Allow targets to optionally specify custom binary encoder functions for

operand values. This is useful for operands which require additional trickery
to encode into the instruction. For example, the ARM shifted immediate and
shifted register operands.

llvm-svn: 116353

utils/TableGen/CodeEmitterGen.cpp

@@ -154,7 +154,6 @@ void CodeEmitterGen::run(raw_ostream &o) {
             }
 
             if (!gotOp) {
-
               // If the operand matches by name, reference according to that
               // operand number. Non-matching operands are assumed to be in
               // order.
@@ -171,10 +170,26 @@ void CodeEmitterGen::run(raw_ostream &o) {
                   ++NumberedOp;
                 OpIdx = NumberedOp++;
               }
+              std::pair<unsigned, unsigned> SO = CGI.getSubOperandNumber(OpIdx);
+              std::string &EncoderMethodName =
+                CGI.OperandList[SO.first].EncoderMethodName;
 
+              // If the source operand has a custom encoder, use it. This will
+              // get the encoding for all of the suboperands.
+              if (!EncoderMethodName.empty()) {
+                // A custom encoder has all of the information for the
+                // sub-operands, if there are more than one, so only
+                // query the encoder once per source operand.
+                if (SO.second == 0) {
+                  Case += "      // op: " + VarName + "\n"
+                       + "      op = " + EncoderMethodName + "(MI, "
+                       + utostr(OpIdx) + ");\n";
+                }
+              } else {
                 Case += "      // op: " + VarName + "\n"
                      +  "      op = getMachineOpValue(MI, MI.getOperand("
                      +  utostr(OpIdx) + "));\n";
+              }
               gotOp = true;
             }
 

utils/TableGen/CodeGenInstruction.cpp

@@ -166,10 +166,14 @@ CodeGenInstruction::CodeGenInstruction(Record *R, const std::string &AsmStr)
 
     Record *Rec = Arg->getDef();
     std::string PrintMethod = "printOperand";
+    std::string EncoderMethod;
     unsigned NumOps = 1;
     DagInit *MIOpInfo = 0;
     if (Rec->isSubClassOf("Operand")) {
       PrintMethod = Rec->getValueAsString("PrintMethod");
+      // If there is an explicit encoder method, use it.
+      if (Rec->getValue("EncoderMethod"))
+        EncoderMethod = Rec->getValueAsString("EncoderMethod");
       MIOpInfo = Rec->getValueAsDag("MIOperandInfo");
 
       // Verify that MIOpInfo has an 'ops' root value.
@@ -204,7 +208,7 @@ CodeGenInstruction::CodeGenInstruction(Record *R, const std::string &AsmStr)
       throw "In instruction '" + R->getName() + "', operand #" + utostr(i) +
         " has the same name as a previous operand!";
 
-    OperandList.push_back(OperandInfo(Rec, ArgName, PrintMethod,
+    OperandList.push_back(OperandInfo(Rec, ArgName, PrintMethod, EncoderMethod,
                                       MIOperandNo, NumOps, MIOpInfo));
     MIOperandNo += NumOps;
   }

utils/TableGen/CodeGenInstruction.h

@@ -78,6 +78,10 @@ namespace llvm {
       /// the asmprinter.
       std::string PrinterMethodName;
 
+      /// EncoderMethodName - The method used to get the machine operand value
+      /// for binary encoding. "getMachineOpValue" by default.
+      std::string EncoderMethodName;
+
       /// MIOperandNo - Currently (this is meant to be phased out), some logical
       /// operands correspond to multiple MachineInstr operands.  In the X86
       /// target for example, one address operand is represented as 4
@@ -101,9 +105,10 @@ namespace llvm {
       std::vector<ConstraintInfo> Constraints;
 
       OperandInfo(Record *R, const std::string &N, const std::string &PMN,
-                  unsigned MION, unsigned MINO, DagInit *MIOI)
+                  const std::string &EMN, unsigned MION, unsigned MINO,
-        : Rec(R), Name(N), PrinterMethodName(PMN), MIOperandNo(MION),
+                  DagInit *MIOI)
-          MINumOperands(MINO), MIOperandInfo(MIOI) {}
+        : Rec(R), Name(N), PrinterMethodName(PMN), EncoderMethodName(EMN),
+          MIOperandNo(MION), MINumOperands(MINO), MIOperandInfo(MIOI) {}
     };
 
     /// NumDefs - Number of def operands declared, this is the number of