avian

Avian - A lightweight Java Virtual Machine (JVM)

PLEASE NOTE: This project is not currently being developed, maintained, or supported. Feel free to use and/or fork it, but any issues filed here will probably be ignored. Quick Start

These are examples of building Avian on various operating systems for the x86_64 architecture. You may need to modify JAVA_HOME according to where the JDK is installed on your system. In all cases, be sure to use forward slashes in the path.

on Linux:

$ export JAVA_HOME=/usr/lib/jvm/java-7-openjdk-amd64
$ make
$ build/linux-x86_64/avian -cp build/linux-x86_64/test Hello

on Mac OS X:

$ export JAVA_HOME=$(/usr/libexec/java_home)
$ make
$ build/macosx-x86_64/avian -cp build/macosx-x86_64/test Hello

on Windows (Cygwin):

$ git clone [email protected]:ReadyTalk/win64.git ../win64
$ export JAVA_HOME="/cygdrive/c/Program Files/Java/jdk1.7.0_45"
$ make
$ build/windows-x86_64/avian -cp build/windows-x86_64/test Hello

on FreeBSD:

$ export JAVA_HOME=/usr/local/openjdk7
$ gmake
$ build/freebsd-x86_64/avian -cp build/freebsd-x86_64/test Hello

Introduction

Avian is a lightweight virtual machine and class library designed to provide a useful subset of Java's features, suitable for building self-contained applications.

Supported Platforms

Avian can currently target the following platforms:

• Linux (i386, x86_64, ARM, and ARM64)
• Windows (i386 and x86_64)
• Mac OS X (i386 and x86_64)
• Apple iOS (i386, x86_64, ARM, and ARM64)
• FreeBSD (i386, x86_64)

Building

Build requirements include:

• GNU make 3.80 or later
• GCC 4.6 or later or LLVM Clang 3.1 or later (see use-clang option below)
• JDK 1.6 or later
• MinGW 3.4 or later (only if compiling for Windows)
• zlib 1.2.3 or later

Earlier versions of some of these packages may also work but have not been tested.

The build is directed by a single makefile and may be influenced via certain flags described below, all of which are optional.

$ make \
    platform={linux,windows,macosx,ios,freebsd} \
    arch={i386,x86_64,arm,arm64} \
    process={compile,interpret} \
    mode={debug,debug-fast,fast,small} \
    lzma= \
    bootimage={true,false} \
    tails={true,false} \
    continuations={true,false} \
    use-clang={true,false} \
    openjdk= \
    openjdk-src= \
    android= \
    ios-version=

• platform - the target platform

  • default: output of $(uname -s | tr [:upper:] [:lower:]), normalized in some cases (e.g. CYGWIN_NT-5.1 -> windows)

• arch - the target architecture

  • default: output of $(uname -m), normalized in some cases (e.g. i686 -> i386)

• process - choice between pure interpreter or JIT compiler

  • default: compile

• mode - which set of compilation flags to use to determine optimization level, debug symbols, and whether to enable assertions

  • default: fast

• lzma - if set, support use of LZMA to compress embedded JARs and boot images. The value of this option should be a directory containing a recent LZMA SDK (available here). Currently, only version 9.20 of the SDK has been tested, but other versions might work.

  • default: not set

• armv6 - if true, don't use any instructions newer than armv6. By default, we assume the target is armv7 or later, and thus requires explicit memory barrier instructions to ensure cache coherency

• bootimage - if true, create a boot image containing the pre-parsed class library and ahead-of-time compiled methods. This option is only valid for process=compile builds. Note that you may need to specify both build-arch=x86_64 and arch=x86_64 on 64-bit systems where "uname -m" prints "i386".

  • default: false

• tails - if true, optimize each tail call by replacing the caller's stack frame with the callee's. This convention ensures proper tail recursion, suitable for languages such as Scheme. This option is only valid for process=compile builds.

  • default: false

• continuations - if true, support continuations via the avian.Continuations methods callWithCurrentContinuation and dynamicWind. See Continuations.java for details. This option is only valid for process=compile builds.

  • default: false

• use-clang - if true, use LLVM's clang instead of GCC to build. Note that this does not currently affect cross compiles, only native builds.

  • default: false

• openjdk - if set, use the OpenJDK class library instead of the default Avian class library. See "Building with the OpenJDK Class Library" below for details.

  • default: not set

• openjdk-src - if this and the openjdk option above are both set, build an embeddable VM using the OpenJDK class library. The JNI components of the OpenJDK class library will be built from the sources found under the specified directory. See "Building with the OpenJDK Class Library" below for details.

  • default: not set

• android - if set, use the Android class library instead of the default Avian class library. See "Building with the Android Class Library" below for details.

  • default: not set

• ios-version - the minimum iOS SDK version which will be used when compiling for ios target. Do not use a value 11.0 or larger, if you want to support 32 bit version. This option is only valid for platform=ios .

  • default: 8.0

These flags determine the name of the directory used for the build. The name always starts with ${platform}-${arch}, and each non-default build option is appended to the name. For example, a debug build with bootimage enabled on Linux/x86_64 would be built in build/linux-x86_64-debug-bootimage. This allows you to build with several different sets of options independently and even simultaneously without doing a clean build each time.

Note that not all combinations of these flags are valid. For instance, non-jailbroken iOS devices do not allow JIT compilation, so only process=interpret or bootimage=true builds will run on such devices. See here for an example of an Xcode project for iOS which uses Avian.

