Windows 中的 Clang++ 4.0.0 编译错误答案

【问题标题】：Clang++ 4.0.0 compilation error in windowsWindows 中的 Clang++ 4.0.0 编译错误
【发布时间】：2018-03-24 22:09:55
【问题描述】：

我在 Windows 10（32 位操作系统，x86 处理器）上使用从源代码编译的 clang 4.0.0。我正在尝试将我的 cpp 代码编译为 ll 格式的 llvm ir 代码。这是一个使用 clang 编译失败的示例代码：

#include <windows.h>
#include <tlhelp32.h>
#include <fstream>
#include <mapi.h>
#include <memory>
#include<stdio.h>

/* Function to calculate x raised to the power y */
int power(int x, unsigned int y)
{
    if (y == 0)
        return 1;
    else if (y%2 == 0)
        return power(x, y/2)*power(x, y/2);
    else
        return x*power(x, y/2)*power(x, y/2);
}

/* Program to test function power */
int main()
{
    int x = 2;
    unsigned int y = 3;

    printf("%d", power(x, y));
    return 0;
}

这只是一个示例代码，但在包括列出的头文件的所有 c++ 代码中它的行为都是相同的。我使用以下命令将其编译为 llvm ir 代码：

clang++ -S -emit-llvm assiral.cpp -o assiral.ll

编译时出现以下错误：

C:\Sample>clang++ -emit-llvm -S assiral.cpp -o assiral.ll
In file included from assiral.cpp:3:
In file included from C:\Program Files\Microsoft Visual Studio\2017\Enterprise\VC\Tools\MSVC\14.11.25503\include\fstream:6:
In file included from C:\Program Files\Microsoft Visual Studio\2017\Enterprise\VC\Tools\MSVC\14.11.25503\includem:6:
In file included from C:\Program Files\Microsoft Visual Studio\2017\Enterprise\VC\Tools\MSVC\14.11.25503\include\ostream:6:
In file included from C:\Program Files\Microsoft Visual Studio\2017\Enterprise\VC\Tools\MSVC\14.11.25503\include\ios:6:
In file included from C:\Program Files\Microsoft Visual Studio\2017\Enterprise\VC\Tools\MSVC\14.11.25503\include\xlocnum:7:
In file included from C:\Program Files\Microsoft Visual Studio\2017\Enterprise\VC\Tools\MSVC\14.11.25503\include\cmath:617:
In file included from C:\Program Files\Microsoft Visual Studio\2017\Enterprise\VC\Tools\MSVC\14.11.25503\include\xtgmath.h:9:
C:\Program Files\Microsoft Visual Studio\2017\Enterprise\VC\Tools\MSVC\14.11.25503\include\xtr1common:204:22: error:
use of undeclared identifier 'char16_t'
struct _Is_integral<char16_t>
^
C:\Program Files\Microsoft Visual Studio\2017\Enterprise\VC\Tools\MSVC\14.11.25503\include\xtr1common:210:22: error:
use of undeclared identifier 'char32_t'
struct _Is_integral<char32_t>
^
In file included from assiral.cpp:3:
In file included from C:\Program Files\Microsoft Visual Studio\2017\Enterprise\VC\Tools\MSVC\14.11.25503\include\fstream:6:
In file included from C:\Program Files\Microsoft Visual Studio\2017\Enterprise\VC\Tools\MSVC\14.11.25503\includem:6:
In file included from C:\Program Files\Microsoft Visual Studio\2017\Enterprise\VC\Tools\MSVC\14.11.25503\include\ostream:6:
In file included from C:\Program Files\Microsoft Visual Studio\2017\Enterprise\VC\Tools\MSVC\14.11.25503\include\ios:6:
In file included from C:\Program Files\Microsoft Visual Studio\2017\Enterprise\VC\Tools\MSVC\14.11.25503\include\xlocnum:10:
In file included from C:\Program Files\Microsoft Visual Studio\2017\Enterprise\VC\Tools\MSVC\14.11.25503\include\streambuf:6:
In file included from C:\Program Files\Microsoft Visual Studio\2017\Enterprise\VC\Tools\MSVC\14.11.25503\include\xiosbase:6:
In file included from C:\Program Files\Microsoft Visual Studio\2017\Enterprise\VC\Tools\MSVC\14.11.25503\include\xlocale:8:
In file included from C:\Program Files\Microsoft Visual Studio\2017\Enterprise\VC\Tools\MSVC\14.11.25503\include\stdexcept:6:
In file included from C:\Program Files\Microsoft Visual Studio\2017\Enterprise\VC\Tools\MSVC\14.11.25503\include\exception:7:
In file included from C:\Program Files\Microsoft Visual Studio\2017\Enterprise\VC\Tools\MSVC\14.11.25503\include\type_traits:6:
