QIR Base profile Compliant QASM Conversions

[feelerx]

Summary of changes

This PR addresses critical compliance gaps between the current qasm3_to_qir implementation and the QIR Base Profile specification. The changes ensure proper measurement state tracking, correct function usage, and adherence to Base Profile restrictions.
Profile Structure
Each profile is defined as a JSON file with the following structure:

{
  "profile_name": "ProfileName",
  "version": "1.0.0",
  "description": "Profile description",
  "capabilities": {
    "feature_name": {
      "enabled": true,
      "description": "Feature description",
      "additional_options": "..."
    }
  },
  "required_functions": {
    "quantum_intrinsics": ["function_list"],
    "runtime_functions": ["function_list"]
  },
  "restrictions": {
    "restriction_category": {
      "setting": "value"
    }
  },
  "validation_rules": {
    "rule_category": {
      "rule_name": "rule_value"
    }
  },
  "compliance_checks": [
    {
      "rule_id": "PROFILE_001",
      "description": "Rule description",
      "severity": "error|warning|info",
      "check_type": "check_category"
    }
  ]
}

Compliance Issues Identified

1. Missing Qubit Measurement State Tracking (CRITICAL)
   Issue: The Base Profile requires tracking which qubits have been measured to enforce the restriction that qubits cannot be used after measurement without reset.
   Current State: No measurement tracking implemented
   Current implementation lacks:
   self._measured_qubits: dict[int, bool] = {}
   Base Profile Requirement:

• BASE_004: "Must not use qubits after measurement without reset"
• qubit_usage.track_measurement_state: true
• qubit_usage.allow_post_measurement_operations: false

2. Inconsistent Function Usage Patterns (HIGH)
   Issue: Current implementation doesn't consistently enforce Base Profile function requirements.
   Base Profile Requirements:

• BASE_001: Uses pyqir._native.mz for measurements
• BASE_002: Uses pyqir._native.reset for qubit reset operations
• BASE_003: Uses pyqir._native.if_result for conditional branching
  Current State: Functions are used correctly but without explicit profile validation

3. Inadequate Post-Measurement Validation (MEDIUM)
   Issue: No validation to prevent quantum operations on measured qubits.
   Base Profile Restriction:

"qubit_reuse": {
  "enabled": false,
  "description": "Does not allow quantum operations on qubits after measurement"
}

4. Missing Reset State Management (MEDIUM)
   Issue: Reset operations don't properly clear measurement state tracking.
   Expected Behavior: Reset should clear the measured state of qubits to allow future operations.
   Changes Made

5. Added Measurement State Tracking

# In __init__
if self._profile.should_track_qubit_measurement():
    self._measured_qubits: dict[int, bool] = {}

# In _visit_measurement
if self._profile.should_track_qubit_measurement():
    qubit_id_result = pyqir.qubit_id(src_id)
    if qubit_id_result is not None:
        self._measured_qubits[qubit_id_result] = True

2. Implemented Qubit Use After Measurement Validation

def _check_qubit_use_after_measurement(self, qubit_ids: List[pyqir.Constant]) -> None:
    """Check qubit use after measurement based on profile capabilities."""
    if not self._profile.allow_qubit_use_after_measurement():
        for qubit_id in qubit_ids:
            qubit_id_result = pyqir.qubit_id(qubit_id)
            if qubit_id_result is not None and self._measured_qubits.get(qubit_id_result, False):
                raise_qasm3_error(
                    f"Base Profile violation: Cannot use qubit {qubit_id_result} after measurement"
                )

3. Added Reset State Management

# In _visit_reset
if self._profile.should_track_qubit_measurement():
    qubit_id_result = pyqir.qubit_id(qid)
    if qubit_id_result is not None:
        self._measured_qubits[qubit_id_result] = False

4. Enhanced Profile-Aware Gate Operations

# In _visit_basic_gate_operation
def _visit_basic_gate_operation(self, operation: qasm3_ast.QuantumGate) -> None:
    # ... existing code ...
    op_qubits = self._get_op_bits(operation)
    
    # Profile-aware qubit usage check
    self._check_qubit_use_after_measurement(op_qubits)
    # ... rest of implementation

5. Updated Profile Classes for Base Profile Compliance

class BaseProfile(Profile):
    def should_track_qubit_measurement(self) -> bool:
        return True  # Base profile requires measurement tracking
    
    def allow_qubit_use_after_measurement(self) -> bool:
        return False  # Base profile restriction

[codecov]

Codecov Report

Attention: Patch coverage is 83.33333% with 1 line in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
qbraid_qir/qasm3/visitor.py	80.00%	1 Missing ⚠️

📢 Thoughts on this report? Let us know!

[TheGupta2012]

@feelerx could you please resolve merge conflicts in this PR? I feel this has a lot of overlapping changes from the Adaptive PR

[TheGupta2012]

Also, better to rebase and apply changes on top of current main

[TheGupta2012]

Thanks @feelerx, lgtm! I think most changes were already completed in #225, I'll let @ryanhill1 take one final look before approving.

[ryanhill1]

LGTM