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From: Andi Kleen <andi@firstfloor.org>
To: Mark Wielaard <mark@klomp.org>
Cc: linux-kernel@vger.kernel.org,
	Masahiro Yamada <masahiroy@kernel.org>,
	Michal Marek <michal.lkml@markovi.net>,
	linux-kbuild@vger.kernel.org, Ian Rogers <irogers@google.com>,
	linux-toolchains@vger.kernel.org,
	Andi Kleen <andi@firstfloor.org>,
	Nick Desaulniers <ndesaulniers@google.com>,
	Segher Boessenkool <segher@kernel.crashing.org>,
	Florian Weimer <fw@deneb.enyo.de>
Subject: Re: [PATCH] Only add -fno-var-tracking-assignments workaround for old GCC versions.
Date: Wed, 14 Oct 2020 08:17:01 -0700	[thread overview]
Message-ID: <20201014151701.vl3gh5e5teb2hqj7@two.firstfloor.org> (raw)
In-Reply-To: <20201014110132.2680-1-mark@klomp.org>

On Wed, Oct 14, 2020 at 01:01:32PM +0200, Mark Wielaard wrote:
> Some old GCC versions between 4.5.0 and 4.9.1 might miscompile code
> with -fvar-tracking-assingments (which is enabled by default with -g -O2).
> commit 2062afb4f added -fno-var-tracking-assignments unconditionally to
> work around this. But newer versions of GCC no longer have this bug, so
> only add it for versions of GCC before 5.0.

Add

... This allows various tools such as a perf probe or gdb debuggers
or systemtap to resolve variable locations using dwarf locations in 
more code.
> 
> Signed-off-by: Mark Wielaard <mark@klomp.org>
> Acked-by: Ian Rogers <irogers@google.com>
> Cc: linux-toolchains@vger.kernel.org
> Cc: Andi Kleen <andi@firstfloor.org>
> Cc: Nick Desaulniers <ndesaulniers@google.com>
> Cc: Segher Boessenkool <segher@kernel.crashing.org>
> Cc: Florian Weimer <fw@deneb.enyo.de>

Reviewed-by: Andi Kleen <ak@linux.intel.com>

-Andi

  reply	other threads:[~2020-10-14 15:17 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-10-06 13:17 Additional debug info to aid cacheline analysis Peter Zijlstra
2020-10-06 19:00 ` Arnaldo Carvalho de Melo
2020-10-08  5:58 ` Stephane Eranian
2020-10-08  7:02   ` Peter Zijlstra
2020-10-08  9:32     ` Mark Wielaard
2020-10-08 21:23       ` Andi Kleen
2020-10-10 20:58         ` Mark Wielaard
2020-10-10 21:51           ` Mark Wielaard
     [not found]             ` <20201010220712.5352-1-mark@klomp.org>
2020-10-10 22:21               ` [PATCH] Only add -fno-var-tracking-assignments workaround for old GCC versions Ian Rogers
2020-10-12 18:59                 ` Nick Desaulniers
2020-10-12 19:12                   ` Mark Wielaard
2020-10-14 15:31                     ` Sedat Dilek
2020-10-14 11:01                 ` Mark Wielaard
2020-10-14 15:17                   ` Andi Kleen [this message]
2020-10-17 12:01                   ` [PATCH V2] " Mark Wielaard
2020-10-19 19:30                     ` Nick Desaulniers
2020-10-20 15:27                     ` Masahiro Yamada
2020-10-10 22:33             ` [PATCH] " Mark Wielaard
2020-10-11 11:04           ` Additional debug info to aid cacheline analysis Segher Boessenkool
2020-10-11 12:15           ` Florian Weimer
2020-10-11 12:23             ` Mark Wielaard
2020-10-11 12:28               ` Florian Weimer
2020-10-30  5:26       ` Namhyung Kim
2020-10-30  9:16         ` Mark Wielaard
2020-10-30 10:10           ` Peter Zijlstra
2020-11-02  8:27             ` Masami Hiramatsu
2020-11-03  4:22               ` Namhyung Kim

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