• --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 | -kaw <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

• --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 default suppression specification files.

• --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. 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 default suppression specification files 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 harmless 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 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.

• --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

• --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.

• 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).

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.

• --help | -h

  Display a short help about the command and exit.

• –version | -v

  Display the version of the program and exit.

• --debug-info-pkg1 | --d1 <path>

  For cases where the debug information for package1 is split out into a separate file, tells abipkgdiff where to find that separate debug information package.

  Note that the debug info for package1 can have been split into several different debug info packages. In that case, several instances of this options can be provided, along with those several different debug info packages.

• --debug-info-pkg2 | --d2 <path>

  For cases where the debug information for package2 is split out into a separate file, tells abipkgdiff where to find that separate debug information package.

  Note that the debug info for package2 can have been split into several different debug info packages. In that case, several instances of this options can be provided, along with those several different debug info packages.

• --devel-pkg1 | --devel1 <path>

  Specifies where to find the Development Package associated with the first package to be compared. That Development Package at path should at least contain header files in which public types exposed by the libraries (of the first package to be compared) are defined. When this option is provided, the tool filters out reports about ABI changes to types that are NOT defined in these header files.

• --devel-pkg2 | --devel2 <path>

  Specifies where to find the Development Package associated with the second package to be compared. That Development Package at path should at least contains header files in which public types exposed by the libraries (of the second package to be compared) are defined. When this option is provided, the tool filters out reports about ABI changes to types that are NOT defined in these header files.

• --drop-private-types

  This option is to be used with the --devel-pkg1 and --devel-pkg2 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.

• --dso-only

  Compare ELF files that are shared libraries, only. Do not compare executable files, for instance.

• --private-dso

  By default, abipkgdiff does not compare DSOs that are private to the RPM package. A private DSO is a DSO which SONAME is NOT advertised in the “provides” property of the RPM.

  This option instructs abipkgdiff to also compare DSOs that are NOT advertised in the “provides” property of the RPM.

  Please note that the fact that (by default) abipkgdiff skips private DSO is a feature that is available only for RPMs, at the moment. We would happily accept patches adding that feature for other package formats.

• --leaf-changes-only|-l only show leaf changes, so don’t show impact analysis report. This option implies --redundant

  The typical output of abipkgdiff and abidiff when comparing two binaries, that we shall call full impact report, 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 (and abipkgdiff) 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 up by showing the list of interfaces impacted by the leaf change. That’s the effect of the additional --impacted-interfaces option.

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.

Please note that when comparing two Linux Kernel packages, it’s this leaf changes report that is emitted, by default. The normal so-called full impact report can be emitted with the option --full-impact which is documented later below.

• --impacted-interfaces

  When showing leaf changes, this option instructs abipkgdiff to show the list of impacted interfaces. This option is thus to be used in addition to the --leaf-changes-only option, or, when comparing two Linux Kernel packages. Otherwise, it’s simply ignored.

• --full-impact|-f

  When comparing two Linux Kernel packages, this function instructs abipkgdiff to emit the so-called full impact report, which is the default report kind emitted by the abidiff tool:

$ 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
$

• --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 --devel-pkg{1,2} options, the additional non-reachable types analyzed are restricted to those defined in the public headers files carried by the referenced development packages, 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.

• --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.

• --redundant

• --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 chance to spot real ABI issues.

• --no-linkage-name

  In the resulting report, do not display the linkage names of the added, removed, or changed functions or variables.

• --no-added-syms

  Do not show the list of functions, variables, or any symbol that was added.

• --no-added-binaries

  Do not show the list of binaries that got added to the second package.

  Please note that the presence of such added binaries is not considered like an ABI change by this tool; as such, it doesn’t have any impact on the exit code of the tool. It does only have an informational value. Removed binaries are, however, considered as an ABI change.

• --no-abignore

  Do not search the package for the presence of suppression files.

• --no-parallel

  By default, abipkgdiff will use all the processors it has available to execute concurrently. This option tells it not to extract packages or run comparisons in parallel.

• --no-default-suppression

  Do not load the default suppression specification files.

• --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. In that case, all of the suppression specification files are taken into account.

