.. _abidiff_label:
=======
abidiff
=======
abidiff compares the Application Binary Interfaces (ABI) of two shared
libraries in `ELF`_ format. It emits a meaningful report describing the
differences between the two ABIs.
This tool can also compare the textual representations of the ABI of
two ELF binaries (as emitted by ``abidw``) or an ELF binary against a
textual representation of another ELF binary.
For a comprehensive ABI change report between two input shared
libraries that includes changes about function and variable sub-types,
``abidiff`` uses by default, debug information in `DWARF`_ format, if
present, otherwise it compares interfaces using debug information in
`CTF`_ or `BTF`_ formats, if present. Finally, if no debug info in
these formats is found, it only considers `ELF`_ symbols and report
about their addition or removal.
.. include:: tools-use-libabigail.txt
.. _abidiff_invocation_label:
Invocation
==========
::
abidiff [options] <first-shared-library> <second-shared-library>
Environment
===========
.. _abidiff_default_supprs_label:
abidiff loads two default :ref:`suppression specifications files
<suppr_spec_label>`, merges their content and use it to filter out ABI
change reports that might be considered as false positives to users.
* Default system-wide suppression specification file
It's located by the optional environment variable
LIBABIGAIL_DEFAULT_SYSTEM_SUPPRESSION_FILE. If that environment
variable is not set, then abidiff tries to load the suppression file
$libdir/libabigail/libabigail-default.abignore. If that file is not
present, then no default system-wide suppression specification file
is loaded.
* Default user suppression specification file.
It's located by the optional environment
LIBABIGAIL_DEFAULT_USER_SUPPRESSION_FILE. If that environment
variable is not set, then abidiff tries to load the suppression file
$HOME/.abignore. If that file is not present, then no default user
suppression specification is loaded.
.. _abidiff_options_label:
Options
=======
* ``--help | -h``
Display a short help about the command and exit.
* ``--debug-self-comparison``
In this mode, error messages are emitted for types which fail type
canonicalization, in some circumstances, when comparing a binary
against itself.
When comparing a binary against itself, canonical types of the
second binary should be equal (as much as possible) to canonical
types of the first binary. When some discrepancies are detected
in this mode, an abort signal is emitted and execution is halted.
This option should be used while executing the tool in a debugger,
for troubleshooting purposes.
This is an optional debugging and sanity check option. To enable
it the libabigail package needs to be configured with
the --enable-debug-self-comparison configure option.
* ``--debug-tc``
In this mode, the process of type canonicalization is put under
heavy scrutiny. Basically, during type canonicalization, each
type comparison is performed twice: once in a structural mode
(comparing every sub-type member-wise), and once using canonical
comparison. The two comparisons should yield the same result.
Otherwise, an abort signal is emitted and the process can be
debugged to understand why the two kinds of comparison yield
different results.
This is an optional debugging and sanity check option. To enable
it the libabigail package needs to be configured with
the --enable-debug-type-canonicalization configure option.
* ``--version | -v``
Display the version of the program and exit.
* ``--debug-info-dir1 | --d1`` <*di-path1*>
For cases where the debug information for *first-shared-library*
is split out into a separate file, tells ``abidiff`` where to find
that separate debug information file.
Note that *di-path* must point to the root directory under which
the debug information is arranged in a tree-like manner. Under
Red Hat based systems, that directory is usually
``<root>/usr/lib/debug``.
This option can be provided several times with different root
directories. In that case, ``abidiff`` will potentially look into
all those root directories to find the split debug info for
*first-shared-library*.
Note also that this option is not mandatory for split debug
information installed by your system's package manager because
then ``abidiff`` knows where to find it.
* ``--debug-info-dir2 | --d2`` <*di-path2*>
Like ``--debug-info-dir1``, this options tells ``abidiff`` where
to find the split debug information for the
*second-shared-library* file.
This option can be provided several times with different root
directories. In that case, ``abidiff`` will potentially look into
all those root directories to find the split debug info for
*second-shared-library*.
* ``--headers-dir1 | --hd1`` <headers-directory-path-1>
Specifies where to find the public headers of the first shared
library (or binary in general) that the tool has to consider. The
tool will thus filter out ABI changes on types that are not
defined in public headers.
