[PATCH] D44670: [CXX] Templates specialization visibility can be wrong

[Steven Wu via Phabricator via cfe-commits]

steven_wu created this revision.
steven_wu added reviewers: rsmith, arphaman.

Under some conditions, LinkageComputer can get the visibility for
ClassTemplateSpecializationDecl wrong because it failed to find the Decl
that has the explicit visibility.

This fixes:
llvm.org/bugs/pr36810
rdar://problem/38080953


Repository:
  rC Clang

https://reviews.llvm.org/D44670

Files:
  lib/AST/Decl.cpp
  test/CodeGenCXX/visibility-pr36810.cpp


Index: test/CodeGenCXX/visibility-pr36810.cpp
===================================================================
--- /dev/null
+++ test/CodeGenCXX/visibility-pr36810.cpp
@@ -0,0 +1,23 @@
+// RUN: %clang_cc1 -triple x86_64-apple-macosx -std=c++11 -fvisibility hidden -emit-llvm -o - %s -O2 -disable-llvm-passes | FileCheck %s
+// RUN: %clang_cc1 -triple x86_64-apple-macosx -DUNDEF_G -std=c++11 -fvisibility hidden -emit-llvm -o - %s -O2 -disable-llvm-passes | FileCheck %s
+
+namespace std {
+template <class>
+class __attribute__((__type_visibility__("default"))) shared_ptr {
+  template <class> friend class shared_ptr;
+};
+}
+struct dict;
+#ifndef UNDEF_G
+std::shared_ptr<dict> g;
+#endif
+class __attribute__((visibility("default"))) Bar;
+template <class = std::shared_ptr<Bar>>
+class __attribute__((visibility("default"))) i {
+  std::shared_ptr<int> foo() const;
+};
+
+// CHECK: define void @_ZNK1iISt10shared_ptrI3BarEE3fooEv
+template <> std::shared_ptr<int> i<>::foo() const {
+  return std::shared_ptr<int>();
+}
Index: lib/AST/Decl.cpp
===================================================================
--- lib/AST/Decl.cpp
+++ lib/AST/Decl.cpp
@@ -1073,9 +1073,15 @@
   // If there wasn't explicit visibility there, and this is a
   // specialization of a class template, check for visibility
   // on the pattern.
-  if (const auto *spec = dyn_cast<ClassTemplateSpecializationDecl>(ND))
-    return getVisibilityOf(spec->getSpecializedTemplate()->getTemplatedDecl(),
-                           kind);
+  if (const auto *spec = dyn_cast<ClassTemplateSpecializationDecl>(ND)) {
+    for (const auto *RD :
+         spec->getSpecializedTemplate()->getTemplatedDecl()->redecls()) {
+      auto Vis = getVisibilityOf(RD, kind);
+      if (Vis != None)
+        return Vis;
+    }
+    return None;
+  }
 
   // Use the most recent declaration.
   if (!IsMostRecent && !isa<NamespaceDecl>(ND)) {


-------------- next part --------------
A non-text attachment was scrubbed...
Name: D44670.139069.patch
Type: text/x-patch
Size: 1912 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/cfe-commits/attachments/20180320/4a743454/attachment.bin>