StringBuilderSubstringPosition 2477 src/runtime.cc         StringBuilderSubstringPosition::is_valid(from)) {
StringBuilderSubstringPosition 2479 src/runtime.cc           StringBuilderSubstringPosition::encode(from);
StringBuilderSubstringPosition 6870 src/runtime.cc         pos = StringBuilderSubstringPosition::decode(encoded_slice);
StringBuilderSubstringPosition 6939 src/runtime.cc         pos = StringBuilderSubstringPosition::decode(smi_value);