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Introduction
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Soot: a Java Optimization Framework

Latest version: 1.2.1 (January 29, 2001)


Need help using Soot? See the Soot tutorials.

Introduction top
Soot is a Java optimization framework. It provides three intermediate representations for analyzing and transforming Java bytecode:
  1. Baf: a streamlined representation of bytecode which is simple to manipulate.
  2. Jimple: a typed 3-address intermediate representation suitable for optimization.
  3. Grimp: an aggregated version of Jimple suitable for decompilation and code inspection.
Soot can be used as a stand alone tool to optimize or inspect class files, as well as a framework to develop optimizations or transformations on Java bytecode.

Soot is free software and is licensed under the GNU Library General Public License.


Release Status top

The Soot Framework is an evolving research project. Our goal is to produce a highly robust framework for optimizing Java which is easy to use.

The latest release is version 1.2.1, which fixes a few bugs from release 1.2.0. A big improvement is that the release 1.2.1 can accept .jar file in the --soot-class-path command option. Also Jasmin has been upgraded to 1.06-s9; which no longer depends on Soot. (Note that versions prior to 1.06-s8 also did not depend on Soot.)

The major new feature in 1.2.0 is support for classfile annotation (courtesy of Feng Qian and Patrice Pominville). There is also an improved typing system, due to Etienne Gagnon. Variable-Type Analysis was cleanly reimplemented by Felix Kwok and we have included it in our release of Soot for the first time. We also fixed a few bugs reported against version 1.0.0.

In the future, we will develop a mechanism to support whole-program analysis based on a program's call graph.


Improvements in version 1.2.1 top
The release 1.2.1 fixed the jar bug in older versions. Now Soot can accept `rt.jar' in the --soot-class-path command-line option.

Major improvements in version 1.2.0

This is a subset of changes in version 1.2.0; a more complete listing is in the CHANGES file.

1. An annotation framework was added to the project.
2. A new implementation of the typing system is included.
3. A clean implementation of VTA is finally included in Soot.


Download and Installation top
Get Soot from our software repository at http://www.sable.mcgill.ca/software.

To install it you must unjar(untar) it, and add the classes directories soot-1.2.1/soot/classes and soot-1.2.1/jasmin/classes to your CLASSPATH. To test your installation of Soot, try:

java soot.Main

for some options on processing classfiles. They are documented in more detail in the usage document.

Note that Soot requires at least JDK 1.2 (Java 2), as it uses Java Collections. We have experienced some problems with the sunwjit JIT compiler; we do not recommend the use of this JIT. In particular, common subexpression elimination has triggered JIT problems with sunwjit.


Compilation top
Soot is already compiled in the distribution. To recompile Soot, we recommend the use of the SootCompiler class in the main soot/src directory. However, we use make using the Makefile in the main soot directory. Note that in either case, jasmin must be in your classpath to compile Soot. Release 1.2.1 uses a new version of Jasmin, 1.06-s9, which has no dependence on Soot.

NOTE: The Jimple parser is generated by SableCC. It requires lexer.dat and parser.dat files to be in the classes directory; they are provided in the src directory. Also, Soot uses peephole optimization to improve the generated bytecode. This requires the peephole.dat file be copied to the classes directory. Both the provided Makefile and SootCompiler automatically copy these files as needed.


Documentation top
We have developed a number of documents describing Soot. Your main current sources of information are:
  • There are 2 accepted conference papers describing Soot.
  • A set of documents describing Soot, both as a Java application optimizer and as a compiler framework.
  • The Soot API. Most of the functionality is self-explanatory. This API is included in the Soot distribution.
  • The Soot source itself. It is full of examples on how to use the API.
  • The Soot mailing list. You can get a human response to your questions as well as browse the archive.

Mailing List top
The mailing list soot-list@sable.mcgill.ca is the primary forum for questions, discussions and comments on the Soot framework.

To subscribe, send an e-mail to majordomo@sable.mcgill.ca with subscribe soot-list in the body.

To unsubscribe, send an e-mail to majordomo@sable.mcgill.ca with unsubscribe soot-list in the body.

You can also view the mailing list archive.


Credits top
The official Soot maintainers are Raja Vallee-Rai, Patrick Lam, and Feng Qian.

Click here for the complete list of contributors and acknowledgements.


Last updated on January 29, 2001