With the type inference pass now being able to handle RT operations
and multiple functions, the restriction disallowing data-flow
parallelization when choosing the dag-multi optimization strategy can
be lifted. Remove the check and bail out in `CompilerEngine.cpp`.
This adds support for the operations `RT.await_future`,
`RT.build_return_ptr_placeholder`, `RT.create_async_task`,
`RT.deref_return_ptr_placeholder`,
`RT.deref_work_function_argument_ptr_placeholder`,
`RT.make_ready_future`, `RT.register_task_work_function`, and
`RT.work_function_return`, the RT types `RT.ptr` and `RT.future`, as
well as the auxiliary operation `arith.select`.
The type inference pass currently only supports a single function as
it is unable to infer types across function boundaries. This commit
adds support for multiple functions and tracks types across
`func.func`, `func.call` and function `constant` operations.
A function may be referenced at multiple sites, including at locations
that have not been visited by the rewriter when the function itself is
rewritten. By using `IRRewriter::replaceOp` after rewriting a
function, the function is erased immediately, which may cause the
rewriting to fail due to remaining uses of the function.
Defering the erasure of functions to the end of the entire rewriting
process ensures that all uses of the original functions have been
updated to the rewritten functions.
Operations with regions containing multiple blocks are currently not
handled correctly, since the list of successors of an operation is not
updated with rewritten blocks when the operation is
rewritten. Furthermore, functions were assumed to have only a single
block.
This change supports operations with multiple blocks by fixing the
issues above.
Updates of the types inferred for the values related to an operation
only propagate correctly to the operation if there is a direct
producer-consumer relationship or an indirect producer-consumer
relationship via some additional mechanism (e.g., region
successors). However, this is not sufficient to ensure updates of
values and operations that are related otherwise.
This change explicitly models the dependencies between related values
and an operation via `DataFlowAnalysis::addDependency` in order to
guarantee that all updates of the types of values are propagated to
all operations that the type resolver has designated as related
operations.
Furthermore, all operations are visited once initially in order to
guarantee that updates propagate to operations, for which the dataflow
framework does not invoke `visitOperation`.
This delegates the enumeration of values related to an operation to
the class `TypeResolver`. This allows for the customization of this
process via a class inheriting `TypeResolver`.
