This is the mail archive of the
gdb-patches@sources.redhat.com
mailing list for the GDB project.
Re: [RFA] Fix calling of static C++ member functions
- From: Daniel Jacobowitz <drow at mvista dot com>
- To: "Peter.Schauer" <Peter dot Schauer at Regent dot E-Technik dot TU-Muenchen dot DE>
- Cc: gdb-patches at sources dot redhat dot com
- Date: Fri, 12 Jul 2002 15:15:37 -0400
- Subject: Re: [RFA] Fix calling of static C++ member functions
- References: <20020512022134.GA30626@nevyn.them.org> <200205121948.VAA02252@reisser.regent.e-technik.tu-muenchen.de>
On Sun, May 12, 2002 at 09:48:56PM +0200, Peter.Schauer wrote:
> > I had to make some substantial changes to this. First of all, I wanted
> > to kill the now-obsolete static_memfuncp argument to find_method_list.
> > Secondly, the way you were skipping THIS in typecmp caused segfaults
> > for some methods which only expected one argument. Here's what I
> > checked in.
> >
> > I -think- I'm caught up on all the patches you sent me now, Peter.
>
> Yes you are, thank you very much.
>
> Thanks also for fixing the segfaults, but I'd be interested in an example
> where this happened. I tried to simplify the typcmp logic as much as possible,
> but obviously failed.
>
> One minor nit, the comments should reflect the elimination of static_memfuncp:
I've committed this.
2002-07-12 Peter Schauer <Peter.Schauer@Regent.E-Technik.TU-Muenchen.DE>
* valops.c (find_method_list): Remove comment about
removed STATIC_MEMFUNCP argument.
(value_find_oload_method_list): Likewise.
>
> --- ./valops.c.orig Sun May 12 17:16:37 2002
> +++ ./valops.c Sun May 12 17:55:37 2002
> @@ -2515,7 +2516,6 @@ value_struct_elt (struct value **argp, s
> * ARGP is a pointer to a pointer to a value (the object)
> * METHOD is a string containing the method name
> * OFFSET is the offset within the value
> - * STATIC_MEMFUNCP is set if the method is static
> * TYPE is the assumed type of the object
> * NUM_FNS is the number of overloaded instances
> * BASETYPE is set to the actual type of the subobject where the method is found
> @@ -2606,7 +2606,6 @@ find_method_list (struct value **argp, c
> * ARGP is a pointer to a pointer to a value (the object)
> * METHOD is the method name
> * OFFSET is the offset within the value contents
> - * STATIC_MEMFUNCP is set if the method is static
> * NUM_FNS is the number of overloaded instances
> * BASETYPE is set to the type of the base subobject that defines the method
> * BOFFSET is the offset of the base subobject which defines the method */
>
> Thanks again,
>
> > On Fri, Mar 15, 2002 at 11:44:46AM +0100, Peter.Schauer wrote:
> > > This one fixes
> > > http://sources.redhat.com/ml/bug-gdb/2001-06/msg00059.html
> > > which is still broken in CVS Head GDB.
> > >
> > > Actually there are a bunch problems:
> > >
> > > - The printing of the bad value happens, because find_overload_match does
> > > not set *staticp for static member functions.
> > >
> > > - The crash happens because in
> > > domain = TYPE_DOMAIN_TYPE (fns_ptr[0].type);
> > > in find_overload_match we don't find the domain, as find_method_list
> > > doesn't handle stub methods correctly and it's too late in
> > > find_overload_match. Checking for stub methods in find_method_list
> > > instead gets rid of the crash.
> > >
> > > - When trying the provided testcase for dwarf2, more problems arise.
> > > Until now check_stub_method did not handle static member
> > > functions correctly, as the this parameter was added unconditionally.
> > > After fixing this, we also have to adjust typecmp, so that static
> > > member functions also work with `set overload off'.
> > > And finally we have to fix find_overload_match, to make it behave properly
> > > in the `set overload on' case.
> > >
> > > The patch below fixes the calling of static member functions for
> > > gcc-2.95.2/gcc-3.x and stabs/dwarf2 debugging, ok to commit ?
