Would you suggest to build v8 such that I can debug it as I want ? On Tue, 11 Sep 2018 at 12:44, dan Med <litokis.ta...@gmail.com> wrote:
> I've already read that guide and watched those videos, but i'm not > interested at a HIGH level definition, i wan't to see the hole picture > starting from the very buttom or at least at a low level.... > In those presentation they just give the very top of the iceberg which > isn't really helpful > > Il giorno mar 11 set 2018 alle ore 12:42 dan Med <litokis.ta...@gmail.com> > ha scritto: > >> Ok so to answer the memory side i believe i should build v8 and then >> debug it and see the memory..... >> But another question arises, how is data/pointers or anything else >> represented in memory ? There should be i guide i hope ... >> >> Il giorno mar 11 set 2018 alle ore 12:41 dan Med <litokis.ta...@gmail.com> >> ha scritto: >> >>> So the location of the length regarding my allocation is base on which >>> algorithm v8 uses to find the free space it needs? >>> >>> Anyway, i still don't get when arraybuffer::append will be called or can >>> be called .... >>> One more thing when i create a new instance let's say this example again: >>> Arraybuffer foo = new arraybuffer(10) >>> >>> so an arraybuffer of CAPACITY will be allocated so static const int >>> kDefaultBufferCapacity >>> <https://cs.chromium.org/chromium/src/third_party/blink/renderer/platform/wtf/typed_arrays/array_buffer_builder.cc?l=38&gs=kythe%253A%252F%252Fchromium%253Flang%253Dc%25252B%25252B%253Fpath%253Dsrc%252Fthird_party%252Fblink%252Frenderer%252Fplatform%252Fwtf%252Ftyped_arrays%252Farray_buffer_builder.cc%2523YXDT7WTpXCAcuhdyTlkuCzsfCzI%25252BoHLRFAlkbCrkx4g%25253D&gsn=kDefaultBufferCapacity&ct=xref_usages> >>> = 32768; >>> 32768 bytes will be allocated but only 10 of those will be marked as >>> BYTE_USED hence i will only be able to access those with >>> a proper typedarray. >>> >>> If i start reading the code on how v8 compiles i will have even more >>> questions, i think i need the low stuff, something like how does it create >>> the machine code that will be executed where will it be stored such and >>> such ... >>> >>> >>> Another developer replied to me that the basic structure of v8 is a loop >>> that reacts when certain events happen.. >>> >>> I'm really glad you're answering my questions ! >>> >>> >>> >>> >>> >>> >>> >>> Il giorno mar 11 set 2018 alle ore 12:32 @soylentgraham < >>> gra...@grahamreeves.com> ha scritto: >>> >>>> Let's not confuse matters by adding Node into the mix! :) >>>> >>>> > by doing buffer_->Data() i'm accessing a defined length space >>>> somewhere in memory but on the heap since there's the new operator >>>> involded.. >>>> >>>> It uses the new operator, but this can, and is, overloaded. (in v8). As >>>> I said above, it will use the memory allocator, which you can override with >>>> your own (the code I provided), so, it is most likely on a heap, but it may >>>> not. For your purposes, it is memory allocated SOMEWHERE, by SOMETHING. >>>> >>>> >>>> > and where data points to the length of that space is the same as the >>>> one declared for example as >>>> > Arraybuffer a = new arraybuffer(10) so data will point to a space in >>>> memory who's length is 10 bytes? >>>> >>>> As I keep saying, this MAY NOT be the case. It depends on many things. >>>> As you've seen from the code, an arraybuffer has a memory-allocation of >>>> size CAPACITY, and the number of bytes used is BYTES_USED (in this case, >>>> 10). The usage can grow and shrink, to save reallocation (which is >>>> traditionally an expensive thing) >>>> The most likely case, is that yes, it will probably point at some >>>> memory allocated by the allocator assigned to the isolate of 10 bytes. The >>>> only way you can verify that in your case is by debugging it, stepping into >>>> the code and seeing what it does. >>>> >>>> >>>> > So, what i'd like to understand is how v8 would compile a javascript >>>> "file" by that i mean how it would be >>>> > represented in memory which methods will be called and so on.... >>>> >>>> This is quite different from the use of array buffers! >>>> This question is more about compiling. How the memory is laid out after >>>> compilation... is going to be a very difficult thing to delve into even for >>>> the engine developers (they may know there's lists of functions, scripts, >>>> but how it's laid out EXACTLY probably isn't of concern to them) >>>> >>>> If you want to learn more about how the script compiles, how the >>>> virtual machine executes, delve into this page, and the videos at the >>>> bottom (while they're from 2008, the fundamentals probably haven't changed >>>> that much) >>>> >>>> http://thibaultlaurens.github.io/javascript/2013/04/29/how-the-v8-engine-works/ >>>> >>>> If you're interested in finding out how v8 compiles, and executes code, >>>> I would totally ignore the memory side of things and get a grasp on what >>>> it's doing at a high level, (ie. the theory) then low level (what gets >>>> stored, how things are found, and arranged) first. >>>> THEN you could browse the allocations and see WHERE everything is (I'm >>>> not sure what use this would be to anyone who is working with more than >>>> 50mb of ram though :) >>>> >>>> I would really encourage you to step through the code though! (find >>>> script::compile and just step through from there) >>>> This will make lots of things make sense! (because everything is named >>>> properly in the code :) >>>> >>>> >>>> On Tuesday, 11 September 2018 08:57:53 UTC+1, J Decker wrote: >>>>> >>>>> >>>>> >>>>> On Tue, Sep 11, 2018 at 12:44 AM dan Med <litoki...