This is all solid advice (particularly using a faster linker).
IME, the single best way to reduce your C++ compile times is to compile less code:
* Remove all unnecessary headers. Template expansion is slow, and preprocessing is even slower. Some of the standard includes (like `<regex>` and `<iostream>`) are notorious for slowing individual translation units to a crawl. `#pragma once` for your own headers also helps with cpp-time performance.
* Forward-declare as much as you can. Forward type declarations mean that the compiler doesn't need to process all of `Foo` when it sees `Foo&` or `Foo`.
Use pImpl wherever you can (and makes sense). Private implementations similarly reduce the amount of code the compiler needs to analyze.
For better or worse, the current winds suggest that C++ compilation times will only continue to get worse (more constexpr/consteval, even more complex templating features/concepts, etc.).
IME, the single best way to reduce your C++ compile times is to compile less code:
* Remove all unnecessary headers. Template expansion is slow, and preprocessing is even slower. Some of the standard includes (like `<regex>` and `<iostream>`) are notorious for slowing individual translation units to a crawl. `#pragma once` for your own headers also helps with cpp-time performance.
* Forward-declare as much as you can. Forward type declarations mean that the compiler doesn't need to process all of `Foo` when it sees `Foo&` or `Foo`.
Use pImpl wherever you can (and makes sense). Private implementations similarly reduce the amount of code the compiler needs to analyze.
For better or worse, the current winds suggest that C++ compilation times will only continue to get worse (more constexpr/consteval, even more complex templating features/concepts, etc.).