[AArch64] Remove unused feature flags from AArch64TargetInfo

[tyb0807]

Summary

This removes two feature flags from AArch64TargetInfo class:

• HasHBC: this feature does not involve generating any IR intrinsics,

so clang does not need to know about whether it is set

• HasCrypto: this feature is deprecated in favor of finer grained

features such as AES, SHA2, SHA3 and SM4

[CarolineConcatto]

Just passing by, but I was wondering when I saw this patch.
Why you did not remove this also from lib/Driver/ToolChains/Arch/AArch64.cpp?
And the ones in llvm (AArch64.td, AArch64InstrInfo.td)?

[tyb0807]

TL;DR, I think these Has* flags have different meaning in different places of the code base.

IIUC, these Has* flags from clang/lib/Basic/Targets/AArch64.cpp are used to correctly set various macros from the processed command line options, notable ones from ACLE, whereas the Has* flags from lib/Driver/ToolChains/Arch/AArch64.cpp are used to set the target features CL options.

As for the ones in llvm, the original flags are from AArch64Subtarget flag, and they are used to describe the architecture features, used in various places in the back-end itself.

[tyb0807]

Remove reference to unused ACLE macro __ARM_FEATURE_CRYPTO

[tyb0807]

Revert latest change, as it is likely that people still rely on __ARM_FEATURE_CRYPTO

[vhscampos]

LGTM

clang/lib/Basic/Targets/AArch64.h

class LLVM_LIBRARY_VISIBILITY AArch64TargetInfo : public TargetInfo {
   virtual void setDataLayout() = 0;
   static const TargetInfo::GCCRegAlias GCCRegAliases[];
   static const char *const GCCRegNames[];
 
   enum FPUModeEnum { FPUMode, NeonMode = (1 << 0), SveMode = (1 << 1) };
 
   unsigned FPU;
   bool HasCRC;
-  bool HasCrypto;
   bool HasAES;
   bool HasSHA2;
   bool HasSHA3;
   bool HasSM4;
   bool HasUnaligned;
   bool HasFullFP16;
   bool HasDotProd;
   bool HasFP16FML;
   bool HasMTE;
   bool HasTME;
   bool HasPAuth;
   bool HasLS64;
   bool HasRandGen;
   bool HasMatMul;
   bool HasSVE2;
   bool HasSVE2AES;
   bool HasSVE2SHA3;
   bool HasSVE2SM4;
   bool HasSVE2BitPerm;
   bool HasMatmulFP64;
   bool HasMatmulFP32;
   bool HasLSE;
   bool HasFlagM;
-  bool HasHBC;
   bool HasMOPS;
 
   llvm::AArch64::ArchKind ArchKind;
 
   static const Builtin::Info BuiltinInfo[];
 
   std::string ABI;
   StringRef getArchProfile() const;

clang/lib/Basic/Targets/AArch64.cpp

return Feature == "aarch64" || Feature == "arm64" || Feature == "arm" ||
           (FPU & SveMode)) ||
          (Feature == "ls64" && HasLS64);
 }
 
 bool AArch64TargetInfo::handleTargetFeatures(std::vector<std::string> &Features,
                                              DiagnosticsEngine &Diags) {
   FPU = FPUMode;
   HasCRC = false;
-  HasCrypto = false;
   HasAES = false;
   HasSHA2 = false;
   HasSHA3 = false;
   HasSM4 = false;
   HasUnaligned = true;
   HasFullFP16 = false;
   HasDotProd = false;
   HasFP16FML = false;
   HasMTE = false;
   HasTME = false;
   HasLS64 = false;
   HasRandGen = false;
   HasMatMul = false;
   HasBFloat16 = false;
   HasSVE2 = false;
   HasSVE2AES = false;
   HasSVE2SHA3 = false;
   HasSVE2SM4 = false;
   HasSVE2BitPerm = false;
   HasMatmulFP64 = false;
   HasMatmulFP32 = false;
   HasLSE = false;
-  HasHBC = false;
   HasMOPS = false;
 
   ArchKind = llvm::AArch64::ArchKind::INVALID;
 
   for (const auto &Feature : Features) {
     if (Feature == "+neon")
       FPU |= NeonMode;
     if (Feature == "+sve") {
if (Feature == "+f32mm") {
       HasMatmulFP32 = true;
     }
     if (Feature == "+f64mm") {
       FPU |= SveMode;
       HasMatmulFP64 = true;
     }
     if (Feature == "+crc")
       HasCRC = true;
-    if (Feature == "+crypto")
-      HasCrypto = true;
     if (Feature == "+aes")
       HasAES = true;
     if (Feature == "+sha2")
       HasSHA2 = true;
     if (Feature == "+sha3") {
       HasSHA2 = true;
       HasSHA3 = true;
     }
for (const auto &Feature : Features) {
     if (Feature == "+lse")
       HasLSE = true;
     if (Feature == "+ls64")
       HasLS64 = true;
     if (Feature == "+rand")
       HasRandGen = true;
     if (Feature == "+flagm")
       HasFlagM = true;
-    if (Feature == "+hbc")
-      HasHBC = true;
     if (Feature == "+mops")
       HasMOPS = true;
   }
 
   setDataLayout();
 
   return true;
 }