> >
> > I had to make some substantial changes to this. First of all, I wanted
> > to kill the now-obsolete static_memfuncp argument to find_method_list.
> > Secondly, the way you were skipping THIS in typecmp caused segfaults
> > for some methods which only expected one argument. Here's what I
> > checked in.
> >
> > I -think- I'm caught up on all the patches you sent me now, Peter.
> >
> > > 2002-03-15 Peter Schauer <pes@regent.e-technik.tu-muenchen.de>
> > >
> > > Fix calling of static member functions.
> > > * gdbtypes.c (check_stub_method): Handle static member functions.
> > > * valops.c (typecmp): Handle static member functions correctly.
> > > (find_overload_match): Ditto, set *staticp for static member
> > > functions.
> > > (find_method_list): Check for stub functions here, not in
> > > find_overload_match.
> >
> > --
> > Daniel Jacobowitz Carnegie Mellon University
> > MontaVista Software Debian GNU/Linux Developer
> >
> > 2005-05-11 Daniel Jacobowitz <drow@mvista.com>
> > Peter Schauer <pes@regent.e-technik.tu-muenchen.de>
> >
> > * Makefile.in: Update dependencies for valops.c.
> > * valops.c: Include "gdb_assert.h".
> > (typecmp): Skip THIS parameter to methods.
> > (find_method_list): Remove static_memfuncp argument,
> > update callers. Check for stub methods.
> > (find_value_oload_method_list): Don't set *static_memfuncp.
> > (find_overload_match): Don't check for stub methods. Assert
> > that methods are not stubbed. Handle static methods.
> > (value_find_oload_method_list): Remove static_memfuncp argument.
> > * gdbtypes.c (check_stub_method): Do not add THIS pointer
> > to the argument list for static stub methods.
> > * value.h (value_find_oload_method_list): Update prototype.
> >
> > Index: valops.c
> > ===================================================================
> > RCS file: /cvs/src/src/gdb/valops.c,v
> > retrieving revision 1.56
> > diff -u -p -r1.56 valops.c
> > --- valops.c 2 May 2002 19:00:36 -0000 1.56
> > +++ valops.c 12 May 2002 02:08:08 -0000
> > @@ -36,6 +36,7 @@
> >
> > #include <errno.h>
> > #include "gdb_string.h"
> > +#include "gdb_assert.h"
> >
> > /* Flag indicating HP compilers were used; needed to correctly handle some
> > value operations with HP aCC code/runtime. */
> > @@ -66,7 +67,7 @@ static CORE_ADDR allocate_space_in_infer
> > static struct value *cast_into_complex (struct type *, struct value *);
> >
> > static struct fn_field *find_method_list (struct value ** argp, char *method,
> > - int offset, int *static_memfuncp,
> > + int offset,
> > struct type *type, int *num_fns,
> > struct type **basetype,
> > int *boffset);
> > @@ -1963,10 +1964,13 @@ typecmp (int staticp, struct type *t1[],
> > return t2[1] != 0;
> > if (t1 == 0)
> > return 1;
> > - if (TYPE_CODE (t1[0]) == TYPE_CODE_VOID)
> > - return 0;
> > if (t1[!staticp] == 0)
> > return 0;
> > + if (TYPE_CODE (t1[0]) == TYPE_CODE_VOID)
> > + return 0;
> > + /* Skip ``this'' argument if applicable. T2 will always include THIS. */
> > + if (staticp)
> > + t2++;
> > for (i = !staticp; t1[i] && TYPE_CODE (t1[i]) != TYPE_CODE_VOID; i++)
> > {
> > struct type *tt1, *tt2;
> > @@ -2520,7 +2524,7 @@ value_struct_elt (struct value **argp, s
> >
