Size of 64-bit dll 50% larger than 32-bit

64-bit, c++, visual-c++

Solution

Maybe your code contains a lot of pointers.

The Free Lunch Is Over

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(Aside: Here’s an anecdote to demonstrate “space is speed” that recently hit my compiler team. The compiler uses the same source base for the 32-bit and 64-bit compilers; the code is just compiled as either a 32-bit process or a 64-bit one. The 64-bit compiler gained a great deal of baseline performance by running on a 64-bit CPU, principally because the 64-bit CPU had many more registers to work with and had other code performance features. All well and good. But what about data? Going to 64 bits didn’t change the size of most of the data in memory, except that of course pointers in particular were now twice the size they were before. As it happens, our compiler uses pointers much more heavily in its internal data structures than most other kinds of applications ever would. Because pointers were now 8 bytes instead of 4 bytes, a pure data size increase, we saw a significant increase in the 64-bit compiler’s working set. That bigger working set caused a performance penalty that almost exactly offset the code execution performance increase we’d gained from going to the faster processor with more registers. As of this writing, the 64-bit compiler runs at the same speed as the 32-bit compiler, even though the source base is the same for both and the 64-bit processor offers better raw processing throughput. Space is speed.)

Problem

Original source