From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 678 invoked by alias); 30 Oct 2002 23:41:13 -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 619 invoked from network); 30 Oct 2002 23:41:12 -0000 Received: from unknown (HELO crack.them.org) (65.125.64.184) by sources.redhat.com with SMTP; 30 Oct 2002 23:41:12 -0000 Received: from nevyn.them.org ([66.93.61.169] ident=mail) by crack.them.org with asmtp (Exim 3.12 #1 (Debian)) id 1873O5-0000Hd-00 for ; Wed, 30 Oct 2002 18:40:41 -0600 Received: from drow by nevyn.them.org with local (Exim 3.36 #1 (Debian)) id 1872T6-000627-00 for ; Wed, 30 Oct 2002 18:41:48 -0500 Date: Wed, 30 Oct 2002 15:41:00 -0000 From: Daniel Jacobowitz To: gdb-patches@sources.redhat.com Subject: Re: RFA/types: Clean up use of field bitsize Message-ID: <20021030234148.GA22769@nevyn.them.org> Mail-Followup-To: gdb-patches@sources.redhat.com References: <20020930010515.GA27762@nevyn.them.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20020930010515.GA27762@nevyn.them.org> User-Agent: Mutt/1.5.1i X-SW-Source: 2002-10/txt/msg00596.txt.bz2 Does anyone have a comment on this patch? If not, I'll commit it in a couple of days, after I'm added to the global write list. (The type code has no specific maintainer, the debug reader and language parts I consider obvious, and the patch is over a month old now.) On Sun, Sep 29, 2002 at 09:05:15PM -0400, Daniel Jacobowitz wrote: > Right now, we have this really disturbing comment: > > /* Size of this field, in bits, or zero if not packed. > For an unpacked field, the field's type's length > says how many bytes the field occupies. > A value of -1 or -2 indicates a static field; -1 means the location > is specified by the label loc.physname; -2 means that loc.physaddr > specifies the actual address. */ > > Think about this for a moment. While in practice a static member is never > going to be packed, and in at least C++ can not be a bit-field, that's not > logically obvious for other languages. I don't know Ada but I wouldn't be > surprised if there were some construct which violated this assumption. > > Worse, all sorts of places don't check for negative bitsize at all. It may > be that they're all safe - I didn't spend a lot of time working out problem > cases - but I have my doubts. > > So, since I needed to gain a new field here anyway, and since I have no > compunctions about shrinking this field a little (packed bitfields of size > greater than a couple of words are allowed in some languages IIRC (including > GNU C maybe? Although they are not allowed in ISO C99), but they're > definitely dodgy), and since signed bitfields are not portable, I cleaned up > the construct. It turned out to be painless except for making sure symbol > readers initialized it, which was a little tedious. > > This patch: > Moves 'artificial' out from 'loc' and makes it a bitfield > Creates a 'static_kind' bitfield > Makes 'bitsize' into a bitfield > > The goal is to allow more kinds of fields to be marked artificial - > particularly data members. After this patch I'll submit the followup to > mark DW_AT_artificial members as artificial types. > > OK? > > -- > Daniel Jacobowitz > MontaVista Software Debian GNU/Linux Developer > > 2002-09-29 