Remove unneeded EmitterVisitor::m_methLabels

EmitterVisitor::m_methLabels is used for 2 purposes:

- avoid emitting generator body twice
- fatal at the import time when file contains already defined function

The labels themselves are not used as labels, comments suggests it used
to be used for fast calls.

Replace them with 2 dedicated sets: m_generatorEmitted flag for generator bodies, m_topMethodEmitted for functions.

hphp/compiler/analysis/emitter.cpp

@@ -1159,10 +1159,6 @@ EmitterVisitor::EmitterVisitor(UnitEmitter& ue)
 }
 
 EmitterVisitor::~EmitterVisitor() {
-  for (LabelMap::const_iterator it = m_methLabels.begin();
-       it != m_methLabels.end(); it++) {
-    delete it->second;
-  }
   // If a fatal occurs during emission, some extra cleanup is necessary.
   for (std::deque<ExnHandlerRegion*>::const_iterator it = m_exnHandlers.begin();
        it != m_exnHandlers.end(); ++it) {
@@ -1641,10 +1637,6 @@ void EmitterVisitor::visit(FileScopePtr file) {
   for (i = 0; i < nk; i++) {
     StatementPtr s = (*stmts)[i];
     if (MethodStatementPtr meth = dynamic_pointer_cast<MethodStatement>(s)) {
-      // Create label for use with fast calls
-      const StringData* methName =
-        StringData::GetStaticString(meth->getOriginalName());
-      m_methLabels[methName] = new Label();
       // Emit afterwards
       postponeMeth(meth, nullptr, true);
     }
@@ -2574,11 +2566,8 @@ bool EmitterVisitor::visitImpl(ConstructPtr node) {
             // with its own file.
             return false;
           }
-          Label*& label = m_methLabels[nName];
-          if (!label) {
+          if (!m_generatorEmitted.insert(m->getOriginalName()).second) {
             // its possible to see the same generator more than once
-            label = new Label();
-          } else {
             return false;
           }
 
@@ -5264,18 +5253,11 @@ void EmitterVisitor::emitPostponedMeths() {
     }
     Emitter e(p.m_meth, m_ue, *this);
     if (p.m_top) {
-      StringData* methName =
-        StringData::GetStaticString(p.m_meth->getOriginalName());
-      auto entry = m_methLabels.find(methName);
-      if (entry != m_methLabels.end() && entry->second->isSet()) {
-        // According to Zend, this is include-time; Zend doesn't appear
-        // to execute the pseudomain that redeclares.
-        throw IncludeTimeFatalException(p.m_meth,
-                                        (string("Function already defined: ") +
-                                         string(methName->data())).c_str());
-      } else {
-        // Set label
-        m_methLabels[methName]->set(e);
+      if (!m_topMethodEmitted.insert(p.m_meth->getOriginalName()).second) {
+        throw IncludeTimeFatalException(
+          p.m_meth,
+          (string("Function already defined: ") +
+           p.m_meth->getOriginalName()).c_str());
       }
     }
     typedef std::pair<Id, ConstructPtr> DVInitializer;

hphp/compiler/analysis/emitter.h

@@ -515,8 +515,8 @@ private:
   std::deque<PostponedNonScalars> m_postponedCinits;
   std::deque<PostponedClosureCtor> m_postponedClosureCtors;
   PendingIterVec m_pendingIters;
-  typedef std::map<const StringData*, Label*, string_data_lt> LabelMap;
-  LabelMap m_methLabels;
+  hphp_hash_set<std::string> m_generatorEmitted;
+  hphp_hash_set<std::string> m_topMethodEmitted;
   SymbolicStack m_evalStack;
   bool m_evalStackIsUnknown;
   hphp_hash_map<Offset, SymbolicStack> m_jumpTargetEvalStacks;