Adding support for warning when a non-C compatible user-defined type is returned from an extern "C" function.

Fixes bug 6143

llvm-svn: 150128

1 files changed, 38 insertions, 0 deletions

diff --git a/clang/test/SemaCXX/function-extern-c.cpp b/clang/test/SemaCXX/function-extern-c.cpp
new file mode 100644
index 00000000000..f20cd38a3cb
--- /dev/null
+++ b/clang/test/SemaCXX/function-extern-c.cpp
@@ -0,0 +1,38 @@
+// RUN: %clang_cc1 -Wreturn-type -fsyntax-only -std=c++11 -verify %s
+
+class A {
+public:
+  A(const A&);
+};
+
+struct S {
+  int i;
+  double d;
+
+  virtual void B() {}
+};
+
+union U {
+  struct {
+    int i;
+    virtual void B() {} // Can only do this in C++11
+  } t;
+};
+
+struct S2 {
+  int i;
+  double d;
+};
+
+extern "C" U f3( void ); // expected-warning {{'f3' has C-linkage specified, but returns user-defined type 'U' which is incompatible with C}}
+extern "C" S f0(void); // expected-warning {{'f0' has C-linkage specified, but returns user-defined type 'S' which is incompatible with C}}
+extern "C" A f4( void ); // expected-warning {{'f4' has C-linkage specified, but returns user-defined type 'A' which is incompatible with C}}
+
+// These should all be fine
+extern "C" S2 f5( void );
+extern "C" void f2( A x );
+extern "C" void f6( S s );
+extern "C" void f7( U u );
+extern "C" double f8(void);
+extern "C" long long f11( void );
+extern "C" A *f10( void );