From: Segher Boessenkool <segher@kernel.crashing.org>
To: Niklas DAHLQUIST <niklas.dahlquist@st.com>
Cc: Jeff Law <law@redhat.com>,
Torbjorn SVENSSON <torbjorn.svensson@st.com>,
"gcc-patches@gcc.gnu.org" <gcc-patches@gcc.gnu.org>,
"Joey.Ye@arm.com" <Joey.Ye@arm.com>,
Samuel HULTGREN <samuel.hultgren@st.com>,
Christophe LYON <christophe.lyon@st.com>,
Christophe MONAT <christophe.monat@st.com>
Subject: Re: [PATCH] Added information about inline assembler in stack calculations (.su files)
Date: Sat, 08 Dec 2018 12:05:00 -0000 [thread overview]
Message-ID: <20181207233525.GF3803@gate.crashing.org> (raw)
In-Reply-To: <4299eced-a99a-7584-4253-9648dd99e67e@st.com>
Hi!
On Fri, Dec 07, 2018 at 07:51:35AM +0000, Niklas DAHLQUIST wrote:
> On 12/1/18 1:15 AM, Jeff Law wrote:
> > One could argue that allocating stack space inside an ASM is a really
> > bad idea. Consider things like dwarf debugging and unwind tables. If
> > you're allocating stack inside an ASM that stuff is going to be totally
> > wrong.
> >
> > So I think my question before moving forward with something like this is
> > whether or not it makes sense at all to bother dumping data for a
> > scenario that we'd probably suggest developers avoid to begin with.
>
> The purpose of the patch is to notify when the reported stack usage might be
> incorrect. Even if it's bad practice to alter stack in asm, there are
> use cases
> in the embedded world that makes sense. A notable common use case is
> FreeRTOS
> task switch using ARM "naked" attribute and inline asm, which reports "0
> static",
> which gives a faulty stack usage. We have considered the other option to
> report a warning for these cases, but that alternative hasn't appealed
> to us.
Would that work well? Only warn for naked functions? It would work
better for all users that do *not* mess with the stack in their asm ;-)
Segher
next prev parent reply other threads:[~2018-12-08 12:05 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-26 14:03 Torbjorn SVENSSON
2018-11-27 19:03 ` Segher Boessenkool
2018-11-27 19:46 ` Torbjorn SVENSSON
2018-12-07 23:28 ` Segher Boessenkool
2018-12-01 0:16 ` Jeff Law
2018-12-07 7:51 ` Niklas DAHLQUIST
2018-12-08 12:05 ` Segher Boessenkool [this message]
2018-12-14 0:31 ` Jeff Law
2018-12-14 8:58 ` Segher Boessenkool
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