lib/Target/MSP430/MSP430AsmPrinter.cpp

//===-- MSP430AsmPrinter.cpp - MSP430 LLVM assembly writer ----------------===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file contains a printer that converts from our internal representation
// of machine-dependent LLVM code to the MSP430 assembly language.
//
//===----------------------------------------------------------------------===//

#define DEBUG_TYPE "asm-printer"
#include "MSP430.h"
#include "MSP430InstrInfo.h"
#include "MSP430TargetMachine.h"
#include "llvm/Constants.h"
#include "llvm/DerivedTypes.h"
#include "llvm/Module.h"
#include "llvm/CodeGen/AsmPrinter.h"
#include "llvm/CodeGen/DwarfWriter.h"
#include "llvm/CodeGen/MachineModuleInfo.h"
#include "llvm/CodeGen/MachineFunctionPass.h"
#include "llvm/CodeGen/MachineConstantPool.h"
#include "llvm/CodeGen/MachineInstr.h"
#include "llvm/Target/TargetAsmInfo.h"
#include "llvm/Target/TargetData.h"
#include "llvm/Target/TargetLoweringObjectFile.h"
#include "llvm/Target/TargetRegistry.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/Support/Compiler.h"
#include "llvm/Support/FormattedStream.h"
#include "llvm/Support/Mangler.h"
#include "llvm/Support/ErrorHandling.h"

using namespace llvm;

STATISTIC(EmittedInsts, "Number of machine instrs printed");

namespace {
  class VISIBILITY_HIDDEN MSP430AsmPrinter : public AsmPrinter {
  public:
    MSP430AsmPrinter(formatted_raw_ostream &O, TargetMachine &TM,
                     const TargetAsmInfo *TAI, bool V)
      : AsmPrinter(O, TM, TAI, V) {}

    virtual const char *getPassName() const {
      return "MSP430 Assembly Printer";
    }

    void printOperand(const MachineInstr *MI, int OpNum,
                      const char* Modifier = 0);
    void printSrcMemOperand(const MachineInstr *MI, int OpNum,
                            const char* Modifier = 0);
    void printCCOperand(const MachineInstr *MI, int OpNum);
    bool printInstruction(const MachineInstr *MI);  // autogenerated.
    void printMachineInstruction(const MachineInstr * MI);

    void emitFunctionHeader(const MachineFunction &MF);
    bool runOnMachineFunction(MachineFunction &F);

    virtual void PrintGlobalVariable(const GlobalVariable *GV) {
      // FIXME: No support for global variables?
    }

    void getAnalysisUsage(AnalysisUsage &AU) const {
      AsmPrinter::getAnalysisUsage(AU);
      AU.setPreservesAll();
    }
  };
} // end of anonymous namespace

#include "MSP430GenAsmWriter.inc"


void MSP430AsmPrinter::emitFunctionHeader(const MachineFunction &MF) {
  const Function *F = MF.getFunction();

  SwitchToSection(getObjFileLowering().SectionForGlobal(F, Mang, TM));

  unsigned FnAlign = MF.getAlignment();
  EmitAlignment(FnAlign, F);

  switch (F->getLinkage()) {
  default: llvm_unreachable("Unknown linkage type!");
  case Function::InternalLinkage:  // Symbols default to internal.
  case Function::PrivateLinkage:
  case Function::LinkerPrivateLinkage:
    break;
  case Function::ExternalLinkage:
    O << "\t.globl\t" << CurrentFnName << '\n';
    break;
  case Function::LinkOnceAnyLinkage:
  case Function::LinkOnceODRLinkage:
  case Function::WeakAnyLinkage:
  case Function::WeakODRLinkage:
    O << "\t.weak\t" << CurrentFnName << '\n';
    break;
  }

  printVisibility(CurrentFnName, F->getVisibility());

  O << "\t.type\t" << CurrentFnName << ",@function\n"
    << CurrentFnName << ":\n";
}

bool MSP430AsmPrinter::runOnMachineFunction(MachineFunction &MF) {
  SetupMachineFunction(MF);
  O << "\n\n";

  // Print the 'header' of function
  emitFunctionHeader(MF);

