fix a null pointer deref issue

[skan]

Summary

[static check]
Pointer from call to function `DebugLoc::operator DILocation *() const ` may be NULL and will be dereference in function `printExtendedName```.

[jdoerfert]

LGTM

llvm/trunk/lib/CodeGen/LiveDebugVariables.cpp

if (const auto *V = dyn_cast<const DILocalVariable>(Node)) {
     Line = V->getLine();
   } else if (const auto *L = dyn_cast<const DILabel>(Node)) {
     Res = L->getName();
     Line = L->getLine();
   }
 
   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);
       OS << "]";
     }
   }
 }