If you are compiling for Windows, you may either cross-compile using MinGW or build natively on Windows under Cygwin.

Installing Cygwin:

1. Download and run setup.exe from cygwin's website, installing the base system and these packages: make, gcc-mingw-g++, mingw64-i686-gcc-g++, mingw64-x86_64-gcc-g++, and (optionally) git.

You may also find our win32 repository useful: (run this from the directory containing the avian directory)

$ git clone [email protected]:ReadyTalk/win32.git

This gives you the Windows JNI headers, zlib headers and library, and a few other useful libraries like OpenSSL, libjpeg, and libpng. There's also a win64 repository for 64-bit builds:

  $ git clone [email protected]:ReadyTalk/win64.git

Building with the Microsoft Visual C++ Compiler

You can also build using the MSVC compiler, which makes debugging with tools like WinDbg and Visual Studio much easier. Note that you will still need to have GCC installed - MSVC is only used to compile the C++ portions of the VM, while the assembly code and helper tools are built using GCC.

Note that the MSVC build isn't tested regularly, so is fairly likely to be broken.

Avian targets MSVC 11 and above (it uses c++ features not available in older versions).

To build with MSVC, install Cygwin as described above and set the following environment variables:

$ export PATH="/usr/local/bin:/usr/bin:/bin:/usr/X11R6/bin:/cygdrive/c/Program Files/Microsoft Visual Studio 11.0/Common7/IDE:/cygdrive/c/Program Files/Microsoft Visual Studio 11.0/VC/BIN:/cygdrive/c/Program Files/Microsoft Visual Studio 11.0/Common7/Tools:/cygdrive/c/WINDOWS/Microsoft.NET/Framework/v3.5:/cygdrive/c/WINDOWS/Microsoft.NET/Framework/v2.0.50727:/cygdrive/c/Program Files/Microsoft Visual Studio 11.0/VC/VCPackages:/cygdrive/c/Program Files/Microsoft SDKs/Windows/v6.0A/bin:/cygdrive/c/WINDOWS/system32:/cygdrive/c/WINDOWS:/cygdrive/c/WINDOWS/System32/Wbem"
$ export LIBPATH="C:\WINDOWS\Microsoft.NET\Framework\v3.5;C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727;C:\Program Files\Microsoft Visual Studio 11.0\VC\LIB;"
$ export VCINSTALLDIR="C:\Program Files\Microsoft Visual Studio 11.0\VC"
$ export LIB="C:\Program Files\Microsoft Visual Studio 11.0\VC\LIB;C:\Program Files\Microsoft SDKs\Windows\v6.0A\lib;"
$ export INCLUDE="C:\Program Files\Microsoft Visual Studio 11.0\VC\INCLUDE;C:\Program Files\Microsoft SDKs\Windows\v6.0A\include;"

Adjust these definitions as necessary according to your MSVC installation.

Finally, build with the msvc flag set to the MSVC tool directory:

$ make msvc="/cygdrive/c/Program Files/Microsoft Visual Studio 11.0/VC"

Building with the OpenJDK Class Library

By default, Avian uses its own lightweight class library. However, that library only contains a relatively small subset of the classes and methods included in the JRE. If your application requires features beyond that subset, you may want to tell Avian to use OpenJDK's class library instead. To do so, specify the directory where OpenJDK is installed, e.g.:

$ make openjdk=/usr/lib/jvm/java-7-openjdk

This will build Avian as a conventional JVM (e.g. libjvm.so) which loads its boot class library and native libraries (e.g. libjava.so) from /usr/lib/jvm/java-7-openjdk/jre at runtime. Note that you must use an absolute path here, or else the result will not work when run from other directories. In this configuration, OpenJDK needs to remain installed for Avian to work, and you can run applications like this:

$ build/linux-x86_64-openjdk/avian-dynamic -cp /path/to/my/application \
    com.example.MyApplication

Alternatively, you can enable a stand-alone build using OpenJDK by specifying the location of the OpenJDK source code, e.g.:

$ make openjdk=$(pwd)/../jdk7/build/linux-amd64/j2sdk-image \
    openjdk-src=$(pwd)/../jdk7/jdk/src

You must ensure that the path specified for openjdk-src does not have any spaces in it; make gets confused when dependency paths include spaces, and we haven't found away around that except to avoid paths with spaces entirely.

The result of such a build is a self-contained binary which does not depend on external libraries, jars, or other files. In this case, the specified paths are used only at build time; anything needed at runtime is embedded in the binary. Thus, the process of running an application is simplified:

$ build/linux-x86_64-openjdk-src/avian -cp /path/to/my/application \
    com.example.MyApplication

Note that the resulting binary will be very large due to the size of OpenJDK's class library. This can be mitigated using UPX, preferably an LZMA-enabled version:

$ upx --lzma --best build/linux-x86_64-openjdk-src/avian

You can reduce the size futher for embedded builds by using ProGuard and the supplied openjdk.pro configuration file (see "Embedding with ProGuard and a Boot Image" below). Note that you'll still need to use vm.pro in that case -- openjdk.pro just adds additional constraints specific to the OpenJDK port. Also see app.mk in the avian-swt-examples project for an example of using Avian, OpenJDK, ProGuard, and UPX in concert.

Here are some examples of how to install OpenJDK and build Avian with it on various OSes:

Debian-based Linux:

Conventional build:

$ apt-get install openjdk-7-jdk
$ make openjdk=/usr/lib/jvm/java-7-openjdk test

Stand-alone build:

$ apt-get install openjdk-7-jd