Comments, layout and cmm-notes

...all to do with the new codgen path

1 files changed, 38 insertions, 0 deletions

diff --git a/compiler/cmm/cmm-notes b/compiler/cmm/cmm-notes
index c0ccadfbec..98c2e83699 100644
--- a/compiler/cmm/cmm-notes
+++ b/compiler/cmm/cmm-notes
@@ -1,3 +1,41 @@
+More notes (June 11)

+~~~~~~~~~~~~~~~~~~~~

+* Kill dead code assignArguments, argumentsSize in CmmCallConv.

+  Bake in ByteOff to ParamLocation and ArgumentFormat

+  CmmActuals -> [CmmActual]  similary CmmFormals

+

+* Possible refactoring: Nuke AGraph in favour of 

+      mkIfThenElse :: Expr -> Graph -> Graph -> FCode Graph

+  or even

+      mkIfThenElse :: HasUniques m => Expr -> Graph -> Graph -> m Graph

+  (Remmber that the .cmm file parser must use this function)

+

+  or parameterise FCode over its envt; the CgState part seem useful for both

+

+* Move top and tail calls to runCmmContFlowOpts from HscMain to CmmCps.cpsTop

+  (and rename the latter!)

+

+* "Remove redundant reloads" in CmmSpillReload should be redundant; since

+  insertLateReloads is now gone, every reload is reloading a live variable.

+  Test and nuke.

+

+* Sink and inline S(RegSlot(x)) = e in precisely the same way that we

+  sink and inline x = e

+

+* Stack layout is very like register assignment: find non-conflicting assigments.

+  In particular we can use colouring or linear scan (etc).

+

+  We'd fine-grain interference (on a word by word basis) to get maximum overlap.

+  But that may make very big interference graphs.  So linear scan might be

+  more attactive.

+

+  NB: linear scan does on-the-fly live range splitting.

+

+* When stubbing dead slots be careful not to write into an area that

+  overlaps with an area that's in use.  So stubbing needs to *follow* 

+  stack layout.

+

+

 More notes (May 11)

 ~~~~~~~~~~~~~~~~~~~

 In CmmNode, consider spliting CmmCall into two: call and jump