This patch supports GNU ld on Solaris in addition to Solaris ld, the
default.
- Linker selection is dynamic: one can switch between Solaris ld and GNU ld
at runtime, with the default selectable with `-DCLANG_DEFAULT_LINKER`.
- Testcases have been adjusted to test both variants in case there are
differences.
- The `compiler-rt/cmake/config-ix.cmake` and
`llvm/cmake/modules/AddLLVM.cmake` changes to restrict the tests to
Solaris ld are necessary because GNU accepts unknown `-z` options, but
warns every time they are used, creating a lot of noise. Since there
seems to be no way to check for those warnings in
`llvm_check_compiler_linker_flag` or `llvm_check_compiler_linker_flag`, I
restrict the cmake tests to Solaris ld in the first place.
- The changes to `clang/test/Driver/hip-link-bundle-archive.hip` and
`flang/test/Driver/linker-flags.f90` are required when LLVM is built with
`-DCLANG_DEFAULT_LINKER=gld` on Solaris: `MSVC.cpp`
`visualstudio::Linker::ConstructJob` ultimately calls
`GetProgramPath("gld")`, resulting in a search for `gld`, which exists in
`/usr/bin/gld` on Solaris. With `-fuse-ld=`, this doesn't happen and the
expected `link` is returned.
- `compiler-rt/test/asan/TestCases/global-location-nodebug.cpp` needs to
enforce the Solaris ld, otherwise the test would `XPASS` with GNU ld
which has the `-S` semantics expected by the test.
Tested on `amd64-pc-solaris2.11` and `sparcv9-sun-solaris2.11` with both
`-DCLANG_DEFAULT_LINKER=gld` and the default, and `x86_64-pc-linux-gnu`.
No regressions in either case.
Differential Revision: https://reviews.llvm.org/D85309
d39a9e3b4d