[AST] Cache intermediate visibility/linkage results

This is a follow-up to r310436 with actual functional changes. Please
see that commit message for a description of why a cache is appearing
here.

Suggestions for less-bad ways of testing this are appreciated. :)

This fixes PR29160.

llvm-svn: 310437

1 files changed, 41 insertions, 0 deletions

diff --git a/clang/test/CodeGenCXX/pr29160.cpp b/clang/test/CodeGenCXX/pr29160.cpp
new file mode 100644
index 00000000000..9c9238e8a0b
--- /dev/null
+++ b/clang/test/CodeGenCXX/pr29160.cpp
@@ -0,0 +1,41 @@
+// RUN: %clang_cc1 -std=c++11 %s -o /dev/null -S
+//
+// This test's failure mode is running ~forever. (For some value of "forever"
+// that's greater than 25 minutes on my machine)
+
+template <typename... Ts>
+struct Foo {
+  template <typename... T>
+  static void ignore() {}
+  Foo() { ignore<Ts...>(); }
+};
+
+struct Base {
+  Base();
+  ~Base();
+};
+
+#define STAMP(thiz, prev) using thiz = Foo< \
+  prev, prev, prev, prev, prev, prev, prev, prev, prev, prev, prev, prev, \
+  prev, prev, prev, prev, prev, prev, prev, prev, prev, prev, prev, prev, \
+  prev, prev, prev, prev, prev, prev, prev, prev, prev, prev, prev, prev \
+  >;
+STAMP(A, Base);
+STAMP(B, A);
+STAMP(C, B);
+STAMP(D, C);
+STAMP(E, D);
+STAMP(F, E);
+STAMP(G, F);
+STAMP(H, G);
+STAMP(I, H);
+STAMP(J, I);
+STAMP(K, J);
+STAMP(L, K);
+STAMP(M, L);
+STAMP(N, M);
+STAMP(O, N);
+STAMP(P, O);
+STAMP(Q, P);
+
+int main() { Q q; }