base-stats,mem: Fix empty Stats::Info names

Sub-groups should not contain empty names. To make sure
that is the case, generate tokens even if the string is
empty.

Before the name 'group1..group2' would generate 2 tokens:
'group1' and 'group2'. As such, validateStatName would
not be able to detect it was an invalid name. With this
change three tokens will be generated: 'group1', '',
and 'group2'. The empty string will then trigger the
item->empty() check, which will successfully inform that
such stat name is not valid.

SLICC was breaking this rule with one of its stats by
creating a sub-group (inTransLatHist) whose parent had
an empty name, so it has been fixed.

Change-Id: Ica5ca684911374d59a0a809636594d048d755deb
Signed-off-by: Daniel R. Carvalho <odanrc@yahoo.com.br>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/43590
Reviewed-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Maintainer: Giacomo Travaglini <giacomo.travaglini@arm.com>
Tested-by: kokoro <noreply+kokoro@google.com>

src/base/stats/info.cc

@@ -86,7 +86,7 @@ validateStatName(const std::string &name)
         return false;
 
     std::vector<std::string> vec;
-    tokenize(vec, name, '.');
+    tokenize(vec, name, '.', false);
     std::vector<std::string>::const_iterator item = vec.begin();
     while (item != vec.end()) {
         if (item->empty())

src/mem/slicc/symbols/StateMachine.py

@@ -870,7 +870,7 @@ $c_ident::regStats()
 
     for (${ident}_Event event = ${ident}_Event_FIRST;
                  event < ${ident}_Event_NUM; ++event) {
-        std::string stat_name = ".inTransLatHist." +
+        std::string stat_name = "inTransLatHist." +
                                 ${ident}_Event_to_string(event);
         statistics::Scalar* r = new statistics::Scalar(&stats,
                                              (stat_name + ".total").c_str());