1 //===--- Linkage.h - Linkage enumeration and utilities ----------*- C++ -*-===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // This file defines the Linkage enumeration and various utility
11 // functions.
12 //
13 //===----------------------------------------------------------------------===//
14 #ifndef LLVM_CLANG_BASIC_LINKAGE_H
15 #define LLVM_CLANG_BASIC_LINKAGE_H
16
17 namespace clang {
18
19 /// \brief Describes the different kinds of linkage
20 /// (C++ [basic.link], C99 6.2.2) that an entity may have.
21 enum Linkage {
22 /// \brief No linkage, which means that the entity is unique and
23 /// can only be referred to from within its scope.
24 NoLinkage = 0,
25
26 /// \brief Internal linkage, which indicates that the entity can
27 /// be referred to from within the translation unit (but not other
28 /// translation units).
29 InternalLinkage,
30
31 /// \brief External linkage within a unique namespace. From the
32 /// language perspective, these entities have external
33 /// linkage. However, since they reside in an anonymous namespace,
34 /// their names are unique to this translation unit, which is
35 /// equivalent to having internal linkage from the code-generation
36 /// point of view.
37 UniqueExternalLinkage,
38
39 /// \brief External linkage, which indicates that the entity can
40 /// be referred to from other translation units.
41 ExternalLinkage
42 };
43
44 /// \brief A more specific kind of linkage. This is relevant to CodeGen and
45 /// AST file reading.
46 enum GVALinkage {
47 GVA_Internal,
48 GVA_C99Inline,
49 GVA_CXXInline,
50 GVA_StrongExternal,
51 GVA_TemplateInstantiation,
52 GVA_ExplicitTemplateInstantiation
53 };
54
55 /// \brief Determine whether the given linkage is semantically
56 /// external.
isExternalLinkage(Linkage L)57 inline bool isExternalLinkage(Linkage L) {
58 return L == UniqueExternalLinkage || L == ExternalLinkage;
59 }
60
61 /// \brief Compute the minimum linkage given two linages.
minLinkage(Linkage L1,Linkage L2)62 static inline Linkage minLinkage(Linkage L1, Linkage L2) {
63 return L1 < L2? L1 : L2;
64 }
65
66 } // end namespace clang
67
68 #endif // LLVM_CLANG_BASIC_LINKAGE_H
69