It's not necessary to do rounding for alloca operations when the requested
alignment is equal to the stack alignment.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@40004 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/PowerPC/PPCAsmPrinter.cpp b/lib/Target/PowerPC/PPCAsmPrinter.cpp
new file mode 100644
index 0000000..2880196
--- /dev/null
+++ b/lib/Target/PowerPC/PPCAsmPrinter.cpp
@@ -0,0 +1,1101 @@
+//===-- PPCAsmPrinter.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'.
+//
+// Documentation at http://developer.apple.com/documentation/DeveloperTools/
+// Reference/Assembler/ASMIntroduction/chapter_1_section_1.html
+//
+//===----------------------------------------------------------------------===//
+
+#define DEBUG_TYPE "asmprinter"
+#include "PPC.h"
+#include "PPCPredicates.h"
+#include "PPCTargetMachine.h"
+#include "PPCSubtarget.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/DwarfWriter.h"
+#include "llvm/CodeGen/MachineModuleInfo.h"
+#include "llvm/CodeGen/MachineFunctionPass.h"
+#include "llvm/CodeGen/MachineInstr.h"
+#include "llvm/Support/Mangler.h"
+#include "llvm/Support/MathExtras.h"
+#include "llvm/Support/CommandLine.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/Support/Compiler.h"
+#include "llvm/Target/TargetAsmInfo.h"
+#include "llvm/Target/MRegisterInfo.h"
+#include "llvm/Target/TargetInstrInfo.h"
+#include "llvm/Target/TargetOptions.h"
+#include "llvm/ADT/Statistic.h"
+#include "llvm/ADT/StringExtras.h"
+#include <set>
+using namespace llvm;
+
+STATISTIC(EmittedInsts, "Number of machine instrs printed");
+
+namespace {
+  struct VISIBILITY_HIDDEN PPCAsmPrinter : public AsmPrinter {
+    std::set<std::string> FnStubs, GVStubs;
+    const PPCSubtarget &Subtarget;
+
+    PPCAsmPrinter(std::ostream &O, TargetMachine &TM, const TargetAsmInfo *T)
+      : AsmPrinter(O, TM, T), Subtarget(TM.getSubtarget<PPCSubtarget>()) {
+    }
+
+    virtual const char *getPassName() const {
+      return "PowerPC Assembly Printer";
+    }
+
+    PPCTargetMachine &getTM() {
+      return static_cast<PPCTargetMachine&>(TM);
+    }
+
+    unsigned enumRegToMachineReg(unsigned enumReg) {
+      switch (enumReg) {
+      default: assert(0 && "Unhandled register!"); break;
+      case PPC::CR0:  return  0;
+      case PPC::CR1:  return  1;
+      case PPC::CR2:  return  2;
+      case PPC::CR3:  return  3;
+      case PPC::CR4:  return  4;
+      case PPC::CR5:  return  5;
+      case PPC::CR6:  return  6;
+      case PPC::CR7:  return  7;
+      }
+      abort();
+    }
+
+    /// printInstruction - This method is automatically generated by tablegen
+    /// from the instruction set description.  This method returns true if the
+    /// machine instruction was sufficiently described to print it, otherwise it
+    /// returns false.
+    bool printInstruction(const MachineInstr *MI);
+
+    void printMachineInstruction(const MachineInstr *MI);
+    void printOp(const MachineOperand &MO);
+    
+    /// stripRegisterPrefix - This method strips the character prefix from a
+    /// register name so that only the number is left.  Used by for linux asm.
+    const char *stripRegisterPrefix(const char *RegName) {
+      switch (RegName[0]) {
+      case 'r':
+      case 'f':
+      case 'v': return RegName + 1;
+      case 'c': if (RegName[1] == 'r') return RegName + 2;
+      }
+       
+      return RegName;
+    }
+    
+    /// printRegister - Print register according to target requirements.
+    ///
+    void printRegister(const MachineOperand &MO, bool R0AsZero) {
+      unsigned RegNo = MO.getReg();
+      assert(MRegisterInfo::isPhysicalRegister(RegNo) && "Not physreg??");
+      
+      // If we should use 0 for R0.
+      if (R0AsZero && RegNo == PPC::R0) {
+        O << "0";
+        return;
+      }
+      
+      const char *RegName = TM.getRegisterInfo()->get(RegNo).Name;
+      // Linux assembler (Others?) does not take register mnemonics.
+      // FIXME - What about special registers used in mfspr/mtspr?
