Thank you for the reply. I have one very weird problem (not sure if its a
bug).
I ran Chromium with arguments you told me and args.gn setup and when I run
this code
var obj143 = {};
obj143["test"] = {test: 1, test2: 2, test3: 3};
var obj221 = {};
obj221["test"] = {test3: 14, test5: 23, test6: 322222};
var obj343 = {};
obj343["test"] = "test13"
For some weird reason the third "test" never gets printed and it never
enters StoreIC::Store() function nor Object::SetProperty. What is the
reason for this? I print all keys that ever come in but third one never
enters for some reason. I also hooked into SetProperty hoping it will go in
there but it never does. Is there any other function I can hook where I can
have a guarantee all property sets will go through?
On Friday, November 11, 2022 at 2:49:09 PM UTC+1 Jakob Kummerow wrote:
> On Fri, Nov 11, 2022 at 1:15 PM Filip Petronijevic <fpetronij...@raf.rs>
> wrote:
>
>> I treced down 'job' macro from tools/gdbinit and I found out it calls in
>> the end
>> https://source.chromium.org/chromium/chromium/src/+/main:v8/src/objects/objects.h;drc=a0dedabb214a245c792009e64baf333c7e8d7357;l=679
>>
>> which is shortPrint. This still doesn't show me all level depths of an
>> object but rather first levels of representation and their
>> corresponding addresses.
>>
>
> Yes.
>
>
>> Do I have to manually go in these recursive depths or is there any better
>> way like to Stringify it? I'm trying to Stringify this *value *object
>> located in
>> https://source.chromium.org/chromium/chromium/src/+/main:v8/src/ic/ic.cc;l=1847;bpv=1;bpt=0?q=ic.cc&ss=chromium%2Fchromium%2Fsrc:v8%2F
>> but I have hard times converting it to a String
>>
>
> I don't know of a JSON.stringify equivalent for use in GDB. As I said, I'd
> inspect objects manually, level by level. If you find that you're spending
> too much time doing that, you could build your own tooling, e.g. a function
> that has a similar entry point as _v8_internal_Print_Object and internally
> wraps JsonStringify() and printf()s the result to stdout.
>
>
>> On Fri, Nov 11, 2022 at 12:26 PM Jakob Kummerow <jkum...@chromium.org>
>> wrote:
>>
>>> Thanks! I found this StoreIC::Store() function just yesterday while
>>>> debugging in D8 and it works even without (--nouse-ic flag), even though I
>>>> have no clue what this flag does as I can't find it in docs. But this
>>>> tracks all of the keys and objects created.
>>>
>>>
>>> No, it won't catch all of them without the flag, but if it catches the
>>> ones you care about, that's good enough.
>>>
>>>
>>>> The main problem now is the following line of code in StoreIC::Store()
>>>> function (
>>>> https://source.chromium.org/chromium/chromium/src/+/main:v8/src/ic/ic.cc;l=1847;bpv=1;bpt=0?q=ic.cc&ss=chromium%2Fchromium%2Fsrc:v8%2F
>>>>
>>>> )
>>>>
>>>> When I cast this object (value) into JSObject and do shortPrint or
>>>> PrintProperties() it doesn't take in account all properties if for example
>>>> its recursive object like this test: {test1: { test2: "testhelloworld" } }
>>>> but rather it prints just test and gives memory lolcation to test1. I can
>>>> obviously recursively do this, but is there any prittier way of doing this
>>>> like via some JSON stringify function?
>>>>
>>>
>>> I'd just inspect objects manually, using the `job` macro from
>>> tools/gdbinit.
>>>
>>>
>>>> I found such JSON stringify function here
>>>> https://source.chromium.org/chromium/chromium/src/+/main:v8/src/json/json-stringifier.h;bpv=1;bpt=0
>>>>
>>>> but I have very hard trouble in passing arguments to this function and
>>>> printing String out of it as it return MaybeHandle object. Any help here
>>>> would be appreciated.
