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Java Forum / General / December 2005Eclipse java compiler
Hi everyone, I've read a few rumours on the web about ejc, a natively build version of the Eclipse compiler. Apparently, someone managed to compile the eclipse compiler using GCJ and it runs really fast: http://sources.redhat.com/ml/rhug-rhats/2003-07/msg00008.html Has anyone managed to repeat this? It appears that this compiler is distributed with some Linux versions. A new fast compiler would be great as Jikes is no longer being maintained and the world is drifting towards Java 1.5, unsupported by jikes. If the native Eclipse compiler indeed is super fast and compiling on various platforms is possible, I would like to make it publicly available on many platforms under the Eclipse open source licence. Anyway, has anyone managed to repeat this? So far, I have managed to pull out all the compiler source code and compile it into normal java bytecodes. As it is, this runs slightly slower than javac and significantly slower than jikes. As far as native compilation goes, the program compiles but crashes. I believe it has something to do with dynamic loading of resources (normally done from the CLASSPATH). I have no experience with GCJ or native Java compilation so I may be missing out a step (compiling the resources maybe?) the command i am using (on Windows) is gcj ejc.jar --main=org.eclipse.jdt.internal.compiler.batch.Main -o ejc.exe (where ecj.jar contains the required CLASS files + the resource files) If anyone has managed to compile and run the compiler successfully or is interested in helping out with this, any help would be appreciated. Cheers Tin >I've read a few rumours on the web about ejc, a natively build version >of the Eclipse compiler. Apparently, someone managed to compile the >eclipse compiler using GCJ and it runs really fast: Jet is also supposedly able to natively compile it. See http://mindprod.com/jgloss/jet.html  SignatureCanadian Mind Products, Roedy Green. http://mindprod.com Java custom programming, consulting and coaching. Yes, I have managed to compile it using JET but this resulted in no performance improvement. Maybe in this case there is no performance improvement with native compilation, or maybe JET doesn't do the job well. Has anyone actually used eclipse-ecj, which comes with some linux distros? Is it fast? Cheers Tin >Yes, I have managed to compile it using JET but this resulted in no >performance improvement. Maybe in this case there is no performance >improvement with native compilation, or maybe JET doesn't do the job >well. Surely it started up faster?? SignatureCanadian Mind Products, Roedy Green. http://mindprod.com Java custom programming, consulting and coaching. >Surely it started up faster?? I ran a few experiments and javac ran faster in all of them. I wouldn't call it a thorough investigation but it was fairly convincing. It is hard to measure how much of the time is startup and how much is compilation. Perhaps the bought version of JET performs better. I used the trial version. >I ran a few experiments and javac ran faster in all of them. I wouldn't >call it a thorough investigation but it was fairly convincing. It is >hard to measure how much of the time is startup and how much is >compilation. Perhaps the bought version of JET performs better. I used >the trial version. you mean java.exe. Jet used Javac.exe to prepare the class files. Did you have a lot of dynamic loading of classes not known to jet at compile time? SignatureCanadian Mind Products, Roedy Green. http://mindprod.com Java custom programming, consulting and coaching. no, i mean javac.exe. it compiles code faster than the eclipse compiler compiled with JET. as far as I know, there are no dynamically loaded classes, although some resources are loaded through the class loader. >no, i mean javac.exe. it compiles code faster than the eclipse compiler >compiled with JET. as far as I know, there are no dynamically loaded >classes, although some resources are loaded through the class loader. Compilation speed of an optimising compiler is generally not a metric of interest. You only do it as part of major builds and use the standard compiler for rapid compile/debug cycles (e.g. in Eclipse). What you care about his how fast the generated code runs. SignatureCanadian Mind Products, Roedy Green. http://mindprod.com Java custom programming, consulting and coaching. > >no, i mean javac.exe. it compiles code faster than the eclipse compiler > >compiled with JET. as far as I know, there are no dynamically loaded [quoted text clipped - 7 lines] > Canadian Mind Products, Roedy Green. > http://mindprod.com Java custom programming, consulting and coaching. Amen! I think you guys have misunderstood my question. I will try to be more clear. I am looking for