Bugfix for nullptr check by klocwork

Klocwork static check:
Pointer from call to function `DebugLoc::operator DILocation *() const `
may be NULL and will be dereference in function `printExtendedName```
Patch by Shengchen Kan (skan)
Differential Revision: https://reviews.llvm.org/D61715

llvm-svn: 360317
diff --git a/llvm/lib/CodeGen/LiveDebugVariables.cpp b/llvm/lib/CodeGen/LiveDebugVariables.cpp
index 65d3071..648d3ee 100644
--- a/llvm/lib/CodeGen/LiveDebugVariables.cpp
+++ b/llvm/lib/CodeGen/LiveDebugVariables.cpp
@@ -504,7 +504,8 @@
 
   if (!Res.empty())
     OS << Res << "," << Line;
-  if (auto *InlinedAt = DL->getInlinedAt()) {
+  auto *InlinedAt = DL ? DL->getInlinedAt() : nullptr;
+  if (InlinedAt) {
     if (DebugLoc InlinedAtDL = InlinedAt) {
       OS << " @[";
       printDebugLoc(InlinedAtDL, OS, Ctx);