[Tinycc-devel] Fixing nonconformant scoping

[Petr Skocik]

    Hi. I noticed tinycc doesn't correctly scope enumerators constants
    defined in the argument parentheses to switches/whiles/do-whiles and
    ifs.
    
    Example below:
> #include <stdio.h>
>       enum{ in = 0};
>       #define myassert(X) do{ if(!X) printf("%d: assertion failed\n",
>       __LINE__); }while(0)
>       int main(){
>           {
>               myassert(!in);
>               if(sizeof(enum{in=1})) myassert(in);
>               myassert(!in); //OOPS
>           }
>           {
>               myassert(!in);
>               switch(sizeof(enum{in=1})) { default: myassert(in); }
>               myassert(!in); //OOPS
>           }
>           {
>               myassert(!in);
>               while(sizeof(enum{in=1})) { myassert(in); break; }
>               myassert(!in); //OOPS
>           }
>           {
>               myassert(!in);
>               do{ myassert(!in);}while(0*sizeof(enum{in=1}));
>               myassert(!in); //OOPS
>           }
>       
>           {
>               myassert(!in);
>               for(sizeof(enum{in=1});;){ myassert(in); break; }
>               myassert(!in); //OK
>           }
>           {
>               myassert(!in);
>               for(;;sizeof(enum{in=1})){ myassert(in); break; }
>               myassert(!in); //OK
>           }
>           {
>               myassert(!in);
>               for(;sizeof(enum{in=1});){ myassert(in); break; }
>               myassert(!in); //OK
>           }
>       
>       }
>       
>     
    Fors are done correctly.
    
    Because I'm weird and actually make use of these scoping rules, I
    would welcome tinycc doing this as prescribed.
    
    Surrounding the code parsing these statements with
    new_scope(&o); and prev_scope(&o,0); appears to fix the
    problem without introducing test breakage except when it's done for
    ifs -- then I get breakage in tests2.122 -- vla_reuse.
    
    I've pushed the fixes for the rest for now (lucky for me, I don't
    actually need this weird feature with ifs -- just
    whiles/do-whiles/switches and fors).
    
    If I've done something stupid or if anybody knows how to make it
    work for ifs too without breaking the vla test, then please let me
    know.
    
    Cheers,
    Petr Skocik