Horton

Re: Build with LTO / -flto on macOS

Peter Eisentraut <peter@eisentraut.org>

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From: Peter Eisentraut <peter@eisentraut.org>
To: Wolfgang Walther <walther@technowledgy.de>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Cc: Tom Lane <tgl@sss.pgh.pa.us>, Andres Freund <andres@anarazel.de>
Date: 2024-06-03T14:32:01Z
Lists: pgsql-hackers

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

  1. Make building with LTO work on macOS

  2. Require memory barrier support.

  3. Require compiler barrier support.

  4. autoconf: Move export_dynamic determination to configure

On 03.06.24 16:22, Wolfgang Walther wrote:
> Building with clang and -flto on macOS currently fails with errors 
> similar to [1]. This is because the --export-dynamic flag is called 
> -export_dynamic [2] instead and we have not been passing this variant to 
> the linker, so far.

It's probably worth clarifying that this option is needed on macOS only 
if LTO is also enabled.  For standard (non-LTO) builds, the 
export-dynamic behavior is already the default on macOS (otherwise 
nothing in PostgreSQL would work).

I don't think we explicitly offer LTO builds as part of the make build 
system, so anyone trying this would do it sort of self-service, by 
passing additional options to configure or make.  In which case they 
might as well pass the -export_dynamic option along in the same way?

I don't mind addressing this in PG18, but I would hesitate with 
backpatching.  With macOS, it's always hard to figure out whether these 
kinds of options work the same way going versions back.