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From: Ammar Faizi <[email protected]>
To: Willy Tarreau <[email protected]>, "Paul E . McKenney" <[email protected]>
Cc: [email protected]
Subject: Re: [PATCH 2/2] tools/nolibc/stdlib: only reference the external environ when inlined
Date: Wed, 23 Mar 2022 20:36:24 +0700	[thread overview]
Message-ID: <[email protected]> (raw)
In-Reply-To: <[email protected]>

On 3/23/22 2:18 PM, Willy Tarreau wrote:
> When building with gcc at -O0 we're seeing link errors due to the
> "environ" variable being referenced by getenv(). The problem is that
> at -O0 gcc will not inline getenv() and will not drop the external
> reference. One solution would be to locally declare the variable as
> weak, but then it would appear in all programs even those not using
> it, and would be confusing to users of getenv() who would forget to
> set environ to envp.
> 
> An alternate approach used in this patch consists in always inlining
> the outer part of getenv() that references this extern so that it's
> always dropped when not used. The biggest part of the function was
> now moved to a new function called _getenv() that's still not inlined
> by default.
> 
> Reported-by: Ammar Faizi <[email protected]>
> Signed-off-by: Willy Tarreau <[email protected]>
> ---

This one works nicely. I will resend my previous RFC after this one
lands in Paul's tree to avoid conflict.

Tested-by: Ammar Faizi <[email protected]>

Thanks!

-- 
Ammar Faizi


  reply	other threads:[~2022-03-23 13:36 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-03-23  7:18 [PATCH 0/2] nolibc: fix two build issues at -O0 Willy Tarreau
2022-03-23  7:18 ` [PATCH 1/2] tools/nolibc/string: do not use __builtin_strlen() " Willy Tarreau
2022-03-23  7:18 ` [PATCH 2/2] tools/nolibc/stdlib: only reference the external environ when inlined Willy Tarreau
2022-03-23 13:36   ` Ammar Faizi [this message]
2022-03-23 23:16 ` [PATCH 0/2] nolibc: fix two build issues at -O0 Paul E. McKenney

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