From mboxrd@z Thu Jan 1 00:00:00 1970 From: Cary Coutant Date: Mon, 26 Mar 2001 22:58:42 +0000 Subject: Re: [Linux-ia64] Unwind problem for __attribute__ noreturn Message-Id: List-Id: References: In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linux-ia64@vger.kernel.org >Just to make it explicit. Will the runtime architecture be updated to >forbid a call as the last instruction in an unwind region? Or do we >have to somehow cope with this corner case? I have made the following proposal, in the IA-64 psABI group, to amend the runtime document: >... I propose adding the following rule to Section 8.7, >"Requirements for unwinding the stack," in the Software Conventions and >Runtime Architecture document: > >* The return BR must contain an address that can be used to > determine the unwind state of the calling procedure. For > example, a compiler may choose to optimize calls to > procedures that do not return. If it does so, however, it must > ensure that the unwind information for the procedure properly > describes the unwind state at the return point, even though the > return point will never be executed. This may require the > insertion of an otherwise unnecessary nop or break instruction. -cary