From: Wilco Dijkstra <Wilco.Dijkstra@arm.com>
To: Szabolcs Nagy <Szabolcs.Nagy@arm.com>,
"maskray@google.com" <maskray@google.com>
Cc: 'GNU C Library' <libc-alpha@sourceware.org>
Subject: [PATCH 2/3] Revert "[AArch64][BZ #17711] Fix extern protected data handling"
Date: Tue, 24 May 2022 13:46:32 +0000 [thread overview]
Message-ID: <DB6PR0801MB187936CC075E089479679EF683D79@DB6PR0801MB1879.eurprd08.prod.outlook.com> (raw)
Hi,
>> * Clang code generation treats STV_PROTECTED the same way as STV_HIDDEN:
>> no GOT-generating relocation in the first place.
We should change GCC's behaviour to match this - is this something that
applies to all targets?
>> * gold and lld reject copy relocation on a STV_PROTECTED symbol.
>> * Nowadays -fpie/-fpic modes are popular. GCC/Clang's codegen uses
>> GOT-generating relocation when accessing an default visibility
>> external symbol which avoids copy relocation.
Would it be reasonable to add a way to override settings for binaries?
For example if all imported symbols are marked with the correct visibility,
PIE binaries could avoid using GOT for default visibility external symbols to
get better performance. And non-PIE binaries could force GOT accesses for
non-default visibility to avoid copy relocations and support protected visibility.
Cheers,
Wilco
next reply other threads:[~2022-05-24 13:46 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-05-24 13:46 Wilco Dijkstra [this message]
2022-05-24 17:28 ` maskray
2022-05-24 21:58 ` H.J. Lu
2022-05-25 17:13 ` Wilco Dijkstra
2022-05-25 18:21 ` Florian Weimer
2022-05-25 20:44 ` H.J. Lu
2022-05-26 19:17 ` Wilco Dijkstra
2022-05-26 19:25 ` Florian Weimer
2022-05-26 20:03 ` Wilco Dijkstra
2022-05-26 21:27 ` H.J. Lu
2022-05-27 12:43 ` Florian Weimer
2022-05-31 2:03 ` H.J. Lu
2022-05-31 7:49 ` Fangrui Song
2022-05-31 9:42 ` Wilco Dijkstra
2022-05-31 13:47 ` H.J. Lu
2022-05-31 7:42 ` Fangrui Song
2022-05-25 20:10 ` maskray
-- strict thread matches above, loose matches on Subject: below --
2022-05-01 6:06 [PATCH 0/3] Simplify ELF_RTYPE_CLASS_EXTERN_PROTECTED_DATA and revert aarch64/arm's extern protected data handling Fangrui Song
2022-05-01 6:06 ` [PATCH 2/3] Revert "[AArch64][BZ #17711] Fix extern protected data handling" Fangrui Song
2022-05-23 20:10 ` Szabolcs Nagy
2022-05-23 20:17 ` Fangrui Song
2022-05-24 5:13 ` Fangrui Song
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