+ where
+
+ {- To find the string in the constructor's info table we need to consider
+ the layout of info tables relative to the entry code for a closure.
+
+ An info table can be next to the entry code for the closure, or it can
+ be separate. The former (faster) is used in registerised versions of ghc,
+ and the latter (portable) is for non-registerised versions.
+
+ The diagrams below show where the string is to be found relative to
+ the normal info table of the closure.
+
+ 1) Code next to table:
+
+ --------------
+ | | <- pointer to the start of the string
+ --------------
+ | | <- the (start of the) info table structure
+ | |
+ | |
+ --------------
+ | entry code |
+ | .... |
+
+ In this case the pointer to the start of the string can be found in
+ the memory location _one word before_ the first entry in the normal info
+ table.
+
+ 2) Code NOT next to table:
+
+ --------------
+ info table structure -> | *------------------> --------------
+ | | | entry code |
+ | | | .... |
+ --------------
+ ptr to start of str -> | |
+ --------------
+
+ In this case the pointer to the start of the string can be found
+ in the memory location: info_table_ptr + info_table_size
+ -}
+
+ getConDescAddress :: Ptr StgInfoTable -> IO (Ptr Word8)
+ getConDescAddress ptr
+ | ghciTablesNextToCode = do
+ offsetToString <- peek $ ptr `plusPtr` (- wORD_SIZE)
+ return $ (ptr `plusPtr` stdInfoTableSizeB) `plusPtr` (fromIntegral (offsetToString :: StgWord))
+ | otherwise =
+ peek $ intPtrToPtr $ (ptrToIntPtr ptr) + fromIntegral stdInfoTableSizeB
+
+ -- parsing names is a little bit fiddly because we have a string in the form:
+ -- pkg:A.B.C.foo, and we want to split it into three parts: ("pkg", "A.B.C", "foo").
+ -- Thus we split at the leftmost colon and the rightmost occurrence of the dot.
+ -- It would be easier if the string was in the form pkg:A.B.C:foo, but alas
+ -- this is not the conventional way of writing Haskell names. We stick with
+ -- convention, even though it makes the parsing code more troublesome.
+ -- Warning: this code assumes that the string is well formed.
+ parse :: [Word8] -> ([Word8], [Word8], [Word8])
+ parse input
+ = ASSERT (all (>0) (map length [pkg, mod, occ])) (pkg, mod, occ)
+ where
+ dot = fromIntegral (ord '.')
+ (pkg, rest1) = break (== fromIntegral (ord ':')) input
+ (mod, occ)
+ = (concat $ intersperse [dot] $ reverse modWords, occWord)
+ where
+ (modWords, occWord) = ASSERT (length rest1 > 0) (parseModOcc [] (tail rest1))
+ parseModOcc :: [[Word8]] -> [Word8] -> ([[Word8]], [Word8])
+ parseModOcc acc str
+ = case break (== dot) str of
+ (top, []) -> (acc, top)
+ (top, _:bot) -> parseModOcc (top : acc) bot
+
+
+getHValue :: HscEnv -> Name -> IO HValue
+getHValue hsc_env name = do
+ when (isExternalName name) $ do
+ ok <- linkDependencies hsc_env noSrcSpan [nameModule name]
+ when (failed ok) $ ghcError (ProgramError "")