Processing assembly files with C Preprocessor statements


I have assembly files(*.asm extension) with C preprocessor statements. These files are recognized by CMAKE as ASM files. On compilers where the control program/compiler itself supports pre-processing and assembling I do not run into any problems. On the compilers where the compiler only supported preprocessing and assembling has to be done by the seperate assembler, I run into problems(as I can either send the files to the compiler to preprocess or to the assembler to assembler but not both).

I read up on which is a similar problem. But, I did not find a recommended way to solve the problem.

Can someone point me to the right direction on what would be the best way to preprocess the .asm using the CMAKE_C_COMPILER and then piping the output over to the CMAKE_ASM_COMPILER for assembling.


I don’t think CMake has a preprocessing step for ASM files for use in general. @brad.king?

If that really is the case,what is the recommended way to workaround it ?

CMake does not model explicit preprocessing in general. ASM sources may be preprocessed if the assembler itself supports doing so. Many assemblers support preprocessing upper-case extensions, particularly when the C compiler itself is used as the assembler.

Otherwise, one could look at using add_custom_command to run the C preprocessor first and generate an already-preprocessed source that is then given to add_library or add_executable as an ASM source.

Our customer faced the same problem.
Assembler preprocessing is done by gcc and, most probably, armclang if -x assembler-with-cpp CLI options are provided. So for me add_compile_options($<$<COMPILE_LANGUAGE:ASM>:-x$<SEMICOLON>assembler-with-cpp>) clause does the trick.