[clang] [llvm] [clang][SPIR-V] Implement -fspv-preserve-interface (PR #196404)

[Diego Novillo via cfe-commits]

dnovillo wrote:

> @dnovillo it seems that this patch breaks the build with `BUILD_SHARED_LIBS`. I had to revert it in #202558 .
> 
> It fails with:
> 
> ```
> : && /opt/rh/gcc-toolset-13/root/usr/bin/c++ -fPIC -fPIC -fno-semantic-interposition -fvisibility-inlines-hidden -Werror=date-time -Wall -Wextra -Wno-unused-parameter -Wwrite-strings -Wcast-qual -Wno-missing-field-initializers -pedantic -Wno-long-long -Wimplicit-fallthrough -Wno-uninitialized -Wno-nonnull -Wno-class-memaccess -Wno-dangling-reference -Wno-redundant-move -Wno-pessimizing-move -Wno-array-bounds -Wno-stringop-overread -Wno-dangling-pointer -Wno-noexcept-type -Wdelete-non-virtual-dtor -Wsuggest-override -Wno-comment -Wno-misleading-indentation -Wctad-maybe-unsupported -fdiagnostics-color -ffunction-sections -fdata-sections -O3 -DNDEBUG  -Wl,-z,defs -Wl,-z,nodelete   -Wl,-rpath-link,/home/botworker/bbot/amdgpu-offload-build-only/build/./lib  -Wl,--gc-sections -shared -Wl,-soname,libLLVMFrontendHLSL.so.23.0git -o lib/libLLVMFrontendHLSL.so.23.0git lib/Frontend/HLSL/CMakeFiles/LLVMFrontendHLSL.dir/CBuffer.cpp.o lib/Frontend/HLSL/CMakeFiles/LLVMFrontendHLSL.dir/HLSLBinding.cpp.o lib/Frontend/HLSL/CMakeFiles/LLVMFrontendHLSL.dir/HLSLResource.cpp.o lib/Frontend/HLSL/CMakeFiles/LLVMFrontendHLSL.dir/HLSLRootSignature.cpp.o lib/Frontend/HLSL/CMakeFiles/LLVMFrontendHLSL.dir/RootSignatureMetadata.cpp.o lib/Frontend/HLSL/CMakeFiles/LLVMFrontendHLSL.dir/RootSignatureValidations.cpp.o  -Wl,-rpath,"\$ORIGIN/../lib:\$ORIGIN/../lib/x86_64-unknown-linux-gnu:/home/botworker/bbot/amdgpu-offload-build-only/build/lib:"  lib/libLLVMCore.so.23.0git  lib/libLLVMBinaryFormat.so.23.0git  lib/libLLVMSupport.so.23.0git  -Wl,-rpath-link,/home/botworker/bbot/amdgpu-offload-build-only/build/lib && :
> /opt/rh/gcc-toolset-13/root/usr/libexec/gcc/x86_64-redhat-linux/13/ld: lib/Frontend/HLSL/CMakeFiles/LLVMFrontendHLSL.dir/CBuffer.cpp.o: in function `llvm::hlsl::CBufferMetadata::removeCBufferGlobalsFromUseList(llvm::Module&)':
> CBuffer.cpp:(.text._ZN4llvm4hlsl15CBufferMetadata31removeCBufferGlobalsFromUseListERNS_6ModuleE+0xce): undefined reference to `llvm::removeFromUsedLists(llvm::Module&, llvm::function_ref<bool (llvm::Constant*)>)'
> ```
> 
> I've tried to add `TransformUtils` in the dependencies of `LLVMFrontendHLSL`, but we get a circular dependency:
> 
> ```
> CMake Error: The inter-target dependency graph contains the following strongly connected component (cycle):
>   "LLVMFrontendHLSL" of type SHARED_LIBRARY
>     depends on "LLVMTransformUtils" (weak)
>   "LLVMTransformUtils" of type SHARED_LIBRARY
>     depends on "LLVMAnalysis" (weak)
>   "LLVMAnalysis" of type SHARED_LIBRARY
>     depends on "LLVMFrontendHLSL" (weak)
> At least one of these targets is not a STATIC_LIBRARY.  Cyclic dependencies are allowed only among static libraries.
> CMake Generate step failed.  Build files cannot be regenerated correctly.
> ```

Actually, I do not think this was due to this PR. The linker failure is in `CBuffer.cpp`, which #196404 does not touch. I think this may have been broken by [`d439fac25c03`](https://github.com/llvm/llvm-project/commit/d439fac25c03), which added `removeFromUsedLists` to `LLVMFrontendHLSL/CBuffer.cpp` without updating `LLVMFrontendHLSL`'s `LINK_COMPONENTS`.

Adding `LLVMTransformUtils` to `LLVMFrontendHLSL` creates a cycle through `LLVMAnalysis`.  Once that is fixed, this one  can be re-submitted without changes.

https://github.com/llvm/llvm-project/pull/196404