This patch adds logic in the InputOutputTestAction frontend action for
reading input from stdin. Without this patch the following fails:
- flang-new -fc1 -test-io -
The implementation of InputOutputTestAction is cleaned-up and a test
for reading from stdin is added.
Note that there's a difference between -test-io and e.g. -E in terms
of file I/O. The frontend action for the former handles all file I/O on
it's own. Conversely, the action corresponding to -E relies on the
prescanner API to handle this.
Currently we can't test reading from stdin for flang-new -. In this
case libclangDriver assumes -x -c. This in turn leads to `flang-new
-cc1`, which is not supported.
Depends on: D95464