Use run-time tablesNextToCode in compiler exclusively (#15548)wip/D5082

Summary:

 - There is no more use of the TABLES_NEXT_TO_CODE CPP macro in
   `compiler/`. GHCI_TABLES_NEXT_TO_CODE is also removed entirely.
   The field within `PlatformMisc` within `DynFlags` is used instead.

 - The field is still not exposed as a CLI flag. We might consider some
   way to ensure the right RTS / libraries are used before doing that.

Original reviewers:

Original subscribers: TerrorJack, rwbarton, carter

Original Differential Revision: https://phabricator.haskell.org/D5082

1 files changed, 67 insertions, 71 deletions

diff --git a/libraries/ghci/GHCi/InfoTable.hsc b/libraries/ghci/GHCi/InfoTable.hsc
index ab13485e28..4886577d6e 100644
--- a/libraries/ghci/GHCi/InfoTable.hsc
+++ b/libraries/ghci/GHCi/InfoTable.hsc
@@ -13,27 +13,23 @@ module GHCi.InfoTable
     mkConInfoTable
   ) where
 
-import Prelude -- See note [Why do we import Prelude here?]
+import Prelude hiding (fail) -- See note [Why do we import Prelude here?]
+
 import Foreign
 import Foreign.C
 import GHC.Ptr
 import GHC.Exts
 import GHC.Exts.Heap
 import Data.ByteString (ByteString)
+import Control.Monad.Fail
 import qualified Data.ByteString as BS
 
-ghciTablesNextToCode :: Bool
-#if defined(TABLES_NEXT_TO_CODE)
-ghciTablesNextToCode = True
-#else
-ghciTablesNextToCode = False
-#endif
-
 -- NOTE: Must return a pointer acceptable for use in the header of a closure.
 -- If tables_next_to_code is enabled, then it must point the the 'code' field.
 -- Otherwise, it should point to the start of the StgInfoTable.
 mkConInfoTable
-   :: Int     -- ptr words
+   :: Bool    -- TABLES_NEXT_TO_CODE
+   -> Int     -- ptr words
    -> Int     -- non-ptr words
    -> Int     -- constr tag
    -> Int     -- pointer tag
@@ -42,23 +38,23 @@ mkConInfoTable
       -- resulting info table is allocated with allocateExec(), and
       -- should be freed with freeExec().
 
-mkConInfoTable ptr_words nonptr_words tag ptrtag con_desc =
-  castFunPtrToPtr <$> newExecConItbl itbl con_desc
-  where
-     entry_addr = interpConstrEntry !! ptrtag
-     code' = mkJumpToAddr entry_addr
+mkConInfoTable tables_next_to_code ptr_words nonptr_words tag ptrtag con_desc = do
+  let entry_addr = interpConstrEntry !! ptrtag
+  code' <- if tables_next_to_code
+    then Just <$> mkJumpToAddr entry_addr
+    else pure Nothing
+  let
      itbl  = StgInfoTable {
-                 entry = if ghciTablesNextToCode
+                 entry = if tables_next_to_code
                          then Nothing
                          else Just entry_addr,
                  ptrs  = fromIntegral ptr_words,
                  nptrs = fromIntegral nonptr_words,
                  tipe  = CONSTR,
                  srtlen = fromIntegral tag,
-                 code  = if ghciTablesNextToCode
-                         then Just code'
-                         else Nothing
+                 code  = code'
               }
+  castFunPtrToPtr <$> newExecConItbl tables_next_to_code itbl con_desc
 
 
 -- -----------------------------------------------------------------------------
@@ -76,39 +72,46 @@ data Arch = ArchSPARC
           | ArchARM64
           | ArchPPC64
           | ArchPPC64LE
-          | ArchUnknown
  deriving Show
 
-platform :: Arch
-platform =
+mkJumpToAddr :: MonadFail m => EntryFunPtr-> m ItblCodes
+mkJumpToAddr ptr = do
+  arch <- case mArch of
+    Just a -> pure a
+    Nothing ->
+      -- This code must not be called. You either need to add your
+      -- architecture as a distinct case to 'Arch' and 'mArch', or use
+      -- non-TABLES_NEXT_TO_CODE mode.
+      fail "mkJumpToAddr: Unknown obscure arch is not supported with TABLES_NEXT_TO_CODE"
+  pure $ mkJumpToAddr' arch ptr
+
+-- | 'Just' if it's a known OS, or 'Nothing' otherwise.
+mArch :: Maybe Arch
+mArch =
 #if defined(sparc_HOST_ARCH)
-       ArchSPARC
+       Just ArchSPARC
 #elif defined(powerpc_HOST_ARCH)
-       ArchPPC
+       Just ArchPPC
 #elif defined(i386_HOST_ARCH)
-       ArchX86
+       Just ArchX86
 #elif defined(x86_64_HOST_ARCH)
-       ArchX86_64
+       Just ArchX86_64
 #elif defined(alpha_HOST_ARCH)
-       ArchAlpha
+       Just ArchAlpha
 #elif defined(arm_HOST_ARCH)
-       ArchARM
+       Just ArchARM
 #elif defined(aarch64_HOST_ARCH)
-       ArchARM64
+       Just ArchARM64
 #elif defined(powerpc64_HOST_ARCH)
-       ArchPPC64
+       Just ArchPPC64
 #elif defined(powerpc64le_HOST_ARCH)
-       ArchPPC64LE
+       Just ArchPPC64LE
 #else
-#    if defined(TABLES_NEXT_TO_CODE)
-#        error Unimplemented architecture
-#    else
-       ArchUnknown
-#    endif
+       Nothing
 #endif
 
