使用 Clang 编译时，链接器无法在 64 位 Mint OS 下找到 32 位库

Question

我刚刚在 64 位 Mint OS（版本 17）上安装了 Clang 3.5。我正在尝试以 32 位编译我的程序，但是我遇到了问题。

我的主目录中有一个名为 test.cpp 的文件，代码如下：

#include <iostream>

int main()
{
    std::cout << "Hello" << std::endl;
}

然后我运行以下命令：

$ clang++ -m32 -Wl,--verbose test.cpp | grep libgcc

我得到以下输出：

$ clang++ -m32 -Wl,--verbose test.cpp | grep libgcc
/usr/bin/ld: skipping incompatible /usr/bin/../lib/gcc/x86_64-linux-gnu/4.8/libstdc++.so when searching for -lstdc++
/usr/bin/ld: skipping incompatible /usr/bin/../lib/gcc/x86_64-linux-gnu/4.8/libstdc++.a when searching for -lstdc++
/usr/bin/ld: cannot find -lstdc++
/usr/bin/ld: skipping incompatible /usr/bin/../lib/gcc/x86_64-linux-gnu/4.8/libgcc_s.so when searching for -lgcc_s
attempt to open /usr/bin/../lib/gcc/x86_64-linux-gnu/4.8/libgcc_s.so succeeded
/usr/bin/ld: cannot find -lgcc_s
attempt to open /usr/bin/../lib/gcc/x86_64-linux-gnu/4.8/libgcc_s.a failed
attempt to open /usr/bin/../lib/gcc/x86_64-linux-gnu/4.8/../../../i386-linux-gnu/libgcc_s.so failed
/usr/bin/ld: skipping incompatible /usr/bin/../lib/gcc/x86_64-linux-gnu/4.8/libgcc.a when searching for -lgcc
attempt to open /usr/bin/../lib/gcc/x86_64-linux-gnu/4.8/../../../i386-linux-gnu/libgcc_s.a failed
attempt to open /usr/bin/../lib/gcc/x86_64-linux-gnu/4.8/../../../../lib32/libgcc_s.so failed
attempt to open /usr/bin/../lib/gcc/x86_64-linux-gnu/4.8/../../../../lib32/libgcc_s.a failed
attempt to open /usr/bin/../lib/i386-linux-gnu/libgcc_s.so failed
/usr/bin/ld: cannot find -lgcc
attempt to open /usr/bin/../lib/i386-linux-gnu/libgcc_s.a failed
attempt to open /usr/bin/../lib32/libgcc_s.so failed
attempt to open /usr/bin/../lib32/libgcc_s.a failed
attempt to open /lib/i386-linux-gnu/libgcc_s.so failed
attempt to open /lib/i386-linux-gnu/libgcc_s.a failed
attempt to open /lib/../lib32/libgcc_s.so failed
attempt to open /lib/../lib32/libgcc_s.a failed
attempt to open /usr/lib/i386-linux-gnu/libgcc_s.so failed
attempt to open /usr/lib/i386-linux-gnu/libgcc_s.a failed
attempt to open /usr/lib/../lib32/libgcc_s.so failed
attempt to open /usr/lib/../lib32/libgcc_s.a failed
attempt to open /usr/lib/x86_64-linux-gnu/../../lib32/libgcc_s.so failed
attempt to open /usr/lib/x86_64-linux-gnu/../../lib32/libgcc_s.a failed
attempt to open /usr/bin/../lib/gcc/x86_64-linux-gnu/4.8/../../../libgcc_s.so failed
attempt to open /usr/bin/../lib/gcc/x86_64-linux-gnu/4.8/../../../libgcc_s.a failed
attempt to open /usr/bin/../lib/libgcc_s.so failed
attempt to open /usr/bin/../lib/libgcc_s.a failed
attempt to open /lib/libgcc_s.so failed
attempt to open /lib/libgcc_s.a failed
attempt to open /usr/lib/libgcc_s.so failed
attempt to open /usr/lib/libgcc_s.a failed
attempt to open /usr/i386-linux-gnu/lib32/libgcc_s.so failed
attempt to open /usr/i386-linux-gnu/lib32/libgcc_s.a failed
attempt to open /usr/x86_64-linux-gnu/lib32/libgcc_s.so failed
attempt to open /usr/x86_64-linux-gnu/lib32/libgcc_s.a failed
attempt to open //usr/local/lib/i386-linux-gnu/libgcc_s.so failed
attempt to open //usr/local/lib/i386-linux-gnu/libgcc_s.a failed
attempt to open //usr/local/lib32/libgcc_s.so failed
attempt to open //usr/local/lib32/libgcc_s.a failed
attempt to open //lib/i386-linux-gnu/libgcc_s.so failed
attempt to open //lib/i386-linux-gnu/libgcc_s.a failed
attempt to open //lib32/libgcc_s.so failed
attempt to open //lib32/libgcc_s.a failed
