370 research outputs found
Second-Order Functions and Theorems in ACL2
SOFT ('Second-Order Functions and Theorems') is a tool to mimic second-order
functions and theorems in the first-order logic of ACL2. Second-order functions
are mimicked by first-order functions that reference explicitly designated
uninterpreted functions that mimic function variables. First-order theorems
over these second-order functions mimic second-order theorems universally
quantified over function variables. Instances of second-order functions and
theorems are systematically generated by replacing function variables with
functions. SOFT can be used to carry out program refinement inside ACL2, by
constructing a sequence of increasingly stronger second-order predicates over
one or more target functions: the sequence starts with a predicate that
specifies requirements for the target functions, and ends with a predicate that
provides executable definitions for the target functions.Comment: In Proceedings ACL2 2015, arXiv:1509.0552
Development of a Translator from LLVM to ACL2
In our current work a library of formally verified software components is to
be created, and assembled, using the Low-Level Virtual Machine (LLVM)
intermediate form, into subsystems whose top-level assurance relies on the
assurance of the individual components. We have thus undertaken a project to
build a translator from LLVM to the applicative subset of Common Lisp accepted
by the ACL2 theorem prover. Our translator produces executable ACL2 formal
models, allowing us to both prove theorems about the translated models as well
as validate those models by testing. The resulting models can be translated and
certified without user intervention, even for code with loops, thanks to the
use of the def::ung macro which allows us to defer the question of termination.
Initial measurements of concrete execution for translated LLVM functions
indicate that performance is nearly 2.4 million LLVM instructions per second on
a typical laptop computer. In this paper we overview the translation process
and illustrate the translator's capabilities by way of a concrete example,
including both a functional correctness theorem as well as a validation test
for that example.Comment: In Proceedings ACL2 2014, arXiv:1406.123
ACL2(ml):machine-learning for ACL2
ACL2(ml) is an extension for the Emacs interface of ACL2. This tool uses
machine-learning to help the ACL2 user during the proof-development. Namely,
ACL2(ml) gives hints to the user in the form of families of similar theorems,
and generates auxiliary lemmas automatically. In this paper, we present the two
most recent extensions for ACL2(ml). First, ACL2(ml) can suggest now families
of similar function definitions, in addition to the families of similar
theorems. Second, the lemma generation tool implemented in ACL2(ml) has been
improved with a method to generate preconditions using the guard mechanism of
ACL2. The user of ACL2(ml) can also invoke directly the latter extension to
obtain preconditions for his own conjectures.Comment: In Proceedings ACL2 2014, arXiv:1406.123
Enhancements to ACL2 in Versions 6.2, 6.3, and 6.4
We report on improvements to ACL2 made since the 2013 ACL2 Workshop.Comment: In Proceedings ACL2 2014, arXiv:1406.123
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