[clang] [clang-tools-extra] [llvm] [OptTable] Store Info strings in the string table (PR #218845)

[Fangrui Song via llvm-commits]

MaskRay wrote:

> I guess this only improves relocations but not .data.rel.ro size and the c-t-t size wins come largely from the fact that c-t-t uses rela instead of relr? Or does this move the entire table to .rodata?

The whole table. clang's DriverOptions.cpp.o:

|                           | baseline                    | patch                 |
|---------------------------|-----------------------------|-----------------------|
| InfoTable                 | .data.rel.ro, 336,248 B, WA | .rodata, 229,260 B, A |
| relocations against it    | 2751                        | 0                     |
| object total .data.rel.ro | 336,328 B                   | 80 B                  |

sizeof(Info) size: goes 88 → 60

https://github.com/llvm/llvm-project/pull/218845