与GCC构建的静态库链接时，MSVC项目缺少“ __popcountdi2”
[英]MSVC project missing “__popcountdi2” when linking against GCC-built static library
问题描述
I have a windows executable project that links against a static library (.lib) built with GCC 6 (MinGW). 
我有一个Windows可执行项目，该项目链接到使用GCC 6（MinGW）构建的静态库（.lib）。 The following error occurs during compilation: 编译期间发生以下错误：
LNK2019 unresolved external symbol __popcountdi2 referenced in function ...
The symbol is linked in as a result of using a GCC built-in function __builtin_popcount() , which resides in libgcc. 通过使用驻留在libgcc中的GCC内置函数__builtin_popcount()来链接该符号。 However, despite adding -static-libgcc as an argument to gcc, the problem still persists. 但是，尽管将-static-libgcc添加为gcc的参数，但问题仍然存在。
Is there a way for my library (.lib) to contain parts of libgcc rather than requiring libgcc to be on the system for an executable to link against? 有没有一种方法可以让我的库（.lib）包含libgcc的某些部分，而不是要求libgcc位于系统上以链接可执行文件？ Is some way around having to ship the library with libgcc? 是否需要通过libgcc来运送库？
__builtin_popcount() is not the only built-in function that I'm currently using. __builtin_popcount()不是我当前正在使用的唯一内置函数。 The library makes use of __builtin_bswap32() , which doesn't seem to run into this issue. 该库使用了__builtin_bswap32() ，似乎没有遇到这个问题。
I'm using GCC 6.1.0. 我正在使用GCC 6.1.0。 Updated to 6.2.0; 更新到6.2.0; same issue. 同样的问题。
1 个解决方案
解决方案1
0 已采纳 2016-11-01 13:19:45
The issue was that on windows, MinGW (GCC) was not detecting the current CPU architecture properly when -march=native was passed in. It was falling back to an architecture that did not support POPCNT as a native instruction (probably i686). 问题是在Windows上，当传入-march=native时，MinGW（GCC）无法正确检测当前的CPU体系结构。它回退到了不支持POPCNT作为本机指令的体系结构（可能是i686）。 As a test, -mpopcnt was added to the build and everything worked fine. 作为测试， -mpopcnt被添加到构建中，并且一切正常。
The fix is to manually specify the architecture using -march= . 解决方法是使用-march=手动指定体系结构。
Furthermore: is this a bug with MingGW since the native architecture is not polled for properly? 此外：由于未正确轮询本机体系结构，这是否是MingGW的错误？
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