public inbox for libstdc++@gcc.gnu.org
 help / color / mirror / Atom feed
From: Florian Weimer <fweimer@redhat.com>
To: Patrick Palka via Gcc-patches <gcc-patches@gcc.gnu.org>
Cc: Patrick Palka <ppalka@redhat.com>,  libstdc++@gcc.gnu.org
Subject: Re: [PATCH 2/2] libstdc++: Move stream initialization into compiled library [PR44952]
Date: Fri, 04 Nov 2022 17:57:12 +0100	[thread overview]
Message-ID: <87eduizmhj.fsf@oldenburg.str.redhat.com> (raw)
In-Reply-To: <20221104150525.2968778-2-ppalka@redhat.com> (Patrick Palka via Gcc-patches's message of "Fri, 4 Nov 2022 11:05:25 -0400")

* Patrick Palka via Gcc-patches:

> This patch moves the global object for constructing the standard streams
> out from <iostream> and into the compiled library on targets that support
> the init_priority attribute.  This means that <iostream> no longer
> introduces a separate global constructor in each TU that includes it.
>
> We can do this only if the init_priority attribute is supported because
> we need to force that the stream initialization runs first before any
> user-defined global initializer in programs that that use a static
> libstdc++.a.

I think this breaks initialization of iostreams of shared objects that
are preloaded with LD_PRELOAD.  With the constructor, they initialize
iostreams once they are loaded via their own ELF constructors (even
before libstdc++'s ELF constructors run).  Without the constructor in
<iostream>, that no longer happens.

Thanks,
Florian


  parent reply	other threads:[~2022-11-04 16:57 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-11-04 15:05 [PATCH 1/2] c++: correct __has_attribute(init_priority) Patrick Palka
2022-11-04 15:05 ` [PATCH 2/2] libstdc++: Move stream initialization into compiled library [PR44952] Patrick Palka
2022-11-04 15:24   ` Jonathan Wakely
2022-11-04 16:31     ` Patrick Palka
2022-11-04 16:42       ` Jonathan Wakely
2022-11-04 16:57   ` Florian Weimer [this message]
2022-11-04 17:47     ` Patrick Palka
2022-11-04 18:16       ` Florian Weimer
2022-11-15 16:10   ` Hans-Peter Nilsson
2022-11-04 15:55 ` [PATCH 1/2] c++: correct __has_attribute(init_priority) Jason Merrill

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=87eduizmhj.fsf@oldenburg.str.redhat.com \
    --to=fweimer@redhat.com \
    --cc=gcc-patches@gcc.gnu.org \
    --cc=libstdc++@gcc.gnu.org \
    --cc=ppalka@redhat.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).