Re: [Tinycc-devel] tcc 0.9.28rc testing: bug in autoconf 2.71 with AC_CHECK_DEFINE
> > On 24/9/23 11:03, Nick Bowler wrote: > >> The word AC_CHECK_DEFINE is not found anywhere in the Autoconf > >> source code or documentation. > > > > My guess would be that the 3rd party is the autoconf archive because > > they provide both AX_CHECK_DEFINE and AC_CHECK_DEFINE > > > > http://git.savannah.gnu.org/gitweb/?p=autoconf-archive.git;a=blob_plain;f=m4/ax_check_define.m4 > > OK, I see. Thanks Peter. I can confirm, the "autoconf-archive" - Package is installed here. > Ignoring the fact that the this macro definition flagrantly disregards > the Autoconf reserved namespace... That trap catched me. > AC_CHECK_DEFINE here is quoting > inconsistently: $1 is double-quoted in the argument to AC_LANG_PROGRAM, > but it is only single-quoted in the arguments of AS_VAR_PUSHDEF and > AC_CACHE_CHECK. Oh, thanks for the in deepth analysis. I will check to see, how and where i can report this bug. > So no amount of quoting at the call site will ever solve the problem for > Detlef. The suggested workarounds should help. > We can quote __unix__ correctly for AC_LANG_PROGRAM, or we can > quote it for the other expansions, but never both at the same time. > For example: > AC_CHECK_DEFINE([__unix@@__], [...]) > m4_ifdef([__unix__], [m4_define([__unix__], [[__unix__]])])dnl > AC_CHECK_DEFINE([__unix__], [...]) I will try your suggested workarounds. > I don't think there is any regression in Autoconf here, I don't see any > significant difference in behaviour between Autoconf 2.72c, 2.71 or > 2.69. I was not sure, where the bug belongs, and with the "AC_" prefix, i started here. -- Regards ... Detlef ___ Tinycc-devel mailing list Tinycc-devel@nongnu.org https://lists.nongnu.org/mailman/listinfo/tinycc-devel
Re: [Tinycc-devel] tcc 0.9.28rc testing: bug in autoconf 2.71 with AC_CHECK_DEFINE
Thanks Nick and Peter for your analysis. Yes, the "AC_" prefix fooled me, that AC_CHECK_DEFINE belongs to autoconf. > On 2023-09-23, Nick Bowler wrote: > > On 2023-09-23, Detlef Riekenberg wrote: > >> AC_CHECK_DEFINE(__unix, CFLAGS="-DFOUND__unix $CFLAGS") > >> AC_CHECK_DEFINE(__unix__, CFLAGS="-DFOUND__unix__ $CFLAGS") > >> AC_CHECK_DEFINE(__linux__, CFLAGS="-DFOUND__linux__ $CFLAGS") > [...] > > So it sounds like there must be some third party code involved which > > is defining this macro (and this code is defining macros in the AC_* > > namespace to make it look like it came from Autoconf when in fact it > > did not). I can confirm, that i have the "autoconf-archive" package insalled. The installed "/usr/share/aclocal/ax_check_define.m4" contains AC_CHECK_DEFINE and AX_CHECK_DEFINE > Just to add, you don't need any third party macros to check for typical > C predefined macros including __unix, etc. I would write such checks > something like this (untested): > > AC_COMPUTE_INT([unix_val], [__unix], [@@], [unix_val=0]) > AS_IF([test $unix_val -ne 0], > [put code here to run when __unix is defined and is non-zero]) Learned something new. Thanks The magic "[@@]" is really strange. > Hope that helps, Sure. Thanks -- Regards ... Detlef ___ Tinycc-devel mailing list Tinycc-devel@nongnu.org https://lists.nongnu.org/mailman/listinfo/tinycc-devel
Re: [Tinycc-devel] tcc 0.9.28rc testing: bug in autoconf 2.71 with AC_CHECK_DEFINE
