This CL introduces an alternative way to calculate scopes for
expression evaluations. Currently the previous method is kept as well.
What this does is that it:
* Finds all nodes that match the offset and uri. (Ideally there's only
one, but that's not always the case --- it's the case for less than
60% of cases in the test added actually).
* Calculate the scope along the way.
* Return the scopes of all the found nodes that offset.
A test that asks for ~all file offsets in the dill files in the sdk and
compares the result with the scope the binary serialization computes is
added.
A single point can't always be found (for all dills in the sdk
only ~58.93% returns a single result), but for each query the wanted
scope is among the results returned.
For the non-outline dills in the sdk, between ~87.93% and ~94.52% of
the results are either a single result or multiple results with the
same actual scope in all of them.
Note that the test asks for ~all offsets, not just "debuggable" or
"stopable" offsets (which will likely vary depending on the vm/web
backend etc) --- likely the percentage will be higher for those points
though.
When this returns multiple results one can likely be picked by the
client based on information it has about names of variables in scope
etc.
Note that the test is rather slow, on my machine with the platforms
available there it makes 3,908,181 queries in ~3.5 minutes.
(Which corresponds to roughly 18,610 per second or under 0.06 ms per
query on average though, so it doesn't seem like a concert for actually
using it.)
Change-Id: I40b5360fcd935c70629543737e89a787de36ca16
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/332204
Reviewed-by: Johnni Winther <johnniwinther@google.com>
Commit-Queue: Jens Johansen <jensj@google.com>
Jens Johansen