[compiler-rt] [libcxx] [llvm] compiler-rt: Introduce runtime functions for emulated PAC. (PR #133530)

[Paul Osmialowski via llvm-commits]

pawosm-arm wrote:

Turned my CI red,
```
11:46:21  Testing: 
11:46:21  FAIL: Builtins-aarch64-linux :: aarch64/emupac.c (543 of 93329)
11:46:21  ******************** TEST 'Builtins-aarch64-linux :: aarch64/emupac.c' FAILED ********************
11:46:21  Exit Code: 1
11:46:21  
11:46:21  Command Output (stderr):
11:46:21  --
11:46:21  /workspace/build/stage/product_build/./bin/clang   -gline-tables-only   -Wthread-safety -Wthread-safety-reference -Wthread-safety-beta  -DCOMPILER_RT_HAS_FLOAT16  -fno-builtin -I /workspace/src/compiler-rt/lib/builtins -nodefaultlibs /workspace/src/compiler-rt/test/builtins/Unit/aarch64/emupac.c /workspace/build/stage/product_build/./lib/../lib/clang/21/lib/aarch64-unknown-linux-gnu/libclang_rt.builtins.a -lc -lm -o /workspace/build/stage/product_build/runtimes/runtimes-bins/compiler-rt/test/builtins/Unit/AARCH64LinuxConfig/aarch64/Output/emupac.c.tmp # RUN: at line 2
11:46:21  + /workspace/build/stage/product_build/./bin/clang -gline-tables-only -Wthread-safety -Wthread-safety-reference -Wthread-safety-beta -DCOMPILER_RT_HAS_FLOAT16 -fno-builtin -I /workspace/src/compiler-rt/lib/builtins -nodefaultlibs /workspace/src/compiler-rt/test/builtins/Unit/aarch64/emupac.c /workspace/build/stage/product_build/./lib/../lib/clang/21/lib/aarch64-unknown-linux-gnu/libclang_rt.builtins.a -lc -lm -o /workspace/build/stage/product_build/runtimes/runtimes-bins/compiler-rt/test/builtins/Unit/AARCH64LinuxConfig/aarch64/Output/emupac.c.tmp
11:46:21  /workspace/build/stage/product_build/runtimes/runtimes-bins/compiler-rt/test/builtins/Unit/AARCH64LinuxConfig/aarch64/Output/emupac.c.tmp 1 # RUN: at line 3
11:46:21  + /workspace/build/stage/product_build/runtimes/runtimes-bins/compiler-rt/test/builtins/Unit/AARCH64LinuxConfig/aarch64/Output/emupac.c.tmp 1
11:46:21  /workspace/build/stage/product_build/runtimes/runtimes-bins/compiler-rt/test/builtins/Unit/AARCH64LinuxConfig/aarch64/Output/emupac.c.tmp 2 # RUN: at line 4
11:46:21  + /workspace/build/stage/product_build/runtimes/runtimes-bins/compiler-rt/test/builtins/Unit/AARCH64LinuxConfig/aarch64/Output/emupac.c.tmp 2
11:46:21  not --crash  /workspace/build/stage/product_build/runtimes/runtimes-bins/compiler-rt/test/builtins/Unit/AARCH64LinuxConfig/aarch64/Output/emupac.c.tmp 3 # RUN: at line 5
11:46:21  + not --crash /workspace/build/stage/product_build/runtimes/runtimes-bins/compiler-rt/test/builtins/Unit/AARCH64LinuxConfig/aarch64/Output/emupac.c.tmp 3
```
should a revert be considered?

https://github.com/llvm/llvm-project/pull/133530