[mlir][llvm] Add assert in CallOp builder (#76240)

This commit adds an assert in one of the CallOp builders to ensure it is not use to create an indirect call. Otherwise, the callee type would include the callee pointer type which is handed in as first argument.

Author: gitoleg

mlir/lib/Dialect/LLVMIR/IR/LLVMDialect.cpp

@@ -908,6 +908,7 @@ void CallOp::build(OpBuilder &builder, OperationState &state, TypeRange results,
 
 void CallOp::build(OpBuilder &builder, OperationState &state, TypeRange results,
                    FlatSymbolRefAttr callee, ValueRange args) {
+  assert(callee && "expected non-null callee in direct call builder");
   build(builder, state, results,
         TypeAttr::get(getLLVMFuncType(builder.getContext(), results, args)),
         callee, args, /*fastmathFlags=*/nullptr, /*branch_weights=*/nullptr,