PPCAsmPrinter.cpp revision b9ca92661cf145bfb3bd9705e5629fc5f411a42f 
1//===-- PPCAsmPrinter.cpp - Print machine instrs to PowerPC assembly --------=//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file was developed by the LLVM research group and is distributed under
6// the University of Illinois Open Source License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10// This file contains a printer that converts from our internal representation
11// of machine-dependent LLVM code to PowerPC assembly language. This printer is
12// the output mechanism used by `llc'.
13//
14// Documentation at http://developer.apple.com/documentation/DeveloperTools/
15// Reference/Assembler/ASMIntroduction/chapter_1_section_1.html
16//
17//===----------------------------------------------------------------------===//
18
19#define DEBUG_TYPE "asmprinter"
20#include "PPC.h"
21#include "PPCTargetMachine.h"
22#include "PPCSubtarget.h"
23#include "llvm/Constants.h"
24#include "llvm/DerivedTypes.h"
25#include "llvm/Module.h"
26#include "llvm/Assembly/Writer.h"
27#include "llvm/CodeGen/AsmPrinter.h"
28#include "llvm/CodeGen/DwarfWriter.h"
29#include "llvm/CodeGen/MachineDebugInfo.h"
30#include "llvm/CodeGen/MachineFunctionPass.h"
31#include "llvm/CodeGen/MachineInstr.h"
32#include "llvm/Support/Mangler.h"
33#include "llvm/Support/MathExtras.h"
34#include "llvm/Support/CommandLine.h"
35#include "llvm/Support/Debug.h"
36#include "llvm/Support/Visibility.h"
37#include "llvm/Target/MRegisterInfo.h"
38#include "llvm/Target/TargetInstrInfo.h"
39#include "llvm/Target/TargetOptions.h"
40#include "llvm/ADT/Statistic.h"
41#include "llvm/ADT/StringExtras.h"
42#include <iostream>
43#include <set>
44using namespace llvm;
45
46namespace {
47  Statistic<> EmittedInsts("asm-printer", "Number of machine instrs printed");
48
49  class VISIBILITY_HIDDEN PPCAsmPrinter : public AsmPrinter {
50  public:
51    std::set<std::string> FnStubs, GVStubs;
52
53    PPCAsmPrinter(std::ostream &O, TargetMachine &TM)
54      : AsmPrinter(O, TM) {}
55
56    virtual const char *getPassName() const {
57      return "PowerPC Assembly Printer";
58    }
59
60    PPCTargetMachine &getTM() {
61      return static_cast<PPCTargetMachine&>(TM);
62    }
63
64    unsigned enumRegToMachineReg(unsigned enumReg) {
65      switch (enumReg) {
66      default: assert(0 && "Unhandled register!"); break;
67      case PPC::CR0:  return  0;
68      case PPC::CR1:  return  1;
69      case PPC::CR2:  return  2;
70      case PPC::CR3:  return  3;
71      case PPC::CR4:  return  4;
72      case PPC::CR5:  return  5;
73      case PPC::CR6:  return  6;
74      case PPC::CR7:  return  7;
75      }
76      abort();
77    }
78
79    /// printInstruction - This method is automatically generated by tablegen
80    /// from the instruction set description.  This method returns true if the
81    /// machine instruction was sufficiently described to print it, otherwise it
82    /// returns false.
