Debug info: fix emitting struct names

When emitting debug info for structs (which will be translated into
BTF), the name *must not* contain the "struct" (or "union") prefix,
otherwise our emitted debug info will not match the kernel BTF (which
doesn't use the prefix) and the programs where the match is required
will be rejected.

Author: viktormalik

src/ast/dibuilderbpf.cpp

@@ -212,8 +212,14 @@ DIType *DIBuilderBPF::CreateByteArrayType(uint64_t num_bytes)
 DIType *DIBuilderBPF::GetType(const SizedType &stype, bool emit_codegen_types)
 {
   if (!emit_codegen_types && stype.IsRecordTy()) {
+    std::string name = stype.GetName();
+    if (name.find("struct ") == 0)
+      name = name.substr(std::string("struct ").length());
+    else if (name.find("union ") == 0)
+      name = name.substr(std::string("union ").length());
+
     return createStructType(file,
-                            stype.GetName(),
+                            name,
                             file,
                             0,
                             stype.GetSize() * 8,

tests/codegen/llvm/call_len_map_sum_elem_count.ll

@@ -117,5 +117,5 @@ attributes #1 = { nocallback nofree nosync nounwind willreturn memory(argmem: re
 !61 = !DISubroutineType(types: !62)
 !62 = !{!18, !63}
 !63 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !64, size: 64)
-!64 = !DICompositeType(tag: DW_TAG_structure_type, name: "struct bpf_map", scope: !2, file: !2, elements: !65)
+!64 = !DICompositeType(tag: DW_TAG_structure_type, name: "bpf_map", scope: !2, file: !2, elements: !65)
 !65 = !{}