From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 27553 invoked by alias); 4 Jan 2003 17:13:06 -0000 Mailing-List: contact gdb-help@sources.redhat.com; run by ezmlm Precedence: bulk List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-owner@sources.redhat.com Received: (qmail 27546 invoked from network); 4 Jan 2003 17:13:05 -0000 Received: from unknown (HELO duracef.shout.net) (204.253.184.12) by 209.249.29.67 with SMTP; 4 Jan 2003 17:13:05 -0000 Received: (from mec@localhost) by duracef.shout.net (8.11.6/8.11.6) id h04HCrw01931; Sat, 4 Jan 2003 11:12:53 -0600 Date: Sat, 04 Jan 2003 17:13:00 -0000 From: Michael Elizabeth Chastain Message-Id: <200301041712.h04HCrw01931@duracef.shout.net> To: gdb@sources.redhat.com, jimb@redhat.com Subject: Replace TYPE_FLAG_PROTOTYPED with two flags X-SW-Source: 2003-01/txt/msg00042.txt.bz2 I've got these FAILs with gcc -gdwarf-2, both v2 and v3: FAIL: gdb.base/callfuncs.exp: p t_float_values(3.14159,-2.3765) FAIL: gdb.base/callfuncs.exp: p t_float_values(float_val1,float_val2) FAIL: gdb.base/callfuncs.exp: p t_float_values(3.14159,float_val2) FAIL: gdb.base/callfuncs.exp: p t_float_values(float_val1,-2.3765) This happens because t_float_values has no prototype. The dwarf2 reader leaves TYPE_FLAG_PROTOTYPED clear, but later on, value_arg_coerce refuses to trust the flag and guesses. Indeed, Jim Blandy has been down this path recently: http://sources.redhat.com/ml/gdb-patches/2001-11/threads.html#00529 I am writing a new patch ("six weeks in the laboratory can often save fifteen minutes in the library"). Instead of TYPE_FLAG_PROTOTYPED and TYPE_FLAG_MAYBE_PROTOTYPED, I use a more solid model: TYPE_FLAG_PROTO_KNOWN gdb knows whether there is a prototype TYPE_FLAG_PROTO_YES if proto_known is true, says whether there is a prototype The dwarf and dwarf-2 readers always set TYPE_FLAG_PROTO_KNOWN, and may set TYPE_FLAG_PROTO_YES. The stabs reader sets TYPE_FLAG_PROTO_KNOWN when it finds an actual prototype (an argument list in the stabs). This does not happen with gcc, but the comments say that it can happen with sun cc. My big question here is: is it safe to assume that dwarf and dwarf-2 have accurate prototype information? That is, if there is no prototype in the debug information, can gdb really be sure that the function has no prototype and then rely on that information? My testing says that it can, for dwarf-2. I haven't tested dwarf yet. (dwarf might hit the OBSOLETE list some day but it's not OBSOLETE yet). The stabs+ case still works because TYPE_FLAG_PROTO_KNOWN==0 behaves like the existing code. If it's safe to make this assumption, then I would like to proceed with my patch, because this fixes a real bug with dwarf-2. My goal here is to fix bugs where dwarf-2 behaves worse than stabs+. Michael C