I'm using clang 4.0.0 compiled from source on windows 10 (32-bit OS, x86 processor). I'm trying to compile my cpp code to llvm ir code of the format ll. Here's a sample code which fails to compile using clang:
#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;
}
This is just a sample code, but it's the same behavior across all c++ code which include the listed header files. I use the following command to compile it to llvm ir code:
clang++ -S -emit-llvm assiral.cpp -o assiral.ll
On compilation I get the following error:
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.
What I expect after running the command is to have the bytecode file generated (.ll file). I've seen many posts where they introduce a flag : '-fms-compatibility-version=19' along with the command. However the flag added gets flagged as an unknown argument. I'm working with MSVS 2017. Maybe I'm using this flag wrong. But I've been at this impasse for a day now. Any help or suggestion would be greatly appreciated.
This was fixed by adding the correct path to the header files in the environment variable INCLUDE. Most of my errors were resolved once I fixed the paths. This includes the error where compiling a c++ file which references certain headers like windows.h gives a file not found.
Link on how to do the same : List all environment variables from command line?
You can also fix another issue which is :
link fatal error lnk1104 cannot open file 'libcmt.lib'
by setting the LIBPATH environment variable to point to the right location of the libcmt.lib file. I found mine at:
C:\Program Files\Microsoft Visual Studio 14.0\VC\lib
These trivial issues left me spending quite a few days to figure out. Hope this saves someone the same trouble.