1 files changed, 107 insertions, 11 deletions

diff --git a/include/llvm/CodeGen/Register.h b/include/llvm/CodeGen/Register.h
index 907c1a99e56f..aa5173684e24 100644
--- a/include/llvm/CodeGen/Register.h
+++ b/include/llvm/CodeGen/Register.h
@@ -9,6 +9,7 @@
 #ifndef LLVM_CODEGEN_REGISTER_H
 #define LLVM_CODEGEN_REGISTER_H
 
+#include "llvm/MC/MCRegister.h"
 #include <cassert>
 
 namespace llvm {
@@ -20,41 +21,136 @@ class Register {
 
 public:
   Register(unsigned Val = 0): Reg(Val) {}
+  Register(MCRegister Val): Reg(Val) {}
+
+  // Register numbers can represent physical registers, virtual registers, and
+  // sometimes stack slots. The unsigned values are divided into these ranges:
+  //
+  //   0           Not a register, can be used as a sentinel.
+  //   [1;2^30)    Physical registers assigned by TableGen.
+  //   [2^30;2^31) Stack slots. (Rarely used.)
+  //   [2^31;2^32) Virtual registers assigned by MachineRegisterInfo.
+  //
+  // Further sentinels can be allocated from the small negative integers.
+  // DenseMapInfo<unsigned> uses -1u and -2u.
+
+  /// isStackSlot - Sometimes it is useful the be able to store a non-negative
+  /// frame index in a variable that normally holds a register. isStackSlot()
+  /// returns true if Reg is in the range used for stack slots.
+  ///
+  /// Note that isVirtualRegister() and isPhysicalRegister() cannot handle stack
+  /// slots, so if a variable may contains a stack slot, always check
+  /// isStackSlot() first.
+  ///
+  static bool isStackSlot(unsigned Reg) {
+    return MCRegister::isStackSlot(Reg);
+  }
+
+  /// Compute the frame index from a register value representing a stack slot.
+  static int stackSlot2Index(unsigned Reg) {
+    assert(isStackSlot(Reg) && "Not a stack slot");
+    return int(Reg - (1u << 30));
+  }
+
+  /// Convert a non-negative frame index to a stack slot register value.
+  static unsigned index2StackSlot(int FI) {
+    assert(FI >= 0 && "Cannot hold a negative frame index.");
+    return FI + (1u << 30);
+  }
+
+  /// Return true if the specified register number is in
+  /// the physical register namespace.
+  static bool isPhysicalRegister(unsigned Reg) {
+    return MCRegister::isPhysicalRegister(Reg);
+  }
+
+  /// Return true if the specified register number is in
+  /// the virtual register namespace.
+  static bool isVirtualRegister(unsigned Reg) {
+    assert(!isStackSlot(Reg) && "Not a register! Check isStackSlot() first.");
+    return int(Reg) < 0;
+  }
+
+  /// Convert a virtual register number to a 0-based index.
+  /// The first virtual register in a function will get the index 0.
+  static unsigned virtReg2Index(unsigned Reg) {
+    assert(isVirtualRegister(Reg) && "Not a virtual register");
+    return Reg & ~(1u << 31);
+  }
+
+  /// Convert a 0-based index to a virtual register number.
+  /// This is the inverse operation of VirtReg2IndexFunctor below.
+  static unsigned index2VirtReg(unsigned Index) {
+    return Index | (1u << 31);
+  }
 
   /// Return true if the specified register number is in the virtual register
   /// namespace.
   bool isVirtual() const {
-    return int(Reg) < 0;
+    return isVirtualRegister(Reg);
   }
 
   /// Return true if the specified register number is in the physical register
   /// namespace.
   bool isPhysical() const {
-    return int(Reg) > 0;
+    return isPhysicalRegister(Reg);
   }
 
   /// Convert a virtual register number to a 0-based index. The first virtual
   /// register in a function will get the index 0.
   unsigned virtRegIndex() const {
-    assert(isVirtual() && "Not a virtual register");
-    return Reg & ~(1u << 31);
-  }
-
-  /// Convert a 0-based index to a virtual register number.
-  /// This is the inverse operation of VirtReg2IndexFunctor below.
-  static Register index2VirtReg(unsigned Index) {
-    return Register(Index | (1u << 31));
+    return virtReg2Index(Reg);
   }
 
   operator unsigned() const {
     return Reg;
   }
 
+  unsigned id() const { return Reg; }
+
+  operator MCRegister() const {
+    return MCRegister(Reg);
+  }
+
   bool isValid() const {
     return Reg != 0;
   }
+
+  /// Comparisons between register objects
+  bool operator==(const Register &Other) const { return Reg == Other.Reg; }
+  bool operator!=(const Register &Other) const { return Reg != Other.Reg; }
+  bool operator==(const MCRegister &Other) const { return Reg == Other.id(); }
+  bool operator!=(const MCRegister &Other) const { return Reg != Other.id(); }
+
+  /// Comparisons against register constants. E.g.
+  /// * R == AArch64::WZR
+  /// * R == 0
+  /// * R == VirtRegMap::NO_PHYS_REG
+  bool operator==(unsigned Other) const { return Reg == Other; }
+  bool operator!=(unsigned Other) const { return Reg != Other; }
+  bool operator==(int Other) const { return Reg == unsigned(Other); }
+  bool operator!=(int Other) const { return Reg != unsigned(Other); }
+  // MSVC requires that we explicitly declare these two as well.
+  bool operator==(MCPhysReg Other) const { return Reg == unsigned(Other); }
+  bool operator!=(MCPhysReg Other) const { return Reg != unsigned(Other); }
+};
+
+// Provide DenseMapInfo for Register
+template<> struct DenseMapInfo<Register> {
+  static inline unsigned getEmptyKey() {
+    return DenseMapInfo<unsigned>::getEmptyKey();
+  }
+  static inline unsigned getTombstoneKey() {
+    return DenseMapInfo<unsigned>::getTombstoneKey();
+  }
+  static unsigned getHashValue(const Register &Val) {
+    return DenseMapInfo<unsigned>::getHashValue(Val.id());
+  }
+  static bool isEqual(const Register &LHS, const Register &RHS) {
+    return DenseMapInfo<unsigned>::isEqual(LHS.id(), RHS.id());
+  }
 };
 
 }
 
-#endif
+#endif // ifndef LLVM_CODEGEN_REGISTER_H