Note that several public header directories can be specified for
the first shared library. In that case the ``--headers-dir1``
option should be present several times on the command line, like
in the following example: ::
$ abidiff --headers-dir1 /some/path \
--headers-dir1 /some/other/path \
binary-version-1 binary-version-2
* ``--header-file1 | --hf1`` <header-file-path-1>
Specifies where to find one public header of the first shared
library that the tool has to consider. The tool will thus filter
out ABI changes on types that are not defined in public headers.
* ``--headers-dir2 | --hd2`` <headers-directory-path-2>
Specifies where to find the public headers of the second shared
library that the tool has to consider. The tool will thus filter
out ABI changes on types that are not defined in public headers.
Note that several public header directories can be specified for
the second shared library. In that case the ``--headers-dir2``
option should be present several times like in the following
example: ::
$ abidiff --headers-dir2 /some/path \
--headers-dir2 /some/other/path \
binary-version-1 binary-version-2
* ``--header-file2 | --hf2`` <header-file-path-2>
Specifies where to find one public header of the second shared
library that the tool has to consider. The tool will thus filter
out ABI changes on types that are not defined in public headers.
* ``--add-binaries1`` <*bin1,bin2,bin3,..*>
For each of the comma-separated binaries given in argument to this
option, if the binary is found in the directory specified by the
``--added-binaries-dir1`` option, then ``abidiff`` loads the ABI
corpus of the binary and adds it to a set of corpora (called an
ABI Corpus Group) that includes the first argument of ``abidiff``.
That ABI corpus group is then compared against the second corpus
group given in argument to ``abidiff``.
* ``--add-binaries2`` <*bin1,bin2,bin3,..*>
For each of the comma-separated binaries given in argument to this
option, if the binary is found in the directory specified by the
``--added-binaries-dir2`` option, then ``abidiff`` loads the ABI
corpus of the binary and adds it to a set of corpora(called an ABI
Corpus Group) that includes the second argument of ``abidiff``.
That ABI corpus group is then compared against the first corpus
group given in argument to ``abidiff``.
* ``--follow-dependencies | --fdeps``
For each dependency of the first argument of ``abidiff``, if it's
found in the directory specified by the ``--added-binaries-dir1``
option, then construct an ABI corpus out of the dependency, add it
to a set of corpora (called an ABI Corpus Group) that includes the
first argument of ``abidiff``.
Similarly, for each dependency of the second argument of
``abidiff``, if it's found in the directory specified by the
``--added-binaries-dir2`` option, then construct an ABI corpus out
of the dependency, add it to an ABI corpus group that includes the
second argument of ``abidiff``.
These two ABI corpus groups are then compared against each other.
Said otherwise, this makes ``abidiff`` compare the set of its
first input and its dependencies against the set of its second
input and its dependencies.
* ``list-dependencies | --ldeps``
This option lists all the dependencies of the input arguments of
``abidiff`` that are found in the directories specified by the
options ``--added-binaries-dir1`` and ``--added-binaries-dir2``
* ``--added-binaries-dir1 | --abd1`` <added-binaries-directory-1>
This option is to be used in conjunction with the
``--add-binaries1``, ``--follow-dependencies`` and
``--list-dependencies`` options. Binaries referred to by these
options, if found in the directory `added-binaries-directory-1`,
are loaded as ABI corpus and are added to the first ABI corpus group
that is to be used in the comparison.
* ``--added-binaries-dir2 | --abd2`` <added-binaries-directory-2>
This option is to be used in conjunction with the
``--add-binaries2``, ``--follow-dependencies`` and
``--list-dependencies`` options. Binaries referred to by these
options, if found in the directory `added-binaries-directory-2`,
are loaded as ABI corpus and are added to the second ABI corpus
group to be used in the comparison.
* ``--no-linux-kernel-mode``
Without this option, if abidiff detects that the binaries it is
looking at are Linux Kernel binaries (either vmlinux or modules)
then it only considers functions and variables which ELF symbols
are listed in the __ksymtab and __ksymtab_gpl sections.
With this option, abidiff considers the binary as a non-special
ELF binary. It thus considers functions and variables which are
defined and exported in the ELF sense.
