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//===-------- llvm/GlobalIFunc.h - GlobalIFunc class ------------*- C++ -*-===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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///
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/// \file
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/// This file contains the declaration of the GlobalIFunc class, which
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/// represents a single indirect function in the IR. Indirect function uses
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/// ELF symbol type extension to mark that the address of a declaration should
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/// be resolved at runtime by calling a resolver function.
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///
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_IR_GLOBALIFUNC_H
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#define LLVM_IR_GLOBALIFUNC_H
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#include "llvm/ADT/ilist_node.h"
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#include "llvm/IR/Constant.h"
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#include "llvm/IR/GlobalObject.h"
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#include "llvm/IR/OperandTraits.h"
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#include "llvm/IR/Value.h"
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namespace llvm {
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class Twine;
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class Module;
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// Traits class for using GlobalIFunc in symbol table in Module.
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template <typename ValueSubClass> class SymbolTableListTraits;
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class GlobalIFunc final : public GlobalObject, public ilist_node<GlobalIFunc> {
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  friend class SymbolTableListTraits<GlobalIFunc>;
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  GlobalIFunc(Type *Ty, unsigned AddressSpace, LinkageTypes Linkage,
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              const Twine &Name, Constant *Resolver, Module *Parent);
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public:
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  GlobalIFunc(const GlobalIFunc &) = delete;
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  GlobalIFunc &operator=(const GlobalIFunc &) = delete;
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  /// If a parent module is specified, the ifunc is automatically inserted into
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  /// the end of the specified module's ifunc list.
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  static GlobalIFunc *create(Type *Ty, unsigned AddressSpace,
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                             LinkageTypes Linkage, const Twine &Name,
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                             Constant *Resolver, Module *Parent);
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  // allocate space for exactly one operand
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  void *operator new(size_t S) { return User::operator new(S, 1); }
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  void operator delete(void *Ptr) { User::operator delete(Ptr); }
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  /// Provide fast operand accessors
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  DECLARE_TRANSPARENT_OPERAND_ACCESSORS(Constant);
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  void copyAttributesFrom(const GlobalIFunc *Src) {
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    GlobalObject::copyAttributesFrom(Src);
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  }
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  /// This method unlinks 'this' from the containing module, but does not
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  /// delete it.
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  void removeFromParent();
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  /// This method unlinks 'this' from the containing module and deletes it.
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  void eraseFromParent();
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  /// These methods retrieve and set ifunc resolver function.
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  void setResolver(Constant *Resolver) { Op<0>().set(Resolver); }
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  const Constant *getResolver() const {
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    return static_cast<Constant *>(Op<0>().get());
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  }
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  Constant *getResolver() { return static_cast<Constant *>(Op<0>().get()); }
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  // Return the resolver function after peeling off potential ConstantExpr
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  // indirection.
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  const Function *getResolverFunction() const;
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  Function *getResolverFunction() {
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    return const_cast<Function *>(
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        static_cast<const GlobalIFunc *>(this)->getResolverFunction());
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  }
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  static FunctionType *getResolverFunctionType(Type *IFuncValTy) {
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    return FunctionType::get(IFuncValTy->getPointerTo(), false);
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  }
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  static bool isValidLinkage(LinkageTypes L) {
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    return isExternalLinkage(L) || isLocalLinkage(L) || isWeakLinkage(L) ||
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           isLinkOnceLinkage(L);
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  }
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  // Methods for support type inquiry through isa, cast, and dyn_cast:
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  static bool classof(const Value *V) {
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    return V->getValueID() == Value::GlobalIFuncVal;
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  }
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  // Apply specific operation to all resolver-related values. If resolver target
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  // is already a global object, then apply the operation to it directly. If
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  // target is a GlobalExpr or a GlobalAlias, evaluate it to its base object and
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  // apply the operation for the base object and all aliases along the path.
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  void applyAlongResolverPath(function_ref<void(const GlobalValue &)> Op) const;
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};
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template <>
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struct OperandTraits<GlobalIFunc>
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    : public FixedNumOperandTraits<GlobalIFunc, 1> {};
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DEFINE_TRANSPARENT_OPERAND_ACCESSORS(GlobalIFunc, Constant)
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} // end namespace llvm
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#endif // LLVM_IR_GLOBALIFUNC_H