Provided by: abigail-tools_1.0~rc3-1_amd64 
NAME
abidiff - compare ABIs of ELF files
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.
For a comprehensive ABI change report that includes changes about function and variable sub-types, the
two input shared libraries must be accompanied with their debug information in DWARF format. Otherwise,
only ELF symbols that were added or removed are reported.
INVOCATION
abidiff [options] <first-shared-library> <second-shared-library>
OPTIONS
• --help | -h
Display a short help about the command and exit.
• --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.
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.
• --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.
• --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.
• --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.
• --suppressions | --suppr <path-to-suppressions>
Use a suppression specification file located at path-to-suppressions. Note that this option can
appear multiple times on the command line; all the suppression specification files are then taken
into account.
• --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 harmless changes. By default, the harmless changes are
filtered out of the diff report keep the clutter to a minimum and have a greater change to spot real
ABI issues.
• --no-harmful
In the diff report, do not display the harmful 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.
• --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.
• --stats
Emit statistics about various internal things.
• --verbose
Emit verbose logs about the progress of miscellaneous internal things.
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.
The remaining bits are not used for the moment.
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}
$
AUTHOR
Dodji Seketeli
COPYRIGHT
2014, Red Hat, Inc.
March 10, 2016 ABIDIFF(1)