Add support for asm printing machine instructions that have operands.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@15391 91177308-0d34-0410-b5e6-96231b3b80d8

utils/TableGen/AsmWriterEmitter.cpp

@@ -17,6 +17,13 @@
 #include <ostream>
 using namespace llvm;
 
+static bool isIdentChar(char C) {
+  return (C >= 'a' && C <= 'z') ||
+         (C >= 'A' && C <= 'Z') ||
+         (C >= '0' && C <= '9') ||
+         C == '_';
+}
+
 void AsmWriterEmitter::run(std::ostream &O) {
   EmitSourceFileHeader("Assembly Writer Source Fragment", O);
 
@@ -37,8 +44,47 @@ void AsmWriterEmitter::run(std::ostream &O) {
          E = Target.inst_end(); I != E; ++I)
     if (!I->second.AsmString.empty()) {
       const std::string &AsmString = I->second.AsmString;
-      O << "  case " << Namespace << "::" << I->first << ": O << \""
-        << AsmString << "\" << '\\n'; break;\n";
+      O << "  case " << Namespace << "::" << I->first << ": O ";
+
+      std::string::size_type LastEmitted = 0;
+      while (LastEmitted != AsmString.size()) {
+        std::string::size_type DollarPos = AsmString.find('$', LastEmitted);
+        if (DollarPos == std::string::npos) DollarPos = AsmString.size();
+
+        // Emit a constant string fragment.
+        if (DollarPos != LastEmitted) {
+          // TODO: this should eventually handle escaping.
+          O << " << \"" << std::string(AsmString.begin()+LastEmitted,
+                                       AsmString.begin()+DollarPos) << "\"";
+          LastEmitted = DollarPos;
+        } else if (DollarPos+1 != AsmString.size() &&
+                   AsmString[DollarPos+1] == '$') {
+          O << " << '$'";         // "$$" -> $
+        } else {
+          // Get the name of the variable.
+          // TODO: should eventually handle ${foo}bar as $foo
+          std::string::size_type VarEnd = DollarPos+1;
+          while (VarEnd < AsmString.size() && isIdentChar(AsmString[VarEnd]))
+            ++VarEnd;
+          std::string VarName(AsmString.begin()+DollarPos+1,
+                              AsmString.begin()+VarEnd);
+          if (VarName.empty())
+            throw "Stray '$' in '" + I->first +
+                  "' asm string, maybe you want $$?";
+          unsigned OpNo = I->second.getOperandNamed(VarName);
+
+          // If this is a two-address instruction and we are not accessing the
+          // 0th operand, remove an operand.
+          if (I->second.isTwoAddress && OpNo != 0)
+            --OpNo;
+
+          O << ";  printOperand(MI->getOperand(" << OpNo << "), MVT::"
+            << getName(I->second.OperandList[OpNo].Ty) << "); O ";
+          LastEmitted = VarEnd;
+        }
+      }
+
+      O << " << '\\n'; break;\n";
     }
 
   O << "  }\n"