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arXiv · 1308.6810

Herding Cats - Modelling, simulation, testing, and data-mining for weak memory

Jade Alglave·Luc Maranget·Michael Tautschnig
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Abstract

We propose an axiomatic generic framework for modelling weak memory. We show how to instantiate this framework for SC, TSO, C++ restricted to release-acquire atomics, and Power. For Power, we compare our model to a preceding operational model in which we found a flaw. To do so, we define an operational model that we show equivalent to our axiomatic model. We also propose a model for ARM. Our testing on this architecture revealed a behaviour later acknowledged as a bug by ARM, and more recently 33 additional anomalies. We offer a new simulation tool, called herd, which allows the user to specify the model of his choice in a concise way. Given a specification of a model, the tool becomes a simulator for that model. The tool relies on an axiomatic description; this choice allows us to outperform all previous simulation tools. Additionally, we confirm that verification time is vastly improved, in the case of bounded model-checking. Finally, we put our models in perspective, in the light of empirical data obtained by analysing the C and C++ code of a Debian Linux distribution. We present our new analysis tool, called mole, which explores a piece of code to find the weak memory idioms that it uses.

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Jade Alglave, Luc Maranget, Michael Tautschnig. 2014-01-09. Herding Cats - Modelling, simulation, testing, and data-mining for weak memory. https://arxiv.org/abs/1308.6810

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