142 lines
4.2 KiB
C++
142 lines
4.2 KiB
C++
//===--- Visibility.h - Visibility enumeration and utilities ----*- C++ -*-===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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///
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/// \file
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/// \brief Defines the clang::Visibility enumeration and various utility
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/// functions.
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///
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_CLANG_BASIC_VISIBILITY_H
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#define LLVM_CLANG_BASIC_VISIBILITY_H
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#include "clang/Basic/Linkage.h"
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namespace clang {
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/// \brief Describes the different kinds of visibility that a declaration
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/// may have.
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///
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/// Visibility determines how a declaration interacts with the dynamic
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/// linker. It may also affect whether the symbol can be found by runtime
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/// symbol lookup APIs.
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///
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/// Visibility is not described in any language standard and
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/// (nonetheless) sometimes has odd behavior. Not all platforms
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/// support all visibility kinds.
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enum Visibility {
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/// Objects with "hidden" visibility are not seen by the dynamic
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/// linker.
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HiddenVisibility,
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/// Objects with "protected" visibility are seen by the dynamic
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/// linker but always dynamically resolve to an object within this
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/// shared object.
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ProtectedVisibility,
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/// Objects with "default" visibility are seen by the dynamic linker
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/// and act like normal objects.
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DefaultVisibility
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};
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inline Visibility minVisibility(Visibility L, Visibility R) {
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return L < R ? L : R;
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}
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class LinkageInfo {
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uint8_t linkage_ : 3;
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uint8_t visibility_ : 2;
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uint8_t explicit_ : 1;
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void setVisibility(Visibility V, bool E) { visibility_ = V; explicit_ = E; }
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public:
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LinkageInfo() : linkage_(ExternalLinkage), visibility_(DefaultVisibility),
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explicit_(false) {}
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LinkageInfo(Linkage L, Visibility V, bool E)
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: linkage_(L), visibility_(V), explicit_(E) {
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assert(getLinkage() == L && getVisibility() == V &&
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isVisibilityExplicit() == E && "Enum truncated!");
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}
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static LinkageInfo external() {
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return LinkageInfo();
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}
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static LinkageInfo internal() {
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return LinkageInfo(InternalLinkage, DefaultVisibility, false);
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}
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static LinkageInfo uniqueExternal() {
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return LinkageInfo(UniqueExternalLinkage, DefaultVisibility, false);
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}
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static LinkageInfo none() {
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return LinkageInfo(NoLinkage, DefaultVisibility, false);
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}
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Linkage getLinkage() const { return (Linkage)linkage_; }
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Visibility getVisibility() const { return (Visibility)visibility_; }
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bool isVisibilityExplicit() const { return explicit_; }
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void setLinkage(Linkage L) { linkage_ = L; }
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void mergeLinkage(Linkage L) {
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setLinkage(minLinkage(getLinkage(), L));
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}
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void mergeLinkage(LinkageInfo other) {
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mergeLinkage(other.getLinkage());
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}
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void mergeExternalVisibility(Linkage L) {
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Linkage ThisL = getLinkage();
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if (!isExternallyVisible(L)) {
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if (ThisL == VisibleNoLinkage)
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ThisL = NoLinkage;
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else if (ThisL == ExternalLinkage)
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ThisL = UniqueExternalLinkage;
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}
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setLinkage(ThisL);
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}
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void mergeExternalVisibility(LinkageInfo Other) {
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mergeExternalVisibility(Other.getLinkage());
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}
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/// Merge in the visibility 'newVis'.
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void mergeVisibility(Visibility newVis, bool newExplicit) {
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Visibility oldVis = getVisibility();
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// Never increase visibility.
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if (oldVis < newVis)
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return;
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// If the new visibility is the same as the old and the new
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// visibility isn't explicit, we have nothing to add.
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if (oldVis == newVis && !newExplicit)
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return;
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// Otherwise, we're either decreasing visibility or making our
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// existing visibility explicit.
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setVisibility(newVis, newExplicit);
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}
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void mergeVisibility(LinkageInfo other) {
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mergeVisibility(other.getVisibility(), other.isVisibilityExplicit());
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}
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/// Merge both linkage and visibility.
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void merge(LinkageInfo other) {
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mergeLinkage(other);
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mergeVisibility(other);
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}
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/// Merge linkage and conditionally merge visibility.
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void mergeMaybeWithVisibility(LinkageInfo other, bool withVis) {
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mergeLinkage(other);
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if (withVis) mergeVisibility(other);
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}
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};
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}
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#endif // LLVM_CLANG_BASIC_VISIBILITY_H
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