[clang][RISCV] Add Zicfilp CFI scheme preprocessor macros

These macros allow assembly files to know which CFI label to use when the target
has Zicfilp enabled.

Author: mylai-mtk

clang/lib/Basic/Targets/RISCV.cpp

@@ -224,6 +224,26 @@ void RISCVTargetInfo::getTargetDefines(const LangOptions &Opts,
     else
       Builder.defineMacro("__riscv_32e");
   }
+
+  if (ISAInfo->hasExtension("zicfilp") && Opts.CFProtectionBranch) {
+    auto Scheme = Opts.getCFBranchLabelScheme();
+    if (Scheme == CFBranchLabelSchemeKind::Default)
+      Scheme = getDefaultCFBranchLabelScheme();
+
+    switch (Scheme) {
+    case CFBranchLabelSchemeKind::Unlabeled:
+      Builder.defineMacro("__riscv_landing_pad", "1");
+      Builder.defineMacro("__riscv_landing_pad_unlabeled", "1");
+      break;
+    case CFBranchLabelSchemeKind::Default:
+      llvm_unreachable("default cf-branch-label scheme should already be "
+                       "transformed to other scheme");
+    case CFBranchLabelSchemeKind::FuncSig:
+      Builder.defineMacro("__riscv_landing_pad", "1");
+      Builder.defineMacro("__riscv_landing_pad_func_sig", "1");
+      break;
+    }
+  }
 }
 
 static constexpr Builtin::Info BuiltinInfo[] = {

clang/test/Preprocessor/riscv-target-features.c

@@ -1781,3 +1781,35 @@
 // RUN: %clang --target=riscv64-unknown-linux-gnu -mcpu=sifive-p450 -E -dM %s \
 // RUN:  -o - | FileCheck %s --check-prefix=CHECK-MISALIGNED-FAST
 // CHECK-MISALIGNED-FAST: __riscv_misaligned_fast 1
+
+// Landing Pad
+
+// RUN: %clang --target=riscv32 -menable-experimental-extensions \
+// RUN:   -march=rv32i_zicfilp1p0 -fcf-protection=branch \
+// RUN:   -fcf-branch-label-scheme=unlabeled -E -dM %s -o - \
+// RUN:   | FileCheck --check-prefix=CHECK-ZICFILP-UNLABELED %s
+// RUN: %clang --target=riscv64 -menable-experimental-extensions \
+// RUN:   -march=rv64i_zicfilp1p0 -fcf-protection=branch \
+// RUN:   -fcf-branch-label-scheme=unlabeled -E -dM %s -o - \
+// RUN:   | FileCheck --check-prefix=CHECK-ZICFILP-UNLABELED %s
+// CHECK-ZICFILP-UNLABELED-DAG: __riscv_landing_pad 1{{$}}
+// CHECK-ZICFILP-UNLABELED-DAG: __riscv_landing_pad_unlabeled 1{{$}}
+
+// Default cf-branch-label-scheme is func-sig
+// RUN: %clang --target=riscv32 -menable-experimental-extensions \
+// RUN:   -march=rv32i_zicfilp1p0 -fcf-protection=branch -E -dM %s -o - \
+// RUN:   | FileCheck --check-prefix=CHECK-ZICFILP-FUNC-SIG %s
+// RUN: %clang --target=riscv64 -menable-experimental-extensions \
+// RUN:   -march=rv64i_zicfilp1p0 -fcf-protection=branch -E -dM %s -o - \
+// RUN:   | FileCheck --check-prefix=CHECK-ZICFILP-FUNC-SIG %s
+
+// RUN: %clang --target=riscv32 -menable-experimental-extensions \
+// RUN:   -march=rv32i_zicfilp1p0 -fcf-protection=branch \
+// RUN:   -fcf-branch-label-scheme=func-sig -E -dM %s -o - \
+// RUN:   | FileCheck --check-prefix=CHECK-ZICFILP-FUNC-SIG %s
+// RUN: %clang --target=riscv64 -menable-experimental-extensions \
+// RUN:   -march=rv64i_zicfilp1p0 -fcf-protection=branch \
+// RUN:   -fcf-branch-label-scheme=func-sig -E -dM %s -o - \
+// RUN:   | FileCheck --check-prefix=CHECK-ZICFILP-FUNC-SIG %s
+// CHECK-ZICFILP-FUNC-SIG-DAG: __riscv_landing_pad 1{{$}}
+// CHECK-ZICFILP-FUNC-SIG-DAG: __riscv_landing_pad_func_sig 1{{$}}