[Clang][AArch64] Add ACLE macros for FEAT_PAuth_LR (#80163)

This updates clang's target defines to include the ACLE changes covering
the FEAT_PAuth_LR architecture extension.
The changes include:
* The new `__ARM_FEATURE_PAUTH_LR` feature macro, which is set to 1 when
  FEAT_PAuth_LR is available in the target.
* A new bit field for the existing `__ARM_FEATURE_PAC_DEFAULT` macro,
  indicating the use of PC as a diversifier for Pointer Authentication
  (from -mbranch-protection=pac-ret+pc).

The approved changes to the ACLE spec can be found here:
https://github.com/ARM-software/acle/pull/292

3 files changed, 43 insertions, 0 deletions

diff --git a/clang/lib/Basic/Targets/AArch64.cpp b/clang/lib/Basic/Targets/AArch64.cpp
index c89e16677e97..46f14b47261a 100644
--- a/clang/lib/Basic/Targets/AArch64.cpp
+++ b/clang/lib/Basic/Targets/AArch64.cpp
@@ -466,6 +466,9 @@ void AArch64TargetInfo::getTargetDefines(const LangOptions &Opts,
   if (HasPAuth)
     Builder.defineMacro("__ARM_FEATURE_PAUTH", "1");
 
+  if (HasPAuthLR)
+    Builder.defineMacro("__ARM_FEATURE_PAUTH_LR", "1");
+
   if (HasUnaligned)
     Builder.defineMacro("__ARM_FEATURE_UNALIGNED", "1");
 
@@ -517,6 +520,7 @@ void AArch64TargetInfo::getTargetDefines(const LangOptions &Opts,
     // 0: Protection using the A key
     // 1: Protection using the B key
     // 2: Protection including leaf functions
+    // 3: Protection using PC as a diversifier
     unsigned Value = 0;
 
     if (Opts.isSignReturnAddressWithAKey())
@@ -527,6 +531,9 @@ void AArch64TargetInfo::getTargetDefines(const LangOptions &Opts,
     if (Opts.isSignReturnAddressScopeAll())
       Value |= (1 << 2);
 
+    if (Opts.BranchProtectionPAuthLR)
+      Value |= (1 << 3);
+
     Builder.defineMacro("__ARM_FEATURE_PAC_DEFAULT", std::to_string(Value));
   }
 
@@ -966,6 +973,10 @@ bool AArch64TargetInfo::handleTargetFeatures(std::vector<std::string> &Features,
       HasGCS = true;
     if (Feature == "+rcpc3")
       HasRCPC3 = true;
+    if (Feature == "+pauth-lr") {
+      HasPAuthLR = true;
+      HasPAuth = true;
+    }
   }
 
   // Check features that are manually disabled by command line options.
diff --git a/clang/lib/Basic/Targets/AArch64.h b/clang/lib/Basic/Targets/AArch64.h
index 9f5e88a6ddd9..7761812295ff 100644
--- a/clang/lib/Basic/Targets/AArch64.h
+++ b/clang/lib/Basic/Targets/AArch64.h
@@ -84,6 +84,7 @@ class LLVM_LIBRARY_VISIBILITY AArch64TargetInfo : public TargetInfo {
   bool HasGCS = false;
   bool HasRCPC3 = false;
   bool HasSMEFA64 = false;
+  bool HasPAuthLR = false;
 
   const llvm::AArch64::ArchInfo *ArchInfo = &llvm::AArch64::ARMV8A;
 
diff --git a/clang/test/Preprocessor/aarch64-target-features.c b/clang/test/Preprocessor/aarch64-target-features.c
index 15879da04fcf..062b802909f1 100644
--- a/clang/test/Preprocessor/aarch64-target-features.c
+++ b/clang/test/Preprocessor/aarch64-target-features.c
@@ -602,6 +602,37 @@
 // CHECK-GCS-DEFAULT: __ARM_FEATURE_GCS_DEFAULT 1
 // CHECK-NOGCS-DEFAULT-NOT: __ARM_FEATURE_GCS_DEFAULT 1
 
