On Thu, Apr 30, 2015 at 8:03 PM, grischka <[email protected]> wrote:
> Pip Cet wrote:
>>
>> Does this fix it for you? Even if it doesn't, this should indicate
>> where the code is that goes wrong...
>
>
> Yep, just funny how long it did NOT go wrong...
Well, it happens exclusively when a macro expands recursively to
another macro and we hit EOB at the same time. I'm about to commit
some changes that make tcc read files one character at a time (when
debugging is enabled, of course), which might help find such bugs in
future...
>> ch = tcc_peekc_slow(file);
>
> as in ch = handle_eob();
I think peekc_slow indicates more precisely what we're doing—reading
the next character, whether or not we're at EOB. handle_eob() sounds
like we're definitely at EOB, which we might not be. However, feel
free to change this if you disagree.
>
> One more, anyone ?
>
> #define t(x,y,z) x ## y ## z
>
> int main(int argc, char **argv)
> {
> return t(1,,) + t(,2,) + t(,,3);
>
> }
Does C99 allow concatenating two empty tokens?
#define t(x,y) x ## y
void main(int argc, char **argv)
{
return t(,);
}
also doesn't do what it probably should.
Here's a patch that makes things work by brute force, and it doesn't
appear to break any of the tests. However, it does make:
#define t(x,y) x ## y
#define A(x,y...) f(x,##y)
A(a,t(,))
produce f(, ), with the extra comma. That's not really compatible
with A(a,) -> f(x), though GCC has stopped handling this case
specially (see http://gcc.gnu.org/onlinedocs/cpp/Variadic-Macros.html),
so maybe we should as well... (A(a) still works).
diff --git a/tccpp.c b/tccpp.c
index b44296d..86a3aeb 100644
--- a/tccpp.c
+++ b/tccpp.c
@@ -3039,13 +3039,15 @@ static inline int *macro_twosharps(const int *macro_str)
if (tok != TOK_PLCHLDR)
cstr_cat(&cstr, get_tok_str(tok, &tokc));
n = cstr.size;
- if (t != TOK_PLCHLDR || tok == TOK_PLCHLDR)
+ if (t != TOK_PLCHLDR)
cstr_cat(&cstr, get_tok_str(t, &cval));
cstr_ccat(&cstr, '\0');
tcc_open_bf(tcc_state, ":paste:", cstr.size);
memcpy(file->buffer, cstr.data, cstr.size);
for (;;) {
+ if (0 == *file->buf_ptr)
+ break;
next_nomacro1();
if (0 == *file->buf_ptr)
break;
@@ -3058,7 +3060,8 @@ static inline int *macro_twosharps(const int *macro_str)
}
}
if (tok != TOK_NOSUBST) {
- tok_str_add2(¯o_str1, tok, &tokc);
+ if (tok != TOK_PLCHLDR)
+ tok_str_add2(¯o_str1, tok, &tokc);
tok = ' ';
start_of_nosubsts = -1;
}
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