When generating C, don't pretend functions are data

We used to generated things like:
    extern StgWordArray (newCAF) __attribute__((aligned (8)));
    ((void (*)(void *))(W_)&newCAF)((void *)R1.w);
(which is to say, pretend that newCAF is some data, then cast it to a
function and call it).
This goes wrong on at least IA64, where:
    A function pointer on the ia64 does not point to the first byte of
    code. Intsead, it points to a structure that describes the function.
    The first quadword in the structure is the address of the first byte
    of code
so we end up dereferencing function pointers one time too many, and
segfaulting.

1 files changed, 11 insertions, 0 deletions

diff --git a/compiler/utils/Binary.hs b/compiler/utils/Binary.hs
index 4f48a424b3..c61f8a6baa 100644
--- a/compiler/utils/Binary.hs
+++ b/compiler/utils/Binary.hs
@@ -67,6 +67,7 @@ import Panic
 import UniqFM
 import FastMutInt
 import Fingerprint
+import BasicTypes
 
 import Foreign
 import Data.Array
@@ -726,3 +727,13 @@ instance Binary Fingerprint where
   put_ h (Fingerprint w1 w2) = do put_ h w1; put_ h w2
   get  h = do w1 <- get h; w2 <- get h; return (Fingerprint w1 w2)
 
+instance Binary FunctionOrData where
+    put_ bh IsFunction = putByte bh 0
+    put_ bh IsData     = putByte bh 1
+    get bh = do
+        h <- getByte bh
+        case h of
+          0 -> return IsFunction
+          1 -> return IsData
+          _ -> panic "Binary FunctionOrData"
+