[X86] adding pku feature flag

[AsafBadouh]

Summary

the feature flag is essential for RDPKRU and WRPKRU instruction
more about the instruction can be found in the SDM rev 56, vol 2 from http://www.intel.com/sdm

[delena]

LGTM

../trunk/lib/Support/Host.cpp

bool sys::getHostCPUFeatures(StringMap<bool> &Features) {
   Features["fsgsbase"] = HasLeaf7 && ((EBX >>  0) & 1);
   Features["bmi"]      = HasLeaf7 && ((EBX >>  3) & 1);
   Features["hle"]      = HasLeaf7 && ((EBX >>  4) & 1);
   Features["bmi2"]     = HasLeaf7 && ((EBX >>  8) & 1);
   Features["rtm"]      = HasLeaf7 && ((EBX >> 11) & 1);
   Features["rdseed"]   = HasLeaf7 && ((EBX >> 18) & 1);
   Features["adx"]      = HasLeaf7 && ((EBX >> 19) & 1);
   Features["sha"]      = HasLeaf7 && ((EBX >> 29) & 1);
+  // Enable protection keys
+  Features["pku"]    = HasLeaf7 && ((ECX >> 4) & 1);
 
   // AVX512 is only supported if the OS supports the context save for it.
   Features["avx512f"]  = HasLeaf7 && ((EBX >> 16) & 1) && HasAVX512Save;
   Features["avx512dq"] = HasLeaf7 && ((EBX >> 17) & 1) && HasAVX512Save;
   Features["avx512pf"] = HasLeaf7 && ((EBX >> 26) & 1) && HasAVX512Save;
   Features["avx512er"] = HasLeaf7 && ((EBX >> 27) & 1) && HasAVX512Save;
   Features["avx512cd"] = HasLeaf7 && ((EBX >> 28) & 1) && HasAVX512Save;
   Features["avx512bw"] = HasLeaf7 && ((EBX >> 30) & 1) && HasAVX512Save;

../trunk/lib/Target/X86/X86.td

def FeatureDQI     : SubtargetFeature<"avx512dq", "HasDQI", "true",
                       "Enable AVX-512 Doubleword and Quadword Instructions",
                                       [FeatureAVX512]>;
 def FeatureBWI     : SubtargetFeature<"avx512bw", "HasBWI", "true",
                       "Enable AVX-512 Byte and Word Instructions",
                                       [FeatureAVX512]>;
 def FeatureVLX     : SubtargetFeature<"avx512vl", "HasVLX", "true",
                       "Enable AVX-512 Vector Length eXtensions",
                                       [FeatureAVX512]>;
+def FeaturePKU   : SubtargetFeature<"pku", "HasPKU", "true",
+                      "Enable protection keys">;
 def FeaturePCLMUL  : SubtargetFeature<"pclmul", "HasPCLMUL", "true",
                          "Enable packed carry-less multiplication instructions",
                                [FeatureSSE2]>;
 def FeatureFMA     : SubtargetFeature<"fma", "HasFMA", "true",
                                       "Enable three-operand fused multiple-add",
                                       [FeatureAVX]>;
 def FeatureFMA4    : SubtargetFeature<"fma4", "HasFMA4", "true",
                                       "Enable four-operand fused multiple-add",

 class SkylakeProc<string Name> : ProcessorModel<Name, HaswellModel, [
   FeatureMMX,
   FeatureAVX512,
   FeatureFXSR,
   FeatureCDI,
   FeatureDQI,
   FeatureBWI,
   FeatureVLX,
+  FeaturePKU,
   FeatureCMPXCHG16B,
   FeatureSlowBTMem,
   FeaturePOPCNT,
   FeatureAES,
   FeaturePCLMUL,
   FeatureXSAVE,
   FeatureXSAVEOPT,
   FeatureRDRAND,

../trunk/lib/Target/X86/X86InstrInfo.td

 def HasBWI       : Predicate<"Subtarget->hasBWI()">,
                      AssemblerPredicate<"FeatureBWI", "AVX-512 BW ISA">;
 def NoBWI        : Predicate<"!Subtarget->hasBWI()">;
 def HasVLX       : Predicate<"Subtarget->hasVLX()">,
                      AssemblerPredicate<"FeatureVLX", "AVX-512 VL ISA">;
 def NoVLX        : Predicate<"!Subtarget->hasVLX()">;
 def NoVLX_Or_NoBWI : Predicate<"!Subtarget->hasVLX() || !Subtarget->hasBWI()">;
 def NoVLX_Or_NoDQI : Predicate<"!Subtarget->hasVLX() || !Subtarget->hasDQI()">;
+def PKU        : Predicate<"!Subtarget->hasPKU()">;
 
 def HasPOPCNT    : Predicate<"Subtarget->hasPOPCNT()">;
 def HasAES       : Predicate<"Subtarget->hasAES()">;
 def HasFXSR      : Predicate<"Subtarget->hasFXSR()">;
 def HasXSAVE     : Predicate<"Subtarget->hasXSAVE()">;
 def HasXSAVEOPT  : Predicate<"Subtarget->hasXSAVEOPT()">;
 def HasXSAVEC    : Predicate<"Subtarget->hasXSAVEC()">;
 def HasXSAVES    : Predicate<"Subtarget->hasXSAVES()">;

../trunk/lib/Target/X86/X86Subtarget.h

protected:
   bool HasDQI;
 
   /// Processor has AVX-512 Byte and Word instructions
   bool HasBWI;
 
   /// Processor has AVX-512 Vector Length eXtenstions
   bool HasVLX;
 
+  /// Processor has PKU extenstions
+  bool HasPKU;
+
   /// Processot supports MPX - Memory Protection Extensions
   bool HasMPX;
 
   /// Use software floating point for code generation.
   bool UseSoftFloat;
 
   /// The minimum alignment known to hold of the stack frame on
   /// entry to the function and which must be maintained by every function.
public:
   bool slowLEA() const { return SlowLEA; }
   bool slowIncDec() const { return SlowIncDec; }
   bool hasCDI() const { return HasCDI; }
   bool hasPFI() const { return HasPFI; }
   bool hasERI() const { return HasERI; }
   bool hasDQI() const { return HasDQI; }
   bool hasBWI() const { return HasBWI; }
   bool hasVLX() const { return HasVLX; }
+  bool hasPKU() const { return HasPKU; }
   bool hasMPX() const { return HasMPX; }
 
   bool isAtom() const { return X86ProcFamily == IntelAtom; }
   bool isSLM() const { return X86ProcFamily == IntelSLM; }
   bool useSoftFloat() const { return UseSoftFloat; }
 
   const Triple &getTargetTriple() const { return TargetTriple; }
 

../trunk/lib/Target/X86/X86Subtarget.cpp

void X86Subtarget::initializeEnvironment() {
   HasHLE = false;
   HasERI = false;
   HasCDI = false;
   HasPFI = false;
   HasDQI = false;
   HasBWI = false;
   HasVLX = false;
   HasADX = false;
+  HasPKU = false;
   HasSHA = false;
   HasPRFCHW = false;
   HasRDSEED = false;
   HasLAHFSAHF = false;
   HasMPX = false;
   IsBTMemSlow = false;
   IsSHLDSlow = false;
   IsUAMem16Slow = false;