3 The Mono runtime will implement the JIT engine (and a byte
4 code interpreter for quickly porting to new systems), the
5 class loader, the garbage collector, threading system and
6 metadata access libraries.
8 We currently have two runtimes:
11 * <b>mint:</b> The Mono interpreter. This is an
12 easy-to-port runtime engine.
14 * <b>mono:</b> The Just In Time compiler implemented
15 using a BURS instruction selector
18 Currently both runtimes are missing garbage collection. We
19 are planning on using the ORP GC engine and deploy it by
22 ** Executing MSIL/CIL images
24 The code will load an executable and map the references to
25 external assemblies to our own version of the assemblies on
28 Our roadmap looks like this, this has been updated as of
33 * Milestone 1: <b>Done</b> Fully read and parse all CIL byte-codes
34 and metadata tokens (ie, a disassembler).
36 * Milestone 2: <b>Done</b> Complete an interpreter for CIL byte
37 codes. This interpreter can be used temporarly to
38 run CIL byte code on a system where no JIT is
41 * Milestone 3: <b>Done</b>Define an <i>lburg</i>-like
42 instruction selector for the JITer for Intel.
44 * Milestone 4: <b>Done</b> Implement JITer. This is where our
45 current efforts are focused on, the JITer currently runs
46 all of the code we have tested on it. The major limitation
47 is that our class libraries are not complete, and hence not
48 every application can be ran.
50 * Milestone 5: Port of the JITer to non IA32 systems.
53 A setup similar to the Kaffe JIT engine will be used to
54 layout the code to support non-IA32 architectures. Our work
55 will be focused on getting a IA32 version running first.
57 The JIT engine should work on Linux and Win32, although you
58 will need to install the CygWin32 development tools to get a
59 Unix-like compilation environment (mostly we use GNU make in
60 a few of the makefiles).
62 ** JIT Engine (<b>updated, Dec 18th, 2001</b>)
64 The JIT engine uses a code-generator generator approach for
65 compilation. Given the properties of CIL byte codes, we can
66 take full advantage of a real instruction selector for our
69 There are a couple of books that deal with this technique: "A
70 Retargetable C Compiler" and "Advanced Compiler Design and
71 Implementation" are good references. You can also get a
72 technical description of <a
73 href="http://research.microsoft.com/copyright/accept.asp?path=http://www.research.microsoft.com/~drh/pubs/iburg.pdf&pub=ACM">lbrug</a>.
75 A few papers that describe the instruction selector:
78 * <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>
81 * <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>
87 We will be using the Intel ORP GC engine as it provides a precise
88 garbage collector engine, similar to what is available on the
91 Although using a conservative garbage collector like Bohem's
92 would work, all the type information is available at runtime,
93 so we can actually implement a better collector than a
94 conservative collector.
97 * Garbage collection list and FAQ:<br>
98 <a href="http://www.iecc.com/gclist/">http://www.iecc.com/gclist/</a>
100 * "GC points in a Threaded Environment":<br>
101 <a href="http://research.sun.com/techrep/1998/abstract-70.html">
102 http://research.sun.com/techrep/1998/abstract-70.html</a>
104 * "A Generational Mostly-concurrent Garbage Collector":
105 <a href="http://research.sun.com/techrep/2000/abstract-88.html">
106 http://research.sun.com/techrep/2000/abstract-88.html</a>
108 * Details on The Microsoft .NET Garbage Collection Implementation:<br>
109 <a href="http://msdn.microsoft.com/library/default.asp?url=/library/en-us/dnmag00/html/GCI.asp">http://msdn.microsoft.com/library/default.asp?url=/library/en-us/dnmag00/html/GCI.asp</a>
110 <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>
115 The ECMA runtime and the .NET runtime assume an IO model and a
116 threading model that is very similar to the Win32 API.
118 Dick Porter has been working on the Mono abstraction layer
119 that allows our runtime to execute code that depend on this
124 Paolo Molaro found a few interesting links:
127 * On compilation of stack-based languages:<br>
128 <a href="http://www.complang.tuwien.ac.at/projects/rafts.html">
129 http://www.complang.tuwien.ac.at/projects/rafts.html</a>
131 * A paper on fast JIT compilation of a stack-based language:<br>
132 <a href="http://www.research.microsoft.com/~cwfraser/pldi99codegen.pdf">
133 http://www.research.microsoft.com/~cwfraser/pldi99codegen.pdf</a>
135 * Vmgen generates much of the code for efficient virtual machine (VM)
136 interpreters from simple descriptions of the VM instructions:<br>
137 <a href="http://www.complang.tuwien.ac.at/anton/vmgen/">
138 http://www.complang.tuwien.ac.at/anton/vmgen</a>
143 PInvoke is the mechanism we are using to wrap Unix API calls
144 as well as talking to system libraries.
146 Initially we used libffi, but it was fairly slow, so we have
147 reused parts of the JIT work to create efficient PInvoke trampolines.