This checks explicitly for unresolved objects while sorting and provides an
explicit error for them. For example, this will catch externs that have no
concrete resolution.
This previously fell all the way through to the unreachable! block. The old
POC implementation was catching unresolved objects, albeit with a debug
error.
This will be used for the next commit, but this change has been isolated
both because it distracts from the implementation change in the next commit,
and because it cleans up the code by removing the need for a type parameter
on `AsgError`.
Note that the sort test cases now use `unwrap` instead of having
`{,Sortable}AsgError` support one or the other---this is because that does
not currently happen in practice, and there is not supposed to be a
hierarchy; they are siblings (though perhaps their name may imply otherwise).
The only reason this function was a method of `BaseAsg` was because of
`self.graph`, which is accessible within the scope of this
module. `check_cycles` is logically associated with `SortableAsg`, and so
should exist alongside it (though it can't exist as an associated function
of that trait).
We want to be able to build a representation of the dependency graph so
we can easily inspect it.
We do not want to make GraphML by default. It is better to use a tool.
We use "petgraph-graphml".
The `Debug` bound is inconvenient and requires propagation to any types that
use it. Further, it's really awkward having `Display` depend on `Debug`; if
we want to render a useful display here, we can write one.
To be clear: IndexType implements Debug.
For now, this is pretty-printed by another part of the code, which we don't
want to implement in `Display` because it requires looking things up from
the graph.
This is an awkward system that I'd like to remove at some point. It adds
complexity. For the meantime, overrides have been arbitrarily restricted to
a single override (no override-override). But it's needed being until we
rework maps and can handle the illusion of overrides using the template
system.
Benchmark performance for this method is still substantially slower. And
oddly, this nearly doubled the speed of the other two calls (granted, at
that speed, it doesn't matter).
All of these refactoring commits to arrive at this one final change: the
ability to store the source location for externs so that we can report on
what package is expecting an identifier to be defined.
Phew. Goodnight.
This undoes work I did earlier today...but now we'll be able to support a
Source on an extern.
There is duplicate code between `BaseAsg::declare{,_extern}` that will be
resolved in an upcoming commit. Upcoming commits will also simplify
terminology and clean up methods on ObjectState.
There is some duplication here with `declare` that will be cleared up in a
following commit. Reintroducing this method is necessary so that Source can
be used to represent the source location of the extern itself; it's
currently None to indicate an extern in `declare`.
This is the first step in a more incremental refactoring that previous
commits to undo the optional Source in `ObjectState::ident`. This provides
an explicit transition to an extern, with the intent of requiring an initial
missing state. This will simplify logic on the ASG.
Note that the Source provided to this new method is not yet used. That too
will come in a following commit and will represent the source of the defined
extern rather than the concrete identifier.
This properly verifies extern types, and cleans up Asg's API a little so
that externs aren't handled much differently than other declarations.
With that said, after making src optional, I realized that we will indeed
want source information for externs themselves so we can direct the user to
what package is expecting that symbol (as the old linker does). So this
approach will not work, and I'll have to undo some of those changes.
This is essential to clarify what exactly the different object types
represent with the new generic abstractions. For example, we will have
expressions as an object type.
There's a lot here to make the object stored on the `Asg` generic. This
introduces `ObjectState` for state transitions and `ObjectData` for pure
data retrieval. This will allow not only for mocking, but will be useful to
enforce compile-time restrictions on the type of objects expected by the
linker vs. the compiler (e.g. the linker will not have expressions).
This commit intentionally leaves the corresponding tests in their original
location to prove that the functionality has not changed; they'll be moved
in a future commit.
This also leaves the names as "Object" to reduce the number the cognative
overhead of this commit. It will be renamed to something like "IdentObject"
in the near future to clarify the intent of the current object type and to
open the way for expressions and a type that marries both of them in the
future.
Once all of this is done, we'll finally be able to make changes to the
compatibility logic in state transitions to implement extern compatibility
checks during resolution.
DEV-7087
The next commit will generalize this further. This moves logic out of
BaseAsg so that we can implement more sophisticated transitions for
compatability checks.
The logic is still tested as part of BaseAsg; the next commit will change
that as it's generalized further.
* tamer/src/ir/asg/base.rs: Extract object transitions.
* tamer/src/ir/asg/graph.rs (AsgError)[IncompatibleIdent]: New variant.
(From<TransitionError> for AsgError): Basic type translation.
* tamer/src/ir/asg/object.rs (TransitionResult): New type.
(impl Object): Transition methods.
(TransitionError): New enum.
This variant is unnecessary, as it was used only by the indexer to represent
the absence of a node, for which was can simply use `None` in the containing
`Option`.
* tamer/Cargo.toml: Add `lazy_static`.
* tamer/Cargo.lock: Update.
* tamer/src/ir/asg/base.rs (with_capacity): Use `None` in place of
`Some(Object::Empty)`.
* tamer/src/ir/asg/object.rs: Adjust state machine graphic.
(Empty): Remove variant.
(Missing): Remove reference to variance.
* tamer/src/lib.rs: Import `lazy_static` for test builds.
* tamer/obj/xmle/writer/writer.rs (Section::iter): Remove `Object::Empty`
from documentation.
(test::): Remove references to `Object::Missing`. `lazy_static!` used
here.
* tamer/obj/xmle/writer/xmle.rs (test::write_section_catch_missing): Replace
reference to `Object::Missing`.
This still isn't comprehensive. Further, it won't be able to be, because
we'd have to rely on Petgraph implementation details: there are potentially
many acceptable orderings for a given graph.
Create a trait that sorts a graph into `Sections` that can then be used
as an IR. The `BaseAsg` should implement the trait using what was
originally in the POC.
If we cannot set a fragment, we need to display the error to the user.
We are currently ignoring "___head", "___tail", and objects that are
both virtual and overridden. Those will be corrected in with future
changes.
This begins to introduce the ASG, backed by Petgraph. The API will continue
to evolve, and Petgraph will likely be encapsulated so that our
implementation can vary independently from it (or even remove it in the
future).
Mike Gerwitz
Joseph Frazer