The ModuleLevel vector is often quite sparse. Switch it to a DenseMap. This

speeds up bcwriting of 447.dealII by 40%, from 4.63s to 3.32s.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@34135 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Bytecode/Writer/SlotCalculator.h

@@ -20,6 +20,7 @@
 #ifndef LLVM_ANALYSIS_SLOTCALCULATOR_H
 #define LLVM_ANALYSIS_SLOTCALCULATOR_H
 
+#include "llvm/ADT/DenseMap.h"
 #include <vector>
 #include <map>
 
@@ -34,6 +35,14 @@ class TypeSymbolTable;
 class ValueSymbolTable;
 class ConstantArray;
 
+struct ModuleLevelDenseMapKeyInfo {
+  static inline unsigned getEmptyKey() { return ~0U; }
+  static inline unsigned getTombstoneKey() { return ~1U; }
+  static unsigned getHashValue(unsigned Val) { return Val ^ Val >> 4; }
+  static bool isPod() { return true; }
+};
+
+
 class SlotCalculator {
   const Module *TheModule;
 
@@ -54,8 +63,8 @@ class SlotCalculator {
   /// ModuleLevel - Used to keep track of which values belong to the module,
   /// and which values belong to the currently incorporated function.
   ///
-  std::vector<int> ModuleLevel;
-  unsigned ModuleTypeLevel;
+  DenseMap<unsigned,unsigned,ModuleLevelDenseMapKeyInfo> ModuleLevel;
+  unsigned NumModuleTypes;
 
   SlotCalculator(const SlotCalculator &);  // DO NOT IMPLEMENT
   void operator=(const SlotCalculator &);  // DO NOT IMPLEMENT