[Sanitize] fix crash in -fsanitize-annotate-debug-info (#149237)

Author: fmayer

clang/lib/CodeGen/CGDebugInfo.cpp

@@ -6480,24 +6480,27 @@ SanitizerOrdinalToCheckLabel(SanitizerKind::SanitizerOrdinal Ordinal) {
 llvm::DILocation *CodeGenFunction::SanitizerAnnotateDebugInfo(
     ArrayRef<SanitizerKind::SanitizerOrdinal> Ordinals,
     SanitizerHandler Handler) {
+  llvm::DILocation *CheckDebugLoc = Builder.getCurrentDebugLocation();
+  auto *DI = getDebugInfo();
+  if (!DI)
+    return CheckDebugLoc;
+
   std::string Label;
   if (Ordinals.size() == 1)
     Label = SanitizerOrdinalToCheckLabel(Ordinals[0]);
   else
     Label = SanitizerHandlerToCheckLabel(Handler);
 
-  llvm::DILocation *CheckDI = Builder.getCurrentDebugLocation();
-
   for (auto Ord : Ordinals) {
     // TODO: deprecate ClArrayBoundsPseudoFn
     if (((ClArrayBoundsPseudoFn && Ord == SanitizerKind::SO_ArrayBounds) ||
          CGM.getCodeGenOpts().SanitizeAnnotateDebugInfo.has(Ord)) &&
-        CheckDI) {
-      return getDebugInfo()->CreateSyntheticInlineAt(CheckDI, Label);
+        CheckDebugLoc) {
+      return DI->CreateSyntheticInlineAt(CheckDebugLoc, Label);
     }
   }
 
-  return CheckDI;
+  return CheckDebugLoc;
 }
 
 SanitizerDebugLocation::SanitizerDebugLocation(

clang/test/CodeGen/null-sanitizer-debug-info-regression.cpp

@@ -0,0 +1,5 @@
+// RUN: %clangxx -g -fsanitize=null -fsanitize-trap=all -fsanitize-annotate-debug-info=all -O2 -std=c++17 -c -o /dev/null %s
+
+struct foo {
+  foo(int, long, const int & = int());
+} foo(0, 0);