[Git][ghc/ghc][wip/seek-bin-off-by-one] Deleted 1 commit: Remove `seekBin` function

Hannes Siebenhandl (@fendor) gitlab at gitlab.haskell.org
Tue Apr 2 07:57:29 UTC 2024



Hannes Siebenhandl pushed to branch wip/seek-bin-off-by-one at Glasgow Haskell Compiler / GHC


WARNING: The push did not contain any new commits, but force pushed to delete the commits and changes below.


Deleted commits:
f7d2f9e1 by Fendor at 2024-04-02T09:45:39+02:00
Remove `seekBin` function

Binary utility `seekBin` used to expand the buffer of the `BinMem`
handle. This is dubious, because the only way to call `seekBin` requires
us use `tellBin`, which always gives us a pointer to already allocated
index. As we don't have a way to reduce the buffer size of the
underlying `BinArray`, there is no way to create an out-of-bounds pointer
for the same `BinArray`.

Thus, it is effectively a bug, if anyone manages to seek to an
out-of-bounds location.
We make this more clear by removing `seekBin` and replacing all
occurrences with `seekBinNoExpand`.

- - - - -


5 changed files:

- compiler/GHC/Iface/Binary.hs
- compiler/GHC/Iface/Ext/Binary.hs
- compiler/GHC/Iface/Ext/Fields.hs
- compiler/GHC/StgToJS/Object.hs
- compiler/GHC/Utils/Binary.hs


Changes:

=====================================
compiler/GHC/Iface/Binary.hs
=====================================
@@ -135,7 +135,7 @@ readBinIface profile name_cache checkHiWay traceBinIface hi_path = do
 
     mod_iface <- getWithUserData name_cache bh
 
-    seekBin bh extFields_p
+    seekBinNoExpand bh extFields_p
     extFields <- get bh
 
     return mod_iface
@@ -191,7 +191,7 @@ writeBinIface profile traceBinIface hi_path mod_iface = do
 
     extFields_p <- tellBin bh
     putAt bh extFields_p_p extFields_p
-    seekBin bh extFields_p
+    seekBinNoExpand bh extFields_p
     put_ bh (mi_ext_fields mod_iface)
 
     -- And send the result to the file


=====================================
compiler/GHC/Iface/Ext/Binary.hs
=====================================
@@ -113,7 +113,7 @@ writeHieFile hie_file_path hiefile = do
   -- write the symtab pointer at the front of the file
   symtab_p <- tellBin bh
   putAt bh symtab_p_p symtab_p
-  seekBin bh symtab_p
+  seekBinNoExpand bh symtab_p
 
   -- write the symbol table itself
   symtab_next' <- readFastMutInt symtab_next
@@ -123,7 +123,7 @@ writeHieFile hie_file_path hiefile = do
   -- write the dictionary pointer at the front of the file
   dict_p <- tellBin bh
   putAt bh dict_p_p dict_p
-  seekBin bh dict_p
+  seekBinNoExpand bh dict_p
 
   -- write the dictionary itself
   dict_next <- readFastMutInt dict_next_ref
@@ -232,17 +232,17 @@ readHieFileContents bh0 name_cache = do
     get_dictionary bin_handle = do
       dict_p <- get bin_handle
       data_p <- tellBin bin_handle
-      seekBin bin_handle dict_p
+      seekBinNoExpand bin_handle dict_p
       dict <- getDictionary bin_handle
-      seekBin bin_handle data_p
+      seekBinNoExpand bin_handle data_p
       return dict
 
     get_symbol_table bh1 = do
       symtab_p <- get bh1
       data_p'  <- tellBin bh1
-      seekBin bh1 symtab_p
+      seekBinNoExpand bh1 symtab_p
       symtab <- getSymbolTable bh1 name_cache
-      seekBin bh1 data_p'
+      seekBinNoExpand bh1 data_p'
       return symtab
 
 putFastString :: HieDictionary -> BinHandle -> FastString -> IO ()