Daniel Jacobowitz > > * gdbtypes.h (struct main_type): Move artificial flag out of > loc. New member of ``struct field'' named static_kind. Reduce > overloaded meaning of bitsize. > (FIELD_ARTIFICIAL, SET_FIELD_PHYSNAME, SET_FIELD_PHYSADDR) > (TYPE_FIELD_STATIC, TYPE_FIELD_STATIC_HAS_ADDR): Likewise. > (FIELD_STATIC_KIND, TYPE_FIELD_STATIC_KIND): New macros. > > * ada-lang.c (fill_in_ada_prototype): Initialize static_kind for > new fields. > (template_to_fixed_record_type, template_to_static_fixed_type) > (to_record_with_fixed_variant_part): Likewise. > * coffread.c (coff_read_struct_type, coff_read_enum_type): Likewise. > * dwarf2read.c (dwarf2_add_field, read_enumeration): Likewise. > * dwarfread.c (struct_type, enum_type): Likewise. > * hpread.c (hpread_read_enum_type) > (hpread_read_function_type, hpread_read_doc_function_type) > (hpread_read_struct_type): Likewise. > * mdebugread.c (parse_symbol): Likewise. > > Index: ada-lang.c > =================================================================== > RCS file: /cvs/src/src/gdb/ada-lang.c,v > retrieving revision 1.9 > diff -u -p -r1.9 ada-lang.c > --- ada-lang.c 8 Sep 2002 17:43:26 -0000 1.9 > +++ ada-lang.c 30 Sep 2002 00:43:30 -0000 > @@ -4189,6 +4189,7 @@ fill_in_ada_prototype (struct symbol *fu > case LOC_REGPARM_ADDR: > TYPE_FIELD_BITPOS (ftype, nargs) = nargs; > TYPE_FIELD_BITSIZE (ftype, nargs) = 0; > + TYPE_FIELD_STATIC_KIND (ftype, nargs) = 0; > TYPE_FIELD_TYPE (ftype, nargs) = > lookup_pointer_type (check_typedef (SYMBOL_TYPE (sym))); > TYPE_FIELD_NAME (ftype, nargs) = SYMBOL_NAME (sym); > @@ -4202,6 +4203,7 @@ fill_in_ada_prototype (struct symbol *fu > case LOC_BASEREG_ARG: > TYPE_FIELD_BITPOS (ftype, nargs) = nargs; > TYPE_FIELD_BITSIZE (ftype, nargs) = 0; > + TYPE_FIELD_STATIC_KIND (ftype, nargs) = 0; > TYPE_FIELD_TYPE (ftype, nargs) = check_typedef (SYMBOL_TYPE (sym)); > TYPE_FIELD_NAME (ftype, nargs) = SYMBOL_NAME (sym); > nargs += 1; > @@ -6046,6 +6048,7 @@ template_to_fixed_record_type (struct ty > * rediscover why we needed field_offset and fix it properly. */ > TYPE_FIELD_BITPOS (rtype, f) = off; > TYPE_FIELD_BITSIZE (rtype, f) = 0; > + TYPE_FIELD_STATIC_KIND (rtype, f) = 0; > > if (ada_is_variant_part (type, f)) > { > @@ -6149,6 +6152,7 @@ template_to_static_fixed_type (struct ty > { > TYPE_FIELD_BITPOS (type, f) = 0; > TYPE_FIELD_BITSIZE (type, f) = 0; > + TYPE_FIELD_STATIC_KIND (type, f) = 0; > > if (is_dynamic_field (templ_type, f)) > { > @@ -6218,6 +6222,7 @@ to_record_with_fixed_variant_part (struc > TYPE_FIELD_TYPE (rtype, nfields - 1) = branch_type; > TYPE_FIELD_NAME (rtype, nfields - 1) = "S"; > TYPE_FIELD_BITSIZE (rtype, nfields - 1) = 0; > + TYPE_FIELD_STATIC_KIND (rtype, nfields - 1) = 0; > TYPE_LENGTH (rtype) += TYPE_LENGTH (branch_type); > -TYPE_LENGTH (TYPE_FIELD_TYPE (type, nfields - 1)); > } > Index: coffread.c > =================================================================== > RCS file: /cvs/src/src/gdb/coffread.c,v > retrieving revision 1.29 > diff -u -p -r1.29 coffread.c > --- coffread.c 22 Aug 2002 05:50:11 -0000 1.29 > +++ coffread.c 30 Sep 2002 00:43:30 -0000 > @@ -1997,6 +1997,7 @@ coff_read_struct_type (int index, int le > FIELD_TYPE (list->field) = decode_type (ms, ms->c_type, &sub_aux); > FIELD_BITPOS (list->field) = 8 * ms->c_value; > FIELD_BITSIZE (list->field) = 0; > + FIELD_STATIC_KIND (list->field) = 0; > nfields++; > break; > > @@ -2015,6 +2016,7 @@ coff_read_struct_type (int index, int le > FIELD_TYPE (list->field) = decode_type (ms, ms->c_type, &sub_aux); > FIELD_BITPOS (list->field) = ms->c_value; > FIELD_BITSIZE (list->field) = sub_aux.x_sym.x_misc.x_lnsz.x_size; > + FIELD_STATIC_KIND (list->field) = 0; > nfields++; > break; > > @@ -2135,6 +2137,7 @@ coff_read_enum_type (int index, int leng > if (SYMBOL_VALUE (xsym) < 0) > unsigned_enum = 0; > TYPE_FIELD_BITSIZE (type, n) = 0; > + TYPE_FIELD_STATIC_KIND (type, n) = 0; > } > if (syms == osyms) > break; > Index: dwarf2read.c > =================================================================== > RCS file: /cvs/src/src/gdb/dwarf2read.c,v > retrieving revision 1.66 > diff -u -p -r1.66 dwarf2read.c > --- dwarf2read.c 3 Sep 2002 17:32:11 -0000 1.66 > +++ dwarf2read.c 30 Sep 2002 00:43:33 -0000 > @@ -2055,6 +2055,8 @@ dwarf2_add_field (struct field_info *fip > /* Get type of field. */ > fp->type = die_type (die, objfile, cu_header); > > + FIELD_STATIC_KIND (*fp) = 0; > + > /* Get bit size of field (zero if none). */ > attr = dwarf_attr (die, DW_AT_bit_size); > if (attr) > @@ -2163,6 +2165,7 @@ dwarf2_add_field (struct field_info *fip > FIELD_BITPOS (*fp) = (decode_locdesc (DW_BLOCK (attr), objfile, cu_header) > * bits_per_byte); > FIELD_BITSIZE (*fp) = 0; > + FIELD_STATIC_KIND (*fp) = 0; > FIELD_TYPE (*fp) = die_type (die, objfile, cu_header); > FIELD_NAME (*fp) = type_name_no_tag (fp->type); > fip->nbaseclasses++; > @@ -2667,6 +2670,7 @@ read_enumeration (struct die_info *die, > FIELD_TYPE (fields[num_fields]) = NULL; > FIELD_BITPOS (fields[num_fields]) = SYMBOL_VALUE (sym); > FIELD_BITSIZE (fields[num_fields]) = 0; > + FIELD_STATIC_KIND (fields[num_fields]) = 0; > > num_fields++; > } > Index: dwarfread.c > =================================================================== > RCS file: /cvs/src/src/gdb/dwarfread.c,v > retrieving revision 1.14 > diff -u -p -r1.14 dwarfread.c > --- dwarfread.c 1 Aug 2002 17:18:32 -0000 1.14 > +++ dwarfread.c 30 Sep 2002 00:43:33 -0000 > @@ -1027,6 +1027,7 @@ struct_type (struct dieinfo *dip, char * > &objfile->type_obstack); > FIELD_TYPE (list->field) = decode_die_type (&mbr); > FIELD_BITPOS (list->field) = 8 * locval (&mbr); > + FIELD_STATIC_KIND (list->field) = 0; > /* Handle bit fields. */ > FIELD_BITSIZE (list->field) = mbr.at_bit_size; > if (BITS_BIG_ENDIAN) > @@ -1694,6 +1695,7 @@ enum_type (struct dieinfo *dip, struct o > list = new; > FIELD_TYPE (list->field) = NULL; > FIELD_BITSIZE (list->field) = 0; > + FIELD_STATIC_KIND (list->field) = 0; > FIELD_BITPOS (list->field) = > target_to_host (scan, TARGET_FT_LONG_SIZE (objfile), GET_SIGNED, > objfile); > Index: gdbtypes.h > =================================================================== > RCS file: /cvs/src/src/gdb/gdbtypes.h,v > retrieving revision 1.36 > diff -u -p -r1.36 gdbtypes.h > --- gdbtypes.h 14 Sep 2002 02:09:39 -0000 1.36 > +++ gdbtypes.h 30 Sep 2002 00:43:34 -0000 > @@ -381,22 +381,25 @@ struct main_type > > CORE_ADDR physaddr; > char *physname; > - > - /* For a function or member type, this is 1 if the argument