Fixes some hidden NULL pointer dereferencing.

'specMap' parameter can sometimes be NULL (when not in '-c' mode).
In code it was dereferenced before the check for '-c', but due to
compiler optimizations this was never revealed.

I found the bug while trying to measure the size of 'specMap'
before the check (caught segfault). Fixed by moving the check prior
to dereferencing.

diff --git a/re2c/src/codegen/emit_dfa.cc b/re2c/src/codegen/emit_dfa.cc
index 11653a34dc81eebb65eb2210a5d129e1d99916b8..ad70102195d5f2f51ea647ea9167264636b20b7a 100644 (file)
--- a/re2c/src/codegen/emit_dfa.cc
+++ b/re2c/src/codegen/emit_dfa.cc
@@ -128,7 +128,7 @@ void DFA::emit(Output & output, uint32_t& ind, const RegExpMap* specMap, const s
                else if ((!fFlag && o.get_used_yyaccept ())
                ||  (!fFlag && bEmitYYCh)
                ||  (bFlag && !cFlag && BitMap::first)
-               ||  (cFlag && !bWroteCondCheck && gFlag && !specMap->empty())
+               ||  (cFlag && !bWroteCondCheck && gFlag && specMap)
                ||  (fFlag && !bWroteGetState && gFlag)
                )
                {
@@ -159,7 +159,10 @@ void DFA::emit(Output & output, uint32_t& ind, const RegExpMap* specMap, const s
        }
        if (bProlog)
        {
-               genCondTable(o, ind, *specMap);
+               if (cFlag && !bWroteCondCheck && gFlag && specMap)
+               {
+                       genCondTable(o, ind, *specMap);
+               }
                o.insert_state_goto (ind);
                if (cFlag && !DFlag)
                {
@@ -169,7 +172,10 @@ void DFA::emit(Output & output, uint32_t& ind, const RegExpMap* specMap, const s
                        }
                }
                o.write_user_start_label ();
-               genCondGoto(o, ind, *specMap);
+               if (cFlag && !bWroteCondCheck && specMap)
+               {
+                       genCondGoto(o, ind, *specMap);
+               }
        }
 
        if (cFlag && !condName.empty())
@@ -236,23 +242,21 @@ void DFA::emit(Output & output, uint32_t& ind, const RegExpMap* specMap, const s
 
 void genCondTable(OutputFile & o, uint32_t ind, const RegExpMap& specMap)
 {
-       if (cFlag && !bWroteCondCheck && gFlag && specMap.size())
-       {
-               RegExpIndices  vCondList(specMap.size());
+       const uint32_t specMap_size = static_cast<uint32_t> (specMap.size ());
+       RegExpIndices  vCondList(specMap_size);
 
-               for(RegExpMap::const_iterator itSpec = specMap.begin(); itSpec != specMap.end(); ++itSpec)
-               {
-                       vCondList[itSpec->second.first] = itSpec->first;
-               }
+       for(RegExpMap::const_iterator itSpec = specMap.begin(); itSpec != specMap.end(); ++itSpec)
+       {
+               vCondList[itSpec->second.first] = itSpec->first;
+       }
 
-               o << indent(ind++) << "static void *" << mapCodeName["yyctable"] << "[" << specMap.size() << "] = {\n";
+       o << indent(ind++) << "static void *" << mapCodeName["yyctable"] << "[" << specMap_size << "] = {\n";
 
-               for(RegExpIndices::const_iterator it = vCondList.begin(); it != vCondList.end(); ++it)
-               {
-                       o << indent(ind) << "&&" << condPrefix << *it << ",\n";
-               }
-               o << indent(--ind) << "};\n";
+       for(RegExpIndices::const_iterator it = vCondList.begin(); it != vCondList.end(); ++it)
+       {
+               o << indent(ind) << "&&" << condPrefix << *it << ",\n";
        }
+       o << indent(--ind) << "};\n";
 }
 
 void genCondGotoSub(OutputFile & o, uint32_t ind, RegExpIndices& vCondList, uint32_t cMin, uint32_t cMax)
@@ -275,44 +279,41 @@ void genCondGotoSub(OutputFile & o, uint32_t ind, RegExpIndices& vCondList, uint
 
 void genCondGoto(OutputFile & o, uint32_t ind, const RegExpMap& specMap)
 {
-       if (cFlag && !bWroteCondCheck && specMap.size())
+       if (gFlag)
        {
-               if (gFlag)
-               {
-                       o << indent(ind) << "goto *" << mapCodeName["yyctable"] << "[" << genGetCondition() << "];\n";
-               }
-               else
+               o << indent(ind) << "goto *" << mapCodeName["yyctable"] << "[" << genGetCondition() << "];\n";
+       }
+       else
+       {
+               if (sFlag)
                {
-                       if (sFlag)
+                       RegExpIndices  vCondList(specMap.size());
+               
+                       for(RegExpMap::const_iterator it = specMap.begin(); it != specMap.end(); ++it)
                        {
-                               RegExpIndices  vCondList(specMap.size());
-                       
-                               for(RegExpMap::const_iterator it = specMap.begin(); it != specMap.end(); ++it)
-                               {
-                                       vCondList[it->second.first] = it->first;
-                               }
-                               genCondGotoSub(o, ind, vCondList, 0, vCondList.size() - 1);
+                               vCondList[it->second.first] = it->first;
                        }
-                       else if (DFlag)
+                       genCondGotoSub(o, ind, vCondList, 0, static_cast<uint32_t> (vCondList.size()) - 1);
+               }
+               else if (DFlag)
+               {
+                       for(RegExpMap::const_iterator it = specMap.begin(); it != specMap.end(); ++it)
                        {
-                               for(RegExpMap::const_iterator it = specMap.begin(); it != specMap.end(); ++it)
-                               {
-                                       o << "0 -> " << it->first << " [label=\"state=" << it->first << "\"]\n";
-                               }
+                               o << "0 -> " << it->first << " [label=\"state=" << it->first << "\"]\n";
                        }
-                       else
+               }
+               else
+               {
+                       o << indent(ind) << "switch (" << genGetCondition() << ") {\n";
+
+                       for(RegExpMap::const_iterator it = specMap.begin(); it != specMap.end(); ++it)
                        {
-                               o << indent(ind) << "switch (" << genGetCondition() << ") {\n";
-       
-                               for(RegExpMap::const_iterator it = specMap.begin(); it != specMap.end(); ++it)
-                               {
-                                       o << indent(ind) << "case " << condEnumPrefix << it->first << ": goto " << condPrefix << it->first << ";\n";
-                               }
-                               o << indent(ind) << "}\n";
+                               o << indent(ind) << "case " << condEnumPrefix << it->first << ": goto " << condPrefix << it->first << ";\n";
                        }
+                       o << indent(ind) << "}\n";
                }
-               bWroteCondCheck = true;
        }
+       bWroteCondCheck = true;
 }
 
 void genTypes(Output & output, const RegExpMap& specMap)