Remove gcc dependencies from apt.llvm.org

[llvmbot]

Bugzilla Link	46318
Version	unspecified
OS	Linux
Reporter	LLVM Bugzilla Contributor
CC	@LebedevRI,@mclow,@sylvestre

Extended Description

The packages available on apt.llvm.org have unnecessary dependencies to gcc artifacts, especially libgcc2 and crtbegin/crtend (and possibly libstdc++).
Additionally contrary to what is advertised compiler-rt packages are missing (while not strictly being the theme of this issue polly packages are missing too).
The current situation should be improved in two ways (possibly steps):

1. The compiler-rt packages should be provided as advertised. Optimally they should contain implementations of crtbegin.o and crtend.o.
2. All binaries (executables and libraries) provided on this site should depend on compiler-rt only i.e. no more dependencies to libgcc2 or the gcc versions of crtbegin / crtend. Additionally all binaries should depend (if applicable) on llvm libcxx and not gcc libstdc++.
   This issue is an offspring of a discussion with Sylvestre Ledru.

[LebedevRI]

The packages available on apt.llvm.org have unnecessary dependencies to gcc
artifacts, especially libgcc2 and crtbegin/crtend (and possibly libstdc++).
Additionally contrary to what is advertised compiler-rt packages are missing
(while not strictly being the theme of this issue polly packages are missing
too).
The current situation should be improved in two ways (possibly steps):

1. The compiler-rt packages should be provided as advertised. Optimally they
   should contain implementations of crtbegin.o and crtend.o.
2. All binaries (executables and libraries) provided on this site should
   depend on compiler-rt only i.e. no more dependencies to libgcc2 or the gcc
   versions of crtbegin / crtend.

Additionally all binaries should depend (if
applicable) on llvm libcxx and not gcc libstdc++.

How would that work?
I strongly believe you can't mix c++ std implementations.

This issue is an offspring of a discussion with Sylvestre Ledru.

[llvmbot]

Roman Lebedev: There is nothing to be mixed, my proposal / issue says the direct opposite: Having a llvm / clang distribution without any dependence to libstdc++, all libc++ only.

[LebedevRI]

Roman Lebedev: There is nothing to be mixed, my proposal / issue says the
direct opposite: Having a llvm / clang distribution without any dependence
to libstdc++, all libc++ only.

The thing is, this is transitive issue.
As long as any of your dependencies linked to libstdc++,
you can't link to libc++ instead. And they already did:

$ ldd /usr/bin/clang-11
<...>
libz3.so.4 => /lib/x86_64-linux-gnu/libz3.so.4 (0x00007fec42c00000)
$ ldd /lib/x86_64-linux-gnu/libz3.so.4
<...>
libstdc++.so.6 => /lib/x86_64-linux-gnu/libstdc++.so.6 (0x00007f31b5848000)

[llvmbot]

Roman Lebedev: 1) Lets wait what the others say 2) If true i could not link against libc++ at all? 3) Even if this were the case it would be solvable (at a higher cost).

[sylvestre]

what would be the options to do this?

[firewave]

Is this still an issue?