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/// \file
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/Constant.h"
22#include "llvm/IR/GlobalObject.h"
23#include "llvm/IR/OperandTraits.h"
24#include "llvm/IR/Value.h"
25
26namespace llvm {
27
28class Twine;
29class Module;
30
31// Traits class for using GlobalIFunc in symbol table in Module.
32template <typename ValueSubClass> class SymbolTableListTraits;
33
34class GlobalIFunc final : public GlobalObject, public ilist_node<GlobalIFunc> {
35 friend class SymbolTableListTraits<GlobalIFunc>;
36
37 GlobalIFunc(Type *Ty, unsigned AddressSpace, LinkageTypes Linkage,
38 const Twine &Name, Constant *Resolver, Module *Parent);
39
40public:
41 GlobalIFunc(const GlobalIFunc &) = delete;
42 GlobalIFunc &operator=(const GlobalIFunc &) = delete;
43
44 /// If a parent module is specified, the ifunc is automatically inserted into
45 /// the end of the specified module's ifunc list.
46 static GlobalIFunc *create(Type *Ty, unsigned AddressSpace,
47 LinkageTypes Linkage, const Twine &Name,
48 Constant *Resolver, Module *Parent);
49
50 // allocate space for exactly one operand
51 void *operator new(size_t S) { return User::operator new(S, 1); }
52 void operator delete(void *Ptr) { User::operator delete(Ptr); }
53
54 /// Provide fast operand accessors
55 DECLARE_TRANSPARENT_OPERAND_ACCESSORS(Constant);
56
57 void copyAttributesFrom(const GlobalIFunc *Src) {
58 GlobalObject::copyAttributesFrom(Src);
59 }
60
61 /// This method unlinks 'this' from the containing module, but does not
62 /// delete it.
63 void removeFromParent();
64
65 /// This method unlinks 'this' from the containing module and deletes it.
66 void eraseFromParent();
67
68 /// These methods retrieve and set ifunc resolver function.
69 void setResolver(Constant *Resolver) { Op<0>().set(Resolver); }
70 const Constant *getResolver() const {
71 return static_cast<Constant *>(Op<0>().get());
72 }
73 Constant *getResolver() { return static_cast<Constant *>(Op<0>().get()); }
74
75 // Return the resolver function after peeling off potential ConstantExpr
76 // indirection.
77 const Function *getResolverFunction() const;
78 Function *getResolverFunction() {
79 return const_cast<Function *>(
80 static_cast<const GlobalIFunc *>(this)->getResolverFunction());
81 }
82
83 static FunctionType *getResolverFunctionType(Type *IFuncValTy) {
84 return FunctionType::get(IFuncValTy->getPointerTo(), false);
85 }
86
87 static bool isValidLinkage(LinkageTypes L) {
88 return isExternalLinkage(L) || isLocalLinkage(L) || isWeakLinkage(L) ||
89 isLinkOnceLinkage(L);
90 }
91
92 // Methods for support type inquiry through isa, cast, and dyn_cast:
93 static bool classof(const Value *V) {
94 return V->getValueID() == Value::GlobalIFuncVal;
95 }
96
97 // Apply specific operation to all resolver-related values. If resolver target
98 // is already a global object, then apply the operation to it directly. If
99 // target is a GlobalExpr or a GlobalAlias, evaluate it to its base object and
100 // apply the operation for the base object and all aliases along the path.
101 void applyAlongResolverPath(function_ref<void(const GlobalValue &)> Op) const;
102};
103
104template <>
105struct OperandTraits<GlobalIFunc>
106 : public FixedNumOperandTraits<GlobalIFunc, 1> {};
107
108DEFINE_TRANSPARENT_OPERAND_ACCESSORS(GlobalIFunc, Constant)
109
110} // end namespace llvm
111
112#endif // LLVM_IR_GLOBALIFUNC_H
113

source code of llvm/include/llvm/IR/GlobalIFunc.h