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From: Fangrui Song <i@maskray.me>
To: "H.J. Lu" <hjl.tools@gmail.com>
Cc: binutils@sourceware.org
Subject: Re: [PATCH] x86: Keep __patchable_function_entries sections with --gc-sections
Date: Sat, 01 Feb 2020 17:34:00 -0000	[thread overview]
Message-ID: <20200201173429.ep5siwkbhz5osehk@google.com> (raw)
In-Reply-To: <20200201162613.2023476-1-hjl.tools@gmail.com>

On 2020-02-01, H.J. Lu wrote:
>After all text sections have been garbage collected, if a
>__patchable_function_entries section references a section which
>wasn't marked, mark it with SEC_EXCLUDE and return NULL.  Otherwise,
>keep it.
>
>Should it be handled in _bfd_elf_gc_mark_extra_sections?

Thanks for paying attention to these feature requests.

I referenced GNU as and ld requests at
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93492#c2
If we

* implement SHF_LINK_ORDER
* allow multiple sections with the same name ("unique")
* teach GCC to use SHF_LINK_ORDER and "unique" (see https://gcc.gnu.org/ml/gcc/2020-01/msg00067.html)

An ad-hoc gc marking will be unnecessary.

SHF_LINK_ORDER has been used in a few sanitizers. Now we know
__patchable_function_entries can benefit from it.  In the future, they
may be instances. We really need a general solution.

  parent reply	other threads:[~2020-02-01 17:34 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-02-01 16:26 H.J. Lu
2020-02-01 17:19 ` H.J. Lu
2020-02-01 17:34 ` Fangrui Song [this message]
2020-02-01 17:43   ` H.J. Lu
2020-02-01 18:21     ` Fangrui Song
2020-02-02 23:44       ` [PATCH] Issue an error for GC on __patchable_function_entries section H.J. Lu
2020-02-03  0:57         ` Fangrui Song
2020-02-03  1:18           ` H.J. Lu
2020-02-07  2:23             ` [PATCH] ld: " H.J. Lu
2020-02-07  3:28               ` Alan Modra

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