From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 17506 invoked by alias); 16 Oct 2003 21:06:25 -0000 Mailing-List: contact gdb-patches-help@sources.redhat.com; run by ezmlm Precedence: bulk List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-patches-owner@sources.redhat.com Received: (qmail 17491 invoked from network); 16 Oct 2003 21:06:24 -0000 Received: from unknown (HELO localhost.redhat.com) (207.219.125.105) by sources.redhat.com with SMTP; 16 Oct 2003 21:06:24 -0000 Received: from redhat.com (localhost [127.0.0.1]) by localhost.redhat.com (Postfix) with ESMTP id D83032B89; Thu, 16 Oct 2003 17:06:24 -0400 (EDT) Message-ID: <3F8F0850.7080104@redhat.com> Date: Thu, 16 Oct 2003 21:06:00 -0000 From: Andrew Cagney User-Agent: Mozilla/5.0 (X11; U; NetBSD macppc; en-US; rv:1.0.2) Gecko/20030820 X-Accept-Language: en-us, en MIME-Version: 1.0 To: "J. Johnston" Cc: gdb-patches@sources.redhat.com Subject: Re: RFA: frame id enhancement References: <3F81DB50.6020202@redhat.com> <3F8DB78A.4090409@redhat.com> <3F8DD464.6050201@redhat.com> <3F8EC2B3.5040100@redhat.com> <3F8EEC26.60101@redhat.com> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit X-SW-Source: 2003-10/txt/msg00562.txt.bz2 > >> It's the reverse of infrun.c:2383 where the inferior is falling out of a singnal trampoline, I think the assumptions again hold. >> >> infrun.c:2641: if (!(frame_id_inner (current_frame, step_frame_id))) >> >> "Trust me" there's no value add. While the comment reads: >> /* In the case where we just stepped out of a function into the >> middle of a line of the caller, continue stepping, but >> step_frame_id must be modified to current frame */ >> The test also updates step_frame_id when switching between frameless stackless leaf function. The extra test wouldn't fix that problem. I'll try to remember to add some comments to that code. I've done this. > Ok, that simplifies things. I have included a revised patch that allows for the wild-card scenario. We're going to need more comments so that the next person better understands what is going on: + /* The frame's special address. This shall be constant through out the + lifetime of the frame. This is used for architectures that may have + frames that have the same stack_addr and code_addr but are distinct + due to some other qualification (e.g. the ia64 uses a register + stack which is distinct from the memory stack). */ + CORE_ADDR special_addr; can you expand this definition to to note that the value isn't ordered, and that zero is treated as a wild card (its mentioned further down but I think here, at the definition, is better). For the ia64, is/can the second area be described as a register spill area rather than a stack? If the word "stack" can be avoided, the rationale for "special" being un-ordered is stronger. For: NOTE: Given frameless functions A and B, where A calls B (and hence B is inner-to A). The relationships: !eq(A,B); !eq(B,A); !inner(A,B); !inner(B,A); all hold. This is because, while B is inner to A, B is not strictly inner to A (being frameless, they have the same .base value). */ an update is needed, suggest something like: NOTE: Given stackless functions A and B, where A calls B (and hence B is inner-to A). The relationships: !eq(A,B); !eq(B,A); !inner(A,B); !inner(B,A); all hold. This is because, while B is inner-to A, B is not strictly inner-to A. Being stackless, they have an identical .stack_addr value, and differ only by their unordered .code_addr .special_addr values. Because frame_id_inner is only used as a safety net (e.g., detect a corrupt stack) the lack of strictness is not a problem. Code needing to determine an exact relationship between two frames must instead use frame_id_eq and frame_id_unwind. For instance, in the above, to determine that A stepped-into B, the equation "A.id != B.id && A.id == id_unwind (B)" can be used. and a similar update to: frame_id_inner (struct frame_id l, struct frame_id r) { int inner; if (l.stack_addr == 0 || r.stack_addr == 0) /* Like NaN, any operation involving an invalid ID always fails. */ inner = 0; else /* Only return non-zero when strictly inner than. Note that, per comment in "frame.h", there is some fuzz here. Frameless functions are not strictly inner than (same .stack but different .code). */ inner = INNER_THAN (l.stack_addr, r.stack_addr); I can't think of a word better than "special", so I guess special it is :-) Andrew