  Please note that, by default, if this option is not provided, then the default suppression specification files are loaded .

• --linux-kernel-abi-whitelist | -w <path-to-whitelist>

  When comparing two Linux kernel RPM packages, this option points to the white list of names of ELF symbols of functions and variables that must be compared for ABI changes. That white list is called a “Linux kernel ABI white list”.

  Any other function or variable which ELF symbol are not present in that white list will not be considered by the ABI comparison process.

  If this option is not provided – thus if no white list is provided – then the ABI of all publicly defined and exported functions and global variables by the Linux Kernel binaries are compared.

  Please note that if a white list package is given in parameter, this option handles it just fine, like if the –wp option was used.

• --wp <path-to-whitelist-package>

  When comparing two Linux kernel RPM packages, this option points an RPM package containining several white lists of names of ELF symbols of functions and variables that must be compared for ABI changes. Those white lists are called “Linux kernel ABI white lists”.

  From the content of that white list package, this program then chooses the appropriate Linux kernel ABI white list to consider when comparing the ABI of Linux kernel binaries contained in the Linux kernel packages provided on the command line.

  That choosen Linux kernel ABI white list contains the list of names of ELF symbols of functions and variables that must be compared for ABI changes.

  Any other function or variable which ELF symbol are not present in that white list will not be considered by the ABI comparison process.

  Note that this option can be provided twice (not mor than twice), specifying one white list package for each Linux Kernel package that is provided on the command line.

  If this option is not provided – thus if no white list is provided – then the ABI of all publicly defined and exported functions and global variables by the Linux Kernel binaries are compared.

• --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-show-locs

• --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.

• --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.

• --show-identical-binaries

• --fail-no-dbg

  Make the program fail and return a non-zero exit code if couldn’t read any of the debug information that comes from the debug info packages that were given on the command line. If no debug info package were provided on the command line then this option is not active.

  Note that the non-zero exit code returned by the program as a result of this option is the constant ABIDIFF_ERROR. To know the numerical value of that constant, please refer to the exit code documentation.

• --keep-tmp-files

  Do not erase the temporary directory files that are created during the execution of the tool.

• --verbose

  Emit verbose progress messages.

• --self-check

  This is used to test the underlying Libabigail library. When in used, the command expects only on input package, along with its associated debug info packages. The command then compares each binary inside the package against its own ABIXML representation. The result of the comparison should yield the empty set if Libabigail behaves correctly. Otherwise, it means there is an issue that ought to be fixed. This option is used by people interested in Libabigail development for regression testing purposes. Here is an example of the use of this option:

$ abipkgdiff --self-check --d1 mesa-libGLU-debuginfo-9.0.1-3.fc33.x86_64.rpm  mesa-libGLU-9.0.1-3.fc33.x86_64.rpm


 ==== SELF CHECK SUCCEEDED for 'libGLU.so.1.3.1' ====
$

• --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.

• --ctf

•

--btf

• --help | -h

  Display a short help about the command and exit.

• --version | -v

  Display the version of the program and exit.

• --verbose

  Display some verbose messages while executing.

• --debug-info-dir1 | --d1 <di-path1>

  For cases where the debug information for the binaries of the first Linux kernel is split out into separate files, tells kmidiff where to find those separate debug information files.

  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.

• --debug-info-dir2 | --d2 <di-path2>

  Like --debug-info-dir1, this options tells kmidiff where to find the split debug information for the binaries of the second Linux kernel.

• --vmlinux1 | --l1 <path-to-first-vmlinux>

  Sets the path to the first vmlinux binary to consider. This has to be the uncompressed vmlinux binary compiled with debug info.

• --vmlinux2 | --l2 <path-to-first-vmlinux>

  Sets the path to the second vmlinux binary to consider. This has to be the uncompressed vmlinux binary compiled with debug info.

• --kmi-whitelist | -w <path-to-interface-whitelist>

  Set the path to the white list of interfaces to compare while comparing the Kernel Module Interface of the first kernel against the one of the second kernel.

  If this option is not provided, all the exported interfaces of the two kernels are compared. That takes a lot of times and is not necessarily meaningful because many interface are probably meant to see their reachable types change.

