Fix incorrect use of std::unique

[jingham]

This bug has been there since the first llvm.org checkin. I'm curious, did it actually cause a problem or did you just see it while reading?

The patch is right. Most of the other uses elide storing the position the non-unique elements got moved to, and does "indexes.erase(std::unique...)" but either form is fine by me.

[eugene]

clang drew my attention to it:

Symtab.cpp:620:5: warning: ignoring return value of function declared with 'warn_unused_result' attribute [-Wunused-result]

std::unique(indexes.begin(), indexes.end());
^~~~~~~~~~~ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

[eugene]

Checked in as r309648

source/Symbol/Symtab.cpp

void Symtab::SortSymbolIndexesByValue(std::vector<uint32_t> &indexes,
   // stable sort handles better.
 
   std::vector<lldb::addr_t> addr_cache(m_symbols.size(), LLDB_INVALID_ADDRESS);
 
   SymbolIndexComparator comparator(m_symbols, addr_cache);
   std::stable_sort(indexes.begin(), indexes.end(), comparator);
 
   // Remove any duplicates if requested
-  if (remove_duplicates)
-    std::unique(indexes.begin(), indexes.end());
+  if (remove_duplicates) {
+    auto last = std::unique(indexes.begin(), indexes.end());
+    indexes.erase(last, indexes.end());
+  }
 }
 
 uint32_t Symtab::AppendSymbolIndexesWithName(const ConstString &symbol_name,
                                              std::vector<uint32_t> &indexes) {
   std::lock_guard<std::recursive_mutex> guard(m_mutex);
 
   static Timer::Category func_cat(LLVM_PRETTY_FUNCTION);
   Timer scoped_timer(func_cat, "%s", LLVM_PRETTY_FUNCTION);