On 4/12/21 2:18 PM, Jakub Jelinek wrote:
> On Mon, Apr 12, 2021 at 02:15:16PM +0200, Martin Liška wrote:
>> The old syntax with the alias is quite ugly..
>
> Not that much. And users have no other option (besides inline asm
> but that doesn't work with LTO well).
>
>>> so that people who don't have gcc configured against
>>> binutils 2.35 or newer know what to do instead.
>>
>> ... and symver support for older binutils releases is fragile due to:
>>
>> Changes in 2.35:
>>
>> * Extend .symver directive to update visibility of the original symbol
>> and assign one original symbol to different versioned symbols.
>
> That is a change that allows the new syntax.
> The old syntax (on the as/ld side) have worked for the last 20+ years
> just fine.
>
> Jakub
>
All right, so something like this?
Thanks,
Martin
>From 750b715225d480fcb74e765623d54acc42ac25e3 Mon Sep 17 00:00:00 2001
From: Martin Liska <mli...@suse.cz>
Date: Mon, 12 Apr 2021 13:42:33 +0200
Subject: [PATCH] docs: update symver attribute description
gcc/ChangeLog:
* doc/extend.texi: Be more precise in documentation
of symver attribute.
---
gcc/doc/extend.texi | 22 +++++++++++++---------
1 file changed, 13 insertions(+), 9 deletions(-)
diff --git a/gcc/doc/extend.texi b/gcc/doc/extend.texi
index e28e1860990..75e4a43a8c5 100644
--- a/gcc/doc/extend.texi
+++ b/gcc/doc/extend.texi
@@ -3848,23 +3848,27 @@ foo_v1 (void)
Will produce a @code{.symver foo_v1, foo@@VERS_1} directive in the assembler
output.
-One can also define multiple version for a given symbol.
+One can also define multiple version for a given symbol
+(starting from binutils 2.35).
@smallexample
__attribute__ ((__symver__ ("foo@@VERS_2"), __symver__ ("foo@@VERS_3")))
int symver_foo_v1 (void)
@{
@}
-
-__attribute__ ((__symver__ ("bar@@VERS_2")))
-__attribute__ ((__symver__ ("bar@@VERS_3")))
-int symver_bar_v1 (void)
-@{
-@}
@end smallexample
-This example creates an alias of @code{foo_v1} with symbol name
-@code{symver_foo_v1} which will be version @code{VERS_2} of @code{foo}.
+This example creates a symbol name @code{symver_foo_v1}
+which will be version @code{VERS_2} and @code{VERS_3} of @code{foo}.
+
+If you have an older release of binutils release, then symbol alias needs to
+be used:
+
+@smallexample
+__attribute__ ((__symver__ ("foo@@VERS_2")))
+__attribute__ ((alias ("foo_v1")))
+int symver_foo_v1 (void);
+@end smallexample
Finally if the parameter is @code{"@var{name2}@@@@@var{nodename}"} then in
addition to creating a symbol version (as if
--
2.31.1
