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selftests/btf: add initial BTF dedup tests
authorAndrii Nakryiko <andriin@fb.com>
Tue, 5 Feb 2019 01:29:46 +0000 (17:29 -0800)
committerDaniel Borkmann <daniel@iogearbox.net>
Tue, 5 Feb 2019 15:52:57 +0000 (16:52 +0100)
This patch sets up a new kind of tests (BTF dedup tests) and tests few aspects of
BTF dedup algorithm. More complete set of tests will come in follow up patches.

Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
tools/lib/bpf/btf.c
tools/lib/bpf/btf.h
tools/lib/bpf/libbpf.map
tools/testing/selftests/bpf/test_btf.c

index e5097be..4949f88 100644 (file)
@@ -237,6 +237,11 @@ static int btf_parse_type_sec(struct btf *btf)
        return 0;
 }
 
+__u32 btf__get_nr_types(const struct btf *btf)
+{
+       return btf->nr_types;
+}
+
 const struct btf_type *btf__type_by_id(const struct btf *btf, __u32 type_id)
 {
        if (type_id > btf->nr_types)
@@ -427,6 +432,13 @@ int btf__fd(const struct btf *btf)
        return btf->fd;
 }
 
+void btf__get_strings(const struct btf *btf, const char **strings,
+                     __u32 *str_len)
+{
+       *strings = btf->strings;
+       *str_len = btf->hdr->str_len;
+}
+
 const char *btf__name_by_offset(const struct btf *btf, __u32 offset)
 {
        if (offset < btf->hdr->str_len)
index c739de7..25a9d2d 100644 (file)
@@ -59,11 +59,14 @@ LIBBPF_API void btf__free(struct btf *btf);
 LIBBPF_API struct btf *btf__new(__u8 *data, __u32 size);
 LIBBPF_API __s32 btf__find_by_name(const struct btf *btf,
                                   const char *type_name);
+LIBBPF_API __u32 btf__get_nr_types(const struct btf *btf);
 LIBBPF_API const struct btf_type *btf__type_by_id(const struct btf *btf,
                                                  __u32 id);
 LIBBPF_API __s64 btf__resolve_size(const struct btf *btf, __u32 type_id);
 LIBBPF_API int btf__resolve_type(const struct btf *btf, __u32 type_id);
 LIBBPF_API int btf__fd(const struct btf *btf);
+LIBBPF_API void btf__get_strings(const struct btf *btf, const char **strings,
+                                __u32 *str_len);
 LIBBPF_API const char *btf__name_by_offset(const struct btf *btf, __u32 offset);
 LIBBPF_API int btf__get_from_id(__u32 id, struct btf **btf);
 LIBBPF_API int btf__get_map_kv_tids(const struct btf *btf, char *map_name,
index 7e4a8c1..89c1149 100644 (file)
@@ -135,6 +135,8 @@ LIBBPF_0.0.2 {
                bpf_get_link_xdp_id;
                btf__dedup;
                btf__get_map_kv_tids;
+               btf__get_nr_types;
+               btf__get_strings;
                btf_ext__free;
                btf_ext__func_info_rec_size;
                btf_ext__line_info_rec_size;
index 5afab82..30c3edd 100644 (file)
@@ -70,12 +70,21 @@ static int __base_pr(enum libbpf_print_level level __attribute__((unused)),
        BTF_TYPE_ENC(name, BTF_INFO_ENC(BTF_KIND_INT, 0, 0), sz),       \
        BTF_INT_ENC(encoding, bits_offset, bits)
 
+#define BTF_FWD_ENC(name, kind_flag) \
+       BTF_TYPE_ENC(name, BTF_INFO_ENC(BTF_KIND_FWD, kind_flag, 0), 0)
+
 #define BTF_ARRAY_ENC(type, index_type, nr_elems)      \
        (type), (index_type), (nr_elems)
 #define BTF_TYPE_ARRAY_ENC(type, index_type, nr_elems) \
        BTF_TYPE_ENC(0, BTF_INFO_ENC(BTF_KIND_ARRAY, 0, 0), 0), \
        BTF_ARRAY_ENC(type, index_type, nr_elems)
 
