[wasm-split] Use a fresh table when reference types are enabled #6726
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Rather than trying to trampoline primary-to-secondary calls through an existing table, just create a fresh table for this purpose. This ensures that modifications to the existing tables cannot interfere with primary-to-secondary calls and conversely that loading the secondary module cannot overwrite modifications to the tables.
kripken
approved these changes
Jul 11, 2024
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Looks like this uncovered an existing bug in how we handled function references in active segments. I'm glad we're going to get fuzzer coverage for this! |
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This change will make primary-to-secondary indirect calls slower because they will now trampoline to a second indirect call made through the fresh table. Perhaps we should consider adding a flag to keep the old behavior for use with Emscripten now that reference-types are on by default? (or will be soon?) But we wouldn't be able to fuzz effectively with that flag enabled, so it would be risky. |
kripken
approved these changes
Jul 11, 2024
|
The extra indirection seems annoying, but yeah, adding a flag would have downsides too. Maybe it's worth measuring though. |
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Rather than trying to trampoline primary-to-secondary calls through an
existing table, just create a fresh table for this purpose. This ensures
that modifications to the existing tables cannot interfere with
primary-to-secondary calls and conversely that loading the secondary
module cannot overwrite modifications to the tables.