  So please, make sure you always use this option unless you really know what you are doing.

• --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. 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 default suppression specification files are loaded .

• --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.

• --ctf

  Extract ABI information from CTF debug information, if present, in the Kernel and Modules.

• --btf

  Extract ABI information from BTF debug information, if present, in the Kernel and Modules.

• --impacted-interfaces | -i

  Tell what interfaces got impacted by each individual ABI change.

• --full-impact | -f

  Emit a change report that shows the full impact of each change on exported interfaces. This is the default kind of report emitted by tools like abidiff or abipkgdiff.

• --exported-interfaces-only

  When using this option, this tool analyzes the descriptions of the types reachable by the interfaces (functions and variables) associated with ELF symbols that are defined and exported by the Linux Kernel.

  Otherwise, the tool also has the ability to analyze the descriptions of the types reachable by the interfaces associated with ELF symbols that are visible outside their translation unit. This later possibility is however much more resource intensive and results in much slower operations.

  That is why this option is enabled by default.

• --allow-non-exported-interfaces

  When using this option, 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 that final ABI corpus which is compared against another one.

  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, leading to very slow operations.

  Note that this option is turned off by default.

• --show-bytes

  Show sizes and offsets in bytes, not bits. This option is activated by default.

• --show-bits

  Show sizes and offsets in bits, not bytes. By default, sizes and offsets are shown in bytes.

• --show-hex

  Show sizes and offsets in hexadecimal base. This option is activated by default.

• --show-dec

  Show sizes and offsets in decimal base.

• --help | -h

  Display a short help about the command and exit.

• --version | -v

  Display the version of the program and exit.

• --abixml-version

  Display the version of the ABIXML format emitted by this program and exit.

• --add-binaries <bin1,bin2,…>

  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-dir option, then load the ABI corpus of the binary and add it to a set of ABI corpora (called a ABI Corpus Group) made of the binary denoted by the Argument of abidw. That corpus group is then serialized out.

• --follow-dependencies

  For each dependency of the input binary of abidw, if it is found in the directory specified by the --added-binaries-dir option, then construct an ABI corpus out of the dependency and add it to a set of ABI corpora (called an ABI Corpus Group) along with the ABI corpus of the input binary of the program. The ABI Corpus Group is then serialized out.

• --list-dependencies

  For each dependency of the input binary of``abidw``, if it’s found in the directory specified by the --added-binaries-dir option, then the name of the dependency is printed out.

• --added-binaries-dir | --abd <dir-path>

  This option is to be used in conjunction with the --add-binaries, the --follow-dependencies or the --list-dependencies option. Binaries listed as arguments of the --add-binaries option or being dependencies of the input binary in the case of the --follow-dependencies option and found in the directory <dir-path> are going to be loaded as ABI corpus and added to the set of ABI corpora (called an ABI corpus group) built and serialized.

• --debug-info-dir | -d <dir-path>

  In cases where the debug info for path-to-elf-file is in a separate file that is located in a non-standard place, this tells abidw where to look for that debug info file.

  Note that dir-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, abidw will potentially look into all those root directories to find the split debug info for the elf file.

  Note that this option is not mandatory for split debug information installed by your system’s package manager because then abidw knows where to find it.

• --out-file <file-path>

  This option instructs abidw to emit the XML representation of path-to-elf-file into the file file-path, rather than emitting it to its standard output.

• --noout

  This option instructs abidw to not emit the XML representation of the ABI. So it only reads the ELF and debug information, builds the internal representation of the ABI and exits. This option is usually useful for debugging purposes.

• --no-corpus-path

  Do not emit the path attribute for the ABI corpus.

• --suppressions | suppr <path-to-suppression-specifications-file>

  Use a suppression specification file located at path-to-suppression-specifications-file. 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. ABI artifacts matched by the suppression specifications are suppressed from the output of this tool.

• --kmi-whitelist | -kaw <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 written out. That white list is called a ” Kernel Module Interface white list”. This is because for the Kernel, we don’t talk about the 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 the KMI writing process.

  If this option is not provided – thus if no white list is provided – then the entire KMI, that is, all publicly defined and exported functions and global variables by the Linux Kernel binaries is emitted.

