Update AnnotationToMetadataPass to handle pointer casts in llvm.global.annotations

[ben-clayton]

A recent change to LLVM introduces pointer address space casts on the function pointer.
Use stripPointerCasts() on the operand to make the dyn_cast work.

[rjodinchr]

Should we also update LLVM to make sure that all the tests are passing with this new version of LLVM and that fix?

[ben-clayton]

Updating LLVM might be a good idea, but please can we do this as a followup?
I've been testing internally at Google with this, as a recent LLVM roll broke everything clspv related. There's some urgency in getting a fix landed.

I believe this fix to be backwards-compatible.

[rjodinchr]

Updating LLVM might be a good idea, but please can we do this as a followup?

Sure, I'll merge it once the checks are complete.
I'll update LLVM after it.

[ben-clayton]

Updating LLVM might be a good idea, but please can we do this as a followup?

Sure, I'll merge it once the checks are complete. I'll update LLVM after it.

Thank you!

[ben-clayton]

CI-clvk-ubuntu-clang-debug failure seems unrelated:

/tmpfs/src/github/clvk/external/SPIRV-LLVM-Translator/lib/SPIRV/SPIRVToLLVMDbgTran.cpp:1568:13: error: variable 'DbgDeclare' with type 'auto *' has incompatible initializer of type 'llvm::DbgInstPtr' (aka 'PointerUnion')
      auto *DbgDeclare = getDIBuilder(DebugInst).insertDeclare(
            ^            ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/tmpfs/src/github/clvk/external/SPIRV-LLVM-Translator/lib/SPIRV/SPIRVToLLVMDbgTran.cpp:1574:12: error: no viable conversion from returned value of type 'llvm::DbgInstPtr' (aka 'PointerUnion') to function return type 'llvm::Instruction *'
    return getDIBuilder(DebugInst).insertDeclare(
           ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/tmpfs/src/github/clvk/external/SPIRV-LLVM-Translator/lib/SPIRV/SPIRVToLLVMDbgTran.cpp:1583:11: error: variable 'DbgValIntr' with type 'auto *' has incompatible initializer of type 'llvm::DbgInstPtr' (aka 'PointerUnion')
    auto *DbgValIntr = getDIBuilder(DebugInst).insertDbgValueIntrinsic(
          ^            ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
3 errors generated.

[rjodinchr]

CI-clvk-ubuntu-clang-debug is expected to fail at the moment, CI-amber-ubuntu-gcc-release as well.