Can't find the bug

[Bernd Müller]

Dear Gavin,

thank you very much for extracting the code.
Eventually, it would be much easier to do a "mvn test". To do so
please clone:
https://github.com/BerndMuller/ffm2

Error still:
StdLibTest.foo:49->strcat:60 » IndexOutOfBounds Out of bound access on segment MemorySegment{ array: 
Optional.empty address:139631472807584 limit: 0 }; new offset = 0; new length = 1

looks for me like strcat changes the array size

Kind Regards,

Bernd

Am 04.01.23 um 02:12 schrieb Gavin Ray:
> Maurizio, the code I was able to get out of the email is below:
> 
> public class StdLibTest {
> 
> private static MethodHandle strlen; // C's strlen() function
> private static MethodHandle strcat; // C's strcat() function
> 
>      @BeforeAll
> public static void locateFunctions() {
> Linker linker = Linker.nativeLinker();
> strlen = linker.downcallHandle(linker.defaultLookup().find("strlen").get(),
> FunctionDescriptor.of(JAVA_LONG, ADDRESS));
> strcat = linker.downcallHandle(linker.defaultLookup().find("strcat").get(),
> FunctionDescriptor.of(ADDRESS, ADDRESS, ADDRESS));
>      }
> 
> 
>      @Test
> public void strlen() throws Throwable {
> try (Arena arena = Arena.openConfined()) {
> MemorySegment segment = arena.allocateUtf8String("Hello");
> int length = (int) (long) strlen.invoke(segment);
> Assertions.assertSame(5, length);
>          }
>      }
> 
>      @Test
> public void foo() throws Throwable {
> String result = strcat("hello", "world");
>      }
>      /**
>       * This is a one to one copy of strcat test taken from  StdLibTest.java test from OpenJDK
>       */
> String strcat(String s1, String s2) throws Throwable {
> try (var arena = Arena.openConfined()) {
> MemorySegment buf = arena.allocate(s1.length() + s2.length() + 1);
> buf.setUtf8String(0, s1);
> MemorySegment other = arena.allocateUtf8String(s2);
> return ((MemorySegment)strcat.invokeExact(buf, other)).getUtf8String(0);
>          }
>      }
> }
> 
> On Tue, Jan 3, 2023 at 12:55 PM Maurizio Cimadamore <maurizio.cimadamore at oracle.com 
> <mailto:maurizio.cimadamore at oracle.com>> wrote:
> 
>     Hi Bernd,
>     this mailing list truncates attachments. If you want us to look at some
>     code you will have to paste it somewhere :-)
> 
>     Cheers
>     Maurizio
> 
>     On 03/01/2023 17:14, Bernd Müller wrote:
>      > Dear all,
>      >
>      > I try to train FFM. I even master quick sort but became desperate on
>      > strcon.
>      >
>      > Attached you will find a Maven project with the strcon test copied one
>      > to one from
>      > OpenJDK 20 sources.
>      >
>      > "mvn test" results in
>      >
>      > [ERROR] Errors:
>      > [ERROR]   StdLibTest.foo:49->strcat:60 » IndexOutOfBounds Out of bound
>      > access on segment MemorySegment{ array: Optional.empty
>      > address:139636573277136 limit: 0 }; new offset = 0; new length = 1
>      >
>      > I am running OpenJDK 64-Bit Server VM (build 20-ea+29-2280, mixed
>      > mode, sharing) on Fedora 36.
>      >
>      > Please, can someone help ?
>      >
>      > Kind Regards,
>      >
>      > Bernd
>      >
> 


-- 
Prof. Dr. Bernd Müller

Ostfalia
Hochschule für angewandte Wissenschaften
- Hochschule Braunschweig/Wolfenbüttel -
Fakultät Informatik
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