[Driver] Add -mbranch-protection to ARM and AArch64 multilib flags

[pratlucas]

This adds the -mbranch-protection command line option to the set of
flags used by the multilib selection for ARM and AArch64 targets.

[llvmbot]

@llvm/pr-subscribers-clang

@llvm/pr-subscribers-clang-driver

Author: Lucas Duarte Prates (pratlucas)

Changes

This adds the -mbranch-protection command line option to the set of
flags used by the multilib selection for ARM and AArch64 targets.

---

Full diff: https://github.com/llvm/llvm-project/pull/106391.diff

2 Files Affected:

• (modified) clang/lib/Driver/ToolChain.cpp (+10)
• (modified) clang/test/Driver/print-multi-selection-flags.c (+4)

diff --git a/clang/lib/Driver/ToolChain.cpp b/clang/lib/Driver/ToolChain.cpp
index c93c97146b6104..442512366c9114 100644
--- a/clang/lib/Driver/ToolChain.cpp
+++ b/clang/lib/Driver/ToolChain.cpp
@@ -221,6 +221,11 @@ static void getAArch64MultilibFlags(const Driver &D,
   assert(!ArchName.empty() && "at least one architecture should be found");
   MArch.insert(MArch.begin(), ("-march=" + ArchName).str());
   Result.push_back(llvm::join(MArch, "+"));
+
+  const Arg *BranchProtectionArg = Args.getLastArgNoClaim(options::OPT_mbranch_protection_EQ);
+  if (BranchProtectionArg) {
+    Result.push_back(BranchProtectionArg->getAsString(Args));
+  }
 }
 
 static void getARMMultilibFlags(const Driver &D,
@@ -268,6 +273,11 @@ static void getARMMultilibFlags(const Driver &D,
   case arm::FloatABI::Invalid:
     llvm_unreachable("Invalid float ABI");
   }
+
+  const Arg *BranchProtectionArg = Args.getLastArgNoClaim(options::OPT_mbranch_protection_EQ);
+  if (BranchProtectionArg) {
+    Result.push_back(BranchProtectionArg->getAsString(Args));
+  }
 }
 
 static void getRISCVMultilibFlags(const Driver &D, const llvm::Triple &Triple,
diff --git a/clang/test/Driver/print-multi-selection-flags.c b/clang/test/Driver/print-multi-selection-flags.c
index 2770a3ad5eaa1d..0116c7f5a03b9a 100644
--- a/clang/test/Driver/print-multi-selection-flags.c
+++ b/clang/test/Driver/print-multi-selection-flags.c
@@ -59,6 +59,10 @@
 // CHECK-SVE2: --target=aarch64-unknown-none-elf
 // CHECK-SVE2: -march=armv{{.*}}-a{{.*}}+simd{{.*}}+sve{{.*}}+sve2{{.*}}
 
+// RUN: %clang -print-multi-flags-experimental --target=arm-none-eabi -mbranch-protection=standard    | FileCheck --check-prefix=CHECK-BRANCH-PROTECTION %s
+// RUN: %clang -print-multi-flags-experimental --target=aarch64-none-elf -mbranch-protection=standard | FileCheck --check-prefix=CHECK-BRANCH-PROTECTION %s
+// CHECK-BRANCH-PROTECTION: -mbranch-protection=standard
+
 // RUN: %clang -print-multi-flags-experimental --target=riscv32-none-elf -march=rv32g | FileCheck --check-prefix=CHECK-RV32 %s
 // CHECK-RV32: --target=riscv32-unknown-none-elf
 // CHECK-RV32: -mabi=ilp32d

[github-actions]

✅ With the latest revision this PR passed the C/C++ code formatter.

[ostannard]

LGTM