Fix fuzzer generation of a DataSegment + add validation that would have caught it #6626
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| Actually tests pass but the fuzzer fails, so I've missed something... |
| The old code had a second bug - it didn't check for name collisions in the new segment it added. Fixed. |
aheejin approved these changes May 23, 2024
| auto num = upTo(USABLE_MEMORY * 2); | ||
| for (size_t i = 0; i < num; i++) { | ||
| auto value = upTo(512); | ||
| wasm.dataSegments[0]->data.push_back(value >= 256 ? 0 : (value & 0xff)); |
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Was this meant to be wasm.dataSegment[i]? It looks it should've been that way if the semantics are the same with the modified code..
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Hmm, I think it is pushing num chunks of binary data to the first segment here. wasm.dataSegments[i] might not exist - all we know is that [0] exists.
What do you mean by the second sentence?
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Sorry I was confused.. Nevermind.
Co-authored-by: Heejin Ahn <aheejin@gmail.com>
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The DataSegment was manually added to
.dataSegments, but we need to add itusing
addDataSegmentso the maps are updated andgetDataSegment(name)works.
Ideally
.dataSegmentswould be private, but a lot of code finds it useful toiterate on it, so we've left it accessible.
Also add validation that would have caught this earlier: check that each item in
the item lists can be fetched by name.
The reason this was noticed is that #6620 happened to run into it by pure luck.