Write llvm-tblgen backends as functions instead of sub-classes.

The TableGenBackend base class doesn't do much, and will be removed
completely soon.

Patch by Sean Silva!

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@158311 91177308-0d34-0410-b5e6-96231b3b80d8

utils/TableGen/CodeEmitterGen.cpp

@@ -13,13 +13,15 @@
 //
 //===----------------------------------------------------------------------===//
 
-#include "CodeEmitterGen.h"
 #include "CodeGenTarget.h"
 #include "llvm/TableGen/Record.h"
 #include "llvm/ADT/StringExtras.h"
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Support/Debug.h"
+#include "llvm/TableGen/TableGenBackend.h"
 #include <map>
+#include <string>
+#include <vector>
 using namespace llvm;
 
 // FIXME: Somewhat hackish to use a command line option for this. There should
@@ -30,6 +32,27 @@ MCEmitter("mc-emitter",
           cl::desc("Generate CodeEmitter for use with the MC library."),
           cl::init(false));
 
+namespace {
+
+class CodeEmitterGen {
+  RecordKeeper &Records;
+public:
+  CodeEmitterGen(RecordKeeper &R) : Records(R) {}
+
+  void run(raw_ostream &o);
+private:
+  void emitMachineOpEmitter(raw_ostream &o, const std::string &Namespace);
+  void emitGetValueBit(raw_ostream &o, const std::string &Namespace);
+  void reverseBits(std::vector<Record*> &Insts);
+  int getVariableBit(const std::string &VarName, BitsInit *BI, int bit);
+  std::string getInstructionCase(Record *R, CodeGenTarget &Target);
+  void AddCodeToMergeInOperand(Record *R, BitsInit *BI,
+                               const std::string &VarName,
+                               unsigned &NumberedOp,
+                               std::string &Case, CodeGenTarget &Target);
+
+};
+
 void CodeEmitterGen::reverseBits(std::vector<Record*> &Insts) {
   for (std::vector<Record*>::iterator I = Insts.begin(), E = Insts.end();
        I != E; ++I) {
@@ -214,7 +237,6 @@ void CodeEmitterGen::run(raw_ostream &o) {
   // For little-endian instruction bit encodings, reverse the bit order
   if (Target.isLittleEndianEncoding()) reverseBits(Insts);
 
-  EmitSourceFileHeader("Machine Code Emitter", o);
 
   const std::vector<const CodeGenInstruction*> &NumberedInstructions =
     Target.getInstructionsByEnumValue();
@@ -304,3 +326,14 @@ void CodeEmitterGen::run(raw_ostream &o) {
     << "  return Value;\n"
     << "}\n\n";
 }
+
+} // End anonymous namespace
+
+namespace llvm {
+
+void EmitCodeEmitter(RecordKeeper &RK, raw_ostream &OS) {
+  emitSourceFileHeader("Machine Code Emitter", OS);
+  CodeEmitterGen(RK).run(OS);
+}
+
+} // End llvm namespace