#1424: Argument corruption in FFI with many arguments (maybe 64-bit related)
-----------------------------+----------------------------------------------
Reporter: guest | Owner:
Type: bug | Status: new
Priority: normal | Milestone:
Component: Compiler (FFI) | Version: 6.6.1
Severity: normal | Keywords: ffi
Difficulty: Unknown | Os: Linux
Testcase: | Architecture: x86_64 (amd64)
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With many arguments, something strange occurs in argument passing with
FFI. The misbehaviour only occurs on my 64-bit machine; the program works
correctly on my 32-bit one. It seems as though an extra value is inserted
into the argument list.
First, here is the code. There's a foreign function that takes 10
doubles.
----
{{{
[EMAIL PROTECTED]:~/dev/haskell/ffi$ cat c.c
fC (double a,
double b,
double c,
double d,
double e,
double f,
double g,
double h,
double i,
double j)
{
printf("%f %f %f %f %f %f %f %f %f %f\n", a,b,c,d,e,f,g,h,i,j);
}
[EMAIL PROTECTED]:~/dev/haskell/ffi$ cat Ffi.hs
{-# OPTIONS_GHC -fglasgow-exts #-}
f :: Double -> Double -> Double -> Double -> Double -> Double -> Double ->
Double -> Double -> Double -> IO ()
f a b c d e f g h i j = do
print [a, b, c, d, e, f, g, h, i, j]
fC a b c d e f g h i j
foreign import ccall unsafe "fC" fC ::
Double -> Double -> Double
-> Double -> Double -> Double
-> Double -> Double -> Double -> Double -> IO ()
main = do
f 1 2 3 4 5 6 7 8 9 10
}}}
----
Here is the correct behaviour, on my 32-bit machine. The important output
is the line starting with "1.000000 2.000000 3.00[...]"
----
{{{
[EMAIL PROTECTED]:~/tmp/ffi$ gcc -c c.c
c.c: In function ‘fC’:
c.c:12: warning: incompatible implicit declaration of built-in function
‘printf’
[EMAIL PROTECTED]:~/tmp/ffi$ ghc --make Ffi c.o
[1 of 1] Compiling Main ( Ffi.hs, Ffi.o )
Linking Ffi ...
./[EMAIL PROTECTED]:~/tmp/ffi$ ./Ffi
[1.0,2.0,3.0,4.0,5.0,6.0,7.0,8.0,9.0,10.0]
1.000000 2.000000 3.000000 4.000000 5.000000 6.000000 7.000000 8.000000
9.000000 10.000000
[EMAIL PROTECTED]:~/tmp/ffi$ ghc -v
Glasgow Haskell Compiler, Version 6.6.1, for Haskell 98, compiled by GHC
version 6.6.1
Using package config file: /usr/lib/ghc-6.6.1/package.conf
Using package config file: /home/chris/.ghc/i386-linux-6.6.1/package.conf
wired-in package base mapped to base-2.1.1
wired-in package rts mapped to rts-1.0
wired-in package haskell98 mapped to haskell98-1.0
wired-in package template-haskell mapped to template-haskell-2.1
Hsc static flags: -static
*** Deleting temp files:
Deleting:
*** Deleting temp dirs:
Deleting:
ghc-6.6.1: no input files
Usage: For basic information, try the `--help' option.
[EMAIL PROTECTED]:~/tmp/ffi$ gcc -v
Using built-in specs.
Target: i486-linux-gnu
Configured with: ../src/configure -v --enable-
languages=c,c++,fortran,objc,obj-c++,treelang --prefix=/usr --enable-
shared --with-system-zlib --libexecdir=/usr/lib --without-included-gettext
--enable-threads=posix --enable-nls --with-gxx-include-
dir=/usr/include/c++/4.1.3 --program-suffix=-4.1 --enable-__cxa_atexit
--enable-clocale=gnu --enable-libstdcxx-debug --enable-mpfr --with-
tune=i686 --enable-checking=release i486-linux-gnu
Thread model: posix
gcc version 4.1.3 20070601 (prerelease) (Debian 4.1.2-12)
}}}
----
Here is the bad behaviour, on my 64-bit machine. Note that the Haskell
list has the values [1..10], but the C arguments are 1,2,3,4,5,6,7,8,0,9
(a zero is inserted between 8 and 9).
----
{{{
[EMAIL PROTECTED]:~/dev/haskell/ffi$ gcc -c c.c
c.c: In function ‘fC’:
c.c:12: warning: incompatible implicit declaration of built-in function
‘printf’
[EMAIL PROTECTED]:~/dev/haskell/ffi$ ghc --make Ffi c.o
[1 of 1] Compiling Main ( Ffi.hs, Ffi.o )
Linking Ffi ...
[EMAIL PROTECTED]:~/dev/haskell/ffi$ ./Ffi
[1.0,2.0,3.0,4.0,5.0,6.0,7.0,8.0,9.0,10.0]
1.000000 2.000000 3.000000 4.000000 5.000000 6.000000 7.000000 8.000000
0.000000 9.000000
[EMAIL PROTECTED]:~/dev/haskell/ffi$ ghc -v
Glasgow Haskell Compiler, Version 6.6.1, for Haskell 98, compiled by GHC
version 6.6.1
Using package config file: /usr/lib/ghc-6.6.1/package.conf
Using package config file: /home/chris/.ghc/x86_64-
linux-6.6.1/package.conf
wired-in package base mapped to base-2.1.1
wired-in package rts mapped to rts-1.0
wired-in package haskell98 mapped to haskell98-1.0
wired-in package template-haskell mapped to template-haskell-2.1
Hsc static flags: -static
*** Deleting temp files:
Deleting:
*** Deleting temp dirs:
Deleting:
ghc-6.6.1: no input files
Usage: For basic information, try the `--help' option.
[EMAIL PROTECTED]:~/dev/haskell/ffi$ gcc -v
Using built-in specs.
Target: x86_64-linux-gnu
Configured with: ../src/configure -v --enable-
languages=c,c++,fortran,objc,obj-c++,treelang --prefix=/usr --enable-
shared --with-system-zlib --libexecdir=/usr/lib --without-included-gettext
--enable-threads=posix --enable-nls --with-gxx-include-
dir=/usr/include/c++/4.1.3 --program-suffix=-4.1 --enable-__cxa_atexit
--enable-clocale=gnu --enable-libstdcxx-debug --enable-mpfr --enable-
checking=release x86_64-linux-gnu
Thread model: posix
gcc version 4.1.3 20070429 (prerelease) (Debian 4.1.2-5)
}}}
--
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/1424>
GHC <http://www.haskell.org/ghc/>
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