83    bool printInstruction(const MachineInstr *MI);
84
85    void printMachineInstruction(const MachineInstr *MI);
86    void printOp(const MachineOperand &MO);
87
88    void printOperand(const MachineInstr *MI, unsigned OpNo) {
89      const MachineOperand &MO = MI->getOperand(OpNo);
90      if (MO.isRegister()) {
91        assert(MRegisterInfo::isPhysicalRegister(MO.getReg())&&"Not physreg??");
92        O << TM.getRegisterInfo()->get(MO.getReg()).Name;
93      } else if (MO.isImmediate()) {
94        O << MO.getImmedValue();
95      } else {
96        printOp(MO);
97      }
98    }
99
100    bool PrintAsmOperand(const MachineInstr *MI, unsigned OpNo,
101                         unsigned AsmVariant, const char *ExtraCode);
102    bool PrintAsmMemoryOperand(const MachineInstr *MI, unsigned OpNo,
103                               unsigned AsmVariant, const char *ExtraCode);
104
105
106    void printS5ImmOperand(const MachineInstr *MI, unsigned OpNo) {
107      char value = MI->getOperand(OpNo).getImmedValue();
108      value = (value << (32-5)) >> (32-5);
109      O << (int)value;
110    }
111    void printU5ImmOperand(const MachineInstr *MI, unsigned OpNo) {
112      unsigned char value = MI->getOperand(OpNo).getImmedValue();
113      assert(value <= 31 && "Invalid u5imm argument!");
114      O << (unsigned int)value;
115    }
116    void printU6ImmOperand(const MachineInstr *MI, unsigned OpNo) {
117      unsigned char value = MI->getOperand(OpNo).getImmedValue();
118      assert(value <= 63 && "Invalid u6imm argument!");
119      O << (unsigned int)value;
120    }
121    void printS16ImmOperand(const MachineInstr *MI, unsigned OpNo) {
122      O << (short)MI->getOperand(OpNo).getImmedValue();
123    }
124    void printU16ImmOperand(const MachineInstr *MI, unsigned OpNo) {
125      O << (unsigned short)MI->getOperand(OpNo).getImmedValue();
126    }
127    void printS16X4ImmOperand(const MachineInstr *MI, unsigned OpNo) {
128      O << (short)(MI->getOperand(OpNo).getImmedValue()*4);
129    }
130    void printBranchOperand(const MachineInstr *MI, unsigned OpNo) {
131      // Branches can take an immediate operand.  This is used by the branch
132      // selection pass to print $+8, an eight byte displacement from the PC.
133      if (MI->getOperand(OpNo).isImmediate()) {
134        O << "$+" << MI->getOperand(OpNo).getImmedValue()*4;
135      } else {
136        printOp(MI->getOperand(OpNo));
137      }
138    }
139    void printCallOperand(const MachineInstr *MI, unsigned OpNo) {
140      const MachineOperand &MO = MI->getOperand(OpNo);
141      if (TM.getRelocationModel() != Reloc::Static) {
142        if (MO.getType() == MachineOperand::MO_GlobalAddress) {
143          GlobalValue *GV = MO.getGlobal();
144          if (((GV->isExternal() || GV->hasWeakLinkage() ||
145                GV->hasLinkOnceLinkage()))) {
146            // Dynamically-resolved functions need a stub for the function.
147            std::string Name = Mang->getValueName(GV);
148            FnStubs.insert(Name);
149            O << "L" << Name << "$stub";
150            return;
151          }
152        }
153        if (MO.getType() == MachineOperand::MO_ExternalSymbol) {
154          std::string Name(GlobalPrefix); Name += MO.getSymbolName();
155          FnStubs.insert(Name);
156          O << "L" << Name << "$stub";
157          return;
158        }
159      }
160
161      printOp(MI->getOperand(OpNo));
162    }
163    void printAbsAddrOperand(const MachineInstr *MI, unsigned OpNo) {
164     O << (int)MI->getOperand(OpNo).getImmedValue()*4;
165    }
166    void printPICLabel(const MachineInstr *MI, unsigned OpNo) {
167      O << "\"L" << getFunctionNumber() << "$pb\"\n";
168      O << "\"L" << getFunctionNumber() << "$pb\":";
169    }
170    void printSymbolHi(const MachineInstr *MI, unsigned OpNo) {
171      if (MI->getOperand(OpNo).isImmediate()) {
172        printS16ImmOperand(MI, OpNo);
173      } else {
174        O << "ha16(";
175        printOp(MI->getOperand(OpNo));
176        if (TM.getRelocationModel() == Reloc::PIC_)
177          O << "-\"L" << getFunctionNumber() << "$pb\")";
178        else
179          O << ')';
180      }
181    }
182    void printSymbolLo(const MachineInstr *MI, unsigned OpNo) {
183      if (MI->getOperand(OpNo).isImmediate()) {
184        printS16ImmOperand(MI, OpNo);
185      } else {
186        O << "lo16(";
187        printOp(MI->getOperand(OpNo));
188        if (TM.getRelocationModel() == Reloc::PIC_)
189          O << "-\"L" << getFunctionNumber() << "$pb\")";
190        else
191          O << ')';
192      }
193    }
194    void printcrbitm(const MachineInstr *MI, unsigned OpNo) {
195      unsigned CCReg = MI->getOperand(OpNo).getReg();
196      unsigned RegNo = enumRegToMachineReg(CCReg);
197      O << (0x80 >> RegNo);
198    }
199    // The new addressing mode printers.
