Unwrap CountAttributed for debug info (#86017)

Fix crash caused by 3eb9ff3

Author: rapidsna

clang/lib/CodeGen/CGDebugInfo.cpp

@@ -3463,6 +3463,9 @@ static QualType UnwrapTypeForDebugInfo(QualType T, const ASTContext &C) {
     case Type::BTFTagAttributed:
       T = cast<BTFTagAttributedType>(T)->getWrappedType();
       break;
+    case Type::CountAttributed:
+      T = cast<CountAttributedType>(T)->desugar();
+      break;
     case Type::Elaborated:
       T = cast<ElaboratedType>(T)->getNamedType();
       break;

clang/test/CodeGen/attr-counted-by-debug-info.c

@@ -0,0 +1,18 @@
+// RUN: %clang -emit-llvm -DCOUNTED_BY -S -g %s -o - | FileCheck %s
+// RUN: %clang -emit-llvm -S -g %s -o - | FileCheck %s
+
+#ifdef COUNTED_BY
+#define __counted_by(member)    __attribute__((__counted_by__(member)))
+#else
+#define __counted_by(member)
+#endif
+
+struct {
+  int num_counters;
+  long value[] __counted_by(num_counters);
+} agent_send_response_port_num;
+
+// CHECK: !DICompositeType(tag: DW_TAG_array_type, baseType: ![[BT:.*]], elements: ![[ELEMENTS:.*]])
+// CHECK: ![[BT]] = !DIBasicType(name: "long", size: {{.*}}, encoding: DW_ATE_signed)
+// CHECK: ![[ELEMENTS]] = !{![[COUNT:.*]]}
+// CHECK: ![[COUNT]] = !DISubrange(count: -1)