64-bit instruction selector and AIX-specific 64-bit asm printer

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@15669 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Target/PowerPC/PPC.h

@@ -25,8 +25,9 @@ class TargetMachine;
 FunctionPass *createPowerPCPEI();
 FunctionPass *createPPCBranchSelectionPass();
 FunctionPass *createPPC32ISelSimple(TargetMachine &TM);
-FunctionPass *createPPC64ISelSimple(TargetMachine &TM);
 FunctionPass *createPPC32AsmPrinter(std::ostream &OS,TargetMachine &TM);
+FunctionPass *createPPC64ISelSimple(TargetMachine &TM);
+FunctionPass *createPPC64AsmPrinter(std::ostream &OS,TargetMachine &TM);
 
 } // end namespace llvm;
 

lib/Target/PowerPC/PPC64AsmPrinter.cpp

@@ -0,0 +1,686 @@
+//===-- PPC64AsmPrinter.cpp - Print machine instrs to PowerPC assembly ----===//
+// 
+//                     The LLVM Compiler Infrastructure
+//
+// This file was developed by the LLVM research group 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 PowerPC assembly language. This printer is
+// the output mechanism used by `llc'.
+//
+//===----------------------------------------------------------------------===//
+
+#define DEBUG_TYPE "asmprinter"
+#include "PowerPC.h"
+#include "PowerPCInstrInfo.h"
+#include "PPC64TargetMachine.h"
+#include "llvm/Constants.h"
+#include "llvm/DerivedTypes.h"
+#include "llvm/Module.h"
+#include "llvm/Assembly/Writer.h"
+#include "llvm/CodeGen/MachineConstantPool.h"
+#include "llvm/CodeGen/MachineFunctionPass.h"
+#include "llvm/CodeGen/MachineInstr.h"
+#include "llvm/Target/TargetMachine.h"
+#include "llvm/Support/Mangler.h"
+#include "Support/CommandLine.h"
+#include "Support/Debug.h"
+#include "Support/MathExtras.h"
+#include "Support/Statistic.h"
+#include "Support/StringExtras.h"
+#include <set>
+
+namespace llvm {
+
+namespace {
+  Statistic<> EmittedInsts("asm-printer", "Number of machine instrs printed");
+
+  struct Printer : public MachineFunctionPass {
+    /// Output stream on which we're printing assembly code.
+    ///
+    std::ostream &O;
+
+    /// Target machine description which we query for reg. names, data
+    /// layout, etc.
+    ///
+    PPC64TargetMachine &TM;
+
+    /// Name-mangler for global names.
+    ///
+    Mangler *Mang;
+
+    /// Map for labels corresponding to global variables
+    ///
+    std::map<const GlobalVariable*,std::string> GVToLabelMap;
+
+    Printer(std::ostream &o, TargetMachine &tm) : O(o),
+      TM(reinterpret_cast<PPC64TargetMachine&>(tm)), LabelNumber(0) {}
+
+    /// Cache of mangled name for current function. This is
+    /// recalculated at the beginning of each call to
+    /// runOnMachineFunction().
+    ///
+    std::string CurrentFnName;
+
+    /// Unique incrementer for label values for referencing Global values.
+    ///
+    unsigned LabelNumber;
+  
+    virtual const char *getPassName() const {
+      return "PPC64 Assembly Printer";
+    }
+
+    void printMachineInstruction(const MachineInstr *MI);
+    void printOp(const MachineOperand &MO, bool elideOffsetKeyword = false);
+    void printImmOp(const MachineOperand &MO, unsigned ArgType);
+    void printConstantPool(MachineConstantPool *MCP);
+    bool runOnMachineFunction(MachineFunction &F);    
+    bool doInitialization(Module &M);
+    bool doFinalization(Module &M);
+    void emitGlobalConstant(const Constant* CV);
+    void emitConstantValueOnly(const Constant *CV);
+  };
+} // end of anonymous namespace
+
+/// createPPC64AsmPrinterPass - Returns a pass that prints the PPC
+/// 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 or not.
