The code in `lib/CAPI/Support/CompilerEngine.cpp` invokes several
functions returning an `llvm::Expected<T>`. When those fail, the error
message retrieved from the error object the `llvm::Expected<T>`
instance is written to the standard error stream via
`mlir::zamalang::log_error()` and an exception with a more generic
error message is thrown.
This causes errors to show up on the standard error stream in tests
generating errors on purpose and checking them, e.g.:
```
tests/python/test_compiler_engine.py::test_compile_invalid[not
@main] Compilation failed: cannot find the function for generate
client parameters PASSED
```
This patch forwards the error message from an `llvm::Expected<T>`
instance in a runtime exception rather than writing it to the standard
error stream. Since exceptions are properly caught by the tests, no
errors show up during testing.
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>
