[compiler-rt] [llvm] [asan] Limit priority of ctor to kMax-1 (PR #101772)

[Fangrui Song via llvm-commits]

MaskRay wrote:

> > asan changing the priority of a llvm.global_ctors element might be surprising. Is this change to work with some specific code or specific IR code generators that use 65535 (instrumentation cannot do anything with `.init_array.65535` in inline assembly)? Can we change these tools instead?
> 
> No. The goal to be able to call `asan` runtime callback just after the last dynamic constructor.

Is there more information about this decision? What would break if the order is different?

So priority 65535 is unsuffixed `.init_array`. Lots of code might use inline asm `.section .init_array,"aw", at init_array`.
Instrumentation cannot safely do anything with them (e.g. adding `.65534` suffix).

https://github.com/llvm/llvm-project/pull/101772