* The Mono runtime
- The Mono runtime will implement the JIT engine (and a byte
- code interpreter for quickly porting to new systems), the
- class loader, the garbage collector, threading system and
- metadata access libraries.
+ The Mono runtime implements a JIT engine for the CIL virtual
+ machine (as well as a byte code interpreter, this is to
+ quickly port it to new systems), the class loader, the garbage
+ collector, threading system and metadata access libraries.
- Currently the runtime has an image loader and metadata access
- entry points. The runtime comes with a simple interpreter
- that can execute very simple programs.
+ We currently have two runtimes:
+
+ <ul>
+ * <b>mono:</b> The Just In Time compiler implemented
+ using a BURS instruction selector. We only support
+ x86 machines in the JIT engine at this point.
+
+ * <b>mint:</b> The Mono interpreter. This is an
+ easy-to-port runtime engine.
+ </ul>
+
+ Currently both runtimes are missing garbage collection. We
+ are planning on using the ORP GC engine and deploy it by
+ middle January.
+
+* COM and XPCOM
+
+ We plan on adding support for XPCOM on Unix and COM on Microsoft
+ Windows later in our development process.
** Executing MSIL/CIL images
The code will load an executable and map the references to
external assemblies to our own version of the assemblies on
- GNU/Linux.
+ Linux.
Our roadmap looks like this, this has been updated as of
- <b>Jul 15, 2001</b>:
+ <b>Dec 18, 2001</b>:
<ul>
- * Milestone 1: <b> Done</b> Fully read and parse all CIL byte-codes
+ * Milestone 1: <b>Done</b> Fully read and parse all CIL byte-codes
and metadata tokens (ie, a disassembler).
- * Milestone 2: Complete an interpreter for CIL byte
+ * Milestone 2: <b>Done</b> Complete an interpreter for CIL byte
codes. This interpreter can be used temporarly to
run CIL byte code on a system where no JIT is
available.
- * Milestone 3: Define an <i>lburg</i>-like instruction
- selector for the JITer for Intel. Although slower
- at JITing than a streaming JITer, it generates
- better code. The same grammar can later be used for
- the stream jitter.
+ * Milestone 3: <b>Done</b>Define an <i>lburg</i>-like
+ instruction selector for the JITer for Intel.
- * Milestone 4: Implement JITer.
+ * Milestone 4: <b>Done</b> Implement JITer. This is where our
+ current efforts are focused on, the JITer currently runs
+ all of the code we have tested on it. The major limitation
+ is that our class libraries are not complete, and hence not
+ every application can be ran.
* Milestone 5: Port of the JITer to non IA32 systems.
</ul>
- A setup similar to the Kaffe JIT engine can be used to
+ A setup similar to the Kaffe JIT engine will be used to
layout the code to support non-IA32 architectures. Our work
will be focused on getting a IA32 version running first.
The JIT engine should work on Linux and Win32, although you
will need to install the CygWin32 development tools to get a
- Unix-like compilation environment.
+ Unix-like compilation environment (mostly we use GNU make in
+ a few of the makefiles).
-** JIT Engine (<b>updated, Jul 14th, 2001</b>)
+** JIT Engine (<b>updated, Dec 18th, 2001</b>)
- We will be using a code-generator generator approach for our
- JITer. Given the properties of CIL byte codes, we can take
- full advantage of a real instruction selector for our code
- generator.
+ The JIT engine uses a code-generator generator approach for
+ compilation. Given the properties of CIL byte codes, we can
+ take full advantage of a real instruction selector for our
+ code generator.
There are a couple of books that deal with this technique: "A
Retargetable C Compiler" and "Advanced Compiler Design and
Implementation" are good references. You can also get a
technical description of <a
- href="http://research.microsoft.com/copyright/accept.asp?path=http://www.research.microsoft.com/~drh/pubs/iburg.pdf&pub=ACM">lbrug</a>
+ href="http://research.microsoft.com/copyright/accept.asp?path=http://www.research.microsoft.com/~drh/pubs/iburg.pdf&pub=ACM">lbrug</a>.
- Previously we had looked at a number of JIT engines and tools,
- but they would not take full advantage of the CIL properties:
+ A few papers that describe the instruction selector:
<ul>
- * <a
- href="http://www.intel.com/research/mrl/orp/">ORP</a>
+ * <a href="http://research.microsoft.com/copyright/accept.asp?path=http://www.research.microsoft.com/~drh/pubs/interface.pdf&pub=wiley">A code generation interface for ANSI C</a>
- * <a
- href="http://www.gnu.org/software/lightning/">GNU
- Lightning</a>
- * <a href="http://www.eecs.harvard.edu/~nr/toolkit/">NJ Machine
- Toolkit</a>.).
+ * <a href="http://research.microsoft.com/copyright/accept.asp?path=http://www.research.microsoft.com/~drh/pubs/iburg.pdf&pub=ACM">Engineering efficient code generators using tree matching and dynamic programming.</a>
- * VCODE.
</ul>
** Garbage Collection
- We have decided to implement a generational tracing garbage
- collector, which is very similar to the one being used by
- .NET. For an introduction to the garbage collection system
- used by Microsoft's CLR implementation, you can read this book
- on <a
- href="http://www.amazon.com/exec/obidos/ASIN/0471941484/o/qid=992556433/sr=2-1/ref=aps_sr_b_1_1/103-5866388-0492603">Garbage
- Collection.</a>
-
- Another consideration is to use the same interface that ORP
- uses to its Garbage Collection system and reuse that GC system
- instead of rolling our own, as the ORP system is pretty advanced
- and is independent of the rest of ORP.
+ We will be using the Intel ORP GC engine as it provides a precise
+ garbage collector engine, similar to what is available on the
+ .NET environment.
Although using a conservative garbage collector like Bohem's
would work, all the type information is available at runtime,
<a href="http://msdn.microsoft.com/library/default.asp?url=/library/en-us/dnmag00/html/GCI2.asp">http://msdn.microsoft.com/library/default.asp?url=/library/en-us/dnmag00/html/GCI2.asp</a>
</ul>
+** IO and threading
+
+ The ECMA runtime and the .NET runtime assume an IO model and a
+ threading model that is very similar to the Win32 API.
+
+ Dick Porter has been working on the Mono abstraction layer
+ that allows our runtime to execute code that depend on this
+ behaviour.
+
** Useful links
Paolo Molaro found a few interesting links:
PInvoke is the mechanism we are using to wrap Unix API calls
as well as talking to system libraries.
- We hvae implemented PInvoke through libffi, but we are likely
- going to roll our own system as the runtime matures, specially
- as the interpreter is approaching completion, and we move into
- the JITer.
+ Initially we used libffi, but it was fairly slow, so we have
+ reused parts of the JIT work to create efficient PInvoke trampolines.