = llvm::Function::Create(llvm::FunctionType::get(CGM.VoidTy,
          {}), llvm::GlobalValue::InternalLinkage, ".objc_early_init",
        &CGM.getModule());
    llvm::IRBuilder<> b(llvm::BasicBlock::Create(CGM.getLLVMContext(), "entry",
          Init));
    for (const auto &lateInit : EarlyInitList) {
      auto *global = TheModule.getGlobalVariable(lateInit.first);
      if (global) {
        llvm::GlobalVariable *GV = lateInit.second.first;
        b.CreateAlignedStore(
            global,
            b.CreateStructGEP(GV->getValueType(), GV, lateInit.second.second),
            CGM.getPointerAlign().getAsAlign());
      }
    }
    b.CreateRetVoid();
    // We can't use the normal LLVM global initialisation array, because we
    // need to specify that this runs early in library initialisation.
    auto *InitVar = new llvm::GlobalVariable(CGM.getModule(), Init->getType(),
        /*isConstant*/true, llvm::GlobalValue::InternalLinkage,
        Init, ".objc_early_init_ptr");
    InitVar->setSection(".CRT$XCLb");
    CGM.addUsedGlobal(InitVar);
  }
  return nullptr;
}
/// In the v2 ABI, ivar offset variables use the type encoding in their name
/// to trigger linker failures if the types don't match.
std::string GetIVarOffsetVariableName(const ObjCInterfaceDecl *ID,
                                      const ObjCIvarDecl *Ivar) override {
  std::string TypeEncoding;
  CGM.getContext().getObjCEncodingForType(Ivar->getType(), TypeEncoding);
  // Prevent the @ from being interpreted as a symbol version.
  std::replace(TypeEncoding.begin(), TypeEncoding.end(),
    '@', '\1');
  const std::string Name = "__objc_ivar_offset_" + ID->getNameAsString()
    + '.' + Ivar->getNameAsString() + '.' + TypeEncoding;
  return Name;
}
llvm::Value *EmitIvarOffset(CodeGenFunction &CGF,
                            const ObjCInterfaceDecl *Interface,
                            const ObjCIvarDecl *Ivar) override {
  const std::string Name = GetIVarOffsetVariableName(Ivar->getContainingInterface(), Ivar);
  llvm::GlobalVariable *IvarOffsetPointer = TheModule.getNamedGlobal(Name);
  if (!IvarOffsetPointer)
    IvarOffsetPointer = new llvm::GlobalVariable(TheModule, IntTy, false,
            llvm::GlobalValue::ExternalLinkage, nullptr, Name);
  CharUnits Align = CGM.getIntAlign();
  llvm::Value *Offset =
      CGF.Builder.CreateAlignedLoad(IntTy, IvarOffsetPointer, Align);
  if (Offset->getType() != PtrDiffTy)
    Offset = CGF.Builder.CreateZExtOrBitCast(Offset, PtrDiffTy);
  return Offset;
}
void GenerateClass(const ObjCImplementationDecl *OID) override {
  ASTContext &Context = CGM.getContext();
  bool IsCOFF = CGM.getTriple().isOSBinFormatCOFF();

  // Get the class name
  ObjCInterfaceDecl *classDecl =
      const_cast<ObjCInterfaceDecl *>(OID->getClassInterface());
  std::string className = classDecl->getNameAsString();
  auto *classNameConstant = MakeConstantString(className);

  ConstantInitBuilder builder(CGM);
  auto metaclassFields = builder.beginStruct();
  // struct objc_class *isa;
  metaclassFields.addNullPointer(PtrTy);
  // struct objc_class *super_class;
  metaclassFields.addNullPointer(PtrTy);
  // const char *name;
  metaclassFields.add(classNameConstant);
  // long version;
  metaclassFields.addInt(LongTy, 0);
  // unsigned long info;
  // objc_class_flag_meta
  metaclassFields.addInt(LongTy, 1);
  // long instance_size;
  // Setting this to zero is consistent with the older ABI, but it might be
  // more sensible to set this to sizeof(struct objc_class)
  metaclassFields.addInt(LongTy, 0);
  // struct objc_ivar_list *ivars;
  metaclassFields.addNullPointer(PtrTy);
  // struct objc_method_list *methods
  // FIXME: Almost identical code is copied and pasted below for the
  // class, but refactoring it cleanly requires C++14 generic lambdas.
  if (OID->classmeth_begin() == OID->classmeth_end())
1
Taking false branch→
    metaclassFields.addNullPointer(PtrTy);
  else {
    SmallVector<ObjCMethodDecl*, 16> ClassMethods;
    ClassMethods.insert(ClassMethods.begin(), OID->classmeth_begin(),
        OID->classmeth_end());
    metaclassFields.addBitCast(
            GenerateMethodList(className, "", ClassMethods, true),
            PtrTy);
  }
  // void *dtable;
  metaclassFields.addNullPointer(PtrTy);
  // IMP cxx_construct;
  metaclassFields.addNullPointer(PtrTy);
  // IMP cxx_destruct;
  metaclassFields.addNullPointer(PtrTy);
  // struct objc_class *subclass_list
  metaclassFields.addNullPointer(PtrTy);
  // struct objc_class *sibling_class
  metaclassFields.addNullPointer(PtrTy);
  // struct objc_protocol_list *protocols;
  metaclassFields.addNullPointer(PtrTy);
  // struct reference_list *extra_data;
  metaclassFields.addNullPointer(PtrTy);
  // long abi_version;
  metaclassFields.addInt(LongTy, 0);
  // struct objc_property_list *properties
  metaclassFields.add(GeneratePropertyList(OID, classDecl, /*isClassProperty*/true));

  auto *metaclass = metaclassFields.finishAndCreateGlobal(
      ManglePublicSymbol("OBJC_METACLASS_") + className,
      CGM.getPointerAlign());

  auto classFields = builder.beginStruct();
  // struct objc_class *isa;
  classFields.add(metaclass);
  // struct objc_class *super_class;
  // Get the superclass name.
  const ObjCInterfaceDecl * SuperClassDecl =
    OID->getClassInterface()->getSuperClass();
  llvm::Constant *SuperClass = nullptr;
  if (SuperClassDecl) {
2
←
Assuming 'SuperClassDecl' is null→
3
←
Taking false branch→
    auto SuperClassName = SymbolForClass(SuperClassDecl->getNameAsString());
    SuperClass = TheModule.getNamedGlobal(SuperClassName);
    if (!SuperClass)
    {
      SuperClass = new llvm::GlobalVariable(TheModule, PtrTy, false,
          llvm::GlobalValue::ExternalLinkage, nullptr, SuperClassName);
      if (IsCOFF) {
        auto Storage = llvm::GlobalValue::DefaultStorageClass;
        if (SuperClassDecl->hasAttr<DLLImportAttr>())
          Storage = llvm::GlobalValue::DLLImportStorageClass;
        else if (SuperClassDecl->hasAttr<DLLExportAttr>())
          Storage = llvm::GlobalValue::DLLExportStorageClass;

