Re: [Tinycc-devel] Attributes position on structs/unions

[Vladimir Vissoultchev]

Btw, current -dD option is not documented in tcc-doc.texi and I'm not sure
how to proceed for the new -dM one.

>From here https://gcc.gnu.org/onlinedocs/gcc/Preprocessor-Options.html on
-dCHARS

> -dCHARS
>   CHARS is a sequence of one or more of the following characters, and must
not
>   be preceded by a space. Other characters are interpreted by the compiler

>   proper, or reserved for future versions of GCC, and so are silently
ignored.
>   If you specify characters whose behavior conflicts, the result is
undefined.
>
>   'M'
>       Instead of the normal output, generate a list of '#define'
directives 
>       for all the macros defined during the execution of the preprocessor,

>       including predefined macros. This gives you a way of finding out
what is
>       predefined in your version of the preprocessor. Assuming you have no

>       file foo.h, the command
>
>               touch foo.h; cpp -dM foo.h
>
>       will show all the predefined macros.
>
>       If you use -dM without the -E option, -dM is interpreted as a
synonym 
>       for -fdump-rtl-mach. See Developer Options. 
>
>   'D'
>       Like 'M' except in two respects: it does not include the predefined 
>       macros, and it outputs both the '#define' directives and the result
of 
>       preprocessing. Both kinds of output go to the standard output file.

tcc does not silently ignore anything different that `M` and `D` but
terminates with an error. `D` seems to include
predefines macros too. There is no -dM without -E too.

cheers,
</wqw>