Re: [PULL 22/30] gdbstub: only compile gdbstub twice for whole build

["Philippe Mathieu-Daudé" <philmd@linaro.org>]

Hi Alex, Paolo,

On 7/3/23 22:21, Alex Bennée wrote:
> Now we have removed any target specific bits from the core gdbstub
> code we only need to build it twice. We have to jump a few meson hoops
> to manually define the CONFIG_USER_ONLY symbol but it seems to work.
> 
> Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
> Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
> Message-Id: <20230302190846.2593720-23-alex.bennee@linaro.org>
> Message-Id: <20230303025805.625589-23-richard.henderson@linaro.org>
> 
> diff --git a/gdbstub/gdbstub.c b/gdbstub/gdbstub.c
> index e264ed04e7..d9e9bf9294 100644
> --- a/gdbstub/gdbstub.c
> +++ b/gdbstub/gdbstub.c
> @@ -39,9 +39,7 @@
>   
>   #include "sysemu/hw_accel.h"
>   #include "sysemu/runstate.h"
> -#include "exec/exec-all.h"
>   #include "exec/replay-core.h"
> -#include "exec/tb-flush.h"
>   #include "exec/hwaddr.h"
>   
>   #include "internals.h"
> @@ -1612,7 +1610,7 @@ static const GdbCmdParseEntry gdb_gen_query_table[] = {
>           .cmd_startswith = 1,
>           .schema = "s:l,l0"
>       },
> -#if defined(CONFIG_USER_ONLY) && defined(CONFIG_LINUX_USER)
> +#if defined(CONFIG_USER_ONLY) && defined(CONFIG_LINUX)
>       {
>           .handler = gdb_handle_query_xfer_auxv,
>           .cmd = "Xfer:auxv:read::",
> diff --git a/gdbstub/meson.build b/gdbstub/meson.build
> index c876222b9c..d679c7ab86 100644
> --- a/gdbstub/meson.build
> +++ b/gdbstub/meson.build
> @@ -4,13 +4,35 @@
>   # types such as hwaddr.
>   #
>   
> -specific_ss.add(files('gdbstub.c'))
> +# We need to build the core gdb code via a library to be able to tweak
> +# cflags so:
> +
> +gdb_user_ss = ss.source_set()
> +gdb_softmmu_ss = ss.source_set()
> +
> +# We build two versions of gdbstub, one for each mode
> +gdb_user_ss.add(files('gdbstub.c', 'user.c'))
> +gdb_softmmu_ss.add(files('gdbstub.c', 'softmmu.c'))
> +
> +gdb_user_ss = gdb_user_ss.apply(config_host, strict: false)
> +gdb_softmmu_ss = gdb_softmmu_ss.apply(config_host, strict: false)
> +
> +libgdb_user = static_library('gdb_user',
> +                             gdb_user_ss.sources() + genh,
> +                             name_suffix: 'fa',
> +                             c_args: '-DCONFIG_USER_ONLY')

FYI building configured as '--disable-user --disable-tcg' I still see:

[13/810] Compiling C object gdbstub/libgdb_user.fa.p/gdbstub.c.o

> +libgdb_softmmu = static_library('gdb_softmmu',
> +                                gdb_softmmu_ss.sources() + genh,
> +                                name_suffix: 'fa')
> +
> +gdb_user = declare_dependency(link_whole: libgdb_user)
> +user_ss.add(gdb_user)

Later we have:

common_ss.add_all(when: 'CONFIG_USER_ONLY', if_true: user_ss)

Also:

config_all += {
   'CONFIG_SOFTMMU': have_system,
   'CONFIG_USER_ONLY': have_user,
   'CONFIG_ALL': true,
}

Why is libgdb_user.fa built while using --disable-user
(have_user=false)?

> +gdb_softmmu = declare_dependency(link_whole: libgdb_softmmu)
> +softmmu_ss.add(gdb_softmmu)
>   
>   # These have to built to the target ABI
>   specific_ss.add(files('syscalls.c'))
>   
> -softmmu_ss.add(files('softmmu.c'))
> -user_ss.add(files('user.c'))
> -
>   # The user-target is specialised by the guest
>   specific_ss.add(when: 'CONFIG_USER_ONLY', if_true: files('user-target.c'))