On Wed, 16 Aug 2023 13:01:53 GMT, Christian Hagedorn <chaged...@openjdk.org>
wrote:
>> This code:
>>
>> uint64_t isa;
>> if (!_reader.read_uleb128(&isa, 4)) {
>> // isa register is 4 bytes wide.
>> return false;
>> }
>> _state->_isa = isa; // only save 4 bytes
>>
>> returns 64 bit of information into isa from this read_uleb128 call, even
>> though it passes 4.
>
> I've quickly skimmed through the usages of `read_uleb128`. We only seem to be
> reading either directly into a proper `uint64_t` or we are reading 4 bytes
> (i.e. `check_size = 4`). In the latter case, we could either:
> - add a `static_cast` for the read value when storing it into a 32 bit field,
> as for example for `isa` above (i.e. `_state->_isa =
> static_cast<uint32_t>(isa)`).
> - provide a 32 bit `read_uleb128()` version that hides the casting.
>
> I guess it's fine to just go with a `static_cast` when storing to a field for
> the few cases we have.
Thanks Christian. I'll revert to use the static cast. One of the cases has a
comment why.
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PR Review Comment: https://git.openjdk.org/jdk/pull/15233#discussion_r1295937366
