oxidecomputer / oxidecomputer/hubris
Max Stack Analysis does not account for functions missing `.stack_sizes` info
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- Dominant language
- Rust
- Stars
- 3.6k
- Forks
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- Avg merge
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- Merged PRs (30d)
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Description
The current max-stack code does not account for functions that do not have .stack_sizes metadata provided by LLVM. This includes inline assembly (like system calls), statically linked libraries (like from salty), or compiler-builtins (like memcpy).
I've written a hacky pass to the stack analysis to calculate this: https://github.com/oxidecomputer/hubris/compare/b702011f358a5ddfdfca3a2bd25feb1528deb71c.../james/calculate-stack. If this analysis appears to be sufficient enough, we could potentially remove our dependency on the unstable -Z flags required to make rustc/llvm emit the .stack_sizes section.
CC #2588
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 by reading the current max-stack analysis and comparing it with the linked calculate-stack pass. Trace how functions without LLVM .stack_sizes metadata are handled, including inline assembly, statically linked libraries, and compiler-builtins. Done means the analysis accounts for those functions and confirms whether the unstable Rust flags can be removed.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- rust
- Domain
- compilers, embedded-iot, performance
- Issue type
- Bug
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Activity status
- Quiet
- Clarity
- Mostly clear
- Newbie friendliness
- 48/100