> > static struct fn_field *
> > find_method_list (struct value **argp, char *method, int offset,
> > - int *static_memfuncp, struct type *type, int *num_fns,
> > + struct type *type, int *num_fns,
> > struct type **basetype, int *boffset)
> > {
> > int i;
> > @@ -2536,10 +2540,22 @@ find_method_list (struct value **argp, c
> > char *fn_field_name = TYPE_FN_FIELDLIST_NAME (type, i);
> > if (fn_field_name && (strcmp_iw (fn_field_name, method) == 0))
> > {
> > - *num_fns = TYPE_FN_FIELDLIST_LENGTH (type, i);
> > + /* Resolve any stub methods. */
> > + int len = TYPE_FN_FIELDLIST_LENGTH (type, i);
> > + struct fn_field *f = TYPE_FN_FIELDLIST1 (type, i);
> > + int j;
> > +
> > + *num_fns = len;
> > *basetype = type;
> > *boffset = offset;
> > - return TYPE_FN_FIELDLIST1 (type, i);
> > +
> > + for (j = 0; j < len; j++)
> > + {
> > + if (TYPE_FN_FIELD_STUB (f, j))
> > + check_stub_method (type, i, j);
> > + }
> > +
> > + return f;
> > }
> > }
> >
> > @@ -2579,7 +2595,8 @@ find_method_list (struct value **argp, c
> > base_offset = TYPE_BASECLASS_BITPOS (type, i) / 8;
> > }
> > f = find_method_list (argp, method, base_offset + offset,
> > - static_memfuncp, TYPE_BASECLASS (type, i), num_fns, basetype, boffset);
> > + TYPE_BASECLASS (type, i), num_fns, basetype,
> > + boffset);
> > if (f)
> > return f;
> > }
> > @@ -2597,8 +2614,8 @@ find_method_list (struct value **argp, c
> >
> > struct fn_field *
> > value_find_oload_method_list (struct value **argp, char *method, int offset,
> > - int *static_memfuncp, int *num_fns,
> > - struct type **basetype, int *boffset)
> > + int *num_fns, struct type **basetype,
> > + int *boffset)
> > {
> > struct type *t;
> >
> > @@ -2621,12 +2638,7 @@ value_find_oload_method_list (struct val
> > && TYPE_CODE (t) != TYPE_CODE_UNION)
> > error ("Attempt to extract a component of a value that is not a struct or union");
> >
> > - /* Assume it's not static, unless we see that it is. */
> > - if (static_memfuncp)
> > - *static_memfuncp = 0;
> > -
> > - return find_method_list (argp, method, 0, static_memfuncp, t, num_fns, basetype, boffset);
> > -
> > + return find_method_list (argp, method, 0, t, num_fns, basetype, boffset);
> > }
> >
> > /* Given an array of argument types (ARGTYPES) (which includes an
> > @@ -2685,6 +2697,7 @@ find_overload_match (struct type **arg_t
> > int boffset;
> > register int jj;
> > register int ix;
> > + int static_offset;
> >
> > char *obj_type_name = NULL;
> > char *func_name = NULL;
> > @@ -2692,9 +2705,6 @@ find_overload_match (struct type **arg_t
> > /* Get the list of overloaded methods or functions */
> > if (method)
> > {
> > - int i;
> > - int len;
> > - struct type *domain;
> > obj_type_name = TYPE_NAME (VALUE_TYPE (obj));
> > /* Hack: evaluate_subexp_standard often passes in a pointer
> > value rather than the object itself, so try again */
> > @@ -2703,7 +2713,6 @@ find_overload_match (struct type **arg_t
> > obj_type_name = TYPE_NAME (TYPE_TARGET_TYPE (VALUE_TYPE (obj)));
> >
> > fns_ptr = value_find_oload_method_list (&temp, name, 0,
> > - staticp,
> > &num_fns,
> > &basetype, &boffset);
> > if (!fns_ptr || !num_fns)
> > @@ -2711,26 +2720,10 @@ find_overload_match (struct type **arg_t
