Constraint Solver¶

The constraint solver subsystem is aimed to provide the possibility to automatically generate test cases based on specified constraints. A constraint is represented by a set of limitations for input values. The solver finds values of input variables which will violate the limitations if there are any.

The subsystem uses a third-party SMT solver as an engine (in the current version, we use the Z3 solver by Microsoft Research). SMT solvers use a special functional language to specify constraints. The subsystem generates constructions in the SMT language and uses the engine to process them and produce the results (find values of unknown input variables).

We use language-independent syntax trees to represent constraints. These trees then are processed to generate a representation that can be understood by a particular SMT solver. The syntax tree contains the following node types:

1. Constraint. This is the root node of the tree. It holds the list of unknown variables and the list of limitations for these variables.
2. Formula. Represents a limitation expression. Can be combined with other limitations to build a more complex limitation (by applying a logic OR, AND or NOT to it).

Constraint Solver Library¶

The ru.ispras.microtesk.constraints package includes the following sub-packages:

Language-independent syntax tree¶

База данных ограничений¶

База данных ограничений строится автоматически в результате анализа формализованных спецификаций системы команд микропроцессора, выполненной на одном из ADL-языков (например, nML). Некоторые ситуации могут описываться вручную и добавляться в базу данных ограничений.