On Mon, Aug 31, 2015 at 08:56:58PM +0300, Ilya Verbin wrote:
> On Mon, Aug 31, 2015 at 16:49:53 +0200, Jakub Jelinek wrote:
> > 1) Is the library backwards ABI compatible? Can you run e.g.
> > libabigail abidiff in between the unpatched and patched version?
>
> It should be in theory, and I've successfully tested an old binary with old
> libgomp plugin and with new liboffloadmic. However, `abidiff --changed-fns
> old/liboffloadmic_host.so new/liboffloadmic_host.so` prints:
>
> Functions changes summary: 0 Removed (82 filtered out), 7 Changed (21
> filtered out), 0 Added functions (1081 filtered out)
> Variables changes summary: 0 Removed (25 filtered out), 1 Changed, 0 Added
> variables (7 filtered out)
> Function symbols changes summary: 7 Removed, 76 Added function symbols not
> referenced by debug info
> Variable symbols changes summary: 22 Removed, 4 Added variable symbols not
> referenced by debug info
>
> 7 functions with some indirect sub-type change:
>
> /* Unused functions skipped. */
>
> [C]'function int __offload_offload(OFFLOAD, const char*, int, int,
> VarDesc*, VarDesc2*, int, int)' has some indirect sub-type changes:
> parameter 1 of type 'typedef OFFLOAD' has sub-type changes:
> underlying type 'OffloadDescriptor*' changed:
> in pointed to type 'struct OffloadDescriptor':
> type size changed from 2240 to 2368 bits
> 9 data member insertions:
> /* ... */
>
> [C]'function void __offload_register_image()' has some indirect sub-type
> changes:
> return type changed:
> type name changed from 'void' to 'bool'
> type size changed from 0 to 8 bits
E.g. this is an ABI change, if e.g. anything in the plugin will call
__offload_register_image and check for return value (i.e. expect the new
versioN), but actually at runtime link against the old one, it will
misbehave.
> abidiff: ../../src/abg-comparison.cc:10731: virtual void
> abigail::comparison::fn_parm_diff::report(std::ostream&, const string&)
> const: Assertion `get_type_diff() && get_type_diff()->to_be_reported()'
> failed.
> Aborted (core dumped)
>
> > 2) the *.map changes look wrong, when adding symbols to a symbol versioned
> > shared library, new symbols shouldn't be added to existing symbol
> > version, but to a new symbol version (so e.g. MYO_1.0.1 (or MYO_1.1)
> > and COI_1.0.1 (or COI_1.1))
>
> I agree, but this is what I can't change - these files are copied from real
> COI/
> MYO libraries, therefore the emulator (fake COI/MYO libs) must have the same
> versions as the real libs.
If that change is already cast into stone, there is nothing we can do, but
can you talk to the library maintainers that they add new symbols to
different symbol version next time at least?
Jakub
