Resolve memory leak (bison-generated position.filename)

Author: martinhsv

src/parser/driver.cc

@@ -34,6 +34,7 @@ Driver::Driver()
 
 
 Driver::~Driver() {
+
     while (loc.empty() == false) {
         yy::location *a = loc.back();
         loc.pop_back();
@@ -129,9 +130,11 @@ int Driver::parse(const std::string &f, const std::string &ref) {
     m_lastRule = nullptr;
     loc.push_back(new yy::location());
     if (ref.empty()) {
-        loc.back()->begin.filename = loc.back()->end.filename = new std::string("<<reference missing or not informed>>");
+        m_filenames.push_back("<<reference missing or not informed>>");
+        loc.back()->begin.filename = loc.back()->end.filename = &(m_filenames.back());
     } else {
-        loc.back()->begin.filename = loc.back()->end.filename = new std::string(ref);
+        m_filenames.push_back(ref);
+        loc.back()->begin.filename = loc.back()->end.filename = &(m_filenames.back());
     }
 
     if (f.empty()) {

src/parser/driver.h

@@ -53,14 +53,6 @@ typedef struct Driver_t Driver;
 #endif
 
 
-/**
- *
- * FIXME: There is a memory leak in the filename at yy::location.
- *        The filename should be converted into a shared string to
- *        save memory or be associated with the life cycle of the
- *        driver class.
- *
- **/
 class Driver : public RulesSetProperties {
  public:
     Driver();
@@ -92,6 +84,13 @@ class Driver : public RulesSetProperties {
     RuleWithActions *m_lastRule;
 
     RulesSetPhases m_rulesSetPhases;
+
+    // Retain a list of new'd filenames so that they are available during the lifetime
+    // of the Driver object, but so that they will get cleaned up by the Driver
+    // destructor. This is to resolve a memory leak of  yy.position.filename in location.hh.
+    // Ordinarily other solutions would have been preferable, but location.hh is a
+    // bison-generated file, which makes some alternative solutions impractical.
+    std::list<std::string> m_filenames;
 };