Use std::bitset for SubtargetFeatures

Previously, subtarget features were a bitfield with the underlying type being uint64_t. 
Since several targets (X86 and ARM, in particular) have hit or were very close to hitting this bound, switching the features to use a bitset.
No functional change.

The first time this was committed (r229831), it caused several buildbot failures. 
At least some of the ARM ones were due to gcc/binutils issues, and should now be fixed.

Differential Revision: http://reviews.llvm.org/D8542

llvm-svn: 233055

1 files changed, 6 insertions, 4 deletions

diff --git a/llvm/lib/Target/AArch64/Utils/AArch64BaseInfo.h b/llvm/lib/Target/AArch64/Utils/AArch64BaseInfo.h
index 6d0337ce15e..4e80a79d293 100644
--- a/llvm/lib/Target/AArch64/Utils/AArch64BaseInfo.h
+++ b/llvm/lib/Target/AArch64/Utils/AArch64BaseInfo.h
@@ -26,6 +26,8 @@
 
 namespace llvm {
 
+class FeatureBitset;
+
 inline static unsigned getWRegFromXReg(unsigned Reg) {
   switch (Reg) {
   case AArch64::X0: return AArch64::W0;
@@ -1139,21 +1141,21 @@ namespace AArch64SysReg {
 
     const AArch64NamedImmMapper::Mapping *InstPairs;
     size_t NumInstPairs;
-    uint64_t FeatureBits;
+    const FeatureBitset &FeatureBits;
 
-    SysRegMapper(uint64_t FeatureBits) : FeatureBits(FeatureBits) { }
+    SysRegMapper(const FeatureBitset &FeatureBits) : FeatureBits(FeatureBits) { }
     uint32_t fromString(StringRef Name, bool &Valid) const;
     std::string toString(uint32_t Bits) const;
   };
 
   struct MSRMapper : SysRegMapper {
     static const AArch64NamedImmMapper::Mapping MSRPairs[];
-    MSRMapper(uint64_t FeatureBits);
+    MSRMapper(const FeatureBitset &FeatureBits);
   };
 
   struct MRSMapper : SysRegMapper {
     static const AArch64NamedImmMapper::Mapping MRSPairs[];
-    MRSMapper(uint64_t FeatureBits);
+    MRSMapper(const FeatureBitset &FeatureBits);
   };
 
   uint32_t ParseGenericRegister(StringRef Name, bool &Valid);