GHC LLVMBackend Workshop

May 8, 2010Osaka, Japan

Tatsuhiro Ujihisahttp://ujihisa.blogspot.com/

GHC?

•The most common Haskell compiler

•More features than Haskell98 specification

LLVM?

•Low Level Virtual Machine

•A virtual machine for arbitrary environments

•(like JVM for C)

GHC × LLVM

Demo

☜ What I did?

• "fib" app on normal GHC

• "fib" app on LLVM GHC

• benchmarks of them

Differences

•What do they change from and to?

•GHC:

•Haskell -> Executable

•LLVM GHC:

•Haskell -> LLVM Assembly Language

LLVM Assemby Language (1/2)

•Platform-independent Assembly Language

• Infinite number of (virtual) registers

•All registers are referential transparent

LLVM Assemby Language (2/2)

•Can call all C functions

•other features are almost same as other common assembly languages such as IA-32

Advantage?☞ Optimizer!

(to be continued...)