[wasm] wasm-only exceptions that we do not see in JS mode

[kenzieschmoll]

[mkustermann]

@kenzieschmoll Could you explain how these stack traces are logged, processed before we end up here? Are the real stack traces thrown by V8 non-symbolic (i.e. have offsets in the wasm file) and those are later decoded using source maps?

(I'd assume the stack traces thrown by V8 either have offsets into wasm file or wasm function names, but no file/line information. So that has to come from somewhere)

The stack are somewhat suspicious:

• The first stack would indicate setActivate has to perform a type check (either on parameters or as part of it's body). But looking at the source it doesn't seem like it would have that. Building it locally it also doesn't seem like the wasm code for setActivate has a call to _asInterfaceSubtype0

• The middle stack would indicate that perform called _asSubtype which called _sendData.
  => This stack doesn't make any sense.

• The bottom stack: EngineSceneBuilder.pop() does not have an index check in it. Possibly some code it calls has an index check. If that code was inlined, we'd want to see those inlined frames

[mkustermann]

I think to make progress here we'd want to have

• The unprocessed stack trace from the browser that has wasm offsets in them, it should look like () or (*)
• All build artifacts, including the source maps
• Instructions on how that precise version of DevTools was build, so we can reproduce the build artifacts

(**) Example stack thrown by v8 with symbols (i.e. compiled with --no-strip-wasm)

module0.Error._throwWithCurrentStackTrace (http://.../throw_test.wasm:wasm-function[50]:0x4fa3)
    at module0.bar (http://.../throw_test.wasm:wasm-function[349]:0x8c80)
    at module0.foo (http://.../throw_test.wasm:wasm-function[348]:0x8c74)
    at module0.main (http://.../throw_test.wasm:wasm-function[49]:0x4f98)
    at module0._invokeMain (http://.../throw_test.wasm:wasm-function[41]:0x4ef0)
    at InstantiatedApp.invokeMain (.../throw_test.mjs:231:37)
    at .../test.html
    at dartMainRunner (http://.../test_controller.js:319:5)
    ...

(***) Example stack thrown by v8 without symbols (i.e. compiled with --strip-wasm)

    at http://.../throw_test.wasm:wasm-function[11]:0x997
    at http://.../throw_test.wasm:wasm-function[8]:0x938
    at InstantiatedApp.invokeMain (http://.../throw_test.mjs:231:37)
    at http://.../test.html
    at dartMainRunner (http://.../test_controller.js:319:5)
    ...

[kevmoo]

@elliette to investigate if these are still happening

[elliette]

IndexError:

• Fixed by @biggs0125 in Decrease ring buffer size to 2^31 - 1 which is wasm limit #9341, confirmed that we are no longer seeing it in DevTools 2.49.0.

Runtime type check failed:

• No longer see this error in DevTools 2.48.0 or 2.49.0 (last occurrence was in DevTools 2.47.0). Therefore I think it is safe to assume this was fixed.

I'm not seeing any other exceptions in 2.48.0 / 2.49.0 that we aren't also seeing in dart2js, so I think this issue is safe to close out. Will continue to monitor exceptions are re-open if we encounter anything new here.