[CMake] Cross compiling in Win32 environment doesn't work

[Alexander Neundorf]

Hi,

can you please adjust your mail client so it doesn't send HTML mails ?

On Monday, September 19, 2011 04:57:32 PM Martin Kupke wrote:
>  That's a hint, I changed my toolchain file "toolchain_ppc.cmake" to the
> following: INCLUDE(CMakeForceCompiler)
>  set(CMAKE_SYSTEM_NAME "Discovery")
> 
>  if(CMAKE_CROSSCOMPILING)
>  message("Cross Compiling")
>  endif(CMAKE_CROSSCOMPILING)
> 
>  # which compilers to use for C and C++
>  set(CMAKE_C_COMPILER "C:/WindRiver/diab/5.9.0.0/WIN32/bin/dcc.exe")
>  set(CMAKE_FORCE_C_COMPILER "C:/WindRiver/diab/5.9.0.0/WIN32/bin/dcc.exe")
>  set(CMAKE_C_FLAGS "-tPPCVLEEN:simple")
> 
>  Then I created a folder with the name Platform containing a file with
> CMAKE_SYSTEM_NAME which is Discovery -> at this point I had already
> problems, because CMake doesn't use as described the filename with .cmake
> extension. The filename in the Platform folder has to have the name from
> CMAKE_SYSTEM_NAME without the extension .cmake (even the documentation
> says something different). I checked this by adding the output of a
> message("SYSTEM_NAME=Discovery").

The filename must be Discovery.cmake in your case.
Did you say this didn't work ?
This file must be either in the cmake Modules/Platfom/ directory, or in a 
subdirectory Platform/ of a directory which is in CMAKE_MODULE_PATH.
 
>  The Platform/Discovery file contains the lines:
>  message("SYSTEM_NAME=Discovery")
>  set(CMAKE_FORCE_C_COMPILER "C:/WindRiver/diab/5.9.0.0/WIN32/bin/dcc.exe")
>  set(CMAKE_C_COMPILER "C:/WindRiver/diab/5.9.0.0/WIN32/bin/dcc.exe")
>  set(CMAKE_C_FLAGS "-tPPCVLEEN:simple")
>  set(CMAKE_FORCE_C_FLAGS "-tPPCVLEEN:simple")
>  set(CMAKE_FORCE_CXX_COMPILER
> "C:/WindRiver/diab/5.9.0.0/WIN32/bin/dcc.exe") set(CMAKE_CXX_COMPILER
> "C:/WindRiver/diab/5.9.0.0/WIN32/bin/dcc.exe") set(CMAKE_CXX_FLAGS
> "-tPPCVLEEN:simple")
>  set(CMAKE_MAKE_PROGRAM "D:/novero/Discovery/impl/win32/nmake/nmake.exe")

That last line should not be necessary.

>  Then I call from the command line the CMake tool with the parameters:
>  D:\novero\Discovery\impl\target\CarIF_Appl\output>cmake -G "NMake
> Makefiles" -D CMAKE_TOOLCHAIN_FILE="..\toolchain_ppc.cmake" ..
> 
>  The following output will be produced:
>  ********************* snip output *********************
>  Cross Compiling
>  -- The C compiler identification is unknown
>  -- The CXX compiler identification is unknown
>  SYSTEM_NAME=Discovery
>  SYSTEM_NAME=Discovery
>  -- Check for working C compiler:
> C:/WindRiver/diab/5.9.0.0/WIN32/bin/dcc.exe System is unknown to cmake,
> create:
>  Platform/Discovery to use this system, please send your config file to
> cmake at www .cmake.org so it can be added to cmake
>  -- Check for working C compiler:
> C:/WindRiver/diab/5.9.0.0/WIN32/bin/dcc.exe -- broken
>  CMake Error at C:/Program Files/CMake
> 2.8/share/cmake-2.8/Modules/CMakeTestCComp iler.cmake:52 (MESSAGE):
>    The C compiler "C:/WindRiver/diab/5.9.0.0/WIN32/bin/dcc.exe" is not able
> to compile a simple test program.
> 
>    It fails with the following output:
> 
>     Change Dir:
> D:/novero/Discovery/impl/target/CarIF_Appl/output/CMakeFiles/CMak eTmp
> 
>    Run Build Command:nmake /NOLOGO "cmTryCompileExec\fast"
> 
>          nmake -f CMakeFiles\cmTryCompileExec.dir\build.make /nologo -L
>    CMakeFiles\cmTryCompileExec.dir\build
> 
>          "C:\Program Files\CMake 2.8\bin\cmake.exe" -E
> cmake_progress_report
> D:\novero\Discovery\impl\target\CarIF_Appl\output\CMakeFiles\CMakeTmp\CMak
> eFil es
>    1
> 
>    Building C object CMakeFiles/cmTryCompileExec.dir/testCCompiler.c.obj
> 
>          C:\WindRiver\diab\5.9.0.0\WIN32\bin\dcc.exe -o
>    CMakeFiles\cmTryCompileExec.dir\testCCompiler.c.obj -c
>   
> D:\novero\Discovery\impl\target\CarIF_Appl\output\CMakeFiles\CMakeTmp\test
> CCom piler.c
> 
> 
>    Target Unknown.  Use the -t option or set a default target with dctrl -t
> 
>    NMAKE : fatal error U1077: 'C:\WINDOWS\system32\cmd.exe' : return code
>    '0x1'
> 
>    Stop.
> 
>    NMAKE : fatal error U1077: 'C:\WINDOWS\system32\cmd.exe' : return code
>    '0x2'
> 
>    Stop.
> 
>    CMake will not be able to correctly generate this project.
>  Call Stack (most recent call first):
>    CMakeLists.txt:2 (project)
> 
> 
>  -- Configuring incomplete, errors occurred!
>  You have changed variables that require your cache to be deleted.
>  Configure will be re-run and you may have to reset some variables.
>  The following variables have changed:
>  CMAKE_CXX_COMPILER= cl
> 
>  -- Generating done
>  -- Build files have been written to:
> D:/novero/Discovery/impl/target/CarIF_Appl/ output
> 
>  ********************* snap output *********************
> 
>  1.) with the output SYSTEM_NAME=Discovery I can see that the platform file
> is used 2.) the compilation doesn't complete, because the CMAKE_C_FLAGS
> are still not used 

They are initialized later on.
There is a set of variables which are used for initialization, I think it's 
name is CMAKE_C_FLAGS_INIT .

> 3.) why do I have to have a CXX (C++) compiler, even if
> I don't need it in my embedded solution 

By default cmake enables C and C++.
If you put a 
project(MyProject C)
into your toplevel CMakeLists.txt, only the C language will be enabled, not 
C++.

> 4.) is there any reason why CMake
> needs to know my system? I want just to compile some files... (wondering)

Yes. It needs this information to be able to know e.g. search locations for 
the find_xxx() calls, for file prefixes and suffixes, for knowing the compiler 
flags for this compiler on this OS 

Alex