BTF_KIND_ENUM64 is supported with latest libbpf, which
supports 64-bit enum values. Latest libbpf also supports
signedness for enum values. Add enum64 support in
dwarf-to-btf conversion.
The following is an example of new encoding which covers
signed/unsigned enum64/enum variations.
$cat t.c
enum { /* signed, enum64 */
A = -1,
B = 0xffffffff,
} g1;
enum { /* unsigned, enum64 */
C = 1,
D = 0xfffffffff,
} g2;
enum { /* signed, enum */
E = -1,
F = 0xfffffff,
} g3;
enum { /* unsigned, enum */
G = 1,
H = 0xfffffff,
} g4;
$ clang -g -c t.c
$ pahole -JV t.o
btf_encoder__new: 't.o' doesn't have '.data..percpu' section
Found 0 per-CPU variables!
File t.o:
[1] ENUM64 (anon) size=8
A val=-1
B val=4294967295
[2] INT long size=8 nr_bits=64 encoding=SIGNED
[3] ENUM64 (anon) size=8
C val=1
D val=68719476735
[4] INT unsigned long size=8 nr_bits=64 encoding=(none)
[5] ENUM (anon) size=4
E val=-1
F val=268435455
[6] INT int size=4 nr_bits=32 encoding=SIGNED
[7] ENUM (anon) size=4
G val=1
H val=268435455
[8] INT unsigned int size=4 nr_bits=32 encoding=(none)
With the flag to skip enum64 encoding,
$ pahole -JV t.o --skip_encoding_btf_enum64
btf_encoder__new: 't.o' doesn't have '.data..percpu' section
Found 0 per-CPU variables!
File t.o:
[1] ENUM (anon) size=8
A val=4294967295
B val=4294967295
[2] INT long size=8 nr_bits=64 encoding=SIGNED
[3] ENUM (anon) size=8
C val=1
D val=4294967295
[4] INT unsigned long size=8 nr_bits=64 encoding=(none)
[5] ENUM (anon) size=4
E val=4294967295
F val=268435455
[6] INT int size=4 nr_bits=32 encoding=SIGNED
[7] ENUM (anon) size=4
G val=1
H val=268435455
[8] INT unsigned int size=4 nr_bits=32 encoding=(none)
In the above btf encoding without enum64, all enum types
with the same type size as the corresponding enum64. All these
enum types have unsigned type (kflag = 0) which is required
before kernel enum64 support.
Acked-by: Andrii Nakryiko <andrii@xxxxxxxxxx>
Signed-off-by: Yonghong Song <yhs@xxxxxx>
---
btf_encoder.c | 67 +++++++++++++++++++++++++++++++++++------------
btf_encoder.h | 2 +-
dwarf_loader.c | 12 +++++++++
dwarves.h | 4 ++-
dwarves_fprintf.c | 6 ++++-
pahole.c | 10 ++++++-
6 files changed, 80 insertions(+), 21 deletions(-)
diff --git a/btf_encoder.c b/btf_encoder.c
index 9e708e4..daa8e3b 100644
--- a/btf_encoder.c
+++ b/btf_encoder.c
@@ -144,6 +144,7 @@ static const char * const btf_kind_str[NR_BTF_KINDS] = {
[BTF_KIND_FLOAT] = "FLOAT",
[BTF_KIND_DECL_TAG] = "DECL_TAG",
[BTF_KIND_TYPE_TAG] = "TYPE_TAG",
+ [BTF_KIND_ENUM64] = "ENUM64",
};
static const char *btf__printable_name(const struct btf *btf, uint32_t offset)
@@ -490,34 +491,64 @@ static int32_t btf_encoder__add_struct(struct btf_encoder *encoder, uint8_t kind
return id;
}
-static int32_t btf_encoder__add_enum(struct btf_encoder *encoder, const char *name, uint32_t bit_size)
+static int32_t btf_encoder__add_enum(struct btf_encoder *encoder, const char *name, struct type *etype,
+ struct conf_load *conf_load)
{
struct btf *btf = encoder->btf;
const struct btf_type *t;
int32_t id, size;
+ bool is_enum32;
- size = BITS_ROUNDUP_BYTES(bit_size);
- id = btf__add_enum(btf, name, size);
+ size = BITS_ROUNDUP_BYTES(etype->size);
+ is_enum32 = size <= 4 || conf_load->skip_encoding_btf_enum64;
+ if (is_enum32)
+ id = btf__add_enum(btf, name, size);
+ else
+ id = btf__add_enum64(btf, name, size, etype->is_signed_enum);
if (id > 0) {
t = btf__type_by_id(btf, id);
btf_encoder__log_type(encoder, t, false, true, "size=%u", t->size);
} else {
- btf__log_err(btf, BTF_KIND_ENUM, name, true,
+ btf__log_err(btf, is_enum32 ? BTF_KIND_ENUM : BTF_KIND_ENUM64, name, true,
"size=%u Error emitting BTF type", size);
}
return id;
}
-static int btf_encoder__add_enum_val(struct btf_encoder *encoder, const char *name, int32_t value)
+static int btf_encoder__add_enum_val(struct btf_encoder *encoder, const char *name, int64_t value,
+ struct type *etype, struct conf_load *conf_load)
{
- int err = btf__add_enum_value(encoder->btf, name, value);
+ const char *fmt_str;
+ int err;
+
+ /* If enum64 is not allowed, generate enum32 with unsigned int value. In enum64-supported
+ * libbpf library, btf__add_enum_value() will set the kflag (sign bit) in common_type
+ * if the value is negative.
