The following will list the entire call stack at entry to a proc or method.
proc x {a} {
puts "Entered x, args $a"
set distanceToTop [info level]
for {set i 1} {$i < $distanceToTop} {incr i} {
set callerlevel [expr {$distanceToTop - $i}]
puts "CALLER $callerlevel: [info level $callerlevel]"
}
# ...
return
}