On 24/09/2023, Peter Johansson wrote: > Hi Detlef and Nick, > > On 24/9/23 11:03, Nick Bowler wrote: >> The word AC_CHECK_DEFINE is not found anywhere in the Autoconf >> source code or documentation. > > My guess would be that the 3rd party is the autoconf archive because > they provide both AX_CHECK_DEFINE and AC_CHECK_DEFINE > > http://git.savannah.gnu.org/gitweb/?p=autoconf-archive.git;a=blob_plain;f=m4/ax_check_define.m4 OK, I see. So, depending on the system you are running Autoconf on, GNU m4 may pre- define __unix__ as an m4 macro which expands to the empty string. Ignoring the fact that the this macro definition flagrantly disregards the Autoconf reserved namespace... AC_CHECK_DEFINE here is quoting inconsistently: $1 is double-quoted in the argument to AC_LANG_PROGRAM, but it is only single-quoted in the arguments of AS_VAR_PUSHDEF and AC_CACHE_CHECK. So no amount of quoting at the call site will ever solve the problem for Detlef. We can quote __unix__ correctly for AC_LANG_PROGRAM, or we can quote it for the other expansions, but never both at the same time. If unwilling to fix the quoting issues within AC_CHECK_DEFINE, one way to work around the problem is by using a quadrigraph to prevent __unix__ from being recognized as a macro, since quadrigraphs are removed only after all macro processing is complete. For example: AC_CHECK_DEFINE([__unix@@__], [...]) Another option is to redefine __unix__ as this GNU m4 feature seems pretty unlikely to be useful in Autoconf, and even then it seems unlikely to matter exactly what text __unix__ expands to: m4_ifdef([__unix__], [m4_define([__unix__], [[__unix__]])])dnl AC_CHECK_DEFINE([__unix__], [...]) I don't think there is any regression in Autoconf here, I don't see any significant difference in behaviour between Autoconf 2.72c, 2.71 or 2.69. Hope that helps, Nick ___ Tinycc-devel mailing list Tinycc-devel@nongnu.org https://lists.nongnu.org/mailman/listinfo/tinycc-devel
Re: [Tinycc-devel] tcc 0.9.28rc testing: bug in autoconf 2.71 with AC_CHECK_DEFINE
Hi, On 2023-09-23, Detlef Riekenberg wrote: > During testing of tcc 0.9.28rc, > I found a strange bug in autoconf 2.71 with `AC_CHECK_DEFINE` for > `__unix__`. The word AC_CHECK_DEFINE is not found anywhere in the Autoconf source code or documentation. So I am afraid it is a bit difficult to understand this report. [snip] > Please test this snipped with the current 2.72rc: > ``` > AC_CHECK_DEFINE(__unix, CFLAGS="-DFOUND__unix $CFLAGS") > AC_CHECK_DEFINE(__unix__, CFLAGS="-DFOUND__unix__ $CFLAGS") > AC_CHECK_DEFINE(__linux__, CFLAGS="-DFOUND__linux__ $CFLAGS") As expected, if I translate this into an "obvious" configure.ac by adding the mandatory AC_INIT and AC_OUTPUT expansions, I just get: configure.ac:3: error: possibly undefined macro: AC_CHECK_DEFINE [...] So it sounds lkie there must be some third party code involved which is defining this macro (and this code is defining macros in the AC_* namespace to make it look like it came from Autoconf when in fact it did not). That doesn't mean there isn't a bug in Autoconf. It would be helpful if you could produce a complete self-contained test case which demonstrates the problem, one that doesn't depend on code from outside of Autoconf which we don't necessarily have. Cheers, Nick ___ Tinycc-devel mailing list Tinycc-devel@nongnu.org https://lists.nongnu.org/mailman/listinfo/tinycc-devel
Re: [Tinycc-devel] tcc 0.9.28rc testing: bug in autoconf 2.71 with AC_CHECK_DEFINE
On 2023-09-23, Nick Bowler wrote: > On 2023-09-23, Detlef Riekenberg wrote: >> AC_CHECK_DEFINE(__unix, CFLAGS="-DFOUND__unix $CFLAGS") >> AC_CHECK_DEFINE(__unix__, CFLAGS="-DFOUND__unix__ $CFLAGS") >> AC_CHECK_DEFINE(__linux__, CFLAGS="-DFOUND__linux__ $CFLAGS") [...] > So it sounds like there must be some third party code involved which > is defining this macro (and this code is defining macros in the AC_* > namespace to make it look like it came from Autoconf when in fact it > did not). Just to add, you don't need any third party macros to check for typical C