[Mono-list] About CSC and MCS

He HongFu hfhe@stryon.com
Wed, 5 Nov 2003 8:34:48 +0000

Hi all:
=09There is just a suggestion about optimizing the MCS.
=09AFAIK, now the working flow of the current MCS as following:=
 firstly use CSharpParser to parse all source file,building type=
 tree, member token table, parsing all statement and expression=
 then resolving the type tree, finally defining the types,=
 emiting IL codes. Maybe I'm wrong about that.

=09And I get the working flow of CSC(Microsoft) when I parsing it.=
 The flow as following:
=09CSC compiles all files with four phases:
=09Phase 1.  Handle preprocessor directives, build type tree for=
 all files, and parse these type's member lexically and=
 syntactically. I think the work of this phase is building a=
 symbol table.

=09Phase 2.  Semantically parse the members of all defined type,=
 including type resolving. We can get type information from the=
 symbol table built above
=09Phase 3.  Semantically parse the members of all defined type,=
 such as method overload, Main entry defined, etc.
=09Phase 4.  Lexicallly, syntactically, Semantically parse the=
 member body such as method, property, sevolve statements
expressions, I don't know whether .
=09If errors occur in the one of the file in some phase, all file=
 will do util the same phase work was finished.
=09I have thought about the implementation of CSC for long time.=
 Why it did as that? As well known, the author of the CSC is=
 Anders Hejlsberg which is one of the best excellent programmer=
 of compiler. I just get some tiny reasons. I think the primary=
 advantage is that compiling multiple file and error handling.=
 First, the work flow of CSC can save obvious memory usage When=
 compiling multiple files. Second, if we have error in a file in=
 some phase, we can stop the following phase work after parsing=
 all files in the phase, and exit the compiler. And preprocessor=
 directive can be proprocessing without any overloads.

   Of course, the changes of MCS makes more overloads, and the=
 structure of CSC maybe not as many advantages as I thought. I
hope Mono hacker can cosider it carefully. Or if want to optimize=
 MCS, we can make a branch just for experiment.


=A1=A1=A1=A1=A1=A1=A1=A1=A1=A1=A1=A1=A1=A1=A1=A1He HongFu