>>>>
>>>
>>> Appending `.ToHandleChecked()` may be of use here (if the
>>> stringification doesn't throw), but yeah, invoking such functions in GDB
>>> tends to not work.
>>>
>>>
>>>> On Friday, November 11, 2022 at 11:47:33 AM UTC+1 Jakob Kummerow wrote:
>>>>
>>>>> Maps don't keep lists of the objects that use them. To find all
>>>>> objects that use a given map, you'd have to walk the entire heap to find
>>>>> all objects, and filter them by map.
>>>>>
>>>>> Considering your previous question, I'm not sure finding all objects
>>>>> that use a given map will actually be helpful. A possible way to
>>>>> intercept
>>>>> creation of properties with a given name (e.g. "mainkey") would be to run
>>>>> with `--nouse-ic` and put a breakpoint on StoreIC::Store(). This is
>>>>> (obviously?) not an officially supported feature, and I haven't tried it,
>>>>> so you may encounter obstacles or limitations of the approach, but it
>>>>> might
>>>>> at least get you a little further.
>>>>>
>>>>> I guess you'd need this in Chrome, not just d8, so the full workflow
>>>>> is:
>>>>> - build a Debug build of Chrome. Be sure to set v8_optimized_debug =
>>>>> false in args.gn beforehand.
>>>>> - run with each renderer in a debugger: out/debug/chrome --no-sandbox
>>>>> --disable-hang-monitor --disable-extensions --js-flags="--nouse-ic"
>>>>> --renderer-cmd-prefix="xterm -e gdb -args"
>>>>> - bring a large amount of patience to both of these steps, and have
>>>>> enough RAM in your machine (64GB is good, dunno if 32GB is enough)
>>>>>
>>>>> Good luck!
>>>>>
>>>>>
>>>>> On Wed, Nov 9, 2022 at 3:19 PM Filip Petronijevic <fpetronij...@raf.rs>
>>>>> wrote:
>>>>>
>>>>>> Ok, I'll explain what problem I have and if there is any way of
>>>>>> solving it.
>>>>>>
>>>>>> Imagine I have following Javascript code:
>>>>>>
>>>>>> var obj1= {}
>>>>>> obj1["mainkey"] = {canvasComputed: "oewrewqioewrerqewjoijiqerw",
>>>>>> todata: "somerandomdata"}
>>>>>>
>>>>>> var obj2= {}
>>>>>> obj2["mainkey"] = "some big string"
>>>>>>
>>>>>> var obj3 = {}
>>>>>> obj3['mainkey'] = {test: {test1:"somestring"}, test2: 3432}
>>>>>>
>>>>>>
>>>>>> I have 3 objects, they all share same Map. My question is if I know
>>>>>> what memory space this Map has, If I can use that to recursively find
>>>>>> all
>>>>>> property values of all objects that share that same Map? In this case to
>>>>>> list obj1's property values (canvasComputed, toData), obj2 property
>>>>>> values
>>>>>> (1 string) and obj3 property values(test object along with string
>>>>>> test2)
>>>>>> ?
>>>>>>
>>>>>> Or the only way I can list own properties of these objects is if I
>>>>>> know exact memory location of each of them? Is there any way I could
>>>>>> traverse from their Map or something they share in common (only mainkey
>>>>>> key) and use this fact to find all property values that hold mainkey as
>>>>>> a
>>>>>> key?
>>>>>>
>>>>>>
>>>>>> When I do %DebugPrint(obj1) I can see its property values and that
>>>>>> this object shares same map as other objects, but I'm trying to find a
>>>>>> way
>>>>>> to generalize this by starting from some common memory slot they all
>>>>>> share
>>>>>> and traverse up recursively or whatever to get all property values?
>>>>>>
>>>>>> Best regards
>>>>>>
>>>>>> --
>>>>
>>>
--
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