[Git][ghc/ghc][master] 2 commits: Force in_multi to avoid retaining entire hsc_env

[Marge Bot (@marge-bot)]

Marge Bot pushed to branch master at Glasgow Haskell Compiler / GHC


Commits:
c6def949 by Matthew Pickering at 2024-04-08T16:06:51-04:00
Force in_multi to avoid retaining entire hsc_env

- - - - -
fbb91a63 by Fendor at 2024-04-08T16:06:51-04:00
Eliminate name thunk in declaration fingerprinting

Thunk analysis showed that we have about 100_000 thunks (in agda and
`-fwrite-simplified-core`) pointing to the name of the name decl.
Forcing this thunk fixes this issue.

The thunk created here is retained by the thunk created by forkM, it is
better to eagerly force this because the result (a `Name`) is already
retained indirectly via the `IfaceDecl`.

- - - - -


2 changed files:

- compiler/GHC/IfaceToCore.hs
- ghc/GHCi/UI.hs


Changes:

=====================================
compiler/GHC/IfaceToCore.hs
=====================================
@@ -956,7 +956,9 @@ tc_iface_decl_fingerprint :: Bool                    -- Don't load pragmas into
 tc_iface_decl_fingerprint ignore_prags (_version, decl)
   = do  {       -- Populate the name cache with final versions of all
                 -- the names associated with the decl
-          let main_name = ifName decl
+          let !main_name = ifName decl
+                -- Force this field access, as `main_name` thunk will otherwise
+                -- be retained in the thunk created by `forkM`.
 
         -- Typecheck the thing, lazily
         -- NB. Firstly, the laziness is there in case we never need the


=====================================
ghc/GHCi/UI.hs
=====================================
@@ -557,7 +557,8 @@ interactiveUI config srcs maybe_exprs = do
            -- Set to True because Prelude is implicitly imported.
            impDecl at ImportDecl{ideclExt=ext} -> impDecl{ideclExt = ext{ideclImplicit=True}}
    hsc_env <- GHC.getSession
-   let in_multi = length (hsc_all_home_unit_ids hsc_env) > 1
+   let !in_multi = length (hsc_all_home_unit_ids hsc_env) > 1
+        -- We force this to make sure we don't retain the hsc_env when reloading
    empty_cache <- liftIO newIfaceCache
    startGHCi (runGHCi srcs maybe_exprs)
         GHCiState{ progname           = default_progname,



View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/f2cc1107790d42fee1a11d5b16bc282d31ea6f78...fbb91a6371308fffca926f0ab45ae0a14e7c6847

-- 
View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/f2cc1107790d42fee1a11d5b16bc282d31ea6f78...fbb91a6371308fffca926f0ab45ae0a14e7c6847
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