+// ================== Check Armv9.5-A Pointer Authentication Enhancements(PAuth_LR).
+// RUN: %clang -target arm64-none-linux-gnu -march=armv8-a -x c -E -dM %s -o - | FileCheck -check-prefix=CHECK-PAUTH-LR-OFF %s
+// RUN: %clang -target arm64-none-linux-gnu -march=armv9.5-a -x c -E -dM %s -o - | FileCheck -check-prefix=CHECK-PAUTH-LR-OFF %s
+// RUN: %clang -target arm64-none-linux-gnu -march=armv8-a+pauth -mbranch-protection=none -x c -E -dM %s -o - | FileCheck -check-prefix=CHECK-PAUTH-LR-OFF %s
+// RUN: %clang -target arm64-none-linux-gnu -march=armv8-a+pauth-lr -mbranch-protection=none -x c -E -dM %s -o - | FileCheck -check-prefix=CHECK-PAUTH-LR %s
+// RUN: %clang -target arm64-none-linux-gnu -march=armv8-a+pauth-lr -mbranch-protection=bti -x c -E -dM %s -o - | FileCheck -check-prefix=CHECK-PAUTH-LR %s
+// RUN: %clang -target arm64-none-linux-gnu -march=armv8-a -mbranch-protection=standard -x c -E -dM %s -o - | FileCheck -check-prefix=CHECK-PAUTH-LR-OFF %s
+// RUN: %clang -target arm64-none-linux-gnu -march=armv8-a -mbranch-protection=pac-ret -x c -E -dM %s -o - | FileCheck -check-prefix=CHECK-PAUTH-LR-OFF %s
+// RUN: %clang -target arm64-none-linux-gnu -march=armv8-a -mbranch-protection=pac-ret+b-key -x c -E -dM %s -o - | FileCheck -check-prefix=CHECK-PAUTH-LR-OFF %s
+// RUN: %clang -target arm64-none-linux-gnu -march=armv8-a -mbranch-protection=pac-ret+leaf -x c -E -dM %s -o - | FileCheck -check-prefix=CHECK-PAUTH-LR-OFF %s
+// RUN: %clang -target arm64-none-linux-gnu -march=armv8-a -mbranch-protection=pac-ret+leaf+b-key -x c -E -dM %s -o - | FileCheck -check-prefix=CHECK-PAUTH-LR-OFF %s
+// RUN: %clang -target arm64-none-linux-gnu -march=armv8-a+pauth-lr -mbranch-protection=pac-ret -x c -E -dM %s -o - | FileCheck -check-prefix=CHECK-PAUTH-LR %s
+// RUN: %clang -target arm64-none-linux-gnu -march=armv8-a+pauth-lr -mbranch-protection=pac-ret+b-key -x c -E -dM %s -o - | FileCheck -check-prefix=CHECK-PAUTH-LR %s
+// RUN: %clang -target arm64-none-linux-gnu -march=armv8-a+pauth-lr -mbranch-protection=pac-ret+leaf -x c -E -dM %s -o - | FileCheck -check-prefix=CHECK-PAUTH-LR %s
+// RUN: %clang -target arm64-none-linux-gnu -march=armv8-a+pauth-lr -mbranch-protection=pac-ret+leaf+b-key -x c -E -dM %s -o - | FileCheck -check-prefix=CHECK-PAUTH-LR %s
+// RUN: %clang -target arm64-none-linux-gnu -march=armv8-a -mbranch-protection=pac-ret+pc -x c -E -dM %s -o - | FileCheck -check-prefixes=CHECK-PAUTH-LR-OFF,CHECK-BRANCH-PROTECTION-PC %s
+// RUN: %clang -target arm64-none-linux-gnu -march=armv8-a -mbranch-protection=pac-ret+pc+b-key -x c -E -dM %s -o - | FileCheck -check-prefixes=CHECK-PAUTH-LR-OFF,CHECK-BRANCH-PROTECTION-PC-BKEY %s
+// RUN: %clang -target arm64-none-linux-gnu -march=armv8-a -mbranch-protection=pac-ret+pc+leaf -x c -E -dM %s -o - | FileCheck -check-prefixes=CHECK-PAUTH-LR-OFF,CHECK-BRANCH-PROTECTION-PC-LEAF %s
+// RUN: %clang -target arm64-none-linux-gnu -march=armv8-a -mbranch-protection=pac-ret+pc+leaf+b-key -x c -E -dM %s -o - | FileCheck -check-prefixes=CHECK-PAUTH-LR-OFF,CHECK-BRANCH-PROTECTION-PC-LEAF-BKEY %s
+// RUN: %clang -target arm64-none-linux-gnu -march=armv8-a+pauth-lr -mbranch-protection=pac-ret+pc -x c -E -dM %s -o - | FileCheck -check-prefixes=CHECK-PAUTH-LR,CHECK-BRANCH-PROTECTION-PC %s
+// RUN: %clang -target arm64-none-linux-gnu -march=armv8-a+pauth-lr -mbranch-protection=pac-ret+pc+b-key -x c -E -dM %s -o - | FileCheck -check-prefixes=CHECK-PAUTH-LR,CHECK-BRANCH-PROTECTION-PC-BKEY %s
+// RUN: %clang -target arm64-none-linux-gnu -march=armv8-a+pauth-lr -mbranch-protection=pac-ret+pc+leaf -x c -E -dM %s -o - | FileCheck -check-prefixes=CHECK-PAUTH-LR,CHECK-BRANCH-PROTECTION-PC-LEAF %s
+// RUN: %clang -target arm64-none-linux-gnu -march=armv8-a+pauth-lr -mbranch-protection=pac-ret+pc+leaf+b-key -x c -E -dM %s -o - | FileCheck -check-prefixes=CHECK-PAUTH-LR,CHECK-BRANCH-PROTECTION-PC-LEAF-BKEY %s
+// CHECK-BRANCH-PROTECTION-PC:           #define __ARM_FEATURE_PAC_DEFAULT 9
+// CHECK-BRANCH-PROTECTION-PC-BKEY:      #define __ARM_FEATURE_PAC_DEFAULT 10
+// CHECK-BRANCH-PROTECTION-PC-LEAF:      #define __ARM_FEATURE_PAC_DEFAULT 13
+// CHECK-BRANCH-PROTECTION-PC-LEAF-BKEY: #define __ARM_FEATURE_PAC_DEFAULT 14
+// CHECK-PAUTH-LR-OFF-NOT: #define __ARM_FEATURE_PAUTH_LR 1
+// CHECK-PAUTH-LR:         #define __ARM_FEATURE_PAUTH 1
+// CHECK-PAUTH-LR:         #define __ARM_FEATURE_PAUTH_LR 1
+
 // ================== Check default macros for Armv8.1-A and later
 // RUN: %clang -target aarch64-none-elf -march=armv8.1-a -x c -E -dM %s -o - | FileCheck --check-prefixes=CHECK-V81-OR-LATER,CHECK-BEFORE-V83,CHECK-BEFORE-V85     %s
 // RUN: %clang -target aarch64-none-elf -march=armv8.2-a -x c -E -dM %s -o - | FileCheck --check-prefixes=CHECK-V81-OR-LATER,CHECK-BEFORE-V83,CHECK-BEFORE-V85     %s