+///
+FunctionPass *createPPC64AsmPrinter(std::ostream &o,TargetMachine &tm) {
+  return new Printer(o, tm);
+}
+
+/// isStringCompatible - Can we treat the specified array as a string?
+/// Only if it is an array of ubytes or non-negative sbytes.
+///
+static bool isStringCompatible(const ConstantArray *CVA) {
+  const Type *ETy = cast<ArrayType>(CVA->getType())->getElementType();
+  if (ETy == Type::UByteTy) return true;
+  if (ETy != Type::SByteTy) return false;
+
+  for (unsigned i = 0; i < CVA->getNumOperands(); ++i)
+    if (cast<ConstantSInt>(CVA->getOperand(i))->getValue() < 0)
+      return false;
+
+  return true;
+}
+
+/// toOctal - Convert the low order bits of X into an octal digit.
+///
+static inline char toOctal(int X) {
+  return (X&7)+'0';
+}
+
+/// getAsCString - Return the specified array as a C compatible
+/// string, only if the predicate isStringCompatible is true.
+///
+static void printAsCString(std::ostream &O, const ConstantArray *CVA) {
+  assert(isStringCompatible(CVA) && "Array is not string compatible!");
+
+  O << "\"";
+  for (unsigned i = 0; i < CVA->getNumOperands(); ++i) {
+    unsigned char C = cast<ConstantInt>(CVA->getOperand(i))->getRawValue();
+
+    if (C == '"') {
+      O << "\\\"";
+    } else if (C == '\\') {
+      O << "\\\\";
+    } else if (isprint(C)) {
+      O << C;
+    } else {
+      switch (C) {
+      case '\b': O << "\\b"; break;
+      case '\f': O << "\\f"; break;
+      case '\n': O << "\\n"; break;
+      case '\r': O << "\\r"; break;
+      case '\t': O << "\\t"; break;
+      default:
+        O << '\\';
+        O << toOctal(C >> 6);
+        O << toOctal(C >> 3);
+        O << toOctal(C >> 0);
+        break;
+      }
+    }
+  }
+  O << "\"";
+}
+
+// Print out the specified constant, without a storage class.  Only the
+// constants valid in constant expressions can occur here.
+void Printer::emitConstantValueOnly(const Constant *CV) {
+  if (CV->isNullValue())
+    O << "0";
+  else if (const ConstantBool *CB = dyn_cast<ConstantBool>(CV)) {
+    assert(CB == ConstantBool::True);
+    O << "1";
+  } else if (const ConstantSInt *CI = dyn_cast<ConstantSInt>(CV))
+    O << CI->getValue();
+  else if (const ConstantUInt *CI = dyn_cast<ConstantUInt>(CV))
+    O << CI->getValue();
+  else if (const GlobalValue *GV = dyn_cast<GlobalValue>(CV))
+    // This is a constant address for a global variable or function.  Use the
+    // name of the variable or function as the address value.
+    O << Mang->getValueName(GV);
+  else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(CV)) {
+    const TargetData &TD = TM.getTargetData();
+    switch (CE->getOpcode()) {
+    case Instruction::GetElementPtr: {
+      // generate a symbolic expression for the byte address
+      const Constant *ptrVal = CE->getOperand(0);
+      std::vector<Value*> idxVec(CE->op_begin()+1, CE->op_end());
+      if (unsigned Offset = TD.getIndexedOffset(ptrVal->getType(), idxVec)) {
+        O << "(";
+        emitConstantValueOnly(ptrVal);
+        O << ") + " << Offset;
+      } else {
+        emitConstantValueOnly(ptrVal);
+      }
+      break;
+    }
+    case Instruction::Cast: {
+      // Support only non-converting or widening casts for now, that is, ones
+      // that do not involve a change in value.  This assertion is really gross,
+      // and may not even be a complete check.
