Re: Future Postgres 15 and Clang 15

On Fri, Jun 24, 2022 at 8:35 PM Fabien COELHO <coelho(at)cri(dot)ensmp(dot)fr> wrote:
> Just a note/reminder that "seawasp" has been unhappy for some days now
> because of yet another change in the unstable API provided by LLVM:

Hi Fabien,

Yeah, I've started on the changes needed for opaque pointers (that's
the change that's been generating warnings since LLVM14, and now
aborts in LLVM15), but I haven't figured out all the puzzles yet. I
will have another go at this this weekend and then post what I've got,
to show where I'm stuck.

> https://buildfarm.postgresql.org/cgi-bin/show_log.pl?nm=seawasp&dt=2022-06-23%2023%3A18%3A17
>
> llvmjit.c:1115:50: error: use of undeclared identifier 'LLVMJITCSymbolMapPair'
> LLVMOrcCSymbolMapPairs symbols = palloc0(sizeof(LLVMJITCSymbolMapPair) * LookupSetSize);
>
> llvmjit.c:1233:81: error: too few arguments to function call, expected 3, have 2
> ref_gen = LLVMOrcCreateCustomCAPIDefinitionGenerator(llvm_resolve_symbols, NULL);

Ah yes, I hadn't seen that one yet. That function grew a "Dispose"
argument, which we can just pass NULL for, at a guess:

https://github.com/llvm/llvm-project/commit/14b7c108a2bf46541efc3a5c9cbd589b3afc18e6

> The question is: should pg 15 try to be clang 15 ready? I'm afraid yes, as
> LLVM does 2 releases per year, so clang 15 should come out this Fall,
> together with pg 15. Possibly other changes will come before the
> releases:-/

OK let's try to get a patch ready first and then see what we can do.
I'm more worried about code that compiles OK but then crashes or gives
wrong query results (like the one for 9b4e4cfe) than I am about code
that doesn't compile at all (meaning no one can actually ship it!). I
think the way our two projects' release cycles work, there will
occasionally be short periods where we can't use their very latest
release, but we can try to avoid that...