* Problem report #90
@ 2006-07-17 18:01 Dan Nicolaescu
2006-07-17 18:56 ` Andreas Schwab
0 siblings, 1 reply; 4+ messages in thread
From: Dan Nicolaescu @ 2006-07-17 18:01 UTC (permalink / raw)
CID: 90
Checker: UNINIT (help)
File: base/src/emacs/src/eval.c
Function: Ffuncall
Description: Using uninitialized value "val"
Event var_decl: Declared variable "val" without initializer
Also see events: [uninit_use]
2839 Lisp_Object val;
2840 struct backtrace backtrace;
2841 register Lisp_Object *internal_args;
2842 register int i;
2843
2844 QUIT;
2845 if ((consing_since_gc > gc_cons_threshold
2846 && consing_since_gc > gc_relative_threshold)
2847 ||
2848 (!NILP (Vmemory_full) && consing_since_gc > memory_full_cons_threshold))
2849 Fgarbage_collect ();
2850
2851 if (++lisp_eval_depth > max_lisp_eval_depth)
2852 {
2853 if (max_lisp_eval_depth < 100)
2854 max_lisp_eval_depth = 100;
2855 if (lisp_eval_depth > max_lisp_eval_depth)
2856 error ("Lisp nesting exceeds `max-lisp-eval-depth'");
2857 }
2858
2859 backtrace.next = backtrace_list;
2860 backtrace_list = &backtrace;
2861 backtrace.function = &args[0];
2862 backtrace.args = &args[1];
2863 backtrace.nargs = nargs - 1;
2864 backtrace.evalargs = 0;
2865 backtrace.debug_on_exit = 0;
2866
2867 if (debug_on_next_call)
2868 do_debug_on_call (Qlambda);
2869
2870 CHECK_CONS_LIST ();
2871
2872 original_fun = args[0];
2873
2874 retry:
2875
2876 /* Optimize for no indirection. */
2877 fun = original_fun;
At conditional (9): "fun & 7 == 1" taking true path
At conditional (10): "fun != Qunbound" taking true path
At conditional (11): "(fun = ((0), (fun & -8))->function), (fun & 7 == 1)" taking true path
2878 if (SYMBOLP (fun) && !EQ (fun, Qunbound)
2879 && (fun = XSYMBOL (fun)->function, SYMBOLP (fun)))
2880 fun = indirect_function (fun);
2881
At conditional (1): "((0), (fun & -8))->size & 1073758208 == 1073758208" taking false path
At conditional (12): "fun & 7 == 4" taking true path
At conditional (13): "((0), (fun & -8))->size & 1073758208 == 1073758208" taking false path
2882 if (SUBRP (fun))
2883 {
2884 if (numargs < XSUBR (fun)->min_args
2885 || (XSUBR (fun)->max_args >= 0 && XSUBR (fun)->max_args < numargs))
2886 {
2887 XSETFASTINT (lisp_numargs, numargs);
2888 Fsignal (Qwrong_number_of_arguments, list2 (original_fun, lisp_numargs));
2889 }
2890
2891 if (XSUBR (fun)->max_args == UNEVALLED)
2892 Fsignal (Qinvalid_function, Fcons (original_fun, Qnil));
2893
2894 if (XSUBR (fun)->max_args == MANY)
2895 {
2896 val = (*XSUBR (fun)->function) (numargs, args + 1);
2897 goto done;
2898 }
2899
2900 if (XSUBR (fun)->max_args > numargs)
2901 {
2902 internal_args = (Lisp_Object *) alloca (XSUBR (fun)->max_args * sizeof (Lisp_Object));
2903 bcopy (args + 1, internal_args, numargs * sizeof (Lisp_Object));
2904 for (i = numargs; i < XSUBR (fun)->max_args; i++)
2905 internal_args[i] = Qnil;
2906 }
2907 else
2908 internal_args = args + 1;
2909 switch (XSUBR (fun)->max_args)
2910 {
2911 case 0:
2912 val = (*XSUBR (fun)->function) ();
2913 goto done;
2914 case 1:
2915 val = (*XSUBR (fun)->function) (internal_args[0]);
2916 goto done;
2917 case 2:
2918 val = (*XSUBR (fun)->function) (internal_args[0], internal_args[1]);
2919 goto done;
2920 case 3:
2921 val = (*XSUBR (fun)->function) (internal_args[0], internal_args[1],
2922 internal_args[2]);
2923 goto done;
2924 case 4:
2925 val = (*XSUBR (fun)->function) (internal_args[0], internal_args[1],
2926 internal_args[2], internal_args[3]);
2927 goto done;
2928 case 5:
2929 val = (*XSUBR (fun)->function) (internal_args[0], internal_args[1],
2930 internal_args[2], internal_args[3],
2931 internal_args[4]);
2932 goto done;
2933 case 6:
2934 val = (*XSUBR (fun)->function) (internal_args[0], internal_args[1],
2935 internal_args[2], internal_args[3],
2936 internal_args[4], internal_args[5]);
2937 goto done;
2938 case 7:
2939 val = (*XSUBR (fun)->function) (internal_args[0], internal_args[1],
2940 internal_args[2], internal_args[3],
2941 internal_args[4], internal_args[5],
2942 internal_args[6]);
2943 goto done;
2944
2945 case 8:
2946 val = (*XSUBR (fun)->function) (internal_args[0], internal_args[1],
2947 internal_args[2], internal_args[3],
2948 internal_args[4], internal_args[5],
2949 internal_args[6], internal_args[7]);
2950 goto done;
2951
2952 default:
2953
2954 /* If a subr takes more than 8 arguments without using MANY
2955 or UNEVALLED, we need to extend this function to support it.