+      Constant *Op = CE->getOperand(0);
+      const Type *OpTy = Op->getType(), *Ty = CE->getType();
+
+      // Remember, kids, pointers on x86 can be losslessly converted back and
+      // forth into 32-bit or wider integers, regardless of signedness. :-P
+      assert(((isa<PointerType>(OpTy)
+               && (Ty == Type::LongTy || Ty == Type::ULongTy
+                   || Ty == Type::IntTy || Ty == Type::UIntTy))
+              || (isa<PointerType>(Ty)
+                  && (OpTy == Type::LongTy || OpTy == Type::ULongTy
+                      || OpTy == Type::IntTy || OpTy == Type::UIntTy))
+              || (((TD.getTypeSize(Ty) >= TD.getTypeSize(OpTy))
+                   && OpTy->isLosslesslyConvertibleTo(Ty))))
+             && "FIXME: Don't yet support this kind of constant cast expr");
+      O << "(";
+      emitConstantValueOnly(Op);
+      O << ")";
+      break;
+    }
+    case Instruction::Add:
+      O << "(";
+      emitConstantValueOnly(CE->getOperand(0));
+      O << ") + (";
+      emitConstantValueOnly(CE->getOperand(1));
+      O << ")";
+      break;
+    default:
+      assert(0 && "Unsupported operator!");
+    }
+  } else {
+    assert(0 && "Unknown constant value!");
+  }
+}
+
+// Print a constant value or values, with the appropriate storage class as a
+// prefix.
+void Printer::emitGlobalConstant(const Constant *CV) {  
+  const TargetData &TD = TM.getTargetData();
+
+  if (const ConstantArray *CVA = dyn_cast<ConstantArray>(CV)) {
+    if (isStringCompatible(CVA)) {
+      O << "\t.byte ";
+      printAsCString(O, CVA);
+      O << "\n";
+    } else { // Not a string.  Print the values in successive locations
+      for (unsigned i=0, e = CVA->getNumOperands(); i != e; i++)
+        emitGlobalConstant(CVA->getOperand(i));
+    }
+    return;
+  } else if (const ConstantStruct *CVS = dyn_cast<ConstantStruct>(CV)) {
+    // Print the fields in successive locations. Pad to align if needed!
+    const StructLayout *cvsLayout = TD.getStructLayout(CVS->getType());
+    unsigned sizeSoFar = 0;
+    for (unsigned i = 0, e = CVS->getNumOperands(); i != e; i++) {
+      const Constant* field = CVS->getOperand(i);
+
+      // Check if padding is needed and insert one or more 0s.
+      unsigned fieldSize = TD.getTypeSize(field->getType());
+      unsigned padSize = ((i == e-1? cvsLayout->StructSize
+                           : cvsLayout->MemberOffsets[i+1])
+                          - cvsLayout->MemberOffsets[i]) - fieldSize;
+      sizeSoFar += fieldSize + padSize;
+
+      // Now print the actual field value
+      emitGlobalConstant(field);
+
+      // Insert the field padding unless it's zero bytes...
+      if (padSize)
+        O << "\t.space\t " << padSize << "\n";      
+    }
+    assert(sizeSoFar == cvsLayout->StructSize &&
+           "Layout of constant struct may be incorrect!");
+    return;
+  } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(CV)) {
+    // FP Constants are printed as integer constants to avoid losing
+    // precision...
