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Re: [Mingw-w64-public] 64bit (g)fortran JNI
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From: Hans H. <ha...@2h...> - 2011-04-15 15:47:01
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On 4/15/2011 7:50 AM, Kai Tietz wrote:
> 2011/4/15 Hans Horn<ha...@2h...>:
>> On 4/14/2011 11:25 PM, Kai Tietz wrote:
>>> 2011/4/14 Hans Horn<ha...@2h...>:
>>>> On 4/12/2011 7:25 PM, Jerry DeLisle wrote:
>>>>> On 04/12/2011 07:38 AM, Hans Horn wrote:
>>>>>> Folks,
>>>>>>
>>>>>> has anybody got any experience interfacing (g)fortran routines with
>>>>>> Java via JNI?
>>>>>>
>>>>>> I'm on 64bit Windows7 using cygwin
>>>>>> x86_64-w64-mingw32-gcc and x86_64-w64-mingw32-gfortran, both v4.5.2
>>>>>>
>>>>>> Java: jdk-6u24-windows-x64
>>>>>>
>>>>>> Even though I can statically link the JNI code successfully (using
>>>>>> gfortran as
>>>>>> linker), calling any native method from Java crashes the JVM - even
>>>>>> when no
>>>>>> fortran code is called at all.
>>>>>>
>>>>> What do you mean by native method? Are you trying to call Fortran
>>>>> procedures from Java?
>>>>>
>>>>> In what way does it crash? Can you get a back trace from a debugger?
>>>>>
>>>>> Jerry
>>>>>
>>>>> PS I have no experience with this, just asking some questions to glean
>>>>> additional information. Fortran calling conventions are no exactly the
>>>>> same as C.
>>>>
>>>> Ok,
>>>>
>>>>> What do you mean by native method? Are you trying to call Fortran
>>>>> procedures from Java?
>>>> Nope, via a C wrapper.
>>>>
>>>> I condensed things to the simplest possible testcase that still does not
>>>> function.
>>>> In the process I figured that I needed to link with '-shared'. Without
>>>> that I get said crash of the JVM in both cases, with or without calling
>>>> fortran.
>>>>
>>>>
>>>>
>>>> here's my fortran routine:
>>>> ------------------------------------------------
>>>> subroutine f77sub(string)
>>>> character*(*) string
>>>>
>>>> write(*,*) 'string is ',string
>>>> call fflush(6)
>>>>
>>>> end
>>>>
>>>>
>>>> here's the JNI C wrapper that calls the fortran routine:
>>>> ------------------------------------------------
>>>> #include "JNItest.h"
>>>>
>>>> #ifdef F77SUB
>>>> void f77sub(char*, int);
>>>> #endif
>>>>
>>>> JNIEXPORT void JNICALL Java_JNItest_java2C2f77
>>>> (JNIEnv* env, jclass obj) {
>>>> #ifdef F77SUB
>>>> printf("calling fortran\n"); fflush(stdout);
>>>> f77sub("here is fortran", 15);
>>>> printf("back from fortran\n"); fflush(stdout);
>>>> #else
>>>> printf("not calling fortran at all\n"); fflush(stdout);
>>>> #endif
>>>> }
>>>>
>>>>
>>>> here's my Java class calling the JNI C wrapper:
>>>> ------------------------------------------------
>>>> class JNItest {
>>>> private native void java2C2f77 ();
>>>> static {
>>>> System.loadLibrary("jnitest");
>>>> }
>>>> public static void main (String[] args) {
>>>> new JNItest().java2C2f77();
>>>> }
>>>> }
>>>>
>>>>
>>>> here's the makefile used to compile the jnitest.dll:
>>>> ------------------------------------------------
>>>> gcc_opt = -O3 -std=c99 -DCYGWIN -Wl,--kill-at \
>>>> -fno-omit-frame-pointer -I${JAVA_HOME}/include/win32 \
>>>> -I${JAVA_HOME}/include -Wall -D_JNI_IMPLEMENTATION_
>>>> gcc = gcc
>>>> gfc = gfortran
>>>> gfc_opt = -O3 -fno-underscoring -fno-f2c -W -Wunused \
>>>> -Wuninitialized -fno-omit-frame-pointer
>>>> ld_opt = -luuid -lole32 -fno-omit-frame-pointer -shared
>>>> ifeq ($(PROCESSOR_ARCHITEW6432), AMD64) #use mingw 64bit cross compilers
