[modules] Fix bug where an anonymous namespace could cause the containing

namespace to not merge properly.

We have an invariant here: after a declaration reads its canonical declaration,
it can assume the canonical declaration is fully merged. This invariant can be
violated if deserializing some declaration triggers the deserialization of a
later declaration, because that later declaration can in turn deserialize a
redeclaration of that first declaration before it is fully merged.

The anonymous namespace for a namespace gets stored with the first declaration
of that namespace, which may be before its parent namespace, so defer loading
it until after we've finished merging the surrounding namespace.

llvm-svn: 232455

6 files changed, 15 insertions, 0 deletions

diff --git a/clang/test/Modules/Inputs/anon-namespace/a.h b/clang/test/Modules/Inputs/anon-namespace/a.h
new file mode 100644
index 00000000000..fe71f4004e4
--- /dev/null
+++ b/clang/test/Modules/Inputs/anon-namespace/a.h
@@ -0,0 +1 @@
+namespace N {}
diff --git a/clang/test/Modules/Inputs/anon-namespace/b1.h b/clang/test/Modules/Inputs/anon-namespace/b1.h
new file mode 100644
index 00000000000..480e8e46a95
--- /dev/null
+++ b/clang/test/Modules/Inputs/anon-namespace/b1.h
@@ -0,0 +1,2 @@
+namespace N {}
+namespace N { namespace {} }
diff --git a/clang/test/Modules/Inputs/anon-namespace/b2.h b/clang/test/Modules/Inputs/anon-namespace/b2.h
new file mode 100644
index 00000000000..8e7535f3626
--- /dev/null
+++ b/clang/test/Modules/Inputs/anon-namespace/b2.h
@@ -0,0 +1,2 @@
+#include "a.h"
+namespace N {}
diff --git a/clang/test/Modules/Inputs/anon-namespace/c.h b/clang/test/Modules/Inputs/anon-namespace/c.h
new file mode 100644
index 00000000000..fe71f4004e4
--- /dev/null
+++ b/clang/test/Modules/Inputs/anon-namespace/c.h
@@ -0,0 +1 @@
+namespace N {}
diff --git a/clang/test/Modules/Inputs/anon-namespace/module.modulemap b/clang/test/Modules/Inputs/anon-namespace/module.modulemap
new file mode 100644
index 00000000000..3d390d2d4e7
--- /dev/null
+++ b/clang/test/Modules/Inputs/anon-namespace/module.modulemap
@@ -0,0 +1,3 @@
+module a { header "a.h" export * }
+module b { module b1 { header "b1.h" export * } module b2 { header "b2.h" export * } }
+module c { header "c.h" export * }
diff --git a/clang/test/Modules/anon-namespace.cpp b/clang/test/Modules/anon-namespace.cpp
new file mode 100644
index 00000000000..6c085ebc885
--- /dev/null
+++ b/clang/test/Modules/anon-namespace.cpp
@@ -0,0 +1,6 @@
+// RUN: rm -rf %t
+// RUN: %clang_cc1 -fmodules -fmodules-cache-path=%t -I%S/Inputs/anon-namespace -verify %s
+// expected-no-diagnostics
+#include "b1.h"
+#include "c.h"
+using namespace N;