Cranelift: Adjust virtual SP after tail call-conv callees return#6586
Merged
Conversation
fitzgen
force-pushed
the
call-pop-virtual-sp
branch
from
b20b4cb to
b2e56a0
Compare
Callees that use the `tail` calling convention will pop stack arguments from the stack for their callers. They do not, however, adjust the caller's virtual SP, so that still needs to happen in our ABI and `CallSite` code. This is, however, slightly trickier than just emitting a nominal SP adjustment pseudo-instruction because we cannot let regalloc attempt to spill or reload values between the call and the SP adjustment because the stack offsets will be off by the size of the stack arguments to the call. Therefore, we add the number of bytes that the callee pops to the `CallInfo` structures and have emission update the virtual SP atomically with regards to the call itself. Fixes bytecodealliance#6581 Fixes bytecodealliance#6582 Co-Authored-By: Jamey Sharp <jsharp@fastly.com>
fitzgen
force-pushed
the
call-pop-virtual-sp
branch
from
b2e56a0 to
5a10b14
Compare
github-actions
Bot
added
cranelift
Subscribe to Label ActionDetailsThis issue or pull request has been labeled: "cranelift", "cranelift:area:aarch64", "cranelift:area:machinst", "cranelift:area:x64", "winch"Thus the following users have been cc'd because of the following labels:
To subscribe or unsubscribe from this label, edit the |
Member
Author
|
Added support for |
cfallin
approved these changes
Jun 15, 2023
Member
cfallin
left a comment
cfallin
left a comment
There was a problem hiding this comment.
Looks right to me! Just one nit below.
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
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
3 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Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be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.
Callees that use the
tailcalling convention will pop stack arguments from the stack for their callers. They do not, however, adjust the caller's virtual SP, so that still needs to happen in our ABI andCallSitecode. This is, however, slightly trickier than just emitting a nominal SP adjustment pseudo-instruction because we cannot let regalloc attempt to spill or reload values between the call and the SP adjustment because the stack offsets will be off by the size of the stack arguments to the call. Therefore, we add the number of bytes that the callee pops to theCallInfostructures and have emission update the virtual SP atomically with regards to the call itself.Fixes #6581
Fixes #6582