[Tinycc-devel] Hmmm...

[Rob Landley]

So, if the very first line of a file is an #include it apparently doesn't get 
processed.  This means that the #include <stdio.h> in hello.c never gets 
parsed unless you stick a blank line in front of it.  You can see this if you 
run "tcc -E hello.c".  (Why did nobody notice this before?  Doesn't it break 
stuff?)

This is due to this chunk of next_nomacro1():
>     case '#':
>         /* XXX: simplify */
>         PEEKC(c, p);
>         if ((next_tok_flags & TOK_FLAG_BOL) &&
>             (parse_flags & PARSE_FLAG_PREPROCESS)) {
>             file->buf_ptr = p;
>             preprocess(next_tok_flags & TOK_FLAG_BOF);
>             p = file->buf_ptr;
>             goto redo_no_start;
>         } else {
>             if (c == '#') {
>                 p++;
>                 tok = TOK_TWOSHARPS;
>             } else {
>                 if (parse_flags & PARSE_FLAG_ASM_COMMENTS) {
>                     p = parse_line_comment(p - 1);
>                     goto redo_no_start;
>                 } else {
>                     tok = '#';
>                 }
>             }
>         }

Every file starts out with next_tok_flags set to 0, so preprocess() never gets 
called on it.  This is set at the end of next_nomacro1() which gets called 
while processing the predefined #defines.

The fix is to initialize next_tok_flags in the file handling loop in main().  
I checked to make sure that #!/usr/bin/tcc -run as the first line still gets 
ignored properly (it does).

Rob
-- 
"One of my most productive days was throwing away 1000 lines of code."
  - Ken Thompson.