200    void printMemRegImm(const MachineInstr *MI, unsigned OpNo) {
201      printSymbolLo(MI, OpNo);
202      O << '(';
203      if (MI->getOperand(OpNo+1).isRegister() &&
204          MI->getOperand(OpNo+1).getReg() == PPC::R0)
205        O << "0";
206      else
207        printOperand(MI, OpNo+1);
208      O << ')';
209    }
210    void printMemRegImmShifted(const MachineInstr *MI, unsigned OpNo) {
211      if (MI->getOperand(OpNo).isImmediate())
212        printS16X4ImmOperand(MI, OpNo);
213      else
214        printSymbolLo(MI, OpNo);
215      O << '(';
216      if (MI->getOperand(OpNo+1).isRegister() &&
217          MI->getOperand(OpNo+1).getReg() == PPC::R0)
218        O << "0";
219      else
220        printOperand(MI, OpNo+1);
221      O << ')';
222    }
223
224    void printMemRegReg(const MachineInstr *MI, unsigned OpNo) {
225      // When used as the base register, r0 reads constant zero rather than
226      // the value contained in the register.  For this reason, the darwin
227      // assembler requires that we print r0 as 0 (no r) when used as the base.
228      const MachineOperand &MO = MI->getOperand(OpNo);
229      if (MO.getReg() == PPC::R0)
230        O << '0';
231      else
232        O << TM.getRegisterInfo()->get(MO.getReg()).Name;
233      O << ", ";
234      printOperand(MI, OpNo+1);
235    }
236
237    virtual bool runOnMachineFunction(MachineFunction &F) = 0;
238    virtual bool doFinalization(Module &M) = 0;
239
240  };
241
242  /// DarwinDwarfWriter - Dwarf debug info writer customized for Darwin/Mac OS X
243  ///
244  struct VISIBILITY_HIDDEN DarwinDwarfWriter : public DwarfWriter {
245    // Ctor.
246    DarwinDwarfWriter(std::ostream &o, AsmPrinter *ap)
247    : DwarfWriter(o, ap)
248    {
249      needsSet = true;
250      DwarfAbbrevSection = ".section __DWARF,__debug_abbrev";
251      DwarfInfoSection = ".section __DWARF,__debug_info";
252      DwarfLineSection = ".section __DWARF,__debug_line";
253      DwarfFrameSection = ".section __DWARF,__debug_frame";
254      DwarfPubNamesSection = ".section __DWARF,__debug_pubnames";
255      DwarfPubTypesSection = ".section __DWARF,__debug_pubtypes";
256      DwarfStrSection = ".section __DWARF,__debug_str";
257      DwarfLocSection = ".section __DWARF,__debug_loc";
258      DwarfARangesSection = ".section __DWARF,__debug_aranges";
259      DwarfRangesSection = ".section __DWARF,__debug_ranges";
260      DwarfMacInfoSection = ".section __DWARF,__debug_macinfo";
261      TextSection = ".text";
262      DataSection = ".data";
263    }
264  };
265
266  /// DarwinAsmPrinter - PowerPC assembly printer, customized for Darwin/Mac OS
267  /// X
268  struct VISIBILITY_HIDDEN DarwinAsmPrinter : public PPCAsmPrinter {
269
270    DarwinDwarfWriter DW;
271
272    DarwinAsmPrinter(std::ostream &O, PPCTargetMachine &TM)
273      : PPCAsmPrinter(O, TM), DW(O, this) {
274      bool isPPC64 = TM.getSubtargetImpl()->isPPC64();