-mkJumpToAddr :: EntryFunPtr -> ItblCodes
-mkJumpToAddr a = case platform of
+mkJumpToAddr' :: Arch -> EntryFunPtr -> ItblCodes
+mkJumpToAddr' platform a = case platform of
     ArchSPARC ->
         -- After some consideration, we'll try this, where
         -- 0x55555555 stands in for the address to jump to.
@@ -268,11 +271,6 @@ mkJumpToAddr a = case platform of
                    0x618C0000 .|. lo16 w32,
                    0x7D8903A6, 0x4E800420 ]
 
-    -- This code must not be called. You either need to
-    -- add your architecture as a distinct case or
-    -- use non-TABLES_NEXT_TO_CODE mode
-    ArchUnknown -> error "mkJumpToAddr: ArchUnknown is unsupported"
-
 byte0 :: (Integral w) => w -> Word8
 byte0 w = fromIntegral w
 
@@ -316,38 +314,40 @@ data StgConInfoTable = StgConInfoTable {
 
 
 pokeConItbl
-  :: Ptr StgConInfoTable -> Ptr StgConInfoTable -> StgConInfoTable
+  :: Bool -> Ptr StgConInfoTable -> Ptr StgConInfoTable -> StgConInfoTable
   -> IO ()
-pokeConItbl wr_ptr _ex_ptr itbl = do
-#if defined(TABLES_NEXT_TO_CODE)
-  -- Write the offset to the con_desc from the end of the standard InfoTable
-  -- at the first byte.
-  let con_desc_offset = conDesc itbl `minusPtr` (_ex_ptr `plusPtr` conInfoTableSizeB)
-  (#poke StgConInfoTable, con_desc) wr_ptr con_desc_offset
-#else
-  -- Write the con_desc address after the end of the info table.
-  -- Use itblSize because CPP will not pick up PROFILING when calculating
-  -- the offset.
-  pokeByteOff wr_ptr itblSize (conDesc itbl)
-#endif
+pokeConItbl tables_next_to_code wr_ptr _ex_ptr itbl = do
+  if tables_next_to_code
+  then do
+      -- Write the offset to the con_desc from the end of the standard InfoTable
+      -- at the first byte.
+      let con_desc_offset = conDesc itbl `minusPtr` (_ex_ptr `plusPtr` conInfoTableSizeB)
+      (#poke StgConInfoTable, con_desc) wr_ptr con_desc_offset
+  else do
+      -- Write the con_desc address after the end of the info table.
+      -- Use itblSize because CPP will not pick up PROFILING when calculating
+      -- the offset.
+      pokeByteOff wr_ptr itblSize (conDesc itbl)
   pokeItbl (wr_ptr `plusPtr` (#offset StgConInfoTable, i)) (infoTable itbl)
 
-sizeOfEntryCode :: Int
-sizeOfEntryCode
-  | not ghciTablesNextToCode = 0
-  | otherwise =
-     case mkJumpToAddr undefined of
+sizeOfEntryCode :: MonadFail m => Bool -> m Int
+sizeOfEntryCode tables_next_to_code
+  | not tables_next_to_code = pure 0
+  | otherwise = do
+     code' <- mkJumpToAddr undefined
+     pure $ case code' of
        Left  xs -> sizeOf (head xs) * length xs
        Right xs -> sizeOf (head xs) * length xs
 
 -- Note: Must return proper pointer for use in a closure
-newExecConItbl :: StgInfoTable -> ByteString -> IO (FunPtr ())
-newExecConItbl obj con_desc
+newExecConItbl :: Bool -> StgInfoTable -> ByteString -> IO (FunPtr ())
+newExecConItbl tables_next_to_code obj con_desc
    = alloca $ \pcode -> do
+        sz0 <- sizeOfEntryCode tables_next_to_code
         let lcon_desc = BS.length con_desc + 1{- null terminator -}
             -- SCARY
             -- This size represents the number of bytes in an StgConInfoTable.
-            sz = fromIntegral (conInfoTableSizeB + sizeOfEntryCode)
+            sz = fromIntegral $ conInfoTableSizeB + sz0
                -- Note: we need to allocate the conDesc string next to the info
                -- table, because on a 64-bit platform we reference this string
                -- with a 32-bit offset relative to the info table, so if we
@@ -356,17 +356,13 @@ newExecConItbl obj con_desc
         ex_ptr <- peek pcode
         let cinfo = StgConInfoTable { conDesc = ex_ptr `plusPtr` fromIntegral sz
                                     , infoTable = obj }
-        pokeConItbl wr_ptr ex_ptr cinfo
+        pokeConItbl tables_next_to_code wr_ptr ex_ptr cinfo
         BS.useAsCStringLen con_desc $ \(src, len) ->
             copyBytes (castPtr wr_ptr `plusPtr` fromIntegral sz) src len
-        let null_off = fromIntegral sz + fromIntegral (BS.length con_desc)
-        poke (castPtr wr_ptr `plusPtr` null_off) (0 :: Word8)
         _flushExec sz ex_ptr -- Cache flush (if needed)
-#if defined(TABLES_NEXT_TO_CODE)
-        return (castPtrToFunPtr (ex_ptr `plusPtr` conInfoTableSizeB))
-#else
-        return (castPtrToFunPtr ex_ptr)
-#endif
+        if tables_next_to_code
+          then return (castPtrToFunPtr (ex_ptr `plusPtr` conInfoTableSizeB))
+          else return (castPtrToFunPtr ex_ptr)
 
 foreign import ccall unsafe "allocateExec"
   _allocateExec :: CUInt -> Ptr (Ptr a) -> IO (Ptr a)