One trick you can use (which Chromium+Oilpan uses) is to only GC in between turns of the event loop. In that case, your set of roots is exactly equal to the accessible global variables plus everything accessible from the DOM (including event handlers). In particular, nothing is on the stack, so there is no need to introspect stack frames.
I considered that but I'm worried that won't work with WebAssembly because it's a more memory-constrained environment. Your app may generate a ton of data in a frame and run off the end of the address space. I guess I'm probably just thinking back to asm.js where you sometimes only have 256mb to work with. I'll try this first at least since it makes stuff easier.
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One trick you can use (which Chromium+Oilpan uses) is to only GC in between turns of the event loop. In that case, your set of roots is exactly equal to the accessible global variables plus everything accessible from the DOM (including event handlers). In particular, nothing is on the stack, so there is no need to introspect stack frames.
I considered that but I'm worried that won't work with WebAssembly because it's a more memory-constrained environment. Your app may generate a ton of data in a frame and run off the end of the address space. I guess I'm probably just thinking back to asm.js where you sometimes only have 256mb to work with. I'll try this first at least since it makes stuff easier.
Just go with pure reference counting. It'll be faster and easier.
That's a really clever idea. Thanks for sharing.