C:\Program Files\Microsoft Visual Studio\2017\Enterprise\VC\Tools\MSVC\14.11.25503\include\xstddef:257:2: error: 'auto'
  return without trailing return type; deduced return types are a C++14 extension
auto _Unfancy(_Ptrty _Ptr)
  ^
  In file included from assiral.cpp:3:
  In file included from C:\Program Files\Microsoft Visual Studio\2017\Enterprise\VC\Tools\MSVC\14.11.25503\include\fstream:6:
  In file included from C:\Program Files\Microsoft Visual Studio\2017\Enterprise\VC\Tools\MSVC\14.11.25503\includem:6:
  In file included from C:\Program Files\Microsoft Visual Studio\2017\Enterprise\VC\Tools\MSVC\14.11.25503\include\ostream:6:
  In file included from C:\Program Files\Microsoft Visual Studio\2017\Enterprise\VC\Tools\MSVC\14.11.25503\include\ios:6:
  In file included from C:\Program Files\Microsoft Visual Studio\2017\Enterprise\VC\Tools\MSVC\14.11.25503\include\xlocnum:10:
  In file included from C:\Program Files\Microsoft Visual Studio\2017\Enterprise\VC\Tools\MSVC\14.11.25503\include\streambuf:6:
  In file included from C:\Program Files\Microsoft Visual Studio\2017\Enterprise\VC\Tools\MSVC\14.11.25503\include\xiosbase:6:
  In file included from C:\Program Files\Microsoft Visual Studio\2017\Enterprise\VC\Tools\MSVC\14.11.25503\include\xlocale:8:
  In file included from C:\Program Files\Microsoft Visual Studio\2017\Enterprise\VC\Tools\MSVC\14.11.25503\include\stdexcept:7:
  In file included from C:\Program Files\Microsoft Visual Studio\2017\Enterprise\VC\Tools\MSVC\14.11.25503\include\xstring:6:
  In file included from C:\Program Files\Microsoft Visual Studio\2017\Enterprise\VC\Tools\MSVC\14.11.25503\include\xmemory0:8:
  C:\Program Files\Microsoft Visual Studio\2017\Enterprise\VC\Tools\MSVC\14.11.25503\include\limits:612:33: error: use of
  undeclared identifier 'char16_t'
  template<> class numeric_limits<char16_t>
  ^
  C:\Program Files\Microsoft Visual Studio\2017\Enterprise\VC\Tools\MSVC\14.11.25503\include\limits:902:33: error: use of
  undeclared identifier 'char32_t'
  template<> class numeric_limits<char32_t>
  ^
  In file included from assiral.cpp:3:
  In file included from C:\Program Files\Microsoft Visual Studio\2017\Enterprise\VC\Tools\MSVC\14.11.25503\include\fstream:6:
  In file included from C:\Program Files\Microsoft Visual Studio\2017\Enterprise\VC\Tools\MSVC\14.11.25503\includem:6:
  In file included from C:\Program Files\Microsoft Visual Studio\2017\Enterprise\VC\Tools\MSVC\14.11.25503\include\ostream:6:
  In file included from C:\Program Files\Microsoft Visual Studio\2017\Enterprise\VC\Tools\MSVC\14.11.25503\include\ios:6:
  In file included from C:\Program Files\Microsoft Visual Studio\2017\Enterprise\VC\Tools\MSVC\14.11.25503\include\xlocnum:10:
  In file included from C:\Program Files\Microsoft Visual Studio\2017\Enterprise\VC\Tools\MSVC\14.11.25503\include\streambuf:6:
  In file included from C:\Program Files\Microsoft Visual Studio\2017\Enterprise\VC\Tools\MSVC\14.11.25503\include\xiosbase:6:
  In file included from C:\Program Files\Microsoft Visual Studio\2017\Enterprise\VC\Tools\MSVC\14.11.25503\include\xlocale:8:
  In file included from C:\Program Files\Microsoft Visual Studio\2017\Enterprise\VC\Tools\MSVC\14.11.25503\include\stdexcept:7:
  In file included from C:\Program Files\Microsoft Visual Studio\2017\Enterprise\VC\Tools\MSVC\14.11.25503\include\xstring:6:
  In file included from C:\Program Files\Microsoft Visual Studio\2017\Enterprise\VC\Tools\MSVC\14.11.25503\include\xmemory0:10:
  In file included from C:\Program Files\Microsoft Visual Studio\2017\Enterprise\VC\Tools\MSVC\14.11.25503\include\xutility:8:
  In file included from C:\Program Files\Microsoft Visual Studio\2017\Enterprise\VC\Tools\MSVC\14.11.25503\include\utility:7:
  C:\Program Files\Microsoft Visual Studio\2017\Enterprise\VC\Tools\MSVC\14.11.25503\include\iosfwd:254:21: error: use of
  undeclared identifier 'char16_t'
  struct char_traits<char16_t>
  ^
  C:\Program Files\Microsoft Visual Studio\2017\Enterprise\VC\Tools\MSVC\14.11.25503\include\iosfwd:263:21: error: use of
  undeclared identifier 'char32_t'
  struct char_traits<char32_t>
  ^
  In file included from assiral.cpp:3:
  In file included from C:\Program Files\Microsoft Visual Studio\2017\Enterprise\VC\Tools\MSVC\14.11.25503\include\fstream:6:
  In file included from C:\Program Files\Microsoft Visual Studio\2017\Enterprise\VC\Tools\MSVC\14.11.25503\includem:6:
  In file included from C:\Program Files\Microsoft Visual Studio\2017\Enterprise\VC\Tools\MSVC\14.11.25503\include\ostream:6:
  In file included from C:\Program Files\Microsoft Visual Studio\2017\Enterprise\VC\Tools\MSVC\14.11.25503\include\ios:6:
  In file included from C:\Program Files\Microsoft Visual Studio\2017\Enterprise\VC\Tools\MSVC\14.11.25503\include\xlocnum:10:
  In file included from C:\Program Files\Microsoft Visual Studio\2017\Enterprise\VC\Tools\MSVC\14.11.25503\include\streambuf:6:
  In file included from C:\Program Files\Microsoft Visual Studio\2017\Enterprise\VC\Tools\MSVC\14.11.25503\include\xiosbase:6:
  In file included from C:\Program Files\Microsoft Visual Studio\2017\Enterprise\VC\Tools\MSVC\14.11.25503\include\xlocale:8:
  In file included from C:\Program Files\Microsoft Visual Studio\2017\Enterprise\VC\Tools\MSVC\14.11.25503\include\stdexcept:7:
  In file included from C:\Program Files\Microsoft Visual Studio\2017\Enterprise\VC\Tools\MSVC\14.11.25503\include\xstring:6:
  In file included from C:\Program Files\Microsoft Visual Studio\2017\Enterprise\VC\Tools\MSVC\14.11.25503\include\xmemory0:10:
  C:\Program Files\Microsoft Visual Studio\2017\Enterprise\VC\Tools\MSVC\14.11.25503\include\xutility:698:2: error:
  'auto' return without trailing return type; deduced return types are a C++14 extension
auto _Unchecked_n(_Iter _Src, _Diff)
  ^
  C:\Program Files\Microsoft Visual Studio\2017\Enterprise\VC\Tools\MSVC\14.11.25503\include\xutility:742:2: error:
  'auto' return without trailing return type; deduced return types are a C++14 extension
auto _Unchecked_n_backward(_Iter _Src, _Diff)
  ^
  C:\Program Files\Microsoft Visual Studio\2017\Enterprise\VC\Tools\MSVC\14.11.25503\include\xutility:1142:12: error:
  deduced return types are a C++14 extension
constexpr decltype(auto) _Operator_arrow(_Iterator&& _Target, false_type)
  ^
  In file included from assiral.cpp:3:
  In file included from C:\Program Files\Microsoft Visual Studio\2017\Enterprise\VC\Tools\MSVC\14.11.25503\include\fstream:6:
  In file included from C:\Program Files\Microsoft Visual Studio\2017\Enterprise\VC\Tools\MSVC\14.11.25503\includem:6:
  In file included from C:\Program Files\Microsoft Visual Studio\2017\Enterprise\VC\Tools\MSVC\14.11.25503\include\ostream:6:
  In file included from C:\Program Files\Microsoft Visual Studio\2017\Enterprise\VC\Tools\MSVC\14.11.25503\include\ios:6:
  In file included from C:\Program Files\Microsoft Visual Studio\2017\Enterprise\VC\Tools\MSVC\14.11.25503\include\xlocnum:10:
  In file included from C:\Program Files\Microsoft Visual Studio\2017\Enterprise\VC\Tools\MSVC\14.11.25503\include\streambuf:6:
  In file included from C:\Program Files\Microsoft Visual Studio\2017\Enterprise\VC\Tools\MSVC\14.11.25503\include\xiosbase:6:
  In file included from C:\Program Files\Microsoft Visual Studio\2017\Enterprise\VC\Tools\MSVC\14.11.25503\include\xlocale:8:
  In file included from C:\Program Files\Microsoft Visual Studio\2017\Enterprise\VC\Tools\MSVC\14.11.25503\include\stdexcept:7:
  In file included from C:\Program Files\Microsoft Visual Studio\2017\Enterprise\VC\Tools\MSVC\14.11.25503\include\xstring:6:
  C:\Program Files\Microsoft Visual Studio\2017\Enterprise\VC\Tools\MSVC\14.11.25503\include\xmemory0:356:2: error:
  'auto' return without trailing return type; deduced return types are a C++14 extension
auto _Const_cast(_Ptrty _Ptr)
  ^
  C:\Program Files\Microsoft Visual Studio\2017\Enterprise\VC\Tools\MSVC\14.11.25503\include\xmemory0:366:2: error:
  'auto' return without trailing return type; deduced return types are a C++14 extension
auto _Const_cast(_Ty * _Ptr)
  ^
  In file included from assiral.cpp:3:
  In file included from C:\Program Files\Microsoft Visual Studio\2017\Enterprise\VC\Tools\MSVC\14.11.25503\include\fstream:6:
  In file included from C:\Program Files\Microsoft Visual Studio\2017\Enterprise\VC\Tools\MSVC\14.11.25503\includem:6:
  In file included from C:\Program Files\Microsoft Visual Studio\2017\Enterprise\VC\Tools\MSVC\14.11.25503\include\ostream:6:
  In file included from C:\Program Files\Microsoft Visual Studio\2017\Enterprise\VC\Tools\MSVC\14.11.25503\include\ios:6:
  In file included from C:\Program Files\Microsoft Visual Studio\2017\Enterprise\VC\Tools\MSVC\14.11.25503\include\xlocnum:10:
  In file included from C:\Program Files\Microsoft Visual Studio\2017\Enterprise\VC\Tools\MSVC\14.11.25503\include\streambuf:6:
  In file included from C:\Program Files\Microsoft Visual Studio\2017\Enterprise\VC\Tools\MSVC\14.11.25503\include\xiosbase:6:
  In file included from C:\Program Files\Microsoft Visual Studio\2017\Enterprise\VC\Tools\MSVC\14.11.25503\include\xlocale:8:
  In file included from C:\Program Files\Microsoft Visual Studio\2017\Enterprise\VC\Tools\MSVC\14.11.25503\include\stdexcept:7:
  C:\Program Files\Microsoft Visual Studio\2017\Enterprise\VC\Tools\MSVC\14.11.25503\include\xstring:75:2: error:
  statement not allowed in constexpr function
  for (auto _Match_try = _Haystack + _Start_at; ; ++_Match_try)
  ^
  C:\Program Files\Microsoft Visual Studio\2017\Enterprise\VC\Tools\MSVC\14.11.25503\include\xstring:119:3: error:
  statement not allowed in constexpr function
  for (auto _Match_try = _Haystack + _Min_value(_Start_at, _Hay_size - _Needle_size); ; --_Match_try)
  ^
  C:\Program Files\Microsoft Visual Studio\2017\Enterprise\VC\Tools\MSVC\14.11.25503\include\xstring:144:3: error:
  statement not allowed in constexpr function
  for (auto _Match_try = _Haystack + _Min_value(_Start_at, _Hay_size - 1); ; --_Match_try)
  ^
  C:\Program Files\Microsoft Visual Studio\2017\Enterprise\VC\Tools\MSVC\14.11.25503\include\xstring:169:3: error:
  statement not allowed in constexpr function
  for (auto _Match_try = _Haystack + _Start_at; _Match_try < _End; ++_Match_try)
  ^
  C:\Program Files\Microsoft Visual Studio\2017\Enterprise\VC\Tools\MSVC\14.11.25503\include\xstring:188:3: error:
  statement not allowed in constexpr function
  for (auto _Match_try = _Haystack + _Min_value(_Start_at, _Hay_size - 1); ; --_Match_try)
  ^
  C:\Program Files\Microsoft Visual Studio\2017\Enterprise\VC\Tools\MSVC\14.11.25503\include\xstring:213:3: error:
  statement not allowed in constexpr function
  for (auto _Match_try = _Haystack + _Start_at; _Match_try < _End; ++_Match_try)
  ^
  C:\Program Files\Microsoft Visual Studio\2017\Enterprise\VC\Tools\MSVC\14.11.25503\include\xstring:233:3: error:
  statement not allowed in constexpr function
  for (auto _Match_try = _Haystack + _Start_at; _Match_try < _End; ++_Match_try)
  ^
  fatal error: too many errors emitted, stopping now [-ferror-limit=]
  20 errors generated.