* ``--kmi-whitelist | -w`` <*path-to-whitelist*>
When analyzing a Linux kernel binary, this option points to the
white list of names of ELF symbols of functions and variables
which ABI must be considered. That white list is called a "Kernel
Module Interface white list". This is because for the Kernel, we
don't talk about ``ABI``; we rather talk about the interface
between the Kernel and its module. Hence the term ``KMI`` rather
than ``ABI``.
Any other function or variable which ELF symbol are not present in
that white list will not be considered by this tool.
If this option is not provided -- thus if no white list is
provided -- then the entire KMI, that is, the set of all publicly
defined and exported functions and global variables by the Linux
Kernel binaries, is considered.
* ``--drop-private-types``
This option is to be used with the ``--headers-dir1``,
``header-file1``, ``header-file2`` and ``--headers-dir2`` options.
With this option, types that are *NOT* defined in the headers are
entirely dropped from the internal representation build by
Libabigail to represent the ABI. They thus don't have to be
filtered out from the final ABI change report because they are not
even present in Libabigail's representation.
Without this option however, those private types are kept in the
internal representation and later filtered out from the report.
This options thus potentially makes Libabigail consume less
memory. It's meant to be mainly used to optimize the memory
consumption of the tool on binaries with a lot of publicly defined
and exported types.
* ``--exported-interfaces-only``
By default, when looking at the debug information accompanying a
binary, this tool analyzes the descriptions of the types reachable
by the interfaces (functions and variables) that are visible
outside of their translation unit. Once that analysis is done, an
ABI corpus is constructed by only considering the subset of types
reachable from interfaces associated to `ELF`_ symbols that are
defined and exported by the binary. It's those final ABI Corpora
that are compared by this tool.
The problem with that approach however is that analyzing all the
interfaces that are visible from outside their translation unit
can amount to a lot of data, especially when those binaries are
applications, as opposed to shared libraries. One example of such
applications is the `Linux Kernel`_. Analyzing massive ABI
corpora like these can be extremely slow.
To mitigate that performance issue, this option allows libabigail
to only analyze types that are reachable from interfaces
associated with defined and exported `ELF`_ symbols.
Note that this option is turned on by default when analyzing the
`Linux Kernel`_. Otherwise, it's turned off by default.
* ``--allow-non-exported-interfaces``
When looking at the debug information accompanying a binary, this
tool analyzes the descriptions of the types reachable by the
interfaces (functions and variables) that are visible outside of
their translation unit. Once that analysis is done, an ABI corpus
is constructed by only considering the subset of types reachable
from interfaces associated to `ELF`_ symbols that are defined and
exported by the binary. It's those final ABI Corpora that are
compared by this tool.
The problem with that approach however is that analyzing all the
interfaces that are visible from outside their translation unit
can amount to a lot of data, especially when those binaries are
applications, as opposed to shared libraries. One example of such
applications is the `Linux Kernel`_. Analyzing massive ABI
Corpora like these can be extremely slow.
In the presence of an "average sized" binary however one can
afford having libabigail analyze all interfaces that are visible
outside of their translation unit, using this option.
Note that this option is turned on by default, unless we are in
the presence of the `Linux Kernel`_.
* ``--stat``
Rather than displaying the detailed ABI differences between
*first-shared-library* and *second-shared-library*, just display
some summary statistics about these differences.
* ``--symtabs``
Only display the symbol tables of the *first-shared-library* and
*second-shared-library*.
* ``--deleted-fns``
In the resulting report about the differences between
*first-shared-library* and *second-shared-library*, only display
the globally defined functions that got deleted from
*first-shared-library*.
* ``--changed-fns``
In the resulting report about the differences between
*first-shared-library* and *second-shared-library*, only display
the changes in sub-types of the global functions defined in
*first-shared-library*.
* ``--added-fns``
In the resulting report about the differences between
*first-shared-library* and *second-shared-library*, only display
the globally defined functions that were added to
*second-shared-library*.
* ``--deleted-vars``
In the resulting report about the differences between
*first-shared-library* and *second-shared-library*, only display
the globally defined variables that were deleted from
*first-shared-library*.