+    double Val = CFP->getValue();
+    switch (CFP->getType()->getTypeID()) {
+    default: assert(0 && "Unknown floating point type!");
+    case Type::FloatTyID: {
+      union FU {                            // Abide by C TBAA rules
+        float FVal;
+        unsigned UVal;
+      } U;
+      U.FVal = Val;
+      O << "\t.long " << U.UVal << "\t# float " << Val << "\n";
+      return;
+    }
+    case Type::DoubleTyID: {
+      union DU {                            // Abide by C TBAA rules
+        double FVal;
+        uint64_t UVal;
+        struct {
+          uint32_t MSWord;
+          uint32_t LSWord;
+        } T;
+      } U;
+      U.FVal = Val;
+      
+      O << ".long " << U.T.MSWord << "\t# double most significant word " 
+        << Val << "\n";
+      O << ".long " << U.T.LSWord << "\t# double least significant word " 
+        << Val << "\n";
+      return;
+    }
+    }
+  } else if (CV->getType() == Type::ULongTy || CV->getType() == Type::LongTy) {
+    if (const ConstantInt *CI = dyn_cast<ConstantInt>(CV)) {
+      union DU {                            // Abide by C TBAA rules
+        int64_t UVal;
+        struct {
+          uint32_t MSWord;
+          uint32_t LSWord;
+        } T;
+      } U;
+      U.UVal = CI->getRawValue();
+        
+      O << ".long " << U.T.MSWord << "\t# Double-word most significant word " 
+        << U.UVal << "\n";
+      O << ".long " << U.T.LSWord << "\t# Double-word least significant word " 
+        << U.UVal << "\n";
+      return;
+    }
+  }
+
+  const Type *type = CV->getType();
+  O << "\t";
+  switch (type->getTypeID()) {
+  case Type::UByteTyID: case Type::SByteTyID:
+    O << "\t.byte";
+    break;
+  case Type::UShortTyID: case Type::ShortTyID:
+    O << "\t.short";
+    break;
+  case Type::BoolTyID: 
+  case Type::PointerTyID:
+  case Type::UIntTyID: case Type::IntTyID:
+    O << "\t.long";
+    break;
+  case Type::ULongTyID: case Type::LongTyID:    
+    assert (0 && "Should have already output double-word constant.");
+  case Type::FloatTyID: case Type::DoubleTyID:
+    assert (0 && "Should have already output floating point constant.");
+  default:
+    if (CV == Constant::getNullValue(type)) {  // Zero initializer?
+      O << "\t.space " << TD.getTypeSize(type) << "\n";      
+      return;
+    }
+    std::cerr << "Can't handle printing: " << *CV;
+    abort();
+    break;
+  }
+  O << ' ';
+  emitConstantValueOnly(CV);
+  O << '\n';
+}
+
+/// printConstantPool - Print to the current output stream assembly
+/// representations of the constants in the constant pool MCP. This is
+/// used to print out constants which have been "spilled to memory" by
+/// the code generator.
+///
+void Printer::printConstantPool(MachineConstantPool *MCP) {
+  const std::vector<Constant*> &CP = MCP->getConstants();
+  const TargetData &TD = TM.getTargetData();
+ 
+  if (CP.empty()) return;
+
+  for (unsigned i = 0, e = CP.size(); i != e; ++i) {
+    O << "\t.const\n";
+    O << "\t.align " << (unsigned)TD.getTypeAlignment(CP[i]->getType())
+      << "\n";
+    O << ".CPI" << CurrentFnName << "_" << i << ":\t\t\t\t\t;"
+      << *CP[i] << "\n";
+    emitGlobalConstant(CP[i]);
+  }
+}
+
+/// runOnMachineFunction - This uses the printMachineInstruction()
+/// method to print assembly for each instruction.
+///
+bool Printer::runOnMachineFunction(MachineFunction &MF) {
+  CurrentFnName = MF.getFunction()->getName();
+
+  // Print out constants referenced by the function
+  printConstantPool(MF.getConstantPool());
+
+  // Print out header for the function.
+  O << "\t.csect .text[PR]\n"
+    << "\t.align 2\n"
+    << "\t.globl "  << CurrentFnName << '\n'
+    << "\t.globl ." << CurrentFnName << '\n'
+    << "\t.csect "  << CurrentFnName << "[DS],3\n"
+    << CurrentFnName << ":\n"
+    << "\t.llong ." << CurrentFnName << ", TOC[tc0], 0\n"
+    << "\t.csect .text[PR]\n"
+    << '.' << 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.
