863924 - Baldrmonkey: Map our generated Machine Code <=> GCC/Clang Machine Code

Status: RESOLVED WONTFIX

(Core :: JavaScript: WebAssembly, task, P5)

Description

[Sean Stangl [:sstangl]]

Attachment: [WIP] Odin <=> JS mapper, in no particular format.

VTune profiling support from Bug 861440 permits function-level perf comparison between Odin-compiled JS and GCC/Clang-compiled C++, given some amount of manual name mangling. This already works reasonably effectively, but it seems that given a small amount of additional mapping information, we would be able to perform (C++) line-for-line comparisons between the generated native code and the Odin code.

In particular, the following pieces are currently missing:
1. Odin machine code <=> MIR (done, in patch)
2. MIR <=> JS source position (done, in patch)
3. JS <=> C++ (needs Emscripten support, possibly via DWARF or an LLVM intermediary format)
4. C++ <=> machine code (needs a DWARF reader)

This doesn't seem terribly complicated, and may prove useful for Ion and Emscripten improvements.

Comment 1

[BMO Automation]

Per policy at https://wiki.mozilla.org/Bug_Triage/Projects/Bug_Handling/Bug_Husbandry#Inactive_Bugs. If this bug is not an enhancement request or a bug not present in a supported release of Firefox, then it may be reopened.

Comment 2

[Ryan Hunt [:rhunt]]

I don't think we're going to have anyone to work on this anytime soon.