[C++][SIMD] Avoid one-definition-rule violation of `arrow::internal::BitmapWriter` without depending on `-O2`
- 主要言語
- C++
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- マージ済み PR(30日)
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説明
### Describe the enhancement requested
Contexts:
* https://github.com/apache/arrow/issues/31132#issuecomment-1378082076
* GH-14342
* GH-36685
We have runtime SIMD dispatch feature. For example, it's used in `cpp/src/parquet/level_conversion.cc` to run BMI2 based `DefLevelsToBitmap` implementation if available.
`DefLevelsToBitmap` (`DefLevelsToBitmapSimd`) is implemented in `cpp/src/parquet/level_conversion_inc.h` and it's built with/without BMI2. `DefLevelsToBitmapSimd` uses `arrow::internal::BitmapWriter`. If `arrow::internal::BitmapWriter` in `DefLevelsToBitmapSimd` is not inlined, one-definition-rule violation is happen. If it's happen, `libparquet.dylib` has two `BitmapWriter` definitions for with/without BMI2. If BMI2 version `BitmapWriter` is used on BMI2 unavailable machine, "illegal opcode" is happen.
GH-14342 resolved this by forcing to use `-O2` to enforce inlining. But it doesn't work with Homebrew. Because Homebrew overrides `-O*` specified by us.
If we can avoid one-definition-rule violation of `arrow::internal::BitmapWriter` without depending on `-O2`, we can provide a Homebrew bottle that can use the BMI2 based implementation on machines that support BMI2.
### Component(s)
C++
コントリビューションガイド
調査の方向性
Start with cpp/src/parquet/level_conversion.cc and cpp/src/parquet/level_conversion_inc.h, focusing on DefLevelsToBitmap, DefLevelsToBitmapSimd, and their use of arrow::internal::BitmapWriter. Check how the BMI2 and non-BMI2 variants are built and dispatched. Done means avoiding duplicate BitmapWriter definitions and illegal opcodes without depending on -O2, including for Homebrew builds.
索引モデルが issue の本文から書いたものです。
評価
- 技術スタック
- cpp
- 領域
- build-system, performance
- issue の種類
- バグ
- 難易度
- 4/5
- 見積もり時間
- 3〜5日
- 活発さ
- 停滞
- 明瞭さ
- おおむね明確
- 初心者へのやさしさ
- 35/100