RFR: 8314265: Fix -Wconversion warnings in miscellaneous runtime code [v4]

[Coleen Phillimore]

On Wed, 16 Aug 2023 23:02:45 GMT, Coleen Phillimore <coleenp at openjdk.org> wrote:

>> src/hotspot/share/utilities/elfFile.cpp line 1723:
>> 
>>> 1721: void DwarfFile::LineNumberProgram::LineNumberProgramState::set_index_register(const uint64_t operation_advance,
>>> 1722:                                                                               const LineNumberProgramHeader& header) {
>>> 1723:   _op_index = (_op_index + operation_advance) % header._maximum_operations_per_instruction;
>> 
>> This should be narrowed by a byte.
>
> So put the cast here?

uint64_t operation_advance;
      if (!_reader.read_uleb128(&operation_advance, 4)) {
        // Must be at most 4 bytes because the index register is only 4 bytes wide.
        return false;
      }
      _state->add_to_address_register(operation_advance, _header);

This is why I changed it.  Should operation_advance be static_cast<uint8_t> here ? This read function reads 64 bits of info.

-------------

PR Review Comment: https://git.openjdk.org/jdk/pull/15233#discussion_r1296522650