Ensure the stream flushed to the string before acquiring the mutext.
No need to flush the output stream, the goal of the mutex is to sync
ahead before content is added to the stream.
This will match the locations attached to the IRunits passed in as context
with an action.
This is a recommit of d09c80515d0e after fixing the test on Windows.
Differential Revision: https://reviews.llvm.org/D144815
IRUnit is defined as:
using IRUnit = PointerUnion<Operation *, Region *, Block *, Value>;
The tracing::Action is extended to take an ArrayRef<IRUnit> as context to
describe an Action. It is demonstrated in the "ActionLogging" observer.
Reviewed By: rriddle, Mogball
Differential Revision: https://reviews.llvm.org/D144814
Integrate the `tracing::ExecutionContext()` into mlir-opt with a new
--log-action-to=<file> option to demonstrate the feature.
Reviewed By: rriddle
Differential Revision: https://reviews.llvm.org/D144813