@gmail.com> wrote: >>>>> >>>>>> First of all, i'd like to say that for me the documentation is >>>>>> really..... useless from a real technical point of view. >>>>>> So, what i'd like to understand is how v8 would compile a javascript >>>>>> "file" by that i mean how it would be >>>>>> represented in memory which methods will be called and so on.... >>>>>> (In the classes defined in the various v8 files, you don't get that >>>>>> sort of feeling about the memory allocator and such... >>>>>> i'd like to understand how to gather that knowledge.) >>>>>> Now, u said "kind of" for my question which was, when i allocate an >>>>>> arraybuffer in javascript will v8 call arraybufferbuilder ? >>>>>> But then one of my questions was how to invoke the append method? >>>>>> I know that if someone want's to expand an arraybuffer it will have >>>>>> to create another one and copy there those values... >>>>>> This is how i have a rough vision of the arraybuffer in memory: >>>>>> >>>>>> buffer ------------> [ DATA ] >>>>>> "simple pointer" "size of the bytes which i can manipulate with a >>>>>> typedarray" >>>>>> >>>>> >>>>> There's really nothing special about the memory.... gets the size of a >>>>> file, allocates a buffer and reads the file into it. >>>>> https://github.com/d3x0r/sack.vfs/blob/master/src/vfs_module.cc#L479 >>>>> >>>>> size_t len = sack_vfs_size( file ); >>>>> uint8_t *buf = NewArray( uint8_t, len ); >>>>> sack_vfs_read( file, (char*)buf, len ); >>>>> Local<Object> arrayBuffer = ArrayBuffer::New( isolate, buf, len ); >>>>> >>>>> where buf is allocated from some allocator V8 doesn't even know >>>>> about.... the next few lines of code wrap it in a weak persistent holder >>>>> that tracks when the object gets deleted to be able to delete the 'buf' >>>>> allocated... >>>>> https://github.com/d3x0r/sack.vfs/blob/master/src/vfs_module.cc#L447 >>>>> (releaseBuffer) >>>>> >>>>> You can find information about ArrayBuffer by searching for 'nodejs >>>>> addon arraybuffer' Node is a handy platform for writing code that >>>>> extends >>>>> V8; 99% of the code you will write is actually interfacing to V8 and not >>>>> Node. >>>>> >>>>> >>>>>> Il giorno mar 11 set 2018 alle ore 00:07 @soylentgraham < >>>>>> gra...@grahamreeves.com> ha scritto: >>>>>> >>>>>>> > When I talk about typedarray or anything else I referr to the >>>>>>> JavaScript side, so create an arraybuffer it will invoke that class in >>>>>>> v8, >>>>>>> Kind of. >>>>>>> >>>>>>> > then build a view or not it depends how do I make v8 to call the >>>>>>> append method ? >>>>>>> I don't understand this question. >>>>>>> An array buffer in javascript is fixed in length. You cannot make it >>>>>>> grow or shrink on the javascript side. >>>>>>> To do anything, you need a view, so the code knows how to manipulate >>>>>>> the raw bytes in the array buffer. >>>>>>> See javascript documentation on array buffers; >>>>>>> https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/ArrayBuffer >>>>>>> >>>>>>> You personally shouldn't TRY to make it call the append method. If >>>>>>> it needs to grow, it'll grow. Why do you think you need to? Back to >>>>>>> previous messages, what are you trying to achieve?? >>>>>>> >>>>>>> Gather your thoughts, and try and answer some of the questions I've >>>>>>> asked in previous emails; I asked them to help guide you so people can >>>>>>> help >>>>>>> with your problem! (I'm still not exactly sure what you're trying to do) >>>>>>> >>>>>>> >>>>>>> On Monday, 10 September 2018 22:55:51 UTC+1, dan Med wrote: >>>>>>>> >>>>>>>> ATM I’m writing with my phone, here in EU is almost midnight so I >>>>>>>> will write u an email tomorrow fully detailed. >>>>>>>> >>>>>>>> Btw how do I call append ??? >>>>>>>> I’m interested in how v8 works and manages JavaScript code that’s >>>>>>>> all. >>>>>>>> >>>>>>>> When I talk about typedarray or anything else I referr to the >>>>>>>> JavaScript side, so create an arraybuffer it will invoke that class in >>>>>>>> v8, >>>>>>>> then build a view or not it depends how do I make v8 to call the append >>>>>>>> method ? >>>>>>>> >>>>>>>> On Mon, 10 Sep 2018 at 23:46, @soylentgraham < >>>>>>>> gra...@grahamreeves.com> wrote: >>>>>>>> >>>>>>>>> > First, how big is the data member of the object ? >>>>>>>>> >>>>>>>>> As I said before. Capacity is the size of the memory allocated >>>>>>>>> that data points at. >>>>>>>>> >>>>>>>>> >>>>>>>>> > Is it as big as the actual array buffer length which I declare >>>>>>>>> on JavaScript >>>>>>>>> >>>>>>>>> It will be either as big, or bigger. It can grow. >>>>>>>>> bytes_used will be the size that matches javascript. >>>>>>>>> >>>>>>>>> >>>>>>>>> > which I can build on top of it a typedarray ? >>>>>>>>> >>>>>>>>> This is a slightly different question, (and needs clarifying) >>>>>>>>> When you create a typedarray in C++, it needs an array buffer. >>>>>>>>> When you create a typedarray in javascript, it will have an array >>>>>>>>> buffer behind it. (which you may or may not have created in >>>>>>>>> javascript or >>>>>>>>> c++, there are several ways of approaching this) >>>>>>>>> >>>>>>>>> >>>>>>>>> > So, when a typedarray is build on top of an areaybuffer >>>>>>>>> instance, how do I get to call the arraybufferbuilder::append ? >>>>>>>>> >>>>>>>>> Aha! a more specific question! >>>>>>>>> Are you trying to call arraybufferbuilder::append in javascript, >>>>>>>>> or c++? >>>>>>>>> Why? are you trying to make a typedarray bigger? (in javascript or >>>>>>>>> c++?) >>>>>>>>> I believe once created they're a fixed size in javascript. >>>>>>>>> I have a feeling on the c++ side, you can't change the size once >>>>>>>>> created (but I may be wrong, you have direct access to the buffer's >>>>>>>>> buffercontents via the bufferview...) >>>>>>>>> >>>>>>>>> Can you make your question a lot more specific? post some code? >>>>>>>>> >>>>>>>>> >>>>>>>>> On Monday, 10 September 2018 22:38:16 UTC+1, dan Med wrote: >>>>>>>>>> >>>>>>>>>> First, how big is the data member of the object ? Is it as big as >>>>>>>>>> the actual array buffer length which I declare on JavaScript and >>>>>>>>>> which I >>>>>>>>>> can build on top of it a typedarray ? >>>>>>>>>> >>>>>>>>>> No, I’m just trying to understand how v8 works, I know it is a >>>>>>>>>> big thing but at least how it moves then I might read the code and >>>>>>>>>> understand, extra parts. >>>>>>>>>> >>>>>>>>>> So, when a typedarray is build on top of an areaybuffer instance, >>>>>>>>>> how do I get to call the arraybufferbuilder::append ? >>>>>>>>>> >>>>>>>>>> >>>>>>>>>> >>>>>>>>>> >>>>>>>>>> >>>>>>>>>> On Mon, 10 Sep 2018 at 23:30, @soylentgraham < >>>>>>>>>> gra...