Usage of C++ features (original) (raw)

Lindenmaier, Goetz goetz.lindenmaier at sap.com
Fri Feb 7 04:01:15 PST 2014

Hi,

Thanks a lot for all the feedback! To summarize, there is nothing in the pipe besides the exceptions in the compiler, but the desire to use new features/stl once compiler issues are resolved.

I have this lingering feeling that we shouldn't need to use template template parameters for the binaryTreeDictionary code but I haven't experimented with Yes Mikael, you are right. You don't need them. I would appreciate a lot if the following webrev would be considered as contribution to jdk9 and jdk8u20. http://cr.openjdk.java.net/~goetz/webrevs/rm_tmptmp_param/

If I don't get any objections I'll open a bug and mail a proper RFR?

I compiled it on linuxx86_64 with gcc 4.3.4 and 4.8, and on sparcv9 with SS12u1. I tested dbg, fdbg and opt builds. I did some simple tests. Tonight the change will run with all our tests on the ppc port, build on windows and sparc included.

Best regards, Goetz.

-----Original Message----- From: Mikael Gerdin [mailto:mikael.gerdin at oracle.com] Sent: Donnerstag, 6. Februar 2014 12:56 To: hotspot-dev at openjdk.java.net Cc: David Holmes; Lindenmaier, Goetz Subject: Re: Usage of C++ features

On Thursday 06 February 2014 21.27.51 David Holmes wrote:

Hi Goetz,

On 6/02/2014 8:33 PM, Lindenmaier, Goetz wrote: > Hi, > > wrt. our (SAPs) various ports which are running on old machines, built > with old compilers for compatibility, I would like to find out about > the OpenJDK policy regarding 'real' C++ features. I don't think there is such a thing as "OpenJDK policy" for this. Things need to be evaluated on their merits taking into account a range of factors, including compiler compatibility issues. > Recently, we found increasing usage of C++ features. > > - 'throw()' in nmethod operator new > - usage of namespace std:: AFAICS only std::nothrow is in use, which combines with the use of throw() in numerous (most?) operator new definitions to make it clear that these don't throw any exceptions. That said the compiler folk have expressed interest in using C++ exceptions within the compiler. > - template template parameters in binaryTreeDictionary.hpp|cpp Can't comment on that.

I have this lingering feeling that we shouldn't need to use template template parameters for the binaryTreeDictionary code but I haven't experimented with it. I'd prefer to simplify that just for the sake of sanity.

/Mikael

> We would like to know whether you are planning to increase the > usage of C++ or even use C++11 features. Or, whether you are planning > to keep the policy to avoid C++ features that caused problems to > compilers in the past. I can envisage usage of C++11 atomics at some point. But it depends on it being supported across sufficient compilers. What else is coming in C++11? I think everything has to be considered on a case-by-case basis. You presumably have some things in mind ? Just my 2c. I'm not a policy maker. :) Cheers, David > Best regards, > > Goetz.

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