Don't spill operands onto the stack in naked functions #75417
Merged
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This reverts commit 2567074. This commit does not actually fix the problem. It merely removes the name of the argument from the LLVM output. Even without the name, Rust codegen still spills the (nameless) variable onto the stack which is the root cause. The root cause is solved in the next commit.
Currently, the code spills operands onto the stack for the purpose of debuginfo. However, naked functions can only contain an asm block. Therefore, attempting to spill the operands on the stack is undefined behavior. Fixes rust-lang#42779 cc rust-lang#32408
|
r? @oli-obk (rust_highfive has picked a reviewer for you, use r? to override) |
rust-highfive
added
the
S-waiting-on-review
|
Actually we need something even stronger here: we must never emit an |
I agree. However, that should not block this fix, which is needed either way (and currently blocks my day job). |
|
@bors r+ |
|
📌 Commit 050fb38 has been approved by |
bors
added
S-waiting-on-bors
bors
added a commit
to rust-lang-ci/rust
that referenced
this pull request
Aug 14, 2020
Rollup of 12 pull requests Successful merges: - rust-lang#74650 (Correctly parse `{} && false` in tail expression) - rust-lang#75319 (Fix ICE rust-lang#75307 in `format`) - rust-lang#75417 (Don't spill operands onto the stack in naked functions) - rust-lang#75452 (self-profile: Cache more query key strings when doing self-profiling.) - rust-lang#75459 (fix LocalInfo doc comment) - rust-lang#75462 (Remove unused tcx parameter) - rust-lang#75467 (Fix E0741 error code explanation) - rust-lang#75471 (Change registered "program name" for -Cllvm-args usage messages) - rust-lang#75477 (Expand function pointer docs) - rust-lang#75479 (make rustc-docs component available to rustup) - rust-lang#75496 (Prioritization WG: Open Zulip topics only for `I-prioritize` issues) - rust-lang#75500 (Disable zlib in LLVM on aarch64-apple-darwin) Failed merges: r? @ghost
npmccallum
added a commit
to enarx-archive/frenetic2
that referenced
this pull request
Aug 20, 2020
Requires this fix: rust-lang/rust#75417
bstrie
added
the
A-naked
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
Currently, the code spills operands onto the stack for the purpose of
debuginfo. However, naked functions can only contain an asm block. Therefore,
attempting to spill the operands on the stack is undefined behavior.
Fixes #42779
cc #32408
Note that this PR reverts #74105 which ultimately didn't fix the problem.
cc @haraldh @Amanieu @matthewjasper