Flite-C: don't bother with the rump object

Furthermore, add some notes and TODOs to the update handling.
tommythorn · Feb 5, 2018 · 8ab9ecb · 8ab9ecb
1 parent 4cf7158
commit 8ab9ecb
Showing 1 changed file with 14 additions and 8 deletions.
diff --git a/flite/Flite/CompileBackend.lhs b/flite/Flite/CompileBackend.lhs
@@ -165,24 165,30 @@ if so, performs an update.
 > , " if (ari <= args)"
 > , " break;"
 > , " assert(usp != ustack);"
 
 We have an AP on the update stack that was evaluated and must be
 updated.
 
 XXX GC can eliminate this indirection, but it looks like we aren't
 doing this (it might require us to mark the indirection as such).
 
 XXX When there's enough space we could overwrite the original AP
 instead of allocating a new AP and installing a redirection.
 
 > , " Node *base = hp;"
 > , " Node *p = usp->s;"
 > , " *hp = makeINT(args 1);"
 > , " while (p < sp) *hp = *p ;"
 > , " *hp = top;"
 
-Install a forwarding pointer to the updated value
 Install a forwarding pointer to the updated value. Note, this will
 leave a "rump" object of the remaining origSize-2 Nodes, but it will
 be compressed out at the next collection.
 
 > , " assert(isINT(usp->h[0]));"
 > , " long origSize = getINT(usp->h[0]);"
 > , " usp->h[0] = makeINT(1);"
 > , " usp->h[1] = makeAP(base);"
-
-XXX This is a little annoying, but I want to keep objects complete.
-However now we can potentially have a zero-sized object.
-
-> , " if (origSize > 1)"
-> , " usp->h[2] = makeINT(origSize - 2);"
 > , " usp--;"
 > , " }"
 > , "}"
@@ -385,7 391,7 @@ A shorthand for a common case
 
 > app :: Locs -> App -> String
 > app vs app = unlines $ header : map (node "*hp " vs) app
-> where header = "*hp = makeINT ("   show (length app)   ");"
 > where header = "*hp = makeINT("   show (length app)   ");"
 
 > spine :: Locs -> App -> String
 > spine vs ns = unlines