> > obj_type_name,
> > (obj_type_name && *obj_type_name) ? "::" : "",
> > name);
> > - domain = TYPE_DOMAIN_TYPE (fns_ptr[0].type);
> > - len = TYPE_NFN_FIELDS (domain);
> > - /* NOTE: dan/2000-03-10: This stuff is for STABS, which won't
> > - give us the info we need directly in the types. We have to
> > - use the method stub conversion to get it. Be aware that this
> > - is by no means perfect, and if you use STABS, please move to
> > - DWARF-2, or something like it, because trying to improve
> > - overloading using STABS is really a waste of time. */
> > - for (i = 0; i < len; i++)
> > - {
> > - int j;
> > - struct fn_field *f = TYPE_FN_FIELDLIST1 (domain, i);
> > - int len2 = TYPE_FN_FIELDLIST_LENGTH (domain, i);
> > -
> > - for (j = 0; j < len2; j++)
> > - {
> > - if (TYPE_FN_FIELD_STUB (f, j) && (!strcmp_iw (TYPE_FN_FIELDLIST_NAME (domain,i),name)))
> > - check_stub_method (domain, i, j);
> > - }
> > - }
> > + /* If we are dealing with stub method types, they should have
> > + been resolved by find_method_list via value_find_oload_method_list
> > + above. */
> > + gdb_assert (TYPE_DOMAIN_TYPE (fns_ptr[0].type) != NULL);
> > }
> > else
> > {
> > @@ -2757,10 +2750,11 @@ find_overload_match (struct type **arg_t
> > /* Consider each candidate in turn */
> > for (ix = 0; ix < num_fns; ix++)
> > {
> > + static_offset = 0;
> > if (method)
> > {
> > - /* For static member functions, we won't have a this pointer, but nothing
> > - else seems to handle them right now, so we just pretend ourselves */
> > + if (TYPE_FN_FIELD_STATIC_P (fns_ptr, ix))
> > + static_offset = 1;
> > nparms=0;
> >
> > if (TYPE_FN_FIELD_ARGS(fns_ptr,ix))
> > @@ -2782,8 +2776,10 @@ find_overload_match (struct type **arg_t
> > ? (TYPE_FN_FIELD_ARGS (fns_ptr, ix)[jj])
> > : TYPE_FIELD_TYPE (SYMBOL_TYPE (oload_syms[ix]), jj));
> >
> > - /* Compare parameter types to supplied argument types */
> > - bv = rank_function (parm_types, nparms, arg_types, nargs);
> > + /* Compare parameter types to supplied argument types. Skip THIS for
> > + static methods. */
> > + bv = rank_function (parm_types, nparms, arg_types + static_offset,
> > + nargs - static_offset);
> >
> > if (!oload_champ_bv)
> > {
> > @@ -2821,7 +2817,7 @@ find_overload_match (struct type **arg_t
> > fprintf_filtered (gdb_stderr,"Overloaded method instance %s, # of parms %d\n", fns_ptr[ix].physname, nparms);
> > else
> > fprintf_filtered (gdb_stderr,"Overloaded function instance %s # of parms %d\n", SYMBOL_DEMANGLED_NAME (oload_syms[ix]), nparms);
> > - for (jj = 0; jj < nargs; jj++)
> > + for (jj = 0; jj < nargs - static_offset; jj++)
> > fprintf_filtered (gdb_stderr,"...Badness @ %d : %d\n", jj, bv->rank[jj]);
> > fprintf_filtered (gdb_stderr,"Overload resolution champion is %d, ambiguous? %d\n", oload_champ, oload_ambiguous);
> > }
> > @@ -2844,8 +2840,11 @@ find_overload_match (struct type **arg_t
> > }
> > #endif
> >
> > - /* Check how bad the best match is */
> > - for (ix = 1; ix <= nargs; ix++)
> > + /* Check how bad the best match is. */
> > + static_offset = 0;
> > + if (method && TYPE_FN_FIELD_STATIC_P (fns_ptr, oload_champ))
> > + static_offset = 1;
> > + for (ix = 1; ix <= nargs - static_offset; ix++)
> > {
