Turn the DenseSet in MCRegisterClass into a tblgenerated bit field. This should be faster and smaller.

Goodbye static ctors and dtors!

llvm-svn: 135836

include/llvm/MC/MCRegisterInfo.h

@@ -17,7 +17,6 @@
 #define LLVM_MC_MCREGISTERINFO_H
 
 #include "llvm/ADT/DenseMap.h"
-#include "llvm/ADT/DenseSet.h"
 #include <cassert>
 
 namespace llvm {
@@ -34,20 +33,18 @@ private:
   const int CopyCost;
   const bool Allocatable;
   const iterator RegsBegin, RegsEnd;
-  DenseSet<unsigned> RegSet;
+  const unsigned char *RegSet;
+  const unsigned RegSetSize;
 public:
   MCRegisterClass(unsigned id, const char *name,
                   unsigned RS, unsigned Al, int CC, bool Allocable,
-                  iterator RB, iterator RE)
+                  iterator RB, iterator RE, const unsigned char *Bits,
+                  unsigned NumBytes)
     : ID(id), Name(name), RegSize(RS), Alignment(Al), CopyCost(CC),
-      Allocatable(Allocable), RegsBegin(RB), RegsEnd(RE) {}
-
-  /// initMCRegisterClass - Initialize initMCRegisterClass. *DO NOT USE*.
-  // FIXME: This could go away if RegSet would use a constant bit field.
-  void initMCRegisterClass() {
-    RegSet.resize(getNumRegs());
-    for (iterator I = RegsBegin, E = RegsEnd; I != E; ++I)
-      RegSet.insert(*I);
+      Allocatable(Allocable), RegsBegin(RB), RegsEnd(RE), RegSet(Bits),
+      RegSetSize(NumBytes) {
+    for (iterator i = RegsBegin; i != RegsEnd; ++i)
+       assert (contains(*i) && "Bit field corrupted.");
   }
 
   /// getID() - Return the register class ID number.
@@ -77,7 +74,11 @@ public:
   /// contains - Return true if the specified register is included in this
   /// register class.  This does not include virtual registers.
   bool contains(unsigned Reg) const {
-    return RegSet.count(Reg);
+    unsigned InByte = Reg % 8;
+    unsigned Byte = Reg / 8;
+    if (Byte > RegSetSize)
+      return false;
+    return (RegSet[Byte] & (1 << InByte)) != 0;
   }
 
   /// contains - Return true if both registers are in this class.
@@ -151,15 +152,12 @@ public:
   /// InitMCRegisterInfo - Initialize MCRegisterInfo, called by TableGen
   /// auto-generated routines. *DO NOT USE*.
   void InitMCRegisterInfo(const MCRegisterDesc *D, unsigned NR, unsigned RA,
-                          MCRegisterClass *C, unsigned NC) {
+                          const MCRegisterClass *C, unsigned NC) {
     Desc = D;
     NumRegs = NR;
     RAReg = RA;
     Classes = C;
     NumClasses = NC;
-    // FIXME: This should go away.
-    for (unsigned i = 0; i != NC; ++i)
-      C[i].initMCRegisterClass();
   }
 
   /// mapLLVMRegToDwarfReg - Used to initialize LLVM register to Dwarf

include/llvm/Target/TargetRegisterInfo.h

@@ -46,7 +46,7 @@ private:
   const sc_iterator SubRegClasses;
   const sc_iterator SuperRegClasses;
 public:
-  TargetRegisterClass(MCRegisterClass *MC, const EVT *vts,
+  TargetRegisterClass(const MCRegisterClass *MC, const EVT *vts,
                       const TargetRegisterClass * const *subcs,
                       const TargetRegisterClass * const *supcs,
                       const TargetRegisterClass * const *subregcs,

utils/TableGen/RegisterInfoEmitter.cpp

@@ -17,6 +17,7 @@
 #include "CodeGenTarget.h"
 #include "CodeGenRegisters.h"
 #include "Record.h"
+#include "llvm/ADT/BitVector.h"
 #include "llvm/ADT/StringExtras.h"
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/Support/Format.h"
@@ -202,6 +203,30 @@ RegisterInfoEmitter::EmitRegMapping(raw_ostream &OS,
   }
 }
 
+// Helper to emit a set of bits into a constant byte array.
+class BitVectorEmitter {
+  BitVector Values;
+  unsigned Len;
+public:
+  BitVectorEmitter(unsigned L) : Len(L%8 ? ((L/8)+1)*8 : L) {
+    Values.resize(Len);
+  }
+
+  void add(unsigned v) { Values[v] = true; }
+
+  void print(raw_ostream &OS) {
+    for (unsigned i = 0, e = Len / 8; i != e; ++i) {
+      unsigned char out = 0;
+      for (unsigned ii = 0, ie = 8; ii != ie; ++ii)
+        if (Values[i * 8 + ii])
+          out |= 1 << ii;
+      OS << "0x";
+      OS.write_hex(out);
+      OS << ", ";
+    }
+  }
+};
+
 //
 // runMCDesc - Print out MC register descriptions.
 //
@@ -320,6 +345,18 @@ RegisterInfoEmitter::runMCDesc(raw_ostream &OS, CodeGenTarget &Target,
       OS << getQualifiedName(Reg) << ", ";
     }
     OS << "\n  };\n\n";
+
+    OS << "  // " << Name << " Bit set.\n"
+       << "  static const unsigned char " << Name
+       << "Bits[] = {\n    ";
+    BitVectorEmitter BVE(Target.getRegBank().getRegisters().size()+1);
+    for (unsigned i = 0, e = Order.size(); i != e; ++i) {
+      Record *Reg = Order[i];
+      BVE.add(Target.getRegBank().getReg(Reg)->EnumValue);
+    }
+    BVE.print(OS);
+    OS << "\n  };\n\n";
+
   }
   OS << "}\n\n";
 
@@ -337,7 +374,8 @@ RegisterInfoEmitter::runMCDesc(raw_ostream &OS, CodeGenTarget &Target,
        << RC.CopyCost << ", "
        << RC.Allocatable << ", "
        << RC.getName() << ", " << RC.getName() << " + "
-       << RC.getOrder().size()
+       << RC.getOrder().size() << ", "
+       << RC.getName() << "Bits, sizeof(" << RC.getName() << "Bits)"
        << "),\n";
   }