patch-r271282-clang-r200797-r200798-r200805-debug-info-crash.diff revision 271414 
1diff --git a/lib/CodeGen/CGDebugInfo.cpp b/lib/CodeGen/CGDebugInfo.cpp
2index 59ba47c..dddc7e7 100644
3--- a/lib/CodeGen/CGDebugInfo.cpp
4+++ b/lib/CodeGen/CGDebugInfo.cpp
5@@ -2251,9 +2251,10 @@ llvm::DICompositeType CGDebugInfo::CreateLimitedType(const RecordType *Ty) {
6   if (T && (!T.isForwardDecl() || !RD->getDefinition()))
7       return T;
8 
9-  // If this is just a forward declaration, construct an appropriately
10-  // marked node and just return it.
11-  if (!RD->getDefinition())
12+  // If this is just a forward or incomplete declaration, construct an
13+  // appropriately marked node and just return it.
14+  const RecordDecl *D = RD->getDefinition();
15+  if (!D || !D->isCompleteDefinition())
16     return getOrCreateRecordFwdDecl(Ty, RDContext);
17 
18   uint64_t Size = CGM.getContext().getTypeSize(Ty);
19diff --git a/test/CodeGenCXX/debug-info-template-fwd.cpp b/test/CodeGenCXX/debug-info-template-fwd.cpp
20new file mode 100644
21index 0000000..b2b7073
22--- /dev/null
23+++ b/test/CodeGenCXX/debug-info-template-fwd.cpp
24@@ -0,0 +1,27 @@
25+// RUN: %clang_cc1 %s -triple=x86_64-apple-darwin -g -emit-llvm -o - | FileCheck %s
26+// This test is for a crash when emitting debug info for not-yet-completed
27+// types.
28+// Test that we don't actually emit a forward decl for the offending class:
29+// CHECK:  [ DW_TAG_structure_type ] [Derived<int>] {{.*}} [def]
30+// rdar://problem/15931354
31+template <class A> class Derived;
32+
33+template <class A> class Base {
34+  static Derived<A> *create();
35+};
36+
37+template <class A> struct Derived : Base<A> {
38+};
39+
40+Base<int> *f;
41+
42+// During the instantiation of Derived<int>, Base<int> becomes required to be
43+// complete - since the declaration has already been emitted (due to 'f',
44+// above), we immediately try to build debug info for Base<int> which then
45+// requires the (incomplete definition) of Derived<int> which is problematic.
46+//
47+// (if 'f' is not present, the point at which Base<int> becomes required to be
48+// complete during the instantiation of Derived<int> is a no-op because
49+// Base<int> was never emitted so we ignore it and carry on until we
50+// wire up the base class of Derived<int> in the debug info later on)
51+Derived<int> d;
52