Use C++20

[SiarheiFedartsou]

I believe it is a time to bump C++ standard in this project. It has quite a lot of useful things OSRM can benefit from(e.g. std::span and also I see that even json_render benchmark became better due to some reason :) ). I hope there are no objections for this.

Benchmark Results

Benchmark	Base	PR
alias	aliased u32: 1094.05 plain u32: 1092.11 aliased double: 960.248 plain double: 947.363	aliased u32: 1091.75 plain u32: 1089.74 aliased double: 959.988 plain double: 948.72
json-render	String: 8.2719ms Stringstream: 11.5894ms Vector: 7.47187ms	String: 6.75741ms Stringstream: 10.5255ms Vector: 6.62243ms
match_ch	Default radius: 4.43728ms/req at 82 coordinate 0.0541131ms/coordinate Radius 5m: 4.43271ms/req at 82 coordinate 0.0540574ms/coordinate Radius 10m: 15.0005ms/req at 82 coordinate 0.182933ms/coordinate Radius 15m: 36.5988ms/req at 82 coordinate 0.446327ms/coordinate Radius 30m: 312.388ms/req at 82 coordinate 3.80961ms/coordinate	Default radius: 4.53578ms/req at 82 coordinate 0.0553144ms/coordinate Radius 5m: 4.53172ms/req at 82 coordinate 0.0552649ms/coordinate Radius 10m: 15.343ms/req at 82 coordinate 0.18711ms/coordinate Radius 15m: 37.2938ms/req at 82 coordinate 0.454803ms/coordinate Radius 30m: 319.071ms/req at 82 coordinate 3.89112ms/coordinate
match_mld	Default radius: 2.88705ms/req at 82 coordinate 0.035208ms/coordinate Radius 5m: 2.80234ms/req at 82 coordinate 0.0341749ms/coordinate Radius 10m: 10.1313ms/req at 82 coordinate 0.123553ms/coordinate Radius 15m: 25.6745ms/req at 82 coordinate 0.313104ms/coordinate Radius 30m: 297.859ms/req at 82 coordinate 3.63243ms/coordinate	Default radius: 2.87119ms/req at 82 coordinate 0.0350145ms/coordinate Radius 5m: 2.86241ms/req at 82 coordinate 0.0349074ms/coordinate Radius 10m: 10.4629ms/req at 82 coordinate 0.127596ms/coordinate Radius 15m: 26.7566ms/req at 82 coordinate 0.3263ms/coordinate Radius 30m: 314.468ms/req at 82 coordinate 3.83497ms/coordinate
packedvector	random write: std::vector 9813.3 ms util::packed_vector 74360.7 ms slowdown: 7.57755 random read: std::vector 8675.09 ms util::packed_vector 30857.7 ms slowdown: 3.55704	random write: std::vector 9754.69 ms util::packed_vector 81460.1 ms slowdown: 8.35087 random read: std::vector 8478.48 ms util::packed_vector 31332 ms slowdown: 3.69548
route_ch	1000 routes, 3 coordinates, no alternatives, overview=full, steps=true 597.456ms 0.597456ms/req 1000 routes, 2 coordinates, no alternatives, overview=full, steps=true 379.2ms 0.3792ms/req 1000 routes, 2 coordinates, 3 alternatives, overview=full, steps=true 763.511ms 0.763511ms/req 1000 routes, 3 coordinates, no alternatives, overview=false, steps=false 161.229ms 0.161229ms/req 1000 routes, 2 coordinates, no alternatives, overview=false, steps=false 103.889ms 0.103889ms/req 1000 routes, 2 coordinates, 3 alternatives, overview=false, steps=false 146.011ms 0.146011ms/req 1000 routes, 3 coordinates, no alternatives, overview=false, steps=false, radius=750 161.279ms 0.161279ms/req 1000 routes, 2 coordinates, no alternatives, overview=false, steps=false, radius=750 103.87ms 0.10387ms/req 1000 routes, 2 coordinates, 3 alternatives, overview=false, steps=false, radius=750 144.998ms 0.144998ms/req	1000 routes, 3 coordinates, no alternatives, overview=full, steps=true 596.23ms 0.59623ms/req 1000 routes, 2 coordinates, no alternatives, overview=full, steps=true 376.829ms 0.376829ms/req 1000 routes, 2 coordinates, 3 