Compiling concurrency correctly: cutting out the middle man

The standard approach to proving compiler correctness for concurrent languages requires the use of multiple translations into an intermediate process calculus. We present a simpler approach that avoids the need for such an intermediate language, using a new method that allows us to directly establish a bisimulation between the source and target languages. We illustrate the technique on two small languages, using the Agda system to present and formally verify our compiler correctness proofs

Decoding Choice Encodings

We study two encodings of the asynchronous pi-calculus with input-guarded choice into its choice-free fragment. One encoding is divergence-free, but refines the atomic commitment of choice into gradual commitment. The other preserves atomicity, but introduces divergence. The divergent encoding is fully abstract with respect to weak bisimulation, but the more natural divergence-free encoding is not. Instead, we show that it is fully abstract with respect to coupled simulation, a slightly coarser - but still coinductively defined - equivalence that does not enforce bisimilarity of internal branching decisions. The correctness proofs for the two choice encodings introduce a novel proof technique exploiting the properties of explicit decodings from translations to source terms

Compiler Correctness for Concurrent Languages

. This paper extends previous work in compiler derivation and verification to languages with true-concurrency semantics. We extend the -calculus to model process-centered concurrent computation, and give the semantics of a small language in terms of this calculus. We then define a target abstract machine whose states have denotations in the same calculus. We prove the correctness of a compiler for our language: the denotation of the compiled code is shown to be strongly bisimilar to the denotation of the source program, and the abstract machine running the compiled code is shown to be branching-bisimilar to the source program's denotation. 1 Introduction Our original goal was to verify a compiler for Linda [8], using that language as a representative of modern concurrent language design. Upon searching the literature, we found a vast amount of work on models of concurrency, but little that was obviously applicable to compiler derivation and verification. Accordingly we decided to tac..