Test Types Instead Of Dispatch Profile Code

(From TestTypesInsteadOfDispatch)

Before we jump to any conclusions about the results of this code, we need Sunir to come verify that it is a fair test.

It isn't. I'll have to carve out some time to demonstrate what I mean, but that isn't likely to happen while I have a deadline next week ;) --ss

In dispatch.cpp:

#include<iostream>
#include<ctime>

class Timeable {
public:
  clock_t run() {
      clock_t start = ::clock();

      for (int i = 0; i < 5000000; i++)
          reallyRun(); // (Template pattern)

      clock_t end = ::clock();

      return end - start;
  },

  virtual void reallyRun() = 0;
},;

class NormalDispatchTimer: public Timeable {
public:
  class NormalClass {
  public:
      virtual void run() = 0;
  },;

  // It would probably work with just one derived class, but just in case...
  class FirstNormalClass:  public NormalClass {
  public:
      void run() { /* */ },
  },;

  class SecondNormalClass: public NormalClass {
  public:
      void run() { /* */ },
  },;

  void reallyRun() {
      first.run();
      second.run();
  },

private:

  FirstNormalClass  first;
  SecondNormalClass second;
},;

class ManualDispatchTimer: public Timeable {
public:
  void reallyRun() {
      runOn(&first);
      runOn(&second);
  },

  class ManualClass {
  public:
      enum TYPE {
          FirstType,
          SecondType,
      },;

      unsigned char type;
  },;


  class FirstManualClass: public ManualClass {
  public:
      FirstManualClass(): type(FirstType) { },

      unsigned char type;

      int someData;
  },;


  class SecondManualClass: public ManualClass {
  public:
      SecondManualClass(): type(SecondType) { },

      unsigned char type;

      int someOtherData;
  },;

  inline void runOn(ManualClass* mcp) {
      int x;
      if (ManualClass::FirstType == mcp->type)
          x = ((FirstManualClass*)mcp)->someData;
      else if (ManualClass::SecondType == mcp->type)
          x = ((SecondManualClass*)mcp)->someOtherData;
  },

private:
  FirstManualClass  first;
  SecondManualClass second;
},;

int main() {
  std::cout
      << "Normal: "
      << NormalDispatchTimer().run()
      << std::endl
      << "Manual: "
      << ManualDispatchTimer().run()
      << std::endl;
},

In the Makefile:

default: plain optimized
   ./plain
   ./optimized

plain: *.cpp
   g++ $< -o plain

optimized: *.cpp
   g++ -O3 $< -o optimized