+    O << "LBB" << CurrentFnName << "_" << I->getNumber() << ":\t# "
+      << I->getBasicBlock()->getName() << "\n";
+    for (MachineBasicBlock::const_iterator II = I->begin(), E = I->end();
+      II != E; ++II) {
+      // Print the assembly for the instruction.
+      O << "\t";
+      printMachineInstruction(II);
+    }
+  }
+  ++LabelNumber;
+
+  O << "LT.." << CurrentFnName << ":\n"
+    << "\t.long 0\n"
+    << "\t.byte 0,0,32,65,128,0,0,0\n"
+    << "\t.long LT.." << CurrentFnName << "-." << CurrentFnName << '\n'
+    << "\t.short 3\n"
+    << "\t.byte \"" << CurrentFnName << "\"\n"
+    << "\t.align 2\n";
+
+  // We didn't modify anything.
+  return false;
+}
+
+void Printer::printOp(const MachineOperand &MO,
+                      bool elideOffsetKeyword /* = false */) {
+  const MRegisterInfo &RI = *TM.getRegisterInfo();
+  int new_symbol;
+  
+  switch (MO.getType()) {
+  case MachineOperand::MO_VirtualRegister:
+    if (Value *V = MO.getVRegValueOrNull()) {
+      O << "<" << V->getName() << ">";
+      return;
+    }
+    // FALLTHROUGH
+  case MachineOperand::MO_MachineRegister:
+  case MachineOperand::MO_CCRegister: {
+    // On AIX, do not print out the 'r' in register names
+    const char *regName = RI.get(MO.getReg()).Name;
+    O << &regName[1];
+    return;
+  }
+
+  case MachineOperand::MO_SignExtendedImmed:
+  case MachineOperand::MO_UnextendedImmed:
+    std::cerr << "printOp() does not handle immediate values\n";
+    abort();
+    return;
+
+  case MachineOperand::MO_PCRelativeDisp:
+    std::cerr << "Shouldn't use addPCDisp() when building PPC MachineInstrs";
+    abort();
+    return;
+    
+  case MachineOperand::MO_MachineBasicBlock: {
+    MachineBasicBlock *MBBOp = MO.getMachineBasicBlock();
+    O << ".LBB" << Mang->getValueName(MBBOp->getParent()->getFunction())
+      << "_" << MBBOp->getNumber() << "\t# "
+      << MBBOp->getBasicBlock()->getName();
+    return;
+  }
+
+  case MachineOperand::MO_ConstantPoolIndex:
+    O << ".CPI" << CurrentFnName << "_" << MO.getConstantPoolIndex();
+    return;
+
+  case MachineOperand::MO_ExternalSymbol:
+    O << MO.getSymbolName();
+    return;
+
+  case MachineOperand::MO_GlobalAddress:
+    if (!elideOffsetKeyword) {
+      GlobalValue *GV = MO.getGlobal();
+
+      if (Function *F = dyn_cast<Function>(GV)) {
+        O << "." << F->getName();
+      } else if (GlobalVariable *GVar = dyn_cast<GlobalVariable>(GV)) {
+        // output the label name
+        O << GVToLabelMap[GVar];
+      }
+    }
+    return;
+    
+  default:
+    O << "<unknown operand type: " << MO.getType() << ">";
+    return;
+  }
+}
+
+void Printer::printImmOp(const MachineOperand &MO, unsigned ArgType) {
+  int Imm = MO.getImmedValue();
+  if (ArgType == PPCII::Simm16 || ArgType == PPCII::Disimm16) {
+    O << (short)Imm;
+  } else if (ArgType == PPCII::Zimm16) {
+    O << (unsigned short)Imm;
+  } else {
+    O << Imm;
+  }
+}
+
+/// printMachineInstruction -- Print out a single PPC LLVM instruction
+/// MI in Darwin syntax to the current output stream.