275      CommentString = ";";
276      GlobalPrefix = "_";
277      PrivateGlobalPrefix = "L";     // Marker for constant pool idxs
278      ZeroDirective = "\t.space\t";  // ".space N" emits N zeros.
279      SetDirective = "\t.set";
280      if (isPPC64)
281        Data64bitsDirective = ".quad\t";       // we can't emit a 64-bit unit
282      else
283        Data64bitsDirective = 0;       // we can't emit a 64-bit unit
284      AlignmentIsInBytes = false;    // Alignment is by power of 2.
285      ConstantPoolSection = "\t.const\t";
286      JumpTableDataSection = ".const";
287      JumpTableTextSection = "\t.text";
288      LCOMMDirective = "\t.lcomm\t";
289      StaticCtorsSection = ".mod_init_func";
290      StaticDtorsSection = ".mod_term_func";
291      InlineAsmStart = "# InlineAsm Start";
292      InlineAsmEnd = "# InlineAsm End";
293    }
294
295    virtual const char *getPassName() const {
296      return "Darwin PPC Assembly Printer";
297    }
298
299    bool runOnMachineFunction(MachineFunction &F);
300    bool doInitialization(Module &M);
301    bool doFinalization(Module &M);
302
303    void getAnalysisUsage(AnalysisUsage &AU) const {
304      AU.setPreservesAll();
305      AU.addRequired<MachineDebugInfo>();
306      PPCAsmPrinter::getAnalysisUsage(AU);
307    }
308
309  };
310} // end of anonymous namespace
311
312/// createDarwinAsmPrinterPass - Returns a pass that prints the PPC assembly
313/// code for a MachineFunction to the given output stream, in a format that the
314/// Darwin assembler can deal with.
315///
316FunctionPass *llvm::createDarwinAsmPrinter(std::ostream &o,
317                                           PPCTargetMachine &tm) {
318  return new DarwinAsmPrinter(o, tm);
319}
320
321// Include the auto-generated portion of the assembly writer
322#include "PPCGenAsmWriter.inc"
323
324void PPCAsmPrinter::printOp(const MachineOperand &MO) {
325  switch (MO.getType()) {
326  case MachineOperand::MO_Immediate:
327    std::cerr << "printOp() does not handle immediate values\n";
328    abort();
329    return;
330
331  case MachineOperand::MO_MachineBasicBlock:
332    printBasicBlockLabel(MO.getMachineBasicBlock());
333    return;
334  case MachineOperand::MO_JumpTableIndex:
335    O << PrivateGlobalPrefix << "JTI" << getFunctionNumber()
336      << '_' << MO.getJumpTableIndex();
337    // FIXME: PIC relocation model
338    return;
339  case MachineOperand::MO_ConstantPoolIndex:
340    O << PrivateGlobalPrefix << "CPI" << getFunctionNumber()
341      << '_' << MO.getConstantPoolIndex();
342    return;
343  case MachineOperand::MO_ExternalSymbol:
344    // Computing the address of an external symbol, not calling it.
345    if (TM.getRelocationModel() != Reloc::Static) {
346      std::string Name(GlobalPrefix); Name += MO.getSymbolName();
347      GVStubs.insert(Name);
348      O << "L" << Name << "$non_lazy_ptr";
349      return;
350    }
351    O << GlobalPrefix << MO.getSymbolName();
352    return;
353  case MachineOperand::MO_GlobalAddress: {
354    // Computing the address of a global symbol, not calling it.
355    GlobalValue *GV = MO.getGlobal();
356    std::string Name = Mang->getValueName(GV);
357    int offset = MO.getOffset();
358
359    // External or weakly linked global variables need non-lazily-resolved stubs
360    if (TM.getRelocationModel() != Reloc::Static) {
361      if (((GV->isExternal() || GV->hasWeakLinkage() ||
362            GV->hasLinkOnceLinkage()))) {
363        GVStubs.insert(Name);
364        O << "L" << Name << "$non_lazy_ptr";
365        return;
366      }
367    }
368
369    O << Name;
370    return;
371  }
372
373  default:
374    O << "<unknown operand type: " << MO.getType() << ">";
375    return;
376  }
377}
378
379/// PrintAsmOperand - Print out an operand for an inline asm expression.
