diff options
| author | Bartosz Nitka <niteria@gmail.com> | 2018-01-05 15:20:05 +0000 |
|---|---|---|
| committer | Bartosz Nitka <niteria@gmail.com> | 2018-01-10 13:50:56 +0000 |
| commit | dbdf77d92c9cd0bbb269137de0bf8754573cdc1e (patch) | |
| tree | 17bbe7fb388308615ba009e4f887c719c9e58107 /compiler/iface/TcIface.hs | |
| parent | 1577908f2a9db0fcf6f749d40dd75481015f5497 (diff) | |
| download | haskell-dbdf77d92c9cd0bbb269137de0bf8754573cdc1e.tar.gz | |
Lift constructor tag allocation out of a loop
Before this change, for each constructor that we want
to allocate a tag for we would traverse a list of all
the constructors in a datatype to determine which tag
a constructor should get.
This is obviously quadratic and for datatypes with 10k
constructors it actually makes a big difference.
This change implements the plan outlined by @simonpj in
https://mail.haskell.org/pipermail/ghc-devs/2017-October/014974.html
which is basically about using a map and constructing it outside the
loop.
One place where things got a bit awkward was TysWiredIn.hs,
it would have been possible to just assign the tags by hand, but
that seemed error-prone to me, so I decided to go through a map
there as well.
Test Plan:
./validate
On a file with 10k constructors
Before:
8,130,522,344 bytes allocated in the heap
Total time 3.682s ( 3.920s elapsed)
After:
4,133,478,744 bytes allocated in the heap
Total time 2.509s ( 2.750s elapsed)
Reviewers: simonpj, bgamari
Reviewed By: simonpj
Subscribers: goldfire, rwbarton, thomie, simonmar, carter, simonpj
GHC Trac Issues: #14657
Differential Revision: https://phabricator.haskell.org/D4289
Diffstat (limited to 'compiler/iface/TcIface.hs')
| -rw-r--r-- | compiler/iface/TcIface.hs | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/compiler/iface/TcIface.hs b/compiler/iface/TcIface.hs index 6fad8da87c..70438f6337 100644 --- a/compiler/iface/TcIface.hs +++ b/compiler/iface/TcIface.hs @@ -897,6 +897,9 @@ tcIfaceDataCons tycon_name tycon tc_tybinders if_cons univ_tvs :: [TyVar] univ_tvs = binderVars (tyConTyVarBinders tc_tybinders) + tag_map :: NameEnv ConTag + tag_map = mkTyConTagMap tycon + tc_con_decl (IfCon { ifConInfix = is_infix, ifConExTvs = ex_bndrs, ifConUserTvBinders = user_bndrs, @@ -960,7 +963,7 @@ tcIfaceDataCons tycon_name tycon tc_tybinders if_cons lbl_names univ_tvs ex_tvs user_tv_bndrs eq_spec theta - arg_tys orig_res_ty tycon + arg_tys orig_res_ty tycon tag_map ; traceIf (text "Done interface-file tc_con_decl" <+> ppr dc_name) ; return con } mk_doc con_name = text "Constructor" <+> ppr con_name |