        cast<llvm::GlobalValue>(SuperClass)->setDLLStorageClass(Storage);
      }
    }
    if (!IsCOFF)
      classFields.add(llvm::ConstantExpr::getBitCast(SuperClass, PtrTy));
    else
      classFields.addNullPointer(PtrTy);
  } else
    classFields.addNullPointer(PtrTy);
  // const char *name;
  classFields.add(classNameConstant);
  // long version;
  classFields.addInt(LongTy, 0);
  // unsigned long info;
  // !objc_class_flag_meta
  classFields.addInt(LongTy, 0);
  // long instance_size;
  int superInstanceSize = !SuperClassDecl3.1
'SuperClassDecl' is null
1
'SuperClassDecl' is null
 ? 0 :
4
←
'?' condition is true→
    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)
5
←
Assuming the condition is false→
6
←
Taking false branch→
    classFields.addNullPointer(PtrTy);
  else {
    int ivar_count = 0;
    for (const ObjCIvarDecl *IVD = classDecl->all_declared_ivar_begin(); IVD;
7
←
Loop condition is false. Execution continues on line 1822→
         IVD = IVD->getNextIvar()) ivar_count++;
    llvm::DataLayout td(&TheModule);
    // struct objc_ivar_list *ivars;
    ConstantInitBuilder b(CGM);
    auto ivarListBuilder = b.beginStruct();
    // int count;
    ivarListBuilder.addInt(IntTy, ivar_count);
    // size_t size;
    llvm::StructType *ObjCIvarTy = llvm::StructType::get(
      PtrToInt8Ty,
      PtrToInt8Ty,
      PtrToInt8Ty,
      Int32Ty,
      Int32Ty);
    ivarListBuilder.addInt(SizeTy, td.getTypeSizeInBits(ObjCIvarTy) /
        CGM.getContext().getCharWidth());
    // struct objc_ivar ivars[]
    auto ivarArrayBuilder = ivarListBuilder.beginArray();
    for (const ObjCIvarDecl *IVD = classDecl->all_declared_ivar_begin(); IVD;
8
←
Loop condition is false. Execution continues on line 1887→
         IVD = IVD->getNextIvar()) {
      auto ivarTy = IVD->getType();
      auto ivarBuilder = ivarArrayBuilder.beginStruct();
      // const char *name;
      ivarBuilder.add(MakeConstantString(IVD->getNameAsString()));
      // const char *type;
      std::string TypeStr;
      //Context.getObjCEncodingForType(ivarTy, TypeStr, IVD, true);
      Context.getObjCEncodingForMethodParameter(Decl::OBJC_TQ_None, ivarTy, TypeStr, true);
      ivarBuilder.add(MakeConstantString(TypeStr));
      // int *offset;
      uint64_t BaseOffset = ComputeIvarBaseOffset(CGM, OID, IVD);
      uint64_t Offset = BaseOffset - superInstanceSize;
      llvm::Constant *OffsetValue = llvm::ConstantInt::get(IntTy, Offset);
      std::string OffsetName = GetIVarOffsetVariableName(classDecl, IVD);
      llvm::GlobalVariable *OffsetVar = TheModule.getGlobalVariable(OffsetName);
      if (OffsetVar)
        OffsetVar->setInitializer(OffsetValue);
      else
        OffsetVar = new llvm::GlobalVariable(TheModule, IntTy,
          false, llvm::GlobalValue::ExternalLinkage,
          OffsetValue, OffsetName);
      auto ivarVisibility =
          (IVD->getAccessControl() == ObjCIvarDecl::Private ||
           IVD->getAccessControl() == ObjCIvarDecl::Package ||
           classDecl->getVisibility() == HiddenVisibility) ?
                  llvm::GlobalValue::HiddenVisibility :
                  llvm::GlobalValue::DefaultVisibility;
      OffsetVar->setVisibility(ivarVisibility);
      ivarBuilder.add(OffsetVar);
      // Ivar size
      ivarBuilder.addInt(Int32Ty,
          CGM.getContext().getTypeSizeInChars(ivarTy).getQuantity());
      // Alignment will be stored as a base-2 log of the alignment.
      unsigned align =
          llvm::Log2_32(Context.getTypeAlignInChars(ivarTy).getQuantity());
      // Objects that require more than 2^64-byte alignment should be impossible!
      assert(align < 64)((void)0);
      // uint32_t flags;
      // Bits 0-1 are ownership.
      // Bit 2 indicates an extended type encoding
      // Bits 3-8 contain log2(aligment)
      ivarBuilder.addInt(Int32Ty,
          (align << 3) | (1<<2) |
          FlagsForOwnership(ivarTy.getQualifiers().getObjCLifetime()));
      ivarBuilder.finishAndAddTo(ivarArrayBuilder);
    }
    ivarArrayBuilder.finishAndAddTo(ivarListBuilder);
    auto ivarList = ivarListBuilder.finishAndCreateGlobal(".objc_ivar_list",
        CGM.getPointerAlign(), /*constant*/ false,
        llvm::GlobalValue::PrivateLinkage);
    classFields.add(ivarList);
  }
  // struct objc_method_list *methods
  SmallVector<const ObjCMethodDecl*, 16> InstanceMethods;
  InstanceMethods.insert(InstanceMethods.begin(), OID->instmeth_begin(),
      OID->instmeth_end());
  for (auto *propImpl : OID->property_impls())
    if (propImpl->getPropertyImplementation() ==
        ObjCPropertyImplDecl::Synthesize) {
      auto addIfExists = [&](const ObjCMethodDecl *OMD) {
        if (OMD && OMD->hasBody())
          InstanceMethods.push_back(OMD);
      };
      addIfExists(propImpl->getGetterMethodDecl());
      addIfExists(propImpl->getSetterMethodDecl());
    }

  if (InstanceMethods.size() == 0)
9
←
Assuming the condition is false→
10
←
Taking false branch→
    classFields.addNullPointer(PtrTy);
  else
    classFields.addBitCast(
            GenerateMethodList(className, "", InstanceMethods, false),
            PtrTy);
  // void *dtable;
  classFields.addNullPointer(PtrTy);
  // IMP cxx_construct;
  classFields.addNullPointer(PtrTy);
  // IMP cxx_destruct;
  classFields.addNullPointer(PtrTy);
  // struct objc_class *subclass_list
  classFields.addNullPointer(PtrTy);
  // struct objc_class *sibling_class
  classFields.addNullPointer(PtrTy);
  // struct objc_protocol_list *protocols;
  auto RuntimeProtocols = GetRuntimeProtocolList(classDecl->protocol_begin(),
                                                 classDecl->protocol_end());
  SmallVector<llvm::Constant *, 16> Protocols;
  for (const auto *I : RuntimeProtocols)
    Protocols.push_back(
        llvm::ConstantExpr::getBitCast(GenerateProtocolRef(I),
          ProtocolPtrTy));
  if (Protocols.empty())
11
←
Taking false branch→
    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));

  llvm::GlobalVariable *classStruct =
    classFields.finishAndCreateGlobal(SymbolForClass(className),
      CGM.getPointerAlign(), false, llvm::GlobalValue::ExternalLinkage);

  auto *classRefSymbol = GetClassVar(className);
12
←
Calling 'CGObjCGNUstep2::GetClassVar'→
  classRefSymbol->setSection(sectionName<ClassReferenceSection>());
  classRefSymbol->setInitializer(llvm::ConstantExpr::getBitCast(classStruct, IdTy));

  if (IsCOFF) {
    // we can't import a class struct.
    if (OID->getClassInterface()->hasAttr<DLLExportAttr>()) {
      classStruct->setDLLStorageClass(llvm::GlobalValue::DLLExportStorageClass);
      cast<llvm::GlobalValue>(classRefSymbol)->setDLLStorageClass(llvm::GlobalValue::DLLExportStorageClass);
    }

    if (SuperClass) {
      std::pair<llvm::GlobalVariable*, int> v{classStruct, 1};
      EarlyInitList.emplace_back(std::string(SuperClass->getName()),
                                 std::move(v));
    }

  }


  // Resolve the class aliases, if they exist.
  // FIXME: Class pointer aliases shouldn't exist!
  if (ClassPtrAlias) {
    ClassPtrAlias->replaceAllUsesWith(
        llvm::ConstantExpr::getBitCast(classStruct, IdTy));
    ClassPtrAlias->eraseFromParent();
    ClassPtrAlias = nullptr;
  }
  if (auto Placeholder =
      TheModule.getNamedGlobal(SymbolForClass(className)))
    if (Placeholder != classStruct) {
      Placeholder->replaceAllUsesWith(
          llvm::ConstantExpr::getBitCast(classStruct, Placeholder->getType()));
      Placeholder->eraseFromParent();
      classStruct->setName(SymbolForClass(className));
    }
  if (MetaClassPtrAlias) {
    MetaClassPtrAlias->replaceAllUsesWith(
        llvm::ConstantExpr::getBitCast(metaclass, IdTy));
    MetaClassPtrAlias->eraseFromParent();
    MetaClassPtrAlias = nullptr;
  }
  assert(classStruct->getName() == SymbolForClass(className))((void)0);

  auto classInitRef = new llvm::GlobalVariable(TheModule,
      classStruct->getType(), false, llvm::GlobalValue::ExternalLinkage,
      classStruct, ManglePublicSymbol("OBJC_INIT_CLASS_") + className);
  classInitRef->setSection(sectionName<ClassSection>());
  CGM.addUsedGlobal(classInitRef);

