Hi,
Please forgive me but I am just learning how to debug in this
environment.
Info on Bug 7924, as far as I understand the comment, if someone knew
how calling identical(call1,call2) actually helped set NAMED it might
lead them to a solution.
Here is my attempt to track down when how this happens.
Okay from examining compute_identical in main/identical.c it is clear
that it does not change any of the NAMED values (this is also shown
by single stepping through the entire routine.
Therefore the "fix" caused by invoking "identical" must have happened
either on the way there or on the way back.
Here is the backtrace from the call to identical for the problem case
(gdb) bt
#0 compute_identical (x=0x9a0130, y=0x99d0f0) at ../../../r-devel/r-
devel/R/src/main/identical.c:53
#1 0x00002aaaaab7fede in do_identical (x=0x9a0130, y=0x99d0f0)
at ../../../r-devel/r-devel/R/src/main/identical.c:38
#2 0x00002aaaaab95650 in do_internal (call=Variable "call" is not
available.
) at ../../../r-devel/r-devel/R/src/main/names.c:1093
#3 0x00002aaaaab6785b in Rf_eval (e=0x92ea98, rho=0x999750)
at ../../../r-devel/r-devel/R/src/main/eval.c:424
#4 0x00002aaaaab697c6 in Rf_applyClosure (call=0x99d2b0,
op=0x92d678, arglist=0x999638, rho=0x547858, suppliedenv=0x547890)
at ../../../r-devel/r-devel/R/src/main/eval.c:614
#5 0x00002aaaaab676f8 in Rf_eval (e=0x99d2b0, rho=0x547858)
at ../../../r-devel/r-devel/R/src/main/eval.c:455
#6 0x00002aaaaab8639e in Rf_ReplIteration (rho=0x547858,
savestack=0, browselevel=0, state=0x7fffffd59a70) at ../../../r-devel/
r-devel/R/src/main/main.c:254
#7 0x00002aaaaab86540 in R_ReplConsole (rho=0x547858, savestack=0,
browselevel=0) at ../../../r-devel/r-devel/R/src/main/main.c:302
#8 0x00002aaaaab86860 in run_Rmainloop () at ../../../r-devel/r-
devel/R/src/main/main.c:915
#9 0x000000000040081d in main (ac=Variable "ac" is not available.
) at ../../../r-devel/r-devel/R/src/main/Rmain.c:33
Now grepping through all of the files in main for the macro SET_NAMED
many of them appear in eval.c
Specifically, some appear in R_eval which is in the backtrace to
compute_identical.
So I set a breakpoint for Rf_eval and for every line in that routine
that invokes SET_NAMED.
Here is a result of the gdb trace (see my comments sprinkled
throughout) as the problem case is entered.
Please forgive its length
> call1<- Quote(f(arg[[1]], arg[[1]], arg[[1]]))
Breakpoint 3, Rf_eval (e=0x9a0328, rho=0x547858) at ../../../r-devel/
r-devel/R/src/main/eval.c:307
307 {
(gdb) c
Continuing.
Breakpoint 3, Rf_eval (e=0x9a0280, rho=0x547858) at ../../../r-devel/
r-devel/R/src/main/eval.c:307
307 {
(gdb) c
Continuing.
Breakpoint 3, Rf_eval (e=0x775ff8, rho=0x547858) at ../../../r-devel/
r-devel/R/src/main/eval.c:307
307 {
(gdb) c
Continuing.
So we see none of the SET_NAMED breakpoints (in Rf_eval) being set
when call1 is first defined which makes sense (at least with my
limited understanding it does).
