Move Semantics Assembly Surprise

#include <string> inline void bin(std::string& val) { val.append("Hello C++ Russia!"); } void goo(std::string& s) { bin(s); bin(s); bin(s); bin(s); bin(s); } string "Hello C++ Russia!" goo(std::__cxx11::basic_string<char, std::char_traits<char>... push rbp mov esi, OFFSET FLAT:.LC0 mov rbp, rdi call std::__cxx11::basic_string<char, std::... mov rdi, rbp mov esi, OFFSET FLAT:.LC0 call std::__cxx11::basic_string<char, std::... mov rdi, rbp mov esi, OFFSET FLAT:.LC0 call std::__cxx11::basic_string<char, std::... mov rdi, rbp mov esi, OFFSET FLAT:.LC0 call std::__cxx11::basic_string<char, std::... mov rdi, rbp jmp std::__cxx11::basic_string<char, std::...

A split-screen screenshot shows simple C++ code repeatedly appending “Hello C++ Russia!” to a string on the left, alongside the generated x86-64 assembly on the right. The joke is that a tiny high-level function expands into intimidating compiler output, making optimization and move-semantics discussions look unnecessarily complex. EN: A split-screen screenshot shows simple C++ code repeatedly appending “Hello C++ Russia!” to a string on the left, alongside the generated x86-64 assembly on the right. The joke is that a tiny high-level function expands into intimidating compiler output, making optimization and move-semantics discussions look unnecessarily complex.

• @ithueti / 847 2019-04-19