Questions about Tai-e's APIs and implementations of callgraphs

[jjppp]

📝 Overall Description

API design

I currently noticed that CallGraph provides two different APIs with the same default implementation, CallGraph.getCalleesOfM() and CallGraph.getSuccsOf():

Tai-e/src/main/java/pascal/taie/analysis/graph/callgraph/AbstractCallGraph.java

Lines 71 to 75 in 21118b5

	public Set<Method> getCalleesOfM(Method caller) {
	return callSitesIn(caller)
	.flatMap(cs -> getCalleesOf(cs).stream())
	.collect(Collectors.toUnmodifiableSet());
	}

Tai-e/src/main/java/pascal/taie/analysis/graph/callgraph/AbstractCallGraph.java

Lines 155 to 159 in 21118b5

	public Set<Method> getSuccsOf(Method node) {
	return callSitesIn(node)
	.flatMap(cs -> getCalleesOf(cs).stream())
	.collect(Collectors.toUnmodifiableSet());
	}

The getSuccsOf seems straightforward to me, but the getCalleesOfM takes me a while to realize its meaning.
My question: Is this a deliberate design choice? What is the rationale behind this?

Mutable vs Immutable

The callgraphs seem to be mutable by design, i.e., by allowing adding nodes and edges to the callgraphs. This makes several callgraph related operations inefficient, such as querying the successors and predecessors of a node, where caching the results might be difficult.

However, many applications do not actually modify the callgraph (e.g., traversing the callgraphs when computing SCCs). Is there any chance that Tai-e will introduce ImmutableCallGraph or something like that?

🎯 Expected Behavior

Just out of curiosity

🐛 Current Behavior

Just out of curiosity

🔄 Reproducible Example

No response

⚙️ Tai-e Arguments

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🔍 Click here to see Tai-e Analysis Plan

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📜 Tai-e Log

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ℹ️ Additional Information

No response

[zhangt2333]

My question: Is this a deliberate design choice? What is the rationale behind this?

These two methods come from different interfaces:

• pascal.taie.analysis.graph.callgraph.CallGraph#getCalleesOfM
• pascal.taie.util.graph.Graph#getSuccsOf

CallGraph provides another interface with identical functionality, likely because getCalleesOfM has more specific semantics. BTW, obviously, one of the two can simply call the other to reuse code.

Is there any chance that Tai-e will introduce ImmutableCallGraph or something like that?

I agree, maybe this is an opportunity to bring it up.