On Wed, Jan 26, 2011 at 10:29 PM, Stefan Behnel <stefan...@behnel.de> wrote: > Hi, > > ticket #654 describes a problem with the order in which function call > arguments are evaluated. I fixed it and it broke Sage.
Thanks for fixing this, I never got around to it last night. I'm wondering how many other similar situations may be lurking around. Of course we could store every sub-expression in temporary variables, but that would be less than ideal. > The problem was that in cases where some arguments are simple and others > are not, the non-simple arguments are stuffed into a temp before hand, thus > being evaluated before the other arguments. This can break side-effects of > simple arguments, which include C function calls. > > My fix was to put all arguments into temps if any of them are in temps > anyway. However, there is this code in Sage (wrapper_rr.pyx/.pxd): > > cdef class Wrapper_rr(Wrapper): > cdef int _n_args > cdef mpfr_t* _args > ... > > # offending line: > mpfr_init2(self._args[i], self.domain.prec()) > > The signature of mpfr_init2() is > > ctypedef __mpfr_struct* mpfr_t > void mpfr_init2 (mpfr_t x, mp_prec_t prec) > > Cython generates this code: > > mpfr_t __pyx_t_7; > ... > __pyx_t_7 = (((struct ...)__pyx_v_self)->_args[__pyx_v_i]); > ... > mpfr_init2(__pyx_t_7, __pyx_t_8); > > Looks reasonable at first sight. However, gcc complains about the temp > assignment: > > sage/ext/interpreters/wrapper_rr.c:2737: error: incompatible types in > assignment > > Any idea what might be going wrong here? mpfr_t is actually an __mpfr_struct[1]. (It's a clever hack to have stack-allocated, pass-by-reference semantics.) We only need to pull non-simple arguments into temp variables. - Robert _______________________________________________ Cython-dev mailing list Cython-dev@codespeak.net http://codespeak.net/mailman/listinfo/cython-dev
