Historical page

This page is a bunch of notes on the new code generator. It is outdated and is here only for historical reasons.It should probably be removed. See Code Generator page for a description of current code generator.

Cleanup after the new codegen is enabled

The new codegen was enabled by default in 832077ca5393d298324cb6b0a2cb501e27209768. Now that the switch has been made, we can remove all the cruft associated with the old code generator. There are dependencies between some of the components, so we have to do things in the right order. Here is a list of the cleanup tasks, and notes about dependencies:

Independent tasks

  • Use BlockId or Label consistently, currently we use a mixture of the two. Maybe get rid of the BlockId module.
  • Remove live-var and CAF lists from StgSyn, and then clean up CoreToStg
  • DONE Remove the SRT pass in simplStg/SRT.lhs
  • DONE remove RET_DYN from the RTS
  • DONE remove -fnew-codegen, related HscMain bits and the CodeGen module.
  • DONE remove CmmOpt.cmmMiniInline, it is not used any more
  • Fix the layering: cmm modules should not depend on codeGen/StgCmm*

Towards removing codeGen/Cg*

  • DONE CmmParse should produce new Cmm.
    • We will probably want two kinds of .cmm file, one that is to be fed through CmmLayoutStack and one that isn't.
    • primops will be fed through CmmLayoutStack, and will use the native calling convention, with the code generator inserting the copyin/copyout for us.
  • DONE Remove all the Cg* modules

Towards removing OldCmm

  • IN PROGRESS (Simon M): Change the NCG over to consume new Cmm. We possibly also want the generated native code to use the Hoopl Block representation, although that will mean changing branch instructions to have both true and false targets, rather than true and fallthrough as we have now.
  • Remove cmm/CmmCvt (this will save some compile-time too)
  • Remove cmm/OldCmm*, cmm/PprOldCmm etc.


  • Do the new SRT story (ToDo: write a wiki page about this)
Last modified 6 years ago Last modified on Feb 1, 2014 1:29:18 PM