moscow ml code generation for microsoft net

Moscow ML Code Generation for Microsoft .Net Niels Jørgen Kokholm Copenhagen Programming Language Seminar December 12th 2002... • Work in progress • With Peter Sestoft • Long time goal

Moscow ML Code Generation for

Microsoft Net

Niels Jørgen Kokholm Copenhagen Programming Language

Seminar December 12th 2002

Moscow ML

• Standard ML batch compiler (mosmlc)

• Standard ML Basis Library

• Interactive evaluation system (mosml)

• …

• Runs on CaML light runtime

• Written in Standard ML (and C)

Microsoft Net

• Microsoft NET Framework/ECMA CLI

– Common Language Runtime (CLR)

• Virtual “stack” machine specification similar to JVM

– NET Framework class libraries

• Implementations:

– MS NET SDK

– MS SSCLI (rotor)

– Mono

– DotGNU Portable.NET

• Work in progress

• With Peter Sestoft

• Long time goal: port Moscow ML to CLR

• Started as four week project at ITU

– May ’02 Andrzej Wasowski/PS

• Assess usability of CLR as execution platform for functional languages and the portability of Moscow ML

• Expand the range of HW/SW platforms on which Moscow ML run (or avoid porting CaML Light)

• Leverage the safety and productivity potential of strongly typed languages in high-end, distributed, XML-aware, E-yada yada yada

• Learn about code generation in a non-toy setting

and about NET

• Overall plan

– Feasibility study

• Can it be done with reasonable performance

– CLR code generation

• For pure Standard ML programs

– Basis Library part 1

• Parts used by compiler

– Bootstrap compiler

– Interactive system

– Basis Library part 2

• CLR code generation + library part 3

– May 2002

• Bootstrap compiler

– October 2002

– No floating point types, quote/antiquote, …

– No complete regression test

• Performance compared to current Moscow ML

– Small code benchmarks: 1-4 times as slow

– Bootstrapped compiler: 5 times as slow 

Status

Related work

• Moscow ML on JVM

– Peter Berthelsen, master thesis 1998

• SML.NET

– Andrew Kennedy, Claudio Russo, Nick Benton (MS Research), released June 2002

– Standard ML compiler on CLR

– Bootstrapped from SML/NJ

• F#

– Don Syme, MS Research

CaML light vs CLR

Evaluation stack accessible by

index

Only top of evaluation stack accessible

?

- Local variables

- Stack must be empty on entry to

try block

Tailor made types OO type system

? Tail recursion of method calls -

.uo exe, dll and netmodule files class

Textual assembler and RTCG library

Tailor made garbage collection All-purpose Garbage collection

Moscow ML Code Generation

1 Parsing, typecheck,

translation

2 Compilation:

a) Closure splitting

b) Expression

compilation

3 Byte code emission

B y t e c o d e

S y m b o l i c ( m a c r o ) b y t e c o d e ( u n t y p e d ) L a m b d a E x p r e s s i o n s

S M L P r o g r a m

Changing the backend 1

• Textual assembler vs RTCG?

• Verifiable or unverifiable code?

• Efficiency

Changing the backend 2

• Representation of run time values

• Correct tail recursion

• Exception handling

• Boxing of primitive types

Runtime value representation

Closures

Exception handling

Boxing of primitive types

Performance comparisons