@grahamreeves.com> wrote: >>>>>>>>>> >>>>>>>>>>> I'm guessing you may be a bit new to unmanaged-memory >>>>>>>>>>> languages/systems. >>>>>>>>>>> >>>>>>>>>>> buffer is an object, (it's structure/layout will look a bit like >>>>>>>>>>> it's class declaration, but it's a little more complex than that) >>>>>>>>>>> that was >>>>>>>>>>> allocated somewhere sometime, (you can figure out where, but really >>>>>>>>>>> you >>>>>>>>>>> don't need to, for this purpose it's just an object) >>>>>>>>>>> data is a member of that object, that points to some memory >>>>>>>>>>> (somewhere else, maybe allocated by a different system, in a >>>>>>>>>>> different >>>>>>>>>>> place) >>>>>>>>>>> you have no idea (and you shouldn't need to know, or use the >>>>>>>>>>> information) the "offset" from the buffer-object to the data. They >>>>>>>>>>> are not >>>>>>>>>>> necessarily related, or share the same memory space. (and in most >>>>>>>>>>> cases, >>>>>>>>>>> they're not even real memory addresses, they're more like >>>>>>>>>>> identifiers) >>>>>>>>>>> >>>>>>>>>>> Simple Javascript scripts can look like C sometimes (a few >>>>>>>>>>> variables here and there, a few array creations), but underneath >>>>>>>>>>> it's doing >>>>>>>>>>> a lot more moving things around. >>>>>>>>>>> function x() >>>>>>>>>>> { >>>>>>>>>>> var a = new array(10); >>>>>>>>>>> var b = new array(100); >>>>>>>>>>> } >>>>>>>>>>> This may look like it allocates 2 arrays, but more than likely >>>>>>>>>>> it's doing something radically different with actual memory. >>>>>>>>>>> >>>>>>>>>>> >>>>>>>>>>> > so how can i see the memory management ? >>>>>>>>>>> As I said, you can't see the javascript side so easily (other >>>>>>>>>>> than using the v8 debugging/inspector tools) >>>>>>>>>>> But if you want to see the C-side memory (which MAY be where the >>>>>>>>>>> data that buffer points at came from) you can make your own >>>>>>>>>>> allocator that >>>>>>>>>>> v8 can use. >>>>>>>>>>> If you then breakpoint each call, you'll know when V8 is >>>>>>>>>>> allocating some memory to use (which may or may not be a direct >>>>>>>>>>> object in >>>>>>>>>>> javascript, an array or typed array in javascript may not directly >>>>>>>>>>> allocate >>>>>>>>>>> here) >>>>>>>>>>> >>>>>>>>>>> >>>>>>>>>>> class TV8Allocator : public v8::ArrayBuffer::Allocator >>>>>>>>>>> >>>>>>>>>>> { >>>>>>>>>>> >>>>>>>>>>> public: >>>>>>>>>>> >>>>>>>>>>> virtual void* Allocate(size_t length) override; >>>>>>>>>>> >>>>>>>>>>> virtual void* AllocateUninitialized(size_t length) override; >>>>>>>>>>> >>>>>>>>>>> virtual void Free(void* data, size_t length) override; >>>>>>>>>>> >>>>>>>>>>> }; >>>>>>>>>>> >>>>>>>>>>> >>>>>>>>>>> void* TV8Allocator::Allocate(size_t length) >>>>>>>>>>> >>>>>>>>>>> { >>>>>>>>>>> >>>>>>>>>>> auto* Bytes = new uint8_t[length]; >>>>>>>>>>> >>>>>>>>>>> for ( auto i=0; i<length; i++ ) >>>>>>>>>>> >>>>>>>>>>> Bytes[i] = 0; >>>>>>>>>>> >>>>>>>>>>> return Bytes; >>>>>>>>>>> >>>>>>>>>>> } >>>>>>>>>>> >>>>>>>>>>> >>>>>>>>>>> void* TV8Allocator::AllocateUninitialized(size_t length) >>>>>>>>>>> >>>>>>>>>>> { >>>>>>>>>>> >>>>>>>>>>> auto* Bytes = new uint8_t[length]; >>>>>>>>>>> >>>>>>>>>>> return Bytes; >>>>>>>>>>> >>>>>>>>>>> } >>>>>>>>>>> >>>>>>>>>>> >>>>>>>>>>> void TV8Allocator::Free(void* data, size_t length) >>>>>>>>>>> >>>>>>>>>>> { >>>>>>>>>>> >>>>>>>>>>> auto* data8 = reinterpret_cast<uint8_t*>(data); >>>>>>>>>>> >>>>>>>>>>> delete[] data8; >>>>>>>>>>> >>>>>>>>>>> } >>>>>>>>>>> >>>>>>>>>>> v8::Isolate::CreateParams create_params; >>>>>>>>>>> >>>>>>>>>>> create_params.array_buffer_allocator = &mAllocator; >>>>>>>>>>> >>>>>>>>>>> >>>>>>>>>>> >>>>>>>>>>> > Cause i saw the code but didn't find how it handles all the >>>>>>>>>>> possible javascript i might write into a script file.... >>>>>>>>>>> >>>>>>>>>>> >>>>>>>>>>> Your computer most likely has more memory than you'll ever write >>>>>>>>>>> in a script :) >>>>>>>>>>> >>>>>>>>>>> If you're trying to work out where your script goes... >>>>>>>>>>> arraybuffer isn't the right place. >>>>>>>>>>> >>>>>>>>>>> >>>>>>>>>>> Do you NEED to know? What exactly are you trying to achieve? >>>>>>>>>>> (take a step back from the code and describe what you're trying to >>>>>>>>>>> do; >>>>>>>>>>> >>>>>>>>>>> are you trying to make an app? learn how memory works in c++? >>>>>>>>>>> learn how memory is used in javascript? Why your app uses 1gb of >>>>>>>>>>> memory? >>>>>>>>>>> >>>>>>>>>>> >>>>>>>>>>> >>>>>>>>>>> >>>>>>>>>>> On Monday, 10 September 2018 22:10:54 UTC+1, dan Med wrote: >>>>>>>>>>>> >>>>>>>>>>>> How big is the offset from buffer to data ? >>>>>>>>>>>> const void* Data >>>>>>>>>>>> <https://cs.chromium.org/chromium/src/third_party/blink/renderer/platform/wtf/typed_arrays/array_buffer_builder.h?l=80&gs=kythe%253A%252F%252Fchromium%253Flang%253Dc%25252B%25252B%253Fpath%253Dsrc%252Fthird_party%252Fblink%252Frenderer%252Fplatform%252Fwtf%252Ftyped_arrays%252Farray_buffer_builder.h%2523b8F1aEDx%25252F6En%25252FkOKh2zVkvONjtDNg9gr5KG7gT9XeJk%25253D&gsn=Data&ct=xref_usages>() >>>>>>>>>>>> const { return buffer_ >>>>>>>>>>>> <https://cs.chromium.org/chromium/src/third_party/blink/renderer/platform/wtf/typed_arrays/array_buffer_builder.h?l=94&ct=xref_jump_to_def&gsn=buffer_> >>>>>>>>>>>> -> >>>>>>>>>>>> <https://cs.chromium.org/chromium/src/base/memory/scoped_refptr.h?l=218&ct=xref_jump_to_def&gsn=-%3E> >>>>>>>>>>>> Data >>>>>>>>>>>> <https://cs.chromium.org/chromium/src/third_party/blink/renderer/platform/wtf/typed_arrays/array_buffer.h?l=225&ct=xref_jump_to_def&gsn=Data>(); >>>>>>>>>>>> } >>>>>>>>>>>> >>>>>>>>>>>> sorry for spamming emails, i will try to condensate more >>>>>>>>>>>> >>>>>>>>>>>> Il giorno lun 10 set 2018 alle ore 23:07 dan Med < >>>>>>>>>>>> litoki...@gmail.com> ha scritto: >>>>>>>>>>>> >>>>>>>>>>>>> Cause i saw the code but didn't find how it handles all the >>>>>>>>>>>>> possible javascript i might write into a script file.... >>>>>>>>>>>>> >>>>>>>>>>>>> Il giorno lun 10 set 2018 alle ore 23:06 dan Med < >>>>>>>>>>>>> litoki...