Feature or enhancement

Proposal:

Currently the JIT uop buffer modifies uops traces in place.

I think we should make it add to a new buffer. Having modifications be in-place is making our code messy and full of special cases.

So

REPLACE_OP(this_instr, ...)

should become

ADD_OP(ctx, ...)

in optimizer_bytecodes.c,

Also, the default generated case of optimizer_bytecodes.c should be to ADD_OP(pc, ...)

This is also blocking optimization in #143414, as ocassionally we need to insert extra guards to check the uniqueness of an object for example.

Has this already been discussed elsewhere?

No response given

Links to previous discussion of this feature:

No response

Linked PRs

• gh-143421: Move JitOptContext from stack allocation to per-thread heap allocation to avoid stack overflow. #143536
• gh-143421: Lazily allocate tracer code and opt buffers #143597
• gh-143421: Allocate all JIT state in one go #143626
• gh-143421: Use new buffer to save optimized uops #143682