1 //===-------- llvm/GlobalIFunc.h - GlobalIFunc 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 //===----------------------------------------------------------------------===//
8 ///
9 /// \brief
10 /// This file contains the declaration of the GlobalIFunc class, which
11 /// represents a single indirect function in the IR. Indirect function uses
12 /// ELF symbol type extension to mark that the address of a declaration should
13 /// be resolved at runtime by calling a resolver function.
14 ///
15 //===----------------------------------------------------------------------===//
16 
17 #ifndef LLVM_IR_GLOBALIFUNC_H
18 #define LLVM_IR_GLOBALIFUNC_H
19 
20 #include "llvm/ADT/ilist_node.h"
21 #include "llvm/IR/GlobalIndirectSymbol.h"
22 #include "llvm/IR/Value.h"
23 
24 namespace llvm {
25 
26 class Twine;
27 class Module;
28 
29 // Traits class for using GlobalIFunc in symbol table in Module.
30 template <typename ValueSubClass> class SymbolTableListTraits;
31 
32 class GlobalIFunc final : public GlobalIndirectSymbol,
33                           public ilist_node<GlobalIFunc> {
34   friend class SymbolTableListTraits<GlobalIFunc>;
35 
36   GlobalIFunc(Type *Ty, unsigned AddressSpace, LinkageTypes Linkage,
37               const Twine &Name, Constant *Resolver, Module *Parent);
38 
39 public:
40   GlobalIFunc(const GlobalIFunc &) = delete;
41   GlobalIFunc &operator=(const GlobalIFunc &) = delete;
42 
43   /// If a parent module is specified, the ifunc is automatically inserted into
44   /// the end of the specified module's ifunc list.
45   static GlobalIFunc *create(Type *Ty, unsigned AddressSpace,
46                              LinkageTypes Linkage, const Twine &Name,
47                              Constant *Resolver, Module *Parent);
48 
49   /// This method unlinks 'this' from the containing module, but does not
50   /// delete it.
51   void removeFromParent();
52 
53   /// This method unlinks 'this' from the containing module and deletes it.
54   void eraseFromParent();
55 
56   /// These methods retrieve and set ifunc resolver function.
57   void setResolver(Constant *Resolver) {
58     setIndirectSymbol(Resolver);
59   }
60   const Constant *getResolver() const {
61     return getIndirectSymbol();
62   }
63   Constant *getResolver() {
64     return getIndirectSymbol();
65   }
66 
67   // Methods for support type inquiry through isa, cast, and dyn_cast:
68   static bool classof(const Value *V) {
69     return V->getValueID() == Value::GlobalIFuncVal;
70   }
71 };
72 
73 } // end namespace llvm
74 
75 #endif // LLVM_IR_GLOBALIFUNC_H
76