2008-09-13 Atsushi Enomoto <atsushi@ximian.com>

[mono.git] / web / c-sharp

diff --git a/web/c-sharp b/web/c-sharp
index bb9218db3e1e16b6343333bbb1e0ee497b969c43..ffa0b574bef43950ccb928ef65edad10ff7409fe 100644 (file)
--- a/web/c-sharp
+++ b/web/c-sharp
@@ -1,15 +1,42 @@
 * MCS: The Ximian C# compiler
 
 * MCS: The Ximian C# compiler
 

-       MCS began as an experiment to learn the features of C# by
-       writing a large C# program.  MCS is currently able to parse C#
-       programs and create an internal tree representation of the
-       program.  MCS can parse itself.  
+       The Mono C# compiler is considered feature C# 1.0 complete at
+       this point and mature.  MCS is able to compile itself and many
+       more C# programs (there is a test suite included that you can
+       use).  It is routinely used to compile Mono, roughly 1.7
+       million lines of C# code.

 
 

-       Work is progressing quickly on various fronts in the C#
-       compiler.  Recently I started using the System.Reflection API
-       to load system type definitions and avoid self-population of
-       types in the compiler and dropped my internal Type
-       representation in favor of using the CLI's System.Type.  
+       The compiler is also fairly fast.  On a IBM ThinkPad t40 it
+       compiles 18,000 lines of C# code per second.
+
+       Work on C# 2.0 has started: some pieces of it are available on
+       the standard compiler with the -2 switch (iterators, method
+       conversions) and some others are available on the `gmcs'
+       branch on CVS (generics)
+
+** Obtaining MCS
+
+       The Mono C# compiler is part of the `mcs' module in the Mono CVS
+       you can get it from our <a href="anoncvs.html">Anonymous CVS</a> server,
+       or you can get nightly <a href="download.html">download page</a>.
+
+** Running MCS
+
+       MCS is written in C# and uses heavily the .NET APIs.  MCS runs
+       on Linux with the Mono runtime and on Windows with both the
+       .NET runtime and the Mono runtime.
+
+** Reporting Bugs in MCS
+
+       When you report a bug, try to provide a small test case that would
+       show the error so we can include this as part of the Mono C# regression
+       test suite.
+
+       If the bug is an error or a warning that we do not flag, write
+       a sample program called `csXXXX.cs' where XXXX is the code number
+       that is used by the Microsoft C# compiler that illustrates the 
+       problem.  That way we can also do regression tests on the invalid
+       input.  

 
 ** Phases of the compiler
 
 
 ** Phases of the compiler
 


@@ -42,62 +69,82 @@
                  have to postpone this decision until the above steps
                  are finished.
 
                  have to postpone this decision until the above steps
                  are finished.
 

-               * Code generation: nothing done so far, but I do not
-                 expect this to be hard, as I will just use
-                 System.Reflection.Emit to generate the code. 
-       
+               * Code generation: The code generation is done through
+                 the System.Reflection.Emit API.

        </ul>
 
        </ul>
 

-<a name="tasks">
-** Current pending tasks
+** CIL Optimizations.

 
 

-       Simple tasks:
+       The compiler performs a number of simple optimizations on its input:
+       constant folding (this is required by the C# language spec) and 
+       can perform dead code elimination.

 
 

-       <ul>
-               * Array declarations are currently being ignored, 
+       Other more interesting optimizations like hoisting are not possible
+       at this point since the compiler output at this point does not
+       generate an intermediate representation that is suitable to
+       perform basic block computation.  

 
 

-               * PInvoke declarations are not supported.
+       Adding an intermediate layer to enable the basic block
+       computation to the compiler should be a simple task, but we
+       are considering having a generic CIL optimizer.  Since all the
+       information that is required to perform basic block-based
+       optimizations is available at the CIL level, we might just skip
+       this step altogether and have just a generic IL optimizer that
+       would perform hoisting on arbitrary CIL programs, not only
+       those produced by MCS.  

