[wasm] Pass --table-base to linker to reserve low function addresses #1987
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
WebAssembly does not have a reserved address space by default, so we need to explicitly reserve low addresses for extra inhabitants for enum types with pointer payloads. swiftlang/swift#39300 added `--global-base` to reserve low data addresses, but we also need to reserve low function addresses with `--table-base` for function pointers because WebAssembly uses a separate address space for function pointers.
This was referenced Sep 15, 2025
| @swift-ci test |
MaxDesiatov approved these changes Sep 15, 2025
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
2 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 Outdated suggestions cannot be applied.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.
WebAssembly does not have a reserved address space by default, so we need to explicitly reserve low addresses for extra inhabitants for enum types with pointer payloads. swiftlang/swift#39300 added
--global-baseto reserve low data addresses, but we also need to reserve low function addresses with--table-basefor function pointers because WebAssembly uses a separate address space for function pointers.Corresponding legacy-driver change: swiftlang/swift#84285