[TYPES] Paper: Polymorphic Bytecode: Compositional Compilation for Java-like Languages

[Davide Ancona]

Dear all,

we would like to announce the following technical report available at

  ftp://ftp.disi.unige.it/pub/person/AnconaD/PBCCJL.pdf

Comments are welcome.

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Polymorphic Bytecode: Compositional Compilation for Java-like Languages

      D. Ancona, F. Damiani, S. Drossopoulou, and E. Zucca


We define compositional compilation to be the
ability to typecheck source code fragments in isolation,
generate corresponding binaries, and link  together fragments
whose mutual assumptions are satisfied, without reinspecting the
code. Even though compositional compilation is a highly desirable
feature,
in Java-like languages  it can hardly be achieved. This is due to
the fact that the bytecode generated for a fragment (say, a class)
is not uniquely determined by its source code, but depends on the
compilation context.

In this paper, we propose
a way to obtain compositional compilation for Java, by introducing
a polymorphic form of bytecode containing type variables
(ranging over class names) and equipped with a set of constraints
involving type variables. Thus,
polymorphic bytecode provides a representation for all the
(standard Java) bytecode that can be obtained by
replacing type variables with class names satisfying the associated
constraints.

We illustrate our proposal by developing a type inference and a
linking algorithm for a small subset of Java. The type inference
algorithm compiles a class in isolation generating the
corresponding polymorphic bytecode fragment with the needed
constraints on the classes it depends on. The linking algorithm
takes a collection of polymorphic bytecode fragments, checks their
mutual consistency, and possibly simplifies and specializes them. In
particular, when a self-contained collection of fragments is taken,
linking either fails, or produces standard Java bytecode (which
is the same as the one which would have been produced by
standard Java compilation of all fragments together).

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Best regards,

	Davide Ancona
         Ferruccio Damiani
         Sophia Drossopoulou
         Elena Zucca

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Davide Ancona         | phone:  ++39 (010) 353 6636
DISI                  | fax:    ++39 (010) 353 6699
Universita' di Genova | e-mail: davide at disi.unige.it
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