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 several times this was committed (e.g. r229831, r233055), it caused several buildbot failures.
Apparently the reason for most failures was both clang and gcc's inability to deal with large numbers (> 10K) of bitset constructor calls in tablegen-generated initializers of instruction info tables. 
This should now be fixed.

llvm-svn: 238192

1 files changed, 43 insertions, 35 deletions

diff --git a/llvm/lib/Target/ARM/Disassembler/ARMDisassembler.cpp b/llvm/lib/Target/ARM/Disassembler/ARMDisassembler.cpp
index 609fdb11d6b..097ec04e705 100644
--- a/llvm/lib/Target/ARM/Disassembler/ARMDisassembler.cpp
+++ b/llvm/lib/Target/ARM/Disassembler/ARMDisassembler.cpp
@@ -435,7 +435,7 @@ DecodeStatus ARMDisassembler::getInstruction(MCInst &MI, uint64_t &Size,
                                              raw_ostream &CS) const {
   CommentStream = &CS;
 
-  assert(!(STI.getFeatureBits() & ARM::ModeThumb) &&
+  assert(!STI.getFeatureBits()[ARM::ModeThumb] &&
          "Asked to disassemble an ARM instruction but Subtarget is in Thumb "
          "mode!");
 
@@ -700,7 +700,7 @@ DecodeStatus ThumbDisassembler::getInstruction(MCInst &MI, uint64_t &Size,
                                                raw_ostream &CS) const {
   CommentStream = &CS;
 
-  assert((STI.getFeatureBits() & ARM::ModeThumb) &&
+  assert(STI.getFeatureBits()[ARM::ModeThumb] &&
          "Asked to disassemble in Thumb mode but Subtarget is in ARM mode!");
 
   // We want to read exactly 2 bytes of data.
@@ -1026,9 +1026,10 @@ static const uint16_t DPRDecoderTable[] = {
 
 static DecodeStatus DecodeDPRRegisterClass(MCInst &Inst, unsigned RegNo,
                                    uint64_t Address, const void *Decoder) {
-  uint64_t featureBits = ((const MCDisassembler*)Decoder)->getSubtargetInfo()
-                                                          .getFeatureBits();
-  bool hasD16 = featureBits & ARM::FeatureD16;
+  const FeatureBitset &featureBits =
+    ((const MCDisassembler*)Decoder)->getSubtargetInfo().getFeatureBits();
+
+  bool hasD16 = featureBits[ARM::FeatureD16];
 
   if (RegNo > 31 || (hasD16 && RegNo > 15))
     return MCDisassembler::Fail;
@@ -1373,9 +1374,9 @@ static DecodeStatus DecodeCopMemInstruction(MCInst &Inst, unsigned Insn,
       break;
   }
 
-  uint64_t featureBits = ((const MCDisassembler*)Decoder)->getSubtargetInfo()
-                                                          .getFeatureBits();
-  if ((featureBits & ARM::HasV8Ops) && (coproc != 14))
+  const FeatureBitset &featureBits =
+    ((const MCDisassembler*)Decoder)->getSubtargetInfo().getFeatureBits();
+  if (featureBits[ARM::HasV8Ops] && (coproc != 14))
     return MCDisassembler::Fail;
 
   Inst.addOperand(MCOperand::createImm(coproc));
@@ -2151,9 +2152,10 @@ static DecodeStatus DecodeSETPANInstruction(MCInst &Inst, unsigned Insn,
   unsigned Imm = fieldFromInstruction(Insn, 9, 1);
 
   const MCDisassembler *Dis = static_cast<const MCDisassembler*>(Decoder);
-  uint64_t FeatureBits = Dis->getSubtargetInfo().getFeatureBits();
-  if ((FeatureBits & ARM::HasV8_1aOps) == 0 || 
-      (FeatureBits & ARM::HasV8Ops) == 0 )
+  const FeatureBitset &FeatureBits = Dis->getSubtargetInfo().getFeatureBits();
+
+  if (!FeatureBits[ARM::HasV8_1aOps] || 
+      !FeatureBits[ARM::HasV8Ops])
     return MCDisassembler::Fail;
 
   // Decoder can be called from DecodeTST, which does not check the full
@@ -3319,10 +3321,11 @@ static DecodeStatus DecodeT2LoadShift(MCInst &Inst, unsigned Insn,
   unsigned Rt = fieldFromInstruction(Insn, 12, 4);
   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
 
-  uint64_t featureBits = ((const MCDisassembler*)Decoder)->getSubtargetInfo()
-                                                          .getFeatureBits();
-  bool hasMP = featureBits & ARM::FeatureMP;
-  bool hasV7Ops = featureBits & ARM::HasV7Ops;
+  const FeatureBitset &featureBits =
+    ((const MCDisassembler*)Decoder)->getSubtargetInfo().getFeatureBits();
+
+  bool hasMP = featureBits[ARM::FeatureMP];
+  bool hasV7Ops = featureBits[ARM::HasV7Ops];
 
   if (Rn == 15) {
     switch (Inst.getOpcode()) {
@@ -3405,10 +3408,11 @@ static DecodeStatus DecodeT2LoadImm8(MCInst &Inst, unsigned Insn,
   imm |= (Rn << 9);
   unsigned add = fieldFromInstruction(Insn, 9, 1);
 
