Andrii reported that __unused is a field in /usr/include/bits/stat.h and
vmlinux.h (generated by bpftool), so use the Linux kernel jargon for
this and rename it to '__maybe_unused'.
Reported-by: Andrii Nakryiko <andrii.nakryiko@gmail.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
So that we handle const pointers, also zalloc() is much simpler just
calling calloc(1, size).
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Add support to detect kernel module ftrace addresses and use
it as filter for detected functions.
For kernel modules the ftrace addresses are stored in __mcount_loc
section. Adding the code that detects this section and reads
its data into array, which is then processed as filter by
current code.
There's one tricky point with kernel modules wrt Elf object,
which we get from dwfl_module_getelf function. This function
performs all possible relocations, including __mcount_loc
section.
So addrs array contains relocated values, which we need take
into account when we compare them to functions values which
are relative to their sections.
With this change for example for xfs.ko module in my kernel
config, I'm getting slightly bigger number of functions:
before: 2373, after: 2601
The ftrace's available_filter_functions still shows 2701, but
it includes functions like:
suffix_kstrtoint.constprop.0
xchk_btree_check_minrecs.isra.0
xfs_ascii_ci_compname.part.0
which are not part of dwarf data, the rest matches BTF functions.
Because of the malfunction DWARF's declaration tag, the 'before'
functions contain also functions that are not part of the module.
The 'after' functions contain only functions that are traceable
and part of xfs.ko.
Despite filtering out some declarations, this change also adds
static functions, hence the total number of functions is bigger.
Committer notes:
Andrii test notes:
<quote>
I've tested locally on bpf_testmod that I'm adding to selftests in [0].
All worked well. I changed the test function from global to non-inlined
static, and BTF had it. And the tests passed. So LGTM.
[0] https://patchwork.kernel.org/user/todo/netdevbpf/?series=395715&delegate=121173&state=*
</>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Tested-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Hao Luo <haoluo@google.com>
Cc: Yonghong Song <yhs@fb.com>
Cc: bpf@vger.kernel.org
Cc: dwarves@vger.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
I.e. when we do:
pahole -C a,b,c,d binary
We want that the 'a' type be processed first, etc. So add a list for
that.
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Addressing this build warning:
In file included from /home/acme/git/pahole/dutil.c:10:
/home/acme/git/pahole/dutil.h: In function ‘strstarts’:
/home/acme/git/pahole/dutil.h:301:9: warning: implicit declaration of function ‘strncmp’ [-Wimplicit-function-declaration]
return strncmp(str, prefix, strlen(prefix)) == 0;
^~~~~~~
/home/acme/git/pahole/dutil.h:301:30: warning: implicit declaration of function ‘strlen’ [-Wimplicit-function-declaration]
return strncmp(str, prefix, strlen(prefix)) == 0;
^~~~~~
/home/acme/git/pahole/dutil.h:301:30: warning: incompatible implicit declaration of built-in function ‘strlen’
/home/acme/git/pahole/dutil.h:301:30: note: include ‘<string.h>’ or provide a declaration of ‘strlen’
/home/acme/git/pahole/dutil.h:20:1:
+#include <string.h>
/home/acme/git/pahole/dutil.h:301:30:
return strncmp(str, prefix, strlen(prefix)) == 0;
^~~~~~
Fixes: a2cdc6c2a0 ("dutil: Adopt strstart() from the linux perf tools sources")
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
To clear this warning:
[ 97%] Building C object CMakeFiles/pdwtags.dir/pdwtags.o
In file included from /home/acme/git/pahole/dwarves.h:19,
from /home/acme/git/pahole/pdwtags.c:14:
/home/acme/git/pahole/dutil.h:155:1: warning: ignoring attribute ‘noreturn’ because it conflicts with attribute ‘const’ [-Wattributes]
int ____ilog2_NaN(void);
^~~
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
To deal with unrepresentable constant logarithms we end up causing a
build error, provide the declaration so that the compiler shut up.
Taken, as the other related code, from the Linux kernel sources.
For reference, the warning:
[ 40%] Building C object CMakeFiles/dwarves_reorganize.dir/dwarves_reorganize.o
/home/acme/git/pahole/dwarves_reorganize.c: In function ‘class__demote_bitfields’:
/home/acme/git/pahole/dwarves_reorganize.c:536:168: warning: implicit declaration of function ‘____ilog2_NaN’ [-Wimplicit-function-declaration]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
As Thomas Gleixner wisely pointed out, using 'self' is stoopid, it
doesn't convey useful information, so use sensible names
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
The changeset:
commit f043528
Author: Arnaldo Carvalho de Melo <acme@redhat.com>
Date: Sun Aug 16 12:26:33 2009 -0300
dwarves_reorganize: Fix class__demote_bitfields, we need power of
two bytes
Had a correct changeset description, but an incorrect implementation, it
was not rouding up to the next power of two, but to the next multiple of
2, i.e. when a bitfield has 2 bits, it was deciding it needed 2 bytes,
not 1.
