[clang] [llvm] [BPF] Support Stack Arguments (PR #189060)

[via cfe-commits]

4ast wrote:

> 
> For x86, we also did 'sp -= ' before the call. With this, for '*(u64 *)(r12 - off) = ' can directly put the value in the expected stack location. After the call, the jit will do 'sp += ' to go to the place where all "pushed" values are gone.

if JIT did 'sp -=' just before the call then it's broken. The code cannot store into sp - X before sp -=, since IRQ will corrupt it.
Hence my earlier point that JIT has to insert 'sp -=' before the actual stores.


https://github.com/llvm/llvm-project/pull/189060