summaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorSimon Peyton Jones <simonpj@microsoft.com>2011-11-28 05:57:17 +0000
committerSimon Peyton Jones <simonpj@microsoft.com>2011-11-28 05:57:17 +0000
commite8c882790114e152731dd22d89dbda9730e5311f (patch)
treed9c75092c8efb56b287ed8dd7dff8541f761b73a
parent183ae76cb45d7fc8655be1dd83a306a6e1830624 (diff)
downloadhaskell-e8c882790114e152731dd22d89dbda9730e5311f.tar.gz
Remove obslete NOTES file
-rw-r--r--compiler/NOTES156
1 files changed, 0 insertions, 156 deletions
diff --git a/compiler/NOTES b/compiler/NOTES
deleted file mode 100644
index 645d27eaed..0000000000
--- a/compiler/NOTES
+++ /dev/null
@@ -1,156 +0,0 @@
-More type functions
-~~~~~~~~~~~~~~~~~~~
-* Allow {tv = TYPE ty) as a non-rec binding in Core
-* Use this to make equality constraints more uniform
-* Can a Dict can contain an EqPred?
- How does that differ from an EqInst?
-* Make DictBinds into Core
-
-* In zonking, do we need to zonk the kinds of coercion variables?
-
-Type functions
-~~~~~~~~~~~~~~
-* A Given inst should be a CoVar, not a coercion
-
-* finaliseEqInst should not need to call zonk
-
-* Why do we need fromGivenEqDict? How could we construct
- a Dict that had an EqPred?
- newDictBndr should make an EqInst directly
-
-* tc_co should be accessed only inside Inst
-
-* Inst.mkImplicTy needs a commment about filtering out EqInsts
- How *do* we deal with wanted equalities?
-
-* Inst.instType behaves inconsistently for EqInsts: it should
- return an EqPred, like the instType' hack in pprDictsTheta
-
- Consequences: adjust the uses of instType in TcSimplify
-
-* tcDeref* functions are unused, except in tcGenericNormalizeFamInst, when
- we can equally well use TcMType.lookupTcTyVar
-
-* Coercion.mkEqPredCoI looks very peculiar.
-
-
-
-
--------------------------
-*** unexpected failure for jtod_circint(opt)
-
-
- New back end thoughts
-
------------------------------------------------------------------------------
-Codegen notes
-
-* jumps to ImpossibleBranch should be removed.
-
-* Profiling:
- - when updating a closure with an indirection to a function,
- we should make a permanent indirection.
-
- - check that we're bumping the scc count appropriately
-
-* check perf & binary sizes against the HEAD
-
------------------------------------------------------------------------------
-C backend notes
-
-* use STGCALL macros for foreign calls (doesn't look like volatile regs
- are handled properly at the mo).
-
------------------------------------------------------------------------------
-Cmm parser notes
-
-* switches
-
-* need to cater for unexported procedures/info tables?
-
-* We should be able to get rid of entry labels, use info labels only.
- - we need a %ENTRY_LBL(info_lbl) macro, so that instead of
- JMP_(foo_entry) we can write jump %ENTRY_LBL(foo_info).
-
------------------------------------------------------------------------------
-
-* Move arg-descr from LFInfo to ClosureInfo?
- But: only needed for functions
-
-* Move all of CgClosure.link_caf into NewCaf, and newDynCaf
-
-* If the case binder is dead, and the constr is nullary,
- do we need to assign to Node?
-
-
--------------------------------
-NB: all floats are let-binds, but some non-rec lets
- may be unlifted (with RHS ok-for-speculation)
-
-
-simplArg: [use strictness]
- [used for non-top-lvl non-rec RHS or function arg]
- if strict-type || demanded
- simplStrictExpr
- else
- simplExpr ---> (floats,expr)
- float all the floats if exposes constr app, return expr
-
-simpl (applied lambda) ==> simplNonRecBind
-simpl (Let (NonRec ...) ..) ==> simplNonRecBind
-
-simpl (Let (Rec ...) ..) ==> simplRecBind
-
-simplRecBind:
- simplify binders (but not its IdInfo)
- simplify the pairs one at a time
- using simplRecPair
-
-simplNonRecBind: [was simplBeta]
- [used for non-top-lvl non-rec bindings]
- - check for PreInlineUnconditionally
- - simplify binder, including its IdInfo
- - simplArg
- - if strict-type
- addCaseBind [which makes a let if ok-for-spec]
- else
- completeLazyBind
-
-simplLazyBind: [binder already simplified, but not its IdInfo]
- [used for both rec and top-lvl non-rec]
- [must not be strict/unboxed; case not allowed]
- - check for PreInlineUnconditionally
- - substituteIdInfo and add result to in-scope
- [so that rules are available in rec rhs]
- - simplExpr --> (floats,expr)
- - float: lifted floats only
- if exposes constructor or pap (even if non-triv args)
- or if top level
- - completeLazyBind
-
-
-completeLazyBind: [given a simplified RHS]
- [used for both rec and non-rec bindings, top level and not]
- - try discarding dead
- - try PostInlineUnconditionally
- - let-bind coerce arg and repeat
- - try rhs tylam (float)
- - try eta expand (float) [not if any float is unlifted && (non-spec || top_lvl || rec)]
- - let-bind constructor args [not if any float is ..as above..]
-
- - add unfolding [this is the only place we add an unfolding]
- add arity
-
-
-
-
-Eta expansion
-~~~~~~~~~~~~~~
-For eta expansion, we want to catch things like
-
- case e of (a,b) -> \x -> case a of (p,q) -> \y -> r
-
-If the \x was on the RHS of a let, we'd eta expand to bring the two
-lambdas together. And in general that's a good thing to do. Perhaps
-we should eta expand wherever we find a (value) lambda? Then the eta
-expansion at a let RHS can concentrate solely on the PAP case.