+ */
+ if (conf_load->skip_encoding_btf_enum64)
+ err = btf__add_enum_value(encoder->btf, name, (uint32_t)value);
+ else if (etype->size > 32)
+ err = btf__add_enum64_value(encoder->btf, name, value);
+ else
+ err = btf__add_enum_value(encoder->btf, name, value);
if (!err) {
- if (encoder->verbose)
- printf("\t%s val=%d\n", name, value);
+ if (encoder->verbose) {
+ if (conf_load->skip_encoding_btf_enum64) {
+ printf("\t%s val=%u\n", name, (uint32_t)value);
+ } else {
+ fmt_str = etype->is_signed_enum ? "\t%s val=%lld\n" : "\t%s val=%llu\n";
+ printf(fmt_str, name, (unsigned long long)value);
+ }
+ }
} else {
- fprintf(stderr, "\t%s val=%d Error emitting BTF enum value\n",
- name, value);
+ if (conf_load->skip_encoding_btf_enum64) {
+ fprintf(stderr, "\t%s val=%u Error emitting BTF enum value\n", name, (uint32_t)value);
+ } else {
+ fmt_str = etype->is_signed_enum ? "\t%s val=%lld Error emitting BTF enum value\n"
+ : "\t%s val=%llu Error emitting BTF enum value\n";
+ fprintf(stderr, fmt_str, name, (unsigned long long)value);
+ }
}
return err;
}
@@ -844,27 +875,29 @@ static uint32_t array_type__nelems(struct tag *tag)
return nelem;
}
-static int32_t btf_encoder__add_enum_type(struct btf_encoder *encoder, struct tag *tag)
+static int32_t btf_encoder__add_enum_type(struct btf_encoder *encoder, struct tag *tag,
+ struct conf_load *conf_load)
{
struct type *etype = tag__type(tag);
struct enumerator *pos;
const char *name = type__name(etype);
int32_t type_id;
- type_id = btf_encoder__add_enum(encoder, name, etype->size);
+ type_id = btf_encoder__add_enum(encoder, name, etype, conf_load);
if (type_id < 0)
return type_id;
type__for_each_enumerator(etype, pos) {
name = enumerator__name(pos);
- if (btf_encoder__add_enum_val(encoder, name, pos->value))
+ if (btf_encoder__add_enum_val(encoder, name, pos->value, etype, conf_load))
return -1;
}
return type_id;
}
-static int btf_encoder__encode_tag(struct btf_encoder *encoder, struct tag *tag, uint32_t type_id_off)
+static int btf_encoder__encode_tag(struct btf_encoder *encoder, struct tag *tag, uint32_t type_id_off,
+ struct conf_load *conf_load)
{
/* single out type 0 as it represents special type "void" */
uint32_t ref_type_id = tag->type == 0 ? 0 : type_id_off + tag->type;
@@ -903,7 +936,7 @@ static int btf_encoder__encode_tag(struct btf_encoder *encoder, struct tag *tag,
encoder->need_index_type = true;
return btf_encoder__add_array(encoder, ref_type_id, encoder->array_index_id, array_type__nelems(tag));
case DW_TAG_enumeration_type:
- return btf_encoder__add_enum_type(encoder, tag);
+ return btf_encoder__add_enum_type(encoder, tag, conf_load);
case DW_TAG_subroutine_type:
return btf_encoder__add_func_proto(encoder, tag__ftype(tag), type_id_off);
default:
@@ -1422,7 +1455,7 @@ void btf_encoder__delete(struct btf_encoder *encoder)
free(encoder);
}
-int btf_encoder__encode_cu(struct btf_encoder *encoder, struct cu *cu)
+int btf_encoder__encode_cu(struct btf_encoder *encoder, struct cu *cu, struct conf_load *conf_load)
{
uint32_t type_id_off = btf__type_cnt(encoder->btf) - 1;
struct llvm_annotation *annot;
@@ -1446,7 +1479,7 @@ int btf_encoder__encode_cu(struct btf_encoder *encoder, struct cu *cu)
}
cu__for_each_type(cu, core_id, pos) {
- btf_type_id = btf_encoder__encode_tag(encoder, pos, type_id_off);
+ btf_type_id = btf_encoder__encode_tag(encoder, pos, type_id_off, conf_load);
if (btf_type_id < 0 ||
tag__check_id_drift(pos, core_id, btf_type_id, type_id_off)) {
diff --git a/btf_encoder.h b/btf_encoder.h
index 339fae2..a65120c 100644
--- a/btf_encoder.h
+++ b/btf_encoder.h
@@ -21,7 +21,7 @@ void btf_encoder__delete(struct btf_encoder *encoder);
