Some renaming and comment updating.

diff --git a/re2c/src/codegen/emit_dfa.cc b/re2c/src/codegen/emit_dfa.cc
index b9e7e6c7c2b635fba9d8f8ef2ed253f2024d6263..4d895d3264ca52df7bce8de6f2db3f9be857176c 100644 (file)
--- a/re2c/src/codegen/emit_dfa.cc
+++ b/re2c/src/codegen/emit_dfa.cc
@@ -65,7 +65,7 @@ void emit_state (OutputFile & o, uint32_t ind, const State * s, bool used_label)
        }
 }
 
-void DFA::count_used_labels (std::set<uint32_t> & used, uint32_t prolog, uint32_t start, bool force_start) const
+void DFA::count_used_labels (std::set<uint32_t> & used, uint32_t start, uint32_t initial, bool force_start) const
 {
        // In '-f' mode, default state is always state 0
        if (fFlag)
@@ -74,7 +74,7 @@ void DFA::count_used_labels (std::set<uint32_t> & used, uint32_t prolog, uint32_
        }
        if (force_start)
        {
-               used.insert (prolog);
+               used.insert (start);
        }
        for (State * s = head; s; s = s->next)
        {
@@ -87,7 +87,7 @@ void DFA::count_used_labels (std::set<uint32_t> & used, uint32_t prolog, uint32_
        // must go last: it needs the set of used labels
        if (used.count (head->label))
        {
-               used.insert (start);
+               used.insert (initial);
        }
 }
 
@@ -97,21 +97,20 @@ void DFA::emit(Output & output, uint32_t& ind, const RegExpMap* specMap, const s
 
        bool bProlog = (!cFlag || !bWroteCondCheck);
 
-       // In -c mode, the prolog needs its own label separate from start_label.
-       // prolog_label is before the condition branch (GenCondGoto). It is
-       // equivalent to startLabelName.
-       // start_label corresponds to current condition.
-       // NOTE: prolog_label must be yy0 because of the !getstate:re2c handling
-       // in scanner.re
-       uint32_t prolog_label = next_label;
+       // start_label points to the beginning of current re2c block
+       // (prior to condition dispatch in '-c' mode)
+       // it can forced by configuration 're2c:startlabel = <integer>;'
+       uint32_t start_label = next_label;
        if (bProlog && cFlag)
        {
                next_label++;
        }
 
-       uint32_t start_label = next_label++;
+       // initial_label points to the beginning of DFA
+       // in '-c' mode this is NOT equal to start_label
+       uint32_t initial_label = next_label++;
 
-       head->action.set_initial (start_label, bSaveOnHead);
+       head->action.set_initial (initial_label, bSaveOnHead);
 
 
        State *s;
@@ -122,7 +121,7 @@ void DFA::emit(Output & output, uint32_t& ind, const RegExpMap* specMap, const s
        }
 
        std::set<uint32_t> used_labels;
-       count_used_labels (used_labels, prolog_label, start_label, o.get_force_start_label ());
+       count_used_labels (used_labels, start_label, initial_label, o.get_force_start_label ());
 
        // Generate prolog
        if (bProlog)
@@ -173,9 +172,9 @@ void DFA::emit(Output & output, uint32_t& ind, const RegExpMap* specMap, const s
                o.insert_state_goto (ind);
                if (cFlag && !DFlag)
                {
-                       if (used_labels.count(prolog_label))
+                       if (used_labels.count(start_label))
                        {
-                               o << labelPrefix << prolog_label << ":\n";
+                               o << labelPrefix << start_label << ":\n";
                        }
                }
                o.write_user_start_label ();
@@ -204,10 +203,12 @@ void DFA::emit(Output & output, uint32_t& ind, const RegExpMap* specMap, const s
                BitMap::gen(o, ind, lbChar, ubChar <= 256 ? ubChar : 256);
        }
 
-       // The start_label is not always the first to be emitted, so we may have to jump. c.f. Initial::emit()
+       // If DFA has transitions to initial state, then initial state
+       // has a piece of code that advances input position. Wee must
+       // skip it when entering DFA.
        if (used_labels.count(head->label))
        {
-               o << indent(ind) << "goto " << labelPrefix << start_label << ";\n";
+               o << indent(ind) << "goto " << labelPrefix << initial_label << ";\n";
        }
 
        // Generate code