[lldb][swift] Implement async funclet comparison based on mangling #9441
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
This will enable reuse of this function in a subsequent commit.
felipepiovezan
commented
Oct 17, 2024
| CheckGroupOfFuncletsFromDifferentFunctions(nested2_funclets1, | ||
| nested2_funclets_top_not_async); | ||
| CheckGroupOfFuncletsFromDifferentFunctions(nested2_funclets2, | ||
| nested2_funclets_top_not_async); |
There was a problem hiding this comment.
I know this might seem like a lot of pairwise checks, but this entire test runs in under 5ms on a debug build of the binary.
felipepiovezan
requested review from
kastiglione,
adrian-prantl and
jimingham
felipepiovezan
commented
Oct 17, 2024
felipepiovezan
commented
Oct 17, 2024
lldb/source/Plugins/LanguageRuntime/Swift/SwiftLanguageRuntime.h
Outdated
Show resolved
Hide resolved
felipepiovezan
force-pushed
the
felipe/swift_compare_async_funclets
branch
from
f2e1217 to
3599daa
Compare
| /// async function. | ||
| /// If either SymbolContext is not a funclets, nullopt is returned. | ||
| std::optional<bool> | ||
| AreEquivalentFunctions(const SymbolContext &sc1, |
There was a problem hiding this comment.
The name of this function doesn't describe well what it does.
Also not great: AsyncFuncletsOfSameFunction?
There was a problem hiding this comment.
The name of this function doesn't describe well what it does.
Also not great:
AsyncFuncletsOfSameFunction?
We're renaming it on the upstream PR that introduces the base class interface (see the PR linked previously: llvm#112720)
There was a problem hiding this comment.
Where is this used?
See the upstream PR, it is used by the thread plan
| /// If name1 and name2 are both mangled names of async functions, return true | ||
| /// iff both correspond to funclets of the same function. | ||
| static FuncletComparisonResult | ||
| AreFuncletsOfSameAsyncFunction(StringRef name1, StringRef name2); |
felipepiovezan
force-pushed
the
felipe/swift_compare_async_funclets
branch
2 times, most recently
from
b407672 to
56b8086
Compare
This is going to be useful for the Swift Language plugin to identify whether two symbol contexts are equivalent, an operation which is done by thread plans such as ThreadPlanStepOverRange. The implementation compares the following attributes of the mangling tree: * If these funclets come from a simple async function (as opposed to a closure), we compare the "Function" child node in the tree. * If these funclets come from an async closure: ** Their "Number" child node must be the same. This number distinguishes different closures in the same scope. ** The closure type must be the same. ** If they have a parent closure, it must be identical. ** If they have a parent function, it must be identical.
This checks whether the two provided symbol contexts refer to funclets of the same async function. In particular, this fixes an issue in the ThreadPlanStepOverRange algorithm for async functions. When the plan stops, it compares the current symbol context to the symbol context of where it started. An initial comparison is done through StackIDs. If that comparison says the two are equal, the plan then attempts to confirm the two SymbolContexts are the same by checking whether the underlying functions are the same. Because different funclets correspond to different low level functions, this comparison was failing.
felipepiovezan
force-pushed
the
felipe/swift_compare_async_funclets
branch
from
56b8086 to
063abb3
Compare
adrian-prantl
approved these changes
Oct 21, 2024
|
@swift-ci test |
|
@swift-ci test platform windows |
|
@swift-ci test windows platform |
felipepiovezan
merged commit 6c40897
into
swiftlang:stable/20240723
2 of 3 checks passed
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.
This PR implements the language plugin changes required to detect whether two funclets belong to the same function. In particular, this fixes an issue where ThreadPlanStepOverRange behaved incorrectly as it believed two virtual frames were different when they were, in fact, the same.
It depends on the upstream change: llvm#112720
Please review each commit on its own