[AST] Reinstate "Fix excessive deserialization in GenericSignatureBuilder" #7530
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
|
@swift-ci please smoke test and merge |
jrose-apple
reviewed
Feb 16, 2017
include/swift/AST/Decl.h
Outdated
| @@ -2854,8 +2854,9 @@ class NominalTypeDecl : public GenericTypeDecl, public IterableDeclContext { | |||
| /// | |||
| /// \param ignoreNewExtensions Whether to avoid loading any new extension. | |||
| /// Used by the module loader to break recursion. | |||
| ArrayRef<ValueDecl *> lookupDirect(DeclName name, | |||
| bool ignoreNewExtensions = false); | |||
| SmallVector<ValueDecl *, 4> lookupDirect( | |||
There was a problem hiding this comment.
I think it makes sense to return a TinyPtrVector here. There are a lot of cases where there's just one element.
There was a problem hiding this comment.
The result of this function is generally stored on the stack, so we're mostly talking saving some stack space (TinyPtrVector is one pointer vs. seven for the SmallVector). I'll make the change, though.
DougGregor
force-pushed
the
generic-signature-deserialization
branch
from
e411d44 to
c001337
Compare
This function was returning an ArrayRef pointing into a data structure that is easily mutated via code walking over that ArrayRef, which could cause spooky side effects, particularly during deserialization. Perform a defensive copy to eliminate such side effects.
…der" This reverts commit d3926d1.
DougGregor
force-pushed
the
generic-signature-deserialization
branch
from
c001337 to
464dac7
Compare
|
@swift-ci please smoke test and merge |
1 similar comment
|
@swift-ci please smoke test and merge |
beccadax
added a commit
to beccadax/swift
that referenced
this pull request
Nov 14, 2018
In swiftlang#7530, NominalTypeDecl::lookupDirect() started returning TinyPtrVector instead of ArrayRef so that it wouldn’t be returning a pointer into a mutable data structure. Unfortunately, some callees assigned its return value into an ArrayRef; C++ happily converted the TinyPtrVector to an ArrayRef and then treated the TinyPtrVector as out-of-scope, so the ArrayRef would now point to an out-of-scope object. Oops.
beccadax
added a commit
to beccadax/swift
that referenced
this pull request
Nov 15, 2018
In swiftlang#7530, NominalTypeDecl::lookupDirect() started returning TinyPtrVector instead of ArrayRef so that it wouldn’t be returning a pointer into a mutable data structure. Unfortunately, some callees assigned its return value into an ArrayRef; C++ happily converted the TinyPtrVector to an ArrayRef and then treated the TinyPtrVector as out-of-scope, so the ArrayRef would now point to an out-of-scope object. Oops.
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.
Try to reinstate @slavapestov 's change to limit deserialization in
GenericSignatureBuilder, with a fix to makeNominalTypeDecl::lookupDirect()defensively copy its result.