From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <4BCC9ADA.2020909@domain.hid> Date: Mon, 19 Apr 2010 20:03:06 +0200 From: Gilles Chanteperdrix MIME-Version: 1.0 References: <4BCC619E.2@domain.hid> <4BCC6CEE.70907@domain.hid> <4BCC6E3C.3090301@domain.hid> <4BCC7092.1030809@domain.hid> <4BCC71AF.4030903@domain.hid> <4BCC77BD.9040900@domain.hid> <4BCC78D5.3010405@domain.hid> <4BCC7D88.4070403@domain.hid> <1271693411.16659.128.camel@domain.hid> <4BCC814C.6050003@domain.hid> <4BCC8484.1020108@domain.hid> <4BCC9107.1080605@domain.hid> <4BCC9247.10709@domain.hid> <4BCC9628.7030809@domain.hid> In-Reply-To: <4BCC9628.7030809@domain.hid> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Subject: Re: [Xenomai-core] [RFC] fix XENO_OPT_DEBUG bugs. List-Id: Xenomai life and development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Jan Kiszka Cc: xenomai-core Jan Kiszka wrote: > Gilles Chanteperdrix wrote: >> Jan Kiszka wrote: >>> Gilles Chanteperdrix wrote: >>>> Jan Kiszka wrote: >>>>> Philippe Gerum wrote: >>>>>>>>> config XENO_OPT_DEBUG_FOO >>>>>>>>> bool "..." >>>>>>>>> >>>>>>>>> config XENO_OPT_DEBUG_FOO_P >>>>>>>>> int >>>>>>>>> default "1" if XENO_OPT_DEBUG_FOO >>>>>>>>> default "0" >>>>>>>>> >>>>>>>>> and XENO_DEBUG() could be extended to test for >>>>>>>>> CONFIG_XENO_OPT_DEBUG_FOO_P when given "FOO". I'm just not sure= if this >>>>>>>>> can be expressed for legacy 2.4 kernels, so it might have to wa= it for >>>>>>>>> Xenomai 3. >>>>>> Well, actually, I would not merge this in Xenomai 3. I find this r= ather >>>>>> overkill; mainline first I mean, and mainline, i.e. the Xenomai co= de >>>>>> base only requires a simple and straightforward way to get debug >>>>>> switches right. Having to make Kconfig a kitchen sink for some unk= nown >>>>>> out of tree modules to be happy is not really my preferred approac= h in >>>>>> this particular case. >>>>>> >>>>>> Don't get me wrong, I'm not opposed to a more decentralized approa= ch on >>>>>> the paper, it's just that I only care about the mainline tree here= =2E >>>>> The point is not out-of-tree but robustness. Neither the current >>>>> decentralized #ifdef-#define nor its centralized brother meet this >>>>> criteria. An approach like the above which forces you to provide al= l >>>>> required bits before any of the cases (disabled/enabled) starts to = work >>>>> does so. >>>> Ok. What about: >>>> >>>> #define __name2(a, b) a ## b >>>> #define name2(a, b) __name2(a, b) >>>> >>>> #define DECLARE_ASSERT_SYMBOL(sym) \ >>>> static const int CONFIG_XENO_OPT_DEBUG_##sym##0 =3D 0, \ >>>> __CONFIG_XENO_OPT_DEBUG_##sym =3D name2(CONFIG_XENO_OPT_DEBUG_##sy= m, 0) >>>> >>>> #define XENO_ASSERT(subsystem,cond,action) do { \ >>>> if (unlikely(__CONFIG_XENO_OPT_DEBUG_##subsystem > 0 && !(cond))= ) { \ >>>> xnarch_trace_panic_freeze(); \ >>>> xnlogerr("assertion failed at %s:%d (%s)\n", __FILE__, __LIN= E__, (#cond)); \ >>>> xnarch_trace_panic_dump(); \ >>>> action; \ >>>> } \ >>>> } while(0) >>>> >>>> DECLARE_ASSERT_SYMBOL(NUCLEUS); >>>> >>>> It fails to compile when the debug symbol is set and >>>> DECLARE_ASSERT_SYMBOL is missing, which plugs the failure of my prev= ious >>>> attempt. >>> I'm still wrapping my head around this. What would be the usage, >>> >>> #ifndef CONFIG_XENO_OPT_DEBUG_FOO >>> #define CONFIG_XENO_OPT_DEBUG_FOO 0 >>> #endif >>> >>> DECLARE_ASSERT_SYMBOL(FOO); >>> >>> ? If the compiler is smart enough to still drop the asserts based on >>> static const, I'm fine as this is an improvement. >> No, you just use DECLARE_ASSERT_SYMBOL(FOO) >=20 > Would be nice - if it worked. >=20 >>> Still, IMHO, this solution would not even win the second league beaut= y >>> contest (now it comes with as many additional lines as the >>> Kconfig-approach). >> Yes, it is not pretty but to add a config option you just add the usua= l >> Kconfig stuff, then DECLARE_ASSERT_SYMBOL in the code instead of the >> #ifndef #define foo 0 #endif. >> >> If you do not do it, you get a compilation error whether the option is= >> enabled or not. >> >> It can be decentralized, the find | grep mentioned earlier will still = work. >=20 > If we can make it work like that, I'm all for it. But: >=20 > error: initializer element is not constant > (when disabled) >=20 > or >=20 > error: =E2=80=98y0=E2=80=99 undeclared here (not in a function) > (when enabled) >=20 > I'm afraid the preprocessor is not powerful enough for this task (we > would need macros that include preprocessor conditionals). The following seems to work for me: #define __name2(a, b) a ## b #define name2(a, b) __name2(a, b) #define DECLARE_ASSERT_SYMBOL(sym) \= static const int CONFIG_XENO_OPT_DEBUG_##sym##0 =3D 0 #define XENO_DEBUG(sym) (name2(CONFIG_XENO_OPT_DEBUG_##sym,0) > 0) #define XENO_ASSERT(subsystem,cond,action) do { \ if (unlikely(XENO_DEBUG(subsystem) && !(cond))) { \ xnarch_trace_panic_freeze(); \ xnlogerr("assertion failed at %s:%d (%s)\n", __FILE__, __LINE__, = (#cond)); \ xnarch_trace_panic_dump(); \ action; \ } \ } while(0) DECLARE_ASSERT_SYMBOL(NUCLEUS); >=20 > Jan >=20 --=20 Gilles.