Fix it by copying the roundup_power_of_two code from the Linux kernel,
mostly by David Howells <dhowells@redhat.com>.
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
RHEL5 and Fedora 11 were not building due to the GNU attributes stuff,
cope with that using a define we know is not present in both RHEL5 and
Fedora 11 to #ifdef those parts. Ugly, but _ELFUTILS_PREREQ, i.e.
elfutils/version.h is not present in RHEL5 either.
Reported-by: Jon Stanley <jstanley@fedoraproject.org>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
With this a "make allyesconfig" on a 2.6.29-rc8 Linux kernel build left 16
cases flagged by ctfdwdiff, 8 unique ones, out of 6209 single-cu (compile unit)
.o files.
But what this clearly shows is that we really need to detect if a struct is
packed, and wether it is naturally packed or if __attribute__ packed was used,
that way we will have more clues as to if a enum is packed or if the whole
struct where it is used as a type for a/several member(s) is packed.
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Amazing how many crept up over time, should have set the
execute bit of .git/hooks/pre-commit already, duh.
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Had to be a big sweeping change, but the regression tests shows just
improvements :-)
Now we stop using an id in struct tag, only storing the type, that now
uses 16 bits only, as CTF does.
Each format loader has to go on adding the types to the core, that
figures out if it is a tag that can be on the tag->type field
(tag__is_tag_type).
Formats that already have the types separated and in sequence, such as
CTF, just ask the core to insert in the types_table directly with its
original ID.
For DWARF, we ask the core to put it on the table, in sequence, and return the
index, that is then stashed with the DWARF specific info (original id, type,
decl_line, etc) and hashed by the original id. Later we recode everything,
looking up via the original type, getting the small_id to put on the tag->type.
The underlying debugging info not needed by the core is stashed in tag->priv,
and the DWARF loader now just allocates sizeof(struct dwarf_tag) at the end of
the core tag and points it there, and makes that info available thru
cu->orig_info. In the future we can ask, when loading a cu, that this info be
trown away, so that we reduce the memory footprint for big multi-cu files such
as the Linux kernel.
There is also a routine to ask for inserting a NULL, as we still have
bugs in the CTF decoding and thus some entries are being lost, to avoid
using an undefined pointer when traversing the types_table the ctf
loader puts a NULL there via cu__table_nullify_type_entry() and then
cu__for_each_type skips those.
There is some more cleanups for leftovers that I avoided cleaning to
reduce this changeset.
And also while doing this I saw that enums can appear without any
enumerators and that an array with DW_TAG_GNU_vector is actually a
different tag, encoded this way till we get to DWARF4 ;-)
So now we don't have to lookup on a hash table looking for DWARF
offsets, we can do the more sensible thing of just indexing the
types_tags array.
Now to do some cleanups and try to get the per cu encoder done. Then
order all the cus per number of type entries, pick the one with more,
then go on merging/recoding the types of the others and putting the
parent linkage in place.
Just to show the extent of the changes:
$ codiff /tmp/libdwarves.so.1.0.0 build/libdwarves.so.1.0.0
/home/acme/git/pahole/dwarves.c:
struct cu | -4048
struct tag | -32
struct ptr_to_member_type | -32
struct namespace | -32
struct type | -32
struct class | -32
struct base_type | -32
struct array_type | -32
struct class_member | -32
struct lexblock | -32
struct ftype | -32
struct function | -64
struct parameter | -32
struct variable | -32
struct inline_expansion | -32
struct label | -32
struct enumerator | -32
17 structs changed
tag__follow_typedef | +3
tag__fprintf_decl_info | +25
array_type__fprintf | +6
type__name | -126
type__find_first_biggest_size_base_type_member | -3
typedef__fprintf | +16
imported_declaration__fprintf | +6
imported_module__fprintf | +3
cu__new | +26
cu__delete | +26
hashtags__hash | -65
hash_64 | -124
hlist_add_head | -78
hashtags__find | -157
cu__hash | -80
cu__add_tag | +20
tag__prefix | -3
cu__find_tag_by_id | -2
