todo.txt

todo:
- optimize floats
- optimize negative integers
- používat fce z StrSafe.h
- libicu, libiconv pro mb <=> wcs
- move Bytecode to GC
- add String::+(Object) operator and call Object::String() within
- fix String::createInstance
- fix Array::createInstance
- count method->maxStack from bc
- priorities for tasks
- default value for value types
- Null class for 0x00000000
- Mark all created of returned-to frames as GC_DIRTY, so that GC have to scan them (old frames mark through return address fn)
- Copy Frame to Heap if referenced by task (async call)
- Classes created by MetaClass::createInstance()
- Use FrameInspector in Debugger
- Bytecode as Object; Bytecode class; Bytecode traversing
- Thread as Object; Thread class; Thread traversing
- move instruction dump from Bytecode elsewhere
- Cache a couple of frames in Pool (per Thread)
- EntryPoint flag for Class (only for classes with non-abstract run method)
- safe point at backward jumps
- No selector in method
- Abstract createInstance throwing an exception for abstract classes
- Abstract function throwing an exception for abstract methods
- Thread-safe lazy load of classes
- no thread inheriting in VM, Debugger
- entry point task ctor
- make class library thread-safe and extract it from VM
- fix pointers to tasks
- fix pointers to awaiting tasks


bytecode optimalization:
- adaptive optimizing - monitor execution of code and optimize most used bytecode (hot spot, 10-20% that is executed 80-90% of time)
- Evaluate constant expressions
- Remove unnecessary field accesses and method calls
- Remove unnecessary branches
- Remove unnecessary comparisons and instanceof tests
- Remove unused code blocks
- Merge identical code blocks
- Reduce variable allocation
- Remove write-only fields and unused method parameters
- Inline constant fields, method parameters, and return values
- Inline methods that are short or only called once
- Simplify tail recursion calls
- Merge classes and interfaces
- Make methods private, static, and final when possible
- Make classes static and final when possible
- Replace interfaces that have single implementations
- Variable peephole optimizations
- Arithmetic peephole optimizations, like replacing ...*2 by ... << 1
- Remove local variables
- Branch peephole optimization
- Remove unused classes and class elements
- Moving constant expressions out of loops
- Static method inlining
- Virtual method inlining
- Flow analysis
- stack analysis
- BC verifications:
  - Known instructions
  - Valid jump addresses
  - Jumps to the same address should have allways the same (valid) stack
  - Valid referenced pool data
  - Class cannot subclass a sealed class
  - No creating of a new instance of an abstract class
- INVOKE of known method may reference method from class table by an index
- inlining of VIRTUAL_INVOKE calls and of INTERFACE_INVOKE calls (inline several methods withing the call and resolve by instance at run)
- translate INSTR_NEW as createInstance call
- Escape analysis to allocated object on Stack instead of Heap (Especially value types)
- use ASSIGN_THIS and LOAD_THIS

připomínky:
- dědění od objectu by mělo být v classfile & bytecode
- v bc volat kontruktory pro Object, vm toto volání odstraní

Kompilátor:
- maxstack
- utf-8 stringy
- null
- push_char je jen 8bit

GC:
- set child (use in PolymorphicCache::init)

changes: