Parsing Protobuf at 2+GB/s: How I Learned To Love Tail Calls in C

An exciting feature just landed in the main branch of the Clang compiler. Using the [[clang::musttail]] or __attribute__((musttail)) statement attributes, you can now get guaranteed tail calls in C, C++, and Objective-C. While tail calls are usually associated with a functional programming style, I am interested in them purely for performance reasons. It turns out that in some cases we can use tai

[p_tan]

末尾再帰最適化の手動制御でprotocol buffersのパースを二倍高速化した話。clangの独自属性を使用。

[mattn]

__attribute__((musttail)) を付けると jmp 命令だけに出来るらしい。(自分で末尾最適化が可能と判断できるなら)