Improved property edges

[oxisto]

TL;DR

This PR adds major improvements to property edges. We got rid of the Properties map and replaced them with individual Kotlin properties. Furthermore lists of edges are now dedicated container classes with magic.

Introduction of new specific edge classes

Next to the Dataflow edge class, which already exists, we added new edge classes. The PropertyEdge class itself is now abstract and thus no "generic" property edges (without any properties) can be created. There were a few uses of these kind of edges, this PR reverts them back to regular node lists (until we decide that this edge actually needs properties).

Usage

This edge class denotes the usage of a declaration in a reference.

Invoke

Invocation of a function declaration by a call expression.

AstEdge

Part of the AST.

TemplateArgument

AST edge for template invocation arguments.

EvaluationOrder

Part of the EOG.

ControlDependence

Part of the CDG.

Conversion of properties in Properties map to individual properties

This is basically the consequence of the above:

• INDEX: index to Edge
• NAME: name to Edge
• DEPENDENCE: dependence to Edge
• UNREACHABLE: unreachable to EvaluationOrder
• BRANCH: branch to EvaluationOrder
• BRANCH: branches to ControlDependence
• INSTANTIATION: instantiation to TemplateArgument

Simplified creation of edges

Previously we had a lot of addXXX wrapper functions around property edges that took care of things like "mirroring" prev/next as well as inserting indices. This is all now done automagically by appropriate containers of property edges (and under the PropertyEdgeCollection interface under the hood.

This makes it easy to add new edges to the collection based on "target" nodes and it also supports setting appropriate properties using a builder pattern.

node1.nextEOGEdges.add(node2) {
  branch = false
  unreachable = true
}

For all "mirrored" properties, this will also add the edge to the corresponding mirror property (next vs. prev). In order to use this feature the mirror property needs to be specified.

class Node /* ... */ {
  var nextDFGEdges: Dataflows<Node> = Dataflows<Node>(this, Node::prevDFGEdges, outgoing = true)
  var prevDFGEdges: Dataflows<Node> = Dataflows<Node>(this, Node::nextDFGEdges, outgoing = false)
}

node1.nextDFGEdges.add(node2)
// node2 will also now have node1 in its prevDFGEdges

Open Issues

• Use mirror collection in EOG nodes
• Remove all remaining add/remove functions
• Implement preRemove hook for removal functions
• Final cleanups
• Rename PropertyEdge to Edge to be more consistent with Node?
• Decide on the type returned by unwrapping (List vs. MutableList vs UnwrappedEdgeList)

[sonarcloud]

Quality Gate passed

Issues
14 New issues
0 Accepted issues

Measures
0 Security Hotspots
76.7% Coverage on New Code
0.1% Duplication on New Code

See analysis details on SonarCloud