fix(interop): Correctly initialize pointers from numbers on 64-bit archs #1040
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JavaScript represents 64-bit integers as floating point `double` values. This means that the conversion from JSValue to pointer is done by extracting the `double` value and then converting it to integer. **Caution:** This means that pointers with more than 54 significant bits are likely to be rounded and misrepresented! However, current OS and hardware implementations are using 48 bits, so we're safe at the time being. See https://en.wikipedia.org/wiki/X86-64#Virtual_address_space_details and https://en.wikipedia.org/wiki/ARM_architecture#ARMv8-A
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JavaScript represents 64-bit integers as floating point
doublevalues.The conversion from JSValue to pointer must be done by
extracting the
doublevalue and then converting it to integer.Caution: This means that pointers with more than 54 significant bits
are likely to be rounded and misrepresented!
However, current OS and hardware implementations are using 48 bits,
so we're safe at the time being.
See https://en.wikipedia.org/wiki/X86-64#Virtual_address_space_details
and https://en.wikipedia.org/wiki/ARM_architecture#ARMv8-A
PR Checklist
The bug has been discovered while looking for a way to pass pointers to Objective-C objects to workers.
See #620 (comment)