+      if (!Subtarget.isDarwin()) RegName = stripRegisterPrefix(RegName);
+      O << RegName;
+    }
+
+    void printOperand(const MachineInstr *MI, unsigned OpNo) {
+      const MachineOperand &MO = MI->getOperand(OpNo);
+      if (MO.isRegister()) {
+        printRegister(MO, false);
+      } else if (MO.isImmediate()) {
+        O << MO.getImmedValue();
+      } else {
+        printOp(MO);
+      }
+    }
+    
+    bool PrintAsmOperand(const MachineInstr *MI, unsigned OpNo,
+                         unsigned AsmVariant, const char *ExtraCode);
+    bool PrintAsmMemoryOperand(const MachineInstr *MI, unsigned OpNo,
+                               unsigned AsmVariant, const char *ExtraCode);
+    
+    
+    void printS5ImmOperand(const MachineInstr *MI, unsigned OpNo) {
+      char value = MI->getOperand(OpNo).getImmedValue();
+      value = (value << (32-5)) >> (32-5);
+      O << (int)value;
+    }
+    void printU5ImmOperand(const MachineInstr *MI, unsigned OpNo) {
+      unsigned char value = MI->getOperand(OpNo).getImmedValue();
+      assert(value <= 31 && "Invalid u5imm argument!");
+      O << (unsigned int)value;
+    }
+    void printU6ImmOperand(const MachineInstr *MI, unsigned OpNo) {
+      unsigned char value = MI->getOperand(OpNo).getImmedValue();
+      assert(value <= 63 && "Invalid u6imm argument!");
+      O << (unsigned int)value;
+    }
+    void printS16ImmOperand(const MachineInstr *MI, unsigned OpNo) {
+      O << (short)MI->getOperand(OpNo).getImmedValue();
+    }
+    void printU16ImmOperand(const MachineInstr *MI, unsigned OpNo) {
+      O << (unsigned short)MI->getOperand(OpNo).getImmedValue();
+    }
+    void printS16X4ImmOperand(const MachineInstr *MI, unsigned OpNo) {
+      if (MI->getOperand(OpNo).isImmediate()) {
+        O << (short)(MI->getOperand(OpNo).getImmedValue()*4);
+      } else {
+        O << "lo16(";
+        printOp(MI->getOperand(OpNo));
+        if (TM.getRelocationModel() == Reloc::PIC_)
+          O << "-\"L" << getFunctionNumber() << "$pb\")";
+        else
+          O << ')';
+      }
+    }
+    void printBranchOperand(const MachineInstr *MI, unsigned OpNo) {
+      // Branches can take an immediate operand.  This is used by the branch
+      // selection pass to print $+8, an eight byte displacement from the PC.
+      if (MI->getOperand(OpNo).isImmediate()) {
+        O << "$+" << MI->getOperand(OpNo).getImmedValue()*4;
+      } else {
+        printOp(MI->getOperand(OpNo));
+      }
+    }
+    void printCallOperand(const MachineInstr *MI, unsigned OpNo) {
+      const MachineOperand &MO = MI->getOperand(OpNo);
+      if (TM.getRelocationModel() != Reloc::Static) {
+        if (MO.getType() == MachineOperand::MO_GlobalAddress) {
+          GlobalValue *GV = MO.getGlobal();
+          if (((GV->isDeclaration() || GV->hasWeakLinkage() ||
+                GV->hasLinkOnceLinkage()))) {
+            // Dynamically-resolved functions need a stub for the function.
+            std::string Name = Mang->getValueName(GV);
+            FnStubs.insert(Name);
+            O << "L" << Name << "$stub";
+            if (GV->hasExternalWeakLinkage())
+              ExtWeakSymbols.insert(GV);
+            return;
+          }
+        }
+        if (MO.getType() == MachineOperand::MO_ExternalSymbol) {
+          std::string Name(TAI->getGlobalPrefix()); Name += MO.getSymbolName();
+          FnStubs.insert(Name);
+          O << "L" << Name << "$stub";
+          return;
+        }
+      }
+      
+      printOp(MI->getOperand(OpNo));
+    }
+    void printAbsAddrOperand(const MachineInstr *MI, unsigned OpNo) {
+     O << (int)MI->getOperand(OpNo).getImmedValue()*4;
+    }
+    void printPICLabel(const MachineInstr *MI, unsigned OpNo) {
+      O << "\"L" << getFunctionNumber() << "$pb\"\n";
+      O << "\"L" << getFunctionNumber() << "$pb\":";
+    }
+    void printSymbolHi(const MachineInstr *MI, unsigned OpNo) {
+      if (MI->getOperand(OpNo).isImmediate()) {
+        printS16ImmOperand(MI, OpNo);
+      } else {
+        if (Subtarget.isDarwin()) O << "ha16(";
+        printOp(MI->getOperand(OpNo));
+        if (TM.getRelocationModel() == Reloc::PIC_)
+          O << "-\"L" << getFunctionNumber() << "$pb\"";
+        if (Subtarget.isDarwin())
+          O << ')';
+        else
+          O << "@ha";
+      }
+    }
+    void printSymbolLo(const MachineInstr *MI, unsigned OpNo) {
+      if (MI->getOperand(OpNo).isImmediate()) {
+        printS16ImmOperand(MI, OpNo);
+      } else {
+        if (Subtarget.isDarwin()) O << "lo16(";
+        printOp(MI->getOperand(OpNo));
+        if (TM.getRelocationModel() == Reloc::PIC_)
+          O << "-\"L" << getFunctionNumber() << "$pb\"";
+        if (Subtarget.isDarwin())
+          O << ')';
+        else
+          O << "@l";
+      }
+    }
+    void printcrbitm(const MachineInstr *MI, unsigned OpNo) {
+      unsigned CCReg = MI->getOperand(OpNo).getReg();
+      unsigned RegNo = enumRegToMachineReg(CCReg);
+      O << (0x80 >> RegNo);
+    }
+    // The new addressing mode printers.
