Request for review 7170638: Use DTRACE_PROBE[N] in JNI Set and SetStatic Field.

[Mark Wielaard]

On Mon, 2012-10-01 at 15:50 -0400, Coleen Phillimore wrote:
> http://cr.openjdk.java.net/~coleenp/7170638/src/share/vm/prims/jni.cpp.udiff.html
> 
> In jni.cpp it looks like the macro change was a cleanup (?) but what 
> happened to this?  It seems to have gone away with the macro change?
> 
> *!    HS_DTRACE_PROBE_CDECL_N(hotspot_jni, SetStatic##Result##Field__entry,\*
> *       ( JNIEnv*, jclass, jfieldID FP_SELECT_##Result(COMMA Argument,/*empty*/) ) ); \
> *
> 
> On Solaris the  DECL_N things add the extern "C" declaration.
> 
> // Solaris dtrace needs actual extern function decls.
> #define HS_DTRACE_PROBE_DECL_N(provider,name,args) \
>    DTRACE_ONLY(extern "C" void HS_DTRACE_PROBE_FN(provider,name) args)
> 
> I tested solaris and it worked but I don't know how the extern "C" 
> declaration got declared.

See also the explanation that was submitted with the original patch:
http://mail.openjdk.java.net/pipermail/hotspot-dev/2012-May/005739.html

But yes, that is basically precisely what the cleanup does. Instead of
having to specify things twice using two different macros
HS_DTRACE_PROBE_CDECL_N and then HS_DTRACE_PROBE_N. Just use what the
rest of the jni.cpp file uses, the DTRACE_PROBEN macro which does both
of them if needed.

Cheers,

Mark