Compilation of rc-3.5.0 on Mac M1 2020

[andrew-platt]

Bug description
A new clone of rc-3.5.0 does not directly compile on MacbookPro17,1 (early M1 chipset) with Monterey

From HomeBrew:

• CMake v 3.22.4
• gcc/gfortran v 12.2
• make 3.8.1
• XCode command line 13.4?

Interestingly v 3.4.1 compiles just fine on this hardware. So there must be something in the rc-3.5.1 changes to CMake that cause linking issues on this specific hardware configuration.

To troubleshoot, we checked everything in CMakeCache.txt, specified exact paths to all compilers and linkers, and checked the SDK version. Nothing appeared out of the ordinary in any of that. We also compared the link.txt and other files in CMake build system with a clean compile of rc-3.5.0 on an Intel based Mac, but did not find anything unusual.

I will attempt to commandeer a 2020 M1 and attempt this build process to reproduce.

To Reproduce
Steps to reproduce the behavior:

1. Fresh clone of OpenFAST from GH
2. checkout branch rc-3.5.0
3. mkdir build; cmake .. -DBUILD_SHARED=On; make -j4 openfastlib
4. Everything compiles, but linking fails

After checking this, git checkout v3.4.1 followed by removing everything in build and repeating step 3 above works just fine.

OpenFAST Version
rc-3.5.0 branch of OpenFAST

[deslaughter]

I think the CMake flag -DBUILD_SHARED=On needs to be changed to -DBUILD_SHARED_LIBS=On.

When I ran the CMake command in the "To Reproduce" section, it picked the following compilers

-- The CXX compiler identification is AppleClang 14.0.0.14000029
-- The C compiler identification is AppleClang 14.0.0.14000029
-- The Fortran compiler identification is GNU 12.2.0

Usually when I run the build on an M1 Mac, I set the C and C++ compilers to be gcc and g++, respectively.

@andrew-platt , do you know which compilers were used the bug report compilation?

I was able to reproduce the error with Undefined symbols for architecture arm64 in libmaplib.dylib. I expect this is an issue with the object libraries, but I'll have to do some more digging.

[andrew-platt]

That was a typo on my part, we used -DBUILD_SHARED_LIBS=On (I was typing from memory).

The CXX and C compilers were picked up by cmake as g++-12 and gcc-12 respectively. We double checked these in CMakeCache.txt to be certain.

Thanks for checking looking at this!

[andrew-platt]

The linker used was from /usr/bin/ld for both the 3.5.0 (failed linking), and in the 3.4.1 (successful compilation). I suspect you are right and it is an issue with the object libraries added in 3.5.0.

[deslaughter]

This issue should be resolved with PR #1555 which is now in the dev branch. Please give it a try when you have a chance.

[reos-rcrozier]

This is probably just an issue with the order of compilation and ensuring the dependencies are correct. Object libraries were added for very good reasons on Linux.