* ``--changed-vars``
In the resulting report about the differences between
*first-shared-library* and *second-shared-library*, only display
the changes in the sub-types of the global variables defined in
*first-shared-library*
* ``--added-vars``
In the resulting report about the differences between
*first-shared-library* and *second-shared-library*, only display
the global variables that were added (defined) to
*second-shared-library*.
* ``--non-reachable-types|-t``
Analyze and emit change reports for all the types of the binary,
including those that are not reachable from global functions and
variables.
This option might incur some serious performance degradation as
the number of types analyzed can be huge. However, if paired with
the ``--headers-dir{1,2}`` and/or ``header-file{1,2}`` options,
the additional non-reachable types analyzed are restricted to
those defined in public headers files, thus hopefully making the
performance hit acceptable.
Also, using this option alongside suppression specifications (by
also using the ``--suppressions`` option) might help keep the number of
analyzed types (and the potential performance degradation) in
control.
Note that without this option, only types that are reachable from
global functions and variables are analyzed, so the tool detects
and reports changes on these reachable types only.
* ``--no-added-syms``
In the resulting report about the differences between
*first-shared-library* and *second-shared-library*, do not display
added functions or variables. Do not display added functions or
variables ELF symbols either. All other kinds of changes are
displayed unless they are explicitely forbidden by other options
on the command line.
* ``--no-linkage-name``
In the resulting report, do not display the linkage names of
the added, removed, or changed functions or variables.
* ``--no-show-locs``
Do not show information about where in the *second shared library*
the respective type was changed.
* ``--show-bytes``
Show sizes and offsets in bytes, not bits. By default, sizes and
offsets are shown in bits.
* ``--show-bits``
Show sizes and offsets in bits, not bytes. This option is
activated by default.
* ``--show-hex``
Show sizes and offsets in hexadecimal base.
* ``--show-dec``
Show sizes and offsets in decimal base. This option is activated
by default.
* ``--ignore-soname``
Ignore differences in the SONAME when doing a comparison
* ``--no-show-relative-offset-changes``
Without this option, when the offset of a data member changes,
the change report not only mentions the older and newer offset,
but it also mentions by how many bits the data member changes.
With this option, the latter is not shown.
* ``--no-unreferenced-symbols``
In the resulting report, do not display change information about
function and variable symbols that are not referenced by any debug
information. Note that for these symbols not referenced by any
debug information, the change information displayed is either
added or removed symbols.
* ``--no-default-suppression``
Do not load the :ref:`default suppression specification files
<abidiff_default_supprs_label>`.
* ``--suppressions | --suppr`` <*path-to-suppressions*>
Use a :ref:`suppression specification <suppr_spec_label>` file
located at *path-to-suppressions*. Note that this option can
appear multiple times on the command line. In that case, all of
the provided suppression specification files are taken into
account.
Please note that, by default, if this option is not provided, then
the :ref:`default suppression specification files
<abidiff_default_supprs_label>` are loaded .
* ``--drop`` <*regex*>
When reading the *first-shared-library* and
*second-shared-library* ELF input files, drop the globally defined
functions and variables which name match the regular expression
*regex*. As a result, no change involving these functions or
variables will be emitted in the diff report.
* ``--drop-fn`` <*regex*>
When reading the *first-shared-library* and
*second-shared-library* ELF input files, drop the globally defined
functions which name match the regular expression *regex*. As a
result, no change involving these functions will be emitted in the
diff report.
* ``--drop-var`` <*regex*>
When reading the *first-shared-library* and
*second-shared-library* ELF input files, drop the globally defined
variables matching a the regular expression *regex*.
* ``--keep`` <*regex*>
When reading the *first-shared-library* and
*second-shared-library* ELF input files, keep the globally defined
functions and variables which names match the regular expression
*regex*. All other functions and variables are dropped on the
floor and will thus not appear in the resulting diff report.
* ``--keep-fn`` <*regex*>
When reading the *first-shared-library* and
*second-shared-library* ELF input files, keep the globally defined
functions which name match the regular expression *regex*. All
other functions are dropped on the floor and will thus not appear
in the resulting diff report.
* ``--keep-var`` <*regex*>
When reading the *first-shared-library* and
*second-shared-library* ELF input files, keep the globally defined
which names match the regular expression *regex*. All other
variables are dropped on the floor and will thus not appear in the
resulting diff report.