  EmittedClass = true;
}
public:
  CGObjCGNUstep2(CodeGenModule &Mod) : CGObjCGNUstep(Mod, 10, 4, 2) {
    MsgLookupSuperFn.init(&CGM, "objc_msg_lookup_super", IMPTy,
                          PtrToObjCSuperTy, SelectorTy);
    // struct objc_property
    // {
    //   const char *name;
    //   const char *attributes;
    //   const char *type;
    //   SEL getter;
    //   SEL setter;
    // }
    PropertyMetadataTy =
      llvm::StructType::get(CGM.getLLVMContext(),
          { PtrToInt8Ty, PtrToInt8Ty, PtrToInt8Ty, PtrToInt8Ty, PtrToInt8Ty });
  }

2016};

2018const char *const CGObjCGNUstep2::SectionsBaseNames[8] =
2019{
2020"__objc_selectors",
2021"__objc_classes",
2022"__objc_class_refs",
2023"__objc_cats",
2024"__objc_protocols",
2025"__objc_protocol_refs",
2026"__objc_class_aliases",
2027"__objc_constant_string"
2028};

2030const char *const CGObjCGNUstep2::PECOFFSectionsBaseNames[8] =
2031{
2032".objcrt$SEL",
2033".objcrt$CLS",
2034".objcrt$CLR",
2035".objcrt$CAT",
2036".objcrt$PCL",
2037".objcrt$PCR",
2038".objcrt$CAL",
2039".objcrt$STR"
2040};

2042/// Support for the ObjFW runtime.
2043class CGObjCObjFW: public CGObjCGNU {
2044protected:
/// The GCC ABI message lookup function.  Returns an IMP pointing to the
/// method implementation for this message.
LazyRuntimeFunction MsgLookupFn;
/// stret lookup function.  While this does not seem to make sense at the
/// first look, this is required to call the correct forwarding function.
LazyRuntimeFunction MsgLookupFnSRet;
/// The GCC ABI superclass message lookup function.  Takes a pointer to a
/// structure describing the receiver and the class, and a selector as
/// arguments.  Returns the IMP for the corresponding method.
LazyRuntimeFunction MsgLookupSuperFn, MsgLookupSuperFnSRet;

llvm::Value *LookupIMP(CodeGenFunction &CGF, llvm::Value *&Receiver,
                       llvm::Value *cmd, llvm::MDNode *node,
                       MessageSendInfo &MSI) override {
  CGBuilderTy &Builder = CGF.Builder;
  llvm::Value *args[] = {
          EnforceType(Builder, Receiver, IdTy),
          EnforceType(Builder, cmd, SelectorTy) };

  llvm::CallBase *imp;
  if (CGM.ReturnTypeUsesSRet(MSI.CallInfo))
    imp = CGF.EmitRuntimeCallOrInvoke(MsgLookupFnSRet, args);
  else
    imp = CGF.EmitRuntimeCallOrInvoke(MsgLookupFn, args);

  imp->setMetadata(msgSendMDKind, node);
  return imp;
}

llvm::Value *LookupIMPSuper(CodeGenFunction &CGF, Address ObjCSuper,
                            llvm::Value *cmd, MessageSendInfo &MSI) override {
  CGBuilderTy &Builder = CGF.Builder;
  llvm::Value *lookupArgs[] = {
      EnforceType(Builder, ObjCSuper.getPointer(), PtrToObjCSuperTy), cmd,
  };

  if (CGM.ReturnTypeUsesSRet(MSI.CallInfo))
    return CGF.EmitNounwindRuntimeCall(MsgLookupSuperFnSRet, lookupArgs);
  else
    return CGF.EmitNounwindRuntimeCall(MsgLookupSuperFn, lookupArgs);
}

llvm::Value *GetClassNamed(CodeGenFunction &CGF, const std::string &Name,
                           bool isWeak) override {
  if (isWeak)
    return CGObjCGNU::GetClassNamed(CGF, Name, isWeak);

  EmitClassRef(Name);
  std::string SymbolName = "_OBJC_CLASS_" + Name;
  llvm::GlobalVariable *ClassSymbol = TheModule.getGlobalVariable(SymbolName);
  if (!ClassSymbol)
    ClassSymbol = new llvm::GlobalVariable(TheModule, LongTy, false,
                                           llvm::GlobalValue::ExternalLinkage,
                                           nullptr, SymbolName);
  return ClassSymbol;
}

2102public:
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);
}
2114};
2115} // end anonymous namespace

2117/// Emits a reference to a dummy variable which is emitted with each class.
2118/// This ensures that a linker error will be generated when trying to link
2119/// together modules where a referenced class is not defined.
2120void 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);
2134}

2136CGObjCGNU::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);
}
2285}

2287llvm::Value *CGObjCGNU::GetClassNamed(CodeGenFunction &CGF,
                                    const std::string &Name, bool isWeak) {
llvm::Constant *ClassName = MakeConstantString(Name);
// With the incompatible ABI, this will need to be replaced with a direct
// reference to the class symbol.  For the compatible nonfragile ABI we are
// still performing this lookup at run time but emitting the symbol for the
// class externally so that we can make the switch later.
//
// Libobjc2 contains an LLVM pass that replaces calls to objc_lookup_class
// with memoized versions or with static references if it's safe to do so.
if (!isWeak)
  EmitClassRef(Name);

llvm::FunctionCallee ClassLookupFn = CGM.CreateRuntimeFunction(
    llvm::FunctionType::get(IdTy, PtrToInt8Ty, true), "objc_lookup_class");
return CGF.EmitNounwindRuntimeCall(ClassLookupFn, ClassName);
2303}

2305// This has to perform the lookup every time, since posing and related
2306// techniques can modify the name -> class mapping.
2307llvm::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;
2314}

2316llvm::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;
2333}

2335llvm::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;
2355}

2357Address 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;
2366}

2368llvm::Value *CGObjCGNU::GetSelector(CodeGenFunction &CGF, Selector Sel) {
return GetTypedSelector(CGF, Sel, std::string());
2370}

2372llvm::Value *CGObjCGNU::GetSelector(CodeGenFunction &CGF,
                                  const ObjCMethodDecl *Method) {
std::string SelTypes = CGM.getContext().getObjCEncodingForMethodDecl(Method);
return GetTypedSelector(CGF, Method->getSelector(), SelTypes);
2376}

2378llvm::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.")((void)0);
const ObjCInterfaceDecl *IDecl = OPT->getObjectType()->getInterface();
assert(IDecl && "Invalid @catch type.")((void)0);
return MakeConstantString(IDecl->getIdentifier()->getName());
2397}

2399llvm::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.")((void)0);
const ObjCInterfaceType *IT = PT->getInterfaceType();
assert(IT && "Invalid @catch type.")((void)0);
std::string className =
    std::string(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);
2468}

2470/// Generate an NSConstantString object.
2471ConstantAddress 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);
2507}

2509///Generates a message send where the super is the receiver.  This is a message
2510///send to self with special delivery semantics indicating which class's method
2511///should be called.
2512RValue
2513CGObjCGNU::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(IdTy, ReceiverClass, CGF.getPointerAlign());
  }
  ReceiverClass = EnforceType(Builder, ReceiverClass, IdTy);
} else {
  if (isCategoryImpl) {
    llvm::FunctionCallee 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(IdTy, 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));
Builder.CreateStore(ReceiverClass, Builder.CreateStructGEP(ObjCSuper, 1));

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::CallBase *call;
RValue msgRet = CGF.EmitCall(MSI.CallInfo, callee, Return, ActualArgs, &call);
call->setMetadata(msgSendMDKind, node);
return msgRet;
2629}

2631/// Generate code for a message send expression.
2632RValue
2633CGObjCGNU::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")
              .getCallee();
    } 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")
              .getCallee();
    } else {
      imp = CGM.CreateRuntimeFunction(
                   llvm::FunctionType::get(IdTy, IdTy, true), "objc_msgSend")
                .getCallee();
    }
}

