Pharo is an open-source Smalltalk platform for professional use based on Squeak Smalltalk. It provides a flexible environment to support research into new language concepts. Over the past year, 377 updates were made to address 699 bug reports. Future plans include improvements to the compiler, slots system, and just-in-time (JIT) compilation and adaptive optimization (AOStA) techniques. The community is working on these and other enhancements to further enable evolution and experimentation.

1. Past and Future

2. What?
A progressive, open-source Smalltalk platform
for professional use.

3. What?
A flexible environment to support the research
of new language concepts.

4. What?
Pharo = Language + IDE
Pure Object-Oriented Language
Dynamically Typed

5. History
Based on Squeak Smalltalk
+ Major Cleanups (MVC, eToys)
+ New UI Look / TrueType
+ Tools
+ Block Closures
+ Lots of bugfixes and small improvements

6. 699 Bug-reports closed
377 Updates
Release Planned: August 2009

9. Getting
Started
(if needed)

10. Pier

11. Pier

12. Smalltalk with OO-Database
Pharo is the IDE

13. Future

14. ...cleaner

15. ...smaller

16. ...faster

17. (of course)

18. Enable
Evolution

19. Enable
Experiments

20. Examples
- Compiler
- Slots
- JIT and AOStA

21. Old Compiler
- From 1976
- Not OO
- Hard to understand. Hard to change
We need a better Compiler!

22. New Compiler
- Originally by Anthony Hannan
- Based on Visitors
- Reusable and Pluggable Backend (IRBuilder)
- Uses RB AST
- SmaCC Parser
Easier to understand.
Easier to change

23. New Compiler
Scanner Semantic Code
code AST AST Bytecode
/ Parser Analysis Generation
Code generation in detail
Build Bytecode
AST IR Bytecode
IR Generation
ASTTranslator IRTranslator
IRBuilder BytecodeBuilder

24. Plans...
- New BlockClosure Format
- Plugin architecture: Parser, Checker, CodeGen
- Use RB Parser (Faster, Error messages)

25. Examples
- Compiler
- Slots
- JIT and AOStA

26. Instance Vars
- Not objects
- Change behavior?
- Change memory layout?
Instance state should be more
powerful!

27. Slots
- Are objects
- Allow custom subclasses
- Change behavior and memory layout
Without Performance penalty!

28. Auto-Accessor
MopObject subclass: #SlotExample
slots: '{AutoAccessorSlot named: #hello}'
classVariableNames: ''
poolDictionaries: ''
category: 'SlotExamples'
Create accessor-methods at compile-time

29. Active Slot
MopObject subclass: #SlotExample
slots: '{ActiveSlot named: #hello
action: [Beeper beep]}'
classVariableNames: ''
poolDictionaries: ''
category: 'SlotExamples'
Evaluate block on read

30. Sparse Slot
MopObject subclass: #SlotExample
slots: '{SparseSlot named: #a.
SparseSlot named: #b.
SparseSlot named: #c}'
classVariableNames: ''
poolDictionaries: ''
category: 'SlotExamples'
Store values in one Dictionary

31. iVar Slot
MopObject subclass: #SlotExample
slots: '{IVarSlot named: #a}
classVariableNames: ''
poolDictionaries: ''
category: 'SlotExamples'
Normal instance Variable

32. Auto-Accessor
MopObject subclass: #SlotExample
slots: '{AutoAccessorSlot named: #hello}'
classVariableNames: ''
poolDictionaries: ''
category: 'SlotExamples'
Create accessor-methods at compiled-time

33. Slot subclass: #AutoAccessorSlot
instanceVariableNames: ''
....
postCreationAction
self generateGetter.
self generateSetter.
generateGetter
class compile:
(String streamContents: [:stream |stream
nextPutAll: self name; crtab;
nextPutAll: '^', self name asString])

34. Active Slot
MopObject subclass: #SlotExample
slots: '{ActiveSlot named: #hello
action: [Beeper beep]}'
classVariableNames: ''
poolDictionaries: ''
category: 'SlotExamples'
Evaluate block on read

35. Active Slot
AutoAccessorSlot subclass: #ActiveSlot
instanceVariableNames: 'action'
....
emitReadUsing: methodBuilder
methodBuilder
pushLiteral: action;
send: #value.
super emitReadUsing: methodBuilder

36. Status
- First Prototype
- Integration with ClassBuilder
- Compatibility with iVars
- Explore different designs

37. Examples
- Compiler
- Slots
- JIT and AOStA

38. VM
- Virtual Machine uses Interpreter
- JIT Compiler under development (Eliot Miranda)
How to optimize even more?

39. AOStA
- Provide API for accessing runtime data
- PIC: Polymorphic Inline Cache
Record class per send instruction
- Hotness Counter
Where do we spend time?

40. AOStA
PIC
BC 2 SSA 2
BC SSA OPT SSA BC
SSA BC
Optimize SSA-Form
(Static Single Assignment)

41. AOStA
- Use PIC-Data for specialization
- Inline often-called methods
- Special Bytecode for primitive types (Floats)

42. AOStA
- Bytecode-to-Bytecode optimization
- Purely realized in Smaltalk
- Accessible in the image. Reflection?

43. More...
- Improve Tools
- Real Modules
- Reflection
- .......

44. Join Us!
Goal: learning and having fun
http://pharo-project.org