hist_fn_call
static u64 hist_fn_call(struct hist_field *hist_field,
expr->constant = hist_fn_call(expr, NULL, NULL, NULL, NULL);
u64 val = hist_fn_call(operand, elt, buffer, rbe, event);
u64 val = hist_fn_call(operand, elt, buffer, rbe, event);
var_val = hist_fn_call(val, elt, buffer, rbe, rec);
u64 val1 = hist_fn_call(operand1, elt, buffer, rbe, event);
u64 val2 = hist_fn_call(operand2, elt, buffer, rbe, event);
u64 val1 = hist_fn_call(operand1, elt, buffer, rbe, event);
u64 val2 = hist_fn_call(operand2, elt, buffer, rbe, event);
u64 val1 = hist_fn_call(operand1, elt, buffer, rbe, event);
u64 val2 = hist_fn_call(operand2, elt, buffer, rbe, event);
u64 val1 = hist_fn_call(operand1, elt, buffer, rbe, event);
u64 val1 = hist_fn_call(operand1, elt, buffer, rbe, event);
u64 val1 = hist_fn_call(operand1, elt, buffer, rbe, event);
u64 val1 = hist_fn_call(operand1, elt, buffer, rbe, event);
u64 val2 = hist_fn_call(operand2, elt, buffer, rbe, event);
s64 sval = (s64)hist_fn_call(operand, elt, buffer, rbe, event);
hist_val = hist_fn_call(hist_field, elt, buffer, rbe, rec);
hist_val = hist_fn_call(hist_field, elt, buffer, rbe, rec);
field_contents = hist_fn_call(key_field, elt, buffer, rbe, rec);
field_contents = hist_fn_call(key_field, elt, buffer, rbe, rec);