[CMake] Compile same source file with different flags into the same library

[Matthias Moeller]

I try to write a cmake file for some external library (from the sparse
suite).
In the provided makefile a single source file is compiled twice with
different compiler flags, e.g.,

$(C) -DDINT -c ../Source/amd_aat.c -o amd_i_aat.o
$(C) -DDLONG -c ../Source/amd_aat.c -o amd_l_aat.o

and finally all object files are combined in a single library.


In my CMakeLists.txt I set the list of source files

SET(AMD_SRC
  ${AMD_SOURCE_DIR}/Source/amd_aat.c
  ...)

generate the names for the output files as follows

STRING(REGEX REPLACE "amd_" "amd_i_" AMDI_SRC ${AMD_SRC})
STRING(REGEX REPLACE "amd_" "amd_l_" AMDL_SRC ${AMD_SRC})

and specify the compiler flags accordingly

SET_SOURCE_FILES_PROPERTIES({AMDI_SRC} PROPERTIES COMPILE_FLAGS "-DDINT")
SET_SOURCE_FILES_PROPERTIES({AMDL_SRC} PROPERTIES COMPILE_FLAGS "-DDLONG")

However, the problem is that there are no physical source files named,
e.g. amd_i_aat.c, and hence, CMake produces the following obvious error
message:

CMake Error in CMakeLists.txt:
  Cannot find source file "amd_i_aat.c".  Tried extensions .c .C .c++
  .cc .cpp .cxx .m .M .mm .h .hh .h++ .hm .hpp .hxx .in .txx


Is is possible to tell CMake that the name of the source file differs
from that of the output file?


Best regards,
Matthias