Issue with linking libraries built with gnat - linker

Question

When trying to build some test cases (just programs written in Ada), I get the following error:
gcc -c -shared decimaltests.adb
gnatbind -x decimaltests.ali
gnatlink decimaltests.ali -lGenerics -lNumerics -lTesting
/usr/bin/ld: decimaltests: hidden symbol `_Unwind_Resume' in
/usr/lib/gcc/x86_64-pc-linux-gnu/7.2.1/libgcc_eh.a(unwind-dw2.o) is referenced by DSO
/usr/bin/ld: final link failed: Bad value
collect2: error: ld returned 1 exit status
gnatlink: error when calling /usr/bin/gcc
gnatmake: *** link failed.
I'm building them with gnatmake -shared *.ad{b,s} -largs -lGenerics -lNumerics -lTesting Clearly this isn't a problem with building the sources, but just to further confirm that, I copied the sources into this directory and built using gnatmake -shared *.ad{b,s} which built the tests just fine.
The dependent libraries are built and installed into a path gnat searches through. It doesn't seem to be an issue of not finding those. Not sure what's going on here.
All the libraries are built with gnatmake -O2 -fPIC -shared *.ad{b,s} as well as any relevant library dependencies. All libraries that depend on these can still be built. It's only even programs that depend on the libraries that throw this error, and always the same error.
Update: Building the libraries using gprbuild and then installing them with gprinstall seems to work similarly, except now the error is as follows:
decimaltests.o: In function `_ada_decimaltests':
decimaltests.adb:(.text+0x43): undefined reference to `testing__start'
decimaltests.adb:(.text+0x4a): undefined reference to
`generics__testing__default_tolerance'
decimaltests.adb:(.text+0x9e): undefined reference to
`generics__testing__default_tolerance'
decimaltests.adb:(.text+0x108): undefined reference to
`generics__testing__default_tolerance'
decimaltests.adb:(.text+0x172): undefined reference to
`generics__testing__default_tolerance'
decimaltests.adb:(.text+0x1dc): undefined reference to
`generics__testing__default_tolerance'
decimaltests.o:decimaltests.adb:(.text+0x23f): more undefined references to
`generics__testing__default_tolerance' follow
decimaltests.o: In function `_ada_decimaltests':
decimaltests.adb:(.text+0x14f5): undefined reference to `testing__stop'
/usr/lib/numerics//libNumerics.so: undefined reference to
`generics__testing__not_started#SYMS'
/usr/lib/numerics//libNumerics.so: undefined reference to
`generics__testing__pass#SYMS'
/usr/lib/numerics//libNumerics.so: undefined reference to
`generics__testing__fail#SYMS'
collect2: error: ld returned 1 exit status
gprbuild: link of decimaltests.adb failed
So I looked through the symbols table for both build methods and noticed, in both cases, the symbol most definitely exists, but the reference to it seems to be the wrong location. I'll try building on different platforms/compilers and update again if anything relevant comes up.

Answer 1

Both processes correctly build the libraries and test programs, and the test programs run properly, on different platforms. To further confirm that this is a bug, I've installed a different GCC toolchain and repeated the builds under the original platform, and this problem did not arise. I'll be filing a bug report.