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

[Keith Packard via llvm-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:

Added a test to make sure -mstack-protector-guard=global still works correctly after the patch. Also added positive tests to make sure valid driver arguments get passed through to the backend.

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