Cross compiling for x64_arm with MSVC tools on Windows - windows

Question

I am using MSVC command line tools to try to compile a simple c++ based program for arm/arm64 on a x64 machine. Even after using the toolchain file, the compiler definition is not getting updated and the default compiler for host is being used. Please read further for more information on the issue.
Testcase:
#include <iostream>
using namespace std;
int main()
{
cout << "Hello world!" << endl;
}
CMakelists.txt:
cmake_minimum_required(VERSION 3.14.3)
project(hello C CXX ASM)
enable_language(ASM)
add_executable(hello hello.cpp)
Toolchain file:
cmake_minimum_required(VERSION 3.14.3)
set(CMAKE_CROSSCOMPILING 1)
set(CMAKE_SYSTEM_NAME Windows)
set(CMAKE_SYSTEM_PROCESSOR ARM)
set(CMAKE_SYSTEM_VERSION 10.0)
set(CMAKE_C_COMPILER "C:/Program Files (x86)/Microsoft Visual Studio/2019/BuildTools/VC/Tools/MSVC/14.28.29333/bin/Hostx64/arm/cl.exe")
set(CMAKE_CXX_COMPILER "C:/Program Files (x86)/Microsoft Visual Studio/2019/BuildTools/VC/Tools/MSVC/14.28.29333/bin/Hostx64/arm/cl.exe")
set(CMAKE_ASM_COMPILER "C:/Program Files (x86)/Microsoft Visual Studio/2019/BuildTools/VC/Tools/MSVC/14.28.29333/bin/Hostx64/arm/cl.exe")
The command I used to build this:
cmake.exe -S C:\hello -B C:\hello\output_dir.cmake -DCMAKE_TOOLCHAIN_FILE=C:\hello\Toolchain.cmake
With the above configuration, I am able to build a x64 based application but not a cross compiled ARM based one. From console logs, I see that the c and c++ compiler definition is not overwritten but ASM compiler is overwritten using the toolchain file.
-- Building for: Visual Studio 16 2019
-- Selecting Windows SDK version 10.0.18362.0 to target Windows 10.0.
-- The C compiler identification is MSVC 19.28.29336.0
-- The CXX compiler identification is MSVC 19.28.29336.0
-- The ASM compiler identification is MSVC
-- Found assembler: C:/Program Files (x86)/Microsoft Visual Studio/2019/BuildTools/VC/Tools/MSVC/14.28.29333/bin/Hostx64/arm/cl.exe
-- Check for working C compiler: C:/Program Files (x86)/Microsoft Visual Studio/2019/BuildTools/VC/Tools/MSVC/14.28.29333/bin/Hostx64/x64/cl.exe
-- Check for working C compiler: C:/Program Files (x86)/Microsoft Visual Studio/2019/BuildTools/VC/Tools/MSVC/14.28.29333/bin/Hostx64/x64/cl.exe - works
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - done
-- Detecting C compile features
-- Detecting C compile features - done
-- Check for working CXX compiler: C:/Program Files (x86)/Microsoft Visual Studio/2019/BuildTools/VC/Tools/MSVC/14.28.29333/bin/Hostx64/x64/cl.exe
-- Check for working CXX compiler: C:/Program Files (x86)/Microsoft Visual Studio/2019/BuildTools/VC/Tools/MSVC/14.28.29333/bin/Hostx64/x64/cl.exe - works
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Detecting CXX compile features
-- Detecting CXX compile features - done
-- Configuring done
-- Generating done
-- Build files have been written to: C:/hello/output_dir.cmake
I am not sure what is missing in this configuration. Can anyone please help from their experience?

Answer 1

Thanks for your answers.
Using set(CMAKE_GENERATOR_PLATFORM ARM64 CACHE INTERNAL "") in my toolchain file worked for me, following are the logs picking correct compiler:
> -- Building for: Visual Studio 16 2019
> -- Selecting Windows SDK version 10.0.18362.0 to target Windows 10.0.
> -- The C compiler identification is MSVC 19.28.29336.0
> -- The CXX compiler identification is MSVC 19.28.29336.0
> -- The ASM compiler identification is MSVC
> -- Found assembler: C:/Program Files (x86)/Microsoft Visual Studio/2019/BuildTools/VC/Tools/MSVC/14.28.29333/bin/Hostx64/arm/cl.exe
> -- Check for working C compiler: C:/Program Files (x86)/Microsoft Visual
> Studio/2019/BuildTools/VC/Tools/MSVC/14.28.29333/bin/Hostx64/arm64/cl.exe
> -- Check for working C compiler: C:/Program Files (x86)/Microsoft Visual
> Studio/2019/BuildTools/VC/Tools/MSVC/14.28.29333/bin/Hostx64/arm64/cl.exe
> - works
> -- Detecting C compiler ABI info
> -- Detecting C compiler ABI info - done
> -- Detecting C compile features
> -- Detecting C compile features - done
> -- Check for working CXX compiler: C:/Program Files (x86)/Microsoft Visual
> Studio/2019/BuildTools/VC/Tools/MSVC/14.28.29333/bin/Hostx64/arm64/cl.exe
> -- Check for working CXX compiler: C:/Program Files (x86)/Microsoft Visual
> Studio/2019/BuildTools/VC/Tools/MSVC/14.28.29333/bin/Hostx64/arm64/cl.exe
> - works
> -- Detecting CXX compiler ABI info
> -- Detecting CXX compiler ABI info - done
> -- Detecting CXX compile features
> -- Detecting CXX compile features - done
> -- Configuring done
> -- Generating done
> -- Build files have been written to: C:/hello/output_dir.cmake