• --linux-tree | --lt

  Make abidw to consider the input path as a path to a directory containing the vmlinux binary as several kernel modules binaries. In that case, this program emits the representation of the Kernel Module Interface (KMI) on the standard output.

  Below is an example of usage of abidw on a Linux Kernel tree.

  First, checkout a Linux Kernel source tree and build it. Then install the kernel modules in a directory somewhere. Copy the vmlinux binary into that directory too. And then serialize the KMI of that kernel to disk, using abidw:

$ git clone git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
$ cd linux && git checkout v4.5
$ make allyesconfig all
$ mkdir build-output
$ make INSTALL_MOD_PATH=./build-output modules_install
$ cp vmlinux build-output/modules/4.5.0
$ abidw --linux-tree build-output/modules/4.5.0 > build-output/linux-4.5.0.kmi

•

--headers-dir | --hd <headers-directory-path-1>

Specifies where to find the public headers of the binary that the tool has to consider. The tool will thus filter out types that are not defined in public headers.

Note that several public header directories can be specified for the binary to consider. In that case the --header-dir option should be present several times on the command line, like in the following example:

$ abidw --header-dir /some/path       \


        --header-dir /some/other/path \


        binary > binary.abi

• --header-file | --hf <header-file-path>

  Specifies where to find one of the public headers of the abi file that the tool has to consider. The tool will thus filter out types that are not defined in public headers.

• --drop-private-types

  This option is to be used with the --headers-dir and/or header-file 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 and will not end up in the abi XML file.

• --no-elf-needed

  Do not include the list of DT_NEEDED dependency names in the corpus.

• --drop-undefined-syms

  With this option functions or variables for which the (exported) ELF symbol is undefined are dropped from the internal representation build by Libabigail to represent the ABI and will not end up in the abi XML file.

• --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 that final ABI corpus which textual representation is saved as ABIXML.

  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 that final ABI corpus which textual representation is saved as ABIXML.

  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.

• --no-linux-kernel-mode

  Without this option, if abipkgiff 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, abipkgdiff considers the binary as a non-special ELF binary. It thus considers functions and variables which are defined and exported in the ELF sense.

• --check-alternate-debug-info <elf-path>

  If the debug info for the file elf-path contains a reference to an alternate debug info file, abidw checks that it can find that alternate debug info file. In that case, it emits a meaningful success message mentioning the full path to the alternate debug info file found. Otherwise, it emits an error code.

• --no-show-locs

• --no-parameter-names

  In the emitted ABI representation, do not show names of function parameters, just the types.

• --no-write-default-sizes

  In the XML ABI representation, do not write the size-in-bits for pointer type definitions, reference type definitions, function declarations and function types when they are equal to the default address size of the translation unit. Note that libabigail before 1.8 will not set the default size and will interpret types without a size-in-bits attribute as zero sized.

• --type-id-style <sequence``|``hash>

  This option controls how types are idenfied in the generated XML files. The default sequence style just numbers (with type-id- as prefix) the types in the order they are encountered. The hash style uses a (stable, portable) hash of libabigail’s internal type names and is intended to make the XML files easier to diff.

• --check-alternate-debug-info-base-name <elf-path>

  Like --check-alternate-debug-info, but in the success message, only mention the base name of the debug info file; not its full path.

• --load-all-types

  By default, libabigail (and thus abidw) only loads types that are reachable from functions and variables declarations that are publicly defined and exported by the binary. So only those types are present in the output of abidw. This option however makes abidw load all the types defined in the binaries, even those that are not reachable from public declarations.

• --abidiff

• --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.

• --ctf

  Extract ABI information from CTF debug information, if present in the given object.

• --annotate

• --stats

  Emit statistics about various internal things.

• --verbose

  Emit verbose logs about the progress of miscellaneous internal things.

1.

Emitting an ABIXML representation of a binary:

$ abidw binary > binary.abi

2.