2956 Until this is done, there is no way to call the function. */
2957 abort ();
2958 }
2959 }
At conditional (2): "fun & 7 == 4" taking true path
At conditional (3): "((0), (fun & -8))->size & 1073743872 == 1073743872" taking false path
At conditional (14): "fun & 7 == 4" taking true path
At conditional (15): "((0), (fun & -8))->size & 1073743872 == 1073743872" taking false path
2960 if (COMPILEDP (fun))
2961 val = funcall_lambda (fun, numargs, args + 1);
2962 else
2963 {
At conditional (4): "fun == Qunbound" taking true path
At conditional (16): "fun == Qunbound" taking true path
2964 if (EQ (fun, Qunbound))
2965 Fsignal (Qvoid_function, Fcons (original_fun, Qnil));
At conditional (5): "fun & 7 != 5" taking true path
At conditional (17): "fun & 7 != 5" taking true path
2966 if (!CONSP (fun))
2967 Fsignal (Qinvalid_function, Fcons (original_fun, Qnil));
2968 funcar = Fcar (fun);
At conditional (6): "funcar & 7 != 1" taking true path
At conditional (18): "funcar & 7 != 1" taking true path
2969 if (!SYMBOLP (funcar))
2970 Fsignal (Qinvalid_function, Fcons (original_fun, Qnil));
At conditional (7): "funcar == Qlambda" taking false path
At conditional (19): "funcar == Qlambda" taking false path
2971 if (EQ (funcar, Qlambda))
2972 val = funcall_lambda (fun, numargs, args + 1);
At conditional (8): "funcar == Qautoload" taking true path
At conditional (20): "funcar == Qautoload" taking false path
2973 else if (EQ (funcar, Qautoload))
2974 {
2975 do_autoload (fun, original_fun);
2976 CHECK_CONS_LIST ();
2977 goto retry;
2978 }
2979 else
2980 Fsignal (Qinvalid_function, Fcons (original_fun, Qnil));
2981 }
2982 done:
2983 CHECK_CONS_LIST ();
2984 lisp_eval_depth--;
At conditional (21): "(backtrace).debug_on_exit != 0" taking false path
2985 if (backtrace.debug_on_exit)
2986 val = call_debugger (Fcons (Qexit, Fcons (val, Qnil)));
2987 backtrace_list = backtrace.next;
Event uninit_use: Using uninitialized value "val"
Also see events: [var_decl]
2988 return val;
2989 }
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: Problem report #90
2006-07-17 18:01 Problem report #90 Dan Nicolaescu
@ 2006-07-17 18:56 ` Andreas Schwab
2006-07-19 4:09 ` Miles Bader
0 siblings, 1 reply; 4+ messages in thread
From: Andreas Schwab @ 2006-07-17 18:56 UTC (permalink / raw)
Dan Nicolaescu <dann@ics.uci.edu> writes:
> 2960 if (COMPILEDP (fun))
> 2961 val = funcall_lambda (fun, numargs, args + 1);
> 2962 else
> 2963 {
>
> At conditional (4): "fun == Qunbound" taking true path
> At conditional (16): "fun == Qunbound" taking true path
>
> 2964 if (EQ (fun, Qunbound))
> 2965 Fsignal (Qvoid_function, Fcons (original_fun, Qnil));
Since Fsignal does not return the true path here and similar paths below
are uninteresting. With this premise there is always an assignment to
val.
Andreas.
--
Andreas Schwab, SuSE Labs, schwab@suse.de
SuSE Linux Products GmbH, Maxfeldstraße 5, 90409 Nürnberg, Germany
PGP key fingerprint = 58CA 54C7 6D53 942B 1756 01D3 44D5 214B 8276 4ED5
"And now for something completely different."
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: Problem report #90
2006-07-17 18:56 ` Andreas Schwab
@ 2006-07-19 4:09 ` Miles Bader
2006-07-19 4:42 ` Stefan Monnier
0 siblings, 1 reply; 4+ messages in thread
From: Miles Bader @ 2006-07-19 4:09 UTC (permalink / raw)
Cc: emacs-devel
Andreas Schwab <schwab@suse.de> writes:
> Since Fsignal does not return the true path here and similar paths below
> are uninteresting. With this premise there is always an assignment to
> val.
I guess this has probably been discussed before, but why aren't
functions like Fsignal annotated as never returning?
[At least when using gcc.]
-Miles
--
Run away! Run away!
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: Problem report #90
2006-07-19 4:09 ` Miles Bader
@ 2006-07-19 4:42 ` Stefan Monnier
0 siblings, 0 replies; 4+ messages in thread
From: Stefan Monnier @ 2006-07-19 4:42 UTC (permalink / raw)
Cc: Andreas Schwab, emacs-devel
>> Since Fsignal does not return the true path here and similar paths below
>> are uninteresting. With this premise there is always an assignment
>> to val.
> I guess this has probably been discussed before, but why aren't
> functions like Fsignal annotated as never returning?
See Kim's recent patch that introduce xsignal.
The problem which that patch solves is that Fsignal sometimes can return (if
signalling a `quit'), so it's incorrect to annotate it as never returning.
Stefan
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2006-07-19 4:42 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz follow: Atom feed
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2006-07-17 18:01 Problem report #90 Dan Nicolaescu
2006-07-17 18:56 ` Andreas Schwab
2006-07-19 4:09 ` Miles Bader
2006-07-19 4:42 ` Stefan Monnier
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