+#define BTF_STRUCT_ENC(name, nr_elems, sz)     \
+       BTF_TYPE_ENC(name, BTF_INFO_ENC(BTF_KIND_STRUCT, 0, nr_elems), sz)
+
+#define BTF_UNION_ENC(name, nr_elems, sz)      \
+       BTF_TYPE_ENC(name, BTF_INFO_ENC(BTF_KIND_UNION, 0, nr_elems), sz)
+
 #define BTF_MEMBER_ENC(name, type, bits_offset)        \
        (name), (type), (bits_offset)
 #define BTF_ENUM_ENC(name, val) (name), (val)
@@ -91,6 +100,12 @@ static int __base_pr(enum libbpf_print_level level __attribute__((unused)),
 #define BTF_CONST_ENC(type) \
        BTF_TYPE_ENC(0, BTF_INFO_ENC(BTF_KIND_CONST, 0, 0), type)
 
+#define BTF_VOLATILE_ENC(type) \
+       BTF_TYPE_ENC(0, BTF_INFO_ENC(BTF_KIND_VOLATILE, 0, 0), type)
+
+#define BTF_RESTRICT_ENC(type) \
+       BTF_TYPE_ENC(0, BTF_INFO_ENC(BTF_KIND_RESTRICT, 0, 0), type)
+
 #define BTF_FUNC_PROTO_ENC(ret_type, nargs) \
        BTF_TYPE_ENC(0, BTF_INFO_ENC(BTF_KIND_FUNC_PROTO, 0, nargs), ret_type)
 
@@ -103,6 +118,10 @@ static int __base_pr(enum libbpf_print_level level __attribute__((unused)),
 #define BTF_END_RAW 0xdeadbeef
 #define NAME_TBD 0xdeadb33f
 
+#define NAME_NTH(N) (0xffff0000 | N)
+#define IS_NAME_NTH(X) ((X & 0xffff0000) == 0xffff0000)
+#define GET_NAME_NTH_IDX(X) (X & 0x0000ffff)
+
 #define MAX_NR_RAW_U32 1024
 #define BTF_LOG_BUF_SIZE 65535
 
@@ -111,12 +130,14 @@ static struct args {
        unsigned int file_test_num;
        unsigned int get_info_test_num;
        unsigned int info_raw_test_num;
+       unsigned int dedup_test_num;
        bool raw_test;
        bool file_test;
        bool get_info_test;
        bool pprint_test;
        bool always_log;
        bool info_raw_test;
+       bool dedup_test;
 } args;
 
 static char btf_log_buf[BTF_LOG_BUF_SIZE];
@@ -2827,11 +2848,13 @@ static void *btf_raw_create(const struct btf_header *hdr,
                            const char **ret_next_str)
 {
        const char *next_str = str, *end_str = str + str_sec_size;
+       const char **strs_idx = NULL, **tmp_strs_idx;
+       int strs_cap = 0, strs_cnt = 0, next_str_idx = 0;
        unsigned int size_needed, offset;
        struct btf_header *ret_hdr;
-       int i, type_sec_size;
+       int i, type_sec_size, err = 0;
        uint32_t *ret_types;
-       void *raw_btf;
+       void *raw_btf = NULL;
 
        type_sec_size = get_raw_sec_size(raw_types);
        if (CHECK(type_sec_size < 0, "Cannot get nr_raw_types"))
@@ -2846,17 +2869,44 @@ static void *btf_raw_create(const struct btf_header *hdr,
        memcpy(raw_btf, hdr, sizeof(*hdr));
        offset = sizeof(*hdr);
 