predefined macros including __unix, etc. I would write such checks something like this (untested): AC_COMPUTE_INT([unix_val], [__unix], [@@], [unix_val=0]) AS_IF([test $unix_val -ne 0], [put code here to run when __unix is defined and is non-zero]) That works out of the box with Autoconf and should be a very robust check. The third argument to AC_COMPUTE_INT is @@ to prevent Autoconf from inserting the default #includes in the test program. If you need to distinguish the case where __unix may be pre-defined with the value 0 (probably not relevant with this particular macro), then you can tweak the action-if-failed (fourth argument) and if condition a bit. Hope that helps, Nick ___ Tinycc-devel mailing list Tinycc-devel@nongnu.org https://lists.nongnu.org/mailman/listinfo/tinycc-devel
Re: [Tinycc-devel] tcc 0.9.28rc testing: bug in autoconf 2.71 with AC_CHECK_DEFINE
Hi Detlef and Nick, On 24/9/23 11:03, Nick Bowler wrote: The word AC_CHECK_DEFINE is not found anywhere in the Autoconf source code or documentation. My guess would be that the 3rd party is the autoconf archive because they provide both AX_CHECK_DEFINE and AC_CHECK_DEFINE http://git.savannah.gnu.org/gitweb/?p=autoconf-archive.git;a=blob_plain;f=m4/ax_check_define.m4 Cheers, Peter ___ Tinycc-devel mailing list Tinycc-devel@nongnu.org https://lists.nongnu.org/mailman/listinfo/tinycc-devel
[Tinycc-devel] tcc 0.9.28rc testing: bug in autoconf 2.71 with AC_CHECK_DEFINE
Hi autoconf team. During testing of tcc 0.9.28rc, I found a strange bug in autoconf 2.71 with `AC_CHECK_DEFINE` for `__unix__`. For comparsion, i added checks for "__unix" and "__linux__": Overview: * [__unix__] always found, but the log text is crippled * __unix__ never found and the log text is crippled * The second check does not use the cached result from the first check * When i duplicate the tests, the duplicate test used the cached result from the previous check, but all other failures remain. (1: first result: see above, 2: cached result from 1, 3: different result: see above, 4: cached result from 3) I am using tcc 0.9.28rc on linux and gcc 12.3.0 produces the same results. Please test this snipped with the current 2.72rc: ``` AC_CHECK_DEFINE(__unix, CFLAGS="-DFOUND__unix $CFLAGS") AC_CHECK_DEFINE(__unix__, CFLAGS="-DFOUND__unix__ $CFLAGS") AC_CHECK_DEFINE(__linux__, CFLAGS="-DFOUND__linux__ $CFLAGS") AC_CHECK_DEFINE([__unix], CFLAGS="-DFOUNDxx__unix $CFLAGS") AC_CHECK_DEFINE([__unix__], CFLAGS="-DFOUNDxx__unix__ $CFLAGS") AC_CHECK_DEFINE([__linux__], CFLAGS="-DFOUNDxx__linux__ $CFLAGS") ``` buggy results: ``` checking for __unix defined... yes checking for defined... no checking for __linux__ defined... yes checking for __unix defined... (cached) yes checking for defined... yes checking for __linux__ defined... (cached) yes ``` And yes, when the checks are reordered, ``` AC_CHECK_DEFINE([__unix], CFLAGS="-DFOUNDxx__unix $CFLAGS") AC_CHECK_DEFINE([__unix__], CFLAGS="-DFOUNDxx__unix__ $CFLAGS") AC_CHECK_DEFINE([__linux__], CFLAGS="-DFOUNDxx__linux__ $CFLAGS") AC_CHECK_DEFINE(__unix, CFLAGS="-DFOUND__unix $CFLAGS") AC_CHECK_DEFINE(__unix__, CFLAGS="-DFOUND__unix__ $CFLAGS") AC_CHECK_DEFINE(__linux__, CFLAGS="-DFOUND__linux__ $CFLAGS") ``` ... the results are different: ``` checking for __unix defined... yes checking for defined... yes checking for __linux__ defined... yes checking for __unix defined... (cached) yes checking for defined... no checking for __linux__ defined... (cached) yes ``` * What is 2.72rc doing? * Should i add a bug report for 2.71 to document this bug? -- Bye bye ... Detlef ___ Tinycc-devel mailing list Tinycc-devel@nongnu.org https://lists.nongnu.org/mailman/listinfo/tinycc-devel
