Function compilations

In this page we'll explore which info you can get from the FunctionCompilations.csv report.

If we were to check the sample file provided in the repo we would find something like this:

Undecorated function name	Average elapsed time (nanoseconds)	Minimum elapsed time (nanoseconds)	Maximum elapsed time (nanoseconds)	Standard deviation (nanoseconds)	Occurrences
void * __ptr64 __cdecl operator new(unsigned __int64,void * __ptr64)	9886794	207600	89488000	27283727	18
unsigned __int64 __cdecl std::_Get_size_of_n<16>(unsigned __int64)	8058894	263000	69892400	21849490	18
void __cdecl std::_Deallocate<16,0>(void * __ptr64,unsigned __int64)	4164733	279800	69553600	15859163	18
...	...	...	...	...	...

Similar to other reports, we get the average time and related metrics.
Remember: functions are getting compiled in parallel, so adding individual occurrences together wouldn't yield a valid total.

Rule of thumb

Having a function that gets compiled many times and takes a high average should hint you for improvements.

What now?

Say you've found some function whose impact in the build you want to improve. Ask yourself some questions:

• Should it be compiled these many times, at all? Maybe it's a default constructor provided by the compiler and you could implement one yourself in the .cpp file.
• Should it take this long? Maybe you're performing a lot of compile-time operations.