Simon, Sorry if I'm too stupid, but do you mean we only support 64-bit results from "prim" call? But I'm using TO_W_ macro to convert the result to 64-bit value before returning from cmm function. Or you mean result from "ccall" call? nativeGen/X86/CodeGen.hs:genCCall64 definitely supports that. And it works for unsafe "ccall". Looks like the issue is somewhere in translation from high level cmm to low level cmm. Thanks, Yuras On Fri, 2014-06-20 at 21:24 +0100, Simon Marlow wrote:

On 20/06/14 15:03, Yuras Shumovich wrote:

...

Hello,

I'm trying to do safe ccall from cmm (see below for the code). It seems to work, but -dcmm-lint is not satisfied:

/opt/ghc-7.8.2/bin/ghc --make -o test hs.hs cmm.cmm c.c -dcmm-lint -fforce-recomp Cmm lint error: in basic block c4 in assignment: _c1::I32 = R1; Reg ty: I32 Rhs ty: I64 Program was: {offset c5: _c0::I64 = R1; _c2::I64 = c_test; _c3::I32 = %MO_UU_Conv_W64_W32(_c0::I64); I64[(young<c4> + 8)] = c4; foreign call "ccall" arg hints: [] result hints: [] (_c2::I64)(...) returns to c4 args: ([_c3::I32]) ress: ([_c1::I32])ret_args: 8ret_off: 8; c4: _c1::I32 = R1; R1 = %MO_SS_Conv_W32_W64(_c1::I32); call (P64[(old + 8)])(R1) args: 8, res: 0, upd: 8; }

<no location info>: Compilation had errors

I believe we only support 64-bit results on a 64-bit platform, but we you can always narrow to 32 bits with an MO_Conv afterwards if you want. This is essentially what happens when you call a function that returns CInt using the FFI - you can always try that and see what Cmm you get.

Also, I'll be mildly surprised if using safe foreign calls from hand-written Cmm works, since I don't believe we use them anywhere so it isn't likely to be well tested :-)

Cheers, Simon

...

The same code without "safe" annotation passes cmm lint. Is it my error or ghc bug? How can I do safe ccall in cmm correctly?

Here is the code:

== c.c == #include

int c_test(int i) { assert(i == 1); return 2; }

== cmm.cmm #include "Cmm.h"

cmm_test(W_ i) { CInt i1; (i1) = ccall c_test(W_TO_INT(i)) "safe"; return (TO_W_(i1)); }

== hs.hs == {-# LANGUAGE GHCForeignImportPrim #-} {-# LANGUAGE ForeignFunctionInterface #-} {-# LANGUAGE MagicHash #-} {-# LANGUAGE UnboxedTuples #-} {-# LANGUAGE UnliftedFFITypes #-}

import GHC.Prim import GHC.Types import Control.Exception

foreign import prim "cmm_test" test :: Int# -> Int#

main :: IO () main = do let i1 = test 1# assert (I# i1 == 2) (return ())

Thanks, Yuras

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I'm not following this thread, but is it worth a ticket? Or better user manual documentation? Or something? Simon | -----Original Message----- | From: ghc-devs [mailto:ghc-devs-bounces@haskell.org] On Behalf Of Simon | Marlow | Sent: 20 June 2014 21:25 | To: Yuras Shumovich; ghc-devs@haskell.org | Subject: Re: CmmLint error when doing safe ccall from cmm | | On 20/06/14 15:03, Yuras Shumovich wrote: | > Hello, | > | > I'm trying to do safe ccall from cmm (see below for the code). It | > seems to work, but -dcmm-lint is not satisfied: | > | > /opt/ghc-7.8.2/bin/ghc --make -o test hs.hs cmm.cmm c.c -dcmm-lint | > -fforce-recomp Cmm lint error: | > in basic block c4 | > in assignment: | > _c1::I32 = R1; | > Reg ty: I32 | > Rhs ty: I64 | > Program was: | > {offset | > c5: _c0::I64 = R1; | > _c2::I64 = c_test; | > _c3::I32 = %MO_UU_Conv_W64_W32(_c0::I64); | > I64[(young<c4> + 8)] = c4; | > foreign call "ccall" arg hints: [] result hints: [] | (_c2::I64)(...) returns to c4 args: ([_c3::I32]) ress: | ([_c1::I32])ret_args: 8ret_off: 8; | > c4: _c1::I32 = R1; | > R1 = %MO_SS_Conv_W32_W64(_c1::I32); | > call (P64[(old + 8)])(R1) args: 8, res: 0, upd: 8; | > } | > | > <no location info>: | > Compilation had errors | | I believe we only support 64-bit results on a 64-bit platform, but we | you can always narrow to 32 bits with an MO_Conv afterwards if you want. | This is essentially what happens when you call a function that returns | CInt using the FFI - you can always try that and see what Cmm you get. | | Also, I'll be mildly surprised if using safe foreign calls from hand- | written Cmm works, since I don't believe we use them anywhere so it | isn't likely to be well tested :-) | | Cheers, | Simon | | | > The same code without "safe" annotation passes cmm lint. Is it my | > error or ghc bug? How can I do safe ccall in cmm correctly? | > | > Here is the code: | > | > == c.c == | > #include | > | > int c_test(int i) | > { | > assert(i == 1); | > return 2; | > } | > | > == cmm.cmm | > #include "Cmm.h" | > | > cmm_test(W_ i) | > { | > CInt i1; | > (i1) = ccall c_test(W_TO_INT(i)) "safe"; | > return (TO_W_(i1)); | > } | > | > == hs.hs == | > {-# LANGUAGE GHCForeignImportPrim #-} | > {-# LANGUAGE ForeignFunctionInterface #-} {-# LANGUAGE MagicHash #-} | > {-# LANGUAGE UnboxedTuples #-} {-# LANGUAGE UnliftedFFITypes #-} | > | > import GHC.Prim | > import GHC.Types | > import Control.Exception | > | > foreign import prim "cmm_test" test :: Int# -> Int# | > | > main :: IO () | > main = do | > let i1 = test 1# | > assert (I# i1 == 2) (return ()) | > | > | > Thanks, | > Yuras | > | > | > _______________________________________________ | > ghc-devs mailing list | > ghc-devs@haskell.org | > http://www.haskell.org/mailman/listinfo/ghc-devs | > | | _______________________________________________ | ghc-devs mailing list | ghc-devs@haskell.org | http://www.haskell.org/mailman/listinfo/ghc-devs