运行命令后我期望生成字节码文件（.ll 文件）。我看过很多帖子，他们在命令中引入了一个标志：'-fms-compatibility-version=19'。但是，添加的标志被标记为未知参数。我正在使用 MSVS 2017。也许我用错了这个标志。但我已经陷入僵局一天了。任何帮助或建议将不胜感激。

【问题讨论】：

请包含一个最小的可编译示例。
感谢您更新您的问题。通过稍微修改的源代码来删除 Windows 特定的头文件，它在 Linux 下编译得很好。所以这就是我开始故障排除的地方。尝试重新排列您的包含并删除不需要的。
你到底是什么意思？由于头文件问题，它没有进入编译阶段。
我正在处理您的最小示例，它不需要标题 windows.h、tlhelp32.h 或 mapi.h。它也不需要fstream 或memory，但无论如何我已经用这些标题验证了你的最小示例（因为它们是标准的。）
感谢您的即时回复。标头是我要编译的实际代码的一部分。正如我之前提到的：“这只是一个示例代码，但在包括列出的头文件的所有 c++ 代码中它的行为都是相同的。”我有一个使用这些头文件的源代码，需要在 Windows 中编译。我很清楚这个问题与特定于 Windows 的头文件有关：) 故障排除是我请求帮助的地方。重新排列包括对我没有多大作用:(

标签： c++ windows clang visual-studio-2017 llvm-clang

【解决方案1】：

已通过在环境变量 INCLUDE 中添加头文件的正确路径来解决此问题。修复路径后，我的大部分错误都得到了解决。这包括编译引用某些头文件（如 windows.h）的 c++ 文件会导致找不到文件的错误。

如何做同样的事情的链接：List all environment variables from command line?

您还可以解决另一个问题：

link fatal error lnk1104 cannot open file 'libcmt.lib'

通过将 LIBPATH 环境变量设置为指向 libcmt.lib 文件的正确位置。我在以下位置找到了我的：

C:\Program Files\Microsoft Visual Studio 14.0\VC\lib

这些琐碎的问题让我花了好几天才弄清楚。希望这可以为别人省去同样的麻烦。

【讨论】：