[clang] [llvm] Add support for Windows hot-patching (PR #138972)

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sivadeilra wrote:

> We already have /HOTPATCH or rather -fms-hotpatch that does something different

They do something different, but not unrelated.  The "Secure Hot-Patching" feature (the feature I'm working on) still relies on the function prolog using hot-patchable code generation.  So `/HOTPATCH` is also necessary for this, as well as the `/FUNCTIONPADMIN` linker option.

I agree that the terminology is a bit confusing, here, since "hot-patching" is a more general concept than the particular feature / workflow that I am working on, and there are many different implementations of the general idea of "hot-patching".  I can certainly add more explanatory text to `WindowsHotPatch.cpp` file.

What would you think of renaming the options to `-fms-secure-hotpatch-functions-file` and `-fms-secure-hotpatch-functions-list`?  The feature internally is known as "Secure Hot-Patching" (SHP), so that aligns with our terminology.  The "secure" word also hints to users that this is not related to dev productivity (such as Edit-and-Continue scenarios).


https://github.com/llvm/llvm-project/pull/138972