+    void printMemRegImm(const MachineInstr *MI, unsigned OpNo) {
+      printSymbolLo(MI, OpNo);
+      O << '(';
+      if (MI->getOperand(OpNo+1).isRegister() && 
+          MI->getOperand(OpNo+1).getReg() == PPC::R0)
+        O << "0";
+      else
+        printOperand(MI, OpNo+1);
+      O << ')';
+    }
+    void printMemRegImmShifted(const MachineInstr *MI, unsigned OpNo) {
+      if (MI->getOperand(OpNo).isImmediate())
+        printS16X4ImmOperand(MI, OpNo);
+      else 
+        printSymbolLo(MI, OpNo);
+      O << '(';
+      if (MI->getOperand(OpNo+1).isRegister() && 
+          MI->getOperand(OpNo+1).getReg() == PPC::R0)
+        O << "0";
+      else
+        printOperand(MI, OpNo+1);
+      O << ')';
+    }
+    
+    void printMemRegReg(const MachineInstr *MI, unsigned OpNo) {
+      // When used as the base register, r0 reads constant zero rather than
+      // the value contained in the register.  For this reason, the darwin
+      // assembler requires that we print r0 as 0 (no r) when used as the base.
+      const MachineOperand &MO = MI->getOperand(OpNo);
+      printRegister(MO, true);
+      O << ", ";
+      printOperand(MI, OpNo+1);
+    }
+    
+    void printPredicateOperand(const MachineInstr *MI, unsigned OpNo, 
+                               const char *Modifier);
+    
+    virtual bool runOnMachineFunction(MachineFunction &F) = 0;
+    virtual bool doFinalization(Module &M) = 0;
+
+    virtual void EmitExternalGlobal(const GlobalVariable *GV);
+  };
+
+  /// LinuxAsmPrinter - PowerPC assembly printer, customized for Linux
+  struct VISIBILITY_HIDDEN LinuxAsmPrinter : public PPCAsmPrinter {
+
+    DwarfWriter DW;
+
+    LinuxAsmPrinter(std::ostream &O, PPCTargetMachine &TM,
+                    const TargetAsmInfo *T)
+      : PPCAsmPrinter(O, TM, T), DW(O, this, T) {
+    }
+
+    virtual const char *getPassName() const {
+      return "Linux PPC Assembly Printer";
+    }
+
+    bool runOnMachineFunction(MachineFunction &F);
+    bool doInitialization(Module &M);
+    bool doFinalization(Module &M);
+    
+    void getAnalysisUsage(AnalysisUsage &AU) const {
+      AU.setPreservesAll();
+      AU.addRequired<MachineModuleInfo>();
+      PPCAsmPrinter::getAnalysisUsage(AU);
+    }
+
+    /// getSectionForFunction - Return the section that we should emit the
+    /// specified function body into.
+    virtual std::string getSectionForFunction(const Function &F) const;
+  };
+
+  /// DarwinAsmPrinter - PowerPC assembly printer, customized for Darwin/Mac OS
+  /// X
+  struct VISIBILITY_HIDDEN DarwinAsmPrinter : public PPCAsmPrinter {
+  
+    DwarfWriter DW;
+
+    DarwinAsmPrinter(std::ostream &O, PPCTargetMachine &TM,
+                     const TargetAsmInfo *T)
+      : PPCAsmPrinter(O, TM, T), DW(O, this, T) {
+    }
+
+    virtual const char *getPassName() const {
+      return "Darwin PPC Assembly Printer";
+    }
+    
+    bool runOnMachineFunction(MachineFunction &F);
+    bool doInitialization(Module &M);
+    bool doFinalization(Module &M);
+    
+    void getAnalysisUsage(AnalysisUsage &AU) const {
+      AU.setPreservesAll();
+      AU.addRequired<MachineModuleInfo>();
+      PPCAsmPrinter::getAnalysisUsage(AU);
+    }
+
+    /// getSectionForFunction - Return the section that we should emit the
+    /// specified function body into.
+    virtual std::string getSectionForFunction(const Function &F) const;
+  };
+} // end of anonymous namespace
+
+// Include the auto-generated portion of the assembly writer
+#include "PPCGenAsmWriter.inc"
+
+void PPCAsmPrinter::printOp(const MachineOperand &MO) {
+  switch (MO.getType()) {
+  case MachineOperand::MO_Immediate:
+    cerr << "printOp() does not handle immediate values\n";
+    abort();
+    return;
+
+  case MachineOperand::MO_MachineBasicBlock:
+    printBasicBlockLabel(MO.getMachineBasicBlock());
+    return;
+  case MachineOperand::MO_JumpTableIndex:
+    O << TAI->getPrivateGlobalPrefix() << "JTI" << getFunctionNumber()
+      << '_' << MO.getJumpTableIndex();
+    // FIXME: PIC relocation model
+    return;
+  case MachineOperand::MO_ConstantPoolIndex:
+    O << TAI->getPrivateGlobalPrefix() << "CPI" << getFunctionNumber()
+      << '_' << MO.getConstantPoolIndex();
+    return;
+  case MachineOperand::MO_ExternalSymbol:
+    // Computing the address of an external symbol, not calling it.
+    if (TM.getRelocationModel() != Reloc::Static) {
+      std::string Name(TAI->getGlobalPrefix()); Name += MO.getSymbolName();
+      GVStubs.insert(Name);
+      O << "L" << Name << "$non_lazy_ptr";
+      return;
+    }
+    O << TAI->getGlobalPrefix() << MO.getSymbolName();
+    return;
+  case MachineOperand::MO_GlobalAddress: {
+    // Computing the address of a global symbol, not calling it.