>>>> gcc_opt += -m64
>>>> gcc = x86_64-w64-mingw32-gcc
>>>> gfc = x86_64-w64-mingw32-gfortran
>>>> gfc_opt += -m64
>>>> ld_opt += -m64
>>>> endif
>>>>
>>>> ########################################################################
>>>>
>>>> allnof: jnitest_h jnitestnof;
>>>>
>>>> jnitest_h: JNItest.class; javah -classpath ./ JNItest
>>>>
>>>> jnitestnof: JNItest.c JNItest.h; \
>>>> ${gcc} ${gcc_opt} JNItest.c ${ld_opt} -o jnitest.dll
>>>>
>>>> ########################################################################
>>>>
>>>> # attempt to call fortran from JNI code; must link with gfortran else
>>>> # we're mssing fortran runtime libs, eg. _gfortran_st_write
>>>>
>>>> allf: f77o jnitest_h jnitestf;
>>>>
>>>> f77o: f77sub.o; ${gfc} ${gfc_opt} -c f77sub.f -o f77sub.o
>>>>
>>>> jnitestf: JNItest.c JNItest.h; \
>>>> ${gcc} -DF77SUB ${gcc_opt} -c JNItest.c -o JNItest.o; \
>>>> ${gfc} ${ld_opt} JNItest.o f77sub.o -o jnitest.dll
>>>>
>>>>
>>>>
>>>> --------------------------------------------------------------------------
>>>> the dll built w/o calling fortran (-DF77SUB not set; make jnitestnof)
>>>> prints (as it should):
>>>> "not calling fortran at all"
>>>>
>>>> ---------------------------------------------------------------------------
>>>> the dll built with calling fortran (-DF77SUB set; make jnitestf,
>>>> gfortran as linker) is expected to print:
>>>> calling fortran
>>>> here is fortran
>>>> back from fortran
>>>>
>>>> however, it produces an unsatisfied link error such as:
>>>>
>>>> java.lang.UnsatisfiedLinkError: D:\native\jnitest.dll: %1 is not a valid
>>>> Win32 application
>>>> at java.lang.ClassLoader$NativeLibrary.load(Native Method)
>>>> at java.lang.ClassLoader.loadLibrary0(ClassLoader.java:1803)
>>>> at java.lang.ClassLoader.loadLibrary(ClassLoader.java:1728)
>>>> at java.lang.Runtime.loadLibrary0(Runtime.java:823)
>>>> at java.lang.System.loadLibrary(System.java:1028)
>>>> at JNItest.<clinit>(JNItest.java:4)
>>>>
>>>> Note that the path to the gfortran runtime is included in the Windows
>>>> PATH variable:
>>>> PATH=D:\native;C:\CygWin\usr\i686-w64-mingw32\sys-root\mingw\bin;...
>>>>
>>>>
>>>> Thx.,
>>>> H.
>>>
>>> Hmm, for me the error message indicates that you either try to load
>>> jnitest.dll under foreign bitness of JVM. Are you using here 32-bit
>>> JVM and 64-bit DLL, or 64-bit JVM and 32-bit DLL?
>>> As this would describe what the error-message of java is showing.
>>>
>>> Regards,
>>> Kai
>>
>>
>> Kai,
>>
>> it's all 64bit!
>> Unless linking with x86_64-w64-mingw32-gfortran produces something
>> 32bit'ish.
>>
>> java -version
>> java version "1.6.0_24"
>> Java(TM) SE Runtime Environment (build 1.6.0_24-b07)
>> Java HotSpot(TM) 64-Bit Server VM (build 19.1-b02, mixed mode)
>>
>> x86_64-w64-mingw32-gfortran --version
>> GNU Fortran (GCC) 4.5.2
>>
>> x86_64-w64-mingw32-gcc --version
>> x86_64-w64-mingw32-gcc (GCC) 4.5.2
>>
>>
>> Is there any means to inspect the dll wrt its "bitness"?
>>
>> Greets,
>> H.
>
> Yes, you can use the objdump tool with option -f for this.
>
> Btw are the functions in your DLL exported? You can check this via
> x86_64-w64-mingw32-objdump tool, too. Use here -x option and see the
> dump about export table.
>
> Regards,
> Kai
Kai,
I've attached the outputs of 'x86_64-w64-mingw32-objdump -x' for the
dlls built with and without fortran.
Unfortunately, as I'm a mere mortal, I cannot comprehend what these
outputs tell me.
Thx.,
Hans
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