From a05bd2872d01a41991fdb35f9431e0c54efaa8fb Mon Sep 17 00:00:00 2001
From: Cheng Shao <terrorjack@type.dance>
Date: Thu, 13 Feb 2025 23:43:10 +0000
Subject: [PATCH] compiler: avoid overwriting existing writers in putWithTables
This patch makes `putWithTables` avoid overwriting all existing
UserData writers in the handle. This is crucial for GHC API users that
use putWithUserData/getWithUserData for serialization logic that
involve Names.
(cherry picked from commit c331eebf575221ed8c67ca232bac4ae047b794a3)
---
compiler/GHC/Iface/Binary.hs | 28 +++++++++++++++-------------
1 file changed, 15 insertions(+), 13 deletions(-)
diff --git a/compiler/GHC/Iface/Binary.hs b/compiler/GHC/Iface/Binary.hs
index 94ebbad34c3..25739f77fc5 100644
--- a/compiler/GHC/Iface/Binary.hs
+++ b/compiler/GHC/Iface/Binary.hs
@@ -43,7 +43,6 @@ import GHC.Types.Unique.FM
import GHC.Utils.Panic
import GHC.Utils.Binary as Binary
import GHC.Data.FastMutInt
-import GHC.Data.FastString (FastString)
import GHC.Types.Unique
import GHC.Utils.Outputable
import GHC.Types.Name.Cache
@@ -321,18 +320,21 @@ putWithTables compressionLevel bh' put_payload = do
(ifaceType_wt, ifaceTypeWriter) <- initWriteIfaceType compressionLevel
-- Initialise the 'WriterUserData'.
- let writerUserData = mkWriterUserData
- [ mkSomeBinaryWriter @FastString fsWriter
- , mkSomeBinaryWriter @Name nameWriter
- -- We sometimes serialise binding and non-binding names differently, but
- -- not during 'ModIface' serialisation. Here, we serialise both to the same
- -- deduplication table.
- --
- -- See Note [Binary UserData]
- , mkSomeBinaryWriter @BindingName $ mkWriter (\bh name -> putEntry nameWriter bh (getBindingName name))
- , mkSomeBinaryWriter @IfaceType ifaceTypeWriter
- ]
- let bh = setWriterUserData bh' writerUserData
+ --
+ -- Similar to how 'getTables' calls 'addReaderToUserData', here we
+ -- call 'addWriterToUserData' instead of 'setWriterUserData', to
+ -- avoid overwriting existing writers of other types in bh'.
+ let bh =
+ addWriterToUserData fsWriter
+ $ addWriterToUserData nameWriter
+ -- We sometimes serialise binding and non-binding names differently, but
+ -- not during 'ModIface' serialisation. Here, we serialise both to the same
+ -- deduplication table.
+ --
+ -- See Note [Binary UserData]
+ $ addWriterToUserData
+ (mkWriter $ \bh name -> putEntry nameWriter bh $ getBindingName name)
+ $ addWriterToUserData ifaceTypeWriter bh'
([fs_count, name_count, ifacetype_count] , r) <-
-- The order of these entries matters!
--
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