[Bug target/55243] STAMP variable is not defined in t-avr

["gjl at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55243

--- Comment #29 from Georg-Johann Lay <gjl at gcc dot gnu.org> 2012-12-17 22:53:42 UTC ---
(In reply to comment #24)
>> What I don't understand is what is bad with Rolf's proposal of defining STAMP?
> 
> We simply don't need to stamp anything for the gnattools.
> 
>> Stamping is not that unusual in the build process.  Up to now it was not
>> needed, but is it that critical to set STAMP like proposed above?
> 
> Well, building the gnattools works flawlessly for all targets except for AVR,

That argument doues not count, IMO.

Almost nothing in GCC was added without precedent: Features were added because
backend X needed them or frontend Y needed them.  To reject an extension just
because only one target needs it, is not an convincing argument.

It's still not known why the ada / gnat stuff rebuilds stuff already there a
sectons time and at a stage ada / gnat don't expect such a build.

Throwing out the need of STAMP works, but it does not answer the question why
ada does things it does not expect at a stage it does not expect.

(In reply to comment #26)

>> There are other backends like x86 and mips that use STAMP in their t-snip, so
>> I wonder how you can conclude that ada does not include code that might 
>> require STAMP?
>
>I didn't say that though, rather that we don't need STAMP for the gnattools.

If I understand correctly, someone familiar with the gnat build machiney and
philosophy might want to find out why it performs a mistimed rebuild of things
that are elready supposed to be there?  

BTW, avr/t-multilib cannot be generated from scratch in the build directory
because it is included in Makefile.  The dependencies in
gcc_update:files_and_dependencies() look reasonable.