Deprecate WasmOffsetConverter?

[RReverser]

Judging by description in

emscripten/src/wasm_offset_converter.js

Lines 13 to 19 in 39d93be

	// The main purpose of this module is to enable the conversion of function
	// index and offset from start of function to an offset into the WASM binary.
	// This is needed to look up the WASM source map as well as generate
	// consistent program counter representations given v8's non-standard
	// WASM stack trace format.
	//
	// v8 bug: https://crbug.com/v8/9172

, it was created to work around a V8 bug that has now been long fixed, so seems like a good candidate for cleanup.

[sbc100]

It looks like we use wasmOffsetConverter both in convertFrameToPC and also in emscripten_pc_get_function. While the former looks like its no longer needed in modern browser I don't quite see how that latter usage could be replaced? Am I missing something?

[RReverser]

I don't quite see how that latter usage could be replaced?

From a quick glance, Wasm functions should be able to use the UNWIND_CACHE mechanism already used by JS functions. It's populated by jsStackTrace() + convertFrameToPC, and the former will return the raw stacktrace for both JS and Wasm frames, while the latter, like you said, can be updated to handle Wasm w/o offset converter.

[RReverser]

Even ignoring caching, here's what the state looks like in emscripten_pc_get_function:

That is, it's just a matter of splitting jsStackTrace() into lines like we do in other places and searching for the line with that 586 hex address, which in this case would be at test_return_address.wasm.main (wasm://wasm/test_return_address.wasm-000a1cc2:wasm-function[10]:0x586).

From that you get the expected Wasm name main (in debug mode).

[RReverser]

In fact, if I forcibly capture the unwind cache via emscripten_stack_snapshot() (IIUC emscripten_pc_get_function is meant to be used only with it anyway), I can see that it already collects Wasm entries too:

So it's just a matter of extracting Wasm function names with separate regex but otherwise similarly to how JS names are already extracted.

Or even leaving the same regex, you'll just get slightly more verbose names like test_return_address.wasm.main but maybe that's fine.