[clang] [Clang][RISCV] Add preprocessor macros for Zicfilp CFI scheme (PR #109600)

[Ming-Yi Lai via cfe-commits]

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@@ -224,6 +225,34 @@ void RISCVTargetInfo::getTargetDefines(const LangOptions &Opts,
     else
       Builder.defineMacro("__riscv_32e");
   }
+
+  if (Opts.CFProtectionBranch) {
+    if (checkCFProtectionBranchSupported()) {
+      auto Scheme = Opts.getCFBranchLabelScheme();
+      if (checkCFBranchLabelSchemeSupported(Scheme)) {
+        if (Scheme == CFBranchLabelSchemeKind::Default)
+          Scheme = getDefaultCFBranchLabelScheme();
+
+        Builder.defineMacro("__riscv_landing_pad", "1");
+        switch (Scheme) {
+        case CFBranchLabelSchemeKind::Unlabeled:
+          Builder.defineMacro("__riscv_landing_pad_unlabeled", "1");
+          break;
+        case CFBranchLabelSchemeKind::FuncSig:
+          Builder.defineMacro("__riscv_landing_pad_func_sig", "1");
+          break;
+        case CFBranchLabelSchemeKind::Default:
+          llvm_unreachable("default cf-branch-label scheme should already be "
+                           "transformed to other scheme");
+        }
+      } else
+        Diags.Report(diag::err_opt_not_valid_on_target)
+            << (Twine("-mcf-branch-label-scheme=") +
+                getCFBranchLabelSchemeFlagVal(Scheme))
+                   .str();
+    } else
+      Diags.Report(diag::err_opt_not_valid_on_target) << "cf-protection=branch";
----------------
mylai-mtk wrote:

Yes, if it's `clang -c` or `clang -S`, I believe it would be diagnosed in `CodeGenModule`, but if it's `clang -E -dM`, it wouldn't be diagnosed, since code gen is not required.

https://github.com/llvm/llvm-project/pull/109600