+       /* Index strings */
+       while ((next_str = get_next_str(next_str, end_str))) {
+               if (strs_cnt == strs_cap) {
+                       strs_cap += max(16, strs_cap / 2);
+                       tmp_strs_idx = realloc(strs_idx,
+                                              sizeof(*strs_idx) * strs_cap);
+                       if (CHECK(!tmp_strs_idx,
+                                 "Cannot allocate memory for strs_idx")) {
+                               err = -1;
+                               goto done;
+                       }
+                       strs_idx = tmp_strs_idx;
+               }
+               strs_idx[strs_cnt++] = next_str;
+               next_str += strlen(next_str);
+       }
+
        /* Copy type section */
        ret_types = raw_btf + offset;
        for (i = 0; i < type_sec_size / sizeof(raw_types[0]); i++) {
                if (raw_types[i] == NAME_TBD) {
-                       next_str = get_next_str(next_str, end_str);
-                       if (CHECK(!next_str, "Error in getting next_str")) {
-                               free(raw_btf);
-                               return NULL;
+                       if (CHECK(next_str_idx == strs_cnt,
+                                 "Error in getting next_str #%d",
+                                 next_str_idx)) {
+                               err = -1;
+                               goto done;
                        }
-                       ret_types[i] = next_str - str;
-                       next_str += strlen(next_str);
+                       ret_types[i] = strs_idx[next_str_idx++] - str;
+               } else if (IS_NAME_NTH(raw_types[i])) {
+                       int idx = GET_NAME_NTH_IDX(raw_types[i]);
+
+                       if (CHECK(idx <= 0 || idx > strs_cnt,
+                                 "Error getting string #%d, strs_cnt:%d",
+                                 idx, strs_cnt)) {
+                               err = -1;
+                               goto done;
+                       }
+                       ret_types[i] = strs_idx[idx-1] - str;
                } else {
                        ret_types[i] = raw_types[i];
                }
@@ -2873,8 +2923,17 @@ static void *btf_raw_create(const struct btf_header *hdr,
 
        *btf_size = size_needed;
        if (ret_next_str)
-               *ret_next_str = next_str;
+               *ret_next_str =
+                       next_str_idx < strs_cnt ? strs_idx[next_str_idx] : NULL;
 
+done:
+       if (err) {
+               if (raw_btf)
+                       free(raw_btf);
+               if (strs_idx)
+                       free(strs_idx);
+               return NULL;
+       }
        return raw_btf;
 }
 
