//===-- MBlazeAsmLexer.cpp - Tokenize MBlaze assembly to AsmTokens --------===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//

#include "MBlaze.h"
#include "MBlazeTargetMachine.h"

#include "llvm/ADT/OwningPtr.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/StringExtras.h"

#include "llvm/MC/MCAsmInfo.h"
#include "llvm/MC/MCParser/MCAsmLexer.h"
#include "llvm/MC/MCParser/MCParsedAsmOperand.h"

#include "llvm/Target/TargetAsmLexer.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Target/TargetRegistry.h"

#include <string>
#include <map>

using namespace llvm;

namespace {
  
  class MBlazeBaseAsmLexer : public TargetAsmLexer {
    const MCAsmInfo &AsmInfo;
    
    const AsmToken &lexDefinite() {
      return getLexer()->Lex();
    }
    
    AsmToken LexTokenUAL();
  protected:
    typedef std::map <std::string, unsigned> rmap_ty;
    
    rmap_ty RegisterMap;
    
    void InitRegisterMap(const TargetRegisterInfo *info) {
      unsigned numRegs = info->getNumRegs();

      for (unsigned i = 0; i < numRegs; ++i) {
        const char *regName = info->getName(i);
        if (regName)
          RegisterMap[regName] = i;
      }
    }
    
    unsigned MatchRegisterName(StringRef Name) {
      rmap_ty::iterator iter = RegisterMap.find(Name.str());
      if (iter != RegisterMap.end())
        return iter->second;
      else
        return 0;
    }
    
    AsmToken LexToken() {
      if (!Lexer) {
        SetError(SMLoc(), "No MCAsmLexer installed");
        return AsmToken(AsmToken::Error, "", 0);
      }
      
      switch (AsmInfo.getAssemblerDialect()) {
      default:
        SetError(SMLoc(), "Unhandled dialect");
        return AsmToken(AsmToken::Error, "", 0);
      case 0:
        return LexTokenUAL();
      }
    }
  public:
    MBlazeBaseAsmLexer(const Target &T, const MCAsmInfo &MAI)
      : TargetAsmLexer(T), AsmInfo(MAI) {
    }
  };
  
  class MBlazeAsmLexer : public MBlazeBaseAsmLexer {
  public:
    MBlazeAsmLexer(const Target &T, const MCAsmInfo &MAI)
      : MBlazeBaseAsmLexer(T, MAI) {
      std::string tripleString("mblaze-unknown-unknown");
      std::string featureString;
      OwningPtr<const TargetMachine> 
        targetMachine(T.createTargetMachine(tripleString, featureString));
      InitRegisterMap(targetMachine->getRegisterInfo());
    }
  };
}

AsmToken MBlazeBaseAsmLexer::LexTokenUAL() {
  const AsmToken &lexedToken = lexDefinite();
  
  switch (lexedToken.getKind()) {
  default:
    return AsmToken(lexedToken);
  case AsmToken::Error:
    SetError(Lexer->getErrLoc(), Lexer->getErr());
    return AsmToken(lexedToken);
  case AsmToken::Identifier:
  {
    std::string upperCase = lexedToken.getString().str();
    std::string lowerCase = LowercaseString(upperCase);
    StringRef lowerRef(lowerCase);
    
    unsigned regID = MatchRegisterName(lowerRef);
    
    if (regID) {
      return AsmToken(AsmToken::Register,
                      lexedToken.getString(),
                      static_cast<int64_t>(regID));
    } else {
      return AsmToken(lexedToken);
    }
  }
  }
}

extern "C" void LLVMInitializeMBlazeAsmLexer() {
  RegisterAsmLexer<MBlazeAsmLexer> X(TheMBlazeTarget);
}