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

Lindenmaier, Goetz goetz.lindenmaier at sap.com
Fri Feb 7 05:48:26 PST 2014

Hi Mikael,

I removed the get_chunk as it seems wrong and unused. It's a good point to mention it in the RFR.

Thanks, the ::exact was a mismatch! I fixed the webrev.

Thanks for your feedback, Goetz.

-----Original Message----- From: Mikael Gerdin [mailto:mikael.gerdin at oracle.com] Sent: Freitag, 7. Februar 2014 13:33 To: Lindenmaier, Goetz Cc: hotspot-dev at openjdk.java.net; David Holmes Subject: Re: Usage of C++ features

Hi Goetz,

On Friday 07 February 2014 12.01.15 Lindenmaier, Goetz wrote:

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

As I hinted in my mail, I'd welcome this change.

I had a quick look through the patches and I noticed that you removed a get_chunk from binaryTreeDictionary.cpp, you should remember to point that out when you send the RFR.

Also, you forgot a

FreeBlockDictionary::atLeast);

FreeBlockDictionary::exactly);

Do you have any further input on this? Are you running with exactly instead of atLeast here or is this just a mis- merge? We'd appreciate any feedback you have about the policy in this code.

/Mikael

I compiled it on linuxx8664 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.

More information about the hotspot-dev mailing list