https://github.com/minad/chasm

Java Bytecode Assembler and Disassembler which uses S-expressions
https://github.com/minad/chasm

asm assembler bytecode disassembler java java-bytecode s-expressions

Last synced: 9 months ago
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Java Bytecode Assembler and Disassembler which uses S-expressions

• Host: GitHub
• URL: https://github.com/minad/chasm
• Owner: minad
• License: other
• Created: 2018-05-09T16:56:25.000Z (over 7 years ago)
• Default Branch: master
• Last Pushed: 2019-12-22T10:21:15.000Z (about 6 years ago)
• Last Synced: 2025-03-25T13:11:21.286Z (9 months ago)
• Topics: asm, assembler, bytecode, disassembler, java, java-bytecode, s-expressions
• Language: Java
• Homepage:
• Size: 1.43 MB
• Stars: 27
• Watchers: 2
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.adoc
  • License: LICENSE

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README

          
= Chasm - Java assembler and disassembler using S-expressions

Chasm can disassemble `{asterisk}.class` files and `{asterisk}.jar` files and output assembly in s-expression form.

Furthermore the main use case is to read s-expression assembly files and output `{asterisk}.class` or `{asterisk}.jar` files.

The s-expression syntax is both easy to parse and easy to generate.

Chasm uses the de-facto standard library ow2 ASM for bytecode generation. Since Chasm is only a minimal syntax on top of

ASM it is easy to keep it up to date with the current bytecode standard.

[source,scheme]

----

(class 53 (final public super) chasm/Main null java/lang/Object ()

 (source "Main.java" null)

 (inner-class chasm/Server$Command chasm/Server Command (abstract interface public static))

 (inner-class java/lang/invoke/MethodHandles$Lookup java/lang/invoke/MethodHandles Lookup (final public static))

 (method (public static) main "([Ljava/lang/String;)V" null (java/io/IOException)

  (code

   (label L0)

   (line 13 L0)

   (invokedynamic run "()Lchasm/Server$Command;"

    (H invokestatic java/lang/invoke/LambdaMetafactory metafactory

     "(Ljava/lang/invoke/MethodHandles$Lookup;Ljava/lang/String;Ljava/lang/invoke/MethodType;Ljava/lang/invoke/MethodType;Ljava/lang/invoke/MethodHandle;Ljava/lang/invoke/MethodType;)Ljava/lang/invoke/CallSite;" false)

    ((T "(Ljava/nio/file/Path;[Ljava/lang/String;Ljava/io/PrintStream;)V")

     (H invokestatic chasm/Main run

      "(Ljava/nio/file/Path;[Ljava/lang/String;Ljava/io/PrintStream;)V" false)

     (T "(Ljava/nio/file/Path;[Ljava/lang/String;Ljava/io/PrintStream;)V")))

   (aload 0)

   (invokestatic chasm/Server main "(Lchasm/Server$Command;[Ljava/lang/String;)V")

   (label L1)

   (line 14 L1)

   (return)

   (label L2)

   (local args "[Ljava/lang/String;" null L0 L2 0)

   (maxs 2 1)))

...

----

See link:example.chasm[] for the full example.

== Quick start

1. Build with `gradle` or use the precompiled binary in `dist` (reproducible build).

2. Disassemble class/jar file to chasm with `chasm example.{class|jar} example.chasm`

2. Assemble chasm to class/jar file with `chasm example.chasm example.{class|jar}`

== Binary version

The 'dist' directory contains a precompiled version which includes

a copy of ASM.

== License

MIT (c) 2018 Daniel Mendler

ASM: a very small and fast Java bytecode manipulation framework

Copyright (c) 2000-2011 INRIA, France Telecom

All rights reserved.

== Related projects

* http://asm.ow2.io/[ObjectWeb ASM]

* https://wiki.openjdk.java.net/display/CodeTools/asmtools[jdk asmtools]

* https://github.com/achmelev/lilac[Lilac]

** Does perfect roundtrip like chasm

** Overall more complex and more complex syntax

** Not based on ObjectWeb ASM

* https://github.com/Storyyeller/Krakatau[Krakatau]

** Written in Python

** Includes a decompiler

* https://github.com/davidar/jasmin[Jasmin]

* https://github.com/Whiley/Jasm[Whiley Jasm]

* http://www.judoscript.org/articles/jamaica.html[Jamaica]

* https://commons.apache.org/proper/commons-bcel/[BCEL]