[PATCH] D86508: [clang] implement+test remaining C90 __builtin_ functions

[Nick Desaulniers via Phabricator via cfe-commits]

nickdesaulniers added inline comments.


================
Comment at: clang/include/clang/Basic/Builtins.def:513
 BUILTIN(__builtin_printf, "icC*.", "Fp:0:")
+BUILTIN(__builtin_putchar, "ii", "F")
+BUILTIN(__builtin_puts, "icC*", "nF")
----------------
nickdesaulniers wrote:
> nickdesaulniers wrote:
> > nickdesaulniers wrote:
> > > rsmith wrote:
> > > > aaron.ballman wrote:
> > > > > Should we also add a builtin for `putc()` (I know that's often a macro, so I'm not certain if it applies)?
> > > > Yes, GCC has a `__builtin_putc`, so it'd make sense for us to support that too.
> > > Curious, `putc` isn't documented at https://gcc.gnu.org/onlinedocs/gcc/Other-Builtins.html, which is what I was using.  It looks like `putc` was a part of ANSI C, so I'm not sure what else might be missing from my implementation.  Let me see if I can find a more complete list of C90 functions to verify.
> > (retrieves copy of `The Standard C Library` from P. J. Plauger)
> Looks like I'm missing:
> 
> From stdlib.h:
> * `div`
> * `ldiv`
> * `bsearch`
> * `qsort`
> * `rand`
> * `srand`
> * `atof`
> * `atoi`
> * `atol`
> * `mblen`
> * `mbstowcs`
> * `mbtowc`
> * `wcstombs`
> * `wctomb`
> * `abort`
> * `atexit`
> * `getenv`
> * `system`
> 
> From string.h:
> * `strcoll`
> 
> From stdio.h:
> * `remove`
> * `rename`
> * `tmpfile`
> * `fclose`
> * `fflush`
> * `freopen`
> * `setvbuf`
> * `scanfwrite`
> * `fgetc`
> * `fgets`
> * `fputc`
> * `getc`
> * `getchar`
> * `gets`
> * `putc`
> * `ungetc`
> * `fgetpos`
> * `fseek`
> * `fsetpos`
> * `ftell`
> * `rewind`
> * `clearerr`
> * `feof`
> * `ferror`
> * `perror`
> 
> We look good on ctype.h and stdard.h.  Shall I very those against GCC and implement what's missing here?
(`abort` should not have been in the above list; it's in GCC's docs and we implement the builtin for it)

>From the above list, GCC has builtins for:
* fputc
* putc

We already support `abort.  Let me:
1. file a docs bug against GCC for those 2 undocumented builtins.
2. add implementations of them to this change.
3. add a test case for pr/47387 just to be safe.


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https://reviews.llvm.org/D86508