Add a test to ensure that obvious link messages are actually produced on

the standard error.

llvm-svn: 41116

llvm/test/Linker/link-messages.ll

@@ -0,0 +1,11 @@
+; Test that linking two files with the same definition causes an error and
+; that error is printed out.
+; RUN: llvm-as %s -o %t.one.bc -f
+; RUN: llvm-as %s -o %t.two.bc -f
+; RUN: ignore llvm-ld -disable-opt -link-as-library %t.one.bc %t.two.bc \
+; RUN:   -o %t.bc 2>%t.err 
+; RUN: grep "Function is already defined" %t.err
+
+define i32 @bar() {
+	ret i32 0
+}