[clang] [Clang][SYCL] Introduce clang-sycl-linker to link SYCL offloading device code (Part 1 of many) (PR #112245)

[LLVM Continuous Integration via cfe-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `flang-aarch64-latest-gcc` running on `linaro-flang-aarch64-latest-gcc` while building `clang` at step 5 "build-unified-tree".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/130/builds/5578

<details>
<summary>Here is the relevant piece of the build log for the reference</summary>

```
Step 5 (build-unified-tree) failure: build (failure)
...
../llvm-project/llvm/include/llvm/Transforms/IPO/FunctionImport.h:273:33: warning: member ‘llvm::FunctionImporter::ImportListsTy::ImportIDs’ is used uninitialized [-Wuninitialized]
  273 |     ImportListsTy() : EmptyList(ImportIDs) {}
      |                                 ^~~~~~~~~
../llvm-project/llvm/include/llvm/Transforms/IPO/FunctionImport.h: In constructor ‘llvm::FunctionImporter::ImportListsTy::ImportListsTy(size_t)’:
../llvm-project/llvm/include/llvm/Transforms/IPO/FunctionImport.h:274:44: warning: member ‘llvm::FunctionImporter::ImportListsTy::ImportIDs’ is used uninitialized [-Wuninitialized]
  274 |     ImportListsTy(size_t Size) : EmptyList(ImportIDs), ListsImpl(Size) {}
      |                                            ^~~~~~~~~
897.122 [1049/12/6205] Building CXX object tools/clang/tools/clang-installapi/CMakeFiles/clang-installapi.dir/clang-installapi-driver.cpp.o
897.123 [1049/11/6206] Building CXX object tools/clang/tools/clang-shlib/CMakeFiles/clang-cpp.dir/clang-shlib.cpp.o
897.136 [1049/10/6207] Linking CXX executable bin/clang-sycl-linker
FAILED: bin/clang-sycl-linker 
: && /usr/local/bin/c++ -fPIC -fno-semantic-interposition -fvisibility-inlines-hidden -Werror=date-time -fno-lifetime-dse -Wall -Wextra -Wno-unused-parameter -Wwrite-strings -Wcast-qual -Wno-missing-field-initializers -pedantic -Wno-long-long -Wimplicit-fallthrough -Wno-maybe-uninitialized -Wno-nonnull -Wno-class-memaccess -Wno-redundant-move -Wno-pessimizing-move -Wno-noexcept-type -Wdelete-non-virtual-dtor -Wsuggest-override -Wno-comment -Wno-misleading-indentation -Wctad-maybe-unsupported -fdiagnostics-color -ffunction-sections -fdata-sections -fno-common -Woverloaded-virtual -fno-strict-aliasing -O3 -DNDEBUG -Wl,-rpath-link,/home/tcwg-buildbot/worker/flang-aarch64-latest-gcc/build/./lib  -Wl,--gc-sections tools/clang/tools/clang-sycl-linker/CMakeFiles/clang-sycl-linker.dir/ClangSYCLLinker.cpp.o -o bin/clang-sycl-linker  -Wl,-rpath,"\$ORIGIN/../lib:/home/tcwg-buildbot/worker/flang-aarch64-latest-gcc/build/lib:"  lib/libLLVMAArch64CodeGen.so.20.0git  lib/libLLVMAArch64AsmParser.so.20.0git  lib/libLLVMAArch64Disassembler.so.20.0git  lib/libLLVMOption.so.20.0git  lib/libclangBasic.so.20.0git  lib/libLLVMAArch64Desc.so.20.0git  lib/libLLVMAArch64Info.so.20.0git  lib/libLLVMAArch64Utils.so.20.0git  -Wl,-rpath-link,/home/tcwg-buildbot/worker/flang-aarch64-latest-gcc/build/lib && :
/usr/bin/ld: tools/clang/tools/clang-sycl-linker/CMakeFiles/clang-sycl-linker.dir/ClangSYCLLinker.cpp.o: undefined reference to symbol '_ZN4llvm3sys4path8filenameENS_9StringRefENS1_5StyleE'
/usr/bin/ld: /home/tcwg-buildbot/worker/flang-aarch64-latest-gcc/build/./lib/libLLVMSupport.so.20.0git: error adding symbols: DSO missing from command line
collect2: error: ld returned 1 exit status
897.195 [1049/9/6208] Building CXX object tools/clang/tools/clang-refactor/CMakeFiles/clang-refactor.dir/TestSupport.cpp.o
897.252 [1049/8/6209] Generating ../../../../lib/libscanbuild/compilation.py
897.263 [1049/7/6210] Building CXX object tools/clang/tools/libclang/CMakeFiles/libclang.dir/ARCMigrate.cpp.o
897.836 [1049/6/6211] Building CXX object tools/clang/tools/clang-extdef-mapping/CMakeFiles/clang-extdef-mapping.dir/ClangExtDefMapGen.cpp.o
897.864 [1049/5/6212] Building CXX object tools/clang/tools/arcmt-test/CMakeFiles/arcmt-test.dir/arcmt-test.cpp.o
907.573 [1049/4/6213] Building CXX object tools/clang/tools/clang-installapi/CMakeFiles/clang-installapi.dir/Options.cpp.o
907.874 [1049/3/6214] Building CXX object tools/clang/tools/clang-check/CMakeFiles/clang-check.dir/ClangCheck.cpp.o
914.342 [1049/2/6215] Building CXX object tools/clang/tools/clang-scan-deps/CMakeFiles/clang-scan-deps.dir/ClangScanDeps.cpp.o
914.789 [1049/1/6216] Building CXX object tools/clang/tools/clang-installapi/CMakeFiles/clang-installapi.dir/ClangInstallAPI.cpp.o
ninja: build stopped: subcommand failed.

```

</details>

https://github.com/llvm/llvm-project/pull/112245