elf: Add support for map struct typedef

elf_reader.go

@@ -750,7 +750,7 @@ func (ec *elfCode) loadBTFMaps() error {
 			}
 
 			// Each Var representing a BTF map definition contains a Struct.
-			mapStruct, ok := v.Type.(*btf.Struct)
+			mapStruct, ok := btf.UnderlyingType(v.Type).(*btf.Struct)
 			if !ok {
 				return fmt.Errorf("expected struct, got %s", v.Type)
 			}

elf_reader_test.go

@@ -90,6 +90,13 @@ func TestLoadCollectionSpec(t *testing.T) {
 					MaxEntries: 1,
 				},
 			},
+			"btf_typedef_map": {
+				Name:       "btf_typedef_map",
+				Type:       Array,
+				KeySize:    4,
+				ValueSize:  8,
+				MaxEntries: 1,
+			},
 		},
 		Programs: map[string]*ProgramSpec{
 			"xdp_prog": {

testdata/loader.c

@@ -69,6 +69,16 @@ struct bpf_map_def array_of_hash_map __section("maps") = {
 	.max_entries = 2,
 };
 
+typedef struct {
+	__uint(type, BPF_MAP_TYPE_ARRAY);
+	__uint(key_size, sizeof(uint32_t));
+	__uint(value_size, sizeof(uint64_t));
+	__uint(max_entries, 1);
+} array_map_t;
+
+// Map definition behind a typedef.
+array_map_t btf_typedef_map __section(".maps");
+
 static int __attribute__((noinline)) __section("static") static_fn(uint32_t arg) {
 	return arg - 1;
 }