// Reset the receiver in case the lookup modified it
ActualArgs[0] = CallArg(RValue::get(Receiver), ASTIdTy);

imp = EnforceType(Builder, imp, MSI.MessengerType);

llvm::CallBase *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;
2781}

2783/// Generates a MethodList.  Used in construction of a objc_class and
2784/// objc_category structures.
2785llvm::Constant *CGObjCGNU::
2786GenerateMethodList(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(getSymbolNameForMethod(OMD));
  assert(FnPtr && "Can't generate metadata for method that doesn't exist")((void)0);
  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());
2850}

2852/// Generates an IvarList.  Used in construction of a objc_class.
2853llvm::Constant *CGObjCGNU::
2854GenerateIvarList(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());
2886}

2888/// Generate a class structure
2889llvm::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;
2999}

3001llvm::Constant *CGObjCGNU::
3002GenerateProtocolMethodList(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());
3020}

3022// Create the protocol list structure used in classes, categories and so on
3023llvm::Constant *
3024CGObjCGNU::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());
3047}

3049llvm::Value *CGObjCGNU::GenerateProtocolRef(CodeGenFunction &CGF,
                                          const ObjCProtocolDecl *PD) {
auto protocol = GenerateProtocolRef(PD);
llvm::Type *T =
    CGM.getTypes().ConvertType(CGM.getContext().getObjCProtoType());
return CGF.Builder.CreateBitCast(protocol, llvm::PointerType::getUnqual(T));
3055}

3057llvm::Constant *CGObjCGNU::GenerateProtocolRef(const ObjCProtocolDecl *PD) {
llvm::Constant *&protocol = ExistingProtocols[PD->getNameAsString()];
if (!protocol)
  GenerateProtocol(PD);
assert(protocol && "Unknown protocol")((void)0);
return protocol;
3063}

3065llvm::Constant *
3066CGObjCGNU::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());
3090}

3092void CGObjCGNU::GenerateProtocol(const ObjCProtocolDecl *PD) {
if (PD->isNonRuntimeProtocol())
  return;

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);
3163}
3164void 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));
3199}

3201/// Libobjc2 uses a bitfield representation where small(ish) bitfields are
3202/// stored in a 64-bit value with the low bit set to 1 and the remaining 63
3203/// bits set to their values, LSB first, while larger ones are stored in a
3204/// structure of this / form:
3205///
3206/// struct { int32_t length; int32_t values[length]; };
3207///
3208/// The values in the array are stored in host-endian format, with the least
3209/// significant bit being assumed to come first in the bitfield.  Therefore, a
3210/// bitfield with the 64th bit set will be (int64_t)&{ 2, [0, 1<<31] }, while a
3211/// bitfield / with the 63rd bit set will be 1<<64.
3212llvm::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;
3244}

3246llvm::Constant *CGObjCGNU::GenerateCategoryProtocolList(const
  ObjCCategoryDecl *OCD) {
const auto &RefPro = OCD->getReferencedProtocols();
const auto RuntimeProtos =
    GetRuntimeProtocolList(RefPro.begin(), RefPro.end());
SmallVector<std::string, 16> Protocols;
for (const auto *PD : RuntimeProtos)
  Protocols.push_back(PD->getNameAsString());
return GenerateProtocolList(Protocols);
3255}

3257void 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
const ObjCCategoryDecl *CatDecl = OCD->getCategoryDecl();

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(GenerateCategoryProtocolList(CatDecl), 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));
3305}

3307llvm::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());
3394}

3396void 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());
3402}

3404void 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());

llvm::Constant *Properties = GeneratePropertyList(OID, ClassDecl);

// Collect the names of referenced protocols
auto RefProtocols = ClassDecl->protocols();
auto RuntimeProtocols =
    GetRuntimeProtocolList(RefProtocols.begin(), RefProtocols.end());
SmallVector<std::string, 16> Protocols;
for (const auto *I : RuntimeProtocols)
  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);
3622}

3624llvm::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
  std::vector<Selector> allSelectors;
  for (auto &entry : table)
    allSelectors.push_back(entry.first);
  llvm::sort(allSelectors);

  for (auto &untypedSel : allSelectors) {
    std::string selNameStr = untypedSel.getAsString();
    llvm::Constant *selName = ExportUniqueString(selNameStr, ".objc_sel_name");

    for (TypedSelector &sel : table[untypedSel]) {
      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::FunctionCallee 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;
3870}

3872llvm::Function *CGObjCGNU::GenerateMethod(const ObjCMethodDecl *OMD,
                                        const ObjCContainerDecl *CD) {
CodeGenTypes &Types = CGM.getTypes();
llvm::FunctionType *MethodTy =
  Types.GetFunctionType(Types.arrangeObjCMethodDeclaration(OMD));
std::string FunctionName = getSymbolNameForMethod(OMD);

llvm::Function *Method
  = llvm::Function::Create(MethodTy,
                           llvm::GlobalValue::InternalLinkage,
                           FunctionName,
                           &TheModule);
return Method;
3885}

3887void CGObjCGNU::GenerateDirectMethodPrologue(CodeGenFunction &CGF,
                                           llvm::Function *Fn,
                                           const ObjCMethodDecl *OMD,
                                           const ObjCContainerDecl *CD) {
// GNU runtime doesn't support direct calls at this time
3892}

3894llvm::FunctionCallee CGObjCGNU::GetPropertyGetFunction() {
return GetPropertyFn;
3896}

3898llvm::FunctionCallee CGObjCGNU::GetPropertySetFunction() {
return SetPropertyFn;
3900}

3902llvm::FunctionCallee CGObjCGNU::GetOptimizedPropertySetFunction(bool atomic,
                                                              bool copy) {
return nullptr;
3905}

3907llvm::FunctionCallee CGObjCGNU::GetGetStructFunction() {
return GetStructPropertyFn;
3909}

3911llvm::FunctionCallee CGObjCGNU::GetSetStructFunction() {
return SetStructPropertyFn;
3913}

3915llvm::FunctionCallee CGObjCGNU::GetCppAtomicObjectGetFunction() {
return nullptr;
3917}

3919llvm::FunctionCallee CGObjCGNU::GetCppAtomicObjectSetFunction() {
return nullptr;
3921}

3923llvm::FunctionCallee CGObjCGNU::EnumerationMutationFunction() {
return EnumerationMutationFn;
3925}

3927void CGObjCGNU::EmitSynchronizedStmt(CodeGenFunction &CGF,
                                   const ObjCAtSynchronizedStmt &S) {
EmitAtSynchronizedStmt(CGF, S, SyncEnterFn, SyncExitFn);
3930}


3933void 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);
3947}

3949void 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()) &&((void)0)
         "Unexpected rethrow outside @catch block.")((void)0);
  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.
  llvm::CallBase *Throw = CGF.EmitRuntimeCallOrInvoke(ExceptionReThrowFn);
  Throw->setDoesNotReturn();
}
else {
  ExceptionAsObject = CGF.Builder.CreateBitCast(ExceptionAsObject, IdTy);
  llvm::CallBase *Throw =
      CGF.EmitRuntimeCallOrInvoke(ExceptionThrowFn, ExceptionAsObject);
  Throw->setDoesNotReturn();
}
CGF.Builder.CreateUnreachable();
if (ClearInsertionPoint)
  CGF.Builder.ClearInsertionPoint();
3984}

3986llvm::Value * CGObjCGNU::EmitObjCWeakRead(CodeGenFunction &CGF,
                                        Address AddrWeakObj) {
CGBuilderTy &B = CGF.Builder;
AddrWeakObj = EnforceType(B, AddrWeakObj, PtrToIdTy);
return B.CreateCall(WeakReadFn, AddrWeakObj.getPointer());
3991}

3993void 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, {src, dst.getPointer()});
3999}

4001void 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")((void)0);
B.CreateCall(GlobalAssignFn, {src, dst.getPointer()});
4010}

4012void 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, {src, dst.getPointer(), ivarOffset});
4019}

4021void 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, {src, dst.getPointer()});
4027}

4029void 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, {DestPtr.getPointer(), SrcPtr.getPointer(), Size});
4038}