cu__find_type_by_id | -3
cu__find_first_typedef_of_type | +38
cu__find_base_type_by_name | +68
cu__find_base_type_by_name_and_size | +72
cu__find_struct_by_name | +59
cus__find_struct_by_name | +8
cus__find_tag_by_id | +5
cus__find_cu_by_name | -6
lexblock__find_tag_by_id | -173
cu__find_variable_by_id | -197
list__find_tag_by_id | -308
cu__find_parameter_by_id | -60
tag__ptr_name | +6
tag__name | +15
variable__type | +13
variable__name | +7
class_member__size | +6
parameter__name | -119
tag__parameter | -14
parameter__type | -143
type__fprintf | -29
union__fprintf | +6
class__add_vtable_entry | -9
type__add_member | -6
type__clone_members | -3
enumeration__add | -6
function__name | -156
ftype__has_parm_of_type | -39
class__find_holes | -27
class__has_hole_ge | -3
type__nr_members_of_type | +3
lexblock__account_inline_expansions | +3
cu__account_inline_expansions | -18
ftype__fprintf_parms | +46
function__tag_fprintf | +24
lexblock__fprintf | -6
ftype__fprintf | +3
function__fprintf_stats | -18
function__size | -6
class__vtable_fprintf | -11
class__fprintf | -21
tag__fprintf | -35
60 functions changed, 513 bytes added, 2054 bytes removed, diff: -1541
/home/acme/git/pahole/ctf_loader.c:
struct ctf_short_type | +0
14 structs changed
type__init | -14
type__new | -9
class__new | -12
create_new_base_type | -7
create_new_base_type_float | -7
create_new_array | -8
create_new_subroutine_type | -9
create_full_members | -18
create_short_members | -18
create_new_class | +1
create_new_union | +1
create_new_enumeration | -19
create_new_forward_decl | -2
create_new_typedef | +3
create_new_tag | -5
load_types | +16
class__fixup_ctf_bitfields | -3
17 functions changed, 21 bytes added, 131 bytes removed, diff: -110
/home/acme/git/pahole/dwarf_loader.c:
17 structs changed
zalloc | -56
tag__init | +3
array_type__new | +20
type__init | -24
class_member__new | +46
inline_expansion__new | +12
class__new | +81
lexblock__init | +19
function__new | +43
die__create_new_array | +20
die__create_new_parameter | +4
die__create_new_label | +4
die__create_new_subroutine_type | +113
die__create_new_enumeration | -21
die__process_class | +79
die__process_namespace | +76
die__create_new_inline_expansion | +4
die__process_function | +147
__die__process_tag | +34
die__process_unit | +56
die__process | +90
21 functions changed, 851 bytes added, 101 bytes removed, diff: +750
/home/acme/git/pahole/dwarves.c:
struct ptr_table | +16
struct cu_orig_info | +32
2 structs changed
tag__decl_line | +68
tag__decl_file | +70
tag__orig_id | +71
ptr_table__init | +46
ptr_table__exit | +37
ptr_table__add | +183
ptr_table__add_with_id | +165
ptr_table__entry | +64
cu__table_add_tag | +171
cu__table_nullify_type_entry | +38
10 functions changed, 913 bytes added, diff: +913
/home/acme/git/pahole/ctf_loader.c:
2 structs changed
tag__alloc | +52
1 function changed, 52 bytes added, diff: +52
/home/acme/git/pahole/dwarf_loader.c:
struct dwarf_tag | +48
struct dwarf_cu | +4104
4 structs changed
dwarf_cu__init | +83
hashtags__hash | +61
hash_64 | +124
hlist_add_head | +78
hashtags__find | +161
cu__hash | +95
tag__is_tag_type | +171
tag__is_type | +85
tag__is_union | +28
tag__is_struct | +57
tag__is_typedef | +28
tag__is_enumeration | +28
dwarf_cu__find_tag_by_id | +56
dwarf_cu__find_type_by_id | +63
tag__alloc | +114
__tag__print_type_not_found | +108
namespace__recode_dwarf_types | +346
tag__namespace | +14
tag__has_namespace | +86
tag__is_namespace | +28
type__recode_dwarf_specification | +182
tag__type | +14
__tag__print_abstract_origin_not_found | +105
ftype__recode_dwarf_types | +322
tag__ftype | +14
tag__parameter | +14
lexblock__recode_dwarf_types | +736
tag__lexblock | +14
tag__label | +14
tag__recode_dwarf_type | +766
tag__ptr_to_member_type | +14
cu__recode_dwarf_types_table | +88
cu__recode_dwarf_types | +48
dwarf_tag__decl_file | +77
strings__ptr | +33
dwarf_tag__decl_line | +59
dwarf_tag__orig_id | +59
dwarf_tag__orig_type | +59
38 functions changed, 4432 bytes added, diff: +4432
build/libdwarves.so.1.0.0:
147 functions changed, 6782 bytes added, 2286 bytes removed, diff: +4496
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Now at creation time we specify if the strings must be allocated or if using
the pointer directly.
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Arnaldo Carvalho de Melo
Jiri Olsa
Domenico Andreoli