380///
381bool PPCAsmPrinter::PrintAsmOperand(const MachineInstr *MI, unsigned OpNo,
382                                    unsigned AsmVariant,
383                                    const char *ExtraCode) {
384  // Does this asm operand have a single letter operand modifier?
385  if (ExtraCode && ExtraCode[0]) {
386    if (ExtraCode[1] != 0) return true; // Unknown modifier.
387
388    switch (ExtraCode[0]) {
389    default: return true;  // Unknown modifier.
390    case 'L': // Write second word of DImode reference.
391      // Verify that this operand has two consecutive registers.
392      if (!MI->getOperand(OpNo).isRegister() ||
393          OpNo+1 == MI->getNumOperands() ||
394          !MI->getOperand(OpNo+1).isRegister())
395        return true;
396      ++OpNo;   // Return the high-part.
397      break;
398    }
399  }
400
401  printOperand(MI, OpNo);
402  return false;
403}
404
405bool PPCAsmPrinter::PrintAsmMemoryOperand(const MachineInstr *MI, unsigned OpNo,
406                                          unsigned AsmVariant,
407                                          const char *ExtraCode) {
408  if (ExtraCode && ExtraCode[0])
409    return true; // Unknown modifier.
410  printMemRegReg(MI, OpNo);
411  return false;
412}
413
414/// printMachineInstruction -- Print out a single PowerPC MI in Darwin syntax to
415/// the current output stream.
416///
417void PPCAsmPrinter::printMachineInstruction(const MachineInstr *MI) {
418  ++EmittedInsts;
419
420  // Check for slwi/srwi mnemonics.
421  if (MI->getOpcode() == PPC::RLWINM) {
422    bool FoundMnemonic = false;
423    unsigned char SH = MI->getOperand(2).getImmedValue();
424    unsigned char MB = MI->getOperand(3).getImmedValue();
425    unsigned char ME = MI->getOperand(4).getImmedValue();
426    if (SH <= 31 && MB == 0 && ME == (31-SH)) {
427      O << "slwi "; FoundMnemonic = true;
428    }
429    if (SH <= 31 && MB == (32-SH) && ME == 31) {
430      O << "srwi "; FoundMnemonic = true;
431      SH = 32-SH;
432    }
433    if (FoundMnemonic) {
434      printOperand(MI, 0);
435      O << ", ";
436      printOperand(MI, 1);
437      O << ", " << (unsigned int)SH << "\n";
438      return;
439    }
440  } else if (MI->getOpcode() == PPC::OR || MI->getOpcode() == PPC::OR8) {
441    if (MI->getOperand(1).getReg() == MI->getOperand(2).getReg()) {
442      O << "mr ";
443      printOperand(MI, 0);
444      O << ", ";
445      printOperand(MI, 1);
446      O << "\n";
447      return;
448    }
449  }
450
451  if (printInstruction(MI))
452    return; // Printer was automatically generated
453
454  assert(0 && "Unhandled instruction in asm writer!");
455  abort();
456  return;
457}
458
459/// runOnMachineFunction - This uses the printMachineInstruction()
460/// method to print assembly for each instruction.
461///
462bool DarwinAsmPrinter::runOnMachineFunction(MachineFunction &MF) {
463  DW.SetDebugInfo(&getAnalysis<MachineDebugInfo>());
464
465  SetupMachineFunction(MF);
466  O << "\n\n";
467
468  // Print out constants referenced by the function
469  EmitConstantPool(MF.getConstantPool());
470
471  // Print out jump tables referenced by the function
472  EmitJumpTableInfo(MF.getJumpTableInfo());
473
474  // Print out labels for the function.
475  const Function *F = MF.getFunction();
476  switch (F->getLinkage()) {
477  default: assert(0 && "Unknown linkage type!");
478  case Function::InternalLinkage:  // Symbols default to internal.
479    SwitchToTextSection("\t.text", F);
480    break;
481  case Function::ExternalLinkage:
482    SwitchToTextSection("\t.text", F);
483    O << "\t.globl\t" << CurrentFnName << "\n";
484    break;
485  case Function::WeakLinkage:
486  case Function::LinkOnceLinkage:
487    SwitchToTextSection(
488                ".section __TEXT,__textcoal_nt,coalesced,pure_instructions", F);
489    O << "\t.globl\t" << CurrentFnName << "\n";
490    O << "\t.weak_definition\t" << CurrentFnName << "\n";
491    break;
492  }
493  EmitAlignment(4, F);
494  O << CurrentFnName << ":\n";
495
496  // Emit pre-function debug information.
