JDK-6890703: dtrace.o causes linker warnings

[Volker Simonis]

Hi,

we always get linker warnings like:

Linking vm...
ld: warning: symbol `Universe::_narrow_oop' has differing types:
        (file universe.o type=OBJT; file dtrace.o type=FUNC);
ld: warning: symbol `Universe::_methodKlassObj' has differing types:
        (file universe.o type=OBJT; file dtrace.o type=FUNC);

when compiling the HotSpot on Solaris.

I just found that there already exists a bug for this issue:
"JDK-6890703: dtrace.o causes linker warnings"
(https://bugs.openjdk.java.net/browse/JDK-6890703) but unfortunately
no solution.

I also found out, that this problem is related to newer dtrace versions.

Taking the following 'extern.d' dtrace program:

extern UseCompressedOops;

dtrace:helper:
{
  this->done = ``UseCompressedOops;
}

and compiling it with '/usr/sbin/dtrace -64 -D_LP64 -C -I. -G
-xlazyload -o /tmp/dtrace.o -s extern.d' results in following object
files:

For dtrace: Sun D 1.4.1

[Index] Value Size Type Bind Other Shndx Name

[2] | 0| 2009|OBJT |GLOB |0 |2 |___SUNW_dof
[1] | 0| 0|FUNC |GLOB |0 |UNDEF |UseCompressedOops

but for dtrace: Sun D 1.1

[Index] Value Size Type Bind Other Shndx Name

[2] | 0| 2007|OBJT |GLOB |0 |2 |___SUNW_dof
[1] | 0| 0|NOTY |GLOB |0 |UNDEF |UseCompressedOops

So the newer dtrace makes the external reference to '
UseCompressedOops' of type 'FUNC' which conflicts with HotSpot's
definition of UseCompressedOops' and results in a warning. On the
other hand, the old version of dtrace makes the external reference to
be of type 'NOTY' which doesn't seem to bother the linker.

I have no idea if this behaviour can be influenced (e.g. by giving the
externel reference the right type in D).

Is there any DTrace wizard out there who knows how this can be fixed?

Thank you and best regards,
Volker