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 /// \file
11 /// \brief Defines the Linkage enumeration and various utility 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.
32 ///
33 /// From the language perspective, these entities have external
34 /// linkage. However, since they reside in an anonymous namespace,
35 /// their names are unique to this translation unit, which is
36 /// equivalent to having internal linkage from the code-generation
37 /// point of view.
38 UniqueExternalLinkage,
39
40 /// \brief External linkage, which indicates that the entity can
41 /// be referred to from other translation units.
42 ExternalLinkage
43 };
44
45 /// \brief A more specific kind of linkage than enum Linkage.
46 ///
47 /// This is relevant to CodeGen and AST file reading.
48 enum GVALinkage {
49 GVA_Internal,
50 GVA_C99Inline,
51 GVA_CXXInline,
52 GVA_StrongExternal,
53 GVA_TemplateInstantiation,
54 GVA_ExplicitTemplateInstantiation
55 };
56
57 /// \brief Determine whether the given linkage is semantically external.
isExternalLinkage(Linkage L)58 inline bool isExternalLinkage(Linkage L) {
59 return L == UniqueExternalLinkage || L == ExternalLinkage;
60 }
61
62 /// \brief Compute the minimum linkage given two linages.
minLinkage(Linkage L1,Linkage L2)63 inline Linkage minLinkage(Linkage L1, Linkage L2) {
64 return L1 < L2? L1 : L2;
65 }
66
67 } // end namespace clang
68
69 #endif // LLVM_CLANG_BASIC_LINKAGE_H
70