4040llvm::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;
4053}

4055LValue CGObjCGNU::EmitObjCValueForIvar(CodeGenFunction &CGF,
                                     QualType ObjectTy,
                                     llvm::Value *BaseValue,
                                     const ObjCIvarDecl *Ivar,
                                     unsigned CVRQualifiers) {
const ObjCInterfaceDecl *ID =
  ObjectTy->castAs<ObjCObjectType>()->getInterface();
return EmitValueForIvarAtOffset(CGF, ID, BaseValue, Ivar, CVRQualifiers,
                                EmitIvarOffset(CGF, ID, Ivar));
4064}

4066static 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;
4080}

4082llvm::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(
                         llvm::Type::getInt32PtrTy(VMContext),
                         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.getAsAlign());
    Offset = GV;
  }
  Offset = CGF.Builder.CreateAlignedLoad(IntTy, 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);
4119}

4121CGObjCRuntime *
4122clang::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")__builtin_unreachable();
}
llvm_unreachable("bad runtime")__builtin_unreachable();
4143}

←

/usr/src/gnu/usr.bin/clang/libclangCodeGen/../../../llvm/llvm/include/llvm/ADT/Triple.h

1//===-- llvm/ADT/Triple.h - Target triple helper class ----------*- C++ -*-===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//

9#ifndef LLVM_ADT_TRIPLE_H
10#define LLVM_ADT_TRIPLE_H

12#include "llvm/ADT/Twine.h"

14// Some system headers or GCC predefined macros conflict with identifiers in
15// this file.  Undefine them here.
16#undef NetBSD
17#undef mips
18#undef sparc

20namespace llvm {

22class VersionTuple;

24/// Triple - Helper class for working with autoconf configuration names. For
25/// historical reasons, we also call these 'triples' (they used to contain
26/// exactly three fields).
27///
28/// Configuration names are strings in the canonical form:
29///   ARCHITECTURE-VENDOR-OPERATING_SYSTEM
30/// or
31///   ARCHITECTURE-VENDOR-OPERATING_SYSTEM-ENVIRONMENT
32///
33/// This class is used for clients which want to support arbitrary
34/// configuration names, but also want to implement certain special
35/// behavior for particular configurations. This class isolates the mapping
36/// from the components of the configuration name to well known IDs.
37///
38/// At its core the Triple class is designed to be a wrapper for a triple
39/// string; the constructor does not change or normalize the triple string.
40/// Clients that need to handle the non-canonical triples that users often
41/// specify should use the normalize method.
42///
43/// See autoconf/config.guess for a glimpse into what configuration names
44/// look like in practice.
45class Triple {
46public:
enum ArchType {
  UnknownArch,

  arm,            // ARM (little endian): arm, armv.*, xscale
  armeb,          // ARM (big endian): armeb
  aarch64,        // AArch64 (little endian): aarch64
  aarch64_be,     // AArch64 (big endian): aarch64_be
  aarch64_32,     // AArch64 (little endian) ILP32: aarch64_32
  arc,            // ARC: Synopsys ARC
  avr,            // AVR: Atmel AVR microcontroller
  bpfel,          // eBPF or extended BPF or 64-bit BPF (little endian)
  bpfeb,          // eBPF or extended BPF or 64-bit BPF (big endian)
  csky,           // CSKY: csky
  hexagon,        // Hexagon: hexagon
  m68k,           // M68k: Motorola 680x0 family
  mips,           // MIPS: mips, mipsallegrex, mipsr6
  mipsel,         // MIPSEL: mipsel, mipsallegrexe, mipsr6el
  mips64,         // MIPS64: mips64, mips64r6, mipsn32, mipsn32r6
  mips64el,       // MIPS64EL: mips64el, mips64r6el, mipsn32el, mipsn32r6el
  msp430,         // MSP430: msp430
  ppc,            // PPC: powerpc
  ppcle,          // PPCLE: powerpc (little endian)
  ppc64,          // PPC64: powerpc64, ppu
  ppc64le,        // PPC64LE: powerpc64le
  r600,           // R600: AMD GPUs HD2XXX - HD6XXX
  amdgcn,         // AMDGCN: AMD GCN GPUs
  riscv32,        // RISC-V (32-bit): riscv32
  riscv64,        // RISC-V (64-bit): riscv64
  sparc,          // Sparc: sparc
  sparcv9,        // Sparcv9: Sparcv9
  sparcel,        // Sparc: (endianness = little). NB: 'Sparcle' is a CPU variant
  systemz,        // SystemZ: s390x
  tce,            // TCE (http://tce.cs.tut.fi/): tce
  tcele,          // TCE little endian (http://tce.cs.tut.fi/): tcele
  thumb,          // Thumb (little endian): thumb, thumbv.*
  thumbeb,        // Thumb (big endian): thumbeb
  x86,            // X86: i[3-9]86
  x86_64,         // X86-64: amd64, x86_64
  xcore,          // XCore: xcore
  nvptx,          // NVPTX: 32-bit
  nvptx64,        // NVPTX: 64-bit
  le32,           // le32: generic little-endian 32-bit CPU (PNaCl)
  le64,           // le64: generic little-endian 64-bit CPU (PNaCl)
  amdil,          // AMDIL
  amdil64,        // AMDIL with 64-bit pointers
  hsail,          // AMD HSAIL
  hsail64,        // AMD HSAIL with 64-bit pointers
  spir,           // SPIR: standard portable IR for OpenCL 32-bit version
  spir64,         // SPIR: standard portable IR for OpenCL 64-bit version
  kalimba,        // Kalimba: generic kalimba
  shave,          // SHAVE: Movidius vector VLIW processors
  lanai,          // Lanai: Lanai 32-bit
  wasm32,         // WebAssembly with 32-bit pointers
  wasm64,         // WebAssembly with 64-bit pointers
  renderscript32, // 32-bit RenderScript
  renderscript64, // 64-bit RenderScript
  ve,             // NEC SX-Aurora Vector Engine
  LastArchType = ve
};
enum SubArchType {
  NoSubArch,

  ARMSubArch_v8_7a,
  ARMSubArch_v8_6a,
  ARMSubArch_v8_5a,
  ARMSubArch_v8_4a,
  ARMSubArch_v8_3a,
  ARMSubArch_v8_2a,
  ARMSubArch_v8_1a,
  ARMSubArch_v8,
  ARMSubArch_v8r,
  ARMSubArch_v8m_baseline,
  ARMSubArch_v8m_mainline,
  ARMSubArch_v8_1m_mainline,
  ARMSubArch_v7,
  ARMSubArch_v7em,
  ARMSubArch_v7m,
  ARMSubArch_v7s,
  ARMSubArch_v7k,
  ARMSubArch_v7ve,
  ARMSubArch_v6,
  ARMSubArch_v6m,
  ARMSubArch_v6k,
  ARMSubArch_v6t2,
  ARMSubArch_v5,
  ARMSubArch_v5te,
  ARMSubArch_v4t,

  AArch64SubArch_arm64e,

  KalimbaSubArch_v3,
  KalimbaSubArch_v4,
  KalimbaSubArch_v5,

  MipsSubArch_r6,

  PPCSubArch_spe
};
enum VendorType {
  UnknownVendor,

  Apple,
  PC,
  SCEI,
  Freescale,
  IBM,
  ImaginationTechnologies,
  MipsTechnologies,
  NVIDIA,
  CSR,
  Myriad,
  AMD,
  Mesa,
  SUSE,
  OpenEmbedded,
  LastVendorType = OpenEmbedded
};
enum OSType {
  UnknownOS,

  Ananas,
  CloudABI,
  Darwin,
  DragonFly,
  FreeBSD,
  Fuchsia,
  IOS,
  KFreeBSD,
  Linux,
  Lv2,        // PS3
  MacOSX,
  NetBSD,
  OpenBSD,
  Solaris,
  Win32,
  ZOS,
  Haiku,
  Minix,
  RTEMS,
  NaCl,       // Native Client
  AIX,
  CUDA,       // NVIDIA CUDA
  NVCL,       // NVIDIA OpenCL
  AMDHSA,     // AMD HSA Runtime
  PS4,
  ELFIAMCU,
  TvOS,       // Apple tvOS
  WatchOS,    // Apple watchOS
  Mesa3D,
  Contiki,
  AMDPAL,     // AMD PAL Runtime
  HermitCore, // HermitCore Unikernel/Multikernel
  Hurd,       // GNU/Hurd
  WASI,       // Experimental WebAssembly OS
  Emscripten,
  LastOSType = Emscripten
};
enum EnvironmentType {
  UnknownEnvironment,