int btf_encoder__encode(struct btf_encoder *encoder);
-int btf_encoder__encode_cu(struct btf_encoder *encoder, struct cu *cu);
+int btf_encoder__encode_cu(struct btf_encoder *encoder, struct cu *cu, struct conf_load *conf_load);
void btf_encoders__add(struct list_head *encoders, struct btf_encoder *encoder);
diff --git a/dwarf_loader.c b/dwarf_loader.c
index a0d964b..4767602 100644
--- a/dwarf_loader.c
+++ b/dwarf_loader.c
@@ -632,6 +632,18 @@ static void type__init(struct type *type, Dwarf_Die *die, struct cu *cu, struct
type->resized = 0;
type->nr_members = 0;
type->nr_static_members = 0;
+ type->is_signed_enum = 0;
+
+ Dwarf_Attribute attr;
+ if (dwarf_attr(die, DW_AT_type, &attr) != NULL) {
+ Dwarf_Die type_die;
+ if (dwarf_formref_die(&attr, &type_die) != NULL) {
+ uint64_t encoding = attr_numeric(&type_die, DW_AT_encoding);
+
+ if (encoding == DW_ATE_signed || encoding == DW_ATE_signed_char)
+ type->is_signed_enum = 1;
+ }
+ }
}
static struct type *type__new(Dwarf_Die *die, struct cu *cu, struct conf_load *conf)
diff --git a/dwarves.h b/dwarves.h
index 4d0e4b6..bec9f08 100644
--- a/dwarves.h
+++ b/dwarves.h
@@ -65,6 +65,7 @@ struct conf_load {
bool skip_encoding_btf_decl_tag;
bool skip_missing;
bool skip_encoding_btf_type_tag;
+ bool skip_encoding_btf_enum64;
uint8_t hashtable_bits;
uint8_t max_hashtable_bits;
uint16_t kabi_prefix_len;
@@ -1046,6 +1047,7 @@ struct type {
uint8_t definition_emitted:1;
uint8_t fwd_decl_emitted:1;
uint8_t resized:1;
+ uint8_t is_signed_enum:1;
};
void __type__init(struct type *type);
@@ -1365,7 +1367,7 @@ static inline struct string_type *tag__string_type(const struct tag *tag)
struct enumerator {
struct tag tag;
const char *name;
- uint32_t value;
+ uint64_t value;
struct tag_cu type_enum; // To cache the type_enum searches
};
diff --git a/dwarves_fprintf.c b/dwarves_fprintf.c
index 2cec584..ce64c79 100644
--- a/dwarves_fprintf.c
+++ b/dwarves_fprintf.c
@@ -437,7 +437,11 @@ size_t enumeration__fprintf(const struct tag *tag, const struct conf_fprintf *co
type__for_each_enumerator(type, pos) {
printed += fprintf(fp, "%.*s\t%-*s = ", indent, tabs,
max_entry_name_len, enumerator__name(pos));
- printed += fprintf(fp, conf->hex_fmt ? "%#x" : "%u", pos->value);
+ if (conf->hex_fmt)
+ printed += fprintf(fp, "%#llx", (unsigned long long)pos->value);
+ else
+ printed += fprintf(fp, type->is_signed_enum ? "%lld" : "%llu",
+ (unsigned long long)pos->value);
printed += fprintf(fp, ",\n");
}
diff --git a/pahole.c b/pahole.c
index 78caa08..e87d9a4 100644
--- a/pahole.c
+++ b/pahole.c
@@ -1220,6 +1220,7 @@ ARGP_PROGRAM_VERSION_HOOK_DEF = dwarves_print_version;
#define ARGP_compile 334
#define ARGP_languages 335
#define ARGP_languages_exclude 336
+#define ARGP_skip_encoding_btf_enum64 337
static const struct argp_option pahole__options[] = {
{
@@ -1622,6 +1623,11 @@ static const struct argp_option pahole__options[] = {
.arg = "LANGUAGES",
.doc = "Don't consider compilation units written in these languages"
},
+ {
+ .name = "skip_encoding_btf_enum64",
+ .key = ARGP_skip_encoding_btf_enum64,
+ .doc = "Do not encode ENUM64sin BTF."
+ },
{
.name = NULL,
}
@@ -1787,6 +1793,8 @@ static error_t pahole__options_parser(int key, char *arg,
/* fallthru */
case ARGP_languages:
languages.str = arg; break;
+ case ARGP_skip_encoding_btf_enum64:
+ conf_load.skip_encoding_btf_enum64 = true; break;
default:
return ARGP_ERR_UNKNOWN;
}
@@ -3067,7 +3075,7 @@ static enum load_steal_kind pahole_stealer(struct cu *cu,
encoder = btf_encoder;
}
- if (btf_encoder__encode_cu(encoder, cu)) {
+ if (btf_encoder__encode_cu(encoder, cu, conf_load)) {
fprintf(stderr, "Encountered error while encoding BTF.\n");
exit(1);
}
--
2.30.2