* ``--harmless``
In the diff report, display only the :ref:`harmless
<harmlesschangeconcept_label>` changes. By default, the harmless
changes are filtered out of the diff report keep the clutter to a
minimum and have a greater chance to spot real ABI issues.
* ``--no-harmful``
In the diff report, do not display the :ref:`harmful
<harmfulchangeconcept_label>` changes. By default, only the
harmful changes are displayed in diff report.
* ``--redundant``
In the diff report, do display redundant changes. A redundant
change is a change that has been displayed elsewhere in the
report.
* ``--no-redundant``
In the diff report, do *NOT* display redundant changes. A
redundant change is a change that has been displayed elsewhere in
the report. This option is switched on by default.
* ``--no-architecture``
Do not take architecture in account when comparing ABIs.
* ``--no-corpus-path``
Do not emit the path attribute for the ABI corpus.
* ``--fail-no-debug-info``
If no debug info was found, then this option makes the program to
fail. Otherwise, without this option, the program will attempt to
compare properties of the binaries that are not related to debug
info, like pure ELF properties.
* ``--leaf-changes-only|-l`` only show leaf changes, so don't show
impact analysis report. This option implies ``--redundant``.
The typical output of abidiff when comparing two binaries looks
like this ::
$ abidiff libtest-v0.so libtest-v1.so
Functions changes summary: 0 Removed, 1 Changed, 0 Added function
Variables changes summary: 0 Removed, 0 Changed, 0 Added variable
1 function with some indirect sub-type change:
[C]'function void fn(C&)' at test-v1.cc:13:1 has some indirect sub-type changes:
parameter 1 of type 'C&' has sub-type changes:
in referenced type 'struct C' at test-v1.cc:7:1:
type size hasn't changed
1 data member change:
type of 'leaf* C::m0' changed:
in pointed to type 'struct leaf' at test-v1.cc:1:1:
type size changed from 32 to 64 bits
1 data member insertion:
'char leaf::m1', at offset 32 (in bits) at test-v1.cc:4:1
$
So in that example the report emits information about how the data
member insertion change of "struct leaf" is reachable from
function "void fn(C&)". In other words, the report not only shows
the data member change on "struct leaf", but it also shows the
impact of that change on the function "void fn(C&)".
In abidiff parlance, the change on "struct leaf" is called a leaf
change. So the ``--leaf-changes-only --impacted-interfaces``
options show, well, only the leaf change. And it goes like this:
::
$ abidiff -l libtest-v0.so libtest-v1.so
'struct leaf' changed:
type size changed from 32 to 64 bits
1 data member insertion:
'char leaf::m1', at offset 32 (in bits) at test-v1.cc:4:1
one impacted interface:
function void fn(C&)
$
Note how the report ends by showing the list of interfaces
impacted by the leaf change.
Now if you don't want to see that list of impacted interfaces,
then you can just avoid using the ``--impacted-interface`` option.
You can learn about that option below, in any case.
* ``--impacted-interfaces``
When showing leaf changes, this option instructs abidiff to show
the list of impacted interfaces. This option is thus to be used
in addition the ``--leaf-changes-only`` option, otherwise, it's
ignored.
* ``--dump-diff-tree``
After the diff report, emit a textual representation of the diff
nodes tree used by the comparison engine to represent the changed
functions and variables. That representation is emitted to the
error output for debugging purposes. Note that this diff tree is
relevant only to functions and variables that have some sub-type
changes. Added or removed functions and variables do not have any
diff nodes tree associated to them.
* ``--no-assume-odr-for-cplusplus``
When analysing a binary originating from C++ code using `DWARF`_
debug information, libabigail assumes the `One Definition Rule`_
to speed-up the analysis. In that case, when several types have
the same name in the binary, they are assumed to all be equal.
This option disables that assumption and instructs libabigail to
actually actually compare the types to determine if they are
equal.
* ``--no-leverage-dwarf-factorization``
When analysing a binary which `DWARF`_ debug information was
processed with the `DWZ`_ tool, the type information is supposed
to be already factorized. That context is used by libabigail to
perform some speed optimizations.
This option disables those optimizations.
