Substantially revise how clang computes the visibility of a declaration to

more closely parallel the computation of linkage.  This gets us to a state
much closer to what gcc emits, modulo bugs, which will undoubtedly arise in
abundance.



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@117147 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 48 insertions, 0 deletions

diff --git a/include/clang/Basic/Visibility.h b/include/clang/Basic/Visibility.h
new file mode 100644
index 0000000000..90e288a224
--- /dev/null
+++ b/include/clang/Basic/Visibility.h
@@ -0,0 +1,48 @@
+//===--- Visibility.h - Visibility enumeration and utilities ----*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file defines the Visibility enumeration and various utility
+// functions.
+//
+//===----------------------------------------------------------------------===//
+#ifndef LLVM_CLANG_BASIC_VISIBILITY_H
+#define LLVM_CLANG_BASIC_VISIBILITY_H
+
+namespace clang {
+
+/// \link Describes the different kinds of visibility that a
+/// declaration may have.  Visibility determines how a declaration
+/// interacts with the dynamic linker.  It may also affect whether the
+/// symbol can be found by runtime symbol lookup APIs.
+///
+/// Visibility is not described in any language standard and
+/// (nonetheless) sometimes has odd behavior.  Not all platforms
+/// support all visibility kinds.
+enum Visibility {
+  /// Objects with "hidden" visibility are not seen by the dynamic
+  /// linker.
+  HiddenVisibility,
+
+  /// Objects with "protected" visibility are seen by the dynamic
+  /// linker but always dynamically resolve to an object within this
+  /// shared object.
+  ProtectedVisibility,
+
+  /// Objects with "default" visibility are seen by the dynamic linker
+  /// and act like normal objects.
+  DefaultVisibility
+};
+
+inline Visibility minVisibility(Visibility L, Visibility R) {
+  return L < R ? L : R;
+}
+
+}
+
+#endif // LLVM_CLANG_BASIC_VISIBILITY_H