The Parrot VM (40’)
Its goals and challenges for dynamic languages
François Perrad
francois.perrad@gadz.org
fperrad@OSDC.fr2009
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About Me
Parrot-porter since Oct 2005
In the TOP 10 of committers
Releaser Manager of Parrot 1.1.0
Packager for Windows (with mingw)
http://sourceforge.net/projects/parrotwin32/
~1 daily build on Smolder
Mostly a HLL implementor
Lua
WMLScript (bytecode translator)
Markdown
…
fperrad@OSDC.fr2009
Hobby : compiler writer
Not in core, but in languages ie user side
Check the goal of Parrot : not only a VM for Perl6
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About Parrot VM
a Virtual Machine started in 2001 …
targets dynamic languages
multi paradigm : functional, OO, …
Register based (not stack based)
Continuation Passing Style (CPS)
allows interoperability between HLL
(High Level Language)
reuse components
a great environment for HLL implementor
Visible side effects
CLR/DLR
JSR 292
fperrad@OSDC.fr2009
CLR : Common Language Runtime
DLR : Dynamic Language Runtime
JSR : Java Specification Request
JSR 292 : Supporting Dynamically Typed Languages on the Java Platform
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About commodity
commodity (*) is some good for which
there is demand, but which is
supplied without qualitative
differentiation across a market
An example
generic pharmaceuticals
the interest for customers is lower
prices
(*) : Source Wikipedia
fperrad@OSDC.fr2009
Now, do some Marketing
Not the best product, just enougt
until the next technological breakthrough.
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About commoditization
commoditization (*) is the process by which
goods that have economic value and are
distinguishable in terms of attributes
(uniqueness or brand) end up becoming
simple commodities in the eyes of the
market or consumers.
An example : Eclipse IDE
IBM gives/opens its codebase
the IDE market disappears
competitors die or survive in niche segment
a new market : plugins for Eclipse
Who is best placed in this market ?
Who controls the Eclipse roadmap ?
(*) : Source Wikipedia
fperrad@OSDC.fr2009
Industrial & FOSS objectives
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A stack of commodities
My Web App
fperrad@OSDC.fr2009
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A stack of commodities
My Web App
Hardware
fperrad@OSDC.fr2009
In 1985, IBM commodotizes the Personal Computer
-Open Spec => compatible
-Harware : under control with Intel 8086
-Software : forget with Microsoft DOS
Apple survives in niche
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A stack of commodities
My Web App
Operating System
Hardware : x86
fperrad@OSDC.fr2009
With Moore Law, x86 becomes server
Unix guys dislike i386
The winner is Linux, distributed FOSS development.
MS Windows (proprietary) is on Desktop.
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A stack of commodities
My Web App
Web Framework
Operating System : Linux
Hardware : i386
fperrad@OSDC.fr2009
Only FOSS actors, but 2 flavors :
OW2 & Apache Fondation : consortium (R&D mutualisation), Java
Dynamic languages (geek) : Catalyst (Perl), Rails (Ruby),
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A stack of commodities
My Web App
Web Framework
Virtual Machine (Interpreter)
Operating System : Linux
Hardware : i386 – multi core
fperrad@OSDC.fr2009
.NET CLR/DLR & mono
JVM
Parrot
frequency grow is ended,
Moore Law deals now with Multi core processor
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Dynamic languages grow
fperrad@OSDC.fr2009
Not yet majority
But dynamic/static ratio moves from 30-70% to 40-60%
In the following slides, I sort languages by their rank on TIOBE (Sept 2009)
3. PHP
5. VB.NET
6. Perl
8. Python
9. JavaScript
10. Ruby
19. Lua
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C/C+ implementation
PHP PHP 4.x, PHP 5.x
VisualBasic -
Perl Perl 5.8, Perl 5.10
Python CPython 2.6, CPython 3.1,
Stackless, Psyco V2 (JIT),
Unladen Swallow 2.6 (llvm)
JavaScript SpiderMonkey, V8, …
Ruby Ruby 1.8, Ruby 1.9 (YARV),
Rubinius
Lua Lua 5.1, LuaJIT 5.1
fperrad@OSDC.fr2009
Excludes all bridge
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JVM implementation
PHP -
Perl -
Python JPython 2.5
JavaScript Rhino
Ruby JRuby 1.8
Lua Kahlua (J2ME)
Scala Scala 2.7
Groovy Groovy 1.6
fperrad@OSDC.fr2009
No VB.NET & never
Groovy new entrant, and a special case : targets only JVM
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.NET/mono implementation
PHP Phalanger
VisualBasic VB.NET
Perl -
Python IronPython
JavaScript JScript.NET
Ruby IronRuby
Lua -
Scala ?