* ``--no-change-categorization | -x``
This option disables the categorization of changes into harmless
and harmful changes. Note that this categorization is a
pre-requisite for the filtering of changes so this option disables
that filtering. The goal of this option is to speed-up the
execution of the program for cases where the graph of changes is
huge and where the user is just interested in looking at, for
instance, leaf node changes without caring about their possible
impact on interfaces. In that case, this option would be used
along with the ``--leaf-changes-only`` one.
* ``--ctf``
When comparing binaries, extract ABI information from `CTF`_ debug
information, if present.
* ``--btf``
When comparing binaries, extract ABI information from `BTF`_ debug
information, if present.
* ``--stats``
Emit statistics about various internal things.
* ``--verbose``
Emit verbose logs about the progress of miscellaneous internal
things.
.. _abidiff_return_value_label:
Return values
=============
The exit code of the ``abidiff`` command is either 0 if the ABI of the
binaries being compared are equal, or non-zero if they differ or if
the tool encountered an error.
In the later case, the exit code is a 8-bits-wide bit field in which
each bit has a specific meaning.
The first bit, of value 1, named ``ABIDIFF_ERROR`` means there was an
error.
The second bit, of value 2, named ``ABIDIFF_USAGE_ERROR`` means there
was an error in the way the user invoked the tool. It might be set,
for instance, if the user invoked the tool with an unknown command
line switch, with a wrong number or argument, etc. If this bit is
set, then the ``ABIDIFF_ERROR`` bit must be set as well.
The third bit, of value 4, named ``ABIDIFF_ABI_CHANGE`` means the ABI
of the binaries being compared are different.
The fourth bit, of value 8, named ``ABIDIFF_ABI_INCOMPATIBLE_CHANGE``
means the ABI of the binaries compared are different in an
incompatible way. If this bit is set, then the ``ABIDIFF_ABI_CHANGE``
bit must be set as well. If the ``ABIDIFF_ABI_CHANGE`` is set and the
``ABIDIFF_INCOMPATIBLE_CHANGE`` is *NOT* set, then it means that the
ABIs being compared might or might not be compatible. In that case, a
human being needs to review the ABI changes to decide if they are
compatible or not.
Note that, at the moment, there are only a few kinds of ABI changes
that would result in setting the flag ``ABIDIFF_ABI_INCOMPATIBLE_CHANGE``.
Those ABI changes are either:
- the removal of the symbol of a function or variable that has been
defined and exported.
- the modification of the index of a member of a virtual function
table (for C++ programs and libraries).
With time, when more ABI change patterns are found to *always*
constitute incompatible ABI changes, we will adapt the code to
recognize those cases and set the ``ABIDIFF_ABI_INCOMPATIBLE_CHANGE``
accordingly. So, if you find such patterns, please let us know.
The remaining bits are not used for the moment.
.. _abidiff_usage_example_label:
Usage examples
==============
1. Detecting a change in a sub-type of a function: ::
$ cat -n test-v0.cc
1 // Compile this with:
2 // g++ -g -Wall -shared -o libtest-v0.so test-v0.cc
3
4 struct S0
5 {
6 int m0;
7 };
8
9 void
10 foo(S0* /*parameter_name*/)
11 {
12 // do something with parameter_name.
13 }
$
$ cat -n test-v1.cc
1 // Compile this with:
2 // g++ -g -Wall -shared -o libtest-v1.so test-v1.cc
3
4 struct type_base
5 {
6 int inserted;
7 };
8
9 struct S0 : public type_base
10 {
11 int m0;
12 };
13
14 void
15 foo(S0* /*parameter_name*/)
16 {
17 // do something with parameter_name.
18 }
$
$ g++ -g -Wall -shared -o libtest-v0.so test-v0.cc
$ g++ -g -Wall -shared -o libtest-v1.so test-v1.cc
$
$ ../build/tools/abidiff libtest-v0.so libtest-v1.so
Functions changes summary: 0 Removed, 1 Changed, 0 Added function
Variables changes summary: 0 Removed, 0 Changed, 0 Added variable
1 function with some indirect sub-type change:
[C]'function void foo(S0*)' has some indirect sub-type changes:
parameter 0 of type 'S0*' has sub-type changes:
in pointed to type 'struct S0':
size changed from 32 to 64 bits
1 base class insertion:
struct type_base
1 data member change:
'int S0::m0' offset changed from 0 to 32
$
2. Detecting another change in a sub-type of a function: ::
$ cat -n test-v0.cc
1 // Compile this with:
2 // g++ -g -Wall -shared -o libtest-v0.so test-v0.cc
3
4 struct S0
5 {
6 int m0;
7 };
8
9 void
10 foo(S0& /*parameter_name*/)
11 {
12 // do something with parameter_name.
