[MooreToCore] Emit targeted diagnostics for unsupported module port types (fixes #9572)

[m2kar]

Summary

Fix assertion failure and emit precise diagnostic when moore.module has unsupported port types. Previously, typeConverter.convertType() could return nullptr for unsupported types (e.g., !moore.queue<i32, 10>, !moore.string), causing either a crash or an unhelpful "failed to legalize" error.

Fixes #9572

Root Cause

File: lib/Conversion/MooreToCore/MooreToCore.cpp
Function: getModulePortInfo()

The function did not validate the result of typeConverter.convertType():

Type portTy = typeConverter.convertType(port.type);  // May return nullptr
ports.push_back(hw::PortInfo({{port.name, portTy, port.dir}, ...}));  // Stores invalid type
return hw::ModulePortInfo(ports);  // Constructor calls sanitizeInOut() → dyn_cast assertion

When conversion fails, the invalid Type is passed to ModulePortInfo constructor, triggering an assertion in sanitizeInOut().

Fix

Code Changes

lib/Conversion/MooreToCore/MooreToCore.cpp:231-285

1. Changed return type to FailureOr<hw::ModulePortInfo>:

-static hw::ModulePortInfo getModulePortInfo(const TypeConverter &typeConverter,
-                                            SVModuleOp op) {
+static FailureOr<hw::ModulePortInfo>
+getModulePortInfo(const TypeConverter &typeConverter, SVModuleOp op) {

2. Added validation after type conversion:

Type portTy = typeConverter.convertType(port.type);
+if (!portTy) {
+  return op.emitOpError("port '")
+         << port.name << "' has unsupported type " << port.type
+         << " that cannot be converted to hardware type";
+}

3. Updated caller to handle failure:

+auto portInfo = getModulePortInfo(*typeConverter, op);
+if (failed(portInfo))
+  return failure();
 auto hwModuleOp = hw::HWModuleOp::create(rewriter, op.getLoc(), op.getSymNameAttr(),
-                                           getModulePortInfo(*typeConverter, op));
+                                           *portInfo);

Test Coverage

test/Conversion/MooreToCore/errors.mlir

Added two test cases:

// Test 1: Single unsupported port
moore.module @UnsupportedInputPortType(in %queue_port : !moore.queue<i32, 10>) {
  moore.output
}
// expected-error: port 'queue_port' has unsupported type '!moore.queue<i32, 10>'

// Test 2: Mixed supported and unsupported ports
moore.module @MixedPortsWithUnsupported(in %valid : !moore.l1,
                                        in %data : !moore.queue<i32, 10>,
                                        out out : !moore.l1) {
  moore.output %valid : !moore.l1
}
// expected-error: port 'data' has unsupported type '!moore.queue<i32, 10>'

Behavior Changes

Aspect	Before	After
Error message	failed to legalize operation 'moore.module'	port '<name>' has unsupported type '<type>' that cannot be converted to hardware type
Crash on empty type	Possible assertion failure	Graceful failure with diagnostic
Debugging effort	High (inspect IR manually)	Low (error identifies problem)

Fixes #9572