From: Andreas Schwab <schwab@linux-m68k.org>
To: Jessica Clarke <jrtc27@jrtc27.com>
Cc: Changbin Du <changbin.du@gmail.com>,
Paul Walmsley <paul.walmsley@sifive.com>,
Palmer Dabbelt <palmer@dabbelt.com>,
Albert Ou <aou@eecs.berkeley.edu>,
linux-riscv <linux-riscv@lists.infradead.org>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] riscv: eliminate unreliable __builtin_frame_address(1)
Date: Wed, 19 Jan 2022 22:07:39 +0100 [thread overview]
Message-ID: <87y23b5t9g.fsf@igel.home> (raw)
In-Reply-To: <8F8D535F-3637-4BC7-8853-B709EC5D14C9@jrtc27.com> (Jessica Clarke's message of "Wed, 19 Jan 2022 20:48:48 +0000")
On Jan 19 2022, Jessica Clarke wrote:
> My point is that the only thing that can possibly read the incoming
> frame pointer of a leaf function is the leaf function itself, and since
> it knows where it’s putting it then there is no ABI issue, it just
> remembers where it put it and loads it from there.
llvm sidesteps that issue by always saving ra when creating a frame,
even in a leaf function, so it can use a constant offset.
--
Andreas Schwab, schwab@linux-m68k.org
GPG Key fingerprint = 7578 EB47 D4E5 4D69 2510 2552 DF73 E780 A9DA AEC1
"And now for something completely different."
next prev parent reply other threads:[~2022-01-19 21:07 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-01-17 15:44 [PATCH] riscv: eliminate unreliable __builtin_frame_address(1) Changbin Du
2022-01-17 16:10 ` Andreas Schwab
2022-01-17 17:33 ` Jessica Clarke
2022-01-19 10:58 ` Andreas Schwab
2022-01-19 19:05 ` Jessica Clarke
2022-01-19 20:44 ` Andreas Schwab
2022-01-19 20:48 ` Jessica Clarke
2022-01-19 21:07 ` Andreas Schwab [this message]
2022-01-19 21:27 ` Jessica Clarke
2022-01-19 23:53 ` Andreas Schwab
2022-01-20 0:15 ` Palmer Dabbelt
2022-02-04 21:56 ` Palmer Dabbelt
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