From mboxrd@z Thu Jan 1 00:00:00 1970 From: Kevin B. Hendricks To: Franz Sirl , Geoff Keating Cc: khendricks@ivey.uwo.ca, gcc@gcc.gnu.org, dje@watson.ibm.com Subject: Re: g++ Bug? use of alloca in a function prevents exception handler walkback on ppc linux Date: Mon, 18 Dec 2000 06:30:00 -0000 Message-id: <00121809304701.00856@localhost> References: <00121423310900.02039@enzo.bigblue.local> <4.3.2.7.2.20001218143529.026ccdc0@mail.lauterbach.com> X-SW-Source: 2000-12/msg00562.html Hi Franz, > The code is nearly the same (I compared the assembly), I believe this was a > temporary failure and not related to the bug you are referring to. What > makes me wonder though is the code generated for "thrower" in Kevin's > testcase, that looks bogus. It seems to me that the code is using an > uninitialized and unallocated stackslot for aExc, which overlays (!) with > the register save area, r31 in this example. The bug is already in the > initial RTL dump, which would suggest that except.c and cp/except.c have a > bug here. > > > > Anyway, Kevin is working with gcc-2.95.3 so I'll look into backporting > > your > > > fix, cause I don't have time to do gcc-2.97 RPM's before xmas. > > > >Sure. As a workaround, this is suitable for 2.95.3. > > As this bug turned out to be a different one than you thought (?), the > solution for gcc-2.95.3 is really simple and related to the unofficial > DWARF EH patch used on Linux/PPC. It turns out the patch missed to call > dwarf2out_def_cfa() after the framepointer activating "mr 31,1". Fixing > this lets the testcase succeed. > > Kevin, I'll upload new RPM's as soon as the build finished. Great, I have a much more complex testcase (the actual bridges code in openoffice) which actually works if I change from alloca to malloc based versions. I will convert it back to alloca and test the new compiler. Thanks! Kevin --- Kevin B. Hendricks, Associate Professor Operations and Information Technology Richard Ivey School of Business, UWO, London ON, CANADA (519) 661-3874