[compiler-rt] [llvm] [AArch64] Implement INIT/ADJUST_TRAMPOLINE (PR #70267)

[David Truby via llvm-commits]

DavidTruby wrote:

> I noticed this today as well. It wasn't happening when I first submitted the patch a long time ago. Did something change in compiler-rt that may affect this?

I don't think anything changed; we don't link to compiler-rt on Linux, instead we link to libgcc_s. Clang does this by default too but has a flag to choose compiler-rt instead. I don't have the __start_trampoline symbol in libgcc_s on my system so I guess we'll need to require compiler-rt for this.

I don't think that invalidates the patch, at least as a stopgap until we can get non-executable stack trampolines working. On x86 LLVM doesn't require an external function for this, it just does the code inline. I'm guessing that's quite difficult to do here?

https://github.com/llvm/llvm-project/pull/70267