PR6400: Handle an extreme edge case in mangling correctly.

llvm-svn: 96961

2 files changed, 9 insertions, 0 deletions

diff --git a/clang/lib/CodeGen/Mangle.cpp b/clang/lib/CodeGen/Mangle.cpp
index a302225c7f7..123ce613387 100644
--- a/clang/lib/CodeGen/Mangle.cpp
+++ b/clang/lib/CodeGen/Mangle.cpp
@@ -1652,6 +1652,9 @@ bool CXXNameMangler::mangleStandardSubstitution(const NamedDecl *ND) {
     //                            ::std::char_traits<char>,
     //                            ::std::allocator<char> >
     if (SD->getIdentifier()->isStr("basic_string")) {
+      if (!isStdNamespace(SD->getDeclContext()))
+        return false;
+
       const TemplateArgumentList &TemplateArgs = SD->getTemplateArgs();
 
       if (TemplateArgs.size() != 3)
diff --git a/clang/test/CodeGenCXX/mangle-subst-std.cpp b/clang/test/CodeGenCXX/mangle-subst-std.cpp
index 913c8f101b5..062610bd74a 100644
--- a/clang/test/CodeGenCXX/mangle-subst-std.cpp
+++ b/clang/test/CodeGenCXX/mangle-subst-std.cpp
@@ -55,3 +55,9 @@ namespace std
   terminate_handler set_terminate(terminate_handler) { return 0; }
 }
 }
+
+// Make sure we don't treat the following like std::string
+// CHECK: define void @_Z1f12basic_stringIcSt11char_traitsIcESaIcEE
+template<typename, typename, typename> struct basic_string { };
+typedef basic_string<char, std::char_traits<char>, std::allocator<char> > not_string;
+void f(not_string) { }