Varargs bindings do not work in java 19 on the macbook pro M1 MAX

[Maurizio Cimadamore]

Do you get the error even if you add the asVariadic call, as noted by Jorn?

Maurizio

On 24/10/2022 15:38, Mark Hammons wrote:
> Sorry, yes there's an error there. However, this was not the first 
> place I noticed the error. Rather, I noticed that my binding to 
> sprintf was returning halfway malformed strings like   `1810529328 
> hello: �_�����{���\���^��@xA�!$@�!@����@Q@ 922798592` when the 
> following test code was run:
> ```
> valformat= Ptr.copy("%i hello: %s %i")
> valbuffer= Ptr.blankArray[Byte](256)
> assertEquals(format.copyIntoString(200), "%i hello: %s %i")
> Cstd.sprintf(buffer, format, 1, Ptr.copy("hello"), 2)
> assertEquals(buffer.copyIntoString(256), "1 hello: hello 2")
> ```
>
> With the fixed code above, I get the following result from add_var:
>
> -1884714972
>
> ~Mark
>
> On Mon, Oct 24, 2022 at 3:23 PM Maurizio Cimadamore 
> <maurizio.cimadamore at oracle.com> wrote:
>
>     Hi Mark,
>     interesting. On M1 we have currently few issues - see also this:
>
>     https://bugs.openjdk.org/browse/JDK-8275584
>
>     Stack spilling doesn't always occur correctly, however I note that
>     your example should not spill on the stack, so it should be immune.
>
>     Is your C code correct? I see you do _two_ va_arg per loop
>     iteration, which surely would leave you accessing invalid data.
>     E.g. in this case n = 2, so the loop would do two iterations, and
>     va_arg will be called _four_ times? Am I missing something?
>
>     I'd rewrite it as:
>
>     ```
>         for(int i = 0; i < n; i++) {
>             int i = va_arg(ptr, int);
>             printf("lala %d", i);
>             Sum += i;
>         }
>     ```
>
>     And test again.
>
>     Maurizio
>
>     On 24/10/2022 13:40, Mark Hammons wrote:
>>     Hi all,
>>
>>     I was testing panama on java 19 with my work issued macbook pro,
>>     and my varargs method bindings were returning invalid data.
>>
>>     I thought that maybe it was a failure in my own code, but I
>>     couldn't work around it so I created a test instance using
>>     manually written code:
>>
>>     test("manual varargs") {
>>     vallinker= Linker.nativeLinker().nn
>>     valsl= SymbolLookup.loaderLookup().nn
>>     valmh= linker
>>     .downcallHandle(
>>     sl.lookup("add_var").nn.orElseThrow(),
>>     FunctionDescriptor.of(JAVA_INT, JAVA_INT, JAVA_INT, JAVA_INT)
>>     )
>>     .nn;
>>     valres= MethodHandleFacade.callVariadic(mh, 2, 1,
>>     2).asInstanceOf[Int]
>>     assertEquals(res, 3)
>>     }
>>     #include<stdarg.h>
>>     #include<stdio.h>
>>     intadd_var(intn, ...) {
>>     intSum = 0;
>>     va_list ptr;
>>     va_start(ptr, n);
>>     for(inti = 0; i < n; i++) {
>>     inti = va_arg(ptr, int);
>>     printf("lala %d", i);
>>     Sum += va_arg(ptr, int);
>>     }
>>     va_end(ptr);
>>     returnSum;
>>     } The output of the test code is consistent with my autogenerated
>>     code,
>>     the Ints are not reaching the add_var function in a proper state,
>>     and therefore
>>     add_var is returning something like 840370212 instead of 3.
>
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