free(): double free detected in tcache 2

[Johan]

On Tuesday, 24 August 2021 at 06:04:12 UTC, workman wrote:
> On Monday, 23 August 2021 at 23:25:19 UTC, max haughton wrote:
>>
>> You need to break, then set the ignore count, then `info 
>> breakpoints` (something like you that) will still give you the 
>> hit count for that breakpoint
>
>
> Thanks for the tips,
>
>
> ```sh
> Num     Type           Disp Enb Address            What
> 1       breakpoint     keep y   0x00000000004b0f90 
> <_d_dso_registry>
> 	breakpoint already hit 3 times
> ```
>
> without lto
>
> ```sh
> Num     Type           Disp Enb Address            What
> 1       breakpoint     keep y   0x000000000052ece0 
> <_d_dso_registry>
> 	breakpoint already hit 2 times
>
> ```

OK, so indeed it is what I thought: with LTO _d_dso_registry is 
called too often.
The function does initialization or deinit (it is a 'toggle' 
operation).

1st call:  initialization
2nd call:  deinitialization
3rd call:  initialization, but here the struct passed probably 
contains something that triggers a second free call on a pointer 
that was not nulled maybe?  Regardless, this third call should 
not happen.

Which linker is used in the LTO case? ld.bfd, ld.gold, ld.lld ?
(`ldc2 -v ...` one of the last lines is the C compiler invocation 
for linking; check for "-fuse-ld="; if it is not there then just 
`ld` is used, check `ld --version`)

Probably the same as this bug: 
https://github.com/ldc-developers/ldc/issues/3786

-Johan