Hi, Lassi, thanks for filling in that detailed report. Here are some notes to reduce the amount of wrong conclusions a reader might jump to. Lassi Tuura wrote:
Hi,
It's not the first time I've seen this, and I still do not understand what the belief of template meta-programming causing bloat is based on.
Maybe I can help with that. For simple toys and well-contained programs, the compiler can do a lot to inline, as was kindly shown by someone. But take an application of ours as an example from somewhat more real software world.
<... snip ...> We should not confuse template metaprogramming with too many template instantiations: What's causing the bloat is multiplying code or data by instantiating templates *not* metaprograms, since metaprograms instantiate neither code nor data - just types. In fact, the last code sample from the discussion with Ion presents a metaprogram to /reduce/ the bloat effect. Redundancy reduction and even inlining can work with static linking (given a proper linker, that is. Note GCC is rather poor when it comes to such things, BTW). Dynamic libraries provide a barrier for these kinds of optimizations and there's not much a C++ ABI can do about it, as the loader is provided by the operating system (note inlining would even require some kind of JIT compiler for the loader, BTW). Also, dynamic libraries (which are typically overused often for the sake of simplicity) and promote code bloat: Unlike with static linking, dynamic libraries have to be loaded as a whole and unused parts can't be discarded (unless via swapped out memory pages). Regards, Tobias