Now here we define call2
> call2 <- Quote(f(arg[[1]]))[c(1,2,2,2)]
Breakpoint 3, Rf_eval (e=0x99ddb8, rho=0x547858) at ../../../r-devel/
r-devel/R/src/main/eval.c:307
Breakpoint 3, Rf_eval (e=0x99dd10, rho=0x547858) at ../../../r-devel/
r-devel/R/src/main/eval.c:307
Breakpoint 3, Rf_eval (e=0x9a06a8, rho=0x547858) at ../../../r-devel/
r-devel/R/src/main/eval.c:307
Breakpoint 3, Rf_eval (e=0x775ff8, rho=0x547858) at ../../../r-devel/
r-devel/R/src/main/eval.c:307
Breakpoint 3, Rf_eval (e=0x99dbc0, rho=0x547858) at ../../../r-devel/
r-devel/R/src/main/eval.c:307
Breakpoint 3, Rf_eval (e=0xf7f118, rho=0x547858) at ../../../r-devel/
r-devel/R/src/main/eval.c:307
Below in the definition of call2 we see SET_NAMED being set to 2
which I think if I understand things makes sense.
Breakpoint 4, Rf_eval (e=0xf7f118, rho=0x547858) at ../../../r-devel/
r-devel/R/src/main/eval.c:362
362 if (NAMED(tmp) != 2) SET_NAMED(tmp, 2);
(gdb) c
Continuing.
358 /* Make sure constants in expressions are NAMED
before being
359 used as values. Setting NAMED to 2 makes sure
weird calls
360 to assignment functions won't modify constants in
361 expressions. */
362 if (NAMED(tmp) != 2) SET_NAMED(tmp, 2);
Breakpoint 3, Rf_eval (e=0xf7f148, rho=0x547858) at ../../../r-devel/
r-devel/R/src/main/eval.c:307
And again
Breakpoint 4, Rf_eval (e=0xf7f148, rho=0x547858) at ../../../r-devel/
r-devel/R/src/main/eval.c:362
362 if (NAMED(tmp) != 2) SET_NAMED(tmp, 2);
Breakpoint 3, Rf_eval (e=0xf7f1d8, rho=0x547858) at ../../../r-devel/
r-devel/R/src/main/eval.c:307
And Again
Breakpoint 4, Rf_eval (e=0xf7f1d8, rho=0x547858) at ../../../r-devel/
r-devel/R/src/main/eval.c:362
362 if (NAMED(tmp) != 2) SET_NAMED(tmp, 2);
(gdb) c
Continuing.
Breakpoint 3, Rf_eval (e=0xf7f208, rho=0x547858) at ../../../r-devel/
r-devel/R/src/main/eval.c:307
And again but always via line 362
Breakpoint 4, Rf_eval (e=0xf7f208, rho=0x547858) at ../../../r-devel/
r-devel/R/src/main/eval.c:362
362 if (NAMED(tmp) != 2) SET_NAMED(tmp, 2);
(gdb) c
Continuing.
Now we run the identical(call1,call2) statement
> identical(call1,call2)
Breakpoint 3, Rf_eval (e=0x99d2b0, rho=0x547858) at ../../../r-devel/
r-devel/R/src/main/eval.c:307
Breakpoint 3, Rf_eval (e=0x7509b0, rho=0x547858) at ../../../r-devel/
r-devel/R/src/main/eval.c:307
Breakpoint 3, Rf_eval (e=0x92ea98, rho=0x999750) at ../../../r-devel/
r-devel/R/src/main/eval.c:307
Breakpoint 3, Rf_eval (e=0x56ca30, rho=0x999750) at ../../../r-devel/
r-devel/R/src/main/eval.c:307
Breakpoint 3, Rf_eval (e=0x99d320, rho=0x999750) at ../../../r-devel/
r-devel/R/src/main/eval.c:307
Breakpoint 3, Rf_eval (e=0x9ecb28, rho=0x547858) at ../../../r-devel/
r-devel/R/src/main/eval.c:307
And finally we see SET_NAMED being set in a different place in the
code then in the original definition.
So for some reason when call2 is first defined for PROMSXP objects,
the SET_NAMED field is not properly set?
Breakpoint 5, Rf_eval (e=0x56ca30, rho=0x999750) at ../../../r-devel/
r-devel/R/src/main/eval.c:389
389 SET_NAMED(tmp, 2);
(gdb) list
384 else error(_("argument is missing, with no
default"));
385 }
386 else if (TYPEOF(tmp) == PROMSXP) {
387 PROTECT(tmp);
388 tmp = eval(tmp, rho);
389 SET_NAMED(tmp, 2);
390 UNPROTECT(1);
391 }
392 else if (!isNull(tmp) && NAMED(tmp) < 1)
393 SET_NAMED(tmp, 1);
(gdb) c
Continuing.
