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Questions - v8

How does hidden classes really avoid dynamic lookups?

So we have all heard that v8 uses the thing called hidden classes where when many objects have the same shape, they just store a pointer to the shape struct which stores fixed offsets. I have heard th...
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Null

javascript

node.js

optimization

v8

Votes: 0

Answers: 1

Latest Answer

(V8 developer here.) The key is that hidden classes allow caching. So, certainly, a few dynamic lookups will still be required. But thanks to caching, they don't have to be repeated every single time ...
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jmrk

V8 Embedding. Cannot print out the `v8::Local` object

In Short I was trying to print out the v8::Local object content, with either of v8/tools/gdbinit and v8/tools/lldb_commands.py helper scripts, I got Empty Line OR Syntax Error messages. Is there anyth...
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absuu

c++

gdb

v8

lldb

embedded-v8

Votes: 0

Answers: 1

Latest Answer

For debugging, try using a debug build: use gn args <your_output_dir> to set is_debug = true, then recompile. If you insist on debugging release-mode binaries, you can enable jlh and friends wit...
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jmrk

Why cannot v8/nodejs allocate a max-size array if sufficient memory?

I'm aware the maximum length of a JavaScript array is 2^32-1, but regardless of how much memory I permit it will still fail to allocate. What's going on? One-line repro: node --max-old-space-size=1000...
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Aaron

node.js

v8

Votes: 0

Answers: 1

Latest Answer

(V8 developer here.) No, it's not a bug, just an implementation-defined limit. V8 has an internal limit of ~1GB for any individual heap object. At 4 bytes (with pointer compression) per element, that ...
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jmrk

JavaScript: V8 question: are small integers pooled?

was looking at this V8 design doc where it has a section for Constant Pool Entries it says Constant pools are used to store heap objects and small integers that are referenced as constants in generat...
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Joji

javascript

v8

Votes: 0

Answers: 1

Latest Answer

V8 developer here. are small integers pooled or not? They are not (at least not right now). That said, this is a small implementation detail and could be done either way: it would totally be possibl...
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jmrk

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