AsmPrinter: Check subprogram before using it

Check return of `getDISubprogram()` before using it.  A WIP patch makes
`DIDescriptor` accessors more strict (and would crash on this).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@232838 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/CodeGen/AsmPrinter/WinCodeViewLineTables.cpp b/lib/CodeGen/AsmPrinter/WinCodeViewLineTables.cpp
index 96a503679027b93d82caa8f398c2df4501feea94..d2b4eec76f92e211ddb92618809fbf87cf3815c4 100644 (file)
--- a/lib/CodeGen/AsmPrinter/WinCodeViewLineTables.cpp
+++ b/lib/CodeGen/AsmPrinter/WinCodeViewLineTables.cpp
@@ -190,8 +190,11 @@ void WinCodeViewLineTables::emitDebugInfoForFunction(const Function *GV) {
     return;
   assert(FI.End && "Don't know where the function ends?");
 
-  StringRef FuncName = getDISubprogram(GV).getDisplayName(),
-            GVName = GV->getName();
+  StringRef GVName = GV->getName();
+  StringRef FuncName;
+  if (DISubprogram SP = getDISubprogram(GV))
+    FuncName = SP.getDisplayName();
+
   // FIXME Clang currently sets DisplayName to "bar" for a C++
   // "namespace_foo::bar" function, see PR21528.  Luckily, dbghelp.dll is trying
   // to demangle display names anyways, so let's just put a mangled name into