On Tuesday, February 10, 2015 at 6:59:20 PM UTC+2, Steve Fink wrote: > On 02/10/2015 01:06 AM, Erdal Mutlu wrote: > > Hi, > > > > I have been instrumenting the JS engine interpreter for logging memory > > updates on JS scripts. My current instrumentation logs every use of the > > interpreter for script execution which also includes browser (internal) > > script execution. I wanted to ask if there is a way to separate these > > internal calls from the user (webpage) specific scripts running on the > > interpreter. > > > > I couldn't be sure if this question should be directed to platform or > > js-engine so I am posting it to both. Thanks in advance. > > There's actually another list called js-engine. You're posting to > js-engine-internals, which is fine (and better than dev-platform). > > I do not completely understand your question. You say you are logging > "memory updates on JS scripts", but then you discuss logging script > executions. I'm not sure if you just want to log script invocations, > categorized by content vs internal, or if you are just doing that in > order to categorize memory accesses. > > All scripts live within a compartment, and you can tell from that > compartment whether the script is from content (user/webpage) or chrome > (browser/internal). Not only that, but all memory allocations that are > managed by the JS engine's garbage collector (we call them GC things) > are also contained with a compartment. There is other memory which may > be either controlled by a GC thing (as in, it will be automatically > freed when that GC thing is no longer live), or is completely external > to the GC. Those are harder to associate with content vs chrome. This is > what about:memory does -- it scans through all (well, most) of allocated > memory and categorizes it when possible, or else puts it an "Other" > category when it is not directly associated with a web page or chrome. > > Logging script execution crossings between content and chrome is another > matter, since it is about control flow. It's relatively easy to do if > you're only running in the interpreter, since you have to "enter" a > compartment in order to create or manipulate anything. You can > instrument those compartment entries. But I think the JITs do some > compartment-crossing internally, and that's harder to track. (You can > always run with the JITs disabled if that will work for whatever it is > you are trying to accomplish.) > > If you tell me more about what exactly you are trying to achieve, we > could probably be more helpful.
Thanks for the quick response and insight about the compartments. I've been working on a scheme to record the memories accessed during the execution of JS script. So far I have been adding some logging mechanism on the Interpret function (namely JSOP_GETNAME, JSOP_GETPROP, JSOP_SETNAME, JSOP_SETPROP). Basically, I am recording the values read and written to JS variables and properties. But I only want to record these values for scripts from content rather than chrome. Cheers, Erdal _______________________________________________ dev-tech-js-engine-internals mailing list dev-tech-js-engine-internals@lists.mozilla.org https://lists.mozilla.org/listinfo/dev-tech-js-engine-internals