+    GlobalValue *GV = MO.getGlobal();
+    std::string Name = Mang->getValueName(GV);
+
+    // External or weakly linked global variables need non-lazily-resolved stubs
+    if (TM.getRelocationModel() != Reloc::Static) {
+      if (((GV->isDeclaration() || GV->hasWeakLinkage() ||
+            GV->hasLinkOnceLinkage()))) {
+        GVStubs.insert(Name);
+        O << "L" << Name << "$non_lazy_ptr";
+        return;
+      }
+    }
+    O << Name;
+    
+    if (MO.getOffset() > 0)
+      O << "+" << MO.getOffset();
+    else if (MO.getOffset() < 0)
+      O << MO.getOffset();
+    
+    if (GV->hasExternalWeakLinkage())
+      ExtWeakSymbols.insert(GV);
+    return;
+  }
+
+  default:
+    O << "<unknown operand type: " << MO.getType() << ">";
+    return;
+  }
+}
+
+/// EmitExternalGlobal - In this case we need to use the indirect symbol.
+///
+void PPCAsmPrinter::EmitExternalGlobal(const GlobalVariable *GV) {
+  std::string Name = getGlobalLinkName(GV);
+  if (TM.getRelocationModel() != Reloc::Static) {
+    GVStubs.insert(Name);
+    O << "L" << Name << "$non_lazy_ptr";
+    return;
+  }
+  O << Name;
+}
+
+/// PrintAsmOperand - Print out an operand for an inline asm expression.
+///
+bool PPCAsmPrinter::PrintAsmOperand(const MachineInstr *MI, unsigned OpNo,
+                                    unsigned AsmVariant, 
+                                    const char *ExtraCode) {
+  // Does this asm operand have a single letter operand modifier?
+  if (ExtraCode && ExtraCode[0]) {
+    if (ExtraCode[1] != 0) return true; // Unknown modifier.
+    
+    switch (ExtraCode[0]) {
+    default: return true;  // Unknown modifier.
+    case 'c': // Don't print "$" before a global var name or constant.
+      // PPC never has a prefix.
+      printOperand(MI, OpNo);
+      return false;
+    case 'L': // Write second word of DImode reference.  
+      // Verify that this operand has two consecutive registers.
+      if (!MI->getOperand(OpNo).isRegister() ||
+          OpNo+1 == MI->getNumOperands() ||
+          !MI->getOperand(OpNo+1).isRegister())
+        return true;
+      ++OpNo;   // Return the high-part.
+      break;
+    case 'I':
+      // Write 'i' if an integer constant, otherwise nothing.  Used to print
+      // addi vs add, etc.
+      if (MI->getOperand(OpNo).isImm())
+        O << "i";
+      return false;
+    }
+  }
+  
+  printOperand(MI, OpNo);
+  return false;
+}
+
+bool PPCAsmPrinter::PrintAsmMemoryOperand(const MachineInstr *MI, unsigned OpNo,
+                                          unsigned AsmVariant, 
+                                          const char *ExtraCode) {
+  if (ExtraCode && ExtraCode[0])
+    return true; // Unknown modifier.
+  if (MI->getOperand(OpNo).isRegister())
+    printMemRegReg(MI, OpNo);
+  else
+    printMemRegImm(MI, OpNo);
+  return false;
+}
+
+void PPCAsmPrinter::printPredicateOperand(const MachineInstr *MI, unsigned OpNo, 
+                                          const char *Modifier) {
+  assert(Modifier && "Must specify 'cc' or 'reg' as predicate op modifier!");
+  unsigned Code = MI->getOperand(OpNo).getImm();
+  if (!strcmp(Modifier, "cc")) {
+    switch ((PPC::Predicate)Code) {
+    case PPC::PRED_ALWAYS: return; // Don't print anything for always.
+    case PPC::PRED_LT: O << "lt"; return;
+    case PPC::PRED_LE: O << "le"; return;
+    case PPC::PRED_EQ: O << "eq"; return;
+    case PPC::PRED_GE: O << "ge"; return;
+    case PPC::PRED_GT: O << "gt"; return;
+    case PPC::PRED_NE: O << "ne"; return;
+    case PPC::PRED_UN: O << "un"; return;
+    case PPC::PRED_NU: O << "nu"; return;
+    }
+      
+  } else {
+    assert(!strcmp(Modifier, "reg") &&
+           "Need to specify 'cc' or 'reg' as predicate op modifier!");
+    // Don't print the register for 'always'.
+    if (Code == PPC::PRED_ALWAYS) return;
+    printOperand(MI, OpNo+1);
+  }
+}
+
+
+/// printMachineInstruction -- Print out a single PowerPC MI in Darwin syntax to
+/// the current output stream.
+///
+void PPCAsmPrinter::printMachineInstruction(const MachineInstr *MI) {
+  ++EmittedInsts;
+
+  // Check for slwi/srwi mnemonics.
+  if (MI->getOpcode() == PPC::RLWINM) {
+    bool FoundMnemonic = false;
+    unsigned char SH = MI->getOperand(2).getImmedValue();
+    unsigned char MB = MI->getOperand(3).getImmedValue();
+    unsigned char ME = MI->getOperand(4).getImmedValue();
+    if (SH <= 31 && MB == 0 && ME == (31-SH)) {
+      O << "slwi "; FoundMnemonic = true;
+    }
+    if (SH <= 31 && MB == (32-SH) && ME == 31) {
+      O << "srwi "; FoundMnemonic = true;
+      SH = 32-SH;
+    }
+    if (FoundMnemonic) {
+      printOperand(MI, 0);
+      O << ", ";
+      printOperand(MI, 1);
+      O << ", " << (unsigned int)SH << "\n";
+      return;
+    }
+  } else if (MI->getOpcode() == PPC::OR || MI->getOpcode() == PPC::OR8) {
+    if (MI->getOperand(1).getReg() == MI->getOperand(2).getReg()) {
+      O << "mr ";
+      printOperand(MI, 0);
+      O << ", ";
+      printOperand(MI, 1);
+      O << "\n";
+      return;
+    }
+  } else if (MI->getOpcode() == PPC::RLDICR) {
+    unsigned char SH = MI->getOperand(2).getImmedValue();
+    unsigned char ME = MI->getOperand(3).getImmedValue();
+    // rldicr RA, RS, SH, 63-SH == sldi RA, RS, SH
+    if (63-SH == ME) {
+      O << "sldi ";
+      printOperand(MI, 0);
+      O << ", ";
+      printOperand(MI, 1);
+      O << ", " << (unsigned int)SH << "\n";
+      return;
+    }
+  }
+
+  if (printInstruction(MI))
+    return; // Printer was automatically generated
+
+  assert(0 && "Unhandled instruction in asm writer!");
+  abort();
+  return;
+}
+
+/// runOnMachineFunction - This uses the printMachineInstruction()
+/// method to print assembly for each instruction.