> > if (oload_champ_bv->rank[ix] >= 100)
> > oload_incompatible = 1; /* truly mismatched types */
> > @@ -2878,6 +2877,10 @@ find_overload_match (struct type **arg_t
> >
> > if (method)
> > {
> > + if (staticp && TYPE_FN_FIELD_STATIC_P (fns_ptr, oload_champ))
> > + *staticp = 1;
> > + else if (staticp)
> > + *staticp = 0;
> > if (TYPE_FN_FIELD_VIRTUAL_P (fns_ptr, oload_champ))
> > *valp = value_virtual_fn_field (&temp, fns_ptr, oload_champ, basetype, boffset);
> > else
> > Index: gdbtypes.c
> > ===================================================================
> > RCS file: /cvs/src/src/gdb/gdbtypes.c,v
> > retrieving revision 1.48
> > diff -u -p -r1.48 gdbtypes.c
> > --- gdbtypes.c 8 May 2002 22:58:39 -0000 1.48
> > +++ gdbtypes.c 12 May 2002 02:08:09 -0000
> > @@ -1649,9 +1649,16 @@ check_stub_method (struct type *type, in
> > argtypes = (struct type **)
> > TYPE_ALLOC (type, (argcount + 2) * sizeof (struct type *));
> > p = argtypetext;
> > - /* FIXME: This is wrong for static member functions. */
> > - argtypes[0] = lookup_pointer_type (type);
> > - argcount = 1;
> > +
> > + /* Add THIS pointer for non-static methods. */
> > + f = TYPE_FN_FIELDLIST1 (type, method_id);
> > + if (TYPE_FN_FIELD_STATIC_P (f, signature_id))
> > + argcount = 0;
> > + else
> > + {
> > + argtypes[0] = lookup_pointer_type (type);
> > + argcount = 1;
> > + }
> >
> > if (*p != ')') /* () means no args, skip while */
> > {
> > @@ -1693,8 +1700,6 @@ check_stub_method (struct type *type, in
> > }
> >
> > xfree (demangled_name);
> > -
> > - f = TYPE_FN_FIELDLIST1 (type, method_id);
> >
> > TYPE_FN_FIELD_PHYSNAME (f, signature_id) = mangled_name;
> >
> > Index: value.h
> > ===================================================================
> > RCS file: /cvs/src/src/gdb/value.h,v
> > retrieving revision 1.30
> > diff -u -p -r1.30 value.h
> > --- value.h 11 May 2002 23:48:23 -0000 1.30
> > +++ value.h 12 May 2002 02:08:09 -0000
> > @@ -375,7 +375,7 @@ extern struct value *value_struct_elt_fo
> > extern struct value *value_static_field (struct type *type, int fieldno);
> >
> > extern struct fn_field *value_find_oload_method_list (struct value **, char *,
> > - int, int *, int *,
> > + int, int *,
> > struct type **, int *);
> >
> > extern int find_overload_match (struct type **arg_types, int nargs,
> > Index: Makefile.in
> > ===================================================================
> > RCS file: /cvs/src/src/gdb/Makefile.in,v
> > retrieving revision 1.185
> > diff -u -p -r1.185 Makefile.in
> > --- Makefile.in 11 May 2002 23:14:25 -0000 1.185
> > +++ Makefile.in 12 May 2002 02:16:43 -0000
> > @@ -2144,7 +2144,7 @@ valarith.o: valarith.c $(bfd_h) $(defs_h
> > $(gdb_string_h) $(doublest_h)
> >
> > valops.o: valops.c $(defs_h) $(gdbcore_h) $(inferior_h) $(target_h) \
> > - $(gdb_string_h) $(regcache_h) $(cp_abi_h)
> > + $(gdb_string_h) $(regcache_h) $(cp_abi_h) $(gdb_assert_h)
> >
> > valprint.o: valprint.c $(defs_h) $(expression_h) $(gdbcmd_h) \
> > $(gdbcore_h) $(gdbtypes_h) $(language_h) $(symtab_h) $(target_h) \
> >
> >
>
>
> --
> Peter Schauer pes@regent.e-technik.tu-muenchen.de
>
--
Daniel Jacobowitz Carnegie Mellon University
MontaVista Software Debian GNU/Linux Developer