  GNU,
  GNUABIN32,
  GNUABI64,
  GNUEABI,
  GNUEABIHF,
  GNUX32,
  GNUILP32,
  CODE16,
  EABI,
  EABIHF,
  Android,
  Musl,
  MuslEABI,
  MuslEABIHF,
  MuslX32,

  MSVC,
  Itanium,
  Cygnus,
  CoreCLR,
  Simulator, // Simulator variants of other systems, e.g., Apple's iOS
  MacABI, // Mac Catalyst variant of Apple's iOS deployment target.
  LastEnvironmentType = MacABI
};
enum ObjectFormatType {
  UnknownObjectFormat,

  COFF,
  ELF,
  GOFF,
  MachO,
  Wasm,
  XCOFF,
};

242private:
std::string Data;

/// The parsed arch type.
ArchType Arch;

/// The parsed subarchitecture type.
SubArchType SubArch;

/// The parsed vendor type.
VendorType Vendor;

/// The parsed OS type.
OSType OS;

/// The parsed Environment type.
EnvironmentType Environment;

/// The object format type.
ObjectFormatType ObjectFormat;

263public:
/// @name Constructors
/// @{

/// Default constructor is the same as an empty string and leaves all
/// triple fields unknown.
Triple()
    : Data(), Arch(), SubArch(), Vendor(), OS(), Environment(),
      ObjectFormat() {}

explicit Triple(const Twine &Str);
Triple(const Twine &ArchStr, const Twine &VendorStr, const Twine &OSStr);
Triple(const Twine &ArchStr, const Twine &VendorStr, const Twine &OSStr,
       const Twine &EnvironmentStr);

bool operator==(const Triple &Other) const {
  return Arch == Other.Arch && SubArch == Other.SubArch &&
         Vendor == Other.Vendor && OS == Other.OS &&
         Environment == Other.Environment &&
         ObjectFormat == Other.ObjectFormat;
}

bool operator!=(const Triple &Other) const {
  return !(*this == Other);
}

/// @}
/// @name Normalization
/// @{

/// normalize - Turn an arbitrary machine specification into the canonical
/// triple form (or something sensible that the Triple class understands if
/// nothing better can reasonably be done).  In particular, it handles the
/// common case in which otherwise valid components are in the wrong order.
static std::string normalize(StringRef Str);

/// Return the normalized form of this triple's string.
std::string normalize() const { return normalize(Data); }

/// @}
/// @name Typed Component Access
/// @{

/// getArch - Get the parsed architecture type of this triple.
ArchType getArch() const { return Arch; }

/// getSubArch - get the parsed subarchitecture type for this triple.
SubArchType getSubArch() const { return SubArch; }

/// getVendor - Get the parsed vendor type of this triple.
VendorType getVendor() const { return Vendor; }

/// getOS - Get the parsed operating system type of this triple.
OSType getOS() const { return OS; }

/// hasEnvironment - Does this triple have the optional environment
/// (fourth) component?
bool hasEnvironment() const {
  return getEnvironmentName() != "";
}

/// getEnvironment - Get the parsed environment type of this triple.
EnvironmentType getEnvironment() const { return Environment; }

/// Parse the version number from the OS name component of the
/// triple, if present.
///
/// For example, "fooos1.2.3" would return (1, 2, 3).
///
/// If an entry is not defined, it will be returned as 0.
void getEnvironmentVersion(unsigned &Major, unsigned &Minor,
                           unsigned &Micro) const;

/// getFormat - Get the object format for this triple.
ObjectFormatType getObjectFormat() const { return ObjectFormat; }

/// getOSVersion - Parse the version number from the OS name component of the
/// triple, if present.
///
/// For example, "fooos1.2.3" would return (1, 2, 3).
///
/// If an entry is not defined, it will be returned as 0.
void getOSVersion(unsigned &Major, unsigned &Minor, unsigned &Micro) const;

/// getOSMajorVersion - Return just the major version number, this is
/// specialized because it is a common query.
unsigned getOSMajorVersion() const {
  unsigned Maj, Min, Micro;
  getOSVersion(Maj, Min, Micro);
  return Maj;
}

/// getMacOSXVersion - Parse the version number as with getOSVersion and then
/// translate generic "darwin" versions to the corresponding OS X versions.
/// This may also be called with IOS triples but the OS X version number is
/// just set to a constant 10.4.0 in that case.  Returns true if successful.
bool getMacOSXVersion(unsigned &Major, unsigned &Minor,
                      unsigned &Micro) const;

/// getiOSVersion - Parse the version number as with getOSVersion.  This should
/// only be called with IOS or generic triples.
void getiOSVersion(unsigned &Major, unsigned &Minor,
                   unsigned &Micro) const;

/// getWatchOSVersion - Parse the version number as with getOSVersion.  This
/// should only be called with WatchOS or generic triples.
void getWatchOSVersion(unsigned &Major, unsigned &Minor,
                       unsigned &Micro) const;

/// @}
/// @name Direct Component Access
/// @{

const std::string &str() const { return Data; }

const std::string &getTriple() const { return Data; }

/// getArchName - Get the architecture (first) component of the
/// triple.
StringRef getArchName() const;

/// getVendorName - Get the vendor (second) component of the triple.
StringRef getVendorName() const;

/// getOSName - Get the operating system (third) component of the
/// triple.
StringRef getOSName() const;

/// getEnvironmentName - Get the optional environment (fourth)
/// component of the triple, or "" if empty.
StringRef getEnvironmentName() const;

/// getOSAndEnvironmentName - Get the operating system and optional
/// environment components as a single string (separated by a '-'
/// if the environment component is present).
StringRef getOSAndEnvironmentName() const;

/// @}
/// @name Convenience Predicates
/// @{

/// Test whether the architecture is 64-bit
///
/// Note that this tests for 64-bit pointer width, and nothing else. Note
/// that we intentionally expose only three predicates, 64-bit, 32-bit, and
/// 16-bit. The inner details of pointer width for particular architectures
/// is not summed up in the triple, and so only a coarse grained predicate
/// system is provided.
bool isArch64Bit() const;

/// Test whether the architecture is 32-bit
///
/// Note that this tests for 32-bit pointer width, and nothing else.
bool isArch32Bit() const;

/// Test whether the architecture is 16-bit
///
/// Note that this tests for 16-bit pointer width, and nothing else.
bool isArch16Bit() const;

/// isOSVersionLT - Helper function for doing comparisons against version
/// numbers included in the target triple.
bool isOSVersionLT(unsigned Major, unsigned Minor = 0,
                   unsigned Micro = 0) const {
  unsigned LHS[3];
  getOSVersion(LHS[0], LHS[1], LHS[2]);

  if (LHS[0] != Major)
    return LHS[0] < Major;
  if (LHS[1] != Minor)
    return LHS[1] < Minor;
  if (LHS[2] != Micro)
    return LHS[2] < Micro;

  return false;
}

bool isOSVersionLT(const Triple &Other) const {
  unsigned RHS[3];
  Other.getOSVersion(RHS[0], RHS[1], RHS[2]);
  return isOSVersionLT(RHS[0], RHS[1], RHS[2]);
}

/// isMacOSXVersionLT - Comparison function for checking OS X version
/// compatibility, which handles supporting skewed version numbering schemes
/// used by the "darwin" triples.
bool isMacOSXVersionLT(unsigned Major, unsigned Minor = 0,
                       unsigned Micro = 0) const;

/// isMacOSX - Is this a Mac OS X triple. For legacy reasons, we support both
/// "darwin" and "osx" as OS X triples.
bool isMacOSX() const {
  return getOS() == Triple::Darwin || getOS() == Triple::MacOSX;
}

/// Is this an iOS triple.
/// Note: This identifies tvOS as a variant of iOS. If that ever
/// changes, i.e., if the two operating systems diverge or their version
/// numbers get out of sync, that will need to be changed.
/// watchOS has completely different version numbers so it is not included.
bool isiOS() const {
  return getOS() == Triple::IOS || isTvOS();
}