-  uint64_t featureBits = ((const MCDisassembler*)Decoder)->getSubtargetInfo()
-                                                          .getFeatureBits();
-  bool hasMP = featureBits & ARM::FeatureMP;
-  bool hasV7Ops = featureBits & ARM::HasV7Ops;
+  const FeatureBitset &featureBits =
+    ((const MCDisassembler*)Decoder)->getSubtargetInfo().getFeatureBits();
+
+  bool hasMP = featureBits[ARM::FeatureMP];
+  bool hasV7Ops = featureBits[ARM::HasV7Ops];
 
   if (Rn == 15) {
     switch (Inst.getOpcode()) {
@@ -3485,10 +3489,11 @@ static DecodeStatus DecodeT2LoadImm12(MCInst &Inst, unsigned Insn,
   unsigned imm = fieldFromInstruction(Insn, 0, 12);
   imm |= (Rn << 13);
 
-  uint64_t featureBits = ((const MCDisassembler*)Decoder)->getSubtargetInfo()
-                                                          .getFeatureBits();
-  bool hasMP = (featureBits & ARM::FeatureMP);
-  bool hasV7Ops = (featureBits & ARM::HasV7Ops);
+  const FeatureBitset &featureBits =
+    ((const MCDisassembler*)Decoder)->getSubtargetInfo().getFeatureBits();
+
+  bool hasMP = featureBits[ARM::FeatureMP];
+  bool hasV7Ops = featureBits[ARM::HasV7Ops];
 
   if (Rn == 15) {
     switch (Inst.getOpcode()) {
@@ -3602,9 +3607,10 @@ static DecodeStatus DecodeT2LoadLabel(MCInst &Inst, unsigned Insn,
   unsigned U = fieldFromInstruction(Insn, 23, 1);
   int imm = fieldFromInstruction(Insn, 0, 12);
 
-  uint64_t featureBits = ((const MCDisassembler*)Decoder)->getSubtargetInfo()
-                                                          .getFeatureBits();
-  bool hasV7Ops = (featureBits & ARM::HasV7Ops);
+  const FeatureBitset &featureBits =
+    ((const MCDisassembler*)Decoder)->getSubtargetInfo().getFeatureBits();
+
+  bool hasV7Ops = featureBits[ARM::HasV7Ops];
 
   if (Rt == 15) {
     switch (Inst.getOpcode()) {
@@ -3925,9 +3931,10 @@ static DecodeStatus DecodeCoprocessor(MCInst &Inst, unsigned Val,
   if (Val == 0xA || Val == 0xB)
     return MCDisassembler::Fail;
 
-  uint64_t featureBits = ((const MCDisassembler*)Decoder)->getSubtargetInfo()
-                                                          .getFeatureBits();
-  if ((featureBits & ARM::HasV8Ops) && !(Val == 14 || Val == 15))
+  const FeatureBitset &featureBits =
+    ((const MCDisassembler*)Decoder)->getSubtargetInfo().getFeatureBits();
+
+  if (featureBits[ARM::HasV8Ops] && !(Val == 14 || Val == 15))
     return MCDisassembler::Fail;
 
   Inst.addOperand(MCOperand::createImm(Val));
@@ -4077,9 +4084,10 @@ static DecodeStatus DecodeInstSyncBarrierOption(MCInst &Inst, unsigned Val,
 static DecodeStatus DecodeMSRMask(MCInst &Inst, unsigned Val,
                           uint64_t Address, const void *Decoder) {
   DecodeStatus S = MCDisassembler::Success;
-  uint64_t FeatureBits = ((const MCDisassembler*)Decoder)->getSubtargetInfo()
-                                                          .getFeatureBits();
-  if (FeatureBits & ARM::FeatureMClass) {
+  const FeatureBitset &FeatureBits =
+    ((const MCDisassembler*)Decoder)->getSubtargetInfo().getFeatureBits();
+
+  if (FeatureBits[ARM::FeatureMClass]) {
     unsigned ValLow = Val & 0xff;
 
     // Validate the SYSm value first.
@@ -4099,7 +4107,7 @@ static DecodeStatus DecodeMSRMask(MCInst &Inst, unsigned Val,
     case 17: // basepri
     case 18: // basepri_max
     case 19: // faultmask
-      if (!(FeatureBits & ARM::HasV7Ops))
+      if (!(FeatureBits[ARM::HasV7Ops]))
         // Values basepri, basepri_max and faultmask are only valid for v7m.
         return MCDisassembler::Fail;
       break;
@@ -4109,7 +4117,7 @@ static DecodeStatus DecodeMSRMask(MCInst &Inst, unsigned Val,
 
     if (Inst.getOpcode() == ARM::t2MSR_M) {
       unsigned Mask = fieldFromInstruction(Val, 10, 2);
-      if (!(FeatureBits & ARM::HasV7Ops)) {
+      if (!(FeatureBits[ARM::HasV7Ops])) {
         // The ARMv6-M MSR bits {11-10} can be only 0b10, other values are
         // unpredictable.
         if (Mask != 2)
@@ -4123,7 +4131,7 @@ static DecodeStatus DecodeMSRMask(MCInst &Inst, unsigned Val,
         // indicates the move for the GE{3:0} bits, the mask{0} bit can be set
         // only if the processor includes the DSP extension.
         if (Mask == 0 || (Mask != 2 && ValLow > 3) ||
-            (!(FeatureBits & ARM::FeatureDSPThumb2) && (Mask & 1)))
+            (!(FeatureBits[ARM::FeatureDSPThumb2]) && (Mask & 1)))
           S = MCDisassembler::SoftFail;
       }
     }