@gmail.com> ha scritto: >>>>>>>>>>>>> >>>>>>>>>>>>>> But after using it for a little while, I have found v8 in >>>>>>>>>>>>>> general is pretty simple. It provides an interface to C >>>>>>>>>>>>>> functions and >>>>>>>>>>>>>> memory. This is kinda what it's for. >>>>>>>>>>>>>> >>>>>>>>>>>>>> so how can i see the memory management ? >>>>>>>>>>>>>> >>>>>>>>>>>>>> >>>>>>>>>>>>>> Il giorno lun 10 set 2018 alle ore 23:06 dan Med < >>>>>>>>>>>>>> litoki...@gmail.com> ha scritto: >>>>>>>>>>>>>> >>>>>>>>>>>>>>> So, the hole length of this raw memory is set to be Data ? >>>>>>>>>>>>>>> And to use it i should create a view on top of it like with >>>>>>>>>>>>>>> typedarrays? >>>>>>>>>>>>>>> >>>>>>>>>>>>>>> >>>>>>>>>>>>>>> So to call arraybuffer::append i should first, try to make >>>>>>>>>>>>>>> the typed array bigger that action will call the >>>>>>>>>>>>>>> arraybuffer::append ? i >>>>>>>>>>>>>>> didn't ask how memcpy work, i didn't get the Data() thing, in >>>>>>>>>>>>>>> the class >>>>>>>>>>>>>>> that's all. >>>>>>>>>>>>>>> >>>>>>>>>>>>>>> Il giorno lun 10 set 2018 alle ore 22:55 @soylentgraham < >>>>>>>>>>>>>>> gra...@grahamreeves.com> ha scritto: >>>>>>>>>>>>>>> >>>>>>>>>>>>>>>> > How can i understand the structure in memory of an >>>>>>>>>>>>>>>> > arraybuffer and how big is the data field which is pointed >>>>>>>>>>>>>>>> > by this void pointerIt has no structure. It is just a series >>>>>>>>>>>>>>>> > of linear bytes, raw memory, allocated by the memory >>>>>>>>>>>>>>>> > allocator. (If you implement your own memory allocator you >>>>>>>>>>>>>>>> > can catch when this happens)It's just the data(buffer) for >>>>>>>>>>>>>>>> > an array. >>>>>>>>>>>>>>>> > How are they represented in memory....It IS memory. It's >>>>>>>>>>>>>>>> > nothing more (it's an array of bytes) >>>>>>>>>>>>>>>> > How big is the data field ?If by "field", you mean, the data >>>>>>>>>>>>>>>> > buffer... it's Capacity >>>>>>>>>>>>>>>> > <https://cs.chromium.org/chromium/src/third_party/blink/renderer/platform/wtf/typed_arrays/array_buffer_builder.h?l=76&gs=kythe%253A%252F%252Fchromium%253Flang%253Dc%25252B%25252B%253Fpath%253Dsrc%252Fthird_party%252Fblink%252Frenderer%252Fplatform%252Fwtf%252Ftyped_arrays%252Farray_buffer_builder.h%2523kB%25252BJ1WxDvoDqf1c8Tz5Ol3yne4lD03cRpevK2LHMUZk%25253D&gsn=Capacity&ct=xref_usages> >>>>>>>>>>>>>>>> > (capacity is how much it can fit) in length. But not how >>>>>>>>>>>>>>>> > much is being used. (bytes_used) >>>>>>>>>>>>>>>> If you're curious about when memory grows, reallocates, is >>>>>>>>>>>>>>>> written to, accessed... it might be worth setting up your >>>>>>>>>>>>>>>> environment so you can debug it by stepping through the code >>>>>>>>>>>>>>>> as it executes. You can watch memory, (this would show what >>>>>>>>>>>>>>>> memcpy changes) see the values passed around, track when >>>>>>>>>>>>>>>> memory gets allocated etc. >>>>>>>>>>>>>>>> Your questions are a mix of very broad, ("How does v8 work") >>>>>>>>>>>>>>>> and very specific programming questions (what is memcpy() >>>>>>>>>>>>>>>> doing)Broad questions are very hard to answer in general. >>>>>>>>>>>>>>>> ("How does a car work") >>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>> I agree, simply browsing the code doesn't give a good overview >>>>>>>>>>>>>>>> of say, how the javascript compiler works, or how memory is >>>>>>>>>>>>>>>> utilised. (How it is allocated is very simple, on the C/++ >>>>>>>>>>>>>>>> side it doesn't implement any memory management, and the array >>>>>>>>>>>>>>>> buffer/view is a view of the C-side memory)But after using it >>>>>>>>>>>>>>>> for a little while, I have found v8 in general is pretty >>>>>>>>>>>>>>>> simple. It provides an interface to C functions and memory. >>>>>>>>>>>>>>>> This is kinda what it's for. >>>>>>>>>>>>>>>> But the point of v8 is that it does a lot of that for you. I >>>>>>>>>>>>>>>> don't REALLY need to know how the memory is tracked on the >>>>>>>>>>>>>>>> javascript side, it just works (if I'm using the API >>>>>>>>>>>>>>>> correctly)Then again, if you NEED to know how it works for a >>>>>>>>>>>>>>>> specific purpose (very restricted memory, fixing a bug), we >>>>>>>>>>>>>>>> can help you a lot more easily by answering a very specific >>>>>>>>>>>>>>>> question. ("My car's low-oil light is blinking, where do I >>>>>>>>>>>>>>>> fill it up") >>>>>>>>>>>>>>>> If you're just curious as to how the entire v8 engine works... >>>>>>>>>>>>>>>> that's a massive ask. A lot of people work on it, and there is >>>>>>>>>>>>>>>> a lot of work and topics involved.Your best bet is reading the >>>>>>>>>>>>>>>> (limited) documentation on the wiki, and read the blog posts >>>>>>>>>>>>>>>> https://v8project.blogspot.com/ which go into quite a lot of >>>>>>>>>>>>>>>> detail on each post topic.I've not seen any real general >>>>>>>>>>>>>>>> overview (the wiki itself says it's out of date) so, stepping >>>>>>>>>>>>>>>> through all the code as it executes is probably your best bet. >>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>> On Monday, 10 September 2018 21:25:37 UTC+1, dan Med wrote: >>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>> in this snippet for example >>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>> namespace WTF >>>>>>>>>>>>>>>>> <https://cs.chromium.org/chromium/src/third_party/blink/renderer/platform/wtf/typed_arrays/array_buffer_builder.h?l=40&gs=kythe%253A%252F%252Fchromium%253Flang%253Dc%25252B%25252B%2523WTF%252523n%252523namespace&gsn=WTF&ct=xref_usages> >>>>>>>>>>>>>>>>> {// A utility class to build an ArrayBuffer instance. >>>>>>>>>>>>>>>>> Validity must be checked// by isValid() before using an >>>>>>>>>>>>>>>>> instance.class WTF_EXPORT >>>>>>>>>>>>>>>>> <https://cs.chromium.org/chromium/src/third_party/blink/renderer/platform/wtf/wtf_export.h?l=46&ct=xref_jump_to_def&gsn=WTF_EXPORT> >>>>>>>>>>>>>>>>> ArrayBufferBuilder >>>>>>>>>>>>>>>>> <https://cs.chromium.org/chromium/src/third_party/blink/renderer/platform/wtf/typed_arrays/array_buffer_builder.h?l=44&gs=kythe%253A%252F%252Fchromium%253Flang%253Dc%25252B%25252B%253Fpath%253Dsrc%252Fthird_party%252Fblink%252Frenderer%252Fplatform%252Fwtf%252Ftyped_arrays%252Farray_buffer_builder.h%2523ArrayBufferBuilder%25253AWTF%252523c%252523hTnYOn1mFcU%2Bkythe%253A%252F%252Fchromium%253Flang%253Dc%25252B%25252B%253Fpath%253Dsrc%252Fthird_party%252Fblink%252Frenderer%252Fplatform%252Fwtf%252Ftyped_arrays%252Farray_buffer_builder.h%2523NyhHD05MjDx8XOe1m%25252BLqXBLvqdjWPsLmDrRvvmR2Ywk%25253D&gsn=ArrayBufferBuilder&ct=xref_usages> >>>>>>>>>>>>>>>>> final { // Disallow copying since it's expensive and we >>>>>>>>>>>>>>>>> don't want code to do it by // accident. USING_FAST_MALLOC >>>>>>>>>>>>>>>>> <https://cs.chromium.org/chromium/src/third_party/blink/renderer/platform/wtf/allocator.h?l=146&ct=xref_jump_to_def&gsn=USING_FAST_MALLOC>(ArrayBufferBuilder >>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>> <https://cs.chromium.org/chromium/src/third_party/blink/renderer/platform/wtf/typed_arrays/array_buffer_builder.h?l=44&ct=xref_jump_to_def&gsn=ArrayBufferBuilder>); >>>>>>>>>>>>>>>>> public: // Creates an ArrayBufferBuilder using the default >>>>>>>>>>>>>>>>> capacity. ArrayBufferBuilder >>>>>>>>>>>>>>>>> <https://cs.chromium.org/chromium/src/third_party/blink/renderer/platform/wtf/typed_arrays/array_buffer_builder.h?l=51&gs=kythe%253A%252F%252Fchromium%253Flang%253Dc%25252B%25252B%253Fpath%253Dsrc%252Fthird_party%252Fblink%252Frenderer%252Fplatform%252Fwtf%252Ftyped_arrays%252Farray_buffer_builder.h%2523me5JBk4wDIaIJCK86MiUpy%25252BnGYRZwEr0AvVg3KaU0pw%25253D&gsn=ArrayBufferBuilder&ct=xref_usages>(); >>>>>>>>>>>>>>>>> ArrayBufferBuilder >>>>>>>>>>>>>>>>> <https://cs.chromium.org/chromium/src/third_party/blink/renderer/platform/wtf/typed_arrays/array_buffer_builder.h?l=53&gs=kythe%253A%252F%252Fchromium%253Flang%253Dc%25252B%25252B%253Fpath%253Dsrc%252Fthird_party%252Fblink%252Frenderer%252Fplatform%252Fwtf%252Ftyped_arrays%252Farray_buffer_builder.h%2523VW0P45Tk9IGjtOqM%25252B9dHdJ64so3WDAfcY1jNBLt0GNY%25253D&gsn=ArrayBufferBuilder&ct=xref_usages>(unsigned >>>>>>>>>>>>>>>>> capacity >>>>>>>>>>>>>>>>> <https://cs.chromium.org/chromium/src/third_party/blink/renderer/platform/wtf/typed_arrays/array_buffer_builder.h?l=53&gs=kythe%253A%252F%252Fchromium%253Flang%253Dc%25252B%25252B%253Fpath%253Dsrc%252Fthird_party%252Fblink%252Frenderer%252Fplatform%252Fwtf%252Ftyped_arrays%252Farray_buffer_builder.h%2523trfcCH7BPCRWiubGq1QF9bypkCRNYtWGHb2AzglMces%25253D&gsn=capacity&ct=xref_usages>) >>>>>>>>>>>>>>>>> : bytes_used_ >>>>>>>>>>>>>>>>> <https://cs.chromium.org/chromium/src/third_party/blink/renderer/platform/wtf/typed_arrays/array_buffer_builder.h?l=92&ct=xref_jump_to_def&gsn=bytes_used_>(0), >>>>>>>>>>>>>>>>> variable_capacity_ >>>>>>>>>>>>>>>>> <https://cs.chromium.org/chromium/src/third_party/blink/renderer/platform/wtf/typed_arrays/array_buffer_builder.h?l=93&ct=xref_jump_to_def&gsn=variable_capacity_>(true) >>>>>>>>>>>>>>>>> { buffer_ >>>>>>>>>>>>>>>>> <https://cs.chromium.org/chromium/src/third_party/blink/renderer/platform/wtf/typed_arrays/array_buffer_builder.h?l=94&ct=xref_jump_to_def&gsn=buffer_> >>>>>>>>>>>>>>>>> = >>>>>>>>>>>>>>>>> <https://cs.chromium.org/chromium/src/base/memory/scoped_refptr.h?l=226&ct=xref_jump_to_def&gsn=%3D> >>>>>>>>>>>>>>>>> ArrayBuffer >>>>>>>>>>>>>>>>> <https://cs.chromium.org/chromium/src/third_party/blink/renderer/platform/wtf/typed_arrays/array_buffer.h?l=42&ct=xref_jump_to_def&gsn=ArrayBuffer>::Create >>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>> <https://cs.chromium.org/chromium/src/third_party/blink/renderer/platform/wtf/typed_arrays/array_buffer.h?l=125&ct=xref_jump_to_def&gsn=Create>(capacity >>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>> <https://cs.chromium.org/chromium/src/third_party/blink/renderer/platform/wtf/typed_arrays/array_buffer_builder.h?l=53&ct=xref_jump_to_def&gsn=capacity>, >>>>>>>>>>>>>>>>> 1); } bool IsValid >>>>>>>>>>>>>>>>> <https://cs.chromium.org/chromium/src/third_party/blink/renderer/platform/wtf/typed_arrays/array_buffer_builder.h?l=58&gs=kythe%253A%252F%252Fchromium%253Flang%253Dc%25252B%25252B%253Fpath%253Dsrc%252Fthird_party%252Fblink%252Frenderer%252Fplatform%252Fwtf%252Ftyped_arrays%252Farray_buffer_builder.h%2523Bx72YH%25252BiA4nF5ZIPsFhA9MQpdVCDOCRHSZa0Ksg6Wp4%25253D&gsn=IsValid&ct=xref_usages>() >>>>>>>>>>>>>>>>> const { return buffer_ >>>>>>>>>>>>>>>>> <https://cs.chromium.org/chromium/src/third_party/blink/renderer/platform/wtf/typed_arrays/array_buffer_builder.h?l=94&ct=xref_jump_to_def&gsn=buffer_>.get >>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>> <https://cs.chromium.org/chromium/src/base/memory/scoped_refptr.h?l=211&ct=xref_jump_to_def&gsn=get>(); >>>>>>>>>>>>>>>>> } // Appending empty data is not allowed. unsigned Append >>>>>>>>>>>>>>>>> <https://cs.chromium.org/chromium/src/third_party/blink/renderer/platform/wtf/typed_arrays/array_buffer_builder.h?l=61&gs=kythe%253A%252F%252Fchromium%253Flang%253Dc%25252B%25252B%253Fpath%253Dsrc%252Fthird_party%252Fblink%252Frenderer%252Fplatform%252Fwtf%252Ftyped_arrays%252Farray_buffer_builder.h%2523BHKR8BlIFhr03faCJF5mu7RDXZ%25252FPtZDAlnACyKmv1XM%25253D&gsn=Append&ct=xref_usages>(const >>>>>>>>>>>>>>>>> char* data >>>>>>>>>>>>>>>>> <https://cs.chromium.org/chromium/src/third_party/blink/renderer/platform/wtf/typed_arrays/array_buffer_builder.h?l=61&gs=kythe%253A%252F%252Fchromium%253Flang%253Dc%25252B%25252B%253Fpath%253Dsrc%252Fthird_party%252Fblink%252Frenderer%252Fplatform%252Fwtf%252Ftyped_arrays%252Farray_buffer_builder.h%25233VvJP%25252BUI3abzouA4%25252FYSBHt09pw3AiNI9e9QAJGooqYI%25253D&gsn=data&ct=xref_usages>, >>>>>>>>>>>>>>>>> unsigned length >>>>>>>>>>>>>>>>> <https://cs.chromium.org/chromium/src/third_party/blink/renderer/platform/wtf/typed_arrays/array_buffer_builder.h?l=61&gs=kythe%253A%252F%252Fchromium%253Flang%253Dc%25252B%25252B%253Fpath%253Dsrc%252Fthird_party%252Fblink%252Frenderer%252Fplatform%252Fwtf%252Ftyped_arrays%252Farray_buffer_builder.h%2523xOZXOK9mCrzsbUtqCxdbDuLg939IJhl7gbf0EykKwnY%25253D&gsn=length&ct=xref_usages>); >>>>>>>>>>>>>>>>> // Returns the accumulated data as an ArrayBuffer instance. >>>>>>>>>>>>>>>>> If needed, // creates a new ArrayBuffer instance and copies >>>>>>>>>>>>>>>>> contents from the internal // buffer to it. Otherwise, >>>>>>>>>>>>>>>>> returns a RefPtr pointing to the internal // buffer. >>>>>>>>>>>>>>>>> scoped_refptr >>>>>>>>>>>>>>>>> <https://cs.chromium.org/chromium/src/base/memory/scoped_refptr.h?l=167&ct=xref_jump_to_def&gsn=scoped_refptr><ArrayBuffer >>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>> <https://cs.chromium.org/chromium/src/third_party/blink/renderer/platform/wtf/typed_arrays/array_buffer.h?l=42&ct=xref_jump_to_def&gsn=ArrayBuffer>> >>>>>>>>>>>>>>>>> ToArrayBuffer >>>>>>>>>>>>>>>>> <https://cs.chromium.org/chromium/src/third_party/blink/renderer/platform/wtf/typed_arrays/array_buffer_builder.h?l=67&gs=kythe%253A%252F%252Fchromium%253Flang%253Dc%25252B%25252B%253Fpath%253Dsrc%252Fthird_party%252Fblink%252Frenderer%252Fplatform%252Fwtf%252Ftyped_arrays%252Farray_buffer_builder.h%2523JX559OA9Zt0rALNU4DOTOkzcmtws4U5V42xhN0rrbow%25253D&gsn=ToArrayBuffer&ct=xref_usages>(); >>>>>>>>>>>>>>>>> // Converts the accumulated data into a String using the >>>>>>>>>>>>>>>>> default encoding. String >>>>>>>>>>>>>>>>> <https://cs.chromium.org/chromium/src/third_party/blink/renderer/platform/wtf/text/wtf_string.h?l=64&ct=xref_jump_to_def&gsn=String> >>>>>>>>>>>>>>>>> ToString >>>>>>>>>>>>>>>>> <https://cs.chromium.org/chromium/src/third_party/blink/renderer/platform/wtf/typed_arrays/array_buffer_builder.h?l=70&gs=kythe%253A%252F%252Fchromium%253Flang%253Dc%25252B%25252B%253Fpath%253Dsrc%252Fthird_party%252Fblink%252Frenderer%252Fplatform%252Fwtf%252Ftyped_arrays%252Farray_buffer_builder.h%2523VMCyw7t%25252FF0UIo65pz8LTbfX5k5G4pIXrUNQbDNKDjaE%25253D&gsn=ToString&ct=xref_usages>(); >>>>>>>>>>>>>>>>> // Number of bytes currently accumulated. unsigned >>>>>>>>>>>>>>>>> ByteLength >>>>>>>>>>>>>>>>> <https://cs.chromium.org/chromium/src/third_party/blink/renderer/platform/wtf/typed_arrays/array_buffer_builder.h?l=73&gs=kythe%253A%252F%252Fchromium%253Flang%253Dc%25252B%25252B%253Fpath%253Dsrc%252Fthird_party%252Fblink%252Frenderer%252Fplatform%252Fwtf%252Ftyped_arrays%252Farray_buffer_builder.h%2523P5Klo%25252BJeJiug%25252FrSAfsaHI8wAnW8h5UBg2%25252BoJByO85kA%25253D&gsn=ByteLength&ct=xref_usages>() >>>>>>>>>>>>>>>>> const { return bytes_used_ >>>>>>>>>>>>>>>>> <https://cs.chromium.org/chromium/src/third_party/blink/renderer/platform/wtf/typed_arrays/array_buffer_builder.h?l=92&ct=xref_jump_to_def&gsn=bytes_used_>; >>>>>>>>>>>>>>>>> } // Number of bytes allocated. unsigned Capacity >>>>>>>>>>>>>>>>> <https://cs.chromium.org/chromium/src/third_party/blink/renderer/platform/wtf/typed_arrays/array_buffer_builder.h?l=76&gs=kythe%253A%252F%252Fchromium%253Flang%253Dc%25252B%25252B%253Fpath%253Dsrc%252Fthird_party%252Fblink%252Frenderer%252Fplatform%252Fwtf%252Ftyped_arrays%252Farray_buffer_builder.h%2523kB%25252BJ1WxDvoDqf1c8Tz5Ol3yne4lD03cRpevK2LHMUZk%25253D&gsn=Capacity&ct=xref_usages>() >>>>>>>>>>>>>>>>> const { return buffer_ >>>>>>>>>>>>>>>>> <https://cs.chromium.org/chromium/src/third_party/blink/renderer/platform/wtf/typed_arrays/array_buffer_builder.h?l=94&ct=xref_jump_to_def&gsn=buffer_>-> >>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>> <https://cs.chromium.org/chromium/src/base/memory/scoped_refptr.h?l=218&ct=xref_jump_to_def&gsn=-%3E>ByteLength >>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>> <https://cs.chromium.org/chromium/src/third_party/blink/renderer/platform/wtf/typed_arrays/array_buffer.h?l=249&ct=xref_jump_to_def&gsn=ByteLength>(); >>>>>>>>>>>>>>>>> } void ShrinkToFit >>>>>>>>>>>>>>>>> <https://cs.chromium.org/chromium/src/third_party/blink/renderer/platform/wtf/typed_arrays/array_buffer_builder.h?l=78&gs=kythe%253A%252F%252Fchromium%253Flang%253Dc%25252B%25252B%253Fpath%253Dsrc%252Fthird_party%252Fblink%252Frenderer%252Fplatform%252Fwtf%252Ftyped_arrays%252Farray_buffer_builder.h%2523WBvAUuWtgva6ffSXIiEGEkt%25252FFFbeCcQcsCz5E%25252FHCKOo%25253D&gsn=ShrinkToFit&ct=xref_usages>(); >>>>>>>>>>>>>>>>> const void* Data >>>>>>>>>>>>>>>>> <https://cs.chromium.org/chromium/src/third_party/blink/renderer/platform/wtf/typed_arrays/array_buffer_builder.h?l=80&gs=kythe%253A%252F%252Fchromium%253Flang%253Dc%25252B%25252B%253Fpath%253Dsrc%252Fthird_party%252Fblink%252Frenderer%252Fplatform%252Fwtf%252Ftyped_arrays%252Farray_buffer_builder.h%2523b8F1aEDx%25252F6En%25252FkOKh2zVkvONjtDNg9gr5KG7gT9XeJk%25253D&gsn=Data&ct=xref_usages>() >>>>>>>>>>>>>>>>> const { return buffer_ >>>>>>>>>>>>>>>>> <https://cs.chromium.org/chromium/src/third_party/blink/renderer/platform/wtf/typed_arrays/array_buffer_builder.h?l=94&ct=xref_jump_to_def&gsn=buffer_>-> >>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>> <https://cs.chromium.org/chromium/src/base/memory/scoped_refptr.h?l=218&ct=xref_jump_to_def&gsn=-%3E>Data >>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>> <https://cs.chromium.org/chromium/src/third_party/blink/renderer/platform/wtf/typed_arrays/array_buffer.h?l=225&ct=xref_jump_to_def&gsn=Data>(); >>>>>>>>>>>>>>>>> } // If set to false, the capacity won't be expanded and >>>>>>>>>>>>>>>>> when appended data // overflows, the overflowed part will be >>>>>>>>>>>>>>>>> dropped. void SetVariableCapacity >>>>>>>>>>>>>>>>> <https://cs.chromium.org/chromium/src/third_party/blink/renderer/platform/wtf/typed_arrays/array_buffer_builder.h?l=84&gs=kythe%253A%252F%252Fchromium%253Flang%253Dc%25252B%25252B%253Fpath%253Dsrc%252Fthird_party%252Fblink%252Frenderer%252Fplatform%252Fwtf%252Ftyped_arrays%252Farray_buffer_builder.h%25232ib6USbezkKcLs8hjPaCz4GUGrUHdD%25252BeN%25252FKenERnRLA%25253D&gsn=SetVariableCapacity&ct=xref_usages>(bool >>>>>>>>>>>>>>>>> value >>>>>>>>>>>>>>>>> <https://cs.chromium.org/chromium/src/third_party/blink/renderer/platform/wtf/typed_arrays/array_buffer_builder.h?l=84&gs=kythe%253A%252F%252Fchromium%253Flang%253Dc%25252B%25252B%253Fpath%253Dsrc%252Fthird_party%252Fblink%252Frenderer%252Fplatform%252Fwtf%252Ftyped_arrays%252Farray_buffer_builder.h%2523vUjrriXMW5FurGjU87jcAlZRQs3b8JSgA4Tt1xrSq7I%25253D&gsn=value&ct=xref_usages>) >>>>>>>>>>>>>>>>> { variable_capacity_ >>>>>>>>>>>>>>>>> <https://cs.chromium.org/chromium/src/third_party/blink/renderer/platform/wtf/typed_arrays/array_buffer_builder.h?l=93&ct=xref_jump_to_def&gsn=variable_capacity_> >>>>>>>>>>>>>>>>> = value >>>>>>>>>>>>>>>>> <https://cs.chromium.org/chromium/src/third_party/blink/renderer/platform/wtf/typed_arrays/array_buffer_builder.h?l=84&ct=xref_jump_to_def&gsn=value>; >>>>>>>>>>>>>>>>> } private: // Expands the size of m_buffer to size + >>>>>>>>>>>>>>>>> m_bytesUsed bytes. Returns true // iff successful. If >>>>>>>>>>>>>>>>> reallocation is needed, copies only data in // [0, >>>>>>>>>>>>>>>>> m_bytesUsed) range. bool ExpandCapacity >>>>>>>>>>>>>>>>> <https://cs.chromium.org/chromium/src/third_party/blink/renderer/platform/wtf/typed_arrays/array_buffer_builder.h?l=90&gs=kythe%253A%252F%252Fchromium%253Flang%253Dc%25252B%25252B%253Fpath%253Dsrc%252Fthird_party%252Fblink%252Frenderer%252Fplatform%252Fwtf%252Ftyped_arrays%252Farray_buffer_builder.h%2523szv9AYLlP3J7qhn%25252Fm%25252BJqzPmSgWf45%25252BRVwVxvXDk3WYQ%25253D&gsn=ExpandCapacity&ct=xref_usages>(unsigned >>>>>>>>>>>>>>>>> size >>>>>>>>>>>>>>>>> <https://cs.chromium.org/chromium/src/third_party/blink/renderer/platform/wtf/typed_arrays/array_buffer_builder.h?l=90&gs=kythe%253A%252F%252Fchromium%253Flang%253Dc%25252B%25252B%253Fpath%253Dsrc%252Fthird_party%252Fblink%252Frenderer%252Fplatform%252Fwtf%252Ftyped_arrays%252Farray_buffer_builder.h%2523mXwymG5xtblCCeS4C9QcnmOwJxql8nYDr2HLqNZVJ8I%25253D&gsn=size&ct=xref_usages>); >>>>>>>>>>>>>>>>> unsigned bytes_used_ >>>>>>>>>>>>>>>>> <https://cs.chromium.org/chromium/src/third_party/blink/renderer/platform/wtf/typed_arrays/array_buffer_builder.h?l=92&gs=kythe%253A%252F%252Fchromium%253Flang%253Dc%25252B%25252B%253Fpath%253Dsrc%252Fthird_party%252Fblink%252Frenderer%252Fplatform%252Fwtf%252Ftyped_arrays%252Farray_buffer_builder.h%2523x95FyaH%25252BSeW1SF4BFhX9oIq7qgtHy3xzXCMmc37LcL8%25253D&gsn=bytes_used_&ct=xref_usages>; >>>>>>>>>>>>>>>>> bool variable_capacity_ >>>>>>>>>>>>>>>>> <https://cs.chromium.org/chromium/src/third_party/blink/renderer/platform/wtf/typed_arrays/array_buffer_builder.h?l=93&gs=kythe%253A%252F%252Fchromium%253Flang%253Dc%25252B%25252B%253Fpath%253Dsrc%252Fthird_party%252Fblink%252Frenderer%252Fplatform%252Fwtf%252Ftyped_arrays%252Farray_buffer_builder.h%2523FKWGJXbcZ%25252BRuy6YD7uxQ765XV8Mhciv4FM%25252FF5B3bNvU%25253D&gsn=variable_capacity_&ct=xref_usages>; >>>>>>>>>>>>>>>>> scoped_refptr >>>>>>>>>>>>>>>>> <https://cs.chromium.org/chromium/src/base/memory/scoped_refptr.h?l=167&ct=xref_jump_to_def&gsn=scoped_refptr><ArrayBuffer >>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>> <https://cs.chromium.org/chromium/src/third_party/blink/renderer/platform/wtf/typed_arrays/array_buffer.h?l=42&ct=xref_jump_to_def&gsn=ArrayBuffer>> >>>>>>>>>>>>>>>>> buffer_ >>>>>>>>>>>>>>>>> <https://cs.chromium.org/chromium/src/third_party/blink/renderer/platform/wtf/typed_arrays/array_buffer_builder.h?l=94&gs=kythe%253A%252F%252Fchromium%253Flang%253Dc%25252B%25252B%253Fpath%253Dsrc%252Fthird_party%252Fblink%252Frenderer%252Fplatform%252Fwtf%252Ftyped_arrays%252Farray_buffer_builder.h%2523aFDjYtlmS2tmLXL2XyJ158HoigBmsAdzguhOSb6XQIw%25253D&gsn=buffer_&ct=xref_usages>; >>>>>>>>>>>>>>>>> DISALLOW_COPY_AND_ASSIGN >>>>>>>>>>>>>>>>> <https://cs.chromium.org/chromium/src/base/macros.h?l=33&ct=xref_jump_to_def&gsn=DISALLOW_COPY_AND_ASSIGN>(ArrayBufferBuilder >>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>> <https://cs.chromium.org/chromium/src/third_party/blink/renderer/platform/wtf/typed_arrays/array_buffer_builder.h?l=96&gs=kythe%253A%252F%252Fchromium%253Flang%253Dc%25252B%25252B%253Fpath%253Dsrc%252Fthird_party%252Fblink%252Frenderer%252Fplatform%252Fwtf%252Ftyped_arrays%252Farray_buffer_builder.h%2523E6nSXqAY3ipexrHDKPfjzHqWqWIsAlT3EH3KVhT57GQ%25253D&gsn=ArrayBufferBuilder&ct=xref_usages>);};} >>>>>>>>>>>>>>>>> // namespace WTF >>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>> How can i understand the structure in memory of an >>>>>>>>>>>>>>>>> arraybuffer and how big is the data field which is pointed by >>>>>>>>>>>>>>>>> this void pointerHow are they represented in memory....How >>>>>>>>>>>>>>>>> big is the data field ? >>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>> Il giorno lun 10 set 2018 alle ore 22:19 dan Med < >>>>>>>>>>>>>>>>> litoki...@gmail.com> ha scritto: >>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>> i already did that and btw it is under the WTF/webkit . >>>>>>>>>>>>>>>>>> I'm interested how v8 handles javascript into every >>>>>>>>>>>>>>>>>> detail if u can guide me... >>>>>>>>>>>>>>>>>> Tell me which repository are being used by v8 on the >>>>>>>>>>>>>>>>>> related topic that would help me really much. >>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>> By when it is called i mean, which javascript code will >>>>>>>>>>>>>>>>>> enable me to call that funciton cause if u click u can't go >>>>>>>>>>>>>>>>>> any further >>>>>>>>>>>>>>>>>> than that, >>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>> Il giorno lun 10 set 2018 alle ore 21:53 Jakob Kummerow < >>>>>>>>>>>>>>>>>> jkum...@chromium.org> ha scritto: >>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>>> On Mon, Sep 10, 2018 at 12:22 PM dan Med < >>>>>>>>>>>>>>>>>>> litoki...@gmail.com> wrote: >>>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>>>> I don't quite see if this google group is useful or >>>>>>>>>>>>>>>>>>>> not, everybody keeps answering me with superficial things, >>>>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>>> You said you wanted to read the compiler's source but >>>>>>>>>>>>>>>>>>> couldn't find it, so I told you that it's in src/compiler/. >>>>>>>>>>>>>>>>>>> If that was not >>>>>>>>>>>>>>>>>>> the answer you wanted, then try asking a different question? >>>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>>> Please also keep in mind that people's time is limited. >>>>>>>>>>>>>>>>>>> The easier/quicker it is to answer your question, the more >>>>>>>>>>>>>>>>>>> likely you are >>>>>>>>>>>>>>>>>>> to get an answer. >>>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>>> i don't care about the trminology like tell me which >>>>>>>>>>>>>>>>>>>> allocator it uses when and why or at least if there's >>>>>>>>>>>>>>>>>>>> something i can read >>>>>>>>>>>>>>>>>>>> to understand..... >>>>>>>>>>>>>>>>>>>> I'm surprised u don't know what a JIT page is, >>>>>>>>>>>>>>>>>>>> basically if you call a function foo() let's say 100 times >>>>>>>>>>>>>>>>>>>> then