+///
+bool LinuxAsmPrinter::runOnMachineFunction(MachineFunction &MF) {
+  DW.SetModuleInfo(&getAnalysis<MachineModuleInfo>());
+
+  SetupMachineFunction(MF);
+  O << "\n\n";
+  
+  // Print out constants referenced by the function
+  EmitConstantPool(MF.getConstantPool());
+
+  // Print out labels for the function.
+  const Function *F = MF.getFunction();
+  SwitchToTextSection(getSectionForFunction(*F).c_str(), F);
+  
+  switch (F->getLinkage()) {
+  default: assert(0 && "Unknown linkage type!");
+  case Function::InternalLinkage:  // Symbols default to internal.
+    break;
+  case Function::ExternalLinkage:
+    O << "\t.global\t" << CurrentFnName << '\n'
+      << "\t.type\t" << CurrentFnName << ", @function\n";
+    break;
+  case Function::WeakLinkage:
+  case Function::LinkOnceLinkage:
+    O << "\t.global\t" << CurrentFnName << '\n';
+    O << "\t.weak\t" << CurrentFnName << '\n';
+    break;
+  }
+  
+  if (F->hasHiddenVisibility())
+    if (const char *Directive = TAI->getHiddenDirective())
+      O << Directive << CurrentFnName << "\n";
+  
+  EmitAlignment(2, F);
+  O << CurrentFnName << ":\n";
+
+  // Emit pre-function debug information.
+  DW.BeginFunction(&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 (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";
+      printMachineInstruction(II);
+    }
+  }
+
+  O << "\t.size\t" << CurrentFnName << ",.-" << CurrentFnName << "\n";
+
+  // Print out jump tables referenced by the function.
+  EmitJumpTableInfo(MF.getJumpTableInfo(), MF);
+  
+  // Emit post-function debug information.
+  DW.EndFunction();
+  
+  // We didn't modify anything.
+  return false;
+}
+
+bool LinuxAsmPrinter::doInitialization(Module &M) {
+  AsmPrinter::doInitialization(M);
+  
+  // GNU as handles section names wrapped in quotes
+  Mang->setUseQuotes(true);
+
+  SwitchToTextSection(TAI->getTextSection());
+  
+  // Emit initial debug information.
+  DW.BeginModule(&M);
+  return false;
+}
+
+bool LinuxAsmPrinter::doFinalization(Module &M) {
+  const TargetData *TD = TM.getTargetData();
+
+  // Print out module-level global variables here.
+  for (Module::const_global_iterator I = M.global_begin(), E = M.global_end();
+       I != E; ++I) {
+    if (!I->hasInitializer()) continue;   // External global require no code
+    
+    // Check to see if this is a special global used by LLVM, if so, emit it.
+    if (EmitSpecialLLVMGlobal(I))
+      continue;
+
+    std::string name = Mang->getValueName(I);
+
+    if (I->hasHiddenVisibility())
+      if (const char *Directive = TAI->getHiddenDirective())
+        O << Directive << name << "\n";
+    
+    Constant *C = I->getInitializer();
+    unsigned Size = TD->getTypeSize(C->getType());
+    unsigned Align = TD->getPreferredAlignmentLog(I);
+
+    if (C->isNullValue() && /* FIXME: Verify correct */
+        (I->hasInternalLinkage() || I->hasWeakLinkage() ||
+         I->hasLinkOnceLinkage() ||
+         (I->hasExternalLinkage() && !I->hasSection()))) {
+      if (Size == 0) Size = 1;   // .comm Foo, 0 is undefined, avoid it.
+      if (I->hasExternalLinkage()) {
+        O << "\t.global " << name << '\n';
+        O << "\t.type " << name << ", @object\n";
+        //O << "\t.zerofill __DATA, __common, " << name << ", "
+        //  << Size << ", " << Align;
+      } else if (I->hasInternalLinkage()) {
+        SwitchToDataSection("\t.data", I);
+        O << TAI->getLCOMMDirective() << name << "," << Size;
+      } else {
+        SwitchToDataSection("\t.data", I);
+        O << ".comm " << name << "," << Size;
+      }
+      O << "\t\t" << TAI->getCommentString() << " '" << I->getName() << "'\n";
+    } else {
+      switch (I->getLinkage()) {
+      case GlobalValue::LinkOnceLinkage:
+      case GlobalValue::WeakLinkage:
+        O << "\t.global " << name << '\n'
+          << "\t.type " << name << ", @object\n"
+          << "\t.weak " << name << '\n';
+        SwitchToDataSection("\t.data", I);
+        break;
+      case GlobalValue::AppendingLinkage:
+        // FIXME: appending linkage variables should go into a section of
+        // their name or something.  For now, just emit them as external.
+      case GlobalValue::ExternalLinkage:
+        // If external or appending, declare as a global symbol
+        O << "\t.global " << name << "\n"
+          << "\t.type " << name << ", @object\n";
+        // FALL THROUGH
+      case GlobalValue::InternalLinkage:
+        if (I->isConstant()) {
+          const ConstantArray *CVA = dyn_cast<ConstantArray>(C);
+          if (TAI->getCStringSection() && CVA && CVA->isCString()) {
+            SwitchToDataSection(TAI->getCStringSection(), I);
+            break;
+          }
+        }
+
+        // FIXME: special handling for ".ctors" & ".dtors" sections
+        if (I->hasSection() &&
+            (I->getSection() == ".ctors" ||
+             I->getSection() == ".dtors")) {
+          std::string SectionName = ".section " + I->getSection()
+                                                + ",\"aw\",@progbits";
+          SwitchToDataSection(SectionName.c_str());
+        } else {
+          if (I->isConstant() && TAI->getReadOnlySection())
+            SwitchToDataSection(TAI->getReadOnlySection(), I);
+          else
+            SwitchToDataSection(TAI->getDataSection(), I);
+        }
+        break;
+      default:
+        cerr << "Unknown linkage type!";
+        abort();
+      }
+
+      EmitAlignment(Align, I);
+      O << name << ":\t\t\t\t" << TAI->getCommentString() << " '"
+        << I->getName() << "'\n";
+
+      // If the initializer is a extern weak symbol, remember to emit the weak
+      // reference!
+      if (const GlobalValue *GV = dyn_cast<GlobalValue>(C))
+        if (GV->hasExternalWeakLinkage())
+          ExtWeakSymbols.insert(GV);
+
+      EmitGlobalConstant(C);
+      O << '\n';
+    }
+  }
+
+  // TODO
+
+  // Emit initial debug information.
+  DW.EndModule();
+
+  AsmPrinter::doFinalization(M);
+  return false; // success
+}
+
+std::string LinuxAsmPrinter::getSectionForFunction(const Function &F) const {
+  switch (F.getLinkage()) {
+  default: assert(0 && "Unknown linkage type!");
+  case Function::ExternalLinkage:
+  case Function::InternalLinkage: return TAI->getTextSection();
+  case Function::WeakLinkage:
+  case Function::LinkOnceLinkage:
+    return ".text";
+  }
+}
+
+std::string DarwinAsmPrinter::getSectionForFunction(const Function &F) const {
+  switch (F.getLinkage()) {
+  default: assert(0 && "Unknown linkage type!");
+  case Function::ExternalLinkage:
+  case Function::InternalLinkage: return TAI->getTextSection();
+  case Function::WeakLinkage:
+  case Function::LinkOnceLinkage:
+    return ".section __TEXT,__textcoal_nt,coalesced,pure_instructions";
+  }
+}
+
+/// runOnMachineFunction - This uses the printMachineInstruction()
+/// method to print assembly for each instruction.
+///
+bool DarwinAsmPrinter::runOnMachineFunction(MachineFunction &MF) {
+  DW.SetModuleInfo(&getAnalysis<MachineModuleInfo>());
+
+  SetupMachineFunction(MF);
+  O << "\n\n";
+  
+  // Print out constants referenced by the function
+  EmitConstantPool(MF.getConstantPool());
+
+  // Print out labels for the function.
+  const Function *F = MF.getFunction();
+  SwitchToTextSection(getSectionForFunction(*F).c_str(), F);
+  
+  switch (F->getLinkage()) {
+  default: assert(0 && "Unknown linkage type!");
+  case Function::InternalLinkage:  // Symbols default to internal.
+    break;
+  case Function::ExternalLinkage:
+    O << "\t.globl\t" << CurrentFnName << "\n";
+    break;
+  case Function::WeakLinkage:
+  case Function::LinkOnceLinkage:
+    O << "\t.globl\t" << CurrentFnName << "\n";
+    O << "\t.weak_definition\t" << CurrentFnName << "\n";
+    break;
+  }
+  
+  if (F->hasHiddenVisibility())
+    if (const char *Directive = TAI->getHiddenDirective())
+      O << Directive << CurrentFnName << "\n";
+  
+  EmitAlignment(4, F);
+  O << CurrentFnName << ":\n";
+
+  // Emit pre-function debug information.
+  DW.BeginFunction(&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 (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";
+      printMachineInstruction(II);
+    }
+  }
+
+  // Print out jump tables referenced by the function.
+  EmitJumpTableInfo(MF.getJumpTableInfo(), MF);
+  
+  // Emit post-function debug information.
+  DW.EndFunction();
+  
+  // We didn't modify anything.
+  return false;
+}
+
+
+bool DarwinAsmPrinter::doInitialization(Module &M) {
+  static const char *CPUDirectives[] = {
+    "ppc",
+    "ppc601",
+    "ppc602",
+    "ppc603",
+    "ppc7400",
+    "ppc750",
+    "ppc970",
+    "ppc64"
+  };
+
+  unsigned Directive = Subtarget.getDarwinDirective();
+  if (Subtarget.isGigaProcessor() && Directive < PPC::DIR_970)
+    Directive = PPC::DIR_970;
+  if (Subtarget.hasAltivec() && Directive < PPC::DIR_7400)
+    Directive = PPC::DIR_7400;
+  if (Subtarget.isPPC64() && Directive < PPC::DIR_970)
+    Directive = PPC::DIR_64;
+  assert(Directive <= PPC::DIR_64 && "Directive out of range.");
+  O << "\t.machine " << CPUDirectives[Directive] << "\n";
+     
+  AsmPrinter::doInitialization(M);
+  
+  // Darwin wants symbols to be quoted if they have complex names.
