[llvm] [Xtensa] Implement base CallConvention. (PR #83280)

[Sergei Barannikov via llvm-commits]

s-barannikov wrote:

I wouldn't mind if this PR included LowerCall implementation, it won't be much different from LowerFormalArguments/LowerReturn. The tests could then just call a function with the same signature so that we can see how arguments are recieved and passed.
The PR should also include XtensaFrameLowering changes, at least a part of them, so that the tests are representative.
There should be tests for passing arguments on the stack.


https://github.com/llvm/llvm-project/pull/83280