[Bug preprocessor/14438] [3.5, needs investigation] -E of #pragma has negative line number

["aoliva at redhat dot com" <gcc-bugzilla at gcc dot gnu dot org>]

------- Additional Comments From aoliva at redhat dot com  2004-03-24 04:31 -------
Subject: Re: preprocessor/14438

The reason why the patch had introduced a regression was that
pfile->cur_token pointed to uninitialized memory, one past the last
initialized token.  _cpp_lex_direct() doesn't skip to the next line
because we're processing a directive, so it just sets result->type to
CPP_EOF, along with its correct location, after incrementing
pfile->cur_token past result, without any form of initialization to
this value.  In fact, I'm a bit concerned as to what might happen if
we were to call _cpp_lex_direct() an unlimited number of times while
processing a directive; I don't see anything that would prevent
cur_token from running past the memory area reserved for it.

I suppose one way to fix this issue would be to decrement cur_token
again when returning in the CPP_EOF case, such that we'd return the
same EOF token over and over; another would be to just refrain from
dereferencing cur_token after reading an EOF token, but how would we
tell?  And, more importantly, why would we want to?  Clearly we don't
need it in the case I thought we did when I added the code I just
removed; I don't think we need it elsewhere.

Is this analysis enough for us to close this bug report now?



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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14438