[avr-gcc-list] [patch, avr-libc] Fix atexit.c

[Georg-Johann Lay]

atexit.c has several issues which are fixed by the patch below:


i)
Issuance of calls to functions as registered by atexit() is located in section 
.fini6a.  As the current linker description does not handle that section it's 
treated as orphan and located conflicting with other sections:

$ avr-gcc main.c -mmcu=atmega128
$INSTALL/lib/gcc/avr/$VERSION/../../../../avr/bin/ld: section .fini6a loaded at 
[00000390,000003b7] overlaps section .data loaded at [00000390,00000395]
collect2: error: ld returned 1 exit status

The patch moves that code to .fini7 so that atexit functions are sequenced 
before static destructors which is closest to C++ spec.


ii)
__atexit_fini is not naked thus will crash the program as it is returning.



iii)
In order to arrange the hypothetical case that the code generated by 
atexit_fini would need a frame it's now in a proper (non-naked) function called 
by now naked atexit_fini.


iv)
Except atexit, nothing in atexit.c needs to be global --> make static.


Even though atexit is exotic in non-hosted contexts it's nice to see it 
working, e.g. to reduce testsuite fallout.


Johann

        * libc/stdlib/atexit.c (__atexit_fini): Rename to...
        (atexit_fini): ...this.  Make static, naked, and used.
        Move to section .fini7.  Outsource worker code to...
        (atexit_finido): ...this new function.
        (atexit_p): Renamed from __atexit_p.  Make static.

atexit.diff
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