v8,had >>>>>>>>>>>>>>>>>>>> enough time to understand the parameters given to that >>>>>>>>>>>>>>>>>>>> specific function >>>>>>>>>>>>>>>>>>>> and how to optimize it efficently based on it's >>>>>>>>>>>>>>>>>>>> prediction/observation. >>>>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>>>> I'm not interested in the terminology of things, >>>>>>>>>>>>>>>>>>>> (that's just a matter of reading the source code ) i'm >>>>>>>>>>>>>>>>>>>> more in reading how >>>>>>>>>>>>>>>>>>>> it works when and why.. >>>>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>>> It's great that you want to understand how things work. >>>>>>>>>>>>>>>>>>> Terminology is an important aspect of that though, because >>>>>>>>>>>>>>>>>>> it enables >>>>>>>>>>>>>>>>>>> communication. If we use different words for the same >>>>>>>>>>>>>>>>>>> thing, we won't >>>>>>>>>>>>>>>>>>> understand each other. >>>>>>>>>>>>>>>>>>> Based on your explanation, I'm guessing that by "JIT >>>>>>>>>>>>>>>>>>> page" you mean "the strategy V8 uses to select functions >>>>>>>>>>>>>>>>>>> for optimization". >>>>>>>>>>>>>>>>>>> The core of that logic is in MarkCandidatesForOptimization >>>>>>>>>>>>>>>>>>> in >>>>>>>>>>>>>>>>>>> src/runtime-profiler.cc. >>>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>>>> For example when is ArrayBufferBuilder::Append called >>>>>>>>>>>>>>>>>>>> ?? >>>>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>>> I don't know; it's not part of V8. But you can use Code >>>>>>>>>>>>>>>>>>> Search to find out where anything is called, just click the >>>>>>>>>>>>>>>>>>> function in >>>>>>>>>>>>>>>>>>> question to get a list of call sites: >>>>>>>>>>>>>>>>>>> https://cs.chromium.org/chromium/src/third_party/blink/renderer/platform/wtf/typed_arrays/array_buffer_builder.h?q=ArrayBufferBuilder&sq=package:chromium&g=0&l=61 >>>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>>>> And i thing i've looked at the entire v8 source code >>>>>>>>>>>>>>>>>>>> but didn't find much, apart from the array.js file which >>>>>>>>>>>>>>>>>>>> describes some >>>>>>>>>>>>>>>>>>>> javascript function, i don't understand where's the >>>>>>>>>>>>>>>>>>>> rest.... >>>>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>>> Il giorno lun 10 set 2018 alle ore 20:45 Jakob Kummerow < >>>>>>>>>>>>>>>>>>>> jkum...@chromium.org> ha scritto: >>>>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>>>>> On Sun, Sep 9, 2018 at 8:54 AM dan Med < >>>>>>>>>>>>>>>>>>>>> litoki...@gmail.com> wrote: >>>>>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>>>>>> Oh and one more thing, i've surfed perhaps the entire >>>>>>>>>>>>>>>>>>>>>> source code of v8 at least the interesting parts, but >>>>>>>>>>>>>>>>>>>>>> what i came across >>>>>>>>>>>>>>>>>>>>>> was just very short code execpt for some builtins >>>>>>>>>>>>>>>>>>>>>> written in javascript i >>>>>>>>>>>>>>>>>>>>>> believe, can't find all of the things i've found on the >>>>>>>>>>>>>>>>>>>>>> documentation such >>>>>>>>>>>>>>>>>>>>>> as the interpreter >>>>>>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>>>>> src/interpreter/ >>>>>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>>>>>> and the JIT compilers, >>>>>>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>>>>> src/compiler/ >>>>>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>>>>>> one more thing i'd like to understand how the memory >>>>>>>>>>>>>>>>>>>>>> is handeled like how can i read about the JIT pages, >>>>>>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>>>>> What's a JIT page? >>>>>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>>>>>> or which memory allocator does v8 use >>>>>>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>>>>> It uses several allocation techniques for different >>>>>>>>>>>>>>>>>>>>> purposes. >>>>>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>>>>>> and it's garbage collector >>>>>>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>>>>> src/heap/ >>>>>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>>>>>> Thank you ! >>>>>>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>>>>>> Il giorno dom 9 set 2018 alle ore 17:51 dan Med < >>>>>>>>>>>>>>>>>>>>>> litoki...@gmail.com> ha scritto: >>>>>>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>>>>>>> I don't have understood this part, let me explain it >>>>>>>>>>>>>>>>>>>>>>> to you. >>>>>>>>>>>>>>>>>>>>>>> This is how i get it tell me if i'm wrong at any >>>>>>>>>>>>>>>>>>>>>>> part. >>>>>>>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>>>>>>> I need to understand how is the structure in memory >>>>>>>>>>>>>>>>>>>>>>> of the arraybuffer how is it represented and if the >>>>>>>>>>>>>>>>>>>>>>> data of the array are >>>>>>>>>>>>>>>>>>>>>>> directly stored at an offset accessed by buffer_ -> >>>>>>>>>>>>>>>>>>>>>>> data(). >>>>>>>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>>>>>>> before the call to expand capacity it does create an >>>>>>>>>>>>>>>>>>>>>>> array >>>>>>>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>>>>>>> the arraybuffer in src >>>>>>>>>>>>>>>>>>>>>>> <https://cs.chromium.org/chromium/src/>/third_party >>>>>>>>>>>>>>>>>>>>>>> <https://cs.chromium.org/chromium/src/third_party/>/ >>>>>>>>>>>>>>>>>>>>>>> blink >>>>>>>>>>>>>>>>>>>>>>> <https://cs.chromium.org/chromium/src/third_party/blink/> >>>>>>>>>>>>>>>>>>>>>>> /renderer >>>>>>>>>>>>>>>>>>>>>>> <https://cs.chromium.org/chromium/src/third_party/blink/renderer/> >>>>>>>>>>>>>>>>>>>>>>> /platform >>>>>>>>>>>>>>>>>>>>>>> <https://cs.chromium.org/chromium/src/third_party/blink/renderer/platform/> >>>>>>>>>>>>>>>>>>>>>>> /wtf >>>>>>>>>>>>>>>>>>>>>>> <https://cs.chromium.org/chromium/src/third_party/blink/renderer/platform/wtf/> >>>>>>>>>>>>>>>>>>>>>>> / >>>>>>>>>>>>>>>>>>>>>>> <https://cs.chromium.org/chromium/src/third_party/blink/renderer/platform/wtf/typed_arrays/> >>>>>>>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>>>>>> -- -- v8-users mailing list v8-users@googlegroups.com http://groups.google.com/group/v8-users --- You received this message because you are subscribed to the Google Groups "v8-users" group. 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