diff options
| -rw-r--r-- | runtime/mirror/class.cc | 29 |
1 files changed, 25 insertions, 4 deletions
diff --git a/runtime/mirror/class.cc b/runtime/mirror/class.cc index fe923cbaa6..0bf1b1cc0a 100644 --- a/runtime/mirror/class.cc +++ b/runtime/mirror/class.cc @@ -1173,10 +1173,31 @@ ArtField* Class::FindDeclaredStaticField(std::string_view name, std::string_view } ArtField* Class::FindDeclaredField(ObjPtr<DexCache> dex_cache, uint32_t dex_field_idx) { - if (dex_cache == GetDexCache()) { - for (ArtField& field : GetFields()) { - if (field.GetDexFieldIndex() == dex_field_idx) { - return &field; + size_t num_fields = NumFields(); + if (dex_cache == GetDexCache() && num_fields > 0) { + // The field array is an ordered list of fields where there may be missing + // indices. For example, it could be [40, 42], but in 90% of cases cases we have + // [40, 41, 42]. The latter is the case we are optimizing for, where for + // example `dex_field_idx` is 41, and we can just substract it with the + // first field index (40) and directly access the array with that index (1). + uint32_t index = dex_field_idx - GetField(0)->GetDexFieldIndex(); + if (index < num_fields) { + ArtField* field = GetField(index); + if (field->GetDexFieldIndex() == dex_field_idx) { + return field; + } + } else { + index = num_fields; + } + // If there is a field, it's down the array. The array is ordered by field + // index, so we know we can stop the search if `dex_field_idx` is greater + // than the current field's index. + for (; index > 0; --index) { + ArtField* field = GetField(index - 1); + if (field->GetDexFieldIndex() == dex_field_idx) { + return field; + } else if (field->GetDexFieldIndex() < dex_field_idx) { + break; } } } |