llvm-project/llvm/lib/Target/ARM/AsmParser/ARMAsmLexer.cpp

//===-- ARMAsmLexer.cpp - Tokenize ARM 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 "ARM.h"
#include "ARMTargetMachine.h"

#include "llvm/ADT/OwningPtr.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/ADT/StringSwitch.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 ARMBaseAsmLexer : 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:
    ARMBaseAsmLexer(const Target &T, const MCAsmInfo &MAI)
      : TargetAsmLexer(T), AsmInfo(MAI) {
    }
  };

  class ARMAsmLexer : public ARMBaseAsmLexer {
  public:
    ARMAsmLexer(const Target &T, const MCAsmInfo &MAI)
      : ARMBaseAsmLexer(T, MAI) {
      std::string tripleString("arm-unknown-unknown");
      std::string featureString;
      OwningPtr<const TargetMachine>
        targetMachine(T.createTargetMachine(tripleString, featureString));
      InitRegisterMap(targetMachine->getRegisterInfo());
    }
  };

  class ThumbAsmLexer : public ARMBaseAsmLexer {
  public:
    ThumbAsmLexer(const Target &T, const MCAsmInfo &MAI)
      : ARMBaseAsmLexer(T, MAI) {
      std::string tripleString("thumb-unknown-unknown");
      std::string featureString;
      OwningPtr<const TargetMachine>
        targetMachine(T.createTargetMachine(tripleString, featureString));
      InitRegisterMap(targetMachine->getRegisterInfo());
    }
  };
}

AsmToken ARMBaseAsmLexer::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);
    // Check for register aliases.
    //   r13 -> sp
    //   r14 -> lr
    //   r15 -> pc
    //   ip  -> r12
    //   FIXME: Some assemblers support lots of others. Do we want them all?
    if (!regID) {
      regID = StringSwitch<unsigned>(lowerCase)
        .Case("r13", ARM::SP)
        .Case("r14", ARM::LR)
        .Case("r15", ARM::PC)
        .Case("ip", ARM::R12)
        .Default(0);
    }

    if (regID) {
      return AsmToken(AsmToken::Register,
                      lexedToken.getString(),
                      static_cast<int64_t>(regID));
    } else {
      return AsmToken(lexedToken);
    }
  }
  }
}

extern "C" void LLVMInitializeARMAsmLexer() {
  RegisterAsmLexer<ARMAsmLexer> X(TheARMTarget);
  RegisterAsmLexer<ThumbAsmLexer> Y(TheThumbTarget);
}