Uh oh!
There was an error while loading. Please reload this page.
[mono][wasm] Rework the handling of GC references in AOTed code. - #59352
Merged
Conversation
Previously, variables holding GC refs were marked volatile so they were loaded/stored to the C stack on every access. Since the stack is conservatively scanned, all the objects pointed to by it are pinned, so there is no need to load them on every access. Instead of marking them as volatile, allocate a 'gc pinning' area on the stack, and store ref variables to it after they are assigned. This improves code size and performance.
vargaz
requested review from
EgorBo, SamMonoRT, imhameed and lambdageek
as code ownersSeptember 20, 2021 16:28
vargaz
commented
Sep 20, 2021
ContributorAuthor
lambdageek
left a comment
Member
There was a problem hiding this comment.
This approach makes sense, but I wonder if LLVM's optimizer will outsmart us.
Also do we want to do this on non-wasm in the future? might avoid some spilling and copy_stack_data?
Uh oh!
There was an error while loading. Please reload this page.
lewing
approved these changes
Sep 21, 2021
imhameed
approved these changes
Sep 21, 2021
radical
commented
Sep 21, 2021
Member
Can this be backported to rc2 too? |
radical
commented
Sep 21, 2021
Member
/backport to release/6.0-rc2 |
Contributor
Started backporting to release/6.0-rc2: https://github.com/dotnet/runtime/actions/runs/1256370822 |
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 freeto subscribe to this conversation on GitHub.
Already have an account?
Sign in.
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Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be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.
Previously, variables holding GC refs were marked volatile so they
were loaded/stored to the C stack on every access. Since the stack
is conservatively scanned, all the objects pointed to by it are pinned,
so there is no need to load them on every access. Instead of
marking them as volatile, allocate a 'gc pinning' area on the stack,
and store ref variables to it after they are assigned. This improves
code size and performance.