BinderDavid authored Jun 17, 2024 and Marge Bot committed Jun 18, 2024

This commit introduces the RTS flag `--read-tix-file=<yes|no>` which
controls whether a preexisting .tix file is read in at the beginning
of a program run. The default is currently `--read-tix-file=yes` but
will change to `--read-tix-file=no` in a future release of GHC. For
this reason, whenever a .tix file is read in a warning is emitted to
stderr. This warning can be silenced by explicitly passing the
`--read-tix-file=yes` option. Details can be found in the GHC proposal
cited below.

Users can query whether this flag has been used with the help of the
module `GHC.RTS.Flags`. A new field `readTixFile` was added to the
record `HpcFlags`.

These changes have been discussed and approved in
- GHC proposal 612: https://github.com/ghc-proposals/ghc-proposals/pull/612
- CLC proposal 276: https://github.com/haskell/core-libraries-committee/issues/276