@@ -5543,20 +5602,450 @@ static int test_info_raw(void)
        return err;
 }
 
+struct btf_raw_data {
+       __u32 raw_types[MAX_NR_RAW_U32];
+       const char *str_sec;
+       __u32 str_sec_size;
+};
+
+struct btf_dedup_test {
+       const char *descr;
+       struct btf_raw_data input;
+       struct btf_raw_data expect;
+       struct btf_dedup_opts opts;
+};
+
+const struct btf_dedup_test dedup_tests[] = {
+
+{
+       .descr = "dedup: unused strings filtering",
+       .input = {
+               .raw_types = {
+                       BTF_TYPE_INT_ENC(NAME_NTH(2), BTF_INT_SIGNED, 0, 32, 4),
+                       BTF_TYPE_INT_ENC(NAME_NTH(5), BTF_INT_SIGNED, 0, 64, 8),
+                       BTF_END_RAW,
+               },
+               BTF_STR_SEC("\0unused\0int\0foo\0bar\0long"),
+       },
+       .expect = {
+               .raw_types = {
+                       BTF_TYPE_INT_ENC(NAME_NTH(1), BTF_INT_SIGNED, 0, 32, 4),
+                       BTF_TYPE_INT_ENC(NAME_NTH(2), BTF_INT_SIGNED, 0, 64, 8),
+                       BTF_END_RAW,
+               },
+               BTF_STR_SEC("\0int\0long"),
+       },
+       .opts = {
+               .dont_resolve_fwds = false,
+       },
+},
+{
+       .descr = "dedup: strings deduplication",
+       .input = {
+               .raw_types = {
+                       BTF_TYPE_INT_ENC(NAME_NTH(1), BTF_INT_SIGNED, 0, 32, 4),
+                       BTF_TYPE_INT_ENC(NAME_NTH(2), BTF_INT_SIGNED, 0, 64, 8),
+                       BTF_TYPE_INT_ENC(NAME_NTH(3), BTF_INT_SIGNED, 0, 32, 4),
+                       BTF_TYPE_INT_ENC(NAME_NTH(4), BTF_INT_SIGNED, 0, 64, 8),
+                       BTF_TYPE_INT_ENC(NAME_NTH(5), BTF_INT_SIGNED, 0, 32, 4),
+                       BTF_END_RAW,
+               },
+               BTF_STR_SEC("\0int\0long int\0int\0long int\0int"),
+       },
+       .expect = {
+               .raw_types = {
+                       BTF_TYPE_INT_ENC(NAME_NTH(1), BTF_INT_SIGNED, 0, 32, 4),
+                       BTF_TYPE_INT_ENC(NAME_NTH(2), BTF_INT_SIGNED, 0, 64, 8),
+                       BTF_END_RAW,
+               },
+               BTF_STR_SEC("\0int\0long int"),
+       },
+       .opts = {
+               .dont_resolve_fwds = false,
+       },
+},
+{
+       .descr = "dedup: struct example #1",
+       /*
+        * struct s {
+        *      struct s *next;
+        *      const int *a;
+        *      int b[16];
+        *      int c;
+        * }
+        */
+       .input = {
+               .raw_types = {
+                       /* int */
+                       BTF_TYPE_INT_ENC(NAME_NTH(1), BTF_INT_SIGNED, 0, 32, 4),        /* [1] */
+                       /* int[16] */
+                       BTF_TYPE_ARRAY_ENC(1, 1, 16),                                   /* [2] */
+                       /* struct s { */
+                       BTF_STRUCT_ENC(NAME_NTH(2), 4, 84),                             /* [3] */
+                               BTF_MEMBER_ENC(NAME_NTH(3), 4, 0),      /* struct s *next;      */
+                               BTF_MEMBER_ENC(NAME_NTH(4), 5, 64),     /* const int *a;        */
+                               BTF_MEMBER_ENC(NAME_NTH(5), 2, 128),    /* int b[16];           */
+                               BTF_MEMBER_ENC(NAME_NTH(6), 1, 640),    /* int c;               */
+                       /* ptr -> [3] struct s */
+                       BTF_PTR_ENC(3),                                                 /* [4] */
+                       /* ptr -> [6] const int */
+                       BTF_PTR_ENC(6),                                                 /* [5] */
+                       /* const -> [1] int */
+                       BTF_CONST_ENC(1),                                               /* [6] */
+
+                       /* full copy of the above */
+                       BTF_TYPE_INT_ENC(NAME_NTH(1), BTF_INT_SIGNED, 0, 32, 4),        /* [7] */
+                       BTF_TYPE_ARRAY_ENC(7, 7, 16),                                   /* [8] */
+                       BTF_STRUCT_ENC(NAME_NTH(2), 4, 84),                             /* [9] */
+                               BTF_MEMBER_ENC(NAME_NTH(3), 10, 0),
+                               BTF_MEMBER_ENC(NAME_NTH(4), 11, 64),
+                               BTF_MEMBER_ENC(NAME_NTH(5), 8, 128),
+                               BTF_MEMBER_ENC(NAME_NTH(6), 7, 640),
+                       BTF_PTR_ENC(9),                                                 /* [10] */
+                       BTF_PTR_ENC(12),                                                /* [11] */
+                       BTF_CONST_ENC(7),                                               /* [12] */
+                       BTF_END_RAW,
+               },
+               BTF_STR_SEC("\0int\0s\0next\0a\0b\0c\0"),
+       },
+       .expect = {
+               .raw_types = {
+                       /* int */
+                       BTF_TYPE_INT_ENC(NAME_NTH(4), BTF_INT_SIGNED, 0, 32, 4),        /* [1] */
+                       /* int[16] */
