Fix coroutine layout bug from PR #150116 #150275
Open
Conversation
This file contains hidden or 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
rustbot
added
S-waiting-on-review
Collaborator
|
rustbot has assigned @petrochenkov. Use |
This comment has been minimized.
This comment has been minimized.
This comment has been minimized.
This comment has been minimized.
Author
|
solving issues |
PR rust-lang#150116 introduced a bug in coroutine variant layout by incorrectly keeping the direct construction of `in_memory_order` without adapting it to the new representation. Before PR rust-lang#150116, the code correctly built an inverse mapping indexed by memory position, then inverted it to get the memory_index. After PR rust-lang#150116, the code still built the mapping indexed by memory position (as if it were an inverse mapping), but treated it directly as `in_memory_order` without inversion. This caused incorrect field ordering. The bug manifested as linker errors on PE/COFF targets (e.g., x86_64-unknown-uefi): error: offset is not a multiple of 16 And as ICEs with non-bijective mapping assertions in other cases. Fix by correctly keeping the inverse memory index construction (indexed by memory position), then using it directly as `in_memory_order` since that's what the new representation expects.
leonardocxavier
force-pushed
the
fix-coroutine-memory-index-bug
branch
from
936dc7d to
557616b
Compare
Collaborator
|
Member
|
This looks like #150266 which was closed for not matching our contribution policy 🤔 |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
5 participants
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Outdated suggestions cannot be applied.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.
Summary
This PR fixes a critical bug introduced in PR #150116 that causes linker errors on PE/COFF targets (e.g.,
x86_64-unknown-uefi):Problem
PR #150116 optimized memory layout by inverting the storage representation from
memory_index(source→memory) toin_memory_order(memory→source).However, in
compiler/rustc_abi/src/layout/coroutine.rs(lines 244-276), the code was buildingcombined_in_memory_orderdirectly instead of:combined_memory_index(source→memory) firstin_memory_order(memory→source)This caused fields to be placed at incorrect offsets, violating PE/COFF alignment requirements (16-byte multiples).
Solution
Changed the coroutine layout code to:
combined_memory_indexas an intermediate representationcombined_memory_index[i] = memory_indexcombined_in_memory_order = combined_memory_index.invert_bijective_mapping()Testing
Verified that
rustc_abicompiles successfully with this fix.Impact
x86_64-unknown-uefi)