lib/Target/ARM/ARMAsmPrinter.cpp

//===-- ARMAsmPrinter.cpp - ARM LLVM assembly writer ----------------------===//
//
//                     The LLVM Compiler Infrastructure
//
// This file was developed by the "Instituto Nokia de Tecnologia" and
// 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 GAS-format ARM assembly language.
//
//===----------------------------------------------------------------------===//

#include "ARM.h"
#include "ARMInstrInfo.h"
#include "llvm/Constants.h"
#include "llvm/DerivedTypes.h"
#include "llvm/Module.h"
#include "llvm/Assembly/Writer.h"
#include "llvm/CodeGen/AsmPrinter.h"
#include "llvm/CodeGen/MachineFunctionPass.h"
#include "llvm/CodeGen/MachineConstantPool.h"
#include "llvm/CodeGen/MachineInstr.h"
#include "llvm/Target/TargetData.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Support/Mangler.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/MathExtras.h"
#include <cctype>
#include <iostream>
using namespace llvm;

namespace {
  Statistic<> EmittedInsts("asm-printer", "Number of machine instrs printed");

  struct ARMAsmPrinter : public AsmPrinter {
    ARMAsmPrinter(std::ostream &O, TargetMachine &TM) : AsmPrinter(O, TM) {
      Data16bitsDirective = "\t.half\t";
      Data32bitsDirective = "\t.word\t";
      Data64bitsDirective = 0;
      ZeroDirective = "\t.skip\t";
      CommentString = "!";
      ConstantPoolSection = "\t.section \".rodata\",#alloc\n";
      AlignmentIsInBytes = false;
    }

    /// We name each basic block in a Function with a unique number, so
    /// that we can consistently refer to them later. This is cleared
    /// at the beginning of each call to runOnMachineFunction().
    ///
    typedef std::map<const Value *, unsigned> ValueMapTy;
    ValueMapTy NumberForBB;

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

    void printMemRegImm(const MachineInstr *MI, unsigned OpNo) {
      printOperand(MI, OpNo + 1);
      O << ", ";
      printOperand(MI, OpNo);
    }

    void printOperand(const MachineInstr *MI, int opNum);
    void printMemOperand(const MachineInstr *MI, int opNum,
                         const char *Modifier = 0);
    void printCCOperand(const MachineInstr *MI, int opNum);

    bool printInstruction(const MachineInstr *MI);  // autogenerated.
    bool runOnMachineFunction(MachineFunction &F);
    bool doInitialization(Module &M);
    bool doFinalization(Module &M);
  };
} // end of anonymous namespace

#include "ARMGenAsmWriter.inc"

/// createARMCodePrinterPass - Returns a pass that prints the ARM
/// assembly code for a MachineFunction to the given output stream,
/// using the given target machine description.  This should work
/// regardless of whether the function is in SSA form.
///
FunctionPass *llvm::createARMCodePrinterPass(std::ostream &o,
                                               TargetMachine &tm) {
  return new ARMAsmPrinter(o, tm);
}

/// runOnMachineFunction - This uses the printMachineInstruction()
/// method to print assembly for each instruction.
///
bool ARMAsmPrinter::runOnMachineFunction(MachineFunction &MF) {
  SetupMachineFunction(MF);
  O << "\n\n";

  // Print out constants referenced by the function
  EmitConstantPool(MF.getConstantPool());

  // Print out jump tables referenced by the function
  EmitJumpTableInfo(MF.getJumpTableInfo());

  // Print out labels for the function.
  const Function *F = MF.getFunction();
  switch (F->getLinkage()) {
  default: assert(0 && "Unknown linkage type!");
  case Function::InternalLinkage:
    SwitchToTextSection("\t.text", F);
    break;
  case Function::ExternalLinkage:
    SwitchToTextSection("\t.text", F);
    O << "\t.globl\t" << CurrentFnName << "\n";
    break;
  case Function::WeakLinkage:
  case Function::LinkOnceLinkage:
    assert(0 && "Not implemented");
    break;
  }
  EmitAlignment(2, F);
  O << CurrentFnName << ":\n";

  // 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 (I != MF.begin()) {
      printBasicBlockLabel(I, true);
      O << '\n';
    }
    for (MachineBasicBlock::const_iterator II = I->begin(), E = I->end();
         II != E; ++II) {
      // Print the assembly for the instruction.
      O << "\t";
      printInstruction(II);
    }
  }

  return false;
}

void ARMAsmPrinter::printOperand(const MachineInstr *MI, int opNum) {
  const MachineOperand &MO = MI->getOperand (opNum);
  const MRegisterInfo &RI = *TM.getRegisterInfo();
  switch (MO.getType()) {
  case MachineOperand::MO_Register:
    if (MRegisterInfo::isPhysicalRegister(MO.getReg()))
      O << LowercaseString (RI.get(MO.getReg()).Name);
    else
      assert(0 && "not implemented");
    break;
  case MachineOperand::MO_Immediate:
    O << "#" << (int)MO.getImmedValue();
    break;
  case MachineOperand::MO_MachineBasicBlock:
    assert(0 && "not implemented");
    abort();
    return;
  case MachineOperand::MO_GlobalAddress: {
    GlobalValue *GV = MO.getGlobal();
    std::string Name = Mang->getValueName(GV);
    O << Name;
  }
    break;
  case MachineOperand::MO_ExternalSymbol:
    assert(0 && "not implemented");
    abort();
    break;
  case MachineOperand::MO_ConstantPoolIndex:
    O << PrivateGlobalPrefix << "CPI" << getFunctionNumber()
      << '_' << MO.getConstantPoolIndex();
    break;
  default:
    O << "<unknown operand type>"; abort (); break;
  }
}

void ARMAsmPrinter::printMemOperand(const MachineInstr *MI, int opNum,
                                      const char *Modifier) {
  assert(0 && "not implemented");
}

void ARMAsmPrinter::printCCOperand(const MachineInstr *MI, int opNum) {
  assert(0 && "not implemented");
}

bool ARMAsmPrinter::doInitialization(Module &M) {
  Mang = new Mangler(M);
  return false; // success
}

bool ARMAsmPrinter::doFinalization(Module &M) {
  const TargetData *TD = TM.getTargetData();

  for (Module::const_global_iterator I = M.global_begin(), E = M.global_end();
       I != E; ++I) {
    if (!I->hasInitializer())   // External global require no code
      continue;

    if (EmitSpecialLLVMGlobal(I))
      continue;

    O << "\n\n";
    std::string name = Mang->getValueName(I);
    Constant *C = I->getInitializer();
    unsigned Size = TD->getTypeSize(C->getType());
    unsigned Align = TD->getTypeAlignment(C->getType());

    switch (I->getLinkage()) {
    default:
      assert(0 && "Unknown linkage type!");
      break;
    case GlobalValue::ExternalLinkage:
      O << "\t.globl " << name << "\n";
      break;
    case GlobalValue::InternalLinkage:
      break;
    }

    assert (!C->isNullValue());
    SwitchToDataSection(".data", I);

    EmitAlignment(Align, I);
    O << "\t.type " << name << ", %object\n";
    O << "\t.size " << name << ", " << Size << "\n";
    O << name << ":\n";
    EmitGlobalConstant(C);
  }
  AsmPrinter::doFinalization(M);
  return false; // success
}