ASAP Bottom-Up Analysis Tools
This toolset consists of a set of tools based on bottom-up analysis
developed in the
project and running in Ciao Prolog.
Bottom-up analysis has an elegant semantic basis based on the
declarative semantics of logic programs, straightforward implementation,
and flexible application. In addition, goal-directed or top-down
analyses can be simulated through the use of query-answer
transformations, of which the so-called "magic set" method is one.
These transformations can also serve to increase precision with
respect to bottom-up analysis. A toolkit of bottom-up analysis
tools and query-answer transformations has been built up. Efficient
algorithms for bottom-up analysis are at the heart of the toolkit.
A systematic method for implementing analyses using the tools is
The method is based on (i) abstract compilation of a program into
a "domain program", (ii) computation of (an approximation to) the
model of the domain program, and (iii) use of various query-answer
transformations to simulate goal-directed analysis and improve
precision. Stages (ii) and (iii) can also be used directly on the
original program in some applications. If the domain program has a
finite model, then a precise model can be computed in step (ii).
If the model is infinite or very large, methods of approximation
including regular approximation and others can be used.
Abstract compilation can be achieved very flexibly, based on the
construction of pre-interpretations based on arbitrary regular
Bottom-Up Analysis Tools
The main tools in BU are:
These tools are built from basic operations and components;
the main ones are as follows.
The purpose of the PolyTypes tool is to compute a
well-typing for a given module, namely, a set of type
rules together with a type signature for each module
predicate. A well-typing is interpreted in the
usual sense of Hindley-Milner types. The types
generated by PolyTypes are for example accepted
by the type checker for Mercury, a typed logic programming
The NFTA (Nondeterministic Finite Tree Automata)
tool computes a regular approximation of a
given program and uses this to detect useless
clauses. The tool computes descriptions of the sets
of terms that can occur in the heads of clauses in
computations of the program, as non-deterministic
regular tree grammars (or NFTAs). These are
both more complex and more accurate than classical
regular approximations which compute (topdown)
deterministic regular tree approximations.
The purpose of the Domain Model tool is to compute
an abstract model of a program over a finite
set of values such as types and modes. The abstraction
is determined by an arbitrary set of regular
- An implementation of the least model computation, which is the
least fixed point of the T_P function.
- Abstraction of a program with respect to a pre-interpretation.
- Derivation of a pre-interpretation by converting a non-deterministic
finite tree automaton (NFTA) to a deterministic finite tree automaton
- Backwards analysis transformation.
- Query answer transformations, enabling top-down analysis to be
handled in a bottom-up framework.
- Domain program transformation, enabling a program to be interpreted
over any pre-interpretation.
Download a tarfile
containing the Prolog sources. Then consult the README file which
contains a mini-manual.