cloudeecn / fiscevm

A JAVA-like VM in pure C

Fast Interpreter SCript Engine (former Feather-In SCript Engine)

This is a virtual machine which can run java's bytecode and has a (maybe) minimal subset of java runtime, which implemented in pure C.
用C语言实现的解释型Java虚拟机

Originally used as a cross-platform AVG script interpreter written in Java, but translated to C for portability(Yes! C is much more portable than Java.) and optimized faster and faster ;)
最初是是Java写的跨平台AVG用脚本引擎，完成后作者对跨平台脚本引擎的兴趣大增导致用C重写了一遍，从此走向了优化的不归路。

Highlights

• Portability: implemented in Pure C, most code complies ANSI-C90, with following exception which is :

  1 Native handler for System.currentTimeMillis() / System.nanoTime() uses gettimeofday in POSIX systems and QueryPerformanceCounter in windows.

  2 Need int64 type, use long long in GCC and __int64 in MSVC, you can also specific a custom int64 time for your platform.

  3 Threading-based dispatching scheme requires GCC/clang. Switch-based dispatching scheme is used in other compilers.

• Emulated multi-thread: Multi thread is not required on host OS.

• Save/Load state: Can dump VM's state at almost anytime(when vm is not busy running), and resume later

• Pure C code: Not familiar with ASM or C++? All VM code here are in pure C, some code in forth(vmgen), but compiled to C and these C code are in src. (Of course runtime code are in Java, as this is somehow a "java" VM)

• Performance: Linpack performance is almost as fast as java's interpreter mode in threading dispatch mode.

• Can run under java/android with JNI interface (Run java under java, pretty crazy huh?)

• No need to worry about license: The code of VM(fiscevm-c fiscevm-c-native fiscevm-ios) is licensed under the terms of the LGPL and the code of Runtime(fiscevm-runtime) is licensed under Apache. I choose these licenses on purpose of

  1 If you optimized fiscevm itself and release, please open source so the VM could become better and better.

  2 Anything you code that runs INSIDE fiscevm need not to be open-sourced.

Supports

Following are supported

• java.lang.*
• java.util.*
• java.math.*
• java.beans.*
• JNI
• Reflection
• Reference
• Proxy
• Regex
• Read file through Class.getResourceAsInputStream
• With native-invoke interface, you can always add more function into it

Following are NOT supported

• packages not listed above
• All security manager related function is mocked
• Multi/custom classloader
• Serialize (related classes are added for compatibility, but all these code does nothing ;)
• java.util.concurrent.*
• Runtime related functions
• Locales / Charsets (Supports only UTF-8)
• Network support

Quick start

Prerequisite

JDK1.6+, maven, CMake 3.0+ (optional)

Build runtime package

(at project base directory)
$cd fiscevm-runtime
$mvn compile

Now all base runtime classes are compiled into fiscevm-runtime/target/classes

Build test binery

With cmake

(at project base directory)
$cd fiscevm-c-native/src
$mkdir Build && cd Build
$cmake -DBUILD_TEST=ON ..
$make

Without cmake

(at project base directory)
$cd fiscevm-c-native/src
$mkdir Build && cd Build
$gcc -I../main/c -I../main/include -I../main/include-public -I../main/include-dev -flto -O3 -Wall -DNDEBUG -o fisce-test ../main/utils/Portable.c ../main/utils/MemMan.c ../main/utils/Utf8.c ../main/utils/String.c ../main/utils/BitSet.c ../main/utils/HashMap.c ../main/utils/HashMapI.c ../main/utils/ArrList.c ../main/utils/LnkList.c ../main/utils/Debug.c ../main/vmcore/Class.c ../main/vmcore/ClassLoader.c ../main/vmcore/CoreHandlers.c ../main/vmcore/MathHandlers.c ../main/vmcore/Debug.c ../main/vmcore/Data.c ../main/vmcore/Heap.c ../main/vmcore/Instructions.c ../main/vmcore/Preverifier.c ../main/vmcore/Thread.c ../main/vmcore/Engine.c ../main/vmcore/ThreadManager.c ../main/vmcore/VMContext.c ../main/vmcore/ExpDev.c ../main/vmcore/FiScE.c ../main/vmcore/FileInputStream.c ../main/vmcore/BinarySaver.c ../main/vmcore/DataLoader.c ../main/vmcore/BAIS.c ../main/vmcore/RIS.c ../test/vmcore/Test.c

Have fun

Run all tests

(at build directory, ie. fiscevm-c-native/src/Build)
$./fisce-test ./fisce-test ../../../fiscevm-runtime/target/classes

Run specific class

(at build directory, ie. fiscevm-c-native/src/Build)
$./fisce-test ./fisce-test ../../../fiscevm-runtime/target/classes <className>

Note. Package name separater in class-name should be "/" instead of ".".

Run specific class with multi classpaths

(at build directory, ie. fiscevm-c-native/src/Build)
$./fisce-test ./fisce-test ../../../fiscevm-runtime/target/classes [classpath ...] <className>

You can also build your own class with eclipse or maven to run with it!