[compiler-rt][MSVC] Conditionally remove emupac.cpp for msvc

[zacklj89]

#148094 introduces logic for emulated PAC, which utilizes language extensions not available on MSVC.

[zacklj89]

I'll go ahead and merge here since this is a low-risk change that should only affect MSVC.

[nico]

"MSVC" is true both for msvc and clang-cl. Do you want to exclude this for clang-cl too? (I.e. is this about a cl.exe limitation, or a PE/COFF limitation?)

[zacklj89]

@nico thanks, I didn't know they shared that evaluation here!

clang-cl uses the MSVC-style inline assembly syntax, I think (?), so this should also apply for it as well.

[llvm-ci]

LLVM Buildbot has detected a new failure on builder premerge-monolithic-linux running on premerge-linux-1 while building compiler-rt at step 7 "test-build-unified-tree-check-all".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/153/builds/38935

Here is the relevant piece of the build log for the reference

Step 7 (test-build-unified-tree-check-all) failure: test (failure)
...
PASS: lld :: COFF/entry-weak-external.s (98800 of 101788)
PASS: lld :: COFF/empty-subsection.s (98801 of 101788)
PASS: lld :: COFF/dllimport-gc.test (98802 of 101788)
PASS: lld :: COFF/export-armnt.yaml (98803 of 101788)
PASS: lld :: COFF/exclude-symbols.s (98804 of 101788)
PASS: lld :: COFF/eh_frame_suffix_sorting.s (98805 of 101788)
PASS: lld :: COFF/exclude-symbols-embedded.s (98806 of 101788)
PASS: lld :: COFF/empty-section-decl.yaml (98807 of 101788)
PASS: lld :: COFF/driver.test (98808 of 101788)
TIMEOUT: MLIR :: Examples/standalone/test.toy (98809 of 101788)
******************** TEST 'MLIR :: Examples/standalone/test.toy' FAILED ********************
Exit Code: 1
Timeout: Reached timeout of 60 seconds

Command Output (stdout):
--
# RUN: at line 1
"/etc/cmake/bin/cmake" "/build/buildbot/premerge-monolithic-linux/llvm-project/mlir/examples/standalone" -G "Ninja"  -DCMAKE_CXX_COMPILER=/usr/bin/clang++ -DCMAKE_C_COMPILER=/usr/bin/clang  -DLLVM_ENABLE_LIBCXX=OFF -DMLIR_DIR=/build/buildbot/premerge-monolithic-linux/build/lib/cmake/mlir  -DLLVM_USE_LINKER=lld  -DPython3_EXECUTABLE="/usr/bin/python3.10"
# executed command: /etc/cmake/bin/cmake /build/buildbot/premerge-monolithic-linux/llvm-project/mlir/examples/standalone -G Ninja -DCMAKE_CXX_COMPILER=/usr/bin/clang++ -DCMAKE_C_COMPILER=/usr/bin/clang -DLLVM_ENABLE_LIBCXX=OFF -DMLIR_DIR=/build/buildbot/premerge-monolithic-linux/build/lib/cmake/mlir -DLLVM_USE_LINKER=lld -DPython3_EXECUTABLE=/usr/bin/python3.10
# .---command stdout------------
# | -- The CXX compiler identification is Clang 16.0.6
# | -- The C compiler identification is Clang 16.0.6
# | -- Detecting CXX compiler ABI info
# | -- Detecting CXX compiler ABI info - done
# | -- Check for working CXX compiler: /usr/bin/clang++ - skipped
# | -- Detecting CXX compile features
# | -- Detecting CXX compile features - done
# | -- Detecting C compiler ABI info
# | -- Detecting C compiler ABI info - done
# | -- Check for working C compiler: /usr/bin/clang - skipped
# | -- Detecting C compile features
# | -- Detecting C compile features - done
# | -- Looking for histedit.h
# | -- Looking for histedit.h - found
# | -- Found LibEdit: /usr/include (found version "2.11") 
# | -- Found ZLIB: /usr/lib/x86_64-linux-gnu/libz.so (found version "1.2.11") 
# | -- Found LibXml2: /usr/lib/x86_64-linux-gnu/libxml2.so (found version "2.9.13") 
# | -- Using MLIRConfig.cmake in: /build/buildbot/premerge-monolithic-linux/build/lib/cmake/mlir
# | -- Using LLVMConfig.cmake in: /build/buildbot/premerge-monolithic-linux/build/lib/cmake/llvm
# | -- Linker detection: unknown
# | -- Performing Test LLVM_LIBSTDCXX_MIN
# | -- Performing Test LLVM_LIBSTDCXX_MIN - Success
# | -- Performing Test LLVM_LIBSTDCXX_SOFT_ERROR
# | -- Performing Test LLVM_LIBSTDCXX_SOFT_ERROR - Success
# | -- Performing Test CXX_SUPPORTS_CUSTOM_LINKER
# | -- Performing Test CXX_SUPPORTS_CUSTOM_LINKER - Success
# | -- Performing Test C_SUPPORTS_FPIC
# | -- Performing Test C_SUPPORTS_FPIC - Success
# | -- Performing Test CXX_SUPPORTS_FPIC

[pcc]

clang-cl /c compiler-rt/lib/builtins/aarch64/emupac.cpp /I third-party/siphash/include --target=aarch64-pc-win32 /O2 compiles here, so I'd expect this exclusion to be for cl.exe only.

[zacklj89]

My mistake @pcc, I thought the __asm__ and register language extensions didn't work on clang-cl as well. I'll open a follow up.

[zacklj89]

Follow up here: #150108