Snapshots which contain code are compiled with a particular null-safety
mode and it is not possible to change their mode at run time.
When running from such snapshot, VM now reads null-safety mode from
the snapshot if it is not specified at the command line.
This avoids the need for embedders to pass null-safety flag
used during snapshot generation also to the runtime, similarly to
other VM flags listed in VM_GLOBAL_FLAG_LIST (such as use_bare_instructions).
In addition, error for incompatibility of kernel libraries with
current null-safety mode is changed from ReportError (which attempts
to throw an exception) to a FATAL, because throwing an exception
crashes when bootstrapping from a kernel file.
Change-Id: I93a791825c25c2da4e33634f1c71736c17928fea
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/146460
Reviewed-by: Régis Crelier <regis@google.com>
Commit-Queue: Alexander Markov <alexmarkov@google.com>
Alexander Markov
16fb650d25