is marked > - artificial. Artificial arguments should not be shown to the > - user. */ > - int artificial; > } > loc; > > + /* For a function or member type, this is 1 if the argument is marked > + artificial. Artificial arguments should not be shown to the > + user. */ > + unsigned int artificial : 1; > + > + /* This flag is zero for non-static fields, 1 for fields whose location > + is specified by the label loc.physname, and 2 for fields whose location > + is specified by loc.physaddr. */ > + > + unsigned int static_kind : 2; > + > /* Size of this field, in bits, or zero if not packed. > For an unpacked field, the field's type's length > - says how many bytes the field occupies. > - A value of -1 or -2 indicates a static field; -1 means the location > - is specified by the label loc.physname; -2 means that loc.physaddr > - specifies the actual address. */ > + says how many bytes the field occupies. */ > > - int bitsize; > + unsigned int bitsize : 29; > > /* In a struct or union type, type of this field. > In a function or member type, type of this argument. > @@ -793,14 +796,15 @@ extern void allocate_cplus_struct_type ( > #define FIELD_TYPE(thisfld) ((thisfld).type) > #define FIELD_NAME(thisfld) ((thisfld).name) > #define FIELD_BITPOS(thisfld) ((thisfld).loc.bitpos) > -#define FIELD_ARTIFICIAL(thisfld) ((thisfld).loc.artificial) > +#define FIELD_ARTIFICIAL(thisfld) ((thisfld).artificial) > #define FIELD_BITSIZE(thisfld) ((thisfld).bitsize) > +#define FIELD_STATIC_KIND(thisfld) ((thisfld).static_kind) > #define FIELD_PHYSNAME(thisfld) ((thisfld).loc.physname) > #define FIELD_PHYSADDR(thisfld) ((thisfld).loc.physaddr) > #define SET_FIELD_PHYSNAME(thisfld, name) \ > - ((thisfld).bitsize = -1, FIELD_PHYSNAME(thisfld) = (name)) > + ((thisfld).static_kind = 1, FIELD_PHYSNAME(thisfld) = (name)) > #define SET_FIELD_PHYSADDR(thisfld, name) \ > - ((thisfld).bitsize = -2, FIELD_PHYSADDR(thisfld) = (name)) > + ((thisfld).static_kind = 2, FIELD_PHYSADDR(thisfld) = (name)) > #define TYPE_FIELD(thistype, n) TYPE_MAIN_TYPE(thistype)->fields[n] > #define TYPE_FIELD_TYPE(thistype, n) FIELD_TYPE(TYPE_FIELD(thistype, n)) > #define TYPE_FIELD_NAME(thistype, n) FIELD_NAME(TYPE_FIELD(thistype, n)) > @@ -840,8 +844,9 @@ extern void allocate_cplus_struct_type ( > (TYPE_CPLUS_SPECIFIC(thistype)->virtual_field_bits == NULL ? 0 \ > : B_TST(TYPE_CPLUS_SPECIFIC(thistype)->virtual_field_bits, (n))) > > -#define TYPE_FIELD_STATIC(thistype, n) (TYPE_MAIN_TYPE (thistype)->fields[n].bitsize < 0) > -#define TYPE_FIELD_STATIC_HAS_ADDR(thistype, n) (TYPE_MAIN_TYPE (thistype)->fields[n].bitsize == -2) > +#define TYPE_FIELD_STATIC(thistype, n) (TYPE_MAIN_TYPE (thistype)->fields[n].static_kind != 0) > +#define TYPE_FIELD_STATIC_KIND(thistype, n) TYPE_MAIN_TYPE (thistype)->fields[n].static_kind > +#define TYPE_FIELD_STATIC_HAS_ADDR(thistype, n) (TYPE_MAIN_TYPE (thistype)->fields[n].static_kind == 2) > #define TYPE_FIELD_STATIC_PHYSNAME(thistype, n) FIELD_PHYSNAME(TYPE_FIELD(thistype, n)) > #define TYPE_FIELD_STATIC_PHYSADDR(thistype, n) FIELD_PHYSADDR(TYPE_FIELD(thistype, n)) > > Index: hpread.c > =================================================================== > RCS file: /cvs/src/src/gdb/hpread.c,v > retrieving revision 