+                       BTF_TYPE_ARRAY_ENC(1, 1, 16),                                   /* [2] */
+                       /* struct s { */
+                       BTF_STRUCT_ENC(NAME_NTH(6), 4, 84),                             /* [3] */
+                               BTF_MEMBER_ENC(NAME_NTH(5), 4, 0),      /* struct s *next;      */
+                               BTF_MEMBER_ENC(NAME_NTH(1), 5, 64),     /* const int *a;        */
+                               BTF_MEMBER_ENC(NAME_NTH(2), 2, 128),    /* int b[16];           */
+                               BTF_MEMBER_ENC(NAME_NTH(3), 1, 640),    /* int c;               */
+                       /* ptr -> [3] struct s */
+                       BTF_PTR_ENC(3),                                                 /* [4] */
+                       /* ptr -> [6] const int */
+                       BTF_PTR_ENC(6),                                                 /* [5] */
+                       /* const -> [1] int */
+                       BTF_CONST_ENC(1),                                               /* [6] */
+                       BTF_END_RAW,
+               },
+               BTF_STR_SEC("\0a\0b\0c\0int\0next\0s"),
+       },
+       .opts = {
+               .dont_resolve_fwds = false,
+       },
+},
+{
+       .descr = "dedup: all possible kinds (no duplicates)",
+       .input = {
+               .raw_types = {
+                       BTF_TYPE_INT_ENC(NAME_TBD, BTF_INT_SIGNED, 0, 32, 8),           /* [1] int */
+                       BTF_TYPE_ENC(NAME_TBD, BTF_INFO_ENC(BTF_KIND_ENUM, 0, 2), 4),   /* [2] enum */
+                               BTF_ENUM_ENC(NAME_TBD, 0),
+                               BTF_ENUM_ENC(NAME_TBD, 1),
+                       BTF_FWD_ENC(NAME_TBD, 1 /* union kind_flag */),                 /* [3] fwd */
+                       BTF_TYPE_ARRAY_ENC(2, 1, 7),                                    /* [4] array */
+                       BTF_STRUCT_ENC(NAME_TBD, 1, 4),                                 /* [5] struct */
+                               BTF_MEMBER_ENC(NAME_TBD, 1, 0),
+                       BTF_UNION_ENC(NAME_TBD, 1, 4),                                  /* [6] union */
+                               BTF_MEMBER_ENC(NAME_TBD, 1, 0),
+                       BTF_TYPEDEF_ENC(NAME_TBD, 1),                                   /* [7] typedef */
+                       BTF_PTR_ENC(0),                                                 /* [8] ptr */
+                       BTF_CONST_ENC(8),                                               /* [9] const */
+                       BTF_VOLATILE_ENC(8),                                            /* [10] volatile */
+                       BTF_RESTRICT_ENC(8),                                            /* [11] restrict */
+                       BTF_FUNC_PROTO_ENC(1, 2),                                       /* [12] func_proto */
+                               BTF_FUNC_PROTO_ARG_ENC(NAME_TBD, 1),
+                               BTF_FUNC_PROTO_ARG_ENC(NAME_TBD, 8),
+                       BTF_FUNC_ENC(NAME_TBD, 12),                                     /* [13] func */
+                       BTF_END_RAW,
+               },
+               BTF_STR_SEC("\0A\0B\0C\0D\0E\0F\0G\0H\0I\0J\0K\0L\0M"),
+       },
+       .expect = {
+               .raw_types = {
+                       BTF_TYPE_INT_ENC(NAME_TBD, BTF_INT_SIGNED, 0, 32, 8),           /* [1] int */
+                       BTF_TYPE_ENC(NAME_TBD, BTF_INFO_ENC(BTF_KIND_ENUM, 0, 2), 4),   /* [2] enum */
+                               BTF_ENUM_ENC(NAME_TBD, 0),
+                               BTF_ENUM_ENC(NAME_TBD, 1),
+                       BTF_FWD_ENC(NAME_TBD, 1 /* union kind_flag */),                 /* [3] fwd */
+                       BTF_TYPE_ARRAY_ENC(2, 1, 7),                                    /* [4] array */
+                       BTF_STRUCT_ENC(NAME_TBD, 1, 4),                                 /* [5] struct */
+                               BTF_MEMBER_ENC(NAME_TBD, 1, 0),
+                       BTF_UNION_ENC(NAME_TBD, 1, 4),                                  /* [6] union */
+                               BTF_MEMBER_ENC(NAME_TBD, 1, 0),
+                       BTF_TYPEDEF_ENC(NAME_TBD, 1),                                   /* [7] typedef */
+                       BTF_PTR_ENC(0),                                                 /* [8] ptr */
+                       BTF_CONST_ENC(8),                                               /* [9] const */
+                       BTF_VOLATILE_ENC(8),                                            /* [10] volatile */
+                       BTF_RESTRICT_ENC(8),                                            /* [11] restrict */
+                       BTF_FUNC_PROTO_ENC(1, 2),                                       /* [12] func_proto */
+                               BTF_FUNC_PROTO_ARG_ENC(NAME_TBD, 1),
+                               BTF_FUNC_PROTO_ARG_ENC(NAME_TBD, 8),
+                       BTF_FUNC_ENC(NAME_TBD, 12),                                     /* [13] func */
