Passing additional CMake arguments to Native build

[alpencolt]

build-native.sh has options cmakeargs for passing additional arguments to CMake. But if I want add -D_FORTIFY_SOURCE=2 option to CXXFLAGS it will be applied to corefx/src/Native/Unix/configure.cmake (which cause errors on test programs compilation).
If I add this option to corefx/src/Native/Unix/CMakeLists.txt it will applied to source code only (as expected).

Is there other way to pass this and others options to build without patching source code? If not is it possible to change cmakeargs behavior or add some other logic?

This behavior is the same for CoreCLR too.

cc @BruceForstall @jkotas
cc @chunseoklee

[jkotas]

@janvorli

[BruceForstall]

@alpencolt I'm afraid you're beyond my level of cmake / build system expertise.

[janvorli]

Hmm, I was pretty sure I've replied to this yesterday, but the window probably get lost before I have sent it.
I am not sure I understand how defining a cmake variable using the cmakeargs automatically results in setting the compiler option. You need to have your own code in the cmake scripts to set the compiler define if the cmake variable is set, right? And then you can choose where to put it and what to influence. @alpencolt can you please explain to me what I am missing?

[alpencolt]

@janvorli Tizen project is needed to set some global compiler and linker options (e.g. D_FORTIFY_SOURCE=2) for all modules included to OS, sometimes it might be list of options (-fstack-protector-strong -D_FORTIFY_SOURCE=2 or others). This list can be different for different releases and we don't really modify CoreCL/FX sources for this purpose(it's worth case).

Better option is passing this additional options and defines through global variable or some command line key and read them in CMakeLists.txt. The main point we are needed is applying this compiler/linker flags only to CoreCLR/FX source and not to configure.cmake. Since configure.cmake failed on easiest checks.
cmakeargs option doesn't provide necessary functionality (may be we use it wrong way?). It isn't pass arguments as we expected and it doesn't work with list of options (e.g. CXXFLAGS+=-fstack-protector-strong -D_FORTIFY_SOURCE=2).

Can we solve this issue by existed tools? If not can we add this functionality to upstream?

[janvorli]

@alpencolt I think the best solution for this would be to pass a single cmake variable containing the compiler options and then using them in the CMakeLists.txt where you want them to take effect.
So, we could add support for that to coreclr / corefx and then you can pass whatever options you want through that without further touching the sources in the future.
So we would add a cmake variable named e.g. CLR_ADDITIONAL_COMPILER_OPTIONS. On the build command line, you would add cmakeargs "-DCLR_ADDITIONAL_COMPILER_OPTIONS=-fstack-protector-strong;-D_FORTIFY_SOURCE=2". Please note the ; separating the options and the quotes around the whole option, they are necessary to ensure that the options are correctly passed to cmake.
In the compileoptions.cmake, we would add add_compile_options(${CLR_ADDITIONAL_COMPILER_OPTIONS}) inside the initial if (CLR_CMAKE_PLATFORM_UNIX).
That should be all that's needed to enable passing in any compiler options you want.

[alpencolt]

@janvorli great! Thank you.
I will prepare PR.

[alpencolt]

@janvorli corefx/Tools/run.exe which is called from corefx/run.sh doesn't keep quotes on Linux. So I call for example:

./build-native.sh -Release -buildArch=armel -- clang3.8 cmakeargs '-DCLR_FIRST=1 -DCLR_SECOND=2'

String -DCLR_FIRST=1 -DCLR_SECOND=2 can be handled as one argument (by using $7 or other number depending from position) in all scripts before corefx/Tools/run.exe. But after -DCLR_FIRST=1 and -DCLR_SECOND=2 are two different arguments ($7 and $8).
Does it OK? How can I fix run.exe behavior?

[janvorli]

The solution is simple - pass the two defines separately:

./build-native.sh -Release -buildArch=armel -- clang3.8 cmakeargs -DCLR_FIRST=1 cmakeargs -DCLR_SECOND=2