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Fri, 29 Jan 2021 07:19:54 -0800 (PST) Received: from zen.linaroharston ([51.148.130.216]) by smtp.gmail.com with ESMTPSA id f18sm9973264wmj.28.2021.01.29.07.19.53 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 29 Jan 2021 07:19:53 -0800 (PST) Received: from zen (localhost [127.0.0.1]) by zen.linaroharston (Postfix) with ESMTP id E87721FF7E; Fri, 29 Jan 2021 15:19:52 +0000 (GMT) References: <20210129130330.30820-1-peter.maydell@linaro.org> User-agent: mu4e 1.5.7; emacs 28.0.50 From: Alex =?utf-8?Q?Benn=C3=A9e?= To: Peter Maydell Subject: Re: [PATCH] accel/tcg: Add URL of clang bug to comment about our workaround Date: Fri, 29 Jan 2021 15:19:46 +0000 In-reply-to: <20210129130330.30820-1-peter.maydell@linaro.org> Message-ID: <87y2gbsrc7.fsf@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Received-SPF: pass client-ip=2a00:1450:4864:20::329; envelope-from=alex.bennee@linaro.org; helo=mail-wm1-x329.google.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Paolo Bonzini , Richard Henderson , qemu-devel@nongnu.org Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Peter Maydell writes: > In cpu_exec() we have a longstanding workaround for compilers which > do not correctly implement the part of the sigsetjmp()/siglongjmp() > spec which requires that local variables which are not changed > between the setjmp and the longjmp retain their value. > > I recently ran across the upstream clang bug report for this; add a > link to it to the comment describing the workaround, and generally > expand the comment, so that we have a reasonable chance in future of > understanding why it's there and determining when we can remove it, > assuming clang eventually fixes the bug. > > Remove the /* buggy compiler */ comments on the #else and #endif: > they don't add anything to understanding and are somewhat misleading > since they're sandwiching the code path for *non*-buggy compilers. > > Signed-off-by: Peter Maydell Reviewed-by: Alex Benn=C3=A9e --=20 Alex Benn=C3=A9e