13 }
$
$ cat -n test-v1.cc
1 // Compile this with:
2 // g++ -g -Wall -shared -o libtest-v1.so test-v1.cc
3
4 struct S0
5 {
6 char inserted_member;
7 int m0;
8 };
9
10 void
11 foo(S0& /*parameter_name*/)
12 {
13 // do something with parameter_name.
14 }
$
$ g++ -g -Wall -shared -o libtest-v0.so test-v0.cc
$ g++ -g -Wall -shared -o libtest-v1.so test-v1.cc
$
$ ../build/tools/abidiff libtest-v0.so libtest-v1.so
Functions changes summary: 0 Removed, 1 Changed, 0 Added function
Variables changes summary: 0 Removed, 0 Changed, 0 Added variable
1 function with some indirect sub-type change:
[C]'function void foo(S0&)' has some indirect sub-type changes:
parameter 0 of type 'S0&' has sub-type changes:
in referenced type 'struct S0':
size changed from 32 to 64 bits
1 data member insertion:
'char S0::inserted_member', at offset 0 (in bits)
1 data member change:
'int S0::m0' offset changed from 0 to 32
$
3. Detecting that functions got removed or added to a library: ::
$ cat -n test-v0.cc
1 // Compile this with:
2 // g++ -g -Wall -shared -o libtest-v0.so test-v0.cc
3
4 struct S0
5 {
6 int m0;
7 };
8
9 void
10 foo(S0& /*parameter_name*/)
11 {
12 // do something with parameter_name.
13 }
$
$ cat -n test-v1.cc
1 // Compile this with:
2 // g++ -g -Wall -shared -o libtest-v1.so test-v1.cc
3
4 struct S0
5 {
6 char inserted_member;
7 int m0;
8 };
9
10 void
11 bar(S0& /*parameter_name*/)
12 {
13 // do something with parameter_name.
14 }
$
$ g++ -g -Wall -shared -o libtest-v0.so test-v0.cc
$ g++ -g -Wall -shared -o libtest-v1.so test-v1.cc
$
$ ../build/tools/abidiff libtest-v0.so libtest-v1.so
Functions changes summary: 1 Removed, 0 Changed, 1 Added functions
Variables changes summary: 0 Removed, 0 Changed, 0 Added variable
1 Removed function:
'function void foo(S0&)' {_Z3fooR2S0}
1 Added function:
'function void bar(S0&)' {_Z3barR2S0}
$
4. Comparing two sets of binaries that are passed on the command line: ::
$ abidiff --add-binaries1=file2-v1 \
--add-binaries2=file2-v2,file2-v1 \
--added-binaries-dir1 dir1 \
--added-binaries-dir2 dir2 \
file1-v1 file1-v2
Note that the files ``file2-v1``, and ``file2-v2`` are to be
found in ``dir1`` and ``dir2`` or in the current directory.
5. Compare two libraries and their dependencies: ::
$ abidiff --follow-dependencies \
--added-binaries-dir1 /some/where \
--added-binaries-dir2 /some/where/else \
foo bar
This compares the set of binaries comprised by ``foo`` and its
dependencies against the set of binaries comprised by ``bar`` and
its dependencies.
.. _ELF: http://en.wikipedia.org/wiki/Executable_and_Linkable_Format
.. _DWARF: http://www.dwarfstd.org
.. _CTF: https://raw.githubusercontent.com/wiki/oracle/binutils-gdb/files/ctf-spec.pdf
.. _BTF: https://docs.kernel.org/bpf/btf.html
.. _ODR: https://en.wikipedia.org/wiki/One_Definition_Rule
.. _One Definition Rule: https://en.wikipedia.org/wiki/One_Definition_Rule
.. _DWZ: https://sourceware.org/dwz
.. _Linux Kernel: https://kernel.org/