/// Is this an Apple tvOS triple.
bool isTvOS() const {
  return getOS() == Triple::TvOS;
}

/// Is this an Apple watchOS triple.
bool isWatchOS() const {
  return getOS() == Triple::WatchOS;
}

bool isWatchABI() const {
  return getSubArch() == Triple::ARMSubArch_v7k;
}

bool isOSzOS() const { return getOS() == Triple::ZOS; }

/// isOSDarwin - Is this a "Darwin" OS (macOS, iOS, tvOS or watchOS).
bool isOSDarwin() const {
  return isMacOSX() || isiOS() || isWatchOS();
}

bool isSimulatorEnvironment() const {
  return getEnvironment() == Triple::Simulator;
}

bool isMacCatalystEnvironment() const {
  return getEnvironment() == Triple::MacABI;
}

/// Returns true for targets that run on a macOS machine.
bool isTargetMachineMac() const {
  return isMacOSX() || (isOSDarwin() && (isSimulatorEnvironment() ||
                                         isMacCatalystEnvironment()));
}

bool isOSNetBSD() const {
  return getOS() == Triple::NetBSD;
}

bool isOSOpenBSD() const {
  return getOS() == Triple::OpenBSD;
}

bool isOSFreeBSD() const {
  return getOS() == Triple::FreeBSD;
}

bool isOSFuchsia() const {
  return getOS() == Triple::Fuchsia;
}

bool isOSDragonFly() const { return getOS() == Triple::DragonFly; }

bool isOSSolaris() const {
  return getOS() == Triple::Solaris;
}

bool isOSIAMCU() const {
  return getOS() == Triple::ELFIAMCU;
}

bool isOSUnknown() const { return getOS() == Triple::UnknownOS; }

bool isGNUEnvironment() const {
  EnvironmentType Env = getEnvironment();
  return Env == Triple::GNU || Env == Triple::GNUABIN32 ||
         Env == Triple::GNUABI64 || Env == Triple::GNUEABI ||
         Env == Triple::GNUEABIHF || Env == Triple::GNUX32;
}

bool isOSContiki() const {
  return getOS() == Triple::Contiki;
}

/// Tests whether the OS is Haiku.
bool isOSHaiku() const {
  return getOS() == Triple::Haiku;
}

/// Tests whether the OS is Windows.
bool isOSWindows() const {
  return getOS() == Triple::Win32;
}

/// Checks if the environment is MSVC.
bool isKnownWindowsMSVCEnvironment() const {
  return isOSWindows() && getEnvironment() == Triple::MSVC;
}

/// Checks if the environment could be MSVC.
bool isWindowsMSVCEnvironment() const {
  return isKnownWindowsMSVCEnvironment() ||
         (isOSWindows() && getEnvironment() == Triple::UnknownEnvironment);
}

bool isWindowsCoreCLREnvironment() const {
  return isOSWindows() && getEnvironment() == Triple::CoreCLR;
}

bool isWindowsItaniumEnvironment() const {
  return isOSWindows() && getEnvironment() == Triple::Itanium;
}

bool isWindowsCygwinEnvironment() const {
  return isOSWindows() && getEnvironment() == Triple::Cygnus;
}

bool isWindowsGNUEnvironment() const {
  return isOSWindows() && getEnvironment() == Triple::GNU;
}

/// Tests for either Cygwin or MinGW OS
bool isOSCygMing() const {
  return isWindowsCygwinEnvironment() || isWindowsGNUEnvironment();
}

/// Is this a "Windows" OS targeting a "MSVCRT.dll" environment.
bool isOSMSVCRT() const {
  return isWindowsMSVCEnvironment() || isWindowsGNUEnvironment() ||
         isWindowsItaniumEnvironment();
}

/// Tests whether the OS is NaCl (Native Client)
bool isOSNaCl() const {
  return getOS() == Triple::NaCl;
}

/// Tests whether the OS is Linux.
bool isOSLinux() const {
  return getOS() == Triple::Linux;
}

/// Tests whether the OS is kFreeBSD.
bool isOSKFreeBSD() const {
  return getOS() == Triple::KFreeBSD;
}

/// Tests whether the OS is Hurd.
bool isOSHurd() const {
  return getOS() == Triple::Hurd;
}

/// Tests whether the OS is WASI.
bool isOSWASI() const {
  return getOS() == Triple::WASI;
}

/// Tests whether the OS is Emscripten.
bool isOSEmscripten() const {
  return getOS() == Triple::Emscripten;
}

/// Tests whether the OS uses glibc.
bool isOSGlibc() const {
  return (getOS() == Triple::Linux || getOS() == Triple::KFreeBSD ||
          getOS() == Triple::Hurd) &&
         !isAndroid();
}

/// Tests whether the OS is AIX.
bool isOSAIX() const {
  return getOS() == Triple::AIX;
}

/// Tests whether the OS uses the ELF binary format.
bool isOSBinFormatELF() const {
  return getObjectFormat() == Triple::ELF;
}

/// Tests whether the OS uses the COFF binary format.
bool isOSBinFormatCOFF() const {
  return getObjectFormat() == Triple::COFF;
17
←
Returning the value 1, which participates in a condition later→
}

/// Tests whether the OS uses the GOFF binary format.
bool isOSBinFormatGOFF() const { return getObjectFormat() == Triple::GOFF; }

/// Tests whether the environment is MachO.
bool isOSBinFormatMachO() const {
  return getObjectFormat() == Triple::MachO;
}

/// Tests whether the OS uses the Wasm binary format.
bool isOSBinFormatWasm() const {
  return getObjectFormat() == Triple::Wasm;
}

/// Tests whether the OS uses the XCOFF binary format.
bool isOSBinFormatXCOFF() const {
  return getObjectFormat() == Triple::XCOFF;
}

/// Tests whether the target is the PS4 CPU
bool isPS4CPU() const {
  return getArch() == Triple::x86_64 &&
         getVendor() == Triple::SCEI &&
         getOS() == Triple::PS4;
}

/// Tests whether the target is the PS4 platform
bool isPS4() const {
  return getVendor() == Triple::SCEI &&
         getOS() == Triple::PS4;
}

/// Tests whether the target is Android
bool isAndroid() const { return getEnvironment() == Triple::Android; }

bool isAndroidVersionLT(unsigned Major) const {
  assert(isAndroid() && "Not an Android triple!")((void)0);

  unsigned Env[3];
  getEnvironmentVersion(Env[0], Env[1], Env[2]);

  // 64-bit targets did not exist before API level 21 (Lollipop).
  if (isArch64Bit() && Env[0] < 21)
    Env[0] = 21;

  return Env[0] < Major;
}

/// Tests whether the environment is musl-libc
bool isMusl() const {
  return getEnvironment() == Triple::Musl ||
         getEnvironment() == Triple::MuslEABI ||
         getEnvironment() == Triple::MuslEABIHF ||
         getEnvironment() == Triple::MuslX32;
}

/// Tests whether the target is SPIR (32- or 64-bit).
bool isSPIR() const {
  return getArch() == Triple::spir || getArch() == Triple::spir64;
}

/// Tests whether the target is NVPTX (32- or 64-bit).
bool isNVPTX() const {
  return getArch() == Triple::nvptx || getArch() == Triple::nvptx64;
}

/// Tests whether the target is AMDGCN
bool isAMDGCN() const { return getArch() == Triple::amdgcn; }

bool isAMDGPU() const {
  return getArch() == Triple::r600 || getArch() == Triple::amdgcn;
}

/// Tests whether the target is Thumb (little and big endian).
bool isThumb() const {
  return getArch() == Triple::thumb || getArch() == Triple::thumbeb;
}

/// Tests whether the target is ARM (little and big endian).
bool isARM() const {
  return getArch() == Triple::arm || getArch() == Triple::armeb;
}

/// Tests whether the target is AArch64 (little and big endian).
bool isAArch64() const {
  return getArch() == Triple::aarch64 || getArch() == Triple::aarch64_be ||
         getArch() == Triple::aarch64_32;
}