 
 

-               * Pre-processing is not supported.
+       If this tool is further expanded to perform constant folding
+       (not needed for our C# compiler, as it is already in there)
+       and dead code elimination, other compiler authors might be
+       able to use this generic CIL optimizer in their projects
+       reducing their time to develop a production compiler. 

 
 

-               * Attribute declarations and passing currently ignored.
+* Open bugs

 
 

-               * Compiler does not pass around line/col information from tokenizer for error reporting.
+       See the <a href="bugs.html">bugs page</a> for more information.

 
 

-               * Jay does not work correctly with `error'
-                 productions, making parser errors hard to point.  It
-                 would be best to port the Bison-To-Java compiler to
-                 become Bison-to-C# compiler (bjepson@oreilly.com
-                 might have more information)
-       </ul>
+       A test suite is maintained to track the progress of
+       the compiler and various programs are routinely compiled and
+       ran.

 
 

-       Interesting and Fun hacks to the compiler:
+* Slides

 
 

-       <ul>
-               * Finishing the JB port from Java to C#.  If you are
-                 interested in working on this, please contact Brian
-                 Jepson (bjepson at oreilly d-o-t com).
+       Slides for the Mono C# Compiler presentation at .NET ONE are
+       available <a
+       href="http://primates.ximian.com/~miguel/slides-europe-nov-2002/Mono_C_Sharp_Overview_1007.sxi">here</a>
+       in StarOffice format.

 
 

-                 More on JB at: <a href="http://www.cs.colorado.edu/~dennis/software/jb.html">
-                 http://www.cs.colorado.edu/~dennis/software/jb.html</a>
+** History

 
 

-                 JB will allow us to move from the Berkeley Yacc
-                 based Jay to a Bison-based compiler (better error
-                 reporting and recovery).
+       MCS was able to parse itself on April 2001, MCS compiled itself
+       for the first time on December 28 2001.  MCS became self hosting
+       on January 3rd, 2002. 

 
 

-               * Semantic Analysis: Return path coverage and
-                 initialization before use coverage are two great
-                 features of C# that help reduce the number of bugs
-                 in applications.  It is one interesting hack.
+       The Mono Runtime and the Mono execution engine were able to make
+       our compiler self hosting on March 12, 2002.

 
 

-               * TypeRefManager.  This exists currently in its infancy only. 
+** Questions and Answers

 
 

-               * Enum resolutions: it is another fun hack, as enums can be defined 
-                 in terms of themselves (<tt>enum X { a = b + 1, b = 5 }</tt>). 
+Q: Does the Mono C# compiler support C# 2.0?

 
 

-       </ul>
+A: At this point the Mono C# compiler supports some of the features of
+   C# 2.0, but the support has not been completed.   To enable 2.0 features
+   you must use the -2 flag to the compiler.

 
 

-** Questions and Answers
+Q: What features are available as of Feb 2004?
+
+A: Iterators have been implemented as well as method group implicit
+   conversion to delegates on the main compiler branch.
+
+   We have a branch of the compiler in the module `mcs/gmcs' which is
+   where we are developing the Generics support for the compiler.  Plenty
+   of tests work (see mcs/tests/gen-*.cs for a list of tests), but work
+   remains to be done.
+
+Q: Will the C# 2.0 features be part of the Mono 1.0 release?
+
+A: Only a few, the generic compiler will not be part of the 1.0
+   stable release, but a beta preview will be distributed.

 
 Q: Why not write a C# front-end for GCC?
 
 
 Q: Why not write a C# front-end for GCC?
 


@@ -123,6 +170,10 @@ Q: If your C# compiler is written in C#, how do you plan on getting
    We will do this through an implementation of the CLI Virtual
    Execution System for Unix (our JIT engine). 
 
    We will do this through an implementation of the CLI Virtual
    Execution System for Unix (our JIT engine). 
 

+   Our JIT engine is working for the purposes of using the compiler.
+   The supporting class libraries are being worked on to fully support
+   the compiler.
+

 Q: Do you use Bison?
 
 A: No, currently I am using Jay which is a port of Berkeley Yacc to
 Q: Do you use Bison?
 
 A: No, currently I am using Jay which is a port of Berkeley Yacc to