Re: New warning in GDB 7.5

[Jan Kratochvil <jan.kratochvil@redhat.com>]

On Sun, 19 Aug 2012 21:10:49 +0200, Mark Kettenis wrote:
>     set $tem = (struct Lisp_Symbol *) $ptr
> 
> probably won't trigger a full symbol read since "struct Lisp_Symbol"
> is a type and not a function or variable.

It will, because GDB generates symbols for each type.  See for example:
process_structure_scope -> new_symbol_full <DW_TAG_structure_type> ->
-> add_symbol_to_list

It should work without any stub 'set' commands, if it does not one should have
a reproducer (one can download Emacs but a minimal reproducer would be
better).


Regards,
Jan


struct s { int i; } v;
gdb -ex r --args ./gdb ./63.o 
Reading symbols from /home/jkratoch/redhat/gdb-clean/gdb/63.o...done.
(gdb) maintenance info psymtabs 
{ objfile /home/jkratoch/redhat/gdb-clean/gdb/63.o ((struct objfile *) 0x2224c80)
  { psymtab 63.c ((struct partial_symtab *) 0x2218dc0)
    readin no
    fullname (null)
    text addresses 0x0 -- 0x0
    psymtabs_addrmap_supported yes
    globals (* (struct partial_symbol **) 0x221a780 @ 1)
    statics (* (struct partial_symbol **) 0x222fe50 @ 2)
    dependencies (none)
  }
}
(gdb) maintenance info symtabs 
(gdb) 
Program received signal SIGINT, Interrupt.
0x00007ffff638dd30 in __poll_nocancel () at ../sysdeps/unix/syscall-template.S:81
81	T_PSEUDO (SYSCALL_SYMBOL, SYSCALL_NAME, SYSCALL_NARGS)
# global symbol
(gdb) p *(* (struct partial_symbol **) 0x221a780 @ 1)[0]
$3 = {ginfo = {name = 0x2218d5a "v", value = {ivalue = 0, block = 0x0, bytes = 0x0, address = 0, chain = 0x0}, language_specific = {mangled_lang = {
        demangled_name = 0x0}, cplus_specific = 0x0}, language = language_c, section = 0, obj_section = 0x0}, domain = VAR_DOMAIN, aclass = LOC_STATIC}
# static symbol
(gdb) p *(* (struct partial_symbol **) 0x222fe50 @ 2)[0]
$5 = {ginfo = {name = 0x2218d55 "int", value = {ivalue = 0, block = 0x0, bytes = 0x0, address = 0, chain = 0x0}, language_specific = {mangled_lang = {
        demangled_name = 0x0}, cplus_specific = 0x0}, language = language_c, section = 0, obj_section = 0x0}, domain = VAR_DOMAIN, aclass = LOC_TYPEDEF}
# static symbol
(gdb) p *(* (struct partial_symbol **) 0x222fe50 @ 2)[1]
$6 = {ginfo = {name = 0x2218d3e "s", value = {ivalue = 0, block = 0x0, bytes = 0x0, address = 0, chain = 0x0}, language_specific = {mangled_lang = {
        demangled_name = 0x0}, cplus_specific = 0x0}, language = language_c, section = 0, obj_section = 0x0}, domain = STRUCT_DOMAIN, aclass = LOC_TYPEDEF}
(gdb) c
Continuing.

(gdb) p (struct s *) 0
$1 = (struct s *) 0x0
(gdb) maintenance info symtabs 
{ objfile /home/jkratoch/redhat/gdb-clean/gdb/63.o ((struct objfile *) 0x2224c80)
	{ symtab 63.c ((struct symtab *) 0x2219790)
	  dirname /home/jkratoch/redhat/gdb-clean/gdb
	  fullname (null)
	  blockvector ((struct blockvector *) 0x2219770) (primary)
	  linetable ((struct linetable *) 0x0)
	  debugformat DWARF 2
	}
}