Emitting an ABIXML representation of a set of binaries specified on the command line:

$ abidw --added-binaries=bin1,bin2,bin3  \


        --added-binaries-dir /some/where \


        binary > binaries.abi

Note that the binaries bin1, bin2 and bin3 are to be found in the directory /some/where. A representation of the ABI of the set of binaries binary, bin1, bin2 and bin3 called an ABI corpus group is serialized in the file binaries.abi.

3.

Emitting an ABIXML representation of a binary and its dependencies:

$ abidw --follow-dependencies              \


        --added-binaries-dir /some/where   \


        binary > binary.abi

Note that only the dependencies that are found in the directory /some/where are analysed. Their ABIs, along with the ABI the binary named binary are represented as an ABI corpus group and serialized in the file binary.abi, in the ABIXML format.

• --help

  Display a short help about the command and exit.

• –version | -v

  Display the version of the program and exit.

• --list-undefined-symbols | -u

  Display the list of undefined symbols of the application and exit.

• --show-base-names | -b

  In the resulting report emitted by the tool, this option makes the application and libraries be referred to by their base names only; not by a full absolute name. This can be useful for use in scripts that wants to compare names of the application and libraries independently of what their directory names are.

• --app-debug-info-dir | --appd <path-to-app-debug-info-directory>

  Set the path to the directory under which the debug information of the application is supposed to be laid out. This is useful for application binaries for which the debug info is in a separate set of files.

• --lib-debug-info-dir1 | --libd1 <path-to-lib1-debug-info>

  Set the path to the directory under which the debug information of the first version of the shared library is supposed to be laid out. This is useful for shared library binaries for which the debug info is in a separate set of files.

• --lib-debug-info-dir2 | --libd2 <path-to-lib1-debug-info>

  Set the path to the directory under which the debug information of the second version of the shared library is supposed to be laid out. This is useful for shared library binaries for which the debug info is in a separate set of files.

• --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.

• --no-show-locs

• --ctf

  When comparing binaries, extract ABI information from CTF debug information, if present.

• --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.

• --ignore-soname

  Ignore differences in the SONAME when doing a comparison

• --weak-mode

  This triggers the weak mode of abicompat. In this mode, only one version of the library is required. That is, abicompat is invoked like this:

abicompat --weak-mode <the-application> <the-library>

Note that the --weak-mode option can even be omitted if only one version of the library is given, along with the application; in that case, abicompat automatically switches to operate in weak mode:

abicompat <the-application> <the-library>

In this weak mode, the types of functions and variables exported by the library and consumed by the application (as in, the symbols of the these functions and variables are undefined in the application and are defined and exported by the library) are compared to the version of these types as expected by the application. And if these two versions of types are different, abicompat tells the user what the differences are.

In other words, in this mode, abicompat checks that the types of the functions and variables exported by the library mean the same thing as what the application expects, as far as the ABI is concerned.

Note that in this mode, abicompat doesn’t detect exported functions or variables (symbols) that are expected by the application but that are removed from the library. That is why it is called weak mode.

•

Detecting a possible ABI incompatibility in a new shared library version:

$ cat -n test0.h


     1  struct foo


     2  {


     3    int m0;


     4


     5    foo()


     6      : m0()


     7    {}


     8  };


     9


    10  foo*


    11  first_func();


    12


    13  void


    14  second_func(foo&);


    15


    16  void


    17  third_func();
$
$ cat -n test-app.cc


     1  // Compile with:


     2  //  g++ -g -Wall -o test-app -L. -ltest-0 test-app.cc


     3


     4  #include "test0.h"


     5


     6  int


     7  main()


     8  {


     9    foo* f = first_func();


    10    second_func(*f);


    11    return 0;


    12  }
$
$ cat -n test0.cc


     1  // Compile this with:


     2  //  g++ -g -Wall -shared -o libtest-0.so test0.cc


     3


     4  #include "test0.h"


     5


     6  foo*


     7  first_func()


     8  {


     9    foo* f = new foo();


    10    return f;


    11  }


    12


    13  void


    14  second_func(foo&)


    15  {


    16  }


    17


    18  void


    19  third_func()


    20  {


    21  }
$
$ cat -n test1.h


     1  struct foo


     2  {


     3    int  m0;


     4    char m1; /* <-- a new member got added here! */


     5


     6    foo()


