JIT does not emit trampolines for jumps to addresses encoded as operands
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interpreter-core
topic-JIT
type-bug
- Dominant language
- Python
- Stars
- 77.2k
- Forks
- 35.9k
- PR merge metrics
- PR metrics pending
Description
Bug report
Bug description:
We need to declare variables volatile here and in https://github.com/python/cpython/pull/148745 otherwise the code generator emits normal jumps without the necessary patching to add trampolines.
For more details see https://github.com/python/cpython/pull/148745#discussion_r3177522254
CPython versions tested on:
CPython main branch
Operating systems tested on:
No response
Contributor guide
First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Start at Python/bytecodes.c around line 5053 and read the discussion in pull request 148745. Trace how the JIT code generator handles jumps whose addresses are operands, then verify that the affected variables preserve the trampoline-patching behavior. Done means such jumps emit the required trampolines on the CPython main branch.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- c, python
- Domain
- compilers
- Issue type
- Bug
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Activity status
- Quiet
- Clarity
- Mostly clear
- Newbie friendliness
- 52/100