attempt to open //usr/lib/i386-linux-gnu/libgcc_s.so failed
attempt to open //usr/lib/i386-linux-gnu/libgcc_s.a failed
attempt to open //usr/lib32/libgcc_s.so failed
attempt to open //usr/lib32/libgcc_s.a failed
attempt to open //usr/local/lib/libgcc_s.so failed
attempt to open //usr/local/lib/libgcc_s.a failed
attempt to open //lib/libgcc_s.so failed
attempt to open //lib/libgcc_s.a failed
attempt to open //usr/lib/libgcc_s.so failed
attempt to open //usr/lib/libgcc_s.a failed
attempt to open /usr/bin/../lib/gcc/x86_64-linux-gnu/4.8/libgcc.so failed
attempt to open /usr/bin/../lib/gcc/x86_64-linux-gnu/4.8/libgcc.a succeeded
attempt to open /usr/bin/../lib/gcc/x86_64-linux-gnu/4.8/../../../i386-linux-gnu/libgcc.so failed
attempt to open /usr/bin/../lib/gcc/x86_64-linux-gnu/4.8/../../../i386-linux-gnu/libgcc.a failed
attempt to open /usr/bin/../lib/gcc/x86_64-linux-gnu/4.8/../../../../lib32/libgcc.so failed
attempt to open /usr/bin/../lib/gcc/x86_64-linux-gnu/4.8/../../../../lib32/libgcc.a failed
attempt to open /usr/bin/../lib/i386-linux-gnu/libgcc.so failed
attempt to open /usr/bin/../lib/i386-linux-gnu/libgcc.a failed
attempt to open /usr/bin/../lib32/libgcc.so failed
attempt to open /usr/bin/../lib32/libgcc.a failed
attempt to open /lib/i386-linux-gnu/libgcc.so failed
attempt to open /lib/i386-linux-gnu/libgcc.a failed
attempt to open /lib/../lib32/libgcc.so failed
attempt to open /lib/../lib32/libgcc.a failed
attempt to open /usr/lib/i386-linux-gnu/libgcc.so failed
attempt to open /usr/lib/i386-linux-gnu/libgcc.a failed
attempt to open /usr/lib/../lib32/libgcc.so failed
attempt to open /usr/lib/../lib32/libgcc.a failed
attempt to open /usr/lib/x86_64-linux-gnu/../../lib32/libgcc.so failed
attempt to open /usr/lib/x86_64-linux-gnu/../../lib32/libgcc.a failed
attempt to open /usr/bin/../lib/gcc/x86_64-linux-gnu/4.8/../../../libgcc.so failed
attempt to open /usr/bin/../lib/gcc/x86_64-linux-gnu/4.8/../../../libgcc.a failed
attempt to open /usr/bin/../lib/libgcc.so failed
attempt to open /usr/bin/../lib/libgcc.a failed
attempt to open /lib/libgcc.so failed
attempt to open /lib/libgcc.a failed
attempt to open /usr/lib/libgcc.so failed
attempt to open /usr/lib/libgcc.a failed
attempt to open /usr/i386-linux-gnu/lib32/libgcc.so failed
attempt to open /usr/i386-linux-gnu/lib32/libgcc.a failed
attempt to open /usr/x86_64-linux-gnu/lib32/libgcc.so failed
attempt to open /usr/x86_64-linux-gnu/lib32/libgcc.a failed
attempt to open //usr/local/lib/i386-linux-gnu/libgcc.so failed
attempt to open //usr/local/lib/i386-linux-gnu/libgcc.a failed
attempt to open //usr/local/lib32/libgcc.so failed
attempt to open //usr/local/lib32/libgcc.a failed
attempt to open //lib/i386-linux-gnu/libgcc.so failed
attempt to open //lib/i386-linux-gnu/libgcc.a failed
attempt to open //lib32/libgcc.so failed
attempt to open //lib32/libgcc.a failed
attempt to open //usr/lib/i386-linux-gnu/libgcc.so failed
attempt to open //usr/lib/i386-linux-gnu/libgcc.a failed
attempt to open //usr/lib32/libgcc.so failed
attempt to open //usr/lib32/libgcc.a failed
attempt to open //usr/local/lib/libgcc.so failed
attempt to open //usr/local/lib/libgcc.a failed
attempt to open //lib/libgcc.so failed
attempt to open //lib/libgcc.a failed
attempt to open //usr/lib/libgcc.so failed
attempt to open //usr/lib/libgcc.a failed
clang: error: linker command failed with exit code 1 (use -v to see invocation)

