A collection of hashing improvements from using hashtables. #4094
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LLVM's `APInt` and `APFloat` need specialized handling to be used effectively in hashtables. We can't inject overrides into LLVM so we need to handle them in our hashing routine. There were also problematic limits on hashing pairs and tuples. First, the unique-object-representation hashing of pairs was more restricted than tuples which was a problematic asymmetry and isn't needed. But the larger issue is that we didn't support recursively hashing when necessary. That requires a careful predicate to avoid infinite recursion but lets us handle important use cases for hashtables with a tuple as a key. Also added support for hashing arrays that recurse in addition to arrays where we can hash the raw storage, and added overloads to redirect to common array handling from various array-like types. Last but not least, re-worked the constraint model for hashing as raw data to not override custom hashing functions.
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Co-authored-by: Richard Smith <richard@metafoo.co.uk>
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Co-authored-by: Richard Smith <richard@metafoo.co.uk>
Co-authored-by: Carbon Infra Bot <carbon-external-infra@google.com>
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LLVM's
APIntandAPFloatneed specialized handling to be used effectively in hashtables. We can't inject overrides into LLVM so we need to handle them in our hashing routine.There were also problematic limits on hashing pairs and tuples. First, the unique-object-representation hashing of pairs was more restricted than tuples which was a problematic asymmetry and isn't needed. But the larger issue is that we didn't support recursively hashing when necessary. That requires a careful predicate to avoid infinite recursion but lets us handle important use cases for hashtables with a tuple as a key.
Also added support for hashing arrays that recurse in addition to arrays where we can hash the raw storage, and added overloads to redirect to common array handling from various array-like types.
Last but not least, re-worked the constraint model for hashing as raw data to not override custom hashing functions.