1.22 > diff -u -p -r1.22 hpread.c > --- hpread.c 4 Aug 2002 19:11:12 -0000 1.22 > +++ hpread.c 30 Sep 2002 00:43:35 -0000 > @@ -3186,6 +3186,7 @@ hpread_read_enum_type (dnttpointer hp_ty > TYPE_FIELD_NAME (type, n) = SYMBOL_NAME (xsym); > TYPE_FIELD_BITPOS (type, n) = SYMBOL_VALUE (xsym); > TYPE_FIELD_BITSIZE (type, n) = 0; > + TYPE_FIELD_STATIC_KIND (type, n) = 0; > } > if (syms == osyms) > break; > @@ -3347,6 +3348,7 @@ hpread_read_function_type (dnttpointer h > TYPE_FIELD_TYPE (type, n) = SYMBOL_TYPE (xsym); > TYPE_FIELD_ARTIFICIAL (type, n) = 0; > TYPE_FIELD_BITSIZE (type, n) = 0; > + TYPE_FIELD_STATIC_KIND (type, n) = 0; > } > } > /* Mark it as having been processed */ > @@ -3520,6 +3522,7 @@ hpread_read_doc_function_type (dnttpoint > TYPE_FIELD_TYPE (type, n) = SYMBOL_TYPE (xsym); > TYPE_FIELD_ARTIFICIAL (type, n) = 0; > TYPE_FIELD_BITSIZE (type, n) = 0; > + TYPE_FIELD_STATIC_KIND (type, n) = 0; > } > } > > @@ -3704,6 +3707,7 @@ hpread_read_struct_type (dnttpointer hp_ > list = new; > > FIELD_BITSIZE (list->field) = 0; > + FIELD_STATIC_KIND (list->field) = 0; > > /* The "classname" field is actually a DNTT pointer to the base class */ > baseclass = hpread_type_lookup (parentp->dinheritance.classname, > @@ -4101,6 +4105,7 @@ hpread_read_struct_type (dnttpointer hp_ > list->field.name = VT (objfile) + fn_fieldp->dsvar.name; > FIELD_BITPOS (list->field) = 0; /* FIXME is this always true? */ > FIELD_BITSIZE (list->field) = 0; /* use length from type */ > + FIELD_STATIC_KIND (list->field) = 0; > memtype = hpread_type_lookup (fn_fieldp->dsvar.type, objfile); > list->field.type = memtype; > list->attributes = 0; > @@ -4120,6 +4125,7 @@ hpread_read_struct_type (dnttpointer hp_ > list->field.name = VT (objfile) + fn_fieldp->ddvar.name; > FIELD_BITPOS (list->field) = 0; /* FIXME is this always true? */ > FIELD_BITSIZE (list->field) = 0; /* use length from type */ > + FIELD_STATIC_KIND (list->field) = 0; > memtype = hpread_type_lookup (fn_fieldp->ddvar.type, objfile); > list->field.type = memtype; > list->attributes = 0; > @@ -4168,6 +4174,7 @@ hpread_read_struct_type (dnttpointer hp_ > > > /* A FIELD by itself (without a GENFIELD) can also be a static member */ > + FIELD_STATIC_KIND (list->field) = 0; > if (fieldp->dfield.staticmem) > { > FIELD_BITPOS (list->field) = -1; > Index: mdebugread.c > =================================================================== > RCS file: /cvs/src/src/gdb/mdebugread.c,v > retrieving revision 1.29 > diff -u -p -r1.29 mdebugread.c > --- mdebugread.c 18 Sep 2002 20:47:39 -0000 1.29 > +++ mdebugread.c 30 Sep 2002 00:43:36 -0000 > @@ -1092,6 +1092,7 @@ parse_symbol (SYMR *sh, union aux_ext *a > FIELD_TYPE (*f) = t; > FIELD_NAME (*f) = debug_info->ss + cur_fdr->issBase + tsym.iss; > FIELD_BITSIZE (*f) = 0; > + FIELD_STATIC_KIND (*f) = 0; > > enum_sym = ((struct symbol *) > obstack_alloc (¤t_objfile->symbol_obstack, > @@ -1284,6 +1285,7 @@ parse_symbol (SYMR *sh, union aux_ext *a > bitsize = 0; > FIELD_TYPE (*f) = parse_type (cur_fd, ax, sh->index, &bitsize, bigend, name); > FIELD_BITSIZE (*f) = bitsize; > + FIELD_STATIC_KIND (*f) = 0; > break; > > case stIndirect: /* forward declaration on Irix5 */ > -- Daniel Jacobowitz MontaVista Software Debian GNU/Linux Developer