+///
+void Printer::printMachineInstruction(const MachineInstr *MI) {
+  unsigned Opcode = MI->getOpcode();
+  const TargetInstrInfo &TII = *TM.getInstrInfo();
+  const TargetInstrDescriptor &Desc = TII.get(Opcode);
+  unsigned i;
+
+  unsigned ArgCount = MI->getNumOperands();
+  unsigned ArgType[] = {
+    (Desc.TSFlags >> PPCII::Arg0TypeShift) & PPCII::ArgTypeMask,
+    (Desc.TSFlags >> PPCII::Arg1TypeShift) & PPCII::ArgTypeMask,
+    (Desc.TSFlags >> PPCII::Arg2TypeShift) & PPCII::ArgTypeMask,
+    (Desc.TSFlags >> PPCII::Arg3TypeShift) & PPCII::ArgTypeMask,
+    (Desc.TSFlags >> PPCII::Arg4TypeShift) & PPCII::ArgTypeMask
+  };
+  assert(((Desc.TSFlags & PPCII::VMX) == 0) &&
+         "Instruction requires VMX support");
+  ++EmittedInsts;
+
+  // CALLpcrel and CALLindirect are handled specially here to print only the
+  // appropriate number of args that the assembler expects.  This is because
+  // may have many arguments appended to record the uses of registers that are
+  // holding arguments to the called function.
+  if (Opcode == PPC::COND_BRANCH) {
+    std::cerr << "Error: untranslated conditional branch psuedo instruction!\n";
+    abort();
+  } else if (Opcode == PPC::IMPLICIT_DEF) {
+    O << "# IMPLICIT DEF ";
+    printOp(MI->getOperand(0));
+    O << "\n";
+    return;
+  } else if (Opcode == PPC::CALLpcrel) {
+    O << TII.getName(Opcode) << " ";
+    printOp(MI->getOperand(0));
+    O << "\n";
+    return;
+  } else if (Opcode == PPC::CALLindirect) {
+    O << TII.getName(Opcode) << " ";
+    printImmOp(MI->getOperand(0), ArgType[0]);
+    O << ", ";
+    printImmOp(MI->getOperand(1), ArgType[0]);
+    O << "\n";
+    return;
+  } else if (Opcode == PPC::MovePCtoLR) {
+    // FIXME: should probably be converted to cout.width and cout.fill
+    O << "bl \"L0000" << LabelNumber << "$pb\"\n";
+    O << "\"L0000" << LabelNumber << "$pb\":\n";
+    O << "\tmflr ";
+    printOp(MI->getOperand(0));
+    O << "\n";
+    return;
+  }
+
+  O << TII.getName(Opcode) << " ";
+  if (Opcode == PPC::LD || Opcode == PPC::LWA || 
+      Opcode == PPC::STDU || Opcode == PPC::STDUX) {
+    printOp(MI->getOperand(0));
+    O << ", ";
+    MachineOperand MO = MI->getOperand(1);
+    if (MO.isImmediate())
+      printImmOp(MO, ArgType[1]);
+    else
+      printOp(MO);
+    O << "(";
+    printOp(MI->getOperand(2));
+    O << ")\n";
+  } else if (Opcode == PPC::BLR || Opcode == PPC::NOP) {
+    // FIXME: BuildMI() should handle 0 params
+    O << "\n";
+  } else if (ArgCount == 3 && ArgType[1] == PPCII::Disimm16) {
+    printOp(MI->getOperand(0));
+    O << ", ";
+    printImmOp(MI->getOperand(1), ArgType[1]);
+    O << "(";
+    if (MI->getOperand(2).hasAllocatedReg() &&
+        MI->getOperand(2).getReg() == PPC::R0)
+      O << "0";
+    else
+      printOp(MI->getOperand(2));
+    O << ")\n";
+  } else {
+    for (i = 0; i < ArgCount; ++i) {
+      // addi and friends
+      if (i == 1 && ArgCount == 3 && ArgType[2] == PPCII::Simm16 &&
+          MI->getOperand(1).hasAllocatedReg() && 
+          MI->getOperand(1).getReg() == PPC::R0) {
+        O << "0";
+      // for long branch support, bc $+8
+      } else if (i == 1 && ArgCount == 2 && MI->getOperand(1).isImmediate() &&
+                 TII.isBranch(MI->getOpcode())) {
+        O << "$+8";
+        assert(8 == MI->getOperand(i).getImmedValue()
+          && "branch off PC not to pc+8?");
+        //printOp(MI->getOperand(i));
+      } else if (MI->getOperand(i).isImmediate()) {
+        printImmOp(MI->getOperand(i), ArgType[i]);
+      } else {
+        printOp(MI->getOperand(i));
+      }
+      if (ArgCount - 1 == i)
+        O << "\n";
+      else
+        O << ", ";
+    }
+  }
+}
+
+// SwitchSection - Switch to the specified section of the executable if we are
+// not already in it!