/// Tests whether the target is AArch64 and pointers are the size specified by
/// \p PointerWidth.
bool isAArch64(int PointerWidth) const {
  assert(PointerWidth == 64 || PointerWidth == 32)((void)0);
  if (!isAArch64())
    return false;
  return getArch() == Triple::aarch64_32 ||
                 getEnvironment() == Triple::GNUILP32
             ? PointerWidth == 32
             : PointerWidth == 64;
}

/// Tests whether the target is MIPS 32-bit (little and big endian).
bool isMIPS32() const {
  return getArch() == Triple::mips || getArch() == Triple::mipsel;
}

/// Tests whether the target is MIPS 64-bit (little and big endian).
bool isMIPS64() const {
  return getArch() == Triple::mips64 || getArch() == Triple::mips64el;
}

/// Tests whether the target is MIPS (little and big endian, 32- or 64-bit).
bool isMIPS() const {
  return isMIPS32() || isMIPS64();
}

/// Tests whether the target is PowerPC (32- or 64-bit LE or BE).
bool isPPC() const {
  return getArch() == Triple::ppc || getArch() == Triple::ppc64 ||
         getArch() == Triple::ppcle || getArch() == Triple::ppc64le;
}

/// Tests whether the target is 32-bit PowerPC (little and big endian).
bool isPPC32() const {
  return getArch() == Triple::ppc || getArch() == Triple::ppcle;
}

/// Tests whether the target is 64-bit PowerPC (little and big endian).
bool isPPC64() const {
  return getArch() == Triple::ppc64 || getArch() == Triple::ppc64le;
}

/// Tests whether the target is RISC-V (32- and 64-bit).
bool isRISCV() const {
  return getArch() == Triple::riscv32 || getArch() == Triple::riscv64;
}

/// Tests whether the target is SystemZ.
bool isSystemZ() const {
  return getArch() == Triple::systemz;
}

/// Tests whether the target is x86 (32- or 64-bit).
bool isX86() const {
  return getArch() == Triple::x86 || getArch() == Triple::x86_64;
}

/// Tests whether the target is VE
bool isVE() const {
  return getArch() == Triple::ve;
}

/// Tests whether the target is wasm (32- and 64-bit).
bool isWasm() const {
  return getArch() == Triple::wasm32 || getArch() == Triple::wasm64;
}

// Tests whether the target is CSKY
bool isCSKY() const {
  return getArch() == Triple::csky;
}

/// Tests whether the target is the Apple "arm64e" AArch64 subarch.
bool isArm64e() const {
  return getArch() == Triple::aarch64 &&
         getSubArch() == Triple::AArch64SubArch_arm64e;
}

/// Tests whether the target is X32.
bool isX32() const {
  EnvironmentType Env = getEnvironment();
  return Env == Triple::GNUX32 || Env == Triple::MuslX32;
}

/// Tests whether the target supports comdat
bool supportsCOMDAT() const {
  return !(isOSBinFormatMachO() || isOSBinFormatXCOFF());
}

/// Tests whether the target uses emulated TLS as default.
bool hasDefaultEmulatedTLS() const {
  return isAndroid() || isOSOpenBSD() || isWindowsCygwinEnvironment();
}

/// Tests whether the target uses -data-sections as default.
bool hasDefaultDataSections() const {
  return isOSBinFormatXCOFF() || isWasm();
}

/// Tests if the environment supports dllimport/export annotations.
bool hasDLLImportExport() const { return isOSWindows() || isPS4CPU(); }

/// @}
/// @name Mutators
/// @{

/// setArch - Set the architecture (first) component of the triple
/// to a known type.
void setArch(ArchType Kind);

/// setVendor - Set the vendor (second) component of the triple to a
/// known type.
void setVendor(VendorType Kind);

/// setOS - Set the operating system (third) component of the triple
/// to a known type.
void setOS(OSType Kind);

/// setEnvironment - Set the environment (fourth) component of the triple
/// to a known type.
void setEnvironment(EnvironmentType Kind);

/// setObjectFormat - Set the object file format
void setObjectFormat(ObjectFormatType Kind);

/// setTriple - Set all components to the new triple \p Str.
void setTriple(const Twine &Str);

/// setArchName - Set the architecture (first) component of the
/// triple by name.
void setArchName(StringRef Str);

/// setVendorName - Set the vendor (second) component of the triple
/// by name.
void setVendorName(StringRef Str);

/// setOSName - Set the operating system (third) component of the
/// triple by name.
void setOSName(StringRef Str);

/// setEnvironmentName - Set the optional environment (fourth)
/// component of the triple by name.
void setEnvironmentName(StringRef Str);

/// setOSAndEnvironmentName - Set the operating system and optional
/// environment components with a single string.
void setOSAndEnvironmentName(StringRef Str);

/// @}
/// @name Helpers to build variants of a particular triple.
/// @{

/// Form a triple with a 32-bit variant of the current architecture.
///
/// This can be used to move across "families" of architectures where useful.
///
/// \returns A new triple with a 32-bit architecture or an unknown
///          architecture if no such variant can be found.
llvm::Triple get32BitArchVariant() const;

/// Form a triple with a 64-bit variant of the current architecture.
///
/// This can be used to move across "families" of architectures where useful.
///
/// \returns A new triple with a 64-bit architecture or an unknown
///          architecture if no such variant can be found.
llvm::Triple get64BitArchVariant() const;

/// Form a triple with a big endian variant of the current architecture.
///
/// This can be used to move across "families" of architectures where useful.
///
/// \returns A new triple with a big endian architecture or an unknown
///          architecture if no such variant can be found.
llvm::Triple getBigEndianArchVariant() const;

/// Form a triple with a little endian variant of the current architecture.
///
/// This can be used to move across "families" of architectures where useful.
///
/// \returns A new triple with a little endian architecture or an unknown
///          architecture if no such variant can be found.
llvm::Triple getLittleEndianArchVariant() const;

/// Get the (LLVM) name of the minimum ARM CPU for the arch we are targeting.
///
/// \param Arch the architecture name (e.g., "armv7s"). If it is an empty
/// string then the triple's arch name is used.
StringRef getARMCPUForArch(StringRef Arch = StringRef()) const;

/// Tests whether the target triple is little endian.
///
/// \returns true if the triple is little endian, false otherwise.
bool isLittleEndian() const;

/// Test whether target triples are compatible.
bool isCompatibleWith(const Triple &Other) const;

/// Merge target triples.
std::string merge(const Triple &Other) const;

/// Some platforms have different minimum supported OS versions that
/// varies by the architecture specified in the triple. This function
/// returns the minimum supported OS version for this triple if one an exists,
/// or an invalid version tuple if this triple doesn't have one.
VersionTuple getMinimumSupportedOSVersion() const;

/// @}
/// @name Static helpers for IDs.
/// @{

/// getArchTypeName - Get the canonical name for the \p Kind architecture.
static StringRef getArchTypeName(ArchType Kind);

/// getArchTypePrefix - Get the "prefix" canonical name for the \p Kind
/// architecture. This is the prefix used by the architecture specific
/// builtins, and is suitable for passing to \see
/// Intrinsic::getIntrinsicForGCCBuiltin().
///
/// \return - The architecture prefix, or 0 if none is defined.
static StringRef getArchTypePrefix(ArchType Kind);

/// getVendorTypeName - Get the canonical name for the \p Kind vendor.
static StringRef getVendorTypeName(VendorType Kind);

/// getOSTypeName - Get the canonical name for the \p Kind operating system.
static StringRef getOSTypeName(OSType Kind);

/// getEnvironmentTypeName - Get the canonical name for the \p Kind
/// environment.
static StringRef getEnvironmentTypeName(EnvironmentType Kind);

/// @}
/// @name Static helpers for converting alternate architecture names.
/// @{

/// getArchTypeForLLVMName - The canonical type for the given LLVM
/// architecture name (e.g., "x86").
static ArchType getArchTypeForLLVMName(StringRef Str);

/// @}

/// Returns a canonicalized OS version number for the specified OS.
static VersionTuple getCanonicalVersionForOS(OSType OSKind,
                                             const VersionTuple &Version);
975};

977} // End llvm namespace


980#endif