[clang] [llvm] riscv: Support -mstack-protector-guard=tls (PR #108942)

[Keith Packard via cfe-commits]

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@@ -3644,13 +3645,28 @@ static void RenderSSPOptions(const Driver &D, const ToolChain &TC,
           << A->getOption().getName() << Value << "sysreg global";
       return;
     }
+    if (EffectiveTriple.isRISCV()) {
+      if (Value != "tls" && Value != "global") {
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keith-packard wrote:

Yeah, I went for the easiest-to-review mechanism that just created new RISC-V specific clauses instead of attempting to mix them into the existing ones. It's not exactly a performance-critical area of code.

https://github.com/llvm/llvm-project/pull/108942