Re: [Tinycc-devel] Add max_align_t to stddef.h and C11

[Christian Jullien]

Don't worry Matthias, this how we can make a better tcc. Thank you for the 
revert.

-----Original Message-----
From: Tinycc-devel [mailto:address@hidden On Behalf Of uso ewin
Sent: vendredi 11 janvier 2019 10:41
To: address@hidden
Subject: Re: [Tinycc-devel] Add max_align_t to stddef.h and C11

On Fri, Jan 11, 2019 at 7:56 AM Christian Jullien <address@hidden> wrote:
>
> Petr, I also agree with you.
>
> If gcc more or less "governs" tcc behavior,  _Alignof and _Generic should be
> defined by default whatever -std=cxx is used.
>
> Here is a quick test I've made.
>
> #include <stdio.h>
>
> #define tt(X) _Generic((X), \
>                        int: "int", \
>                        default: "other")
>
> int
> main() {
>   printf("__STDC_VERSION__ %d\n", __STDC_VERSION__);
>   printf("_Alignof(double) %d\n", _Alignof(double));
>   printf("_Generic(int)    %s\n", tt(42));
> }
>
> address@hidden ~]$ gcc -std=c11 foo.c -o foo && ./foo
> __STDC_VERSION__ 201112
> _Alignof(double) 8
> _Generic(int)    int
> address@hidden ~]$ gcc -std=c99 foo.c -o foo && ./foo
> __STDC_VERSION__ 199901
> _Alignof(double) 8
> _Generic(int)    int
>
> You can see that with -std=c99 the two macros are available
>
> Only -pedantic flag makes gcc protest
>
> address@hidden ~]$ gcc -std=c99 -pedantic foo.c -o foo && ./foo
> foo.c: In function 'main':
> foo.c:10:35: warning: ISO C99 does not support '_Alignof' [-Wpedantic]
>    printf("_Alignof(double) %d\n", _Alignof(double));
>                                    ^~~~~~~~
> foo.c:3:15: warning: ISO C99 does not support '_Generic' [-Wpedantic]
>  #define tt(X) _Generic((X), \
>                ^~~~~~~~
>
>
> -----Original Message-----
> From: Tinycc-devel [mailto:address@hidden
> On Behalf Of Petr Skocík
> Sent: vendredi 11 janvier 2019 00:05
> To: address@hidden
> Subject: Re: [Tinycc-devel] Add max_align_t to stddef.h and C11
>
> Having __STDC_VERSION__ reflect the -std= command option is great.
> However, I think that disallowing _Generic and _Alignof at lower
> versions is unnecessarily pedantic (as in a behavior more suitable for
> compiler runs invoked with `-pedantic`). Unlike max_align_t, _Generic
> and _Alignof are reserved identifiers in any C version. They shouldn't
> ever need to be hidden. Hiding them can unnecessarily break some project
> builds that use tcc with  _Generic or _Alignof and without -std=c11.
>
> Petr S.
>
>
> On 1/10/19 11:47 PM, uso ewin wrote:
> > On Thu, Jan 10, 2019 at 2:47 PM Christian Jullien <address@hidden>
> wrote:
> >>
> >> Matthias,
> >>
> >>
> >> I'm happy you like my patch. I was waiting for comments before pushing
> this
> >> patch.
> >> As you said, no one protested (or care), so it is committed in mod.
> >>
> >> It let you add the logic for the C11.
> >>
> >> Christian
> >>
> >> -----Original Message-----
> >> From: Tinycc-devel
> [mailto:address@hidden
> >> On Behalf Of uso ewin
> >> Sent: jeudi 10 janvier 2019 11:13
> >> To: address@hidden
> >> Subject: Re: [Tinycc-devel] Add max_align_t to stddef.h and C11
> >>
> >> On Tue, Jan 8, 2019 at 6:02 PM Christian Jullien <address@hidden>
> wrote:
> >>>
> >>>> Maybe add a global variable
> >>>
> >>> Not global but a new member of TCCState, for example cversion
> >>>
> >>> If (s->cversion >= 201112) {
> >>>   /* Hello C11 */
> >>> }
> >>>
> >>> Diff becomes:
> >>>
> >>> address@hidden:~/new-tcc $ git diff
> >>> diff --git a/libtcc.c b/libtcc.c
> >>> index df7adab..7883734 100644
> >>> --- a/libtcc.c