+//
+static void SwitchSection(std::ostream &OS, std::string &CurSection,
+                          const char *NewSection) {
+  if (CurSection != NewSection) {
+    CurSection = NewSection;
+    if (!CurSection.empty())
+      OS << "\t" << NewSection << "\n";
+  }
+}
+
+bool Printer::doInitialization(Module &M) {
+  const TargetData &TD = TM.getTargetData();
+  std::string CurSection;
+
+  O << "\t.machine \"ppc64\"\n" 
+    << "\t.toc\n"
+    << "\t.csect .text[PR]\n";
+
+  // Print out module-level global variables
+  for (Module::const_giterator I = M.gbegin(), E = M.gend(); I != E; ++I) {
+    if (!I->hasInitializer())
+      continue;
+ 
+    std::string Name = I->getName();
+    Constant *C = I->getInitializer();
+    // N.B.: We are defaulting to writable strings
+    if (I->hasExternalLinkage()) { 
+      O << "\t.globl " << Name << '\n'
+        << "\t.csect .data[RW],3\n";
+    } else {
+      O << "\t.csect _global.rw_c[RW],3\n";
+    }
+    O << Name << ":\n";
+    emitGlobalConstant(C);
+  }
+
+  // Output labels for globals
+  if (M.gbegin() != M.gend()) O << "\t.toc\n";
+  for (Module::const_giterator I = M.gbegin(), E = M.gend(); I != E; ++I) {
+    const GlobalVariable *GV = I;
+    // Do not output labels for unused variables
+    if (GV->isExternal() && GV->use_begin() == GV->use_end())
+      continue;
+
+    std::string Name = GV->getName();
+    std::string Label = "LC.." + utostr(LabelNumber++);
+    GVToLabelMap[GV] = Label;
+    O << Label << ":\n"
+      << "\t.tc " << Name << "[TC]," << Name;
+    if (GV->isExternal()) O << "[RW]";
+    O << '\n';
+  }
+
+  Mang = new Mangler(M, true);
+  return false; // success
+}
+
+bool Printer::doFinalization(Module &M) {
+  const TargetData &TD = TM.getTargetData();
+  // Print out module-level global variables
+  for (Module::const_giterator I = M.gbegin(), E = M.gend(); I != E; ++I) {
+    if (I->hasInitializer() || I->hasExternalLinkage())
+      continue;
+
+    std::string Name = I->getName();
+    if (I->hasInternalLinkage()) {
+      O << "\t.lcomm " << Name << ",16,_global.bss_c";
+    } else {
+      O << "\t.comm " << Name << "," << TD.getTypeSize(I->getType())
+        << "," << log2((unsigned)TD.getTypeAlignment(I->getType()));
+    }
+    O << "\t\t# ";
+    WriteAsOperand(O, I, true, true, &M);
+    O << "\n";
+  }
+
+  O << "_section_.text:\n"
+    << "\t.csect .data[RW],3\n"
+    << "\t.llong _section_.text\n";
+
+  delete Mang;
+  return false; // success
+}
+
+} // End llvm namespace