public inbox for gcc-bugs@sourceware.org help / color / mirror / Atom feed
From: "muecker at gwdg dot de" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug c/108896] provide "element_count" attribute to give more context to __builtin_dynamic_object_size() and -fsanitize=bounds Date: Wed, 08 Mar 2023 20:20:43 +0000 [thread overview] Message-ID: <bug-108896-4-oqHU9ghC1H@http.gcc.gnu.org/bugzilla/> (raw) In-Reply-To: <bug-108896-4@http.gcc.gnu.org/bugzilla/> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108896 --- Comment #32 from Martin Uecker <muecker at gwdg dot de> --- Am Mittwoch, dem 08.03.2023 um 19:20 +0000 schrieb qinzhao at gcc dot gnu.org: > https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108896 > > --- Comment #30 from qinzhao at gcc dot gnu.org --- > (In reply to Martin Uecker from comment #28) > > > The problems with VLA are in my opinion caused by poor > > implementation (e.g. no stack probing etc) and bad > > code generation (Linus was not happy about this) and > > not because anything is fundamentally bad about them > > from the point of language semantics. > > you mean gcc's implementation? how about other compilers? I mostly mean compilers without stack probing (which GCC has but is not activated by default). Code quality is probably still bad for most compilers. > > > VM = variably modified. In C it is a type which is derived from > > a VLA which is not necessarily itself a VLA, e.g. a pointer to > > a VLA. But a VLA is also a VM type. > > Okay. > > > > > struct foo { > > > int len; > > > char (*buf)[.len]; > > > }; > > > > > > > > > This has less issues because the size of the struct then does not depend > > > on the length. > > but I am still not clear on why "the size of the above struct 'foo' does not > depend on the .len?" in my opinion, it should depend on .len. do I miss > anything here? Here the last element is not a flexible array member but a pointer to an array of size len. The size of the pointer is fixed. Martin >
next prev parent reply other threads:[~2023-03-08 20:20 UTC|newest] Thread overview: 53+ messages / expand[flat|nested] mbox.gz Atom feed top 2023-02-22 21:26 [Bug c/108896] New: " kees at outflux dot net 2023-02-22 21:31 ` [Bug c/108896] " kees at outflux dot net 2023-02-22 21:32 ` pinskia at gcc dot gnu.org 2023-02-23 8:44 ` rguenth at gcc dot gnu.org 2023-02-23 9:10 ` jakub at gcc dot gnu.org 2023-02-24 15:44 ` muecker at gwdg dot de 2023-03-01 22:54 ` qinzhao at gcc dot gnu.org 2023-03-01 23:27 ` kees at outflux dot net 2023-03-02 15:50 ` muecker at gwdg dot de 2023-03-02 17:34 ` qinzhao at gcc dot gnu.org 2023-03-02 18:17 ` muecker at gwdg dot de 2023-03-02 18:34 ` muecker at gwdg dot de 2023-03-02 19:47 ` qinzhao at gcc dot gnu.org 2023-03-02 19:56 ` qinzhao at gcc dot gnu.org 2023-03-02 20:07 ` muecker at gwdg dot de 2023-03-03 20:27 ` isanbard at gmail dot com 2023-03-03 21:32 ` muecker at gwdg dot de 2023-03-03 23:18 ` isanbard at gmail dot com 2023-03-04 7:52 ` muecker at gwdg dot de 2023-03-06 19:15 ` isanbard at gmail dot com 2023-03-06 19:18 ` jakub at gcc dot gnu.org 2023-03-06 19:38 ` muecker at gwdg dot de 2023-03-06 19:57 ` muecker at gwdg dot de 2023-03-06 20:05 ` siddhesh at gcc dot gnu.org 2023-03-08 16:56 ` qinzhao at gcc dot gnu.org 2023-03-08 17:13 ` qinzhao at gcc dot gnu.org 2023-03-08 17:36 ` qinzhao at gcc dot gnu.org 2023-03-08 17:38 ` qinzhao at gcc dot gnu.org 2023-03-08 17:43 ` qinzhao at gcc dot gnu.org 2023-03-08 17:48 ` muecker at gwdg dot de 2023-03-08 18:37 ` muecker at gwdg dot de 2023-03-08 19:20 ` qinzhao at gcc dot gnu.org 2023-03-08 19:47 ` qinzhao at gcc dot gnu.org 2023-03-08 20:20 ` muecker at gwdg dot de [this message] 2023-03-08 20:47 ` qinzhao at gcc dot gnu.org 2023-03-29 16:12 ` muecker at gwdg dot de 2023-04-03 20:29 ` qinzhao at gcc dot gnu.org 2023-04-03 21:53 ` muecker at gwdg dot de 2023-04-04 15:07 ` qinzhao at gcc dot gnu.org 2023-04-04 16:33 ` muecker at gwdg dot de 2023-04-04 20:08 ` qinzhao at gcc dot gnu.org 2023-04-19 16:32 ` qinzhao at gcc dot gnu.org 2023-05-03 13:57 ` qinzhao at gcc dot gnu.org 2023-05-03 15:32 ` kees at outflux dot net 2023-05-04 15:16 ` muecker at gwdg dot de 2023-05-04 15:30 ` qinzhao at gcc dot gnu.org 2023-05-25 18:14 ` qinzhao at gcc dot gnu.org 2023-05-25 18:47 ` ndesaulniers at google dot com 2023-10-05 19:54 ` tg at mirbsd dot org 2023-10-05 20:21 ` muecker at gwdg dot de 2023-12-27 6:31 ` sean@rogue-research.com 2024-03-06 14:40 ` qinzhao at gcc dot gnu.org 2024-05-31 17:50 ` qinzhao at gcc dot gnu.org
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=bug-108896-4-oqHU9ghC1H@http.gcc.gnu.org/bugzilla/ \ --to=gcc-bugzilla@gcc.gnu.org \ --cc=gcc-bugs@gcc.gnu.org \ /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: linkBe 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).