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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 11:58:04 +0100	[thread overview]
Message-ID: <87v8yg6lhf.fsf@igel.home> (raw)
In-Reply-To: <C2470F2D-9E45-49D7-A03B-E6A7BB4B9738@jrtc27.com> (Jessica Clarke's message of "Mon, 17 Jan 2022 17:33:40 +0000")

On Jan 17 2022, Jessica Clarke wrote:

> Yes, this is a bug, that is always wrong. LLVM gets this right.

Is that an ABI requirement?  In case of a leaf function, gcc saves the
caller's frame pointer in the first slot, not the second (it doesn't
save the return address).

-- 
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."

_______________________________________________
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WARNING: multiple messages have this Message-ID (diff)
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 11:58:04 +0100	[thread overview]
Message-ID: <87v8yg6lhf.fsf@igel.home> (raw)
In-Reply-To: <C2470F2D-9E45-49D7-A03B-E6A7BB4B9738@jrtc27.com> (Jessica Clarke's message of "Mon, 17 Jan 2022 17:33:40 +0000")

On Jan 17 2022, Jessica Clarke wrote:

> Yes, this is a bug, that is always wrong. LLVM gets this right.

Is that an ABI requirement?  In case of a leaf function, gcc saves the
caller's frame pointer in the first slot, not the second (it doesn't
save the return address).

-- 
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."

  reply	other threads:[~2022-01-19 10:58 UTC|newest]

Thread overview: 24+ 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 15:44 ` Changbin Du
2022-01-17 16:10 ` Andreas Schwab
2022-01-17 16:10   ` Andreas Schwab
2022-01-17 17:33 ` Jessica Clarke
2022-01-17 17:33   ` Jessica Clarke
2022-01-19 10:58   ` Andreas Schwab [this message]
2022-01-19 10:58     ` Andreas Schwab
2022-01-19 19:05     ` Jessica Clarke
2022-01-19 19:05       ` Jessica Clarke
2022-01-19 20:44       ` Andreas Schwab
2022-01-19 20:44         ` Andreas Schwab
2022-01-19 20:48         ` Jessica Clarke
2022-01-19 20:48           ` Jessica Clarke
2022-01-19 21:07           ` Andreas Schwab
2022-01-19 21:07             ` Andreas Schwab
2022-01-19 21:27             ` Jessica Clarke
2022-01-19 21:27               ` Jessica Clarke
2022-01-19 23:53               ` Andreas Schwab
2022-01-19 23:53                 ` Andreas Schwab
2022-01-20  0:15                 ` Palmer Dabbelt
2022-01-20  0:15                   ` Palmer Dabbelt
2022-02-04 21:56 ` Palmer Dabbelt
2022-02-04 21:56   ` Palmer Dabbelt

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