Resolve "refactor(build): simplify PCH usage"
Description
To solve the issues described in #948 (closed), we now provide a single pch file. It only contains 3rd part libraries headers. The list was extracted from the previous pchServices recursive list, by removing all sight headers. It is also built in a second version for the targets that use optimized debug builds. During tests, we realized the build timings remain stable and even outperform sometimes the previous approach.
On Clang, we also took the opportunity to use a new feature that speedups PCH builds: http://llunak.blogspot.com/2021/04/clang-precompiled-headers-and-improving.html. The gain was measured at 10%.
This should allow using PCH builds reliably on the CI runners.
Closes #948 (closed)
Extra changes
- OpenMP is now enabled globally. This should be safe on modern compilers and target architectures.
- While looking for the minimal std/boost headers set, some cleaning was done to remove unused headers or deprecated symbols/files.
How to test it?
- Nothing special.
Some results
| PCH | Compiler | Target | Build | %CPU | Time |
|---|---|---|---|---|---|
| Old | Clang | SightViewer | Debug | 1126 | 5:57 |
| New | Clang | SightViewer | Debug | 1148 | 5:14 |
| Old | GCC | SightViewer | Debug | 1138 | 8:36 |
| New | GCC | SightViewer | Debug | 1106 | 7:52 |
| Old | MSVC | SightViewer | Debug | 1138 | 7:30 |
| New | MSVC | SightViewer | Debug | 1106 | 7:56 |
| Old | GCC | SightViewer | Release | 1119 | 9:15 |
| New | GCC | SightViewer | Release | 1136 | 9:15 |