Use the SymbolTable::isEmpty() method instead of checking for no value

planes. A SymbolTable could still have types in it! This fixes problems
with two regression tests that failed because a symbol table that only
contained types was being omitted from bytecode files. Thanks to Chris
for the reduced test case that helped find this immediately.

llvm-svn: 13842

llvm/lib/Bytecode/Writer/Writer.cpp

@@ -307,7 +307,7 @@ void BytecodeWriter::outputCompactionTable() {
 void BytecodeWriter::outputSymbolTable(const SymbolTable &MST) {
   // Do not output the Bytecode block for an empty symbol table, it just wastes
   // space!
-  if (MST.plane_begin() == MST.plane_end()) return;
+  if ( MST.isEmpty() ) return;
 
   BytecodeBlock SymTabBlock(BytecodeFormat::SymbolTable, Out,
                             true/* ElideIfEmpty*/);