+                       BTF_END_RAW,
+               },
+               BTF_STR_SEC("\0A\0B\0C\0D\0E\0F\0G\0H\0I\0J\0K\0L\0M"),
+       },
+       .opts = {
+               .dont_resolve_fwds = false,
+       },
+},
+{
+       .descr = "dedup: no int duplicates",
+       .input = {
+               .raw_types = {
+                       BTF_TYPE_INT_ENC(NAME_NTH(1), BTF_INT_SIGNED, 0, 32, 8),
+                       /* different name */
+                       BTF_TYPE_INT_ENC(NAME_NTH(2), BTF_INT_SIGNED, 0, 32, 8),
+                       /* different encoding */
+                       BTF_TYPE_INT_ENC(NAME_NTH(1), BTF_INT_CHAR, 0, 32, 8),
+                       BTF_TYPE_INT_ENC(NAME_NTH(1), BTF_INT_BOOL, 0, 32, 8),
+                       /* different bit offset */
+                       BTF_TYPE_INT_ENC(NAME_NTH(1), BTF_INT_SIGNED, 8, 32, 8),
+                       /* different bit size */
+                       BTF_TYPE_INT_ENC(NAME_NTH(1), BTF_INT_SIGNED, 0, 27, 8),
+                       /* different byte size */
+                       BTF_TYPE_INT_ENC(NAME_NTH(1), BTF_INT_SIGNED, 0, 32, 4),
+                       BTF_END_RAW,
+               },
+               BTF_STR_SEC("\0int\0some other int"),
+       },
+       .expect = {
+               .raw_types = {
+                       BTF_TYPE_INT_ENC(NAME_NTH(1), BTF_INT_SIGNED, 0, 32, 8),
+                       /* different name */
+                       BTF_TYPE_INT_ENC(NAME_NTH(2), BTF_INT_SIGNED, 0, 32, 8),
+                       /* different encoding */
+                       BTF_TYPE_INT_ENC(NAME_NTH(1), BTF_INT_CHAR, 0, 32, 8),
+                       BTF_TYPE_INT_ENC(NAME_NTH(1), BTF_INT_BOOL, 0, 32, 8),
+                       /* different bit offset */
+                       BTF_TYPE_INT_ENC(NAME_NTH(1), BTF_INT_SIGNED, 8, 32, 8),
+                       /* different bit size */
+                       BTF_TYPE_INT_ENC(NAME_NTH(1), BTF_INT_SIGNED, 0, 27, 8),
+                       /* different byte size */
+                       BTF_TYPE_INT_ENC(NAME_NTH(1), BTF_INT_SIGNED, 0, 32, 4),
+                       BTF_END_RAW,
+               },
+               BTF_STR_SEC("\0int\0some other int"),
+       },
+       .opts = {
+               .dont_resolve_fwds = false,
+       },
+},
+
+};
+
+static int btf_type_size(const struct btf_type *t)
+{
+       int base_size = sizeof(struct btf_type);
+       __u16 vlen = BTF_INFO_VLEN(t->info);
+       __u16 kind = BTF_INFO_KIND(t->info);
+
+       switch (kind) {
+       case BTF_KIND_FWD:
+       case BTF_KIND_CONST:
+       case BTF_KIND_VOLATILE:
+       case BTF_KIND_RESTRICT:
+       case BTF_KIND_PTR:
+       case BTF_KIND_TYPEDEF:
+       case BTF_KIND_FUNC:
+               return base_size;
+       case BTF_KIND_INT:
+               return base_size + sizeof(__u32);
+       case BTF_KIND_ENUM:
+               return base_size + vlen * sizeof(struct btf_enum);
+       case BTF_KIND_ARRAY:
+               return base_size + sizeof(struct btf_array);
+       case BTF_KIND_STRUCT:
+       case BTF_KIND_UNION:
+               return base_size + vlen * sizeof(struct btf_member);
+       case BTF_KIND_FUNC_PROTO:
+               return base_size + vlen * sizeof(struct btf_param);
+       default:
+               fprintf(stderr, "Unsupported BTF_KIND:%u\n", kind);
+               return -EINVAL;
+       }
+}
+
+static void dump_btf_strings(const char *strs, __u32 len)
+{
+       const char *cur = strs;
+       int i = 0;
+
+       while (cur < strs + len) {
+               fprintf(stderr, "string #%d: '%s'\n", i, cur);
+               cur += strlen(cur) + 1;
+               i++;
+       }
+}
+
+static int do_test_dedup(unsigned int test_num)
+{
+       const struct btf_dedup_test *test = &dedup_tests[test_num - 1];
+       int err = 0, i;
+       __u32 test_nr_types, expect_nr_types, test_str_len, expect_str_len;
+       void *raw_btf;
+       unsigned int raw_btf_size;
+       struct btf *test_btf = NULL, *expect_btf = NULL;
+       const char *ret_test_next_str, *ret_expect_next_str;
+       const char *test_strs, *expect_strs;
+       const char *test_str_cur, *test_str_end;
+       const char *expect_str_cur, *expect_str_end;
+
+       fprintf(stderr, "BTF dedup test[%u] (%s):", test_num, test->descr);
+
+       raw_btf = btf_raw_create(&hdr_tmpl, test->input.raw_types,
+                                test->input.str_sec, test->input.str_sec_size,
+                                &raw_btf_size, &ret_test_next_str);
+       if (!raw_btf)
+               return -1;
+       test_btf = btf__new((__u8 *)raw_btf, raw_btf_size);
+       free(raw_btf);
+       if (CHECK(IS_ERR(test_btf), "invalid test_btf errno:%ld",
+                 PTR_ERR(test_btf))) {
+               err = -1;
+               goto done;
+       }
+
+       raw_btf = btf_raw_create(&hdr_tmpl, test->expect.raw_types,
+                                test->expect.str_sec,
+                                test->expect.str_sec_size,
+                                &raw_btf_size, &ret_expect_next_str);
