----- Original Message -----
> Hello Dave,
>
> The patch attached with this mail is to add "-s" option for struct
> command. The output is like below.
>
> crash> page.private,_mapcount.counter,lru.next -s ffffea0000000850
> 0 -1 0xffffea0000000878
> crash> page.private,_mapcount.counter,lru.next -s ffffea0000000850 -h
> 0x0 0xffffffff 0xffffea0000000878
>
> There are three features provided by the patches.
>
> 1. the data can be output in one line, easier to be parsed
>
> 2. it is extremly faster than original struct command and print command.
> When using command like "struct xxx.yyy -s < address_list", if there are
> lots of addresses in the file, address_list, the original struct command
> will spend several minutes and even several hours. But the patch will
> reduce the time to several seconds.
>
> 3. submember can also be output, like "_mapcount.counter" int the above example
>
> P.S.
> The first patch is used to modified gdb. It add a command called
> "printm", which can output the relative information of a struct's
> member.
In our original discussions, i thought that I had made it clear that
the introduction of a new option paradigm with submembers could be
avoided by using, for example, "page._mapcounter" instead of having
to enter "page._mapcount.counter"? This option makes the struct
command seemingly violate its own rules, and really confuses things.
For example, with your patch, a user would see things like this:
crash> page._mapcount.counter ffffea0000000508 -s
-1
crash> page._mapcount.counter ffffea0000000508
struct: invalid format: page._mapcount.counter
crash> page._mapcount ffffea0000000508
_mapcount = {
counter = -1
}
crash> page._mapcount ffffea0000000508 -s
struct: invalid data structure reference page._mapcount
crash>
I had suggested that you look into the get_member_data() function
in to the gdb/symtab.c file to access the member offset and size
values.
I also don't like the idea of modifying the prototype of
the stalwart print_command_1() gdb function, and the creation
of a new gdb command. Whenever there is a need to update the
embedded gdb version, patches like this can be problematic.
I would prefer that you create a new "GNU_XXXX" #define,
similar to GNU_GET_SYMBOL_TYPE, pass the request through
the gdb_command_funnel switch statement, and write a new
standalone function to accomplish what you have done in the
print_command_1() function.
Dave
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