Re: JNI bug?

[Andrew Haley <aph at redhat dot com>]

Marco Trudel writes:
 > Hey all
 > 
 > Here's an interesting one where GCJ sometimes isn't doing the same as a 
 > Sun JDK (no no Andrew, don't stop reading ;-)). Check out this little 
 > Java class:
 > 
 > public class NativeBooleanTest
 > {
 > 	public static void main(String[] args)
 > 	{
 > 		System.loadLibrary("nativeBoolean");
 > 		nativePrintBoolean(false);
 > 		nativePrintBooleanAsInt(false);
 > 	}
 > 	
 > 	private static native void nativePrintBoolean(boolean b);
 > 	private static native void nativePrintBooleanAsInt(boolean b);
 > }
 > 
 > Now this c code:
 > 
 > #include <jni.h>
 > 
 > JNIEXPORT void JNICALL Java_NativeBooleanTest_nativePrintBoolean
 > 	(JNIEnv *env, jclass c, jboolean b)
 > {
 > 	printf("nativePrintBoolean: %d\n", b);
 > }
 > 
 > JNIEXPORT void JNICALL Java_NativeBooleanTest_nativePrintBooleanAsInt
 > 	(JNIEnv *env, jclass c, jint b)
 > {
 > 	printf("nativePrintBooleanAsInt: %d\n", b);
 > }
 > 
 > 
 > On a sun JVM, the output will be:
 > nativePrintBoolean: 0
 > nativePrintBooleanAsInt: 0
 > 
 > On GCJ, in this minimalistic sample, it will always be:
 > nativePrintBoolean: 0
 > nativePrintBooleanAsInt: 10084864
 > 
 > In a huge library I debugged for this, GCJ 4.3 gives twice 0 if 
 > optimization is disabled and also "10084864" as soon as optimization is 
 > enabled. GCJ 4.2 gives twice 0 in -O3 mode, GCJ 4.3 no longer.
 > 
 > 
 > So,what do others think? What is the problem? Should there be an 
 > implicit cast? Is the code wrong? If yes, should it be attended so that 
 > the Sun RE is met?
 > Unfortunately, this seems to go into the same unpleasant RE topic as my 
 > Arrays patch... But it also might be a GCJ bug. I don't know for sure.

zorro:~ $ ~/gcc/trunk/install/bin/gcj NativeBooleanTest.java --main=NativeBooleanTest -fjni -O2
zorro:~ $ ~/gcc/trunk/install/bin/gcc -fpic -shared -o libnativeBoolean.so  nativeBoolean.c  
zorro:~ $ LD_LIBRARY_PATH=.:~/gcc/trunk/install/lib64 ./a.out 
nativePrintBoolean: 0
nativePrintBooleanAsInt: 0
zorro:~ $ ~/gcc/trunk/install/bin/gcj NativeBooleanTest.java --main=NativeBooleanTest -fjni -O3
zorro:~ $ LD_LIBRARY_PATH=.:~/gcc/trunk/install/lib64 ./a.out 
nativePrintBoolean: 0
nativePrintBooleanAsInt: 0
zorro:~ $ ~/gcc/trunk/install/bin/gcc -fpic -shared -o libnativeBoolean.so  nativeBoolean.c  -O2
zorro:~ $ LD_LIBRARY_PATH=.:~/gcc/trunk/install/lib64 ./a.out 
nativePrintBoolean: 0
nativePrintBooleanAsInt: 0