Visibility.h source code [clang_source_code/include/clang/Basic/Visibility.h]

1	//===--- Visibility.h - Visibility enumeration and utilities ----- 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	/// Defines the clang::Visibility enumeration and various utility
11	/// functions.
12	///
13	//===----------------------------------------------------------------------===//
14	#ifndef LLVM_CLANG_BASIC_VISIBILITY_H
15	#define LLVM_CLANG_BASIC_VISIBILITY_H
16
17	#include "clang/Basic/Linkage.h"
18	#include <cassert>
19	#include <cstdint>
20
21	namespace clang {
22
23	/// Describes the different kinds of visibility that a declaration
24	/// may have.
25	///
26	/// Visibility determines how a declaration interacts with the dynamic
27	/// linker. It may also affect whether the symbol can be found by runtime
28	/// symbol lookup APIs.
29	///
30	/// Visibility is not described in any language standard and
31	/// (nonetheless) sometimes has odd behavior. Not all platforms
32	/// support all visibility kinds.
33	enum Visibility {
34	/// Objects with "hidden" visibility are not seen by the dynamic
35	/// linker.
36	HiddenVisibility,
37
38	/// Objects with "protected" visibility are seen by the dynamic
39	/// linker but always dynamically resolve to an object within this
40	/// shared object.
41	ProtectedVisibility,
42
43	/// Objects with "default" visibility are seen by the dynamic linker
44	/// and act like normal objects.
45	DefaultVisibility
46	};
47
48	inline Visibility minVisibility(Visibility L, Visibility R) {
49	return L < R ? L : R;
50	}
51
52	class LinkageInfo {
53	uint8_t linkage_ : 3;
54	uint8_t visibility_ : 2;
55	uint8_t explicit_ : 1;
56
57	void setVisibility(Visibility V, bool E) { visibility_ = V; explicit_ = E; }
58	public:
59	LinkageInfo() : linkage_(ExternalLinkage), visibility_(DefaultVisibility),
60	explicit_(false) {}
61	LinkageInfo(Linkage L, Visibility V, bool E)
62	: linkage_(L), visibility_(V), explicit_(E) {
63	(0) . __assert_fail ("getLinkage() == L && getVisibility() == V && isVisibilityExplicit() == E && \"Enum truncated!\"", "/home/seafit/code_projects/clang_source/clang/include/clang/Basic/Visibility.h", 64, __PRETTY_FUNCTION__))" file_link="../../../../include/assert.h.html#88" macro="true">assert(getLinkage() == L && getVisibility() == V &&
64	(0) . __assert_fail ("getLinkage() == L && getVisibility() == V && isVisibilityExplicit() == E && \"Enum truncated!\"", "/home/seafit/code_projects/clang_source/clang/include/clang/Basic/Visibility.h", 64, __PRETTY_FUNCTION__))" file_link="../../../../include/assert.h.html#88" macro="true"> isVisibilityExplicit() == E && "Enum truncated!");
65	}
66
67	static LinkageInfo external() {
68	return LinkageInfo();
69	}
70	static LinkageInfo internal() {
71	return LinkageInfo(InternalLinkage, DefaultVisibility, false);
72	}
73	static LinkageInfo uniqueExternal() {
74	return LinkageInfo(UniqueExternalLinkage, DefaultVisibility, false);
75	}
76	static LinkageInfo none() {
77	return LinkageInfo(NoLinkage, DefaultVisibility, false);
78	}
79	static LinkageInfo visible_none() {
80	return LinkageInfo(VisibleNoLinkage, DefaultVisibility, false);
81	}
82
83	Linkage getLinkage() const { return (Linkage)linkage_; }
84	Visibility getVisibility() const { return (Visibility)visibility_; }
85	bool isVisibilityExplicit() const { return explicit_; }
86
87	void setLinkage(Linkage L) { linkage_ = L; }
88
89	void mergeLinkage(Linkage L) {
90	setLinkage(minLinkage(getLinkage(), L));
91	}
92	void mergeLinkage(LinkageInfo other) {
93	mergeLinkage(other.getLinkage());
94	}
95
96	void mergeExternalVisibility(Linkage L) {
97	Linkage ThisL = getLinkage();
98	if (!isExternallyVisible(L)) {
99	if (ThisL == VisibleNoLinkage)
100	ThisL = NoLinkage;
101	else if (ThisL == ExternalLinkage)
102	ThisL = UniqueExternalLinkage;
103	}
104	setLinkage(ThisL);
105	}
106	void mergeExternalVisibility(LinkageInfo Other) {
107	mergeExternalVisibility(Other.getLinkage());
108	}
109
110	/// Merge in the visibility 'newVis'.
111	void mergeVisibility(Visibility newVis, bool newExplicit) {
112	Visibility oldVis = getVisibility();
113
114	// Never increase visibility.
115	if (oldVis < newVis)
116	return;
117
118	// If the new visibility is the same as the old and the new
119	// visibility isn't explicit, we have nothing to add.
120	if (oldVis == newVis && !newExplicit)
121	return;
122
123	// Otherwise, we're either decreasing visibility or making our
124	// existing visibility explicit.
125	setVisibility(newVis, newExplicit);
126	}
127	void mergeVisibility(LinkageInfo other) {
128	mergeVisibility(other.getVisibility(), other.isVisibilityExplicit());
129	}
130
131	/// Merge both linkage and visibility.
132	void merge(LinkageInfo other) {
133	mergeLinkage(other);
134	mergeVisibility(other);
135	}
136
137	/// Merge linkage and conditionally merge visibility.
138	void mergeMaybeWithVisibility(LinkageInfo other, bool withVis) {
139	mergeLinkage(other);
140	if (withVis) mergeVisibility(other);
141	}
142	};
143	}
144
145	#endif // LLVM_CLANG_BASIC_VISIBILITY_H
146

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