[fpc-devel] Stack dump with possible segfault

[Sven Barth]

Am 13.05.2014 21:56 schrieb "Johann Glaser" <Johann.Glaser at gmx.at>:

> > As this is true for FreePascal code (I guess), this doesn't necessarily
> > hold for external libraries as the TCL library mentioned above.
>
> News on that front: Today I investigated a duplicate key exception in
> FGL.TFPSMaps.Add(AKey: Pointer): Integer. In the current Debian package
> fp-units-rtl-2.6.4 2.6.4+dfsg-2 this seems to be compiled with looots of
> optimization and without stack frame:
>
> 0000000000001918 <FGL_TFPSMAP_$__ADD$POINTER$$LONGINT>:
>     1918:       48 81 ec 18 01 00 00    sub    $0x118,%rsp
>     191f:       48 89 9c 24 08 01 00    mov    %rbx,0x108(%rsp)
>     1926:       00
>     1927:       4c 89 a4 24 10 01 00    mov    %r12,0x110(%rsp)
>     192e:       00
>     192f:       48 89 fb                mov    %rdi,%rbx
>     1932:       49 89 f4                mov    %rsi,%r12
>
> Even GDB couldn't trace back the stack there. :-O

Code in release packages is normally compiled using -O2, which can result
in hard to follow backtraces.

Regards,
Sven
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