Breakpoint 3, Rf_eval (e=0x92d5d0, rho=0x999750) at ../../../r-devel/
r-devel/R/src/main/eval.c:307
Breakpoint 3, Rf_eval (e=0x999670, rho=0x999750) at ../../../r-devel/
r-devel/R/src/main/eval.c:307
Breakpoint 3, Rf_eval (e=0x9eb938, rho=0x547858) at ../../../r-devel/
r-devel/R/src/main/eval.c:307
It happens here again
Breakpoint 5, Rf_eval (e=0x92d5d0, rho=0x999750) at ../../../r-devel/
r-devel/R/src/main/eval.c:389
389 SET_NAMED(tmp, 2);
(gdb) list
384 else error(_("argument is missing, with no
default"));
385 }
386 else if (TYPEOF(tmp) == PROMSXP) {
387 PROTECT(tmp);
388 tmp = eval(tmp, rho);
389 SET_NAMED(tmp, 2);
390 UNPROTECT(1);
391 }
392 else if (!isNull(tmp) && NAMED(tmp) < 1)
393 SET_NAMED(tmp, 1);
(gdb) c
Continuing.
And then finally compute_identical is reached.
Breakpoint 1, compute_identical (x=0x9a0130, y=0x99d0f0) at ../../../
r-devel/r-devel/R/src/main/identical.c:53
53 {
$150 = {sxpinfo = {type = 6, obj = 0, named = 2, gp = 0, mark = 0,
debug = 0, trace = 0, fin = 0, gcgen = 0, gccls = 0}, attrib =
0x508818, gengc_next_node = 0x9a0168,
gengc_prev_node = 0x9a00f8, u = {primsxp = {offset = 10663048},
symsxp = {pname = 0xa2b488, value = 0x9a15b0, internal = 0x508818},
listsxp = {carval = 0xa2b488,
cdrval = 0x9a15b0, tagval = 0x508818}, envsxp = {frame =
0xa2b488, enclos = 0x9a15b0, hashtab = 0x508818}, closxp = {formals =
0xa2b488, body = 0x9a15b0,
env = 0x508818}, promsxp = {value = 0xa2b488, expr = 0x9a15b0,
env = 0x508818}}}
$151 = {sxpinfo = {type = 6, obj = 0, named = 2, gp = 0, mark = 0,
debug = 0, trace = 0, fin = 0, gcgen = 0, gccls = 0}, attrib =
0x508818, gengc_next_node = 0x99d128,
gengc_prev_node = 0x99d0b8, u = {primsxp = {offset = 10663048},
symsxp = {pname = 0xa2b488, value = 0x99d0b8, internal = 0x508818},
listsxp = {carval = 0xa2b488,
cdrval = 0x99d0b8, tagval = 0x508818}, envsxp = {frame =
0xa2b488, enclos = 0x99d0b8, hashtab = 0x508818}, closxp = {formals =
0xa2b488, body = 0x99d0b8,
env = 0x508818}, promsxp = {value = 0xa2b488, expr = 0x99d0b8,
env = 0x508818}}}
I then continued and showed that none of the breakpoints for
SET_NAMED (at least in Rf_eval) were invoked on the way out.
So one possible hypothesis is that Rf_eval as called when doing
indentical(call1,call2) actually fixes up NAMED values on the way to
that routine compute_identical and that is why it helps.
I still don't know enough about how R works but reading up in include/
Rinternals.h makes me think of C++ code written in C (like Xorg's
X11 code). I really like the code base and its is clean and well
documented and organized. Congrats to the developers on that by the
way!
Hope this helps. If not, I will begin to track down what is going on
during the define of call2 that may not be possibly setting NAMED
values properly for PROMSXP sub objects?
Kevin
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