Chrome Version: 67.0.3396.99 (Official Build) (64-bit)
OS: macOS 10.13.6

What steps will reproduce the problem?

(1) Profile https://webassembly.org/demo/Tanks/ in Chrome Developer Tools

What is the expected result?

I expected function names of the form "wasm-function[\d+]". That's the format that Chrome uses for stack traces (i.e. Error.prototype.stack). It's also the format that Firefox uses for its profiler.

What happens instead?

Every WebAssembly function in Chrome shows up as "<WASM UNNAMED>" instead. This makes it impossible for us to debug the performance of our WebAssembly app.

We have been getting by so far by compiling C++ to JavaScript instead and profiling that, but obviously the performance characteristics are pretty different and we'd like to be able to measure the real thing. For example, the start of JavaScript execution is warped by JIT overhead, which sometimes causes us to mis-prioritize optimizations.

From a tooling perspective, it'd be really straightforward for us to convert the "wasm-function[\d+]" format back to C++ function names since we already have to do that for stack traces anyway.

It seems like this would be really straightforward to do. I think this is the code that causes this:

    Handle<String> WasmModuleObject::GetFunctionName(
        Isolate* isolate, Handle<WasmModuleObject> module_object,
        uint32_t func_index) {
      MaybeHandle<String> name =
          GetFunctionNameOrNull(isolate, module_object, func_index);
      if (!name.is_null()) return name.ToHandleChecked();
      return isolate->factory()->NewStringFromStaticChars("<WASM UNNAMED>");
    }

Just returning "wasm-function[" + func_index + "]" here would make profiling WebAssembly code infinitely more useful in Chrome.