StgCmmCon.hs:240 reads
; return (mkRhsInit dflags reg lf_info hp_plus_n) }
what's that got to do with pointer tagging?
But yes we need to do it in both places. Consider
f x xs = let y = x:xs
in g y
We should tag y before passing it to g. That's the StgCmmCon case.
But also we clearly must do so in the entry code for a data constructor
Simon
| -----Original Message-----
| From: ghc-devs [mailto:ghc-devs-bounces@haskell.org] On Behalf Of Ömer
| Sinan Agacan
| Sent: 25 August 2016 11:46
| To: ghc-devs
| Subject: Can we mark DataCon ptrs only in allocation sites and not
| generate entry code?
|
| As far as I can see in the native code compiler we mark DataCon
| pointers in two places:
|
| 1. In allocation sites (StgCmmCon.hs:240)
| 2. In DataCon entry code (StgCmm.hs:244)
|
| I was wondering why we can't get away with just doing (1). Can anyone
| give me
| an example where an allocation doesn't return a tagged pointer and we
| need to
| tag it in entry code? If every allocation returns a tagged pointer,
| then why do
| we need (2) ?
|
| Thanks
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