     7    : m0(),


     8      m1()


     9    {}


    10  };


    11


    12  foo*


    13  first_func();


    14


    15  void


    16  second_func(foo&);


    17


    18  void


    19  third_func();
$
$ cat -n test1.cc


     1  // Compile this with:


     2  //  g++ -g -Wall -shared -o libtest-1.so test1.cc


     3


     4  #include "test1.h"


     5


     6  foo*


     7  first_func()


     8  {


     9    foo* f = new foo();


    10    return f;


    11  }


    12


    13  void


    14  second_func(foo&)


    15  {


    16  }


    17


    18  /* Let's comment out the definition of third_func()


    19     void


    20     third_func()


    21     {


    22     }


    23  */
$

$ g++ -g -Wall -shared -o libtest-0.so test0.cc
$ g++ -g -Wall -shared -o libtest-1.so test1.cc

$ g++ -g -Wall -o test-app -L. -ltest-0.so test-app.cc

$ abicompat test-app libtest-0.so libtest-1.so
ELF file 'test-app' might not be ABI compatible with 'libtest-1.so' due to differences with 'libtest-0.so' below:
Functions changes summary: 0 Removed, 2 Changed, 0 Added functions
Variables changes summary: 0 Removed, 0 Changed, 0 Added variable
2 functions with some indirect sub-type change:


  [C]'function foo* first_func()' has some indirect sub-type changes:


    return type changed:


      in pointed to type 'struct foo':


        size changed from 32 to 64 bits


        1 data member insertion:


          'char foo::m1', at offset 32 (in bits)


  [C]'function void second_func(foo&)' has some indirect sub-type changes:


    parameter 0 of type 'foo&' has sub-type changes:


      referenced type 'struct foo' changed, as reported earlier
$

$ abicompat --weak-mode test-app libtest-1.so
functions defined in library


    'libtest-1.so'
have sub-types that are different from what application


    'test-app'
expects:


  function foo* first_func():


    return type changed:


      in pointed to type 'struct foo':


        size changed from 32 to 64 bits


        1 data member insertion:


          'char foo::m1', at offset 32 (in bits)
$

• --help

  Display a short help message and exits.

• –version | -v

  Display the version of the program and exit.

• --debug-info-dir <path>

  When reading an ELF input file which debug information is split out into a separate file, this options tells abilint where to find that separate debug information file.

  Note that 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.

• --diff

  For XML inputs, perform a text diff between the input and the memory model saved back to disk. This can help to spot issues in the handling of the XML format by the underlying Libabigail library.

• --noout

  Do not display anything on standard output. The return code of the command is the only way to know if the command succeeded.

• --suppressions | suppr <path-to-suppression-specifications-file>

  Use a suppression specification file located at path-to-suppression-specifications-file. 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. ABI artifacts matched by the suppression specifications are suppressed from the output of this tool.

• --headers-dir | --hd <headers-directory-path-1>

  Specifies where to find the public headers of the first shared library that the tool has to consider. The tool will thus filter out types that are not defined in public headers.

• --header-file | --hf <header-file-path>

  Specifies where to find one of the public headers of the abi file that the tool has to consider. The tool will thus filter out types that are not defined in public headers.

• --stdin | --

  Read the input content from standard input.

• --tu

  Expect the input XML to represent a single translation unit.

• --ctf

  Extract ABI information from CTF debug information, if present in the given object.

• --help | -h

  Display a short help about the command and exit.

• --dry-run

  Don’t actually perform the ABI comparison. Details about what is going to be done are emitted on standard output.

• --debug

  Emit debugging messages about the execution of the program. Details about each method invocation, including input parameters and returned values, are emitted.

• --traceback

  Show traceback when an exception raised. This is useful for developers of the tool itself to know more exceptional errors.

• --server <URL>

  Specifies the URL of the Koji XMLRPC service the tool talks to. The default value of this option is http://koji.fedoraproject.org/kojihub.

• --topurl <URL>

  Specifies the URL of the package store the tool downloads RPMs from. The default value of this option is https://kojipkgs.fedoraproject.org.