fperrad@OSDC.fr2009
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Challenges
Languages must move on VM
Initial C implementation is just a prototyp or a
prove of concept
Open Source resources are limited
Efforts are duplicated
in language
in libraries binding
in module & framework
core language or full modules ?
fperrad@OSDC.fr2009
Jython example :
- targets last CPython
- targets CPython modules
- targets JVM, just a script language with access to Java objet/classe/framework
Groovy has not this kind of dilemme.
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Conditions for success
Official Specifications (vs reference
implementation)
rubyspec.org/ (Rubinius)
perlcabal.org/syn/ (Perl6)
Official & huge Test Suite
svn.pugscode.org/pugs/t/spec/ (Perl6)
Mostly implements the language with
the language itself
codespeak.net/pypy/ (Python)
User friendly policies for support,
version, maintenance, …
fperrad@OSDC.fr2009
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Features for HLL implementor
Multiple runcore (opcode interpreter)
switch, C goto, profiler, …
GC - Garbage Collection
Exception mechanism
Unicode support (ICU)
PBC - a bytecode file format
Dynamic PMC (PolyMorphic Container)
build the HLL types as object
as shared library
Dynamic Opcode
as shared library
NCI - Native Call Interface
a FFI mechanism
fperrad@OSDC.fr2009
FFI : Foreign function interface
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Features for HLL implementor
PIR – Parrot Intermediate Representation
the interface of Parrot
an OO assembler, with rich calling convention
4 types : int, num, string, pmc
PCT - Parrot Compiler Toolkit
PGE – Parrot Grammar Engine
parse the source
produce an AST (Abtract Syntax Tree)
NQP – Not Quite Perl
describes action on AST
HLLCompiler : base class for a compiler
PIR generation from AST
fperrad@OSDC.fr2009
PGE is a recursive descent parser + operator precedence
NQP is a subset of Perl6
As example, the core of Lua on Parrot is only 4 KLOC
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Roadmap : some milestones
2005 : PGE
Jan 2008 : NQP availability
Start of Rakudo dev.
Mar 2009 : Parrot 1.0
API stable (with deprecation rules)
Installable
Languages leave the nest
Jul 2009 : Parrot 1.4
refactoring
fperrad@OSDC.fr2009
Development based on monthly release
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Roadmap : next milestones
??? : Plumage – Module ecosystem
trac.parrot.org/parrot/wiki/ModuleEcosystem
gitorious.org/parrot-plumage/parrot-plumage
Jan 2010 : Parrot 2.0
2010 Q1 : Rakudo Star
a large subset of Perl6 usable in real world
Updated roadmap
trac.parrot.org/parrot/report/14
fperrad@OSDC.fr2009
Plumage :
- metadata search
- handles dependencies
- install modules
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Bibliography / Webography
www.parrot.org
trac.parrot.org
F. Elie, Économie du logiciel libre, Eyrolles
Virtual Machine Showdown: Stack Versus
Registers
The Structure and Performance of Efficient
Interpreters
How to not write Virtual Machines for Dynamic
Languages
fperrad@OSDC.fr2009
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"one bytecode to rule them all"
fperrad@OSDC.fr2009
Credit : http://img-fan.theonering.net/rolozo/images/verger/PICT1619.JPG
Credit : http://img-fan.theonering.net/rolozo/images/verger/PICT1619.JPG
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