Basic ODR checking for C++ modules:

If we have multiple definitions of the same entity from different modules, we
nominate the first definition which we see as being the canonical definition.
If we load a declaration from a different definition and we can't find a
corresponding declaration in the canonical definition, issue a diagnostic.

This is insufficient to prevent things from going horribly wrong in all cases
-- we might be in the middle of emitting IR for a function when we trigger some
deserialization and discover that it refers to an incoherent piece of the AST,
by which point it's probably too late to bail out -- but we'll at least produce
a diagnostic.

llvm-svn: 192950

1 files changed, 20 insertions, 0 deletions

diff --git a/clang/test/Modules/odr.cpp b/clang/test/Modules/odr.cpp
new file mode 100644
index 00000000000..5ab10d2ce41
--- /dev/null
+++ b/clang/test/Modules/odr.cpp
@@ -0,0 +1,20 @@
+// RUN: rm -rf %t
+// RUN: %clang_cc1 -x objective-c++ -fmodules -fmodules-cache-path=%t -I %S/Inputs/odr %s -verify -std=c++11
+
+// expected-error@a.h:8 {{'X::n' from module 'a' is not present in definition of 'X' provided earlier}}
+struct X { // expected-note {{definition has no member 'n'}}
+};
+
+@import a;
+@import b;
+
+// Trigger the declarations from a and b to be imported.
+int x = f() + g();
+
+// expected-note@a.h:5 {{definition has no member 'e2'}}
+// expected-note@a.h:3 {{declaration of 'f' does not match}}
+// expected-note@a.h:1 {{definition has no member 'm'}}
+
+// expected-error@b.h:5 {{'E::e2' from module 'b' is not present in definition of 'E' in module 'a'}}
+// expected-error@b.h:3 {{'Y::f' from module 'b' is not present in definition of 'Y' in module 'a'}}
+// expected-error@b.h:2 {{'Y::m' from module 'b' is not present in definition of 'Y' in module 'a'}}