[CMake] Compiler varience?

[Preston A. Elder]

Hey,

Is there a module out there that will supply pre-defined flags for
different compilers?

I made a start on one, but I can't believe I am the first, but a snippet
of what I have been making:

if (${CMAKE_C_COMPILER_ID} STREQUAL "GNU")
    SET(C_WARN_DEF "-W")
    SET(C_WARN_FULL "-W -Wall -Wshadow")
    SET(C_WARN_NONE "-w")
    SET(C_WARN_ERROR "-Werror")

    SET(C_OPT_DEBUG "-g")
    SET(C_OPT_NONE "-O0")
    SET(C_OPT_SPEED "-O3")
    SET(C_OPT_SIZE "-Os")

    SET(C_WORD32 "-m32")
    SET(C_WORD64 "-m64")

elseif (${CMAKE_C_COMPILER_ID} STREQUAL "MSVC")
    SET(C_WARN_DEF "/W3")
    SET(C_WARN_FULL "/W4")
    SET(C_WARN_NONE "/w")
    SET(C_WARN_ERROR "/WX")

    SET(C_OPT_DEBUG "/Z7")
    SET(C_OPT_NONE "/Od")
    SET(C_OPT_SPEED "/O2")
    SET(C_OPT_SIZE "/O1")

    SET(C_WORD32 "")
    SET(C_WORD64 "")

endif ()

In other words, I want something that will set things like the above for
EACH compiler (as I said, I have made some progress).  The WORD32/WORD64
also need linker flags too.  Plus going even further than the above (for
doing things like enabling platform-specific optimizations, like
-march=i686 on gcc, maybe in C_OPT_CPU) would be nice.  FYI, I have made
the CXX equivalents too.

I only started using cmake this weekend, so my implementation may be a
little naive and simplistic.  But before I go completely crazy with
this, I wanted to know if it has been done.  It is kind of silly that
the end-user has to know the flags for EACH compiler that may be used to
compile their project to do things like enable ALL warnings, or optimize
for size.  It also seems a little odd that each end-user would have to
write the if/elseif/endif code to accommodate each compiler themselves.

I searched the bug database, and did not see any open issues relating to
this, and the mailing list is not easily searchable (though google
didn't turn up any results).

FYI, I just moved from bjam to cmake - mainly because bjam is a little
difficult to use and is quirky with relation to paths and such.  Cmake
is much more user-friendly, but does not seem to be as refined as far as
handling different compiler flags as above.

FYI 2, yes, I know I can use different settings of CMAKE_BUILD_TYPE to
change the opimization/debug symbols flags, but that's only part of the
story (there is nothing to change warning levels or force a 32-bit
compile on a 64-bit machine).  And if I was to make my own build type
(eg. RELEASE32) I would need the flags above anyway to remain compiler
agnostic.

PreZ :)
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