Progress report in Pen programming language

October 16, 2022

@raviqqe

Agenda

• Progress report
  • Reflect package
  • Test package improvements
  • C calling convention
  • Compiler optimization
• Next plans

Progress report

Reflect package

• Reflect package is added for reflection.
• By using it, programs can access type information of values at runtime.
• Currently, it has two functions.
  • Debug
    • Type: \(any) string
    • Pretty-prints a value.
  • Equal
    • Type: \(any, any) boolean | none
    • Compares values for partial equality.

Test package

• Assertions functions in the Test package can now pretty-print values on failures.

Test code:

Check = \() none | error {
  Assert'Equal(42, none)
}

Output:

foo.test.pen
        FAIL    Check
                Message: values are not equal (found: 42) (expected: none)
summary
        FAIL    0 passed, 1 failed

C calling convention

• The C calling convention is implemented in the Pen compiler.
  • I couldn't wait for C wrapper emission in MLIR...
• It's based on the System V x86-64 ABI.
  • Many other platforms also have adopted it.
• Many hacks to circumvent a fake C calling convention is removed from the compiler.
  • Variant types are passed on stack instead of heap if necessary.

Compiler optimization

Miscellaneous optimization in the Pen compiler.

• Functional algorithm to imperative for CPS transformation
• Unique names for local variables in F--
• Type compilation cache
• 3x speedup for compiling certain modules

Others

• Everything runs on macOS with M1 chip now.
• Content hash-based rebuilds
  • Implemented in the Turtle build system

Next plan

• More lower-hanging fruits for compiler optimization

Summary

• Progress
  • Reflect package
  • Test package improvements
  • C calling convention
  • Compiler optimization
• Next plans