[modules] When a declaration has non-trivial visibility, check whether it's

actually hidden before we check its linkage. This avoids computing the linkage
"too early" for an anonymous struct with a typedef name for linkage.

llvm-svn: 253012

clang/include/clang/Sema/Lookup.h

@@ -303,8 +303,7 @@ public:
     if (!D->isInIdentifierNamespace(IDNS))
       return nullptr;
 
-    if (!D->isHidden() || isHiddenDeclarationVisible(D) ||
-        isVisibleSlow(getSema(), D))
+    if (isVisible(getSema(), D) || isHiddenDeclarationVisible(D))
       return D;
 
     return getAcceptableDeclSlow(D);

clang/test/Modules/submodule-visibility.cpp

@@ -28,3 +28,10 @@ int k = n + m; // OK, a and b are visible here.
 #ifndef B
 #error B is not defined
 #endif
+
+// Ensure we don't compute the linkage of this struct before we find it has a
+// typedef name for linkage purposes.
+typedef struct {
+  int p;                 
+  void (*f)(int p);                                                                       
+} name_for_linkage;