A Look Into the New CTFE Engine

Stefan Koch
May 4 @ 15:30

Duration: 50 minutes
Talk type: Presentation
Level: Intermediate
Slides: ODP
Video

Abstract: 

Two parts: The first is me talking about my experience, writing the engine. The second goes into deeper technical detail explaining the trade-offs, and design decisions.

• What is CTFE and what can it be used for?
• Examples std.regex and sqlite-d.
• Show how the utility of ctfe is not just in the big things but the simple convenience of assigning cos(viewAngle) to a static immutable variable.
• Example: the newCTFE-Engine is ctfeable itself so the compiler itself will not compile if the bytecode-tests fail.
• Discussion of the old Engine, pointing out why it is suboptimal.
• Exposition of different interpretation models:
  • AST-Interpreter.
  • ByteCode-Interpreter (and its extension to JIT).
• Overview: of the newCTFE Codegen-API Explanation of rationale; Backends are pluggable via a template parameter. Showing 2 back-ends BC-Interpreter DebugPrinter-Backend.
• Explaining the design of the BC-Interpreter Showing the 10x performance improvements as a live demo.
• Explanation of the intricacies of Code-Generation. “2 Months of Development. 6 Months of Debugging”.
• Status of what the engine can currently compile.
• Future outlook and showing the 50x Improvement using pseudo-JIT.
• Acknowledgements.

Speaker Bio:

• 25 Years old.
• Programing since the age of 7.
• Begun using D in 2013 while working on the SDC-Compiler.
• Wrote a CTFE reader for Sqlite3-Databases in 2015.
• Working on the new CTFE-Engine and other DMD improvements since July 2016.