a very fast compiler. Jikes used to do the job well but does not support 1.5. Javac and the eclipse compiler are good compilers but are too slow (I am dealing with a lot of source code needing to be compiled), so I am looking for a fast alternative. My idea was to compile the eclipse compiler natively in order to improve its speed. Apparently this is possible and has been done before. >I think you guys have misunderstood my question. I will try to be more >clear. I am looking for a very fast compiler. Jikes used to do the job >well but does not support 1.5. Are you using ANT? If not that, that should drastically speed up your javac compiles since it loads javac only once no matter how many modules you compile. Most of the time of a Javac compile is lost loading Javac. Once it gets loaded, it whips along quite fast. see http://mindprod.com/jgloss/ant.html SignatureCanadian Mind Products, Roedy Green. http://mindprod.com Java custom programming, consulting and coaching. >>I think you guys have misunderstood my question. I will try to be more >>clear. I am looking for a very fast compiler. Jikes used to do the job [quoted text clipped - 6 lines] > > see http://mindprod.com/jgloss/ant.html Cool This could help as well http://www.newegg.com/Product/Product.asp?Item=N82E16819103558 Keep your code in a RAMDISK, and try to keep as much ram as possible to prevent anything from using virtual memory. -- LTP :) On Wed, 14 Dec 2005 18:04:33 -0700, "Luc The Perverse" <sll_noSpamlicious_z_XXX_m@cc.usu.edu> wrote, quoted or indirectly quoted someone who said : >Keep your code in a RAMDISK, and try to keep as much ram as possible to >prevent anything from using virtual memory. Have you tried that? I would think it would be counterproductive. The compiler could probably better use the extra ram for workspace -- symbol tables and the like. SignatureCanadian Mind Products, Roedy Green. http://mindprod.com Java custom programming, consulting and coaching. > On Wed, 14 Dec 2005 18:04:33 -0700, "Luc The Perverse" > <sll_noSpamlicious_z_XXX_m@cc.usu.edu> wrote, quoted or indirectly [quoted text clipped - 6 lines] > compiler could probably better use the extra ram for workspace -- > symbol tables and the like. I have never had enough ram to try that :) But I figure if you have 4 Gbs of RAM or maybe more under a 64 bit OS it could be feasable. In the spirit of my original post, if one is spending cerca 1000$ for a processor to increase compilation speed, spending the extra money for a few extra gigs of ram or some SCSI hard disks would likely make sense too. For me I'm usually working with a small piece of code, then I try to compile and it fails with errors. Then I correct an error and repeat. The amount of disk space for my needs would be very small - perhaps I will try it :) I use a windows XP OS - I wonder . . . I wonder if there is some way to tell Windows to favor caching of the files used in the compilation . . . -- LTP :) > I use a windows XP OS - I wonder . . . I wonder if there is some way > to tell Windows to favor caching of the files used in the compilation Try using Eclipse on Linux instead. Signaturehttp://www.munted.org.uk Anyone that thinks an imaginary deity is going to protect them against earthquakes and hurricanes needs psychiatric help. >> I use a windows XP OS - I wonder . . . I wonder if there is some way to >> tell Windows to favor caching of the files used in the compilation > > Try using Eclipse on Linux instead. . . . Ok - though this has not aided my wonderment ;) -- LTP :) > Has anyone actually used eclipse-ecj, which comes with some linux > distros? Is it fast? Yes and it was different enough (or broken) that I had a hard time making it do anything useful. I uninstalled it and downloaded Java 1.5 + Eclipse and everything works well now. BTW, my old computer ran Linux + Eclipse + Sun JDK 1.4 on a 1Ghz PIII with 1 Gig RAM. It was not slow...so I am not sure how much gain ECJ will get on a modern day machine. Honestly I find that JIT works really well once the app is loaded and running. Frankly, Eclipse compiles Java faster than a C compiler compiles C...it's all perspective I suppose. -Misk >>I've read a few rumours on the web about ejc, a natively build version >>of the Eclipse compiler. Apparently, someone managed to compile the >>eclipse compiler using GCJ and it runs really fast: > > Jet is also supposedly able to natively compile it. See > http://mindprod.com/jgloss/jet.html Would perhaps some benevolent individual who already has Jet be willing to share the natively compiled version? -- LTP :) Free MagazinesGet these publications absolutely FREE for up to 12 months. There are no hidden fees and no obligation. Simply choose a title, complete the application form and submit it. Read more ...
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