New register-based VM and other improvements

[WheretIB]

In this pull request, the previous stack-based VM is completely replaced with a new register-based VM and with many additional changes and improvements:

• Reworked JiT execution engine for new VM with additional optimizations and SSE2 instructions
• JiT support for x64 platform including unwind data for Windows
• Additional code generation optimizations (better load/store aliasing checks, dead store elimination, memory to register promotion)
• External function calls without assembly (support for any platform including Emscripten/WebAssembly)
• Custom file load handler is now paired with custom file data free function
• Visual Studio 2019 solution
• CMake support
• Fixes for translation to C++
• Added std.memory module for work with byte buffers
• std.math vector swizzle functions were moved to std.math_swizzle
• Fixed nested module imports

Language changes:

• Class forward declarations can be imported
• Modules are imported transitively
• Object slicing is prohibited
• Pointers from different classes derived from same base class can be compared

Compiler changes:

• Stability improvements
• Error recovery improvements
• Added 'time-trace' profiler option
• Fixed incorrect constructor call when type name matches a local scope type name
• Fixed array type boxing into 'auto ref' pointer
• Fixed function definitions in unevaluated scopes
• Fixed generic member function calls through 'auto ref' pointers when member function is defined outside the class
• Fixed constructor/assignment calls in member functions defined inside class body
• Fixed 'static if' inside class body
• Fixed short inline functions in function calls through 'auto ref' pointer
• Fixed interactions with 'void' type
• Fixed function lookup in generic function instances
• Fixed ^^ operator overload
• Fixed import of a generic class typedef
• Fixed cases of missing variable initialization
• Fixed missing base class padding in derived classes

ide changes:

• Handle any newline style
• Faster load and code coloring
• Translation to C menu option, save colored IDE buffer to HTML option (documentation)
• Fixed cursor location after undo
• Execution engine selection with debug symbolic evaluation targets

Visual Studio/Code extension changes:

• Type information in function argument list
• Support for direct file references without prior 'didOpen' notification
• Build errors are reported on debugger launch
• Support for error locations originating from different module
• 'auto ref' pointer member display
• Fixed working directory when launched in debugger
• Visual Studio debugger is extended to display nullc call stack, source mapping, locals, watch, assembly (jit), breakpoints (jit), function breakpoints (jit), stepping (jit) (NULLC_EXPORT_EXTERNAL_DEBUGGER_SYMBOLS)

Removed:

• Stack extension/relocation has been removed, added control for stack size reservation (nullcSetExecutorStackSize)

[codecov[bot]]

Codecov Report

Merging #24 into master will decrease coverage by 2.13%. The diff coverage is 85.03%.

@@            Coverage Diff             @@
##           master      #24      +/-   ##
==========================================
- Coverage   86.81%   84.67%   -2.14%     
==========================================
  Files         129      143      +14     
  Lines       31427    42553   +11126     
==========================================
+ Hits        27284    36033    +8749     
- Misses       4143     6520    +2377     

Impacted Files	Coverage Δ
NULLC/CodeGenRegVm_X86.cpp	92.39% <ø> (ø)
NULLC/CodeGen_X86.cpp	88.25% <ø> (ø)
NULLC/Executor_X86.cpp	88.46% <ø> (ø)
NULLC/Executor_X86.h	0.00% <0.00%> (ø)
NULLC/ExpressionTree.cpp	95.30% <ø> (+0.07%)	:arrow_up:
NULLC/InstructionTreeRegVmLower.cpp	91.95% <ø> (ø)
NULLC/InstructionTreeVm.cpp	93.87% <ø> (-2.37%)	:arrow_down:
NULLC/Instruction_X86.cpp	65.51% <ø> (ø)
NULLC/Instruction_X86.h	97.14% <ø> (ø)
NULLC/Linker.cpp	78.50% <ø> (-12.71%)	:arrow_down:
... and 175 more

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