+  Mang->setUseQuotes(true);
+  
+  // Prime text sections so they are adjacent.  This reduces the likelihood a
+  // large data or debug section causes a branch to exceed 16M limit.
+  SwitchToTextSection(".section __TEXT,__textcoal_nt,coalesced,"
+                      "pure_instructions");
+  if (TM.getRelocationModel() == Reloc::PIC_) {
+    SwitchToTextSection(".section __TEXT,__picsymbolstub1,symbol_stubs,"
+                          "pure_instructions,32");
+  } else if (TM.getRelocationModel() == Reloc::DynamicNoPIC) {
+    SwitchToTextSection(".section __TEXT,__symbol_stub1,symbol_stubs,"
+                        "pure_instructions,16");
+  }
+  SwitchToTextSection(TAI->getTextSection());
+  
+  // Emit initial debug information.
+  DW.BeginModule(&M);
+  return false;
+}
+
+bool DarwinAsmPrinter::doFinalization(Module &M) {
+  const TargetData *TD = TM.getTargetData();
+
+  // Print out module-level global variables here.
+  for (Module::const_global_iterator I = M.global_begin(), E = M.global_end();
+       I != E; ++I) {
+    if (!I->hasInitializer()) continue;   // External global require no code
+    
+    // Check to see if this is a special global used by LLVM, if so, emit it.
+    if (EmitSpecialLLVMGlobal(I)) {
+      if (TM.getRelocationModel() == Reloc::Static) {
+        if (I->getName() == "llvm.global_ctors")
+          O << ".reference .constructors_used\n";
+        else if (I->getName() == "llvm.global_dtors")
+          O << ".reference .destructors_used\n";
+      }
+      continue;
+    }
+    
+    std::string name = Mang->getValueName(I);
+    
+    if (I->hasHiddenVisibility())
+      if (const char *Directive = TAI->getHiddenDirective())
+        O << Directive << name << "\n";
+    
+    Constant *C = I->getInitializer();
+    const Type *Type = C->getType();
+    unsigned Size = TD->getTypeSize(Type);
+    unsigned Align = TD->getPreferredAlignmentLog(I);
+
+    if (C->isNullValue() && /* FIXME: Verify correct */
+        (I->hasInternalLinkage() || I->hasWeakLinkage() ||
+         I->hasLinkOnceLinkage() ||
+         (I->hasExternalLinkage() && !I->hasSection()))) {
+      if (Size == 0) Size = 1;   // .comm Foo, 0 is undefined, avoid it.
+      if (I->hasExternalLinkage()) {
+        O << "\t.globl " << name << '\n';
+        O << "\t.zerofill __DATA, __common, " << name << ", "
+          << Size << ", " << Align;
+      } else if (I->hasInternalLinkage()) {
+        SwitchToDataSection("\t.data", I);
+        O << TAI->getLCOMMDirective() << name << "," << Size << "," << Align;
+      } else {
+        SwitchToDataSection("\t.data", I);
+        O << ".comm " << name << "," << Size;
+      }
+      O << "\t\t" << TAI->getCommentString() << " '" << I->getName() << "'\n";
+    } else {
+      switch (I->getLinkage()) {
+      case GlobalValue::LinkOnceLinkage:
+      case GlobalValue::WeakLinkage:
+        O << "\t.globl " << name << '\n'
+          << "\t.weak_definition " << name << '\n';
+        SwitchToDataSection(".section __DATA,__datacoal_nt,coalesced", I);
+        break;
+      case GlobalValue::AppendingLinkage:
+        // FIXME: appending linkage variables should go into a section of
+        // their name or something.  For now, just emit them as external.
+      case GlobalValue::ExternalLinkage:
+        // If external or appending, declare as a global symbol
+        O << "\t.globl " << name << "\n";
+        // FALL THROUGH
+      case GlobalValue::InternalLinkage:
+        if (I->isConstant()) {
+          const ConstantArray *CVA = dyn_cast<ConstantArray>(C);
+          if (TAI->getCStringSection() && CVA && CVA->isCString()) {
+            SwitchToDataSection(TAI->getCStringSection(), I);
+            break;
+          }
+        }
+
+        if (!I->isConstant())
+          SwitchToDataSection(TAI->getDataSection(), I);
+        else {
+          // Read-only data.
+          bool HasReloc = C->ContainsRelocations();
+          if (HasReloc &&
+              TM.getRelocationModel() != Reloc::Static)
+            SwitchToDataSection("\t.const_data\n");
+          else if (!HasReloc && Size == 4 &&
+                   TAI->getFourByteConstantSection())
+            SwitchToDataSection(TAI->getFourByteConstantSection(), I);
+          else if (!HasReloc && Size == 8 &&
+                   TAI->getEightByteConstantSection())
+            SwitchToDataSection(TAI->getEightByteConstantSection(), I);
+          else if (!HasReloc && Size == 16 &&
+                   TAI->getSixteenByteConstantSection())
+            SwitchToDataSection(TAI->getSixteenByteConstantSection(), I);
+          else if (TAI->getReadOnlySection())
+            SwitchToDataSection(TAI->getReadOnlySection(), I);
+          else
+            SwitchToDataSection(TAI->getDataSection(), I);
+        }
+        break;
+      default:
+        cerr << "Unknown linkage type!";
+        abort();
+      }
+
+      EmitAlignment(Align, I);
+      O << name << ":\t\t\t\t" << TAI->getCommentString() << " '"
+        << I->getName() << "'\n";
+
+      // If the initializer is a extern weak symbol, remember to emit the weak
+      // reference!
