3 files changed, 42 insertions, 5 deletions

diff --git a/include/llvm/MC/MCRegisterInfo.h b/include/llvm/MC/MCRegisterInfo.h
index 27acf2f2cc..47f57495c1 100644
--- a/include/llvm/MC/MCRegisterInfo.h
+++ b/include/llvm/MC/MCRegisterInfo.h
@@ -146,6 +146,8 @@ private:
   const uint16_t *SubRegIndices;              // Pointer to the subreg lookup
                                               // array.
   unsigned NumSubRegIndices;                  // Number of subreg indices.
+  const uint16_t *RegEncodingTable;           // Pointer to array of register
+                                              // encodings.
 
   unsigned L2DwarfRegsSize;
   unsigned EHL2DwarfRegsSize;
@@ -164,7 +166,8 @@ public:
                           const MCRegisterClass *C, unsigned NC,
                           const uint16_t *RL,
                           const uint16_t *SubIndices,
-                          unsigned NumIndices) {
+                          unsigned NumIndices,
+                          const uint16_t *RET) {
     Desc = D;
     NumRegs = NR;
     RAReg = RA;
@@ -173,6 +176,7 @@ public:
     NumClasses = NC;
     SubRegIndices = SubIndices;
     NumSubRegIndices = NumIndices;
+    RegEncodingTable = RET;
   }
 
   /// mapLLVMRegsToDwarfRegs - Used to initialize LLVM register to Dwarf
@@ -354,6 +358,14 @@ public:
     assert(i < getNumRegClasses() && "Register Class ID out of range");
     return Classes[i];
   }
+
+   /// getEncodingValue - Returns the encoding for RegNo
+  uint16_t getEncodingValue(unsigned RegNo) const {
+    assert(RegNo < NumRegs &&
+           "Attempting to get encoding for invalid register number!");
+    return RegEncodingTable[RegNo];
+  }
+
 };
 
 } // End llvm namespace
diff --git a/include/llvm/Target/Target.td b/include/llvm/Target/Target.td
index bd959d067f..1f2bd470b7 100644
--- a/include/llvm/Target/Target.td
+++ b/include/llvm/Target/Target.td
@@ -96,6 +96,9 @@ class Register<string n, list<string> altNames = []> {
   // x86 register AX is covered by its sub-registers AL and AH, but EAX is not
   // covered by its sub-register AX.
   bit CoveredBySubRegs = 0;
+
+  // HWEncoding - The target specific hardware encoding for this register.
+  bits<16> HWEncoding = 0;
 }
 
 // RegisterWithSubRegs - This can be used to define instances of Register which
diff --git a/utils/TableGen/RegisterInfoEmitter.cpp b/utils/TableGen/RegisterInfoEmitter.cpp
index 5b4a876e1b..98bb611126 100644
--- a/utils/TableGen/RegisterInfoEmitter.cpp
+++ b/utils/TableGen/RegisterInfoEmitter.cpp
@@ -636,6 +636,23 @@ RegisterInfoEmitter::runMCDesc(raw_ostream &OS, CodeGenTarget &Target,
 
   EmitRegMappingTables(OS, Regs, false);
 
+  // Emit Reg encoding table
+  OS << "extern const uint16_t " << TargetName;
+  OS << "RegEncodingTable[] = {\n";
+  // Add entry for NoRegister
+  OS << "  0,\n";
+  for (unsigned i = 0, e = Regs.size(); i != e; ++i) {
+    Record *Reg = Regs[i]->TheDef;
+    BitsInit *BI = Reg->getValueAsBitsInit("HWEncoding");
+    uint64_t Value = 0;
+    for (unsigned b = 0, be = BI->getNumBits(); b != be; ++b) {
+      if (BitInit *B = dynamic_cast<BitInit*>(BI->getBit(b)))
+      Value |= (uint64_t)B->getValue() << b;
+    }
+    OS << "  " << Value << ",\n";
+  }
+  OS << "};\n";       // End of HW encoding table
+
   // MCRegisterInfo initialization routine.
   OS << "static inline void Init" << TargetName
      << "MCRegisterInfo(MCRegisterInfo *RI, unsigned RA, "
@@ -645,9 +662,11 @@ RegisterInfoEmitter::runMCDesc(raw_ostream &OS, CodeGenTarget &Target,
      << RegisterClasses.size() << ", " << TargetName << "RegLists, ";
   if (SubRegIndices.size() != 0)
     OS << "(uint16_t*)" << TargetName << "SubRegTable, "
-       << SubRegIndices.size() << ");\n\n";
+       << SubRegIndices.size() << ",\n";
   else
-    OS << "NULL, 0);\n\n";
+    OS << "NULL, 0,\n";
+
+  OS << "  " << TargetName << "RegEncodingTable);\n\n";
 
   EmitRegMapping(OS, Regs, false);
 
@@ -1001,6 +1020,7 @@ RegisterInfoEmitter::runTargetDesc(raw_ostream &OS, CodeGenTarget &Target,
   if (SubRegIndices.size() != 0)
     OS << "extern const uint16_t *get" << TargetName
        << "SubRegTable();\n";
+  OS << "extern const uint16_t " << TargetName << "RegEncodingTable[];\n";
 
   EmitRegMappingTables(OS, Regs, true);
 
@@ -1016,9 +1036,11 @@ RegisterInfoEmitter::runTargetDesc(raw_ostream &OS, CodeGenTarget &Target,
      << "                     ";
   if (SubRegIndices.size() != 0)
     OS << "get" << TargetName << "SubRegTable(), "
-       << SubRegIndices.size() << ");\n\n";
+       << SubRegIndices.size() << ",\n";
   else
-    OS << "NULL, 0);\n\n";
+    OS << "NULL, 0,\n";
+
+  OS << "                     " << TargetName << "RegEncodingTable);\n\n";
 
   EmitRegMapping(OS, Regs, true);