  // Print out code for the function.
  for (MachineFunction::const_iterator I = MF.begin(), E = MF.end();
       I != E; ++I) {
    // Print a label for the basic block.
    if (!VerboseAsm && (I->pred_empty() || I->isOnlyReachableByFallthrough())) {
      // This is an entry block or a block that's only reachable via a
      // fallthrough edge. In non-VerboseAsm mode, don't print the label.
    } else {
      printBasicBlockLabel(I, true, true, VerboseAsm);
      O << '\n';
    }

    for (MachineBasicBlock::const_iterator II = I->begin(), E = I->end();
         II != E; ++II)
      // Print the assembly for the instruction.
      printMachineInstruction(II);
  }

  if (TAI->hasDotTypeDotSizeDirective())
    O << "\t.size\t" << CurrentFnName << ", .-" << CurrentFnName << '\n';

  O.flush();

  // We didn't modify anything
  return false;
}

void MSP430AsmPrinter::printMachineInstruction(const MachineInstr *MI) {
  ++EmittedInsts;

  // Call the autogenerated instruction printer routines.
  if (printInstruction(MI))
    return;

  llvm_unreachable("Should not happen");
}

void MSP430AsmPrinter::printOperand(const MachineInstr *MI, int OpNum,
                                    const char* Modifier) {
  const MachineOperand &MO = MI->getOperand(OpNum);
  switch (MO.getType()) {
  case MachineOperand::MO_Register:
    assert (TargetRegisterInfo::isPhysicalRegister(MO.getReg()) &&
            "Virtual registers should be already mapped!");
    O << TM.getRegisterInfo()->get(MO.getReg()).AsmName;
    return;
  case MachineOperand::MO_Immediate:
    if (!Modifier || strcmp(Modifier, "nohash"))
      O << '#';
    O << MO.getImm();
    return;
  case MachineOperand::MO_MachineBasicBlock:
    printBasicBlockLabel(MO.getMBB());
    return;
  case MachineOperand::MO_GlobalAddress: {
    bool isMemOp  = Modifier && !strcmp(Modifier, "mem");
    bool isCallOp = Modifier && !strcmp(Modifier, "call");
    std::string Name = Mang->getMangledName(MO.getGlobal());
    assert(MO.getOffset() == 0 && "No offsets allowed!");

    if (isCallOp)
      O << '#';
    else if (isMemOp)
      O << '&';

    O << Name;

    return;
  }
  case MachineOperand::MO_ExternalSymbol: {
    bool isCallOp = Modifier && !strcmp(Modifier, "call");
    std::string Name(TAI->getGlobalPrefix());
    Name += MO.getSymbolName();
    if (isCallOp)
      O << '#';
    O << Name;
    return;
  }
  default:
    llvm_unreachable("Not implemented yet!");
  }
}

void MSP430AsmPrinter::printSrcMemOperand(const MachineInstr *MI, int OpNum,
                                          const char* Modifier) {
  const MachineOperand &Base = MI->getOperand(OpNum);
  const MachineOperand &Disp = MI->getOperand(OpNum+1);

  if (Base.isGlobal())
    printOperand(MI, OpNum, "mem");
  else if (Disp.isImm() && !Base.getReg())
    printOperand(MI, OpNum);
  else if (Base.getReg()) {
    if (Disp.getImm()) {
      printOperand(MI, OpNum + 1, "nohash");
      O << '(';
      printOperand(MI, OpNum);
      O << ')';
    } else {
      O << '@';
      printOperand(MI, OpNum);
    }
  } else
    llvm_unreachable("Unsupported memory operand");
}

void MSP430AsmPrinter::printCCOperand(const MachineInstr *MI, int OpNum) {
  unsigned CC = MI->getOperand(OpNum).getImm();

  switch (CC) {
  default:
   llvm_unreachable("Unsupported CC code");
   break;
  case MSP430::COND_E:
   O << "eq";
   break;
  case MSP430::COND_NE:
   O << "ne";
   break;
  case MSP430::COND_HS:
   O << "hs";
   break;
  case MSP430::COND_LO:
   O << "lo";
   break;
  case MSP430::COND_GE:
   O << "ge";
   break;
  case MSP430::COND_L:
   O << 'l';
   break;
  }
}

extern "C" void LLVMInitializeMSP430Target() { 
  // Register the target.
  RegisterTargetMachine<MSP430TargetMachine> X(TheMSP430Target);
  RegisterAsmPrinter<MSP430AsmPrinter> Y(TheMSP430Target);
}