[Clang][AArch64] Implement ACLE feature macro for FEAT_LRCPC3

[pratlucas]

Summary

This implements the new value for the __ARM_FEATURE_RCPC feature
macro, which was introduced to the ACLE to indicate the availability of
FEAT_LRCPC3.

More details can be found on:
https://github.com/ARM-software/acle/blob/main/main/acle.md#rcpc

[tmatheson]

LGTM

clang/lib/Basic/Targets/AArch64.cpp

420

I didn't realise we hadn't implemented RPCP2 here. If we aren't aware of anyone

clang/lib/Basic/Targets/AArch64.h

class LLVM_LIBRARY_VISIBILITY AArch64TargetInfo : public TargetInfo {
   bool HasWFxT = false;
   bool HasJSCVT = false;
   bool HasFCMA = false;
   bool HasNoFP = false;
   bool HasNoNeon = false;
   bool HasNoSVE = false;
   bool HasFMV = true;
   bool HasGCS = false;
+  bool HasRCPC3 = false;
 
   const llvm::AArch64::ArchInfo *ArchInfo = &llvm::AArch64::ARMV8A;
 
   std::string ABI;
 
 public:
   AArch64TargetInfo(const llvm::Triple &Triple, const TargetOptions &Opts);
 

clang/lib/Basic/Targets/AArch64.cpp

if (HasSVE2 && HasSVE2SHA3)
     Builder.defineMacro("__ARM_FEATURE_SVE2_SHA3", "1");
 
   if (HasSVE2 && HasSVE2SM4)
     Builder.defineMacro("__ARM_FEATURE_SVE2_SM4", "1");
 
   if (HasCRC)
     Builder.defineMacro("__ARM_FEATURE_CRC32", "1");
 
-  if (HasRCPC)
+  if (HasRCPC3)
+    Builder.defineMacro("__ARM_FEATURE_RCPC", "3");
+  else if (HasRCPC)
     Builder.defineMacro("__ARM_FEATURE_RCPC", "1");
 
   if (HasFMV)
     Builder.defineMacro("__HAVE_FUNCTION_MULTI_VERSIONING", "1");
 
   // The __ARM_FEATURE_CRYPTO is deprecated in favor of finer grained feature
   // macros for AES, SHA2, SHA3 and SM4
   if (HasAES && HasSHA2)
return llvm::StringSwitch<bool>(Feature)
       .Case("sme-i16i64", HasSMEI16I64)
       .Cases("memtag", "memtag2", HasMTE)
       .Case("sb", HasSB)
       .Case("predres", HasPredRes)
       .Cases("ssbs", "ssbs2", HasSSBS)
       .Case("bti", HasBTI)
       .Cases("ls64", "ls64_v", "ls64_accdata", HasLS64)
       .Case("wfxt", HasWFxT)
+      .Case("rcpc3", HasRCPC3)
       .Default(false);
 }
 
 void AArch64TargetInfo::setFeatureEnabled(llvm::StringMap<bool> &Features,
                                           StringRef Name, bool Enabled) const {
   Features[Name] = Enabled;
   // If the feature is an architecture feature (like v8.2a), add all previous
   // architecture versions and any dependant target features.
if (Feature == "+altnzcv") {
       HasAlternativeNZCV = true;
     }
     if (Feature == "+mops")
       HasMOPS = true;
     if (Feature == "+d128")
       HasD128 = true;
     if (Feature == "+gcs")
       HasGCS = true;
+    if (Feature == "+rcpc3")
+      HasRCPC3 = true;
   }
 
   // Check features that are manually disabled by command line options.
   // This needs to be checked after architecture-related features are handled,
   // making sure they are properly disabled when required.
   for (const auto &Feature : Features) {
     if (Feature == "-d128")
       HasD128 = false;

clang/test/Preprocessor/aarch64-target-features.c

 // CHECK-NOT: __ARM_FEATURE_CRYPTO 1
 // CHECK: __ARM_FEATURE_DIRECTED_ROUNDING 1
 // CHECK: __ARM_FEATURE_DIV 1
 // CHECK: __ARM_FEATURE_FMA 1
 // CHECK: __ARM_FEATURE_IDIV 1
 // CHECK: __ARM_FEATURE_LDREX 0xF
 // CHECK: __ARM_FEATURE_NUMERIC_MAXMIN 1
 // CHECK-NOT: __ARM_FEATURE_RCPC 1
+// CHECK-NOT: __ARM_FEATURE_RCPC 3
 // CHECK-NOT: __ARM_FEATURE_SHA2 1
 // CHECK-NOT: __ARM_FEATURE_SHA3 1
 // CHECK-NOT: __ARM_FEATURE_SHA512 1
 // CHECK-NOT: __ARM_FEATURE_SM3 1
 // CHECK-NOT: __ARM_FEATURE_SM4 1
 // CHECK: __ARM_FEATURE_UNALIGNED 1
 // CHECK: __ARM_FP 0xE
 // CHECK: __ARM_FP16_ARGS 1

 // CHECK-V83-OR-LATER: __ARM_FEATURE_PAUTH 1
 // CHECK-V81-OR-LATER: __ARM_FEATURE_QRDMX 1
 // CHECK-BEFORE-V83-NOT: __ARM_FEATURE_COMPLEX 1
 // CHECK-BEFORE-V83-NOT: __ARM_FEATURE_JCVT 1
 // CHECK-BEFORE-V85-NOT: __ARM_FEATURE_FRINT 1
 
 // RUN: %clang --target=aarch64 -march=armv8.2-a+rcpc -x c -E -dM %s -o - | FileCheck --check-prefix=CHECK-RCPC %s
 // CHECK-RCPC: __ARM_FEATURE_RCPC 1
+
+// RUN: %clang --target=aarch64 -march=armv8.2-a+rcpc3 -x c -E -dM %s -o - | FileCheck --check-prefix=CHECK-RCPC3 %s
+// CHECK-RCPC3: __ARM_FEATURE_RCPC 3