+       if (!raw_btf)
+               return -1;
+       expect_btf = btf__new((__u8 *)raw_btf, raw_btf_size);
+       free(raw_btf);
+       if (CHECK(IS_ERR(expect_btf), "invalid expect_btf errno:%ld",
+                 PTR_ERR(expect_btf))) {
+               err = -1;
+               goto done;
+       }
+
+       err = btf__dedup(test_btf, NULL, &test->opts);
+       if (CHECK(err, "btf_dedup failed errno:%d", err)) {
+               err = -1;
+               goto done;
+       }
+
+       btf__get_strings(test_btf, &test_strs, &test_str_len);
+       btf__get_strings(expect_btf, &expect_strs, &expect_str_len);
+       if (CHECK(test_str_len != expect_str_len,
+                 "test_str_len:%u != expect_str_len:%u",
+                 test_str_len, expect_str_len)) {
+               fprintf(stderr, "\ntest strings:\n");
+               dump_btf_strings(test_strs, test_str_len);
+               fprintf(stderr, "\nexpected strings:\n");
+               dump_btf_strings(expect_strs, expect_str_len);
+               err = -1;
+               goto done;
+       }
+
+       test_str_cur = test_strs;
+       test_str_end = test_strs + test_str_len;
+       expect_str_cur = expect_strs;
+       expect_str_end = expect_strs + expect_str_len;
+       while (test_str_cur < test_str_end && expect_str_cur < expect_str_end) {
+               size_t test_len, expect_len;
+
+               test_len = strlen(test_str_cur);
+               expect_len = strlen(expect_str_cur);
+               if (CHECK(test_len != expect_len,
+                         "test_len:%zu != expect_len:%zu "
+                         "(test_str:%s, expect_str:%s)",
+                         test_len, expect_len, test_str_cur, expect_str_cur)) {
+                       err = -1;
+                       goto done;
+               }
+               if (CHECK(strcmp(test_str_cur, expect_str_cur),
+                         "test_str:%s != expect_str:%s",
+                         test_str_cur, expect_str_cur)) {
+                       err = -1;
+                       goto done;
+               }
+               test_str_cur += test_len + 1;
+               expect_str_cur += expect_len + 1;
+       }
+       if (CHECK(test_str_cur != test_str_end,
+                 "test_str_cur:%p != test_str_end:%p",
+                 test_str_cur, test_str_end)) {
+               err = -1;
+               goto done;
+       }
+
+       test_nr_types = btf__get_nr_types(test_btf);
+       expect_nr_types = btf__get_nr_types(expect_btf);
+       if (CHECK(test_nr_types != expect_nr_types,
+                 "test_nr_types:%u != expect_nr_types:%u",
+                 test_nr_types, expect_nr_types)) {
+               err = -1;
+               goto done;
+       }
+
+       for (i = 1; i <= test_nr_types; i++) {
+               const struct btf_type *test_type, *expect_type;
+               int test_size, expect_size;
+
+               test_type = btf__type_by_id(test_btf, i);
+               expect_type = btf__type_by_id(expect_btf, i);
+               test_size = btf_type_size(test_type);
+               expect_size = btf_type_size(expect_type);
+
+               if (CHECK(test_size != expect_size,
+                         "type #%d: test_size:%d != expect_size:%u",
+                         i, test_size, expect_size)) {
+                       err = -1;
+                       goto done;
+               }
+               if (CHECK(memcmp((void *)test_type,
+                                (void *)expect_type,
+                                test_size),
+                         "type #%d: contents differ", i)) {
+                       err = -1;
+                       goto done;
+               }
+       }
+
+done:
+       if (!err)
+               fprintf(stderr, "OK");
+       if (!IS_ERR(test_btf))
+               btf__free(test_btf);
+       if (!IS_ERR(expect_btf))
+               btf__free(expect_btf);
+
+       return err;
+}
+
+static int test_dedup(void)
+{
+       unsigned int i;
+       int err = 0;
+
+       if (args.dedup_test_num)
+               return count_result(do_test_dedup(args.dedup_test_num));
+
+       for (i = 1; i <= ARRAY_SIZE(dedup_tests); i++)
+               err |= count_result(do_test_dedup(i));
+
+       return err;
+}
+
 static void usage(const char *cmd)
 {
        fprintf(stderr, "Usage: %s [-l] [[-r btf_raw_test_num (1 - %zu)] |\n"
                        "\t[-g btf_get_info_test_num (1 - %zu)] |\n"
                        "\t[-f btf_file_test_num (1 - %zu)] |\n"
                        "\t[-k btf_prog_info_raw_test_num (1 - %zu)] |\n"
-                       "\t[-p (pretty print test)]]\n",
+                       "\t[-p (pretty print test)] |\n"
+                       "\t[-d btf_dedup_test_num (1 - %zu)]]\n",
                cmd, ARRAY_SIZE(raw_tests), ARRAY_SIZE(get_info_tests),
-               ARRAY_SIZE(file_tests), ARRAY_SIZE(info_raw_tests));
+               ARRAY_SIZE(file_tests), ARRAY_SIZE(info_raw_tests),
+               ARRAY_SIZE(dedup_tests));
 }
 