alternatives, overview=full, steps=true 763.386ms 0.763386ms/req 1000 routes, 3 coordinates, no alternatives, overview=false, steps=false 161.562ms 0.161562ms/req 1000 routes, 2 coordinates, no alternatives, overview=false, steps=false 104.426ms 0.104426ms/req 1000 routes, 2 coordinates, 3 alternatives, overview=false, steps=false 144.873ms 0.144873ms/req 1000 routes, 3 coordinates, no alternatives, overview=false, steps=false, radius=750 160.242ms 0.160242ms/req 1000 routes, 2 coordinates, no alternatives, overview=false, steps=false, radius=750 104.019ms 0.104019ms/req 1000 routes, 2 coordinates, 3 alternatives, overview=false, steps=false, radius=750 144.505ms 0.144505ms/req
route_mld	1000 routes, 3 coordinates, no alternatives, overview=full, steps=true 722.484ms 0.722484ms/req 1000 routes, 2 coordinates, no alternatives, overview=full, steps=true 467.443ms 0.467443ms/req 1000 routes, 2 coordinates, 3 alternatives, overview=full, steps=true 946.061ms 0.946061ms/req 1000 routes, 3 coordinates, no alternatives, overview=false, steps=false 280.552ms 0.280552ms/req 1000 routes, 2 coordinates, no alternatives, overview=false, steps=false 168.964ms 0.168964ms/req 1000 routes, 2 coordinates, 3 alternatives, overview=false, steps=false 304.268ms 0.304268ms/req 1000 routes, 3 coordinates, no alternatives, overview=false, steps=false, radius=750 280.978ms 0.280978ms/req 1000 routes, 2 coordinates, no alternatives, overview=false, steps=false, radius=750 168.926ms 0.168926ms/req 1000 routes, 2 coordinates, 3 alternatives, overview=false, steps=false, radius=750 300.273ms 0.300273ms/req	1000 routes, 3 coordinates, no alternatives, overview=full, steps=true 727.123ms 0.727123ms/req 1000 routes, 2 coordinates, no alternatives, overview=full, steps=true 469.123ms 0.469123ms/req 1000 routes, 2 coordinates, 3 alternatives, overview=full, steps=true 956.257ms 0.956257ms/req 1000 routes, 3 coordinates, no alternatives, overview=false, steps=false 286.806ms 0.286806ms/req 1000 routes, 2 coordinates, no alternatives, overview=false, steps=false 167.625ms 0.167625ms/req 1000 routes, 2 coordinates, 3 alternatives, overview=false, steps=false 306.994ms 0.306994ms/req 1000 routes, 3 coordinates, no alternatives, overview=false, steps=false, radius=750 280.106ms 0.280106ms/req 1000 routes, 2 coordinates, no alternatives, overview=false, steps=false, radius=750 167.448ms 0.167448ms/req 1000 routes, 2 coordinates, 3 alternatives, overview=false, steps=false, radius=750 305.274ms 0.305274ms/req
rtree	1 result: 208.935ms -> 0.0208935 ms/query 10 results: 244.479ms -> 0.0244479 ms/query	1 result: 207.379ms -> 0.0207379 ms/query 10 results: 242.495ms -> 0.0242495 ms/query

[SiarheiFedartsou]

There were problems with Boost from apt on Ubuntu 22.04, so I propose to install it manually for the time being.

[DennisOSRM]

Would a switch to 24.04 make this easier?

[SiarheiFedartsou]

Well, with a switch to 24.04 I had another challenge: sol2 is not compiling with newest clang we would have to switch to on 24.04. There is already fix in LLVM, so I believe it is just easier to wait for a while until this fix will come to GitHub Actions runner image for 24.04 and switch.

[cuavas]

The fix is only going to make it to clang 19, unfortunately.

[DennisOSRM]

How about adding a ticket into the backlog to fix these warnings?

[SiarheiFedartsou]

Sure, #6902

[DennisOSRM]

Would a switch to 24.04 make this easier?

[DennisOSRM]

Great change!