=====================================
compiler/GHC/Iface/Ext/Fields.hs
=====================================
@@ -42,7 +42,7 @@ instance Binary ExtensibleFields where
     forM_ header_entries $ \(field_p_p, dat) -> do
       field_p <- tellBin bh
       putAt bh field_p_p field_p
-      seekBin bh field_p
+      seekBinNoExpand bh field_p
       put_ bh dat
 
   get bh = do
@@ -54,7 +54,7 @@ instance Binary ExtensibleFields where
 
     -- Seek to and get each field's payload:
     fields <- forM header_entries $ \(name, field_p) -> do
-      seekBin bh field_p
+      seekBinNoExpand bh field_p
       dat <- get bh
       return (name, dat)
 


=====================================
compiler/GHC/StgToJS/Object.hs
=====================================
@@ -392,7 +392,7 @@ getObjectBlocks obj bids = mapMaybeM read_entry (zip (objIndex obj) [0..])
     bh = objHandle obj
     read_entry (IndexEntry syms offset,i)
       | IS.member i bids = do
-          seekBin bh offset
+          seekBinNoExpand bh offset
           Just <$> getObjBlock syms bh
       | otherwise = pure Nothing
 


=====================================
compiler/GHC/Utils/Binary.hs
=====================================
@@ -28,9 +28,9 @@ module GHC.Utils.Binary
    unsafeUnpackBinBuffer,
 
    openBinMem,
+   seekBinNoExpand,
 --   closeBin,
 
-   seekBin,
    tellBin,
    castBin,
    withBinBuffer,
@@ -222,10 +222,10 @@ class Binary a where
     put bh a  = do p <- tellBin bh; put_ bh a; return p
 
 putAt  :: Binary a => BinHandle -> Bin a -> a -> IO ()
-putAt bh p x = do seekBin bh p; put_ bh x; return ()
+putAt bh p x = do seekBinNoExpand bh p; put_ bh x; return ()
 
 getAt  :: Binary a => BinHandle -> Bin a -> IO a
-getAt bh p = do seekBin bh p; get bh
+getAt bh p = do seekBinNoExpand bh p; get bh
 
 openBinMem :: Int -> IO BinHandle
 openBinMem size
@@ -240,13 +240,6 @@ openBinMem size
 tellBin :: BinHandle -> IO (Bin a)
 tellBin (BinMem _ r _ _) = do ix <- readFastMutInt r; return (BinPtr ix)
 
-seekBin :: BinHandle -> Bin a -> IO ()
-seekBin h@(BinMem _ ix_r sz_r _) (BinPtr !p) = do
-  sz <- readFastMutInt sz_r
-  if (p > sz)
-        then do expandBin h p; writeFastMutInt ix_r p
-        else writeFastMutInt ix_r p
-
 -- | 'seekBinNoExpand' moves the index pointer to the location pointed to
 -- by 'Bin a'.
 -- This operation may 'panic', if the pointer location is out of bounds of the
@@ -1028,7 +1021,7 @@ lazyPut bh a = do
     put_ bh a           -- dump the object
     q <- tellBin bh     -- q = ptr to after object
     putAt bh pre_a q    -- fill in slot before a with ptr to q
-    seekBin bh q        -- finally carry on writing at q
+    seekBinNoExpand bh q        -- finally carry on writing at q
 
 lazyGet :: Binary a => BinHandle -> IO a
 lazyGet bh = do
@@ -1039,7 +1032,7 @@ lazyGet bh = do
         -- safety.
         off_r <- newFastMutInt 0
         getAt bh { _off_r = off_r } p_a
-    seekBin bh p -- skip over the object for now
+    seekBinNoExpand bh p -- skip over the object for now
     return a
 
 -- | Serialize the constructor strictly but lazily serialize a value inside a



View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/f7d2f9e18e9705cd8e44c903f0129c5d1567d081

-- 
View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/f7d2f9e18e9705cd8e44c903f0129c5d1567d081
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