[Bug d/105544] gdc fails to compile d source from stdin
fabian@ritter-vogt.de
gcc-bugzilla@gcc.gnu.org
Thu May 12 09:44:56 GMT 2022
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105544
--- Comment #9 from Fabian Vogt <fabian@ritter-vogt.de> ---
(In reply to ibuclaw from comment #8)
> (In reply to Fabian Vogt from comment #6)
> > I had a quick debugging session: The DMD lexer code doesn't really care
> > about the size of the buffer and instead runs until it encounters either a 0
> > or 0x1A byte. The stdin read loop in d_parse_file doesn't explicitly
> > 0-terminate the buffer, which means that it works randomly...
> >
>
> OK, so the suggestion would be to zero the padding at the end of the input
> buffer then.
>
> --- a/gcc/d/d-lang.cc
> +++ b/gcc/d/d-lang.cc
> @@ -1072,6 +1072,10 @@ d_parse_file (void)
> global.params.doHdrGeneration);
> modules.push (m);
>
> + /* Zero the padding past the end of the buffer so the D lexer has a
> + sentinel. The lexer only reads up to 4 bytes at a time. */
> + memset (buffer + len, '\0', 16);
> +
> /* Overwrite the source file for the module, the one created by
> Module::create would have a forced a `.d' suffix. */
> m->src.length = len;
Yep, that should work. Though I wonder why 16B of padding and not just a single
byte for the 0. FWICT the lexer reads a single byte at a time only (utf8_t is
an unsigned char), so it should stop at the first 0.
The comment above explaining the padding mentions a "final '\n'" which should
probably be adjusted with the change to \0.
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