+      if (const GlobalValue *GV = dyn_cast<GlobalValue>(C))
+        if (GV->hasExternalWeakLinkage())
+          ExtWeakSymbols.insert(GV);
+
+      EmitGlobalConstant(C);
+      O << '\n';
+    }
+  }
+
+  bool isPPC64 = TD->getPointerSizeInBits() == 64;
+
+  // Output stubs for dynamically-linked functions
+  if (TM.getRelocationModel() == Reloc::PIC_) {
+    for (std::set<std::string>::iterator i = FnStubs.begin(), e = FnStubs.end();
+         i != e; ++i) {
+      SwitchToTextSection(".section __TEXT,__picsymbolstub1,symbol_stubs,"
+                          "pure_instructions,32");
+      EmitAlignment(4);
+      O << "L" << *i << "$stub:\n";
+      O << "\t.indirect_symbol " << *i << "\n";
+      O << "\tmflr r0\n";
+      O << "\tbcl 20,31,L0$" << *i << "\n";
+      O << "L0$" << *i << ":\n";
+      O << "\tmflr r11\n";
+      O << "\taddis r11,r11,ha16(L" << *i << "$lazy_ptr-L0$" << *i << ")\n";
+      O << "\tmtlr r0\n";
+      if (isPPC64)
+        O << "\tldu r12,lo16(L" << *i << "$lazy_ptr-L0$" << *i << ")(r11)\n";
+      else
+        O << "\tlwzu r12,lo16(L" << *i << "$lazy_ptr-L0$" << *i << ")(r11)\n";
+      O << "\tmtctr r12\n";
+      O << "\tbctr\n";
+      SwitchToDataSection(".lazy_symbol_pointer");
+      O << "L" << *i << "$lazy_ptr:\n";
+      O << "\t.indirect_symbol " << *i << "\n";
+      if (isPPC64)
+        O << "\t.quad dyld_stub_binding_helper\n";
+      else
+        O << "\t.long dyld_stub_binding_helper\n";
+    }
+  } else {
+    for (std::set<std::string>::iterator i = FnStubs.begin(), e = FnStubs.end();
+         i != e; ++i) {
+      SwitchToTextSection(".section __TEXT,__symbol_stub1,symbol_stubs,"
+                          "pure_instructions,16");
+      EmitAlignment(4);
+      O << "L" << *i << "$stub:\n";
+      O << "\t.indirect_symbol " << *i << "\n";
+      O << "\tlis r11,ha16(L" << *i << "$lazy_ptr)\n";
+      if (isPPC64)
+        O << "\tldu r12,lo16(L" << *i << "$lazy_ptr)(r11)\n";
+      else
+        O << "\tlwzu r12,lo16(L" << *i << "$lazy_ptr)(r11)\n";
+      O << "\tmtctr r12\n";
+      O << "\tbctr\n";
+      SwitchToDataSection(".lazy_symbol_pointer");
+      O << "L" << *i << "$lazy_ptr:\n";
+      O << "\t.indirect_symbol " << *i << "\n";
+      if (isPPC64)
+        O << "\t.quad dyld_stub_binding_helper\n";
+      else
+        O << "\t.long dyld_stub_binding_helper\n";
+    }
+  }
+
+  O << "\n";
+
+  // Output stubs for external and common global variables.
+  if (GVStubs.begin() != GVStubs.end()) {
+    SwitchToDataSection(".non_lazy_symbol_pointer");
+    for (std::set<std::string>::iterator I = GVStubs.begin(),
+         E = GVStubs.end(); I != E; ++I) {
+      O << "L" << *I << "$non_lazy_ptr:\n";
+      O << "\t.indirect_symbol " << *I << "\n";
+      if (isPPC64)
+        O << "\t.quad\t0\n";
+      else
+        O << "\t.long\t0\n";
+        
+    }
+  }
+
+  // Emit initial debug information.
+  DW.EndModule();
+
+  // Funny Darwin hack: This flag tells the linker that no global symbols
+  // contain code that falls through to other global symbols (e.g. the obvious
+  // implementation of multiple entry points).  If this doesn't occur, the
+  // linker can safely perform dead code stripping.  Since LLVM never generates
+  // code that does this, it is always safe to set.
+  O << "\t.subsections_via_symbols\n";
+
+  AsmPrinter::doFinalization(M);
+  return false; // success
+}
+
+
+
+/// createPPCAsmPrinterPass - Returns a pass that prints the PPC assembly code
+/// for a MachineFunction to the given output stream, in a format that the
+/// Darwin assembler can deal with.
+///
+FunctionPass *llvm::createPPCAsmPrinterPass(std::ostream &o,
+                                            PPCTargetMachine &tm) {
+  const PPCSubtarget *Subtarget = &tm.getSubtarget<PPCSubtarget>();
+
+  if (Subtarget->isDarwin()) {
+    return new DarwinAsmPrinter(o, tm, tm.getTargetAsmInfo());
+  } else {
+    return new LinuxAsmPrinter(o, tm, tm.getTargetAsmInfo());
+  }
+}
+