[UBSan] Runtime Executable Only violation hit when checking the function pointer on an execute-only target.

[MaggieYingYi]

An execute-only target disallows data access to code sections.

The commit rG279a4d causes the generated code to read text section data which is not allowed on an execute-only target.

When enabling the function sanitizer (-fsanitize=function), UBSan function signatures and type hashes are emitted within the function's prologue data to check the function type. This results in the non-execute access and a runtime error.

[llvmbot]

@llvm/issue-subscribers-clang-driver

[llvmbot]

@llvm/issue-subscribers-clang-frontend

[MaggieYingYi]

D158614 is created for code review.

[MaskRay]

/cherry-pick 9ef536a

[llvmbot]

/branch llvm/llvm-project-release-prs/issue64931