From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 6096 invoked by alias); 16 Jul 2003 23:21:13 -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 6089 invoked from network); 16 Jul 2003 23:21:13 -0000 Received: from unknown (HELO localhost.redhat.com) (66.30.197.194) by sources.redhat.com with SMTP; 16 Jul 2003 23:21:13 -0000 Received: from redhat.com (localhost [127.0.0.1]) by localhost.redhat.com (Postfix) with ESMTP id 0D2732B7F for ; Wed, 16 Jul 2003 19:21:40 -0400 (EDT) Message-ID: <3F15DE03.9000104@redhat.com> Date: Wed, 16 Jul 2003 23:21:00 -0000 From: Andrew Cagney User-Agent: Mozilla/5.0 (X11; U; NetBSD macppc; en-US; rv:1.0.2) Gecko/20030223 X-Accept-Language: en-us, en MIME-Version: 1.0 To: gdb-patches@sources.redhat.com Subject: [rfa:dwarf2] Use frame_unwind_address_in_block Content-Type: multipart/mixed; boundary="------------030803000106070003060306" X-SW-Source: 2003-07/txt/msg00324.txt.bz2 This is a multi-part message in MIME format. --------------030803000106070003060306 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Content-length: 378 Hello, This, finally, is the tweak to the dwarf2-unwind code, to use the frame's address-in-block, instead of the frame's PC to select the CFI info. Two test cases stop failing: 1gdb.base/corefile.exp: backtrace in corefile.exp FAIL PASS 2gdb.base/gdb1250.exp: backtrace from abort KFAIL PASS Ok for the mainline? Ok to pull something equivalent into 6.0 branch? Andrew --------------030803000106070003060306 Content-Type: text/plain; name="diffs" Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="diffs" Content-length: 2565 2003-07-16 Andrew Cagney * dwarf2-frame.c (dwarf2_frame_sniffer): Use frame_unwind_address_in_block, instead of frame_pc_unwind. (dwarf2_frame_cache): Ditto. Index: dwarf2-frame.c =================================================================== RCS file: /cvs/src/src/gdb/dwarf2-frame.c,v retrieving revision 1.9 diff -u -r1.9 dwarf2-frame.c --- dwarf2-frame.c 16 Jul 2003 22:29:13 -0000 1.9 +++ dwarf2-frame.c 16 Jul 2003 23:13:29 -0000 @@ -491,15 +491,12 @@ done for "normal" frames and not for resume-type frames (signal handlers, sentinel frames, dummy frames). - We don't do what GCC's does here (yet). It's not clear how - reliable the method is. There's also a problem with finding the - right FDE; see the comment in dwarf_frame_p. If dwarf_frame_p - selected this frame unwinder because it found the FDE for the - next function, using the adjusted return address might not yield - a FDE at all. The problem isn't specific to DWARF CFI; other - unwinders loose in similar ways. Therefore it's probably - acceptable to leave things slightly broken for now. */ - fs->pc = frame_pc_unwind (next_frame); + frame_unwind_address_in_block does just this. + + It's not clear how reliable the method is though - there is the + potential for the register state pre-call being different to that + on return. */ + fs->pc = frame_unwind_address_in_block (next_frame); /* Find the correct FDE. */ fde = dwarf2_frame_find_fde (&fs->pc); @@ -710,15 +707,11 @@ const struct frame_unwind * dwarf2_frame_sniffer (struct frame_info *next_frame) { - CORE_ADDR pc = frame_pc_unwind (next_frame); - /* The way GDB works, this function can be called with PC just after - the last instruction of the function we're supposed to return the - unwind methods for. In that case we won't find the correct FDE; - instead we find the FDE for the next function, or we won't find - an FDE at all. There is a possible solution (see the comment in - dwarf2_frame_cache), GDB doesn't pass us enough information to - implement it. */ - if (dwarf2_frame_find_fde (&pc)) + /* Grab an address that is guarenteed to reside somewhere within the + function. frame_pc_unwind(), for a no-return next function, can + end up returning something past the end of this function's body. */ + CORE_ADDR block_addr = frame_unwind_address_in_block (next_frame); + if (dwarf2_frame_find_fde (&block_addr)) return &dwarf2_frame_unwind; return NULL; --------------030803000106070003060306--