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From: "jakub at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug c++/102295] ELF symbol sizes for variable-length objects are too small (C++)
Date: Mon, 13 Sep 2021 16:38:43 +0000	[thread overview]
Message-ID: <bug-102295-4-CJs4pdcryb@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-102295-4@http.gcc.gnu.org/bugzilla/>

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102295

--- Comment #3 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Note, we have other issues, consider:
struct A
{
  float a;
  int b[];
};

int x[4];
struct A c = { 42.0f, { ++x[0], ++x[1], ++x[2], ++x[3] } };
When splitting the init into DECL_INITIAL constant initializer and runtime
initialization, the flexible array member initialization is moved completely
into runtime initialization and nothing remains in DECL_INITIAL from it.  For
initializers of fields other than flexible array members that is ok, but by
getting rid of the flex array member initializer the size emitted for the var
in assembly doesn't include the flexible array member at all.  That is worse
than having too small .size, in this case it means overwriting whatever is
after the variable.  Small .size actually isn't wrong-code...

  parent reply	other threads:[~2021-09-13 16:38 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-12 22:46 [Bug c++/102295] New: " pinskia at gcc dot gnu.org
2021-09-12 23:15 ` [Bug c++/102295] " pinskia at gcc dot gnu.org
2021-09-13 16:34 ` jakub at gcc dot gnu.org
2021-09-13 16:38 ` jakub at gcc dot gnu.org [this message]
2021-09-13 20:40 ` pinskia at gcc dot gnu.org
2021-09-14 14:57 ` cvs-commit at gcc dot gnu.org
2021-09-14 14:59 ` jakub at gcc dot gnu.org
2021-09-15 20:22 ` cvs-commit at gcc dot gnu.org
2021-09-15 23:05 ` cvs-commit at gcc dot gnu.org
2021-09-15 23:05 ` cvs-commit at gcc dot gnu.org
2021-09-16  8:50 ` jakub at gcc dot gnu.org
2022-05-10  8:20 ` cvs-commit at gcc dot gnu.org
2022-05-10  8:20 ` cvs-commit at gcc dot gnu.org
2022-05-11  6:22 ` cvs-commit at gcc dot gnu.org
2022-05-11  6:22 ` cvs-commit at gcc dot gnu.org
2022-05-11  6:36 ` jakub at gcc dot gnu.org

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