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Diffstat (limited to 'compiler/iface/IfaceEnv.lhs')
| -rw-r--r-- | compiler/iface/IfaceEnv.lhs | 20 |
1 files changed, 20 insertions, 0 deletions
diff --git a/compiler/iface/IfaceEnv.lhs b/compiler/iface/IfaceEnv.lhs index 20a21c3733..0441fdbf41 100644 --- a/compiler/iface/IfaceEnv.lhs +++ b/compiler/iface/IfaceEnv.lhs @@ -55,10 +55,27 @@ import Data.IORef ( atomicModifyIORef, readIORef ) %* * %********************************************************* +Note [The Name Cache] +~~~~~~~~~~~~~~~~~~~~~ +The Name Cache makes sure that, during any invovcation of GHC, each +External Name "M.x" has one, and only one globally-agreed Unique. + +* The first time we come across M.x we make up a Unique and record that + association in the Name Cache. + +* When we come across "M.x" again, we look it up in the Name Cache, + and get a hit. + +The functions newGlobalBinder, allocateGlobalBinder do the main work. +When you make an External name, you should probably be calling one +of them. + + \begin{code} newGlobalBinder :: Module -> OccName -> SrcSpan -> TcRnIf a b Name -- Used for source code and interface files, to make the -- Name for a thing, given its Module and OccName +-- See Note [The Name Cache] -- -- The cache may already already have a binding for this thing, -- because we may have seen an occurrence before, but now is the @@ -74,6 +91,7 @@ allocateGlobalBinder :: NameCache -> Module -> OccName -> SrcSpan -> (NameCache, Name) +-- See Note [The Name Cache] allocateGlobalBinder name_supply mod occ loc = case lookupOrigNameCache (nsNames name_supply) mod occ of -- A hit in the cache! We are at the binding site of the name. @@ -171,6 +189,8 @@ lookupOrig mod occ %* * %************************************************************************ +See Note [The Name Cache] above. + \begin{code} lookupOrigNameCache :: OrigNameCache -> Module -> OccName -> Maybe Name lookupOrigNameCache _ mod occ |