DynSem is a domain-specific language for concise specification of the dynamic semantics of programming languages, aimed at rapid experimentation and evolution of language designs. To maintain a short definition-to-execution cycle, DynSem specifications are meta-interpreted. Meta-interpretation introduces runtime overhead that is difficult to remove by using interpreter optimization frameworks such as the Truffle/Graal Java tools; previous work has shown order-of-magnitude improvements from applying Truffle/Graal to a meta-interpreter, but this is still far slower than what can be achieved with a language-specific interpreter. In this paper, we show how specifying the meta-interpreter using scope graphs, which encapsulate static name binding and resolution information, produces much better optimization results from Truffle/Graal. Furthermore, we identify that JIT compilation is hindered by large numbers of calls between small polymorphic rules and we introduce rule cloning to derive larger monomorphic rules at run time as a countermeasure. Our contributions improve the performance of DynSem-derived interpreters to within an order of magnitude of a handwritten language-specific interpreter.

Semantic specifications do not make a systematic connection between the names and scopes in the static structure of a program and memory layout, and access during its execution. In this paper we introduce a systematic approach to the alignment of names in static semantics and memory in dynamic semantics, building on the scope graph framework for name resolution. We develop a uniform memory model consisting of frames that instantiate the scopes in the scope graph of a program. This provides a language-independent correspondence between static scopes and run-time memory layout, and between static resolution paths and run-time memory access paths. The approach scales to a range of binding features, supports straightforward type soundness proofs, and provides the basis for a language-independent specification of sound reachability-based garbage collection.

We describe a language-independent theory for name binding and resolution, suitable for programming languages with complex scoping rules including both lexical scoping and modules. We formulate name resolution as a two-stage problem. First a language-independent scope graph is constructed using language-specific rules from an abstract syntax tree. Then references in the scope graph are resolved to corresponding declarations using a language-independent resolution process. We introduce a resolution calculus as a concise, declarative, and language-independent specification of name resolution. We develop a resolution algorithm that is sound and complete with respect to the calculus. Based on the resolution calculus we develop language-independent definitions of α-equivalence and rename refactoring. We illustrate the approach using a small example language with modules. In addition, we show how our approach provides a model for a range of name binding patterns in existing languages.