[clang] [Clang][RISCV] Support -fcf-protection=return for RISC-V (PR #112477)

[Ming-Yi Lai via cfe-commits]

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@@ -899,6 +899,10 @@ void CodeGenFunction::StartFunction(GlobalDecl GD, QualType RetTy,
   if (CodeGenOpts.PointerAuth.IndirectGotos)
     Fn->addFnAttr("ptrauth-indirect-gotos");
 
+  // Add return control flow integrity attributes.
+  if (CodeGenOpts.CFProtectionReturn)
+    Fn->addFnAttr("hw-shadow-stack");
+
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mylai-mtk wrote:

This feel a bit weird: I thought using `-fcf-protection=return` to select hardware-based shadow stack is a RISC-V specific thing. Perhaps for now this should look more tailored for RISC-V to avoid misleading?

https://github.com/llvm/llvm-project/pull/112477