我已经尽我所能进行了所有的谷歌搜索和自我调查，我不确定为什么这个简单的例子不起作用。谁能帮我弄清楚我错过了什么？

Answer 1

以下是使用 clang 进行交叉编译时要确保的内容：

• 您是否安装了 32 位 (x86) C++ 库？ （看起来你有，但只是确保。）

• 尝试使用--sysroot=<location of your 32-bit multilibs>。这将告诉 clang 在您告诉它的特定目录中搜​​索 bin、lib 和 include 目录，而不是使用其（定义不明确的）硬编码路径。

• 尝试使用-I 和-L 选项更具体地告诉clang 你的include 和lib 目录在哪里。

• 如果以上都不起作用，则最坏的情况是：尝试使用 -B <path> 选项告诉 clang 要具体使用哪个链接器。尝试将其与之前的选项结合使用。

请参阅http://clang.llvm.org/docs/CrossCompilation.html 了解更多详情（尽管此处未涵盖-B 选项）

Answer 2

你需要安装一个multilib g++ sudo apt-get install g++-multilib。

g++-multilib 还应该安装所有其他必需的依赖项，例如libc6-i386。

Answer 3

在 64 位机器（例如 AMD64）上，您必须安装 32 位库等。例如，在 Debian 10 (Buster) 上，这是：

sudo apt install libc6-i386 lib32gcc1 lib32gcc-8-dev gcc-8-multilib

在 Debian 11 (Bullseye) 上，这是：

sudo apt install libc6-i386 lib32gcc-10-dev gcc-10-multilib

（对于 C++，分别添加 g++-8-multilib 或 g++-10-multilib）

完成这些安装后，您将在 /lib32 和 /usr/lib32 中获得新的 32 位库。此外，在 /etc/ld.so.conf.d 中你会发现新的配置（/sbin/ldconfig 由 apt 安装自动执行）。

在 Debian Buster 上，我可以使用 gcc 和 -m32 开关 (gcc-8.3.0) 轻松编译。在 Debian Bullseye (gcc-10.2.0) 上，仅使用 -m32 的 gcc 让我很难受。

在 Bullseye 上正确执行 32 位可执行文件的 gcc：

gcc -m32 -Wl,--rpath-link,/usr/lib32 -L/usr/lib32 -nodefaultlibs -nostdlib -o /usr/lib32/crti.o /usr/lib32/crt1.o /usr/ lib32/crtn.o -lc -lgcc_s