[Chicken-janitors] #1624: Flonum unboxing too agressive

[Chicken Trac]

#1624: Flonum unboxing too agressive
----------------------+------------------------------
 Reporter:  sjamaan   |                 Owner:
     Type:  defect    |                Status:  new
 Priority:  critical  |             Milestone:  5.2
Component:  compiler  |               Version:  5.1.0
 Keywords:  lfa2      |  Estimated difficulty:  hard
----------------------+------------------------------
 Found by Sven Hartrumpf. The following program will segfault:

 {{{
 (define (test-it)
   (let loop ((done #f))
     (if done
         '()
         (cons  (or (read) 0.0) (loop #t)))))

 (print (test-it))
 }}}

 When run with a {{{DEBUGBUILD}}} CHICKEN, you'll see it fails with a nice
 panic due to a low-level assertion error triggered by a
 {{{C_flonum_magnitude}}} call when you enter a fixnum:

 {{{
 [panic] Low-level type assertion
 C_blockp((C_word)C_VAL1(C__PREV_TMPST.n1))=#t failed at test.c:176 -
 execution terminated
 }}}

 Generated code failing:

 {{{
 /* k150 in loop in test-it in k131 in k128 in k125 */
 static void C_ccall f_152(C_word c,C_word *av){
 C_word tmp;
 C_word t0=av[0];
 C_word t1=av[1];
 C_word t2;
 C_word t3;
 C_word t4;
 double f0;
 C_word *a;
 C_check_for_interrupt;
 if(C_unlikely(!C_demand(C_calculate_demand(8,c,2)))){
 C_save_and_reclaim((void *)f_152,2,av);}
 a=C_alloc(8);
 f0=C_flonum_magnitude((C_truep(t1)?t1:lf[1])); /// <--- offending code
 t2=C_flonum(&a,f0);
 
t3=(*a=C_CLOSURE_TYPE|3,a[1]=(C_word)f_159,a[2]=((C_word*)t0)[2],a[3]=t2,tmp=(C_word)a,a+=4,tmp);
 C_trace(C_text("test.scm:5: loop"));
 t4=((C_word*)((C_word*)t0)[3])[1];
 f_141(t4,t3,C_SCHEME_TRUE);}
 }}}

 Most likely introduced by 79cf7427638eebf695f2be54731bb6bbf4d0fff2.

--
Ticket URL: <https://bugs.call-cc.org/ticket/1624>
CHICKEN Scheme <https://www.call-cc.org/>
CHICKEN Scheme is a compiler for the Scheme programming language.