> >>> +++ b/libtcc.c
> >>> @@ -1790,8 +1790,16 @@ reparse:
> >>>              s->static_link = 1;
> >>>              break;
> >>>          case TCC_OPTION_std:
> >>> -           /* silently ignore, a current purpose:
> >>> -              allow to use a tcc as a reference compiler for "make
> test"
> >> */
> >>> +            if (*optarg == '=') {
> >>> +                ++optarg;
> >>> +                if (strcmp(optarg, "c11") == 0) {
> >>> +                   tcc_undefine_symbol(s, "__STDC_VERSION__");
> >>> +                   tcc_define_symbol(s, "__STDC_VERSION__", "201112L");
> >>> +                   s->cversion = 201112;
> >>> +                }
> >>> +            }
> >>> +             /* silently ignore other values, a current purpose:
> >>> +                allow to use a tcc as a reference compiler for "make
> >> test"
> >>> */
> >>>              break;
> >>>          case TCC_OPTION_shared:
> >>>              x = TCC_OUTPUT_DLL;
> >>> diff --git a/tcc.c b/tcc.c
> >>> index f780389..2d4e1ea 100644
> >>> --- a/tcc.c
> >>> +++ b/tcc.c
> >>> @@ -33,6 +33,8 @@ static const char help[] =
> >>>      "  -o outfile  set output filename\n"
> >>>      "  -run        run compiled source\n"
> >>>      "  -fflag      set or reset (with 'no-' prefix) 'flag' (see tcc
> >> -hh)\n"
> >>> +    "  -std=c99    Conform to the ISO 1999 C standard (default).\n"
> >>> +    "  -std=c11    Conform to the ISO 2011 C standard.\n"
> >>>      "  -Wwarning   set or reset (with 'no-' prefix) 'warning' (see tcc
> >>> -hh)\n"
> >>>      "  -w          disable all warnings\n"
> >>>      "  -v -vv      show version, show search paths or loaded files\n"
> >>> diff --git a/tcc.h b/tcc.h
> >>> index cc85291..8416cc5 100644
> >>> --- a/tcc.h
> >>> +++ b/tcc.h
> >>> @@ -651,6 +651,7 @@ struct TCCState {
> >>>      int rdynamic; /* if true, all symbols are exported */
> >>>      int symbolic; /* if true, resolve symbols in the current module
> first
> >>> */
> >>>      int filetype; /* file type for compilation (NONE,C,ASM) */
> >>> +    int cversion; /* supported C ISO version, either 0 (199901),
> 201112,
> >>> ... */
> >>>
> >>>      char *tcc_lib_path; /* CONFIG_TCCDIR or -B option */
> >>>      char *soname; /* as specified on the command line (-soname) */
> >>>
> >>>
> >>>
> >>> _______________________________________________
> >>> Tinycc-devel mailing list
> >>> address@hidden
> >>> https://lists.nongnu.org/mailman/listinfo/tinycc-devel
> >>
> >> I like the version with cversion in tcc state.
> >>
> >> As no one protest, I guess you can push.
> >> Do you want to patch existing C11 code too ?
> >> if not I can do it, but I need this patch to be merge.
> >>
> >> Matthias,
> >>
> >> _______________________________________________
> >> Tinycc-devel mailing list
> >> address@hidden
> >> https://lists.nongnu.org/mailman/listinfo/tinycc-devel
> >>
> >>
> >> _______________________________________________
> >> Tinycc-devel mailing list
> >> address@hidden
> >> https://lists.nongnu.org/mailman/listinfo/tinycc-devel
> >
> > Hi,
> >
> > I've push the patch to allow _Alignof and _Generic only when -std=c11 is
> use.
> >
> > Matthias,
> >
> > _______________________________________________
> > Tinycc-devel mailing list
> > address@hidden
> > https://lists.nongnu.org/mailman/listinfo/tinycc-devel
> >
>
>
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>
>
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Ok, I've revert my change,
Sorry for the bug

matthias

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