497  DW.BeginFunction(&MF);
498
499  // Print out code for the function.
500  for (MachineFunction::const_iterator I = MF.begin(), E = MF.end();
501       I != E; ++I) {
502    // Print a label for the basic block.
503    if (I != MF.begin()) {
504      printBasicBlockLabel(I, true);
505      O << '\n';
506    }
507    for (MachineBasicBlock::const_iterator II = I->begin(), E = I->end();
508         II != E; ++II) {
509      // Print the assembly for the instruction.
510      O << "\t";
511      printMachineInstruction(II);
512    }
513  }
514
515  // Emit post-function debug information.
516  DW.EndFunction();
517
518  // We didn't modify anything.
519  return false;
520}
521
522
523bool DarwinAsmPrinter::doInitialization(Module &M) {
524  if (TM.getSubtarget<PPCSubtarget>().isGigaProcessor())
525    O << "\t.machine ppc970\n";
526  AsmPrinter::doInitialization(M);
527
528  // Darwin wants symbols to be quoted if they have complex names.
529  Mang->setUseQuotes(true);
530
531  // Emit initial debug information.
532  DW.BeginModule(&M);
533  return false;
534}
535
536bool DarwinAsmPrinter::doFinalization(Module &M) {
537  const TargetData *TD = TM.getTargetData();
538
539  // Print out module-level global variables here.
540  for (Module::const_global_iterator I = M.global_begin(), E = M.global_end();
541       I != E; ++I) {
542    if (!I->hasInitializer()) continue;   // External global require no code
543
544    // Check to see if this is a special global used by LLVM, if so, emit it.
545    if (EmitSpecialLLVMGlobal(I))
546      continue;
547
548    std::string name = Mang->getValueName(I);
549    Constant *C = I->getInitializer();
550    unsigned Size = TD->getTypeSize(C->getType());
551    unsigned Align = getPreferredAlignmentLog(I);
552
553    if (C->isNullValue() && /* FIXME: Verify correct */
554        (I->hasInternalLinkage() || I->hasWeakLinkage() ||
555         I->hasLinkOnceLinkage() ||
556         (I->hasExternalLinkage() && !I->hasSection()))) {
557      if (Size == 0) Size = 1;   // .comm Foo, 0 is undefined, avoid it.
558      if (I->hasExternalLinkage()) {
559        O << "\t.globl " << name << '\n';
560        O << "\t.zerofill __DATA, __common, " << name << ", "
561          << Size << ", " << Align;
562      } else if (I->hasInternalLinkage()) {
563        SwitchToDataSection("\t.data", I);
564        O << LCOMMDirective << name << "," << Size << "," << Align;
565      } else {
566        SwitchToDataSection("\t.data", I);
567        O << ".comm " << name << "," << Size;
568      }
569      O << "\t\t; '" << I->getName() << "'\n";
570    } else {
571      switch (I->getLinkage()) {
572      case GlobalValue::LinkOnceLinkage:
573      case GlobalValue::WeakLinkage:
574        O << "\t.globl " << name << '\n'
575          << "\t.weak_definition " << name << '\n';
576        SwitchToDataSection(".section __DATA,__datacoal_nt,coalesced", I);
577        break;
578      case GlobalValue::AppendingLinkage:
579        // FIXME: appending linkage variables should go into a section of
580        // their name or something.  For now, just emit them as external.
