Don't crash when mangling empty anonymous unions. We never actually *need*

these, but it's convenient to mangle them when deferring them (in the 99.99%
case where it's not an anonymous union, of course).



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@110381 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 16 insertions, 1 deletions

diff --git a/lib/CodeGen/Mangle.cpp b/lib/CodeGen/Mangle.cpp
index b5f629aeb5..7bdbabc8c0 100644
--- a/lib/CodeGen/Mangle.cpp
+++ b/lib/CodeGen/Mangle.cpp
@@ -699,7 +699,11 @@ void CXXNameMangler::mangleUnqualifiedName(const NamedDecl *ND,
       //   a program to refer to the anonymous union, and there is therefore no
       //   need to mangle its name.
       const FieldDecl *FD = FindFirstNamedDataMember(RD);
-      assert(FD && "Didn't find a named data member!");
+
+      // It's actually possible for various reasons for us to get here
+      // with an empty anonymous struct / union.  Fortunately, it
+      // doesn't really matter what name we generate.
+      if (!FD) break;
       assert(FD->getIdentifier() && "Data member name isn't an identifier!");
       
       mangleSourceName(FD->getIdentifier());
diff --git a/test/CodeGenCXX/mangle.cpp b/test/CodeGenCXX/mangle.cpp
index 3a2e112f16..4152dabc0b 100644
--- a/test/CodeGenCXX/mangle.cpp
+++ b/test/CodeGenCXX/mangle.cpp
@@ -529,3 +529,14 @@ namespace test15 {
   // CHECK: define weak_odr void @_ZN6test151fILi7EEEvNS_1SIXplT_LNS_1EE3EEEE(
   template void f<7>(S<7 + e>);
 }
+
+// rdar://problem/8125400.  Don't crash.
+namespace test16 {
+  static union {};
+  static union { union {}; };
+  static union { struct {}; };
+  static union { union { union {}; }; };
+  static union { union { struct {}; }; };
+  static union { struct { union {}; }; };
+  static union { struct { struct {}; }; };
+}