This commit contains several incremental improvements towards a clear
interface for lambdas:
- Unification of static and JIT compilation by using the static
compilation path of `CompilerEngine` within a new subclass
`JitCompilerEngine`.
- Clear ownership for compilation artefacts through
`CompilationContext`, making it impossible to destroy objects used
directly or indirectly before destruction of their users.
- Clear interface for lambdas generated by the compiler through
`JitCompilerEngine::Lambda` with a templated call operator,
encapsulating otherwise manual orchestration of `CompilerEngine`,
`JITLambda`, and `CompilerEngine::Argument`.
- Improved error handling through `llvm::Expected<T>` and proper
error checking following the conventions for `llvm::Expected<T>`
and `llvm::Error`.
Co-authored-by: youben11 <ayoub.benaissa@zama.ai>
