[fpc-pascal] Building trunk

[Florian Klämpfl]

Am 25.11.2018 um 12:20 schrieb C Western:
> On 24/11/2018 22:21, Florian Klämpfl wrote:
>> Am 24.11.2018 um 10:08 schrieb C Western:
>>> On 23/11/2018 09:50, Sven Barth via fpc-pascal wrote:
>>>> Am Fr., 23. Nov. 2018, 10:26 hat C Western <l at c-m-w.me.uk <mailto:l at c-m-w.me.uk>> geschrieben:
>>>>
>>>>      I haven't been able to build trunk i386 fpc for a couple of weeks. Is
>>>>      this supposed to be working, or have I misconfigured something? (I
>>>>      don't
>>>>      think I have changed anything.) The output is below. I don't think
>>>>      it is
>>>>      significant, but I am building on a 64 bit system, but with a 32 bit
>>>>      starting compiler. (The 64 bit build with the 64 bit starting
>>>>      compiler
>>>>      works fine.)
>>>>
>>>>
>>>> We have i386 trunk building on at least one x86_64-linux machine, so it can't be a principal problem. :/
>>>> Could you check whether it's FPC itself that segfaults or something else and if the former try to retrieve a
>>>> stacktrace, please?
>>>>
>>>> Regards,
>>>> Sven
>>>>
>>>> _______________________________________________
>>>> fpc-pascal maillist  -  fpc-pascal at lists.freepascal.org
>>>> http://lists.freepascal.org/cgi-bin/mailman/listinfo/fpc-pascal
>>> Looks like the ppc1 compiler crashes during setup:
>>>
>>> gdb) run
>>> Starting program: /home/me/fpc/trunk/fpcsrc/compiler/ppc1
>>>
>>> Program received signal SIGSEGV, Segmentation fault.
>>> 0x08068760 in INITTLS () at system.pp:543
>>> 543            case phdr^.p_type of
>>> (gdb) bt
>>> #0  0x08068760 in INITTLS () at system.pp:543
>>> #1  0x082a63fb in _FPC_PROC_START () at ./i386/si_prc.inc:105
>>> (gdb) p phdr
>>> $1 = (PPHDR) 0x8048034
>>> (gdb) p phdr^
>>> Cannot access memory at address 0x8048034
>> Can you please check what value phdr has at the crash location after applying the following patch?
>>
>> diff --git a/rtl/linux/system.pp b/rtl/linux/system.pp
>> index 0d7ed2b152..74b4592ace 100644
>> --- a/rtl/linux/system.pp
>> +++ b/rtl/linux/system.pp
>> @@ -525,6 +525,8 @@ procedure InitTLS; [public,alias:'FPC_INITTLS'];
>>       while assigned(auxp^) do
>>         inc(auxp);
>>       inc(auxp);
>> +    phdr:=nil;
>> +    phnum:=0;
>>       { now we are at the auxillary vector }
>>       while assigned(auxp^) do
>>         begin
>> _______________________________________________
>> fpc-pascal maillist  -  fpc-pascal at lists.freepascal.org
>> http://lists.freepascal.org/cgi-bin/mailman/listinfo/fpc-pascal
> 
> That gives the same value as shown above, even after applying the patch. Single stepping the code indicates that both
> variables are assigned: (Some lines deleted).

This is pretty strange then. This code is pretty simple and in general, tls initialization should be done regardless if
FPC uses it for threadvars or not. What version of Fedora are you using?