Use MapVector to fix lld thinLTO nondeterminism issue.

    When the ModuleSymbolTable is generated, the
    binary consistency problem occurs due to the
    unorder of the data structure when collecting
    asm symbols.

Author: llvmssh

llvm/lib/Object/RecordStreamer.h

@@ -11,6 +11,7 @@
 
 #include "llvm/ADT/DenseMap.h"
 #include "llvm/ADT/StringMap.h"
+#include "llvm/ADT/MapVector.h"
 #include "llvm/MC/MCDirectives.h"
 #include "llvm/MC/MCStreamer.h"
 #include "llvm/Support/SMLoc.h"
@@ -32,7 +33,7 @@ class RecordStreamer : public MCStreamer {
   // Map of aliases created by .symver directives, saved so we can update
   // their symbol binding after parsing complete. This maps from each
   // aliasee to its list of aliases.
-  DenseMap<const MCSymbol *, std::vector<StringRef>> SymverAliasMap;
+  MapVector<const MCSymbol *, std::vector<StringRef>> SymverAliasMap;
 
   /// Get the state recorded for the given symbol.
   State getSymbolState(const MCSymbol *Sym);