add mlir python bindings poc for qasm-to-qco pipeline

[ibishal]

Description

Adds Python bindings for the MQT compiler collection, exposing the full (py:qasm) to (mlir:qc) to (mlir:qco) pipeline from Python.

tested with a 2-qubit Bell circuit as input and the output is the full QCO dialect IR with value semantics.

  from mqt.core.mlir import qasm_to_qco

  result = qasm_to_qco("""
  OPENQASM 2.0;
  include "qelib1.inc";
  qreg q[2];
  h q[0];
  cx q[0], q[1];
  """)
  print(result)

 module {
    func.func @main() -> i64 attributes {passthrough = ["entry_point"]} {
      %c0_i64 = arith.constant 0 : i64
      %c1 = arith.constant 1 : index
      %c0 = arith.constant 0 : index
      %c2 = arith.constant 2 : index
      %0 = qtensor.alloc(%c2) : tensor<2x!qco.qubit>
      %out_tensor, %result = qtensor.extract %0[%c0] : tensor<2x!qco.qubit>
      %out_tensor_0, %result_1 = qtensor.extract %out_tensor[%c1] : tensor<2x!qco.qubit>
      %1 = qco.h %result : !qco.qubit -> !qco.qubit
      %controls_out, %targets_out = qco.ctrl(%1) targets (%arg0 = %result_1) {
        %4 = qco.x %arg0 : !qco.qubit -> !qco.qubit
        qco.yield %4 : !qco.qubit
      } : ({!qco.qubit}, {!qco.qubit}) -> ({!qco.qubit}, {!qco.qubit})
      %2 = qtensor.insert %controls_out into %out_tensor_0[%c0] : tensor<2x!qco.qubit>
      %3 = qtensor.insert %targets_out into %2[%c1] : tensor<2x!qco.qubit>
      qtensor.dealloc %3 : tensor<2x!qco.qubit>
      return %c0_i64 : i64
    }
  }

Fixes #1693

Checklist

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✅ All modified and coverable lines are covered by tests.

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[denialhaag]

Thanks for this first draft for adding Python bindings to mqt-cc, @ibishal! 🙂

This PR will require some more input from you before it is merge-ready. You can find some more details in the comments below.

In addition to the comments below, please ensure the implementation is tested in Python. The tests should live here: https://github.com/munich-quantum-toolkit/core/tree/main/test/python. This will ensure that the tests are also run in our CI. For this to work, BUILD_MQT_CORE_MLIR will have to be enabled here:

core/pyproject.toml

Lines 132 to 136 in 946116d

	[tool.scikit-build.cmake.define]
	BUILD_MQT_CORE_BINDINGS = "ON"
	BUILD_MQT_CORE_TESTS = "OFF"
	BUILD_MQT_CORE_SHARED_LIBS = "ON"
	BUILD_MQT_CORE_MLIR = "OFF"

[denialhaag]

It would be nice to structure this more like https://github.com/llvm/llvm-project/tree/main/mlir/include/mlir/CAPI.

[denialhaag]

It would be nice to structure this more like https://github.com/llvm/llvm-project/tree/main/mlir/lib/CAPI.

[denialhaag]

The bindings should live in https://github.com/munich-quantum-toolkit/core/tree/main/bindings.

[denialhaag]

This does not need to be committed. We are already testing the C++ implementation in https://github.com/munich-quantum-toolkit/core/tree/main/mlir/unittests.

[denialhaag]

It would be nice to extend this. All dialects, passes, and conversions should be accessible. It would also be nice to provide a compile_program() function that accepts an OpenQASM program and pushes it through the entire pipeline (see the steps in CompilerPipeline.cpp).

[denialhaag]

BUILD_MQT_CORE_MLIR_PYTHON should be enabled automatically if BUILD_MQT_CORE_MLIR and BUILD_MQT_CORE_BINDINGS are both enabled.

[burgholzer]

I would even argue there may be no need for a separate option. Whenever MLIR is enabled and the bindings are as well, this should be built.