 static int parse_args(int argc, char **argv)
 {
-       const char *optstr = "lpk:f:r:g:";
+       const char *optstr = "hlpk:f:r:g:d:";
        int opt;
 
        while ((opt = getopt(argc, argv, optstr)) != -1) {
@@ -5583,12 +6072,16 @@ static int parse_args(int argc, char **argv)
                        args.info_raw_test_num = atoi(optarg);
                        args.info_raw_test = true;
                        break;
+               case 'd':
+                       args.dedup_test_num = atoi(optarg);
+                       args.dedup_test = true;
+                       break;
                case 'h':
                        usage(argv[0]);
                        exit(0);
                default:
-                               usage(argv[0]);
-                               return -1;
+                       usage(argv[0]);
+                       return -1;
                }
        }
 
@@ -5624,6 +6117,14 @@ static int parse_args(int argc, char **argv)
                return -1;
        }
 
+       if (args.dedup_test_num &&
+           (args.dedup_test_num < 1 ||
+            args.dedup_test_num > ARRAY_SIZE(dedup_tests))) {
+               fprintf(stderr, "BTF dedup test number must be [1 - %zu]\n",
+                       ARRAY_SIZE(dedup_tests));
+               return -1;
+       }
+
        return 0;
 }
 
@@ -5659,14 +6160,18 @@ int main(int argc, char **argv)
        if (args.info_raw_test)
                err |= test_info_raw();
 
+       if (args.dedup_test)
+               err |= test_dedup();
+
        if (args.raw_test || args.get_info_test || args.file_test ||
-           args.pprint_test || args.info_raw_test)
+           args.pprint_test || args.info_raw_test || args.dedup_test)
                goto done;
 
        err |= test_raw();
        err |= test_get_info();
        err |= test_file();
        err |= test_info_raw();
+       err |= test_dedup();
 
 done:
        print_summary();