#5423: Registers above R8 corrupt when called through prim import
---------------------------------+------------------------------------------
Reporter: pumpkin | Owner:
Type: bug | Status: new
Priority: normal | Component: Compiler
Version: 7.2.1 | Keywords:
Testcase: | Blockedby:
Os: Unknown/Multiple | Blocking:
Architecture: Unknown/Multiple | Failure: None/Unknown
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I write a cmm function:
{{{
primbug
{
foreign "C" printf("%d %d %d %d %d %d %d %d %d\n", R1, R2, R3, R4, R5,
R6, R7, R8, R9);
RET_N(R9);
}
}}}
and a binding to it in Haskell:
{{{
foreign import prim "primbug" primbug :: Int# -> Int# -> Int# -> Int#
-> Int# -> Int# -> Int# -> Int#
-> Int#
-> Int#
-- This should resemble id
bug :: Int -> Int
bug (I# i) = I# (primbug 0# 111# 222# 333# 444# 555# 666# 777# i)
main = print (bug 888)
}}}
and the program outputs:
{{{
0 111 222 333 444 555 666 777 0
0
}}}
The contents of R9 have been lost somehow! The result of this corruption
isn't always 0, if that helps track it down: in my more complicated use
case, I'm getting smallish numbers (two hex digits) instead of a
legitimate pointer.
I'm attaching a small cabal package to help reproduce it, because it's a
pain to build.
--
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/5423>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler
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