• --from <distro>

  Specifies the name of the baseline Fedora distribution in which to find the first build that is used for comparison. The distro value can be any valid value of the RPM macro %{?dist} for Fedora, for example, fc4, fc23, fc25.

• --to <distro>

  Specifies the name of the Fedora distribution in which to find the build that is compared against the baseline specified by option --from. The distro value could be any valid value of the RPM macro %{?dist} for Fedora, for example, fc4, fc23.

• --all-subpackages

  Instructs the tool to also compare the ABI of the binaries in the sub-packages of the packages specified.

• --dso-only

  Compares the ABI of shared libraries only. If this option is not provided, the tool compares the ABI of all ELF binaries found in the packages.

• --suppressions <path-to-suppresions>

  Use a suppression specification file located at path-to-suppressions.

• --no-default-suppression

  Do not load the default suppression specification files.

• --no-devel-pkg

  Do not take associated development packages into account when performing the ABI comparison. This makes the tool report ABI changes about all types that are reachable from functions and global variables which symbols are defined and publicly exported in the binaries being compared, even if those types are not defined in public header files available from the packages being compared.

• --show-identical-binaries

• --abipkgdiff <path/to/abipkgdiff>

  Specify an alternative abipkgdiff instead of the one installed in system.

• --clean-cache-before

  Clean cache before ABI comparison.

• --clean-cache-after

  Clean cache after ABI comparison.

• --clean-cache

  If you want to clean cache both before and after ABI comparison, --clean-cache is the convenient way for you to save typing of two options at same time.

1.

Compare the ABI of binaries in a local package against the ABI of the latest stable package in Fedora 23.

Suppose you have built just built the httpd package and you want to compare the ABI of the binaries in this locally built package against the ABI of the binaries in the latest http build from Fedora 23. The command line invocation would be:

$ fedabipkgdiff --from fc23 ./httpd-2.4.18-2.fc24.x86_64.rpm

2.

Compare the ABI of binaries in two local packages.

Suppose you have built two versions of package httpd, and you want to see what ABI differences between these two versions of RPM files. The command line invocation would be:

$ fedabipkgdiff path/to/httpd-2.4.23-3.fc23.x86_64.rpm another/path/to/httpd-2.4.23-4.fc24.x86_64.rpm

All what fedabipkgdiff does happens on local machine without the need of querying or downloading RPMs from Koji.

3.

Compare the ABI of binaries in the latest build of the httpd package in Fedora 23 against the ABI of the binaries in the latest build of the same package in 24.

In this case, note that neither of the two packages are available locally. The tool is going to talk with the Fedora Build System, determine what the versions and releases of the latest packages are, download them and perform the comparison locally. The command line invocation would be:

$ fedabipkgdiff --from fc23 --to fc24 httpd

4.

Compare the ABI of binaries of two builds of the httpd package, designated their versions and releases.

If we want to do perform the ABI comparison for all the processor architectures supported by Fedora the command line invocation would be:

$ fedabipkgdiff httpd-2.8.14.fc23 httpd-2.8.14.fc24

But if we want to perform the ABI comparison for a specific architecture, say, x86_64, then the command line invocation would be:

$ fedabipkgdiff httpd-2.8.14.fc23.x86_64 httpd-2.8.14.fc24.x86_64

5.

If the use wants to also compare the sub-packages of a given package, she can use the –all-subpackages option. The first command of the previous example would thus look like:

$ fedabipkgdiff --all-subpackages httpd-2.8.14.fc23 httpd-2.8.14.fc24

changed_enumerators = LAST_ENUMERATORS0, LAST_ENUMERATOR1

changed_enumerators_regexp = .*_MAX$, .*_LAST$, .*_NUM$, .*_NBITS$

$ cat -n test1-v0.cc


     1  // A forward declaration for a type considered to be opaque to


     2  // function foo() below.


     3  struct opaque_type;


     4


     5  // This function cannot touch any member of opaque_type.  Hence,


     6  // changes to members of opaque_type should not impact foo, as far as


     7  // ABI is concerned.


     8  void


     9  foo(opaque_type*)


    10  {


    11  }


    12


    13  struct opaque_type


    14  {


    15    int member0;


    16    char member1;


    17  };
$