581      case GlobalValue::ExternalLinkage:
582        // If external or appending, declare as a global symbol
583        O << "\t.globl " << name << "\n";
584        // FALL THROUGH
585      case GlobalValue::InternalLinkage:
586        SwitchToDataSection("\t.data", I);
587        break;
588      default:
589        std::cerr << "Unknown linkage type!";
590        abort();
591      }
592
593      EmitAlignment(Align, I);
594      O << name << ":\t\t\t\t; '" << I->getName() << "'\n";
595      EmitGlobalConstant(C);
596      O << '\n';
597    }
598  }
599
600  bool isPPC64 = TD->getPointerSizeInBits() == 64;
601
602  // Output stubs for dynamically-linked functions
603  if (TM.getRelocationModel() == Reloc::PIC_) {
604    for (std::set<std::string>::iterator i = FnStubs.begin(), e = FnStubs.end();
605         i != e; ++i) {
606      SwitchToTextSection(".section __TEXT,__picsymbolstub1,symbol_stubs,"
607                          "pure_instructions,32", 0);
608      EmitAlignment(4);
609      O << "L" << *i << "$stub:\n";
610      O << "\t.indirect_symbol " << *i << "\n";
611      O << "\tmflr r0\n";
612      O << "\tbcl 20,31,L0$" << *i << "\n";
613      O << "L0$" << *i << ":\n";
614      O << "\tmflr r11\n";
615      O << "\taddis r11,r11,ha16(L" << *i << "$lazy_ptr-L0$" << *i << ")\n";
616      O << "\tmtlr r0\n";
617      if (isPPC64)
618        O << "\tldu r12,lo16(L" << *i << "$lazy_ptr-L0$" << *i << ")(r11)\n";
619      else
620        O << "\tlwzu r12,lo16(L" << *i << "$lazy_ptr-L0$" << *i << ")(r11)\n";
621      O << "\tmtctr r12\n";
622      O << "\tbctr\n";
623      SwitchToDataSection(".lazy_symbol_pointer", 0);
624      O << "L" << *i << "$lazy_ptr:\n";
625      O << "\t.indirect_symbol " << *i << "\n";
626      if (isPPC64)
627        O << "\t.quad dyld_stub_binding_helper\n";
628      else
629        O << "\t.long dyld_stub_binding_helper\n";
630    }
631  } else {
632    for (std::set<std::string>::iterator i = FnStubs.begin(), e = FnStubs.end();
633         i != e; ++i) {
634      SwitchToTextSection(".section __TEXT,__symbol_stub1,symbol_stubs,"
635                          "pure_instructions,16", 0);
636      EmitAlignment(4);
637      O << "L" << *i << "$stub:\n";
638      O << "\t.indirect_symbol " << *i << "\n";
639      O << "\tlis r11,ha16(L" << *i << "$lazy_ptr)\n";
640      if (isPPC64)
641        O << "\tldu r12,lo16(L" << *i << "$lazy_ptr)(r11)\n";
642      else
643        O << "\tlwzu r12,lo16(L" << *i << "$lazy_ptr)(r11)\n";
644      O << "\tmtctr r12\n";
645      O << "\tbctr\n";
646      SwitchToDataSection(".lazy_symbol_pointer", 0);
647      O << "L" << *i << "$lazy_ptr:\n";
648      O << "\t.indirect_symbol " << *i << "\n";
649      if (isPPC64)
650        O << "\t.quad dyld_stub_binding_helper\n";
651      else
652        O << "\t.long dyld_stub_binding_helper\n";
653    }
654  }
655
656  O << "\n";
657
658  // Output stubs for external and common global variables.
659  if (GVStubs.begin() != GVStubs.end()) {
660    SwitchToDataSection(".non_lazy_symbol_pointer", 0);
661    for (std::set<std::string>::iterator I = GVStubs.begin(),
662         E = GVStubs.end(); I != E; ++I) {
663      O << "L" << *I << "$non_lazy_ptr:\n";
664      O << "\t.indirect_symbol " << *I << "\n";
665      if (isPPC64)
666        O << "\t.quad\t0\n";
667      else
668        O << "\t.long\t0\n";
669
670    }
671  }
672
673  // Emit initial debug information.
674  DW.EndModule();
675
676  // Funny Darwin hack: This flag tells the linker that no global symbols
677  // contain code that falls through to other global symbols (e.g. the obvious
678  // implementation of multiple entry points).  If this doesn't occur, the
679  // linker can safely perform dead code stripping.  Since LLVM never generates
680  // code that does this, it is always safe to set.
681  O << "\t.subsections_via_symbols\n";
682
683  AsmPrinter::doFinalization(M);
684  return false; // success
685}
686
687