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author | Sergei Trofimovich <slyfox@gentoo.org> | 2014-09-04 17:50:45 +0300 |
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committer | Sergei Trofimovich <slyfox@gentoo.org> | 2014-09-05 09:46:28 +0300 |
commit | e18525fae273f4c1ad8d6cbe1dea4fc074cac721 (patch) | |
tree | a0a9e538868409fbb2be7609726a023517c60001 | |
parent | 6af1c9b2709281520c2015349e4a15265c364962 (diff) | |
download | haskell-e18525fae273f4c1ad8d6cbe1dea4fc074cac721.tar.gz |
pprC: declare extern cmm primitives as functions, not data
Summary:
The commit fixes incorrect code generation of
integer-gmp package on ia64 due to C prototypes mismatch.
Before the patch prototypes for "foreign import prim" were:
StgWord poizh[];
After the patch they became:
StgFunPtr poizh();
Long story:
Consider the following simple example:
{-# LANGUAGE MagicHash, GHCForeignImportPrim, UnliftedFFITypes #-}
module M where
import GHC.Prim -- Int#
foreign import prim "poizh" poi# :: Int# -> Int#
Before the patch unregisterised build generated the
following 'poizh' reference:
EI_(poizh); /* StgWord poizh[]; */
FN_(M_poizh_entry) {
// ...
JMP_((W_)&poizh);
}
After the patch it looks this way:
EF_(poizh); /* StgFunPtr poizh(); */
FN_(M_poizh_entry) {
// ...
JMP_((W_)&poizh);
}
On ia64 it leads to different relocation types being generated:
incorrect one:
addl r14 = @ltoffx(poizh#)
ld8.mov r14 = [r14], poizh# ; r14 = address-of 'poizh#'
correct one:
addl r14 = @ltoff(@fptr(poizh#)), gp ; r14 = address-of-thunk 'poizh#'
ld8 r14 = [r14]
'@fptr(poizh#)' basically instructs assembler to creates
another obect consisting of real address to 'poizh' instructions
and module address. That '@fptr' object is used as a function "address"
This object is different for every module referencing 'poizh' symbol.
All indirect function calls expect '@fptr' object. That way
call site reads real destination address and set destination
module address in 'gp' register from '@fptr'.
Signed-off-by: Sergei Trofimovich <slyfox@gentoo.org>
-rw-r--r-- | compiler/cmm/CLabel.hs | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/compiler/cmm/CLabel.hs b/compiler/cmm/CLabel.hs index 02ad026249..0f2c0ae7fa 100644 --- a/compiler/cmm/CLabel.hs +++ b/compiler/cmm/CLabel.hs @@ -813,6 +813,7 @@ labelType (CmmLabel _ _ CmmClosure) = GcPtrLabel labelType (CmmLabel _ _ CmmCode) = CodeLabel labelType (CmmLabel _ _ CmmInfo) = DataLabel labelType (CmmLabel _ _ CmmEntry) = CodeLabel +labelType (CmmLabel _ _ CmmPrimCall) = CodeLabel labelType (CmmLabel _ _ CmmRetInfo) = DataLabel labelType (CmmLabel _ _ CmmRet) = CodeLabel labelType (RtsLabel (RtsSelectorInfoTable _ _)) = DataLabel |