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JavaScript:New to SpiderMonkey: Difference between revisions
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Wrote a tutorial for your first patch.
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This is a page to help new member of the JS team or new contributors to SpiderMonkey to orient themselves. It's maintained by Paul Biggar (pbiggar@mozilla.com), who is currently new to SpiderMonkey. Please help by telling me what you found useful when you were new. | This is a page to help new member of the JS team or new contributors to SpiderMonkey to orient themselves. It's maintained by Paul Biggar (pbiggar@mozilla.com), who is currently new to SpiderMonkey. Please help by telling me what you found useful when you were new. | ||
== Quick getting started tutorial == | == Quick getting started tutorial == | ||
We'll assume you're on a Unix-y platform, and that you know what you're doing. We'll ignore nearly all details. | |||
- | |||
Get the code from the repository. | |||
- | |||
hg clone http://hg.mozilla.org/tracemonkey | |||
- | |||
- | The tracemonkey directory is a full copy of all the firefox source code. So we'll need to build it. | ||
- Submit patch | |||
cd tracemonkey | |||
make -f client.mk build # this takes about an hour if you throw 4 cores at it, so this might be a good time to fill in the assignment paperwork (TODO link). | |||
This builds an "out-of-source" build, where the object files and binaries are in obj-i686-pc-linux-gnu. | |||
Do we need a .mozconfig file? | |||
Most of the time, you'll be working with the Javascript shell, instead of the full Firefox browser. So let's build the shell: | |||
cd js/src | |||
mkdir build_DBG.OBJ | |||
cd build_DBG.OBJ | |||
../configure --enable-debug --disable-optimize | |||
At this point, you're ready to make your first fix. | |||
TODO: something useless. Maybe adding a datemicrosecond function. | |||
Having made the change, build the shell again. | |||
cd build_DBG.OBJ | |||
make | |||
It builds. Hurray. Time to run the tests to check you haven't broken anything. | |||
python trace-tests/trace-test.py build_DBG.OBJ/js | |||
The trace tests are pretty quick, and should give you an idea if you've gotten something wrong. Assuming nothing goes wrong, try the ref-tests: | |||
cd build_DBG.OBJ | |||
python ../tests/jstests.py ./js --args="-j" | |||
Tests all pass. Congrats, you didn't break anything. Now, did you make it faster or slower? We benchmark using the v8 and SunSpider benchmarks. Get the benchmarks: | |||
svn checkout http://svn.webkit.org/repository/webkit/trunk/SunSpider | |||
And now run them: | |||
cd SunSpider | |||
./sunspider --args="-j" --shell=../build_DBG.OBJ/js --run=30 --suite=sunspider-0.9.1 | |||
cd .. | |||
So there's a few problems here. First, we tested a debug version. Secondly, we need to compare it against the old version if we're going to see if it got faster. OK, first, let's make an optimized build: | |||
mkdir build_OPT.OBJ | |||
cd build_OPT.OBJ | |||
../configure --disable-debug --enable-optimize | |||
make | |||
cd .. | |||
Repeat the sunspider steps above, and take note of the line that looks like: | |||
Results are located at sunspider-0.9.1-results/sunspider-results-2010-08-07-17.56.48.js | |||
You'll need that later. | |||
So we now need to go back and time the baseline version. This calls for a brief introduction to mercurial queues, which most people think is a pretty good way of managing their SpiderMonkey workflow: | |||
hg qinit | |||
hg qnew my_first_patch -f | |||
hg qrefresh | |||
This puts your current work into a patch, managed by Mercurial, symbolically called my_first_patch. To pop the patch off: | |||
hg qpop | |||
And we're back to our pristine version. So build again and rerun SunSpider again. You should now have two files like: | |||
sunspider-0.9.1-results/sunspider-results-2010-08-07-17.56.48.js | |||
Compare them using the compare script: | |||
cd SunSpider | |||
sunspider-compare-results FILE1 FILE2 | |||
==== Get a real bug ==== | |||
At this point, you've seen nearly everything you need to do hack on SpiderMonkey. So it's time to get a real bug to work on. Go to the IRC channel, #jsapi on irc.mozilla.org, and say the magic words: | |||
"I'm a beginner who wants to hack on SpiderMonkey. Can anyone give me a starter bug?" | |||
I'm hoping that works, I haven't tried it myself. | |||
Fix the bug, updating the bug report with your progress. When it's done, repeat all the steps above. Then it's time to get your patch into the tree. | |||
==== Submit a patch ==== | |||
To get the patch from mercurial, use: | |||
hg qdiff # if you're using queues or | |||
hg diff # if you're not | |||
Add it to the bug as an attachment. | |||
==== Get a review ==== | |||
Nothing gets into the tree without a review, so you'll need one. The easiest way to get a review is to go to the #jsapi IRC channel on irc.mozilla.org and ask for a volunteer. Point them to the bug. In all likelyhood, they'll give you a review and ask you to change something. Fix what they ask, resubmit the patch to bugzilla, and ask for another review. After you repeat this step a few times, they'll say something like "review=me" meaning it's now good to commit. | |||
==== Try server ==== | |||
On your first commit, you're likely to be a little wary of breaking things. Mozilla has a "tryserver" where you can send a patch, and it'll be built on tons of machines which will report back to you. | |||
The guide for getting "level 1" access, which you need for the try server, is here. Ask your reviewer to vouch for you, and send in the paperwork ASAP. | |||
Of course, your patch maybe small enough not to need the try server, so you don't always have to | |||
https://wiki.mozilla.org/Build:TryServer | |||
==== Commit ==== | |||
You can't commit until you have "level 2" access, and you don't have level 2 access (at time of writing, I don't have level 2 access), so you'll need someone to do this for you. The volunteer from IRC may do this, otherwise you'll need a new volunteer. | |||
After committing, a large series of tests will be run to make sure you didn't break anything. You'll need to hang around to make sure you didn't break something. Check http://tests.themasta.com/tinderboxpushlog/?tree=TraceMonkey for red marks. | |||
TODO: we don't want them worrying about false positives either, since there are plenty. | |||
== Everything you should know == | == Everything you should know == | ||